检索结果-南通市图书馆

Inverse Analysis of Origin-Destination Matrix for Microscopic Traffic Simulator

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2017年第1期113卷 71-87页

作者： K.Abe h.fujii S.Yoshimura The University of Tokyo BunkyoTokyoJapan

Microscopic traffic simulations are useful for solving various trafficrelated problems,*** jams and accidents,local and global environmental and energy problems,maintaining mobility in aging societies,and evacuation planning for natural as well as man-made *** origin-destination(OD)matrix is often used as the input to represent traffic demands into traffic *** this study,we propose an indirect method for estimating the OD matrix using a traffic simulator as an internal *** proposed method is designed to output results that are consistent with the input of the *** method consists of the following steps:(1)calculating link traffic volume from the OD matrix,and(2)updating the *** estimated matrix is updated iteratively until it converges to a predefined tolerance *** experiments are then conducted using the proposed method on a grid network and on a representation of an actual road ***,we discuss the characteristics of the proposed method and the non-negative constraint for the traffic volume.

关键词： OD estimation inverse problem traffic simulation Levenberg-Marquardt method iterative method

Friction stir spot welding of SPCC low carbon steel plates at extremely low welding temperature

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

Journal of Materials Science & Technology 2019年第5期35卷 733-741页

作者： Y.F.Sun h.fujii Y.Sato Y.Morisada Joining and Welding Research Institute Osaka University 11-1 Mihogaoka Ibaraki 567-004Japan School of Materials Science and Engineering Zhengzhou University Zhengzhou 450001 China

Friction stir spot welding (FSSW) was applied to 2.0 mm thick steel plate cold-rolled commercial (SPCC) low carbon steel plates at a very low rotation speed that ranged from 5 to 50rpm, which was much lower than that generally used for the conventional FSSW technique. Due to the very low heat input, the welding processes could therefore be completed at a peak welding temperature below 160℃. As a result, a significantly refined microstructure with an average grain size of about 0.41μm was formed in the stir zone of the joints and the JI {0-11 } and J2{1-1O} shear textures were the dominant components, which are different from the D1{11-2} and D2{-1-12} shear textures formed in the conventional FSSW joints. In addition, no heat affected zone could be detected along the crosssectional plane of the joints. Although a few void-like non-bonded areas were still observed along the interface between the upper and lower steel plates, the shear tensile loads of the joints increased to about 10.0 kN when welded at a condition of 8t, 20rpm and 30 s, and the joints fractured through the plug failure mode.

关键词： Friction stir spot welding Dynamic recrystallization Microstructure Steel

Rupture locations of friction stir welded joints of AA2017-T351 and AA6061-T6 aluminum alloys

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 2005年第3期15卷 515-518页

作者：刘会杰冯吉才 h.fujii M.Maeda K.Nogi State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China Joining and Welding Research Institute Osaka University Osaka 567-0047 Japan

The tensile rupture locations of friction stir welded joints of AA2017-T351 and AA6061-T6 aluminum alloys were examined. The experiments show that the rupture locations of the joints are different for the two aluminum alloys, which are influenced by the welding parameters. When the joints are free of welding defects, the AA2017-T351 joints are ruptured in the weld nugget adjacent to the thermo-mechanically affected zone on the advancing side and the rupture surfaces appear as oval contours of the weld nugget, while the AA6061-T6 joints are ruptured in the heat affected zone on the retreating side and the rupture surfaces are inclined at a certain degree to the bottom surfaces of the joints. When welding defects are present in the joints, the AA2017-T351 joints are ruptured in the weld center, while the AA6061-T6 joints are ruptured on the retreating side near the weld center. The rupture locations of the joints are dependent on the internal structures of the joints and can be explained through them.

