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Search Results: 1 - 10 of 86876 matches for " CHEN Heng-quan "
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Fe-N-C 类催化剂在碱性燃料电池中的研究进展
Recent Progress for Fe-N-C Electrocatalysts in Alkaline Fuel Cells

邓 昕,陈亨权,胡 野,和庆钢
DENG Xin
, CHEN Heng-quan, HU Ye,HE Qing-gang

- , 2018, DOI: 10.13208/j.electrochem.171213
Abstract: 摘要 随着阴离子交换膜的出现、发展和应用,碱性燃料电池的优势日趋明显,针对碱性燃料电池的研究也更广泛而深刻. 在碱性燃料电池中,除了其固有的对催化剂的高包容性和动力学优越性,阴离子交换膜让阴离子定向迁移,从而实现了很好的水相管理,降低了电池中“水涝”的几率,也提供了更广阔的燃料选择空间. 氧还原反应是碱性燃料电池中的重要部分,且其反应动力学相较于氢氧化反应缓慢. 因此,选择并研制合适的阴极氧还原反应催化剂,是提高碱性燃料电池性能和促进燃料电池规模化使用的关键. Fe-N-C类催化剂因其在碱性条件下接近甚至优于 Pt 基催化剂的性能,被视为最有潜力替代 Pt 的非贵金属催化剂. 本文从近 5 年来 Fe-N-C 类催化剂的合成方法、催化活性位点和氧还原反应机理以及在燃料电池中的应用三方面进行了综述.
Fuel cells are highly recommended nowadays due to their intrinsic advantages such as high energy conversion efficiency, nearly no pollution, and convenient operation. With the development of anion exchange membrane, alkaline fuel cells have gone through a renaissance thanks to their superiorities such as faster reaction kinetics, wider choices for both fuels and electrocatalysts. It is essential to find an appropriate electrocatalyst for oxygen reduction reaction (ORR) to improve the performance of alkaline fuel cells. Further commercialization of the widely used Pt-based materials has suffered from disadvantages such as scarcity and high cost. As alternatives to largely investigated Pt-based materials, Fe-N-C electrocatalysts have gained increasing attention. However, Fe-N-C electrocatalysts still face problems including imperfect stability and durability, low metal loading, unclear catalytic mechanism and active sites, which has further hindered their design and synthesis. In this review, Fe-N-C electrocatalysts for alkaline fuel cells are discussed from the following three aspects, namely, the synthesis methods, the active sites and mechanisms, and their applications in recent five years. To optimize synthetic conditions, two kinds of typical synthetic methods are overviewed and some synthetic examples in the recent five years are summarized. Three active sites such as FeN4/C, Fe-N2+2/C, and Fe-N2/C, as well as those active sites concerned more widely in recent research for Fe-N-C electrocatalysts are also reviewed, which lays a good foundation for future design of Fe-N-C electrocatalysts. Furthermore, the single cell performance data are provided for the first time in order to enhance the application of the Fe-N-C electrocatalysts in alkaline fuel cells. As a whole, this review aims at providing theoretical support and guidance for future design and synthesis of commercial Fe-N-C electrocatalysts
AN ANALYSIS ON INEFFICACY OF ELECTROLYTE FOR ELECTROCHEMICAL POLISHING
电化学抛光中电解液的失效分析

LIU Heng-quan,JI Shi-wei,PAN Chang-jiang,HUANG Nan,
刘恒全
,季士委,潘长江,黄楠

腐蚀科学与防护技术 , 2007,
Abstract: The functions of phosphorus acid,sulfur acid and cheese anhydride in electrolyte for electrochemical polishing were stated in this paper.Using stainless steel as research object,the inefficacy of electrolyte solution was analyzed by investigating the changes of concentration of Fe3+ and Cr3+ as a function of current density.The influence of each ingredient in the elecrolyte on polishing effeciency was analyzed,moreover,the index of judging the inefficacy of the electrolyte and the relevant measuring method were obtained,the control range of three ingredients was also detemined.It is important to control technical process so that to guarantee the quality of electrochemical polishing.
Preparation and Application of the Hydrophilic Amino-Silicone Softener by Emulsion Polymerization  [PDF]
Ruza Artikboeva, Yue Wu, Mingxing Yang, Chen Jie, Quan Heng
Advances in Chemical Engineering and Science (ACES) , 2020, DOI: 10.4236/aces.2020.101001
Abstract: The amino poly-siloxane was modified with self-made polyether silicones by the crafts of emulsion polymerization. We studied the emulsifier, the dosage of emulsifier initiator, polyether/silane coupling agent, pH value. There are some results of the research indicated in the following. First, there are many factors for the hydrophilic amino-silicone softener both on the polymerization process and the performance, such as the proportion and amount of emulsifier, initiator dosage, the mass ratio of the polyether and hydrogen silicone oil, the choice of silicone coupling agent, and the ratio and dosage of polyether silicones silane coupling agent. Second, the amount of hydrogen of the hydrogen silicones and the choice of catalyst are the key points on the synthesis of polyether silicones. The amount of hydrogen should be low and the catalyst must be economical and efficient and its introduction should be small and times, other more the holding time is not too long. The next one is that, in the process of hydrolysis of silane coupling agent, we need some acid to adjust pH value, or they will be broken down. The most important one but not the last is that the epoxy group can improve the products low-temperature supple and the persistence of the finishing fabric, furthermore it can reduce yellowing and has a good stability of the inorganic salt, however, it will be destroyed if the reaction temperature for epoxy is too high. What’s more, it is very economical and environmental that the process of emulsion is simple and with less emulsifier.
Eco-friendly Synthesis of Cyclododecanone from Cyclododecatriene  [PDF]
Qi Feng, De-Kai Yuan, Dao-Quan Wang, Xiao-Mei Liang, Jian-Jun Zhang, Jin-Ping Wu, Fu-Heng Chen
Green and Sustainable Chemistry (GSC) , 2011, DOI: 10.4236/gsc.2011.13011
Abstract: An eco-friendly synthesis of cyclododecanone (CDON) from cyclododecatriene (CDT) is described. Selec- tive epoxidation of CDT with hydrogen peroxide using hexadecyl trimethyl ammonium heteropolyphospha- totungstate [(n-C16H33NMe3)3PW4O16, HAHPT] as catalyst and water as solvent followed by the hydrogena- tion on Raney nickel catalyst gave cyclododecanol (CDOL). The latter was oxidized with hydrogen peroxide using HAHPT as catalyst and a mixture of water and t-butanol as solvent to afford CDON. The total yield was 53.4% under the optimum reaction conditions.
Bioleaching of Low-grade Ni-Cu Sulfide Ore
硫杆菌浸出低品位镍铜硫化矿

