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XML-based representation in a CBR system for fixture

339 XML-based Representation in a CBR System for Fixture Design

Fan Liqing1 and A. Senthil Kumar2

1National University of Singapore, mpeflq@https://www.wendangku.net/doc/3f14408816.html,.sg

2National University of Singapore, mpeask@https://www.wendangku.net/doc/3f14408816.html,.sg

ABSTRACT

Fixture design is a complex process and largely relies on a designer's experience to solve current

problem. Case-Based Reasoning (CBR) provides a promising methodology for solving design

problems in this complex domain based on the idea that past problem-solving experiences can be

reused and learned from in solving new problems. In order to realize a CBR design system to assist

designers to solve fixture design problems in the Internet-enabled environment, case representation

is described using XML (eXtensible Markup Language) format in this paper. The XML-based

representation structure using UML (Unified Modeling Language) notation is illustrated and

discussed. A design process with an example is presented in the developed system applied with

XML-based representation. The Internet-enabled CBR system for fixture design is developed and

implemented in client-server mode architecture.

Keywords: Case-based reasoning, fixture design, case representation, XML, UML.

1. INTRODUCTION

Fixtures are devices which are designed to repeatedly and consistently maintain the orientation of a workpiece during machining, assembling, welding, inspection, etc. [1]. They are an essential part of manufacturing production. As part of manufacturing tooling, fixture design makes significant contributions to the production time and cost in daily production. Flexible fixtures play important roles in modern flexible manufacturing systems (FMS) as well as computer-integrated manufacturing system (CIMS).

Fixture design is a highly complex process because it must consider the workpiece, the cutting tools and the machining environment. In addition to these aspects mentioned above, Senthil Kumar et. al. [2] illustrated all factors considered in fixture design that are categorized into three basic constraints, including technical, economical and resource availability.

Fixture design is also experience-based. Designers prefer to use previous designs because they save time and effort and use the concepts have proven effective in previous situations. In the design of fixture, based on all the information pertinent to the product as given by the engineering specification and the process sheet, a tool designer configures a fixture setup appropriate to the workpiece depending on his/her experience of fixturing a similar product [3]. Meanwhile, the selection of surfaces on the workpiece and fixture elements for locating and clamping during machining is flexible and largely relies on the prior experience of the designer.

In today's product development context, the design of products is sub-contracted out to other firms. This creates a scenario where the designers and manufacturing engineers may be globally dispersed. Implementing distributed manufacturing systems would offer rapid manufacturing capacity. An Internet-enabled manufacturing system which has the ability to cooperatively design not only saves costs and time, but also creates a seamless collaborative manufacturing environment to resolve problems in real-time. Therefore, to realize a collaborative functional fixture design system, care must be taken such that the design activity can be performed on the internet.

For these reasons, a case-based reasoning (CBR) approach which organizes previous experiences as cases to solve new problem is attempted in this work. Except CBR approach, a new paradigm in Computer Integrated Manufacturing (CIM), namely Internet-based Manufacturing, is also adopted in this work. The objective of this research is to develope a system where design of fixture is done in case-based reasoning environment over the Internet.

Computer-Aided Design & Applications, Vol. 2, Nos. 1-4, 2005, pp 339-348

340

Case-based reasoning (CBR) is an artificial intelligence technique which is a general problem solving method using past experiences to solve novel problem [4]. The major consideration in a case-based reasoning approach to design is as following:

Representation of design cases;

Indexing and retrieving similar cases from case-base;

Adapting the retrieved cases for current design.

Case representation is generally regarded as one of the most important issues and is crucial to success of case-based reasoning system. In this distributed fixture design system, case representation is concerned with two areas of research. First, as a fundamental aspect of the CBR paradigm, case is not only described as problem, solution and outcome in fixture design domain, but also represented in a manner that allows efficient retrieval, easy maintenance and transmission over network. Second, a case representation can be devised as an open standard in fixture design domain and exchange information with other computer-aided manufacturing systems.

Although Case-Based Reasoning is a knowledge-rich methodology, there is no standard means of representing the case in a case base. CASUEL, a Common Case Representation language, is developed in the INRECA project [5]. CASUEL is a flexible, object-oriented frame-like language for storing and exchanging descriptive models and case libraries in ASCII files. M. Marefat and J. Britanik [6] present an object-oriented model representation in case-based process planning for 3D prismatic parts. The model consists of the feature-based part information model, the process plan information model and tools knowledge concerned with process plan. These two are only developed on local computer but not over network. Hayes et. al. [7] have developed an XML-based Case Mark-Up Language (CBML) for e-commerce through Internet. This language allows user to make the formal definition of the structure of our cases completely independent of the application code. CBML also makes system for industry extensibility, easy of reuse and interoperability. Although CBML supports complex case representation, such as hierarchical cases and object-oriented cases, as well as the commonly used flat vector format, it does not suit for Internet-based CAD applications in which sometimes a large amount data are required to transfer over the Internet.

In fixture design domain, vast amount of research works is reported on developing computer aided system. Various approaches have been attempted in fixture design, i.e. Rule-based expert system, Genetic Algorithm, Multi-agent Approach, Machine Learning, Geometric Analysis. Some have been integrated and hybrid systems have been developed. However, there is no information exchange between these systems and hence the fixture design output information can not be shared with other manufacturing domain. Jerard and Ryon [8] developed Numerical Control Markup Language (NCML) based on XML as data exchange format to permit buyers and sellers of custom machined parts to conduct e-commerce over the Internet. In this language, information regarding workpiece, setups, tools, and tolerance is provided to allow users to judge the manufacturability of a part. However, NCML does not provide any information about fixture.

