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相对V模与相对V环
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作者 张顺华 杨德平 《山东大学学报(自然科学版)》 CSCD 1998年第3期248-253,共6页
把V模、V环推广到遗传扭论中,定义并刻划了τV模、τV环以及FV模、FV环.讨论了它们与V模、V环的关系以及T平模的内射包,证明了可换的T正则环是τV环.
关键词 遗传扭论 τv模 τv Fv模 Fv
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相对V─模
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作者 王顶国 《黄淮学刊(自然科学版)》 CAS 1994年第1期48-51,共4页
本文相对扭理论τ,探讨使─切τ─扭单模皆τ─M─内射的R─模M,给出此类模的刻划.
关键词 扭理论 v模 M内射 相对v模
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V型模中薄板弯曲的弹性变形和弹塑性变形分析 被引量:1
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作者 李湘生 纪胜如 《锻压技术》 CAS CSCD 北大核心 1998年第6期21-24,共4页
对薄板在V型模中弯曲的弹性变形和弹塑性变形进行了深入的理论分析,指出弯曲变形常伴有弯曲支点的移动,给出了弯曲支点位置与弯曲力的关系及极限弹性弯曲曲率半径,为深入研究弯曲回弹提供了基础。
关键词 v型弯曲 变形分析 薄板 回弹 v
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关于整环上的v—模理论
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作者 王芳贵 《南京大学学报(数学半年刊)》 CAS 北大核心 1995年第1期111-115,共5页
本文对整环R及其商域K,提出了K^n中分式v-模的概念,它是整环中v-分式理想的自然推广。同时刻划了v-素理想,v-分式模的素子模之间的关系。
关键词 整环 商域 分式 素子 v模
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3Cr2W8V铜管挤压模垫开裂分析 被引量:1
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作者 汪庆华 陈宝丽 杨振华 《五金科技》 2004年第1期21-24,共4页
通过锻造,退火,以及淬回火组织等方面分析了3Cr2W8V铜管挤压模垫早期开裂的原因。在3Cr2W8V钢中观察到退火孪晶组织。退火孪晶是在锻造停锻后,利用锻造余热退火时形成的组织,在此退火过程中形成大量混晶。提出开裂的主要原因是由锻... 通过锻造,退火,以及淬回火组织等方面分析了3Cr2W8V铜管挤压模垫早期开裂的原因。在3Cr2W8V钢中观察到退火孪晶组织。退火孪晶是在锻造停锻后,利用锻造余热退火时形成的组织,在此退火过程中形成大量混晶。提出开裂的主要原因是由锻造停锻后的冷却不合理,产生二次碳化物,混晶组织发生遗传,以及热处理淬火加热不足等缺陷引起。断口特征是低周疲劳宏观断口形貌。 展开更多
关键词 3Cr2W8v铜管挤压 开裂原因 退火孪晶组织 锻造 混晶 热处理 淬火
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V形件自由弯曲应力分析和最大弯矩计算公式 被引量:4
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作者 柳建安 舒丽萍 《中南林业科技大学学报》 CAS CSCD 北大核心 2007年第3期141-144,共4页
根据金属塑性成形原理和平板理论,结合卸载前后的板料的弯曲特点,推导出了V形件自由弯曲时的应力和最大弯矩的计算公式,为研究V形件自由弯曲时的回弹、破裂和冲压设备的选型提供理论依据.
