检索结果-南通市图书馆

Two Monte Carlo-based simulators for imaging-system modeling and projection simulation of flat-panel X-ray source

Nuclear Science and Techniques 2024年第7期35卷 31-46页

作者： meng-Ke Qi Ting He Yi-Wen Zhou Jing Kang Zeng-Xiang Pan Song Kang Wang-jiang Wu Jun Chen Ling-Hong Zhou Yuan Xu School of Biomedical Engineering Southern Medical UniversityGuangzhou510515China State Key Laboratory of Optoelectronic Materials and Technologies Guangdong Province Key Laboratory of Display Material and TechnologySchool of Electronics and Information TechnologySun Yat-sen UniversityGuangzhou510275China department of Radiotherapy Guangdong Provincial People’s Hospital(Guangdong Academy of Medical Sciences)Southern Medical UniversityGuangzhou510515China

The advantages of a flat-panel X-ray source(FPXS)make it a promising candidate for imaging *** imaging-system modeling and projection simulation are critical for analyzing imaging performance and resolving overlapping projection issues in *** conventional analytical ray-tracing approach is limited by the number of patterns and is not applicable to FPXS-projection ***,the computation time of Monte Carlo(MC)simulation is independent of the size of the patterned arrays in *** study proposes two high-efficiency MC projection simulators for FPXS:a graphics processing unit(GPU)-based phase-space sampling MC(gPSMC)simulator and GPU-based fluence sampling MC(gFSMC)*** two simulators comprise three components:imaging-system modeling,photon initialization,and physical-interaction simulations in the ***-system modeling was performed by modeling the FPXS,imaging geometry,and *** gPSMC simulator samples the initial photons from the phase space,whereas the gFSMC simulator performs photon initialization from the calculated energy spectrum and fluence *** entire process of photon interaction with the geometry and arrival at the detector was simulated in parallel using multiple GPU kernels,and projections based on the two simulators were *** accuracies of the two simulators were evaluated by comparing them with the conventional analytical ray-tracing approach and acquired projections,and the efficiencies were evaluated by comparing the computation *** results of simulated and realistic experiments illustrate the accuracy and efficiency of the proposed gPSMC and gFSMC simulators in the projection calculation of various phantoms.

关键词： Flat-panel X-ray source(FPXS) Imaging-system modeling Projection simulation Monte Carlo-based simulators

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

AN INVERSE EIGENVALUE PROBLEM FOR JACOBI MATRICES

引用

Journal of Computational mathematics 2003年第5期21卷 569-584页

作者： Er-xiong jiang (department of {2., Shanghai university, Shanghai 2.0436, china) department of mathematics Shanghai University 上海 200436

Let T1,n be an n x n unreduced symmetric tridiagonal matrix with eigenvaluesand is an (n - 1) x (n - 1) submatrix by deleting the kth row and kth column, k = 1, 2.be the eigenvalues of T1,k andbe the eigenvalues of Tk+1,nA new inverse eigenvalues problem has put forward as follows: How do we construct anunreduced symmetric tridiagonal matrix T1,n, if we only know the spectral data: theeigenvalues of T1,n, the eigenvalues of Ti,k-1 and the eigenvalues of Tk+1,n?Namely if we only know the data: A1, A2. An,how do we find the matrix T1,n? A necessary and sufficient condition and an algorithm ofsolving such problem, are given in this paper.

关键词： Symmetric tridiagonal matrix Jacobi matrix Eigenvalue problem Inverse eigenvalue problem.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A fractal study for nucleate pool boiling heat transfer of nanofluids

引用

Science china(Physics,Mechanics & Astronomy) 2010年第1期53卷 30-37页

作者： XIAO BoQi 1 , jiang GuoPing 2.& CHEN LingXia 1 1 department of Physics and Electromechanical Engineering, Sanming {2., Sanming 365004, china 2.Earthquake Engineering Research Test Center, Guangzhou {2., Guangzhou 510405, china 1. department of Physics and Electromechanical Engineering Sanming University Sanming 365004 China2. Earthquake Engineering Research Test Center Guangzhou University Guangzhou 510405 China

