摘要：Sudden earthquakes pose a threat to the running safety of trains on high-speed railway bridges,and the stiffness of piers is one of the factors affecting the dynamic response of train-track-bridge *** this paper,a experiment of a train running on a high-speed railway bridge is performed based on a dynamic experiment system,and the corresponding numerical model is *** reliability of the numerical model is verified by ***,the experiment and numerical data are analyzed to reveal the pier height effects on the running safety of trains on *** results show that when the pier height changes,the frequency of the bridge below the 30 m pier height changes greater;the increase of pier height causes the transverse fundamental frequency of the bridge close to that of the train,and the shaking angle and lateral displacement of the train are the largest for bridge with 50 m pier,which increases the risk of derailment;with the pier height increases from 8 m to 50 m,the derailment coefficient obtained by numerical simulations increases by 75% on average,and the spectral intensity obtained by experiments increases by 120% on average,two indicators exhibit logarithmic variation.

摘要：Water-coupled charge blasting is a promising technique to efficiently break rock *** this study,numerical models of double boreholes with water-coupled charge are established using LS-DYNA and are calibrated by the tests of rock masses subjected to explosion loads to examine its *** crack levels of rock mass induced by water-coupled charge blasting and air-coupled charge blasting are first *** is found that water-coupled charge blasting is more appropriate to fracture deep rock mass than air-coupled charge *** addition,the effects of rock properties,water-coupled charge coefficients,and borehole connection angles on the performance of water-coupled charge blasting are *** results show that rock properties and water-coupled charge coefficients can greatly influence the crack and fragmentation levels of rock mass induced by water-coupled charge blasting under uniform and non-uniform in-situ ***,changing borehole-connection angles can only affect crack and fragmentation levels of rock mass under non-uniform in-situ stresses but barely affect those under uniform in-situ stresses.A formula is finally proposed by considering the above-mentioned factors to provide the design suggestion of water-coupled charge blasting to fracture rock mass with different in-situ stresses.

摘要：Non-pillar mining technology with automatically formed roadway is a new mining method without coal pillar reservation and roadway *** stability control of automatically formed roadway is the key to the successful application of the new *** order to realize the stability control of the roadway surrounding rock,the mechanical model of the roof and rib support structure is established,and the influence mechanism of the automatically formed roadway parameters on the compound force is *** this basis,the roof and rib support structure technology of confined lightweight concrete is proposed,and its mechanical tests under different eccentricity are carried *** results show that the bearing capacity of confined lightweight concrete specimens is basically the same as that of ordinary confined concrete *** bearing capacity of confined lightweight concrete specimens under different eccentricities is 1.95 times higher than those of U-shaped steel *** comparing the test results with the theoretical calculated results of the confined concrete,the calculation method of the bearing capacity for the confined lightweight concrete structure is *** design method of confined lightweight concrete support structure is established,and is successfully applied in the extra-large mine,Ningtiaota Coal Mine,china.

摘要：The problems associated with vibrations of viaducts and low-frequency structural noise radiation caused by train excitation continue to increase in importance.A new floating-slab track vibration isolator-non-obstructive particle damping-phononic crystal vibration isolator is proposed herein,which uses the particle damping vibration absorption technology and bandgap vibration control *** vibration reduction performance of the NOPD-PCVI was analyzed from the perspective of vibration *** paper explores the structure-borne noise reduction performance of the NOPD-PCVIs installed on different bridge structures under varying service conditions encountered in practical engineering *** load transferred to the bridge is obtained from a coupled train-FST-bridge analytical model considering the different structural parameters of *** vibration responses are obtained using the finite element method,while the structural noise radiation is simulated using the frequency-domain boundary element *** the particle swarm optimization algorithm,the parameters of the NOPD-PCVI are optimized so that its frequency bandgap matches the dominant bridge structural noise frequency *** noise reduction performance of the NOPD-PCVIs is compared to the steel-spring isolation under different service conditions.

摘要：The practical engineering applications of powder metallurgy (PM) Ti alloys produced through cold compaction and pressure-less sintering are impeded by poor sintering densification, embrittlement caused by excessive O impurities, and severe sintering deforma-tion resulting from the use of heterogeneous powder mixtures. This review presents a summary of our previous work on addressing the above challenges. Initially, we proposed a novel strategy using reaction-induced liquid phases to enhance sintering densification. Near- complete density (relative density exceeding 99%) was achieved by applying the above strategy and newly developed sintering aids. By focusing on the O-induced embrittlement issue, we determined the onset dissolution temperature of oxide films in the Ti matrix. On the basis of this finding, we established a design criterion for effective O scavengers that require reaction with oxide films before their dissol-ution. Consequently, a ductile PM Ti alloy was successfully obtained by introducing 0.3wt% NdB6 as the O scavenger. Lastly, a powder- coating strategy was adopted to address the sintering deformation issue. The ultrafine size and shell-like distribution characteristics of coating particles ensured rapid dissolution and homogeneity in the Ti matrix, thereby facilitating linear shrinkage during sintering. As a result, geometrically complex Ti alloy parts with high dimensional accuracy were fabricated by using the coated powder. Our fundament-al findings and related technical achievements enabled the development of an integrated production technology for the high-performance and accurate shaping of low-cost PM Ti alloys. Additionally, the primary engineering applications and progress in the industrialization practice of our developed technology are introduced in this review.

