水利工程水闸计算浅析

随着水闸工程建设的日益增多,水闸工程设计质量要求也越来越高。水闸设计当中,闸室的稳定计算有一定的难度,本文结合工程实例进行分析,总结出计算的详细过程,以提高水闸闸室的稳定性,供同类工程参考。     

浅析秦望闸工程施工关键技术及要点

本人结合富阳秦望闸工程施工经验及相应规范,分析了水闸基础施工、水闸施工及闸室施工等关键施工环节,探讨了水闸工程的施工技术要点,为水闸工程施工提供质量保证措施建议。     

水闸基坑支护连续墙施工方案分析

水利枢纽工程中,水闸应用广泛,其中闸室基坑支护的钢筋混凝土连续墙方案也多被运用。此种施工方案比较复杂,若不能控制好,将很大程度的影响工程质量。本文就此方面进行分析探讨,以供同类工程施工参考。     

汉川闸除险加固设计

汉江穿堤水闸除险加固设计方案,老闸闸体结构已遭到严重损坏,闸体的防洪能力已基本丧失,结合工程实际,封堵老闸两边孔,接长中孔涵洞,新建进口闸室,在确保工期和工程安全的前提下,完成了工程加固。     

水利工程连续墙施工技术方案探讨与分析

水利枢纽工程中，水闸应用广泛，其中闸室基坑支护的钢筋混凝土连续墙方案也多被运用。此种施工方案比较复杂，若不能控制好，将很大程度的影响工程质量。本文就此方面进行分析探讨，以供同类工程施工参考。     

提高水闸结构耐久性技术措施分析

水闸结构耐久性是衡量水利工程质量的重要指标。本文分析了影响水闸结构耐久性的常见环境因素,研究了混凝土碳化的机理,并对提高水闸结构耐久性进行技术措施分析。     

水闸结构耐久性影响因素及其控制措施

在影响水闸耐久性的各种原因中,混凝土结构的耐久性对水闸结构具有深远影响,本文从多年的实际工作经验出发,对水闸结构耐久性以及破坏机理进行了阐述,并对如何提高水闸结构耐久性的一些控制措施进行了简单介绍。     

水闸安全评估方法研究现状

经过二十多年的研究,我国现有在水闸评估研究的的方法有传统理论的、实用鉴定的和与其他学科相交叉的评估方法,主要介绍了传统评估方法中的整体评估法、模糊集论评估法、结构可靠度法、专家系统法、灰色评估法;与新型评估方法中的神经网络评估法、经济分析法、风险评估法,最后对建立一种经济合理适应小型水闸评估的评估方法提出期望。     

水闸结构的耐久性影响因素分析及其控制措施

水闸结构的耐久性主要反映在混凝土结构的耐久性上,文中分析了混凝土结构耐久性的影响因素及其破坏机理,结合现有的实际生产经验,提出了提高水闸结构耐久性的一些控制措施。     

利用直列装药爆破拆除钢筋混凝土水闸

我们应邀在江苏南通地区通扬河流域,利用爆破法拆除了一废弃钢筋混凝土水闸。根据水闸岸墙与翼墙均属薄壁结构的特点,我们做了现场爆破试验,确认采用直列装药     

Plasma/reactor walls interactions in advanced gate etching processes

Wafer-to-wafer reproducibility is a major challenge in gate etching processes. Periodic dry cleaning of the reactor in F-based chemistry between wafers is the most common strategy to ensure process repeatability. However X-ray Photoelectron Spectroscopy analysis of the chamber walls show that this cleaning procedure leaves AlF_x species on the reactor walls, eventually resulting in process drifts and formation of particles. We have thus investigated a new cleaning/conditioning strategy of plasma etching reactors, in which the chamber walls are coated by a carbon-rich film between each wafer, allowing stable processing conditions and highly anisotropic etching profile to be achieved in advanced gate stacks. Finally, we present a new method (based on the detection of Cl₂ by laser absorption) to characterize the reactor walls conditions that could prevent process drifts.     

Electrostatics of partially gated carbon nanotube FETs

The finite-element method is used to solve Poisson's equation, under equilibrium conditions, for coaxial carbon nanotube field-effect transistors in which the gate electrode does not entirely cover the nanotube channel between the source- and drain-end contacts. A conformal transformation is applied to overcome the problems that arise in this open structure of specifying boundary conditions and of terminating the model space. The effect on the potential distribution within the transistor of changing various geometrical properties of the device is investigated, and some special conditions under which appropriate boundary conditions may be defined a priori are identified. The effects on the potential energy profile along the nanotube of varying the work function of the end contacts, and of introducing charge into the gate dielectric, are also investigated. The latter is shown to be effective in suppressing the otherwise dominant role that the end contacts play in determining the barrier to charge flow in the nanotube, thereby allowing bulk control to occur.     