This paper is primarily focused on representing XML-based fixture design cases using Unified Modeling Language (UML) [13] for the developing case-based reasoning system. XML is a description language that supports meta-data description for particular domains and these meta-descriptions allow applications to interpret data marked up according to this format. Besides being a recommendation of W3C, XML [12] is used in our work because it is neutral, platform-independent, and flexible and allows structured data in Web applications. This means we can collect data from various place and exchange structure rich data in various applications over existing network protocol. Today, there is also ongoing development that will include a query language in the XML standard. UML was chosen because it is a popular method for designing software and has proven to be valuable for data modeling [11].

2. XML-BASED REPRESENTATION USING UML

This section illustrated XML-based fixture design cases and modeling XML file represented in the UML. The graphical UML notations that are used to represent XML model are summarized in Fig. 1. The UML depicts a class as a rectangle with its name at the top and its attributes in the middle (Fig. 1a). Relationships between classes are depicted as lines that link them. The inheritance relationship is identified by a hollow triangle at the end of line that indicates the superclass (Fig. 1c), while the aggregation relationship is identified by a diamond at one end of line that indicates the owning class and by an arrow at the other end (Fig. 1b). Multiplicity indicates how many instances of one class are related to a single instance of another class at a given point in time. For example, Fig. 1c means one class whole has many parts. The multiplicity notations are located at the end of a link. The meaning of them is shown in Fig.1d.

Computer-Aided Design & Applications, Vol. 2, Nos. 1-4, 2005, pp 339-348

341

Class Name Attribute

Fig. 1 Unified modeling language notation

2.1 Case Structure

To identify the content of a design case, it is important to find out how design and design requirements are represented in practice. Requirements for a fixture are the workpiece to be fixtured, manufacturing resources and fixture elements provided. For modular fixture design, design outcomes are fixture planning that deals with overall design concepts and fixture layout that produces a spatial layout of the fixture. Therefore, the representation of a case in fixture design is divided into three parts: part representation, setup representation and fixture representation. A workpiece is described using feature-based geometry and material properties. The machining features are grouped according to their orientations and machining constrains into setups. In one setup, only one fixture is associated with it. By this way, the three parts are linked (Fig. 2). The setup information including manufacturing resources and fixture plan is usually provided by process planners who can access the system and co-operate with fixture designers, while fixture design which includes fixture layout and fixture configuration is final solution for the requirement.

2.2 Part Representation

Part design is the input to the fixture design system. In case representation, its role is similar to the problem description. It is represented not only as a part stored in case base but also as a new case to be solved. Part representation contains not only geometric shape but also material property.

The geometric information is composed of a set of features, their interactions, faces, points for clamping, locating and supporting, as well as engineering information (tolerance, dimensions, etc.) pertaining to the features. Feature class represents the complete machining area in a workpiece by showing the size and type of features present. The features include the following classes, i.e. boss, pocket, hole, slot, step, and each class can be classified further. Fig. 3 shows the part representation using UML notation.

Inheritance is exploited in representing the knowledge of the features. In Fig. 4, Feature class is an abstract class only acting as interface for basic shape feature classes, i.e. Hole, Slot, etc. These subclasses inherit the common attributes from Feature class and other features are created from basic shape features. For simplicity, subclasses of Tolerance class and basic feature shape classes are not displayed in Fig. 3. However, in order to clarify the inheritance, the Hole class and its subclasses are shown in Fig. 4. In Fig. 4, the classes in the third level refer to the implementation class; the classes in the first two levels are Meta-class. In the class “Hole”, the class “Couterbore Through Hole” is inherited from its super class “ThroughHole” which is inherited from metaclass “Hole”. The class “Counterbore Through Hole” not only includes its own attributes “CounterDiameter” and “CounterDepth”, but also inherited the attribute “Diameter” which represents the diameter of an inner hole from its super class “ThroughHole”.

(a) Class:

(b) Aggregation:

(d) Multiplicity of Association:

* 0 1 0..* 1..* 0..1 many zero one

zero or more (optional) one or more zero or one

342

Fig. 2. Case structure

Feature Name

Feature Name Feature Name Feature Name

Feature Name Feature Name

PartID : Integer

PartName : String

Material : String

Hardness

Shape Type

Machine Type

FaceID : Integer

Feature Name

FeatureID

Position

Normal

Fig. 3. Feature representation in UML notation

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343

ThroughHole Feature Type Diameter

BlindHole

Feature Type

Diameter

Depth Feature Name

SimpleThrough Hole FeatureSubType Counterbore Hole

FeatureSubType

CounterDiameter

CounterDepth

Countersink Hole

FeatureSubType

CounterDiameter

CounterDepth

SimpleBlind Hole

FeatureSubType

CounterDiameter

CounterDepth

Blind Countersink

FeatureSubType

CounterDiameter

CounterDepth Fig. 4. Inheritance in the Hole class

2.3 Fixture Design Representation

A case obviously includes the solution to the problem. In fixture design domain, the solution is usually a complete fixture layout configuration, which includes details on the work-piece, base plate, supporting surfaces, points and elements, locating surfaces, points and elements and clamping surfaces, points and elements. This information can be provided to fixture analysis and process planning. In the developing system, the focus is on modular fixture that inherits from fixture. The modular fixture is composed of fixture elements that can be mainly categorized into four functional units: Base plate, Locator, Support and Clamp class. Locating elements, supporting elements and clamping elements are located and assembled on a base plate through “LocatorPointID”, “SupportPointID” and “ClampPointID” respectively in a fixture. Accessory elements associated with the four functional units are assembled in a fixture if necessary. These fixture elements contact with workpiece through assembling Faces. The detailed fixture design representation is shown in Fig. 5.

