检索结果-南通市图书馆

Failure evolution and disaster prediction of rock under uniaxial compression based on non-extensive statistical analysis of electric potential

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

International Journal of Mining Science and Technology 2024年第7期34卷 975-993页

作者： Tiancheng shan Zhonghui Li Haishan Jia Enyuan Wang Xiaoran Wang Yue Niu Xin Zhang dong Chen shan Yin Quancong Zhang State Key Laboratory of Coal Mine Disaster Prevention and Control China University of Mining and TechnologyXuzhou 221116China National Engineering Research Center for Coal Gas Control China University of Mining and TechnologyXuzhou 221116China School of Safety Engineering China University of Mining and TechnologyXuzhou 221116China State Key Laboratory for Fine Exploration and Intelligent Development of Coal Resources China University of Mining and TechnologyXuzhou 221116China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China

Rock failure can cause serious geological disasters,and the non-extensive statistical features of electric potential(EP)are expected to provide valuable information for disaster *** this paper,the uniaxial compression experiments with EP monitoring were carried out on fine sandstone,marble and granite samples under four displacement *** Tsallis entropy q value of EPs is used to analyze the selforganization evolution of rock *** the influence of displacement rate and rock type on q value are explored by mineral structure and fracture modes.A self-organized critical prediction method with q value is *** results show that the probability density function(PDF)of EPs follows the q-Gaussian *** displacement rate is positively correlated with q *** the displacement rate increasing,the fracture mode changes,the damage degree intensifies,and the microcrack network becomes *** influence of rock type on q value is related to the burst intensity of energy release and the crack fracture *** q value of EPs can be used as an effective prediction index for rock failure like b value of acoustic emission(AE).The results provide useful reference and method for the monitoring and early warning of geological disasters.

关键词： Electric potential Non-extensive statistical feature Displacement rate q-Gaussian distribution Precursor prediction Rock materials

Photocatalytic vinyl radical-mediated multicomponent 1,4-/1,8-carboimination across alkynes and olefins/(hetero)arenes

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第2期67卷 558-567页

作者： shan-shan Li Yu-Shi Jiang Xue-Ling Luo Xuming Ran Yuqiang Li dong Wu Cheng-Xue Pan Peng-Ju Xia School of Chemistry and Pharmaceutical Sciences Guangxi Normal UniversityGuilin541004China shanghai Artificial Intelligence Laboratory Shanghai200433China The Institute for Advanced Studies Wuhan UniversityWuhan430064China

We developed a highly selective and efficient multicomponent transformation by utilizing alkynes and olefins/(hetero)arenes through photoinduced energy-transfer *** reaction involves the formation of three distinct chemical bonds,namely C(sp~3)–C(sp~2),C(sp~2)–C(sp~3),and C(sp~3)–N,in a single coordinated *** strategy used a vinyl radical-mediated radical relay approach under mild conditions,exhibiting a broad substrate scope(>70 examples),excellent functional-group tolerance,and remarkable regio-and *** the utilization of a combination of experimental techniques and density functional theory(DFT),we delved deeper into the mechanistic intricacies of this distinctive *** revealed that the selective radical addition to electron-deficient alkynes,rather than olefins,was governed by the inherent reactivity of alkyl *** discovery presented a highly effective approach for the synthesis of stereodefined multisubstituted alkenes.

关键词： alkyne-olefin coupling DFT studies regio-and anti-stereoselectivity multisubstituted alkenes

Regulating element distribution to improve magnetic properties of sintered Nd–Fe–B/Tb–Fe–B composite magnets

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第7期28卷 465-469页

作者： Zhu-Bai Li Jing-Yan Zuo dong-shan Wang Fei Liu Xue-Feng Zhang Key Laboratory of Integrated Exploitation of Bayan Obo Multi-Metal Resources Inner Mongolia University of Science and Technology Baotou 014010 China School of Science Inner Mongolia University of Science and Technology Baotou 014010 China

