检索结果-南通市图书馆

Disc-cutter induced rock breakage mechanism for TBM excavation in rock masses with different joint shear strengths

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Underground Space 2024年第6期19卷 119-137页

作者： Bolong Liu Bo Li Liang Zhang Rui Huang Huicai Gao Shilin luo Tao Wang Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province Shaoxing UniversityShaoxing 312000China College of Civil Engineering Tongji UniversityShanghai 200092China College of Civil and Architectural Engineering Xi’an University of Science and TechnologyXi’an 710054China College of Civil Engineering Changsha UniversityChangsha 410022China School of Transportation Science and Engineering Harbin Institute of TechnologyHarbin 150040China Chongqing Research Institute of Harbin Institute of Technology Harbin Institute of TechnologyChongqing 401151China

When tunnel boring machines(TBMs)excavate through jointed rock masses,the cutting efficiency is strongly affected by the shear strength of joints,the mechanism of which,however,remains poorly *** this study,a series of disc-cutter indentation tests were conducted on granite rock mass specimens with different joint shear *** the indentation,the cracking process was recorded by a digital image correlation(DIC)*** deformation and strength of specimens,cracking behavior,rock breakage mode and cutting efficiency were quantitatively *** addition,to investigate the combined effects of joint shear strength,orientation and spacing on the rock breakage mechanism,numerical rock mass models were established based on a particle flow code *** results reveal that the cracking of primary and secondary cracks changes from the mixed shear-tensile to tensile mode in the initial stage,while the joint shear strength does not affect the cracking mode in the subsequent propagation *** rock breakage mode is classified to an internal block breakage mode,a cross-joint breakage mode and a cutters-dependent breakage *** cross-joint breakage mode is optimal for improving the cutting *** simulation results reveal that the increase in the joint shear strength changes the internal block breakage mode to cross-joint breakage mode for rock masses of particular ranges of joint orientation and *** findings provide basis for improving the TBM cutting efficiency through jointed rock masses.

关键词： Indentation test Joint shear strength Disc cutter Rock breakage mechanism Cutting efficiency

Determinants of Public Goods Investment in Rural Communities in Mountainous Areas of Sichuan Province, China

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 2014年第3期11卷 816-824页

作者： GUO Shi-li LIU Shao-quan luo Ren-fu ZHANG Lin-xiu Institute of Mountain Hazards and Environment Chinese Academy of Sciences Economic Research Center for Western China Southwestern University of Finance and Economics Graduate University of Chinese Academy of Sciences Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences

This study aims to investigate two important issues: what are the determinants of public goods investment and what is the government's investment behavior in mountainous areas. The impacts of natural conditions, target, and demand elements on public goods investment are analyzed with statistical method, and the determinants of public goods investment in the areas are obtained by using population-weighted and stepwise regression models with Eviews6.0 software with survey data in 2008 and calculated data based on GIS of 20 typical villages in mountainous regions in Sichuan, China. The results showed:(1) natural conditions are the important determinants of public investment. Mountainous villages with steep slope have relatively high levels of investment;(2) concentration of population and the educational levels of the village leaders also have important impacts on public goods investment;(3) the government is more concerned with public investment resources particularly in areas characterized by fragile ecological environment and poor agricultural output. These results suggest that the current investment strategy helps to reduce disparities in regional development.

关键词： Determinants Eviews6.0 GIS Public Investment Regression Analysis Rural Development

Modulating 3D memristor synapse by analog spiking pulses for bioinspired neuromorphic computing

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2018年第8期61卷 75-81页

作者： Qi Liu XuMeng Zhang Qing luo XiaoLong Zhao HangBing Lv ShiBing Long Ming Liu Key Laboratory of Microelectronics Device&Integrated Technology Institute of MicroelectronicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

Memristor based artificial synapses have demonstrated great potential for bioinspired neuromorphic computing in recent years. To emulate synaptic fimctions, such as short-term plasticity and long-term potentiation/depression, square pulses or combined complex pulse groups are applied on the device. However, in biological neuron systems, the action potentials are analog pulses with similar amplitudes. Furthermore, in biological systems, the intensity of the stimulus is coded into the frequency of action potentials to modulate the weight of synapses. Toward this programming method, we applied a series of analog spiking pulses with same peaks on Ru/TiOJTiN 3D memristor to emulate synaptic functions, such as long-term potentiation/depression and synaptic saturation. Moreover, we demonstrated the conductance change of the device under different stimulus frequencies of analog spiking pulses and described the statistical results of conductance change value, which shows that the device conductance has a larger change value under a higher spiking frequency with identical pulse number. These results show that the analog spiking pulses can well modulate the memristor-based synaptic weight and have a great potential for bioinspired computing in the future.

