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CR-CR式多挡自动变速器速度平面构建与分析方法
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作者 宫涛 郝孟军 罗美琴 《机械研究与应用》 2022年第1期124-128,共5页
以CR-CR型6速自动变速器为研究对象,以杠杆法原理为基础,建立各挡等效杠杆及空间速度矢量图,通过基于回转中心的速度平面,对各节点的运动和速度进行分析和计算,验证了结果的正确性。研究结果能广泛应用在教学应用中,丰富自动变速器研究... 以CR-CR型6速自动变速器为研究对象,以杠杆法原理为基础,建立各挡等效杠杆及空间速度矢量图,通过基于回转中心的速度平面,对各节点的运动和速度进行分析和计算,验证了结果的正确性。研究结果能广泛应用在教学应用中,丰富自动变速器研究基础理论。 展开更多
关键词 CR-CR型 杠杆法 速度矢量 速度平面
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实时三平面定量组织速度成像技术与斑点追踪技术评价扩张型心肌病患者左室纵向收缩不同步性 被引量:3
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作者 张婧姝 郑慧 《安徽医科大学学报》 CAS 北大核心 2013年第11期1360-1363,共4页
目的应用实时三平面定量组织速度成像技术(RT-3PE QTVI)与斑点追踪技术(STI)评价扩张型心肌病患者(DCM)左室纵向收缩不同步性。方法 30例正常成人为对照组,30例DCM患者为DCM组。平静状态下获取心尖四腔切面、心尖二腔切面、心尖左室长... 目的应用实时三平面定量组织速度成像技术(RT-3PE QTVI)与斑点追踪技术(STI)评价扩张型心肌病患者(DCM)左室纵向收缩不同步性。方法 30例正常成人为对照组,30例DCM患者为DCM组。平静状态下获取心尖四腔切面、心尖二腔切面、心尖左室长轴切面二维灰阶及RT-3PE QTVI动态图像。双平面Simpson法测量左室射血分数(LVEF);脱机分析测量左室基底段和中间段12节段组织速度峰值(Vs)及达峰时间(Ts),左室基底段、中间段、心尖段18节段纵向应变峰值(Ls)及达峰时间(Tls),并计算其达峰时间的最大差值(Ts-diff、Tls-diff)及其标准差(Ts-SD、TlsSD),作为左室纵向收缩不同步运动的指标。结果①DCM组的左室舒张末内径(LVEDd)、左室收缩末内径(LVESd)、左室舒张末容积(LVEDL)、左室收缩末容积(LVESL)、LVEF及左室短轴缩短率(FS)与对照组相比,差异有统计学意义(P<0.01)。②DCM组各节段Ls及Vs明显低于对照组相应节段,差异有统计学意义(P<0.01)。与对照组比较,DCM组Tls、Ts有明显的提前或延迟,差异有统计学意义(P<0.05)。③与对照组比较,DCM患者的Ts-SD、Tls-SD、Tsdiff、Tls-diff明显增加(P<0.01);Ts-SD、Tls-SD、Ts-diff、Tlsdiff与LVEF呈负相关(r=-0.67、-0.72、-0.75、-0.77,P<0.01)。结论 DCM患者存在左室纵向收缩不同步性。RT-3PE QTVI与STI联合应用对于DCM患者左室纵向收缩不同步评价,优于其中的任何一种技术。 展开更多
关键词 超声心动图描记术 扩张型心肌病 二维斑点追踪技术 实时三平面定量组织速度成像技术
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无极速度图法——一种确定平面机构速度的新方法 被引量:6
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作者 张速 《安徽建筑工业学院学报(自然科学版)》 2003年第4期12-16,共5页
在研究无极速度图的概念、性质和绘制方法的基础上 ,利用无极速度图提出了一种确定平面机构速度的新方法———无极速度图法。该方法确定平面机构速度非常方便 ,并且速度值求得快 ,易于掌握。
关键词 无极速度图法 平面机构速度 图解法 表影线 不动点
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实时三平面组织速度显像技术对冠心病左室心肌节段性室壁运动异常的评价 被引量:2
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作者 王耀 黎春雷 +3 位作者 黄婷 李汉英 杨好意 董常峰 《现代医药卫生》 2013年第4期496-498,共3页
目的探讨实时三平面(tri-plane)组织速度显像(TVI)技术定量检测冠心病患者左室节段性室壁运动异常的应用价值,并比较定量组织速度成像(QTVI)、组织追踪成像(TTI)和组织同步成像(TSI)检出冠脉病变血管支的敏感性。方法在超声Tri-plane技... 目的探讨实时三平面(tri-plane)组织速度显像(TVI)技术定量检测冠心病患者左室节段性室壁运动异常的应用价值,并比较定量组织速度成像(QTVI)、组织追踪成像(TTI)和组织同步成像(TSI)检出冠脉病变血管支的敏感性。方法在超声Tri-plane技术下,对对照组(健康人群)及冠心病组患者,采集标准心尖四腔观、心尖左室两腔观、心尖左室长轴观的左心室6个壁,并分为基底段、中间段和近心尖段共18个节段。各节段分别获得QTVI的速度、时间曲线图,TTI的位移-时间曲线图及TSI彩色编码的峰值速度和时间图。测量各节段的收缩期峰值速度和最大位移,并进行定量分析。结果三种技术定量检测冠心病组左室壁心肌各节段的峰值速度和位移均较对照组明显降低(P<0.05);40例冠心病患者中,TTI对检测冠状动脉病变血管有较高敏感性,达85.0%,与QTVI、TSI比较,差异有统计学意义(P<0.05)。结论 TVI技术能有效定量评价冠心病左室心肌收缩期节段性运动异常;TTI对冠状动脉病变血管检测诊断的敏感性可能优于QTVI和TSI。 展开更多
关键词 超声心动描记术 多普勒 冠状动脉疾病 超声检查 心室功能 室壁运动异常 平面组织速度显影技术
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速度和加速度的研究
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作者 张翠明 李怜杏 《石家庄职业技术学院学报》 2003年第2期1-2,8,共3页
运用新微积分理论 (见文献 [1]) ,定义了瞬时线速率、瞬时线速度、瞬时平面角速率、瞬时平面角速度、瞬时线加速度、瞬时角加速度 .
关键词 速度 速度 微积分理论 瞬时线速率 瞬时线速度 瞬时平面角速率 瞬时平面速度 瞬时线加速度 瞬时角加速度
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Role of Kirkendall effect in diffusion processes in solids 被引量:8
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作者 C.A.C.SEQUEIRA L.AMARAL 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第1期1-11,共11页
