检索结果-南通市图书馆

新型炭材料 2000年第4期15卷 39-43页

作者：陈小华王健雄邓福铭李宏健王淼卢筱楠彭景翠李文铸浙江大学物理系浙江杭州310027 湖南大学应用物理系湖南长沙410082

利用化学镀方法在纳米级碳管表面化学镀镍 ,得到新一类一维纳米复合材料。研究了工艺条件对碳纳米管化学镀镍的影响 ,并指出了要得到较好镀层的主要因素。

关键词：碳纳米管化学镀一维纳米复合材料镀层

Failure mechanism and safety control technology of a composite strata roadway in deep and soft rock masses:a case study

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第7期21卷 2427-2444页

作者： ZHAO Chengwei ZHOU Hui SUN Xiaoming ZHANG Yong miao Chengyu wang jian State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory for GeoMechanics and Deep Underground Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing 100083China

The construction of coal mines often encounters deep composite soft rock roadways,which is characterized by significant deformation and poor *** deeply study the failure mechanism and large deformation challenges of a composite strata roadway in deep and soft rock masses,a numerical model of 3DEC tetrahedral blocks was established based on the method of rock quality designation(RQD).The results showed that original support cannot prevent asymmetric failure and large deformation due to the adverse geological environment and unsuitable support *** to the failure characteristics,a coupling support of“NPR bolt/cable+mesh+shotcrete+steel pipe”was proposed to control the stability of the surrounding *** excellent mechanical properties of large deformation(approximately 400 mm)and high constant resistance force(bolt with 180 k N;cable with 350 k N)were evaluated by the tensile *** numerical results showed that the maximum deformation was minimized to 243 mm,and the bearing capacity of the surrounding rock of the roadway was *** field test results showed that the maximum deformation of the surrounding rock was 210 mm,and the forces of the NPR bolt and cable were stable at approximately 180 k N and 350 k N,*** demonstrated the effectiveness of the coupling support with the NPR bolt and cable,which could be a guiding significance for the safety control of large deformation and failure in deep composite soft rock roadways.

关键词： 3DEC Composite strata roadway Soft rock NPR bolt and cable Asymmetric large deformation

Multiphasic characterization of a plant growth promoting bacterial strain, Burkholderia sp.7016 and its effect on tomato growth in the field

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2015年第9期14卷 1855-1863页

作者： GAO miao ZHOU jian-jiao wang En-tao CHEN Qian XU Jing SUN jian-guang Key Laboratory of Microbial Resources Ministry of Agriculture/Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural Sciences Departmento de Microbiología Escuela Nacional de Ciencias BiológicasInstituto Polytécnico National

Aiming at searching for plant growth promoting rhizobacteria (PGPR), a bacterium strain coded as 7016 was isolated from soybean rhizosphere and was characterized in the present study. It was identiifed as Burkholderia sp. based on 16S rDNA sequence analysis, as wel as phenotypic and biochemical characterizations. This bacterium presented nitrogenase activity, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity and phosphate solubilizing ability;inhibited the growth of Sclerotinia sclerotiorum, Gibberel a zeae and Verticil ium dahliae;and produced smal quantities of indole acetic acid (IAA). In green house experiments, signiifcant increases in shoot height and weight, root length and weight, and stem diameter were observed on tomato plants in 30 d after inoculation with strain 7016. Result of 16S rDNA PCR-DGGE showed that 7016 survived in the rhizosphere of tomato seedlings. In the ifeld experiments, Burkholderia sp. 7016 enhanced the tomato yield and signiifcantly promoted activities of soil urease, phosphatase, sucrase, and catalase. Al these results demonstrated Burkholderia sp. 7016 as a valuable PGPR and a candidate of biofertilizer.

关键词： PGPR Burkholderia sp. multiphasic characterization promoting growth biofertilizer

Al_2O_3 coated LiCoO_2 as cathode for high-capacity and long-cycling Li-ion batteries

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2018年第12期29卷 1768-1772页

作者： Zelang jian Wentao wang Maoyu wang Yan wang Nick AuYeung miao Liu Zhenxing Feng School of Chemical Biologicaland Environmental EngineeringOregon State University State Key Laboratory of Advanced Technology for Materials Synthesis and Processing School of Materials Science and EngineeringWuhan University of Technology Institute of Physics Chinese Academy of Sciences

Lithium-ion batteries(LIBs) as energy storage devices play an important role in all aspects of our life. The increasing energy demand of the society requires LIBs with higher energy density and better performance. We here develop a new and easy-to-scaleup sol-gel method to coat a surface protection layer on commercial LiCoO2cathode. We demonstrate that a proper thickness can improve the cycling life with a higher cut-off potential(4.5 V), larger energy capacity(180 mAh/g at 0.5 C) and better energy density(35% more compared to non-coated LiCoO2). The mechanism of the protection layer is also revealed by a combination of electron microscopy and synchrotron X-ray spectroscopy.

