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Progress of gastric cancer etiology:N-nitrosamides in the 1990s

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World Journal of Gastroenterology 2000年第4期6卷 613-618页

作者： Da Jun Deng Laboratory of Cancer Etiology,beijing Medical university School of Oncology& beijing Institute for Cancer Research,{3.,China 北京医科大学北京

Stomach carcinoma is still the leading cause of cancer death in China and the second one in the world. Its possible causes include: A) chemical factors such as intragastric formation of N-nitroso compounds (NOC) and high salt intake; B ) biological factors such as infection of Helicobacter pylori and biotoxins intake; and C ) nutritional factors such as deficiency of vitamin C, selenium, and other antioxidants. Nitrogenous precursors of NOC, e.g., alkylamines, alkylureas, alkylguanidines, and alkylamides, occur widely in nature and potential nitrosating agents, e.g., nitrite (NO2-) and NOx (the gaseous oxides of nitrogen ) are similarly widespread. Relationship between exposure to NOC and causes of human cancer was investigated extensively ten years ago. Results indicated that the exposures of NOC might contribute to the occurrences of malignancy in the upper digestive tracts including stomachs. It was also observed that both high salt intake and deficiency of some micronutrients enhanced NOC-induced carcinogenicity. Recent studies show that infection of H. pylori can lead to atrophic gastritis and achlorhydria, and promote endogenous formation of NOC indirectly[1] . Much attention has been paid to stomach cancer and NOC regarding the characterization of natural N-nitrosamides in human environment in the 1990s.

关键词： stomach neoplasms/etiology nitroso compounds nitrosamides/nitrosourea epidemiology chromatography liquid microorganisms

EXISTENCE OF FIAT TYPE MINIMAL SURFACES WITH 7 ENDSIN R~3

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中国科学院大学学报 1999年第2期 89-94页

作者： Peng Chiakui Xiao Liang (Department of Mathematics,graduate School of USTC,beijing 10003.)

In this paper,the flat type minimal surfaces in R 3.are discussed and the existence of flat type minimal surfaces with 7 ends in R 3.is proved.

关键词： flat type minimal surface Weierstrass representation

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压裂方案经济优化的智能专家系统研究

石油学报 2004年第1期25卷 66-69页

作者：蒋廷学汪永利丁云宏孙平许泽君中国石油勘探开发研究院廊坊分院中国地质大学北京100083 中国石油华北油田分公司勘探部成都理工大学四川成都610000

初步研究并建立了压裂方案经济优化的智能专家系统 ,其核心是遗传算法在压裂方案经济优选中的应用。该算法的突出特点是采用随机生成的方法 ,先形成几十个甚至几百个待选压裂方案 (每个压裂方案包含的各种设计参数各不相同 ) ,然后 ,综... 详细信息

初步研究并建立了压裂方案经济优化的智能专家系统 ,其核心是遗传算法在压裂方案经济优选中的应用。该算法的突出特点是采用随机生成的方法 ,先形成几十个甚至几百个待选压裂方案 (每个压裂方案包含的各种设计参数各不相同 ) ,然后 ,综合应用杂交和变异两种方法对诸压裂方案包括的诸多设计参数进行系统优化 ,经过多代遗传和变异后 ,最终可形成按经济净现值大小排序的压裂方案系列 ,从中可优选出最佳方案。此外 ,在智能专家系统中考虑到油价和利率在特定范围内的随机波动 ,因而是一个符合实际的理想模型。经现场压裂施工验证 ,取得了比常规压裂优化方法更为满意的效果。

关键词：专家系统遗传算法压裂方案经济优化杂交变异

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法律论证中的融贯论

法制与社会发展 2006年第2期12卷 117-128页

作者：蔡琳中国社会科学院研究生院北京100102

法律论证中的融贯论具有两个基本特性,即逻辑一致性以及信念之间的相互支持关系。法律论证中的融贯论在于回答因融贯本身所存在的责难而涉及越来越广泛的领域,它不仅仅是一种方法选择, 也是一种法律理论。其统一以法律、道德、政治为核... 详细信息

法律论证中的融贯论具有两个基本特性,即逻辑一致性以及信念之间的相互支持关系。法律论证中的融贯论在于回答因融贯本身所存在的责难而涉及越来越广泛的领域,它不仅仅是一种方法选择, 也是一种法律理论。其统一以法律、道德、政治为核心而形成融贯的体系。

关键词：融贯法律论证局部融贯论整全融贯论

Formation of nanotubes and secondary assemblies of cyclodextrins induced by BBOT

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Science China Chemistry 2010年第9期53卷 2019-2025页

作者： ZHANG JingJing,SHEN XingHai,WU AiHua,ZHANG ChunFen,CHEN QingDe & GAO HongCheng beijing National Laboratory for Molecular sciences Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science College of Chemistry and Molecular Engineering,Peking university,beijing 100871,China 1. beijing National Laboratory for Molecular sciences Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

The study of cyclodextrin nanotubes is a significant topic among the self-assembly behaviors of *** report herein the interaction of 2,5-bis(5'-tert-butyl-2-benzoxazoyl)thiophene(BBOT) with α-,β-,γ-cyclodextrins(CDs).It has been discovered that the reaction patterns of BBOT with CDs are remarkably different.α-CD forms a simple inclusion complex with BBOT in a stoichiometry of 1:2(guest:host).β-CD forms a 1:1 inclusion complex with BBOT at its low *** higher concentration of BBOT,the nanotube and secondary assembly of β-CD are *** for γ-CD,the nanotube and secondary assembly are formed within the whole concentration range of BBOT *** structure of γ-CD nanotubes is different from that of β-CD nanotubes to a certain extent.