In the 1940s, KIRKENDALL showed that diffusion in binary solid solutions cannot be described by only one diffusion coefficient. Rather, one has to consider the diffusivity of both species. His findings changed the tre... In the 1940s, KIRKENDALL showed that diffusion in binary solid solutions cannot be described by only one diffusion coefficient. Rather, one has to consider the diffusivity of both species. His findings changed the treatment of diffusion data and the theory of diffusion itself. A diffusion-based framework was successfully employed to explain the behaviour of the Kirkendall plane. Nonetheless, the complexity of a multiphase diffusion zone and the morphological evolution during interdiffusion requires a physico-chemical approach. The interactions in binary and more complex systems are key issues from both the fundamental and technological points of view. This paper reviews the Kirkendall effect from the circumstances of its discovery to recent developments in its understanding, with broad applicability in materials science and engineering. 展开更多
关键词 Kirkendall effect Kirkendall velocity Kirkendall planes diffusion couple technique solid-state diffusion INTERDIFFUSION
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Brownian Motion of a Test Particle with a Normal Classical Velocity in Spacetime with a Plane Boundary 被引量:1
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作者 FU Xiang-Yun YU Hong-Wei 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第5期847-850,共4页
We study the random motion of a charged test particle with a normal classical constant velocity in a spacetime with a perfectly reflecting plane boundary and calculate both the velocity and position dispersions of the... We study the random motion of a charged test particle with a normal classical constant velocity in a spacetime with a perfectly reflecting plane boundary and calculate both the velocity and position dispersions of the test particle. Our results show that the dispersions in the normal direction are weakened while those in the parallel directions are strengthened as compared to the classical static case when the test particle classically moves away from the boundary. However, if the classical motion reverses its direction, then the dispersions in the normal direction are reinforced while those in the parallel directions get weakened. 展开更多
关键词 Brownian motion vacuum fluctuation quantum field theory
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非线性弹性转子-轴承系统稳定裕度数值分析 被引量:1
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作者 刘继华 陈立 +2 位作者 罗载奇 李奕新 钱兴良 《燃气涡轮试验与研究》 北大核心 2015年第6期39-44,共6页
基于互补群群际能量壁垒准则量化理论,提出了轨迹加速度-位移扩展相平面稳定裕度分析法,从理论分析、数值计算两方面验证了该方法的正确性。建立了采用Capone圆轴承非线性油膜力模型的弹性转子-轴承系统模型,并用数值积分和庞加莱映射方... 基于互补群群际能量壁垒准则量化理论,提出了轨迹加速度-位移扩展相平面稳定裕度分析法,从理论分析、数值计算两方面验证了该方法的正确性。建立了采用Capone圆轴承非线性油膜力模型的弹性转子-轴承系统模型,并用数值积分和庞加莱映射方法,得到系统在某些参数域中的分岔图、轴心轨迹图、庞加莱映射图、时间历程图和频谱图,得出分岔失稳速度随质量偏心的变化规律:分岔速度随质量偏心的趋势是先减小后增大,拟合曲线符合三次高斯公式,拟合精度达0.998 2。数值分析结果为该类转子-轴承系统的设计和安全运行提供了理论参考。 展开更多
关键词 旋转机械 转子-轴承系统 速度-位移扩展相平面 非线性 稳定裕度 分岔失稳转速 质量偏心
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Analyzing and Forecasting Climate Change in Harbin City,Northeast China 被引量:4
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作者 ZHANG Lijuan LIU Dong +3 位作者 YAN Xiaodong ZHOU Dongying ZHENG Hong SU Lianling 《Chinese Geographical Science》 SCIE CSCD 2011年第1期65-73,共9页
Based on sounding data from 1975 to 2005 and TM/ETM+ remote sensing images in 1989, 2001 and 2007, the climate changes in Harbin City, Northeast China in recent 30 years were analyzed and forecasted. Results show that... Based on sounding data from 1975 to 2005 and TM/ETM+ remote sensing images in 1989, 2001 and 2007, the climate changes in Harbin City, Northeast China in recent 30 years were analyzed and forecasted. Results show that in the lower troposphere the meridional wind speed and mean annual wind speed decrease, and in the lower stratosphere the temperature decreases