2.4 Setup Representations

Set-up planning is one of the important issues in process planning and requires extensive experience. A set-up is defined as a task of determining a sequence of features and the number of set-ups required in fixturing configurations. Set-up planning information enables the consideration of the fixture design configuration, positioning locators, clamps and supports. Setup links the workpiece and its fixture designs together, and contains information that includes machining features in workpiece, workpiece orientation, fixture planning, support faces, locating faces, and clamping faces. One workpiece may require many set-ups, while each setup only requires one fixture (Fig. 6)

3.SYSTEM IMPLEMENTATION AND CASE STUDY

The developed system together with the representation described above is implemented in three-tier client-server architecture and uses Java as the programming language, Java3D as the graphics API and XML as the information exchange file format so as to provide the flexibility of interoperability on a variety of operating platforms. The system consists of three main parts: the client, the server and the case library. The detailed implementation refers to [9].

Computer-Aided Design & Applications, Vol. 2, Nos. 1-4, 2005, pp 339-348

344 FixtureID

number of Fixture Location of Fixture Clamping Sequence

LocatorName LocatorID

LocatorPointID

SupportName SupportID

SupportPointID

Base Plate BaseplateName BaseplateID

ClampName ClampID

ClampPointID

PartName PartID

Type of Modular Fixtures

Material Stiffness Position Normal

As Workpiece WorkpieceID

FaceID : Integer

0..*

Fig. 5. Fixture Design Representation Model in UML Notation

FixtureID

FeatureID

workpiece ID workpiece name

SetupID

fixture planning support faces locating faces clamping faces

face ID : Integer normal

Fig. 6. Setups in UML notation

The server side consists of back-end CBR engine, Parasolid model kernel, server classes, data compression, and the Remote Method Invocation (RMI) interface. The back-end CBR engine includes case indexing and case retrieval module. When server side receives and processes the request from the client end, CBR engine searches and matches new case with cases in Case Library, retrieves desired candidates, and sends them back to original client. Current proposal is to perform CBR retrieval on the server-side, because case retrieval module including indexing, searching and matching cases in case library can be computationally intense process, especially for a huge case library. We do so in order to make high-end server to handle heavy computing.

345 The client application handles visualization, CBR front engine, RMI interface to server and XML parser. The front-end CBR engine is composed of case selection, case storage, and case adaptation & repair module. It is integrated with 3D solid modeling so that a user can visualize information from case-based reasoning via the models. Since a distributed CBR system could potentially have many clients connecting simultaneously, case retrieval is computationally intense process, and current PC performance at client-end is increasingly well, distributing as much work as possible to the client side could possibly speed up the reply time for all users on the network. Under these circumstances, the trend seems that the thin-clients are growing fatter or have the ability to put on the weight. So that, the front-end CBR engine is put in client-side.

Case library developed using Apache Xindice XML server [10] includes fixture design, workpiece feature information and manufacturing information which are in XML file format. The benefit of a native solution is that you do not have to worry about mapping your XML to some other data structure. You just insert the data as XML and retrieve it as XML. You also gain a lot of flexibility through the semi-structured nature of XML and the schema independent model used by Xindice.

The proposed system using CBR is also following certain sequential steps; hence the user can follow the design stage and interact with the system. The detailed work flow is shown in Fig. 7. The first three steps, new workpiece import, feature extraction and setup information setting, are considered as design-problem specification. The setup information may be provided by a process planner.

Fig. 8 shows a workpiece whose shape type is prismatic is loaded in the system and the machining features are extracted. The feature information is shown in XML file. We can know the part name is “model3” from tag and part id is 32 from tag. The feature information is provided in the tag. Fig. 8 also shows Slot class, its subclass and its attributes in the tag.

Fig. 9 shows XML schema for the imported workpiece setup information. The XML file may be retrieved and displayed on the Internet Browser. For this workpiece, only one setup is applicable; we can know that the setup ID is “101” from tag, the fixture planning is “3-2-1” from tag, and the machine type for manufacturing operation “Mill, Drill” is “Vertical Machine” from tag.

Client

Control Flow

Data Flow

XML/

HTTP

Fig. 7. Work flow of CBR on fixture design

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The process of case indexing and case retrieval including case similarity matching and ranking reside in server. The input part compares with the models in the case-base. The compared models are ranked based on the similarity values. The ranked cases are returned back to client and the fixture designs are displayed on the client for selection (Fig. 10). A desired design can be chosen from ranked list for adaptation. After the selected design case is adapted, the new design case shown in Fig.11 is directly stored to the case library in case storage process.

Fig. 11 shows the complete fixture design and its corresponding XML file describing the detailed fixture design. From tag, we can know the workpiece name is model4. The locator information is in the tag. The name of one of the locators in the fixture design is BJ400-12050 and its associated face ID with workpiece is 267.

4. CONCLUSION

Case representation is one of the most important research issues in developing case-based reasoning system. This paper mainly discusses the case representation in XML format in the Internet environment. XML-based representation developed in fixture design domain is illustrated in the aspect of part representation, setup representation, and fixture design representation using UML notation respectively. Through the case representation, the new problem and the solution in the area of fixture design are described in XML schema. One reason XML schema is adopted to represent case is that it can facilitate network transmission, case retrieval and case storage over the Internet. Another reason is that it can be regarded as open standard to exchange manufacturing information with other CAD/CAM systems. Based on this XML-based representation, the distributed CBR system for fixture design is implemented and developed.

5. REFERENCES

[1]Nee, A.Y.C., Whybrew, K. and Senthil Kumar A. (1995). Advanced fixture design for FMS,Springer-Verlag,

c1995.

[2]Senthil Kumar, A. and Nee, A.Y.C. (1995), “A framework for a variant fixture design system using case-based

reasoning technique”, Manufacturing Science and Engineering; ASME, MED, Vol. 2-1, pp. 763-775.

[3]Nnaji, B.O. ; Lyu, P. (1990), Rules for an expert fixturing system on a CAD screen using flexible fixtures,

Journal of Intelligent Manufacturing, Volume 1, Issue 1, 1990, Pages 31-48

[4]Kolodner, J. L. (1993). Case-Based Reasoning. Morgan Kaufmann.

