第八届全国工程爆破学术会议征文通知

介绍了在复杂环境中采用控制爆破技术拆除2组钢筋混凝土结构楼梯扶手,论述了工程方案参数设计及主要安全措施。拟拆除扶手为钢筋混凝土墙体,厚30cm,墙体布置2层钢筋,纵向钢筋为Φ15mm,间距15cm,横向钢筋为Φ12mm,间距20cm,因墙体较薄,钢筋密集,沿墙面水平向钻孔,施工难度大,采取剔除墙端部箍筋,沿墙体垂直钻孔,孔间距30cm,采用不耦合装药结构。扶手墙体不规则,需分区段确定孔深,由于扶手底座混凝土需要保护,孔底填充缓冲材料,采用非电导爆管雷管逐段孔外接力起爆。利用炮被(橡胶轮胎制作)进行覆盖防护,使爆破飞石控制在被爆体周围2³m范围内,同时在距被爆体周围2m范围搭设防护排架,铺设竹席、棉被和草帘等进行隔离防护,确保爆破飞散物不飞出防护层外,爆破后达到预期的爆破效果。     

地铁列车-嵌入式轨道系统动力学性能研究I：理论建模、试验分析及验证

嵌入式轨道作为一种减振降噪轨道结构型式，通常是基于城市街道路面的低地板有轨电车系统设计的，而嵌入式轨道的连续支承特性及其减振降噪优点使其在地铁中具有较好的应用前景。嵌入式轨道在地铁中应用，将面临更高运行速度、更大轴重、更复杂线路条件等挑战，地铁列车-嵌入式轨道系统的动力学行为有待研究。建立地铁列车-嵌入式轨道系统的动力学模型，模型包括轨道系统模型、列车系统模型以及轮轨相互作用模型。其中，轨道子系统为嵌入式轨道系统，是建模和研究的重点。模型考虑了TIMOSHENKO钢轨模型、等效弹簧-阻尼单元支承的柔性轨道板模型、以及钢轨周围的填充材料模型，填充材料模型采用考虑质量的黏弹性弹簧-阻尼单元来模拟以考虑填充材料的惯性、弹性和阻尼特性。在我国首例运用于地铁的嵌入式轨道试验线开展了动力学性能试验研究，基于试验分析了动力学性能并通过试验验证了动力学模型的有效性，建立的分析模型和相关结论为嵌入式轨道结构在我国地铁的应用提供了理论基础和参考。     

水平井配汽三维物理模拟实验

水平井注汽物理模拟实验是模拟油田实际注汽过程的有效手段，国内外学者针对水平井配汽效果开展了许多实验研究，但现阶段缺少水平井配汽结构影响配汽效果的相关研究。通过构建三维实验模型，设计注汽井配汽结构，开展了不同配汽结构下的三维注汽实验。实验结果表明，不同配汽结构对配汽效果影响较大，其中割缝管柱实验配汽效果最差，注汽井附近储层发生汽窜的时间较早；均匀开孔管柱和趾端附近射孔加密管柱实验储层发生汽窜的时间较晚，储层动用范围更广；进行趾端附近配汽实验时，随着配汽量增大，会造成蒸汽回流；当配汽孔沿水平井方向均匀分布时，虽然在注汽前期可以较为均匀地分配蒸汽，但随着注汽量增大，蒸汽会优先从水平井跟端分配，跟端配汽量始终最多；当调整注汽井前、后配汽孔分布密度时，可有效改变水平井前、后的配汽量，并优化配汽效果。模拟实验可以为油田注汽井配汽结构优化设计提供理论支撑，以达到有效提高配汽效果和均匀动用储层的目的。     

Zincated Nanoclay Polymer Composites (ZNCPCs): Synthesis,Characterization, Biodegradation and Controlled Release Behaviour in Soil

Novel zincated nanoclay polymer composites (ZNCPCs) with variable percentage of commercial bentonite and nanobentonite (8%, 10% and 12% of monomer for each case) were synthesized. Polyacrylic acid-Polyacrylamide copolymer was synthesized using N, N-Methylene bisacrylamide as crosslinker and ammonium persulfate as initiator. Clays as well as ZNCPCs were characterized by XRD, SEM, TEM and FTIR. 12% nanoclay containing formulation showed slowest release rate. ZNCPCs containing 8% clay recorded highest Zn content as well as highest equilibrium water absorbency. Biodegradation study revealed that Aspergillus spp was more effective as compared with Trichoderma spp in degradation of ZNCPCs.     