while the meridional wind speed increases significantly. In the study area, the climate is becoming warmer and wetter in the middle lower troposphere. The expansion of urban area has great effects on the surface air temperature and the wind speed, leading to the increase of the surface air temperature, the decrease of the surface wind speed, and the increase of the area of urban high temperature zone. The quantitative equations have been established among the surface air temperature, the carbon dioxide (CO2) concentration and the specific humidity (the water vapor content). It is predicted that the future increasing rate of the surface air temperature is 0.85℃/10yr if emission concentration of CO2 remains unchanged; if emission concentration of CO2 decreases to 75%, 50% and 25%, respectively, the surface air temperature will increase 0.65℃/10yr, 0.46℃/10yr and 0.27℃/10yr, respectively. The rise of the surface air temperature in the study area is higher than that of the global mean temperature forecasted by IPCC. 展开更多
关键词 climate change climate forecast cause analysis Northeast China
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基于EEMD的验潮站水位序列降噪方法 被引量:3
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作者 戴国强 沈友东 贺小星 《海洋测绘》 CSCD 北大核心 2022年第2期1-5,共5页
验潮站水位序列是研究海平面变化的重要基础数据,针对验潮站水位序列中夹杂的噪声对海平面变化速度估计的负面影响,提出一种基于整体经验模态分解方法(EEMD)的降噪新方法。该方法通过EEMD进行水位序列分解,并以相关系数进行高频噪声与... 验潮站水位序列是研究海平面变化的重要基础数据,针对验潮站水位序列中夹杂的噪声对海平面变化速度估计的负面影响,提出一种基于整体经验模态分解方法(EEMD)的降噪新方法。该方法通过EEMD进行水位序列分解,并以相关系数进行高频噪声与低频信号分离,以提高验潮站水位序列速度估值的确定精度。通过对美国西海岸的10个长期验潮站进行实验分析,实验结果表明经本文所提出的方法降噪后的验潮站水位序列能清晰地反映站点长期的变化趋势,其海平面变化速度不确定度平均减小0.122 mm/年,并且在较高纬度地区效果更为显著。 展开更多
关键词 验潮站水位序列 平面变化速度 整体经验模态分解 降噪分析 速度不确定度
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A Study on a Vessel with Multiple Flat and Hard Sails to Keep Service Speed in High Winds
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作者 大西星輝 桃木勉 池田良穗 《Journal of Marine Science and Application》 2010年第2期143-148,共6页
Ships which have large structures above water surface,such as pure car carriers(PCCs) and container vessels,have large speed reduction by wind pressure.In the present study,the running speed of a large PCC with two or... Ships which have large structures above water surface,such as pure car carriers(PCCs) and container vessels,have large speed reduction by wind pressure.In the present study,the running speed of a large PCC with two or more sails for using wind power is simulated.The simulated results demonstrate that the ship can keep a constant service speed even in winds of 20m/s except head and bow winds.This sail system can shorten annual average navigation time by about 4 hours per voyage. 展开更多
关键词 pure car carrier (PCC) flat-plate sail oblique sailing vessel speed
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Modelling of Non-coaxial Viscoplastic Deformation in Geodynamics
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作者 Hans B. Muhlhaus Louise Olsen-Kettle +1 位作者 Jingyu Shi Louis Moresi 《Journal of Civil Engineering and Architecture》 2014年第8期1017-1025,共9页
