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英语时体本质的语言时间时轴分析 被引量:4
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作者 曾立 彩吟 《外语教学》 北大核心 2002年第6期45-49,共5页
英语中时直接反映的并非自然时间而是本文提出的语言时间。依据语言时间构想 ,作者设计了语言时间时轴并把它用于分析英语时体本质 ,得出了关于时体的新定义以及包含两时 (过去时与现在时 )四体 (一般体、进行体、完成体与将来体 )的英... 英语中时直接反映的并非自然时间而是本文提出的语言时间。依据语言时间构想 ,作者设计了语言时间时轴并把它用于分析英语时体本质 ,得出了关于时体的新定义以及包含两时 (过去时与现在时 )四体 (一般体、进行体、完成体与将来体 )的英语时体新分类体系。新体系揭示了英语时体结构固有的高度规律性与有序性 ,同时也证明了新体系赖以构建的语言时间原则具有较强的归纳力与解释力。 展开更多
关键词 自然时间 语言时间 时轴
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基于光学时轴校准MRI数据重建的高时空分辨率神经成像 被引量:2
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作者 邓梁 史仪凯 张均田 《神经药理学报》 2011年第3期47-54,共8页
功能核磁共振成像(functional magnetic resonance imaging,fMRI)是一种重要的生物医学成像和神经科学研究的手段。然而,空间分辨率低、时间分辨率低以及信噪比低仍然限制了其实际研究应用。本文提出了一种高时空分辨率的图像重建方法,... 功能核磁共振成像(functional magnetic resonance imaging,fMRI)是一种重要的生物医学成像和神经科学研究的手段。然而,空间分辨率低、时间分辨率低以及信噪比低仍然限制了其实际研究应用。本文提出了一种高时空分辨率的图像重建方法,实现光信息同步磁共振技术扫描脑皮层神经活动产生的血氧动态响应,时分式覆盖k空间数据(time division coverage,TDC)。同时也提出一种波长参数化指数平均滤波波长调制光谱法(PEMA-WMS)实现实时脑皮层血氧动态光学传感。实验给出了在预实验磁共振图像作为高空间分辨率组织层的光子流传感蒙特卡罗模拟方法和视觉皮层功能成像仿真,并得出本文方法的图像重建结果。 展开更多
关键词 高时空分辨率 磁共振成像 图像重建 光学传感 时轴校准 波长调制光谱法
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单相三轴法与单轴三相法的等价性
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作者 程小华 《防爆电机》 2023年第6期1-3,共3页
严格论证了三相交流系统中相量图两种画法即三轴法和单轴法的等价性。
关键词 三相交流系统 相量 时轴 投影 单相三轴法(三轴法) 单轴三相法(单轴法)
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基于AR模型的基因芯片数据识别 被引量:5
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作者 刘敬伟 程乾生 《生物数学学报》 CSCD 2003年第3期328-332,共5页
将自回归模型(AR)模型引入基因芯片数据识别领域,提出了基于自回归模型的时间序列特征提取方法。利用动态时轴弯曲(DTW)作为分类器,在标准的肿瘤基因芯片数据的识别结果表明,本方法能够达到100%的识别率,可以应用于基因芯片数据的识别... 将自回归模型(AR)模型引入基因芯片数据识别领域,提出了基于自回归模型的时间序列特征提取方法。利用动态时轴弯曲(DTW)作为分类器,在标准的肿瘤基因芯片数据的识别结果表明,本方法能够达到100%的识别率,可以应用于基因芯片数据的识别、分类和基因疾病推断。 展开更多
关键词 自回归模型 基因芯片 基因识别 动态时轴弯曲
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秘响旁通——中国美学的现代诠释 被引量:1
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作者 潘知常 《南京社会科学》 CSSCI 1993年第3期85-87,73,共4页
古典诗歌中的意象问题,在我国古代中是一个老问题。 “意象”一语,出自《易传·系辞(上)》:“子曰:圣人立象以尽意”。早在魏晋时代,刘勰孰总结了我国文艺创作的实践,提出了“窥意象而运斤”的看法。尔后,“意象”一词就作为成熟的... 古典诗歌中的意象问题,在我国古代中是一个老问题。 “意象”一语,出自《易传·系辞(上)》:“子曰:圣人立象以尽意”。早在魏晋时代,刘勰孰总结了我国文艺创作的实践,提出了“窥意象而运斤”的看法。尔后,“意象”一词就作为成熟的概念,广泛地出现于各家诗歌、论著中,象“意象欲出,造化已奇,”(司空图《诗品》)“久用精思,末契意象,……心偶照境,率然而尘”(王昌龄《诗格》)等。但是,由于某种原因,过去几十年我们只注意了对“意境”的研究,却忽视了对意象问题的探讨。结果,“门外青山人屋里,东家流水人西家”,倒是西方的一些有智之士,借鉴了这一珍贵遗产,形成了“意象派”。近年来,“意象”理论被介绍到国内,举国学界为之一振,研究文章亦随之而出,终于打破了沉寂的局面。 展开更多
关键词 “意象” 中国美学 秘响旁通 现代诠释 共时 语言文字 大家族 诗歌 诗僧 时轴
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高斯光束菲涅耳圆孔衍射轴上的光强分布 被引量:2
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作者 魏计林 阎柯柱 《大学物理》 1988年第3期16-18,共3页
本文从惠更斯-菲涅耳原理的数学表达式出发,在菲涅耳圆孔衍射的情况下求出了高斯光束入射时轴上光强分布的解析表达式,并对比平面波和球面波入射的情况进行了分折讨论.
关键词 菲涅耳圆孔衍射 光强分布 高斯光束 球面波 时轴 波带片 观察屏 倾斜因子 衍射屏 曲率半径
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油封漏油的原因预防
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作者 张鼎明 《江苏农机化》 1994年第2期29-30,共2页
一、原因 1、拆的或大修后的拖拉机没有严格按照磨合试运转的规范进行,使机器运转时磨削下来的铁屑进入油封里.引起磨料磨损,导致油封早期损坏,产生漏油。 2、安装时不注意清洁,将机械杂质混杂在油封里,使油封磨损。 3、安装时轴上有较... 一、原因 1、拆的或大修后的拖拉机没有严格按照磨合试运转的规范进行,使机器运转时磨削下来的铁屑进入油封里.引起磨料磨损,导致油封早期损坏,产生漏油。 2、安装时不注意清洁,将机械杂质混杂在油封里,使油封磨损。 3、安装时轴上有较深的沟痕,或轴与油封配合紧度不够。 4、装配时油封的的橡皮唇边残缺、老化或唇口有缺陷,或在装配中敲击时着力点不对,榔头敲击骨架油封受力不均,极易使油封骨架变形,以致整个油封变形。任何一个变形的油封装上后,绝对不能保证与轴颈有良好的配合,不仅加速油封的磨损。 展开更多
关键词 油封 试运转 机械杂质 唇口 机器运转 磨料磨损 沟痕 紧度 时轴 定期保养
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Just-in-time learning based integrated MPC-ILC control for batch processes 被引量:4
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作者 Li Jia Wendan Tan 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第8期1713-1720,共8页