关键词： Lithium-ion batteries Al_2O_3 coating High-capacity Long-cycling X-ray absorption spectroscopy

融合BiLSTM与CNN的推特黑灰产分类模型

在线全文

学校读者我要写书评

暂无评论

计算机工程与应用 2025年第1期61卷 186-195页

作者：朱恩德王威高见中国人民公安大学信息网络安全学院北京100038

当前推特等国外社交平台,已成为从事网络黑灰产犯罪不可或缺的工具,对推特上黑灰产账号进行发现、检测和分类对于打击网络犯罪、维护社会稳定具有重大意义。现有的推文分类模型双向长短时记忆网络(bi-directional long short-term memor... 详细信息

当前推特等国外社交平台,已成为从事网络黑灰产犯罪不可或缺的工具,对推特上黑灰产账号进行发现、检测和分类对于打击网络犯罪、维护社会稳定具有重大意义。现有的推文分类模型双向长短时记忆网络(bi-directional long short-term memory,BiLSTM)可以学习推文的上下文信息,却无法学习局部关键信息,卷积神经网络(convolution neural network,CNN)模型可以学习推文的局部关键信息,却无法学习推文的上下文信息。结合BiLSTM与CNN两种模型的优势,提出了BiLSTM-CNN推文分类模型,该模型将推文进行向量化后,输入BiLSTM模型学习推文的上下文信息,再在BiLSTM模型后引入CNN层,进行局部特征的提取,最后使用全连接层将经过池化的特征连接在一起,并应用softmax函数进行四分类。模型在自主构建的中文推特黑灰产推文数据集上进行实验,并使用TextCNN、TextRNN、TextRCNN三种分类模型作为对比实验,实验结果显示,所提的BiLSTM-CNN推文分类模型在对四类推文进行分类的宏准确率为98.32%,明显高于TextCNN、TextRNN和TextRCNN三种模型的准确率。

关键词：文本分类双向长短期记忆网络(BiLSTM) 卷积神经网络(CNN) 黑灰产推特

Coupling interface constructions of FeOOH/NiCo_(2)S_(4)by microwave-assisted method for efficient oxygen evolution reaction

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2023年第6期42卷 1847-1857页

作者： Ming-Liang Guo Zhi-Yu Wu miao-miao Zhang Zi-jian Huang Ke-Xi Zhang Bing-Rong wang Jin-Chun Tu State Key Laboratory of Marine Resource Utilization in the South China Sea College of Materials Science and EngineeringHainan UniversityHaikou570228China School of Science Hainan UniversityHaikou570228China

The oxygen evolution reaction(OER) with slow kinetics is the rate-limiting step of electrochemical water splitting.A reasonable construction of interface nanostructures is the key to improving the OER efficiency and durability of non-noble metal *** this study,a FeOOH/NiCo_(2)S_(4) core-shell nanorod array with abundant heterogeneous interfaces and high density of active sites was successfully prepared by a microwave-as sis ted *** research and theoretical calculations show that the abundant strong coupling Ni/Co-S-Fe interface helps in adjusting the electronic structure of the material surface,optimizing the adsorption energy of the intermediate,and realizing an efficient catalytic *** as-synthesized FeOOH/NiCo_(2)S_(4)/NF composite electrode exhibited lower overpotential(198 mV) and Tafel slope(62 mV·dec^(-1)) at a current density of 10 mA·cm^(-2)and excellent stability(approximately 100% retention after100 h) than the NiCo_(2)S_(4)/nickel foam(NF).In conclusion,constructing heterojunctions with complementary active materials is an effective strategy to design efficient and robust OER electrocatalysts.

关键词： Transition metal sulfides FeOOH Interface structure Adsorption energy Oxygen evolution

Bearing-only Visual SLAM for Small Unmanned Aerial Vehicles in GPS-denied Environments

在线全文

学校读者我要写书评

暂无评论

International Journal of Automation and computing 2013年第5期10卷 387-396页

作者： Chao-Lei wang Tian-miao wang jian-Hong Liang Yi-Cheng Zhang Yi Zhou Robotics Institute Beijing University of Aeronautics and Astronautics

This paper presents a hierarchical simultaneous localization and mapping（SLAM） system for a small unmanned aerial vehicle（UAV） using the output of an inertial measurement unit（IMU） and the bearing-only observations from an onboard monocular camera.A homography based approach is used to calculate the motion of the vehicle in 6 degrees of freedom by image feature *** visual measurement is fused with the inertial outputs by an indirect extended Kalman filter（EKF） for attitude and velocity ***,another EKF is employed to estimate the position of the vehicle and the locations of the features in the *** simulations and experiments are carried out to test the performance of the proposed *** result of the comparison with the referential global positioning system/inertial navigation system（GPS/INS） navigation indicates that the proposed SLAM can provide reliable and stable state estimation for small UAVs in GPS-denied environments.

