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Rock dynamics in deep mining

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International Journal of Mining Science and Technology 2023年第9期33卷 1065-1082页

作者： Manchao He qi Wang State Key Laboratory for Geo-mechanics and Deep Underground Engineering China University of Mining&Technology-BeijingBeijing 100083China

Rock mass dynamics disasters caused by excavations and mining occur frequently in deep *** order to establish a theoretical system and control technologies for such disasters,we first classify and define dynamic disasters,such as rock bursts,coal bursts,mine pressure bumps,and mine *** to the occurrence mechanism of different types of dynamic disasters,we establish a compensation control theory based on excavation and mining *** the basis,we propose three key technologies:high prestress compensation technology for the roadway,pressure relief technology using directional roof cutting,and the goaf filling technology using broken rock *** three technologies constitute the compensation control method for dynamic disasters in deep ***,this method was successfully applied in a deep coal mine with high stress,with monitored results suggesting its *** work provides a new concept and control method for the prevention of rock dynamic disasters in deep mines.

关键词： Rock burst Coal burst Mine pressure bump Mine earthquake Excavation compensation control Mining compensation control

Hydrothermal preparation of Nb-doped NaTaO_(3) with enhanced photocatalytic activity for removal of organic dye

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Chinese Journal of Chemical Engineering 2022年第6期35卷 142-149页

作者： Hao Zhou qi Yin State Key Laboratory of Clean Energy Utilization Zhejiang UniversityHangzhou 310027China

The construction of efficient photocatalysts has received much attention in wastewater *** this study,Nb-doped NaTaO_(3) was prepared with different doping ratio by a facile hydrothermal *** prepared catalysts were analyzed by X-ray diffraction,scanning electron microscopy,Brunauer-EmmettTeller(BET)theory,ultraviolet–visible diffuse reflectance *** the synthesized catalysts were employed to degrade a model pollutant,methylene blue(MB),under a 250 W mercury *** characterization tests confirm that Nb was successfully doped into the crystal structure of NaTaO_(3) and the modified NaNb_(x)Ta_(1)·xO_(3)(x is the doping ratio;x=0.25,0.5,0.75)samples were formed,which were in regular cubic shapes just like pure NaTaO_(3).The synthesized NaNb_(x)Ta_(1)·xO_(3)(x=0.25,0.5,0.75)had improved specific surface area and narrowed band gaps compared with pure NaTaO_(3).In photocatalytic degradation experiments,NaNb0.75Ta0.25O_(3) presented the best photocatalytic activity ascribed to the narrow band gap and the high surface area,degradating 95.7%of MB after 180 min of reaction,which was even twice the ability of pure NaTaO_(3).Besides,the effects of possible inorganic anions and cations in wastewater on photocatalytic degradation were *** spin resonance(ESR)tests and capture experiments were also conducted and a possible photocatalytic mechanism was *** work provides a direction for constructing superior NaTaO_(3)-based photocatalysts to be widely utilized in environmental protection.

关键词： Photocatalytic degradation Methylene blue NaTaO_(3)

Kinetic roles of vibrational excitation in RF plasma assisted methane pyrolysis

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Journal of Energy Chemistry 2019年第12期28卷 188-197页

作者： Jintao Sun qi Chen School of Mechanical Electronic and Control Engineering Beijing Jiaotong University

A combined experimental and simulational work was carried out in this paper to investigate the kinetic effects of non-equilibrium excitation by direct electron impact on low temperature pyrolysis of CH4 in a RF dielectric barrier *** attention was placed on the vibrational chemistry of CH4 and some other important products including H2,C2H2,C2H4,C2H6 and C3H8 largely produced in CH4/He discharge under an intermediate reduced electric field ranging 51-80 Td.A detailed kinetic mechanism incorporating a set of electron impact reactions,electron-ion recombination reactions,negative ions attachment reactions,charge exchange reactions,reactions involving vibrationally excited molecules and the relaxation process of vibrationally excited species was assembled and experimentally *** modeling results showed a reasonable agreement with the experimentally measured results in terms of CH4 conversion and products production including C2 hydrocarbons and hydrogen.A linear increasing trend of methane conversion with increasing plasma power input was discovered,which suggested a strong dependence of molecular excitation on energy *** the CH4/He mole ratio and the reactor temperature play significant roles in CH4 conversion and major products *** experimental results showed that the selectivity of value-added products C2H4 and H2 keeps essentially unchanged with increasing energy input,mostly because the contribution CH4 ionization and He excitation effectively compete with vibrational excitation and dissociation of CH4 molecule with the E/N value *** calculated results showed that the typical relaxation time of vibrational states is comparable to the gas-kinetics time in a CH4/He discharge mixture,thus the vibrationally excited molecules can significantly accelerate chemical reactions through an effective decrease of activation *** path flux analysis revealed that the vibrationally excited molecules CH4(v)and H2(v)enhanced

