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Recent progress in porous intermetallics:Synthesis mechanism,pore structure,and material properties

Journal of Materials Science & Technology 2021年第15期74卷 89-104页

作者： yao jiang Yuehui He Haiyan Gao State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083China

Intermetallic compounds have the characteristics of long-range ordered structure and combination of metallic and covalent bonds,showing intrinsic brittleness and outstanding performance *** synthesis mechanism,pore structure characterization and material properties of powder metallurgy porous intermetallics are reviewed in this *** with traditional porous materials,porous intermetallics have good thermal impact resistance,machinability,thermal and electrical conductivity similar to metals,as well as good chemical corrosion resistance,rigidity and high-temperature property similar to *** mechanisms of preparation and pore formation of porous intermetallics mainly include four aspects:(1)the physical process based on the interstitial space between the initial particles and its evolution in the subsequent procedures;(2)the chemical combustion process based on the violent reaction between the initial powder components;(3)the reaction kinetics process based on the difference between the diffusion rates of elements;(4)the phase transition process based on the difference between the phase *** characterization parameters to the pore structure description for porous intermetallics include mainly overall porosity,open porosity,permeability,maximum pore size,pore size distribution and tortuosity *** terms of microstructure characterization of porous intermetallics,three-dimensional pore morphology scanning technology has the potential to reveal the internal characteristics of pore *** research on material properties of porous intermetallics mainly focuses on electrochemical catalytic activity,generalized oxidation resistivity at high temperature,resistance against chemical corrosion and mechanical properties,which have obvious advantages over traditional porous *** the field of the development of porous intermetallics,it is expected to expand their applications by further reducing the pore size to the nanoscale

关键词： Intermetallic compound Porous material Preparation mechanism Pore structure Material property

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Running Accuracy Analysis of a 3-RRR Parallel Kinematic Machine Considering the Deformations of the Links

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Chinese Journal of Mechanical Engineering 2014年第5期27卷 890-899页

作者： WANG Liping jiang yao LI Tiemin Department of Mechanical Engineering Tsinghua University

Parallel kinematic machines have drawn considerable attention and have been widely used in some special ***,high precision is still one of the challenges when they are used for advanced machine *** of the main reasons is that the kinematic chains of parallel kinematic machines are composed of elongated links that can easily suffer deformations,especially at high speeds and under heavy loads.A 3-RRR parallel kinematic machine is taken as a study object for investigating its accuracy with the consideration of the deformations of its links during the motion *** on the dynamic model constructed by the Newton-Euler method,all the inertia loads and constraint forces of the links are computed and their deformations are *** the kinematic errors of the machine are derived with the consideration of the deformations of the *** further derivation,the accuracy of the machine is given in a simple explicit expression,which will be helpful to increase the calculating *** accuracy of this machine when following a selected circle path is *** influences of magnitude of the maximum acceleration and external loads on the running accuracy of the machine are *** results show that the external loads will deteriorate the accuracy of the machine tremendously when their direction coincides with the direction of the worst stiffness of the *** proposed method provides a solution for predicting the running accuracy of the parallel kinematic machines and can also be used in their design optimization as well as selection of suitable running parameters.

关键词： parallel kinematic machine dynamic model accuracy deformations

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Estimation of Shallow Landslide Susceptibility Incorporating the Impacts of Vegetation on Slope Stability

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International Journal of Disaster Risk Science 2023年第4期14卷 618-635页

作者： Hu jiang Qiang Zou Bin Zhou yao jiang Junfang Cui Hongkun yao Wentao Zhou Key Laboratory of Mountain Hazards and Earth Surface Process Institute of Mountain Hazards and Environment(IMHE)Chinese Academy of Sciences(CAS)Chengdu 610041China China-Pakistan Joint Research Center on Earth Sciences Islamabad 45320Pakistan University of Chinese Academy of Sciences Beijing 100049China

This study aimed to develop a physical-based approach for predicting the spatial likelihood of shallow landslides at the regional scale in a transition zone with extreme *** landslide susceptibility study in an area with diverse vegetation types as well as distinctive geographic factors(such as steep terrain,fractured rocks,and joints)that dominate the occurrence of shallow landslides is *** article presents a novel methodology for comprehensively assessing shallow landslide susceptibility,taking into account both the positive and negative impacts of *** includes considering the positive efects of vegetation canopy interception and plant root reinforcement,as well as the negative efects of plant gravity loading and preferential fow of root *** approach was applied to simulate the regional-scale shallow landslide susceptibility in the Dadu River Basin,a transition zone with rapidly changing terrain,uplifting from the Sichuan Plain to the Qinghai–Tibet *** research fndings suggest that:(1)The proposed methodology is efective and capable of assessing shallow landslide susceptibility in the study area;(2)the proposed model performs better than the traditional pseudo-static analysis method(TPSA)model,with 9.93%higher accuracy and 5.59%higher area under the curve;and(3)when the ratio of vegetation weight loads to unstable soil mass weight is high,an increase in vegetation biomass tends to be advantageous for slope *** study also mapped the spatial distribution of shallow landslide susceptibility in the study area,which can be used in disaster prevention,mitigation,and risk management.

