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Research on a Monte Carlo global variance reduction method based on an automatic importance sampling method

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Nuclear Science and Techniques 2024年第5期35卷 200-215页

作者： Yi-sheng Hao Zhen Wu shen-shen gao Rui Qiu Hui Zhang Jun-Li Li Department of Engineering Physics Tsinghua UniversityBeijing 100084China Key Laboratory of Particle and Radiation Imaging of Ministry of Education Beijing 100084China Nuctech Company Limited Beijing 100084China

Global variance reduction is a bottleneck in Monte Carlo shielding *** global variance reduction problem requires that the statistical error of the entire space is *** study proposed a grid-AIS method for the global variance reduction problem based on the AIS method,which was implemented in the Monte Carlo program *** proposed method was validated using the VENUS-Ⅲ international benchmark problem and a self-shielding calculation *** results from the VENUS-Ⅲ benchmark problem showed that the grid-AIS method achieved a significant reduction in the variance of the statistical errors of the MESH grids,decreasing from 1.08×10^(-2) to 3.84×10^(-3),representing a 64.00% *** demonstrates that the grid-AIS method is effective in addressing global *** results of the selfshielding calculation demonstrate that the grid-AIS method produced accurate computational ***,the grid-AIS method exhibited a computational efficiency approximately one order of magnitude higher than that of the AIS method and approximately two orders of magnitude higher than that of the conventional Monte Carlo method.

关键词： Monte Carlo Global variance reduction Reactor shielding Automatic importance sampling

Delay-constrained sleeping mechanism for energy saving in cache-aided ultra-dense network

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Science China(Information Sciences) 2019年第8期62卷 131-144页

作者： Pei LI Shulei GONG shen gao Yaoyue HU Zhiwen PAN Xiaohu YOU National Mobile Communications Research Laboratory Southeast University Institute of Space-Terrestrial Intelligent Networks School of Electronic Science and EngineeringNanjing University China Mobile Group Jiangsu Co. Ltd.

We investigate an energy-saving sleeping mechanism in a cache-aided ultra-dense network(UDN)with delay constraints. As in existing works, we consider the video and file contents of the UDN. The video contents are cached at and delivered by a small-cell base-station(sBS). The cache-aided sBS cooperates with a macro-cell base-station(mBS) to service the file contents. The optimal sleeping strategy that conserves energy under the delay constraint is formulated as an energy-consumption minimization problem under the network stability condition with a guaranteed delay constraint. To find its solution, the minimization problem is transformed into a joint optimization problem of energy consumption and delay by the Lyapunov technique.A delay-constrained sleeping algorithm is proposed, and its effectiveness is confirmed by the numerical results of a simulation study. A tradeoff between energy consumption and delay, achieved by adjusting the weighting factor in the cache-aided UDN, is also demonstrated.

关键词： ultra-dense networks sleeping mechanism mean delay caching strategy energy saving

CMGC: a CAD to Monte Carlo geometry conversion code

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Nuclear Science and Techniques 2020年第8期31卷 104-115页

作者： Xin Wang Jun-Li Li Zhen Wu shen-shen gao Rui Qiu Li Deng Gang Li Institute of Applied Physics and Computational Mathematics Beijing 100088China CAEP Software Center for High Performance Numerical Simulation Beijing 100088China Department of Engineering Physics Tsinghua UniversityBeijing 100084China Nuctech Company Limited Beijing 100084China

Automatic conversion from a computer-aided design(CAD) model to Monte Carlo geometry is one of the most effective methods for large-scale and detailed Monte Carlo modeling. The CAD to Monte Carlo geometry converter(CMGC) is a newly developed conversion code based on the boundary representation to constructive solid geometry(BRep→CSG) conversion method. The goal of the conversion process in the CMGC is to generate an appropriate CSG representation to achieve highly efficient Monte Carlo simulations. We designed a complete solid decomposition scheme to split a complex solid into as few nonoverlapping simple sub-solids as possible. In the complete solid decomposition scheme, the complex solid is successively split by so-called direct, indirect, and auxiliary splitting surfaces. We defined the splitting edge and designed a method for determining the direct splitting surface based on the splitting edge, then provided a method for determining indirect and auxiliary splitting surfaces based on solid vertices. Only the sub-solids that contain concave boundary faces need to be supplemented with auxiliary surfaces because the solid is completely decomposed, which will reduce the redundancy in the CSG expression. After decomposition, these sub-solids are located on only one side of their natural and auxiliary surfaces;thus, each sub-solid can be described by the intersections of a series of half-spaces or geometrical primitives. The CMGC has a friendly graphical user interface and can convert a CAD model into geometry input files for several Monte Carlo codes. The reliability of the CMGC was evaluated by converting several complex models and calculating the relative volume errors. Moreover, JMCT was used to test the efficiency of the Monte Carlo simulation. The results showed that the converted models performed well in particle transport calculations.

