浅谈水闸沉井基础施工技术

在钱塘江沿岸水利工程建设中，采用沉井基础，迄今有30多年的历史，作者从长期的施工实践中，摸索了一些经验与体会，主要介绍水闸的单井沉放和多井间隔沉放的沉井基础施工技术。     

居住区环境设计新思维初探──跨世纪住宅设计竞赛的思考与研究

本文结合’96上海国际住宅设计竞赛方案，就居住区环境设计的理论与方法进行了探讨。     

黄河冲淤特性"相对清水冲刷、相对浑水淤积"

本文回顾总结了以往对黄河干支流河道冲淤特性的研究情况 ,利用所提出的冲淤临界流量与含沙量的关系与渭河下游、黄河下游进行了对比。以此为基础 ,勾画出了黄河干支流冲积河道“相对清水冲刷、相对浑水淤积”的物理图景 ,提出了多沙河流“相对清水冲刷、相对浑水淤积”的冲淤特性     

怒江水电基地的电力市场研究

怒江中下游干流河段落差集中 ,水量大 ,淹没损失小 ,交通方便 ,施工条件好 ,地质条件良好。规划装机容量2 13 2 0MW ,是我国重要的水电基地之一。到 2 0 2 0年 ,澜沧江中下游、金沙江中下游以及广西水电、四川水电、贵州水电基本得到大规模的开发 ;怒江将可能成为南方电网 ,乃至华中电网电力电量平衡的必不可少的电源。怒江水电基地是南方电网长远能源平衡的战略基地 ,“西电东送”的后续基地。怒江供电区域市场空间较大 ,送到受电地区的落地电价也具备一定的竞争力     

In Vitro hydrodynamic evaluation of prosthetic polymer heart valves in steady flow

Hydrodynamic comparison of two polymer valves with two mechanical valves is presented. The valves were perfused in a steady flow system, and comparisons between the valves were made on the transvalvular pressure distribution and drop, opening area, and leakage volume. Particular emphasis was placed on a slit-type bileaflet polymer valve which was newly designed and fabricated in our research group. The results showed that the functional characteristics of a slit-type bileaflet polymer valve compared favorably with that of mechanical valves. This valve may be a viable and inexpensive alternative, especially for short-term use in TAH or VAD systems.     

棉花优质高产抗旱节水技术大田试验研究

按照生态农业工程理论和抗旱节水工程技术要求,对棉花转基因抗旱品种、不同密度、不同基肥N、P的施用量进行田间水分胁迫综合试验.经在关中灌区3年试验研究结果表明:密度以每公顷种植7.5万株比种植4.5、6万株分别增产671.854、83.30 kg,增产57.49%和41.36%.品种陕402(早熟)、陕576(中早熟)分别比中棉所41(中熟)增产16.62%和16.17%.施磷酸二铵比尿素增产,每公顷施1502、25 kg分别增产11.35%和10.53%.抗旱节水农业工程育种和农艺节水工程技术结合,不仅可降低生产成本44%~47%,还可提高产量和品质,增收1 050~5 000元/hm2,同时节约了水资源,保护了农业生态环境.     

长三角地区农作物温室气体排放特征研究

为有效指导农业温室气体减排政策的制定,本研究分别采用CH4MOD模型和排放因子法估算了2018年长三角地区农作物甲烷(CH₄)和氧化亚氮(N₂O)排放,并分析其时空分布规律,最终建立了2018年长三角地区农作物1 km×1 km网格化温室气体排放清单.研究结果表明:长三角稻田CH₄排放因子为348.54 kg／hm²,农作物N₂O排放因子为0.95 kg／hm²,与前人研究结果具有一致性.长三角地区稻田CH₄排放为176.9万t(折合约3 714.9万t CO₂当量),最主要排放源为单季稻稻田;农作物N₂O排放为15114.9 t(折合约450.4万t CO₂当量),小麦是主要贡献源.CH₄和N₂O排放均主要来源于江苏省和安徽省,且集中在4—8月.建议加强对农业温室气体排放的管控,从源头上减少农田碳氮源的输入.     

Mean waiting time evaluation of packet switches for centrally controlled PBX''s

The performance analysis of packet switched networks usually does not account for the loss of transmission bandwidth caused by the switch processing time. In wide area networks, where transmission channels are of the order of 64 kbps or less, this is a valid approach since switch processing time is negligible compared to average transmission times for packets. However, in Local Area Networks (LANs), the transmission channels are usually of the order of 1 mbps or greater and thus when evaluating the performance of a LAN that is based on a packet switch, it is necessary to consider the effect of the switch processing time which is now comparable to that of the average packet's transmission time. This paper investigates the effect of this processing time on network performance, and an exhaustive cyclic queueing algorithm to minimise this effect on overall network performance is discussed. An approximate analytical technique for evaluating the performance of such a LAN is derived. This technique makes it possible to do interactive calculations which can be used in the provisioning and configuring of such networks.     

论泾河东庄水库灰岩坝址渗漏问题

通过对泾河东庄水库灰岩坝址工程地质钻探成果特别是钻孔压水试验及水文地质成果包括区域水质、水位、水温等不连通性的分析研究,并结合流量测定三维渗漏数值模拟分析,对坝区渗漏问题进行分析和论证,进一步证明在泾河下游东庄灰岩段建坝是可行的,不会发生严重渗漏,为项目的设计、审查、决策方面参考,以促进工程前期工作的进展。     

引红济石调水工程地质特点及应对措施

陕西引红济石调水工程地质条件非常复杂,施工过程中多次出现断层破碎带塌方、突发性涌水、涌泥等地质难题。结合施工采用的方法、措施分析、研究地质特性和规律,总结施工过程中发生地质灾害的经验教训,认为可以通过加强施工过程控制来有效降低隧洞施工地质风险和灾害发生的可能,从而达到加快工程建设进度,节约工程投资的目的。