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Preparation of Self-limiting Heating Cables with Excellent Processability, Mechanical Properties and PTC Effect via Thermal and Electrical Treatments

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Chinese Journal of Polymer Science 2024年第4期42卷 511-520页

作者： Tian-Hao Yang Tong wu qiang Fu State Key Laboratory of Polymer Materials Engineering College of Polymer Science and EngineeringSichuan UniversityChengdu610065China State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan UniversityChengdu610065China

Polymer/conductive filler composites have been widely used for the preparation of self-limiting heating cables with the positive temperature coefficient (PTC) effect. The control of conductive filler distribution and network in polymer matrix is the most critical for performance of PTC materials. In order to compensate for the destruction of the filler network structure caused by strong shearing during processing, an excessive conductive filler content is usually added into the polymer matrix, which in turn sacrifices its processability and mechanical properties. In this work, a facile post-treatment of the as-extruded cable, including thermal and electrical treatment to produce high-density polyethylene (HDPE)/carbon black (CB) cable with excellent PTC effect, is developed. It is found for the as-extruded sample, the strong shearing makes the CB particles disperse uniformly in HDPE matrix, and 25 wt% CB is needed for the formation of conductive paths. For the thermal-treated sample, a gradually aggregated CB filler structure is observed, which leads to the improvement of PTC effect and the notable reduction of CB content to 20 wt%. It is very interesting to see that for the sample with combined thermal and electrical treatment, CB particles are agglomerated and oriented along the electric field direction to create substantial conductive paths, which leads to a further decrease of CB content down to 15 wt%. In this way, self-limiting heating cables with excellent processability, mechanical properties and PTC effect have simultaneously been achieved.

关键词： Self-limiting heating cables Positive temperature coefficient Thermal treatment Electrical treatment

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煤层底板突水变权评价中变权区间及调权参数确定方法

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煤炭学报 2016年第9期41卷 2143-2149页

作者：武强李博中国矿业大学(北京)国家煤矿水害防治工程技术研究中心北京100083 贵州大学喀斯特环境与地质灾害防治重点实验室贵州贵阳550000 贵州大学资源与环境工程学院贵州贵阳550000

基于变权理论的煤层底板突水脆弱性评价模型可以解决传统常权脆弱性评价模型中存在的固定权重不能反映突水主控因素指标值内部差异性对评价结果造成的影响。但是利用变权模型对煤层底板突水评价中变权区间阈值及调权参数的确定目前尚没... 详细信息

基于变权理论的煤层底板突水脆弱性评价模型可以解决传统常权脆弱性评价模型中存在的固定权重不能反映突水主控因素指标值内部差异性对评价结果造成的影响。但是利用变权模型对煤层底板突水评价中变权区间阈值及调权参数的确定目前尚没有统一的分析确定方法,变权区间和调权参数决定了变权模型对研究区主控因素的哪些指标值采取何种幅度的权重调整。针对这两个亟待解决的问题,根据煤层底板突水各主控因素指标值在空间分布上存在差异,但也具有一定的相似性的特征,利用聚类分析方法对各主控因素变权区间阈值进行了确定,同时也对变权评价模型中的调权参数确定探索性提出一种能够满足决策者决策偏好的可行性方法。在此基础上以山东省兴隆庄矿为例进行求解说明和效果验证。

关键词：变权理论底板突水脆弱性评价变权区间阈值调权参数

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Enhanced nitrate removal from groundwater using a conductive spacer in flow-electrode capacitive deionization

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Chinese Chemical Letters 2024年第8期35卷 379-382页

作者： Hongjie Guo qiang Wei Yangyang wu Wei Qiu Hongliang li Changyong Zhang College of Mining Engineering Taiyuan University of TechnologyTaiyuan 030024China CAS Key Laboratory of Urban Pollutant Conversion Department of Environmental Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsUniversity of Science and Technology of ChinaHefei 230026China

