构筑企业级信息系统安全体系

本文以跨地区公司为例,探讨企业级信息系统安全体系的构筑,所述的原则和做法可以实现在外部网-内部网-主机-用户体系上,形成多道防线,使企业计算机网络具有相当程度的安全性,从而达到企业信息系统的安全目标。     

单线复用技术在水文巡测设备中的应用

为了解决水文巡测设备中数据传输的可靠性，电力载波通讯中的单频阻波器技术被应用到巡测设备上。此法简单易行，稳定可靠。     

油气沉积学原理及其在勘探开发中的应用

本文以油气藏形成条件中的生、储、盖、运、圈为纲讨论了油气勘探沉积学;以油气藏开发过程中与沉积、成岩的关系讨论了油气开发沉积学。在油气勘探沉积学中重点论述了陆相沉积与储层及圈闭的关系;在油气开发沉积学中重点论述了储层研究的基础—储层的沉积属性和成岩特征。强调储层沉积、成岩研究应成为储层评价最重要的内容。     

The stability robustness determination of state space models with real unstructured perturbations

This paper considers the robust stability of a linear time-invariant state space model subject to real parameter perturbations. The problem is to find the distance of a given stable matrix from the set of unstable matrices. A new method, based on the properties of the Kronecker sum and two other composite matrices, is developed to study this problem; this new method makes it possible to distinguish real perturbations from complex ones. Although a procedure to find the exact value of the distance is still not available, some explicit lower bounds on the distance are obtained. The bounds are applicable only for the case of real plant perturbations, and are easy to compute numerically; if the matrix is large in size, an iterative procedure is given to compute the bounds. Various examples including a 46th-order spacecraft system are given to illustrate the results obtained. The examples show that the new bounds obtained can have an arbitrary degree of improvement over previously reported ones. This work has been supported by the Natural Sciences and Engineering Research Council of Canada under Grant No. A4396.     

Network model approach for calculating oscillating frequency of thermoacoustic prime mover

The network model is given and used to calculate the oscillating frequency of thermoacoustic prime mover. Theoretically calculated frequency by the model is plural, whose real part denotes actual frequency of the system, and imaginary part means attenuation coefficient of acoustic pressure. Numerical calculation is made under different conditions including different acoustic cavities, spacing between each parallel plate, gas pressures and system lengths. Theoretically calculated frequency and experimentally measured frequency are in quite good agreement.     

潮汐河口平面二维非恒定流数值模拟

本文基于三角形网格划分，采用有限元法，建立了平面二维非恒定潮流数学模型。采用了质量集中、压缩存储的处理方法和“预估校正”的时间推进算法，较好地解决了有限元计算存储量和计算速度问题。对长江口南北支河段进行了验证计算，结果表明模型能较好模拟长江口南北支河段的潮流运动情况，且计算稳定性好、速度快、精度高。     

A quantitative method for evaluating the performances of hyperspectral image fusion

Hyperspectral image fusion is a key technique of hyperspectral data processing. In recent years, many fusion methods have been proposed, but there is little work concerning evaluation of the performances of different image fusion methods. In this paper, a method called quantitative correlation analysis (QCA) is proposed, which provides a quantitative measure of the information transferred by an image fusion technique into the output image. Using the proposed method, the performances of different image fusion methods can be compared and analyzed directly based on the images of before and after performing the fusion. The correlation information entropy, based on the developed QCA, is also proposed and testified by numerical simulations. Typical hyperspectral data are applied to the proposed method. The results show that the method is effective, and its conclusions agree with the classification results in applications.     

建立五大创新体系促进绿色建筑发展

我们正站在一个新的历史起点上,同时处在一个非常重要的关口。在世界范围内,以大量消耗原材料和能源为特征的传统经济正在逐渐失去昔日的荣耀。由资源依赖型转向创新驱动型,真正实现经济增长方式的转变,已成为正处于快速城镇化、工业化与机动化进程之中的我国经济发展面临的非常迫切的重大战略选择。在未来30年内,我国还需建造400亿m2的新建筑,建筑数量和建设速度都是世界发展史上所罕见的。建筑属于长期的消费品,不可能进行频繁的更新。仅延长建筑使用寿命或装修期限,就意味着能源和资源的大量节约与环境污染的减少。绿色建筑是指为人们提…     

Nd3+ Doped Silicate Glass Photonic Crystal Fiber with Random Hole Distributions

The fabrication of one kind of large core area Nd3 doped silicate glass photonic crystal fiber, and demonstration of the fiber's waveguidence properties were reported. This fiber owns a random air hole distribution in the cladding. The measured minimum loss of this kind of fiber is 10 dB·m-1 at 660 nm. These fibers can sustain only a single mode at least over wavelength ranging from 660 nm to 980 nm.