Considering the two-dimension(2 D) characteristic and the unknown optimal trajectory problem of the batch processes, an integrated model predictive control-iterative learning control(MPC-ILC) for batch processes is pr... Considering the two-dimension(2 D) characteristic and the unknown optimal trajectory problem of the batch processes, an integrated model predictive control-iterative learning control(MPC-ILC) for batch processes is proposed in this paper. Firstly, the batch-axis information and time-axis information are combined into one quadratic performance index. It implies the integration of ILC and MPC algorithm idea, which leads to superior tracking performance and better robustness against disturbance and uncertainty. To address the problem of the unknown optimal trajectory, both time-varying prediction horizon and end product quality control are employed. Moreover, an integrated 2 D just-in-time learning(JITL) model is used to improve the predictive accuracy. Furthermore, rigorous description and proof are presented to prove the convergence and tracking performance of the proposed MPC-ILC strategy. The simulation results show the effectiveness of the proposed method. 展开更多
关键词 Model predictive control Batch process Just-in-time learning (JITL) model
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Simultaneous measurement of phase retardation and optic axis of wave plates 被引量:3
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作者 ZHANG Xu WU Fu-quan WANG Hai-long YAN Bin KONG Chao 《Optoelectronics Letters》 EI 2007年第1期65-68,共4页
A simple method used for simultaneous measurement of phase retardation and optic axis of wave plate by employing 1/4 wave plate is demonstrated. The theoretical analysis of the measuring principle is presented in deta... A simple method used for simultaneous measurement of phase retardation and optic axis of wave plate by employing 1/4 wave plate is demonstrated. The theoretical analysis of the measuring principle is presented in detail. In the measurement, after adjusting a standard 1/4 wave plate and the fast (slow) axis of the plate to be measured parallel to the pass axis of the polarizer, the plate to be measured is rotated by 450 counterclockwisly. A stepping motor is used to rotate the analyzer. The experimental data are collected by a photodetector and then sent to a computer. According to the output data curve, the phase retardation and optic axis of the plate to be measured can be obtained simultaneously. To test the feasibility of the method, a λ /2 and a λ /8 wave plates are used as examples to demonstrate the measurement procedures. The phase retardation measurement accuracy is better than 0.5×10-2. This method can be used to measure the arbitrary phase retardation conveniently. 展开更多
关键词 波片 相位推延 光轴 同时测量 极化态
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Integrated identification method of rheological model of sandstone in Sanmenxia bauxite
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作者 张春阳 曹平 +2 位作者 蒲成志 刘杰 文丕华 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第6期1859-1865,共7页
Based on the uniaxial compression creep experiments conducted on bauxite sandstone obtained from Sanmenxia,typical creep experiment curves were obtained.From the characteristics of strain component of creep curves,the... Based on the uniaxial compression creep experiments conducted on bauxite sandstone obtained from Sanmenxia,typical creep experiment curves were obtained.From the characteristics of strain component of creep curves,the creep strain is composed of instantaneous elastic strain,ε(me),instantaneous plastic strain,ε(mp),viscoelastic strain,ε(ce),and viscoplastic strain,ε(cp).Based on the characteristics of instantaneous plastic strain,a new element of instantaneous plastic rheology was introduced,instantaneous plastic modulus was defined,and the modified Burgers model was established.Then identification of direct screening method in this model was completed.According to the mechanical properties of rheological elements,one- and three-dimensional creep equations in different stress levels were obtained.One-dimensional model parameters were identified by the method of least squares,and in the process of computation,Gauss-Newton iteration method was applied.Finally,by fitting the experimental curves,the correctness of direct method model was verified,then the examination of posterior exclusive method of the model was accomplished.The results showed that in the improved Burgers models,the rheological characteristics of sandstone are embodied properly,microscopic analysis of creep curves is also achieved,and the correctness of comprehensive identification method of rheological model is verified. 展开更多
