Effect of Connecting the Front and Rear Air Suspensions of a Vehicle on the Transmissibility of Road Undulation Inputs

Airsprings have been used for vehicle suspensions over the last 40 years. They are mostly used as independent suspensions. Analysis of air springs available in literature is mostly limited to a single-degree-of-freedom system or a two-degrees-of-freedom system only in the translation mode. This paper deals with a model of a vehicle where the front and the rear springs are connected by a capillary tube. A two-degrees-of-freedom model having motion in bounce and pitch mode is presented. Equations of mass flow are linearized on the assumption of small variations in volume and pressure. Expressions for the transmissibility and the phase angle in the bounce and the pitch mode are derived. Road inputs to the front and the rear axles are assumed to be identical except for a phase difference between them. The effect of the capillary flow coefficient and that of the phase angle between the front and the rear axle excitation are studied. It is shown that an optimum value of the capillary flow coefficient exists which minimizes the transmissibility of motion in both modes over the entire frequency range. It is also observed that a phase angle of 180 degrees presents ideal transmissibility characteristics. Thus, a promising application of air springs for a vehicle suspension is presented.     

出口苏丹米轨平车研制

介绍了出口苏丹米轨平车的技术参数、结构特点和试制情况。     

低噪声车轮的原理、试验及应用前景

通过理论分析和试验，对欧洲近几年的几种低噪声车轮的设计原理及试验效果做出了评价，对低噪声车轮在货运及高速运输中的应用前景做了分析。     

The influence of food quality on the nutritional acclimation of the copepod Acartia clausi

The influence of food quality on the nutritional metabolism of Acartia clausi was studied experimentally using four different diets: (1) diatom cells of Thalassiosira weissflogii, (2) detritus prepared from the same culture, (3) 50 : 50 mix on a protein basis of the two previous diets, and 4) dinoflagellate cells of Prorocentrum micans. For each trophic, ingestion, gut transit time, trypsin activity and K_m (half saturation constant) were measured at limiting and saturating concentration. Assimilation rates were also estimated for both pure diatoms and mixed live–detrital cell diets. Ingestion followed a Holling type 2 response for diets 1 and 4, a linear one for detritus and an intermediate response for diet 3. Gut transit time displayed different adaptive changes with food regime depending on protein concentration. Trypsin activity was lower for detrital food and trypsin K_m significantly decreased with increasing concentration of live diatoms. Assimilation rates were higher for live food than for mixed live–detrital food. Results illustrated that Acartia-type copepods optimize nitrogen or protein uptake. They suggest that besides chemoreception-mediated selectivity, internal controls by digestion and assimilation also regulate ingestion (feed-back).     

CRD与双侧壁工法在铁路客运专线湿陷性黄土大断面隧道施工中的应用

介绍郑西铁路客运专线台村及盘东两座黄土隧道采用CRD法和双侧壁法施工的情况,并对该两种施工工况下监控量测结果及变形特征进行总结分析。     

含增生结节鼠肝谷胱甘肽转硫酶的纯化和性质研究

含增生结节鼠肝GST活性在纯化过程各步均较正常肝明显增高,经DEAE-52和CM-52柱层析分离得阴离子同工酶A-1和A-2以及阳离子同工酶C-1,C-2,C-3和C-4,用等电聚焦电泳测定等电点分别为6.7,6.3,7.4,7.9,8.3和8.6。SDS-PAGE结果显示,含增生结节肝GST在正常大鼠肝GSTYa,Yb和Yc区带相应的位置,出现3条区带,各亚基分子量分别为26,000,27,000和28,600道尔顿,但活性增高明显的C-3和C-4只出现1条相当于Yc亚基的区带。含增生结节肝GST6种同工酶的带电性质及亚基组成与正常肝无明显差别。阳离子同工酶C-3和C-4活性占上柱总活性的70%,说明含增生结节肝GST活性增高以阳离子同工酶为主。     

国际互联网上信息安全法律问题的现状和发展

系统阐述了依法管理和改进国际互联网网络安全技术是世界各国在国际互联网上的普遍做法。为了禁止网络犯罪，保证网络安全运行，许多国家都十分注意依法管理。需颁布《伪造访问设备和计算机欺骗与滥用法》、《中国通信隐私法》、《计算机欺骗和滥用法》、《计算机滥用法案》等法律法规。     

遂渝铁路二线复杂隧道工程地质勘察分析研究

遂渝二线经合川后线路主要以3座隧道通过，隧址区地形地质复杂，不良地质与特殊岩土发育，采用物探、钻探、原位测试及取样试验等综合勘察手段，通过资料相互补充、相互验证，较好地查明了隧址区各种不良地质与特殊岩土分布范围及特征，分析了可能发生的地质灾害，提出了处理措施的建议。