基于流体力学的湿帘风机温室内气流运动的模拟分析（英）

湿帘风机冷却系统温室内的气流运动和微环境特征的研究对整个冷却系统的冷却效率及温室环境调控方案的确立有着重要的指导意义,该研究通过流体力学商用软件有限元法对温室内横断面的温度,气流,湿度分布进行仿真计算,在温室模型中考虑到作物群体对气流的阻碍作用,将作物群体作为多孔介质进行模型化处理,分析湿帘风机冷却系统不同的工作条件下即（1风机工作,2风机湿帘共同工作）,温室内微环境的时空变化规律,通过实测数据进行验证计算结果表明,气流速度的误差在2.1%到18.3%, 温度误差范围较小在0.1%到2.6%,湿度误差在2.0到12.64%。     

Fluxes and storage of fine-grained sediment and associated contaminants in the Na Borges River (Mallorca,Spain)

Samples of suspended and fine channel bed sediment were used to examine the spatial and temporal variability in the amount of fine-grained sediment and associated contaminants temporarily stored in the Na Borges River (319 km²) in Mallorca and the relationship of such channel storage to the fluxes of fine sediment and associated contaminant through the system. This Mediterranean groundwater-dominated river drains a predominantly agricultural catchment, although urbanisation during the twentieth century has changed the catchment hydrology. A re-suspension technique was used to obtain estimates of channel storage at monthly intervals during the 2004–2005 hydrological year at eight locations along the main stem of the stream (i.e. 26 km). The estimates of fine sediment storage ranged between 0 and 13,000 g m^− 2, with a mean value of 2400 g m^− 2. Only Cu exceeded the critical threshold (36 μg g^− 1), established by existing guidelines for the contaminant content of fluvial sediment. The results demonstrated significant spatial and temporal variability, in response to the influence of urban point sources, agricultural practises, seasonal groundwater interactions and the first-flush effect. The amount of fine sediment entering storage during the study period was 515.2 t, representing the net increase in storage over the study period. As a result, the mean specific storage was 21 t km^− 1. Suspended-sediment load and temporary fine sediment storage are the two basic components of the channel sediment budget that interact to determine sediment transport through a channel system, and they can therefore be used to compute the total input of sediment and associated contaminants to the system. Accordingly, storage values were compared with estimates of suspended sediment load and associated contaminant load values at three measuring stations along the river. During the study period, storage in the main channel system represented 87% of the sediment input and 68% of the contaminant input, indicating that deposition was more important than transport. The low gradient of the main channel and the low return period (i.e. 0–2.5 years) of the flood events that occurred during the study period meant that remobilised bed sediment and associated contaminants were redeposited downstream rather than being flushed to the catchment outlet as suspended sediment. Furthermore, the river bed is dry during the summer months, allowing sealing and crusting processes to stabilise the sediment deposited during the wet season and thereby reduce its availability for remobilisation at the beginning of the next wet season. Together, these factors promote sediment deposition and storage, with the result that sediment progressively accumulate over several hydrological years until a major flood event (i.e. return period ≈ 5 years) evacuates the stored sediment.     

白龙江中游泥石流冲积扇坡耕地开发潜力分析

泥石流冲积扇是山区难能可贵的相对平坦土地资源,对其进行开发利用对山区农业经济的发展具有重要意义。以白龙江中游泥石流冲积扇坡耕地为研究对象,通过野外考察,结合室内Quick Bird 10m分辨率卫星影像解译,选取冲积扇面积、灌溉水源、泥石流频率、防治措施、已开发比例5个评价因子,对白龙江中游泥石流冲积扇坡耕地的分布、开发利用现状、开发潜力进行了分析和评价。结果表明:一是白龙江中游172个泥石流冲积扇总面积约为30.0km2,占河谷平坦地面积的52.07%;二是泥石流冲积扇在白龙江干热河谷所占的面积相当大,开发潜力高的泥石流冲积扇坡耕地有90个,占总数的52.3%。由此可见,整个白龙江中游区泥石流冲积扇具有很好的开发潜力,其中以沙湾-固水子段的开发潜力最高。     

泥石流扇形地土地整治与利用

泥石流扇形地是山区宝贵的土地资源,但其土壤层次结构不合理,物理结构性差,养分贫瘠,有机质含量均不足1%,有效氮、有效磷及有效钾含量水平中等偏低.针对扇形地本身的地形、土质、养分等特点和开发利用中出现的问题,提出了泥石流扇形地改造利用的整地措施、改土措施和培肥措施.通过引浑停淤改良,土壤颗粒主要分布在0.02～0.002mm之间,土壤质地由壤质砂土改良为粉质黏壤土;土壤表土层厚度增加7 cm,达到25 cm;土壤微团聚体数量为95.31%,比未改造泥石流荒滩地提高了56.87%,改良后的微团聚体主要分布在0.02～0.002 mm之间,对增强土壤保肥蓄水功能具有重要作用.经过改造后的扇形地具有很高的生产潜力,其自然生产潜力可达3万2 586 ks/hm2;而泥石流荒滩地、非引浑改良泥石流滩地土壤的自然生产潜力分别仅为1万9 295和2万8 299 kg/hm2.在不同类型的泥石流扇形地中,黏性泥石流形成的扇形地细颗粒含量较多,容易改造成优质高产农田;稀性泥石流的扇形地细颗粒含量相对较少,改造的难度大,成本高.在不同开发程度泥石流扇形地中,新开垦的泥石流扇形地(砾石含量高),宜种植水果、西瓜、红薯、花生等;经长期改造土壤质地和肥力都得到明显改善的扇形地,可种植水稻和反季节蔬菜等高效益的有机粮品和绿色粮品;而对于难以改造的稀性泥石流扇形地,可以经过简单整地,发展西瓜、石榴等对土壤质地要求不高的作物.     

