12-Comparison of kinetics, activity and stability of Ni_HZSM-5 and Ni_Al2O3-HZSM-5
Comparison of kinetics,activity and stability of Ni/HZSM-5and Ni/Al 2O 3-HZSM-5for phenol hydrodeoxygenation
Chen Zhao,Stanislav Kasakov,Jiayue He,Johannes A.Lercher ?
Catalysis Research Center and Department of Chemistry,Technische Universit?t München,Garching 85747,Germany
a r t i c l e i n f o Article history:
Received 14June 2012Revised 20August 2012Accepted 21August 2012
Available online 13October 2012Keywords:
Dealumination Al 2O 3binder React IR
Phenol hydrodeoxygenation
a b s t r a c t
We have investigated the detailed kinetics of phenol hydrodeoxygenation in liquid aqueous medium over Ni supported on HZSM-5or HZSM-5with 19.3wt.%c -Al 2O 3binder.The individual reaction steps on two Ni catalysts followed the rate order r 1(phenol hydrogenation) ó2012Published by Elsevier Inc. 1.Introduction Awareness of global warming and diminishing crude oil reserves promotes focus on alternative sustainable fuel supplies.Biomass to liquid (BtL)process is a promising route to produce high-energy density fuels [1].Usually,two methods are applied for bio-oil production,(i)fast pyrolysis or liquefaction of biomass at ?xed condition (temperature >700K)[2];(ii)catalytic depoly-merization of biomass at relatively milder conditions [3].The depolymerized moieties,however,are prone to repolymerize to form tars via radical reactions even at ambient temperature.Recently,we developed a novel method using boric acid as a pro-tecting agent to hydrolyze lignin in alkaline aqueous solution,achieving a phenolic monomer yield up to 85wt.%[4].In the step following hydrolysis,selective hydro-processing,for example,the hydrodeoxygenation (HDO)technique for removing the high oxygen content (up to 50wt.%)in biomass [1,5],is required for hydrocarbon production.The traditional hydrotreating catalysts such as sul?ded CoMo and NiMo,however,leach sulfur and are rapidly deactivated by oxygenates and ubiquitous water [6]. Sulfur-free bifunctional catalysts with metal and acid sites have been developed for hydrodeoxygenation via consecutive hydroge-nation and dehydration steps at mild conditions (473–523K,4MPa H 2).Our ?rst generation catalysts combined Pd/C (noble me-tal)and H 3PO 4(aq)[7,8],progressing to the second generation com-prising bulk Raney Ni (base metal)together with Na?on/SiO 2(solid acid)[9].Recently,we developed the third-generation Pd/HZSM-5and Ni/HZSM-5catalysts [10–12],which were effective,scalable,and stable for the target hydrodeoxygenation processes. To enhance the hydrodeoxygenation activity,we have incorpo-rated Ni particles into the HZSM-5support with a 19.3wt.%frac-tion of c -Al 2O 3binder.Herein,we compared the detailed kinetics of elementary steps involved in phenol hydrodeoxygenation over Ni/HZSM-5and Ni/Al 2O 3-HZSM-5catalysts.In addition,in situ IR spectroscopy was used to monitor the overall phenol hydrodeoxy-genation.The hydrodeoxygenation was also tested on lignin-derived substituted phenols such as guaiacols.The tendency to leach Ni and weight loss was measured at the reaction hydrother-mal conditions in the autoclave reactor or with acetic acid in the Soxhlet apparatus.In addition,the catalyst stability was evaluated by recovering catalyst and then starting new batch runs.Associ-ated changed metal sites were diagnosed by TEM,and changed acid sites were measured by IR of adsorbed pyridine.2.Experimental 2.1.Chemicals All chemicals were purchased from commercial suppliers:phe-nol (Sigma–Aldrich,99.5%),cyclohexanone (Sigma–Aldrich,99%),cyclohexanol (Sigma–Aldrich,99%),cyclohexene (Sigma–Aldrich, 0021-9517/$-see front matter ó2012Published by Elsevier Inc.https://www.wendangku.net/doc/a7524889.html,/10.1016/j.jcat.2012.08.017 Corresponding author.Fax:+498928913544. E-mail address:johannes.lercher@ch.tum.de (J.A.Lercher). 99%),4-n-propylguaiacol(SAFC,>99%),Ni(NO3)2á6H2O(Sigma–Al-drich,99%),HZSM-5(Süd Chemie AG München,powder,0.5l m), and bound HZSM-5(c-Al2O3-HZSM-5,Süd Chemie AG München, cylindrical pellet5mm?5mm?3cm).The Si/Al ratio in the HZSM5was90.The binder was c-Al2O3comprising21.2wt.%of the pellets.Gases in this study included air(Air Liquide, 20.5vol.%O2and79.5%vol.%N2),N2(Air Liquide,>99.999%),He (Air Liquide,>99.999%),and H2(Air Liquide,>99.999%). 2.2.Catalyst preparation A9.2wt.%Ni/HZSM-5(BET surface area:383m2gà1),7.0wt.% Ni/Al2O3-HZSM-5(BET surface area:360m2gà1),and9.3%Ni/ Al2O3-HZSM-5(BET surface area:351m2gà1)catalysts were pre-pared by the wetness impregnation method.Ni(NO3)2á6H2O (20g)was dissolved in water(20ml),and the aqueous solution was slowly dropped into HZSM-5or Al2O3-HZSM-5with stirring. After the metal incorporation for2h,the catalyst was dried at 373K for12h,air-calcined(?ow rate:100ml minà1)at673K for 4h,and reduced under a H2?ow(?ow rate:100ml minà1)at 733K for4h with a heating rate of2K minà1. 2.3.Catalyst characterization 2.3.1.Atomic absorption spectroscopy(AAS) Atom absorption spectroscopy with a UNICAM939AA-Spec-trometer determined the Ni content of the catalysts and Ni concen-trations in water for the leaching experiments. 2.3.2.Infrared(IR)spectroscopy of adsorbed pyridine IR spectra of adsorbed pyridine were measured on a Perkin–El-mer2000spectrometer operated at a resolution of4cmà1.The cat-alyst samples were activated in vacuum(p=10à6mbar)at673K for1h before the IR investigation.The activated catalyst samples were then exposed to pyridine(p Py=10à1mbar)at423K for 0.5h.The spectra were recorded at423K after evacuation for 1h,continuing sweeps until equilibrium was achieved.The con-centrations of Br?nsted acid sites(BAS)and Lewis acid sites(LAS) are determined from the integrated intensities of peaks at ca. 1540cmà1and1450cmà1,respectively.The molar extinction coef-?cients published by Emeis were used for quanti?cation[13]. 2.3.3.Transmission electron microscopy(TEM) For TEM measurements,an ultrasonicated methanol suspension of the solid samples was dropped onto a carbon-coated Cu grid. The TEM images were recorded on a JEM-2010Jeol transmission microscope operated at120kV.300particles were counted for size calculation. 2.3.4.H2.chemisorption Before the H2chemisorption,the reduced Ni catalysts were acti-vated in vacuum at588K for1h and then cooled to ambient tem-perature.Subsequently,the H2adsorption isotherm was measured between1and40kPa.The sample was then outgassed at ambient temperature for1h,and a second isotherm measured physisorbed hydrogen.The hydrogen chemisorbed on Ni was the difference be-tween intercepts of the isotherms extrapolated to zero H2pressure. Ni dispersions were estimated assuming chemisorption stoichiom-etry of H/Ni surf=1. 