膨胀土干湿循环胀缩裂隙演化的CT试验研究

对南阳重塑膨胀土在干湿循环过程中裂隙的演化进行了CT试验研究，试样的CT图像显示了原有裂隙开展，新裂隙产生，裂缝数量增加并连通，最后形成裂隙网络的过程。定义了基于CT数据的裂隙损伤变量，分析了裂隙损伤变量随累计干缩体变的变化规律。     

深海鲣鱼(Katsuwonus pelamis)低温热泵联合干燥技术优化及品质分析

为了提高深海鲣鱼(Katsuwonus pelamis)干制品的质量,采用低温热泵联合干燥技术,对深海鲣鱼干制品的色差值、复水比、细菌总数、T-VBN值以及能耗值等指标进行分析测定。实验结果表明,低温热泵联合干燥技术较传统单一干燥技术在干燥效果、干燥能耗以及投入设备成本等方面更具有优势。进一步对影响低温热泵干燥技术的因素主要包括填物料量、循环风速、干燥室温度和相对湿度等进行优化。研究结果表明:深海鲣鱼(500g左右)在干燥室相对湿度控制35%、干燥室温度为45°C、装填物料量为8kg、循环风速为2.5m/s时候干燥效果最佳,并且节能效果明显,能耗降低达到35.2%。该成果的成功开发对降低水产品干燥过程中的耗能问题具有促进作用。     

Modeling the impacts of drying trend scenarios on land systems in northern China using an integrated SD and CA model

Climate-induced drought has exerted obvious impacts on land systems in northern China. Although recent reports by the Intergovernmental Panel on Climate Change (IPCC) have suggested a high possibility of climate-induced drought in northern China, the potential impacts of such drying trends on land systems are still unclear. Land use models are powerful tools for assessing the impacts of future climate change. In this study, we first developed a land use scenario dynamic model (iLUSD) by integrating system dynamics and cellular automata. Then, we designed three drying trend scenarios (reversed drying trend, gradual drying trend, and acceleration of drying trend) for the next 25 years based on the IPCC emission scenarios and considering regional climatic predictions in northern China. Finally, the impacts of drying trend scenarios on the land system were simulated and compared. An accuracy assessment with historic data covering 2000 to 2005 indicated that the developed model is competent and reliable for understanding complex changes in the land use system. The results showed that water resources varied from 441.64 to 330.71 billion m³ among different drying trend scenarios, suggesting that future drying trends will have a significant influence on water resource and socioeconomic development. Under the pressures of climate change, water scarcity, and socioeconomic development, the ecotone (i.e., transition zone between cropping area and nomadic area) in northern China will become increasingly vulnerable and hotspots for land-use change. Urban land and grassland would have the most prominent response to the drying trends. Urban land will expand around major metropolitan areas and the conflict between urban and cultivated land will become more severe. The results also show that previous ecological control measures adopted by the government in these areas will play an important role in rehabilitating the environment. In order to achieve a sustainable development in northern China, issues need to be addressed such as how to arrange land use structure and patterns rationally, and how to adapt to the pressures of climate change and socioeconomic development together.     

Selected aspects of studies of sediments from the Ebro River （Spain） and the Dobczyce drinking water reservoir （Poland） within the frames of the European and national research projects

Mineral and organic matter either soluble or suspended are transported by the rivers and when deposited in the bed of the river or in the water reservoir, sediments are formed, whose chemical composition may serve as a fingerprint of the history of the ecosystem. The results of the studies of sediments in water systems （river catchments, reservoirs） can be used not only for the evaluation of the current state of the ecosystem but also to prevent any dangerous environmental changes. Bottom sediments can in many ways accumulate both suspended and soluble components. The process is influenced by several factors like pH, red-ox potential, oxygen content, interactions, etc. The complexity of those phenomena causes that in order to study the accumulation processes of compounds in sediments the application of various analytical techniques is required. The authors participate in two big projects on sediment studies. The AquaTerra Project is the EU funded project on understanding river-sediment-soil-groundwater interactions for support of management of river basins and catchment areas. Our group＇s studies are focused on mercury determination and its speciation in sediments and fish from the Ebro River in Spain. The Dobczyce Project is the national project funded by the Ministry of Education and sciences of Poland which is also a EU member country. The latter covers many aspects of accumulation and fate processes of chemical compounds in sediments of the reservoir which supplies 60% of drinking water to about one million population in the city of Krakow in Poland.     

