明渠潮流中垂向紊动射流流场的数值模拟

选用ｋ－ε双方程紊流模型，对自由水面做“动”刚盖假设，建立了明渠潮流中垂向射流流场的数学模型，根据潮汐流动返复回荡的特点，对离散方程组的求解采用“跟踪扫描”逐行求解法，保护和加快了解的收敛，计算了５种不同回荡周期情况下射流流场的变化过程，预报回流区高度与实测值吻合。分析了潮汐非恒定性的影响，获得了一些有益的结论。     

Fe3+催化氧化S(Ⅳ)反应机理初探

通过分析酸性条件下(pH为1～3),Fe3 催化氧化S(Ⅳ)过程中溶液吸光度变化的趋势,对Fe3 催化氧化S(Ⅳ)的反应机理进行了初步推导.实验证明,液相中该反应机理主要是催化氧化与自由基反应相结合,O2的存在对于反应有重要作用,O-2的生成是S(Ⅳ)被氧化的关键;当水中溶解氧接近耗尽时,反应进程发生改变.当Fe3 、S(Ⅳ)浓度增加,自由基生成量增加时,有利于反应进行;作为反应产物,Fe2 、S(Ⅵ)浓度增加,反应推动力减小,反应速率降低;同时Fe2 、SO24-可以与溶液中的其它物质形成配合物,影响了Fe3 -S(Ⅳ)配合物的生成与分解,不利于S(Ⅵ)的氧化.     

汽车内二氧化碳污染与通风模式

不同车速下,对四种通风模式(A关闭通风口和风扇、B关闭通风口打开风扇、C打开通风口关闭风扇、D打开通风口和风扇)车内二氧化碳浓度进行分析研究。通风口关闭的状态,无论是否打开风扇及车速快慢,车内CO2浓度严重超标。通风口打开:不开风扇,以50km/h速度行驶,车内CO2浓度高于标准限量;速度提高到80km/h,车内CO2浓度可低于标准限量,通风口和缝隙的换气可以保障车内的空气质量;而打开风扇可以有效排除车内污染物。车速提高,各种通风模式的换气量都增加,属于缝隙换气贡献的比例增加,属于风扇换气贡献的比例减小,属于通风口换气贡献比例变化不大。基于研究结果,提出了一些减少车内污染的通风方式建议。     

关于促进我国循环经济法制建设的思考

循环经济作为一种有效平衡经济增长,社会发展和环境保护三者关系的全新经济模式,在我国的发展已是大势所趋.而这一系统工程建立的基础是相关法律法规的建立.目前,许多发达国家已经以立法的方法来保障循环型社会的建立和发展.加快我国循环经济法制建设需要对循环经济的内涵,发达国家的循环经济立法,我国循环经济法制建设的实践及其存在的问题进行系统研究,根据我国的实际情况,得出对中国的循环经济立法具有针对性的建议,在依法治国的当今中国,以法律形式对循环经济加以肯定和规范具有重要意义.     

昆明市自然保护区可持续发展对策探讨

昆明市7个自然保护区存在管理机构不健全、体制不顺、基础工作薄弱、经费不足和保护与开发矛盾突出等问题。应加强立法、建立条块相互协调的管理机制,建立保护区经济补偿机制,加强规划,增加投入,改善基础设施,以实现自然保护区的可持续发展。     

元磨高速公路边坡生物防护技术研究

对云南元磨高速公路的边坡生物防护的植物筛选技术和施工工艺进行了研究。试验探索了湿法喷播中草灌的比例问题，发现了短萼灰叶(山毛豆)是适宜的灌木种，并提出了“两步施工法”。     

昆明空气污染物等级与天气背景的关系

通过样本分析得出：昆明空气污染物主要为SO2,为轻度污染;秋冬季出现污染日较多,可分为高压脊控制型和偏西气流型天气背景。夏季出现污染日较少,主要为高压脊控制型天气背景;污染物浓度在一天中的分布特征呈“W”型;污染物预报方程。     

Spatial variations in daily average CO2 concentrations above wetland surface of Xianghai National Nature Reserve, China

Horizontal and vertical variations of daily average CO2 concentration above the wetland surface were studied in Xianghai National Nature Reserve of China in August, 2000. The primary purpose was to study spatial distribution characteristics of CO2 concentration on the four levels of height(0.1 m, 0.6 m, 1.2 m and 2 m) and compare the differences of CO2 concentration under different land covers. Results showed that daily average CO2 concentration above wetland surface in Xianghai National Natural Reserve was lower than that above other wetlands in northeast China as well as the worldwide average, suggesting that Xianghai wetland absorbed CO2 in August and acted as“sink” of CO2. The horizontal variations on the four levels of height along the latitude were distinct, and had the changing tendency of“decreasing after increasing” with the increase of height. The areas with obvious variations were consistent on different levels of height,and those with the highest variations appeared above surface of shore, sloping field, Typha wetland and Phragmites wetland; the vertical variations were greatly different, with the higher variations in Phragmites wetland and Typha wetland, and the lands near the shore and the sloping field with the lower variations. Spatial variations of daily average CO2 concentrations above wet!and surface were affected by surface qualities and land covers.     

Application of compost in agricultural practice could potentially cause contamination of foodstuffs with pathogenic bacteria such as Escherichia coli O157:H7. This study investigated pathogenic bacteria in compost collected from the compost facilities, an

IntroductionIncreasing public interests have been concerned onsafety foods and the environmental aspects recently,especially on the so-called organic foods , which are madefromcrops grown with organic fertilizers or compost but notchemical fertilizers .Pu…     

精品意识在教学过程中的实施

以教师、课程与教材、课堂、科研等要素为出发点,提出了精品意识在教学过程中的实施方法。