Analyses of airborne Be concentrations in Hong Kong using back-trajectories

A total of 71 air samples were collected in Hong Kong area from November 2001 to February 2003 using a high-volume air sampler and a high-volume cascade impactor with five atmospheric pressure stages. The ⁷Be radioactivity on each stage was measured using a high-efficiency germanium gamma-ray spectrometer. From the radioactivity of stages, the total airborne ⁷Be radioactivity was determined. The activity median aerodynamic diameter (AMAD) of ⁷Be-associated atmospheric aerosols was found to be 0.22–1.11 μm and the geometric standard deviation (GSD) was found to be 1.2–10.5. With the assumed mean growth rate (MGR) of atmospheric aerosols of 0.004–0.005 μm h⁻¹ and the size of Aitken nuclei of 0.015 μm, the residence times of ⁷Be-associated atmospheric aerosols were also found from the AMAD.Three-dimensional 4-day back-trajectories were obtained using the HYSPLIT model from NOAA Air Resources Laboratory. These trajectories were used with the measured ⁷Be radioactivity to construct regional ⁷Be intensity fields for four different altitude levels (less than 1000, 1000–2000, 2000–3000 and above 3000 m) with a Geographic Information System (GIS). Low ⁷Be intensities were found to have advected from low altitudes (less than 1000 m) and oceanic areas. The ⁷Be intensities increased for the higher intensity field layers.By comparing the time taken for air masses to come from the ⁷Be source to Hong Kong and the residence time determined from the AMAD of ⁷Be-associated atmospheric aerosols, good agreement was found if the mean growth rate of 0.005 μm h⁻¹ for atmospheric aerosols was used, and the use of back-trajectories was shown to be satisfactory even up to about 6.5 d. By using the residence time with a MGR of 0.005 μm h⁻¹, the ⁷Be source was found to be relatively well confined in the areas of Mongolia and southeastern Siberia, which further supported that the association of ⁷Be source with the Siberian anticyclone.     

论环境—经济系统协调度

以持续发展理论为核心，以环境－经济系统为研究对象，借助系统工程多目标技术和协同论的观点，建立了环境－经济系统协调度模型。模型分为３个部分，功效函数，协调度函数和环境－经济系统指标体系。模型正确与否关键在于功效函数中的上下限值和指标体系中指标的选取，这两项因子的确定可以参照应用地区的实际情况和因子数据的可获得性来确定，最后应用此模型分析了某市环境－经济系统协调度现状及变化趋势。     

酒精企业清洁生产的系统仿真及政策调控

酒精企业的清洁生产涉及到工艺流程的改进、循环冷却水、糟泥等的资源化利用等各方面,是一个复杂的反馈系统.采用系统动力学模型,运用DYNAMO语言,以某酒精制造企业的清洁生产为例进行仿真模拟,通过调控煤炭价格、水资源费、排污费以及沼气、糟泥等的不同利用方式等参数提出优选方案,分析提高该厂在推进清洁生产的不同方案下的经济效益,为该企业实施清洁生产方案的优化提供决策依据,为政府进行政策制定提供相关建议.     

基塘系统：研究回顾与展望

基塘系统是一种具有独特创造性的低洼土地利用方式和生态循环农业模式,在中国小农经济时期发挥了重要作用。20世纪50年代以来基塘系统逐渐受到学界重视,并曾引起国内外的广泛关注。当前系统梳理和总结基塘系统研究进展,对我国相关重要农业文化遗产的保护与现代高效生态农业发展具有重要支撑意义。论文基于基塘系统主要公开文献,从基塘系统的概念内涵、起源演变、结构功能、推广应用、动态保护等方面介绍国内外研究进展。资料分析显示：相对太湖流域基塘系统,针对珠江三角洲基塘系统的研究更为丰富;有关太湖流域桑基鱼塘起源的论证还存在分歧;基塘系统的经济功能衰退,其生态服务功能和遗产文化价值研究急需加强;传统基塘农业保护与创新发展还需加强技术、管理、政策等方面研究的支持。未来值得重视的研究方向有：1）加强对基塘系统生态服务功能研究,更全面客观地评估基塘系统的综合效益;2）基于农业文化遗产视角,开展基塘系统的动态保护与适应性管理研究;3）多学科深入研究基塘系统的作用机理,更好地总结与比较太湖流域与珠江三角洲基塘系统结构功能的异同;4）深入论证基塘系统的起源与演变过程,明确它在中国和全球农业史中的重要地位。     

Correlation between crash avoidance maneuvers and injury severity sustained by motorcyclists in single-vehicle crashes

