检索结果-南通市图书馆

Energy analysis for damage and catastrophic failure of rocks

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2011年第S1期54卷 199-209页

作者： xie HePing 1,2,LI LiYun 2,1,JU Yang 2,PENG RuiDong 2 & YANG yongming 2 1 Sichuan University,Chengdu 610065,China 2 State Key Laboratory of Coal Resources and Safe Mining,Beijing Key Laboratory of Fracture and Damage Mechanics of Rock and Concrete,China University of Mining and Technology,Beijing 100083,China Sichuan University Chengdu China State Key Laboratory of Coal Resources and Safe Mining Beijing Key Laboratory of Fracture and Damage Mechanics of Rock and Concrete China University of Mining and Technology Beijing China

The development history and current state of studies on the characteristics and mechanisms of deformation and failure of rock materials were briefly reviewed from the viewpoint of *** main scope and the achievable objectives of the energy-based research system were *** was validated by experiments that the damage process of rocks can be well described by the rock damage evolution equation established based on energy *** was found from the uniaxial compression and biaxial compression tests that only a small proportion of the total input energy in hard rocks is dissipated before peak load and a large proportion in soft rocks is dissipated before peak *** both hard and soft rocks,the energy dissipated after peak load accounts for a greater *** energy would be required for rock failure under equal biaxial compression than under unequal biaxial *** total absorbed energy is different for rock failure under high-rate loading and low-rate *** fragmented failure pattern usually corresponds to higher energy *** mesoscopic analysis on the damage and failure of bedded salt rocks showed that the energy dissipation is prominent and the total absorbed energy for rock failure is low when cracks propagate in the weak mud interlayer while it is contrary when cracks propagate in the salt *** energy accumulation,transfer,dissipation and release during the failure process of tunnel with impending failure under disturbance were analyzed theoretically based on the elastoplastic mechanics ***,the spatial distribution of energy dissipation and energy release of fractured rocks under unloading was simulated *** was demonstrated that energy is likely to be released from the weakest surface under compression,which triggers the global failure of rocks.

关键词： rock deformation failure energy accumulation energy dissipation energy release

Status of aquatic organisms resources and their environments in Yangtze River system(2017-2021)⋆

