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Effect of icosahedral phase formation on the stress corrosion cracking(SCC)behaviors of the as-cast Mg-8%Li(in wt.%)based alloys

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Journal of Magnesium and Alloys 2024年第1期12卷 225-236页

作者： Shuo Wang Daokui Xu Dongliang Wang zhiqiang zhang Baojie Wang Key Lab of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang110819China Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China Engineering Research Center of Advanced Materials Preparing Technology Ministry of EducationNortheastern UniversityShenyang110819China School of Environmental and Chemical Engineering Shenyang Ligong UniversityShenyang110159China Binzhou Institute of Technology BinzhouShandong Province256606China Shandong Key Laboratory of Advanced Aluminium Materials and Technology BinzhouShandong Province256606China

Through exploring the stress corrosion cracking(SCC)behaviors of the as-cast Mg-8%Li and Mg-8%Li-6%Zn-1.2%Y alloys in a 0.1 M NaCl solution,it revealed that the SCC susceptibility index(I_(SCC))of the Mg-8%Li alloy was 47%,whilst the I_(SCC)of the Mg-8%Li-6%Zn-1.2%Y alloy was 68%.Surface,cross-sectional and fractography observations indicated that for the Mg-8%Li alloy,theα-Mg/β-Li interfaces acted as the preferential crack initiation sites and propagation paths during the SCC process.With regard to the Mg-8%Li-6%Zn-1.2%Y alloy,the crack initiation sites included the I-phase and the interfaces of I-phase/β-Li andα-Mg/β-Li,and the preferential propagation paths were the I-phase/β-Li andα-Mg/β-Li interfaces.Moreover,the SCC of the two alloys was concerned with hydrogen embrittlement(HE)mechanism.

关键词： Magnesium-lithium alloy Stress corrosion cracking I-phase Fracture analysis

黄河流域生态保护迈向高质量发展的特征——植被绿度、生产力和降水利用效率的差异性变化

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Engineering 2024年第3期34卷 109-119页

作者： Yang Yu Ting Hua Liding Chen zhiqiang zhang Paulo Pereira Jixian National Forest Ecosystem Observation and Research Station National Ecosystem Research Network of China(CNERN)School of Soil and Water ConservationBeijing Forestry UniversityBeijing 100083China School of Soil and Water Conservation Beijing Forestry UniversityBeijing 100083China State Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Institute of Land Surface System and Sustainable Development Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Environmental Management Laboratory Mykolas Romeris UniversityVilnius 08303Lithuania

Globally,vegetation has been changing dramatically.The vegetation-water dynamic is key to understanding ecosystem structure and functioning in water-limited ecosystems.Continual satellite monitoring has detected global vegetation greening.However,a vegetation greenness increase does not mean that ecosystem functions increase.The intricate interplays resulting from the relationships between vegetation and precipitation must be more adequately comprehended.In this study,satellite data,for example,leaf area index(LAI),net primary production(NPP),and rainfall use efficiency(RUE),were used to quantify vegetation dynamics and their relationship with rainfall in different reaches of the Yellow River Basin(YRB).A sequential regression method was used to detect trends of NPP sensitivity to rainfall.The results showed that 34.53%of the YRB exhibited a significant greening trend since 2000.Among them,20.54%,53.37%,and 16.73%of upper,middle,and lower reach areas showed a significant positive trend,respectively.NPP showed a similar trend to LAI in the YRB upper,middle,and lower reaches.A notable difference was noted in the distributions and trends of RUE across the upper,middle,and lower reaches.Moreover,there were significant trends in vegetation-rainfall sensitivity in 16.86%of the YRB’s middle reaches—14.08%showed negative trends and 2.78%positive trends.A total of 8.41%of the YRB exhibited a marked increase in LAI,NPP,and RUE.Subsequently,strategic locations reliant on the correlation between vegetation and rainfall were identified and designated for restoration planning purposes to propose future ecological restoration efforts.Our analysis indicates that the middle reach of the YRB exhibited the most significant variation in vegetation greenness and productivity.The present study underscores the significance of examining the correlation between vegetation and rainfall within the context of the high-quality development strategy of the YRB.The outcomes of our analysis and the proposed ecological restoration framework can p

关键词： Vegetation greenness Vegetation productivity Rainfall use efficiency Sensitivity Yellow River Basin

A Review on Flow Boiling of the Fluid with Lower Boiling Point in Micro-Channels

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Journal of Thermal Science 2024年第1期33卷 1-17页

作者： zhang zhiqiang JIA Li DANG Chao Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China

With the advancement of micro machining technology,the high-heat-flux removal from miniature electronic devices and components has become an attractive topic.Flow boiling in micro-channels is an optimal form of heat transfer and has been widely employed in high-heat-flux cooling applications.This comprehensively-reviewed article focused on the available recent literatures of experimental investigation regarding the flow boiling heat transfer and unstable behaviors of the fluid with lower boiling point in micro-channels.The thermal-fluid characteristics and potential heat transfer mechanisms of low-boiling-point fluids flow boiling in different narrow passages were summarized and discussed.The literatures regarding the pressure drop and occurrence of the unstable phenomena existing in two-phase flow boiling process were also discussed.The emphasis was given to the heat transfer enhancement methods as well as instability elimination,and various methods such as modification of surface and channel flow geometries were considered.Some future researches in the field of micro-scale flow boiling were suggested.