关键词： 3D memristor analog spiking pulses artificial synapse spiking frequency

Intravitreal injection of resveratrol inhibits laser-induced murine choroidal neovascularization

在线全文

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2020年第6期13卷 886-892页

作者： Hui-Ming Zhang Xiao-Hua Li Mingjiazi Chen Jing luo Department of Dermatology the Second Xiangya HospitalCentral South UniversityChangsha 410011Hunan ProvinceChina Hunan Key Laboratory of Medical Epigenomics Changsha 410011Hunan ProvinceChina Department of Pathology and Ophthalmology Keck School of Medicine at University of Southern CaliforniaLos AngelesCalifornia 90033USA Henan Provincial People's Hospital/Henan Eye Hospital Henan Eye InstituteHenan Key Laboratory of Ophthalmology and Vision Science/Department of OphthalmologyPeople’s Hospital ofZhcngzliou University/Department of OphthalmologyPeople's Hospital of Henan UniversityZhengzhou 450003Henan ProvinceChina 5Department of Ophthalmologythe Second Xiangya I IospitalCentral South UniversityChangsha 410011Hunan ProvinceChina

AIM:To determine the effects of intravitreal resveratrol(RSV)on murine laser-induced choroidal neovascularization(CNV).METHODS:The toxicity of RSV to choroidal endothelial cell(CEC)was measured using thiazolyl blue tetrazolium bromide(M一)*** of RSV on choroidal endothelial cell(CEC)migration were evaluated with a modified Boyden chamber assay,while tube formation was evaluated in a 2-D gel *** was induced by laser photocoagulation in *** effects of intravitreal injection of RSV on CNV development were evaluated by fluorescein angiography(FA),confocal analysis of isolectin B4 labeled choroidal flat mounts,and histologic examination of CNV *** was used to analyze the expression and phosphorylation of vascular endothelial growth factor receptor 2(VEGFR2).RESULTS:No significant cell toxicity was observed in CEC if the concentration of RSV was less than 200 pmol/L(P>0.05).RSV inhibited vascular endothelial growth factor(VEGF)-induced CEC migration(P<0.05)and tube formation(P<0.05)***,intravitrealinjectionof RSV significantly inhibited laser induced CNV formation in *** FA leakage,CNV volume and CNV area analysis revealed that there were 41%,45%,and 58%reduction in RSV-treated eyes(1.691±0.1032,178163±78623μm^3 and 6508±619.0μm^2,respectively)compared with those in control(2.724±0.08447,379676±98382μm3and16576±2646μm^2,respectively;P<0.05).Phospho-VEGFR2expression was much weaker in the sections of CNV lesions in RSV injected mice compared with that in control(P<0.05).CONCLUSION:Intravitreal injection of RSV exerts an inhibitory effect on CNV,which may through suppressing endothelial cell migration,tube formation and VEGFR2 phosphorylation.

关键词： resveratrol intravitreal injection choroidal neovascularization vascular endothelial growth factor receptor 2 tube formation murine

Security-Reliability Analysis and Optimization for Cognitive Two-Way Relay Network with Energy Harvesting

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Communications 2024年第11期21卷 163-179页

作者： luo Yi Zhou Lihua Dong Jian Sun Yang Xu Jiahui Xi Kaixin Hunan Provincial Key Laboratory of Intelligent Computing and Language Information Processing Hunan Normal UniversityChangsha 410081China School of Electronic Information Central South UniversityChangsha 410075China

This paper investigates the security and reliability of information transmission within an underlay wiretap energy harvesting cognitive two-way relay *** the network,energy-constrained secondary network(SN)nodes harvest energy from radio frequency signals of a multi-antenna power *** SN sources exchange their messages via a SN decode-and-forward relay in the presence of a multiantenna eavesdropper by using a four-phase time division broadcast protocol,and the hardware impairments of SN nodes and eavesdropper are *** alleviate eavesdropping attacks,the artificial noise is applied by SN *** physical layer security performance of SN is analyzed and evaluated by the exact closed-form expressions of outage probability(OP),intercept probability(IP),and OP+IP over quasistatic Rayleigh fading ***,due to the complexity of OP+IP expression,a self-adaptive chaotic quantum particle swarm optimization-based resource allocation algorithm is proposed to jointly optimize energy harvesting ratio and power allocation factor,which can achieve security-reliability tradeoff for *** simulations demonstrate the correctness of theoretical analysis and the effectiveness of the proposed optimization algorithm.

关键词： artificial noise energy harvesting cognitive two-way relay network hardware impairments physical layer security security-reliability tradeoff self-adaptive quantum particle swarm optimization

A Convolution-Based System for Malicious URLs Detection

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2020年第1期62卷 399-411页

作者： Chaochao luo Shen Su Yanbin Sun Qingji Tan Meng Han Zhihong Tian Institute of Computer Application China Academy of Engineering PhysicsMianyang621054China Cyberspace Institute of Advanced Technology Guangzhou UniversityGuangzhou510006China School of Mechanical and Electrical Engineering Heilongjiang State Farm Science Technology Vocational CollegeHarbin150431China Department of Computing and Software Engineering Kennesaw State UniversityKennesawGA 30144USA

Since the web service is essential in daily lives,cyber security becomes more and more important in this digital *** Uniform Resource Locator(URL)is a common and serious threat to *** hosts unsolicited content and lure unsuspecting users to become victim of scams,such as theft of private information,monetary loss,and malware ***,it is imperative to detect such ***,traditional approaches for malicious URLs detection that based on the blacklists are easy to be bypassed and lack the ability to detect newly generated malicious *** this paper,we propose a novel malicious URL detection method based on deep learning model to protect against web ***,we firstly use auto-encoder to represent ***,the represented URLs will be input into a proposed composite neural network for *** order to evaluate the proposed system,we made extensive experiments on HTTP CSIC2010 dataset and a dataset we collected,and the experimental results show the effectiveness of the proposed approach.

