Pseudoelastic behavior in Y1−xPrxBa2Cu3Oy compounds

Tensile tests show that ferroelastic loops always occur at 100–150 K, 200–250 K and room temperature in the Y_1–xPr_xBa₂Cu₃O_y samples withx=0 and 0.1 for whichT _c is 92 K and 82.5 K respectively, and the shape memory effect is always observed in the compact sample near 130 K, just similar to that of thermal elastic martensitic alloys. The loss fraction (W/W) which is proportional to the area of ferroelastic loop as a function of temperature shows that there always exist static hysteresis (W/W) peaks at 130 K and 110 K which are attributed to the phaselike transition (PLT) characterized by the jump of lattice parameters. No ferroelastic loops and shape memory effect are observed in the range of 100 K to 150 K for the lowerT _c samples withx=0.3, 0.4 and 0.6.     

An Initial Inventory and Indexation of Groundwater Mega-Depletion Cases

The state of groundwater systems worldwide is presently not well defined, and in particular there is little context for agencies responsible for managing water resources to evaluate occurrences of groundwater depletion against other cases globally. In this study, an initial inventory of groundwater depletion problems is compiled and ranked to identify the world’s most critical cases, i.e. situations of groundwater mega-depletion. The ranking is based on an indexed approach that considers overdraft, drawdown and subsidence, plus the importance of the resources in terms of population-dependency and rates of extraction. The five most highly ranked depleted aquifers of the world include the shallow aquifers of the Hai River Plain (China), the Altiplano region (Spain), the Mexico Basin (Mexico), the Huang River basin (China) and the California Central Valley (USA). An abridged account of modelling to assess drawdown is described for the Hai River Plain, revealing that despite recharge in the order of 13,000 GL/yr, an overdraft of about 8,000 GL/yr is occurring to support the vast population of the region. This has led to up to 100 m of drawdown in places and reports of subsidence of several metres. The Hai River situation demonstrates that falling water levels may not act to alleviate pumping stresses; a symptom of unchecked extraction and an exemplary illustration of the tragedy of the commons. The causal factors leading to mega-depletion are varying across the globe and each mega-depletion case contains unique elements, although population appears to be an important factor.     

The optimal retrieval of ocean color constituent concentrations based on the variational method

In this paper, a new approach to the optimal retrieval of the ocean color based on the variational method is developed by setting up a rational target functional combining with the Broydor Fletcher, Goldfarb, Shanno (BFGS) optimal algorithm. The numerical tests and the exemplary retrievals are carried out and compared with the statistical retrievals and the optimal retrievals based on the genetic algorithm. The results show that this approach enjoys a higher accuracy as compared to the statistical method and a higher efficiency as compared to the genetic algorithm. The optimal retrieval method presented in this paper provides a new idea for the ocean color inversion and could also be used as a reference for the direct assimilation of the satellite data into the ecological models.     

Water and Sediment Quality in Lakes along the Middle and Lower Reaches of the Yangtze River, China

Water and sediment samples were collected from 45 lakes along the middle-lower Yangtze River, China. Each lake was sampled seasonally, over a period of one year. Water quality variables and metals in sediments were measured. Lakes along the lowest part of the river, within the Yangtze River Delta, had highest nutrient concentrations and were eutrophic or hypereutrophic. Lakes displayed a gradient in many water chemistry variables, from the middle to the lower Yangtze River. Lakes of the Delta region had the highest conductivity, sulfate, turbidity, and Chl-a values, and the lowest dissolved oxygen concentrations. A number of lakes near urban areas in the study region also displayed similar conditions. Lakes polluted by heavy metals were found in the upper part of the lower Yangtze River and had high Cu, Cr, and Co concentrations in sediments. The mean I_geo (index of geoaccumulation) values for Cu, Cr, and Co classes ranged from 0 to 4, indicating moderate to heavy contamination, contributed mainly from untreated industrial waste water produced within the lake catchments. Lakes of the middle Yangtze River are generally in relatively better condition, except for those around urban zones, which experience higher nutrient and heavy metal loading. The spatial distribution of lake conditions in the area can be related to the policy of regional economic development. The Delta region in China is developed and includes such cities as Shanghai and Suzhou. Heavy industries have moved into the interior region of China too, and development of modern cities is now occurring under some level of environmental protection. Nevertheless, lakes in the central part are becoming seriously polluted with both heavy metals and nutrients because local authorities promote industrialization and urbanization to improve economic conditions, while often ignoring environmental protection. Pollution is increasingly occurring in upstream reaches, a tendency that will bring more environmental problems. Interior lakes of China require immediate attention to prevent further declines in water quality.     