关键词： flow boiling lower boiling point fluids mini/micro-channels instabilities enhancement suppression

Influence of Kerr Effect on Second-Order Nonlinearity Induced Transparency

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Wuhan University Journal of Natural Sciences 2024年第1期29卷 67-73页

作者： zhang zhiqiang ZHOU Yanhui College of Architectural Engineering Zhengzhou Business UniversityZhengzhou 451200HenanChina Quantum Information Research Center Shangrao Normal UniversityShangrao 334001JiangxiChina

We theoretically study the effect of Kerr effect on the second-order nonlinearity induced transparency in a double-resonant optical cavity system.We show that in the presence of the Kerr effect,as the strength of the Kerr effect increases,the absorption curve exhibits an asymmetric-symmetric-asymmetric transition,and the zero absorption point shifts with the increase of the Kerr effect.Furthermore,by changing the strength of the Kerr effect,we can control the width of the transparent window,and the position of the zero-absorption point and meanwhile change the left and right width of the absorption peak.The asymmetry absorption curve can be employed to improve the quality factor of the cavity when the frequency detuning is tuned to be around the right peak.The simple dependence of the zeroabsorption point on the strength of Kerr effect suggests that the strength of Kerr effect can be measured by measuring the position of the zero-absorption point in a possible application.

关键词： Kerr effect second-order nonlinearity induced transparency nonlinear optics quantum optics

Origin of tradeoff between movement velocity and attachment duration of kinesin motor on a microtubule

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Chinese Physics B 2024年第2期33卷 557-566页

作者：刘玉颖张志强 Department of Physics College of ScienceChina Agricultural UniversityBeijing 100083China Basic Ministry Space Engineering UniversityBeijing 101416China

Kinesin-1 motor protein is a homodimer containing two identical motor domains connected by a common long coiledcoil stalk via two flexible neck linkers. The motor can step on a microtubule with a velocity of about 1 μm·s-1and an attachment duration of about 1 s under physiological conditions. The available experimental data indicate a tradeoff between velocity and attachment duration under various experimental conditions, such as variation of the solution temperature,variation of the strain between the two motor domains, and so on. However, the underlying mechanism of the tradeoff is unknown. Here, the mechanism is explained by a theoretical study of the dynamics of the motor under various experimental conditions, reproducing quantitatively the available experimental data and providing additional predictions. How the various experimental conditions lead to different decreasing rates of attachment duration versus velocity is also explained.

关键词： motor protein velocity detachment time processivity

Effect of layered joints on rockburst in deep tunnels

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International Journal of Coal Science & Technology 2022年第2期9卷 70-90页

作者： Mingming He Jinrui Zhao Bianyuan Deng zhiqiang zhang State Key Laboratory of Eco-Hydraulics in Northwest Arid Region Xi’an University of TechnologyXi’an 710048China Shaanxi Key Laboratory of Loess Mechanics and Engineering Xi’an University of TechnologyXi’an 710048China YCIH Foundation Engineering Co. Ltd.Kunming 657200China

The existence of joints in the surrounding rock mass has a considerable efect on tunnel rockbursts.Herein,we studied the efect of layered joints with diferent inclination angles and spacings on rockburst in deep tunnels and investigated the failure area,deformation process of the surrounding rock mass,stress change inside the surrounding rock mass,velocity of the failed rock,and the kinetic energy of the failure.The failure type of the surrounding rock mass can thus be determined.The results showed that the intensity of rockburst increases as rock quality designation(RQD)decreases,while the deformation rate of the surrounding rock mass frst increases and then decreases.The deformation rate exhibits a turning point between RQD=50 and 70,below which the deformation rate of the surrounding rock mass gradually decreases,ultimately ceasing to be a rockburst.Rockburst always occurs perpendicular to the direction of the joint.Whenσ_(x)=σ_(y),as the joint inclination angle changes from 45°to 90°,the intensity of a rockburst frst decreases(from 45°to 60°),and then increases(from 60°to 90°).When combined with the evolution law of stress and strain energy,the rockburst process can be divided into four stages.

