中国水—能源—粮食纽带系统安全水平与全要素生产率时空耦合协调关系分析

为研究中国资源系统与经济系统耦合协调发展状况,通过构建水-能源-粮食纽带系统安全评价指标体系,应用TOPSIS模型、DEA-Malmquist指数和耦合协调度模型,对中国30个省(自治区、直辖市)(不包括港澳台及西藏)水-能源-粮食纽带系统安全水平与全要素生产率进行了测算,从时间和空间的角度分析了二者耦合协调关系。结果表明：中国水-能源-粮食纽带系统安全水平呈“双极分布”的空间格局,整体安全水平逐年提升,粮食子系统安全水平最高,水资源子系统安全水平最低;2005—2019年中国全要素生产率呈波动上升态势,水-能源-粮食纽带系统与全要素生产率耦合协调时空格局差异显著,耦合协调度呈现上升趋势,空间格局由南至北呈现出“高—低—高”的空间分布特征,时间维度上耦合协调呈现向高水平耦合阶段演进的趋势。     

长江经济带水-能源-粮食系统耦合时空动态特征研究

水、能源和粮食为可持续发展的基础性资源,如何从时空角度全面评价长江经济带水-能源-粮食系统的耦合协调发展是促进区域资源可持续发展的重要前提。以水、能源、粮食以及共生单元水能、水粮和能粮系统为单元,构建水-能源-粮食系统耦合协调评价指标体系,采用熵值法对各系统指标赋权,运用耦合协调度模型和空间自相关分析对2010—2019年长江经济带的水-能源-粮食系统协调发展和时空动态特征进行定量研究。结果表明：2010—2019年长江经济带水-能源-粮食系统综合评价指数整体呈缓慢增长趋势,其中水系统对水-能源-粮食系统综合评价指数贡献最大,年均贡献占比为21.57%;能源系统贡献最小,占比为11.95%; 2010—2019年长江经济带水-能源-粮食系统耦合协调水平呈先升后降趋势,其中四川省上升幅度为5.05%,重庆市下降幅度为2.83%,且存在显著的空间异质性,上游地区明显高于中下游地区。其中能源资源是水-能源-粮食系统耦合协调发展的短板;长江经济带水-能源-粮食系统耦合协调度表现出显著空间关联性,高-高集聚区集中在长江上游地区,下游地区主要以低-低集聚区为主。长江经济带内各省市应因地制宜地完善资源管理机制,推动长江经济带资源可持续发展。     

京津冀地区水-能源-粮食系统安全耦合协调发展特征评价

以京津冀地区为研究区域,选取28个代表性指标,利用层次分析法构建水-能源-粮食耦合安全综合指标体系,运用耦合协调度模型和障碍度模型分析2000—2020年水-能源-粮食系统耦合安全性和影响因素。研究结果表明：京津冀地区水安全、能源安全和粮食安全系统综合评价指数呈整体上升的趋势,其浮动范围为0.3~0.7;水-能源-粮食系统耦合协调度年际间均呈上升趋势,北京市耦合协调度最高,河北省耦合协调度较低;人均水资源量、废水中COD排放量、人均能源消费量和亩均农用机械总动力为京津冀地区主要障碍因子。未来北京应调整用水结构、挖掘节水潜力。天津市和河北省要注重优化能源消费结构,进行低碳技术创新,加大脱碳步伐,其中河北省农业发展需要进一步采取节水灌溉措施、减少农作物受灾面积。     

中国水资源-能源-粮食纽带系统效率时空分异特征

采用SBM-DEA模型、网络DEA模型及双变量空间自相关方法对1997—2017年中国30个省级行政区的水资源-能源-粮食纽带系统(WEF系统)效率进行测度,并分析了其时空演化特征。结果表明:研究时段内,中国水资源、能源、粮食3个子系统的效率值呈现逐年上升趋势,水资源子系统、粮食子系统的效率值提升趋势明显,能源子系统效率值提升速度较为缓慢,空间分布上东部地区各子系统的效率值明显高于中部和西部地区;水资源子系统、能源子系统、粮食子系统效率值之间的空间相互作用存在一定差异,但协同作用的地区分布范围较为一致;中国WEF系统效率值呈波动上升趋势,而区域分布上,东部地区、东北地区、中部地区、西部地区的效率平均值呈依次下降的趋势,高效率区主要分布在东部沿海与黄河流域中下游地区,而西部地区则是低效率聚集区。     