Flow-electrode capacitive deionization(FCDI)represents a promising approach for ion separation from aqueous ***,the optimization of spacer,particularly for nitrate-contaminated groundwa-ter systems,has often been *** research comprehensively investigates the influence of using a conductive(carbon cloth,CC)spacer on nitrate removal performance within FCDI system,comparing it to a non-conductive(nylon net,NN)*** both CC and NN FCDI systems,it is unsurprisingly that nitrate removal efficiency improved notably with the increasing current density and hydraulic retention time(HRT).Interestingly,the specific energy consumption(SEC)for nitrate removal did not show obvious fluctuations when the current density and HRT varied in both *** the auspiciously optimized process parameters,CC-FCDI attained a 20%superior nitrate removal efficiency relative to NN-FCDI,ac-companied by a notably diminished SEC for CC-FCDI,registering at a mere 28%of *** great improvement can be primarily attributed to the decrement in FCDI internal resistance after using con-ductive spacer,which further confirmed by electrochemical tests such as linear sweep voltammetry(LSV)and electrochemical impedance spectroscopy(EIS).Upon prolonged continuous nitrate removal at the optimized conditions,the CC-FCDI system achieved a consistent 90%nitrate removal efficiency with a low SEC of 2.7-7.8 kWh/kg NO_(3)-N,underscoring its steady ***,this study highlights the pivotal importance of careful spacer design and optimization in realizing energy-efficient groundwater treatment via FCDI.

关键词： Flow-electrode capacitive deionization Carbon cloth Nitrate Underground water Ions transport

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Advances in ice avalanches on the Tibetan Plateau

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Journal of Mountain Science 2024年第6期21卷 1814-1829页

作者： TANG Minggao li Guang ZHAO Huanle XU qiang wu Guangjian YANG Wei GUO Daojing State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China College of Environment and Civil Engineering Chengdu University of TechnologyChengdu 610059China Institute of Tibetan Plateau Research Chinese Academy of SciencesBeijing 100101China

As some of the greatest natural disasters in the cryosphere,ice avalanches(IAs)seriously threaten lives and cause catastrophic damage to the resource environment,but a comprehensive overview of the state of knowledge on IAs remains *** summarized 63 IAs on the Tibetan Plateau(TP)since the 20th century,of which,over 20 IAs occurred after the 21st *** distributions of IAs are mainly concentrated in the southeastern and northwestern TP,and the occurrence time of IAs is mostly concentrated from July to *** highlight recent advances in mechanical properties and genetic mechanisms of IAs and emphasize that temperature,rainfall,and seismicity are the inducing *** failure modes of IAs are summarized into 6 categories by examples:slip pulling type,slip toppling type,slip breaking type,water level collapse type,cave roof collapse type,and wedge failure ***,we deliver recommendations concerning the risk assessment and prediction of *** results provide important scientific value for addressing climate change and resisting glacier-related hazards.

关键词： Ice avalanche Global warming Genetic mechanism Risk assessment Tibetan Plateau

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Combined blasting for protection of gob-side roadway with thick and hard roof

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3165-3180页

作者： qiang Fu Jun Yang Yubing Gao Changjiang li Hongxu Song Yuxuan liu Xing wu State Key Laboratory for Tunnel Engineering China University of Mining and Technology(Beijing)Beijing100083China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing100083China

The deformation control of surrounding rock in gobside roadway with thick and hard roof poses a significant challenge to the safety and efficiency of coal *** address this issue,a novel approach combining directional and non-directional blasting techniques,known as combined blasting,was *** study focuses on the experimental investigation of the proposed method in the 122108 working face in Caojiatan Coal Mine as the engineering *** initial phase of the study involves physical model experiments to reveal the underlying mechanisms of combined blasting for protecting gob-side roadway with thick and hard *** results demonstrate that this approach effectively accelerates the collapse of thick and hard roofs,enhances the fragmentation and expansion coefficient of gangue,facilitates the filling of the goaf with gangue,and provides support to the overlying strata,thus reducing the subsidence of the overlying strata above the ***,the method involves cutting the main roof into shorter beams to decrease the stress and disrupt stress transmission *** numerical simulations were conducted to corroborate the findings of the physical model experiments,thus validating the accuracy of the experimental ***,field engineering experiments were performed,affirming the efficacy of the combined blasting method in mitigating the deformation of surrounding rock and achieving the desired protection of the gob-side roadway.

