检索结果-南通市图书馆

Sliding and damming properties of granular debris with different geometric configurations and grain size distributions

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第3期21卷 932-951页

作者： HE Ligeng TAN Longmeng YANG Xingguo ZHOU Jiawen LIAO Haimei College of Civil Engineering Guizhou UniversityGuiyang 550025China Quality Supervision and Law Enforcement detachment of Guizhou Province Traffic Construction Engineering Guiyang 550081China state Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610065China

Granular debris plays a significant role in determining damming deposit characteristics. An indepth understanding of how variations in grain size distribution(GSD) and geometric configurations impact the behavior of granular debris during the occurrence of granular debris is essential for precise assessment and effective mitigation of landslide hazards in mountainous terrains. This research aims to investigate the impact of GSD and geometric configurations on sliding and damming properties through laboratory experiments. The geometric configurations were categorized into three categories based on the spatial distribution of maximum volume: located at the front(Type Ⅰ), middle(Type Ⅱ), and rear(Type Ⅲ) of the granular debris. Our experimental findings highlight that the sliding and damming processes primarily depend on the interaction among the geometric configuration, grain size, and GSD in granular debris. Different sliding and damming mechanisms across various geometric configurations induce variability in motion parameters and deposition patterns. For Type Ⅰ configurations, the front debris functions as the critical and primary driving component, with energy dissipation primarily occurring through inter-grain interactions. In contrast, Type Ⅱ configurations feature the middle debris as the dominant driving component, experiencing hindrance from the front debris and propulsion from the rear, leading to complex alterations in sliding motion. Here, energy dissipation arises from a combination of inter-grain and grain-substrate interactions. Lastly, in Type Ⅲ configurations, both the middle and rear debris serve as the main driving components, with the rear sliding debris impeded by the front. In this case, energy dissipation predominantly results from grainsubstrate interaction. Moreover, we have quantitatively demonstrated that the inverse grading in damming deposits, where coarse grain moves upward and fine grain moves downward, is primarily caused by grain sortin

关键词： Landslide dam Geometric configuration Energy dissipation Inverse grading Physical experiment

Mechanical behavior and response mechanism of porous metal structures manufactured by laser powder bed fusion under compressive loading

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 737-749页

作者： Xuanming Cai Yang Hou Wei Zhang Zhiqiang Fan Yubo Gao Junyuan Wang Heyang Sun Zhujun Zhang Wenshu Yang School of Aerospace Engineering North University of ChinaTaiyuan 030051China School of Materials Science and Engineering North University of ChinaTaiyuan 030051China School of Astronautics Harbin Institute of TechnologyHarbin 150080China School of Mechanical Engineering North University of ChinaTaiyuan 030051China Shijiazhuang Campus Army Engineering University of PLAShijiazhuang 050003China 65589 Unit 91 detachment Daqing 163411China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150080China

Al Si10Mg porous protective structure often produces different damage forms under compressive loading,and these damage modes affect its protective *** order to well meet the service requirements,there is an urgent need to comprehensively understand the mechanical behavior and response mechanism of AlSi10Mg porous structures under compressive *** this paper,Al Si10Mg porous structures with three kinds of volume fractions are designed and optimized to meet the requirements of high-impact,strong-energy absorption,and lightweight *** mechanical behaviors of AlSi10Mg porous structures,including the stress-strain relationship,structural bearing state,deformation and damage modes,and energy absorption characteristics,were obtained through experimental studies at different loading *** damage pattern of the damage section indicates that AlSi10Mg porous structures have both ductile and brittle mechanical *** simulation studies show that the AlSi10Mg porous structure undergoes shear damage due to relative misalignment along the diagonal cross-section,and the damage location is almost at 45°to the load direction,which is the most direct cause of its structural damage,revealing the damage mechanism of AlSi10Mg porous structures under the compressive *** normalized energy absorption model constructed in the paper well interprets the energy absorption state of Al Si10Mg porous structures and gives the sensitive location of the structures,and the results of this paper provide important references for peers in structural design and optimization.