The formation of shear bands for time and length scales appropriate for deformation processes in the upper Lithosphere is investigated in plane strain finite element simulations under predominantly uniaxial extension ... The formation of shear bands for time and length scales appropriate for deformation processes in the upper Lithosphere is investigated in plane strain finite element simulations under predominantly uniaxial extension and compression, respectively. The direction of gravity is assumed orthogonal to the extension/compression axis. Mathematically, the formation of shear zones may be explained as a consequence of changes in the type of the governing model equations. Such changes or bifurcations depend strongly on the details of the constitutive relationships such as strain softening, thermal or chemical effects, associated or non-associated--coaxial or non-coaxial flow rules. Here we focus on strain softening and coaxial and non-coaxial flow rules. In the simulations, we consider an initially rectangular domain with the dimensions Lo, Ho in the horizontal, vertical directions, respectively. The domain is extended or compressed by prescribing a uniform, horizontal velocity field along one of the vertical boundaries while keeping the opposite boundary fixed. An important global descriptor of the deformation process is the relationship between the horizontal stress resultant (average horizontal stress) and the strain ln(L/Lo), where L is the deformed length of the domain. The main goal of this paper is to investigate key factors influencing the phenomenology of the localization process such as flow rule, coaxial, non-coaxial and strain softening. Different origins of the mesh sensitivity of deformations involving localization are also investigated. 展开更多
关键词 Shearing band NON-COAXIALITY SOFTENING viscous plastic materials
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Global Distribution of Thermosteric Contribution to Sea Level Rising Trend 被引量:1
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作者 ZUO Juncheng DU Ling +1 位作者 ZHANG Jianli CHEN Meixiang 《Journal of Ocean University of China》 SCIE CAS 2010年第3期199-209,共11页
The sea level derived from TOPEX/Poseidon (T/P) altimetry data shows prominent long term trend and inter-annual variability. The global mean sea level rising rate during 1993-2003 was 2.9mm a^-1. The T/P sea level t... The sea level derived from TOPEX/Poseidon (T/P) altimetry data shows prominent long term trend and inter-annual variability. The global mean sea level rising rate during 1993-2003 was 2.9mm a^-1. The T/P sea level trend maps the geographical variability. In the Northern Hemisphere (15°-64°N), the sea level rise is very fast at the mid-latitude (20°-40°N) but much slower at the high-latitude, for example, only 0.5 mm a^-1 in the latitude band 40°-50°N. In the Southern Hemisphere, the sea level shows high rising rate both in mid-latitude and high-latitude areas, for example, 5.1 mm a^-1 in the band 40°- 50°S. The global thermosteric sea level (TSL) derived from Ishii temperature data was rising during 1993-2003 at a rate of 1.2 mm a^-1 and accounted for more than 40% of the global T/P sea level rise. The contributions of the TSL distribution are not spatially uniform; for instance, the percentage is 67% for the Northern Hemisphere and only 29% for the Southern Hemisphere (15°-64°S) and the maximum thermosteric contribution appears in the Pacific Ocean, which contributes more than 60% of the global TSL. The sea level change trend in tropical ocean is mainly caused by the thermosteric effect, which is different from the case of seasonal variability in this area. The TSL variability dominates the T/P sea level rise in the North Atlantic, but it is small in other areas, and shows negative trend at the high-latitude area (40°-60°N, and 50°-60°S). The global TSL during 1945-2003 showed obvious rising trend with the rate of about 0.3 mm a-l and striking inter-annual and decadal variability with period of 20 years. In the past 60 years, the Atlantic TSL was rising continuously and remarkably, contributing 38% to the global TSL rising. The TSL in the Pacific and Indian Ocean rose with significant in- ter-annual and decadal variability. The first EOF mode of the global TSL from Ishii temperature data was the ENSO mode in which the time series of the first mode showed steady rising trend. Among the three oceans, the first mode of the Pacific TSL presented the ENSO mode; there was relatively steady rising trend in the Atlantic Ocean, and no dominant mode in the Indian Ocean. 展开更多