关键词 v形件弯曲 塑性成形 应力 弯矩
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Semi-active control for vibration attenuation of vehicle suspension with symmetric MR damper
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作者 王恩荣 马晓青 《Journal of Southeast University(English Edition)》 EI CAS 2003年第3期264-269,共6页
A semi-active force tracking PI controller is formulated and analyzed for a magnetorheological (MR) fluid-based damper in conjunction with a quarter-vehicle model. Two different models of the MR-damper are integrated ... A semi-active force tracking PI controller is formulated and analyzed for a magnetorheological (MR) fluid-based damper in conjunction with a quarter-vehicle model. Two different models of the MR-damper are integrated into the closed-loop system model, which includes: a model based upon the mean force-velocity (f-v) behaviour; and a model synthesis comprising inherent nonsmooth hysteretic force and the force limiting properties of the MR damper. The vehicle models are analyzed to study the vibration attenuation performance of the MR-damper using the semi-active force tracking PI control algorithm. The simulation results are also presented to demonstrate the influence of the damper nonlinearity, specifically the hysteresis, on the suspension performance. The results show that the proposed control strategy can yield superior vibration attenuation performance of the vehicle suspension actuated by the controllable MR-damper not only in the sprung mass resonance and the ride zones, but also in the vicinity of the wheel-hop. The results further show that the presence of damper hystersis deteriorates the suspension performance. 展开更多
关键词 magneto-rheological damper vehicle suspension hysteresis model semi-active control
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工业应用高压、低纹波电流模Buck型DC-DC芯片设计 被引量:2
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作者 孙彪 王甲 《集成电路应用》 2016年第1期28-31,共4页
本文探讨一款工业应用芯片,低输出纹波同步Buck、纹波小于0.1%、最高效率达93%、可在输入电压4.7V^40V范围内工作。芯片具有PFM、PSM控制模式,提高轻载效率,同时芯片内部集成了过流、过压及过温保护电路。芯片已在HHNEC 0.35μm BDC工... 本文探讨一款工业应用芯片,低输出纹波同步Buck、纹波小于0.1%、最高效率达93%、可在输入电压4.7V^40V范围内工作。芯片具有PFM、PSM控制模式,提高轻载效率,同时芯片内部集成了过流、过压及过温保护电路。芯片已在HHNEC 0.35μm BDC工艺流片,并测试验证。 展开更多
关键词 集成电路设计 DC-DC 40v电流 同步BUCK
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A Matlab/Simulink-Based Photovoltaic Array Model Employing SimPowerSystems Toolbox 被引量:1
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作者 Samer Said Ahmed Massoud +1 位作者 Mohieddine Benammar Shehab Ahmed 《Journal of Energy and Power Engineering》 2012年第12期1965-1975,共11页
The modeling of PV (photovoltaic) systems is very crucial for embedded power system applications and maximum power point tracking. This paper presents a PV array model using Matlab/Simulink with the assistance of Si... The modeling of PV (photovoltaic) systems is very crucial for embedded power system applications and maximum power point tracking. This paper presents a PV array model using Matlab/Simulink with the assistance of SimPowerSystem toolbox. The PV cell is considered as the main building block for simulating and monitoring the PV array performance. The PV model has been developed and used as Simulink subsystems where the effect of solar insolation and PV array temperature on commercial PV modules have been studied throughout the simulated I-V and P-V output characteristics. The proposed model facilitates simulating the dynamic performance of PV-based power systems. The effect of different partial shading patterns of PV arrays under different configurations has been studied. 展开更多
关键词 MODELING Pv solar energy Matlab shading.
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基于容阻建模技术的SOFC电堆数值模拟
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作者 黄刘松 张会生 《能源技术》 2007年第4期221-227,共7页
借助MATLAB软件,通过建模对固体氧化物燃料电池堆的运行进行仿真。为了计算的方便,模型采用了容阻建模技术。采用由质量守恒、能量守恒、动量守恒和电化学过程组成的模型,对SOFC电堆通道中的气体组成、温度分布、电压分布和电流密度分... 借助MATLAB软件,通过建模对固体氧化物燃料电池堆的运行进行仿真。为了计算的方便,模型采用了容阻建模技术。采用由质量守恒、能量守恒、动量守恒和电化学过程组成的模型,对SOFC电堆通道中的气体组成、温度分布、电压分布和电流密度分布进行了计算分析。这些分析结果可对电堆的设计提供参考。 展开更多
关键词 固体氧化物燃料电池(SOFC) 数值 v—R建技术
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An Instrument Variable Model of the Impact of Financing Decisions on Performance of Small Businesses in Australia's Pre-global Financial Crisis