关键词 uniaxial compression creep experiments instantaneous plastic rheological model element improved Burgers model direct screening method posterior exclusive method
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Rules for confidence intervals of permeability coefficients for water flow in over-broken rock mass 被引量:7
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作者 Liu Weiqun Fei Xiaodong Fang Jingnian 《International Journal of Mining Science and Technology》 2012年第1期29-33,共5页
Based on the steady-state seepage method, we used the Mechanical Testing and Simulation 815.02 System and a self-designed seepage instrument for over-broken stone to measure seepage properties of water flows in three ... Based on the steady-state seepage method, we used the Mechanical Testing and Simulation 815.02 System and a self-designed seepage instrument for over-broken stone to measure seepage properties of water flows in three types of crushed rock samples. Three methods of confidence interval in describing permeability coefficients are presented: the secure interval, the calculated interval and the systemic interval. The lower bound of the secure interval can be applied to water-inrush and the upper bound can solve the problem of connectivity. For the calculated interval, as the axial pressure increases, the length of confidence interval is shortened and the upper and lower bounds are reduced. For the systemic interval, the length of its confidence interval, as well as the upper and lower bounds, clearly vary under low axial pressure but are fairly similar under high axial pressure. These three methods provide useful information and references for analyzing the permeability coefficient of over-broken rock. 展开更多
关键词 Over-broken rock mass Permeability coefficient Secure interval Calculated interval Systemic interval
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College Coaching Legends
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作者 Xue Yang Jiwei Jin 《Sociology Study》 2016年第10期676-681,共6页
Everyone has his heroes, like the college coaches, many of them play a important role in our college life, and they hve a legendary life here at the same time. In America, college student pay attention to NCAA (Natio... Everyone has his heroes, like the college coaches, many of them play a important role in our college life, and they hve a legendary life here at the same time. In America, college student pay attention to NCAA (National Collegiate Athletic Association), there are many famous coaches in it, such as Nich Saban, Jerry Tarkanian, and more. The authors are very interested in the competitive life of those who are the top five coaches in the world. So the authors concentrate on the winning rate, the contribution rate, and the cycle of the honors to evaluate each coach, by standardizing the metrics, they get the final scores of each metric for basketball; according to the scores, they get the top five coaches in a century. And in this paper, the authors also take the gender and timeline into account. 展开更多
关键词 Standardization of the dispersion coefficient of variation method weighted arithmetic mean of comprehensive evaluation
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Development of timer based on liquid level measurement system
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作者 Banajit Chakraborty T K Maiti 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2016年第4期383-387,共5页
