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Lightweight design of 45000r/min spindle using full factorial design and extreme vertices design methods

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Journal of Central South University 2011年第1期18卷 153-158页

作者： PARK Seong-jin lee choon-man HWANG Young-kug Department of Mechanical Design and Manufacturing Engineering Changwon National University

Factors for determining the spindle size are the shaft diameter, positions of bearing and motor, and entire length of the spindle. Then, it is important to find the assembling of the optimal design variables, which satisfy the stiffimss and rotational speed required to the spindle. A general full factorial design method was used to verify some factors that affect the natural frequency of a spindle. It is verified that the shorter shaft length and bearing span length represent the higher natural frequency, and there are some effects according to the change in the levels of factors. The detailed spindle dimension is determined by applying an EVD method, which can define the optimal bearing position through considering the limiting condition. Based on the estimated regression model, the optimal spindle size and bearing distance that can improve the primary natural frequency are obtained, and the influence of design factors on the natural frequency is also analyzed.

关键词： high-speed spindle extreme vertices design natural frequency lightweight design full factorial design

Development of CAD/CAM system and profile measuring device for CNC grinding machine to obtain an optimal grinding speed

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Journal of Central South University 2011年第1期18卷 146-152页

作者： LIM Sang-Heon KIM Jae-Hyun lee choon-Man Agency of Promoting Technology Innovation Gyeongnam TechnoparkChangwon 641-465Korea School of Mechatronics Changwon National University

Cam mechanics is one of the most popular devices for generating irregular motions and is widely used in automatic equipment,such as textile machines,internal combustion engines,and other automatic *** order to obtain a positive motion from the follower using a rotating cam,its shape should be correctly designed and *** development of an adequate CAD/CAM system for a cam profile CNC grinding machine is necessary to manufacture high-precision *** purpose of this study is the development of a CAD/CAM system and profile measuring device for a CNC grinding machine to obtain an optimal grinding speed with a constant surface *** types of disk cams were manufactured using the proposed algorithm and procedures to verify effectiveness of the developed CAD/CAM system.

关键词： cam CAD/CAM system CNC grinding machine optimal grinding speed

Generation of polarized electron beams through self-injection in the interaction of a laser with a pre-polarized plasma

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High Power Laser Science and Engineering 2024年第3期 67-73页

作者： L.R.Yin X.F.Li Y.J.Gu N.Cao Q.Kong M.Büscher S.M.weng M.Chen Z.M.Sheng Key Laboratory of Nuclear Physics and Ion-beam Application (Mo E) Institute of Modern Physics Department of Nuclear Science and Technology Fudan University State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences SANKEN (Institute of Scienti?c and Industrial Research) Osaka University Sichuan Research Institute Shanghai Jiao Tong University Peter Grünberg Institut (PGI-6) Forschungszentrum Jülich Institut für Laser- und Plasmaphysik Heinrich-Heine-Universit?t Düsseldorf Key Laboratory for Laser Plasmas (Mo E) School of Physics and Astronomy Shanghai Jiao Tong University Collaborative Innovation Center of IFSA Shanghai Jiao Tong University Tsung-Dao lee Institute Shanghai Jiao Tong University

Polarized electron beam production via laser wakefield acceleration in pre-polarized plasma is investigated by particlein-cell simulations. The evolution of the electron beam polarization is studied based on the Thomas±Bargmann±Michel±Telegdi equation for the transverse and longitudinal self-injection, and the depolarization process is found to be influenced by the injection schemes. In the case of transverse self-injection, as found typically in the bubble regime, the spin precession of the accelerated electrons is mainly influenced by the wakefield. However, in the case of longitudinal injection in the quasi-1D regime (for example, F. Y. Li et al., Phys. Rev. Lett. 110, 135002 (2013)), the direction of electron spin oscillates in the laser field. Since the electrons move around the laser axis, the net influence of the laser field is nearly zero and the contribution of the wakefield can be ignored. Finally, an ultra-short electron beam with polarization of 99%can be obtained using longitudinal self-injection.