关键词： CNN anomaly detection web security auto-encoder deep learning

Steroidal alkaloids from the bulbs of Fritillaria monatha

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 Chemical Letters 2008年第5期19卷 544-546页

作者： Hong Ning Liu Fei Li Yong Ming luo Wei Feng Zhu Jiangxi University of Traditional Chinese Medicine Nanchang 330004 China

Two new Steroidal alkaloids, named pengbeisine A and pengbeisine B, were isolated from the fresh bulbs of Fritillaria monatha Migo. along with a known alkaloid. The structures were characterized as 22,26-imino-17, 23-oxido-5α-jerv-6-oxo-2α,3β-diol and 22, 26-imino-17, 23-oxido-5α-jerv-6-oxo-2β,3α-diol on the basis of spectroscopic methods.

关键词： Fritillaria monatha Migo Steroidal alkaloids Pengbeisine A Pengbeisine B

Interfacial structure design of MXene-based nanomaterials for electrochemical energy storage and conversion

在线全文

学校读者我要写书评

暂无评论

InfoMat 2020年第6期2卷 1057-1076页

作者： Jianmin luo Edward Matios Huan Wang Xinyong Tao Weiyang Li Thayer School of Engineering Dartmouth CollegeHanoverNew Hampshire College of Materials Science and Engineering Zhejiang University of TechnologyHangzhouZhejiangChina

2D transition metal carbides,carbonitrides,and nitrides known as MXenes possess high electrical conductivity,large redox active surface area,rich surface chemistry,and tunable *** from these exceptional chemical and physical properties,the applications of MXenes for electrochemical energy storage and conversion have attracted increasing research interests around the ***,the electrochemical performances of MXenes are directly dependent on their synthesis conditions,interfacial chemistries and structural *** this review,we summarize the synthesis techniques of MXenes,as well as the recent advances in the interfacial structure design of MXene-based nanomaterials for electrochemical energy storage and conversion ***,we provide an in-depth discussion on the relationship between interfacial structure and electrochemical performance from the perspectives of energy storage and electrocatalysis ***,the challenges and insights for the future research of interfacial structure design of MXenes are outlined.

关键词： electrocatalysis electrochemical energy storage interlayer space MXene structure design

A new procedure combining GC-MS with accelerated solvent extraction for the analysis of phthalic acid esters in contaminated soils

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2013年第1期7卷 31-42页

作者： Tingting MA Ying TENG Peter CHRISTIE Yongming luo Yongshan CHEN Mao YE Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 China Graduate University of the Chinese Academy of Sciences Beijing 100049China Agri-Environment Branch Agri-Food and Biosciences Institute Newforge Lane Belfast BT9 5PX United Kingdom State key Laboratory of Environment Simulation and Pollution control (Jomt) Tsinghua University Beijing 100084 China State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 China

An optimized procedure based on gas chromatography-mass spectrometry (GC-MS) combined with accelerated solvent extraction (ASE) is developed for the analysis of six phthalic acid esters (PAEs), which are priority soil pollutants nominated by United States Environmental Protection Agency (USEPA). Quantification of PAEs in soil employs ultrasonic extraction (UE) (USEPA 3550) and ASE (USEPA 3545), followed by clean up procedures involving three different chromatography columns and two combined elution methods. GC-MS conditions under selected ion monitoring (SIM) mode are described and quality assurance and quality control (QA/QC) criteria with high accuracy and sensitivity for target analytes were achieved. Method reliability is assured with the use of an isotopically labeled PAE, di-n-butyl phthalate-d4 (DnBP-D4), as a surrogate, and benzyl benzoate (BB) as an internal standard, and with the analysis of certified reference materials (CRM). QA/QC for the developed procedure was tested in four PAE-spiked soils and one PAE-contaminated soil. The four spiked soils were originated from typical Chinese agricultural fields and the contaminated soil was obtained from an electronic waste dismantling area. Instrument detection limits (IDLs) for the six PAEs ranged 0.10–0.31 μg·L?1 and method detection limits (MDLs) of the four spiked soils varied from a range of 20–70 μg·kg?1 to a range of 90–290 μg·kg?1. Linearity of response between 20 μg·L?1 and 2 mg·L?1 was also established and the correlation coefficients (R) were all>0.998. Spiked soil matrix showed relative recovery rates between 75 and 120% for the six target compounds and about 93% for the surrogate substance. The developed procedure is anticipated to be highly applicable for field surveys of soil PAE pollution in China.

关键词： phthalic acid esters quality assurance and quality control soil type accelerated solvent extraction certified reference materials