摘要：黏滑作用下走滑断层将出现永久性的错动位移,当隧道与此类断层相交时将发生严重破坏,并且具有明显的分区特征。为了揭示隧道纵向和横断面的分区破坏机理,为穿越活动断裂带隧道抗震设计提供支撑,本文首先通过震害实例调研总结得到隧道的三种破坏模式,即环向裂缝、斜向裂缝和纵向裂缝。给出并讨论了断层类型、交角、错动量和隧道刚度等关键影响因素。结果表明:1)断层类型是影响隧道力学响应和安全性的最显著因素,而倾角影响很小;2)受左旋走滑断层黏滑作用的隧道沿纵向可分为弯曲-压缩-剪切(L-BCS)区和弯曲-压缩(L-BC)区,而受右旋走滑断层黏滑作用的隧道可分为弯曲-拉伸-剪切(L-BTS)区和弯曲-拉伸(L-BT)区;3)L-BCS区和L-BTS区的范围为1.4D~1.7D(D为隧道直径),而L-BC区和L-BT区范围随关键影响因素变化而变化;4)隧道横断面可分为偏心受压(C-EC)区和偏心受拉(C-ET)区,分别发生偏心受压破坏或偏心受拉破坏。C-EC区和C-ET区的范围约为距断层面5D;5)穿越左旋走滑断层隧道的C-EC区包括上盘左拱腰、下盘右拱腰、拱顶和仰拱,C-ET区包括下盘左拱腰和上盘右拱腰。穿越右旋走滑断层隧道的横断面分区分布与左旋对称。

摘要：薄煤层N00工法的提出,革新了传统的煤矿开采模式、关键技术与装备系统,并取得了成功应用。而新开采模式下的巷道围岩控制技术尚不完善,为实现薄煤层N00工法巷道顶板结构的安全稳定,考虑其工艺流程和顶板变形特点,将巷道划分为超前硐室、垮落成巷两个阶段。并基于Hoek-Brown非线性岩体强度破坏准则,确定了巷道顶板不同阶段的锚杆/索预紧力的计算公式,提出了巷道顶板锚杆/索预紧力及长度设计方法。此外,结合数值模拟研究了不同阶段巷道顶板锚杆/索支护作用机理及不同锚杆/索支护组合对围岩应力分布的影响,揭示了锚杆/索支护关键参数对顶板稳定性的影响机制。最后,综合理论与数值模拟分析结果,提出了分区补偿支护技术,确定了锚杆/索预紧力、长度及选材的设计原则,该技术在现场取得了良好的应用效果。

摘要：Short-range ordering(SRO)is one of the most important structural features of high entropy alloys(HEAs).However,the chemical and structural analyses of SROs are very difficult due to their small size,complexed compositions,and varied *** electron microscopy(TEM)as well as its aberration correction techniques are powerful for characterizing SROs in these compositionally complex *** this short communication,we summarized recent progresses regarding characterization of SROs using TEM in the field of *** using advanced TEM techniques,not only the existence of SROs was confirmed,but also the effect of SROs on the deformation mechanism was ***,the perspective related to application of TEM techniques in HEAs are also discussed.

摘要：固态锂离子电池被认为是可穿戴电子设备的理想储能器件.然而,高的电极/电解质界面阻抗仍是该领域一个严峻的挑战,尤其在弯曲变形条件下.本文提出全同源策略,利用热塑性聚氨酯作为固态电解质和电极的离子导电框架,构建具有低界面阻抗的柔性固态锂离子电池.实验结果表明,聚氨酯中-C=O、-NH和-C-O-C-等功能基团有助于锂离子传输.利用该特性,制备出具有高柔韧性和离子电导率的聚氨酯基固态电解质,以及具有优异柔韧性的复合电极,其即使在不同形变下仍能保持良好的电化学性能.在此基础上,成功组装了全同源的柔性固态锂离子电池,其表现出更低的界面阻抗和更优异的电化学性能.这种全同源策略为柔性固态电池的设计提供了一种新思路.

摘要：针对大断面隧道初期支护拱架在承载时易发生平面外失稳的问题,本文通过开展单拱架全比尺试验和考虑纵向连接的拱框架结构的数值试验以及现场对比试验,对纵向连接与拱架组成的拱框架结构进行优化研究,使其横向上有足够承载能力、纵向上有较高稳定性。研究结果表明,单个拱架的破坏模式是局部面外失稳导致整体承载力丧失,考虑纵向连接的拱框架结构的平面内承载力和平面外稳定性都得到增强。通过调整纵向连接间距和拱架间距也可以调整初期支护拱框架结构和喷射混凝土的内力分担比,以充分发挥初期支护的承载能力,但纵向连接间距应小于1500 mm,拱架间距也应小于1200 mm。因而,在不改变初期支护现有结构形式的前提下,通过合理地布设纵向连接与拱架形成的具有空间承载效应的拱框架结构,不仅可以保证初期支护的承载能力,而且还提高施工效率和经济效益。研究成果可指导大断面隧道初期支护结构设计。