摘要：According to the different stress paths,similar model test and PFC simulation test of tunnel surrounding rock are designed to compare the failure mechanisms at macroscopic and mesoscopic *** following conclusions are drawn.1)Excavation unloading will disturb the surrounding rock to form a certain excavation damaged zone.2)Under the loading path,the stress of surrounding rock failure is 1.500 MPa;under the unloading path with initial stress of 60% σ_(Zmax) and 100% σ_(Zmax),the failure stress is 1.583 and 1.833 MPa respectively in the model test.3)In terms of the failure mode of rocks under different stress paths,tensile fractures first appear in two sides of the vertical walls;thereafter,the spandrel and arch foot are loosened due to the stress *** fractures gradually coalesce with those occurring in the vertical walls.4)In the process of excavation unloading,the proportion of shear cracks is 35.3%,and the rock is subject to strong shear *** final failure surface is approximately V-shaped.5)The tangential peak stress on the vertical walls at the free face is the lowest;the vertical walls at the free face show the poorest bearing capacity and are easily subjected to tensile failure.

摘要：The coverage of network resources is increasingly extensive,and computing resources have likewise gradually become fundamental infrastructures,providing ubiquitous computing ***,in wide area networks(WANs),the underlying network and computing resources are not closely investigated or co-designed,and there are still problems reflected in slow computing service scheduling,inflexible data distribution,and inefficient data transmission.

摘要：With the continuous improvement of solar energy production capacity,how to effectively use the electricity generated by renewable solar energy for electrochemical conversion of biomass is a hot *** conversion of 5-hydroxymethylfurfural(HMF)to biofuels and value-added oxygenated commodity chemicals provides a promising and alternative pathway to convert re-newable electricity into *** nickel-based eletrocatalysts are well-known for HMF oxidation,their relatively low intrinsic activity,poor conductivity and stability still limit the poten-tial ***,we report the fabrication of a freestanding nickel-based electrode,in which Ni(OH)2 species were in-situ constructed on Ni foam(NF)support using a facile ac-id-corrosion-induced *** Ni(OH)2/NF electrocatalyst exhibits stable and efficient electro-chemical HMF oxidation into 2,5-furandicarboxylic acid(FDCA)with HMF conversion close to 100%with high Faraday ***-situ formation strategy results in a compact interface between Ni(OH)2 and NF,which contributes to good conductivity and stability during electrochemical *** superior performance benefits from dynamic cyclic evolution of Ni(OH)2 to NiOOH,which acts as the reactive species for HMF oxidation to FDCA.A scaled-up device based on a continu-ous-flow electrolytic cell was also established,giving stable operation with a high FDCA production rate of 27 mg h^(-1)cm^(−2).This job offers a straightforward,economical,and scalable design strategy to design efficient and durable catalysts for electrochemical conversion of valuable chemicals.

摘要：处于高地应力环境的硬岩工程,由于开挖扰动导致围岩应力环境变化,进而发生脆性剥落破坏。线性工程沿洞线地应力场分布受到各种因素的影响,判别沿线地应力分布规律对于施工安全和衬砌支护设计具有重要意义。在介绍初始地应力分布统计规律的基础上,对地下洞室轴线与初始地应力场排布不同组合情况下,围岩二次应力场及偏应力分布规律进行了模拟研究。基于硬脆性岩石破坏准则,推导了考虑硬脆性围岩破坏宏观表征的洞轴平面初始应力场求解公式,对所推导的公式进行了工程验证,结果比较吻合。研究结果可为深埋硬岩隧道工程初始地应力场量值判别及工程支护设计提供一定的借鉴和参考。

摘要：针对紫铜薄壁微铣削加工过程中的位移变形问题,建立了铣削力数学模型,采用四边形薄板单元有限元方法对薄壁铣削的位移变形进行分析预测。为了验证铣削力模型和薄壁变形预测的准确性,利用金刚石微铣刀对紫铜进行铣削试验。最后,通过光学显微镜和扫描电镜进行观测。结果表明:本文试验结果与仿真结果几乎吻合,证明本文建立的铣削力模型及采用的薄板变形分析方式可以有效地预测加工变形,且载荷位置与薄壁变形关系密切,切削变形随薄壁厚度的减小而快速增大。

摘要：针对坐立功能障碍患者的康复训练问题,本文基于人体运动曲线的轨迹综合,设计了一种符合人机耦合性的坐立康复训练机器人。通过光学动作捕捉实验,采集人体坐立运动轨迹,选择以大腿运动轨迹作为机器人的设计目标;在六杆机构模型的基础上,基于双目标轨迹发生综合法,以大腿上近髋点与近膝点的轨迹作为机构复现的双目标轨迹,进行机构数学模型的分析计算,得出该六杆机构可实现空间内多组位置的精确轨迹综合;建立机器人三维模型,对其关键部件进行静力学仿真分析以及虚拟样机的运动仿真,验证机器人设计的可行性;进行了机器人辅助坐立实验,采集膝、髋关节的运动曲线,膝、髋关节轨迹最大偏移误差分别为12%、5.8%,整体拟合程度较好,表明所设计的机器人具有较好的人机运动协同特征。

摘要：针对IPv6路由扩展首部漏洞所带来的安全问题,设计并实现了一种适用于IPv6路由扩展首部的入侵检测机制。以开源入侵检测系统Snort为基础,不改变其原有的数据包检测规则结构,采用IPv6协议分析技术对Snort数据包解析模块进行改进。设计实现了支持IPv6路由扩展首部的解析模块、内部网络受保护系统模块(IPSM),并给出了实验验证过程和结果分析。实验证明该设计方案能准确检测出利用IPv6路由扩展首部漏洞所实施的攻击行为。

摘要：防晕型金具设计是特高压变电站电晕防治和电磁环境治理的关键,特别是在高海拔地区,电晕防治尤为重要。采用有限元仿真和试验相结合的研究方法,提出了满足工程需求的海拔校正指数公式、线性公式和金具表面场强控制值,计算获得了高海拔特高压变电站导线连接金具表面的电场分布,给出了各导线连接金具的结构优化方案并通过了高海拔电晕试验验证。结果表明:按文中推荐方法计算得到的4000m海拔校正系数为1.51,与标准Q/GDW 551—2010推荐值相差1.9%。高海拔特高压变电站中导线连接金具表面场强应进行差异化控制:上层金具不超过1.32kV/mm,局部不超过1.52kV/mm;下层金具不超过0.99kV/mm,局部不超过1.14kV/mm。采用所提推荐方案时,各导线连接金具电晕熄灭电压均高于698.5kV且保有一定安全裕度,可满足4000m高海拔特高压变电站使用要求。研究成果可为我国超高海拔地区特高压变电站的防晕型金具设计提供依据,助力我国构建绿色环保的新型能源体系。

摘要：厂区竖向设计是整个污水处理厂总图设计中一个重要环节,竖向设计对于工艺流程顺畅、管道走向、场地排雨水、建设投资、工厂的长期运营起着至关重要的作用。而场地平整(亦称"土方平衡")是竖向设计的"先锋官",场地平整的合理性直接影响到整个厂区使用性能的发挥程度,同时会造成工程量的大小变化,影响工程的经济效益。以鄂尔多斯市东胜区南郊污水处理厂为例,介绍了阶梯式场平在厂区竖向设计中的应用、适用条件及优点,对相同地形条件下的厂区竖向设计具有一定的指导意义。

摘要：利用Dimine矿业工程软件,建立大屯锡矿的三维实体模型,通过形象、直观、准确、动态地的图形数据,高效、精确地对矿体进行采矿设计,标志着大屯锡矿进入"数字矿山"的新台阶。