Nd content was varied in Nd13.2-xFe80.8+xB6(x = 0, 0.5, 1, and 1.5) to optimize the magnetic properties of sintered Nd–Fe–B/Tb–Fe–B composite magnets, which were prepared by mixing 9 g of Nd–Fe–B with 1 g of Tb17Fe75B8 *** conventional magnets, by reducing Nd content, the coercivity of 10.4 kOe in Nd13.2Fe80.8B6 decreases to 7.2 kOe in Nd12.2Fe81.8B6;meanwhile, in Nd–Fe–B/Tb–Fe–B magnets the coercivity does not decrease when reducing Nd *** the intergranular phase, the Tb content increases owing to the reducing Nd content of the Nd–Fe–B alloy in the sintered composite ***, the excess Tb in Tb17Fe75B8 enters the intergranular phase, and more Tb atoms can substitute for Nd at the grain boundary of the Nd–Fe–B phase, leading to a more significant increase in *** remanence increases with reducing Nd content, and the energy product of 39.1 MGOe with a high coercivity of 21.0 kOe is obtained in Nd12.2Fe81.8B6/Tb17Fe75B8 *** investigations show that magnetic properties can be further improved by regulating the element distribution in sintered composite magnets.

关键词： composite magnets coercivity intergranular phase element distribution

防城金花茶国家级自然保护区罗浮柿种群空间分布格局及关联分析

在线全文

学校读者我要写书评

暂无评论

安徽农业科学 2024年第1期52卷 121-124页

作者：廖南燕陈善栋李武峥覃毅唐业杰蔡中伦广西壮族自治区防城金花茶国家级自然保护区管理中心广西防城港538021 广西师范大学生命科学学院广西桂林541006

以防城金花茶国家级自然保护区罗浮柿优势种群为研究对象,采用成对相关函数g(r)和g_(12)(r)对种群不同发育时期的空间格局和关联性进行分析。结果显示:罗浮柿树种群在不同径级上的分布呈“单峰”型。幼树与中树在研究尺度内以聚集分布为... 详细信息

以防城金花茶国家级自然保护区罗浮柿优势种群为研究对象,采用成对相关函数g(r)和g_(12)(r)对种群不同发育时期的空间格局和关联性进行分析。结果显示:罗浮柿树种群在不同径级上的分布呈“单峰”型。幼树与中树在研究尺度内以聚集分布为主,而幼苗和成树则显示随机分布的趋势。幼苗与幼树、中树、成树在一定小中尺度范围内呈正相关。幼树和中树在研究尺度主要以正向的促进关系为主,幼树、中树与成树则显示为不相关。罗浮柿种群内的更新苗木储备丰富,种群呈现稳定增长趋势。罗浮柿种群的分布格局及其关联性随种群密度和树木大小的改变而变化。

关键词：罗浮柿种群龄级空间分布格局防城金花茶国家级自然保护区

Experimental models of type 2 diabetic nephropathy

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2013年第3期126卷 574-577页

作者： HU Yuan-yuan YE shan-dong Department of Endocrinology Anhui Provincial Hospital Affiliated to Anhui Medical University Hefei Anhui 230001 China

With the rapidly rising incidence of diabetes, one of its complications, diabetic nephropathy （DN） is becoming one of the most common causes of end-stage renal disease in many countries. Reliable animal models of DN are a valuable tool for identifying the molecular mechanisms responsible for this disease and preclinical development of new therapeutic strategies. Various types of animal models have been used in the past; the induced methods and characteristics of these commonly used animal models were summarized in this review.

关键词： diabetic nephropathy diabetes

Pioglitazone inhibits the expression of nicotinamide adenine dinucleotide phosphate oxidase and p38 mitogen-activated protein kinase in rat mesangial cells

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2013年第21期126卷 4054-4059页

作者： Wang shan Ye shan-dong Sun Wen-jia Hu Yuan-yuan Anhui Med Univ Anhui Prov Hosp Dept Endocrinol Hefei 230001 Anhui Peoples R China

Background Oxidative Stress and p38 mitogen-activated protein kinase （p38MAPK） play a vital role in renal fibrosis. Pioglitazone can protect kidney but the underlying mechanisms are less clear. The purpose of this study was to investigate the effect of pioglitazone on oxidative stress and whether the severity of oxidative stress was associated with the phosphorylation level of p38MAPK.