深圳湾海域环境容量及污染总量控制研究——I.潮汐、潮流数值模拟

基于美国普林斯顿大学的POM(Princeton Ocean Model)模型,将干湿网格技术引入到模型中,利用模型的外模式(二维)对深圳湾海域的潮汐、潮流和余流进行了数值模拟研究。模拟结果与实测值吻合较好。计算结果表明:深圳湾海域属不正规半日潮,水平潮流具有明显的往复流性质,主要呈西南—东北走向;落潮流速略大于涨潮流速;受地形及陆地河流径流的影响,湾中到湾口及航道附近流速较大,湾顶和靠近香港的滩涂部分流速较小;深圳湾余流场较弱,余流流向指向湾外;整个深圳湾水交换较弱,海域自净能力较差。     

BOM的动边界改进及其应用

针对河口海岸数值模拟的动边界问题,使用了一个简便的干湿网格法,对BOM(Burgen Ocean Model)模型进行了动边界改进。并将该模型应用于瓯江口海域进行数值模拟计算,计算结果表明实测值与计算值吻合良好,模型能够较好的模拟岸边界随潮位涨落的变动。     

重组鲑鱼降钙素结肠黏附缓释微球的制备

为考察重组(酵母)鲑鱼降钙素结肠黏附缓释微球的制备工艺和最优处方,并对释药特性进行探讨。以阿拉伯胶、β-环糊精、可溶性淀粉、明胶为壁材,HPMC和卡波姆为生物黏附剂,运用正交试验确定喷雾干燥法制备微球的最佳工艺条件和处方。结果表明,微球的最佳制备工艺和处方为β-环糊精与阿拉伯胶以15∶1、HPMC与CP以4∶1配比为理想壁材,喷雾干燥进风温度160℃、进料速度10mL·min-1、雾化压力0.5MPa、壁材浓度15%、芯材比1∶3为最佳组合,所得微球能达到缓释12h的试验设计要求。本法工艺稳定、可行,所得鲑鱼降钙素结肠黏附缓释微球具有良好的缓释效果。     

Water storage capacity of empty fruiting heads of Liquidambar styraciflua L. (sweetgum) / Capacité de stockage d’eau des bourgeons fruitiers vides de Liquidambar styraciflua L. (le copalme d’Amérique)

Abstract

Abstract The water storage capacity (WSC) of dehiscent fruits that constitute a portion of litter on the forest floor is inadequately understood. This study has quantified the WSC of empty fruiting heads of sweetgum (Liquidambar styraciflua L.) in an effort to reduce the data gap on the WSC and interception of fruit litter. In a laboratory experiment, empty fruiting heads of sweetgum were found to have a mean WSC of 399% of their oven-dried weight. The maximum volume of water detained by fruiting heads in the field was 507 ml container^-1. Interception by the empty fruiting heads is considerable, ranging from 2.6 to 218.5% of the incident gross precipitation, with a mean of 42.7%. The data indicate that the interception storage capacity of empty fruiting heads is reached at 2.5 cm depth equivalent of incident gross precipitation. A logarithmic relationship was observed between the volume of water detained by the fruiting heads and the length of time since precipitation. Results of the study suggest that fruit litter may have a considerable influence on the seasonal water balance and ecohydrology of plantations and forests with significant proportions of sweetgum.     

Effect of swelling inhibitors on the swelling and stress relaxation of clay bearing stones

Clay-containing stones such as Portland Brownstone (USA), Villarlod Molasse (Switzerland) and Tarifa Sandstone (Spain), are expected to weather as a result of wetting and drying cycles. During drying events, contraction of the drying surface leads to stresses approaching the tensile strength of the stone. However, we have found that the magnitude of these stresses is reduced by the ability of the stone to undergo stress relaxation. In this paper we describe novel methods to determine the magnitude of the stresses and the rate at which they develop and relax. We also discuss the influence of swelling inhibitors on the magnitude of swelling and the rate of the stress relaxation of these stones. The implications of our findings for the understanding of damage due to swelling of clays are discussed.Special Issue: Stone decay hazards