关键词： Monte Carlo CAD Geometry converter Complete solid decomposition

Study on the application of active balancing device to solve the vibration problem for the rotor with bending fault

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High Technology Letters 2006年第3期12卷 225-230页

作者：何立东 shen Wei gao Jinji Zhou Weihua Beijing University of Chemical Tectmology Beijing 100029 P.R. China

The rotor with bending faults that occurrs on the rotating machinery usually vibrates seriously. This paper investigates to apply the active balancing device on a flexible rotor with bending faults to solve the vibration problem. Two problems are studied by finite element method firstly： Where the balance actuator is fixed on the shaft and how much the balancing capacity of the active balancing device is needed. The experiment is then carried out on the test rig, which consists of a flexible rotor with bending faults. The test results indicate that the bending rotor peak vibration response can be decreased from 550~m to 40~tm below by using the active balancing device. The peak vibration response decreases approximately by 93 %. The synchronous vibration due to the rotor bending faults can be controlled effectively by using ac- tive balancing device. The active balancing device is especially adapted to solve the problem caused by thermal distortion with time-variation and randomness, which is varied with working conditions, thus it has good practical value in practice.

关键词： active balancing bending turbomachinery vibration FEA

Overexpression of decoy receptor 3 in hepatocellular carcinoma and its association with resistance to Fas ligand-mediated apoptosis

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World Journal of Gastroenterology 2005年第38期11卷 5926-5930页

作者： Hong-Wei shen Shun-Liang gao Yu-Lian Wu Shu-You Peng Department of Surgery 2^nd Affiliated Hospital of Medical CollegeZhejiang University Hangzhou 310009 Zhejiang Province China

AIM： To characterize the expression and genomic amplification of decoy receptor 3 （DcR3） in hepatocellular carcinoma （HCC） and to evaluate the role of DcR3 in apoptosis.METHODS： We examined 48 cases of HCC for DcR3 expression by RT-PCR and DcR3 gene amplification by quantitative genomic PCR. DcR3 protein was detected by immunohistochemistry. Terminal deoxynucleotidyl transferase-mediated dUTP digoxigenin nick and labeling （TUNEL） was used to identify the apoptosis cells in tissues. Primary hepatoma cell culture and MTT test were used to evaluate the protection against FasL- and chemicalinduced apoptosis by DcR3 expression. RESULTS： DcR3 mRNA overexpression was detected in 60% HCC （29/48） patients. The occurrence of HCC was not associated with amplification of the gene. One sample base substitution was found in three sites as a sequence in Genbank. The expression of DcR3 in HCC was associated with the apoptotic index （0.067±0.04 vs 0.209±0.12, P〈0. 01）, size of mass, stage, and infiltration or metastasis （41.2% vs71.0%, 40% vs75%, 51.8% vs84.6%, P〈0. 05）. DcR3 expression could protect hepatoma cells against apoptosis induced by FasL, but not by chemicals. CONCLUSION： These data suggest that in addition to gene amplification there may be another mechanism underlying DcR3 overexpression. The effect of overexpression of DcR3 on the apoptosis of cancer cells may have direct therapeutic implications for the management of HCC.

关键词： DcR3 Hepatocellular carcinoma Apoptosis

An efficient ionic liquid supported divergent assembly of 3,6-branched glucosamine-containing pentasaccharide

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Chinese Chemical Letters 2014年第12期25卷 1525-1530页

作者： Ze-shen gao sheng Sun Wei Li Qing Ma Qing Li Zhong-Jun Li The State Key Laboratory of Natural and Biomimetic Drugs School of Pharmaceutical SciencesPeking University

We utilized the glycosyl acceptor tagging method with ionic liquid support for synthesis of the core segment of Clostridium botulinum C2 toxin ligand through a divergent synthetic strategy without chromatographic *** total yield was 57.1% and the reaction was completed in 10 *** efficient ionic liquid supported glycosylation and purification procedure was applied for the synthesis of branched glucosamine-containing oligosaccharides for the first time,which expanded the scope of ionic liquid supported synthesis of biologically important oligosaccharides.

关键词： Ionic liquid Oligosaccharide Rapid assembling

Influence of La and RE on the Underside Shrinkage of ZA27 Alloy

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Journal of Rare Earths 1999年第2期17卷 47-51页

作者： Chen Yungui, Tu Mingjing, shen Baoluo, gao shengji (Department of Metal Materials, Sichuan University, Chengdu 610065, China) Department of Metal Materials Sichuan University Chengdu 610065 China

The effect of pure La and mischmetal(RE) on underside shrinkage of ZA27 alloy with cooling rate of 32 min-1 was investigated. The results show that the volumes of the underside shrinkage and the total shrinkage(underside shrinkage plus internal shrinkage) of the alloy decrease as the content of La or RE increases. When the contents of La and RE exceed 03%04%(mass fraction) respectively, the underside shrinkage is eliminated and the internal shrinkage moves upwards gradually. The mechanism that the underside shrinkage is eliminated is the falling of La and RE compounds and their accumulation on the bottom of the ZA27 alloy sample. Since La and RE can not effectively prevent phases(Al base solid solution) in the alloy from rising, the internal shrinkage is still close to the bottom of the ZA27 sample.