In this paper, a fractal model for nucleate pool boiling heat transfer of nanofluids is developed based on the fractal distribution of nanoparticles and nucleation sites on boiling surfaces. The model shows the dependences of the heat flux on nanoparticle size and the nanoparticle volume fraction of the suspension, the fractal dimension of the nanoparticle and nucleation site, temperature of nanofluids and properties of fluids. The fractal model predictions show that the natural convection stage continues relatively longer in the case of nanofluids. The addition of nanoparticles causes a decrease of the pool nucleate boiling heat transfer. The nucleate pool boiling heat transfer coefficient is decreased by increasing particle concentration. An excellent agreement between the proposed model predictions and experimental data is found. The validity of the fractal model for nucleate pool boiling heat transfer is thus verified.

关键词： nanofluid nucleate pool boiling fractal heat transfer

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Quasisymmetric property for conjugacies between Anosov diffeomorphisms of the two-torus

引用

Science china mathematics 2010年第3期53卷 663-670页

作者： HU HuYi 1 & jiang YunPing 2. 1 department of {2., Michigan State university, East Lansing, MI 4882., USA 2.department of {2., the Graduate Center and Queens College of CUNY, Flushing, NY 11367, USA 1. department of mathematics Michigan State University East Lansing MI 48824 USA2. Department of Mathematics the Graduate Center and Queens College of CUNY Flushing NY 11367 USA

We prove that the restrictions of the conjugacy between two Anosov diffeomorphisms of the twotorus to the stable and unstable manifolds are quasisymmetric homeomorphisms.

关键词： quasisymmetry Anosov diffeomorphisms conjugacy Hlder condition Markov partition

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Synthesis and Lubrication of Phosphorylcholine Derivative

引用

Journal of Bionic Engineering 2010年第3期7卷 254-258页

作者： Zhenliang Qiao~1, Dangsheng Xiong~1, Lude Lu~2. Pengju jiang~2.1. {2. of Materials Science and Engineering, Nanjing university of Science and Technology, Nanjing 2.0094, P.R. china 2. School of Chemical Engineering, Nanjing university of Science and Technology, Nanjing 2.0094, P. R. china [a] department of Materials Science Engineering Nanjing University of Science Technology Nanjing 210094 P.R. China [b] School of Chemical Engineering Nanjing University of Science Technology Nanjing 210094 P. R. China

The monomer of phosphorylcholine derivative, O-(5-（2.methacryloxy）-3, 3-dimethyl-3-azapentyl)-O’-（ω-hydroxy-octyl）-phosphatequaternary ammonium salt, was designed and synthesized successfully. It was characterized by the spectra ofHNMR and Mass spectra （ESI+）, and every signal was assigned. Then the lubricating characteristics of the phosphorylcholinederivative were investigated on the tribological setup of ball-oh-flat. The Ultra-High Molecular Weight Polyethylene（UHMWPE） flat was rotated against a stainless steel ball with 6 mm diameter. The load was 2.3 N, which corresponded to amaximal Hertz contact pressure of 2. MPa. Water, phosphorylcholine derivative, and Acrylic Acid （AA） solution were used aslubricants, respectively. Compared with AA, the phosphorylcholine derivative shows significant lubrication. It can be stronglyhydrated under water due to the charged segment in chemical structure. The thick water layers within the chains serves asboundary lubricants, and this is thought to be the molecular origins of lubricating behavior.