关键词： Non-equilibrium plasma Methane pyrolysis Vibrational excitation Path flux analysis Sensitivity analysis

Certificateless threshold signature from lattice

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Digital Communications and Networks 2024年第4期10卷 965-972页

作者： Huifang Yu qi Zhang School of Cyberspace Security Xi'an University of Posts and TelecommunicationsXi'anChina

Threshold signature has been widely used in electronic wills,electronic elections,cloud computing,secure multiparty computation and other *** now,certificateless threshold signature schemes are all based on traditional mathematic theory,so they cannot resist quantum computing *** view of this,we combine the advantages of lattice-based cryptosystem and certificateless cryptosystem to construct a certificateless threshold signature from lattice(LCLTS)that is efficient and resistant to quantum algorithm *** has the threshold characteristics and can resist the quantum computing attacks,and the analysis shows that it is unforgeable against the adaptive Chosen-Message Attacks(UF-CMA)with the difficulty of Inhomogeneous Small Integer Solution(ISIS)*** addition,LCLTS solves the problems of the certificate management through key escrow.

关键词： Lattice Threshold signature Inhomogeneous small integer solution Certificateless public key Lattice sampling technique

Quantitative Assessment for Commutation Security Based on Extinction Angle Trajectory

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Journal of Modern Power Systems and Clean Energy 2021年第2期9卷 328-337页

作者： qi Tao Yusheng Xue the School of Electrical Engineering Zhejiang UniversityHangzhou 310000China NARI Group Corporation(State Grid Electric Power Research Institute) Nanjing 211106China

In order to reduce the risk of commutation failure(CF)in the AC/DC hybrid power system,the quantitative analysis on CF is required for on-line assessment and optimal *** paper presents an accurate and reliable method to quantify the commutation security based on the trajectory due to the complexity of the high-voltage direct current(HVDC)***,the characteristics of the extinction angle trajectory are analyzed under both commutation success and failure *** commutation security margin index(CSMI)is then proposed for the HVDC ***,a search strategy for parameter limits is put forward based on the sensitivity analysis of CSMI to accelerate the search speed with a guaranteed accuracy level.A modified IEEE 39-bus power system and an actual large-scale power system with 46 generators and 821 buses are utilized to verify the validity and robustness of the proposed index and strategy.

关键词： AC/DC hybrid power system commutation failure(CF) commutation security margin high-voltage direct current(HVDC) security limit

Recent advances in multifunctional shape memory photonic crystals and practical applications

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Nano Research 2024年第1期17卷 79-96页

作者： Yong qi Shufen Zhang State Key Laboratory of Fine Chemicals Frontier Science Center for Smart MaterialsDalian University of TechnologyDalian 116024China

Shape memory photonic crystals(SMPCs)are smart composite materials with changeable structural color integrated by shape memory polymer and photonic *** can produce one or more temporary shapes through nanoscale deformation,memorizing current *** can be recovered to their original shapes or some intermediate states under external stimuli,accompanied by the variation of structural *** porous carriers with built-in sensing properties,SMPCs promoted the interdisciplinary development of nanophotonic technology in materials science,environmental engineering,biomedicine,chemical engineering,and ***,the recent progress on multifunctional SMPCs and practical applications,including traditional and cold programmable SMPCs,is summarized and *** primary concern is shape programming at the nanoscale that has demonstrated numerous attractive functions,including smart sensing,ink-free printing,solvent detection,reprogrammable gradient wetting,and controllable bubble transportation,under variations of the surface *** aims to figure out the nanoscale shape memory effects on structural color conversion and additional performance,inspiring the fabrication of the next generation of ***,perspectives on future research directions and applications are also *** is believed that multifunctional SMPCs are powerful nanophotonic tools for the interdisciplinary development of numerous disciplines in the future.

