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Capacity evaluation of the backhaul link in the outdoor relay system at 2.35GHz

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High Technology Letters 2012年第4期18卷 401-405页

作者：张建华 Zhang Fenghua Nie Xin Huang chengxiang Key Laboratory of Universal Wireless Communications Ministry of Education Beijing 100876 P. R. China Wireless Technology Innovation Institute Beijing University of Posts and Telecommunications Beijing 100876 P. R. China

A measurement campaign has been conducted at 2.35 GHz with a bandwidth of 50 MHz to ob- tain the statistics and evaluate the capacity of the backhaul link. Based on the measured channel im- pulse response, the channel gain, the eigenvalue statistics and the capacity are investigated. The distribution and corresponding parameters for describing the eigenvalue dispersion, the maximum and minimum eigenvalues are given. It is found that the backhaul link is relatively stable, which shows small variance of the channel gain. In spite of the fact that there are not many scatterers in the backhaul link, the channel rank can be enhanced by using dual-polarized antennas. Thus, the backhaul link can provide enough capacity.

关键词： relay channel measurement wideband MIMO channel channel gain eigenvaluestatistics capacity

Finite-Size Scaling Theory at a Self-Dual Quantum Critical Point

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Chinese Physics Letters 2023年第1期40卷 14-18页

作者：张龙丁成祥 Kavli Institute for Theoretical Sciences and CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100190China School of Microelectronics&Data Science Anhui University of TechnologyMaanshan 243002China

The nondivergence of the generalized Gr¨uneisen ratio(GR)at a quantum critical point(QCP)has been proposed to be a universal thermodynamic signature of *** study how the Kramers–Wannier-type self-duality manifests itself in the finite-size scaling behavior of thermodynamic quantities in the quantum critical *** the self-duality cannot be realized as a unitary transformation in the total Hilbert space for the Hamiltonian with the periodic boundary condition,it can be implemented in certain symmetry sectors with proper boundary ***,the GR and the transverse magnetization of the one-dimensional transversefield Ising model exhibit different finite-size scaling behaviors in different *** implies that the numerical diagnosis of self-dual QCP requires identification of the proper symmetry sectors.

关键词： duality symmetry transverse

A dynamic evaluation technique for assessing gas output from coal seams during commingling production within a coalbed methane well: a case study from the Qinshui Basin

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International Journal of Coal Science & Technology 2020年第1期7卷 122-132页

作者： Chuan Wu chengxiang Yuan Guojun Wen Lei Han Haojie Liu School of Mechanical and Electronic Information China University of Geosciences(Wuhan)Wuhan 430074China Hubei Intelligent Geological Equipment Engineering Technology Research Center Wuhan 430074China Key Laboratory of Tectonics and Petroleum Resources(China University of Geosciences)Ministry of Education Wuhan 430074China

Gas drainage is carried out based on output from each coal bed throughout commingling production of coalbed methane(CBM).A reasonable drainage process should therefore initially guarantee main coal bed production and then enhance gas output from other *** damage can result if this is not the case,especially with regard to fracture development in the main gas-producing coal bed and can greatly reduce single well *** theoretical models and measuring devices are inapplicable to commingled CBM drainage,however,and so large errors in predictive models cannot always be *** most effective currently available method involves directly measuring gas output from each coal bed as well as determining the dominant gas-producing unit.A dynamic evaluation technique for gas output from each coal bed during commingling CBM production is therefore proposed in this *** technique comprises a downhole measurement system combined with a theoretical calculation *** output parameters(i.e.,gas-phase flow rate,temperature,pressure)are measured in this approach via a downhole measurement system;substituting these parameters into a deduced theoretical calculation model then means that gas output from each seam can be calculated to determine the main gas-producing *** in gas output from a single well or each seam can therefore be *** laboratory and field test results presented here demonstrate that calculation errors in CBM outputs can be controlled within a margin of 15%and therefore conform with field use requirements.

关键词： Commingling production Gas output Dynamic evaluation Coalbed methane Qinshui Basin

Chiral phenethylamine synergistic tricarboxylic acid modified β-cyclodextrin immobilized on porous silica for enantioseparation

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Chinese Chemical Letters 2023年第3期34卷 162-165页

作者： Hui Li Xiaoping Wang chengxiang Shi Liang Zhao Zuguang Li Hongdeng Qiu CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China College of Chemical Engineering Zhejiang University of TechnologyHangzhou 310014China

In this work, a series of chiral phenethylamine synergistic tricarboxylic acid modified β-cyclodextrin bonded stationary phase for high performance liquid chromatography(HPLC) were synthesized via a simple one-pot synthesis approach. Various racemates(aryl alcohols, flavanones, triazoles, benzoin, etc.) were well separated on the tricarboxylic acid modified chiral stationary phases in both normal and reversed modes with good reproducibility and stability, and the influence of mobile phase composition on resolution(R_(s)) were deeply investigated. The RSD values of Rsfor repeatability and column-to-column were below 1.28% and 3.05%, respectively. Hence, the fabrication of tricarboxylic acid modified chiral stationary phase(CSPs) is a new efficient strategy to improve the application of β-cyclodextrin as CSPs in the field of chromatography.

关键词： Tricarboxylic acid β-cyclodextrin Chiral stationary phases Enantioseparation One-pot strategy

10 kV nanosecond pulse generator with high voltage gain and reduced switches

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High Voltage 2024年第5期9卷 1059-1067页

作者： Jiuxin Ma Liang Yu Chenguo Yao Shoulong Dong chengxiang Li Lvheng Ren Shixin Wang National Key Laboratory of Power Transmission and Transformation Equipment Technology School of Electrical EngineeringChongqing UniversityChongqingChina

In the article,a new type boost high-voltage nanosecond pulse generator is *** distributed inductance of the transmission line is utilised as the energy storage unit and cooperated with the variable impedance transmission line transformer to generate nanosecond pulses with extremely high-voltage ***’s more,the isolation effect caused by the transmission line time delay is applied to achieve modular *** demand for charging power supply can be greatly reduced,and few switches are ***,the topological principle is verified by experiments,and a prototype of the fivestage stacking prototype is *** the charging voltage of 28 V,the generator can output pulse with a voltage amplitude of 10 kV and pulse width of 12 ns whose voltage gain is up to 357 times.

关键词： pulse generator charging

Conversion of lignin oil and hemicellulose derivative into high-density jet fuel

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Journal of Energy Chemistry 2023年第2期77卷 452-460,I0012页

作者： Sichao Yang chengxiang Shi Zhensheng Shen Lun Pan Zhenfeng Huang Xiangwen Zhang Ji-Jun Zou Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Collaborative Innovative Center of Chemical Science and Engineering(Tianjin) Tianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China

Synthesizing high-density fuel from lignocellulose can not only achieve green and low-carbon development,but also expand the feedstock source of hydrocarbon ***,we reported a route of producing high-density fuel from lignin oil and hemicellulose derivative cyclopentanol through alkylation and hydrodeoxygenation,HY with SiO_(2)/Al_(2)O_(3) molar ratio of 5.3 was screened as the alkylation catalyst in the reaction of model phenolic compounds and mixtures,and the reaction conditions were optimized to achieve conversion of phenolic compounds higher than 87%and selectivity of bicyclic and tricyclic products higher than 99%.Then two phenolic pools simulating the composition of two typic lignin oils were studied to validate the alkylation and analyze the competition mechanism of phenolic compounds in mixture ***,real lignin oil from depolymerized of beech powder was tested,and notably80%of phenolic monomers in the oil were converted into fuel *** hydrodeoxygenation,the alkylated product was converted to fuel blend with a density of 0.91 g/mL at 20℃and a freezing point lower than-60℃,very promising as high density *** work provides a facile and energyefficient way of synthesizing high-performance jet fuel directly from lignocellulosic derivatives,which decreases processing energy consumption and improve the utilization rate of feedstock.