This paper describes the design and development of the timer based on liquid level measurement system in which timer 555 is used in astable mode. The capacitor charging time i. e. the ON time pulse width of the ti... This paper describes the design and development of the timer based on liquid level measurement system in which timer 555 is used in astable mode. The capacitor charging time i. e. the ON time pulse width of the timer output waveform which is measured using a digital storage oscillator (DSO),is linearly proportional to the capacitance of a co-axial cylindrical capacitive transducer, and this capacitance once again linearly varies with the change in liquid level. Hence, we obtain a linear relationship between the liquid level and the capacitor charging time. The main advantages of this developed system are linear input-output relationship, small in size, easily portable, cost effective, and independent on the ambient temperature effect. The system can also be exploited to measure dielectric constant of liquid or solid in various process industries. 展开更多
关键词 timer IC555 liquid level measurement system capacitor charging time co-axial cylindrical capacitive transducer
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Micro-failure process and failure mechanism of brittle rock under uniaxial compression using continuous real-time wave velocity measurement 被引量:3
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作者 WU Zhi-jun WANG Zhi-yang +2 位作者 FAN Li-feng WENG Lei LIU Quan-sheng 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第2期556-571,共16页
In this study,the micro-failure process and failure mechanism of a typical brittle rock under uniaxial compression are investigated via continuous real-time measurement of wave velocities.The experimental results indi... In this study,the micro-failure process and failure mechanism of a typical brittle rock under uniaxial compression are investigated via continuous real-time measurement of wave velocities.The experimental results indicate that the evolutions of wave velocities became progressively anisotropic under uniaxial loading due to the direction-dependent development of micro-damage.A wave velocity model considering the inner anisotropic crack evolution is proposed to accurately describe the variations of wave velocities during uniaxial compression testing.Based on which,the effective elastic parameters are inferred by a transverse isotropic constitutive model,and the evolutions of the crack density are inversed using a self-consistent damage model.It is found that the propagation of axial cracks dominates the failure process of brittle rock under uniaxial loading and oblique shear cracks develop with the appearance of macrocrack. 展开更多
关键词 elastic wave velocity brittle rock failure uniaxial compression test continuous real-time measurement anisotropic damage evolution theory and modelling
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Advanced tufted carpet patterning technology 被引量:1
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作者 赵越 戴惠良 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第3期374-377,共4页
After a review of the tufting industry’s development, and a brief introduction to available systems for producing patterned tufted carpets, the principle of ICN (Individually Controlled Needle) and the related advanc... After a review of the tufting industry’s development, and a brief introduction to available systems for producing patterned tufted carpets, the principle of ICN (Individually Controlled Needle) and the related advanced tufting technology Col-ortec are presented. Finally, Colortec machine, Axminster weaving machine, and Wilton loom are compared. It is believed that the Cobble Colortec machine is a significant jump forward in the tufted carpets industry as it now allows access to all major carpet markets in a competitive fashion. 展开更多
关键词 Tufting PATTERNING Sliding needlebar Colortec Creel SCROLL
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Effects of axial static stress on stress wave propagation in rock considering porosity compaction and damage evolution 被引量:7
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作者 JIN Jie-fang YUAN Wei +1 位作者 WU Yue GUO Zhong-qun 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第2期592-607,共16页
