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341.
Y. S. Pyoun H. T. Kim Y. C. Lee A. Gafurov H. Kim D. H. Jung 《International Journal of Automotive Technology》2008,9(1):61-70
Surface topology, cone angle and the forces acting on the cone of the clutch type limited slip differential (LSD) are major
design parameters for the bias ratio and the noise condition. Therefore much research has been dedicated to these developments
but the results have been used to submit patents. A new cone type limited slip differential for sport utility vehicles and
recreational vehicles, which has a very simple structure and easy compliance with the vehicle performance, has been developed
by the axiomatic approach and the ultrasonic nano crystal surface modification (UNSM) technology. The design criteria and
optimal value of the design parameters are determined by the axiomatic approach utilizing CAE tools. Test methodologies in
a test rig and in a vehicle were also developed. Test results showed good performance of bias ratio and noise level but durability
is still under testing. This study is an extension of F2006P266, FISITA 2006. 相似文献
342.
H. N. Kim T. J. Kim B. C. Choi M. T. Lim 《International Journal of Automotive Technology》2008,9(5):563-570
The objective of this experimental study is to investigate the characteristics of the size distribution and the number concentration
of PM (particulate matters) emitted from the diffusion flame of a boiler burner, which has the same type of combustion as
a diesel engine. This study is performed to investigate the emission characteristics of nanoparticles generated from diffusion
combustion in diesel fuel, and it considered fuel factors and the reaction characteristics of the nanoparticles on the DOC
(Diesel oxidation catalyst). The factors examined in this experiment included the sulfur content in the fuel, the blend of
the diesel fuel containing biodiesel and bio-ethanol, and the concentration of engine oil (0.1% and 1.0%) blended with diesel
fuel. The particle size distribution of the nanoparticles exhausted from the boiler burner was measured by an SMPS (scanning
mobility particle sizer). The number concentration of PM that were smaller than 70 nm in diameter greatly increased in the
rear of the DOC when fuel containing 250 ppm of sulfur was used. The experiment also suggested that the particle number concentration
in both the front and rear of the DOC was lower when ULSD (ultra low sulfur diesel) fuel blended with biodiesel and bio-ethanol,
which are oxygenated fuels, was used than when only ULSD fuel was used. The higher the content of engine oil in the fuel,
the higher the particle number concentration was in the front and rear of the catalyst. When the first dilution air temperature
is increased from 30°C to 180°C, the nanoparticle number concentration dramatically dropped in the rear of the catalyst when
fuel containing 250 ppm of sulfur was used, while the particle size distribution remained almost the same when the fuel with
engine oil was used. 相似文献
343.
Dong Won Yi Soung Hie Kim Hyung Rim Choi Nam-Kyu Park Tae-Woo Lee 《Maritime Policy and Management》2000,27(2):155-167
It is an important matter closely connected with saving logistics costs, as well as encouraging national competitive power, to improve the productivity of container terminals by efficient utilization of container terminal resources. In this respect, this paper tries to suggest a conceptual model for sharing container terminal resources, taking as a case study the Gamman Container Terminal (GCT) in the port of Pusan. In so doing, it identifies what kinds of resources can be systematically shared from the viewpoint of their common use and draws some problems resulting from terminal operation by four operators at GCT. The model does not imply the conception that each terminal has its own resources individually, but recommends that tentatively-called Container Terminal Resource Management Center (CTRMC) should be established and operated in order to save operation and investment costs and improve operational efficiency. In addition, the continuous acquisition and life-cycle support (CALS) concept is imbedded in the model so that it can control the supply and demand of resources efficiently by sharing the database, through which the CTRMC can automatically identify the status of the excess or deficit of a certain resource in each berth at GCT. 相似文献
344.
K. -S. Choi S. -H. Jang G. S. Shin H. -M. Kim H. C. Yoon M. E. Forrest P. A. Erickson 《International Journal of Automotive Technology》2010,11(3):429-434
The commercial fuel cell products currently appearing on the market are self-contained fuel cell engines. These engines can
be used for many applications that are presently dominated by internal combustion engines or batteries. Vehicle mounted fuel
cell auxiliary power units have been attracting attention lately. Additionally, there is a market based incentive to use multiple
small fuel cell arrays in place of a single large fuel cell for some applications. Typically, fuel cells are designed to operate
as stand-alone units. This paper investigates the ability of small commercial stacks to operate in common array arrangements.
Although an individual Nexa is able to produce 1500 W, Dual Nexas do not maintain that capability while in array configurations.
With an overall load share ratio of 1.02:1 the series array reliably produced 2900 W of power, while with an overall load
share ratio of 1.09:1 the parallel array reliably produced only 2800 W of power. This study shows that array orientation affects
both system stack net efficiency and individual stack net efficiency. The information gained from this study may be helpful
for fuel cell design and integration. 相似文献
345.
Hydroplaning tires have been frequently simulated using commercial explicit FEM (Finite Element Method) codes. However, these
simulations are slow, and the result of the lift force is so oscillatory that the hydroplaning speed cannot be accurately
determined. Thus, in the author’s previous study, a new methodology using FDM (Finite Difference Method) code and an FE tire
model iteratively was proposed. However, this full iteration method still required a long computation time, especially for
patterned tires. Thus, in this study, the full iteration methodology was modified such that no iteration or only one additional
iteration was needed at each speed. Then, by applying the full iteration method, no iteration method and one iteration method,
the hydroplaning speeds of a straight-grooved tire were determined, and it was noted that the hydroplaning speed obtained
from the one iteration method was almost the same as that obtained from the full iteration method. Moreover, the hydroplaning
speeds of two patterned tires were determined using the one iteration method, and they were compared with the hydroplaning
speeds obtained experimentally. 相似文献
346.
