农业旱灾监测中土壤水分遥感反演研究进展

土壤水分是农业干旱监测最重要的指标之一。文章全面回顾了光学遥感和微波遥感土壤水分遥感反演进展，重点讨论了符种反演方法的优点和不足。光学遥感中，热惯量法和作物缺水指数法可分别较好地应用于裸露地和作物覆盖地的土壤水分监测；距平植被指数、植被条件指数采用了植被指数因子实现农业旱情监测，温度植被指数、植被供水指数和条件植被温度指数同时考虑了作物植被指数和地表温度。微波遥感被认为是当前土壤水分监测中最有效的方法。主动微波遥感空间分辨率较高，但对土壤粗糙度和植被敏感；被动微波遥感空间分辨率低，重访周期短，对大尺度农业旱灾监测具有较大潜力。为提高农业旱灾监测巾土壤水分遥感反演的精度和效率，采用光学遥感和微波遥感的结合可能是较为实际的方法。     

Recycling-oriented characterization of plastic frames and printed circuit boards from mobile phones by electronic and chemical imaging

This study characterizes the composition of plastic frames and printed circuit boards from end-of-life mobile phones. This knowledge may help define an optimal processing strategy for using these items as potential raw materials. Correct handling of such a waste is essential for its further “sustainable” recovery, especially to maximize the extraction of base, rare and precious metals, minimizing the environmental impact of the entire process chain. A combination of electronic and chemical imaging techniques was thus examined, applied and critically evaluated in order to optimize the processing, through the identification and the topological assessment of the materials of interest and their quantitative distribution. To reach this goal, end-of-life mobile phone derived wastes have been systematically characterized adopting both “traditional” (e.g. scanning electronic microscopy combined with microanalysis and Raman spectroscopy) and innovative (e.g. hyperspectral imaging in short wave infrared field) techniques, with reference to frames and printed circuit boards. Results showed as the combination of both the approaches (i.e. traditional and classical) could dramatically improve recycling strategies set up, as well as final products recovery.     

Research on the evolvement of morphology of coking coal during the coking process

The evolvement of morphology and structure of the coal with different metamorphic degrees during coking process in the vertical furnace was investigated by infrared Image detector. Moreover, the temperature distribution in the radial direction and the crack formation were also studied in heating process. The results show that the amount of crack and the shrinkage level of char decrease with the coal rank rising. In addition, the initial temperature of crack formation for char increases with the coal rank rising.     

锚索拉断火花引爆瓦斯的实验研究

设计了锚索拉断火花引爆瓦斯实验装置 ,在瓦斯浓度为爆炸范围的环境中 ,对锚索拉断时产生火花规律及引起瓦斯爆炸的可能性进行了一系列实验研究。结果表明 :锚索拉断产生火花的概率为 5 0 % ,锚索钢绞线破断产生的火花不能引起瓦斯爆炸。采用红外热成象仪对锚索拉断火花温度的测试表明 ,锚索拉断产生的火花最高温度远小于瓦斯爆炸所需的最低点燃温度 6 5 0℃。     

Evaluation of groundwater and soil pollution in a landfill area using electrical resistivity imaging survey

Landfills are sources of groundwater and soil pollution due to the production of leachate and its migration through refuse. This study was conducted in order to determine the extent of groundwater and soil pollution within and around the landfill of Seri Petaling located in the State of Selangor, Malaysia. The condition of nearby surface water was also determined. An electrical resistivity imaging survey was used to investigate the leachate production within the landfill. Groundwater geochemistry was carried out and chemical analysis of water samples was conducted upstream and downstream of the landfill. Surface water was also analyzed in order to determine its quality. Soil chemical analysis was performed on soil samples taken from different locations within and around the landfill in the vadose zone (unsaturated zone) and below the water table (in the soil saturated zone). The resistivity image along line L–L₁ indicated the presence of large zones of decomposed waste bodies saturated with highly conducting leachate. Analysis of trace elements indicated their presence in very low concentrations and did not reflect any sign of heavy metal pollution of ground and surface water or of soil. Major ions represented by Na, K, and Cl were found in anomalous concentrations in the groundwater of the downstream bore hole, where they are 99.1%, 99.2%, and 99.4%, respectively, higher compared to the upstream bore hole. Electrical conductivity (EC) was also found in anomalous concentration downstream. Ca and Mg ions represent the water hardness (which is comparatively high downstream). There is a general trend of pollution towards the downstream area. Sulfates (SO₄) and nitrates (NO₃) are found in the area in low concentrations, even below the WHO standards for drinking water, but are significantly higher in the surface water compared to the groundwater. Phosphate (PO₄) and nitrite (NO₂), although present in low levels, are significantly higher at the downstream. There is no significant difference in the amount of fluoride (F) in the different locations. In the soil vadose zone, heavy metals were found to be in their typical normal ranges and within the background concentrations. Soil exchangeable bases were significantly higher in the soil saturated zone compared to the vadose zone, and no significant difference was obtained in the levels of inorganic pollutants. With the exception of Cd, the concentration ranges of all trace elements (Cu, Zn, Cr, Pb, and Ni) of Seri Petaling landfill soils were below the upper limits of baseline concentrations published from different sources.     

Current status of prenatal diagnosis,operative management and outcome of esophageal atresia/tracheo-esophageal fistula

Ultrasonographic features suggestive of esophageal atresia with or without tracheo-esophageal fistula (EA/TEF) are only in a small minority of fetuses with EA/TEF (<10%) identifiable on prenatal scans. The prenatal diagnosis of EA/TEF relies in principle, on two nonspecific signs: polyhydramnios and absent or small stomach bubble. Polyhydramnios is associated with a wide range of fetal abnormalities, but most commonly it pursues a benign course. Similarly the sonographic absence of a stomach bubble may point to a variety of fetal anomalies. The combination of polyhydramnios and absent stomach bubble in two small series offers a modest positive predictive value of 44 and 56% respectively. Prenatal scanning for EA/TEF identifies a larger proportion of fetuses with Edwards syndrome; there is also a higher proportion of isolated EA in comparison to postnatal studies. Current ultrasound technology does not allow for a definite diagnosis of EA/TEF and therefore, counseling of parents should be guarded. Postnatal diagnosis of EA is confirmed by the failure to pass a firm nasogastric tube into the stomach; on chest X-ray, the tube is seen curling in the upper esophageal pouch. Corrective surgery for EA/TEF is well established and survival rates of over 90% can be expected. Copyright © 2008 John Wiley & Sons, Ltd.     

The history of the second-trimester sonographic markers for detecting fetal Down syndrome,and their current role in obstetric practice

This review summarizes the development, history and use of second-trimester sonographic markers for the detection of fetal Down syndrome over three decades. Starting with the nuchal fold thickening in 1985 and culminating in the genetic sonogram in the 1990s. The combination of second-trimester serum screening with the ultrasound markers improved the detection rate of affected fetuses but also allowed patients to decrease their risk of carrying a fetus with Down syndrome if the genetic sonogram was normal. More recently the role of the genetic sonogram and its markers have changed with the wide spread use of first-trimester screening. This prior screening ultimately decreases the prevalence of fetal Down syndrome in the second trimester to less than 85% of what it was in the first-trimester as most fetuses with Down syndrome are now identified early. Current interpretation of the second-trimester Down syndrome markers must be based on the result of the first trimester and combined screening to achieve the most accurate risk estimate of an affected fetus. Copyright © 2010 John Wiley & Sons, Ltd.