关键词： AlSi10Mg additive manufacture energy absorption characteristics damage by deformation mechanical behavior

Research on strategies to Promote the Integration of Industrial Chain,Innovation Chain,and Supply Chain in the Beijing-Tianjin-Hebei Region

在线全文

学校读者我要写书评

暂无评论

Proceedings of Business and Economic studies 2024年第4期7卷 166-171页

作者： Chengguo E Ahui Mao Xiuyan Huang Lian Lian Kun Yi Hebei University of Environmental Engineering Qinhuangdao 066102China Qinhuangdao Transportation Comprehensive Administrative Law Enforcement detachment Qinhuangdao 066000China Qinhuangdao Rural Highway Development Center Qinhuangdao 066000China

With the rapid development of international economic integration,industrial competition has gradually evolved from a competition of enterprise capabilities and resources to a game of comprehensive system collaboration capabilities among all participating *** is,the competition in the current international economy has evolved into an interactive and collaborative competition among the“three chains”of industry chain,capital chain,and innovation *** on analyzing the current situation of the integration of the industrial chain,innovation chain,and supply chain,this article deeply analyzes the geographical advantages of the three chains in the Beijing-Tianjin-Hebei *** the perspective of scientific and technological innovation and talent cooperation synergy,it proposes the integration strategy of the three chains in the Beijing-Tianjin-Hebei region.

关键词： Industrial chain Innovation chain Supply chain Beijing-Tianjin-Hebei Spatial distribution

Nonlinear dynamic modeling of a helicopter planetary gear train for carrier plate crack fault diagnosis

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2016年第3期29卷 675-687页

作者： Fan Lei Wang Shaoping Wang Xingjian Han Feng Lyu Huawei School of Automation Science and Electrical Engineering Beihang University 41th detachment People’s Liberation Army Troop 61267

Planetary gear train plays a significant role in a helicopter operation and its health is of great importance for the flight safety of the helicopter. This paper investigates the effects of a planet carrier plate crack on the dynamic characteristics of a planetary gear train, and thus finds an effec- tive method to diagnose crack fault. A dynamic model is developed to analyze the torsional vibra- tion of a planetary gear train with a cracked planet carrier plate. The model takes into consideration nonlinear factors such as the time-varying meshing stiffness, gear backlash and viscous damping. Investigation of the deformation of the cracked carrier plate under static stress is performed in order to simulate the dynamic effects of the planet carrier crack on the angular displacement of car- rier posts. Validation shows good accuracy of the developed dynamic model in predicting dynamic characteristics of a planetary gear train. Fault features extracted from predictions of the model reveal the correspondence between vibration characteristic and the conditions （length and position） of a planet carrier crack clearly.

关键词： Angular shift Carrier plate crack Crack fault diagnosis Helicopter planetary geartrain Nonlinear dynamicsmodeling

Preparation of temperature-controlled salt storage materials and application in ultra-thin friction course

在线全文

学校读者我要写书评

暂无评论

Journal of Traffic and Transportation Engineering(English Edition) 2024年

作者： Yixue Shang Peng Guo Junfeng Gao Yunxia Feng Yuhong Luo Yuanzhao Chen Yang Liu Feng Wang National and Local Joint Engineering Research Center of Transportation and Civil Engineering Materials， Chongqing Jiaotong University School of Civil Engineering and Transportation， North China University of Water Resources and Electric Power Transportation Comprehensive Administrative Law Enforcement detachment，Chizhou Transportation Bureau China Merchants Chongqing Highway Engineering Testing Center Co.，Ltd.

Salt-storage anti-icing ultra-thin friction courses （SAUTFC） are an effective preventive maintenance treatment to improve road performance and ensure the safety of winter pavement traffic. However， the addition of salt storage agents and precipitates decreases the engineering and anti-icing performance. Hence， this study used the temperature-controlled salt-controlled-release deicer （SCD） to prepare and characterize SAUTFC. The microstructure and properties of SCD were investigated. The SAUTFC preparation procedures and content of SCD were determined. Subsequently， the interlayer bonding properties， skid resistance performance， and anti-freeze properties were evaluated. The results indicated that SCD with a glass transition temperature of 0.2 °C can control the precipitation of salts before the winter. The SCD dosing in SAUTFC is 75% of the replacement mineral powder， and interlayer shear strength reaches its maximum when the application rate of the tack coat is 1 kg/m2. The wear resistance of SAUTFC was investigated by accelerated loading tests， which showed that SAUTFC still provides excellent skid resistance after four years. In addition， the SAUTFC accelerates the melting rate of snow and ice and decreases the bonding force between ice and the specimen surface， with excellent anti-freeze durability. Therefore， the application of salt storage materials in ultra-thin friction courses to provide active snow and ice removal on winter pavements is feasible.

