检索结果-南通市图书馆

Epitaxial growth and air-stability of monolayer Cu2Te

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第1期29卷 99-102页

作者： K Qian L Gao h Li S Zhang J h yan C Liu J O Wang T Qian h Ding y y Zhang X Lin S X du h-J Gao Institute of Physics&University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100190China Institute of high Energy Physics Chinese Academy of SciencesBeijing 100049China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100190China

A new two-dimensional atomic crystal, monolayer cuprous telluride（Cu2Te） has been fabricated on a grapheneSi C（0001） substrate by molecular beam epitaxy（MBE）. The low-energy electron diffraction（LEED） characterization shows that the monolayer Cu2Te forms ■ superstructure with respect to the graphene substrate. The atomic structure of the monolayer Cu2Te is investigated through a combination of scanning tunneling microscopy（STM） experiments and density functional theory（DFT） calculations. The stoichiometry of the Cu2Te sample is verified by x-ray photoelectron spectroscopy（XPS） measurement. The angle-resolved photoemission spectroscopy（ARPES） data present the electronic band structure of the sample, which is in good agreement with the calculated results. Furthermore, air-exposure experiments reveal the chemical stability of the monolayer Cu2Te. The fabrication of this new 2D material with a particular structure may bring new physical properties for future applications.

关键词： cuprous telluride(Cu2Te) scanning tunneling microscopy(STM) density functional theory(DFT) chemical stability

MODIFICATION OF SURFACE MEChANICAL PROPERTIES OF POLyCARBONATE By B^+ AND O^+ IONS IMPLANTATION

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2002年第1期15卷 33-38页

作者： S.D. yao C. Sun S.Q. Zhou C.C. Sun y.h. Lu L. huang A. Vantomme Q. Zhao G. Langouche Sch. of Phys. Peking Univ. Beijing 100871 China

By implanting B+ and O+ ions respectively into polycarbonate (PC) plates, the surface mechanical properties of PC have been improved. Measurement by Nano Indenter II showed that the hardness of samples increased 7-25 times than that before implantation; and the modulus of elasticity raised 2-5 times. The wear-resistance was tested by ball crusher; the width and depth of the wear-streak decreased by 1/3-1/2 or even more. The structure, deformation and appearance were analyzed by using Micro-FTIR Spectra, ESCA method and the steps instrument. These analyses showed that the structure of PC had been modified: a series of new cross-linking yielded, it depends on the Linear Energy Transition (LET) of implanted ions in the high polymer compounds.

关键词： polycarbonate ion implantation surface modification

Impact Factors on Fracturing Results of Coal Seams and Appropriate Countermeasures

在线全文

学校读者我要写书评

暂无评论

Journal of Energy and Power Engineering 2010年第6期4卷 16-26页

作者： X. Wang y.h. Ding y. Xu y.y. duan Fracturing ＆ Acidizing Technical Service Center Research Institute of Petroleum Exploration and Development China NationalPetroleum Corp. Langfang 065007 China

hydraulic fracturing is one of the efficient means for the abundant low-permeability CBM （coal-bed methane） reserves in China, however, due to the unique features of coal seams （i.e., low temperature, strong adsorption and abnormal development of natural fracture systems） as compared with the conventional reservoirs, the fractures propagate is difficult and the risk of damage to coal seam itself and the hydraulic fractures would be extremely.h.gh in the course of fracturing. As a result, losses would be suffered on the post-frac production of CBM *** the mean of numerical simulation, in this paper, the main factors have impact on the post-frac results as well as the extent to which the impact is brought were researched, and the technical solutions for the improvement of the fracturing performance was put forwards.

关键词： Coal-seam fracturing hazard factors yield loss rate technical solutions.