CHEN Quan-jun,FANG Zhao-heng,
陈泉军,方兆珩

过程工程学报 , 2001,
Abstract: Bioleaching of low-grade Ni-Cu sulfide ore from Jin-chuan with thiobacillus ferrooxidans (TF5) and thiobacillus thiooxidans (TT) is investigated. The effect of pH, inoculation, pulp density on leaching is presented. The leaching process inoculated with different blend of TF5 and TT is also examined. These experiments confirm that the leaching pH should be controlled at about 2.0, the best inoculation quantity 3.0(109 cells/ml, low pulp density is more favorable for leaching, and the extraction of nickel is increased by inoculation with the blend of TF5 and TT.
Boileaching of Ni, Cu and Co from a Low-grade NiCu Sulfide Ore
生物浸出低品位镍铜硫化矿中的镍、铜、钴

CHEN Quan-jun,FANG Zhao-heng,
陈泉军
,方兆珩

过程工程学报 , 2001,
Abstract: Bioleaching of Ni, Cu and Co from the Jinchuan low-grade NiCuCo sulfide ore has been investigated with aerated leaching, agitated leaching with air bubbling, and column leaching respectively. The highest recovery was achieved in the aerated leaching. Leaching 20 d with pulp density of 15%, the leached Ni, Cu and Co were 95.4%, 48.6% and 82.6% respectively. By agitated leaching with air bubbling for 14 d at the pulp density of 25%, the leached Ni, Cu and Co were 80.2%, 45.2% and 78.4% respectively. With column leaching for 49 d, the leached Ni, Cu and Co were 48.5%, 37.5% and 33.6% respectively.
Abelian and Non-Abelian Quantum Geometric Tensor
Yu-Quan Ma,Shu Chen,Heng Fan,Wu-Ming Liu
Physics , 2010, DOI: 10.1103/PhysRevB.81.245129
Abstract: We propose a generalized quantum geometric tenor to understand topological quantum phase transitions, which can be defined on the parameter space with the adiabatic evolution of a quantum many-body system. The generalized quantum geometric tenor contains two different local measurements, the non-Abelian Riemannian metric and the non-Abelian Berry curvature, which are recognized as two natural geometric characterizations for the change of the ground-state properties when the parameter of the Hamiltonian varies. Our results show the symmetry-breaking and topological quantum phase transitions can be understood as the singular behavior of the local and topological properties of the quantum geometric tenor in the thermodynamic limit.
The Euler Number of Bloch States Manifold and the Quantum Phases in Gapped Fermionic Systems
Yu-Quan Ma,Shi-Jian Gu,Shu Chen,Heng Fan,Wu-Ming Liu
Physics , 2012, DOI: 10.1209/0295-5075/103/10008
Abstract: We propose a topological Euler number to characterize nontrivial topological phases of gapped fermionic systems, which originates from the Gauss-Bonnet theorem on the Riemannian structure of Bloch states established by the real part of the quantum geometric tensor in momentum space. Meanwhile, the imaginary part of the geometric tensor corresponds to the Berry curvature which leads to the Chern number characterization. We discuss the topological numbers induced by the geometric tensor analytically in a general two-band model. As an example, we show that the zero-temperature phase diagram of a transverse field XY spin chain can be distinguished by the Euler characteristic number of the Bloch states manifold in a (1+1)-dimensional Bloch momentum space.
PHOTOLUMINESCENCE BEHAVIOR OF QUANTUM DOTS IN SPHERICAL GLASS MICROCAVITY
玻璃球形微腔中量子点发光行为研究

JIA Rui,JIANG De,Sheng,CHEN Jing,Hao,TAN Ping,Heng,SUN Bao,Quan,
贾锐
,张敬波

红外与毫米波学报 , 2001,
Abstract: Micrometer sized spherical glass microspheres were fabricated. CdSeS semiconductor nanometer clusters were incorporated into spherical microcavities. When a single microsphere was excited by a laser beam, the whispering gallery mode resonance of the photoluminescence of CdSeS quantum dots in the spherical microcavities was realized by the multiple total internal reflections at the spherical interface. The coupling of restricted electronic and photonic states was realized.
High efficiency continuous-wave tunable signal output of an intracavity singly resonant optical parametric oscillator based on periodically poled lithium niobate

Ding Xin,Sheng Quan,Chen N,Yu Xuan-Yi,Wang Rui,Zhang Heng,Wen Wu-Qi,Wang Peng,Yao Jian-Quan,

中国物理 B , 2009,
Abstract:
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