地震遥测数据传输中数字滤波器的实现

从理论上讨论了几种数字滤波器的工作原理及实现方法。着重分析了经典滤波器、统计滤波器和相关检测的工作原理,并给出了各滤波器系统的分析方法和传递函数,简化了数字滤波器的实现过程。为寻找到适合于地震数据传输的滤波方法做出了有益的探索。     

Analysis of Influences between the Energy Structure Change and Energy Intensity in China

In this article, based on the data of the energy statistics from 1980 to 2004, we analyze the relationship between the primary energy structures, technique, management, and the energy use per unit of GDP based on the path analysis approach and present the degree of the direct, indirect, and the overall influences of the primary energy structures on the energy use per unit of GDP. The results show that the technical change and management level play a decisive role in the energy use per unit of GDP, and the ratio of oil consumption was the major limiting factor to energy use per unit of GDP. We then found the model of the energy use per unit of GDP and the structures of the primary energy consumption, eliminated the multicollinearity in the model with the path analysis result, and finally, analyzed the influence of the primary energy structure on the energy conservation.     

Effects of Weighting Schemes on the Identification of Wildlife Corridors Generated with Least‐Cost Methods

The importance of movement corridors for maintaining connectivity within metapopulations of wild animals is a cornerstone of conservation. One common approach for determining corridor locations is least‐cost corridor (LCC) modeling, which uses algorithms within a geographic information system to search for routes with the lowest cumulative resistance between target locations on a landscape. However, the presentation of multiple LCCs that connect multiple locations generally assumes all corridors contribute equally to connectivity, regardless of the likelihood that animals will use them. Thus, LCCs may overemphasize seldom‐used longer routes and underemphasize more frequently used shorter routes. We hypothesize that, depending on conservation objectives and available biological information, weighting individual corridors on the basis of species‐specific movement, dispersal, or gene flow data may better identify effective corridors. We tested whether locations of key connectivity areas, defined as the highest 75th and 90th percentile cumulative weighted value of approximately 155,000 corridors, shift under different weighting scenarios. In addition, we quantified the amount and location of private land that intersect key connectivity areas under each weighting scheme. Some areas that appeared well connected when analyzed with unweighted corridors exhibited much less connectivity compared with weighting schemes that discount corridors with large effective distances. Furthermore, the amount and location of key connectivity areas that intersected private land varied among weighting schemes. We believe biological assumptions and conservation objectives should be explicitly incorporated to weight corridors when assessing landscape connectivity. These results are highly relevant to conservation planning because on the basis of recent interest by government agencies and nongovernmental organizations in maintaining and enhancing wildlife corridors, connectivity will likely be an important criterion for prioritization of land purchases and swaps. Efectos de los Esquemas de Ponderación sobre la Identificación de Corredores para Vida Silvestre Generados con Métodos Menos Costosos     

2 20 kV高压输电线电磁辐射水平及防护距离预测

依据<500 kV超高压送变电工程电磁辐射环境影响评价技术规范>(HJ/T 24-1998)中的预测模式对监测点周围地面1.5 m处工频电场进行了验证性监测,表明实际测定结果与理论计算结果基本吻合.通过对220 kV双回同相、双回逆相和单回线路下地面1.5 m、4.5 m、和7.5 m处工频电场变化趋势分析,预测了220 kV高压输电线产生的电磁辐射水平,以及不同房屋结构的防护距离.提出了220 kV高压输电线电磁辐射的防护措施.     

Impact and Dynamics of Disease in Species Threatened by the Amphibian Chytrid Fungus, Batrachochytrium dendrobatidis

Abstract:  Estimating disease-associated mortality and transmission processes is difficult in free-ranging wildlife but important for understanding disease impacts and dynamics and for informing management decisions. In a capture–mark–recapture study, we used a PCR-based diagnostic test in combination with multistate models to provide the first estimates of disease-associated mortality and detection, infection, and recovery rates for frogs endemically infected with the chytrid fungus Batrachochytrium dendrobatidis (Bd), which causes the pandemic amphibian disease chytridiomycosis. We found that endemic chytridiomycosis was associated with a substantial reduction (approximately 38%) in apparent monthly survival of the threatened rainforest treefrog Litoria pearsoniana despite a long period of coexistence (approximately 30 years); detection rate was not influenced by disease status; improved recovery and reduced infection rates correlated with decreased prevalence, which occurred when temperatures increased; and incorporating changes in individuals' infection status through time with multistate models increased effect size and support (98.6% vs. 71% of total support) for the presence of disease-associated mortality when compared with a Cormack–Jolly–Seber model in which infection status was restricted to the time of first capture. Our results indicate that amphibian populations can face significant ongoing pressure from chytridiomycosis long after epidemics associated with initial Bd invasions subside, an important consideration for the long-term conservation of many amphibian species worldwide. Our findings also improve confidence in estimates of disease prevalence in wild amphibians and provide a general framework for estimating parameters in epidemiological models for chytridiomycosis, an important step toward better understanding and management of this disease.     

