中国水足迹结构演变研究——基于国家间投入产出模型

本文基于国家间水资源投入产出模型测度1995-2009年中国33个部门直接、间接用水份额,确定了用水系数较高的部门,核算并分析分部门水足迹以及水足迹流进、流出、净水足迹及结构演变。研究结果表明,研究期间内各行业用水系数均有不同程度的降低,中国各部门大部分用水均以间接用水为主。中国水足迹总量15年间基本持平,但是水足迹结构发生了明显的变化,第一产业用水份额下降,第二、三产业份额上升。本文发现,水足迹流出占生产水足迹的很大份额,而消费水足迹则以国内生产国内消费为主。绝大多数行业均为水足迹净流出,且净流出持续增长,中国向其他国家转移了大量水资源,别国水资源得到了相应数量的节约。最后基于以上结论,提出了优化水资源配置的一些建议。

某铀矿液态流出物放射性调查及环境影响评价

对某铀矿产生的矿井水、尾矿库流出水、工艺废水等液态流出物的放射性进行调查、分析和评价,掌握液态流出物的放射性水平和受纳水体的污染情况,评价液态流出物通过各种污染途径对当地居民造成的辐射影响。结果表明,矿井水、工艺废水和尾矿库流出水经处理后,废水中的U天然、^(226)Ra、^(210)Pb和^(210)Po的排放浓度均满足限值要求;受纳水体下游河段中的U天然浓度稍高于本底水平,^(226)Ra、^(210)Pb和^(210)Po浓度均属正常本底水平。铀矿排放的液态流出物致20 km范围内居民最大个人剂量为1.45×10^(-3)mSv/a,最大集体有效剂量为2.35×10^(-4)人·Sv/a,关键居民组为WNW方位、>2~5 km区的人口组。该铀矿液态流出物在处理达标后排入受纳水体,对当地的辐射影响较小。

风之痕

这是个多么清新的初夏早晨啊,清风里弥漫着淡淡的薄荷味,阳台上肥嫩的指甲花在风中舒展筋骨,丰满得几乎透明的茎杆似乎要流出水来。莲子闭了眼深深吸口气,感觉五脏六腑都让这清凉的空气涤荡得爽爽利利。 “呀,七点半了!”莲子看看闹钟,一声惊呼,慌手慌脚收拾起来。一切就绪。

痱子防治方集锦

(1)苦瓜切开洗净,用苦瓜涂擦皮肤患处,每日3次,几日后便可见效。 (2)取熟透了的苦瓜一根,掏出部分瓜瓤,灌入中药硼砂50克,硼砂溶化后会流出水来,用这种水涂擦痱子,疗效极佳。 (3)

牛蛙维生素E缺乏症的预防

患维生素E缺乏症的牛蛙,其幼蛙、成蛙运动失调,在池水面不断打转,头向背仰,重者可后仰78—80度;有的蛙身侧弯;有的皮下水肿,以后腿多见,严重者全身水肿,切开皮肤,流出水肿液凝成胶冻样;腹腔积液;腿肌松软。蝌蚪发病生长不良,运动失调,在池水中不断打转而死亡。有的身体水肿,皮肤成蜡样,腹水增多。 预防措施 (1)牛蛙喂动物性饵料,每公斤添加维生素E100毫克就可起预防作用。(2)养殖牛蛙应提倡饲喂添加有多种维生素的颗料饲料。

注意防治小熊猫的犬瘟热

四川省某野生动物园从外地购入小熊猫16只,去年6月初发病死亡4只,病死率为25％。临床表现,眼鼻流出水样分泌物,精神不振,食欲缺乏,眼结膜潮红,眼部分泌物24小时成浓性。之后,病情加重,咳嗽、拉稀、粪便恶臭,并混有粘液或血液,病程5日左右死亡。用抗生素和磺胺药治疗无效。

味觉出汗综合征

哈尔滨市某医院曾接诊这样一位病人:一名57岁的男子,在吃饭咀嚼食物时,左侧外耳道流出水样液体。病人没有任何不舒服的感觉,也没有其他导致此病发生的原因。病人如果停止咀嚼食物,液体流出也随之停止。经医生检查。

A New Method for Effluent Treatment System Design

this paper mainly discusses the design of distributed effluenttreatment systems with single contami- nant. A new method is putforward and four basic rules are provided. The key point of themethod is that global optimality is obtained by guaranteeing theoptimality of each step taken in the design. Costs per unit mass ofremoved contaminant are used as a scale to choose the nextcombination of an effluent stream and a treatment process. Theremaining problem is updated after each choice. As for multiplecontaminants, a two-stage method is adopted.

