一种可传输轨道角动量的螺旋光子晶体光纤北大核心

设计了一种基于阿基米德螺线的新型螺旋光子晶体光纤,该光纤以二氧化硅为基底材料,包层由24个螺旋臂组成,每个螺旋臂包含11个小空气孔,纤芯设有大空气孔,包层与纤芯中间的环形区域用于传输轨道角动量模式。该结构在1300~1800 nm波段上可支持22种轨道角动量模式稳定传输,在1550 nm波长下,有效折射率差最高可达2.89×10^(-3),色散系数最低可达66.4 ps/(nm·km),非线性系数最低可达2.17 W^(-1)·km^(-1),且1500~1600 nm波段上的色散值变化均小于15.15 ps/(nm·km)。此螺旋光子晶体光纤不仅结构简单,且具有低非线性、色散平坦的性能,为螺旋光子晶体光纤的设计提供了思路。     

A finite line source simulation model for geothermal systems with series- and parallel-connected boreholes and independent fluid loops

A model for the simulation of geothermal systems with parallel- and series-connected boreholes is presented. Mass and heat balance problems are formulated for each component in the system and are assembled into system-level problems. A third problem is formulated to account for heat transfer in the bore field, using the finite line source solution. This third problem is coupled to the system-level heat balance problem by an analytical solution of the heat transfer inside boreholes with multiple U-tubes. The simulation model allows for any number of independent fluid loops within the bore field or within individual boreholes and allows for combinations of specified inlet fluid temperatures and heat extraction rates in independent fluid loops. The model accounts for the axial variation of the fluid and borehole wall temperatures and heat extraction rates. The capabilities of the model are demonstrated through three example simulations.     

露天爆破智能设计系统开发及应用

为了提高露天台阶爆破设计的规范化、便捷性，对露天台阶爆破设计系统进行了开发研究。以Visual C++为开发平台，软件采用MFC框架，结合OpenGL三维引擎开发技术，实现软件从底层自主开发生态的建立。通过现场工程实践应用表明爆破设计人员可以轻松通过本系统实现三维环境下的布孔设计和爆破网络设计以及精确的GPS布孔，并取得了良好的爆破效果，提高了台阶爆破的设计质量和设计速度。爆破智能设计系统能够实现矿山爆破设计的数字化、科学化、自动化和高效化，对于露天爆破具有十分重要的意义。     

基于遗传算法及仿真技术的服装生产流水线平衡

针对大部分服装企业存在生产流水线编制效率较低以及生产周期长的普遍现象,提出一种服装工序编排方案自动生成和单件流生产线仿真运行的方法。首先分析服装生产工序编排方法和影响因素,采用拓扑方法和遗传算法相结合,在MatLab(R2016b)软件中建立自动优化模型,实现工序的自动编排;然后考虑服装生产数量和生产线设备情况,采用仿真技术,在Plant Simulation仿真软件中,根据实际生产对工序编排方案进行流水线仿真运行,得出直观可视的仿真结果,实现流水线平衡再优化。生产实例验证表明,流水线编制效率为90.8%,比原有效率提高12.8%,节省流水线编排方案在投产前的平衡调试时间,生产周期缩短。     

曙光煤矿1226综采工作面瓦斯抽采技术

采用综合应用理论分析、现场实测的方法,对山西汾西集团曙光煤矿1226高瓦斯综采工作面瓦斯来源进行了分析,提出并实施了分区段“风排+煤层钻孔抽放+裂隙带钻孔抽放”的联合瓦斯抽采技术。现场监测结果显示:1226综采工作面上隅角瓦斯浓度控制在0.45%~0.75%,回风流中瓦斯浓度控制在了0.44%~0.75%,瓦斯治理效果明显改善。     

排列方式及电极距对高密度电法探测孤石的影响分析

通过高密度电法在广州某地铁线路勘察孤石的探测试验,分析几种不同排列方式及电极距对孤石高密度电法探测效果的影响,同电极距时,偶极装置具较高精度,对浅部不均匀体反映也较灵敏。满足探测深度条件下,缩小电极距时,微分装置相比偶极和温纳装置其探测精度效果更明显。试验表明β和γ装置测量数据的T比值参数法具有较好的探测效果,在实际工作中值得进一步试验推广。     

An experimental study to validate optimum distance between metal hydride tanks with staggered arrangement for effective thermal management

Thermal control is crucial in enhancing the life cycle of metal hydride tanks, which necessitates considering several critical parameters. In addition, a suitable arrangement of a metal hydride bank plays a significant role in transferring the heat efficiently. We have already studied the existence of an optimal distance in theory and proved that the maximized heat transfer rate is a function of the geometric arrangement. In this study, which is the second step of our previous work, we aim to experimentally validate the possible ideal distance in optimized metal hydride array by taking into account the results of our previous study. The experiments are carried out at a triple metal hydride bank with a forced convection system and the effects of optimum distance on the heat transfer performance of the metal hydride bank are analyzed with the staggered arrays in order to validate the results of numerical calculations for staggered metal hydride bank with the pitch-to-diameter ratio of 0.06 and 0.07 at the Reynolds number of 6000 and 12,000, respectively. The results obtained at the end of the experiments are as follows; i) metal hydride storage tanks are strongly affected by the array geometry for maximum heat transfer, especially for small pitch arrays at high Reynolds numbers; ii) the experimental findings are compared with the theoretical models and validated; iii) the overall efficiency of fuel cell-metal hydride system could potentially be increased by simple geometrical arrangements.     

厚煤层错层位巷道布置采全厚采煤法的研究

为提高煤炭资源采出率与综合解决厚煤层全高开采的技术难题,依据理论研究与生产实际,用新的理念提出了一种厚煤层无煤柱开采的错层位巷道布置采全厚采煤法,该方法已经应用于煤层倾角0～25°,煤质松软或中硬,自然发火期3～6个月以上的条件,安全生产1a多.使用该方法能够提高煤炭采出率10%以上,提高巷道掘进速度1倍以上,降低掘进成本30%.