[5]INRECA consortium (1994). “CASUEL: A Common Case Representation Language”, at

https://www.wendangku.net/doc/3f14408816.html,rmatik.uni-kl.de/~bergmann/casuel/

[6]Marefat, M.; and J. Britanik. (1997), Case-based process planning using an object-oriented model

representation, Robotics & Computer-Integrated Manufacturing 13(3):229-251.

[7]Hayes, C. & Cunningham, P. (1999) Shaping a CBR View with XML. Proceedings of the Third International

Conference on Case-Based Reasoning, ICCBR’99, Seeon Monastery, Germany. LNCS Vol. 1650. Althoff, K.-

D., Bergmann, R.,Branting, L.K. (Eds.) Springer-Verlag Berlin/Heidelberg 1999, pp.468-481

[8]Robert B. Jerard and Okhyn Ryon, "NCML: A Data Exchange Format for Internet Based Machining," 2002

Japan USA Symposium on Flexible Automation (JUSFA), July 15-17, 2002 Hiroshima, Japan.

[9]Fan, L.Q.; A. Senthil Kumar and F. Mervyn; “The Development of a Distributed Case-Based Fixture Design

System”, 2004 Japan USA Symposium on Flexible Automation (JUSFA), July 19-21, 2004, Denver, Colorado, USA.

[10]Xindice, (2002), The Apache Software Foundation, at https://www.wendangku.net/doc/3f14408816.html,/xindice/

[11]David Carlson, (2001), Modeling XML applications with UML: practical e-business applications. Addison-

Wesley, c2001.

[12]https://www.wendangku.net/doc/3f14408816.html,/XML/

[13]https://www.wendangku.net/doc/3f14408816.html,/

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347

Fig. 8. Loaded workpiece and its feature XML schema

Fig. 9. XML schema for setup

- -

model3 32

Prismatic Cast Iron

Normalizing Vertical Machine + + . . .

- -

Slot

ThroughSlot

Rectangular -

0.03 0.015 + + + +

Slot

model3 32 -

101

3-2-1 Vertical Machine

Mill, Drill -

267

+ + +

+ +

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348

Fig. 10. The new workpiece and fixture designs of its similar parts

Fig. 11. The final fixture design of the new workpiece and its XML schema

model4

DWORKPIECENAME>

IECEID>

BJ010-4050-12

126

0.05

NESS> . . .

BJ400-12050 471

13 + -

32 -

267 +

Locator

高频电路原理与分析

. 高频电路原理与分析期末复习资料陈皓编 10级通信工程 2012年12月 1.

单调谐放大电路中，以LC并联谐振回路为负载，若谐振频率f0=10.7MH Z，C Σ = 50pF，BW0.7=150kH Z，求回路的电感L和Q e。如将通频带展宽为300kH Z，应在回路两端并接一个多大的电阻？解：（1）求L和Q e （H）= 4.43μH （2）电阻并联前回路的总电导为 47.1（μS）电阻并联后的总电导为 94.2（μS）因故并接的电阻为 2.图示为波段内调谐用的并联振荡回路，可变电容C的变化范围为12～260 pF，Ct为微调电容，要求此回路的调谐范围为535～1605 kHz，求回路电感L 和C t的值，并要求C的最大和最小值与波段的最低和最高频率对应。 12 min , 22(1210) 3 3 根据已知条件，可以得出：回路总电容为因此可以得到以下方程组 160510 t t C C C LC L C ππ ∑ - =+ ? ?== ? ?+ ? ?

题2图 3.在三级相同的单调谐放大器中，中心频率为465kH Z ，每个回路的Q e =40，试问总的通频带等于多少？如果要使总的通频带为10kH Z ，则允许最大的Q e 为多少？解：（1 ）总的通频带为 121212121232 260109 121082601091210260108 10198 1 253510260190.3175-12 6 1605 535 （）（）10103149423435 t t t t C C C C pF L mH π-----?+==?+=?-??-= ?==??+?=≈

2018年日本被动元件行业分析报告

2018年日本被动元件行业分析报告 2018年8月

目录一、被动元件景气周期持续 (5) 5 1、被动元件-电子产业的基石 ............................................................................... 2、下游应用驱动新一轮全球涨价潮 (6) （1）下游应用是推动被动元件涨价的主因 (7) （2）消费电子技术升级、5G 带来旺盛需求 (7) ①智能手机 (7) ②5G通信 (7) ③汽车电子使被动元件向高端化、精细化发展 (8) 二、日本被动元件的霸主之路 (9) 1、日本被动元件产业的崛起 (9) 2、电容市场竞争格局及日本厂商 (11) （1）陶瓷电容 (13) （2）村田制作所：被动元件世界霸主 (14) ①公司概况 (14) ②被动元件世界霸主 (15) ③陶瓷电容及MLCC (15) （3）薄膜电容 (17) （4）铝电解电容 (18) 3、电感市场竞争格局及日本厂商 (19) （1）电感市场竞争格局 (19) （2）太阳诱电：电感和电容双轮驱动 (20) ①公司概况 (20) ②创新发展，电感电容齐头并进 (21) ③“精细”与“极致”铸就优良品质 (22) ④产品结构调整，发力汽车电子领域 (22)

4、电阻市场竞争格局及日本厂商 (22) （1）电阻市场竞争格局 (22) （2）罗姆(ROHM)：工匠精神、专注主业 (24) ①公司概况 (24) ②工匠精神、专注深耕片式电阻 (25) 26 5、京瓷：电子陶瓷之王 ...................................................................................... （1）公司概况 (26) ①业务多点开花，业绩实现稳健增长 (26) ②精密陶瓷五十年的精进 (26) （2）京瓷的成功之道 (28) 三、借鉴日本，国产被动元件突围 (29) 29 1、国产被动元件自主可控 .................................................................................. 30 2、陶瓷电容：三环集团 ...................................................................................... 30 3、薄膜电容：法拉电子 ...................................................................................... 4、电感：顺络电子 .............................................................................................. 31 31 5、铝电解电容：艾华集团 ..................................................................................

