制冷控制系统研制与探析

根据实际应用研制制冷控制系统,该系统采用温度测量、PID控制及PWM脉宽调制等技术实现了对目标对象的制冷处理,具有一定的应用价值。     

宏观生态环境遥感监测系统总体设计与关键技术

宏观生态环境遥感监测系统是基于环境遥感监测应用技术的软件实现.本文重点介绍了宏观生态环境遥感监测系统的总体结构设计、业务流程设计和核心功能设计,以及模型转换与实现技术、实时投影转换技术与以文件和数据库相结合的数据管理技术、基于XML的数据实时交换技术、产品自动化生产技术等关键技术,并给出了系统的应用实例.系统应用结果表...     

MONITORING POLYNUCLEAR AROMATIC HYDROCARBONS IN SEDIMENT POREWATER BY SPMD

A new mimic biological Semi-permeable Membrane Device (SPMD) introduced for sampling organic pollutants yielded satisfactory results when it was frrst used as a passive sampler to concentrate and determine 16 kinds of polynuclear aromatic hydrocarbons (PAHs) by means of capillary GC on an HP 5890 GC-FID in coastal sediment perewater. The concentration of PAHs in sediment porewater for naphthalene(N), acenaphthlene(AL), acenaphthene (AE), fluorene (F), phenaphthene(P), anthracene(A), fluoranthene(FA), pyrene(Py), benzo[a]anthracene(B[a]A), chrysene(Chr), benzo[b] fluor- anthene(B[b]F), benzo[k]fluoranthene(B[k]F), benzo[a]pyrene(B[a]P),indeno[1,2,3,-cd]-Pyrene(I[123]P), dibenz[a,h]anthracene(D[ab]A) and benzo[g,h,i] perylene(B[ghi]P) were:50.36, under detection limits(UD), 18.19, 8.41, 8.40, 1.44, UD, 8.01, 524.15, 168.47, 50.13,123.66, 63.48, 27.40, 82.04 and 58,81 ng/L, respectively.     

水下溢油数值模拟研究

基于Lagrange积分法和Lagrange粒子追踪法建立了一个水下溢油数值模型。该溢油模型由两个子模型组成:羽流动力模型和对流扩散模型,其中羽流动力模型用以模拟溢油的喷发阶段和浮力羽流阶段;对流扩散模型用以模拟溢油的对流扩散阶段。通过数值实验,结合实验室水槽实验和水下溢油现场实验的观测资料进行模型验证。实验结果表明,模拟结果与观测资料一致性较好,从而验证了本文溢油模型的合理性和准确性;羽流动力模型为对流扩散模型提供源,海流、海水的垂向密度结构和油滴的直径分布是影响溢油在对流扩散阶段运动和分布的主要因素。     

Quantifying the effects of climate variability and human activities on runoff from the Laohahe basin in northern China using three different methods

Much attention has recently been focused on the effects that climate variability and human activities have had on runoff. In this study, these effects are quantified using three methods, namely, multi‐regression, hydrologic sensitivity analysis, and hydrologic model simulation. A conceptual framework is defined to separate the effects. As an example, the change in annual runoff from the semiarid Laohahe basin (18 112 km²) in northern China was investigated. Non‐parametric Mann‐Kendall test, Pettitt test, and precipitation‐runoff double cumulative curve method were adopted to identify the trends and change‐points in the annual runoff from 1964 to 2008 by first dividing the long‐term runoff series into a natural period (1964–1979) and a human‐induced period (1980–2008). Then the three quantifying methods were calibrated and calculated, and they provided consistent estimates of the percentage change in mean annual runoff for the human‐induced period. In 1980–2008, human activities were the main factors that reduced runoff with contributions of 89–93%, while the reduction percentages due to changes in precipitation and potential evapotranspiration only ranged from 7 to 11%. For the various effects at different durations, human activities were the main reasons runoff decreased during the two drier periods of 1980–1989 and 2000–2008. Increased runoff during the wetter period of 1990–1999 is mainly attributed to climate variability. This study quantitatively separates the effects of climate variability and human activities on runoff, which can serve as a reference for regional water resources assessment and management. Copyright © 2011 John Wiley & Sons, Ltd.     

一种混合数据加密方法探讨

对高级数据加密标准（AES）和RSA两种数据加密算法进行了介绍和比较。通过横向混合，进行了编码设计的一种探索，分析新编码方式的特点和安全性并进行了软件实现。     

凸度量空间中渐近拟非扩张映象新的带误差的Ishikawa迭代逼近

在凸度量空间中，利用新的解析法，征明了由集合序列{On}产生的在多值渐近拟非扩张映象下的新的带误差的lshikawa迭代序列的收敛性。     

基于移动Agent的网格资源信息管理

资源管理是网格中间件的重要组成部分，负责对网格资源进行组织、分配、调度。其中资源信息管理是资源管理的基础，关系到资源分配、调度的效率，进而影响网格的整体性能。分析了现有的网格资源信息管理技术，提出了基于移动Agent的资源信息管理模型。     

月球重力场对绕月低轨卫星的长期影响

从解析形式出发,利用月球重力场模型JGL165P1,分析了月球重力场(带谐项)对绕月低轨卫星的长期影响。为了减少计算误差,保证计算精度,在分析解中使用循环公式来计算倾角函数。结果指出对于一个高度为100km的极月轨道卫星,冻结轨道存在的可能性不大,但是当轨道倾角在i=90°附近或者高度再高一些,则有可能存在冻结轨道;对于100km高的初始圆轨道,卫星在无控的情况下半年内将会坠落到月球表面,如果高度增加到200km,则不进行轨道控制也不会坠落到月面上。利用仿真软件GEODYN解算出来的结果证实了上述结论。     

城市3维地理信息系统中场景的制图输出技术

针对当前城市3维地理信息系统中制图输出精度受帧缓冲大小限制的问题,提出一种内容分块输出、图像自动合并的高分辨率制图输出方法。针对平行投影和透视投影,分别阐述制图输出的技术原理和实现步骤。实践表明,这种制图输出技术不但可以有效地解决3维场景高精度打印输出的难题,还可以为场景效果图的网络发布提供基本的素材。