北京双紧梢沟泥石流堆积物的特征及演变

北京山区具备泥石流形成与发生条件,泥石流灾害的发生较为频繁。在收集当地泥石流发生历史资料的基础上,详细调查了西白莲峪双紧梢沟的自然地理状况和泥石流堆积物的特点。采用野外量测和填图的方法调查双紧梢沟泥石流的地貌特征;现场选取一定数量的砾石进行abc长度和倾向调查,测定双紧梢沟泥石流堆积物的结构特征;选定泥石流典型区域,进行挖圆探坑,取出全部颗粒并带回实验室,进行粒度分析;同时,对双紧梢梢沟泥石流堆积扇的发育和演变过程进行分析。粒度分析结果表明双紧梢沟泥石流堆积物砾石平均粒径为0.256m,磨圆度为2～6。90%以上砾石直径为0.220～0.410m,最大砾石直径为0.409m,堆积物主要有砾石和一些粗骨性碎屑物质组成,砾石排列无明显特征,分选差。由粒度分析可知,该区泥石流堆积扇的形成受到水石流形成过程的影响,水石流形成堆积扇,之后可能发生粘性泥石流。由其频率曲线为一多峰曲线。该曲线说明泥石流发生时,其砾石的搬运方式由推移、跳跃、悬浮三大部分组成。双紧梢沟泥石流堆积扇的演变过程和特征明显受到双紧梢沟和西白莲峪主沟水流的影响。该研究结果对今后进一步探讨北京山区泥石流形成机理和运动过程以及为泥石流防治制定有效措施提供参考。     

Carbon stocks of soil and vegetation on Danubian floodplains

Riparian forests are assumed to play a crucial role in the global carbon cycle. However, little data are available on C stocks of floodplains in comparison to other terrestrial ecosystems. In this study, we quantified the C stocks of aboveground biomass and soils of riparian vegetation types at 76 sampling sites in the Donau‐Auen National Park in Austria. Based on our results and a remotely sensed vegetation map, we estimated total C stocks. Carbon stocks in soils (up to 354 t ha^–1 within 1 m below surface) were huge compared to other terrestrial ecosystems. As expected, soils of different vegetation types showed different texture with a higher percentage of sandy soils at the softwood sites, while loamy soils prevailed at hardwood sites. Total C stocks of vegetation types were significantly different, but reflect differences in woody plant biomass rather than in soil C stocks. Mature hardwood and cottonwood forests proved to have significantly higher total C stocks (474 and 403 t ha^–1, respectively) than young reforestations (217 t ha^–1) and meadows (212 t ha^–1). The C pools of softwood forests (356 t ha^–1) ranged between those of hardwood/cottonwood forests and of reforestations/meadows. Our study proves the relevance of floodplains as possible C sinks, which should be increasingly taken into account for river management. Furthermore, we conclude that plant‐species distribution does not indicate the conditions of sedimentation and soil C sequestration over the time span of interest for the development of soil C stocks.     

Cavern type airflow control technology of mine

Taking a coconut shell powder activated carbon (PAC) as the carrier and butyl acetate titanate with ethanol as raw materials, TiO2/AC(activated carbon) photocatalyst was prepared through sol-gel and impregnation method, and batch experiments were carried out to investigate its performances of removing Carbamazepine from artificial water. The results indicate that TiO2/AC has a better removal of carbamazepine than powder TiO2 and PAC. In the same condition, the removal of carbamazepine in TiO2/AC system is 1.7 times than that in TiO2. When the initial concentration of Carbamazepine is 10 mg/L, and the dosage of TiO2/AC is 500 mg/L, in which the load capacity of TiO2 is 11.2%, the removal rate reaches at 91.5% while the PH is 1.0. The reaction of photocatalytic degradation process can be accorded with two-step dynamics kinetics with different concentrations. The constant of secondary reaction is inversely proportional to concentration. Using Langmuir-Hinshelwood (L-H) model, it concludes that the apparent adsorption equilibrium constant Ka is 9.215×10 3 L/mol, and the surface reaction rate constant Kr is 3.678×10 -6 mol/(L·min). Thus, microwave irradiation is the best way for catalyst regeneration.     

排管库在香梨贮藏中的优化设计及其优势分析

根据库尔勒香梨的贮藏特性,优化排管库的设计,并针对排管库的使用及运行管理中存在的问题提出解决的办法。同时,通过在排管库和风机库内贮藏香梨效果的对比试验,对两种类型的冷库进行优势分析。结果表明,按香梨在相同库容的排管库和风机库内贮藏8个月计算,优化的排管库可比风机库节电约33%,香梨果实失重率显著降低(P0.05),保鲜效果良好,优势明显。     

预酸化对云南乳扇凝乳的影响

本研究利用热处理的酸乳清对牛乳进行预酸化处理,研究酸乳清对乳扇凝乳效果的影响,根据热烫拉伸工艺的需要,控制凝乳的pH值,分析不同的温度和pH值对凝乳效果的影响。结果表明:凝乳温度34℃、凝乳pH值5.2时,酪蛋白流失最少,凝乳效果最好。乳扇加工工艺中通过酸乳清对牛乳进行预酸化处理,可以解决凝乳过程中凝块pH值不固定的问题。     

新型气力供料器的研究

根据目前市场上对供料装置的特殊需求,设计出了一种新型的供料装置。新设计开发的供料器采用风机分流的气力侧面进给,吹动供料器叶片,使物料顺利落下。该供料器增强了密封性能,清洁方便,满足使用性能。其特点是：减少了一套驱动叶片旋转的传动装置,利用较为简单的结构形式,实现供料器的供料;并且体积小、重量轻、结构紧凑、制造容易、装调方便。