关键词：铝合金摩擦搅拌焊接韧性测试技术参数局部破裂

Evaluation of dynamic development of grain structure during friction stir welding of pure copper using a quasi in situ method

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2019年第7期35卷 1412-1421页

作者： X.C.Liu Y.F.Sun T.Nagira K.Ushioda h.fujii Joining and Welding Research Institute Osaka University11-1 MihogaokaIbarakiOsaka567-0047Japan School of Materials Science and Engineering Northwestern Polytechnical UniversityXi'an710072China School of Materials Science and Engineering Zhengzhou UniversityZhengzhou450001China

By employing a quasi in situ method, we investigated the dynamic evolution of the grain structure con-sidering the material flow, strain, and strain rate in the friction stir welding of pure copper. The tool' stop action' and rapid cooling were employed and a brass foil was used as a marker to show the material flow path. The grain structure along the material flow path was characterised using electron backscatter diffraction. Static recrystallization occurs for the work-hardened base material in the preheating stage in front of the tool In the acceleration flow stage, grains are significantly refined by plastic deforma-tion, discontinuous dynamic recrystallization, annealing twinning during the strain-induced boundary migration and slight continuous dynamic recrystallization. In the deceleration flow stage, due to a strain reversal, the grain first coarsens, and is thereafter refined again. Finally, the hot-deformed material in the shoulder-affected zone is ‘frozen’ directly whereas that in the probe-affected zone undergoes signif-icant annealing;thus, the recrystallized microstructure and 45°-rotated cube texture are obtained in the probe-affected zone.

关键词： Friction stir welding Grain structure Material flow Pure copper EBSD

在线全文

学校读者我要写书评

暂无评论

应用液闪效率示踪技术测定圆片样品的活度

核农学通报 1987年第4期 34-36页

作者： h.fujii 周洪杰

液闪计数已成为3h 和14C 等数十种弱β核素的常规放射性分析技术。其优点是可以在4π几何条件下进行无自吸收的放射性测量,因而成功地应用于大部分纯β及β-Υ辐射体测量。液闪技术可获得很高的计数效率。但如果没有标准样品,确定某种... 详细信息

液闪计数已成为3h 和14C 等数十种弱β核素的常规放射性分析技术。其优点是可以在4π几何条件下进行无自吸收的放射性测量,因而成功地应用于大部分纯β及β-Υ辐射体测量。液闪技术可获得很高的计数效率。但如果没有标准样品,确定某种核素的活度是不太容易的。为了克服这种缺陷,我们（1984）提出了一种液闪效率示踪技术,可以采用与被测样品不同的核素作为标准核素,有效地用于多种β-辐射体活度的测定。本研究用效率示踪技术测定集中在圆片上的各种放射性物质的活度。由于样品容易制备,圆片计数技术已被广泛使用。不过它有一个缺点,即不能应用通常的外标准道比法或样品道比法进行猝灭校正。试验发现,效率示踪技术易测定圆片样品的活度。文中将测定结果与6种放射性核素的标准值进行了比较。

关键词：效率示踪圆片液闪活度热力学函数技术测定

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

粗糙端面光纤光散射特性的理论计算

应用光学 1986年第3期 49-51页

作者： S.Jutamulia h.fujii T.Asakura 周晨波

将光纤输出端用化学方法弄粗糙,使输出激光辐射均匀,用于医学上的肿瘤治疗,在实验上已有一定进展。这里着重在理论上研究光纤粗糙端面的光散射特性,理论和实验结果相符。

关键词：光纤光导纤维平面波导传播常数传输常数理论计算光纤输出端面

GAME-TIBET青藏高原云和降水综合观测概况及初步结果

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

高原气象 1999年第3期18卷 441-450页

作者：刘黎平楚荣忠宋新民周筠君冯锦明陈成品张彤 S.Shimizu K.Ueno T.Koike h.fujii h.Yamada Y.Aoi T.Ueno J.horikomi M.Kajikawa RShirooka J.Teshima 中国科学院兰州高原大气物理研究所甘肃省兰州市730000 EarthObservationResearchCenter NationalSpaceDevelopmentAgencyofJapan TheUniversityofShigaPrefecture ShigaJapan NagaokaUniversityofTechnology DepartmentofEarthandPlanetaryScience HokkaidoUniversity AkiktaUniversity Japan hokkaidoNationalAgriculturalExperimentStation KyushuUniversity

对中日合作青藏高原能量水分循环试验（ＧＡＭＥ ＴＩＢＥＴ）项目中云和降水的多普勒雷达观测使用的气象观测仪器和获取的资料等情况进行了扼要的总结，并给出了那曲地区降水的日变化、不同雨量计测量降水的对比分析、风速... 详细信息