POLAROGRAPhIC CATALyTIC WAVE OF GLyCyRRhIZIC ACID

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1995年第4期6卷 321-324页

作者： Song, JF Guo, W du, h NW Univ Xian Inst Electroanalyt Chem Xian 710069 Peoples R China

A polarographic catalytic wave of glycyrrhizic acid( I) in the presence of h2O2 is described. The electrochemical process is considered to be that I yielded a free radical intermediate through a one-electron reduction of its C = C double bond, and the active intermediate was oxidized to regenerate I. The catalytic wave should be new-type one due to reduction and regeneration of organic depolarizer.

关键词： POLAROGRAPhIC CATALyTIC WAVE OF GLyCyRRhIZIC ACID

A Study on the Testing Procedures of IEC 61850 Based Transformer Protective lED

在线全文

学校读者我要写书评

暂无评论

Journal of Energy and Power Engineering 2010年第11期4卷 58-62页

作者： N.h. Lee B.T. Jang y.h. Kim y.h. An J.y. han E.B. Shim Transmission ＆ Distribution Lab of KEPCO Research Institute 65 Munji-Ro Yuseong-Gu Daejeon Rebublic of Korea

Korea Electric Power Corporation in charge of the power IT project ＂Development of Prototype for Advanced Substation Automation System based on the Digital Control Technology＂, is performing the verification of performance of the substation automation system based on IEC 61850. In order to verify a transformer protective lED that might be operating in substation automation system, the new standardized document and procedures are required in the aspect of the utility like KEPCO. But there is nothing to describe systematically.h.w to verify IEC 6 1850 based lED in the system environment except an individual IED testing way. This paper will present the substation automation system based ways and procedures to verify the protective function of the IED using UML （Unified Modeling Language）.

关键词： IED conformance testing IEC61850 substation automation testing procedure.

Promotion Mechanism of h2O for Stereoselectivity in Pd(Ⅱ)-catalyzed C—h Aryiation of Diarylphosphinamides with Arylboronic Acids

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2020年第5期36卷 843-846页

作者： CAI yanchun JIAO Long QIU Xuepcng du Zhijun Polymer Composites Engineering laboratory Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022P.R.China

On the basis of a series of control experiments and nuclear magnetic resonance analyses,it is discovered that Boc-protected amino acid ligand coordinated to Pd center is partly replaced by N,N-dimethylformamide,and h2O can inhibit coordination of N,N-dimethylformamide to Pd *** novel action mechanism perfectly explains h2O promotion for stereoselectivity in Pd(II)-catalyzed C—h aryiation of diarylphosphinamides with arylboronic acids.

关键词： C-h activation Stereoselectivity Water Ligand exchange

Role of water on the h-abstraction from methanol by ClO

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2018年第9期30卷 89-98页

作者： Shanshan Tang Narcisse T.Tsona Junyao Li Lin du Environment Research Institute Shandong University Jinan 250100 China

The influence of a single water molecule on the reaction mechanism and kinetics of hydrogen abstraction from methanol （Ch3Oh） by the CIO radical has been investigated using ab initio calculations. The reaction proceeds through two channels： abstraction of the hydroxyl h-atom and methyl h-atom of Ch30h by CIO, leading to the formation of Ch30 ＋ hOC1 （＋h20） and Ch20h ＋ hOC1 （＋ h20）, respectively. In both cases, pre- and post-reactive complexes were located at the entrance and exit channel on the potential energy surfaces. Results indicate that the formation of Ch2Oh ＋ hOC1 （＋h20） is predominant over the formation of Ch30 ＋ hOC1 （＋h20）, with ambient rate constants of 3.07 x 10^-19 and 3.01 x 10^-23 cm^3/（***）, respectively, for the reaction without water. Over the temperature range 216.7-298.2 K, the presence of water is seen to effectively lower the rate constants for the most favorable pathways by 4-6 orders of magnitude in both cases. It is therefore concluded that water plays an inhibitive role on the Ch30h ＋ ClO reaction under tropospheric conditions.

