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Nanostructured Catalyst for Fischer-Tropsch Synthesis

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Chinese Journal of Chemistry 2018年第9期36卷 798-808页

作者： wa Gao Qingshan Zhu Ding ma College of Chemistry and Molecular Engineering and College of Engineering Peking University Beijing 100871 China Fritz-Haber-Institut der max-Planck-Gesellschaft Faradayweg 4-6 D-14195 Berlin Germany

Fischer-Tropsch synthesis （FTS） is a heterogeneous catalytic process for the production of fuels or chemicals from synthesis gas （CO ＋ H2）, which can be derived from nonpetroleum feedstocks such as natural gas, coal, or biomass. Co, Ru, Fe and Ni are all active in FTS, but only cheaper Fe and Co based catalysts are used in industry because the price of Ru is relatively high. However, the industrial Fe- and Co-based FTS catalysts normally work at a relatively high temperature range of 493--623 K in order to get a reasonable space time yield. Moreover, the product selectivity of FTS is governed by the law of polymerization, i.e., a so-called Anderson-Schulz-FIory distribution holds, which restricts its industrial application. In this account, we highlight some of our progress toward the design/fabrication of nanostructured Fe, Co and Ru catalysts to improve FTS activity at the low temperature and to change the product selectivity and confine the product distribution into a certain range.

关键词： catalyst Fischer-Tropsch synthesis nanostructure

Study on polarization properties of graphene coated D-shaped fiber

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Chinese Physics B 2018年第10期27卷 346-351页

作者： Xuejing Liu Luwen Yang Jingyun ma Caili Li wa Jin Weihong Bi School of Instrumentation Science and Opto-electronics Engineering Beihang UniversityBeijing 100191China School of Information Science and Engineering Key Laboratory for Special Fiber and Fiber Sensor of Hebei ProvinceYanshan UniversityQinhuangdao 066004China Key Laboratory for Special Fiber and Fiber Sensor of Hebei Province School of Information Science and EngineeringQinhuangdao 066004China

The optical properties of graphene coated D-shaped single mode fiber and photonic crystal fiber are numerically analyzed. Enhancement of the graphene-light interaction is found in graphene coated D-shaped photonic crystal fiber,which introduces a tunable polarization of the D-shaped fiber by changing the chemical potential of the coated *** optimal polarizer model is demonstrated with the extinction ratio of 66.26 dB/mm and the insertion loss of 9.4 dB/*** modulator extinction ratios of the TE mode and TM mode are 11.5 dB and 5 dB, respectively, with a device length of100 μm. This paper provides a theoretical reference for the optical property research of the graphene fiber.

关键词： photonic crystal fiber graphene polarization chemical potential

Effects of Shang Ke Jie Gu tablet on fracture healing in rabbits

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Discussion of Clinical Cases 2016年第3期3卷 6-8页

作者： Yanhua ma Fuyan Xie wa Gao Traditional Chinese and Western Medicine Branch of the Third Affiliated Hospital of Inner Mongolia Medical University BaotouChina

Objective:To study the effects of Shang Ke Jie Gu tablet on fracture healing in ***:40 New Zealand rabbits,half male and half female,were randomly divided into two groups:normal saline group(N group)and Shang Ke Jie Gu tablet group(S group).Each group consisted of 20 *** radial fracture models in upper and middle sections were made in rabbits and then intra-gastric administration was *** rabbits in each group were killed on the 10 th,20^(th),30^(th) and 40^(th) day after surgery,left radius was taken to get an *** degree of healing was assessed by the evaluation criteria of Shanghai Orthopaedics ***:The degree of fracture healing in S group was higher in the comparison with that in N ***:Shang Ke Jie Gu tablet might affect endochondral ossification during fracture healing of rabbits,and promote porosis and fracture healing.

