• Journal of Microbiology and Biotechnology
• /
• 제27권2호
• /
• pp.306-315
• /
• 2017

Metabolic engineering with a high-yielding mutant, A. terreus AN37, was performed to enhance the production of itaconic acid (IA). Reportedly, the gene cluster for IA biosynthesis is composed of four genes: reg (regulator), mtt (mitochondrial transporter), cad (cis-aconitate decarboxylase), and mfs (membrane transporter). By overexpressing each gene of the IA gene cluster in A. terreus AN37 transformed by the restriction enzyme-mediated integration method, several transformants showing high productivity of IA were successfully obtained. One of the AN37/cad transformants could produce a very high amount of IA (75 g/l) in shake-flask cultivations, showing an average of 5% higher IA titer compared with the high-yielding control strain. Notably, in the case of the mfs transformants, a maximal increase of 18.3% in IA production was observed relative to the control strain under the identical fermentation conditions. Meanwhile, the overexpression of reg and mtt genes showed no significant improvements in IA production. In summary, the overexpressed cis-aconitate decarboxylase (CAD) and putative membrane transporter (MFS) appeared to have positive influences on the enhanced IA productivity of the respective transformant. The maximal increases of 13.6~18.3% in IA productivity of the transformed strains should be noted, since the parallel mother strain used in this study is indeed a very high-performance mutant that has been obtained through intensive rational screening programs in our laboratory.

• 한국CDE학회논문집
• /
• 제9권4호
• /
• pp.373-381
• /
• 2004

Using standard components of a press die is recognized as a way for a cost reduction and a short lead time. It also provides a way for a quick maintenance of a die under repair. It is expected to contribute to integration of CAD/CAM system for manufacturing dies in the future. This paper presents a 3D CAD library which is constructed using the standard components and is used for designing a press die. This 3D CAD library is generated by a database system made of Microsoft Access for standard components and by CATIA V5 R10 API for geometric features. The library is implemented using Visual Basic 6.0 utility of CATIA API function in the Windows NT environment. It creates a 3D model of the standard components of press die easily when a die designer inputs numerical values of geometric features and the BOM of the completely assembled parts. It also generates automatically the assembly drawing of die set by using variables for standard values of die parts. Therefore users can save the cost of time to design the press die components, and even a beginner can use this program with ease. The test results of the 3D CAD library for designing shearing and bending dies verify its usefulness and feasibility.

• 한국CDE학회논문집
• /
• 제7권3호
• /
• pp.157-169
• /
• 2002

In the initial stages of ship design, designers represent geometry, arrangement, and dimension of hull structures with 2D geometric primitives such as points, lines, arcs, and drawing symbols. However, these design information(‘2D geometric primitives’) defined in the drawing sheet require more intelligent translation processes by the designers in the next design stages. Thus, the loss of design semantics could be occurred and following design processes could be delayed. In the initial design stages, it is not easy to adopt commercial 3D CAD systems, which have been developed f3r being used in detail and production design stages, because the 3D CAD systems require detailed input for geometry definition. In this study, a semantic product model data structure was proposed, and an initial structural CAD system was developed based on the proposed data structure. Contents(‘product model data and design knowledges’) of the proposed data structure are filled with minimal input of the designers, and then 3D solid model and production material information can be automatically generated as occasion demands. Finally, the applicability of the proposed semantic product model data structure and the developed initial structural CAD system was verified through application to deadweight 300,000ton VLCC(Very Large Crude oil Carrier) product modeling procedure.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 하계학술대회 논문집 B
• /
• pp.808-810
• /
• 2002

Higher current-rating and improved thermal performance are being sought for existing medium-voltage vacuum circuit breakers(VCB) in order to meet market needs which require to be compact and downsized. In this paper, thermal performance of medium voltage vacuum circuit breaker was investigated through experiments and numerical analysis. We changed several major parameters of current-rating and heat sink affecting on thermal behaviors in the breaker and observed the results. To predict the temperature distribution in complex three-dimensional (3-D) VCB components and gas, the commercial package was used to simulate conjugate heat transfer. Although some assumptions and simplifications were introduced to simulate the model, results from the computational model were in good agreement with actual temperature rise measurements obtained from experiments.

