大采高综放工作面强动压端头顶板控制技术

为了解决大采高综放工作面回风侧端头顶板控制问题,针对马道头矿8211工作面的地质情况,通过对回风顺槽超前注浆加固,提高超前支护范围和支护强度,并对回风侧端头三角区煤壁和顶板进行化学浆加固的技术方案,有效控制了顺槽超前区围岩变形和工作面回风侧端头三角区煤壁片帮,保证了工作面端头区顶板安全。     

氧化石墨烯改性碳纤维复合材料抗冲击行为研究

使用单层纳米氧化石墨烯（NGO）粒子对环氧树脂进行改性处理，采用真空辅助树脂传递模塑成型工艺制备了[±45/0/90]_2S铺层角度下的纯树脂及单层NGO改性碳纤维复合材料（CFRP）层合板。通过落锤冲击试验、超声C扫描检测、冲击后压缩试验等对纯树脂及单层NGO改性CFRP进行实验研究。结果表明，纯树脂及单层NGO改性CFRP在损伤阻抗及损伤容限实验中均存在拐点现象，且拐点出现在相同深度位置，其中纯树脂CFRP拐点位置为0.51 mm，单层NGO改性CFRP拐点位置为0.43 mm；相对于纯树脂CFRP，单层NGO改性CFRP可以显著提高复合材料的抗冲击性能及冲击后的压缩性能；通过对冲击后凹坑深度及凹坑面积进行数据模拟，可以用拟合公式实现对复合材料的损伤预测。     

Microstructure evolution and cooperative reinforcement mechanisms of Al2O3/Al2O3 joints brazed by low-melting borosilicate glass

The Al₂O₃/SiO₂–B₂O₃–Al₂O₃–Na₂O glass/Al₂O₃ joints reinforced cooperatively by glass matrix and in-situ Al₄B₂O₉ whiskers were obtained via a low-melting borosilicate glass braze. The composition of glass seam transformed from SiO₂–B₂O₃–Na₂O to SiO₂–B₂O₃–Al₂O₃–Na₂O due to continuous diffusion and dissolution of Al₂O₃. An appropriate amount of [AlO₄] units introduced into the glass braze played a vital role in strengthening the glass network structure resulting to considerably improved mechanical strength of the glass seam. Meanwhile, plenty of in-situ Al₄B₂O₉ whiskers growing from the Al₂O₃/glass braze interface to the center of glass seam in various directions generated. Three-dimensional crisscross structures were fabricated at the Al₂O₃/glass braze interface domains, where were enhanced by crack-bridging and pull-out effect of the whiskers. Generally, ascribed to the cooperative reinforcement of the glass matrix in the seam and in-situ Al₄B₂O₉ whiskers at Al₂O₃/glass braze interface domains through reactions of Al₂O₃ and borosilicate glass braze, strength of the as-brazed joints was promoted prominently. The shear strength of the joints reached a maximum of 61 MPa brazed at 1050 °C for 60 min.     

A Novel Beam Search to Improve Neural Machine Translation for English-Chinese

Neural Machine Translation (NMT) is an end-to-end learning approach for automated translation, overcoming the weaknesses of conventional phrase-based translation systems. Although NMT based systems have gained their popularity in commercial translation applications, there is still plenty of room for improvement. Being the most popular search algorithm in NMT, beam search is vital to the translation result. However, traditional beam search can produce duplicate or missing translation due to its target sequence selection strategy. Aiming to alleviate this problem, this paper proposed neural machine translation improvements based on a novel beam search evaluation function. And we use reinforcement learning to train a translation evaluation system to select better candidate words for generating translations. In the experiments, we conducted extensive experiments to evaluate our methods. CASIA corpus and the 1,000,000 pairs of bilingual corpora of NiuTrans are used in our experiments. The experiment results prove that the proposed methods can effectively improve the English to Chinese translation quality.     

掘进巷道快速过断层施工技术应用

基于四候煤矿3108回风顺槽过F3断层期间,顶板出现严重破碎、下沉现象,提出了俯斜台阶法施工工艺,并对断层破碎带顶板采取MF-2型化学材料注浆加固以及"钢筋锚索网+U29梯形棚"联合支护措施。支护效果检验结果表明,联合支护有效控制了断层破碎区顶板下沉、破碎现象,保证了巷道顶板稳定性。     

Fatigue behaviour of composite–composite joints reinforced with cold metal transfer welded pins

In this paper the fatigue properties of through-the-thickness reinforced joints are studied in detail. Unreinforced specimens, specimens reinforced with cold metal transfer welded titanium and steel pins and specimens reinforced with titanium z-pins are investigated. Besides classical S–N diagrams, hysteresis curves and stiffness based approaches are applied to improve the understanding of the mechanical behaviour of the joints in the progress of their fatigue life. Furthermore full field strain analysis gives information about damage initiation and growth in the joint section.     