我国水-能源-粮食耦合关系及影响因素

为缓解我国水、能源和粮食资源紧张问题，促进资源可持续利用，构建水-能源-粮食系统，利用耦合协调度模型对我国的30个省（自治区、直辖市）进行测算,并利用空间杜宾模型分析主要影响因素。结果表明：2003—2017年，我国能源、粮食评价[JP]指数高于水资源评价指数，系统综合评价指数逐年递增；大部分省份耦合协调度处于初级协调水平且呈现逐年上升的态势，个别省份耦合协调度濒临失调；耦合协调度空间自相关性较强，虽有明显波动，但是呈现逐年加强的态势；影响耦合协调度的主要因素有从业人口数、固定资产投资额、人均生产总值、人口总数、[JP]文盲人口占比、工业污染排放、城镇化。     

黄河流域地级市水-能源-粮食系统耦合及空间关联研究

黄河流域水资源匮乏,但肩负国家能源和粮食生产的重任。在资源有限、需求不断扩张的背景下,探究水-能源-粮食资源的空间错配给黄河流域可持续发展带来的压力和挑战,可为流域高质量发展及国家区域协调发展战略提供科学依据和参考。基于中观尺度,构建黄河流域地级市水-能源-粮食系统综合评价框架,分析了流域内各地级市的水-能源-粮食系统耦合协调发展水平及空间关联特征。结果表明：2000-2018年,流域内各地级市的水-能源-粮食系统耦合协调度整体由初级协调阶段过度到中级协调阶段,但协调发展稳定性不足,至2018年,系统耦合协调度呈现下降态势;多数年份系统耦合协调度表现出显著的空间关联特征。从地级市视角出发对水-能源-粮食系统进行研究更具地区针对性,更易凸显中观尺度下系统发展的个性特征。应进一步探究黄河流域水-能源-粮食系统的空间关联影响机制,并解构黄河流域水-能源-粮食系统动态耦合协调发展模式。     

吉林省水-能源-粮食系统耦合协调度评价研究

【目的】水、能源、粮食是保障人类生存与福祉的重要物质基础,研究吉林省水-能源-粮食系统的耦合协调发展状况,以促进吉林省水、能源、粮食的可持续发展。【方法】以吉林省为研究区,建立水-能源-粮食(W-E-F)系统综合发展评价指标体系,利用耦合协调度模型定量评价2003—2020年W-E-F系统耦合协调状况,运用GM(1,1)预测2021—2030年耦合协调度。【结果】结果表明：吉林省W-E-F系统综合发展评价指数呈现波动上升趋势,由0.29增长至0.67,其中水资源系统发展指数对综合系统发展指数影响大;耦合度在0.88～0.99范围内,处于高水平耦合阶段,耦合协调关系由勉强失衡逐步发展到中级协调水平,表现出向好的趋势,预测2030年将达到高级协调,最后为促进吉林省W-E-F系统耦合协调发展提出了相关建议。【结论】耦合协调度模型能够有效定量评价吉林省水-能源-粮食系统的协调发展状况,为吉林省水-能源-粮食系统协调发展提供科学参考。     

中国水-能-粮协调度测度及差异性优化调控

针对目前水资源-能源-粮食(Water-Energy-Food, WEF)系统协调度研究中存在的不足，构建了中国省际WEF系统协调度评价指标体系，采用综合评价模型及力学均衡模型对1997～2019年30个省(直辖市、自治区)的WEF协调度进行测度，并针对各类型区提出了相应的优化调整措施。研究结果表明：(1)研究期内，中国水资源系统、能源系统及粮食系统的评价指数均呈上升态势，东、中、西三大区域各系统的评价指数与全国变化趋势基本一致；各系统评价指数在空间分布上存在差异。(2)就协调类型而言，东部地区与中部地区除个别年份以外，其状态类型分布情况与全国状态类型分布相对一致，而西部地区则除个别年份以外均处于基本协调状态。(3)研究时段内，中国30个省(直辖市、自治区)出现高水资源系统-低粮食系统类型的次数最高，达到189次，占比27.4%,而高能源系统-低粮食系统的类型出现次数最低，仅25次，占比3.6%。基于研究结论，可针对各类型区的特点提出相应的优化调控措施，为促进中国WEF系统协调发展提供理论依据。     