在线全文

学校读者我要写书评

暂无评论

Aquaculture and Fisheries 2024年第5期9卷 833-850页

作者： Haile Yang Li Shen Yongfeng He Huiwu Tian Lei Gao Jinming Wu Zhigang Mei Nian Wei Lin Wang Tingbing Zhu Feifei Hu Jinling Gong Hongchun Du Xinbin Duan Huatang Deng Daoqun Wang Fengyue Zhu Yunfeng Li Fan Wu Huijun Ru Yan Zhang Junyi Li Junlin Yang Yuntao Zhou Dongdong Fang Yinping Wang Danqing Lin Yanping Yang Peijie Li Silei Liu Jian Yang Ping Zhuang Sikai Wang Tao Zhang Gang Yang Wenbo Yang Lilai Yuan Kun Cao Shuo Xu Huiyuan Liu Zhiqiang Liang Chongrui Wang Hong Li Xiping Yuan Xin Yang Yilong Fu Yanping Zhang Haixin Zhang Zhiying Tao Sheng Wang Xiaoping Gao Binsong Jin Kemao Li Guojie Wang Shenglong Jian Yingqin Li Chenjiang Xue Chunyun Lei Shaowei Xue Yi Sun Bin Zhu Ke Shao Xingkun Hu Meihua Xiong Jun Du Bin He Tao Yan Yingying Huang Yuanchao Zou Biwen xie yongming Wang Bin Li Fei Liu Yaoyao Zhang Fei Fan Zhijian Wang Jing Huang Haoran Gu Hailong Ge Yan Dan Yan Li Shuqiao Wang Chuang Zhang Lu Zhou Xue Wang Sheng Zeng Yan Xiang Xugang He Jianhui Qin Chengxing Xia Jie Hou Yifu Shi Lifang Gao Zhiqiang Zhu Hongbao Shen Yun Du Xuejun Duan Jiawu Xiong Deguo Yang Shaoping Liu Zhaohui Ni Hui Zhang Kai Liu Feng Zhao Yingren Li Jianwei Wang Qiwei Wei Yangtze River Fisheries Research Institute Chinese Academy of Fishery SciencesWuhan430223China Institute of Hydrobiology Chinese Academy of SciencesWuhan430072China Fishery Resource and Environment Research Center Chinese Academy of Fishery SciencesBeijing100141China Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization Ministry of Agriculture and Rural AffairsFreshwater Fisheries Research CenterChinese Academy of Fishery SciencesWuxi214081China East China Sea Fisheries Research Institute Chinese Academy of Fishery SciencesShanghai200090China Institute of Fisheries Engineering Chinese Academy of Fishery SciencesBeijing100141China Hunan Fisheries Science Institute Changsha410153China Jiangxi Fisheries Research Institute Nanchang330039China Jiujiang Academy of Fishery Sciences Jiujiang332000China School of Life Sciences Nanchang UniversityNanchang330031China Qinghai Provincial Fishery Technology Extension Center Xining810012China Yunnan Academy of Fishery Sciences Kunming650111China Institute of Hydroecology Ministry of Water Resources and Chinese Academy of SciencesWuhan430079China Fisheries Institute Sichuan Academy of Agricultural SciencesChengdu611731China School of Life Sciences Neijiang Normal UniversityNeijiang641100China School of Life Sciences Southwest UniversityChongqing400715China Chongqing Fishery Sciences Research Institute Chongqing401120China Guizhou Fisheries Research Institute Guiyang550025China College of Fisheries Huazhong Agricultural UniversityWuhan430072China Hubei Fisheries Science Research Institute Wuhan430070China Shaanxi Fisheries Research Institute Xi’an710086China Innovation Academy for Precision Measurement Science and Technology Chinese Academy of SciencesWuhan430077China Nanjing Institute of Geography and Limnology Chinese Academy of SciencesNanjing210008China Central South Inventory and Planning Institute of State Forestry and Grassland Administration Changsha410014China

The Yangtze River is the mother river of *** promote the aquatic ecosystem protection of the great river,the Project of Yangtze Fisheries Resources and Environment Investigation(2017-2021)supported by the Ministry of Agriculture and Rural Affairs,*** carried out by 24 institutes and universities that located in the Yangtze River basin surveys the status of(1)fish species composition and spatial distribution,(2)current fish abundance,(3)endangered fishes,(4)Yangtze finless porpoise,(5)aquatic eco-environments,(6)water-level fluctuation areas,(7)capture fisheries and recreational fisheries of the Yangtze River mainstream and 10 of its main tributaries,including Yalong River,Heng River,Min River(including Dadu River),Chishui River,Tuo River,Jialing River,Wu River,Han River,Dongting Lake and Poyang *** results showed that there were 443 fish species(belonging to 163 genus,37 families,and 18 orders)before 2017,but only 323 fish species(including 15 new recorded exotic species)were recorded in the project of *** them,Cyprinus carpio,Carassius auratus,Hypophthalmichthys molitrix,Pelteobagrus fulvidraco,Coilia brachygnathus,Silurus asotus,Saurogobio dabryi,Ctenopharyngodon idellus,Pelteobagrus nitidus,Hemiculter leucisculus,Siniperca chuatsi,Coreius heterodon,Culter alburnus,Parabramis pekinensis,and Aristichthys nobilis were the dominant species across the whole Yangtze River *** is estimated that there were 886 million individuals weighing 124.8 million kg,merely equivalent to 27.3%of the resources in 1950s,30.9%of the resources in 1960s,or 58.7%of the resources in *** the new list of protected fishes that recorded in the Yangtze River system,only 15 of 29 were collected in this project of *** gladius has been affirmed to be Extinct by International Union for Conservation of Nature(IUCN).The wild individuals of Tenualosa reevesii and Luciobrama macrocephalus have disappeared for many years and maybe have been extinct

关键词： Fishes Yangtze finless porpoise Resources Aquatic ecosystem Fisheries Background investigation Yangtze river system

