检索结果-南通市图书馆

Effects of CeO_(2)pre-calcined at different temperatures on the performance of Pt/CeO_(2)-C electrocatalyst for methanol oxidation reaction

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2021年第7期28卷 1224-1232页

作者： guo-qing Li Pu-kang Wen Chen-qiang Gao Tian-yi Zhang Jun-yang Hu yu-hao Zhang Shi-you Guan qing-feng Li bing Li School of Mechanical and Power Engineering East China University of Science and TechnologyShanghai 200237China School of Materials Science and Engineering East China University of Science and TechnologyShanghai 200237China Institute for Sustainable Energy College of SciencesShanghai UniversityShanghai 200237China Department of Energy Conversion and Storage Technical University of DenmarkLyngby 2800Denmark

Pt/CeO_(2)-C catalysts with CeO_(2)pre-calcined at 300-600 ℃were synthesized by combining hydrothermal calcination and wet *** effects of the pre-calcined CeO_(2)on the performance of Pt/CeO_(2)-C catalysts in methanol oxidation were *** Pt/CeO_(2)-C catalysts with pre-calcined CeO_(2)at 300-600 ℃showed an average particle size of 2.6-2.9 nm and exhibited better methanol elec-tro-oxidation catalytic activity than the commercial Pt/C *** specific,the Pt/CeO_(2)-C catalysts with pre-calcined CeO_(2)at 400 ℃dis-played the highest electrochemical surface area value of 68.14 m2·g−1 and If/Ib ratio(the ratio of the forward scanning peak current density(If)and the backward scanning peak current density(Ib))of 1.26,which are considerably larger than those(53.23 m2·g−1 and 0.79,respectively)of the commercial Pt/C catalyst,implying greatly enhanced CO tolerance.

关键词： direct methanol fuel cell platinum/cerium dioxide-carbon electrocatalyst methanol oxidation

Stochastic Resonance in an Asymmetric Mono-stable System Subject to Two Periodic Forces and Multiplicative and Additive Noise

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2009年第2期51卷 283-286页

作者： LUO Xiang-dong guo feng ZHOU yu-Rong School of Information Engineering Southwest University of Science and Technology Mianyang 621010 China School of Life Science and Technology University of Electronic Science and Technology Chengdu 610054 China

The phenomenon of stochastic resonance （SR） in an asymmetric mono-stable system subject to two external periodic forces and multiplicative and additive noise is investigated. It is shown that the signal-to-noise ratio （SNR） for the fundamental and higher harmonics is a non-monotonic function of the intensities of the multiplicative and additive noise, as well as of the system parameter. Moreover, the SNR for the fundamental harmonic decreases with the increase of the system asymmetry, while the SNR for the higher harmonics behaves non-monotonically as the system asymmetry varies.

关键词： stochastic resonance asymmetric mono-stable system signal-to-noise ratio

Theoretical Study on Resonance Raman Spectra of Tetraoxaporphyrin Dication by TDDFT Calculation

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2015年第5期28卷 -页

作者： guo-bing Wang Hui-qing Zhao Zhen-lin Zhang Wen-lou Wang dong-ming Chen Department of Chemical Physics University of Science and Technology of China Hefei 230026China Department of Chemistry College of Basic Medicine Anhui Medical University Hefei 230032 China

The B state excited resonance Raman scattering of tetraoxaporphyrin dication (TOP2+) was theoretically studied with DFT/TDDFT calculations and the sum-over-states approach of polarizability including both the A and B terms contributions. The resonance Raman spectra calculated with PBE1PBE, B3LYP, Cam-B3LYP, and B3LYP-D3 functionals are similar to each other in general, with PBE1PBE and B3LYP being better in reproducing resonance Raman intensities in comparison with the experiment. The calculated relative intensities of the totally symmetric modes are excellently consistent with the experiment. The TDDFT calculations manifested a considerable deformation of the B state along the ν2, ν6, ν7, and ν8 modes, which is responsible for the strong resonance Raman intensities of these modes. The resonance Raman intensities of non-totally symmetric modes were calculated to be weaker than the totally symmetric modes by one or two order of magnitude, which qualitatively agrees with the experiment. However, the resonance Raman intensity of the ν10 mode (CβCβ stretch, B1g symmetry) predicted by TDDFT calculations is unexpectedly small whereas that of the ν11 mode (symmetric CαCm stretch, B1g symmetry) is too large, which is assumed to be caused by the Jahn-Teller instability for the B state of TOP2+.