2.4.Catalytic measurements 2.4.1.Kinetic study of phenol hydrodeoxygenation network Based on the reaction network of aqueous-phase hydrodeoxy-genation of phenol to cyclohexane over Ni/HZSM-5[7–10], the kinetic study was separated into four steps:(i)phenol hydrogenation,(ii)cyclohexanone hydrogenation,(iii)cyclohexa-nol dehydration,and(iv)cyclohexene hydrogenation.For reaction measurements quantities of reactants,catalysts in80ml H2O were as follows:(a)phenol(5.0g),Ni/Al2O3-HZSM-5(0.1g);(b)cyclo-hexanone(10.0g),Ni/Al2O3-HZSM-5(0.050g);(c)cyclohexanol (12.5g),Ni/Al2O3-HZSM-5(0.050g);and(d)cyclohexene (35.0g),Ni/Al2O3-HZSM-5(0.050g). A typical reaction was carried out in an autoclave batch reactor (Parr,Series4843,300ml).After loading the reactant,catalyst,and water,the reactor was?ushed three times with N2.At reaction temperature,H2was charged to5MPa and the reaction time initi-ated.Each of the hydrodeoxygenation intermediates was reacted individually for20,40,60,80,100,and120min at a stirring speed of700rpm.For calculation of apparent activation energies,the reactions were measured at433,453,473to493K and reaction times of100min. After the reactor was cooled to room temperature,the H2pres-sure was released and the organic phase was extracted with ethyl acetate(3?20ml).The organic phase and the carbon balance in the aqueous phase were analyzed by gas chromatography(GC,Shi-madzu2010)with a HP-5capillary column(30m?250l m)and ?ame ionization detector(FID).In addition,a gas chromato-graph–mass spectrometer(GC–MS,Shimadzu QP2010S)was used to identify the organic compounds.Since it is a biphasic reaction, these kinetic data were collected after separate batch runs with different duration times and temperatures.The gas phase was determined by GC(HP6890)equipped with a plot Q capillary col-umn(30m?250l m)with thermal conductivity detector(TCD). 2.4.2.In situ IR spectroscopic studies of phenol hydrodeoxygenation The in situ IR spectroscopic study used the React IR device(Met-tler Toledo,React IR1000)coupled to a Parr reactor(100ml).A dia-mond placed in the bottom of the autoclave was used as a probe to collect the in situ IR spectra in the liquid phase.First,a background spectrum was collected at reaction conditions(473K,4MPa H2) with0.5g catalyst dispersed in50ml water.Then,the autoclave reactor was loaded with the reactant phenol(5.0g),and H2 (4MPa)was charged into the system after reaction temperature (473K)had reached.The spectra were collected at every10min for360min.To normalize the IR absorbance value,for example, the phenol adsorption intensities at1231cmà1are recorded as A1,A2,A3,A4,...and the normalized values are1,A2/A1,...,A n/A1. For normalizing cyclohexanone(B1,B2,B3,B4)adsorption intensi-ties at1698cmà1,the normalized values are0,(B2àB1)/B1-,...,(B nàB1)/B1.Cyclohexanol intensity normalization is similar to the treatment on cyclohexanone adsorption. 2.4. 3.Hydrodeoxygenation of phenol and substituted phenol monomers In the typical experiment for hydrodeoxygenation of phenol and substituted phenol monomers,?rst a mixture of reactant (0.01mol),H2O(80ml),and Ni/HZSM-5or Ni/Al2O3-HZSM-5 (0.5g)was charged into the reactor.After?ushing the reactor with H2three times,reaction started at473or523K in4MPa H2and continued for0.5h.After reaction,the workup was as described in Section2.4.1. 2.4.4.Catalyst leaching at the hydrothermal and acidic hydrothermal conditions The leaching of Ni/HZSM-5and Ni/Al2O3-HZSM5catalysts was tested in a Soxhlet apparatus equipped with a Whatman extraction thimble(33?130mm,thickness1.5mm)loaded with2.0g cata-lyst,and water(350ml)or an acetic acid aqueous solution (15wt.%,350ml)in the two-necked round bottom?ask(500ml). After the system began to re?ux,a3ml aliquot was collected at every12h for120h. C.Zhao et al./Journal of Catalysis296(2012)12–2313 Ni leaching was also evaluated in the autoclave loaded with 2.0g catalysts in80ml water at473K under H2(4MPa)and stirred at700rpm,for72h.AAS was used to analyze the Ni concentration in the aqueous phase and in remaining Ni catalysts,and the weight losses of the Ni catalysts before and after hydrothermal treatment were also measured. 2.4.5.Catalyst recycle Catalyst recycling procedure for phenol hydrodeoxygenation was as follows:a mixture of phenol(8.0g),catalyst(2.0g),and water(80ml)was loaded into the autoclave and then reacted at 473K in presence of5MPa H2at a stirring speed of700rpm for 30min.After the?rst reaction run,the organic phase was ex-tracted by ethyl acetate and analyzed by GC and GC–MS.The cat-alyst was separated from the aqueous phase by centrifugation, and$0.1g of the used catalyst was sampled to characterize the catalyst state by TEM and IR spectroscopy of adsorbed pyridine. The catalyst was then washed by acetone and water,dried at 383K overnight,and activated in H2before its reuse in the next run.Four recycling runs were conducted in the present work for phenol hydrodeoxygenation with Ni/HZSM-5and Ni/Al2O3-HZSM-5catalysts. 3.Results and discussion 3.1.Characterization of catalyst properties Physical characteristics of the two Ni catalysts are summarized in Table1.The Ni contents were9.2and9.3wt.%for Ni/HZSM-5 and Ni/Al2O3-HZSM-5catalysts,respectively,with HZSM-5frame-work Si/Al ratios of90.The Al2O3-HZSM-5support contained 21.2wt.%Al2O3binder,which was decreased to19.3wt.%after me-tal incorporation. The Br?nsted(BAS)and Lewis acid sites(LAS)were distin-guished and quanti?ed by IR spectra of adsorbed pyridine(Py-IR).The BAS concentration of Ni/Al2O3-HZSM-5(45l mol gà1) was65%of that of Ni/HZSM-5(70l mol gà1).Conversely,the LAS concentration of Ni/Al2O3-HZSM-5(46l mol gà1)was more than double that of Ni/HZSM-5catalyst(21l mol gà1)due to the added Al2O3-binder. Determined by TEM images,the Ni0particle size of Ni/Al2O3-HZSM-5was8.8nm with a narrow standard deviation of1.6nm. By comparison,the mean Ni cluster size of Ni/HZSM-5catalysts was35nm with a much broader standard deviation of13nm. The metal dispersion(determined by H2chemisorption)in Ni/ Al2O3-HZSM-5(8.0%)was three times higher than in Ni/HZSM-5 (2.5%),agreeing quite well with TEM results. A more detailed comparative characterization on the supported Ni catalysts including the chemical composition(AAS),BET surface areas(N2sorption),morphology(SEM),crystalline(XRD),accessi-ble Ni sites(TEM,H2chemisorption and IR of adsorbed CO),acid sites(TPD of NH3and IR of adsorbed pyridine),metal-support interaction(TPR-H2),and adsorption capacities toward reactant and intermediates(IR of adsorbed species)has been displayed in the supporting information. 3.2.Phenol hydrodeoxygenation network Phenol hydrodeoxygenation involves the sequential reactions shown in Scheme1,phenol hydrogenation(Step1),cyclohexanone hydrogenation(Step2),cyclohexanol dehydration(Step3),and?-nal cyclohexene hydrogenation(Step4).We studied such sequence previously over the dual or bi-functional catalysts combining met-als Pd,Pt,Ru,Rh,and Ni together with mineral acids H3PO4and CH3COOH or solid acid Na?on[7–11],in aqueous solution at 473–523K in presence of H2.In the overall reaction,the metal sites catalyze the hydrogenations of phenol,cyclohexanone,and cyclo-hexene,and the acid sites dehydrate the intermediate cyclohexa-nol to cyclohexene.In the gas phase,hydrogenolysis of phenol and cyclohexanol forming benzene and cyclohexane,respectively, were common side-reactions over the supported Pt or Ni[14,15]. The hydrogenolysis and hydrogenation reactions were parallel, leading to a consequent complex reaction network.But hydrogen-olysis was negligible in the aqueous phase over the present Ni catalysts. 