关键词： Fracture healing Shang Ke Jie Gu tablet X-ray

Method of evaluating interface traps in Al2O3/AlGaN/GaN high electron mobility transistors

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Chinese Physics B 2019年第6期28卷 378-383页

作者： Si-Qin-Gao-wa Bao Xiao-Hua ma Wei-Wei Chen Ling Yang Bin Hou Qing Zhu Jie-Jie Zhu Yue Hao School of Advanced materials and Nanotechnology Xidian UniversityXi’an 710071China Key Laboratory of Wide Band-Gap Semiconductor materials and Devices School of MicroelectronicsXidian UniversityXi’an 710071China School of Science Inner Mongolia University of TechnologyHohhot 010051China 4China Academy of Space Technology(Xi’an)Xi’an 710071China

In this paper, the interface states of the AlGaN/GaN metal–insulator–semiconductor(MIS) high electron mobility transistors(HEMTs) with an Al2 O3 gate dielectric are systematically evaluated. By frequency-dependent capacitance and conductance measurements, trap density and time constant at Al2 O3/AlGaN and AlGaN/GaN interface are *** experimental results reveal that the density of trap states and the activation energy at the Al2 O3/AlGaN interface are much higher than at the AlGaN/GaN interface. The photo-assisted capacitance-voltage measurements are performed to characterize the deep-level traps located near mid-gap at the Al2 O3/AlGaN interface, which indicates that a density of deep-level traps is lower than the density of the shallow-level states.

关键词： AlGaN/GaN HEMTs interface traps frequency-dependent C–V measurements photo-assisted C–V measurements

Cellphone application rehabilitation management and evaluations of cardiopulmonary function and motor development in infants with congenital heart disease:a pilot study

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World Journal of Pediatrics 2023年第8期19卷 805-812页

作者： Ge-Jing-wa Zhao Zhi-Qiang Li Yang ma Yao-Bin Zhu Nan Ding Han-Lu Yi Shi-Jie Li Dao-Le Yan Jin-Rui Zhang Department of Cardiovascular Surgery II Beijing Children’s HospitalCapital Medical UniversityNational Center for Children’s Health56th Nan Lishi RdBeijing100045China Department of Healthcare Beijing Children’s HospitalCapital Medical UniversityNational Center for Children’s HealthBeijingChina

Congenital heart disease(CHD)has an estimated prevalence of 0.9%,with 0.3%requiring interventional or surgical intervention very early in ***,CHD surgery tends to be performed at a younger *** continued management of the condition is dependent on postoperative care and rehabilitation since the success rate of surgery has significantly increased[1,2].According to American Heart Association guidelines published in 2012.

关键词： surgery congenital younger

A novel Doppler frequency measurement method based on the closed-loop signal correlation for deep space exploration

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Research in Astronomy and Astrophysics 2021年第9期21卷 75-82页

作者： Tao Deng mao-Li ma Qing-Bao He Qing-Hui Liu Ya-Jun Wu Xin Zheng Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China University of Chinese Academy of Sciences Beijing 100049China Southern University of Science and Technology Shenzhen 518055China

In deep space exploration,it is necessary to improve the accuracy of frequency measurement to meet the requirements of precise orbit determination and various scientific studies.A phase detector is one of the key modules that restricts the tracking performance of phase-locked loop(PLL).Based on the phase relationship between adjacent signals in the time domain,a novel phase detector is presented to replace the arctangent phase *** new PLL,which is a closed loop signal correlation algorithm,shows good performance in tracking signals with high precision and the tracking accuracy of frequency of1 second integration is close to Cramer-Rao lower bound(CRLB)when setting proper *** data processing results further illustrate the excellent performance of the novel PLL.

关键词： Doppler measurement:Cramer-Rao lower bound carrier tracking:phase locked loop signal correlation

Mechanically Driven Alloying and Structural Evolution of Nanocrystalline Fe_(60)Cu_(40) Powder

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Journal of materials Science & Technology 1997年第4期13卷 354-358页

作者： Yuanda DONG and Xueming ma(School of materials Science and Engineering, Shanghai University, Shanghai 200072, China)Yuanzheng YANG(Dept. of Mechanical Engineering(2), South China University of Technology, Guangzhou 510641, China)Fangxin LIU and Genmiao wa School of materials Science and Engineering Shanghai University Shanghai 200072 China Dept. of Mechanical Engineering(2) South China University of Technology Guangzhou 510641 China Lab. of Structure Analysis University of Science and Technology of China Hefei 230026 China

