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NUMERICAL IMPLEMENTATION FOR A 2-D THERMAL INHOMOGENEITY THROUGH THE DYNAMICAL PROBE METHOD

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Journal of Computational Mathematics 2010年第1期28卷 87-104页

作者： lei yi Kyoungsun Kim Gen Nakamura Institute of mathematics Fudan University Shanghai 200433 China Department of Mathematics Hokkaido University Sapporo Japan

In this paper, we present the theory and numerical implementation for a 2-D thermal inhomogeneity through the dynamical probe method. The main idea of the dynamical probe method is to construct an indicator function associated with some probe such that when the probe touch the boundary of the inclusion the indicator function will blow up. From this property, we can get the shape of the inclusion. We will give the numerical reconstruction algorithm to identify the inclusion from the simulated Neumann-to-Dirichlet map.

关键词： Heat equation Dynamical probe method Neumann-to-Dirichlet map.

Construction of Paired States in Axially Symmetric Nuclei and Diabolic Pair Transfer

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Chinese Physics Letters 1998年第5期15卷 323-325页

作者： lei yi-an ZENG Jin-yan Department of Physics Peking UniversityBeijing 100871

In axially symmetric nuclei,three forms of paired states can be constructed,i.e.,monopole pair,signature pair and±Ωpair,which are the eigenstates of(J^(2),Jz),(J^(2)_(z),R_(x)(π)),and Jz,*** the cranked shell model,though the energy spectra atω=0 are the same for three types of pair interactions,the spectra and spin alignments forω≠0 are different to a certain *** is found that theωvariation of the pair transfer amplitude,particularly the diabolic pair transfer,is quite different for different pair interactions.

关键词： spectra signature states

A Retrieval Algorithm of Sheet Metal Parts Based on Relationships of Features

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Chinese Journal of Aeronautics 2012年第3期25卷 453-472页

作者： WANG Dawei YAN Guangrong lei yi ZHANG Jiaying School of Mechanical Engineering and Automation Beihang University Beijing 100191. China Modern Education Center. Shandong University of Science and Technology. Ta ian 271019. China

With the rapid increase in the number of three-dimensional （3D） models each year, to quickly and easily find the part desired has become a big challenge of enterprises. Meanwhile, many methods and algorithms have been proposed for part retrieval. However, most of the existing methods are designed lbr mechanical parts, and can not be well worked for sheet metal part re- trieval. An approach to feature-based retrieval of sheet metal parts is presented. Firstly, the features frequently used in sheet metal part design are chosen as the ＂＇key words＂ in retrieval. Based on those features, a relative position model is built to express the different relationships of the features in 3D space. Secondly, a description method of the model is studied. With the descrip- tion method the relative position of features in sheet metal parts can be expressed by four location description matrices. Thirdly, based on the relative position model and location description matrices, the equivalent definition of relationships of two feature groups is given which is the basis to calculate the similarity of two sheet metal parts. Next, the tbrmula of retrieval algorithm for sheet metal parts is given. Finally, a prototype system is developed to test and verify the effectiveness of the retrieval method suggested. Experiments verify that the new method is able to meet the requirements of searching sheet metal parts and possesses potentials in practical application.

关键词： CAD sheet metal retrieval algorithm features search 3D model

EFFECTS OF COOLED EXTERNAL EXHAUST GAS RECIRCULATION ON DIESEL HOMOGENEOUS CHARGE COMPRESSION IGNITION ENGINE

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Chinese Journal of Mechanical Engineering 2007年第1期20卷 21-24页

作者： SHI lei CUI yi DENG Kangyao Key Laboratory for Power Machinery and Engineering of Ministry of Education Shanghai Jiaotong University Shanghai 200030 China

The effects of cooled external exhaust gas recirculation （EGR） on the combustion and emission performance of diesel fuel homogeneous charge compression ignition （HCCI） are studied. Homogeneous mixture is formed by injecting fuel in-cylinder in the negative valve overlap （NVO） period. So, the HCCI combustion which has low NOx and smoke emission is achieved. Cooled external EGR can delay the start of combustion effectively, which is very useful for high cetane fuel （diesel） HCCI, because these fuels can easily self-ignition, which makes the start of combustion more early. External EGR can avoid the knock combustion of HCCI at high load which means that the EGR can expand the high load limit. HCCI maintains low smoke emission at various EGR rate and various load compared with conventional diesel engine because there is no fuel-rich area in cylinder.