关键词： Physical-based model Qinghai-Tibet Plateau Shallow landslide Susceptibility analysis Vegetation effect

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Minimally invasive techniques for lateral maxillary sinus floor elevation: small lateral window and one-stage surgery—a 2–5-year retrospective study

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International Journal of Oral Science 2023年第3期15卷 401-410页

作者： Shaojingya Gao yao jiang Yangxue yao Songhang Li Xiaoxiao Cai State Key Laboratory of Oral Diseases&National Center for Stomatology&National Clinical Research Center for Oral Diseases&West China Hospital of Stomatology Sichuan UniversityChengduChina Department of Demography Zhou Enlai School of GovernmentNankai UniversityTianjinChina

This study aimed to introduce a minimally invasive technique for maxillary sinus floor elevation using the lateral approach(lSFE)and to determine the factors that influence the stability of the grafted area in the sinus *** patients(30 implants)treated with lSFE using minimally invasive techniques from 2015 to 2019 were included in the *** aspects of the implant(central,mesial,distal,buccal,and palatal bone heights[BHs])were measured using cone-beam computed tomography(CBCT)before implant surgery,immediately after surgery(T0),6 months after surgery(T1),and at the last follow-up visit(T2).Patients’characteristics were collected.A small bone window(height,(4.40±0.74)mm;length,(6.26±1.03)mm)was *** implant failed during the follow-up period(3.67±1.75)*** of the 30 implants exhibited *** in BH of the five aspects of implants showed strong correlations with each other and BH decreased dramatically before second-stage *** bone height(RBH)did not significantly influence BH changes,whereas smoking status and type of bone graft materials were the potentially influential *** the approximate three-year observation period,lSFE with a minimally invasive technique demonstrated high implant survival rate and limited bone reduction in grafted *** conclusion,lSFE using minimally invasive techniques was a viable treatment *** who were nonsmokers and whose sinus cavity was filled with deproteinized bovine bone mineral(DBBM)had significantly limited bone resorption in grafted area.

关键词： surgery viable floor

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Lie Group Analysis and Invariant Solutions for Nonlinear Time-Fractional Diffusion-Convection Equations

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Communications in Theoretical Physics 2017年第9期67卷 295-300页

作者： Cheng Chen yao-Lin jiang School of Mathematics and Statistics Xi＇an Jiaotong University Xi＇an 710049 China

On the basis of Lie group theory,(1 + N)-dimensional time-fractional partial differential equations are studied and the expression of η_α~0 is given. As applications, two special forms of nonlinear time-fractional diffusionconvection equations are investigated by Lie group analysis method. Then the equations are reduced into fractional ordinary differential equations under group transformations. Therefore, the invariant solutions and some exact solutions are obtained.

关键词： Lie group analysis Riemann-Liouville derivative invariant solution

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Windowing Waveform Relaxation of Initial Value Problems

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Acta Mathematicae Applicatae Sinica 2006年第4期22卷 575-588页

作者： yao-lin jiang Department of Mathematical Sciences Xi'an Jiaotong University Xi'an 710049 China

We present a windowing technique of waveform relaxation for dynamic systems. An effective estimation on window length is derived by an iterative error expression provided here. Relaxation processes can be speeded up if one takes the windowing technique in advance. Numerical experiments are given to further illustrate the theoretical analysis.

关键词： Initial value problems waveform relaxation semigroup solutions windowing technique parallel processing

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Magnetically responsive porous materials for efficient adsorption and desorption processes

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Chinese Journal of Chemical Engineering 2019年第6期27卷 1324-1338页

作者： Peng Tan yao jiang Xiaoqin Liu Linbing Sun State Key Laboratory of Materials-Oriented Chemical Engineering Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)College of Chemical EngineeringNanjing Tech University

Magnetically responsive porous materials possess unique properties in adsorption processes such as magneticinduced separation and heat generation in alternating magnetic fields, which greatly facilitates recycling procedures, favors long-term operation, and improves desorption rate, making conventional adsorption processes highly efficient. With increasing interest in magnetic adsorbents, great progress has been made in designing and understanding of magnetically responsive porous materials varying from monoliths to nanoscale particles used for adsorption including oil uptake, removal of hazardous substances from water, deep desulfurization of fuels, and CO2 capture in the past few years. Therefore, a review summarizing the advanced strategies of synthesizing these magnetically responsive adsorbents and the utilization of their magnetism in practical applications is highly desired. In this review, we give a comprehensive overview of this emerging field, highlighting the strategies of exquisitely incorporating magnetism to porous materials and subtly exploiting their magnetic responsiveness. Further innovations for fabricating or utilizing magnetic adsorbents are expected to be fueled. The potential opportunities and challenges are also discussed.

