汉语习惯表达在汉英中介语中的负迁移

已有的母语知识结构在二语习得过程中起阻碍或干扰作用,就会发生语言的负迁移。因此,中国人学习英语时,受到汉语表达习惯的影响,常常会造出具有中国特色的英语句子,即Chinglish。这既是汉语习惯表达在英语学习中负迁移的结果。     

Research on heat dissipation characteristics of magnetic fluid bearings under multiple field coupling effects

This paper analyzes the sources of heat losses in magnetic fluid bearings,proposes various cou-pling relationships of physical fields,divides the coupled heat transfer surfaces while ensuring the continuity of heat flux density,and analyzes the overall heat dissipation pathways of the bearings.By changing parameters such as input current,rotor speed,and inlet oil flow rate,the study applies a multi-physics field coupling method to investigate the influence of different parameters on the temper-ature field and heat dissipation patterns of the bearings,which is then validated through experi-ments.This research provides a theoretical basis for the optimal design of magnetic fluid bearing sys-tems.     

Analysis of rotor eddy current loss and thermal deformation of magnetic liquid double suspension bearing

Magnetic-liquid double suspension bearing(MLDSB)is a new type of suspension bearing based on electromagnetic suspension and supplemented by hydrostatic supporting.Without affecting the electromagnetic suspension force,the hydrostatic supporting effect is increased,and the real-time coupling of magnetic and liquid supporting can be realized.However,due to the high rotation speed,the rotor part produces eddy current loss,resulting in a large temperature rise and large ther-mal deformation,which makes the oil film thickness deviate from the initial design.The support and bearing characteristics are seriously affected.Therefore,this paper intends to explore the internal effects of eddy current loss of the rotor on the temperature rise and thermal deformation of MLDSB.Firstly,the 2D magnetic flow coupling mathematical model of MLDSB is established,and the eddy current loss distribution characteristics of the rotor are numerically simulated by Maxwell software.Secondly,the internal influence of mapping relationship of structural operating parameters such as input current,coil turns and rotor speed on rotor eddy current loss is revealed,and the changing trend of rotor eddy current loss under different design parameters is explored.Thirdly,the eddy cur-rent loss is loaded into the heat transfer finite element calculation model as a heat source,and the temperature rise of the rotor and its thermal deformation are simulated and analyzed,and the influ-ence of eddy current loss on rotor temperature rise and thermal deformation is revealed.Finally,the pressure-flow curve and the distribution law of the internal flow field are tested by the particle image velocimetry(PIV)system.The results show that eddy current loss increases linearly with the in-crease of coil current,coil turns and rotor speed.The effect of rotational speed on eddy current loss is much higher than that of coil current and coil turns.The maximum temperature rise,minimum temperature rise and maximum thermal deformation of the rotor increase with the increase of eddy current loss.The test results of flow-pressure and internal trace curves are basically consistent with the theoretical simulation,which effectively verifies the correctness of the theoretical simulation.The research results can provide theoretical basis for the design and safe and stable operation of magnetic fluid double suspension bearings.     

巴基斯坦天然气水合物潜力:满足未来能源需求的可能解决方案

提供了一个可以利用卫星成像技术证明水合物的存在和评估巴基斯坦境内天然气水合物饱和度的可行性模型.研究证明了巴基斯坦具有开采天然气水合物的极大潜力.阿拉伯海的卫星图像与海底模拟反射器(BSR)的联合作用,可以预测其中是否存在水合物和潜在能源.此外,热成像技术成本较低,结合它的创新性,都极大地增加了水合物探测的性价比,其中...     

孟加拉湾4个典型地区的涡旋热和盐输送

利用涡扩散法、海面高度资料和气候水文资料,对孟加拉湾海域海盆尺度涡(湍流)致热盐输运进行了估算.结果发现,在孟加拉湾大量的涡致输运主要存在于4个区域:孟加拉湾北部的西部边界(NB)、孟加拉湾西部(WB)、斯里兰卡南部和东部(SWB)以及孟加拉湾东南部靠近马六甲海峡区域(SEB).根据涡输运的气候态分布,涡致热输运主要存...     

相转移条件下钯催化芳基卤化物的Heck羰基化反应

在聚乙二醇（ＰＥＧ）、碱及催化量的钯催化剂存在下,芳基卤化物和一氧化碳可在常压下进行羰基化反应,高产率地生成相应的芳香羧酸。     

帧中继技术与数据通信

就帧中继的产生与特点作了简要的介绍,阐述了随着局域网互连的发展,采用帧中继技术取代Ｘ．２５和ＤＤＮ（数字数据网）通信方式,不仅能满足速率高、动态分配带宽、组网方便、费用低廉的需要,而且从帧中继主干网向ＡＴＭ（异步转移模式）主干网平稳过渡是非常方便和经济的,帧中继也将成为ＡＴＭ主干网的主要用户接入方式。     

ATM网络中恒定比特率和可变比特率语音通信

分析了ＡＴＭ（异步转移模式）网络中恒定比特率（ＣＢＲ）和可变比特率（ＶＢＲ）语音通信方式,讨论了ＩＴＵＴ１９９７年新颁布的ＡＴＭ可变比特率业务适配标准ＡＡＬ２,给出了信元装配实例。针对ＶＢＲ业务相对ＣＢＲ业务有较大不同的网络传输时延特性,着重分析了语音信号作为ＶＢＲ业务采用ＡＡＬ２适配标准时,通过ＡＴＭ网络传输时的装配时延问题。     

抗冻肽基因在热激表达盒式载体中的构建

克隆于细菌表达载体ｐ＾ＧＥＭ－３ｘｆ（－）中的ＡＦＰ基因经ＳａｌＩ和ＫｐｎＩＩ消化后,插入到热激盒式表达载体ｐ＾ＭＡ４１２的ＳａｌＩ和ＫｐｎＩ位点中,连接于可融合的报道基因元。     

热滞蛋白界面吸收反应的动力学描述

通过热滞蛋白在冰晶表面吸附反应的动力学过程,给出了热滞蛋白活性与其溶液浓度的关系．理论结果与实验数据较好地符合．