3.3.Kinetic of four elementary reactions in phenol hydrodeoxygenation 3.3.1.Phenol hydrogenation The rate of phenol hydrogenation was measured with a batch reactor at473K in presence of5MPa H2.To avoid the conversion during heating from ambient temperature,the hydrogen was introduced into the reactor after the required temperature was achieved and the reaction time was recorded from that time.After required time,the reaction was quenched by ice to ambient tem-perature in less than2min.Since these are always two-phase reac-tions,the rate data were collected at separate batch duration times, but not by in situ sampling.The reaction rates and turnover fre-quencies(TOFs)reported correspond to initial conversions. The rate data and E a calculation for phenol hydrogenation over two Ni catalysts are plotted in Fig.1,where conversion describes declining phenol concentration in the aqueous phase.The products included cyclohexanone,cyclohexanol,and cyclohexanes on the bifunctional Ni/Al2O3-HZSM-5catalysts,but no benzene.Also,no ring-opening products including C1A C6alkanes were found in the gas phase.Thus,with the present catalysts,hydrogenation but not hydrogenolysis was the exclusive route for phenol conversion. Fig.1shows that the conversion increased linearly during20–120min on both catalysts.Determined from the slopes in Fig.1, the initial rates of phenol hydrogenation over Ni/HZSM-5and Ni/ Al2O3-HZSM-5were14and61mmol gà1hà1,respectively.If the rates are normalized to per mole of surface Ni atoms,TOFs of indi-vidual reactions were respectively398and553mol molà1 Surf:Ni hà1. In our previous test with Pd/C[8],Pd showed a much higher TOF of4200hà1than Ni in Ni/HZSM-5(398hà1)at comparable condi-tions for phenol hydrogenation.The apparent activation energies Table1 Physical characteristics of supported Ni catalysts. Catalyst Composition(wt.%)Acidity(l mol gà1)a d Ni(nm)b D Ni(%)c Ni Al2O3binder Si/Al ratio in framework BAS LAS Ni/HZSM-59.2–90702135±13 2.5 Ni/Al2O3-HZSM-59.319.39045468.8±1.68.0 a Determined by IR spectra of adsorbed pyridine,BAS:Br?nsted acid site,LAS:Lewis acid site. b Determined by TEM images(300particles are counted for size calculation). c Determine d by H 2chemisorption. 14 C.Zhao et al./Journal of Catalysis296(2012)12–23 for the reaction steps were calculated from the TOFs at 423,453,473,and 493K.The activation energies for phenol hydrogenation were 48and 56kJ mol à1on Ni/HZSM-5and Ni/Al 2O 3-HZSM-5,respectively. 3.3.2.Cyclohexanone hydrogenation The rates of hydrogenation of cyclohexanone were measured at the same conditions (473K,5MPa H 2).The conversions graphed in Fig.2had linear increase against reaction time.Ni/Al 2O 3-HZSM-5yielded a much higher hydrogenation rate (159mmol g à1h à1)compared to Ni/HZSM-5(108mmol g à1h à1)for cyclohexanone hydrogenation,which follows the same hydrogenation trend in phenol.But the rates for cyclohexanone hydrogenation were much higher than those for phenol hydrogenation.If calculated from the exposed Ni atoms,the TOF on Ni/Al 2O 3-HZSM-5e1233mol mol à1Surf :Ni h à1 Twas much lower than that on Ni/HZSM-5 e2443mol mol à1Surf :Ni h à1 T.In the case of Pd/C catalyzed hydrogena-tion [8],the rate on cyclohexanone hydrogenation e21;000mol mol à1Surf :Pd h à1 Twas also much higher than that of phe-nol hydrogenation e4200mol mol à1Surf :Pd h à1 T. If considering that Ni/Al 2O 3-HZSM-5showed ?ve times higher phenol hydrogenation rates compared to Ni/HZSM-5,it is also indi-cated that the cyclohexanone hydrogenation on Ni/Al 2O 3-HZSM-5was dramatically suppressed in which only shows a rate ratio of 1.5times to Ni/HZSM-5.It has been reported that Lewis acids such as AlCl 3favor stabilizing the cyclohexanone [16],which would suppress the keto-enol isomeric equilibrium shift toward cyclohexanol formation.IR spectroscopy [16]showed that the absorption band of the C @O stretching vibration shifted from 1714cm à1in the absence of AlCl 3to 1624cm à1in the presence of AlCl 3,which is attributed to the coordination of the Lewis basic C @O group to the Lewis acid.Thus,the cyclohexanone hydrogena-tion rate is concluded to be kinetically hindered in the presence of a high fraction of Al 2O 3binder (Lewis acid sites)over Ni/Al 2O 3-HZSM-5.In addition,the apparent activation energies for cyclohexanone hydrogenation were 142and 129kJ mol à1on Ni/Al 2O 3-HZSM-5and Ni/HZSM-5(see Fig.2),respectively. 3.3.3.Cyclohexanol dehydration The conversion versus time and the Arrhenius graphs for cyclo-hexanol dehydration over Ni/Al 2O 3-HZSM-5and Ni/HZSM-5cata-lysts are shown in Fig.3.The dehydration rate on Ni/HZSM-5 C.Zhao et al./Journal of Catalysis 296(2012)12–2315 (528mmol gà1hà1)was much higher than on Ni/Al2O3-HZSM-5 (354mmol gà1hà1).In our previous work,we compared the cyclo-hexanol dehydration rates over c-Al2O3,amorphous silica alumina (ASA),Na?on,and Amberlyst in water at200°C,and the results showed that Br?nsted acid sites(BAS)were active sites for dehy-dration in hot water and Lewis acid sites(LAS)on c-Al2O3were al-most inactive for such reaction in aqueous phase[10].Thus,the higher dehydration rate on Ni/HZSM-5is attributed to its higher concentrations of BAS(0.070mmol gà1)than with Ni/Al2O3-HZSM-5(0.045mmol gà1)(Table1),and these BAS were in closer proximity to the metal sites in the catalyst Ni/HZSM-5without the binder.If normalized to the concentration of BAS,the respective dehydration TOFs were7428and8333mol molà1 BAS hà1on Ni/HZSM-5and Ni/ Al2O3-HZSM-5,respectively.In previous study with Pd/C and H3PO4bifunctional catalysts[8],it was shown that the dehydration step was rate determining for overall phenol hydrodeoxygenation with a low dehydration TOF of15mol molà1 Ht hà1over H3PO4. But in this case with HZSM-5-based catalysts,the dehydration rates(TOF)are500times higher compared to H3PO4.Without Ni, on the pure HZSM-5,the dehydration rate was1600mol molà1 BAS hà1[10],which was much slower than Ni incorporated Ni/HZSM-5e7428mol molà1 BAS hà1T.This indicates that the dehy-dration–hydration occurs in an equilibrium in an aqueous solution, and the additional Ni consumes the dehydrated cyclohexene and accelerates,so the dehydration rate to some extent.The dehydra-tion activation energies on two present catalysts were indistin-guishable at112and114kJ molà1. Dehydration of an alcohol might be inhibited in liquid water. But here,the dehydration rate is greatly enhanced with porous material zeolite compared to other solid acids such as Amberlyst, Na?on,H2SO4/ZrO2,and heteroploy acid[10],which is mainly attributed to the fact that either the cyclohexanol adsorption is highly enhanced on HZSM-5active sites than other Br?nsted solid acids[10,11]or the narrow pore of HZSM-5prevents the formation of alcohol oligomer,and hence promotes the equilibrium shift to toward alcohol monomer formation and accelerates,so the dehy-dration rates[17]. 3.3. 4.Cyclohexene hydrogenation The fourth step involves the hydrogenation of C@C double bonds of cyclohexene in water over Ni metal sites.The conversions are plotted in Fig.4,in which the hydrogenation rate on Ni/Al2O3-HZSM-5(2156mmol gà1hà1)was slightly faster than that on Ni/ HZSM-5(1813mmol gà1hà1).This result agrees with the reaction on hydrogenation of phenol and cyclohexanone where Ni/Al2O3-HZSM-5was more active.The conversion(even up to60%)was linear against reaction time,indicating zero reaction order for cyclohexene hydrogenation over both catalysts.The TOFs on Ni/Al2O3-HZSM-5and Ni/HZSM-5were20.287and55;136mol molà1 Surf:Ni hà1,which is approximately one tenth of the rate of Pd catalyzed cyclohexene hydrogenation with a TOF of200,000hà1 [8].The obtained E a were comparable at35and25kJ molà1, respectively. 3.3.5.Summarized kinetic data for phenol hydrodeoxygenation reaction network The rate data for the four steps over the Ni catalysts were sum-marized in Table2.The four reactions in aqueous phase were either:(i)hydrogenations of phenol,cyclohexanone,and cyclohex-ene,without hydrogenolysis,or(ii)dehydration of cyclohexanol. The active hydrogenation sites were on the exposed Ni nanoclus-ters,while the dehydration was catalyzed by the BAS sites that were associated with the HZSM-5.In three hydrogenation reac-tions,Ni/Al2O3-HZSM-5was consistently more active compared 16 C.Zhao et al./Journal of Catalysis296(2012)12–23 to Ni/HZSM-5.This is assigned to two factors.First,the Ni/Al2O3-HZSM-5catalyst had three times more accessible Ni sites than Ni/HZSM-5veri?ed by IR spectroscopy of adsorbed CO(see Table S2and Fig.S6).The second is related to the fact that Ni/ Al2O3-HZSM-5had higher adsorption capability for phenol,cyclo-hexanone,and cyclohexanol than Ni/HZSM-5(see Table S3).The phenol or ketone hydrogenation reactions usually showed positive reaction orders in organic and H2concentrations in the previous literature[18],suggesting that the hydrogenation rates on phenol over Ni/Al2O3-HZSM-5would be much higher.But the Lewis acid Al2O3binder may have stabilized the ketone and inhibited its hydrogenation(Fig.2).In addition,the cyclohexene hydrogenation had zero reaction order,and thus,cyclohexene hydrogenation rates on the two Ni catalysts were similar(Fig.4). The dehydration reaction rate on Ni/HZSM-5was slightly faster due to higher BAS density than on Ni/Al2O3-HZSM-5,but the apparent E a on the catalysts were almost identical(112and 114kJ molà1).It should be emphasized that the four elementary steps all showed comparable E a s on two Ni catalysts,and this is re-lated to the fact that the adsorption heat of both reactant and prod-uct that could in?uence the apparent activation energy should be principally comparable,as the active sites and their surroundings are quite similar.The rates of phenol hydrodeoxygenation elemen-tary steps on two Ni supported catalysts increased in the order as phenol hydrogenation 3.4.Kinetics of overall phenol hydrodeoxygenation over Ni catalyst 3.4.1.Time-resolved in situ IR spectroscopy study Phenol hydrodeoxygenation was also monitored with time-re-solved in situ IR spectroscopy.A catalyst charge of0.5g and 1.2MPa H2(equipment limit)was employed in the in situ IR mea-surement.The time-resolved IR spectra measured during phenol hydrodeoxygenation over Ni/HZSM-5and Ni/Al2O3-HZSM-5cata-lysts are shown in Fig.5a and b,respectively.The speci?c peaks for phenol(1231cmà1,aromatic OH bond stretch),cyclohexanone (1698cmà1,C@O stretch),and cyclohexanol(1014cmà1,alicyclic OH stretch)were monitored to?ow concentrations of respective reactants.With increasing reaction time,the intensity of the IR peaks at1698cmà1(cyclohexanone)and1014cmà1(cyclohexa-nol)both increased and the intensity at1231cmà1(phenol)de-clined.The detected concentrations of intermediates remained low.Cyclohexene and cyclohexane were not detected because the diamond probe was in the aqueous phase,but those species segregated to the upper organic phase. In the separate preliminary experiment,we have demonstrated that the substance(phenol,cyclohexanone,and cyclohexanol)con-centration was proportional to the IR light absorbance,thus the normalized absorption value was plotted with the reaction time to re?ect a changing concentration pro?le(see Fig.5).Seen from Fig.5,it can be obviously observed that the slope of decreasing phenol concentration was much sleeper with Ni/Al2O3-HZSM-5 than that with Ni/HZSM-5,in which the former phenol conversion rate(31.9mmol gà1hà1)was8.3times higher than the latter one (3.8mmol gà1hà1). 3.4.2.Impact of reaction time For the reaction carried out in the batch autoclave,it was quenched after various reaction times to measure directly the con-centrations of intermediates and products(Fig.6).At t=0,the pri-mary products were hydrogenated cyclohexanone(ca.65% selectivity)and cyclohexanol(ca.35%selectivity)from both Ni-based catalysts.In agreement with the in situ IR study,Ni/Al2O3-HZSM-5delivered higher initial phenol conversion rate (117mmol gà1hà1)than Ni/HZSM-5(21mmol gà1hà1).After3h, reaction was complete over Ni/Al2O3-HZSM-5,while Ni/HZSM-5 only attained72%yield.Note that these obtained rates for phenol hydrogenation monitored by GC were much higher than the data from reactions monitored by in situ IR spectroscopy,attributing to the applied higher hydrogen pressure(5vs.1.2MPa)in the for-mer case.Cyclohexene intermediate was observed with selectivity lower than10%,and by comparison cyclohexene was not detected at all with Pd-catalyzed phenol hydrodeoxygenation[7,8],which is related to the one tenth activity for cyclohexene hydrogenation on Ni/HZSM-5(2?104hà1)compared to that on Pd/C(2?105hà1).It has been found that cyclohexane quickly dominated the product distribution(70–80%)at30–80%conversions,and the primary products of cyclohexanone and cyclohexanol decreased to quite low selectivity(5–10%)in a short time.This also?ts for the com-parison of elementary step rates in experimental kinetics moni-tored by GC and in situ IR spectroscopy that the increasingly faster r1to r4would lead to the?nal cyclohexane to be highly selective during phenol conversion. 3.4.3.Impact of reaction temperature The product distributions from the two catalysts at433,453, 473,and493K and100min were measured directly(Fig.7).At 433K,Ni/HZSM-5led to2%conversion with a high selectivity of 90%cyclohexanone.The hydrogenation activity of Ni/Al2O3-HZSM-5attained 2.5times higher conversion(5%)than Ni/ HZSM-5under the same conditions.At the higher temperatures, the cyclohexanone concentration at the end of100min decreased relative to the increase in cyclohexene and cyclohexane.Generally, Ni/Al2O3-HZSM-5showed much higher temperature dependence toward hydrogenation(conversion from10%to35%)at tempera-tures from433to493K,while Ni/HZSM-5led to only the slight in-crease from5%to10%at identical conditions.This is characteristic Table2 TOF and E a data for aqueous-phase phenol hydrodeoxygenation reaction network at 473K on Ni catalysts. Reaction Ni/HZSM-5Ni/Al2O3-HZSM-5 Step1:Phenol hydrogenation r1(mmol gà1hà1)1461 TOF1emol molà1Surf:Ni hà1T398553 E a1(kJ molà1)4856 Step2:Cyclohexanone hydrogenation r2(mmol gà1hà1)108159 TOF2emol molà1Surf:Ni hà1T24431233 E a2(kJ molà1)142129 Step3:Cyclohexanol dehydration r3(mmol gà1hà1)528354 TOF3emol molà1BAS hà1T74288333 E a3(kJ molà1)112114 Step4:Cyclohexene hydrogenation r4(mmol gà1hà1)18132156 TOF4emol molà1Surf:Ni hà1T55,13620,287 E a4(kJ molà1)3525 C.Zhao et al./Journal of Catalysis296(2012)12–2317 of a higher activation energy occurs on Ni/Al 2O 3-HZSM-5(56kJ mol à1)compared to Ni/HZSM-5(48kJ mol à1). 3.5.Hydrodeoxygenation of substituted phenol monomers Besides phenol,we are also interested in the performance of these catalysts for hydrodeoxygenation of more complex substi-tuted phenols in aqueous medium.Depolymerized lignin products include alkyl-and methoxy-substituted phenols and here 4-n -pro-pylphenol and 4-n -propylguaiacol were selected as model com-pounds to evaluate the two Ni catalysts (Table 3).The alkyl phenol reacted as fast as phenol.The Ni/Al 2O 3-HZSM-5and Ni/HZSM-5delivered C 9hydrocarbon yields of 100%and 43%,respec-tively,after 0.5h at 473K.Even employed with only 7wt.%Ni,the Al 2O 3-HZSM-5support delivered a 49%C 9hydrocarbons yield in 0.5h at 473K,still higher than 9wt.%Ni/HZSM-5at the same conditions. The 4-n -propylguaiacol,with both alkyl and methoxy groups on the phenol ring,reacted more slowly than phenol on the Ni cata-lysts.Conversions in 0.5h at 473K decreased to 15%with a selec-tivity of 3.7%C 9hydrocabons on Ni/HZSM-5catalysts,and Ni/Al 2O 3-HZSM-5led to a conversion of 26%with a selectivity of 15%C 9hydrocarbons.This dramatically decreased activity is attrib-uted to the increased stability of aromatic-ring with the added methoxy group,agreeing with our former results on hydrodeoxy-genation of phenolic compounds over Pd catalysts that methoxy-substituted phenol is more stable and requires higher temperature for further conversion [8].At 523K,the conversions were in-creased to 21%and 55%with 100%selectivity to C 9hydrocarbons.When the reaction was extended to 2h,the conversion increased to 43%on Ni/HZSM-5and to 62%on Ni/Al 2O 3-HZSM-5with 100%alkane selectivity.The conversion to alkanes was increased to (a) Ni/HZSM-5 OH O OH 1698 cm -1 1231 cm -1 1014 cm -1 (b) Ni/Al 2O 3-HZSM-5 OH O OH 1698 cm -1 1231 cm -1 1014 cm -1 0.4 0.60.81.01.2m a l i z e d a b s . v a l u e Phenol (1231cm -1) 0.40.50.60.70.80.91.0 r m a b s . v a l u e Phenol (1231cm -1) Cyclohexanol (1014 cm -1) 18 C.Zhao et al./Journal of Catalysis 296(2012)12–23 100%in 2h when the Ni loading was increased to 20wt.%on HZSM-5at identical conditions [12].3.6.Catalyst test in the recycling runs 3.6.1.Catalyst activity For testing the activity in the recycling runs,the catalysts were separated by centrifugation,washed with acetone and then deion-ized water to remove organics,and dried in ambient air at 383K overnight.It has been observed after reaction at 473K for 0.5h in water that the used catalysts had become gray due to the surface oxidation of Ni during hydrothermal treatment.Before use in the next run,the Ni catalysts were calcined in air at 673K and acti-vated again in H 2carrier gas at 733K,and subsequently,they turned to be black again.In subsequent runs at 473K,the Ni/Al 2O 3-HZSM-5and Ni/HZSM-5catalysts attained ca.70%and 45%alkane formation,respectively (Fig.8a).The alkane yields gradually decreased from 70%to 25%in four consecutive recycle runs on Ni/Al 2O 3-HZSM-5,while such yields decreased from 30%to 10%on Ni/HZSM-5during sequential four catalytic recycle runs at the same conditions.If we compare the reaction rate variation during the catalyst recycling (see Fig.8b),the activity of Ni/Al 2O 3-HZSM-5 0% 10% 20% 30% 40% 0% 20%40% 60% 80% 100%433 453 473 493 Temperature (K) (a)Ni/HZSM-5as catalysts 0% 10% 20% 30% 40% 0% 20% 40% 60% 80% 100% 433453473493 Temperature (K) (b)Ni/Al 2O 3-HZSM-5as catalysts -ol -ene -ane -ol -ene -ane -one -one Ni/HZSM-5(a)and Ni/Al 2O 3-HZSM-5(b)as a function of temperature.453,473,493K,5MPa H 2,100min,stirred at 700rpm. Table 3 Hydrodeoxygenation of lignin-derived substituted phenols on Ni catalysts.a Reactant T (K)Catalyst Ni loading (wt.%)Conv.(%)Select (C%) C 9hydrocarbon 4-n -Propylphenol 473Sample 17.0491004-n -Propylphenol 473Sample 29.3431004-n -Propylphenol 473Sample 19.21001004-n -Propylguaiacol 473Sample 29.315 3.74-n -Propylguaiacol 473Sample 19.22610.84-n -Propylguaiacol 523Sample 29.3211004-n -Propylguaiacol 523Sample 19.2551004-n -Propylguaiacol c 523Sample 29.3431004-n -propylguaiacol c 523 Sample 1 9.2 62 100 a Reaction conditions:reactant (0.010mol),Ni/HZSM-5(2.0g)or Ni/Al 2O 3-HZSM-5(2.0g),H 2O (80ml),473K,5MPa H 2,30min,stirred 700rpm. b Sample 1:Ni/Al 2O 3-HZSM-5,Sample 2:Ni/HZSM-5.c Reaction time:2h. C.Zhao et al./Journal of Catalysis 296(2012)12–2319 decreased from270mol mol Nià1hà1to70mol mol Nià1 hà1after four catalytic runs,while the other activity of fresh Ni/HZSM-5 started from70mol mol Nià1hà1and decreased to50,30,and 20mol mol Nià1hà1after the sequential hydrothermal runs.In the following,we examine changes of catalyst weight,metal sites, and acid sites between the fresh and used catalysts. 3.6.2.Catalyst stability during the recycling runs To understand deactivation during the four recycling runs,we investigated catalyst physical changes including metal and support losses by leaching at hydrothermal conditions and acid site loss be-tween the fresh and used catalysts. 3.6.2.1.The Ni and zeolite leaching under acidic hydrothermal conditions.These Ni catalysts were developed for hydrothermal operation in liquid aqueous phase,so Ni and Al leaching were ?rstly investigated.Catalysts(2.0g)were loaded with350ml deionized water into the Soxhlet apparatus,and the Ni concentra-tions in the aqueous phase extracted by re?ux were measured by AAS(Fig.9a).The Ni leaching from Ni/Al2O3-HZSM-5was much slower than from Ni/HZSM-5,leaving1.5or5ppm respectively in solution https://www.wendangku.net/doc/a7524889.html,pared to the original loading of9.2–9.3wt.%Ni,Ni/Al2O3-HZSM-5retained9.0wt.%Ni but Ni/HZSM-5 only8.2wt.%Ni.The total catalyst weight losses were also com-pared(Table4).The weight loss from Ni/HZSM-5was less than 2%after90h re?ux in water,consistent with our recent results on the stability comparison of zeolites HZSM-5and HY in hydro-thermal conditions[19].In contrast,Ni/Al2O3-HZSM-5lost 7wt.%,attributed to extra-framework dealumination during the hydrothermal treatment.When the two catalysts were treated in the autoclave at473K for72h,Ni/HZSM-5was quite stable with the catalyst loss lower than0.1wt.%,while Ni/Al2O3-HZSM-5lost a much higher fraction of7.4wt.%.The remaining Ni contents were 7.7and8.7wt.%on Ni/HZSM-5and Ni/Al2O3-HZSM-5,respectively, indicating that the Ni particles on Al2O3-HZSM-5are more stable at hydrothermal conditions than those on HZSM-5. Summarizing these results allows us to conclude that(i)the Ni metal sites are much more stable to aqueous leaching on Al2O3-HZSM-5,and(ii)HZSM-5was stable in hot water,but the Al2O3 binder partly dissolved under these conditions.The stability of Ni ions in hot water was mainly related to the interaction of Ni metal and HZSM-5support.The TPR results(see Fig.S7)demonstrated that Ni/Al2O3-HZSM-5had a stronger interaction between metal and support and the Ni oxide on Al2O3-HZSM-5was more dif?cult to reduce.The strong interaction with Al2O3evidently stabilized the Ni on Al2O3-HZSM-5against leaching by water at473K. As the crude bio-oil contains acetic acid,the stability of Ni cat-alysts has also been tested by dilute aqueous15wt.%acetic acid solution at373K in the Soxhlet apparatus.The results are plotted at Fig.9b.The dilute acid leached more Ni than the deionized water and only6.9and6.5wt.%Ni remained on Ni/HZSM-5and Ni/Al2O3-HZSM-5after90h,respectively.The690ppm Ni leaching was detected by AAS in the aqueous solution after the continuous treat-ment for Ni/Al2O3-HZSM-5with acetic acid,whereas Ni/HZSM-5 showed a smaller amount of nickel leaching(580ppm).The origi-nal color of Ni catalysts turned from black to almost white after acetic acid re?ux.The total catalyst weight loss reached13wt.% from Ni/HZSM-5and18wt.%from Ni/Al2O3-HZSM-5after90h of acid re?ux.Ni losses were2.3wt.%and2.7wt.%,and the losses of the Al A Si oxide support were so determined to be10.7wt.% and15.3wt.%for Ni/HZSM-5and Ni/Al2O3-HZSM-5catalysts dur-ing such treatment,respectively.In principle,carboxylic acids che-late3d metal cations and thereby promote both dissolution and oxidation of Ni-based zeolite catalysts.We conclude that these cat-alysts are not stable enough for one-pot hydrodeoxygenation of lignin-derived phenolic residues that carry a high concentration of carboxylic acids. 20 C.Zhao et al./Journal of Catalysis296(2012)12–23 3.6.2.2.Metal site changes during the recycling runs.The evolution of Ni metal sites during successive runs was indicated in the TEM images (Fig.10a).Fresh Ni/Al 2O 3-HZSM-5showed a mean size Ni particle size of 8.8nm and Ni/HZSM-5mean size of 35nm.During the four catalyst recycling runs,the Ni particle size on Ni/Al 2O 3-HZSM-5increased by 2nm per run and the distribution broadened from 1.3to 3.6nm after four runs (Fig.10b).The Ni particles on Ni/HZSM-5grew by 18nm per run and the distribution broadened from 13nm to 33nm after four runs (Fig.10b).Under water or acid re?ux,the growth of Ni particles on Ni/Al 2O 3-HZSM-5was slower than on Ni/HZSM-5,so Ni/Al 2O 3-HZSM-5is more resistant to sin-tering compared to Ni/HZSM-5during catalyst recycling. 3.6.2.3.Acid site change during the recycling runs.The IR spectros-copy of adsorbed pyridine was applied to evaluate changes in acid sites during the recycling runs.IR spectra of adsorbed pyridine were measured at 413K in presence of 0.1mbar pyridine Table 4 Catalyst changes under hydrothermal conditions in Soxhlet apparatus and autoclave reactor. At 408K a With acetic acid at 408K a At 473K b Ni/HZSM-5(9.2wt.%)Catalyst loss (wt.%) <2.013<0.1Remaining Ni content (wt.%)8.2 6.97.7Ni concentration in water (ppm) 6.0580–Ni/Al 2O 3-HZSM-5(9.3wt.%)Catalyst loss (wt.%) <7.0187.4Remaining Ni content (wt.%)9.0 6.58.7Ni concentration in water (ppm) 2.0 690 – a Soxhlet apparatus,catalyst (2.0g),water (350ml),408K,90h. b Carried out at autoclave reactor,catalyst (2.0g),water (80ml),473K,5.0MPa H 2,72h. After Run 1 After Run 2 After Run 3 After Run 4 Fresh catalyst 200 nm 200 nm 100 nm 100 nm 100 nm 41 ±13 nm 59 ±24 nm 80 ± 28 nm 86 ± 30 nm 94 ±33 nm After Run 1 After Run 2 After Run 3 After Run 4 50 nm 50 nm 50 nm 50 nm 50 nm Fresh catalyst Ni/Al 2O 3-HZSM-5 8.8 ±1.3 nm 11 ± 2.5 nm 13 ± 2.9 nm 15 ± 3.1 nm 17 ± 3.6 nm 100120140 ) (b)Ni/HZSM-5Ni/Al 2O 3-HZSM-5 C.Zhao et al./Journal of Catalysis 296(2012)12–23 21 (Fig.11a)for assessing Br?nsted and Lewis acid sites as described above.The calculated results re?ected the kinetic change of acid sites (see Table 5).The ratios of BAS/LAS were decreased on both catalysts after four catalyst recycle runs.The acid site concentra-tions on both catalysts changed in the same fashion:(i)the LAS in-creased and the BAS decreased,(ii)the magnitudes of BAS and LAS changes (4l mol g à1run à1)during catalyst runs were the same on two catalysts.Thus,the sums of BAS and LAS (ca.90l mol/g à1)were nearly unchanged (Fig.11b). There are structural changes to HZSM-5during calcination in ?ow air.Above 723K,the dehydration formed Lewis acid sites at the expense of losing Br?nsted acid sites (Fig.11c).BAS and LAS are inter-convertible if the water adsorbed onto Br?nsted acid sites leading to hydroxyl group formation [20,21]during the catalyst regeneration process,but the LAS created here by calcinations 1700 1650 1600 1550 1500 1450 1400 Wavenumber (cm -1)A b s o r b a n c e Fresh 1547 1448 BAS LA S After 1 st Run A fter 2nd Run After 3rd Run After 4th Run Ni/HZSM-5 1650 1600 1550 1500 1450 1400 1700 Wavenumber (cm -1) A fter 3rd Run Fresh 1450 1546 BAS LA S A b s o r b a n c e After 4th Run After 2nd Run After 1st Run Ni/Al 2O 3-HZSM-5 1 2 3 4 5 BAS-Ni/HZSM-5 LAS-Ni/HZSM-5BAS-Ni/Al 2O 3-HZSM-5LAS-Ni/Al 22 O 3-HZSM-5 (c) Table 5 Acid site concentrations (unit:l mol g à1)in the fresh and reused catalysts from IR of adsorbed pyridine. LAS BAS Total acid sites B/L Ni/HZSM-5Fresh 217091 3.33After 1st run 216889 3.22After 2nd run 236284 2.71After 3rd run 375693 1.49After 4th run 364984 1.37Ni/Al 2O 3-HZSM-5Fresh 4645910.98After 1st run 5639940.70After 2nd run 6135950.57After 3rd run 6332950.51After 4th run 69 30 99 0.43 22 C.Zhao et al./Journal of Catalysis 296(2012)12–23 did not revert to the original Al A OH A Si structure(BAS)in presence of water.In fact,the change on the acid site hardly affected hydro-deoxygenation rates,because the dehydration catalyzed by BAS was much faster than other hydrogenation steps in the conversion of phenol to cyclohexane.Thus,in principle,catalyst deactivation majorly resulted from Ni sintering during the recycling runs. 4.Conclusion The rates of the four sequential reactions of phenol hydrodeox-ygenation were compared over two Ni catalysts.In three hydroge-nation reactions of phenol,cyclohexanone,and cyclohexene,Ni/ Al2O3-HZSM-5was more active than Ni/HZSM-5due to higher Ni dispersion on Ni/Al2O3-HZSM-5.The Al2O3binder introduced Le-wis acidity that stabilized a ketone intermediate and inhibited its hydrogenation.The cyclohexanol dehydration reaction rate on Ni/HZSM-5was slightly higher due to higher BAS concentration, and such dehydration was highly enhanced by close proximity be-tween acid sites and metal sites where cyclohexene is irreversibly hydrogenated. The reaction rates increased in the sequence of r1(phenol hydrogenation) The catalysts both deactivated due to Ni sintering during the hydrothermal and recycling process.Ni leaching into water at 473K was negligible from Ni/Al2O3-HZSM-5but more rapid from Ni/HZSM-5at identical conditions.Ni and Al A Si oxide components were extracted from both catalysts by15wt.%aqueous acetic acid above373K.During the recycling process,the Br?nsted acid sites comprising protonated oxide bridges as Al A OH A Si were dehy-drated by calcination to coordinately unsaturated Al atom Lewis acid sites. Acknowledgment This work was?nancially supported by the Technische Univer-sit?t München in the framework of the European Graduate School for Sustainable Energy. Appendix A.Supplementary material Supplementary data associated with this article can be found,in the online version,at https://www.wendangku.net/doc/a7524889.html,/10.1016/j.jcat.2012.08.017. References [1]D.C.Elliott,Energy Fuels21(2007)1792. 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C.Zhao et al./Journal of Catalysis296(2012)12–2323 学习并掌握Activity生命周期，对从事Android开发（或者打算日后从事这方面的开发工作）的朋友来讲，是至关重要的。本文将用图解和实例的方式，向大家详细讲解Activity 生命周期的有关知识。 Activity有三个状态： 1.当它在屏幕前台时（位于当前任务堆栈的顶部），它是激活或运行状态。它就是响应用户操作的Activity。 2.当它上面有另外一个Activity，使它失去了焦点但仍然对用户可见时（如图），它处于暂停状态。在它之上的Activity没有完全覆盖屏幕，或者是透明的，被暂停的Activity仍然对用户可见，并且是存活状态（它保留着所有的状态和成员信息并保持和窗口管理器的连接）。如果系统处于内存不足时会杀死这个Activity。 3.当它完全被另一个Activity覆盖时则处于停止状态。它仍然保留所有的状态和成员信息。然而对用户是不可见的，所以它的窗口将被隐藏，如果其它地方需要内存，则系统经常会杀死这个Activity。 当Activity从一种状态转变到另一种状态时，会调用以下保护方法来通知这种变化： void onCreate(Bundle savedInstanceState) void onStart() void onRestart() void onResume() void onPause() void onStop() void onDestroy() 这七个方法定义了Activity的完整生命周期。实现这些方法可以帮助我们监视其中的三个嵌套生命周期循环： Activity的完整生命周期自第一次调用onCreate()开始，直至调用onDestroy()为止。Activity 在onCreate()中设置所有“全局”状态以完成初始化，而在onDestroy()中释放所有系统资源。例如，如果Activity有一个线程在后台运行从网络下载数据，它会在onCreate()创建线程，而在onDestroy()销毁线程。 Activity的可视生命周期自onStart()调用开始直到相应的onStop()调用结束。在此期间，用户可以在屏幕上看到Activity，尽管它也许并不是位于前台或者也不与用户进行交互。在这两个方法之间，我们可以保留用来向用户显示这个Activity所需的资源。例如，当用户不再看见我们显示的内容时，我们可以在onStart()中注册一个BroadcastReceiver来监控会影响UI的变化，而在onStop()中来注消。onStart() 和onStop() 方法可以随着应用程序是否为用户可见而被多次调用。 Activity的前台生命周期自onResume()调用起，至相应的onPause()调用为止。在此期间，Activity位于前台最上面并与用户进行交互。Activity会经常在暂停和恢复之间进行状态转换——例如当设备转入休眠状态或者有新的Activity启动时，将调用onPause() 方法。当 page的用法总结大全 page这个单词你知道是什么意思吗?page的用法是怎样的呢，快来了解一下吧，今天小编给大家带来了page的用法 ,希望能够帮助到大家，一起来学习吧。 page的意思 n. 页,(计算机的)页面,年史, vt. 标记…的页数,翻页,喊出名字以寻找,(在公共传呼系统上)呼叫 vi. 翻书页,浏览 变形：过去式: paged; 现在分词：paging; page用法 page可以用作名词 page的基本意思是“页”,指书刊、杂志等的一页或报纸等的一版,也可指纸的一张,还可指报纸的“专页”。 page也可指可写入书中的历史事件或时期。 page用作动词的意思是“标记…的页数”或“翻页”。 page用作名词的用法例句 There are several faults in the page of figures.那一页的数字中有几个差错。 Open your German readers at page 28.把德语课本翻到第28页。 The page number is shown at the foot of the page.在页脚处可以看到页码。 page可以用作动词 page用作动词的意思是“标记…的页数”或“翻页”。 page也可作“呼叫…”解,指在公共场所通过扩音器呼喊找人。 page是及物动词,接名词或代词作宾语。 page用作动词的用法例句 When the book is ready for printing,someone has to page it up.书在付印前，必须有人排好页码。 He tore the sheet in his hurry to turn over the page.他匆忙翻页的时候，把杂志都撕坏了。 Absorbed, she licked her index finger absently each time she turned a page.她读得出神，每次翻页就不自觉地舔一下食指。 实验二Activity组件的生命周期 一、实验目的 1.了解Activity组件的生命周期； 2.了解Activity组件的运行状态； 3.掌握Activity事件回调函数的作用和调用关系。 二、Activity相关知识 Activity是Android组件中最基本也是最为常见用的四大组件之一（Activity，Service服务,Content Provider内容提供者，BroadcastReceiver广播接收器）。Activity中所有操作都与用户密切相关，是一个负责与用户交互的组件，可以通过setContentView(View)来显示指定控件。在一个android应用中，一个Activity 通常就是一个单独的屏幕，它上面可以显示一些控件也可以监听并处理用户的事件做出响应。Activity之间通过Intent进行通信。 