山西省水-能源-粮食系统耦合协调时空变化特征研究

为探究山西省水-能源-粮食(W-E-F)系统耦合协调程度的时空变化特征,构建W-E-F系统评价指标体系,采用综合评价指数和耦合协调模型,测算全省及各地市2008-2017年W-E-F系统发展水平及其耦合协调程度,并分析其时空变动特征。结果表明:9年间全省W-E-F系统耦合协调度从0. 55上升到0. 83,总体达到良好协调水平。但各子系统发展特征不同,粮食子系统发展水平较高,表现稳定,水资源子系统发展滞后且稳定性较差。系统协调水平和各子系统的发展水平均存在显著且逐渐扩大的空间差异,2017年初级协调区和中级协调区占比分别为45%和55%。太原、忻州和晋中3市协调水平较高,协调水平较低的朔州和运城主要受能源和水资源子系统的制约;各子系统空间差异大小为能源>粮食>水资源,W-E-F各子系统发展水平最低的地区分别是运城、朔州、阳泉。大多数地区面临W-E-F系统内部发展日益失衡的问题,各子系统间存在突出的矛盾,主要表现为粮食和能源子系统与水资源子系统之间的压力和制约效应。最后提出促进山西省W-E-F系统协调发展的措施。     

区域水-能源-粮食耦合协调演化特征研究——以江苏省为例

随着我国淡水资源减少,能源需求增加,粮食供给的不确定性愈加严重。以江苏省为研究对象,通过构建水资源-能源-粮食(W-E-F)系统耦合协调评价指标体系,采用熵值法对各子系统指标赋权,利用耦合协调模型进行对协调发展水平进行定量评价,并基于灰色GM(1.1)模型预测未来5年的耦合协调度。结果表明:江苏省2000-2015年W-E-F系统的综合评价指数整体上随时间呈上升趋势;耦合度基本保持高水平耦合;耦合协调度呈倒"U"型曲线,经历了初级协调、勉强协调、中级协调3个阶段,并在未来5年内向良好协调类过渡。但水资源与能源的发展水平仍滞后于粮食,故提高水与能源的利用效率,以促进区域的可持续发展。     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。     

Desiccation and recolonization of phytobenthos in a regulated desert river: Colorado River at Lees Ferry,Arizona, USA

We tested the recolonization of the phytobenthic community in the tailwaters of Glen Canyon Dam following long- and short-term experimentally induced desiccation. The response of Cladophora glomerata, Oscillatoria spp., miscellaneous phytobenthos species and periphyton was studied over 18 weeks using three treatments: (1) undisturbed control cobbles from the submerged zone; (2) cobbles desiccated and replaced into the submerged zone; and (3) cobbles desiccated and replaced into the varial zone. Periphyton density and compositional response resulting from these treatments were also examined. Desiccation treatments were significantly different in biomass from controls throughout the study. The biomass of desiccated and replaced river cobbles averaged <30% of the controls for C. glomerata and periphyton during the 18-week recolonization period. In contrast, the biomass of the control Oscillatoria and miscellaneous phytobenthos species averaged only 3 and 50% of that in the desiccation treatments, respectively. Cladophora, the dominant alga, comprised 77% of the phytobenthic biomass. A significant positive relationship between discharge, Cladophora and periphyton biomass was present in all treatments, while there was a negative relationship with discharge for Oscillatoria and miscellaneous phytobenthos species. There was a significant inverse correlation, as well as a pattern of separate biomass dominance, between C. glomerata and Oscillatoria. Cladophora was the dominant phytobenthos species on cobbles below the baseflow and Oscillatoria was dominant on cobbles in the varial zone. In general, the Cladophora biomass decreased under intermittent drying conditions, while Oscillatoria declined under permanently wet conditions. Diatom composition was not significantly different between treatments; however, their density was lower on desiccated cobbles. Diatom density on desiccated cobbles in the submerged and varial zones averaged 69 and 42% of that of the controls, respectively. Recovery and maintenance of benthic resources are hindered by fluctuating flow regimes driven by electricity and irrigation requirements. Repeated desiccation of the phytobenthos has major effects on the bottom-up interactions in the Colorado River ecosystem. © 1998 John Wiley & Sons, Ltd.