关键词： photonic crystal shape memory structural color cold programmable shape recovery

A chromosome minimalist view of genome regulation and evolution based on mouse chromosome engineering

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Zoological Research 2022年第6期43卷 949-951页

作者： qi Zhou MOE Laboratory of Biosystems Homeostasis and Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology Life Sciences InstituteZhejiang UniversityHangzhouZhejiang 310058China Center for Reproductive Medicine 2nd Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhouZhejiang 310052China Evolutionary&Organismal Biology Research Center School of MedicineZhejiang UniversityHangzhouZhejiang 310058China

What is the minimum number of chromosomes that a eukaryotic species can tolerate?This question has long fascinated biologists as chromosomal rearrangements are associated with both speciation and various genetic *** a... 详细信息

关键词： evolution Kunming chromosome

New materials and designs for 2D-based infrared photodetectors

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Nano Research 2023年第2期16卷 3074-3103页

作者： Huitian Guo Weihong qi State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi’an 710072China Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing Yantai 264006China

Infrared photodetectors have attracted much attention considering their wide civil and military ***-dimensional(2D)materials offer new opportunities for the development of costless,high-level integration and high-performance infrared *** the advent of a broad investigation of infrared photodetectors based on graphene and transition metal chalcogenides(TMDs)exhibiting unique properties in recent decades,research on the better performance of 2D-based infrared photodetectors has been extended to a larger scale,including explorations of new materials and artificial structure *** this review,after a brief background introduction,some major working mechanisms,including the photovoltaic effect,photoconductive effect,photogating effect,photothermoelectric effect and bolometric effect,are briefly ***,the discussion mainly focuses on the recent progress of three categories of 2D materials beyond graphene and *** transition metal dichalcogenides,black phosphorus and arsenic black phosphorous and 2D ternary compounds are great examples of explorations of mid-wavelength or even long-wavelength 2D infrared ***,four types of rational structure designs,including type-II band alignments,photogating-enhanced designs,surface plasmon designs and ferroelectric-enhanced designs,are discussed to further enhance the performance via diverse mechanisms,which involve the narrower-bandgap-induced interlayer exciton transition,gate modulation by trapped carriers,surface plasmon polaritons and ferroelectric polarization in ***,applications including imaging,flexible devices and on-chip integration for 2D-based infrared photodetectors are ***,a summary of the state-of-the-art research status and personal discussion on the challenges are delivered.

关键词： two-dimensional(2D)materials infrared photodetectors noble transition metal dichalcogenides black phosphorus layered ternary compounds structure designs

Process parameters influence on zone refining and thermodynamics analysis of 1,2-diphenylethane

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Chinese Journal of Chemical Engineering 2022年第2期35卷 338-343页

作者： Yabing qi Jun Li School of Chemistry and Chemical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China School of Chemical Engineering Sichuan UniversityChengdu 610065China

Effective distribution coefficients of 9 impurities in 1,2-diphenylethane have been calculated by directional crystallization under different ambient frozen *** effect of varied zone size,temperature difference between the melt and ambient frozen environment,number of zone on purity of 1,2-diphenylethane have been also investigated during the process of zone *** results indicate that the product purity in the intermediate purified region with varied zone size is higher 0.04%–0.2%than that with constant zone *** product purity increases with temperature difference between the melt and ambient frozen *** appropriate temperature difference is adopted 50°*** product purity in the intermediate region of sample bar with 2 molten zones is higher 0.05%–0.43%than that with 1 molten *** addition,the change of enthalpy and entropy between impurities and 1,2-diphenylethane have been determined.

关键词： 12-Diphenylethane Zone refining Varied zone size Effective distribution coefficient Thermodynamics