关键词： artificial joint articular cartilage molecular lubrication mechanism phosphorylcholine synthesis UHMWPE

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Prevalence and clinical impact of sarcopenia in liver transplant recipients:A meta-analysis

引用

World Journal of Gastroenterology 2024年第8期30卷 956-968页

作者： Min-Jie jiang Mu-Chen Wu Zhong-Hui Duan Jing Wu Xiao-Tong Xu Juan Li Qing-Hua meng department of Hepatology Beijing You-An HospitalCapital Medical UniversityBeijing 100069China department of Emergency Beijing You-An HospitalCapital Medical UniversityBeijing 100069China

BACKGROUND The prevalence of sarcopenia in patients undergoing liver transplantation(LT)remains to be determined partly because of different diagnostic *** has recently been recognized as a new prognostic factor for predicting outcomes in LT *** To estimate the prevalence of sarcopenia and evaluate its clinical effect on LT *** This systematic search was conducted in PubMed,Web of Science,Embase,and Cochrane Library for original English-language articles that investigated the prevalence and influence of sarcopenia in patients undergoing LT from database inception to November 30,*** studies of the definition of sarcopenia that estimate sarcopenia prevalence and evaluate its effect on clinical outcomes and the risk of mortality were *** Twenty-five studies involving 7760 patients undergoing LT were *** pooled prevalence of sarcopenia in patients undergoing LT was 40.7%[95%confidence intervals(95%CI):32.1-49.6].The 1-,3-,and 5-year cumulative probab-ilities of post-LT survival in patients with preoperative sarcopenia were all lower than those without sarcopenia(P2.-2.07).Patients with preoperative sarcopenia had a longer intensive care unit stay,a high risk ratio of sepsis,and serious post-LT complications than those without *** Sarcopenia is prevalent in a substantial proportion of patients undergoing LT and is strongly and independently associated with higher a risk of mortality risk.

关键词： Sarcopenia Liver transplantation Mortality Clinical outcomes

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Variation of the Fe/Mn ratio of ferromanganese crusts from the Central North Pacific: implication for paleoclimate changes

引用

Progress in Natural Science:Materials International 2005年第6期15卷 530-537页

作者： LU Zunli1**, LING Hongfei1*, ZHOU Feng1, jiang Shaoyong1, CHEN Xiaoming1 and ZHOU Huaiyang2.1. State Key Laboratory for Mineral Deposits Research, {2. of Earth Sciences, Nanjing university, Nanjing 2.0093, china 2. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, china){2. of Earth & Environmental Science, university of Rochester State Key Laboratory for Mineral Deposits Research Department of Earth Sciences Nanjing University Nanjing 210093 China department of Earth & Environmental Science University of Rochester Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China

Contents of Fe, Mn and other elements in four ferromanganese crusts recovered from the central North Pacific are analyzed at high depth-resolution by electron microprobe for reconstructing factors controlling their deposition. Manganese (IV) in hydrogenetic ferromanganese crusts is mainly supplied as colloidal precipitates from the Oxygen Minimum Zone (OMZ), which concentrates high amounts of dissolved Mn (II). The iron is derived from carbonate dissolution and silicate particles of eolian dust. An increase in paleoproductivity during cooler climate would potentially lead to a decrease in Mn deposition due to enlargement of the OMZ which has a “temporary storage” effect for Mn. On the other hand, not affected by the OMZ, the iron entering the Fe-Mn crust would likely increase with the eolian dust input and surface productivity at glacial stages. As a result, the increasing Fe/Mn ratio should indicate a cooling climate. This is supported by the following observations. In the profile of the past 1 Ma, the variations of Fe/Mn ratio coincide with benthic oxygen isotope fluctuation in glacial-interglacial cycles. Three episodes with high Fe/Mn ratios, approximately at 2.6, 1.8 and 0.8 Ma, are detected within the past 3 Ma and coincide with major climate transitions and cooling events. The secular evolution pattern of Fe/Mn ratio in the Cenozoic is similar to the Pb isotope evolution which is mainly controlled by eolian dust and related to climate. The Fe/Mn evolution pattern is also broadly consistent with the global deep-sea oxygen isotope records. Therefore, Fe/Mn ratio recorded in the ferromanganese crusts may be a new proxy for climate change.

