锥形模镦锻极限的研究

本文分析了锥形模镦锻变形的三个阶段,提出了二次稳定镦锻的概念,给出了金属变形过程中几个瞬态的数学模型。在此基础上,提出了不产生空间螺旋弯曲的原始坯料长径比ψ_(nkp),并绘出了ψ_(nkp)-φ临界曲线,进而得出了为设计模具用的三条限制曲线。通过试验分析,提出了在长径比很大时镦锻模膛设计的限制曲线,并在生产中取得了满意的效果。     

删除卷积码与MPSK调制

格型编码调制ＴＣＭ把卷积编码和ＰＳＫ或ＱＡＭ调制相结合，在功率有限和带宽有限的信道中能够获得较大的编码增益，中提出了一种将删除型卷积码和ＭＰＳＫ调制结合的方法，使译码的复杂度降低，并在计算机上对具有最大欧几里德距离，信息率ｒ为２／３的删除只编码调制的好码进行了搜索。     

一种计算TCM码的欧几里德距离和乘积距离的方法

提出了计算非规则篱笆图的最小欧几里德距离和最小乘积距离的一种有效算法，该算法是在Ｖｉｔｅｒｂｉ算法的基础上，对起始于任意状态和终止于任意状态所有参考路径上的距离进行了计算，求得最小欧几里德距离和最小乘积距离，它适用于搜索斯信道和衰落信道中的ＴＣＭ好码。     

分析湍流间歇性的双流体模型

本文阐述湍流的双流体模型,并用于计算湍流自由射流的间歇性.还研究了两种流体间的质量交换和摩擦作用对间歇性的影响.计算结果令人鼓舞.     

近年来关于应力腐蚀(SCC)的研究

应力腐蚀开裂(SCC)是金属材料的腐蚀问题中的重要部分。它指金属在特定介质中由于受稳定应力产生尖锐的裂纹而造成的金属材料的腐蚀破坏。它比较复杂,受许多因素的影响。因而对SCC的研究需要各方面的工作(图1)。 自1906年开始出现关于SCC的文章后的近80年中,人们从冶金学,断裂力学、物理和化学等各方面创造了一系列研究方法,从不同角度分析和总结,并提出了许多有关机理。对六、七十年代此方面的工作已有许多人进行过归纳和总结。这里在简单回顾以往工作的基础上主要归纳近两年来的有关工作。     

基于SMPP协议的USSD应用会话流程的实现

主要介绍了GSM通信中的SMPP(shortm essage peer to peer)应用协议,以及它的一个主要应用业务USSD.并根据SMPP协议以及华为的USSD(unstructured supp lem entary service data)业务协议对USSD应用程序的会话流程进行了设计实现.     

Construction and anti-tumor effects of recombinant fowlpox virus expressing Newcastle disease virus hemagglutinin-neuramidinase gene

Hemagglutinin-neuramidinase (HN), a Newcastle disease virus-derived protein, not only mediates receptor recognition but also possesses neuraminidase (NA) activity, the ability to cleave a component of those receptors, N-acetylneuraminic acid (NAcneu, sialic acid). It is known that this protein in mammalian species, including human beings, has interesting anti-neoplastic as well as immune stimulating properties. To explore the use of the HN gene in cancer gene therapy, we constructed a recombi-nant fowlpox virus expressing the HN protein (vFV-HN) and compared the anti-tumor activity of the recombinant virus with that of wild-type fowlpox virus (FPV) in vivo and in vitro. Here we found that although B16 cells were somewhat resistant to the basal cytotoxic effect of wild-type fowlpox virus, infection with vFV-HN caused a pronounced cytotoxic effect and, the survival of tumor-bearing mice immunized with vFV-HN was significantly increased compared with the survival of mice immunized with the FPV alone. Furthermore, the immunization of mice with vFV-HN elicited a B16 tumor-specific cytotoxic T lymphocyte (CTL) response and clonal expansion of both CD4 and CD8 T cell populations in vivo. In addition, T cells from lymph nodes of mice vaccinated with vFV-HN secreted high levels of the Th1 cytokine IL-2 and IFN-γ, indicating that the regression of tumor cells is related to a Th1-type dominant immune response. These results demonstrate that vaccination with vFV-HN may be a potential strategy for cancer gene therapy.     

A new frequency scale of Chinese whispered speech in the application of speaker identification

In this paper, the frequency characteristics of Chinese whispered speech were investigated by a filter bank analysis. It was shown that the first and the third formants were more important than the other formants in the speaker identification of Chinese whispered speech. The experiment showed that the 800?1200 Hz and 2800?3200 Hz ranges were the most significant frequency ranges in discriminating the speaker. Based on this result, a new feature scale named whisper sensitive scale (WSS) was proposed to replace the common scale, Mel scale, and to extract the cepstral coefficient from whispered speech signal. Furthermore, a speaker identification system in whispered speech was presented based on the modified Hidden Markov Models integrating advantages of WSCC (the whisper sensitive cepstral coefficient) and LPCC. And the new system performed better in solving the problem of speaker identification of Chinese whispered speech than the traditional method.     

一次天津地区暴雨过程的中小尺度分析

用NCEP再分析资料、雷达资料以及地面自动站每小时资料对2005年6月28-29日发生在天津地区的局地暴雨天气进行诊断分析,研究结果表明:高低空急流耦合是暴雨发生发展的有利背景,由天津市西南方向移来的中尺度系统与市区地面中尺度辐合线共同作用是产生这次局地暴雨天气的直接触发机制。天津市区的局地条件在这次局地降水的过程中起到了相当重要的作用。     

国家农业科技园区技术对接机制的运行模式

技术对接功能是农业科技园区的核心功能之一,国家农业科技园区技术对接机制的运行模式是技术对接效果的决定因素。对国家农业科技园区技术对接机制的涵义及运行模式进行分析,归纳了四种国家农业科技园区技术对接机制运行的模式。