关键词： High-density fuel Biofuel Lignin oil Alkylation Hydrodeoxygenation

Metal-oxoacid-mediated oxyhydroxide with proton acceptor to break adsorption energy scaling relation for efficient oxygen evolution

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Journal of Energy Chemistry 2023年第5期80卷 594-602,I0013页

作者： Rongrong Zhang Beibei Guo Lun Pan Zhen-Feng Huang chengxiang Shi Xiangwen Zhang Ji-Jun Zou Key Laboratory for Green Chemical Technology of the Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityBinhai New CityFuzhou 350207FujianChina Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China

Metal oxyhydroxides(MOOH)generated from irreversible reconstructions of transition metal compounds are intrinsic active species for oxygen evolution reaction,whose activities are still constrained by sluggish deprotonation kinetics and inherent adsorption energy scaling ***,we construct a tunable proton acceptor(TPA)on oxyhydroxides by in-situ reconstruction of metal oxoacids such as NiC2O4to accelerate deprotonation and break adsorption energy scaling relations during *** modified C_(2)O_(4)^(2-)as a TPA can easily extract H of*OH(forming*HC2O4intermediate)and then promote deprotonation by the transmitted hydrogen bond with*OOH along conjugated(H...)O=C-O(-H)*** a result,Ni OOH-C2O4shows non-concerted proton-electron transfer and improved deprotonation rate,and delivers a good OER activity(270 mV@10 mA cm-2).The conjugate acidity coefficient(pKa)of the modified oxoacid group can be a descriptor for TPA *** TPA strategy can be universally applied to Co-,Fe-,and Ni-based oxyhydroxides to facilitate OER efficiency.

关键词： Electrocatalysis Metal oxyhydroxide Oxoacid group Tunable proton acceptor Oxygen evolution reaction

Shadows of magnetically charged rotating black holes surrounded by quintessence

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Chinese Physics C 2022年第6期46卷 246-256页

作者： chengxiang Sun Yunqi Liu Wei-Liang Qian Ruihong Yue Center for Gravitation and Cosmology College of Physical Science and TechnologyYangzhou UniversityYangzhou 225009China Escola de Engenharia de Lorena Universidade de Sao Paulo12602-810LorenaSPBrazil School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China Faculdade de Engenharia de Guaratingueta Universidade Estadual Paulista12516-410GuaratingueiaSPBrazil

In this work,we study the optical properties of a class of magnetically charged rotating black hole *** black holes in question are assumed to be immersed in the quintessence field,and subsequently,the resulting black hole shadows are expected to be modified by the presence of dark *** investigate the photon region and the black hole shadow,especially their dependence on the relevant physical conditions,such as the quintessence state parameter,angular momentum,and magnetic charge *** photon regions depend sensitively on the horizon structure and possess intricate ***,from the viewpoint of a static observer,we explore a few observables,especially those associated with the distortion of the observed black hole shadows.

关键词： black hole shadow quintessence magnetically charged rotating black hole

Artificial Intelligence Based Multi-Scenario mmWave Channel Modeling for Intelligent High-Speed Train Communications

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China Communications 2024年第3期21卷 260-272页

作者： Zhang Mengjiao Liu Yu Huang Jie He Ruisi Zhang Jingfan Yu Chongyang Wang chengxiang School of Microelectronics Shandong UniversityJinan 250101China The State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong UniversityBeijing 100044China The National Mobile Communications Research Laboratory School of Information Science and EngineeringSoutheast UniversityNanjing 210096China The Purple Mountain Laboratories Nanjing 211111China

A large amount of mobile data from growing high-speed train(HST)users makes intelligent HST communications enter the era of big *** corresponding artificial intelligence(AI)based HST channel modeling becomes a *** paper provides AI based channel characteristic prediction and scenario classification model for millimeter wave(mmWave)HST ***,the ray tracing method verified by measurement data is applied to reconstruct four representative HST *** setting the positions of transmitter(Tx),receiver(Rx),and other parameters,the multi-scenarios wireless channel big data is ***,based on the obtained channel database,radial basis function neural network(RBF-NN)and back propagation neural network(BP-NN)are trained for channel characteristic prediction and scenario ***,the channel characteristic prediction and scenario classification capabilities of the network are evaluated by calculating the root mean square error(RMSE).The results show that RBF-NN can generally achieve better performance than BP-NN,and is more applicable to prediction of HST scenarios.

关键词： artificial intelligence channel characteristic prediction HST channel millimeter wave scenario classification