CA6102型车用汽油机燃烧室的改进

在单缸试验机上对ＣＡ６１０２型汽油机燃烧室的改进试验结果表明：该燃烧室在燃用ＭＯＮ７０汽油时具有较强的抗爆能力和较高的燃烧速率，利于采用较高压缩比和燃用稀薄混合气，改善了发动机的燃油经济性和动力性，且生产时无须更改原有加工设备，便于推广应用．     

人αB干扰素基因在PGK1启动子和α因子前导序列控制下在酵母中的表达和分泌

借助化学合成的寡聚核苷酸接头将酵母PGK1启动子和α因子前导序列相连构建成一个αB干扰素基因的分泌表达载体YFD65.含质粒YFD65的酵母菌BJ1991能分泌表达αB干扰素,分泌到培养基中的αB干扰素的量为10~8U/L.     

流体入口温度对换热器热力学性能影响的分析

采用Ｙｏｎｇ分析方法,分析了高低温换热器的热力学特性,给出了高低温温换热器Ｙｏｎｇ效率的计算式在考虑了和不考虑压力Ｙｏｎｇ损失这两种情况下,系统地讨论了冷热流体入口温度高代温换热器Ｙｏｎｇ效率的影响。     

金黄色葡萄球菌VBNC 状态的诱导条件和EMA-qPCR 检测

为建立金黄色葡萄球菌(Staphyloccocus aureus) 活的非可培养( VBNC) 状态的诱导条件模型,考察了温度、盐度和酸度3 个因素对金黄色葡萄球菌细菌可培养数的影响,通过正交试验优化得到了VBNC 状态的诱导条件,同时观察细菌可培养数的变化,建立了DNA 结合染料叠氮溴乙锭(EMA) 与qPCR 技术相结合检测VBNC 金黄色葡萄球菌的方法. 实验结果表明:细菌可培养数受酸度的影响最大,VBNC 状态的最佳诱导条件为菌液在含15%NaCl 和0. 3%乙酸的营养肉汤培养基中于4 ℃下培养12 d;通过正交试验诱导后的不可培养菌可由EMA-qPCR 方法有效检出,其与qPCR 法的Ct 值( 荧光信号达到设定的阈值所经历的循环数)之差在1. 29 ~8. 56 之间变化.     

Model tests on anomalous low friction and pendulum-type wave phenomena

The anomalous low friction (ALF) and pendulum-type wave (μwave) phenomena were two typical,nonlinear,geo-mechanical,and dynamic responses in deep-block rock mass discovered from in situ observations,which occurred from the movement of the geo-blocks under the impact of external pulses,such as deep confined explosion,earthquake,and rock bursts.With the aim to confirm the existence of the above two phenomena and study the variation laws of them experimentally,laboratory tests on the granite and cement mortar continuum and blocks models were conducted on the self-independently developed multipurpose testing system,respectively.The ALF phenomenon was realized under two loading schemes,the blocks model and working block were acted upon by the joint action of vertical impact and horizontal static force as well as the joint action of both vertical and horizontal impacts with different time intervals.It revealed that the discrete time delays corresponding to the local maximums and minimums of the horizontal displacement amplitudes and residual horizontal displacements of the working block satisfied the canonical sequences with the multiple of √2,most of which satisfied the quantitative expression (√2)~i △/V_p.Besides,the one-dimensional impact experiments were carried out on the blocks granite model,continuum,and blocks cement mortar models,respectively.Based on the comparison and analysis of the propagation properties (amplitudes and the Fourier spectrums of acceleration time histories of blocks) of the 1D stress wave in the above models,it is indicated that the fractures in rock mass have tremendous effect on the attenuation of acceleration amplitudes and high-frequency waves.By comparison of the model test data with the in situ measurement conclusions,the existence of the μ wave was confirmed experimentally in the cement mortar blocks model with larger dimensions,and the frequencies corresponding to the local maximums of spectral density curves of three-directional acceleration time histories of sub-blocks also satisfied several canonical sequences with the multiple of √2.     

Web Information Retrieval的分析与展望

网络的飞速发展使得网络信息检索成为人们迫切的需求。本文对网络信息检索技术进行了介绍、分析和比较,在此基础上,对未来的应用前景进行了展望。     

变系数的强反射分离技术及应用

基于地震多子波分解的强反射识别与分离技术已广泛应用于地震解释性处理环节中,该技术能够去除强屏蔽影响,提高隐蔽储层的识别精度.针对多子波分解技术在分解效率和分解精度上的问题,引入地震信号的瞬时特性作为初始值,根据小波参数之间的关系减少局部扫描参数,提出了一种三参数快速子波分解技术提高了子波分解精度和效率.通过模型正演分析了地层厚度与强屏蔽能量的关系,建立了地层厚度与分离系数的关系,探索了一种变系数的强反射分离应用思路.将新技术和新思路应用于实际地震数据,分离结果削弱了强屏蔽的影响,突出了隐蔽储层的有效信号,提高了储层预测精度;由于强反射分离过程充分考虑了不同厚度的煤层与分离系数的关系,分离结果更加符合实际地质情况.     

泰北华人村华语状态及教育情况调查报告

泰北华人村是一个极为特殊而尴尬的华人聚集区,本文利用国家侨办组织赴泰北进行汉语教师培训的机会,对该地华语使用情况和华文教育情况进行了一些初步的调查和分析。由于外界因素的影响,该地华语的使用情况已经发生了许多变化;由于条件的限制,该地的华文教育还相当落后。希望本文能引起各界人士和专家对该群体的更多关注。     

矩阵正态分布的一个应用

李泽慧、乔彦友在[1]中提出了对于正态分布x=(x_1…x_n)′～N(u,Σ),X与S_n~2何时相互独立的问题,本文将此问题推广到矩阵正态分布的一般情况,并通过矩阵正态分布的性质,完全解决了此问题。     

Cloning and expression pro?les of 15 genes encoding WRKY transcription factor in wheat (Triticum aestivem L.)

WRKY proteins are involved in various physiological processes, including biotic and abiotic stress responses, hormone responses and development. However, no systematic identi?cation, expression and function analysis of WRKY genes in wheat were reported. In this study, we isolated 15 wheat cDNAs with complete open reading frame (ORF) encoding putative WRKY proteins using in silico cloning.Phylogenetic analysis indicated that the 15 wheat WRKY genes belonged to three major WRKY groups. Expression analysis revealed that most genes expressed drastically in leaf, except TaWRKY10 which expressed in crown intensively. Four genes were strongly up-regulated with the senescence of leaves. Eight genes were responsive to low temperature, high temperature, NaCl or PEG treatment. Moreover,differential expression patterns were also observed between wheat hybrid and its parents, and some genes were more responsive to PEG treatment in the hybrid. These results demonstrated that wheat WRKY genes are involved in leaf senescing and abiotic stresses. And the changed expression of these WRKY genes in hybrid might contribute to the heterosis by improving the stress tolerance in hybrids. 2007 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved.