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Simulation and model design of pipe-shell reactor for the direct synthesis of dimethyl ether from syngas

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Journal of Natural Gas Chemistry 2008年第2期17卷 195-200页

作者： Yanfang Hu Zhaoguang nie Dingye Fang College of Chemical Engineering and Environment Qingdao University Qingdao 266071 Shandong China Department of Chemical Engineering East China University Science and Technology Shanghai 200237 China

The simulation was made based on the model of pipe-shell reactor that was established by the model of global kinetics of synthesis of dimethyl ether from syngas over a bifunctional catalyst. The results of simulation showed that the selectivity for dimethyl ether （DME） and the conversion of CO were higher but the hot spot was kept below the temperature limit of the pipe-shell reactor. The suitable diameter of the pipe was φ38×2 mm, and the length of the pipe was 5.8 m. The optimal process conditions of the reactor were that the pressure was 5 MPa, the temperature of the cooling water was 240 ℃, and the temperature of the raw gas at inlet of the reactor was 220 ℃. The production of this reactor was 102800 t/y （ton per year） under these conditions.

关键词： simulation model dimethyl ether pipe-shell reactor syngas

The effect of pre-existing memory representations on repetitionrelated N250r and N400

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Science Bulletin 2016年第4期61卷 265-275页

作者： Aiqing nie Jingheng Ye Minye Li Department of Psychology and Behavior Science Zhejiang University

Studies of repetition priming have found two face-sensitive event-related potential(ERP) components:the N250 r showing positive deflection at frontal region and negative deflection at temporal region, and the N400 showing positive deflection at frontal and centro-parietal regions, both of which depend in part upon the presence or absence of a pre-existing face representation. However, the N250 r is rarely reported for a repetition interval between immediate repetition and 3 min; in addition, whether different types of representations function in the same way is also of interest. The goal of the present experiment is to compare the ERP patterns for faces versus letter strings as a function of the pre-existing memory representation with a repetition interval of 1.5 min on average. We found reliable frontally positive N250 r and N400 for famous faces and words; marginally significant effects for pseudo-words;and only the centro-parietal N400 for unfamiliar ***, the N250 r persists in the present intermediate intervals, and both the frontal N250 r and the frontal N400 are domain-general, sensitive to the pre-existing memory representation.

关键词： Repetition priming - Pre-existingmemory representation - Face - Letter string - N250rN400

Co-aperture arrangement of dual antennas for orientation and telemetry in a conformal cavity

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Journal of Systems Engineering and Electronics 2008年第6期19卷 1133-1138页

作者： Zong Xianzheng nie Zaiping Wang Jun School of Electronic Engineering Univ. of Electronic Science and Technology Chengdu 610054 P. R. China Inst. of Electronic Engineering Chinese Academy of Engineering Physics Mianyang 621900 P. R. China

The feasibility of making two antennas work within a shared aperture conformai to a platform like an aircraft or a missile is investigated. The shared aperture is enclosed by a deep cavity, which is covered by a columniform dielectric radome. A modified quadrifilar helix antenna （QHA） with extended volute arms and a vertical monopole with a ring shaped ground are arranged in this co-aperture for global position system （GPS） orientation and telemetry, respectively. The effects of the cavity on these two antennas and the mutual coupling between these two antennas are studied through large numbers of experiments. The results show that the QHA has a strong influence on the monopole; however, these two antennas of the overall arrangement can perform simultaneously well within the aperture. The QHA has a right hand circular polarization （RHCP） and a broad beam normal to the radome topside, meanwhile the monopole can be used to produce a main lobe in the grazing direction above the aperture in some certain cases of the vertical location of the QHA in the cavity.