Methodology for production logging in oil-in-water flows under low flow rate and high water-cut conditions

This study aimed to obtain the production profiles of oil-in-water flow under low flow rate and high water-cut conditions in oil wells.A combination production profile logging composed of an arc-type conductance sensor(ATCS)and a cross-correlation flow meter(CFM)with a center body is proposed and experimentally evaluated.The ATCS is designed for water holdup measurement,whereas the CFM with a center body is proposed to obtain the mixture velocity.Then,a drift-flux model based on flow patterns is established to predict the individual-phase superficial velocity of oil-in-water flows.Results show that the ATCS possesses high resolution in water holdup measurement and that flow pattern information can be deduced from its signal through nonlinear time series analysis.The CFM can enhance the correlation of upstream and downstream signals and simplify the relationship between the cross-correlation velocity and mixture velocity.On the basis of the drift-flux model,individual-phase superficial velocities can be predicted with high accuracy for different flow patterns.

一种高分辨AQP4分子磁共振成像技术有望无创预测胶质瘤治疗敏感性

2022年11月14日浙江大学白瑞良团队联合山东省立医院刘英超团队在Nature子刊《Nature Biomedical Engineering》杂志(2022年影响因子为29.234)发表了研究论文,题目为“Transmembrane water-efflux rate measured by magnetic resonance imaging as a biomarker of the expression of aquaporin-4 in gliomas”(https://www.nature.com/articles/s41551-022-00960-9)。

Wet-Dry Runoff Correlation in Western Route of South-to-North Water Diversion Project,China

The Western Route of the South-to-North Water Diversion Project is an important trans-basin diversion project to transfer water from the upstream Yangtze River and its tributaries （water-exporting area）, to the upstream of the Yellow River （water- importing area）. The long-term hydrologieal data from 14 stream gauging stations in the Western Route area and techniques including the pre-whitening approach, non-parametric test, Bayes, law, variance analysis extrapolation, and Wavelet Analysis are applied to identify the streamflow eharacteristics and trends, streamflow time series cross-correlations, wetness-dryness encountering probability, and periodicities that occurred over the last 50 years. The results show that the water-exporting area, water- importing area, and the streteh downstream of the water-exporting have synehronization in high-low flow relationship, whereas they display non- synchronization in long-term evolution. This corresponds to the complicated and variable climate of the plateau region. There is no obvious increasing or decreasing trend in runoff at any gauging station. The best hydrological eompensation probability for rivers where water is diverted is about 25% to lO%, and those rivers influenced significantly by diversion are the Jinsha and Yalong rivers. Proper planning and design of compensation reservoirs for the water-exporting area and stretch downstream of the water- exporting area can increase the hydrological compensation possibility from water-exporting area to the water-importing area, and reduce the impact on the stretch of river downstream of the water- exporting area.

Parametric Optimization of Organic Rankine Cycle with R245fa/R601a as Working Fluid

In order to select the appropriate working fluids and optimize parameters for medium-temperature geothermally-powered organic Rankine cycle(ORC), R245 fa is mixed with R601 a at geothermal water temperature of 110 ℃. Based on thermodynamics, the characteristics of mixture and its influence on the performance of ORC under different evaporating temperatures and composition proportions are analyzed. Results show that the zeotropic mixture R245fa/R601a(0.4/0.6) has the highest performance. When the evaporating temperature reaches 67 ℃, the outlet temperature of geothermal water is 61 ℃, the net power output is the highest and the thermal efficiency is about 9%.

机械钟表的漫长前夜

在人类仅仅依靠种植和放牧来维持生计的昨天,时间的小单位计算在生产生活中并不那么重要,对于当时的人类而言,最要紧的是掌握每年的节气,知道什么时候下雨下雪、耕种收割,比掌握煮熟一个鸡蛋需要多少时间更为迫切,精确计算时间的意义只有那些统治者和达官贵人才有可能意识得到。

Unsteady heat-moisture transfer of wet airway in deep mining

To study the mechanism of unsteady heat-moisture transfer of wet surrounding rock in deep mining, a series of experiments with different initial and boundary conditions were carried out. Test results show that rock temperature decreases quickly at the initial stage, and reduces slowly to be a constant value finally for transient heat-moisture transfer. The quasi-steady surface temperature of wet airway is lower than that of dry airway due to the moisture transfer. The diffusion radius is less than the cooling radius owing to the large diffusion resistance. The outlet airflow enthalpy of wet airway is much larger than that of dry airway. Latent heat caused by the moisture transfer plays a significant role in a deep thermal environment. For periodic heat-moisture transfer, temperature, humidity and enthalpy of outlet airflow and rock temperature also change periodically. The wave amplitude of rock temperature decreases gradually with increasing distance away from the airway surface, and the wave phase of rock temperature is also behind that of airflow. Moreover, direction of the heat-moisture transfer between airway and airflow is bidirectional, which is different from results of transient transfer.