A wave equation of rock under axial static stress is established using the equivalent medium method by modifying the Kelvin-Voigt model.The analytical formulas of longitudinal velocity,space and time attenuation coeff... A wave equation of rock under axial static stress is established using the equivalent medium method by modifying the Kelvin-Voigt model.The analytical formulas of longitudinal velocity,space and time attenuation coefficients and response frequency are obtained by solving the equation using the harmonic method.A series of experiments on stress wave propagation through rock under different axial static stresses have been conducted.The proposed models of stress wave propagation are then verified by comparing experimental results with theoretical solutions.Based on the verified theoretical models,the influences of axial static stress on longitudinal velocity,space and time attenuation coefficients and response frequency are investigated by detailed parametric studies.The results show that the proposed theoretical models can be used to effectively investigate the effects of axial static stress on the stress wave propagation in rock.The axial static stress influences stress wave propagation characteristics of porous rock by varying the level of rock porosity and damage.Moreover,the initial porosity,initial elastic modulus of the rock voids and skeleton,viscous coefficient and vibration frequency have significant effects on the P-wave velocity,attenuation characteristics and response frequency of the stress wave in porous rock under axial static stress. 展开更多
关键词 stress wave propagation axial static stress porosity compaction space and time attenuation response frequency
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The green hydrolysis technology of hemicellulose in corncob by the repeated use of hydrolysate 被引量:2
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作者 Lei Guo Yangdong Hu +2 位作者 Lianying Wu Chen Liang Weitao Zhang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第1期191-195,共5页
To achieve green hydrolysis technology of hemicellulose through repeated using hydrolysate, the hydrolysis of hemicellulose in corncob was studied. The influence of repeated use of corncob hydrolysate on concentration... To achieve green hydrolysis technology of hemicellulose through repeated using hydrolysate, the hydrolysis of hemicellulose in corncob was studied. The influence of repeated use of corncob hydrolysate on concentrations of D-xylose and L-arabinose was investigated. The loss rates of D-xylose in the prepared D-xylose solutions both with and without corncob, and repeated using corncob hydrolysate under identical acidity condition were discussed. The result shows that D-XyIOSe concentration and L-arabinose concentration are all gradually increas- ing with the growing time of repeated use of corncob hydrolysate. After the fifth repetition, the concentrations of D-xylose and L-arabinose are 196.7 g. L-1 and 22.0 g.L-1, respectively. Substance inhibiting the degradation of D-xylose is generated during repeated use of corncob hydrolysate, and the production is further proved by the change of D-xylose concentration and the loss rate of D-xylose over heating time. 展开更多
关键词 D-xylose Repeatedly-using hydrolysate Acidolysis Water-saving Acid-saving
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Efficient Path Query and Reasoning Method Based on Rare Axis
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作者 姜洋 冯志勇 +1 位作者 王鑫 马晓宁 《Transactions of Tianjin University》 EI CAS 2015年第3期278-283,共6页
A new concept of rare axis based on statistical facts is proposed, and an evaluation algorithm is designed thereafter. For the nested regular expressions containing rare axes, the proposed algorithm can reduce its eva... A new concept of rare axis based on statistical facts is proposed, and an evaluation algorithm is designed thereafter. For the nested regular expressions containing rare axes, the proposed algorithm can reduce its evaluation complexity from polynomial time to nearly linear time. The distributed technique is also employed to construct the navigation axis indexes for resource description framework(RDF) graph data. Experiment results in Drug Bank and Bio GRID show that this method can improve the query efficiency significantly while ensuring the accuracy and meet the query requirements on Web-scale RDF graph data. 展开更多