关键词： Adsorbents Adsorption Desorption Separation Porous materials Magnetic composites

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Analytical Compliance Modeling of Serial Flexure-Based Compliant Mechanism Under Arbitrary Applied Load

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Chinese Journal of Mechanical Engineering 2017年第4期30卷 951-962页

作者： Li-Ping Wang yao jiang Tie-Min Li Institute of Manufacturing Engineering Department of MechanicalTsinghua UniversityBeijing 100084China Beijing Key Laboratory of Precision/Ultra-Precision Manufacturing Equipments and Control Tsinghua UniversityBeijing 100084China Institute of Instrument Science and Technology Department of Precision InstrumentTsinghua UniversityBeijing 100084China

Analytical compliance model is vital to the flexure- based compliant mechanism in its mechanical design and motion control. The matrix is a common and effective approach in the compliance modeling while it is not well developed for the closed-loop serial and parallel compliant mechanisms and is not applicable to the situation when the external loads are applied on the flexure mem- bers. Concise and explicit analytical compliance models of the serial flexure-based compliant mechanisms under arbitrary loads are derived by using the matrix method. An equivalent method is proposed to deal with the situation when the external loads are applied on the flexure mem- bers. The external loads are transformed to concentrated forces applied on the rigid links, which satisfy the equa- tions of static equilibrium and also guarantee that the deformations at the displacement output point remain unchanged. Then the matrix method can be still adopted for the compliance analysis of the compliant mechanism. Finally, several specific examples and an experimental testare given to verify the effectiveness of the compliance models and the force equivalent method. The research enriches the matrix method and provides concise analytical compliance models for the serial compliant mechanism.

关键词： Compliant mechanism Compliancemodeling Matrix method

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Enhancing forest insect outbreak detection by integrating tree-ring and climate variables

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Journal of Forestry Research 2024年第6期35卷 279-293页

作者： yao jiang Zhou Wang Zhongrui Zhang Xiaogang Ding Shaowei jiang jianguo Huang Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems Guangdong Provincial Key Laboratory of Applied BotanySouth China Botanical GardenChinese Academy of SciencesGuangzhou 510650People’s Republic of China University of Chinese Academy of Sciences Beijing 100049People’s Republic of China Ministry of Emergency Management of China National Institute of Natural HazardsBeijing 100085People’s Republic of China MOE Key Laboratory of Biosystems Homeostasis and Protection College of Life SciencesZhejiang UniversityHangzhou 310000People’s Republic of China Guangdong Academy of Forestry Guangzhou 510520People’s Republic of China

Annual tree rings are widely recognized as valuable tools for quantifying and reconstructing historical forest ***,the influence of climate can complicate the detection of disturbance signals,leading to limited accuracy in existing *** this study,we propose a random under-sampling boosting(RUB)classifier that integrates both tree-ring and climate variables to enhance the detection of forest insect *** study focused on 32 sites in Alberta,Canada,which documented insect outbreaks from 1939 to *** thorough feature engineering,model development,and tenfold cross-validation,multiple machine learning(ML)models were *** models used ring width indices(RWIs)and climate variables within an 11-year window as input features,with outbreak and non-outbreak occurrences as the corresponding output *** results reveal that the RUB model consistently demonstrated superior overall performance and stability,with an accuracy of 88.1%,which surpassed that of the other ML *** addition,the relative importance of the feature variables followed the order RWIs>mean maximum temperature(Tmax)from May to July>mean total precipita-tion(Pmean)in July>mean minimum temperature(Tmin)in *** importantly,the dfoliatR(an R package for detecting insect defoliation)and curve intervention detec-tion methods were inferior to the RUB *** findings underscore that integrating tree-ring width and climate vari-ables as predictors in machine learning offers a promising avenue for enhancing the accuracy of detecting forest insect outbreaks.

关键词： Forest disturbance Insect outbreaks Machine learning Tree-ring analysis

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ON CONTRACTION AND SEMI-CONTRACTION FACTORS OF GSOR METHOD FOR AUGMENTED LINEAR SYSTEMS

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Journal of Computational Mathematics 2010年第6期28卷 901-912页

作者： Fang Chen yao-Lin jiang Bing Zheng Department of Mathematical Sciences Xi'an Jiaotong University Xi'an 710049 China School of Science Xi'an University of Post and Telecommunications Xi'an 710121 China Department of Mathematical Sciences Xi ' an Jiaotong University Xi ' an 710049 China School of Mathematics and Statistics Lanzhou University Lanzhou 730000 China

The generalized successive overrelaxation （GSOR） method was presented and studied by Bai, Parlett and Wang [Numer. Math. 102（2005）, pp.1-38] for solving the augmented system of linear equations, and the optimal iteration parameters and the corresponding optimal convergence factor were exactly obtained. In this paper, we further estimate the contraction and the semi-contraction factors of the GSOR method. The motivation of the study is that the convergence speed of an iteration method is actually decided by the contraction factor but not by the spectral radius in finite-step iteration computations. For the nonsingular augmented linear system, under some restrictions we obtain the contraction domain of the parameters involved, which guarantees that the contraction factor of the GSOR method is less than one. For the singular but consistent augmented linear system, we also obtain the semi-contraction domain of the parameters in a similar fashion. Finally, we use two numerical examples to verify the theoretical results and the effectiveness of the GSOR method.

关键词： Contraction and semi-contraction factors, Augmented linear system, GSOR method Convergence.

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