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Prediction of preheating conditions for inclined laser assisted machining

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Journal of Central South University 2012年第11期19卷 3079-3083页

作者： KIM Kwang-sun lee choon-man School of Mechatronics Changwon National UniversityChangwon 641-773Korea

For laser assisted machining,shape of preheating laser heat source is changed irregularly because of complexity of material ***,the preheating temperature should be controlled by adjusting the feed rate or the laser *** analyses of the laser assisted machining process for inclination planes were *** analyzing the obtained temperature profile,a proper feed rate control method was proposed according to the inclination *** addition,the temperature distribution of the cross section after feed rate control was *** correlation equation between inclination angles and adjusted proper feed rate was *** results of this analysis can be used to predict the preheating effect on workpiece and can be applied as a preheating temperature control method in laser assisted machining processes.

关键词： laser assisted machining inclination angle feed rate control cross section

Semantics-oriented approach for information interoperability and governance:towards user-centric enterprise architecture management

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Journal of Zhejiang University-Science C(Computers and Electronics) 2010年第4期11卷 227-240页

作者： Imran GHANI choon Yeul lee Sung Hyun JUHN Seung Ryul JEONG School of Business IT Kookmin University

Enterprise architecture (EA) efforts focus on business, technology, data, and application architecture, and their integration. However, less attention has been given to one of the most critical EA elements, i.e., users (EA audiences). As a result, existing EA management systems (EAMS) have become old, large, content-centric document-repositories that are unable to provide meaningful information of use to the enterprise users and aligned with their needs and functional scope. We argue that a semantic technology based mechanism focusing on enterprise information and user-centricity has the potential to solve this problem. In this context, we present a novel ontology-based strategy named the user-centric semantics-oriented EA (U-SEA) model. Based on this model, we have developed a user-centric semantics-oriented enterprise architecture management (U-SEAM) system. Our approach is generic enough to be used in a wide variety of user-centric EAM applications. The results obtained show computational feasibility to integrate and govern enterprise information and to reduce complexity with respect to interoperability between enterprise information and users.

关键词： Enterprise architecture management system (EAMS) Ontology Recommender system User-centric Semantic Web Framework

NC code generation for laser assisted turn-mill of various type of clovers and square section members

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Journal of Central South University 2012年第11期19卷 3064-3068页

作者： CHOI Jun-young lee choon-man Department of Mechanical Design & Manufacturing Engineering Changwon National UniversityChangwon 641-773Korea

Laser assisted turning （LAT） is one of the advanced machining technologies, which uses laser power to heat the surface of a workpiece before the material is removed. It has several advantages of low manufacturing costs, high productivity and high qualities to machine difficult-to-cut materials such as silicon nitride, muUite, zirconia and Ni. A large part of studies on LAT have been focused on a round bar. With increasing demands for high quality products and high performance engineering system, the researches on LAT for clover and square section members are necessary. But, these workpieces are impossible to be machined on conventional CNC lathe and to generate NC code with current CAM softwares. As a basic research for combining LAT with a tilting index table type 5-axis machining center, i.e. laser assisted turn-mill, a new method is suggested to generate NC code that can process various types of clover and square section members through development of C＋＋ program.

关键词： laser assisted turning (LAT) NC code clover section turn-mill square section turn-mill

Characterization of La-promoted Ni/Al_2O_3 catalysts for hydrogen production from glycerol dry reforming

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Journal of Energy Chemistry 2014年第1期23卷 15-21页

作者： Kah weng Siew Hua Chyn lee Jolius Gimbun Chin Kui Cheng Centre of Excellence for Advanced Research in Fluid Flow Universiti Malaysia PahangLebuhraya Tun Razak26300 GambangKuantan PahangMalaysia Faculty of Chemical & Natural Resources Engineering Universiti Malaysia PahangLebuhraya Tun Razak26300 GambangKuantan PahangMalaysia