Objectives: In order to improve motorcycle safety, this article examines the correlation between crash avoidance maneuvers and injury severity sustained by motorcyclists, under multiple precrash conditions. Method: Ten-year crash data for single-vehicle motorcycle crashes from the General Estimates Systems (GES) were analyzed, using partial proportional odds models (i.e., generalized ordered logit models). Results: The modeling results show that “braking (no lock-up)” is associated with a higher probability of increased severity, whereas “braking (lock-up)” is associated with a higher probability of decreased severity, under all precrash conditions. “Steering” is associated with a higher probability of reduced injury severity when other vehicles are encroaching, whereas it is correlated with high injury severity under other conditions. “Braking and steering” is significantly associated with a higher probability of low severity under “animal encounter and object presence,” whereas it is surprisingly correlated with high injury severity when motorcycles are traveling off the edge of the road. The results also show that a large number of motorcyclists did not perform any crash avoidance maneuvers or conducted crash avoidance maneuvers that are significantly associated with high injury severity. Conclusions: In general, this study suggests that precrash maneuvers are an important factor associated with motorcyclists' injury severity. To improve motorcycle safety, training/educational programs should be considered to improve safety awareness and adjust driving habits of motorcyclists. Antilock brakes and such systems are also promising, because they could effectively prevent brake lock-up and assist motorcyclists in maneuvering during critical conditions. This study also provides valuable information for the design of motorcycle training curriculum.     

大型游艺机——过山车的安全性分析

研究基于虚拟样机技术的过山车的安全性问题,旨在解决传统设计的弊端,有效降低设计成本,提高过山车的安全性能。在ADAMS软件中建立过山车的虚拟样机模型。研究轨道圆环直径、车厢重量、制动力对过山车安全性能的影响,获得以上各参数的合理范围,使车厢连接副受力状况与加速度得到改善,制动力精确性得到提高。为探索运动类特种设备———过山车的安全保障技术提供了新途径。     

基于全球定位系统(GPS)的电动车辆实时监控系统设计

电动汽车以其良好的环保效应和灵活多样的能源利用形式,已成为国际社会普遍公认的汽车工业的重要发展方向之一,作为凸显可持续发展理念和国家科技产业实力的窗口,电动汽车的规模化应用将成为彰显2008北京“绿色奥运、科技奥运”主题的鲜明标志。为确保电动汽车奥运应用的安全性与可靠性,笔者提出了基于GPS的电动车辆实时监控系统的总体设计。该系统由车载信息采集终端(OBICT)、车辆运行监控(VOP)和无线通讯网络(WCN)3个子系统构成,并能对电动汽车运行中的电池及关键部件工作状态、车辆位置等数据进行实时采集与传输。在给出系统总体结构设计的基础上,对该车载信息采集终端、车辆运行监控子系统的数据流程进行分析,并提出了相应的软/硬件架构技术、设计方法以及实现的功能。     

特种劳动防护用品安全标识监管与防伪系统的开发及应用

本系统将特种劳动防护用品在日常管理过程中出现的大量繁杂多变的信息转变为数字信息数据，并建立适当的数学模型，由计算机对模型进行综合分析处理，同时显示结果，从而实现特种劳动防护用品的数字化管理，实现产品的真伪辨别和产品质量的责任追溯。     

GIS‐BASED WATER QUALITY MODELING IN THE SANDUSKY WATERSHED,OHIO, USA1

ABSTRACT: This study focused on the Sandusky Watershed (SW) in Ohio, located within the Great Lakes Basin, with emphasis on two of its subwatersheds, namely Honey Creek (HC) and Rock Creek (RC). The goal was to assess the capabilities of the Soil and Water Assessment Tool (SWAT) to simulate suspended sediment (SS), phosphorus (P) and nitrogen (N) yield in the SW that contribute major sediment and nutrient loads into Lake Erie. The model was calibrated using water flow and water quality parameters for water years 1998 to 1999 and validated model simulations covering the period of water years 2000 to 2001 for monthly conditions. The validation of SS showed correlation coefficients of 0.29 (SW), 0.75 (HC) and 0.69 (RC). Correlation coefficients for P were 0.68 (SW), 0.78 (HC) and 0.37 (RC); for N0₂‐N 0.84 (HC) and 0.38 (RC); for N0₃‐N 0.27 (HC) and 0.76 (RC); for NH₃‐N 0.57 (SW), 0.49 (HC), and 0.13 (RC). In addition, mean errors, root mean square errors, Nash‐Sutcliffe coefficients, and graphs were used to compare simulated to measured data. Simulation success was variable with poor and good simulations, but in most cases, simulated water quality values followed the trend of measured data except for extreme (or intense) rainfall/runoff events. Reviews of 17 applications indicated that the SWAT is suitable for long term continuous simulations but not for storm events. A spatially distributed modeling approach generated maps showing the spatial distribution of SS, P, and N for each simulation element across the Sandusky Watershed.     

空间信息技术在防震减灾工作中的作用

我国是个地震多发国家，地震损失严重。在防震减灾研究中，迫切要求引进先进的科学技术手段，用高新技术推动防震减灾工作的发展。目前遥感技术、地理信息系统和全球定位系统（合称3S）得到了快速发展，以3S技术为主要框架的空间信息技术在防震减灾领域得到了广泛的应用。本文重点阐述了空间信息技术在防震减灾中的作用，并对空间信息技术在防震减灾中的应用趋势作出展望。