检索结果-南通市图书馆

Determination of inter-satellite relative position using X-ray pulsars

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science C(Computers and Electronics) 2013年第2期14卷 133-142页

作者： Da-jun FENG Lu-ping XU Hua ZHANG shi-bin SONG School of Electronic Engineering Xidian University Institute of Astronautics and Aeronautics Xidian University

Pulsars are rapidly rotating neutron stars that generate pulsed electromagnetic radiation.A new method for intersatellite relative position determination between a global navigation satellite system(GNSS) and spacecraft using X-ray pulsars is proposed in this *** geometric model of this method is formulated,and two different resolution algorithms are introduced and *** phase cycle ambiguity resolution is investigated,and a new strategy is proposed and *** the direct vector parameters of the pulsar,geometric dilution of precision(GDOP) is *** is shown that this method has advantages of simplicity and efficiency,and is able to eliminate the clock *** analytical results are verified numerically via computer simulations.

关键词： Pulsar navigation Position determination Phase cycle ambiguity Geometric dilution of precision(GDOP)

Crystallization process and soft magnetic properties of nanocrystalline (Fe0.5 Co0.5 ) 86 Hf7 B6 Cu1 alloy used in elevated temperature applications

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2004年第z1期14卷 478-481页

作者： LIANG Xiu-bing J.Ferenc T.Kulik XU bin-shi Faculty of Materials Science and Engineering Warsaw University of Technologyul. Woeoska 141 Warsaw 02-507 Poland National Key Laboratory for Remanufacturing Academy of Armored Forces Engineering Beijing 100072 China Faculty of Materials Science and Engineering Warsaw University of Technologyul. Woeoska 141 Warsaw 02-507 Poland Faculty of Materials Science and Engineering Warsaw University of Technologyul. Woeoska 141 Warsaw 02-507 Poland National Key Laboratory for Remanufacturing Academy of Armored Forces Engineering Beijing 100072 China

Nanocrystalline (Fe0.5 Co0.5 )86 Hf7 B6 Cu1 HITPERM alloy was investigated as the candidate of soft magnetic material for high temperature applications, compared with Fe86 Hf7B6 Cu1 NANOPERM alloy. Amorphous alloy ribbons were prepared by single-roller melt-spinning technology. Crystallization process of as-quenched ribbon was investigated using differential scanning calorimeter at different heating rates. The coercivity was determined from quasi-static hysteresis loop measured at room temperature using a computerized hysteresis loop tracer. X-ray diffraction with Cu Kα radiation was used to determine the structure. The vibrating sample magnetometer was usedto measure the magnetization as a function of temperature of the nanocrystllized alloys. That Co substitution for Fein alloy enhances the Curie temperature of amorphous alloy and the magnetization of nanocrystalline alloy at hightemperature. After annealing amorphous precursor, the optimum nanocrystalline alloy obtained shows the local minimum coercivity. The coercivity increases with the increasing annealing temperature corresponding to the formation of ferromagnetic phase in the secondary crystallization.

关键词： nanocrystalline soft magnetic material crystallization process activation energy coercivity magnetization

Wear-resistance and anti-scuffing of multi-arc ion plating molybdenum films

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2004年第z1期14卷 391-394页

作者： WANG Hai-dou XU bin-shi LIU Jia-jun ZHUANG Da-ming National Key Laboratory for Remanufacturing Academy of Armored Force Engineering Beijing 100072 China National Key Laboratory for Remanufacturing Academy of Armored Force Engineering Beijing 100072 China Department of Mechanical Engineering Tsinghua University Beijing 100084 China Department of Mechanical Engineering Tsinghua University Beijing 100084 China

The multi-arc ion plating technology was employed to prepare the molybdenum films with thickness of 3 μm on the AISI 1045 steel. The wear and scuffing tests were carried out on the ball-on-disc tester. AFM and SEM equipped with EDS were adopted to observe and analyze the morphologies and element compositions of surface,cross-section and worn scar of the Mo film. The phase structure was studied by XRD and the bonding strength between Mo film and substrate was measured by scratching tester. The tribological experiments show that the Mo film possesses a good wear-resistance and an excellent anti-scuffing property. The failure mechanism of Mo film under extreme condition is flaking off.