关键词： BBOT cyclodextrin nanotube secondary assembly

柴西地区尕斯断陷同生逆断裂构造特征与形成演化

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石油与天然气地质 2004年第6期25卷 634-638页

作者：丁文龙王燮培李衍达郑求根清华大学北京100084 中国地质大学湖北武汉430074 中国石化无锡实验地质研究所江苏无锡214151

柴达木盆地西部尕斯断陷逆断裂和褶皱构造发育 ,褶皱与断裂紧密伴生 ,断裂位于背斜构造的一侧或两侧 ,各构造层高点上下铅直叠合。大多数断裂对沉积具有明显控制作用 ,尕斯断陷北西西向区域性同生逆断裂控制着局部沉积凹陷(生油凹陷 )... 详细信息

柴达木盆地西部尕斯断陷逆断裂和褶皱构造发育 ,褶皱与断裂紧密伴生 ,断裂位于背斜构造的一侧或两侧 ,各构造层高点上下铅直叠合。大多数断裂对沉积具有明显控制作用 ,尕斯断陷北西西向区域性同生逆断裂控制着局部沉积凹陷(生油凹陷 )的分布和范围 ,沉积中心位于断裂下降盘附近 ;而规模较小的同生逆断裂主要发育在凹陷或凸起内部 ,控制着局部构造圈闭的形成和发展。断裂与背斜构造发育不同期 ,断裂形成早 ,为边沉积边逆冲的基底同沉积断裂。背斜构造形成时间较晚 ,为第三纪晚期挤压或压扭性构造应力作用所致。背斜构造在中新世早期以后才显示出顶薄翼厚。

关键词：尕斯断陷基底卷入型同生逆断裂背斜构造生长指数同沉积性

Vibration velocity and frequency of underwater short-hole blasting

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Journal of university of Science and Technology beijing 2002年第4期9卷 245-248页

作者： Jianzhou Wang, Yalun Yu, and Zhiping LiCivil and Environmental Engineering School, university of Science and Technology beijing, beijing 100083. China Civil and Environmental Engineering School University of Science and Technology Beijing Beijing 100083 China

Based on the measuring data of underwater blasting vibration and theregression analysis results of these data, two formulae usually used of blasting vibration velocitywere compared. Factors that can affect blasting vibration and frequency were summarized andanalyzed. It is thought that the effect of the number of freedom face and burden direction onblasting vibration should be considered during blasting design. Based on the relevant researchresults and the regression results of these data, a formula to calculate under water blastingfrequency was put forward.

关键词： underwater blasting blasting vibration velocity frequency

SYNTHESIS AND BIOTECHNOLOGICAL APPLICATIONS OF VINYL POLYMERINORGANIC HYBRID AND MESOPOROUS MATERIALS

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Chinese Journal of Polymer Science 2000年第1期18卷 1-7页

作者： Yen Wei Kun-yuan Qiu Department of Chemistry, Drexel university, Philadelphia, Pennsylvania 19104. USA Department of Polymer Science and Engineering, Peking university, beijing 100871, China Drexel Univ Dept Chem Philadelphia PA 19104 USA Peking Univ Dept Polymer Sci & Engn Beijing 100871 Peoples R China

We describe the sol-gel synthesis of a new family of organic-inorganic hybrid materials, in which various vinyl polymers are covalently bonded to and uniformly distributed in inorganic oxide matrices. The materials can be tailored to have both good toughness and hardness while maintaining excellent optical transparency. Doping the sol-gel metal oxides with optically active compounds such as D-glucose results in new optical rotatory composite materials. Removal of the dopant compounds from the composites affords mesoporous oxide materials; which represents a new, nonsurfactant-templated route to mesoporous molecular sieves. We have successfully immobilized a series of enzymes and other bioactive agents in mesoporous materials. Catalytical activities of the enzyme encapsulated in mesoporous materials were found to be much higher than those encapsulated in microporous materials.

关键词： vinyl polymer-inorganic hybrid materials mesoporous materials sol-gel process biotech-nological applications

Noise helped manifestation of intrinsic frequency:A case study in the mesoscopic hormone signaling system

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Progress in Natural Science:Materials International 2009年第10期19卷 1209-1214页

作者： Lin Ji a,,Yuanyuan Zhang a,Xiufeng Lang b,Wenxiang Hu a,Qianshu Li c a Department of Chemistry,Capital Normal university,beijing 10004.,China b School of Science,beijing university of Aeronautics and Astronautics,beijing 100191,China c The Institute for Chemical Physics,beijing Institute of Technology,beijing 100081,China [a]Department of Chemistry Capital Normal University Beijing 100048 China [b]School of Science Beijing University of Aeronautics and Astronautics Beijing 100191 China [c]The Institute for Chemical Physics Beijing Institute of Technology Beijing 100081 China

The selective sustainment of nonlinear systems to signals is of great significance to signal transduction in living *** take hormone signaling as an example,and investigate the sustainment of internal and external *** results prove that signals with "intrinsic frequency",no matter if it is noise induced or external injected,can be selectively sustained by exploiting internal and/or external *** the internal and external noise can optimize the noise-induced signals,and the optimization is rather robust to the disturbance of external signals with other *** results are of significance for weak signal detection and transduction in the presence of external signals.

关键词： Noise Intrinsic frequency Mesoscopic system