关键词： Thick and hard roof Surrounding rock control Combined blasting Fragmentation and expansion support stress relief

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Deformation Characteristics of Hydrate-Bearing Sediments

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Journal of Ocean University of China 2024年第1期23卷 149-156页

作者： DONG lin li Yanlong ZHANG Yajuan HU Gaowei liAO Hualin CHEN qiang wu Nengyou Key Laboratory of Gas Hydrate Ministry of Natural ResourcesQingdao Institute of Marine GeologyQingdao 266237China Laboratory for Marine Mineral Resources Laoshan LaboratoryQingdao 266237China College of Oceanography Hohai UniversityNanjing 210098China College of Petroleum Engineering China University of Petroleum(East China)Qingdao 266555China

The safe and efficient development of natural gas hydrate requires a deep understanding of the deformation behaviors of *** this study,a series of triaxial shearing tests are carried out to investigate the deformation properties of hydrate-bearing *** of volumetric and lateral strains versus hydrate saturation are analyzed *** indicate that the sediments with high hydrate saturation show dilative behaviors,which lead to strain-softening characteristics during *** volumetric strain curves have a tendency to transform gradually from dilatation to compression with the increase in effective confining *** easy prediction model is proposed to describe the relationship between volumetric and axial *** model coefficientβis the key dominating factor for the shape of volumetric strain curves and can be determined by the hydrate saturation and stress ***,a modified model is established for the calculation of lateral *** corresponding determination method is provided for the easy estimation of model coefficients for medium sand sediments containing *** study provides a theoretical and experimental reference for deformation estimation in natural gas hydrate development.

关键词： gas hydrate deformation characteristics volumetric strain lateral strain prediction model

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Evaluating the necessity of autumn irrigation on salinized soil by considering changes in soil physicochemical properties

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Pedosphere 2024年第4期34卷 837-842页

作者： Hang ZHAO Jingwei wu Changsen li Yawen liU Rui ZHANG qiang ZHAO State Key Laboratory of Water Resources Engineering and Management Wuhan UniversityWuhan 430072China

Dear Editor,Soil salinization is one of the main forms of global soil degradation,which seriously threatens food security production (liu et al.,2022).Proper irrigation is the main management measure to control soil salinization (Aragüés et al.,2015;Machado and Serralheiro,2017).For example,in Hetao Irrigation District in Inner Mongolia of northwestern China,the effects of irrigation,seasonal freezing-thawing,and evaporation have led to serious soil salinization *** the 1980s,autumn irrigation (AI) has typically been implemented widely in Hetao Irrigation District before soil freezing (li et al.,2010;Lu et al.,2019),to leach the salts accumulated on the surface and maintain sufficient soil moisture to create a suitable environment for the next spring sowing.

关键词： soil freezing irrigation

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An improved elastoplastic model for rocks and application to cyclic loading and unloading triaxial compression tests

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Acta Mechanica Sinica 2024年第8期40卷 179-193页

作者： Qiuxin Gu qiang Zhang Yapeng li Peinan wu Guilei Han State Key Laboratory for Geomechanics and Deep Underground Engineering School of Mechanics and Civil EngineeringChina University of Mining and TechnologyXuzhou221116China North China Engineering Investigation Institute Shijiazhuang050021China

The recoverable strain of rock is completely classified as elastic strain in the conventional elastic-plastic theory,which often results in poor agreement between theoretical and experimental *** work proposes an improved elastoplastic model of rock materials considering the evolutions of crack deformation and elastic modulus to better characterize the nonlinear mechanical behavior of rock in the post-peak *** this model,the recoverable strain is assumed to be a combination of elastic and crack strain,and the constitutive relationship between crack strain and rock stress is *** on the proposed assumption,the evolutions of the mechanical parameters including strength parameters,elastic,plastic,and crack deformation parameters versus the plastic strain and confining stress were *** developed elastoplastic model was validated by comparing the theoretical values with the results of the triaxial cyclic loading and unloading *** theoretical calculation results show a good agreement with the laboratory test,which indicates that the improved elastoplastic model can effectively reflect the nonlinear mechanical behavior of the rock *** research results are expected to provide a valuable reference for further understanding the evolution of rock crack deformation.