2018年被动元件行业分析报告

2018年被动元件行业分析报告 2018年9月

目录 4 一、行业定义............................................................................................. 二、行业市场容量和变化趋势 (5) 6三、行业供需状况 .................................................................................... 8 1、电容 .................................................................................................................... 11 2、电阻 .................................................................................................................. 15 3、电感 .................................................................................................................. 四、行业主要技术经济特征 (19) 五、行业历史发展和技术变化 (20) 1、1935s~1980s：日系寡头最早切入抢占先机，依托创新和全球化布局巩固 21市场地位 ................................................................................................................ 2、1970s~2000s：美韩台各展所长，“一超多强”格局形成 (21) 3、21世纪至今：中国借助消费市场和政策东风成为新晋玩家 (22) 六、行业所处的生命周期阶段 (23) 七、行业经营周期性特征 (24) 八、行业主要公司简况 (25) 25 1、电容 .................................................................................................................. （1）火炬电子 (25) （2）宏达电子 (25) （3）法拉电子 (25) 26 2、电感 .................................................................................................................. （1）顺络电子 (26) 26 3、综合 ..................................................................................................................

高频电路原理与分析

高频电路原理与分析期末复习资料陈皓编 10级通信工程 2012年12月

1.单调谐放大电路中，以LC 并联谐振回路为负载，若谐振频率f 0 =10.7MH Z ， C Σ= 50pF ，BW 0.7=150kH Z ，求回路的电感L 和Q e 。如将通频带展宽为300kH Z ，应在回路两端并接一个多大的电阻？解：（1）求L 和Q e （H ）= 4.43μH （2）电阻并联前回路的总电导为 47.1（μS）电阻并联后的总电导为 94.2（μS）因故并接的电阻为 2.图示为波段内调谐用的并联振荡回路，可变电容 C 的变化范围为 12～260 pF ，Ct 为微调电容，要求此回路的调谐范围为 535～1605 kHz ，求回路电感L 和C t 的值，并要求C 的最大和最小值与波段的最低和最高频率对应。题2图 12min 12max ,22(1210) 22(26010)3 3根据已知条件，可以得出：回路总电容为因此可以得到以下方程组16051053510t t t C C C LC L C LC L C ππππ∑ --=+? ?== ??+?? ??== ??+?

3.在三级相同的单调谐放大器中，中心频率为465kH Z ，每个回路的Q e =40，试问总的通频带等于多少？如果要使总的通频带为10kH Z ，则允许最大的Q e 为多少？解：（1）总的通频带为 4650.51 5.928()40 e z e Q kH =≈?= （2）每个回路允许最大的Q e 为 4650.5123.710 e e Q =≈?= 4.图示为一电容抽头的并联振荡回路。谐振频率f 0 =1MHz ，C 1 =400 pf ，C 2= 100 pF 121212121232 260109 121082601091210260108 10198 1 253510260190.3175-12 6 1605 535 （）（）10103149423435 t t t t C C C C pF L mH π-----?+==?+=?-??-= ?==??+?=≈

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CBR简介

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2020年半导体行业深度研究报告

2020年半导体行业深度研究报告一、新科技起点，不可缺芯半导体位于电子行业中游。通过集成电路、分立器件、被动器件在PCB 上组合形成模组，构成了手机、电脑、工业、航空航天、军事装备等电子产品的核心。这些产品又直接影响到国家的发展、社会的进步以及个人的生活，完全改变了没有半导体时候的结构与数据流动形式。所以我们说半导体产业是支撑经济社会发展和保障国家安全的基础性和战略性产业。没有集成电路产业的支撑，信息社会就失去了根基，集成电路因此被喻为现代工业的“粮食”。再回顾过去的大科技趋势，我们已经经历了2000 年开始的数字时代以及从2010 年开始的互联时代，并开始逐步进入数据时代。对于数据，全球知名咨询公司麦肯锡表示：“数据，已经渗透到当今每一个行业和业务职能领域，成为重要的生产因素。人们对于海量数据的挖掘和运用，预示着新一波生产率增长和消费者盈余浪潮的到来。”大数据在物理学、生物学、环境生态学等领域以及军事、金融、通讯等行业存在已有时日，却因为近年来互联网和信息行业的发展而引起人们关注。在这个时代，科技的进步与发展潜移默化的改变了我们的生活习惯和思维方式。在这个时代，越来越多的科技从实验室走出来，走向大众。那科技的的基础是什么？科技的基础是硬件设备，而当代硬件设备的基础便是半导体。

近年在以物联网、可穿戴设备、云计算、大数据、新能源、医疗电子和安防电子等为主的新兴应用领域强劲需求的带动下，全球半导体产业恢复增长。半导体行业发展历程遵循一个螺旋式上升的过程，放缓或回落后又会重新经历一次更强劲的复苏。根据WSTS 统计，从2013 年到2018 年，全球半导体市场规模从3056 亿美元迅速提升至4688 亿美元，年均复合增长率达到8.93%。2019 年全球半导体市场规模受存储器价格滑坡同比下降12.8%到4089.88 亿美元。随着技术的进步，对硬件的要求也越来越高，对芯片的需求也越来越强烈，比如5G 基站建设、5G 周边应用落地、IoT、汽车电子、AI 等等。由于半导体的应用市场在各类终端智能化、互联化的过程中不断拓展，使得半导体产业与经济总量增速的相关度日益紧密，增长的稳健性加强、期性波动趋弱。知名半导体市调机构IC Insights 发布报告称，预计2018 年-2023 年全球的GDP 增长和半导体市场增长的相关性系数将从2010-2018 年的0.87 上升到0.88，而2000 年-2009 年该相关性系数仅为0.63。我们从几个细分领域来简述全球半导体市场未来将会保持繁荣。这都可说明未来科技需要更大程度上的硬件集成度、更高程度的半导体元器件电子化需求。（一）汽车日益电子化汽车是未来半导体行业最强劲的增长来源之一。传统汽车的芯片基本用于发动机控制、电池管理、娱乐控制、安全气囊控制、转向辅助等

