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Determination of the load bearing capacity of pre-stressed expandable props for ground support in underground mines

矿业科学技术学报:英文版 2023年第8期33卷 977-990页

作者： Kunmeng li Kaiyuan Jiang Yuanhui li Xin Wang Kai liu Shuai Xu key laboratory of ministry of education on Safe Mining of Deep Metal Mines School of Resources and Civil EngineeringNortheastern UniversityShenyang 110819China key laboratory of liaoning Province on Deep Engineering and Intelligent Technology School of Resources and Civil EngineeringNortheastern UniversityShenyang 110819China china-Canada Centre of Deep Mining Innovation Key Laboratory of Ministry of Education on Safe Mining of Deep Metal MinesSchool of Resources and Civil EngineeringNortheastern UniversityShenyang 110819China Department of Engineering science University of OxfordOxford OX13PJUnited Kingdom

This paper aims to determine the load bearing capacity of pre-stressed expandable props with different geometries and load eccentricities for flexible support in underground mining or *** is deduced that the expandable device could have much higher strength(>89 MPa)by laboratory tests,and the load bearing capacity of the expandable prop may depend on the stability of the supporting steel pipe structure.A good agreement was found between the laboratory test and numerical results in terms of the load bearing capacity and the final macro-bending failure pattern for expandable props with heights of 1.5 and 2.7 m,and the theoretical calculation for the strength of traditional steel structures is not directly suitable for the expandable ***,additional numerical simulations were performed for the expandable props with different normalized slenderness ratiosλ_(n)and loading eccentric distances *** variation of stability coefficient of the expandable prop is in line with the Perry-Robertson equation and its correlation coefficients are fitted as a of 0.979 and b of *** estimating the load bearing capacity of the expandable props,the strength equation for traditional steel structures is improved by introducing a bending magnification factor and by modifying the normalized slenderness ratio to a converted slenderness *** on the underground field monitoring for the strength of expandable props with different heights,the empirical eccentric distances were back calculated,and a safety factor is introduced to obtain the designed strength of the expandable *** addition,a four-step design procedure is proposed for the expandable prop.

关键词： Pillar stability Load bearing capacity Expandable prop Slenderness ratio Eccentric distance

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Bluetooth Low Energy Device Identification Based on link Layer Broadcast Packet Fingerprinting

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Tsinghua science and Technology 2023年第5期28卷 862-872页

作者： Jinghui Zhang Xinyang li Junhe li Qiangsheng Dai Zhen ling Ming Yang School of Computer science and Engineering Southeast UniversityNanjing 211189China School of Cyber science and Engineering Southeast UniversityNanjing 211189China Research Institute State Grid Jiangsu Electric Power Company Ltd.Nanjing 210024China

With the rapid development of the Internet of Things(IoT),wireless technology has become an indispensable part of modern computing platforms and embedded *** device fingerprint identification is deemed as a promising solution towards enhancing the security of device access authentication and communication process in the IoT ***,the extraction of features from the network layer and its upper layers often confront restrictions from specific devices:the association with a certain wireless network and the access to the plaintext of the ***,Bluetooth Low Energy(BLE)packets have been encrypted above the link layer,which makes those features difficult to *** tackle these problems,we introduce a novel method to identify BLE devices based on the fingerprint features in the data link ***,the BLE packets are collected through a receiver based on software-defined radio ***,fields that reflect device differences in BLE broadcast packets are extracted through traffic ***,a MultiLayer Perceptron(MLP)model is employed to recognize the category of BLE *** experimental result on a dataset with 15 types of BLE devices shows that the identification accuracy of the proposed method can reach 99.8%,which accomplishes better performance over previous work.

关键词： link layer fingerprint software-defined radio Bluetooth Low Energy(BLE)

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氧化石墨烯对天然水硬性石灰水化及力学性能的影响

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硅酸盐通报 2024年第7期43卷 2640-2648页

作者：张彪刘泓宇齐南王芬朱建锋李立马涛罗宏杰施佩陕西科技大学材料科学与工程学院文物保护科学与技术学院地下文物保护材料与技术教育部重点实验室西安710021 陕西省文物保护研究院砖石质文物保护国家文物局重点科研基地西安710075 上海大学文化遗产与信息管理学院硅酸盐质文物保护教育部重点实验室上海200444

石质文物是一类重要的文化遗产,然而裂隙会导致其产生失稳、渗水、风化等病害,因此,开发一种合适的灌浆材料用于石质文物裂隙修复具有重要意义。本文将氧化石墨烯(GO)掺入天然水硬性石灰(NHL2)制备灌浆材料,采用SEM、TG、XRD和FT-IR等... 详细信息