关键词 thermosteric effect sea level trend T/P altimeter spatial distribution
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64层螺旋CT冠状动脉血管造影“一站式”二尖瓣环收缩期运动参数测量对左心室收缩功能不全的诊断价值
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作者 李旭文 杜秀娟 王夕富 《实用医学影像杂志》 2021年第5期452-455,共4页
目的研究二尖瓣环收缩期运动相关参数[二尖瓣环平面收缩期位移(MAPSE)、二尖瓣环平面收缩期移动速度(MAPSMV)、左心室长轴应变(LAS)]与左心室收缩功能的关系,评估64层螺旋CT冠状动脉血管造影“一站式”二尖瓣环收缩期运动相关参数测量... 目的研究二尖瓣环收缩期运动相关参数[二尖瓣环平面收缩期位移(MAPSE)、二尖瓣环平面收缩期移动速度(MAPSMV)、左心室长轴应变(LAS)]与左心室收缩功能的关系,评估64层螺旋CT冠状动脉血管造影“一站式”二尖瓣环收缩期运动相关参数测量对于左心室收缩功能不全的临床诊断价值。方法采用64层螺旋CT回顾性心电门控扫描技术对纳入研究的对照组(23名健康志愿者)、研究组(23例EF≥50%的左心室收缩功能不全患者)进行冠状动脉CTA检查,基于所获冠状动脉CTA图像数据测量2组二尖瓣环收缩期运动相关参数及左心室射血分数(LVEF),对2组间二尖瓣环收缩期运动相关参数及LVEF进行对比分析。结果研究组LVEF略低于对照组,二者间差异无统计学意义(t=1.42,P=0.16);研究组二尖瓣环收缩期位移(MAPSE)、二尖瓣环收缩期位移指数(MAPSEI)、二尖瓣环平面收缩期移动速度(MAPSMV)、二尖瓣环平面收缩期移动速度指数(MAPSMVI)、右心室长轴应变(LAS)参数低于对照组,2组间差异有统计学意义(P<0.05);MAPSE、MAPSEI、MAPSMV、MAPSMVI、LAS诊断EF≥50%左心室收缩功能不全的受试者工作特征曲线(ROC)曲线下面积分别为0.835、0.773、0.767、0.698、0.721,整体诊断准确性处于中到低水平。结论基于64层螺旋CT冠状动脉CTA的“一站式”二尖瓣环收缩期运动相关参数测量具有操作简单、重复性好的优点,可以在未额外增加X线辐射剂量及造影剂剂量前提下使受检者同时获得冠状动脉血管及左心室收缩功能相关信息,可以为诊断EF值尚处于正常范围的左心室收缩功能不全患者提供客观依据,在血管相关性射血分数保留型心力衰竭的诊断方面具有乐观的临床应用前景。 展开更多
关键词 二尖瓣环平面收缩期位移 左心室长轴应变 二尖瓣环平面收缩期移动速度 左心室收缩功能不全 冠状动脉CTA 一站式
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Effect of Moisture Content and Feed Rate on Size Reduction of Pearl Millet
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作者 S. Balasubramanian R. Sharma S. R. Vii ay Kumar 《Journal of Food Science and Engineering》 2011年第2期93-99,共7页
Pearl millet at various moisture content (6.2, 9.4 and 12.3%, d.b.) and feed rates (3, 6 and 9 kg/h) was ground using hammer mill and its physical properties viz. arithmetic mean diameter, geometric mean diameter,... Pearl millet at various moisture content (6.2, 9.4 and 12.3%, d.b.) and feed rates (3, 6 and 9 kg/h) was ground using hammer mill and its physical properties viz. arithmetic mean diameter, geometric mean diameter, thousand grain weight, aspect ratio, specific surface area, surface area and bulk density were studied. Sieve analysis results showed that the increase in moisture content produced more medium sized particles with decreased percent weight retained in pan. Bond's work index, Kick's constant and average particle size were increased with the decrease in total surface area at higher moisture levels. The highest energy (2.34 KWh/kg) was consumed for 12.3% moisture content. Various grinding characteristics were significantly affected by moisture content and feed rate either individually or in combination and correlated in terms of Bond's work index, Kick's constant, total surface area, average particle size, effectiveness of milling and bulk density. Milling loss was found to be higher at lower moisture level and decreased with the increase of moisture content as well as feed rate. The loose and compact bulk density was ranged between 46.8-199.5 kg m^-3and 53.5-254.1 kg m^-3, respectively among the entire sieve fractions. Water absorption capacity increased with the decrease in particle size, 展开更多
关键词 Pearl millet GRINDING size reduction particle size sieve analysis hammer mill moisture content.
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Directivity Effect on PGV Attenuation Relationships in Silakhor Earthquake (2006, Mw6.1)
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作者 Katayoun Behzadafshar Abbas Abbaszadeh Shahri 《Journal of Civil Engineering and Architecture》 2011年第12期1117-1125,共9页
Rupture directivity effect causes spatial variation in strong ground motion parameters. It causes difference between the strike- normal (V.) and strike-parallel (Vp) components of horizontal ground motion amplitud... Rupture directivity effect causes spatial variation in strong ground motion parameters. It causes difference between the strike- normal (V.) and strike-parallel (Vp) components of horizontal ground motion amplitudes. These variations become significant for strong ground motion velocity and the authors have developed a modification to define directivity effect factor to account for the effect of rupture directivity in empirical velocity attenuation relations which are based on modeling Silakhor earthquake, using finite element method by ANSYS. The ground motion parameters that are modified include ratio of Vn/Vp component of horizontal velocity and Vn component to average horizontal velocity (V). The ratio of Vn to Vp is large in both the forward directivity direction, where velocity is larger, and in the backward directivity direction, where velocity is smaller. Therefore the authors expected that the Vn/Vp was mainly controlled by directivity angle. Also the variation of fault normal velocity to average horizontal velocity ratio by directivity angle (0) is defined from earthquake modeling. It shows Vn/V is controlled by directivity angle, distance between the site, epicenter and rupture length. This ratio has the same trend in Silakhor earthquake strong ground velocity data. In this paper the equation for Vn/Vp variations by directivity angle is recommended. The authors used Somervill et al. (1997) directivity model parameters as (R/L) cos2 ~ to define directivity effect on Vn/V ratio and therefore directivity factor is determined to account in near field empirical strong ground velocity attenuation relationships. 展开更多
关键词 DIRECTIVITY Silakhor earthquake velocity attenuation relationships
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Analysis on Tectonic Movement of the Longmenshan Fault Zone before the Wenchuan M_S 8. 0 Great Earthquake
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作者 Ping Jianjun Jiang Zaisen +3 位作者 Feng Xiangdong Ping Caipeng Shan Lianjun Wang Xia 《Earthquake Research in China》 2014年第3期299-310,共12页
On the basis of elastic rebound theory,using the horizontal velocity field of the Chinese mainland calculated from GPS data during three observation periods from 1999 to 2007,the velocity components that are parallel ... On the basis of elastic rebound theory,using the horizontal velocity field of the Chinese mainland calculated from GPS data during three observation periods from 1999 to 2007,the velocity components that are parallel and plumb to the fault zone are calculated respectively for different periods,and then relative ground movements of two sides of the fault zone are analyzed with power function fitting and graphics. The results show that the relative ground movement shows right-lateral shear deformation before the Wenchuan MS8. 0 earthquake,and at the same time the movement was hindered by the Longmenshan fault zone. Thus,this result has positive significance for distinguishing the elastic strain energy accumulation and deformation anomaly in an earthquake preparation process,and for conducting further research on earthquake prediction. 展开更多
关键词 LONGMENSHAN GPS Right-lateral shear Elastic strain The WenchuanMs8. 0 earthquake
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胶囊机器人在小肠内启动的动力学分析 被引量:1
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作者 谭人嘉 刘浩 +1 位作者 李洪谊 王越超 《信息与控制》 CSCD 北大核心 2015年第5期552-556,共5页
针对目前胶囊机器人的运动与小肠的材料力学特性之间尚未建立数量关系的问题进行了研究.以和胶囊内窥镜外形相似的"内力—摩擦"式胶囊机器人为例,基于连续介质力学理论,结合五元件粘弹性模型,建立了其在肠道中运动的动力学方... 针对目前胶囊机器人的运动与小肠的材料力学特性之间尚未建立数量关系的问题进行了研究.以和胶囊内窥镜外形相似的"内力—摩擦"式胶囊机器人为例,基于连续介质力学理论,结合五元件粘弹性模型,建立了其在肠道中运动的动力学方程;采用前期的五元件模型参数实验测量结果,在"速度—位移"相平面上,定量且直观地解释了驱动力的给力方式对胶囊启动过程的影响. 展开更多
