检索结果-南通市图书馆

Fabrication of Thin Graphene Layers on a Stacked 6H-SiC Surface in a Graphite Enclosure

同方期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2013年第1期30卷 208-211页

作者： DENG Peng-Fei LEI Tian-Min LU Jin-Jun liu fu-yan ZHANG Yu-Ming GUO Hui ZHANG Yi-Men WANG Yue-Hu TANG Xiao-yan School of Technical Physics Xidian UniversityXi'an 710071 School of Microelectronics Xidian UniversityXi'an 710071 State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000

Thin and homogeneous epitaxial graphene(EG)layers on a 6H-SiC(0001)substrate are fabricated and they cover the whole substrate(10×10 mm^(2)).The sample surface is capped by another 6H-SiC(0001)wafer in a graphite enclosure to form a relatively high Si partial pressure between them,which significantly reduces the extremely high growth rate of *** structure and morphology of the EG layers are investigated by Raman spectroscopy,atomic force microscopy and field-emission scanning electronic *** results are compared with an uncapped sample surface,and reveal the obvious existence of ridges on the surface of the EG,and show that capping is indeed beneficial to obtain homogeneous graphene.

关键词： closure surface Surface

Effect of endogenous hydrogen sulfide on oxidative stress in oleic acid-induced acute lung injury in rats

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2011年第21期124卷 3476-3480页

作者： WANG Cong WANG Hai-ying liu Zhi-wei fu yan ZHAO Bin Department of Emergency Medicine Beijing Jishuitan Hospital Beijing 100035 China

Background Acute lung injury （ALl） is a common critical disease in emergency care. Oxidative stress plays an important role in the pathogenesis of ALl. Endogenous hydrogen sulfide （H2S） can inhibit oxidative stress in rat gastric mucosal epithelium. In this study, we examined the possible role of H2S in regulation of the oxidative stress in oleic acid-induced acute lung injury in rats. Methods The rat model of ALl was induced by intra-tail vein injection of oleic acid （CA）. NariS solution was injected intraperitoneally before CA injection as an CA＋NariS group. A semi-quantitative histological index of quantitative assessment of lung injury was calculated. The levels of superoxide dismutase （SOD）, glutathione （GSH） and malondialdehyde （MDA） in plasma and lung tissue were detected with ELISA. The levels of H2S content in lung tissue were detected with an ion meter. Results Compared with the control group, the level of H2S in lung tissue was significantly decreased, and the level of SOD and GSH were decreased but the level of MDA was increased in plasma and lung tissue in rats with ALl. NariS lessened the ALl in association with an increase in the level of H2S in lung tissue, a decrease in the level of MDA but an increase in SOD and GSH levels in plasma and lung tissues. Conclusion Endogenous H2S could inhibit the oxidative stress in lung tissue in oleic acid-induced acute lung injury in rats.

关键词： acute lung injury hydrogen sulfide oxidative stress

在线全文

学校读者我要写书评

暂无评论

非饱和黏土状态相关本构模型的数值实现

岩土力学 2017年第10期38卷 2799-2808页

作者：李舰韦昌富刘艳北京交通大学土建学院北京100044 中国科学院武汉岩土力学研究所岩土力学与工程国家重点试验室湖北武汉430071

基于双重塑性机制,即剪切滑移和加载湿陷机制,及毛细滞回和变形间的耦合作用,提出了一个适用于非饱和黏土的状态相关本构模型。建立了该模型的隐式积分算法,并处理了双重固相屈服面交点处的应力积分问题。考虑了吸力与应力间的关系,推... 详细信息

基于双重塑性机制,即剪切滑移和加载湿陷机制,及毛细滞回和变形间的耦合作用,提出了一个适用于非饱和黏土的状态相关本构模型。建立了该模型的隐式积分算法,并处理了双重固相屈服面交点处的应力积分问题。考虑了吸力与应力间的关系,推导了本构关系的一致性切线模量。最后,利用该模型预测了一组非饱和黏土的三轴试验,以此反映模型的描述能力;对比了不同应变步长下应变控制试验的计算结果,并以此验证算法的收敛性和准确性;利用有限元程序平台U_DYSAC2计算了二维情况下非饱和土地区地基固结问题,从而验证所得一致性切线模量的有效性。

