二次边界载荷下脆性材料动态拉伸承载能力

结合有限结构-时间准则,得到了二次边界载荷下脆性材料动态拉伸承载能力的解析表达式. 分析说明:脆性材料的动态拉伸承载能力可以由外载荷的特征和材料的准静态材料参数相互作用完全决定,因此脆性材料动态强度的应变率效应并不是材料的内禀性质. 此外,不同的外部载荷所导致的材料动态拉伸承载能力有所不同,这是以前动态实验数据中具有内在离散特性的原因.      

梯度神经网络在p次方根求解中的应用

设计了一个针对一般问题求解的梯度神经网络模型.为了求解p次方根,定义一个基于平方的标量取值的能量函数,再根据梯度下降法,进一步推导出求解p次方根的梯度神经网络模型.使用Matlab仿真软件进行建模、仿真和验证,计算机仿真结果证实了梯度神经网络实时求解p次方根的有效性.     

卫星定位导航原理的实验课程设计与实践

针对卫星导航定位技术的教学要求,提出了一套完整的卫星导航定位技术实验课程建设方案。该方案分别从理论和工程实践的角度出发,并考虑学生对Matlab等编程工具的使用能力,设计了七个实验课程。通过教学实践证明,该实验方案取得了良好的教学效果,同时,从教学实践情况和学生反馈信息也验证了该实验课程方案的可行性和创新性。该方案是一种由以教为主向以学为主教学模式转变的新尝试,将工程背景和科学研究相结合,为电子信息工程专业课程体系建设提供了依据。     

广州大学物理实验教学模式改革的研究与实践

总结了广州大学物理实验教学模式改革的思路及方案,实验教学体系建设,实验教学方法和手段,教学过程、内容和考核方式等实践过程中的经验和体会.阐述了实验课程定位与建设理念,探讨了实验教学方法的创新,介绍了教学改革所取得成果.     

带有破产风险的可转换债券的定价模型及其解法

把可转换债券看作股票和利率的衍生资产，利用Vasicek模型和COX模型得到了可转换债券的定价模型．虽然不能得到这个模型的显式解，但利用相关理论得到了这个解存在的一个充分条件．     

物理学教学中的类比方法类型及应用

通过实践教学和理论研究,提出了物理教学中类比方法的几种类型及其具体应用,同时介绍了类比方法在教学中的作用及其在应用中应注意的问题.     

The DNA sequence of human chromosome 22

Knowledge of the complete genomic DNA sequence of an organism allows a systematic approach to defining its genetic components. The genomic sequence provides access to the complete structures of all genes, including those without known function, their control elements, and, by inference, the proteins they encode, as well as all other biologically important sequences. Furthermore, the sequence is a rich and permanent source of information for the design of further biological studies of the organism and for the study of evolution through cross-species sequence comparison. The power of this approach has been amply demonstrated by the determination of the sequences of a number of microbial and model organisms. The next step is to obtain the complete sequence of the entire human genome. Here we report the sequence of the euchromatic part of human chromosome 22. The sequence obtained consists of 12 contiguous segments spanning 33.4 megabases, contains at least 545 genes and 134 pseudogenes, and provides the first view of the complex chromosomal landscapes that will be found in the rest of the genome.     

Compact sources as the origin of the soft gamma-ray emission of the Milky Way

The Milky Way is known to be an abundant source of gamma-ray photons, now determined to be mainly diffuse in nature and resulting from interstellar processes. In the soft gamma-ray domain, point sources are expected to dominate, but the lack of sensitive high-resolution observations did not allow for a clear estimate of the contribution from such sources. Even the best imaging experiment revealed only a few point sources, accounting for about 50% of the total Galactic flux. Theoretical studies were unable to explain the remaining intense diffuse emission. Investigating the origin of the soft gamma-rays is therefore necessary to determine the dominant particle acceleration processes and to gain insights into the physical and chemical equilibrium of the interstellar medium. Here we report observations in the soft gamma-ray domain that reveal numerous compact sources. We show that these sources account for the entirety of the Milky Way's emission in soft gamma-rays, leaving at most a minor role for diffuse processes.     

产品所营造的个性化空间

从产品与空间的关系着手,分析了利用产品营造个性化空间的可能性,并在具体方法上作了初步探讨,以期为营造个性化空间提供新的视角和方法。