关键词 胶囊机器人 动力学 速度—位移”相平面 粘弹性
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An in-plane low-noise accelerometer fabricated with an improved process flow 被引量:3
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作者 Xu-dong ZHENG Zhong-he JIN Yue-lin WANG Wei-jun LIN Xiao-qi ZHOU 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2009年第10期1413-1420,共8页
We present a bulk micromachined in-plane capacitive accelerometer fabricated with an improved process flow,by etching only one-fifth of the wafer thickness at the back of the silicon while forming the bar-structure el... We present a bulk micromachined in-plane capacitive accelerometer fabricated with an improved process flow,by etching only one-fifth of the wafer thickness at the back of the silicon while forming the bar-structure electrode for the sensing capacitor.The improved flow greatly lowers the footing effect during deep reactive ion etching(DRIE),and increases the proof mass by 54% compared to the traditional way,resulting in both improved device quality and a higher yield rate.Acceleration in the X direction is sensed capacitively by varying the overlapped area of a differential capacitor pair,which eliminates the nonlinear behavior by fixing the parallel-plate gap.The damping coefficient of the sensing motion is low due to the slide-film damping.A large proof mass is made using DRIE,which also ensures that dimensions of the spring beams in the Y and Z directions can be made large to lower cross axis coupling and increase the pull-in voltage.The theoretical Brownian noise floor is 0.47 μg/Hz1/2 at room temperature and atmospheric pressure.The tested frequency response of a prototype complies with the low damping design scheme.Output data for input acceleration from ?1 g to 1 g are recorded by a digital multimeter and show very good linearity.The tested random bias of the prototype is 130 μg at an averaging time of around 6 s. 展开更多
关键词 MEMS accelerometer Deeo reactive ion etchin (DRIE) Footin effect Canacitive sensing
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Vertical motions of tide gauge stations near the Bohai Sea and Yellow Sea 被引量:4
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作者 LIU ShouHua CHEN ChangLin +6 位作者 LIU KeXiu MU Lin WANG Hui WU XinRong ZHANG JianLi DUAN XiaoFeng GAO Jia 《Science China Earth Sciences》 SCIE EI CAS CSCD 2015年第12期2279-2288,共10页
A modified Gauss-Markov model with weighted constraints was constructed by combining satellite altimeter and tide gauge records. Vertical motion rates of nine tide gauge stations around the Bohal Sea and Yellow Sea ar... A modified Gauss-Markov model with weighted constraints was constructed by combining satellite altimeter and tide gauge records. Vertical motion rates of nine tide gauge stations around the Bohal Sea and Yellow Sea are estimated. This is the first time systematic estimates have been derived in this region. Downward trends were seen at the six tide gauge stations located at Tanggu, Longkou, Laohutan, Bayuquan, Xiaochangshan, and Yantai; with vertical motion rates of-1.82±0.50, -1.65±0.46, -0.88±0.42, -0.58±0.62, -0.13±0.43, and -0.01±0.43 mm/yr, respectively. Upward trends were seen at the three tide gauge stations located at Qinhuangdao, Huludao and Chengshantou; with vertical motion rates of 1.12±0.46, 0.55±0.49 and 0.26±0.44 mm/yr, respectively. There was significant subsidence in Tanggu and Longkou, and a rising trend in Qinhuangdao. According to our results, the rate of sea level rise calculated from these tide gauge records can be improved using a more accurate measurement of the land elevation accounting for lifting or subsidence. The model derived can be used to estimate vertical motions of tide gauge stations, and can be widely applied to revise the benchmark levels of tide gauges. 展开更多
关键词 tide gauge station vertical ground motion sea level ALTIMETER Gauss Markov model
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