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51.
隔振降噪技术的实船应用 总被引:2,自引:0,他引:2
某型测量船主辅机采用的单层局部隔振、浮筏双层隔振及约束阻尼处理等隔振降噪技术,基内就其设计论证、实船应用和检测结果作一简介。 相似文献
52.
J. Benajes S. Molina R. Novella M. Riesco 《International Journal of Automotive Technology》2008,9(3):257-265
A combined theoretical and experimental study has been carried out to determine the real potential of reducing pollutant emissions
in a HD diesel engine by means of retarding the intake valve closing. The effects produced by this alteration of the basic
operation cycle have been examined by a preliminary modelling study, and from the obtained results, a modified camshaft was
manufactured with a delayed intake valve closing of 60 crank angle degrees. Single-cylinder engine tests were carried out
with this modified camshaft, and the emissions and fuel consumption were recorded. The results showed that the retarded intake
valve closing can enhance the premixed combustion phase, and thus simultaneously reduce soot and NOx emissions. Moreover,
the combustion process attained is extremely tolerant to exhaust gas recirculation, and by adoption of this measure, Euro-5
emissions limits can be achieved at the tested conditions without after-treatment. 相似文献
53.
J. R. Serrano F. J. Arnau V. Dolz A. Tiseira M. Lejeune N. Auffret 《International Journal of Automotive Technology》2008,9(3):277-288
This article presents a two-stage turbocharged heavy-duty diesel (HDD) engine designed to fulfil the US2007 anti-pollution
directive. This directive imposes very restrictive limits on the NOx and particle emissions of HDD engines. In this work,
the possibility of combining particle traps in the exhaust line to reduce soot emissions with very high EGR rates to reduce
NOx emissions is considered. This new generation engine implements two-stage turbocharging in order to improve the bsfc when
the engine is working on steady conditions as well as to optimize the engine transient response. After carrying out the tests,
the results were analyzed and the engine settings were adjusted to maximise its behaviour and minimise pollutant emissions.
NOx and soot emission peaks were also analyzed at engine transient conditions in order to keep them under certain levels,
and thus maintain the overall pollutant emissions to a level that is as low as possible. In summary, a double-stage turbocharging
configuration can greatly improve engine driveability (between 23% and 36% depending on engine speed), while reducing NOx
emissions during transient evolution without increasing opacity peaks beyond the stated limits. 相似文献
54.
针对TBD234V6型柴油机,采用AVL-fire软件对额定工况下,不同乙醇/水掺混比进行三维数值模拟研究,对比分析缸内压力、缸内温度、缸内温度场、燃烧放热率、NOx浓度、NOx浓度场、Soot浓度、Soot浓度场,并通过赋权法确定最优乙醇/水掺混比。结果表明:随着乙醇/水掺混比的增加,缸内压力逐渐升高,燃烧放热率滞后,燃油消耗率呈上升趋势,但在0E10W时,最高燃烧压力下降率约为3.7%;燃油消耗率下降0.38%;缸内高温分布区域缩小,NOx和Soot浓度下降。通过计算确定最优掺混比为20E10W,此时,最高燃烧压力提升5.6%,燃油消耗率上升2.41%,NOx排放下降率约为18.8%,Soot排放下降率约为29.6%。研究结果可为船用柴油机采用柴油/乙醇/水三燃料燃烧提供一定的指导依据。 相似文献
55.
详细介绍了双燃料发动机电力推进LNG船可燃气体探测系统设计的基本要求,包括可燃气体探头及取样管在不同区域的布置情况及数量要求。所述内容不仅涉及LNG船本身的要求,也覆盖了其他类型的液化气体运输船的相关要求。 相似文献
56.
H. Christopher Frey Kangwook Kim 《Transportation Research Part D: Transport and Environment》2009,14(8):585-592
In-use micro-scale fuel use and emission rates were measured for eight cement mixer trucks using a portable emission measurement system. Each vehicle was tested on petroleum diesel and B20 biodiesel. Average fuel use and emission rates increase monotonically versus engine manifold absolute pressure. A typical duty cycle includes loading at a cement plant, transit while loaded from the cement plant to work site, creeping in a queue of vehicles at the worksite, unloading, and transit without load from the site to the plant. For B20 versus petroleum diesel, there is no significant change in the rate of fuel use, CO2 emissions, and NO emissions, and significant decreases in emissions for CO, hydrocarbons, and particulate matter. For loaded versus unloaded onroad travel, fuel use and CO2 emissions rates are approximately 60% higher and the rates for other pollutants are approximately 30–50% higher. A substantial portion of cycle emissions occurred at the work site. Inter-vehicle and intra-cycle variability are also quantified using the micro-scale methodology. 相似文献
57.
陈平 《南通航运职业技术学院学报》2009,8(2):59-62
拉缸是柴油机常见的故障之一,直接影响柴油机的经济性、动力性和可靠性。文章介绍了船舶柴油机拉缸的主要征兆,分析了柴油机发生拉缸的原因,提出了针对柴油机拉缸所采取的相应措施。 相似文献
58.
机车柴油机喷油泵凸轮接触应力分析 总被引:2,自引:0,他引:2
针对机车柴油机喷油泵凸轮表面常出现点蚀、麻点、剥落等损伤问题,开展喷油泵凸轮轮廓升程段的接触应力研究,分析导致喷油泵凸轮表面失效的原因。以16V240ZJB型柴油机为例,通过对油泵凸轮轮廓曲线进行几何分析,导出凸轮升程段的运动方程。采用弹性力学中的赫兹理论,建立油泵凸轮接触应力的计算式,并通过计算机编程,从理论上计算和分析喷油泵凸轮表面的接触应力。理论计算结果表明:喷油泵凸轮的接触应力虽高达1 421.655 MPa,但并未超过许用应力值。因此建议从材料加工工艺方面查找原因,提高凸轮表面加工质量,并采用复合强化工艺,进一步加大喷油泵凸轮表面的强度。 相似文献
59.
建立了柴油机废气涡轮前的燃气能量和燃油消耗率的综合评价函数,采用多目标优化的方法,对PA6-280柴油机的进排气正时进行了优化计算,分析了配气正时的调控对柴油机性能的影响。 相似文献
60.
E. Zervas 《International Journal of Automotive Technology》2008,9(6):641-647
This work studies the impact of five parameters: CO and HC engine-out emissions, space velocity, average value and profile
of exhaust temperature, on Diesel CO and HC tail-pipe emissions. The first part of this work is conducted on a reactor and
shows that both HC and CO light-off temperature increases with CO and HC input concentration. CO and HC initial concentration
influence the adsorption/desorption capacities of HC only at high temperatures. Space velocity also influences CO and HC conversion
efficiency. The second part of this work studies the impact of different combinations of HC and CO engine-out emissions on
CO and HC conversion and tail-pipe emissions in the case of New European Driving Cycle. This part proposes that a Diesel oxidation
catalyst must be mainly studied at the Urban Part of NEDC, as the CO and HC conversions are very high at the extra-urban part
of NEDC. CO and HC conversion efficiencies are also dependent on exhaust temperature and catalytic volume. In the case of
two different profiles of exhaust temperature with the same average temperature, CO and HC conversion efficiency is lower
in the case of the smoother profile. 相似文献