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Simulation experiment of AE-based localization damage and deformation characteristic on covering rock in mined-out area

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International Journal of Minerals,Metallurgy and Materials 2009年第3期16卷 255-260页

作者： Sheng-jun Miao Xing-ping lai Xing-guang Zhao Fen-hua Ren School of Civil ＆ Environmental Engineering University of Science and Technology Beijing Beijing 100083 China School of Energy Engineering Xi＇an University of Science and Technology Xi＇an 710054 China

The localization damage and deformation characteristics of multiple rock in mined-out area under thick soil layer were investigated by acoustic emission （AE）-based physical similar simulation experiment and damage test combined with the AE theory on rock damage. During different mining courses, the degree of wall rock suffered from mining disturbed process in mined-out area was different, so did the AE density of initial damage and fracture. Some characteristic parameters, including large events, total events, and energy rate, presented fluctuations with temporal and spatial change and take on a certain extent statistic relation. Subsequently, the percent of damage degree was defined and divided into 4 stages, and the localization damage and deformation characteristics of surrounding rock in mined-out area and coal pillars were analyzed quantitatively.

关键词： acoustic emission soil layer underground mine rock damage in-site monitoring

High-order harmonic generation in a two-color strong laser field with Bohmian trajectory theory

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Chinese Physics B 2018年第7期27卷 295-300页

作者： Yi-Yi Huang Xuan-Yang lai Xiao-jun Liu State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences. Wuhan 430071 China University of Chinese Academy of Sciences Beijing 100049 China

We theoretically study the high-order harmonic generation （HHG） in a two-color laser field using the Bohmian mechanics. Our results show that, for tile case of a weak second-color laser field, the simulation of the HHG with only one central Bohmian trajectory is in a good agreement with the ab initio time-dependent Schrodinger equation （TDSE） results. In contrast, with the increase of the amplitude of the second-color laser field, the HHG spectra from the single central Bohmian trajectory deviate from the TDSE results more and more significantly. By analyzing the Bohmian trajectories, we find that the significant deviation is due to the fact that the central Bohmian trajectory leaves the core quickly in the two-color laser field with the breaking of inversion symmetry. Interestingly, we find that another Bohmian trajectory with different initial position, which keeps oscillating around the core, could qualitatively well reproduce the TDSE results. Furthermore, we study the HHG spectrum in a two-color laser field with inversion symmetry and find that the HHG spectrum in TDSE can be still well simulated with the central Bohmian trajectory. These results indicate that, similar to the case of one color laser field, the HHG spectra in a two-color laser field can be also reproduced with a single Bohmian trajectory, although the initial position of the trajectory is dependent on the symmetry of the laser field. Our work thus demonstrates that Bohmian trajectory theory can be used as a promising tool in investigating the HHG process in a two-color laser field.

关键词： high-order harmonic generation two-color laser field Bohmian trajectory

Energy harvester array using piezoelectric circular diaphragm for rail vibration

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Acta Mechanica Sinica 2014年第6期30卷 884-888页

作者： Wei Wang Rong-Jin Huang Chuan-jun Huang lai-Feng Li State Key Laboratory of Technologies in Space Cryogenic Propellants Technical Institute of Physics and ChemistryChinese Academy of Sciences

Generating electric energy from mechanical vibration using a piezoelectric circular membrane array is presented in this *** electrical characteristics of the functional array consisted of three plates with varies tip masses are examined under dynamic *** an optimal load resistor of 11 k,an output power of 21.4 m W was generated from the array in parallel connection at 150 Hz under a pre-stress of 0.8 N and a vibration acceleration of9.8 m/***,the broadband energy harvesting using this array still can be realized with different tip *** obvious output power peaks can be obtained in a frequency spectra of 110 Hz to 260 *** results show that using a piezoelectric circular diaphragm array can increase significantly the output of energy compared with the use of a single *** by optimizing combination of tip masses with piezoelectric elements in array,the frequency range can be tuned to meet the broadband *** array may possibly be exploited to design the energy harvesting for practical applications such as future high speed rail.

