西藏阿里地区的林业资源及其发展方向探讨

该文对西藏阿里地区林业资源的类型、数量、质量特征和生产现状进行了深入分析,同时,探讨了该地区林业生产存在的“资源结构简单、后续资源极端贫乏;资源分布不均,水平和垂直分异突出;宜林荒山荒地资源面积大,造林任务艰巨、生态环境破坏严重”等主要问题,提出了如下的对策和建议:①健全林业行政管理体制,加强林业资源管理;②节省薪柴,保护生态环境;③实行林地承包制,大力兴办林业;④加强林业科技投入,以科技兴林,走林业可持续发展之路。     

两个相邻高建筑物周围的风环境

描述研究了建筑物周围人行道高度风速分布特征的风洞模拟实验。结果表明：在一个横风向宽度很大的高大建筑物的迎风面拐角附近，风速增大约１倍；而在建筑物的前方有风速的骤变区，这均形成严重的风环境问题。当用一通道将该建筑物分割成两个相邻建筑物时，上述两方面的风环境问题得到了有效的改善，且通道宽度与建筑物顺风向尺度之比的优化数值在１８至２４之间     

环境保护执法新探

环境执法的方式、手段起到优化作用.随着环境立法的完备和社会公众对环境质量要求的提高.如何加强环境执法的力度、改变环境执法的方式和执法领域.只有严格的执法才能保证和刺激政府、企业对环境服务的需求.通过建立完备的环境执法体系,坚决做到有法可依、有法必依、执法必严.以法规的形式,进一步明确环境保护行政主管部门的执法主体地位,调整和强化环保行政主管部门的管理职责,加大统一监管力度.做到法定执法权限,公开执法程序,明晰执法责任,规范执法行为.文章通过分析现行环境执法的缺陷,提出中国环境执法的优化目标和方向.     

赣南W、Sn多金属成矿区划及找矿方向

赣南地区是南岭成矿区(带)中重要的W、Sn多金属矿产聚集地,已探明黑钨矿储量和产量均居世界第一。区内主要矿化元素为W、Sn、Pb、Zn、Ag、Au、Nb、Ta、Mn等。主要矿化类型为石英脉型、破碎蚀变岩型钨矿,斑岩型、层间隐爆裂隙带型锡矿,隐爆角砾岩型铜矿,形成了与燕山期岩浆活动有关的钨锡多金属成矿系列。新矿化类型是赣南中生代岩浆—火山岩区找矿的重要方向。     

低层大气中固体粒子运动及其物理模拟

对于大气边界层中的固体粒子的风致运动－较大粒子的蠕动跃动和较小粒子悬浮－的主要特征作了介绍，着重介绍了在悬浮粒子运动的物理模拟研究方面的一些成果；复杂地形物低层大气湍流会显地提高起尘速率并改变降尘量的分布；有一定我向厚度的风障除了屏蔽效应－－即背风侧平均风速的减小－－外，还滕了终进入空气的灰尘数量的“宏观吸附效应”；总结了模拟悬浮粒子运动的风洞实验所应遵循的相似性准则，并提出了模拟防尘风障的中的     

Wind Tunnel Experiments and Numerical Simulation of Snow Drifting around an Avalanche Protecting Dam

To learn about wind flow and snow drifting around avalanche dams, experiments were done in the Jules Verne Climatic Wind Tunnel. The paper reports the results from numerical wind flow simulations that were done to support the findings from the wind tunnel. Satisfying the model similitude criteria for the wind tunnel configuration was difficult due to the inevitable small geometric scale of the model, while on the contrary the snow drifting conditions in the facilities were full scale. By comparing numerical wind flow results of full scale and model scale dams with the snow pattern observed in the wind tunnel, it was possible to conclude that albeit poor model similitude, the snowdrifts on the windward side of the wind tunnel model are likely to indicate the full scale natural situation.     

Weak-wind mesoscale meandering in the nocturnal boundary layer

This study examines the strength and statistical behavior of mesoscale motions on time scales up to 1 h using eight data sets over different surface types. The mesoscale motions include internal gravity waves, microfront-like structures, horizontal modes, and a complex variety of other signatures, perhaps resulting from superposition of different modes. With weak large-scale flow, the mesoscale motions lead to meandering of the wind direction, as found in previous studies. However, the meandering often takes the form of sudden wind shifts rather than oscillation of wind direction. The relative strength and impact of such mesoscale motions are examined in terms of the constancy of the wind vector, the within-record standard deviation of the wind direction and the ratio of a meso-velocity scale to the speed of the large-scale flow. The strength of the mesoscale flow varies by an order of magnitude between nights at a given site and varies systematically between sites. The statistics of the vertical structure of such motions are examined for two of the data sets, both with sonic anemometers at seven levels.     

Estimation of the surface stress from the streamwise pressure gradient: The Kármán Integral Momentum Equation revisited

A method is developed to estimate the stress at the surface in a portable wind tunnel for wind erosion studies. The boundary layer height and the pressure gradient are used in a simple expression from the Kármán Integral Momentum Equation. Values of friction velocity u _* are within 10% of experimental values obtained through correlation techniques, including measurements of differential pressures with the Murdoch Turbulence Probe MTP and the X-wire, hot-wire anemometer XWA. Wind velocity and stress profiles reveal logarithmic trends and a constant stress layer near the surface in the DAWA portable wind tunnel. Realignment of the statistics with the mean wind is essential.     

气象条件对可吸入颗粒物浓度的影响

气象条件对可吸入颗粒物浓度有较大的影响,通过对鞍山市二年来的监测数据进行分析,得出了结论并提出建议.     

室内废气污染的计算与分析

通过对吸油烟机抽吸风场有效强度矢量图的测量 ,给出了吸油烟机质量技术检验方法和油烟废气、燃气废气污染泄漏量的计算方法 ;对油烟、燃气废气在厨房的扩散与循环作了详细分析 ,并对国标提出几点建议。