摘要：在深部开挖工程中,深部岩石往往经历“三轴高应力+开挖卸荷+动力扰动”的全应力过程。为了研究围压卸荷对深部预应力岩石的动态破坏特征的影响,采用改进的分离式霍普金森压杆对红砂岩进行了一系列三轴卸荷动态压缩试验,还进行了单轴预应力冲击压缩试验(不考虑围压卸荷效应)。结果表明,红砂岩的动态抗压强度表现出明显的应变率效应。在应变率近似相等的情况下,三轴卸荷动态压缩试验中岩石的动态强度小于单轴预应力冲击压缩试验中岩石的动态强度。围压卸荷造成明显的强度弱化效应,并采用动态强度弱化因子(DSWF)量化强度弱化程度。在同一个应力路径下,岩石的应变率和入射能呈对数关系;而在入射能相同时,卸荷会导致预应力岩石有着更高的应变率。分析了试样的破坏模式,发现卸荷对试样破坏模式的影响并不显著。此外,讨论了围压卸荷对剪切强度参数(内聚力和摩擦角)的影响。在入射能相同时,发生卸荷后的预应力岩石更容易发生破坏。因此,在深部岩石工程开挖设计中应考虑卸荷对岩石力学特性的影响。

摘要：Biological world always provides inspirations for engineering designs, and insects are important targets to mimic. For the Coleoptera, its flight has been emphasized for long. However, the invisible folding procedure of hind wings, which occurs under the stiff elytra after flight, still remains unknown. In this paper, the wing folding process and the surficial microstructures of elytra, hind wing and abdomen are investigated by video recording and scanning electron microscopy. The results show that there are hooklike protrusions approximately 15 lm in length distributing on the inner side of elytra, and bump-like protrusions on the hind wings. The ‘hooks' may anchor the ‘bumps' on the main wing to prevent corrugation during folding. The horizontal protrusions observed on the abdomen shape a hairy cuticle, which is conducive to a better wing-abdomen interaction. Thus, the ratcheting mechanism that wing folding facilitated by micro-protrusions on the body surface is revealed. This new finding helps us to further understand the functions of diversely shaped protrusions in the physiology of insects. More importantly, the ratcheting mechanism could serve as a cuticle interaction model and inspire new engineering applications, such as microsystems.

摘要：在 Daya 海湾实验的成功以后， Jiangmen 地下的中微子天文台(Jupiter 之妻) 被发射测量中微子团层次和摆动参数并且学习另外的中微子物理。它的中央察觉者从反应堆，地球，空气，和阳光被放为反中微子。中央察觉者的主要要求是液体闪烁器的 20 kt 的抑制，作为目标团，和 3% 精力分辨率。它关于有它的内部表面上的 PMT 的 75% 范围的 38.5 m 的一个球形状察觉者。因为它必须为物理测量的几种不同类型满足要求并且在它的结构和工程拥有可行性和可靠性，如此的一个巨大的察觉者的设计是大挑战，都在合理时间和费用。为 JUNO 中央察觉者的一种选择是超丙烯酸的球在水里沉没了防护背景。这份报纸为如此的一个丙烯酸的球建议一个结构的计划那被支持由一不锈钢捆绑，在土木工程由支持点的眼镜窗帘墙启发了。计划的初步的设计被有限元素(FE ) 用 ABAQUS 完成并且验证方法。FE 分析证明计划能在 5 ～ 10 MPa 的限制以内控制丙烯酸的球的压力水平，根据中央察觉者的设计目的需求。计划具有突出的全球稳定性并且在本地连接上允许各种各样的选择。我们证明计划可行性好并且应该是为中央察觉者的一种合理选择。

摘要：According to the shearing force character and the deformation coordination condition of shell at the station of supports, the mathematical models to calculate contact angle and contact pressure distribution between tyre and shell were set up, the formulae of bending moment and bending stress of tyre were obtained. Taking the maximum of tyre fatigue life as the optimal objective, the optimization model of tyre support angle was built. The computational results show that when tyre support angle is 30°, tyre life is far less than that when tyre support angle is optimal, which is 35.6°, and it is unsuitable to stipulate tyre support angle to be 30° in traditional design. The larger the load, the less the nominal stress amplitude increment of tyre, the more favorable the tyre fatigue life when tyre support angle is optimal.

摘要：The hydrogen leakage detection and alarm processing system is established for the fuel cell (FC) power train lab to meet the hydrogen safety demand of the FC performance test and examination for the project named "Research and Development of the Vehicular Technology for the Fuel Cell City Bus" by Tsinghua University. The established hydrogen safety system includes the hydrogen supply system, hydrogen leakage detection system, alarm processing system, ventilation system, measures against electrostatic, thunder-arresting and explosion-protection, and the strict hydrogen operation rules. In this safety system, the explosion proof catalytic combustion sensors are used to detect the hydrogen leakage and the electrical control system is designed to process the alarm automatically. The hydrogen safety system plays an important role in the performance, examination of the FC and the assuring the personnel's safety of the fuel cell power train lab. © by HIGH TECHNOLOGY LETTERS PRESS.

摘要：In order to settle the mining optimization design and safety problem of the above 1 150 m pillar of No.1 ore-body in No.Ⅱ Mining Jinchuan, the lean-ore above 1 250 m, the 1 150 m horizontal pillar and the ore-body below 1 100 m regarded as research objects based on the original design project, and nine calculation schemes on different mining sequence and different fill body strength were put forward based on cement-sand ratio of 1:4, 1: 12 and 1: *** parameters were got by the back analysis method of field monitoring data, and the FLAC^(2D) program was applied to compute for these schemes,stress and displacement of ground settlement, shaft and stope roof were analyzed, and some conclusions were *** show that the intensity of filling body and the mining technique have very important effect on controlling settlement and stability of surrounding rock;Developing of lean ore have some influences to the 16th return air filling shaft, especially for 1 500～1 400 m of the shaft;The best project is the first *** research supply some technique references and safety appraisals for the mining of lean-ore of No.Ⅱ Mining Jinchuan.

摘要：Aiming at the large deformation and support problems of high-stress and broken-expansion surrounding rock, and taking 1 000 m level roadway of Mine II in Jinchuan as the research object, an investigation on the deformation and damage of roadway surrounding rock and an analysis of its mechanism were carried out. The gray correlation theory was used in support scheme optimization design. First, causes and mechanism of deformation of the 1 000 m horizontal transport channel were analyzed through field investigation, laboratory test and data processing methods. We arguued that poor engineering geological conditions and deep pressure increases were the main factors, and the deformation mechanism was mainly the ground deformation pressure. Second, the gray correlation theory was used to construct supporting optimization decision method in the deep roadway. This method more comprehensively considers various factors, including construction, costs, and supporting material functions. The combined support with pre-stressed anchor cables, shotcrete layer, bolt and metal net was put forward according to the actual roadway engineering characteristics. Finally, 4 support schemes were put forward for new roadways. The gray relational theory was applied to optimizing the supporting method, undertaking technical and economic comparison to obtain the correlation degree, and accordingly the schemes were evaluated. It was concluded as follows: the best was the flexible retaining scheme using the steel strand anchor; the second best was the one using plate anchors on the top and rigid common screw steel bolt on the two sides; the third was; the rigid common screw steel bolt in full section of roadway; and the worst is the planished steel rigid support. The optimized scheme was applied to the 1000 m level of new excavation roadway. The results show that the roadway surrounding rock can reach a stable state after 5 to 6 months monitoring, with a convergence rate less than 1 mm/d.