在android 中，Activity 拥有四种基本状态： 1、Active/Runing 一个新Activity 启动入栈后，它显示在屏幕最前端，处理是处于栈的最顶端（Activity栈顶），此时它处于可见并可和用户交互的激活状态,叫做活动状态或者运行状态（active or running）。 2、Paused 当Activity失去焦点，被一个新的非全屏的Activity 或者一个透明的Activity 被放置在栈顶，此时的状态叫做暂停状态（Paused）。此时它依然与窗口管理器保持连接，Activity依然保持活力（保持所有的状态，成员信息，和窗口管理器保持连接），但是在系统内存极端低下的时候将被强行终止掉。所以它仍然可见，但已经失去了焦点故不可与用户进行交互。 3、Stoped 如果一个Activity被另外的Activity完全覆盖掉，叫做停止状态（Stopped）。它依然保持所有状态和成员信息，但是它不再可见，所以它的窗口被隐藏，当系统内存需要被用在其他地方的时候，Stopped的Activity将被强行终止掉。 4、Killed 如果一个Activity是Paused或者Stopped状态，系统可以将该Activity从内存中删除，Android系统采用两种方式进行删除，要么要求该Activity结束，要么直接终止它的进程。当该Activity再次显示给用户时，它必须重新开始和重置前面的状态。 状态转换 当一个Activity 实例被创建、销毁或者启动另外一个Activity 时，它在这四种状态之间进行转换，这种转换的发生依赖于用户程序的动作。图2.1说明了Activity 在不同状态间转换的时机和条件： 9 如何使用网络分析仪 德力网络分析仪NA7682A NA7682A矢量网络分析仪吸取了前几代和国内外各款网络分析仪使用的经验，结合了最新国际仪器发展的技术和态势，是Deviser德力仪器最新推出的第四代矢量网络分析仪,作为国内主流的网络分析仪,下面介绍网络分析仪的使用技巧如下。 频率范围从100kHz到8.5GHz频段，为无线通信、广播电视、汽车电子、半导体和医疗器件等行业射频器件、组件的研发和生产的使用提供了高效、灵活的测试手段，进入了民品、工业、科研教育和军工等领域。其主要的特点是和主流网络分析仪是德的E507X系列指标和指令上做到兼容，在客户使用的性价比上非常优秀的选择。 在射频器件、基站天线、手机天线、GPS天线等、通信系统模块分析等领域成功的测试经验使越来越多的客户开始使用这款网络分析仪，在低频、800/900M、1800/1900M、2100M、5G/5.8G等的产品频率使用领域内广泛使用。 深圳市良源通科技有限公司专业服务和销售射频和通信仪表多年，是德力仪器国内最重要的合作伙伴和一级代理商，结合自己多年的技术积累和客户使用的配合测试，得到丰富经验。在仪器的售前和售后服务上面具有自己的优势。提供大量仪器试用和使用方案的设计，给客户在设备开发、产品研制和批量生产上都提供方便和最有优势的选择。 产品特点： 1、12.1英寸1280*800 TFT触摸屏 2、频率覆盖范围: 100 kHz 至 8.5 GHz 3、阻抗：50Ω 4、动态范围: >125 dB （比E5071C宽7-12dB) 5、极低的迹线噪声: <0.005 dBrms (在 3 kHz IFBW) 6、快速的测量速度: 80usec/点 7、分析和误差修正和校准功能 8、通过USB、LAN 和 GPIB 接口进行系统互联 9、时域分析（选件）：时域传输、反射特性分析；距离上的故障定位。 10、数据变换：涉及多种形式的阻抗、导纳变换。 11、滤波器分析：自动分析出：插损、3dB带宽、6dB带宽、带内纹波、带外抑制、Q值、矩形系数 实验6深入理解Activity 一、实验目的 1、掌握Activity的开发、配置和使用。 2、了解Activity的生命周期。 二、实验步骤 1、使用Bundle在Activity之间交换数据，运行的效果如下所示。 图1 第1个Actvity界面图2 通过第1个Actvity启动第2个Activity 要求与注意事项： 1、Activity01.java源代码所对应的布局文件main.xml文件，请参考图1自己编写。 2、OtherActivity.java源代码所对应的布局文件other.xml文件，请参考图2自己编写。 3、注意在AndroidManifest.xml文件中配置两个Activity。 第一个Activity的代码,即com.whq.Activity01.java，请补充所缺代码，给代码添加注释。 package com.whq; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; public class Activity01 extends Activity { private Button myButton = null; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(https://www.wendangku.net/doc/a7524889.html,yout.main); myButton = (Button) findViewById(R.id.myButton); myButton.setOnClickListener(new MyButtonListener()); } class MyButtonListener implements OnClickListener { @Override public void onClick(View v) { // 生成一个Intent对象 Intent intent = new Intent(Activity01.this,OtherActivity.class); startActivity(intent); } } } 第2个Activity的代码 package com.whq; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.widget.TextView; public class OtherActivity extends Activity{ private TextView myTextView = null; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(https://www.wendangku.net/doc/a7524889.html,yout.other); //取得从上一个Activity当中传递过来的Intent对象 Intent intent = getIntent(); //从Intent当中根据key取得value String value = intent.getStringExtra("testIntent"); //根据控件的ID得到响应的控件对象 myTextView = (TextView)findViewById(R.id.myTextView); //为控件设置Text值 Seated的用法小结 seated是一个比较特别的过去分词，说它特殊一是因为它的词性尚有不确定性——它有时是过去分词，有时又具有形容词的性质，像是一个形容词；二是因为这样一个很少引人注意的过去分词，在近几年的高考英语考题中经常“露脸”，一下子变成了一个热点词汇。下面我们先来看几道高考题： 1. Please remain __________ until the plane has come to a complete stop. (山东卷) A. to seat B. to be seated C. seating D. seated 2. Please remain __________; the winner of the prize will be announced soon. (辽宁卷) A. seating B. seated C. to seat D. to be seated 3. Can those _________ at the back of the classroom hear me? (福建卷) A. seat B. sit C. seated D. sat 对于seated的用法，首先要从动词seat说起。 同学们可能只知道seat的名词用法，即只知道它表示“座位”。 其实，seat还可用作动词，且是一个典型的及物动词，其意为“给某人座位”“让人坐”或“能容纳……”句式：sb be seated 或seat sb / oneself 。 如： Seat the boy next to his brother. 让那个孩子坐在他哥哥旁边。 We can seat 300 in the auditorium. 我们这个礼堂可容纳300人。 Android生命周期详解 在Android 中，多数情况下每个程序都是在各自独立的Linux 进程中运行的。当一个程序或其某些部分被请求时，它的进程就“出生”了；当这个程序没有必要再运行下去且系统需要回收这个进程的内存用于其他程序时，这个进程就“死亡”了。可以看出，Android 程序的生命周期是由系统控制而非程序自身直接控制。这和我们编写桌面应用程序时的思维有一些不同，一个桌面应用程序的进程也是在其他进程或用户请求时被创建，但是往往是在程序自身收到关闭请求后执行一个特定的动作（比如从main 函数中return）而导致进程结束的。要想做好某种类型的程序或者某种平台下的程序的开发，最关键的就是要弄清楚这种类型的程序或整个平台下的程序的一般工作模式并熟记在心。在Android 中，程序的生命周期控制就是属于这个范畴——我的个人理解:) 在Android 系统中，当某个activity调用startActivity(myIntent) 时，系统会在所有已经安装的程序中寻找其intent filter 和myIntent 最匹配的一个activity，启动这个进程，并把这个intent 通知给这个activity。这就是一个程序的“生”。比如我们在Home application 中选择“Web browser”，系统会根据这个intent 找到并启动Web browser 程序，显示Web browser 的一个activity 供我们浏览网页（这个启动过程有点类似我们在在个人电脑上双击桌面上的一个图标，启动某个应用程序）。在Android 中，所有的应用程序“生来就是平等的”，所以不光Android 的核心程序甚至第三方程序也可以发出一个intent 来启动另外一个程序中的一个activity。Android 的这种设计非常有利于“程序部件”的重用。 1测控系统简介 本测控系统专为拉力机、压力机、电子万能材料试验机而研制。适用于测定各种材料在拉伸、压缩、弯曲、剪切、撕裂、剥离、穿刺等状态下的力学性能及有关物理参数。可做拉伸、压缩、三点抗弯、四点抗弯、剪切、撕裂、剥离、成品鞋穿刺、纸箱持压、泡棉循环压缩、弹簧拉压及各种动静态循环测试。 1.1主要功能特性 1. 硬件 主控制器采用21世纪最先进的32位ARM处理器, 处理速度达到奔腾级通用计算机的水平,相比传统的8位单片机测控系统整体性能大大提高,运算速度更快,控制精度更高. 数据采集核心器件采用美国最新型超高精度24位AD，采样速率可达2000次/秒,可捕捉到力量的瞬间变化过程,全程不分档分辨力最高达500000分度。并采用独创的6点校准技术进一步提高精度，力量测量精度优于国家0.5级(最高级)标准。 位移编码器计数采用4倍频技术,使位移分辨力提高4倍,最高可达0.0005mm。 脉冲和电压两种输出控制方式，可控制具有脉冲或电压控制接口的任意伺服马达、变频马达或直流马达实现平滑无级调速，另还有上升、下降及停止等开关量信号输出可用于直接驱动外部继电器或电磁阀，可用于控制直流电机或气动、液压等动力装置。 先进的速度、位移、力量三闭环技术，可以实现精确的任意波形控制。 丰富的接口扩展能力：多达4路24位模拟量输入，3路16位模拟量输出，3路脉冲输出，3路AB相光电编码器输入，9路开关量输入，8路开关量输出，1路USB接口，1路RS232接口，1路RS485接口，4种LCD接口，1个并口微型打印机接口，1个串口微型打印机接口，1个8×4矩阵键盘接口。 所有输入输出接口均采用高速光电隔离技术，具备强大的抗干扰能力。 2. 软件 Windows标准风格，层次分明的操作方式加上详尽的帮助文档和提示使之成为目前试验机行业最简单易用的软件，您的调试和软件培训效率将显著提高。 采用多线程并行处理技术，测试过程中实时同时显示力量-位移、力量-时间、位移-时间、应力-应变等曲线，可随意切换到想看的曲线画面，并可查看用户设置等。 标准化的测试过程控制和报表输出模版，使可以定义任意多个测试标准供用户调用，范围涵盖GB、ASTM、DIN、JIS、BS…等几乎所有测试标准。灵活强大的测试方法自定义方式,具备定速速、定位移、定力量、定力量速率、定应力、定应力速率、定应变、定应变速率等各种控制模式，可实现复杂的多步嵌套循环控制.可设置自动返回、自动判断断裂、自动归零等功能。 强大的数据分析统计和曲线图形分析辅助工具，具备放大、缩小、平移、十字光标、取点等功能。多次历史测试数据可调入图形同时显示做对比分析。多达7个区间设置、40个手动取点、120个自动取点功能。具备最大值、最小值、平均值、去高低平均值、中位数、标准差、总体标准差、CPK值等多种统计功能。 完全开放的测试结果编辑方法，用户可得到任何想要的测试结果。最大力、断裂力、剥离力、拉伸强度、剪切强度、撕裂强度、最大变形、屈服力、伸长率、弹性模量、环刚度、非比例延伸率、区间最小力、区间平均力、定伸长取力、定力量取伸长等多达400多个计算结果均由计算机自动算出，供用户选择调用。 业界创新的Microsoft Word报表格式，简单易用，只要您会使用Word，就可编辑出您想要的精美报表。 权限管理系统使您可以锁定软件的任意功能模块,将软件操作分为多个权限级别,没被授权的操作人员无法触及没被授权的模块,软件操作更加安全可靠。 全数字化的校准系统，校准过程简单高效，校准数据上下位机双重保护。 功能强大的单位系统，可以适应世界上任何单位制，如力值单位有gf、kgf、N、kN、tf、lbf、ozf、tf（SI）、tf （long）、tf（short）等供选择,更可扩展任意多种单位。 更多重的保护机制：力量、行程、位移超量程保护设定，上下限位行程开关硬件保护设定。 测试数据管理简单直观高效：单次测试数据以Windows标准的文档形式存储，自由设置储存路径和文件名。避免了传统测控软件以数据库格式储存测试数据时数据库文件会越来越大而导致软件运行越来越慢的缺点。只要您的硬盘足够大，测试数据可以无限量保存。 所有操作均具有快捷键,并可连接外部手动控制盒,可外接快上、快下、中上、中下、慢上、慢下、置零、回位、测试、暂停、结束等全部常用按健. 多国语言一键切换：简体中文、繁体中文、英文，十国语言版更有日文、韩文、俄文、德语、法语、西班牙文、葡萄牙文等即将推出。 绿色软件，无需安装，直接拷贝到计算机即可使用（需先安装串口驱动）,维护升级更加简单。 Activity生命周期解说 二、事件方法链 2.1进入Activity onCreate -> onStart -> onResume 2.2BACK键 onPause->onStop->onDestroy 2.3HOME键 Home键退出：onPause->onStop Home键回来：onRestart -> onStart->onResume 2.4休眠/恢复 休眠：onPause 恢复：onResume 2.5旋转屏幕 未设置android:configChanges： onPause -> onStop -> onDestory -> onCreate -> onStart -> onResume 设置了android:configChanges="orientation|keyboardHidden"： 不会触发生命周期方法，参见文章这里。 2.6来电 来电，显示来电界面： onPause -> onStop 关闭电话界面，重新回到当前Activity： onRestart -> onStart->onResume 2.7其他Activity 进入下一个Activity： onPause -> onStop 从其他Activity返回至当前Acitivity： onRestart -> onStart->onResume 三、与Activity生命周期结合的应用场景 3.1与广播(Broadcast)结合 在onResume注册广播(registerLinstener)，在onPause注销广播(unregisterLinstener)。例如： 做"摇一摇"功能（传感器）、监听网络变化，就可以在onResume中注册监听，在onPause里注销掉，已节省资源提高效率。 3.2与服务(Service)结合 在onStart绑定服务(bindService)，在onStop中取消绑定(unbindService)。例如： confident的详细用法总结大全 你知道confident的用法吗?快来一起学习吧，下面就和大家分享，来欣赏一下吧。 confident的用法总结大全 confident的意思 adj. 确信的，深信的;有信心的，沉着的;大胆的，过分自信的;厚颜无耻的 n. 知己;心腹朋友; confident的用法 用作形容词(adj.) 用作定语 ～+n. We need a confident leader to overcome these difficulties. 我们需要一个有信心的领导者来克服这些困难。 He noticed her confident smile. 他注意到她充满自信的微笑。 用作表语 S+be+～+prep.