Assessment of the effectiveness of steel fibre reinforcement for the punching resistance of flat slabs by experimental research and design approach

The present paper deals with the experimental assessment of the effectiveness of steel fibre reinforcement in terms of punching resistance of centrically loaded flat slabs, and to the development of an analytical model capable of predicting the punching behaviour of this type of structures. For this purpose, eight slabs of 2550 × 2550 × 150 mm³ dimensions were tested up to failure, by investigating the influence of the content of steel fibres (0, 60, 75 and 90 kg/m³) and concrete strength class (50 and 70 MPa). Two reference slabs without fibre reinforcement, one for each concrete strength class, and one slab for each fibre content and each strength class compose the experimental program. All slabs were flexurally reinforced with a grid of ribbed steel bars in a percentage to assure punching failure mode for the reference slabs. Hooked ends steel fibres provided the unique shear reinforcement. The results have revealed that steel fibres are very effective in converting brittle punching failure into ductile flexural failure, by increasing both the ultimate load and deflection, as long as adequate fibre reinforcement is assured. An analytical model was developed based on the most recent concepts proposed by the fib Mode Code 2010 for predicting the punching resistance of flat slabs and for the characterization of the behaviour of fibre reinforced concrete. The most refined version of this model was capable of predicting the punching resistance of the tested slabs with excellent accuracy and coefficient of variation of about 5%.     

Influence of the tufting yarns on formability of tufted 3-Dimensional composite reinforcement

In aerospace industry, thicker and more complex composite parts are needed. Multilayered reinforcement is largely used as the traditional method. Recently, three-dimensional (3D) fabrics are developed to replace the multilayered reinforcements in certain applications to increase the performance in thickness direction of part, e.g. interlock structure. Currently, the development of tufting technology can be employed to produce the 3D textile composite reinforcements. The tufting parameters, such as tufting density, tufting length and tufting yarn orientations, can be completely controlled by user. In order to improve the understanding of formability of the tufted 3D fabric during manufacturing, the present work analyzes the preforming behaviours of tufted 3D reinforcement in the hemispherical stamping process. Also the preforming behaviours are compared with the samples of the multilayered forming. The experimental data demonstrated the influence of tufting yarns on the material draw-in, interply sliding, and winkling phenomenon during forming. Furthermore, the orientations of tufting yarn affected the forming results, which leaded to misalignment defect in the zone of strong in-plane shear.     

Cylindrical conformal single-patch microstrip antennas based on three dimensional woven glass fiber/epoxy resin composites

Three dimensional integrated microstrip antenna (3DIMA) can carry the designed load while functioning as an antenna. In this study, the cylindrical conformal single-patch 3DIMAs with various curvatures were designed, simulated, fabricated and tested experimentally using a 3D orthogonal woven glass preform/epoxy resin composite system. The electromagnetic performances of the cylindrical microstrip antennas were analyzed. The simulated and tested results matched well and the return losses of the cylindrical conformal 3DIMAs with radii of curvatures of 60, 45 and 25 mm were less than −10 dB while resonant frequencies and their gain values were significantly influenced by the radius of curvature and the feeding direction. The 3DIMAs with the curvature perpendicular to the feeding directions showed more stable resonant frequencies and larger gain values than those of 3DIMAs with the curvature along their feeding directions.     

基于Q-learning的不确定环境BDI Agent最优策略规划研究

BDI模型能够很好地解决在特定环境下的Agent的推理和决策问题,但在动态和不确定环境下缺少决策和学习的能力。强化学习解决了Agent在未知环境下的决策问题,却缺少BDI模型中的规则描述和逻辑推理。针对BDI在未知和动态环境下的策略规划问题,提出基于强化学习Q-learning算法来实现BDI Agent学习和规划的方法,并针对BDI的实现模型ASL的决策机制做出了改进,最后在ASL的仿真平台Jason上建立了迷宫的仿真,仿真实验表明,在加入Q-learning学习机制后的新的ASL系统中,Agent在不确定环境下依然可以完成任务。