关键词： multi-arc ion plating molybdenum film wear and scuffing

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

柏苦苓合剂治疗急性湿疹的临床观察

中国中医急症 2024年第10期33卷 1792-1795页

作者：时文远刘星黄梅花涂焱华汪选斌施斌湖北医药学院附属人民医院湖北十堰442000 湖北省武汉市肺科医院湖北武汉430030

目的观察柏苦苓合剂治疗急性湿疹(湿热浸淫证)的临床疗效和安全性。方法采用随机数字表法将患者127例分为西药组40例、中药组44例、联合组43例。西药组采用左西替利嗪片及硼酸外敷等治疗;中药组采用柏苦苓合剂治疗;联合组以上述两组... 详细信息

目的观察柏苦苓合剂治疗急性湿疹(湿热浸淫证)的临床疗效和安全性。方法采用随机数字表法将患者127例分为西药组40例、中药组44例、联合组43例。西药组采用左西替利嗪片及硼酸外敷等治疗;中药组采用柏苦苓合剂治疗;联合组以上述两组的中、西药联合治疗。观察各组治疗前、治疗2周、随访时瘙痒程度、皮损面积、湿疹严重指数(EASI)评分、中医证候的评分变化和治疗期间的不良反应。结果治疗2周时西药组、中药组、联合组患者瘙痒程度评分、皮损面积评分、中医证候评分均较治疗前明显下降(P <0.05)。随访时联合组的各项评分优于中药组和西药组(P <0.05)。此外西药组的复发率为40.63%,高于其他两组(P <0.05)。结论柏苦苓合剂治疗急性湿疹(湿热浸淫证)可明显减轻临床症状,较单纯西药治疗复发率低,且无不良反应。

关键词：急性湿疹柏苦苓合剂中医疗法临床疗效

Effect of SiO2 substitution with Al2O3 during high-Al TRIP steel casting on crystallization and structure of low-basicity CaO–SiO2-based mold flux

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2020年第1期27卷 33-41页

作者： Ding-li Zheng Cheng-bin shi Zhi-jun Li Jing Li Jung-wook Cho State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Division of Steelmaking Shougang Qian’an Iron and Steel Co.Ltd.Qian’an 064404HebeiChina Graduate Institute of Ferrous Technology Pohang University of Science and TechnologyPohang 790-784Republic of Korea

The crystallization and structure of non-conventional lime-silica-based mold fluxes after undergoing slag-steel interaction in casting high-AI transformation induced plasticity(TRIP)steel were *** results showed that the crystallization temperatures of the mold fluxes decreased with decreasing the SiO2/Al2O3 ratio,and CaO/MnO2 ratio had an opposite effect on the crystallization *** crystalline phases precipitated in the mold flux were Ca4Si2O7F2 and *** SiO2/Al2O3 ratio and increasing CaO/MnO2 ratio in the mold fluxes have no influence on the types of crystalline *** dominant crystalline phase precipitated in each mold flux was Ca4Si2O7F2 with dendritic morphology,except for part of that with globular morphology in the mold flux without MnO2 ***4 crystals are distributed in the space among Ca4Si2O7F2 *** size of Ca4Si2O7F2 crystals in the slag with higher S1O2/AI2O3 ratio is smaller,which is attributed to the polymerization degree of the mold flux with increasing SiO2/Al2O3 ratio.[SiO4]-tetrahedral,[AlO4]-tetrahedral and T-O-T bending(T denotes Si or Al)depolymerized gradually with decreasing SiO2/Al2O3 ratio,and an opposite trend was observed for the case with increasing CaO/MnO2 *** polymerization degree of the mold fluxes decreased,which would result in the decrease in the viscosity of the mold fluxes.

关键词： Mold flux Crystallization Structure Continuous casting High-AI steel

Effect of Mn content on microstructure, tensile and impact properties of SA508Gr.4N steel for reactor pressure vessel

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 Iron and Steel Research International 2020年第4期27卷 461-470页

作者： Xi-kou He Zhi-qiang Yang Zhen Wang shi-bin Qiao Zheng-dong Liu Institute for Special Steels Central Iron and Steel Research InstituteBeijing 100081China Technology Center of Ma’anshan Iron and Steel Co. Ltd.Ma’anshan 243000AnhuiChina

The effect of manganese(Mn)on the microstructure,tensile and impact properties of SA508Gr.4N steel has been experimentally *** influence of Mn content on the substructure of SA508Gr.4N steel was investigated using the scanning electron microscope,electron back-scattered diffractometer and transmission electron *** was found that the increased Mn content had a beneficial effect on both strength and *** of microstructure revealed smaller size of block and larger number of high-angle grain boundaries with higher Mn *** change of the ultimate tensile strength and toughness with increasing Mn content was attributed to the increased hardenability,the number of high-angle grain boundaries and the crack propagation path by the block refining.