基于OpenGL针织袜品三维仿真系统的研究

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

针织工业 2013年第9期 12-15页

作者：陈勇铭谢梅娣东华大学纺织学院上海201620

建立针织袜品三维模型是开发针织袜品三维CAD系统的关键步骤之一。本文根据针织袜品结构,在OpenGL中采用Bezier(贝塞尔)曲面构造的方法建立了针织袜品三维模型,并实现了袜筒部位上的提花组织贴图及袜品三维模型的任意旋转,获得了外观相... 详细信息

建立针织袜品三维模型是开发针织袜品三维CAD系统的关键步骤之一。本文根据针织袜品结构,在OpenGL中采用Bezier(贝塞尔)曲面构造的方法建立了针织袜品三维模型,并实现了袜筒部位上的提花组织贴图及袜品三维模型的任意旋转,获得了外观相似度高、具有良好表面仿真效果、可全方位观察的针织袜品三维模型,为其三维仿真系统的开发提供了参考。

关键词：针织袜品 OpenGL 三维建模仿真模拟贝塞尔曲面

改造柴油加氢精制装置为催化裂化装置提供优质原料

在线全文

学校读者我要写书评

暂无评论

炼油技术与工程 2005年第5期35卷 5-7页

作者：向琼谢承志程咏明中国石化股份有限公司武汉分公司湖北省武汉市430082

武汉分公司采用热高分流程对柴油加氢装置进行了技术改造,改造后加氢装置具有切换处理柴油和蜡油的能力,改善了焦化蜡油的性质,为催化裂化装置提供了优质的原料。

关键词：催化裂化装置加氢精制装置优质原料柴油加氢装置技术改造焦化蜡油

CNC铣刀磨损状态的大数据分析与预测方法研究

在线全文

学校读者我要写书评

暂无评论

机床与液压 2020年第21期48卷 105-110页

作者：谢马军吴永明广东工业大学机电工程学院广东广州510006

为在铣切加工过程中预测铣刀的磨损状态以及时发现并更换将要磨钝的铣刀,以保障产品质量,运用传感器采集CNC铣床在加工过程中铣床及铣刀的振动信号数据,应用大数据方法研究CNC铣刀磨损状态的分析和预测方法。为保证铣刀磨损状态的识别... 详细信息

为在铣切加工过程中预测铣刀的磨损状态以及时发现并更换将要磨钝的铣刀,以保障产品质量,运用传感器采集CNC铣床在加工过程中铣床及铣刀的振动信号数据,应用大数据方法研究CNC铣刀磨损状态的分析和预测方法。为保证铣刀磨损状态的识别精度、识别稳定性和分析模型的鲁棒性,采用小波包分解理论对铣床x、y、z三向振动信号数据进行降噪处理,提取时域特征和能量特征,筛选出与磨损状态相关性较大的34个特征。应用XGBoost算法建立铣刀磨损状态的数据分析模型,使用宏平均值评估模型性能,结合SMOTE技术对特征向量进行过采样,使各磨损状态类别样本均衡。借助公开的球头铣刀加工数据集对所提方法进行验证,实验结果表明:利用XGBoost算法能正确分析铣刀磨损状态的数据,能识别出铣刀磨损预警阶段。XGBoost算法的预测精度高、稳定性好、泛化能力强,易应用于工业大数据领域。

关键词：铣刀磨损状态振动大数据分析预测方法 XGBoost算法

在线全文

学校读者我要写书评

暂无评论

基于变采样长度傅里叶变换的白光干涉仪解调

光学学报 2014年第13期34卷 90-93页

作者：谢杰辉王付印胡正良胡永明国防科技大学光电科学与工程学院湖南长沙410073

基于傅里叶变换的非本征光纤法布里-珀罗干涉仪（EFPI）的解调方法，对解调白光干涉的EFPI具有解调精度高，动态范围大，且可实现腔长的绝对测量等优点。然而，该方法的动态范围和解调精度分别受限于采样导致的非线性谱分布以及傅里叶... 详细信息