关键词： Rockburst Jointed rock mass Numerical simulation Deep tunnel

Determination of the constant m_(i) in the Hoek-Brown criterion of rock based on drilling parameters

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International Journal of Mining Science and Technology 2022年第4期32卷 747-759页

作者： Haoteng Wang Mingming He zhiqiang zhang Jiwei Zhu State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi’an University of TechnologyXi’an 710048China Shaanxi Key Laboratory of Loess Mechanics and Engineering Xi’an University of TechnologyXi’an 710048China Research Center of Eco-hydraulics and Sustainable Development The New Style Think Tank of Shaanxi UniversitiesXi’an 710048China

The constant m_(i) in the Hoek-Brown(H-B) criterion is a fundamental parameter required for determining the compressive strength of rock. In this paper, drilling parameters provide a new basis for determining the constant mi. An analytical relationship between the drilling parameters and constant miis established in consideration of the contact response between the drilling bit and the cut rock in the crushed zone.New models are developed to predict the triaxial compressive strength(TCS), internal friction angle φand cohesion c of rock. Drilling tests are carried out on 6 rock types to study the correlation between φ and m_(i). A comparison between the predicted values of rock mechanical properties and the measured values from the laboratory is performed to verify the accuracy of the proposed model(yielding an error less than 10%). The TCSs and constant m_(i) values of fifteen rocks are cited to validate the accuracy of the proposed model. The result shows that the proposed model predicts the TCS and constant m_(i) within a maximum error of 20%. The method can be conveniently applied to the rock mechanical properties.

关键词： Constant miin the H-B criterion Analytical model Friction angle Drilling parameters Triaxial compressive strength

Optimized Design of H-Type Vertical Axis Wind Airfoil at Multiple Angles of Attack

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Fluid Dynamics & Materials Processing 2023年第10期19卷 2661-2679页

作者： Chunyan zhang Shuaishuai Wang Yinhu Qiao zhiqiang zhang School of Mechanical Engineering Anhui Science and Technology UniversityFengyang233100China School of Mechanical Engineering Anhui Polytechnic UniversityWuhu241000China

Numerical simulations are conducted to improve the energy acquisition efﬁciency of H-type vertical axis wind turbines through the optimization of the related blade airfoil aerodynamic performance.The Bézier curve is initi-ally used toﬁt the curve proﬁle of a NACA2412 airfoil,and the moving asymptote algorithm is then exploited to optimize the design of the considered H-type vertical-axis wind-turbine blade airfoil for a certain attack angle.The results show that the maximum lift coefﬁcient of the optimized airfoil is 8.33%higher than that of the original airfoil.The maximum lift-to-drag ratio of the optimized airfoil exceeds the maximum lift-to-drag ratio of the ori-ginal airfoil by 11.22%.Moreover,the power coefﬁcient is increased by 12.19%and the torque coefﬁcient of the wind turbine is signiﬁcantly improved.

关键词： H-type vertical axis wind turbine Bézier curves moving asymptote algorithm airfoil optimization

New method for efficient control of hydrogen sulfide and methane in gravity sewers:Combination of NaOH and nitrite

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Frontiers of Environmental Science & Engineering 2022年第6期16卷 95-108页

作者： Zicong Zhao Jing Yang Zigeng zhang Sheping Wang zhiqiang zhang Jinsuo Lu School of Environmental and Municipal Engineering Xi’an University of Architecture and TechnologyXi’an 710055China Xi’an Municipal Engineering Design&Research Institute Co.Ltd. Xi’an 710000China Key Laboratory of Northwest Water Resources Environment and Ecology(Ministry of Education)Xi’an University of Architecture and TechnologyXi’an 710055China Key Laboratory of Environmental Engineering Xi’an University of Architecture and TechnologyXi’an 710055China

An innovative treatment method by the combination of NaOH and nitrite is proposed for controlling hydrogen sulfide and methane in gravity sewers and overcome the drawbacks of the conventional single chemical treatment.Four reactors simulating gravity sewers were set up to assess the effectiveness of the proposed method.Findings demonstrated hydrogen sulfide and methane reductions of about 96.01%and 91.49%,respectively,by the combined addition of NaOH and nitrite.The consumption of NaNO_(2) decreased by 42.90%,and the consumption rate of NaOH also showed a downward trend.Compared with a single application of NaNO_(2),the C/N ratio of wastewater was increased to about 0.61 mg COD/mg N.The greenhouse effect of intermediate N2O and residual methane was about 48.80 gCO_(2)/m^(3),which is far lower than that of methane without control(260 gCO_(2)/m^(3)).Biofilm was destroyed to prevent it from entering the sewage by the chemical additives,which reduced the biomass and inhibited the recovery of biofilm activity to prolong the control time.The sulfide production rate and sulfate reduction rate were reduced by 92.32%and 85.28%,respectively.Compared with conventional control methods,the cost of this new method was only 3.92×10^(−3)$/m^(3),which is potentially a cost-effective strategy for sulfide and methane control in gravity sewers.

关键词： Sewer corrosion Sulfide control Combination treatment NaOH Nitrite