关键词： Mn element SA508Gr.4N steel Microstructure Charpy impact toughness Substructure

Experimental study on the deformation and failure mechanism of overburden rock during coal mining using a comprehensive intelligent sensing method

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 Rock Mechanics and Geotechnical Engineering 2022年第5期14卷 1626-1641页

作者： Gang Cheng Wentao Xu bin shi Jinghong Wu binyang Sun Honghu Zhu School of Computer Science North China Institute of Science and TechnologyBeijing101601China School of Earth Sciences and Engineering Nanjing UniversityNanjing210023China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China School of Civil Engineering Suzhou University of Science and TechnologySuzhou215009China State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and TechnologyHuainan232001China

Understanding the spatiotemporal evolution of overburden deformation during coal mining is still a challenge in engineering practice due to the limitation of monitoring techniques. Taking the Yangliu Coal Mine as an example, a similarity model test was designed and conducted to investigate the deformation and failure mechanism of overlying rocks in this study. Distributed fiber optic sensing(DFOS), highdensity electrical resistivity tomography(HD-ERT) and close-range photogrammetry(CRP) technologies were used in the test for comprehensive analyses. The combined use of the three methods facilitates the investigation of the spatiotemporal evolution characteristics of overburden deformation, showing that the mining-induced deformation of overburden strata was a dynamic evolution process. This process was accompanied by the formation, propagation, closure and redevelopment of separation ***, the key rock stratum with high strength and high-quality lithology played a crucial role in the whole process of overburden deformation. There were generally three failure modes of overburden rock layers, including bending and tension, overall shearing, and shearing and sliding. Shear failure often leads to overburden falling off in blocks, which poses a serious threat to mining safety. Therefore, realtime and accurate monitoring of overburden deformation is of great significance for the safe mining of underground coal seams.

关键词： Similarity model Distributed fiber optic sensing(DFOS) Overburden deformation Failure mechanism Coal seam mining

Fiber optic sensing and performance evaluation of a water conveyance tunnel with composite linings under super-high internal pressures

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2023年第8期15卷 1997-2012页

作者： Deyang Wang Honghu Zhu Jingwu Huang Zhenrui Yan Xing Zheng bin shi School of Earth Sciences and Engineering Nanjing UniversityNanjing210023China Nanjing University High-Tech Institute at Suzhou Suzhou215123China Guangdong Hydropower Planning and Design Institute Guangzhou510635China Zhejiang Huadong Construction Engineering Co.Ltd. Hangzhou310012China

For long-distance water conveyance shield tunnels in operation,the high internal water pressure may cause excessive deformation of composite linings,affecting their structural integrity and ***,the deformation and failure characteristics of lining structures under internal water pressure are not well investigated in the literature,particularly for three-layer composite *** study presents an in situ experimental investigation on the response of two types of composite linings(*** and combined lining structures)subjected to internal pressures,in which a fiber optic nerve system(FONS)equipped with distributed strain and displacement sensing nerves was employed to monitor the performance of the two composite linings during *** experimental results clearly show that the damage of the tunnel lining under different internal pressures was mainly located in the self-compaction concrete *** separated lining structure responded more aggressively to the variations in internal pressures than the combined ***,two evaluation indices,*** displacement and effective stiffness coefficient,are proposed for describing the changes in the structural bearing *** effective stiffness coefficients of the two types of lining structures were reduced by 39.4%and 29.5%,*** the convenience of field monitoring,it is suggested that the average strains at different layers can be used as characteristic parameters for estimating the health conditions of lining structures in *** analysis results provide a practical reference for the design and health evaluation of water conveyance shield tunnels with composite linings.

关键词： Water conveyance tunnel Composite lining interface Strain measurement Geotechnical monitoring Fiber optic nerve system(FONS)

以附加阻尼比为目标的黏弹性阻尼器设计方法研究

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

价值工程 2024年第19期43卷 70-72页

作者：叶鹏秦桧荣郑洁余石斌昆明理工大学昆明650500 云南省建筑科学研究院有限公司昆明650021

以黏弹性阻尼器附加的阻尼比为控制目标,依据抗规中计算阻尼比的方法,建立单质点系的附加阻尼比控制函数。将多质点系等效成单质点系,依据剪力系数得到减震结构的层剪力,由此部分楼层需要增加楼层侧移刚度,增加的刚度即黏弹性阻尼器需... 详细信息

以黏弹性阻尼器附加的阻尼比为控制目标,依据抗规中计算阻尼比的方法,建立单质点系的附加阻尼比控制函数。将多质点系等效成单质点系,依据剪力系数得到减震结构的层剪力,由此部分楼层需要增加楼层侧移刚度,增加的刚度即黏弹性阻尼器需求储存刚度,从而得到黏弹性阻尼器阻尼系数。工程案例结果表明:以附加阻尼比为控制目标来进行黏弹性阻尼减震结构设计的方法可行。

关键词：黏弹性阻尼器附加阻尼比损失系数刚度分配

维普期刊数据库博看期刊