关键词： antennas co-aperture cavity radome

Design and Dynamics Analysis of Anti-skid Braking System for Aircraft with Four-wheel Bogie Landing Gears

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Chinese Journal of Mechanical Engineering 2011年第2期24卷 277-284页

作者： ZHANG Ming nie Hong ZHU Rupeng Key Laboratory of Fundamental Science for National Defense-Advanced Design Technology of Flight Vehicle Nanjing University of Aeronautics and Astronautics Nanjing 210016 China College of Mechanical and Electrical Engineering Nanjing University of Aeronautics andAstronautics Nanjing 210016 China

In asymmetric conditions,the movement and loads of left/right wheels or front/back wheels of the aircraft with multi-wheel or four-wheel bogie landing gears are *** are few open literatures related to anti-skid braking system for multi-wheels due to technology *** China,the research on multi-channel control and non-equilibrium regulation has just started,and the design of multi-channel control system for anti-skid braking,the simulation of asymmetry taxiing under braking are not *** this paper,a dynamics model of ground movement for aircraft with four-wheel bogie landing gears is established for braking simulation, considering the six-degree-of-freedom aircraft body and the movement of bogies and wheels.A multi-channel anti-skid braking system is designed for the wheels of the main landing gears with four-wheel *** eight wheels on left and right landing gears are divided into four groups,and each group is controlled via one *** cross protection and self-locked protection modules are added between different channels.A multi-channel anti-skid braking system with slip-ratio control or with slip-velocity control is established *** on the aircraft dynamics model,aircraft braking to stop with anti-skid control on dry runway and on wet runway are *** simulation results demonstrate that in asymmetric conditions,added with cross protection and self-locked protection modules,the slip-ratio-controlled braking system can automatically regulate brake torque to avoid deep slipping and correct aircraft *** proposed research has reference value for improving brake control effect on wet runway.

关键词： anti-skid braking system four-wheel bogie landing gear multi-channel control dynamics model

A New Credit Spread to Predict Economic Activities in China

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Journal of Systems Science & Complexity 2019年第4期32卷 1140-1166页

作者： WANG Lei nie Changhong WANG Shouyang School of Economics and Management University of Chinese Academy of SciencesBeijing 100190China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China

In recent years,the relationship between bond spreads and macro economy has been studied extensively by economists in western ***,few attentions were paid on this topic in *** essay regards Chinese bond market as a complex system and constructs bond indices for China with the bottom-up *** authors use the data of 3,205 non-financial corporate bonds from February 2010 to October 2017 and construct a new spread noted as the PE SOE *** authors find that the PESOE spread has a negative impact on economic activities and has the best predictive ability at short-run forecasting horizons,owing to the institutional superiority of the stateowned enterprises in *** Treasury bond yields are found to have the best predictive ability at long-run *** spread shock and Treasury yield shock could lead to deflation and declines in economic activities,and the Treasury yield shock has a more severe and persistent impact on the economy due to the financial accelerator *** spread is proved to be a better indicator for Chinese corporate bond market and can be widely used not only in future Chinese economic studies,but also for Chinese government’s macroeconomic monitoring and warning.

关键词： Chinese bond market corporate bond spreads credit spreads financial accelerator private enterprises state-owned enterprises

Experimental and Numerical Analysis of the Uniaxial Tensile Properties of F321 Austenitic Stainless Steel at Different Temperatures

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Acta Mechanica Solida Sinica 2022年第3期35卷 409-420页

作者： Meidan Liu Junfeng nie Pandong Lin Institute of Nuclear and New Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China

F321 austenitic stainless steel,well known for its excellent corrosion and oxidation resistance,is widely used as a structural component in the pipelines and pumps of light water reactors(LWRs)and generation IV(GenlV)***,the material failure arising from the high-temperature softening of the 300 series austenitic stainless steels has recently received significant *** this study,we conducted uniaxial tensile tests on F321 stainless steel at different temperatures.P\irthermore,we developed a face-centered cubic(FCC)crystal plasticity method emphasizing the temperature factor of the evolution of dislocations inferred by the physical mechanisms at the microscopic level to simulate the polycrystalline mechanical response and model the high-temperature softening phenomenon of F321 austenitic stainless ***,this model was implemented using the ABAQUS finite-element *** this basis,the crystal plastic finite-element method(CPFEM)of F321 stainless steel was *** calculated results were in good agreement with the experimental results,which validated the effectiveness of this numerical method.