基于傅里叶变换的非本征光纤法布里-珀罗干涉仪（EFPI）的解调方法，对解调白光干涉的EFPI具有解调精度高，动态范围大，且可实现腔长的绝对测量等优点。然而，该方法的动态范围和解调精度分别受限于采样导致的非线性谱分布以及傅里叶变换的栅栏效应。分别采用三次样条插值和改进的傅里叶变换来消除光谱的啁啾特性和提高解调精度。仿真和实验证明该算法的解凋精度提高了70倍。

关键词：传感器高精度新型算法非本征光纤法布里-珀罗干涉仪

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

谐振型光纤陀螺克尔效应误差消除方法研究

光子学报 2005年第9期34卷 1320-1323页

作者：姚琼胡永明宋章启谢元平国防科学技术大学光电科学与工程学院长沙410073

对采用方波频率调制数字闭环谐振型光纤陀螺中克尔效应的影响进行了深入的理论分析.分析表明,由克尔效应引起的陀螺误差不仅与光纤环内两相反方向光束的光强差有关,而且还依赖于两路光波频率调制的调制幅度.通过适当调节两光束的频率调... 详细信息

对采用方波频率调制数字闭环谐振型光纤陀螺中克尔效应的影响进行了深入的理论分析.分析表明,由克尔效应引起的陀螺误差不仅与光纤环内两相反方向光束的光强差有关,而且还依赖于两路光波频率调制的调制幅度.通过适当调节两光束的频率调制幅度,可有效地实现克尔效应误差的消除.这种基于方波频率调制的克尔效应误差消除方法利用了方波调制的特点,通过调节调制幅度实现误差消除,无需额外光学元件,对强度调制器调制频率要求低,是数字谐振型光纤陀螺系统中消除克尔效应误差的有效方法.

关键词：谐振型光纤陀螺克尔效应误差消除方渡频率调制

在线全文

学校读者我要写书评

暂无评论

开心散调控自噬防治阿尔茨海默症研究进展

辽宁中医药大学学报 2024年第2期26卷 206-210页

作者：刘兴源史宝瑞袁常斌何晓明程美佳刘勇明谢思梦鞠业涛王欣欣杨关林闵冬雨王晓彤辽宁中医药大学辽宁沈阳110847 辽宁中医药大学附属医院辽宁沈阳110032

阿尔茨海默症(alzheimer disease,AD)是目前常见的一种神经退行性疾病,该病的发病率正处在一个持续上升的阶段,由于其发病机制复杂,因此对该病的治疗方案也有很多。随着对自噬研究的深入,发现在一定程度上调节自噬可以对AD产生影响并且... 详细信息

阿尔茨海默症(alzheimer disease,AD)是目前常见的一种神经退行性疾病,该病的发病率正处在一个持续上升的阶段,由于其发病机制复杂,因此对该病的治疗方案也有很多。随着对自噬研究的深入,发现在一定程度上调节自噬可以对AD产生影响并且一定程度上可以改善AD症状。开心散由唐代孙思邈创立,由人参、远志、茯苓、石菖蒲4味药组成,该方补泻兼施,以补为主,主要治疗心悸怔忡、失眠健忘等疾病。随着现代医学的发展,以及对其药物成分的深入研究,发现其在改善学习记忆方面具有显著效果,同时发现了开心散的药物成分可以通过影响自噬相关蛋白对AD进行调节。其中腺苷酸活化蛋白激酶(AMPK)自噬通路是这4味药发挥作用的主要通路。因此,该文通过查阅中外文献并进行整理分析,对开心散调控自噬防治AD做出综述,为阿尔茨海默症的临床治疗提供新思路。

关键词：开心散自噬阿尔茨海默症腺苷酸活化蛋白激酶 β-淀粉样蛋白

维普期刊数据库博看期刊

EpCAM(EpEx/Ep-ICD) expression and clinical correlation:potential diagnostic biomarker of pancreatic cancer

在线全文

学校读者我要写书评

暂无评论

EpCAM(EpEx/Ep-ICD) expression and clinical correlation:poten...