• 대한치과보철학회지
• /
• 제48권1호
• /
• pp.1-7
• /
• 2010

연구 목적: 본 연구에서는MAD/MAM 시스템으로 제작된 지르코니아 코어를 통상적인 방법으로 제작된 금속-도재관 코어와 CAD/CAM 시스템으로 제작된 코어와의 변연부 적합도를 비교 분석해 보고자 한다. 연구 재료 및 방법: 레진치를 전부 도재관 제작을 위한 형태로 삭제하고, 이를 복제하여 석고 모형을 제작하였다. 석고 모형에 대해 금속-도재관, CAD/CAM ($Cercon^{(R)}$), 3종의 MAD/MAM 시스템 ($Ceramill^{(R)}$, $Rainbow^{(TM)}$, $Zirkonzhan^{(R)}$)으로 각각 10개의 코어를 제작하였다. 제작된 코어를 다이에 합착하여 광학 현미경 상에서 50배율로 변연 간격을 관찰, 계측하였다. 측정된 결과는 one-way ANOVA test로 분석하고, Tukey's HSD test로 사후검정 하였다. 결과: 각 시스템에서 변연 간격의 평균과 표준 편차는 금속-도재관 코어 $51.97{\pm}23.38{\mu}m$, $Cercon^{(R)}$ $62.16{\pm}25.88{\mu}m$, $Ceramill^{(R)}$ $67.64{\pm}40.38{\mu}m$, $Rainbow^{TM}$ $125.07{\pm}42.19{\mu}m$, $Zirkonzhan^{(R)}$ $105.02{\pm}44.61{\mu}m$로 측정되었다. 결론: 금속-도재관 코어나 CAD/CAM에 비해 MAD/MAM 방식으로 제작된 코어의 변연 간격이 큰 것으로 나타났다 (P < .05). MAD/MAM 시스템 내에서도 $Ceramill^{(R)}$, $Zirkonzhan^{(R)}$, $Rainbow^{TM}$ 순으로 변연 간격이 작은 것으로 측정되었으며, 이중 $Ceramill^{(R)}$은 CAD/CAM 시스템인 $Cercon^{(R)}$과 변연 간격에 유의차가 없었다.

• 한국기계연구소 소보
• /
• 통권17호
• /
• pp.93-97
• /
• 1987

This paper is concerned on kinematic analysis and simulation of an automatic feeding mechanism and a curved inverse earn. The main objective is the development 0 fan algorithm of the earn-feeding mechanism and a CAD program. The computer program CACAFS (Computer-Aided Cam and Automatic Feeding System) is developed by using the state-of-the-art for CAD. Thus, the program CACAFS is independent of computer hardwares and also interactive. As the second part of paper, this paper introduces the technique for the mechanism simulation and graphics-oriented CAD programming. The first part of r paper presents the algorithm to analyze the motion of the inverse earn and the automatic feeding mechanism.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 1994년도 춘계공동학술대회논문집; 창원대학교; 08월 09일 Apr. 1994
• /
• pp.703-712
• /
• 1994

This paper presents an automatic conversion of machining data from the orthographic views of press mold by feature recognition rule. The system includes following 6 modules : separation of views, function support, dimension text recognition, feature recognition, dimension text check and feature processing modules. The characteristic of this system is that with minimum user intervention, it recognizes basic features such as holes, slots, pockets and clamping parts and thus automatically converts CAD drawing details of press mold into machining data using 2D CAD system instead of using an expensive 3D Modeler. The system is developed by using IBM-PC in the environment of AutoCAD R12, AutoLISP and MetaWare High C. Performance of the system is verified as a good interfacing of CAD and CAM when applied to a lot of sample drawings.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2001년도 춘계학술대회 논문집
• /
• pp.3-6
• /
• 2001

The present work concerns rapid tooling technology based on three-dimensional CAD/CAM. Two types of tooling processes have been introduced : the quick delivery molding(QDM) process and the rapid tooling(RT) process using a rapid prototyping system. Both processes are based on three-dimensional CAD/CAM technology and realize a paperless manufacturing system with a high efficiency. The proposed approach has been applied to the product development for various electrical parts, and the final delivery has been reduced as compared with the traditional approach.

• Structural Engineering and Mechanics
• /
• 제30권2호
• /
• pp.225-245
• /
• 2008

T-splines are recently proposed mathematical tools for geometric modeling, which are generalizations of B-splines. Local refinement can be performed effectively using T-splines while it is not the case when B-splines or NURBS are used. Using T-splines, patches with unmatched boundaries can be combined easily without special techniques. In the present study, an analysis framework using T-splines is proposed. In this framework, T-splines are used both for description of geometries and for approximation of solution spaces. This analysis framework can be a basis of a CAD/CAE integrated approach. In this approach, CAD models are directly imported as the analysis models without additional finite element modeling. Some numerical examples are presented to illustrate the effectiveness of the current analysis framework.

• International Journal of CAD/CAM
• /
• 제11권1호
• /
• pp.1-10
• /
• 2011

Product lifecycle management (PLM) is a new business strategy for enterprise's product R&D. A PLM system holds and maintaining the integrity of the product data produced throughout its entire lifecycle. There is, therefore, a need to build a safe and effective product data model to support PLM system. The paper proposes a domain-based product data model for PLM. The domain modeling method is introduced, including the domain concept and its defining standard along the product evolution process. The product data model in every domain is explained, and the mapping rules among these models are discussed. Mapped successively among these models, product data can be successfully realized the dynamic evolution and the historical traceability in PLM system.