检索结果-南通市图书馆

基于无线电磁传输的防冲钻孔机器人钻进轨迹随钻测量方法

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

煤炭科学技术 2024年第9期52卷 220-237页

作者：王忠宾司垒顾进恒魏东戴剑博辛德忠张修峰陈航邢飞中国矿业大学机电工程学院中国矿业大学智能采矿装备技术全国重点实验室中煤科工集团重庆研究院有限公司山东能源集团有限公司

防冲钻孔机器人是高地应力矿井实现无人化卸压的必要装备，研发可靠的钻进轨迹随钻测量系统是保障钻孔卸压效果的重要措施。为此，在分析钻进轨迹算随钻测量基本原理的基础上，研制了基于无线电磁传输技术的钻进轨迹随钻测量钻杆；分析... 详细信息

防冲钻孔机器人是高地应力矿井实现无人化卸压的必要装备，研发可靠的钻进轨迹随钻测量系统是保障钻孔卸压效果的重要措施。为此，在分析钻进轨迹算随钻测量基本原理的基础上，研制了基于无线电磁传输技术的钻进轨迹随钻测量钻杆；分析了不同电磁信号调制方式的频谱效益和抗噪声性能，设计了钻杆姿态信号的频移键控（FSK）调制和解调流程，进而开发了先放大后滤波的微弱信号调理系统，设计了相应的功能电路，并基于Multisim软件对其进行了测试，各电路模块满足设计要求。对比分析了5种轨迹解算算法的精度和执行效率，选择了均角全距法进行钻进轨迹解算，研究了基于小波滤波的惯性测量单元测量数据振动误差处理方法，验证了小波滤波算法对于提高姿态角解算精度的有效性。提出了基于拉线位移传感器与机器人动作标志位的钻进深度测量方法，并开展了地面试验与井下试验。试验结果表明：所设计的微弱信号调理系统可以实现煤矿井下微弱信号的接收与处理，基于拉线位移传感器与机器人动作标志位的钻进深度测量方法可以提高钻进轨迹的拟合精度。

关键词：防冲钻孔机器人随钻测量无线电磁传输钻进轨迹解算微弱信号调理

同方期刊数据库

Spatial distribution model of the filling and diffusion pressure of synchronous grouting in a quasi-rectangular shield and its experimental verification

在线全文

学校读者我要写书评

暂无评论

Underground Space 2021年第6期6卷 650-664页

作者： Jun Liu Peinan Li Lai Shi Jie Fan Xiaoyong Kou dezhong Huang College of Urban Railway Transportation Shanghai University of Engineering ScienceShanghai 201620China College of Environmental Science and Engineering Donghua UniversityShanghai 201620China China Railway Siyuan Survey and Design Group Co. LtdWuhanHubei 430063China Shanghai Tunnel Engineering Co. LtdShanghai 200032China

Considering that the particular geometric shape of a quasi-rectangular shield,the grout flowing law and its motion process are more complicated than those of a conventional circular *** interpret the grouting mechanical ehaviour in the special-shape shield tail void,the filling and diffusion mechanism of synchronous grouting was *** grout flowing is separated into two independent motion processes,which contains a circumferential filling and a longitudinal *** theoretical model of the grout pressure spatial distribution was derived based on the principle of fluid ***,the pressure distributions in the two directions were obtained using a case study and compared with the field measured data to verify the validation of the *** the overall spatial pattern of grout pressure distribution on the tunnel profile show a change trend dominated by the self-weight effect mostly,its local fluctuation characteristics is very abnormal relative to that of a circular shield ***,the important factors in the model were analysed,including the grout material parameters,the grouting construction parameters,and some geometry *** results show that the pressure loss along this way is positively correlated with the grout flow velocity and is sensitive to the shear yield stress of the *** pressure loss along the circumferential direction is the most sensitive to the thickness of the ring cake,and the value range suitable for the model should be 0.02-0.03 *** pressure loss along the longitudinal diffusion direction is the most sensitive to the size of the tail *** research results can provide a theoretical basis for the control of special-shape shield construction.

关键词： Tunnel engineering Quasi-rectangular shield Synchronous grouting Filling and diffusion Pressure spatial distribution model Experimental verification

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

稀有矿物方硼石人工合成与功能特性研究进展

矿物学报 2024年第1期44卷 33-42页

作者：汪强强孙瑞锦武岳彤郭杰森陈飞马宇欣孟德忠赵长春中国地质大学(北京)数理学院北京100083

方硼石是一个罕见的极性矿物家族,大量针对方硼石热释电性的研究表明,方硼石在未进行任何改性的情况下就具有接近PZT等材料的热释电性能,而其结构并不是传统的钙钛矿构型,且不含有任何毒性元素,它作为一种热释电材料极具研究与应用价值... 详细信息