关键词： Homogeneous charge compression ignition (HCC1) Combustion Cooled exhaust gas recirculation (EGR) Emission

Advances in preoperative assessment of liver function

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Hepatobiliary & Pancreatic Diseases International 2014年第4期13卷 361-370页

作者： Peng-lei Ge Shun-Da Du yi-lei Mao Department of Liver Surgery Peking Union Medical College (PUMC) Hospital Chinese Academy of Medical Sciences and PUMC

BACKGROUND： Postoperative liver failure remains a lifethreatening complication. Preoperative evaluation of liver function is essential in reducing the complications after hepatectomy. However, it is difficult to accurately evaluate liver function before surgery because of the limitations of the liver function tests available. Recent advances in liver function tests improved the ability to assess liver function. The present review was to analyze these methods and their *** SOURCES： MEDLINE was searched using the terms of ＂liver function test＂, ＂liver function evaluation＂ and ＂galactosyl serum albumin＂. Relevant articles published in English and Chinese from 1961 to 2014 were ***： Although serological tests are used frequently in practice, they reflect the degree of total liver damage or function, not the remnant of liver function. Child-Pugh score and model for end-stage liver disease（MELD） score assess whole liver function, and are particularly useful in determining whether patients with hepatocellular carcinoma and cirrhosis are candidates for resection or transplantation, but cannot determine the safe extent or removal. The indocyanine green and other metabolic quantitative liver function tests can evaluate functional hepatocytes, making them more accurate in predicting liver function. Computed tomography（CT）volumetry can provide anatomic information on the remnant liver volume but not on functional volume. 99mTc-galactosyl serum albumin scintigraphy, combined with single photon emission computed tomography, CT and three-dimensional reconstruction, may be a better quantitative measure of liver function, especially of remnant liver ***： Tests used to evaluate liver functional reserve and to predict surgical risk have limitations. 99mTc-galactosylserum albumin scintigraphy, which can more accurately evaluate the whole and regional liver function, may be promising in predicting resection margins and risks of liver failure.

关键词： liver function test hepatectomy asialoglycoprotein galactosyl serum albumin

DISCRETIZATION APPROACH USING RAY-TESTING MODEL IN PARTING LINE AND PARTING SURFACE GENERATION

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Chinese Journal of Mechanical Engineering 2007年第1期20卷 47-54页

作者： HAN Jianwen JIAN Bin YAN Guangrong lei yi School of MechanicalEngineering ＆ Automation Beihang University Beijing 100083 China

Surface classification, 3D parting line, parting surface generation and demoldability analysis which is helpful to select optimal parting direction and optimal parting line are involved in auto-matic cavity design based on the my-testing model. A new ray-testing approach is presented to classify the part surfaces to core/cavity surfaces and undercut surfaces by automatic identifying the visibility of surfaces. A simple, direct and efficient algorithm to identify surface visibility is developed. The algorithm is robust and adapted to rather complicated geometry, so it is valuable in computer-aided mold design systems. To validate the efficiency of the approach, an experimental program is implemented. Case studies show that the approach is practical and valuable in automatic parting line and parting surface generation.

关键词： Visibility Ray-testing Surface classification Parting line Demoldability analysis

Influence of counteranions on catalytic ability of immobilized laccase in Cu-alginate matrices: Inhibition of chloride and activation of acetate

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Chinese Chemical Letters 2014年第7期25卷 983-988页

作者： Ting Pan Yao-Jin Sun Xiao-lei Wang Ting Shi yi-lei Zhao State Key Laboratory of Microbial Metabolism School of Life Sciences & BiotechnologyShanghai Jiao Tong University

Laccase is a promising oxidase with environmental applications, such as lignin degradation and chlorophenol detoxification. Laccase immobilization can significantly improve physiochemical stability and reusability compared to the free enzymes. In this work, anion effect was investigated in entrapment of Cu-alginate matrix with five types of anions, including perchlorate （ClO4）, nitrate （NO3）, sulfate （SO42 ）, chloride （Cl）, and acetate （CH3CO2-）. Accordingly, chloride inhibition and acetate activation were detected in the o-tolidine kinetic experiments, while effects of the other three anions were much smaller. Such counteranion effects were also observed in the laccase-catalyzed biodegradation of 2,4- dichlorophenol. The results indicated that counteranions in the enzyme immobilization process are crucial for catalytic capacity, probably due to the competition with the carboxylate groups in alginate. Our results also imply that these anions might coordinate the copper cations in laccase.

关键词： Counterion effect Cu-alginate matrix Laccase immobilization Enzyme activity

“PALPATION BY IMAGING”:MAGNETIC RESONANCE ELASTOGRAPHY

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Chinese Medical Sciences Journal 2006年第4期21卷 281-286页

作者： lei Xu Pei-yi Gao Imaging Center of Neuroscience Beijing Tiantan Hospital Capital University of Medical Sciences Beijing 100050

Elasticity is an important physical property of human tissues. There is a tremendous difference in elasticity between normal and pathological tissues. Noninvasive evaluation of the elasticity of human tissues would be valuable for clinical practice. Magnetic resonance elastography(MRE)is a recently developed noninvasive imaging technique that can directly visualize and quantitatively measure tissue elasticity. This article reviewed the MRE technique and its current status.

关键词： magnetic resonance imaging elasticity tissue characterization

Improved Z^(1/3) Law of Nuclear Charge Radius

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Communications in Theoretical Physics 2009年第1期51卷 123-125页

作者： lei yi-An ZHANG Zhen-Hua ZENG Jin-Yan School of Physics Peking University Beijing 100871 China

An improved Z^1/3 law of nuclear charge radius is presented. The comparison between the calculated and experimental nuclear charge radii now available shows that this new formula is better than the other conventional ... 详细信息

关键词： nuclear charge radius improved Z^1/3 law isospin dependence