关键词： Rare earths Lanthanum Zinc base alloy Underside shrinkage

Effects of Micronutrients on Oxidative Stress and Islet Function in Type 1 Diabetes Mellitus Rats:Relationships to Th2 Type Cytokines,Interleukin-4,and Interluekin-10

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Chemical Research in Chinese Universities 2007年第6期23卷 701-704页

作者： ZHANG Gui-zhen LI Mei-hua SONG Yang LIU Ting gao shen SUN Ying Department of Central Research The Third Clinical College Jilin University Changchun 130033 P. R. China Department of Allergy ＆ Clinical Immunology Faculty of Medicine Imperial College School National Heart ＆ Lung Institute Dovehouse Street London SW3 6LY UK

To observe the effects of the micronutrients on oxidative and autoimmune destruction of islets so as to prevent a person from the onset and development of type 1 Diabetes Mellitus （T1DM）, the interleukin-4 and interleukin-10 expressions of lymphocytes in peripheral blood and spleen of T1DM rats were determined by flow cytometry. GSH-Px activity and MDA level in the rats＇ pancreas were measured using biochemical methods. The insulin contents in serum and β cell insulin secret storage were tested by RIA and IHC, respectively. There was an increase in the percentages of IL-4 and IL-10 positive lymphocytes in the peripheral blood and spleen of the groups of rats supplemented with various combinations of micronutrients（p 〈0.01 and p 〈0.05, respectively） ; the blood glucose concentration decreased （p 〈 0. 05 ） ; both the functional β cell in islets and the insulin content in pancreatic tissue increased （p 〈 0. 05 and p 〈0. 01 ） ; the GSH-Px activity and MDA level of pancreas in the rats enhanced and decreased respectively（p 〈0. 01 and p 〈 0. 05）. The results suggest that micronutrients may alleviate the islet lesions by upregulating the expressions of IL-4 and IL-10 and lowering oxidative stress in diabetic rats .

关键词： Immanohistochemistry Oxidative stress Micronutrients T1 DM Interleukin-4 Interluekin-10

Unveil the Redox Evolution of Ore-forming Fluids using Sulfur Isotope:A Case Study of the Zhengguang Intermediate Sulfidation Epithermal Au-Zn Deposit,NE China

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Acta Geologica Sinica(English Edition) 2023年第5期97卷 1462-1474页

作者： WANG Le gao shen QIN Kezhang SONG Guoxue HAN Ri SU Shiqiang GUO Jihai PANG Xuyong LI Guangming Key Laboratory of Mineral Resources Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Department of Earth Sciences University of GenevaGeneva 1205Switzerland School of Earth Science and Resources China University of GeosciencesBeijing 100083China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 101408China Heilongjiang Baoshan Mining Co. Ltd.HeiheHeilongjiang 164300China Institute of Mineral Resources Chinese Academy of Geological SciencesBeijing 100037China

Oxygen fugacity(fO_(2))is a key intensity variable during the entire magmatic-hydrothermal mineralization *** redox state and its variations between different stages of the ore-forming fluids of intermediate sulfidation epithermal deposits are rarely deciphered due to the lack of appropriate approaches to determine fO_(2)of the ***,we reported theδ^(34)S of the sulfides from three different stages(stageⅠ,Ⅱ,Ⅲ)of Zhengguang,an Early Ordovician Au-rich intermediate sulfidation(IS)epithermal deposit,to decipher the redox evolution of the ore-forming *** increasingδ^(34)S values from stageⅠpyrite(pyl,average-2.6‰)through py2(average-1.9‰)to py3(average-0.2‰)indicates a decrease of the oxygen fugacity of the ore-forming fluids.A compilation ofδ^(34)S values of sulfides from two subtypes of IS deposits(Au-rich and Ag-rich)from NE China shows that theδ^(34)S values of sulfides from Au-rich IS deposits are systematically lighter than those of Ag-rich IS Ag-Pb-Zn deposit,indicating the ore-forming fluids of the former are more oxidized than the *** highlight that sulfur isotopic composition of hypogene sulfides is an efficacious proxy to fingerprint the oxygen fugacity fluctuations of epithermal deposits and could potentially be used to distinguish the subtypes of IS deposits.

关键词： intermediate sulfidation epithermal sulfur isotope ore-forming fluids oxygen fugacity Zhengguang