关键词： Tetraoxaporphyrin Resonance Raman TDDFT Excited state structure Franck-Condon mechanism

Production of low-silicon molten iron from high-silica hematite using biochar

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

Journal of Iron and Steel Research International 2017年第1期24卷 27-33页

作者： Hui-qing Tang Xiu-feng Fu Yan-qi Qin Shi-yu Zhao qing-guo Xue State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

A new method of utilizing high-silica hematite to produce low-silicon molten iron was *** this method,FASTMELT,which comprised direct reduction and melt separation processes,was applied,with highly reactive biochar as the reductant in the direct reduction *** proposed method was experimentally investigated and the results show that the method is *** the direct reduction stage,ore-char briquette could achieve a metallization rate of 84%-88% and residual carbon of 0.27-0.89mass% at temperature of 1373 K,biochar mixing ratio of 0.8-0.9,and reduction time of 15 *** silica particles remained embedded in the iron phase after the *** the melting separation stage,molten iron with a carbon content of 0.02-0.03mass% and silicon content of 0.02-0.18mass%could be obtained from the metallic briquettes under the above-mentioned conditions;the iron recovery rate was83%-91% and impurities in the obtained metal were negligible.

关键词： High-silica hematite Low-silicon molten iron Biochar Direct reduction Melt separation

Grate-kiln pelletization of Indian hematite fines and its industrial practice

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2017年第5期24卷 473-485页

作者： De-qing Zhu feng Zhang Zheng-qi guo Jian Pan Wei yu School of Minerals Processing and Bioengineering Central South University Institution of Resources Strategy Wuhan Iron and Steel Corporation

Indian hematite fines normally have a high iron grade and minor impurities; they are usually used as sinter fines for feeding into a blast furnace. In this work, the grindability properties of two kinds of Indian hematite fines and the roasting behaviors and induration characteristics of pellets made from these fines were revealed through experiments involving dry ball milling and small-scale and pilot-scale tests. In addition, the microstructures of the particles of ground India hematite fines and fired pellets were investigated using optical microscopy. On the basis of the results, a grate-kiln production line with an annual output of 1.2 Mt of oxidized pellets was established in India. This pellet plant operates stably and reliably, further confirming that preparing high-quality pellets with Indian hematite fines pretreated by dry ball milling is an industrially feasible process. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.

关键词： Ball milling Blast furnaces Industrial management Kilns Milling (machining) Pelletizing

Multi-physical fields distribution in billet during helical electromagnetic stirring:A numerical simulation research

在线全文

学校读者我要写书评

暂无评论

China Foundry 2024年第1期21卷 51-59页

作者： dong Pan qing-tao guo Kai-lun Zhang Fu-zhi yu yu-ying Li yu-bao Xiao State Key Laboratory of Metal Materials for Marine Equipment and Application Anshan 114009LiaoningChina Ansteel Beijing Research Institute Co. Ltd.Beijing 102200China

Electromagnetic stirring is one of the widely applied techniques to modify the quality of casting *** from conventional rotate stirring,the helical stirring is more professional in assisting multi-dimensional flow of molten metal and eliminating solidification *** this study,the single-winding helical stirring(SWHS)was introduced,offering advantages such as smaller volume and lower electromagnetic shielding compared to traditional helical stirring *** a comprehensive numerical simulation,the stirring parameters of SWHS were adjusted to yoke inclination angle of 43°and frequency of 12 *** higher electromagnetic force and flow velocity in drawing direction,as well as the lower temperature gradient induced by the SWHS,are positive factors for homogeneous solidification of *** experimental results on Al-8%Si alloy and 0.4%C-1.1%Mn steel demonstrate that compared to rotate stirring,the SWHS process can induce better billet quality and is more effective in accelerating the equiaxed expansion and reducing element *** SWHS process can enhance the equiaxed ratio of the billet by 58.3%and reduce segregation degree of carbon element by 10.97%.Consequently,SWHS holds great promise as a potential approach for improving the quality of continuous casting billets.

关键词： billet electromagnetic stirring helical solidification element segregation numerical simulation

Reaction characteristic of PTFE/Al/Cu/Pb composites and application in shaped charge liner

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2022年第9期18卷 1578-1588页

作者： Huan-guo guo yuan-feng Zheng Suo He qing-Bo yu Chao Ge Hai-fu Wang Beijing Institute of Technology Institution China