被动元件电感LTCC射频元器件行业分析报告

被动元件电感LTCC射频元器件行业分析报告顺络电子

承载比(CBR)试验

承载比（CBR）试验及注意事项张克永安顺公路管理局一、目的和使用范围本试验只适用于在规定的试筒内制件后，对各种土和路面基层、底基层材料进行承载比试验。试件的最大颗粒控制在25mm以内，最大不得超过38mm。 CBR值是路基土或路面材料的强度指标，它是指试料贯入量达到2.5mm时的单位压力对标准碎石压入相同贯入量时标准荷载强度的比值，CBR值越大，土基强度越高。二、编写依据中华人民共和国行业标准JTJ051-93《公路土工试验规程》。三、技术要求及技术条件 ②表列强度按《公路土工试验规程》，对式样浸水96h的CBR试验方法测定； ③黄土、膨胀土及盐渍土的填料强度，分别按各章的规定办理。四、使用的仪器设备 1、圆孔筛，孔径38mm、25mm及5mm各一个； 2、试筒，内径152mm，高170mm的金属圆筒、环高50mm、内垫块直径151mm，高50mm，夯击底板； 3、路面材料强度仪，能量不小于50KN，能调节贯入速度至每分钟贯入1mm； 4、百分表； 5、试件顶面的多孔板； 6、多孔底板； 7、测膨胀量时支承百分表的架子； 8、荷载板，直径150mm，中心孔眼直径52mm； 9、水槽； 10、台秤（感量为试件用量的0.1%）、直尺、修土刀、方盘、滤纸、脱模器等与击实试验供用。五、试样制备试样在规定试筒内制件后对各种土和路面基层、底基层材料进行承载比试验，试样的最大粒径宜控制在25mm以内，最大不得超过38mm。采取有代表性试料50Kg，

用四分法将试样分成9份，按击实求出的最佳含水量进行加水焖样一昼夜。六、试验步骤 1、将焖好的试样制9个试件，每层击实次数分别为30次、50次和98次，按3层法击实，每层需土1700g左右，击实后的试样高出筒高1—2mm，卸下套环，用修土刀削平击实后的试件，并称重。试筒放在多孔板上拧紧，在多孔板上加4块荷载板将试筒与多孔板一起放入水槽内安装百分表并读初读数，向水槽注水，到试件顶部大约25mm，试件浸泡4昼夜后读取百分表终读数，从水槽中取出试件静置15min后，卸荷载板和多孔板底板和滤纸称重。 2、将泡水终了的试件放到路面材料强度仪的升降台上，调整偏球座，使贯入杆与试件顶面全面接触，并放置好荷载板。先在贯入杆上加45N荷载，然后将百分表指针调整至零点，加荷载使贯入杆以1~1.25mm/min的速度压入试件,并开始记录。 3、试验完毕后将试件脱摸，清洗试筒、涂油。检查设备完好情况，并注油。七、计算 CBR值按下式计算： CBR=P/7000×100 式中 CBR—承载比，（%）； P —单位压力，（Kpa）；同时计算贯入量为5mm时的承载比： CBR=P/10500×100 如贯入量为5mm时的承载比大于2.5mm时的承载比，则试验要重作，如果结果仍然如此，则采用5mm时的承载比。泡水后的吸水量按下式计算： W0=m3-m2 式中W0—泡水后试件的吸水量，（g）； m3—泡水后试筒和试件的合量，（g）; m2—试筒试件的合质量，（g）; 八、报告 1、材料颗粒组成，最佳含水量（%），最大干密度（g/cm3）； 2、材料的承载比（%）承载比小于100，准确到5%。承载比大于100，准确到10%； 3、材料的膨胀量（%）。九、注意事项 1、击实，求最大干密度：最好选择大击实筒，它与CBR试模一致，可以减小仪器间的误差，击实筒的体积一定要准确，可用灌水法求其体积。在击实过程中应随时观察锤头是否粘土，若有应及时清除，以免击实功受到影响，尽量使用同一击实筒、底板、垫块完成同一土样的击实。 2、制件：CBR制件是整个试验的关键，先应标定每个试件的体积，使试验保持干燥、洁净，制件前用拧干的湿毛巾润湿内壁。在最佳含水量的基础上增加0.5%的含水量来加水焖料,弥补在拌制过程中的水份损失,按十一个试件的质量备料,一个用来复核击实的最大干度,其余料全部用来制成十个试件。试件成型，根据不同密实度（98 次按100%最大干密度、50次按94.5~95.5%最大干密度、30次按91.5~92%最大干密度，高度按12.5cm）来计算每个试件每层的所需的土样质量，并按计算质量准确加料。 3、贯入：本环节最重要的就是测力环的选择，在“制件”中提到要制10个件，多出

2018年MLCC行业分析报告

2018年MLCC行业分析报告 2018年7月

目录一、便携式应用推动MLCC持续小型化 (4) 1、MLCC：广泛应用于便携式电子产品 (4) 2、百亿美金市场，国内是最大出海口 (5) 3、小型化持续推进 (5) 二、需求端：多个下游领域支撑MLCC需求增长 (6) 1、通信升级带动MLCC用量提升 (6) 2、汽车电动化为MLCC带来新的增长点 (8) 3、物联网领域的增长有望成为MLCC下一个爆发点 (9) 三、供给端：日系厂商退出带来缺口，涨价不断 (10) 1、MLCC市场集中度高，日韩厂商为主 (10) 2、日系厂商退出中低端市场，供需缺口出现 (12) 3、扩产聚集在车载市场，目前缺口难以填补，涨价不断 (13)