试论环境空气质量自动监测系统的设计

目前 ,我国重点城市都在开展环境空气质量日报或预报工作 ,开展这一工作的基本条件之一是必须建立环境空气质量自动监测系统。由于我国目前的研制水平有限 ,空气质量自动监测系统基本上是靠引进国外技术及设备来完成的。而引进设备往往与我国的具体实际结合不够 ,尤其是在系统结构、数据采集、远程控制与诊断方面同我们的实际要求相去甚远。为此本文将围绕国内环境监测共同关注的环境空气质量自动监测系统及其设计的问题展开讨论 ,内容包括目前国内自动监测系统的现状 ;国外发展情况及趋势 ;自动监测系统结构与要求     

输油气站场综合风险评价技术研究

为完善国内输油气站场综合风险评价技术,提出一种站场综合风险评价模型。该模型基于模糊集理论,重点对传统的RCM与RBI技术进行改进与完善。将故障(失效)后果划分为伤亡后果、经济损失、环境影响和无形损失;采用模糊推理系统代替原有的算法进行计算设备风险,将动设备与静设备的风险转换为统一标度,得到站场综合风险值;最后采用雷达图显示站内设备的风险分布状况。实例分析表明,所建立的综合风险评价模型能够有效地解决定性风险与定量风险的融合问题,可为输油气站场的风险管理提供决策依据。     

基于FXLMS算法的矿用有源耳罩的研究

基于矿井中低频噪声突出,存在时间长、危害大,尤其周期性噪声比重较大,而传统降噪技术对其降噪效果并不明显,提出了基于fxlms 算法的自适应有源降噪耳罩降低矿井中的低频周期性信号,并采用离线建模方法建立了次级通道模型,利用MATLAB8.0拟合了64阶的滤波器,对 矿井中具有代表性的1kHz低频周期噪声和伴有随机噪声的1kHz低频周期性噪声进行了降噪仿真研究。结果表明:1kHz低频周期性噪声的降噪量 达到了30dB。而且在本模型下,随机噪声对低频周期性噪声的降噪效果几乎没有影响。     

土地供应计划对房价的传导机制研究

论文在借鉴四象限模型的基础上从理论上剖析了土地供应计划对房价的传导机制,并通过构建住房市场的存量-流量模型,利用湖南省2010-2013年14个市（州）的市本级面板数据,实证检验了土地供应计划对房价的传导机制。研究结果表明：土地供应计划的实施影响开发商预期,预期效应引致开发商的投机行为,进而对房价产生显著负影响,保障性住房用地占住宅用地的比例及供地计划实施率对房价产生显著负影响且影响强度不同,土地供应计划供地结构对房价的贡献大于计划实施率,该结论可为相关部门制定科学可行的供地计划提供重要决策参考。从单个因素分析,开发商的预期效应对房价波动的影响大于消费者预期效应对房价的影响;综合各需求面和供给面的因素分析,需求面因素对房价的影响程度大于供给面因素对房价的影响程度;上一期住房存量的增加进一步推动了房价的上涨。     

Numerical computation and characteristic analysis on the center shift of fire whirls in a ship engine room fire

The existence of fire whirls in some ship engine room is studied by using the basic elements of the fire whirls formation. The temperature characteristic of fire whirls are used to study the path shift of fire whirls and the result is nearly circular. The center shift angular velocity of fire whirls is analyzed with the least square fitting in the conditions of the constant wind velocity and the variable wind velocity from four sides. In the situation of the constant wind velocity, the result shows that the center shift angular velocity of fire whirls comply with the change regularity of a cube polynomial with different wind speed. When the wind velocity is more than 6.58 m/s, it strongly affects the change rate of the center shift angular velocity. However, in the situation of variable wind velocity, when the change rule of wind velocity follow increasing or descending regularity, the change law of the center shift angular velocity is proportional to the size of the wind velocity, but when the wind velocity is random variation, the change fluctuation of center shift angular velocity is comparatively small. Computational results have important significance for the structure fireproofing, fire evaluation and shipping design.