关键词： Fe/Mn ratio ferromanganese crust central North Pacific paleoclimate.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Effect of interfacial reactions on solid erosion of Al_(18) B_4O_(33) whisker-reinforced AC4C Al alloy matrix composites

引用

中国有色金属学会会刊：英文版 2000年第3期10卷 332-336页

作者： TU jiang ping(涂江平) 1, 3 , ZHU Li ping(朱丽萍) 2. meng Liang(孟亮) 1, LIU Mao sen(刘茂森) 1, M. Matsumura 3 1. {2. of Materials Science and Engineering, Zhejiang university, Hangzhou 31002., P.R.china 2. Zhejiang Technology Sc Zhejiang Univ Dept Mat Sci & Engn Hangzhou 310027 Peoples R China Zhejiang Technol Sch Bldg Mat Hangzhou 310014 Peoples R China Hiroshima Univ Dept Chem Engn Higashihiroshima 7398527 Japan

Solid erosion of as cast and treated 19.5%(volume fraction) Al 18 B 4O 33 whisker/AC4C Al composites was investigated at room temperature under steady state conditions. The results indicated that the interfacial reaction between the whisker and matrix alloy have an effect on the erosion characteristics of the composites. The erosion resistance of the composites with a strongly bonded whisker matrix interface and the higher whisker strength resulted from suitable reaction treatment can be improved at high impact angles and is the same as the as cast composites at low angle. For the composites after excessive reaction treatment, the weak and brittle interface fractures easily at small strains, and the whiskers with relative low strength and low hardness at the specimen surface can not effectively resist the microcutting or microploughing action, thus the composites exhibit reduced erosion resistance.

关键词： interfacial reactions solid erosion metal matrix composites

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Modeling and analyzing mixed communications in service-oriented trustworthy software

引用

Science china(Information Sciences) 2012年第12期55卷 2738-2756页

作者： jiang JianMin 1,ZHANG Shi 1,GONG Ping 1,HONG Zhong 1 & YUE HouGuang 2.1.department of Computer,Fujian Normal {2.,Fuzhou 350007,china 2.department of Computer,Shandong {2. of Finance and Economics,Jinan 2.0014,china 1. department of Computer Fujian Normal University Fuzhou 350007 China2. Department of Computer Shandong University of Finance and Economics Jinan 250014 China

Communication is an essential part of service-oriented trustworthy *** actual communication mechanism among services adopts asynchronous communications and supports broadcast ***,in order to achieve a better performance in analysis and verification,most existing formal languages rely on the strong hypothesis:the communication between services is *** this paper,we propose a novel model,which can model synchronous communications,asynchronous communications and broadcast communications in a uniform ***,we investigate the preservation problem of the weak termination and deadlocks of a composite service under the hierarchical communication models.

关键词： communication service composition message dependency deadlock

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Investigating the interaction between umami peptides and umami receptor T1R1/T1R3-VFT: a computational approach

引用

Food Science and Human Wellness 2024年

作者： Hengli meng Zhiyong Cui Yingqiu Li Yanyang Yu Shui jiang Yuan Liu department of Food Science & Technology， School of Agriculture and Biology， Shanghai Shanghai Jiao Tong university Secondary College of Cereals and Tourism， Guangxi Vocational College of Technology and Business

The study of ligand-receptor interactions is of great significance in food flavor perception. In this study， a computer simulation method was used to investigate the mechanism of interaction between umami peptides and T1R1/T1R3-VFT receptor. The binding site， conformational changes， and binding free energy between umami peptides and T1R1/T1R3-VFT were analyzed through molecular modeling， molecular docking， and molecular dynamics simulations. The receptor model constructed using AlphaFold2.has the best rationality. The molecular docking results showed that umami peptides primarily bound to T1R1-VFT through hydrogen bonding， with key binding residues such as 149THR， 151ARG， and 108ASP. The binding of umami peptides led to a more stable complex system， and the positively charged amino acids contributed positively to the overall binding free energy. This study provides theoretical support for the development of a better understanding of the interaction between umami substances and the umami receptor.

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：