Design of an aeronautic pitot probe with a redundant heating system incorporating phase change materials

The aim of this work is the design of a pitot probe (PP) prototype in order to retard the cool down of the tip, in case of a heating element failure. The viability of operation in flight conditions is evaluated. The design consists of a redundant heating system incorporating phase change materials (PCM). Combining experimental observations of ice formation with the implementation of the conjugate heat transfer (CHT) model, with the addition of the heat release due to the phase change of the PCM, the numerical evaluation is developed. The modelling assumptions and numerical implementation of the phase change process are presented. Then, the selection an appropriate PCM is based on the low flammability and volume dilation and the quantitative effects of the material properties on the heat transfer. A commercial PCM solution based on salt hydrates was chosen as the most adequate for the design. The parametric design of the prototype, based on the design of experiment method and fractional factorial testing, is established. A multiple linear regression model was obtained in order to maximize the cooling retardation. The numerical simulations demonstrate that the prototype PP tip temperature remains 194 s longer above 0 °C than that of the conventional model analyzed.     

数字电子技术实验“线上-线下混合”教学改革

在“移动互联网+课堂”的大势趋动下,针对现在“数字电子技术实验”教学存在的教学模式落后,教学手段单一,教学内容简单、以及考核不够全面等问题,借助超星泛雅 “一平三端”平台进行“线上-线下混合教学”改革。通过课前发布任务、课中有效组织课堂活动、课后发布作业、统计数据和教学反思进行。实践表明：该方法提高了学生的自主学习能力,并且增强了教师对学生学习情况的动态跟踪和过程性指导,同时也让课堂教学更有效,教学评价方式更有针对性、更精准,最终达到知识、技能和情感态度价值观的培养。     

Binary Ti–Fe system. Part I: Experimental investigation at high pressure

The present work illustrates the effect of quasi-hydrostatic pressure on the positions and widths of the homogeneity ranges of the intermetallic phases TiFe and TiFe₂ at high temperatures. The experiments were performed with Ti–Fe diffusion couples that were heat treated in a multi-anvil press at 2.5 GPa. The solubility limits of the phases were derived from the concentration profiles that were measured using electron probe microanalysis. It was found that the homogeneity ranges of TiFe and TiFe₂ extend to higher titanium concentrations, if the pressure is applied. The positions of the phase boundaries of the intermetallics on the iron-rich side are not affected by the pressure. The accuracy of the experimental data including the homogeneity ranges and temperatures was verified by comparing the homogeneity ranges of β-Ti(Fe), α/δ-Fe(Ti) and γ-Fe measured in this study with the homogeneity ranges taken from literature. The pressure was calibrated using the pressure-induced phase transitions of bismuth.     

Ag–Sr doped mesoporous bioactive glass nanoparticles loaded chitosan/gelatin coating for orthopedic implants

In this study, we investigated surface and biological properties of Ag–Sr-doped mesoporous bioactive glass nanoparticle (Ag–Sr MBGN) loaded chitosan/gelatin coatings deposited by electrophoretic deposition (EPD) on 316L stainless steel. The EPD parameters, that is, deposition time, applied voltage, and distance between the electrodes was optimized by the Taguchi design of experiment (DoE) approach. Scanning electron microscopy (SEM) images illustrated the spherical morphology of the synthesized Ag–Sr MBGNs with the mean particle size of 160 ± 20 nm. Energy-dispersive X-ray (EDX) spectroscopy results confirmed the presence of Ag and Sr in the synthesized MBGNs. Optimum EPD parameters determined by DoE approach were 5 g/L of Ag–Sr MBGNs, deposition time of 5 min, and applied voltage of 30 V. SEM images confirmed that the coatings were fairly homogenous. Fourier-transform infrared spectroscopy and EDX results confirmed the presence of chitosan, gelatin, and Ag–Sr MBGNs in the coatings. Chitosan/gelatin/Ag–Sr MBGN composite coatings exhibited suitable wettability for the protein attachment and proliferation of osteoblast cells. The composite coatings exhibited suitable adhesion strength with the substrate. The coatings developed HA crystals upon immersion in simulated body fluid. The results of the turbidity test confirmed that the coatings are antibacterial to the Escherichia coli cells.