关键词： Radical-molecule complex h-abstraction reaction Reaction rate constants Quantum chemical calculations

Vertical α-FeOOh nanowires grown on the carbon fiber paper as a free-standing electrode for sensitive h2O2 detection

在线全文

学校读者我要写书评

暂无评论

Nano Research 2016年第8期9卷 2260-2269页

作者： Shichao du Zhiyu Ren Jun Wu Wang Xi honggang Fu Institute of Theoretical chemistry Jilin University ChangChun 130023 China Key Laboratory of Functional Inorganic Material Chemistry Ministry of Education of the People's Republic of China School of Chemistry and Materials Science Heilongjiang University Harbin 150080 China

highly sensitive, selective, and stable hydrogen peroxide （h2O2） detection using nanozyme-based catalysts are desirable for practical applications. herein, vertical α-FeOOh nanowires were successfully grown on the surface of carbon fiber paper （CFP） via a low-temperature hydrothermal procedure. The formation of vertical α-FeOOh nanowires is ascribed to the structure-directing role of sodium dodecyl sulfate. The resulting free-standing electrode with one-dimensional （1D） nanowires offers oriented channels for fast charge transfer, excellent electrical contact between the electrocatalyst and the current collector, and good mechanical stability and reproducibility. Thus, it can serve as an efficient electrocatalyst for the reduction and sensitive detection of h2O2. The relation of the oxidation current of h202 with the concentration is linear from 0.05 to 0.5 mM with a sensitivity of -0.194 mA/（***2） and a low detection limit of 18μM. Furthermore, the portability in the geometric tailor and easy device fabrication allow extending the general applicability of this free-standing electrode to chemical and biological sensors.

关键词： α-FeOOh nanowires free-standing electrode synergistic effect electrocatalysis h2O2 detection

Catalytic synthesis of acetals and ketals with h3PW12O40/PAn

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2008年第1期27卷 89-94页

作者： yANG Shuijin ZhANG yijun du Xinxian Philippe G. Merle hubei Key Laboratory of Bioanalytical Technique Department of Chemistry and Environmental Engineering Hubei Normal University Huangshi 435002 China Department of Chemistry and Biochemistry Concordia University Montreal H4B 1R6 Canada

A new environmental friendly catalyst h3PW12O40/PAn was prepared and identified by means of FT-IR,XRD,and TG/*** optimum conditions have been found;that is,the mass ratio of PAn to h3PW12O40 is 1：1.5,the volume of methanol is 20 mL,and the reflux reaction time is 3 *** structural identity of Keggin units is preserved after the incorporation into polyaniline *** activities of h3PW12O40/PAn in synthesizing 2-methyl-2-ethoxycarbonylmethyl-1,3-dioxolane,2,4-dimethyl-2-ethoxycarbonylmethyl-1,3-dioxolane,cyclohexanone ethylene ketal,cyclohexanone 1,2-propanediol ketal,butanone ethylene ketal,butanone 1,2-propanediol ketal,2-phenyl-1,3-dioxolane,4-methyl-2-phenyl-1,3-dioxolane,2-propyl-1,3-dioxolane,and 4-methyl-2-propyl-1,3-dioxolane were *** has been demon-strated that h3PW12O40/PAn is an excellent *** factors concerned in these reactions were *** optimum conditions are as follows：the molar ratio of aldehyde/ketone to glycol（r） is 1：1.5,the mass ratio of the catalyst used to the reactants is 0.6%,and the reaction time is 1.0 *** these conditions,the yield is as follows：2-methyl-2-ethoxycarbonylmethyl-1,3-dioxolane,69.0%;2,4-dimethyl-2-ethoxycarbonylmethyl-1,3-dioxolane,79.5%;cyclohexanone ethylene ketal,78.9%;cyclohexanone 1,2-propanediol ketal,85.3%;butanone ethylene ketal,56.9%;butanone 1,2-propanediol ketal,78.1%;2-phenyl-1,3-dioxolane,76.3%;4-methyl-2-phenyl-1,3-dioxolane,94.2%;2-propyl-1,3-dioxolane,70.7%;and 4-methyl-2-propyl-1,3-dioxolane,79.2%.

关键词： phosphotungstic acid acetal ketal polyaniline catalysis