石质文物是一类重要的文化遗产,然而裂隙会导致其产生失稳、渗水、风化等病害,因此,开发一种合适的灌浆材料用于石质文物裂隙修复具有重要意义。本文将氧化石墨烯(GO)掺入天然水硬性石灰(NHL2)制备灌浆材料,采用SEM、TG、XRD和FT-IR等测试研究了GO掺量对NHL2水化进程及水化产物的影响,通过力学性能测试和模拟灌浆试验评价了该材料用于石质文物灌浆加固的可行性。结果表明:添加GO可加速NHL2的水化进程,促进规整致密的花状聚集态水化产物的形成;当GO掺量为0.05%(质量分数)时,试样的水化产物含量最多,力学性能最好,28 d抗压强度和抗折强度分别达2.83和1.63 MPa,相比空白试样分别提高了19.91%和23.40%。此外,灌浆材料与砂岩之间具有优异的黏结强度,两者界面结合紧密,兼容性良好。本研究为石质文物的裂隙灌浆加固提供了参考。

关键词：天然水硬性石灰氧化石墨烯水化产物微观结构兼容性灌浆加固

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郁金提取物对山葵墨入菌(Phoma wasabiae)的抑菌活性研究

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四川大学学报（自然科学版） 2008年第5期45卷 1235-1238页

作者：刘海华尉研崔佳黄译影王立洪刘世贵龙章富四川大学生命科学学院生物资源与生态环境教育部重点实验室成都610064

应用生长速率法测定了用清水、95%乙醇溶液提取郁金获得的水提物、醇提物对山葵墨入菌的抑菌活性,结果表明在供试浓度为1.0×10-3g/mL时,郁金95%乙醇热搅拌提取物对山葵墨入菌的菌丝生长表现出明显的抑制作用,其抑制率为67.08%;将其95%... 详细信息

应用生长速率法测定了用清水、95%乙醇溶液提取郁金获得的水提物、醇提物对山葵墨入菌的抑菌活性,结果表明在供试浓度为1.0×10-3g/mL时,郁金95%乙醇热搅拌提取物对山葵墨入菌的菌丝生长表现出明显的抑制作用,其抑制率为67.08%;将其95%乙醇粗提物依次用正己烷、乙酸乙酯、甲醇萃取后测定其生物活性,结果表明郁金提取物的抑菌活性物质主要在正己烷萃取物中,在供试浓度为1.0×10-3g/mL时,对山葵墨入菌的抑菌率达到79.70%,其EC50为0.3299×10-3g/mL,在供试浓度为10.0×10-3g/mL时,郁金正己烷萃取物对墨入菌孢子萌发抑制率为97.2%.郁金正己烷萃取物对常见的植物病原真菌:小麦赤霉菌、油菜菌核菌、番茄灰霉菌均有较高的抑菌率,其EC50分别为0.2517×10-3g/mL、0.2809×10-3g/mL、0.1749×10-3g/mL.

关键词：郁金山葵墨入菌抑菌活性

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Optimizing Photovoltaic Performance by Kinetic Quenching of Layered Heterojunctions

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Chinese Journal of Polymer science 2022年第1期40卷 29-37页

作者： li-Feng Xu Zhan-Wen Xu Jia-Ping lin li-Quan Wang Shanghai key laboratory of Advanced Polymeric Materials Key Laboratory for Ultrafine Materials of Ministry of EducationSchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China

The mixing morphology control plays a crucial role in photovoltaic power generation,yet this specific effect on device performances remains ***,we employed computational approaches to delineate the photovoltaic properties of layered heterojunction polymer solar cells with tunable mixing ***-step quench and two-step quench strategies were proposed to adjust the mixing morphology by thermodynamic and kinetic *** computation for the one-step quench revealed that modulating interfacial widths and interfacial roughness could significantly promote the photovoltaic performance of layered heterojunction polymer solar *** two-step quench can provide a buffer at a lower temperature before the kinetic quenching,leading to the formation of small-length-scale islands connected to the interface and a further increase in photovoltaic *** discoveries are supported by recent experimental evidence and are anticipated to guide the design of photovoltaic materials with optimal performance.

