排序方式: 共有75条查询结果,搜索用时 15 毫秒
41.
J. T. Yang H. Y. Choi J. H. Lee S. U. Lee 《International Journal of Automotive Technology》2014,15(4):667-672
An empirical analysis was performed in order to examine whether the height of the lumbar support installed on the driver’s seat in a vehicle makes a difference to the initial discomfort when sitting, and among the design variables of the seat lumbar support, which one is the main variable that affects the initial discomfort most when sitting. The subjects who participated in this study were 50th percentile male in their 30s and 40s from Korea and America, had driving experience, and had not experienced any back pain in the last 12 months. In order to figure out the level of discomfort felt by a driver depending on the movement or the shapes of the lumbar support, subjective sensibility evaluation was conducted and sitting body pressure was measured, and the change of lumbar spine angle was observed using X-ray image. Based on the results, design variables that affect the initial discomfort when sitting on a car seat and the correlation among these design variables were verified through statistical significance testing. The empirical analysis suggested that, among design variables of car seat lumbar support, the degree of prominence is the main variable that affects the initial discomfort when sitting for both Koreans and Americans, while the height and support width have very little to do with it. 相似文献
42.
We analyzed the lubrication characteristics of a design-selected spiral groove liquid seal for the critical component, the
carrier, of a rotary vane-type fuel pump developed for external installation on fuel tanks for liquid phase LPG (liquefied
petroleum gas) injection (LPLi) vehicles, with the aim of fundamentally improving lubrication performance and so protecting
the carrier from early frictional wear damage at its suction face. The main reason for selecting a spiral groove pattern was
because the viscosity of liquid LPG is very low, comparable to that of air, and current commercial dry gas seals adopting
spiral grooves have been successfully employed in completely noncontacting applications. Utilizing the Galerkin finite element
lubrication analysis method, a detailed lubrication characteristic analysis of the seal was performed, and lubrication performance
optimization was performed by systematic parameter analyses of the design variables. Compared to the initial reference design,
the final optimized spiral groove seal design had a groove depth increased by 66.7% and an equilibrium seal clearance increased
by 65.3%. Our model also predicted that under a condition of equilibrium between the closing force of the pumping pressure
and the seal opening force, the optimally designed carrier spiral groove liquid seal was capable of maintaining a stable lubricating
film with sufficient axial stiffness and thereby demonstrated successful noncontact operation; in addition, leakage through
the seal was minimal. 相似文献
43.
Two problems concerning the use of aerial photographs for conducting traffic studies in urban areas are considered in this paper: (1) Suitable procedures requiring simple equipment and methods and the appropriate formulae for determining the traffic characteristics of density, volume, traffic count, speed, composition; (2) Problems relating to flight planning for traffic surveys from the points of view of duration of photography and the scale of the photography from considerations of the reliability of the determined traffic characteristics, vehicle identification, and also economy. The conclusions concerning the flight planning were applied in a test flight from which traffic data were determined as illustrated in a sample calculation. 相似文献
44.
S. M. Yang S. H. Yoo D. S. Gi S. B. Choi K. S. Kim N. T. Jeong S. U. Choi M. W. Suh J. H. Lee 《International Journal of Automotive Technology》2016,17(4):671-679
While a screw is a fastening element that can tighten the two parts at low cost, the loosening of the screw is generated due to external forces such as repetitive load, vibration, and thermal stress. This phenomenon decreases the initial clamping force, and this can be a serious problem to the safety of the product. However, while fastening parts are handled through experiment and experience, there is a lack of research on the screw loosening of plastic fastening parts. For example, vehicles have various fastening parts. Among the fastening elements, screws are typically used for tightening parts of the vehicle door trim. Vehicle interior materials are mainly composed of plastic parts. Especially, the temperature of the vehicle interior changes from a sub-zero temperature to 100 degrees (°C) due to solar radiation. Unlike metals, plastic materials are commonly susceptible to the environment. In this study, the fastening screw of automotive door trim parts is selected. First, a screw loosening mechanism is implemented through Computer Aided Engineering (CAE) analysis and the influences of degradation are then analyzed. Secondly, the selecting method of clamping force is suggested through the analysis result of reduction according to the tightening torque. 相似文献
45.
U. B. Azimov K. S. Kim D. S. Jeong Y. G. Lee 《International Journal of Automotive Technology》2011,12(2):159-171
An experimental study has been performed on spray combustion and two-dimensional soot concentration in diesel (ULSD), GTL
and GTL-biodiesel fuel jets under high-pressure, high-temperature quiescent conditions. Instantaneous images of the fuel jets
were obtained with a high-speed camera. It was confirmed that by blending GTL with 20% rapeseed biodiesel, certain fuel properties
such as kinematic viscosity, density, surface tension, volatility, lower heating value and others may be designed and improved
to be more like those of conventional diesel fuel but with considerable decrease in the amount of sulfur, PAH, cold filter
plugging point, etc. The results showed that the spray tip penetration increased and the spray cone angle decreased when 20%
biodiesel fuel was added to GTL fuel. Autoignition of the GTL-biodiesel blend occurred slightly earlier than that of diesel
fuel. Experiments under high-pressure, high-temperature conditions showed that higher injection pressure induced a lower soot
formation rate. The integrated flame luminosity, which serves as an indicator of soot concentration in the fuel jet, was slightly
higher for the GTL-biodiesel blend than for pure GTL fuel due to the slightly higher sulfur content of pure biodiesel fuel. 相似文献
46.
The problem of wave scattering by undulating bed topography in a two-layer ocean is investigated on the basis of linear theory.
In a two-layer fluid with the upper layer having a free surface, there exist two modes of waves propagating at both the free
surface of the upper layer and the interface between the two layers. Due to a wave train of a particular mode incident on
an obstacle which is bottom-standing on the lower layer, reflected and transmitted waves of both modes are created by the
obstacle. For small undulations on the bottom of the lower layer, a perturbation method is employed to obtain first-order
reflection and transmission coefficients of both modes for incident wave trains of again both modes in terms of integrals
involving the bed-shape function. For sinusoidal undulations, numerical results are presented graphically to illustrate the
energy transfer between the waves of different modes by the undulating bed.
U. BASU was born in 1949. She is a professor in the Department Applied Mathematics, Calcutta University, India. Her current research
interests include water wave problems, continuum mechanics, etc. 相似文献
47.
考虑一种特殊类型的超图分解.证明了对任意的正整数v≥4和λ,存在具有[λv(v-1)(v-2)/18]个区组的MCλ(3,K4^(3)-e,v),其边超越中至多含有两条边. 相似文献
48.
新型快餐盒生物降解性能试验方法研究 总被引:1,自引:0,他引:1
通过固体培养微生物侵蚀试验、液体培养微生物侵蚀试验、降解过程中纤维素酶活性测定、纤维素酶侵蚀试验和降解过程中 C O2 生成体积分数的测定等试验结果分析,认为固体培养微生物侵蚀试验、纤维素酶侵蚀试验及 C O2 生成量测定试验可用于评价新型快餐盒生物降解性能。 相似文献
49.
变频技术是近年来应用范围广泛的一门技术,尤其在节约电能、自动控制等方面更为突出。变频技术应用在锅炉的燃烧控制中,既节约了电能,又使燃烧充分而节约了燃煤。由于改变了传统控制模式的运行方式,使锅炉自动燃烧控制系统运行更稳定,安全可靠。该系统应用于青岛四方机车车辆厂、山海关桥梁厂、齐齐哈尔车辆厂、南口机务段等单位,经测试效果明显,推广价值很大。 相似文献
50.