关键词： Crack strain Elastic modulus deterioration Novel elastoplastic model Model validation

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Brain Cognition Mechanism-Inspired Hierarchical Navigation Method for Mobile Robots

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Journal of Bionic Engineering 2024年第2期21卷 852-865页

作者： qiang Zou Chengdong wu Ming Cong Dong liu Faculty of Robot Science and Engineering Northeastern UniversityShenyang110819China School of Mechanical Engineering Dalian University of TechnologyDalian116024China

Autonomous navigation is a fundamental problem in *** methods generally build point cloud map or dense feature map in perceptual space;due to lack of cognition and memory formation mechanism,traditional methods exist poor robustness and low cognitive *** a new navigation technology that draws inspiration from mammal’s navigation,bionic navigation method can map perceptual information into cognitive space,and have strong autonomy and environment *** improve the robot’s autonomous navigation ability,this paper proposes a cognitive map-based hierarchical navigation ***,the mammals’navigation-related grid cells and head direction cells are modeled to provide the robots with location *** then a global path planning strategy based on cognitive map is proposed,which can anticipate one preferred global path to the target with high efficiency and short ***,a hierarchical motion controlling method is proposed,with which the target navigation can be divided into several sub-target navigation,and the mobile robot can reach to these sub-targets with high confidence ***,some experiments are implemented,the results show that the proposed path planning method can avoid passing through obstacles and obtain one preferred global path to the target with high efficiency,and the time cost does not increase extremely with the increase of experience nodes *** motion controlling results show that the mobile robot can arrive at the target successfully only depending on its self-motion information,which is an effective attempt and reflects strong bionic properties.

关键词： Bionic navigation Spatial localization cells Global path planning Hierarchical motion controlling

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The Sequential Pricing of Ride-Hailing System with Rental Service in the Context of Fleet Electrification

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Journal of Systems Science and Systems Engineering 2024年第1期33卷 77-105页

作者： Yaoyao Ku Peng wu qiang Ren Yiqing Wang Business School Sichuan UniversityChengdu610065China

Surging demand and reduced capacity in the ride-hailing industry have prompted numerous ride-hailing platforms to build their own car-rental services catering to drivers who do not possess private vehicles. However, the trade-off between the ride-hailing service and the car-rental service is an important issue that is still unclear in theory. Moreover, ride-hailing platforms are transitioning towards all-electric fleets in the context of Carbon Neutrality goals and government regulations. This paper considers a ride-hailing system comprising a monopolist ride-hailing platform, an electric vehicle (EV) rental firm, and a gasoline vehicle (GV) rental firm. Furthermore, we build a stylized model to study the sequential pricing of the system. The equilibrium outcomes show the significant impact of the ride-hailing platform’s decision to continue or withdraw offering EV rental services on EV and GV drivers’ net earnings, rental prices, and wages. The ride-hailing platform providing EV rental services increases EV drivers’ net earnings but decreases the GV driver wages and rental prices. However, the EV rental service offered by the ride-hailing platform does not necessarily lead to an increased total profit for the system. The improved profitability of the system by the ride-hailing platform providing EV rental services is contingent upon lower rider prices and higher fuel costs. The ride-hailing platform’s EV rental services provision also effectively fosters the ride-hailing fleet’s electrification. Furthermore, as the number of riders increases, the ride-hailing platform should reduce the commission rate for EV drivers to maintain competitiveness and profitability.

关键词： Ride-hailing system car rental fleet electrification sequential pricing differential wage scheme

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