煤层定点水力压裂防冲的机制研究

为实现在掘进或回采前对冲击危险煤层的一次性卸压,达到区域防冲的目的,提出了煤层定点水力压裂技术。为了从理论上说明煤层定点水力压裂技术防治冲击地压的可行性和有效性,首先,通过建立煤层压裂力学模型,从定性和定量两方面分析煤层定点水力压裂防冲的机制,认为煤层压裂通过增阻和降能2方面实现冲击地压的防治;提出了基于压裂效能指数In的压裂防冲效果评价方法以及关键冲击块临界体积的估算公式,为煤层压裂施工参数的选择提供参考;最后,在华丰煤矿1412工作面成功应用该项技术,从现场观测、管路压力、微震事件和应力变化4方面验证了煤层定点水力压裂技术防治冲击地压的效果。

河道形态改造对城市河流生态水力性能的影响

为探究城市河道形态改造的有效性,根据河道自然修复理念,采用正弦函数对典型城市渠化河道的河宽、水深和蜿蜒度等地形几何变量进行振荡波动,并借助数字河道合成技术生成6种河道数字地形模型,在此基础上采用二维水动力模型考察不同河道形态改造对河床干扰度、水力形态多样性指数和浅滩缓流生境面积等生态水力指标的影响。结果表明:研究河段城市渠化河道生态水力性能随地形几何变量的振荡波动而变化,且河道空间形态越复杂,河道生态水力性能越好;在高流量(8~12 m 3/s)下,“深潭浅滩”形态构造下河床干扰度平均减少88.2%,水力形态多样性指数平均提高37.4%,而浅滩缓流生境面积增加24.9倍,表明河流生态水力性能得到显著改善;城市河道近自然形态重构能大幅降低河道对于流量变化的敏感性,并显著提高河道生态结构稳定性,有助于河流生态系统的恢复。

明渠水面曲线的简化计算

工程中一般采用分段法进行明渠水面曲线的计算 .应用分段法时 ,需要计算每个流段的平均水力坡度 ,由于平均水力坡度的计算十分繁琐 ,计算工作量大 .本文采用一种简化法计算明渠水面曲线 ,不必计算平均水力坡度 ,可使计算工作量大为减少 .即用渠道的正常水深与流段的平均水深之比的x次方之值来代替平均水力坡度 .通过算例证明 ,采用简化法计算结果与分段法比较 ,其误差不到 1% 。

棱柱体明渠水面曲线的级数解法

根据水利工程的实际应用和所需的精度要求,结合水力学所涉及的各类不同因素及水流运动变化特点,为寻求各型水面曲线的简捷计算方法,在此引用级数的概念,研究棱柱体明渠恒定渐变流水面曲线的解,通过对已建成的十几个中小型水利工程实例和在教学实践中、结合实际工程设计进行水面曲线简化计算的研究后,认为棱柱体明渠水面曲线级数解是适宜于中小型水利工程精度要求、且计算方法简便快捷求解水面曲线解的又一种途径。

应用水力性能指数法制定排水管网达标改造方案

采用水力性能指数表征排水管网的服务性能,有助于提高排水管网诊断的准确性以及改造工程的费用效益。以合肥市老城区某排水系统为研究对象,依靠管网水力模型提供计算手段,采用水力性能指数评价法详细考察了管段自身设计输水能力的不足和下游壅水作用对超载的贡献比例,确定了达标改造的重点管段。结果表明,翻排占系统总管长13.7%的管段,可使原有未达到规划标准的系统安全排放一年一遇的降雨产生的径流;与主要根据水头损失评价瓶颈管段的方法相比,优化方案可有效减少旧系统达标改造的工程量。