In this paper, the reaction characteristic and its application in shaped charge warhead of a novel reactive material, which introduced copper(Cu) and plumbum(Pb) into traditional polytetrafluoroethylene/aluminum(PTFE/Al), are studied. The thermal analysis and chemical reaction behavior of the PTFE/Al/Cu/Pb mixture are investigated by Differential Scanning Calorimetry(DSC),Thermo-gravimetry(TG), and Xray Diffraction(XRD) techniques. Then, the shaped charge liners with PTFE/Al/Cu/Pb reactive materials are fabricated, and the X-ray experiments show that they could form reactive jets with excellent performance under the detonation effects of the shaped charge. Based on that, the penetration experiments of shaped charge with PTFE/Al/Cu/Pb reactive liner against steel plates are carried out, and the results demonstrate that the PTFE/Al/Cu/Pb reactive jets could produce a deeper penetration depth compared to the traditional PTFE/Al reactive jets. Meanwhile, the PTFE/Al/Cu/Pb reactive jets also show significant inner-blast effects, leading to dramatically cracking or fragmentation behavior of the penetrated steel plates. This new PTFE/Al/Cu/Pb reactive liner shaped charge presents enhanced penetration behavior for steel targets that incorporates the penetration capability of a high-density and ductility jet, and the chemical energy release of PTFE-matrix reactive materials.

关键词： Reactive materials Shaped charge Reactive liner Jet formation Penetration behavior

Large-Capacity and High-Speed Instruction Cache Based on Divide-by-2 Memory Banks

在线全文

学校读者我要写书评

暂无评论

Journal of Electronic Science and Technology 2021年第4期19卷 335-349页

作者： qing-qing Li Zhi-guo yu Yi Sun Jing-He Wei Xiao-feng Gu with the Engineering Research Center of IoT Technology Applications(Ministry of Education) Jiangnan UniversityWuxi 214122 with the No.58 Research Institute China Electronics Technology Group CorporationWuxi 214035

An increase in the cache capacity is usually accompanied by a decrease in access *** balance the capacity and performance of caches,this paper proposes an instruction cache(ICache)architecture based on divide-by-2 memory banks(D2MB-ICache).The control circuit and memory banks of D2MB-ICache work at the central processing unit(CPU)frequency and the divide-by-2 CPU frequency,respectively,so that the capacity of D2MB-ICache can be expanded without lowering its *** sequential access,D2MB-ICache can output the required instruction from memory banks per CPU cycle by dividing the memory banks with a partition mechanism and employing an inversed clock *** non-sequential access,D2MB-ICache will fetch certain jump instructions one or two more times,so that it can catch the jump of the request address in time and send the correct instruction to the *** results show that,compared with conventional ICache,D2MB-ICaches with the same and double capacities show a maximum frequency increase by an average of 14.6%and 6.8%,and a performance improvement by an average of 10.3%and 3.8%,***,energy efficiency of 64-kB D2MB-ICache is improved by 24.3%.

关键词： Cache capacity expansion divide-by-2 frequency instruction cache(ICache) inversed clock.

End-to-side neurorrhaphy repairs peripheral nerve injury：sensory nerve induces motor nerve regeneration

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2017年第10期12卷 1703-1707页

作者： qing yu She-hong Zhang Tao Wang feng Peng dong Han yu-dong Gu Department of Hand Surgery Huashan Hospital of Fudan UniversityKey Laboratory of Hand Reconstructionthe Ministry of HealthKey Laboratory of Peripheral Nerve and MicrosurgeryShanghaiChina Department of Rehabilitation Medicine Huashan Hospital of Fudan UniversityShanghaiChina

End-to-side neurorrhaphy is an option in the treatment of the long segment defects of a *** involves suturing the distal stump of the disconnected nerve（recipient nerve） to the side of the intimate adjacent nerve（donor nerve）.However,the motor-sensory specificity after end-to-side neurorrhaphy remains *** study sought to evaluate whether cutaneous sensory nerve regeneration induces motor nerves after end-to-side *** rats were randomized into three groups：（1） end-to-side neurorrhaphy using the ulnar nerve（mixed sensory and motor） as the donor nerve and the cutaneous antebrachii medialis nerve as the recipient nerve;（2） the sham group：ulnar nerve and cutaneous antebrachii medialis nerve were just exposed;and（3） the transected nerve group：cutaneous antebrachii medialis nerve was transected and the stumps were turned over and *** 5 months,acetylcholinesterase staining results showed that 34% ± 16% of the myelinated axons were stained in the end-to-side group,and none of the myelinated axons were stained in either the sham or transected nerve *** fluorescent tracing of spinal motor neurons and dorsal root ganglion showed the proportion of motor neurons from the cutaneous antebrachii medialis nerve of the end-to-side group was 21% ± 5%.In contrast,no motor neurons from the cutaneous antebrachii medialis nerve of the sham group and transected nerve group were found in the spinal cord *** results confirmed that motor neuron regeneration occurred after cutaneous nerve end-to-side neurorrhaphy.

关键词： nerve regeneration peripheral nerve injury end-to-side neurorrhaphy motor-sensory specificity rat dorsal root ganglion motor neuron axon cutaneous antebrachii medialis nerve ulnar nerve acetylcholinesterase staining retrograde neuron tracing neural regeneration