关键词 GRAPH PATH regular expression COMPLEXITY distribution
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Experimental and Analytical Study of Torsional Vibration under Multiaxial Loading in Time Domain
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作者 Dionisio Jose Rodrigues da Costa Ladario da Silv +1 位作者 Jorge Rodrigues Duran Jose Flavio Feiteira 《Journal of Mechanics Engineering and Automation》 2016年第3期148-157,共10页
The torsional vibration of power transmission shaft is a phenomenon whose analytical modeling can be represented by a differential equation of motion proposed by technical literature. The solutions of these equations ... The torsional vibration of power transmission shaft is a phenomenon whose analytical modeling can be represented by a differential equation of motion proposed by technical literature. The solutions of these equations need coefficients and parameters that, usually, must be experimentally estimated. This work uses a resistive electric SG (strain gage) to dynamically determine strains produced in the shaft due to harmonic oscillatory motion under multiaxial loading. This movement is simulated on a prototype specially developed for this purpose. It comprises a pulley attached to the end of a stepped cantilevered shaft, which is clamped at the opposite end. In this configuration, a cam generates a torque to the system, springs regulate the stiffness and the damping coefficient of the assembly, as well as they can be suitably adjusted to produce an underdamped condition. The main advantage, highlighted in this study, refers to a major simplification. Although the system under study shows multiple degrees of freedom (torsion and bending), the shape and the positioning of linking SGs with the resistor bridge (Wheatstone Bridge), allow "to evaluate the loading effects independently, as if only one degree of freedom of the system exists at a time domain. Strains graphs for two forms of cyclic torsional oscillation, analytical and experimental, were successfully generated. 展开更多
关键词 Underdamped system free and forced response torsional vibration strain gauges.
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Grain crushing and its effects on rheological behavior of weathered granular soil
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作者 陈晓斌 张家生 《Journal of Central South University》 SCIE EI CAS 2012年第7期2022-2028,共7页
To disclose the grain crushing effects on the weathered granular soil rheological behavior,a series of rheological tests (odometer compression and triaxial shearing) were carried out.At the same time,the sieving analy... To disclose the grain crushing effects on the weathered granular soil rheological behavior,a series of rheological tests (odometer compression and triaxial shearing) were carried out.At the same time,the sieving analysis tests of these specimens were also executed before and after tests,and the grain crushing degree,Br and n5,were collectively adopted to estimate the grain crushing.The grain crushing degree depends on the stress path,stress level,and load time,especially,the longer load time and more intensive gradient shearing path will increase the grain crushing quantity.The Hardin crushing degrees Br are 0.191,0.118 and 0.085 in the ordinary compression,rheological compression and triaxial rheological shearing,respectively;The grain crushing degrees n5 are 1.9,1.4 and 1.32,respectively.The strain softening phase indicates the grain crushing and diffusive collapse,and the strain hardening phase indicates the rearrangement of these crushed grains and formation of new bearing soil skeleton.The rheological deformation of granular soil can be attributed to the coarse grain crushing and the filling external porosity with crushed fragments. 展开更多
关键词 grain crushing degree rheological behavior weathered granular soil tri-axial rheological tests odometer compressiontest
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