变荷载下考虑非达西渗流的一维固结半解析解

基于非达西渗流定律,运用成层地基线性固结解析解与数值离散相结合的半解析方法,得到变荷载作用下一维固结问题的半解析解。将半解析解与达西渗流下的解析解和非达西渗流下的差分解进行对比,验证半解析解的可靠性。进而对不同参数下的固结性状进行分析。结果表明:非达西渗流模型中的参数对一维固结性状有重要影响,指数越大、临界水力坡降越大,则土层的固结速率越慢;同时,荷载的大小与土层厚度对土层固结性状有重要影响,作用于土层的荷载越大,则固结速率越快;土层越厚,则固结速率越慢。在非达西渗流下,传统固结理论中固结时间与土层厚度平方成正比的相似关系不再满足。荷载的加荷速率越快,则土层的固结速率越快。最后,讨论了达西渗流定律在一维固结计算中的适用范围。

Habitat evaluation for target species following deep-water channel project in the Yangtze River

In order to optimize the design of a 12.5 m deepwater channel project and protect the ecological environment, it is necessary to study the habitat evaluation of species in the engineered area. A coupled eco-hydrodynamic model, which combines a hydrodynamic model （ADCIRC） and a habitat suitability index （HSI） model is developed for target fish （Coilia nasus） and benthos （Corbicula fluminea） in the Yangtze River in order to predict the ecological changes and optimize the regulation scheme. Based on the existing research concerning the characteristics of Coilia nasus and Corbicula fluminea, the relationship between the target species and water environment factors is established. The verification results of tidal level, velocity and biological density show that the proposed coupling model performs well when predicting ecological suitability in the studied region. The results indicate a slight improvement in the potential habitat availability for the two species studied as the natural hydraulic conditions change after the deep-water channel regulation works.

Evaluation of Environmental Carrying Capacity of Water Resources in Jiangxi Province

In order to quantitatively evaluate the sustainable development status of water resources in Jiangxi Province, the dynamic changes in ecological footprint, carrying capacity and load index of water resources in Jiangxi Province during 2009-2013 were analyzed according to the primary principle and calculation model of ecological footprint. The results showed that in Jiangxi Province during 2009- 2013, the water resources ecological footprint per capita was relatively low; the wa- ter resources utilization level was relatively low; the overall development potential of water resources was great; the water resources ecological carrying capacity per capita and ecological footprint per capita were trended to be increased overall. The changes in water resources ecological footprint are closely related to the social and economic development. Therefore, the industrial structure should be fully adjusted, and the water resources should be scheduled and utilized reasonably so as to pro- mote the protection of water resources and sustainable development of society and economic in Jiangxi Province.

基于综合水力性能指数的管道排水能力评估及应用研究

排水能力评估是排水管网系统规划、设计、运行和维护的基础。现有的水力性能指数(HPI)主要用于顺坡流动、管顶平接、无泵闸设施等简单树状管网的计算,为适应实际排水管网系统的各种复杂形态和工况,对现有算法进行改进,提出采用综合水力性能指数(CHPI)评估管道排水能力。CHPI由最大全局水力性能指数(MGHPI)、最大自身水力性能指数(MSHPI)和累积水力性能指数(AHPI)加权计算,既能反映管道自身超载程度,又能反映对上游管道超载的影响,同时还能兼顾管道排水能力在时间和空间上的变化,并可应对管道高程的突变。佛山三龙湾某片区8 km^(2)排水管网系统的CHPI评估结果显示,CHPI在实际管网系统排水能力评估中具有很好的应用潜力。

Chemical and Microbiological Parameters of Paddy Soil Quality as Affected by Different Nutrient and Water Regimes

A field experiment was conducted from 1999 to 2002 to compare and evaluate the effects of nutrient and water regimes on paddy soil quality by investigating soil chemical and microbiological parameters. Four nutrient regimes, a control, chemical fertilizers only (CF), chemical fertilizers with swine manure (SM), and chemical fertilizers with wheat straw (WS), and two soil moisture regimes, continuous waterlogging (CWL) and alternate wetting and drying (AWD), were investigated. With SM and WS total organic carbon and total nitrogen in the paddy soil were significantly higher (P < 0.05) than those with CF. A similar effect for organic amendments was observed in the soil light fraction organic C (LFOC), water-soluble carbohydrates (WSC), and water-soluble organic C (WSOC). CWL, in particular when swine manure was incorporated into the paddy soil, markedly decreased soil redox potential (Eh) and increased total active reducing substances (ARS). Meanwhile, as compared to CF, SM and WS significantly (P < 0.05) increased soil microbial biomass C (MBC) and mineralizable carbon, with differences in AWD being higher than CWL. In addition, SM and WS treatments significantly (P < 0.05) improved rice above-ground biomass and grain yield, with AWD being greater than CWL. Thus, for ecologically sustainable agricultural management of paddy soils, long-term waterlogging should be avoided when organic manure was incorporated into paddy soil.