Dynamic characteristics of the high-flow water three-way valve

Operating principle of water three-way valve with high flow for individual hydraulic prop in coal was presented in this paper, its strict and precise mathematical model was established, its flow field was simulated numerically by software Fluent, and its dynamic characteristics were analyzed during the work process such as raising leg, loading and overflow, the influence of the related parameters on high-flow water three-way valve was determined. The results as follows： during the raising leg stage and early raising leg stage, when the damping ratio increases, the overshoot of system decreases and the setting time reduces, and the dynamic response performance has a significant improvement. During the loading stage and the overflow stage, the pressure in plunger chamber of single hydraulic prop, the output flow and the displacement of the high-flow water three-way valve decrease with the decreasing of the external load. The spring stiffness of the safety valve directs the flow and the spool＇s displacement of the safety valve, and it can be used to control the high-flow three-way valve＇s sensitivity.

Effects of Clearance between Rotor and Ground on the Performance of an Open Cross-Flow-Type Nano-Hydraulic Turbine

Flows through an open cross-flow-type nano-hydraulic turbine are numerically simulated to investigate the effects of the clearance Hc between the rotor and the ground on the turbine performance. A two-dimensional particle method is employed, which was successfully used for flow simulations of impulse-type and open cross-flow-type nano-hydraulic turbines in the authors＇ previous works. When the clearance Hc is smaller than a critical value, the simulated turbine performance decreases with decreasing Hc, in good agreement with the experiment. The simulations make it clear that such a reduction of turbine performance is attributable to an increase in the circumferential component of the water velocity at the rotor outlet. The simulations also demonstrate that the effect of the tip speed ratio of the rotor on the relation between Hc and turbine performance can be analyzed.

糠饼钩钓大青

今年4月16日，湘北下着大雨，但没有动摇我外出垂钓的决心。我和9位约友凌晨4时30分乘车，于6时40分左右到达岳阳境内的铁山水库垂钓。7时许我在一湾里选好钓位，打好窝子钓鲫鱼，随后又将一到自制的糠饼钩投入高岸二十多米的水中。据当地人后来讲，那里原来是个大池塘。?..

保管化肥“六注意”

保管化肥“六注意”１注意防潮：化肥购进之后一定要置于干燥不返潮的仓库里。因化肥极易溶解于水，所以如把化肥置放于地势低洼的仓库里，就会使化肥化掉、流出水，大大降低肥效。２．注意防火：硝酸钦、硝酸钾在高温下易分解，并放出大量气体，若猛烈撞击会产生爆炸。因...

Working fluid selection based on critical temperature and water temperature in organic Rankine cycle

This paper examines the thermal performance of working fluids in the entire evaporation temperature region up to near-critical temperature of working fluids in the organic Rankine cycle(ORC).The variation and tendency of the net power output with water temperature and correlated with the critical temperature of working fluids is investigated.Four characteristic curves of the net power output at particular water temperature(Tw_turn,Tw_app,Tw_tran and Tw_up)and their temperature difference(△T_turn=Tw_turn△Tcr,△T_app=Tw_app△Tcr)are obtained to evaluate the working fluids.The curve at"applicable water temperature(Tw_app)"is a demarcation to differentiate the net power output from low to high.The"upper water temperature(Tw_up)"is an upper limit of the water temperature to yield the higher net power output.A relation is built that the suitable water temperature is within the Tw_app and Tw_up of the working fluid.

Contribution of baseflow nitrate export to non-point source pollution

As a common pollutant of nitrogen in groundwater, nitrate contamination has become a major concern worldwide. Baseflow, one of the dominant hydrological pathways for nitrate migration to streamflow, has been confirmed as a leading nitrate source for stream water where groundwater or subsurface flow contaminated heavily by nitrate. That is, sufficient improvements of water quality may not be attained without proper management for baseflow, even if non-point sources(NPS) pollutants discharged through surface runoff are being well managed. This article reviews the primary nitrate sources, the main factors affecting its transport, and the methodologies for baseflow nitrate estimation, to give some recommendations for future works, including:(1) giving sufficient consideration for the effects of climatological, morphological, and geological factors on baseflow recessions to obtain more reliable and accurate baseflow separation;(2) trying to solve calibration and validation problems for baseflow loads determining in storm flow period;(3) developing a simple and convenient algorithm with certain physics that can be used to separate baseflow NPS pollution from the total directly in different regions, for a reliable estimation of baseflow NPS pollution at larger scale(e.g., national scale);(4) improving groundwater quality simulation module of existing NPS pollution models to have a better simulation for biogeochemical processes in shallow aquifers;(5) taking integrated measures of "source control", "process interception" and "end remediation" to prevent and control NPS nitrate pollution effectively, not just only the strict control of nutrients loss from surface runoff.