-phrase I feel confident about the future of rock-and-roll music in China. 我对摇滚乐在中国的前景充满信心。 I am confident in him. 我对他充满信心。 He is confident in his ability to achieve success. 他坚信自己有能力取得成功。 We are confident in saying that the new record will be broken soon. 我们充满信心地说新的纪录很快会被打破。 S+be+～+that-clause I feel confident that we will win. 我确信我们将胜利。 confident的用法例句 1. He was confident the allies would make good on their pledges. 他相信盟友们会履行他们的承诺。 2. She has now changed into a happy, self-confident woman. 如今她已经变成一个快乐、自信的女人。 3. If there has to be a replay we are confident of victory. 如果重新比赛，我们有信心取得胜利。 4. Management is confident about the way business is progressing. 管理层对业务发展的态势充满信心。 5. Hes very forward and confident and chats happily to other people. 他很自以为是，喜欢和别人攀谈。 6. Police say they are confident of catching the gunman. 警方说他们有信心抓住那个持枪歹徒。 on holiday 还是on holidays Android开发历程_3(Activity生命周期) Activity中有7个与生命周期有关的函数。其中onCreated()是activity第一次被启动时执行的，主要是初始化一些变量，onRestart()是当前activity重新被启动时调用的；绑定一些监听器等；onStart()是activity界面被显示出来的时候执行的；onResume()是当该activity与用户能进行交互时被执行；onPause()是另一个activity被启动，当前的activity就被暂停了，一般在该函数中执行保存当前的数据；onStop()表示另一个activity被启动完成时，当前activity对用户同时又完全不可见时才调用的；onDestroy()是退出当前activity时调用的，当然如果程序中调用finish()或者说android系统当前资源不够用时就会被调用。 当用多个activity在执行时，这时候android系统会自动将这些activity压入栈中并且总是显示最顶的那个activity，这个栈在android叫做task，但是这个栈只支持压入和弹出操作，不支持排序插入等操作。 Activity的7个生命周期函数中的onStop()函数被调用时是在其对应的activity被另外的activity完全遮挡的时候，如果只有部分遮挡，则不会被调用。部分遮挡一般是以消息activtiy的形式出现，这个只需在AndroidManifest.xml中将其对于的activity的主题设置theme中更改即可。 这7个周期函数，当系统资源不够时，其中onPause(),onStop(),onDestroy()是有可能被系统kill掉的，但其它4个是不会被kill掉。 参考资料为mars老师的资料。 官方给出关于这7个生命周期的图如下： 语法格式： site : 网址关键词 或者关键词site : 网址 注意事项： 1、site:后边跟的冒号必须是英文的“:”，中文的全角冒号“：”无用 2、url前不能带http:// 3、url后边不能带斜杠“/”，其实是哪里都不能带/ 4、url中不要用www，除非你有特别目的，用www会导致错过网站内的内容，因为很多网站的频道是没有www的,也就是二级域名。 其他说明： 1、关键词既可以在“site:”前，也可以在“site:”后，搜索结果是一样的，但是不管谁前谁后，关键词和“site:”之间必须空一格。 2、对于“site:”搜索，关键词一样可以是多个，多个关键词之间以空格隔开。 3、支持与其他复杂搜索语法混用，各语法和关键词之间空一格 4、除了网站，还可以搜索网站的频道，但仅限于不用“/”的。 5、一个网站可能有多种语言，所以选择“搜索所有网站”和“搜索中文(简体)网页”是有差别的 当然，如果指定的网站只有一种语言，怎么选择就都一样了 用途： 1、可用于限制网站类型，学术资料在edu、org中会更精练，政府相关的在gov中也许更容易找。 2、用了edu、org、net、gov之类的域名后缀，并不会搜索所有含这个后缀的网站。只会搜索以这个后缀结尾的网站，带cn、us、si等各国家和地区域名后缀的edu.jp、https://www.wendangku.net/doc/a7524889.html,、org.it 等是不搜的，所以你要另外搜 3、搜索某种语言或某个关键词在指定国家的网站。 4、有的网站没有提供站内搜索，或者它的信息结构混乱，内容又多，不好找东西，那么可以用“site:”对这个网站进行检索。 google的“site:”功能比多数网站自己的站内检索还要好用，如果你查的不是动态数据库，而且对时效性要求不高的话。 5、搜索不欢迎你搜索和免费使用的网站、数据库的部分内容。 6、用“site:”搜索死链接网站、已关闭网站内的信息。 一、测试仪表预调 选择测试天线的频率范围 （1）按ON/OFF按钮打开SiteMaster。 （2）按MODE键。测量模式选择频率-驻波比域,然后按F1 软键。输入天线系统的下限（“Lower”）频率MHz值，按ENTER 键。 （3）再按F2 软键。输入天线系统的上限（“Higher”）频率MHz值，按ENTER键。在显示区域显示新的频率数值范围FREQ scale。检查是否与输入的频率范围一致。 二、测试仪表较准 （1）将测试口扩充电缆（the test port extension cable）连到测试端口。若在扩充电缆端口校准，则测出的天馈线长度以此点为参考点。若在标准测试端口校准，则测出的天馈线长度以点为参考点。 （2）接校准器，按START CAL 键，开始校准。 三、输入天馈线的参数 （1）按MODE 键。选择故障定位-驻波比菜单。 （2）按DTF帮助软键。 （3）按电缆损耗(LOSS)菜单。 输入要测试的天馈线类型的每米的损耗dB值(7/8硬馈线，型号为LDF5-50A，cable loss=0.043dbm/m；1/2的软跳线，型号为LDF4-50A，cable loss=0.077dbm/m) ，然后按ENTER. 注意: 只有采用供货商提供的正确值，才能保证测试结果的可靠性。 （4）再按传播速率PROP V 菜单。输入relative velocity (7/8硬馈线，型号为LDF5-50A，Vf=0.89； 1/2的软跳线，型号为LDF4-50A，Vf=0.88)，然后按ENTER键。 注意：也可调出电缆表，直接选中所用的电缆型号。若有几种电缆混用，则选择使用最长的电缆型号。可省略（3）（4）两步。 （5）按ENTER键返回主菜单。 Android Activity生命周期解析 摘要：Android（安致）操作系统应用包括四个部分：Activity活动，Intent Reciver，service和Content provider。其中，一个activity是应用中的一个单一的屏幕，它继承自Activity类，它将显示由Views组成的UI以及响应事件。 关键词：Android；Activity；生命周期 中图分类号：TP311.52 文献标识码：A文章编号：1007-9599 (2011) 10-0000-01 Android Activity Life Cycle Analysis Li Jiajun (China University of Mining&Technology Resources Institute,Xuzhou221000,China) Abstract:Android operating system applications include four parts:Activity activity,Intent Reciver,service,and Content provider.Among them,an activity is the application of a single screen,it inherits from the Activity class,it will show the composition of the Views UI,and respond to events. Keywords:Android;Activity;Life cycle Android（安致）底层以Linux内核工作为基础， 个人学法用法情况总结 我镇20××年普法依法治理工作在镇党委统一领导下,认真践行"三个代表"重要思想,围绕社会稳定、经济发展开展各项工作,为构建平安和谐先市营造了良好的法制环境。现将今年以来我的学法用法情况报告如下: 一、加强领导,健全制度,确保依法治镇工作顺利进行。一是调整充实了真法建办成员,完善了矛盾调处中心建设,制定和健全了矛盾纠纷排岔调处制、党委中心组学习学法制度、干部职工学习学法制度、普法依法治理工作宣传教育和普法依法治理工作责任制度等。二是年初根据工作实际,及时制?1?7?1?7了《法制宣传教育和普法依法治理工作意见》,10 月份又研究制定了《全民法制宣传教育的第五个五年规划》,使学法用法工作有安排,有措施,做到了有条不紊地进行。三是落实责任,明确目标。年初与各村(社区)各单位签订目标责任书落实责任,政府机关各办所及职能部门制定出依法行政、公正执法、争创平安办所计划,并通过验收合格。二、认真总结经验教训,切实开展形势多样的宣传活动。一是推广"四五"普法工作中全民学法的经验,召开现场推广会,把后坝、庙高村的经验予以推广。http:///3221788 (使用请双击此处删除页眉文字) 专业好文档为您倾心整理,谢谢使用二是及时表彰在普法依法治理工作涌现的先进单位和个人,有4 个村(社区) 单位和6 个个人获得表彰。三是充分利用三月法制宣 传月、"6.26"禁毒日、"12.4"法治宣传日、流行性传染病防治等重要日期开展多种形式的法制宣传教育。据不完全统计,宣传活动中散发宣传资料2 万多份,上街设点咨询4 次,接受群众咨询80 多次,有力地宣传了法律法规和党在农村的各项政策。四是认真搞好青少年学生的法制教育,落实了师资、教材、课时、计划,并组织法制副校长、关工委负责人等到校上法制课4 次,使3000 多学生普遍接受到了法制林剑教育。五是组织开展了"一日助贫"和向受灾户送暖和活动,机关职工、村社区干部、单位职工等140 多人次参与,捐款捐物折合人民币8000 多元。三、不断推进依法治理工作。政府继续聘请常年法律顾问,做好规范性文件清理。坚持按季度公开政务、财?1?7?1?7、村务,将依法治村(社区)、治企、校列入工作议事日程。认真开展打击两抢一盗、禁毒、非法生产烟花爆竹、乙脑防治、森林火灾防治等专项治理活动。加强部门之间的配合协作,清理整顿教育、卫生、城建、网吧等违法经营行为。按时排查调处各类矛盾纠纷,维护社会稳定。全年共排查调处纠纷公文写作首选网站-- 公文网74 件,成功71 件,调处率100,成功率96。四、努力做好信息收集上报工作。http:///3221788 (使用请双击此处删除页眉文字) 专业好文档为您倾心整理,谢谢使用鼓励干部职工群众积极收集上报信息,综治办、司法所等写出"四 Service 的生命周期回调函数 和Activity 一样，service 也有一系列的生命周期回调函数，你可以实现它们来监测service 状态的变化，并且在适当的时候执行适当的工作。 Like an activity, a service has lifecycle callback methods that you can implement to monitor changes in the service's state and perform work at the appropriate times. The following skeleton service demonstrates each of the lifecycle methods: 13 下面的service展示了每一个生命周期的方法： 【文件1-5】Service生命周期回调函数 1.public class TestService extends Service { 2.int mStartMode; //indicates how to behave if the service is killed 3.IBinder mBinder;// interface for clients that bind 4.boolean mAllowRebind;// indicates whether onRebind should be used 5. 6.@Override 7.public void onCreate() { 8.// The service is being created 9.} 10. 11.@Override 12.public int onStartCommand(Intent intent, int flags,int startId){ 13.// The service is starting, due to a call to startService() 14.return mStartMode; 15.} 16. 17.@Override 18.public IBinder onBind(Intent intent) { 19.// A client is binding to the service with bindService() 20.return mBinder; 21.} 22. 23.@Override 24.public boolean onUnbind(Intent intent) { 25.// All clients have unbound with unbindService() 26.return mAllowRebind; 27.} 28. 29.@Override 30.public void onRebind(Intent intent){ 31.// A client is binding to the service with bindService(), 32.// after onUnbind() has already been called 33.} 34. 35.@Override 36.public void onDestroy(){ 37.// The service is no longer used and is being destroyed 38.} 39.} 注意：不同于Activity的生命周期回调方法，Service不须调用父类的生命周期回调方法。 Unlike the activity lifecycle callback methods,you are not required to call the superclass implementation of these callback methods. 14 face的用法精析小结 你知道face的用法吗?快来一起学习吧，下面就和大家分享，来欣赏一下吧。 面对面：face的用法精析 The significant problems we face cannot be solved at the same level of thinking we were at when we created them. ——Albert Einstein 面对问题时，我们不能用制造它们时同一水平的思维来解决它们。 ——阿尔伯特·爱因斯坦 一、下面我们来看看face有几种含义 n. 1.脸，面孔;面容，面部表情the front part of the head between the forehead and the chin She has a lovely oval face. 她长着一张可爱的椭圆脸。 2.外表，外貌facial expression A fair face is half a portion. 美貌等于一半嫁妆。 3.表面，正面outward appearance The sea have erode the cliff face over the years. 海水经年累月冲刷着峭壁的表面。 4.面子，威严assurance, confidence To cancel the airport would mean a loss of face for the present governor. 撤销机场对现任州长来说将是件丢脸的事情。 5.有…面容的;有…表情的a facial expression of distaste or displeasure He came to me with a very long face. 他拉长了脸来找我。 6.钟面;表盘a front, upper, or outer surfaceActivity生命周期详解
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