盾构隧道施工物料无人运输发展现状及关键技术

盾构隧道施工物料无人运输有助于提升运输效率、降低运输成本、减少运输安全事故率。与公路汽车无人驾驶、港口车辆无人驾驶、轨道交通无人驾驶等逐步成熟的无人驾驶技术不同，在隧道场景下实施施工物料无人运输存在运输物料种类繁多、运输调度困难、地下定位信号拒止、狭窄车道频繁会车、行车路面工况复杂、地上地下联动响应慢等诸多挑战。从实现盾构隧道施工物料无人运输的关键问题分析入手，综述当前盾构隧道施工物料运输方式、运输需求、无人运输发展现状及存在的挑战，提出盾构隧道施工物料无人运输的五大关键技术：多种类物料智能货控能效管理技术，无人化垂直装卸门机控制技术，多传感器融合同步定位与地图构建技术，隧道复杂环境路径规划与自主避障技术，隧-地一体化联动响应的高可靠性无线通信技术。     

浅议生态环境监测机构的风险控制

现阶段,为了探索创新性的发展途径,生态环境监测机构应始终增强风险控制意识。应加强风险管理,立足于风险控制,以求不断健康发展。     

Evolution mechanism of the microstructure and mechanical properties of plasma-sprayed yttria-stabilized hafnia thermal barrier coating at 1400 °C

Yttria stabilized hafnia (Hf_0.84Y_0.16O_1.92, YSH16) coatings were sprayed by atmospheric plasma spraying (APS). The effects of thermal aging at 1400 °C on the microstructures, mechanical properties and thermal conductivity of the coatings were studied. The results show that the as-sprayed coating was composed of the cubic phase, and the nano-sized monoclinic (M) phase was precipitated in the annealed coating. The presence of M phase effectively constrained the sintering of the coating due to its superior sintering-resistance. The Young's modulus kept at a nearly same level of ~78 GPa even after annealing, and the coating annealed for 6 h yielded a maximum value of hardness but revealed a declining tendency in the Vicker's hardness with prolonged sintering time. The thermal conductivity increased from 0.8-0.95 W m^-1 K^-1 at as-sprayed state to 1.6 W m^-1 K^-1 after annealing at 1400 °C for 96 h. The dual-phase coating is promising to serve at temperatures above 1400 °C due to its excellent thermal stability and mechanical properties.     

峡口水库沥青混凝土面板的施工与试验

以灌溉、防洪为主的峡口水库大坝，为沥青混凝土面板堆石坝，为研究低温抗裂性能，对沥青混凝土面板破损取样，进行了配比和多种力学性能试验，并与原面板设计指标进行了对比。由于面板经受住了－20℃以下的低温考验，其所用沥青指标、破损取样试验结果，特别是冻断低温指标，对确定水工沥青混凝土低温抗裂检验标准有重要参考价值。     

Material removal and surface damage in EDM of Ti3SiC2 ceramic

Material removal and surface damage of Ti₃SiC₂ ceramic during electrical discharge machining (EDM) were investigated. Melting and decomposition were found to be the main material removal mechanisms during the machining process. Material removal rate was enhanced acceleratively with increasing discharge current, i_e, working voltage, u_i, but increased deceleratively with pulse duration, t_e. Microcracks in the surface and loose grains in the subsurface resulted from thermal shock were confirmed, and the surface damage in Ti₃SiC₂ ceramic led to a degradation of both strength and reliability.     

水上地震折射互换法误差分析

在理论上，用源检互换的方法进行折射地震勘探是没有误差的，在某些特殊条件下无法铺设检波器而又必须进行折射地震勘探时它也是唯一的选择，然而，在实际工作中，由于各种因素的影响，其误差是不可忽略的。为此，本文从地震折射运动学的角度对水上地震折射互换法因过河钢丝绳的重量、水的流速和流向、炮点深度等客观因素造成的解释误差进行了分析，揭示了水上地震折射互换法应注意的问题。这对水上地震折射互换法的资料解释进行误差校正提供了理论基础。     

WO3/CeO2/YSZ nanocomposite as a potential catalyst for methanol reforming

A WO₃/CeO₂/YSZ nanocomposite material [W/Zr nominal atomic ratio = 0.025, Ce/Zr nominal atomic ratio = 0.020] was prepared by wet impregnation and characterized by means of X-ray photoelectron and diffuse reflectance infrared Fourier transform spectroscopic techniques, X-ray diffraction and thermal analysis.Both tungsten and cerium oxides are significantly reduced at the interface with YSZ: Ce(III), in particular, seems to be the prevailing species.The interaction of the WO₃/CeO₂/YSZ nanopowder with pyridine and CO₂ allowed to investigate the acidic/basic sites. Weak contributions at 1602, 1625 and 1647 cm⁻¹ suggest the presence of Lewis and Brønsted acidic sites, whereas basic sites are not evidenced by the interaction with carbon dioxide. The presence of tungsten oxide causes the decrement of the acidic/basic sites, as indicated by the comparison with the results obtained on the CeO₂/YSZ support. Consistently, the interaction with methanol is mainly molecular.The oxidation of methanol was investigated both in the absence and in the presence of water. In the last case carbon dioxide starts forming from room temperature.     

A novel dual-biological-community swarm intelligence algorithm with a commensal evolution strategy for multimodal problems

The Journal of Supercomputing - For sophisticated applications, engineers should always consider multi-objective, multi-task or multi-modal problems, especially in the Internet of Things, such as...     

iPad客户满意度研究

通过对用户对ipad认知、体验等各个方面的研究,了解客户满意度,从品牌影响力、购买倾向、购买渠道、用户体验和受访者特征5个维度进行分析,从而改善用户满意度及销售计划。