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961.
ALIAmirIbrahim QINDa-tong ATTIANabilAbdulla 《重庆大学学报(英文版)》2004,3(2):38-42
In recent years, the sustainable development of automatic manual transmissions (AMTs) control in vehicles is conspicuous. The control applications have grown fast and steadily due to the tremendous progress in power electronics components and the control software that enhance the requirements for delivering higher vehicles performance. AMTs control strategies achieve a reduction in the driveline dynamic oscillations behavior during gear shifting and clutch starting up processes. AMTs future expectations are an increase of torque capacity, more speed ratios and the development of advanced and efficient electronic control systems. This paper concerns with the progressing view of AMTs in the past, today and future, gives an overview of the potential dynamic problems concerned with AMTs and some control strategies used to solve those problems. 相似文献
962.
Bor-Chen Kuo Chen-Huei Liao Kai-Chih Pai Shu-Chuan Shih Cheng-Hsuan Li Magdalena Mo Ching Mok 《教育心理学》2020,40(9):1164-1185
AbstractThe current study explores students’ collaboration and problem solving (CPS) abilities using a human-to-agent (H-A) computer-based collaborative problem solving assessment. Five CPS assessment units with 76 conversation-based items were constructed using the PISA 2015 CPS framework. In the experiment, 53,855 ninth and tenth graders in Taiwan were recruited, and a multidimensional item response analysis was used to develop CPS scales and represent the students’ collaboration and problem solving performance. The results show that the developed H-A approach is feasible for measuring students’ CPS skills, and the CPS scales are also shown to be reliable. In addition, the students’ CPS performance scores are further explored and discussed under the PISA CPS framework. 相似文献
963.
本文讨论了卵泡生长发育的动态模式,包括吸收、选择、优势化、退化或者排卵;并对在卵泡发生期间的调控和激素的作用机理也进行了综述。 相似文献
964.
In order to constitute engineering design methods of the flat ribbon wound explosion containment vessels, the dynamic response of such vessels subjected to internal explosion loading is simulated using LS-DYNA3D. Three winding angles, 10°, 15°and 20°, are considered. It is shown that among ribbon vessels investigated, the center displacement of outermost ribbons of the vessel with 10°winding angle is the smallest under the same blast loading. The response of vessels loaded in inner core is local. From the center of the cylindrical shell to the bottom cover, the maximum strain gradually decreases. The ribbons are subjected to tension in the length direction and compression in the width direction. Blasting shock energy concentrates on where is close to center section of blasting. For comparison, numerical simulation of a monobloc thick-walled explosion containment vessel is also investigated. It can be found that the biggest deformation of the flat ribbon wound explosion containment vessels is bigger than that of the monobloc thick-walled explosion containment vessel in the center section of blasting under the same TNT. Numerical results are approximately in agreement with experimental ones. It is proved that the ribbon vessels have the valuable properties of " leak before burst at worst" compared with the monobloc vessels through numerical simulation. 相似文献
965.
The effect of axial shallow groove on the nonlinear dynamic response and buckling of laminated cylindrical shells subjected to radial compression loading was investigated. Based on the first-order shear deformation theory (FSDT), the nonlinear dynamic equations involving the transverse shear deformation and initial geometric imperfections were derived with the Hamilton philosophy. The axial shallow groove of the laminated composite cylindrical shell was treated as the initial geometric imperfections in the dynamic equations. A semi-analytical method of expanding displacements and loads along the circumferential direction and employing the finite difference method along the axial direction and in the time domain is used to solve the governing equations and obtain the dynamic response of the laminated shell. The B-R criterion was employed to determine the critical loads of dynamic buckling of the shell. The effects of the parameters of the shallow groove on the dynamic response and buckling were discussed in this paper and the results show that the axial shallow grooves greatly affect the dynamic response and buckling. 相似文献
966.
本构造一种新的教学评估方法:以学生为主体,结合实验课教学的特点,适当运用测试的手段,动态评估实验课教学质量。 相似文献
967.
Patrick J. Curran Veronica Cole Daniel J. Bauer Andrea M. Hussong Nisha Gottfredson 《Structural equation modeling》2016,23(6):827-844
A challenge facing nearly all studies in the psychological sciences is how to best combine multiple items into a valid and reliable score to be used in subsequent modeling. The most ubiquitous method is to compute a mean of items, but more contemporary approaches use various forms of latent score estimation. Regardless of approach, outside of large-scale testing applications, scoring models rarely include background characteristics to improve score quality. This article used a Monte Carlo simulation design to study score quality for different psychometric models that did and did not include covariates across levels of sample size, number of items, and degree of measurement invariance. The inclusion of covariates improved score quality for nearly all design factors, and in no case did the covariates degrade score quality relative to not considering the influences at all. Results suggest that the inclusion of observed covariates can improve factor score estimation. 相似文献
968.
Thevibrationinducedbyiceisanimportantfactorofdamageforjacketplatforms ,sotheiceloadshavebeenthecontrolloadforjacketplatformsintheBohaiBay[1] .Toreducedamageinducedbytheiceforce ,theloadsstandardofjacketplatformshasbeenimproved .Infact ,thestrengthofjacketplatformsagainststaticiceforceismeteasily .But,thesafetyproblemoftheplatformaf fectedbyboththebehaviorsofself excitedandcouplingissolvedbyothertechnologysolutions[2— 3] .Xuetalde signedasetofdevicesforreducingvibrationofthejacketplatforminth… 相似文献
969.
INTRODUCTIONTheimpactonpiles bridgestructuresbymovingshipsorotherdriftingobjectsoftende stroysthebridge,soitisimportanttostudythe 相似文献
970.
The present study conducted a systematic review of the item response theory (IRT) literature in language assessment to investigate the conceptualization and operationalization of the dimensionality of language ability. Sixty-two IRT-based studies published between 1985 and 2020 in language assessment and educational measurement journals were first classified into two categories based on a unidimensional and multidimensional research framework, and then reviewed to examine language dimensionality from technical and substantive perspectives. It was found that 12 quantitative techniques were adopted to assess language dimensionality. Exploratory factor analysis was the primary method of dimensionality analysis in papers that had applied unidimensional IRT models, whereas the comparison modeling approach was dominant in the multidimensional framework. In addition, there was converging evidence within the two streams of research supporting the role of a number of factors such as testlets, language skills, subskills, and linguistic elements as sources of multidimensionality, while mixed findings were reported for the role of item formats across research streams. The assessment of reading, listening, speaking, and writing skills was grounded within both unidimensional and multidimensional framework. By contrast, vocabulary and grammar knowledge was mainly conceptualized as unidimensional. Directions for continued inquiry and application of IRT in language assessment are provided. 相似文献