1.5 μm波长n-p-n型InGaAsP-InP晶体管激光器材料外延生长

基于器件模拟仿真,设计了一种1.5 μm波长InGaAsP-InP晶体管激光器材料外延结构. 其多量子阱有源区置于基区非对称波导中. 仿真结果显示该外延结构能够获得较好的光场限制和侧向电流限制. 对该材料MOCVD生长研究表明,基极重掺杂接触层中Zn²⁺扩散将导致量子阱严重退化. 通过对其扩散过程的模拟仿真,采用平均掺杂浓度为1×10¹⁸ cm^-3的梯度掺杂,有效地抑制了Zn²⁺向量子阱区的扩散. 所获得的外延材料在     

锆石中磷的分带趋势、成因及地质意义

本文用电子探针对岩浆和变质重结晶锆石进行了成份分带的研究，结果表明，变质重结晶锆石具有从晶体中心至边缘Ｐ２Ｏ５含量增大的特点，可作为它们的成因标型特征，岩浆锆石则Ｐ２Ｏ５含量变化不稳定，本文论述了它们的成因。     

Relationships between fractal road and drainage networks in Wuling mountainous area: Another symmetric understanding of human-environment relations

Symmetrical relationships between humans and their environment have been referred to as an extension of symmetries in the human geographical system and have drawn great attention. This paper explored the symmetry between physical and human systems through fractal analysis of the road and drainage networks in Wuling mountainous area. We found that both the road and drainage networks reflect weak clustering distributions. The evolution of the road network shared a significant self-organizing composition, while the drainage network showed obvious double fraetal characteristics. The geometric fractal dimension of the road network was larger than that of the drainage network. In addition, when assigned a weight relating to hierarchy or length, neither the road network nor drainage network showed a fractal property. These findings indicated that the fractal evolution of the road network shared certain similarities with fractal distribution of the drainage network. The symmetry between the two systems resulted from an interactive process of destroying symmetry at the lower order and reconstructing symmetry at the higher order. The relationships between the fractal dimensions of the rural-urban road network, the drainage network andthe urban system indicated that the development of this area was to achieve the symmetrical isomorphism of physical-human geographical systems.     

Spatio-temporal evolution of urban innovation structure based on zip code geodatabase: An empirical study from Shanghai and Beijing

In today’s world, the innovation of science and technology has become the key support for improving comprehensive national strength and changing the mode of social production and lifestyle. The country that possesses world-class scientific and technological innovation cities maximizes the attraction of global innovation factors and wins a strategic initiative in international competition. Based on the urban zip code geodatabase, an evaluation system of urban innovation with the perspective of innovation outputs, and the spatial evolutionary mode, concerning the structure of innovation space of Shanghai and Beijing from 1991 to 2014, was developed. The results of the research indicated that the zip code geodatabase provided a new perspective for studying the evolving spatial structure of urban innovation. The resulting evaluation of the spatial structure of urban innovation using the urban zip code geodatabase established by connecting random edge points, was relatively effective. The study illustrates the value of this methodology. During the study period, the spatial structure of innovation of Shanghai and Beijing demonstrated many common features: with the increase in urban space units participating in innovation year by year, the overall gap of regional innovation outputs has narrowed, and the trend towards spatial agglomeration has strengthened. The evolving spatial structure of innovation of Shanghai and Beijing demonstrated differences between the common features during the 25 years as well: in the trend towards the suburbanization of innovation resources, the spatial structure of innovation of Shanghai evolved from a single-core to a multi-core structure. A radiation effect related to traffic arteries as spatial diffusion corridors was prominent. Accordingly, a spatial correlation effect of its innovation outputs also indicated a hollowness in the city center; the spatial structure of innovation of Beijing had a single-core oriented structure all the way. Together with the tendency for innovation resources to be agglomerated in the city center, the spatial correlation effect of innovation outputs reflected the characteristics of the evolutionary feature where “rural area encircles cities”. The innovation spatial structure of Shanghai and Beijing have intrinsic consistency with the spatial structure of their respective regions (Yangtze River Delta urban agglomeration and Beijing-Tianjin-Hebei metropolitan region), which suggested that the principle of proportional and disproportional distribution of a city-scale pattern of technological and innovational activities is closely related to its regional innovation pattern.     

基于GIS城市给排水管网信息系统数据结构的研究与实现

本文研究了城市给排水管网信息系统的数据结构及其建立方法,以及在微机上利用C语言进行城市给排水信息系统的设计,实现了部分空间分析功能。     

Long-term simulations of the sulfur concentrations over the China, Japan and Korea: A model comparison study

Three comprehensive acid deposition models were used to simulate the sulfur concentrations over northeast Asia over the period covering entire year of 2002, and discussed the aggregated uncertainties and discrepancies of the three models. The participating models are from the countries participating in the project of Longrange Transboundary Air Pollutants in Northeast Asia (LTP): China, Japan and Korea. The Eulerian Model-3/CMAQ (by China), Regional Air Quality Model (RAQM, by Japan), and Comprehensive Acid Deposition Model (CADM, by Korea) were employed by each country with common emissions data established by the administrative agencies of China, Japan and Korea. The episodic simulation results between 1 to 15, March 2002 are also presented, during which aircraft measurements were carried out over the Yellow sea. The episodic results show both a wide short-term variability in simulations against measurements, and maximum concentration differences of 3～5 times among the three models, requiring that further attention before confidence among the three models can be claimed for short-term simulations. However, the year-long cumulative simulations showed almost the same general features, with lower aggregated uncertainties between the three models, produced by the long term integration over northeast Asia.     

全球板块运动背景场及ITRF2005VEL的建立

简要分析了最新的国际地球参考框架ITRF2005实现的基本情况及其相对于ITRF2000的改进,以ITRF2005为参考框架建立了新的全球板块运动模型ITRF2005VEL。建模时,首先根据测站的分布和速度场的精度对测站进行初步剔除,然后采用相似变换的方法对全球ITRF2005测站的速度场数据再进行第2次筛选。根据筛选结果利用最小二乘方法建立了全球板块运动背景场及其运动模型,给出了全球11个主要块体的运动参数。此结果与其他学者建立的模型相比,总体上有很好的一致性,但在个别块体上也有所差异。     

测绘职业教育教学改革探讨

随着空间科学技术和计算机技术的发展，以“3S”技术为代表的测绘高新技术已普遍应用于测绘生产中。作为培养测绘实用型人才的测绘职业学校，测绘专业如何重新划分、测绘教育与教学内容如何改革，是测绘教育界普遍关注的问题，本文从教学的角度对有关问题进行了探讨。     

Authorization administration in a distributed multi-application environment

To meet the authorization administration requirements in a distributed computer network environment, this paper extends the role-based access control model with multiple application dimensions and establishes a new access control model ED-RBAC(Extended Role Based Access Control Model) for the distributed environment. We propose an extendable hierarchical authorization assignment framework and design effective role-registering, role-applying and role-assigning protocol with symmetric and asymmetric cryptographic systems. The model can be used to simplify authorization administration in a distributed environment with multiple applications.