关键词： Dissipative particle dynamics Drift-diffusion model Polymer solar cells Quench

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Oxygen vacancy self-doped single crystal-like TiO_(2) nanotube arrays for efficient light-driven methane non-oxidative coupling

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先进陶瓷(英文) 2023年第8期12卷 1577-1592页

作者： Jinbo Xue Jinyu li Zhe Sun Huimin li Huan Chang Xuguang liu Husheng Jia Qi li Qianqian Shen key laboratory of Interface science and Engineering in Advanced Materials Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024China College of Materials science and Engineering Taiyuan University of TechnologyTaiyuan 030024China Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Taiyuan 030032China School of Materials science and Engineering Southwest Jiaotong UniversityChengdu 610031China

Photocatalytic non-oxidative coupling of methane(PNOCM)is a mild and cost-effective method for the production of multicarbon ***,the separation of photogenerated charges and activation of methane(CH4)are the main challenges for this ***,single crystal-like TiO_(2) nanotubes(VO-p-TNTs)with oxygen vacancies(VO)and preferential orientation were prepared and applied to *** results demonstrate that the significantly enhanced photocatalytic performance is mainly related to the strong synergistic effect between preferential orientation and *** preferential orientation of VO-p-TNT along the[001]direction reduces the formation of complex centers at grain boundaries as the form of interfacial states and potential barriers,which improves the separation and transport of photogenerated ***,VO provides abundant coordination unsaturated sites for CH4 chemisorption and also acts as electron traps to hinder the recombination of electrons and holes,establishing an effective electron transfer channel between the adsorbed CH4 molecule and photocatalyst,thus weakening the C–H *** addition,the introduction of VO broadens the light absorption *** a result,VO-p-TNT exhibits excellent PNOCM performance and provides new insights into catalyst design for CH4 conversion.

关键词： TiO_(2)nanotubes(TNTs) oxygen vacancies(VO) preferential orientation photocatalytic non-oxidative coupling of methane(PNOCM)

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采矿爆破振动主频率在岩溶区衰减规律现场试验研究

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中国岩溶 2024年第2期43卷 454-462页

作者：唐灵明黄翔李红明李佳明曹贤发陈学军卢丽霞广西岩土力学与工程重点实验室广西桂林541004 广西师范大学广西桂林541004 广西交科集团有限公司广西南宁530007 中国有色金属长沙勘察设计研究院有限公司珠海分公司广东珠海519020

为减小岩溶区采矿爆破施工中振动产生的地表塌陷灾害影响,文章根据岩溶区矿山爆破振动现场实测数据,采用傅里叶变换及回归分析方法,对比分析塌陷区与非塌陷区爆破振动主频率的衰减规律,以讨论岩土体性质、震中距及爆破药量对爆破振动主... 详细信息

为减小岩溶区采矿爆破施工中振动产生的地表塌陷灾害影响,文章根据岩溶区矿山爆破振动现场实测数据,采用傅里叶变换及回归分析方法,对比分析塌陷区与非塌陷区爆破振动主频率的衰减规律,以讨论岩土体性质、震中距及爆破药量对爆破振动主频率特性的影响。结果表明:岩土体性质对爆破振动主频率存在较大影响,表现为结构愈松散、孔隙度愈大、密实度愈小,其爆破振动主频率和振动能量衰减得愈快;同一次爆破中,在塌陷区外及塌陷回填区内,所获得的振动主频率随其震中距的增加而呈减小趋势,而在塌陷区内,并非严格衰减,出现波动现象,略有上升趋势;在塌陷区与非塌陷区,爆破振动主频率随着震中距和药量的增加而减小;在同一振动荷载作用下,爆破振动主频率在塌陷区的衰减速度明显大于非塌陷区,且爆破药量在塌陷区内对爆破振动主频率衰减速度的影响更大。

关键词：岩溶区爆破振动主频率传播速度傅里叶变换衰减规律

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Population Attributable Fractions for Modifiable Factors of Longevity and Healthy Longevity Among the Late-Elderly Aged 75 Years or Older—china,1998-2018

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china CDC weekly 2023年第2期5卷 25-30,I0001-I0003页

作者： Jinhui Zhou Xiang gao Yuan Wei Chen Chen Jun Wang Zhenwei Zhang Xinwei li lihong Ye Jiaming Ye Sixin liu Xiaochang Zhang Feng Zhao Juan Zhang Virginia Byers Kraus Yuebin Lyu Chen Mao Xiaoming Shi china CDC key laboratory of Environment and Population Health National Institute of Environmental HealthChinese Center for Disease Control and PreventionBeijingChina Department of Nutrition and Food Hygiene School of Public HealthInstitute of NutritionFudan UniversityShanghaiChina Department of Epidemiology and Biostatistics School of Public HealthJilin UniversityChangchunJilinChina School of Population Medicine and Public Health Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijingChina Department of Epidemiology School of Public HealthSouthern Medical UniversityGuangzhouGuangdongChina Division of Non-communicable Disease and Aging Health Management Chinese Center for Disease Control and PreventionBeijingChina Duke Molecular Physiology Institute and Division of Rheumatology Department of MedicineDuke University School of MedicineDurhamNorth CarolinaUSA Center for Global Health School of Public HealthNanjing Medical UniversityNanjingJiangsuChina

Summary What is already known about this topic?limited evidence on healthy longevity was provided in the world,and no studies investigated the fractions of healthy longevity attributed to modifiable *** is added by this report?Incidences of longevity and healthy longevity in china are *** reveals that the total weighted population attributable fractions for lifestyles and all modifiable factors were 32.8% and 83.7% for longevity,respectively,and 30.4% and 73.4% for healthy longevity,*** are the implications for public health practice?china has a high potential for longevity and healthy *** may be targeted at education and residence in early life as well as healthy lifestyles,disease prevention,and functional optimization in late life.

关键词： prevention attributed education

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辽东湾海水中金属基纳米颗粒的赋存水平与环境风险

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中国科学：化学 2024年第6期54卷 950-960页

作者：李欣雨李国新王昊宋一乐王建军赵雅婷王储刘霞孙雪梅赵建中国海洋大学近海环境污染控制研究所海洋环境与生态教育部重点实验室青岛266100 青岛海洋科技中心海洋生态与环境科学功能实验室青岛266237 中国水产科学研究院黄海水产研究所青岛266071

纳米科技的迅速发展使得纳米材料,特别是金属基纳米颗粒(NPs)的环境污染问题备受关注.海洋(特别是近海海湾)是金属基NPs重要的“汇”,然而环境浓度的缺失阻碍了金属基NPs在海洋环境中的风险评估.本文采用单粒子电感耦合等离子体质谱法(s... 详细信息

纳米科技的迅速发展使得纳米材料,特别是金属基纳米颗粒(NPs)的环境污染问题备受关注.海洋(特别是近海海湾)是金属基NPs重要的“汇”,然而环境浓度的缺失阻碍了金属基NPs在海洋环境中的风险评估.本文采用单粒子电感耦合等离子体质谱法(sp-ICP-MS)探究了辽东湾海水中Ag、Ti、Cu和Zn基NPs的赋存水平及空间分布,并基于金属基NPs对海洋生物的预测无效应浓度(PNECs),使用风险表征比(RCR)对4种金属基NPs在辽东湾的环境风险进行了评估.结果表明,使用sp-ICP-MS以稀释法(Ti、Cu和Zn基NPs)和浊点萃取法(Ag基NPs)可以实现对4种金属基NPs的准确定量,回收率分别为97.1%、96.4%、95.3%和96.7%.空间分布表明,辽东湾中Ti基NPs的平均浓度最高(3.98×10^(8)个/L),其次为Ag、Cu和Zn基NPs;Ag基NPs在辽东湾西部沿岸浓度最高(6.81×10^(7)个/L),其他3种NPs则在北部沿岸大凌河口浓度最高,分别为1.87×10^(9)(Ti基NPs)、5.86×10^(7)(Ag基NPs)和2.12×10^(7)个/L(Zn基NPs).4种金属基NPs中,Ag基NPs的环境风险最高,在所有调查的16个站位中,有15个站位为“中风险”;4种NPs的总体环境风险(RCRtotal)在所有调查站位均处于“中风险”,且Ag基NPs对总体环境风险的贡献最大(>50%).本研究将有助于科学认识辽东湾海域金属基NPs的赋存水平和客观评估其环境风险.

关键词： sp-ICP-MS 金属基纳米颗粒赋存水平辽东湾环境风险

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东北红豆杉细胞GGPPS基因cDNA的克隆

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黑龙江大学自然科学学报 2012年第4期29卷 536-540页

作者：王歆肖野刘丹李秀凉赵凯黑龙江大学生命科学学院微生物黑龙江省高校重点实验室哈尔滨150080 黑龙江大学农业微生物技术教育部工程研究中心哈尔滨150500

牻牛儿基牻牛儿基焦磷酸合成酶是红豆杉细胞紫杉醇生物合成途径中的关键酶。试验采用RT-PCR技术从东北红豆杉中克隆GGPPS基因片段,将GGPPS基因片段与pMD20-Tvector连接,转化*** DH5α,对阳性克隆进行序列测定。生物信息学分析结果表明,... 详细信息

牻牛儿基牻牛儿基焦磷酸合成酶是红豆杉细胞紫杉醇生物合成途径中的关键酶。试验采用RT-PCR技术从东北红豆杉中克隆GGPPS基因片段,将GGPPS基因片段与pMD20-Tvector连接,转化*** DH5α,对阳性克隆进行序列测定。生物信息学分析结果表明,获得GGPPS基因片段长度为371 bp,与GenBank中收录的GGPPS同源性达到99%。为从内生真菌紫杉醇生物合成途径中克隆关键酶基因和高产紫杉醇基因工程菌株的构建提供了借鉴。

关键词：红豆杉紫杉醇牻牛儿基牻牛儿基焦磷酸合成酶

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