Highly supersaturated nanocrystalline fcc Fe60Cu40 alloy has been prepared by mechanical alloying of elemental powders. The phase transformation is monitored by X-ray diffraction (XRD),Mossbauer spectroscopy and extended X-ray absorption fine structure (EXAFS). The powder obtained after milling is of single fcc structure with grain size of nanometer order. The Mossbauer spectra of the milled powder can be fitted by two subspectra whose hyperfine magnetic fields are 16 ma/m and 20 ma/m while that of pure Fe disappeared. EXAFS results show that the radial structure function (RSF) of Fe K-edge changed drastically and finally became similar to that of reference Cu K-edge, while that of Cu K-edge nearly keeps unchanged in the process of milling. These imply that bcc Fe really transforms to fcc structure and alloying between Fe and Cu occurs truly on an atomic scale. EXAFS results indicate that iron atoms tend to segregate at the boundaries and Cu atoms are rich in the fcc lattice. Annealing experiments show that the Fe atoms at the interfaces are easy to cluster to α-Fe at a lower temperature, whereas the iron atoms in the lattice will form γ-Fe first at temperature above 350℃, and then transform to bcc Fe

关键词： Mechanically Driven Alloying and Structural Evolution of Nanocrystalline Fe ma Cu Powder Figure

A critical review of preparation design and workability measurement of concrete material for largescale 3D printing

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Frontiers of Structural and Civil Engineering 2018年第3期12卷 382-400页

作者： Guowei ma Li waNG College of Architecture and Civil Engineering Beijing University of Technology Beijing 100124 China School of Civil Environmental and Mining Engineering The University of Western Australia Crawley WA 6009 Australia School of Mechanics and Civil engineering China University of Mining & Technology at Beijing Beijing 100083 China

In recent few years, significant improvement has been made in developing largescale 3D printers to accommodate the need of industrial-scale 3D printing. It is of great feasibility to construct structural components and buildings by means of 3D concrete printing. The major issues of this innovative technique focus on the preparation and optimization of concrete materials which possess favourable printable properties as well as the measurement and evaluation methods of their workability. This paper firstly introduces three largescale 3D printing systems that have been successfully applied in construction industry. It then summarizes the commonly used raw materials in concrete manufacturing. Critical factors that should be particularly controlled in material preparation are specified. Easy-extrusive, easy-flowing, well-buildable, proper setting time and low shrinkage are significant for concrete mixture to meet the critical requirements of a freeform construction process. Thereafter, measuring methods that can be employed to assess the fresh and hardened properties of concrete at early stages are suggested. Finally, a few of evaluation methods are presented which may offer certain assistance for optimizing material preparation. The objective of this work is to review current design methodologies and experimental measurement and evaluation methods for 3D printable concrete materials and promote its responsible use with largescale 3D printing technology.

关键词： 3D printing concrete material printable property workability measurement construction automation

Theoretical study on the mechanism of sulfur migration to gas in the pyrolysis of benzothiophene

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Frontiers of Chemical Science and Engineering 2023年第3期17卷 334-346页

作者： Ji Liu Shuang-Wei Yang Wei Zhao Yu-Long Wu Bin Hu Si-Han Hu Shan-Wei ma Qiang Lu National Engineering Research Center of New Energy Power Generation North China Electric Power UniversityBeijing 102206China Suzhou Institute of North China Electric Power University Suzhou 215000China Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China School of Chemistry and Chemical Engineering Xinjiang UniversityUrumqi City 830046China

The release and control of sulfur species in the pyrolysis of fossil fuels and solid wastes have attracted attention ***,thiophene derivatives are important intermediates for the sulfur gas release from organic sulfur,but the underlying migration mechanisms remain ***,the mechanism of sulfur migration during the release of sulfur-containing radicals in benzothiophene pyrolysis was explored through quantum chemistry *** C_(1)-to-C_(2)H-transfer has the lowest energy barrier of 269.9 kJ·mol-1 and the highest rate constant at low temperatures,while the elevated temperature is beneficial for C−S bond homolysis.2-Ethynylbenzenethiol is the key intermediate for the formation of S and SH radicals with the overall energy barriers of 408.0 and 498.7 kJ·mol-1 in favorable *** generation of CS radicals is relatively difficult because of the high energy barrier(551.8 kJ·mol-1).However,it can be significantly promoted by high temperatures,where the rate constant exceeds that for S radical generation above 930°***,the strong competitiveness of S and SH radicals results in abundant H2 S during benzothiophene pyrolysis,and the high temperature is more beneficial for CS2 generation from CS *** study lays a foundation for elucidating sulfur migration mechanisms and furthering the development of pyrolysis techniques.

关键词： benzothiophene sulfur migration pyrolysis density functional theory

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