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| 1 | Efficient oxygen reduction reaction by a highly porous,nitrogen-doped carbon sphere electrocatalyst through space confinement effect in nanopores显示文摘A highly porous nitrogen-doped carbon sphere(NPC)electrocatalyst was prepared through the carbonization of biomass carbon spheres mixed with urea and zinc chloride in N_(2) atmosphere.The sample carbonized at.1000℃ demonstrates a superior oxygen reduction reaction(ORR)performance over the Pt/C electrocatalyst,while its contents of pyridinic nitrogen and graphitic nitrogen are the lowest among samples synthesized at the same or lower carbonization temperatures.This unusual result is explained by a space confinement effect from the microporous and mesoporous structures in the microflakes,which induces the further reduction of peroxide ions or other oxygen species produced in the first step reduction to water to have the preferred overall four electron reduction ORR process.This work demonstrates that in addition to the amount or species of its aptive sites,the space confinement can be a new approach to enhance the ORR performance of precious-metal-free,nitrogen-doped carbon electrocatalysts. | Zheyang MO Weiyi YANG Shuang GAO Jian Ku SHANG Yajun DING Wuzhu SUN Qi LI | 2021 | Journal of Advanced Ceramics2021，10，4： | 3 |
| 2 | Influence of silicon cluster on epitaxial growth of silicon carbide显示文摘Precursor concentration dependences of growth rate, doping concentration and surface morphology have been investigated in the epitaxial growth of 4H-SiC(0001) epilayers with horizontal hot-wall CVD system using various precursor concentrations under constant C/Si ratio. Form the experimental data it is found that silicon cluster which is formed through gas phase nucleation plays an important role in controlling the doping concentration and epitaxial growth rate of the silicon carbide. It was observed that the concentration of silicon clusters cannot reach the equilibrium value in the process by using a low SiH 4 concentration, and this phenomenon has not been reported by others. | LI ZheYang LI Yun CHEN Chen HAN Pin | 2011 | Science China(Physics,Mechanics & Astronomy)2011，54，9： | 1 |
| 3 | On the operating speed and energy efficiency of GaN-based monolithic complementary logic circuits for integrated power conversion systems显示文摘Gallium nitride(GaN)-based power conversion systems exhibit striking competitiveness in realizing compact and high-efficiency power management modules.Recently emerging GaN-based p-channel field-effect transistors(FETs)and monolithic integration techniques enable the implementation of GaN-based complementary logic(CL)circuits and thereby offer an additional pathway to improving the system-level energy efficiency and functional-ity.In this article,holistic analyses are conducted to evaluate the potential benefits of introducing GaN CL circuits into the integrated power systems,based on the material limit of GaN and state-of-the-art experimental results.It is revealed that the propagation delay of a single-stage CL gate based on the commercial p-GaN gate power HEMT(high-electron-mobility transistor)platform could be as short as sub-nanosecond,which sufficiently satis-fies the requirement of power conversion systems typically with operating frequencies less than 10 MHz.With the currently adopted n-FET-based logic gates(e.g.,directly coupled FET logic)replaced by CL gates,the power consumption of peripheral logic circuits could be substantially suppressed by more than 10^(3) times,mainly due to the elimination of the pronounced static power loss.Consequently,the energy efficiency of the entire system could be substantially improved. | Zheyang Zheng Han Xu Li Zhang Kevin J.Chen | 2021 | Fundamental Research2021，1，6： | 1 |
| 4 | Epitaxial growth of 4H-SiC on 4* off-axis substrate for power device 显示文摘 | Li Zheyang Han Ping Li Yun | 2011 | Chin Phys Lett2011，28，9： | 1 |
| 5 | Ti/4H-SiC Schottky barrier diodes with field plate and B^+implantation edge termination technology显示文摘 | Chen Gang Li Zheyang Bai Song | 2007 | Chinese journal of Semiconductors2007，28，9： | 1 |
| 6 | Isotope Geochemistry of the Xinchang -Yongjia Silver (Lead-Zinc)Ore Belt in Eastern Zhejiang Province显示文摘In the Xinchang-Yongjia silver (lead-zinc) ore belt, there mainly occur the large to medium-sized Haoshi, Bamao, Dalingkou and Wubu silver deposits or silver-bearing lead-zinc deposits. On the basis of researches on these typical deposits, the mechanism of leaching-drawing mineralization of Mesozoic geothermal water and the related model are put forward in this paper in the light of the time interval between rock and formation ages as well as hydrogen, oxygen, sulphur and lead isotope geochemical characteristics. The major metallogenic process occurred in volcanic rock layers. The ore-forming fluids are geothermal water coming from meteoric water and circulating at shallow layers. This geothermal water leached and absorbed ore-forming materials from its country rocks during its flowing (such metallogenic elements as silver, lead-zinc and sulphur mainly came from consolidated volcanic rocks), leading to the formation of meso - epithermal silver deposits. | Xu Butai, Li Changjiang Zhejiang Institute of Geology and Mineral Resources, Hangzhou, Zhejiangand Chen Haoshou Department of Earth Sciences, Zhejiang U niversity, Hangzhou, Zheyang Liu Xinzhu | 1995 | Acta Geologica Sinica(English Edition)1995，69，1： | 0 |
| 7 | Effects of dimethyl ether on soot formation in premixed laminar flame by laser induced incandescence method显示文摘The control of PM emission is a rather complicated problem to be solved both for diesel engine and GDI engines.There are vast factors affecting PM emission,the fuel,A/F,combustion temperature and so on.But undoubtedly,most efforts are paid to exhaust aftertreatment,rather than the control of generation.This paper is to investigate the effect of dimethyl ether(DME,CH3OCH3)on soot generation in flame.Therefore,a laser induced incandescence(LII)measurement system for soot volume concentration measurements in flame is used.Two DME gaseous mixtures were prepared with equivalence ratios 1 and 2.To highlight its effect on soot formation,acetylene known as the precursor of soot,is added in different ratios.Similarly,CO2 is mixed to simulate exhaust gas recycling(EGR)effect in engines.The experimental results indicate that the fuel property and A/F ratio are the dominating factors for the generation of soot during combustion.The combustion of DME doesn't emit soot obviously even under rich mixture condition.When burning the mixture of DME and acetylene(C2H2)in different proportion,there is barely soot emission at equivalence ratio of 1.The soot emission increases as the proportion of C2H2 increases at equivalence ratio 2,and the DME addition reduces the soot emission of C2H2 flame.CO2 dilution doesn't lead to the increase of soot when burning DME at equivalence 1 and 2.Soot emission is lower when the mixture of DME and acetylene is diluted by CO2,though soot volume concentration increases slightly as the proportion of C2H2 increases.The kinetic analysis indicates that the combustion of DME does not produce the precursor of soot.Under fuel-rich combustion conditions,C2H2 reacts with H radical to form C2H3,which leads to soot.When DME is added,it competes for H radical,which reduces the formation of C2H3 and thus reduces soot formation.The research carried out in this paper indicates that DME fuel has obviously power to reduce soot formation during combustion,no matter whether it is diluted by CO2 or mixed with soot precursor substance C2 H2. | Zengqiang Zhu Zheyang Li Chao Liu Xiao Chen Shenghua Liu | 2020 | Journal of Traffic and Transportation Engineering(English Edition)2020，7，3： | 0 |
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