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作者 LI Yongqiang Anona Armstrong Andrew Clarke 《Journal of Modern Accounting and Auditing》 2012年第7期1052-1065,共14页
Firm level empirical research on the impact of financing decisions on small business performance is scarce in the Australian context. This study adopts an instrument variable (IV) approach to analyze the impact of f... Firm level empirical research on the impact of financing decisions on small business performance is scarce in the Australian context. This study adopts an instrument variable (IV) approach to analyze the impact of financing decisions, in particular, equity or debt are obtained, on the performance of small businesses by using the panel data from Australian Bureau of Statistics (ABS) Business Longitudinal Database (BLD) 2004-2005, 2005-2006, and 2006-2007. Performance variables, i.e., sales and expenditure, are used as dependent variables. Equity and debt obtained are used as independent variables (or known as treatments). IV includes size of the business, age of the business, number of locations, and industry division etc.. The results from IV modeling outperformed those obtained from OLS (Ordinary Least Squares). Findings include: (1) financing has significantly positive impacts on the performance of small businesses in Australia; (2) equity and debt financing are used as alternatives, comparatively, equity financing is preferred; (3) capital purchases are largely funded by debt financing, while non-capital purchases and salary expenses are funded by equity financing; and (4) equity financing is more often used by firms with increasing capital purchases and declining non-capital purchases, while debt financing is used by firms with the opposite trends. The paper concludes with a discussion of the limitations of this research and future research's directions. 展开更多
关键词 equity financing debt financing small business PERFORMANCE empirical study
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A Prelude Staircase to a Type V Intermittency in Two—Dimensional Discontinuous Maps 被引量:2
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作者 WANGXU-Ming ZHAOJin-Gang HEDa-Ren 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第6期657-662,共6页
A sequence of periodic attractors has been observed in a two-dimensional discontinuous map, which canbe considered as a model of impact oscillator. The so-called 'transfer number', which is defined as the mean... A sequence of periodic attractors has been observed in a two-dimensional discontinuous map, which canbe considered as a model of impact oscillator. The so-called 'transfer number', which is defined as the mean numberof transfer from non-impact state to impact state per iteration, is locked onto a lot of rational values to form a curveconsisting of many steps. Our numerical investigation confirms that every step is confined by conditions created by thecollision between the periodic orbit and the discontinuous boundary of the system. After the last collision the systemshows a chaotic motion with intermittent characteristics. Therefore the staircase can be addressed as a 'prelude staircaseto type V intermittency'. The similar phenomenon has also been observed in a model of electric circuit. These resultsof our study suggest that this kind of staircases is common in two (or even higher) dimensional discontinuous maps. 展开更多
关键词 two-dimensional map type v intermittency prelude staircase
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两种铜母线热挤压模的使用情况探讨
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作者 朱长榕 《有色金属加工》 CAS 2004年第5期24-26,7,共4页
本文介绍了3Cr2W8V合金钢模和金属陶瓷模的主要特点,分析了这两种挤压模在铜母线热挤压生产中的使用性能。实践表明,在铜母线热挤压生产中,金属陶瓷模在许多方面优于3Cr2W8V合金钢模。
关键词 3Cr2W8v合金钢 金属陶瓷 铜母线 挤压
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基于卷积神经网络的半身裙款式特征分类识别 被引量:6
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作者 邓莹洁 罗戎蕾 《现代纺织技术》 北大核心 2021年第6期98-105,共8页
针对服装特征分类识别不够全面、较多分类特征导致效果较差的问题,提出一种带有Inception v2模组的快速区域卷积神经网络模型的女装半身裙多特征分类识别方法。建立一个包含8类款式、11种颜色、5种图案、4种长度,共计28种类别标签的女... 针对服装特征分类识别不够全面、较多分类特征导致效果较差的问题,提出一种带有Inception v2模组的快速区域卷积神经网络模型的女装半身裙多特征分类识别方法。建立一个包含8类款式、11种颜色、5种图案、4种长度,共计28种类别标签的女装半身裙样本库;以快速区域卷积神经网络(Faster r-cnn)结构为基础,引入一个Inception v2模组,对半身裙的款式及多种特征进行学习训练,通过全连接层将来自Faster r-cnn主干网络和Inception v2的分类信息进行特征融合并共享损失,以提高算法的准确率;将目标检测框与分类结果一起输出,在对半身裙图像精准定位的基础上实现了半身裙款式及常见特征的分类识别。结果表明:该方法的平均分类准确率为92.8%,可以有效地对女装半身裙款式、特征进行分类识别,并且可用于实际场景的服装图片中。 展开更多