关键词： Visual simultaneous localization and mapping(SLAM) bearing-only observation inertial measurement unit small unmanned aerial vehicles(UAVs) GPS-denied environment

Discrimination conditions and process of water-resistant key strata

在线全文

学校读者我要写书评

暂无评论

Mining Science and Technology 2010年第2期20卷 224-229页

作者： wang, Lianguo miao, Xiexing WU, Yu SUN, jian YANG, Hongbo state key laboratory of geomechanics & deep underground engineering china university of mining & technologyxuzhou 221008china

Water-preservation mining is one of the most important parts of the ‘Green Mining' technology system,which can realize the effective regulation of groundwater resources by controlling strata movement,changing passive prevention and governance of water disasters to active conservation and utilization of groundwater resources and thus obtaining coal and water simultaneously in *** concept of water-resistant key strata further enriches the content of the key stratum theory and provides a theoretical basis for water-preservation *** order to realize the idea of water-resistant key strata as a guideline in the design of water-preservation mining and engineering applications,the conditions for discrimination in the process of water-resistant key strata,we have presented a mechanical model,as well as its corresponding computer program,based on a large number of theoretical analyses and field measurements,as well as on a comprehensive consideration of the position,structural stability and seepage stability of key *** engineering applications indicate that this discrimination method and its corresponding computer program on water-resistant key strata are accurate and reliable and can satisfy the actual design needs of water-preservation mining and thus have instructional importance for water-preservation mining in mining areas lacking water.

关键词： water-resistant key stratum water-preservation mining structural stability seepage stability

Aggregation Behavior and Structure of Associated Polyacrylamide Hydrophobically Modified with 2-Phenoxylethylacrylate

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2009年第6期25卷 957-962页

作者： DAI Yu-hua WU Fei-peng LI miao-zhen wang Er-jian Department of Materials Science and Engineering Beijing Institute of Petrochemical Technology Beijing 102617 P. R. China Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100101 P. R. China

The aggregation behavior and structure of hydrophobically modified block copolymers of acrylamide and 2-phenoxylethylacrylate were investigated by viscometry, 1H NMR relaxation, 2D NOESY, fluorescence and dynamic light scattering. It Was found that the aggregation behavior was strongly dependent on the concentration of polymer solution and the hydrophobe contents. With varying concentration from 2.0, 6.0, 8.0 to 12.0 g/L, there were different aggregate morphologies distributed in aqueous solutions, such as monopolymer chain, micelle-like aggregate, multi-micelle aggregate and cross-linked network. According to the model of aggregation, it can give a reasonable explanation on the large magnitude enhancement of viscosity with the increasing of polymer concentration. Additional data of 2D NOESY and fluorescence show that the copolymer with higher hydrophobe content（molar fraction≥ 1%） is likely to form intra-molecular association.

关键词： Aggregation behavior and structure Hydrophobically modified Copolymer P(AM/POEA)

Study of thermal decoherence of harmonic oscillators

在线全文

学校读者我要写书评

暂无评论

原子与分子物理学报 2025年第5期42卷 108-114页

作者： LI jian ZHOU Gao-Liang YAN Zheng-Xin LIU Wei wang Zhao-Qi College of Science Xi’an University of Science and TechnologyXi’an 710054China

The thermal decoherence of harmonic oscillators is investigated *** quantum system presented here is a one-dimensional oscillator with angular frequency,which is surrounded by a thermal bath of environmental *** are various environmental oscillators with different angular frequency(below an ultraviolet cutoff).At the beginning,the quantum system is a pure state and the environmental oscillators are in thermodynamic equilibrium with *** a period,the system-environment interactions inspire significant decoherence of the quantum *** decoherence is displayed by explicit calculations of the purity and von Neumann entropy of the quantum *** is worth noting that the decoherence could be significant even in the weak coupling and low temperature case due to the large amount of environmental degrees of *** the decoherence process is inspired between the quantum system and an ordinary thermal environment here,the thermal decoherence result is quite general.

关键词： Quantum decoherence Grand canonical ensemble Oscillators