方硼石是一个罕见的极性矿物家族,大量针对方硼石热释电性的研究表明,方硼石在未进行任何改性的情况下就具有接近PZT等材料的热释电性能,而其结构并不是传统的钙钛矿构型,且不含有任何毒性元素,它作为一种热释电材料极具研究与应用价值。遗憾的是受限于材料质量等原因,至今方硼石的热释电机理与共性构效关系并未被阐明,因此针对方硼石的系统性改性研究还未深入开展,其热释电应用潜力也未被很好地开发。基于以上科学问题,本文综述了方硼石矿物晶体材料的人工合成方法和介电、热释电、铁电、铁磁、铁弹以及非线性光学等性质的研究进展,以期为后续进一步合成方硼石单晶、研究其本征物性以及性能调控提供重要参考。

关键词：方硼石硼酸盐矿物人工合成性能研究

Stochastic fluctuations of permittivity coupling regulate seizure dynamics in partial epilepsy

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2017年第7期60卷 995-1002页

作者： GUO DaQing XIA Chuan WU ShengDun ZHANG TianJiao ZHANG YangSong XIA Yang YAO dezhong Key Laboratory for Neurolnformation of Ministry of Education School of Life Science and TechnologyUniversity of Electronic Science and Technology of ChinaChengdu 610054China Center for Information in Medicine University of Electronic Science and Technology of ChinaChengdu 610054China School of Computer Science and Technology Southwest University of Science and TechnologyMianyang 621002China

Partial epilepsy is characterized by recurrent seizures that arise from a localized pathological brain region. During the onset of partial epilepsy, the seizure evolution commonly exhibits typical timescale separation phenomenon. This timescale separation behavior can be mimicked by a paradigmatic model termed as Epileptor, which consists of coupled fast-slow neural populations via a permittivity variable. By incorporating permittivity noise into the Epileptor model, we show here that stochastic fluctuations of permittivity coupling participate in the modulation of seizure dynamics in partial epilepsy. In particular, introducing a certain level of permittivity noise can make the model produce more comparable seizure-like events that capture the temporal variability in realistic partial seizures. Furthermore, we observe that with the help of permittivity noise our stochastic Epileptor model can trigger the seizure dynamics even when it operates in the theoretical nonepileptogenic regime. These findings establish a deep mechanistic understanding on how stochastic fluctuations of permittivity coupling shape the seizure dynamics in partial epilepsy,and provide insightful biological implications.

关键词： partial epilepsy seizures dynamics Epileptor model slow permittivity variable stochastic fluctuations of permittivity coupling

Preparation of SiO_2/TiO_2 Janus particles by electrostatic assembly,hydrolysis and calcination

在线全文

学校读者我要写书评

暂无评论

Particuology 2013年第5期11卷 574-580页

作者： Baoliang Zhang Qiuyu Zhang Hepeng Zhang Xinlong Fan dezhong Yin Xiangjie Li Wei Li Department of Applied Chemistry College of ScienceNorthwestern Polytechnical University

This paper describes a novel chemical method for preparing SiO2/TiO2 Janus particles. First, polystyrene （PSt）/SiO2 particles with a raspberry-like structure are prepared by electrostatic assembly. The influences of the reaction time of sulfonation and the treatment times of polyelectrolyte solutions （PDADMAC, PSS） on PSt and SiO2 are investigated with respect to the surface charge density of the particles. SiO2/TiO2 Janus particles are then obtained by hydrolysis of butyl titanate on the surface of PSt/SiO2 particles followed by a calcination process. Particle size analyzer, Zeta potential instrument, FTIR, TEM and SEM are used to characterize the particle size, the amount of charge on the surface of PSt and SiO2 particles and the compositions and morphologies of PSt/SiO2, SiO2/Ti02 and PSt/SiO2/Ti02. The diameters of the PSt, SiO2, PSt/Si02 and SiO2/Ti02 particles are 2.0 t^m, 303 nm, 2.7 bcm and 330 nm, respectively.

关键词： Janus particlesElectrostatic assemblyHydrolysisCalcination

Efficient dehydration of carbohydrates to 5-hydroxymethylfurfural in ionic liquids catalyzed by tin(Ⅳ) phosphonate and zirconium phosphonate

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2013年第11期56卷 1578-1585页

作者： NING Hui SONG JinLiang HOU MinQiang YANG dezhong FAN HongLei HAN BuXing Beijing National Laboratory for Molecular Sciences Institute of Chemistry Chinese Academy of Sciences