关键词 卷积神经网络 Inception v2 快速区域卷积神经网络 女装半身裙
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悬臂连续梁0号块支架设计及检算 被引量:4
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作者 韩海龙 《山西建筑》 2011年第31期158-159,共2页
介绍了石武高速铁路某特大桥跨邢临高速公路预应力混凝土连续箱梁0号块支架材料的选择、施工方案的设计,并通过MIDAS/Civil V2006建模对支架的受力进行了检算,表明各杆件受力均满足要求。
关键词 高速铁路特大桥 连续箱梁 0号块支架 MIDAS/CIvIL v2006建
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Geometric Design of Anode-Supported Micro-Tubular Solid Oxide Fuel Cells by Multiphysics Simulations
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作者 施红玉 朱江 林子敬 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2017年第4期411-417,I0001,共8页
High volumetric power density (VPD) is the basis for the commercial success of micro-tubular solid oxide fuel cells (mtSOFCs). To find maximal VPD (MVPD) for anode-supported mtSOFC (as-mtSOFC), the effects of ... High volumetric power density (VPD) is the basis for the commercial success of micro-tubular solid oxide fuel cells (mtSOFCs). To find maximal VPD (MVPD) for anode-supported mtSOFC (as-mtSOFC), the effects of geometric parameters on VPD are analyzed and the anode thickness, tan, and the cathode length, lea, are identified as the key design parameters. Thermo-fluid electrochemical models were built to examine the dependence of the electrical output on the cell parameters. The multiphysics model is validated by reproducing the experimental I-V curves with no adjustable parameters. The optimal lea and the corresponding MVPDs are then determined by the multiphysics model for 20 combinations of rin, the inner tube radius, and tan. And all these optimization are made at 1073.15 K. The results show that: (i) significant performance improvement may be achieved by geometry optimization, (ii) the seemingly high MVPD of 11 and 14 W/cm^3 can be easily realized for as-mtSOFC with single- and double-terminal anode current collection, respectively. Moreover, the variation of the area specific power density with/cac(2 mm, 40 mm) is determined for three representative (tin, tan) combinations. Besides, it is demonstrated that the current output of mtSOFC with proper geometric parameters is comparable to that of planar SOFC. 展开更多
关键词 I-v relations Thermal fluid electrochemistry model Parametric optimization volumetric power density Anode thickness
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Analysis of an HIV model with distributed delay and behavior change
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作者 Hasim A. Obaid Rachid Ouifki Kailash C. Patidar 《International Journal of Biomathematics》 2015年第2期53-75,共23页
We develop and analyze a mathematical model for the transmission dynamics of HIV that accounts for behavioral change. The contact rate is modeled by a decreasing function (response function) of HIV prevalence to ref... We develop and analyze a mathematical model for the transmission dynamics of HIV that accounts for behavioral change. The contact rate is modeled by a decreasing function (response function) of HIV prevalence to reflect a reduction in risky behavior that results from the awareness of individuals to a higher HIV prevalence. The model also includes a distributed delay representing the time needed for individuals to reduce their risky behavior. We study mathematically and numerically the impact of the response function and the distributed delay on the model's dynamics. Threshold values for the delay at which the system destabilizes and periodic solutions can arise through Hopf bifurcation are determined. 展开更多
关键词 HIv distributed delay basic reproduction number EQUILIBRIUM STABILITY Hopf bifurcation.
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广州新光大桥六号墩斜腿施工及控制
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作者 陈永刚 《公路交通科技(应用技术版)》 CAS CSCD 2009年第6期147-149,共3页
新光大桥属于广州市新光快速路工程第三合同段。北起于海珠区南洲路上,起点桩号为K4+642.90(1#墩),跨越珠江主航道后,南止于番禺区沙溪村西宁路附近,终点桩号K5+726.10(10#墩)。文章分析了6#墩斜腿施工与施工过程的控制。
关键词 桥梁工程 斜腿、v肢、劲性骨架、底托架、预应力拉杆
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