关键词： nicotinamide adenine dinucleotide phosphate oxidase p38 mitogen-activated protein kinase oxidative stress,"pioglitazone mesangial cells

Light-weighted services awareness scheme of the IP and optical converged network

在线全文

学校读者我要写书评

暂无评论

Optoelectronics Letters 2019年第6期15卷 444-448页

作者： BAI Hui-feng WANG dong-shan WANG Li-cheng HUO Chao Beijing Smart Chip Microelectronics Technology Company Limited

As internet services newly emerge with diversity and complexity, great challenges and demands are presented to both IP network and optical network to support various services. Aimed to solve this problem, this paper proposes a light-weighted echo-state-network(LW-ESN) based services awareness scheme of the software defined IP and optical converged network. This LW-ESN model adopts the ring topology structure inside and generates the probability output result to determine the quality of service policy of IP and optical converged network. Moreover, the LW-ESN based service awareness engine is also designed in controller node of IP and optical converged network to perform services awareness by obtaining service traffic parameters from IP and optical layers, together with necessary working procedure. Simulation results show that the proposed approach is able to improve the services-oriented supporting ability in terms of blocking rate and delay time.

关键词： services service network

Mitigation of Deane and Hamill phenomenon in gallium nitride high-voltage power supply for electric propulsion system application

在线全文

学校读者我要写书评

暂无评论

High Voltage 2024年第1期9卷 252-265页

作者： Minghai dong Hui Li shan Yin Kye Yak See Yingzhe Wu Xiong Xin School of Aeronautics&Astronautics University of Electronic Science and Technology of ChinaChengduChina School of Electrical&Electronic Engineering Nanyang Technological UniversitySingaporeSingapore School of Automation Engineering University of Electronic Science and Technology of ChinaChengduChina Innoscience(Shenzhen)Semiconductor Co.Ltd. ShenzhenChina

The step-up resonant converters are widely adopted to provide high voltage in kV-level for electric propulsion system due to their high efficiency,low mass,modularisation,and high-power *** bipolar Cockcroft-Walton voltage multiplier(BiCWVM)is a major circuit that steps up the voltage in the resonant ***,the diode nonlinearity in BiCWVM can introduce self-sustained quasi-periodic oscillations in the voltage and current waveforms,which is commonly known as the Deane and Hamill(DH)*** oscillation can lead to higher magnetic loss and control failure,and it is more likely to present in the gallium nitride-based converter due to the highfrequency *** authors aim to investigate and mitigate the DH phenomenon systematically so that proper mitigation can be *** facilitate the investigation,the circuit before the BiCWVM in the converter is derived and modelled as a voltage source v_(m)and a series inductor L_(sy).Also,the reverse recovery process of the diode in the BiCWVM can be represented by a piecewise-linear(PWL)model,with the simplified circuit and PWL model,the relationship between voltage and current under different operating conditions can be determined with *** relationship allows to understand the mechanism of diode reverse recovery in BiCWVM that leads to DH ***,a hybrid-/full-silicon carbide(SiC)design is proposed to mitigate the DH phenomenon,which is verified experimentally for a 300-kHz,5-W,20-V/1.5-kV GaN-based step-up resonant converter.

关键词： power resonant high

Research on Bast Fiber Extracted from the White Bark of Three Species in the Genus Broussonetia

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 Polymer Science 2024年第6期42卷 729-738页

作者： shan-shan Jin Si-Nong Wang Yan-Yan Huang Jing-Yu Zhang Peng Liu Hui Yu Hong-dong Zhang Yu-Liang Yang Institute for Preservation and Conservation of Chinese Ancient Books Fudan University LibraryFudan UniversityShanghai200433China State key laboratory of Molecular Engineering of polymers Department of Macromolecular ScienceFudan UniversityShanghai200433China

Against the backdrop of a global paper resource shortage,there is a growing need to identify fast-growing tree species capable of producing long-lasting *** plant species namely Broussonetia kazinoki,Broussonetia papyrifera and hybrid paper mulberry,belong to the Broussonetia genus,were collected from China to study their white bark suitability for pulp and *** chemical composition revealed that the holocellulose content in Broussonetia kazinoki and Broussonetia papyrifera was more than 80%.The molecular weight distribution of several holocellulose/α-cellulose is observed by GPC,which allows us to better observe the changes of various components on the molecular *** yield,lignin,whiteness,and molecular weight of the pulps obtained by NaOH treatment were *** microscope was used to characterize the fiber length-width ratio and ***,the improvement of the fiber rigidity method based on the Kratky-Porod chain model makes it more theoretical and further reveals the influencing factors of fiber *** study demonstrates the high potentiality of these three species for papermaking applications.

关键词： Broussonetia genus Cellulose Alkaline pulping Kratky-Porod chain model Fiber rigidity