关键词： Energy harvesting Array Piezoelectric material Rail vibration

Effects of heat treatment on the microstructures and mechanical properties of a new type of nitrogen-containing die steel

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International Journal of Minerals,Metallurgy and Materials 2012年第6期19卷 511-517页

作者： Jing-yuan Li Peng Zhao jun Yanagimoto Sumio Sugiyama Yu-lai Chen School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Institute of Radar and Avionics Aviation Industry Corporation of China Suzhou 215151 China Institute of Industrial Science the University of Tokyo Tokyo 153-8505 Japan Engineering Research Institute University of Science and Technology Beijing Beijing 100083 China

Nitrogen can increase the strength of steels without weakening the toughness and improve the corrosion resistance at the same time. Compared with conventional nitrogen-free die steels, a new type of nitrogen-containing die steel was developed with many superior properties, such as high strength, high hardness, and good toughness. This paper focused on the effects of heat treatment on the microstruc- tures and mechanical properties of the new type of nitrogen-containing die steel, which were investigated by the optimized deformation process and heat treatment. Isothermal spheroidal annealing and high-temperature quenching as well as high-temperature tempering were ap- plied in the experiment by means of an orthogonal method after the steel was multiply forged. The mechanical properties of nitro- gen-containing die steel forgings are better than the standard of NADCA #207-2003.

关键词： die steels nitrogen heat treatment microstructure mechanical properties forgings

The electrochemical advanced oxidation processes coupling of oxidants for organic pollutants degradation: A mini-review

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Chinese Chemical Letters 2019年第12期30卷 2139-2146页

作者： jun Li Yangju Li Zhaokun Xiong Gang Yao Bo lai State Key Laboratory of Hydraulics and Mountain River Engineering College of Architecture and EnvironmentSichuan UniversityChengdu 610065China Sino-German Centre for Water and Health Research Sichuan UniversityChengdu 610065China Institute of Environmental Engineering RWTH Aachen UniversityAachen 52072Germany

The electrochemical advanced oxidation processes(EAOPs) have been extensively applied in the treatment of organic pollutants ***,the mini review provides the coupling systems about EAOPs and different oxidants(e.g.,persulfate(PS),peroxymonosulfate(PMS),and ozone(O3)),including EAOPs-PS systems,EAOPs-PMS systems,EAOPs-peroxone systems,and photoelectro-oxidants systems,for the organic compounds *** coupling system of EAOPs with oxidants is an effective way to improve the generated free radicals(e.g.,HO^·and SO4^·-) concentration and to accelerate pollutant *** this review,we make a summary of the homogeneous and heterogeneous EAOPs-oxidant *** reaction mechanisms of EAOPs combined with different oxidants are elucidated in detail,as well as the synergistic effect for improving the degradation and mineralization efficiency.

关键词： Electrochemical advanced oxidation processes Organic compounds Oxidants Free radicals Reaction mechanism

UiO-66 framework equipped with cadmium-thiocatecholato moieties as photocatalyst bearing stable active sites and intrinsic photosensitizing units for hydrogen evolution reaction

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Chinese Journal of Structural Chemistry 2023年第6期42卷 41-46页

作者： Gui-Qi lai Zhixin Jiang Hao Zhong lai-Hon Chung Ning Li jun He School of Chemical Engineering and Light Industry Guangdong University of TechnologyGuangzhou510006PR China

Photocatalytic hydrogen evolution reaction(HER)represents one of the most promising technologies for sus-tainable *** though metal-organic framework(MOF),comprising rich topologies and tunable functionalities,is getting attention as a new generation of photocatalyst,a majority of them only provide unclear active sites along with the use of external noble-metal based photosensitizers and environmentally unfriendly ***,it is urged to develop MOFs possessing structurally unambiguous active sites along with inherent photosensitizing units and execute photocatalytic HER with greener sacrificial ***,we report a UiO-66-type framework,namely UiO-66-dcbdt-Cd(dcbdt^(2-)=1,4-dicarboxylatebenzene-2,3-dithiol),bearing Cd-thiocatecholato moieties as intrinsic photosensitizing units and structurally well-defined active sites for photocatalytic HER in H_(2)***-66-dcbdt-Cd gave the best HER yield of 5.29 mmol g^(-1)and rate of 1.32 mmol g^(-1)h^(-1),outperforming the negligible HER performance of pristine metal-free *** work provides insight to manipulation of thhiocatecholate functionalities inside MOFs to construct inherent photosensitizing units as well as stable structurally unambiguous active sites for sustainable photocatalytic applications.