对中日合作青藏高原能量水分循环试验（ＧＡＭＥ ＴＩＢＥＴ）项目中云和降水的多普勒雷达观测使用的气象观测仪器和获取的资料等情况进行了扼要的总结，并给出了那曲地区降水的日变化、不同雨量计测量降水的对比分析、风速对测量降水影响、多普勒雷达资料的个例分析及云的数值模拟等初步结果。

关键词：云降水多普勒雷达综合观测青藏高原

Fluorescence‑Based Calibration Model for In‑Situ Measurement of Micro‑scaled Lubricant Thickness Distribution at Indentation Interface

在线全文

学校读者我要写书评

暂无评论

Nanomanufacturing and Metrology 2024年第2期7卷 76-88页

作者： Motoya Yoshikawa Saeko fujii Shotaro Kadoya Tatsuya Sugihara Masaki Michihata Satoru Takahashi Department of Precision Engineering The University of TokyoHongo 7‑3‑1BunkyoTokyo 113‑8656Japan Department of Mechanical Engineering Osaka UniversityYamadaoka 2‑1SuitaOsaka 565‑0871Japan

This study proposes a model for the measurement of microscale liquid film thickness distribution using fluorescence *** interfacial conditions between the tool and the workpiece in mechanical machining are important for understanding these phenomena and *** this study,indentation tests with transparent tools were used to observe interfaces;however,it was challenging to obtain the signal from a thin fluorescent liquid film on smooth and steeply inclined ***,fluorescence-based measurement,such as laser-induced fluorescence,was *** measure the absolute thickness of the thin fluorescent film,calibration of the measurement system is ***,a theoretical model was proposed considering the multiple reflections of excitation light and fluorescence at the inclined surface between the indenter and *** measuring the profile of the surface topography of the indented workpiece and comparing the results with those measured by a surface profiler,the validity of the proposed calibration method and the performance of this measurement system were *** measured surface profiles,including scratches of 2–4μm,were in good agreement,demonstrating the validity of the proposed method.

关键词： Laser-induced fluorescence(LIF) Thickness distribution In-situ measurement Lubricant Mechanical machining

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

青藏高原那曲地区冰雹天气系统中的大气电场

高原气象 2000年第3期19卷 339-347页

作者：周筠珺陈成品刘黎平楚荣忠冯锦明张彤宋新民 M.Kajikawa h.fujii Y.Aoi T.Koike S.Shimizu K.Ueno 中国科学院寒区旱区环境与工程研究所甘肃省兰州市730000 Akikta University Nagaoka University of Technology Nagaoka Earth Observation Research Center National Space Development Agency of JapanTokyo The University of Shiga Prefecture Shiga

利用 1 998年 4～ 9月间进行的GAME TIBET青藏高原云和降水的多普勒雷达及大气平均电场加强期观测实验资料 ,对青藏高原那曲地区的冰雹天气系统中的大气电场作了定量观测和研究。结果表明 :在降雹过程中大气电场强度基本上均为负值 ,其... 详细信息

利用 1 998年 4～ 9月间进行的GAME TIBET青藏高原云和降水的多普勒雷达及大气平均电场加强期观测实验资料 ,对青藏高原那曲地区的冰雹天气系统中的大气电场作了定量观测和研究。结果表明 :在降雹过程中大气电场强度基本上均为负值 ,其峰值也均强于- 2 2kVm- 1;在降雹过程中随着降雹时间的临近 ,大气电场强度不断增强 ,但降雹开始时大气电场强度并未达到其峰值 ,峰值出现的时刻比开始降雹的时刻略有滞后 ;在各降雹日中 ,较强的大气电场强度基本上对应着各冰雹谱分布段较多的冰雹数目 ,而这种较好的相关在各谱分布段上都表现出来 ;随着降雹时间的临近 ,每 5min闪电频数不断增强。在开始降雹时每 5min闪电频数平均达到 43,峰值的出现时刻略滞后于开始降雹的时刻 ,这一滞后时间一般平均在 3min左右 ;在降雹过程中 ,单位面积中的冰雹数目与对应时段内总闪电数有着较好的对数关系 ,相关系数R为 0 .9540。在降雹过程的时间序列上 ,冰雹云成熟期过后 ,总闪电次数与冰雹降雹率成反相关。

关键词：青藏高原那曲地区冰雹天气大气电场