关键词：非饱和土状态相关本构模型隐式积分算法一致性切线模量

在线全文

学校读者我要写书评

暂无评论

一种提高微内核效率的有效方法

上海交通大学学报 2000年第7期34卷 952-955,959页

作者：刘福岩尤晋元上海交通大学计算机科学及工程系上海200030

提出了一种提高微内核操作系统效率的方法 ,该方法通过在操作系统中实现单地址空间、操作系统内核程序和用户程序在一个处理机状态下运行以及利用 capability实施对资源和特权指令的保护 ,使得当客户进程通过进程通信访问服务器提供的... 详细信息

提出了一种提高微内核操作系统效率的方法 ,该方法通过在操作系统中实现单地址空间、操作系统内核程序和用户程序在一个处理机状态下运行以及利用 capability实施对资源和特权指令的保护 ,使得当客户进程通过进程通信访问服务器提供的服务时 ,不需要执行进程空间的切换和CPU状态的切换。

关键词：操作系统微内核单地址空间进程空间 CPU 切换

Discovery of a new family member of arsenic–vanadium polyoxometalates with high catalytic performance for one-pot coupling of CO2, epoxides and amines

在线全文

学校读者我要写书评

暂无评论

Tungsten 2025年第1期7卷 80-87页

作者： Fang-Qian Wang Yin Zhang Wei-Wei Wang Mei-Qian fu Hong-Bing Mo Wei-Dong Yu Chao liu Jun yan College of Chemistry and Chemical Engineering Central South University Junior Education Department Changsha Normal University School of Science Hunan University of Technology and Business

Arsenic-vanadium polyoxometalates（POMs） represent a family of tremendous potential catalysts owing to their peculiar physical and chemical *** in CO2conversion,using POMs to catalyze the conversion of CO2and epoxide into chemical intermediates is the research ***,A new family number of arsenic-vanadium POMs,[N（CH3）4]4[As8V12O38（H2O）]·2H2O({As8V12O38}),was reported and characterized by single-crystal X-ray diffraction,fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,*** from other allotropicity,{As8V12O38}shows a different structure pattern with an I-43d *** obtained {As8V12O38} was employed as a catalyst for the *** initial catalytic reaction confirmed that {As8V12O38} can catalyze the formation of epoxy carbonate by using 1.01 kPa CO2and epoxide at 70℃.furtherly,when added amine in the catalytic system,oxazolidinone could be obtained by high yields,which provides an efficient way to convert CO2into profitable ***,a possible catalytic reaction mechanism was proposed by using different characterization analyses.{As8V12O38} first catalyzes the epoxide and CO2to form an epoxy carbonate and then catalyzes epoxy carbonate and benzylamine into oxazolidinone.

关键词： Arsenic CO2 conversion Oxazolidinone Polyoxometalates Vanadium

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

存储系统的层次性与进程数据存储模型

计算机研究与发展 2000年第11期37卷 1367-1374页

作者：刘福岩尤晋元上海交通大学计算机科学与工程系

计算机系统的各种存储部件 ,包括寄存器、cache、内存、外存 ,被组织成一个层次性的存储结构 .传统操作系统分别在内存和外存这两个层次上为用户构造了两种数据存储模型 :进程逻辑空间和文件 .应该在存储层次的最外层——外存直接为用... 详细信息

计算机系统的各种存储部件 ,包括寄存器、cache、内存、外存 ,被组织成一个层次性的存储结构 .传统操作系统分别在内存和外存这两个层次上为用户构造了两种数据存储模型 :进程逻辑空间和文件 .应该在存储层次的最外层——外存直接为用户构造进程数据存储模型——文件 ,把全部内存作为进程访问外存的缓冲 ,取消了进程逻辑空间的概念 ,实现指令对文件的直接寻址 ,使进程直接在文件上运行 .基于以上思想 ,提出了一个操作系统模型 ,介绍了该模型的结构及其一个实现原型 ,并对其性能进行了测试和评价 ,最后讨论了该操作系统具有的优点及其存在的问题 .