D. Kim Y. H. Kim S. Gururaja M. Ramulu 《International Journal of Automotive Technology》2010,11(6):849-855
The random direction short Glass Fiber Reinforced Plastics (GFRP) have been prepared by two compression moulding processes,
namely the Preform and Sheet Moulding Compound (SMC) processes. Cutting force analysis and surface characterization are conducted
on the random direction short GFRPs with varying fiber contents (25∼40%). Edge trimming experiments are preformed using carbide
inserts with varing the depth of cut and cutting speed. Machining characteristics of the Preform and SMC processed random
direction short GFRPs are evaluated in terms of cutting forces, surface quality, and tool wear. It is found that composite
primary processing and fiber contents are major contributing factors influencing the cutting force magnitudes and surface
textures. The SMC composites show better surface finish over the Preform composites due to less delamination and fiber pullouts.
Moreover, matrix damage and fiber protrusions at the machined edge are reduced by increasing fiber content in the random direction
short GFRP composites. 相似文献
347.
S. -J. Park S. -W. Chae E. -S. Kim 《International Journal of Automotive Technology》2010,11(3):441-445
Neck fracture is a major cause of death in traffic accidents. This pattern of injury normally occurs in a frontal collision
or overturn of a vehicle. This study investigates the case of a neck fracture from a low-speed collision. In the examined
case, the passenger in the front seat of the car fractured his neck and died. He did not have his seatbelt on when the vehicle
slipped on a frozen road surface on a downward slope of a hill and impacted into the shoulder of the road at low speed. In
this type of collision, an occupant’s body will be impacted by the windshield or other interior trim of the car. However,
in this case, rather unusually, neither body tissue nor fiber remained although the collision involved a broken windshield.
Thus, the reason for the passenger death was unidentified. This study applied the computer simulation package Madymo for analyzing
the accident. The result of the simulation was that the passenger, who did not wear a seatbelt, moved forward due to inertia.
The upper part of the passenger then rotated and lifted when the knee contacted with the dashboard. By evaluating the structural
deformation of the vehicle at the front, we deduced that the collision velocity was 30 km/h. Through a computational experiment
that was undertaken using Madymo 7.0, NIC was estimated to be 240 m2/s2. This result far exceeded the threshold for neck injuries. In particular, in comparison with whiplash injuries, when the
passenger’s head directly impacts the roof following a rear-end collision, the bending moment through hyperextension of the
neck is greatly increased. In this study, we concluded that the manner of death was the hyperextension of the neck, as the
passenger’s head contacted the roof from underneath. 相似文献
348.
S. H. Jeong C. G. Choi J. N. Oh P. J. Yoon B. S. Kim M. Kim K. H. Lee 《International Journal of Automotive Technology》2010,11(3):409-416
This paper presents a low cost design and implementation of a parallel parking assist system (PPAS) based on ultrasonic sensors.
Generally, a PPAS requires several types of sensors, such as an ultrasonic sensor, camera sensor, radar sensor and laser sensor
for parking space detection. However, our proposed PPAS only requires two ultrasonic sensors on the front and lateral sides
for parking space detection. Moreover, a steering angle sensor and wheel speed sensor installed in the vehicle are used to
obtain vehicle position information for localization in ultrasonic range data. The hardware architecture of the PPAS based
on an electronic control unit (ECU) module, sensor modules and a human machine interface (HMI) module was proposed. Moreover,
the software architecture of the PPAS is based on system initialization, scheduling, recognition and a control algorithm.
In particular, a novel sensor algorithm was proposed to minimize the vehicle corner error of the ultrasonic sensor. A prototype
of the PPAS based on the proposed architecture was constructed. The experimental results demonstrate that the implemented
prototype is robust and successfully performs parking space detection and automatic steering control. Finally, the low cost
design and implementation of the PPAS was possible due to the cheap ultrasonic sensors, simple hardware design and low computational
complexity of the proposed algorithm. 相似文献
349.
Y. -M. Kim Y. -G. Kim S. -W. Kim C. -K. Park T. -W. Park 《International Journal of Automotive Technology》2010,11(5):673-680
The performance of brakes has become important due to increased train speeds. The brake system of a train must possess a large
brake force to stop the train safely within a limited stopping distance. However, an excessive brake force deteriorates the
ride comfort and causes the train to skid. Therefore, it is necessary to control the brake force within the adhesion force
limit. This paper presents an analytical method to estimate the relationship between the brake and adhesion forces of a disc
brake system. This method has been applied to the actual disc braking control system of the Korea High-Speed Train (HSR350x),
and the adhesion force is estimated in an actual skid condition. 相似文献
350.
Using the recent anthropometry of the North American population, human body models were developed for seat comfort simulation.
The external geometry of the models was acquired from the three-dimensional whole body laser scan of recruited volunteers
in a driving position. The selection criteria for volunteers with standard size and shape were derived from a statistical
factor analysis of the Size USA database. As a practical application of the model in a design process, comfortable driving
postures were constructed by adopting the cascade prediction model (CPM), which takes into account both interior package layout
and the driver’s anthropometry. The detail modeling process of finite element modeling and its validation results against
volunteer measurements are introduced. 相似文献