关键词：

Fusion of Infrared and Visible Images Based on Infrared Object Extraction

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2021年第2期30卷 339-348页

作者： RONG Chuanzhen LIU Gaohang PING Zhuolin JIA Yongxing YUE Zhenjun XU Guanghui Communications Engineering College Army Engineering University of PLA Qingyang detachment of Armed Police

The ideal fused results of infrared and visible images, should contain the important infrared objects, and preserve the visible textural detail information as much as possible. The fused images are more consistent with human visual perception effect. For this purpose, a novel infrared and visible image fusion framework is proposed. Under the guidance of the model, the source images are decomposed into large-scale edge, small-scale textural detail and coarse-scale base level information. Among which, the large-scale edge information contains the main infrared features, on this basis, the infrared image is further segmented into the object, transition and background regions by OTSU multi-threshold segmentation algorithm. In the end, the fused weights for the decomposed sub-information are determined by the segmented results, so that, the infrared object information can be effectively injected into the fused image, and the important visible textural detail information can be preserved as much as possible in the fused image. Experimental results show that, the proposed method can not only highlight the infrared objects, but also preserve the visual information in the visible image as much as possible. The fused results are superior to the commonly used representative fusion methods, both in subjective perception and objective evaluation.

关键词： Optical, image and video signal processing Sensor fusion Computer vision and image processing techniques Image fusion Image segmentation Gaussian filtering Bilateral filtering Infrared feature extraction

Recovery of bismuth and antimony metals from pressure-leaching slag

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2012年第1期31卷 102-106页

作者： Zhang, Bao Li, Qian Shen, Wenqian Min, Xiaobo School of Metallurgical Science and Engineering Central South University Changsha 410083 China 1st detachment Tianjin Contingent of Chinese People's Armed Police Force Tianjin 300222 China

The leaching behavior of metals from a pressure-leaching slag was investigated using a desulphurization-leaching-hydrolysis process for the recovery of bismuth and *** parameters were studied,including the amount of acid added,temperature,time,addition of NaCl and solid-liquid ratio in the leaching *** experimental results show that the contents of bismuth and antimony are mostly enriched in the process of kerosene *** than 98% Sb and 96% Bi are extracted under the determined *** the process of hydrolysis,the precipitation rates of bismuth and antimony are 97.80% and 94.59%,*** the optimum experimental conditions,the recovery rate of bismuth and antimony can be up to 95.80% and 90.80%,respectively.

关键词： pressure-leaching slag desulphurization hydrolysis precipitation

Leaching process of selenium residue

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2012年第9期19卷 2440-2446页

作者：李倩张宝闵小波申文前 School of Metallurgical Science and Engineering Central South University The First detachment Tianjin Contingent of Ch inese Armed Police Forces

A thermodynamics analysis on the leaching process of selenium residue and discussion on the behaviors of aqueous ionic in the leaching process were carried out. Through thermodynamical calculation, the values of AG and relevant potential expressions were obtained. According to these thermodynamical data, the φ-pH diagrams of Se-H2O system at 298 and 373 K were obtained; Simultaneously, the φ-pH diagrams of SO2-H2O and SO2-Se-H2O systems were drawn at 298 K. With increasing the temperature, the stable regions of HSeO3, SeO2- and SeO2- in the φ-pH diagram of Se-H2O system become gradually large, but the limits of pH in the stable region become gradually small. The stability area of reduction precipitation in the SO2-Se-H2O system was finally determined. The results of oxidization leaching experiments of selenium residue indicate that when the mass ratio of selenium residue to sodium chlorate is 2, the concentration of sulfuric acid is 300 g/L and the residue is agitated for 3 h at leaching temperature of 80 ℃, the leaching rate of selenium could reach 97.76 %. The experimental results conform the calculated results by φ-pH diagram. The selenium reduction precipitation in oxidization-leaching solution was analyzed under the conditions of acidity of 150 g/L, the sodium sulphite concentration of 35 g/L at the reductive temperature of 23 ℃ for 120 min. And this demonstrates the thermodynamics analysis.

关键词： thermodynamics analysis selenium residue Se-H2O system φ-pH diagram SO2-Se-H2O system

Performance of halogen-free flame retardant EVA/MH/LDH composites with nano-LDHs and MH

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2011年第35期56卷 3878-3883页

作者： DING YanYan XU Liang HU GengSheng College of Materials and Environmental Engineering Hangzhou Dianzi University Hangzhou 310018 China Jinhua Fire detachment of Zhejiang Province Jinhua 310014 China

The flammability properties of three series of Ethylene-Vinyl Acetate/Magnesium Hydroxide/Layered Double Hydroxide(EVA/MH/LDH) composites as well as the flame retardance effect between LDH and the conventional flame retardant additive MH are *** addition to acting as an insulating barrier,LDH assists the dispersion of MH particles in the EVA matrix,and promotes the formation of the char residues because of its abundant interlayer hydroxyl *** containing LDH show good flame retardancy in Cone and LOI *** means that the combustion properties of the composites have decreased,which may lessen the fire hazard when this materials are used.

关键词：阻燃复合材料 LDHs 阻燃效果燃烧性能 EVA 层状双金属氢氧化物无卤素纳米