便携式应用推动MLCC持续小型化。MLCC具备体积小、稳定性高、耐压高等优点被广泛应用于消费电子、通信、汽车、工业等领域。根据博思数据2017 年MLCC全球市场规模约为100亿美元左右，中国市场规模约为490亿元人民币，占全球的70%以上。高容值、高可靠度和小尺寸是MLCC技术发展的两大趋势。需求端：多个下游领域支撑MLCC需求增长。一方面手机单机用MLCC不断提升，以iPhone 系列为例，iphone4S的MLCC用量约为500颗，而iPhoneX 的MLCC用量达到了1100颗左右，平均每一代iPhone 的MLCC用量都会提高20%左右。另一方面随着汽车新能源化，MLCC 在汽车中的用量也有望成倍增长。根据太阳诱电统计，传统燃油动力车被动元件需求量为6000~8000颗，混动汽车增长至10000颗，纯电动车为14000颗，其中MLCC占将近一半。供给端：日系厂商退出带来缺口，涨价不断。供给端日系厂商退出中低端领域，带来缺口约500亿只/月。日系厂商扩产集中在车载产品，反观0201-0805 的尺寸段，主流厂商仅国巨、华新科等大中华地区厂商有扩产计划，扩充产能约为150亿只/月，产能全部释放缺口依然存在。考虑到需求稳定增长，日本厂商继续退出一般类型产品，以及国际厂商扩产进度普遍较慢，考虑到这些原因，预计MLCC缺货行情短期难以缓解。建议关注国内MLCC领域三环集团、火炬电子等。

电子元器件行业分析总结

2010年我们更关注元器件上市公司在业绩恢复方面出现的分化. 第一个投资逻辑是寻找在2010年业绩仍能出现快速恢复的公司。在经济持续向好的预期下，新投资项目将是决定元器件公司业绩增长的主要因素。我们的第二个投资逻辑是结合上市公司的投资项目情况以及潜在投资能力来寻找业绩可能出现快速增长的公司。我们看到，产业的技术创新依旧活跃，产品升级是产业增长的主要动力，新的细分市场伴随着新产品出现，相关的元器件公司将受益于这些细分市场的高成长。我们的第三个投资逻辑是结合终端应用的发展趋势寻找能够分享细分市场高增长的公司。

将电子元器件行业重点公司按产品分类如下（重点关注的公司用粗体字标电子类上市公司都是小市值公司，由于产品庞杂，重复产品的公司不多，细分市场特别多。从以上分类方式来探讨电子元器件行业的2009 年投资机会： 1）对周期型公司，我们观察和等待行业反转；

2）对技术进步型公司，我们首先观察企业能不能抗得过寒冬，其次观察是否有资金在持续投入和研发； 3）对客户决定型公司，首先观察客户的状况，客户状况与公司状况是荣损相连，不可能存在例外； 4）对服务型的公司，情况可能稍好一些，但是仍然观察下游需求状况。行业特点 1行业增速趋缓，结构升级明显，产量增速放缓但收入增速加快，这主要是显示器产品结构升级（液晶） 08年1-10 月我国片式元件产量31.7%的增速远超07年同期；尽管电子元件制造业主营业务收入增速不如07年同期，但22.3%的工业增加值增幅远高于07年同期（8.7%） 2 大进大出，而且进口大于出口，两头受压，定价能力弱处于中间配套零件地位的电子产品，一方面不能控制上游大宗原料价格波动，一方面自身产品价格往往被下游整机企业控制，所以大部分电子企业实际上缺乏自主定价能力。大量进口高端产品、大量出口低端产品，是很长时间以来中国电子元件市场的最大特征 3 外资占主导地位资企业的出口比重很高 2008 年前三季度，中国大陆电子信息制造业出口总额为3751 亿美元，其中外资占据86%的份额。在第一阶段低端产品向中国企业转移之后，新的面向中国企业产业转移阶段还未到来。行业面临发展瓶颈：低端产能过剩，价格竞争严重，盈利水平越来越低，高端领域受技术瓶颈限制，难以进入近几年，国电子产业依靠承接国际产能转移，取得了快速发展。2003-2007年半导体分立器件、集成电路、电子元件的年平均复合增长率分别为：33.5%、28.1%、19%，都远高于同期全球增速。然而，我们所承接的主要是底端产能。虽然电子类公司都有一定科技含量，但总体落后于国际，而且真正具备自主核心技术和持续研发的公司极少，相关企业大多实际上加工制造业（工厂），基本不涉及品牌、渠道、服务和服务，属于是制造产业的一环，加工性质就尤为突出，企业的持续盈利能力弱。2007年国主要电子元器件子行业的人均销售收入大都只有20-30万元/人的水平，与国外同类企业差距在十倍到几十倍之间。所以说，过去几年，我国电子产业的发展主要依赖低要素成本，竞争发生主要是价格战。这种低成本驱动的发展模式带来了一个严重后果，即对技术创新能力的忽视，而技术创新能力对电子企业来说是最为重要的。目前，行业整体面临技术创新瓶颈。行业面临很多问题：产业链不完整、核心技术缺乏和行业标准制定权缺失。首先，产业链不完整主要在于上游的装备制造设备、材料类的缺乏和下游品牌企业和产品的缺乏。第二，就是核心技术的缺乏。第三，行业标准制定权的缺失，导致公司在发展过程中受国际其他企业的排挤需求因素需求成为影响行业发展的最核心要素从本轮景气调整的深层背景上看，行业周期与全球经济波动的叠加使得需求在判断行业景气变动中的重要性空前上升，产业难以像以往那样仅通过供给的自我调节实现产业供需的平衡，需求的恢复成为景气恢复的先决条件。经济衰退致使需求的三驾马车同时减速