关键词： UiO-66 framework Metal-thiocatecholato Photocatalytic hydrogen evolution Inherent photosensitizer

Event-triggered Control of Positive Switched Systems with Actuator Saturation and Time-delay

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International Journal of Automation and computing 2021年第1期18卷 141-154页

作者： jun-Feng Zhang lai-You Liu Shi-Zhou Fu Shuo Li School of Automation Hangzhou Dianzi UniversityHangzhou 310018China Inria University of LilleLille 59000France

This paper investigates the event-triggered control of positive switched systems with randomly occurring actuator saturation and time-delay,where the actuator saturation and time-delay obey different Bernoulli ***,an event-triggering con-dition is constructed based on a 1-norm *** the presented event-triggering scheme,an interval estimation method is utilized to deal with the error term of the *** a co-positive Lyapunov functional,the event-triggered controller and the cone attraction domain gain matrices are designed via matrix decomposition *** positivity and stability of the resulting closed-loop systems are reached by guaranteeing the positivity of the lower bound of the systems and the stability of the upper bound of the systems,*** proposed approach is developed for interval and polytopic uncertain systems,***,two examples are provided to illustrate the effectiveness of the theoretical findings.

关键词： Positive switched systems event-triggered control randomly occurring actuator saturation linear programming time-delay

Multi-dimensional controllability analysis of precision ball bearing integrity

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Advances in Manufacturing 2023年第4期11卷 682-693页

作者： lai Hu jun Zha Wei-Hua Zhao Xiao-Fei Peng Yao-Long Chen School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an710049People’s Republic of China State Key Laboratory for Manufacturing Systems Engineering Xi’an Jiaotong UniversityXi’an710054People’s Republic of China Luoyang Bearing Science and Technology Co. Ltd.Luoyang471039HenanPeople’s Republic of China

Many factors affect the integrity of precision ball *** this study,the multi-dimensional controllability of precision ball bearings produced in different company brands(bearing A and bearing B)were studied and *** geometric errors(flatness,parallelism,roundness and cylindricity of inner and outer rings,roundness,groove and roughness of inner and outer rings)and vibration errors of bearings were ***,the residual stress,residual austenite content,element content ratio,metamorphic layer and temperature-vibration displacement coupling test were also *** on the above analysis conclusion,the bearing fatigue life test was carried out for 2150 *** reliability of the conclusion is proved again as *** the residual austenite content in the raceway of precision ball bearing is 10%,the axial residual stress is 877.4 MPa;the tangential residual stress is 488.1 MPa;the carbon content is 6%;the test temperature of bearing is the lowest;and the service life is prolonged.

关键词： Precision ball bearing Controllability Geometric errors Carbon content Residual austenite Residual stress

Spontaneous coronary dissection should not be ignored in patients with chest pain in autosomal dominant polycystic kidney disease:A case report

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World Journal of Clinical Cases 2021年第13期9卷 3095-3101页

作者： jun Qian Yan lai Li-jun Kuang Fei Chen Xue-Bo Liu Department of Cardiology Tongji HospitalTongji University School of MedicineShanghai 200065China Department of Ultrasound Luwan BranchRuijin HospitalShanghai Jiao Tong University School of MedicineShanghai 200065China

BACKGROUND When autosomal dominant polycystic kidney disease(ADPKD)presents with acute coronary syndrome(ACS),the possibility of spontaneous coronary artery dissection(SCAD)should be highly *** some cases,SCAD is considered an extrarenal manifestation of ADPKD depending on the pathological characteristics of the unstable arterial wall in *** SUMMARY Here,we report a 46-year-old female patient with ADPKD who presented with *** angiography revealed no definite signs of dissection,while intravascular ultrasound revealed a proximal to distal dissection of the left *** a careful conservative medication treatment,the patient exhibited favorable *** In cases of ADPKD co-existing with ACS,differential diagnosis of SCAD should be ***,when no clear dissection is found on coronary angiography,IVUS should be performed to prevent missed diagnosis.

关键词： Spontaneous coronary artery dissection Autosomal dominant polycystic kidney disease Intravascular ultrasound Case report