In this work,we synthesized tin(IV)phosphonate(SnBPMA)and zirconium phosphonate(ZrBPMA)by the reaction of SnCl4·5H2O or ZrOCl2·8H2O with N,N-bis(phosphonomethyl)aminoacetic acid,which was synthesized from a biomaterial glycine through a Mannich-type *** SnBPMA and ZrBPMA were very efficient heterogeneous catalysts for the dehydration of fructose to produce 5-hydroxymethylfurfural(HMF),and the SnBPMA had higher activity than the *** effects of solvents,temperature,reaction time,and reactant/solvent weight ratio on the reaction catalyzed by SnBPMA were *** was demonstrated that the yield of HMF could reach 86.5%with 1-ethyl-3-methylimidazolium bromide([Emim]Br)as solvent,and the SnBPMA and SnBPMA/[Emim]Br catalytic system could be reused five times without considerable reduction in catalytic *** study indicated that the SnBPMA and ZrBPMA in[Emim]Br were also effective for the dehydration of sucrose and inulin to produce HMF with satisfactory yields.

关键词： fructose inulin sucrose dehydration 5-hydroxymethylfurfural heterogeneous catalysts

Facile preparation and characterization of novel oleanane-type triterpene functionalized β-cyclodextrin conjugates

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2019年第3期30卷 690-693页

作者： Pingxuan Jiao Shouxin Wang Shuobin Liang Man Li Qianqian Gao dezhong Ji Yingying Chen Haiwei Li Fuxiang Ran Yongmin Zhang Lihe Zhang Demin zhou Sulong Xiao State Key Laboratory of Natural and Biomimetic Drugs School of Pharmaceutical Sciences Peking University School of Pharmacy Jining Medical University Sorbonne Universite Institut Parisien de Chimie Moleculaire CNRS UMR 8232 State Key Laboratory of Phytochemistry and Plant Resources in West China Kunming Institute of Botany Chinese Academy of Sciences

Oleanolic acid(OA) and echinocystic acid(EA), two naturally occurring pentacyclic oleanane triterpenes,are gaining increasing attention due to their promising pharmacological activities. Conjugation with amphiphilic α(β)-cyclodextrin(CD) via "click chemistry" can improve their solubility and anti-HCV entry potency. In the present work,four water-soluble β-CD-pentacyclic triterpene conjugates were designed and synthesized, in which OA and EA was coupled to one of the primary hydroxyl groups of β-CD via ester and amide bonds. The structures of the conjugates were unambiguously determined by ~1H NMR, ^(13)C NMR and HRMS or MALDI-TOF-MS. All the conjugates showed lower hydrophobicity(AlogP) than their parent compounds and no significant cytotoxicity was found to HL-60, A549, Hela and Bel-7402 cells at concentrations up to 10 μmol/L. Further anti-HCV entry activity and mechanism studies are under way in our laboratory.

关键词： β-Cyclodextrin DIBAL-H Oleanolic acid Echinocystic acid Synthesis

Application of Fractal Theory in the Synthesis of Nano-sized 3Y-TZP Superplastic Ceramic Materials

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2001年第1期17卷 121-122页

作者： Guofeng WANG Kaifeng ZHANG and dezhong WU School of Materials Science and Engineering, Harbin Institute of Technology Harbin 150001, China Sch. of Mater. Sci. Harbin Inst. of Technol. Harbin 150001 China

Nano-sized 3Y-TZP powders were Synthesized by two methods. A fractal software was developed. A new and convenient method for characterizing the quality of Synthetic process by using fractal theory was obtained.

关键词： Nano TZP

Failure mechanism and control technology of longwall coalface in large-cutting-height mining method

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2016年第1期26卷 111-118页

作者： Wang Jiachen Yang Shengli Kong dezhong College of Resources & Safety Engineering China University of Mining & Technology Beijing 100083 China State Key Laboratory of Coal Resources & Safe Mining Beijing 100083 China China Coal Industry Top-Coal Caving Mining Engineering Research Center Beijing 100083 China

The stability control of longwall coalface is the key technology of large-cutting-height mining ***,a systematic study of the factors that affect coalface stability and its control technology is required in the development of large-cutting-height mining method in China. After the practical field observation and years of study,it was found that the more than 95% of failures in coalface are shear failure. The shear failure analysis model of coalface has been established,that can perform systematic study among factors such as mining height,coal mass strength,roof load,support resistance,and face flipper protecting plate horizontal force. Meanwhile,sensitivity analysis of factors influencing coalface stability showed that improving support capacity,cohesion of coal mass and decreasing roof load of coalface are the key to improve coalface stability. Numerical simulation of the factors affecting coalface stability has been performed using UDEC software and the results are consistent with the theoretical analysis. The coalface reinforcement technology of large-cutting-height mining method using the grouting combined with coir rope is presented. Laboratory tests have been carried out to verify its reinforcement effect and practical application has been implemented in several coal mines with good *** has now become the main technology to reduce longwall coalface failure of large-cutting-height mining method.

关键词： Large-cutting-height mining methodLongwall coalfaceShear failureCoalface stability control technology