关键词： Uniaxial tensile properties F321 austenitic stainless steel Crystal plastic finite-element method

Flat-band ferromagnetism of SU(N) Hubbard model on Tasaki lattices

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Science Bulletin 2019年第20期64卷 1490-1495页

作者： Ruijin Liu Wenxing nie Wei Zhang Department of Physics Renmin University of ChinaBeijing100872China Center for Theoretical Physics College of PhysicsSichuan UniversityChengdu610064China Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devices Renmin University of ChinaBeijing100872China

We investigate the para-ferro magnetic transition of the repulsive SU(N) Hubbard model on a type of oneand two-dimensional decorated cubic lattices, referred as Tasaki lattices, which feature massive singleparticle ground state degeneracy. Under certain restrictions for constructing localized many-particle ground states of flat-band ferromagnetism, the quantum model of strongly correlated electrons is mapped to a classical statistical geometric site-percolation problem, where the nontrivial weights of different configurations must be considered. We prove rigorously the existence of para-ferro transition for the SU(N) Hubbard model on one-dimensional Tasaki lattice and determine the critical density by the transfer-matrix method. In two dimensions, we numerically investigate the phase transition of SU(3),SU(4) and SU(10) Hubbard models by Metropolis Monte Carlo simulation. We find that the critical density exceeds that of standard percolation, and increases with spin degrees of freedom, implying that the effective repulsive interaction becomes stronger for larger N. We further rigorously prove the existence of flat-band ferromagnetism of the SUeNT Hubbard model when the number of particles equals to the degeneracy of the lowest band in the single-particle energy spectrum.

关键词： SU(N) Flat-band ferromagnetism Percolation Para-ferro transition

Chemoselective epoxidation of electron-deficient olefins with molecular oxygen via conjugated olefins epoxidation and BHT hydroxylation

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Science China Chemistry 2024年第9期67卷 3012-3018页

作者： Jia nie Huanfeng Jiang Chuanle Zhu School of Chemistry and Chemical Engineering Key Lab of Functional Molecular Engineering of Guangdong ProvinceSouth China University of TechnologyGuangzhou 510640China Guangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced Manufacturing South China University of TechnologyGuangzhou 510640China

The chemoselective epoxidation of electron-deficient olefins in the presence of electron-rich alkene moieties is *** chemoselective epoxidation strategy undergoes a conjugated olefin epoxidation and BHT hydroxylation process to give various useful oxiranes in high yields,especially for the 2-substituted ***,this protocol features mild conditions,is transition-metal free,operationally simple,and gram-scalable,and tolerates diverse functional *** candidate HSD-16 is synthesized smoothly by this *** studies indicate molecular oxygen is the terminal oxidant and the O-source of the oxiranes.

关键词： chemoselective epoxidation alkene fluorine molecular oxygen

Computational Research on Rotating Channel by a Modified Anisotropic Turbulence Model

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Journal of Thermal Science 2011年第5期20卷 385-393页

作者： Jianqin Zhu Zhi Tao Chaoqun nie Institute of Engineering Thermophysics Chinese Academy of Science Beijing 100190 China National Key Lab. on Aero-Engines School of Jet Propulsion Beihang University Beijing 100191.China

Based on the simplified format of the Reynolds stress equations, a fire-new rotational-modification method for the anisotropic turbulence model has been presented. A three-dimensional Navier-Stokes code with this new rotational modified k-ω turbulence models （β=0.1 and β=1） and the standard k-ω turbulence model have been used for the prediction of flow and heat transfer characteristics in a rotating smooth square channel. The Reynolds number Re based on the inlet velocity of the cooling air and hydraulic diameter is 6000 .The rotating speed are 300, 600, 900, 1200rpm respectively. The calculations results of using three turbulence models have been compared with the experimental data. The research results show that （1） the rotational modification coefficient Rf13 used in the new anisotropic k-ω model would increased/decreased the predictions of heat transfer on the trailing surface/leading surface compared to the standard k-ω model. And this tendency would be increased with the increased ft. （2） The simulation performance of the standard k-ω model was well on the leading surface. However, on the trailing surface it under-predicted the heat transfer at high rotating speed. （3） The calculation results of the new anisotropic k-ω model with β=0.1 proposed by the present paper agreed well with experimental data, both on the leading and trailing surfaces. Besides, compared to 1, 0.1 is a more appropriate magnitude of βat conditions in the present paper.

关键词： anisotropy turbulence model rotation heat transfer