In the current paper, dry(CO2)-reforming of glycerol, a new reforming route, was carried out over alumina(Al2O3)-supported, non-promoted and lanthanum-promoted nickel(Ni) catalysts. Both sets of catalysts were synthesized via a wet co-impregnation procedure. Physicochemical characterization of the catalysts showed that the promoted catalyst possessed smaller metal crystallite size, hence higher metal dispersion compared to the virgin Ni/Al2O3catalyst. This was also corroborated by the surface images captured by the FESEM analysis. From temperature-programmed calcination analysis, the derivative weight profiles revealed two peaks, which represent a water elimination peak at a temperature range of 373 to 473 K followed by nickel nitrate decomposition from 473 to 573 K. In addition, BET surface area measurements gave 85.0 m2 g-1for the non-promoted Ni catalyst, whilst the promoted catalysts showed an average of 1% to 6% improvement depending on the La loadings. Significantly, reaction studies at 873 K showed that glycerol dry reforming successfully produced H2. The 2%La-Ni/Al2O3catalyst, which possessed the largest BET surface area, gave an optimum H2generation(9.70%) at a glycerol conversion of 24.5%.

关键词： Ni catalysts dry reforming lanthanide promotion reaction kinetics

Estimation of deformed laser heat sources and thermal analysis on laser assisted turning of square member

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Journal of Central South University 2012年第2期19卷 402-407页

作者： KIM Jae-hyun KIM Kwang-sun CHOI Jun-young lee choon-man Department of Mechanical Design and Manufacturing Engineering Changwon National University

Laser assisted machining （LAM） has difficulties in estimating temperature after applying a LAM process due to its very small heat input area, large energy and movement. In particular, in the case of laser assisted turning （LAT） process, it is more difficult to estimate the temperature after preheating because it has a shape of ellipse when a laser heat source is rotated. A prediction method and thermal analysis method for heat source shapes were proposed as a square shaped member was preheated. The temperature distribution was calculated according to the rotation of the member. Compared with the results of the former study, the maximum temperature of the calculation results, 1 407.1 ℃, is 8.5 ℃ higher than that of the square member, which is 1 398.6 ℃. In a LAT process for a square member, the maximum temperature is 1 850.8 ℃. It is recognized that a laser power control process is required because square members show a maximum temperature that exceeds a melting temperature at around a vertex of the member according to the rotation.

关键词： laser assisted machining laser assisted turning laser preheating laser power control

Hepatocellular carcinoma masquerading as a bleeding gastric ulcer: A case report and a review of the surgical management

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World Journal of Gastroenterology 2007年第33期13卷 4523-4525页

作者： Johnny CA Ong Pierce KH Chow weng-Hoong Chan Alex YF Chung choon Hua Thng Wai-Keong Wong Department of General Surgery Singapore General Hospital Singapore 169608 Singapore Department of Oncologic Radiology National Cancer Centre Singapore Singapore

Hepatocellular Carcinoma (HCC) is a common malignancyworldwide. While bleeding from the gastrointestinal tract(BGIT) has a well known association with HCC, suchcases are mainly due to gastric and esophageal *** as a result of invasion of the gastrointestinal tractby HCC is extremely rare and is reportedly associatedwith very poor prognosis. We describe a 67-year-oldmale who presented with BGIT. Endoscopy showed thesite of bleeding to be from a gastric ulcer, but endoscopictherapy failed to control the bleeding and emergencysurgery was required. At surgery, the ulcer was found tohave arisen from direct invasion of the gastrointestinaltract by HCC of the left lobe. Control of the bleedingwas achieved by surgical resection of the HCC en-bloc with the lesser curve of the stomach. The patientremains alive 33 mo after surgery. Direct invasion of thegastrointestinal tract by HCC giving rise to BGIT is veryuncommon. Surgical resection may offer significantlybetter survival over non-surgical therapy, especially if thepatient is a good surgical candidate and has adequatefunctional liver reserves. Prognosis is not uniformly grave.

关键词： Hepatocellular carcinoma Gastrointestinal bleeding Stomach invasion Hepatectomy