关键词：存储系统进程数据存储模型操作系统

在线全文

学校读者我要写书评

暂无评论

论荀子与儒家礼乐观的情感论转向

湖南师范大学社会科学学报 2014年第1期43卷 106-111页

作者：刘延福河南理工大学河南焦作454003

荀子在继承了儒家传统礼乐思想的基础上,对其进行了历史性地改造,第一次比较深入全面地探讨了礼乐思想的不同内涵与作用,提出并论述了"乐合同,礼别异"的观点。他认为,强制性原则的礼与调和性原则的乐之间虽然存在着巨大的张力,但两者的... 详细信息

荀子在继承了儒家传统礼乐思想的基础上,对其进行了历史性地改造,第一次比较深入全面地探讨了礼乐思想的不同内涵与作用,提出并论述了"乐合同,礼别异"的观点。他认为,强制性原则的礼与调和性原则的乐之间虽然存在着巨大的张力,但两者的矛盾并非不可调和。礼乐同构、"情通礼乐","情"是沟通礼与乐的桥梁,二者通过"情"从其根源上实现了内在张力的平衡。儒家传统的礼乐思想,在荀子的手中实现了情感论的转向。荀子将礼与乐放在同一个视域中进行考察,为制度理性与审美价值的和谐一致找到了合法性依据,对中国传统的诗学与美学理论也具有极大的启迪意义。

关键词：荀子礼乐张力情感转向

Manufacture the conducting polymer with light

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2025年第1期68卷 8-9页

作者： yang Li Tianyu Li yan Ji Baoguang liu College of Electronic and Optical Engineering & College of Flexible Electronics (future Technology) Nanjing University of Posts & Telecommunications

Poly(3,4-ethylenedioxythiophene) (PEDOT), heralded as the “king” of conducting polymers, is esteemed in bioelectronics for its mixed electronic and ionic conductivity, mechanical properties compatible with biological tissues, tunable healing ability and stability in diverse environments [1]. Based on additive manufacturing of three-dimensional structures,PEDOT realizes the implementation in the efficient production of flexible bioelectronics, the construction of intricate electrode-neural implantations, and the development of smart brain-computer-interfaces [2].

关键词：

Synthetic control of chiral pore surfaces in covalent organic frameworks for enantioselective separation of chiral drugs

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2025年

作者： Shiguo fu Xiaofeng Zhang Kaixuan Wang Linfeng Chen Fan Xia Yong Cui yan liu School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules and State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Faculty of Materials Science and Chemistry China University of Geosciences

Enantioselective separations of racemates using porous materials are highly attractive and significant in both fundamental research and technological applications. However, achieving controlled chiral pore surfaces to create the necessary driving force for enantiomer discrimination poses a fundamental challenge. Herein, we demonstrate that chiral covalent organic frameworks(COFs) possess the essential characteristics for effective enantioseparations through synthetic control over pore surfaces. We synthesized three 3D chiral COFs (CCOFs) featuring abundant chiral recognition sites on the pore walls via the condensation of enantiopure dialdehyde of 2,2′-dihydroxy-1,1′-binaphthyl and tetraamine. All CCOFs with high stability exhibit an 11-fold interpenetrated framework with tubular open channels, decorated with dihydroxyl or diethoxyl groups. The CCOFs with dihydroxyl groups serve as solid adsorbents for the adsorptive separation and solid-phase extraction of various chiral 1-phenylethanol-derived enantiomers, particularly racemic drugs, achieving up to 98%enantiomeric excess. In contrast, the CCOF with diethoxy groups is unable to resolve the racemates. These CCOF materials can be recycled and reused without any apparent loss of performance. Density functional theory (DFT) calculations reveal that the enantiospecific recognition arises from the well-organized chiral inner sphere and multiple chiral host-guest interactions.

关键词：