CBR值与压实度

CBR值与压实度土体作为材料，其应力应变关系很难按照“理想线弹-塑性模型”明确界定为弹性（弹性模量）或塑性（c、φ）。 CBR值是指试料贯入量达2.5mm或5mm时，单位压力对标准碎石压入相同贯入量时标准荷载强度(7MPa或10.5MPa)的比值。 CBR击实试件预先浸水饱和，以模拟材料在使用过程中的最不利状态；贯入过程中在试件上面放置荷载板，以模拟路面结构对路基的附加应力。即使按照“理想线弹-塑性模型”简化分析，对于绝大多数土样，2.5或5mm 的贯入量，应该说试样局部已经达到剪切破坏（破坏前和未破坏部分变形与E 相关，破坏部分变形与c、φ相关）。作为加载过程，CBR试验和现场荷载试验等有类似之处。贯入过程的力-位移曲线与荷载试验s-p加载曲线也类似，线型呈上凸状：起始段平缓，末尾段陡峭。可以借鉴s-p曲线大致来界定试样的“弹性变形阶段-->局部破坏开始的弹塑混合阶段-->整体破坏阶段”。抗剪强度C、内摩擦角和CBR的关系，我想用CBR的值确定抗剪强度C、内摩擦角然后用FLAC进行建模，你提醒了我一点，“可以借鉴s-p曲线大致来界定试样的“弹性变形阶段-->局部破坏开始的弹塑混合阶段-->整体破坏阶段””谢谢，希望大家再给点建议呀给一个CBR（%）与DCP动探[击数/50mm]的关系。 CBR(%)= 5.0328x^1.1154 x = 击数/50mm 测新技术

CBR又称加州承载比，是California Bearing Ration的缩写，由美国加利福尼亚州公路局首先提出来，用于评定路基土和路面材料的强度指标。在国外多采用CBR作为路面材料和路基土的设计参数。我国现行沥青和水泥混凝土路面设计规范，对路面、路基的设计参数系采用回弹模量指标，而在境外修建的公路工程多采用CBR指标。为了进一步积累经验用于实际，以促进国际学术交流，参考了国内外的情况，将CBR指标列入《公路路基设计规范》（JTJ 013-95）和《公路路基施工技术规范》（JTJ 033-95），作为路基填料选择的依据。一、 CBR值室内试验技术 1．主要仪器设备（1）圆孔筛：孔径38mm、25mm、20mm、及5mm筛各1个。（2）重型标准击实仪器设备：试筒、夯锤等。（3）贯人杆：端面直径50mm、长l00mm的金属柱。（4）路面材料强度或其它载荷装置：能量不小于：50kN。（5）百分表、测力环、荷载板等。 2．试验原理试验时，按路基施工时的最佳含水量及压实度要求在试筒内制备试件；为了模拟材料在使用过程中的最不利状态，加载前饱水4昼夜；在浸水过程中及贯人试验时，在试件顶面施加荷载板以模拟路面结构对土基的附加应力；贯人试验中，材料的承载能力越高，对其压人一定贯人深度所需施加的荷载越大。所谓CBR值，就是试料贯人量达到2.5mm或5mm时的单位压力与标准碎石压人相同贯人量时标准荷载强度（7MPa或10.5MPa）的比值，用百分数表示。 3．试验技术要求（1）试验采用风干试料，按四分法备料。（2）做击实试验，求试料的最大干密度和最佳含水量。

行业分析报告及研究思路

行业分析报告：需求分析：人口基数、人口构成、消费意识、支付能力以及发病趋势。两个失衡点： 1、政府支出占医疗比例偏小 2、由于庞大的人口基数，人均医疗费用偏少需求分析--海外需求：研究外包、制造外包、临床外包、原料药采购、制剂采购存在问题： ①缺乏创新，（生产许可审批过于宽松造成低水平重复性建设严重，供给出现结构性过剩，GMP认证加剧了过剩）； ②医改政策对医药流通和用药环节产生重大影响，使部分产品技术含量低，研发实力弱的企业产能过剩问题更加突出； ③医药商业结构性过剩表现为企业多小散乱，区域分割严重，照成市场集中度低，缺乏规模效应，物流配送效率低。 3、行业并购整合将加速 1995-2000：水平整合； 2000-2005：垂直整合； 2005年后：国际化，专业化，企业做大做强（政府为主导的并购整合将主要出现在大型国有医药集团，偏重于资源整合）（民营企业和新介入医药领域的公司则主要采取市场化的模式，主要偏重于项目产品选择和作为财务投资人） 4、药品价值链 ①创新，意味着定价权和市场垄断，为企业赢得更多利润空间； ②中国市场存在失衡现象，创新缺失，不规范的竞争造成医药企业表面的高盈利。

5、药品分类管理 ①医保目录药品：甲类目录药品+乙类目录药品（医保目录定制；国家制定最高零售价；招标采购；国产药物为主） ②非目录药品：非医保报销范围 ③处方药：持医生处方购买；不能在大众广告宣传；在医药商业系统销售 ④非处方药：甲类、乙类无需处方购买 6、药品价格管制政府定价药品，医保目录药品、管制生产垄断经营药品，民族药、部分中药饮片和亿元制剂市场定价药品：非政府定价范围内药品，需进行价格备案 7、药品专利申请随着国内医药行业的发展，如何防范专利纠纷和利用专利支持自身发展将会越来越重要，由于缺乏创新，前期95%以上的新药都是仿制，在全球化的浪潮中，医药企业也将勉励更多的专利困扰。学习、进步、挑战、创新是医药行业发展的必经之路。 8、细分行业基础分析：产业特征多元化