深覆盖非均质复杂结构围堰拆除爆破设计

官地水电站尾水出口围堰具有深覆盖、非均质、卸荷基岩、堰体结构复杂的特点,围堰距离出口闸门及启闭机距离≤30m,闸室与围堰间明渠底板为1:4倒坡,明渠结构混凝土与围堰相接,与对岸拌合楼距离≤90m,爆破拆除规模大、要求高。介绍了该围堰爆破的方案选择、参数及起爆网路设计,爆破安全防护和施工技术措施,可供类似工程参考。     

低温真空腔体结构设计及传热分析

为适应未来航天低温光学系统的需要,研制了1套测量光学元件低温场和低温变形的系统。该系统由真空机组、低温真空腔体、防振系统、测量装置等主要部分组成。其中低温真空腔体是该系统中关键的装置,为光学元件的低温真空实验提供了必要的条件。对低温真空腔体的结构设计、真空度和传热进行了分析探讨,并且对梯形薄壁绝热支撑进行了详细结构热分析和COSMOSWORK软件的传热分析,结果表明可以满足低温真空的实验要求。     

露天矿高深溜井降段技术

露天矿采区内的溜井,随开采台阶面的下降需要降段。甘肃某露天矿山采区内的3#、4#溜井,其溜井深度均在400m以上,且区域地质结构复杂,井壁采用800mm厚钢钎混凝土支护,降段技术要求高、施工难度大,不能采用以往的以溜井口为自由面进行爆破降段,据此提出了一种先通过掘沟爆破为溜井降段提供自由面,再采用预裂爆破技术保护溜井支护体的完整性,最后通过深孔爆破和浅孔爆破相结合,完成溜井全降段的综合性降段技术。实践应用表明,该综合技术不仅满足了安全生产要求,而且取得了良好的爆破效果和经济效益。     

一种新型闸门力学性能的理论和试验研究

新型双拱钢管结构闸门是大跨空间结构在水工闸门中一个新的应用,将在被誉为"中国河口第一水闸"的曹娥江大闸作为挡潮泄洪闸门首次使用。该文以曹娥江挡潮泄洪闸门为原型对这种闸门进行了力学性能的试验和理论研究,首先进行了缩尺模型试验,试验结果分析表明双拱钢管结构闸门的主要受力构件为正拱、反拱和弦杆,它们组成了共同受力系统,以承受轴向应力为主,沿跨度方向受力均匀,材料的利用率高,这说明其形体是合理和优化的。进一步分析其承载特性,发现承载特性可以分为三个阶段:弹性、局部塑性和破坏阶段,拱脚和正拱、反拱交叉节点是薄弱之处,最先破坏。接着对闸门主要受力构件进行了简化理论分析,得出了理论计算公式,并和有限元计算做了比较,验证其精度满足工程要求。     

An improvement to the space resolution of charged tracks

A simple tracking method is to look for the U, X and V triple coincidences in a wire chamber, but the space resolution is in general not satisfactory. In this paper, we consider the use of space correction for the inclined planes in a chamber. The resolution can be much improved for both the proportional chamber and the drift chamber. For proportional chambers, the combination of this method and the wire-spacing “drift distance” technique, further improved the resolution.     

Bottom-gated epitaxial graphene

High-quality epitaxial graphene on silicon carbide (SiC) is today available in wafer size. Similar to exfoliated graphene, its charge carriers are governed by the Dirac-Weyl Hamiltonian and it shows excellent mobilities. For many experiments with graphene, in particular for surface science, a bottom gate is desirable. Commonly, exfoliated graphene flakes are placed on an oxidized silicon wafer that readily provides a bottom gate. However, this cannot be applied to epitaxial graphene as the SiC provides the source material out of which graphene grows. Here, we present a reliable scheme for the fabrication of bottom-gated epitaxial graphene devices, which is based on nitrogen (N) implantation into a SiC wafer and subsequent graphene growth. We demonstrate working devices in a broad temperature range from 6 to 300 K. Two gating regimes can be addressed, which opens a wide engineering space for tailored devices by controlling the doping of the gate structure.     

准预裂爆破在大型硐室开挖中的应用

简要介绍了南芬铁矿胶带运输排岩系统1#胶带驱动站硐室开挖的施工顺序,详细地阐述了采用准预裂爆破技术控制硐室超挖的施工方法.     

High-performance polycrystalline silicon thin-film transistors with oxide-nitride-oxide gate dielectric and multiple nanowire channels

This work presents a method to enhance the performance of polycrystalline silicon thin film transistors (poly-Si TFTs) by using an oxide-nitride-oxide (ONO) gate dielectric and the multiple nanowire channels structure. Experimental results indicate that the performance of the device was enhanced by using the ONO multilayer, because the ONO gate dielectric constant is increased compared to the conventional oxide gate dielectric. Additionally, the TFTs with a ten nanowire channel structure (NW-TFTs) have superior electrical characteristics compared to other TFTs. This is because a structure with more corners and a shorter radius has better gate control due to the corner effect.