地质雷达在探测地下富含水区域中的应用

地质雷达法用于地下水探测以及地下环境监测,是近年水利和物探行业研究的热点之一.简要介绍了地质雷达法的优点及其在探测地下水活动中应用的国内外研究现状.根据雷达的频谱图和能量特征,可有效探测地下富含水区域.结合南京某小区地下管道泄漏的工程案例,对地下富含水区域和管道等其他异常情况进行地质雷达探测.实践证明地质雷达法在探测地下富含水区域方面能取得较好效果.     

“生态水文学”学科发展和研究方法概述

生态水文学作为解决现代水问题的新方式,源于解决环境问题的新思考方式——“生态工程”,以“生态水文”为主题的论文、专著、会议成蓬勃发展之势.目前研究方法概述有:①国内外多种相关监测计划的建立以及各种估算方法相结合;②流域对比、传统的宏观和基于集对原理的微观相关分析揭示机理;③多种生态水文模型与遥感技术相结合模拟生态水文过程.未来发展方向主要归纳如下:①亟待生态水文学解释与水分驱动生态系统演化相关的重大问题;②寻找生态恢复的合适尺度,通过模型尽可能描述水量平衡及水文过程;③亟待开展极端事件对气候变化和人类活动的响应研究;④加强古生态学研究,在长时间序列中识别长期生态水文演变.     

基于温度植被干旱指数的黄河源区土壤表层含水量反演

为了对黄河源区的土壤表层含水量进行反演与时空分析,利用黄河源区2006年第65—321天MODIS温度和植被指数产品数据,计算了温度植被干旱指数(TVDI),构建了不同像元尺度窗口的LST/NDVI斜率与实测表层土壤相对含水量之间的线性关系,比较了不同尺度像元窗口的拟合效果。分析结果表明:9×9像元窗口的拟合效果(回归系数R2为0.65)优于其他像元窗口尺度;季节尺度的拟合精度(回归系数R2为0.76)优于长时间序列的拟合精度;夏季模拟值与实测值的均方根误差为0.09,模拟精度满足实验要求,可用于黄河源区短时间序列的土壤表层含水量反演。     

基于区块链的分布式能源交易关键技术

分布式能源凭借能效高、运行灵活、经济性好等特点,逐渐成为发电的重要来源。区块链技术的去中心化、公开透明等特性与分布式能源的交易需求相吻合,探索基于区块链的分布式能源交易有助于消纳能源,降低信用成本。首先从双方的典型特征方面,分析了区块链技术与分布式交易的契合度;接着介绍了区块链技术在提高交易处理效率方面的新发展,以及结合了区块链技术的分布式能源交易理论研究与实际应用;然后,从点对点(P2P)交易、集合竞价以及连续双边拍卖3个方面,分析了国内外在区块链交易方面的研究现状;最后给出了中国在区块链参与消纳分布式能源、建设需求响应管理等方面的建议。     

Identification of genomic region associated with rice weevil resistance in sorghum [Sorghum bicolor (L.) Moench]

The rice weevil Sitophilus oryzae (L.) is an important pest of stored sorghum (Sorghum bicolor L. Moench). Quantitative trait loci (QTL) associated with rice weevil resistance was analyzed using a F₁₀ recombinant inbred line (RIL) population derived from the cross 654 (susceptible) × LTR108 (resistant). Grain weight losses (GWL), flour production (FP), and percentage kernels damaged (PKD) were evaluated across two trails. A total of 21 QTLs for GWL, FP, and PKD were identified. The phenotypic variation explained by individual QTL varied from 4.14% to 15.51%. Both parents contributed resistance alleles. Several main effect QTLs affecting GWL, FP, and PKD were mapped to the same regions on chromosome 2. The identification of genomic regions associated with rice weevil resistance will be useful to understand the resistance mechanism and improve rice weevil resistance of sorghum by marker-aided approaches.     

酸碱失衡与急性心血管疾病关系研究进展

急性心血管疾病作为内科常见疾病,病情进展快,病理变化复杂,常出现体内酸碱平衡紊乱,酸碱失衡尤其见于急性心肌梗死疾病中。临床研究表明,体内酸碱失衡可能会导致急性心血管系统损伤,影响疾病的预后,甚至导致心源性休克发生,因此各项酸碱监测指标对于急性心血管疾病的诊断、治疗监测和预后有着重要临床作用。