A novel myeloma cell line identified for multidrug resistant study

Objective:To find out how to overcome resistance during multiple myeloma(MM) treatment through establishing a multidrug resistant human multiple myeloma cell line and investigating its biological features.Methods:The parent cell line MOLP-2 was exposed to different concentrations of melphalan and a melphalan-resistant cell line MOLP-2/R was identified by continuous stepwise selection.The cell morphology and growth curves were examined.Protein levels of P-gp, MRP and FANCD2 monoubiquitination were checked by Western blotting.The IC50 of melphalan and resistance index(RI) were detected by MTT assay.Results:A melphalan-resistant cell line MOLP-2/R was finally identified.The RI of MOLP-2/R cells to melphalan was 6.03.Besides melphalan it was cross resistant to other chemotherapeutic agents, including ADM, CTX, DDP and VP-16.The multiplication time was postponed(P < 0.05).Studies showed that FANCD2 protein monoubiquitination was enhanced, but the levels of P-gp and MRP expressions in the MOLP-2/R cells were similar with the parent cells.Conclusion:MOLP-2/R cell line may serve as an ideal model for exploring the mechanism of MDR.Over-expression of FANCD2 protein monoubiquitination might contribute to acquired drug resistance in MOLP-2/R cell line.

Projections of the 21st Century Changjiang-Huaihe River Basin Extreme Precipitation Events

Based on the 1961-1990 observed daily precipitation in the Changjiang-Huaihe River Basin, the NCEP/NCAR reanalysis data, and the HadCM3 model data for IPCC SRES A1B climate projections, the simulation capabilities of the BP-CCA downscaling approach for extreme precipitation indices of the current climate are assessed by applying canonical correlation analysis (CCA). In addition, future extreme precipitation indices in the middle and late 21st century are projected. The results show that simulation capability of the HadCM3 for regional climate characteristics can be effectively improved by the downscaling approach, with 30%-100% reduction of the relative errors of the climatological mean state of extreme precipitation indices. However, the downscaling results still show wetter winter and dryer summer than the observation. Under the SRES A1B emission scenario, frequency and intensity of extreme precipitation events are projected to increase, and the estimated increasing rate is higher for extreme precipitation indices than for mean precipitation index; and in summer than in winter. Extreme precipitations in the middle and late 21st century are expected to increase by 14% and 25% respectively in winter, and by 24% and 32% respectively in summer.

Vulnerability assessment of water resources to climate change in Chinese cities

Climate change is an inevitable trend,which challenges security of water resources in China,especially in cities.Assessing vulnerability of water resource to climate change in cities has important role for policy makers. The paper constructs a vulnerability function,including exposure,sensitivity and adaptive capacity,according to the vulnerability concept proposed by IPCC,establishes an assessment indicators system of water resources to climate change in cities,and analyzes vulnerability features of Chinese cites based on 655 cities＇data in 2006.The vulnerability assessment results show that there are distinctive differences among all the cities,between east,central and west cities,between ordinary,big and mega cities,while there is no statistical significant difference between north and south cities.Based on the research,the paper suggests that strategic emphasis should focus on the central cities and ordinary cities

Cytoskeleton Dynamics: A Continuum Cooperative Hydrolysis Model

Cytoskeleton is a network of filamentous proteins, such as actin filaments and microtubules. We propose a continuum cooperative hydrolysis model which possesses exactly analytical solution to describe the dynamics of filament. The results show that the cooperativRy leads to non negative-exponential distribution of T （ATP or GTP） subunits. As an application, we investigate the treadmilling phenomenon using our model. It is shown that the cooperativity remarkably affects the length of filament.