Results 81 to 90 of about 611 (152)
Key technologies and demonstration of unmanned steeply inclined short-wall fully mechanized top-coal caving intelligent mining [PDF]
Since the 14th Five-Year Plan, my China’s coal mine digital intelligence technology has developed rapidly, especially in thin coal seam mining. However, the unmanned intelligent mining technology of steeply inclined short-wall fully mechanized caving is ...
Bin GU +10 more
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Characteristics and prevention and control techniques of typical water hazards in coal mines in Shaanxi Province [PDF]
Shaanxi province is rich in coal resources and is one of the main coal-producing provinces in China, with a coal production of 746 million tons in 2022. Due to the obvious differences in geological and hydrogeological conditions in the coal mining areas ...
Chaofeng LI +7 more
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Xibei Gongye Daxue XuebaoFixed-wing unmanned aerial vehicles (UAVs) featured in long endurance and extended range, demonstrate notable advantages in performing wide-area surveillance missions over complex terrains such as plateau canyons.
Zhu Yue, Wang Rui, Zhou Zhou
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Current situation and development trend of mechanized shaft driving in frozen shaft [PDF]
In view of the energy occurrence structure of “rich coal, poor oil and little gas” in China, and the situation that coal will occupy the dominant position of energy consumption for a long time,The development history of frozen shaft mechanized drilling ...
Hang DING +6 more
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Zhendong Ceshi yu Zhenduan时变线性方程的快速求解在工程计算和机器人控制中具有重要意义，但现有零化神经网络通常面临收敛速度慢和对噪声敏感的问题。对此，提出了一种具有噪声抑制能力的预定义时间收敛的零化神经网络（predefined‑time convergent noise‑suppressing zeroing neural network，简称PTC‑NS‑ZNN）模型。首先，设计了一种基于模糊逻辑的参数调节机制，使激活函数可随误差变化自适应调整非线性增益，从而增强系统的瞬态性能并提高稳态精度；其次 ...
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China’s CBM exploration and production and associated technological advancements: A review and reflections [PDF]
Objective and Methods Based on extensive scientific and technical literature and technical data on coalbed methane (CBM) exploration and production projects, this study conducted a comparative analysis of the development process and latest advances in ...
Jianping YE
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Shiyou jixie, 2015 气体钻井中携岩气体冲击四通内壁是导致四通失效的主要原因。基于气固两相流和冲蚀理论，运用CFD软件对四通本体流体域进行数值计算，分别研究了实际钻井工况下钻杆偏心的情形和不同钻井工艺对四通本体的冲蚀规律。研究结果表明，随着偏心距的增大，岩屑的轴向速度逐渐增大，局部冲蚀速率也呈现增大的趋势；由于偏心造成的岩屑粒子轨迹偏转向四通宽流道一侧冲击，容易在局部造成严重的冲蚀缺陷，导致四通承压能力下降；在不同钻井工艺下，冲蚀速率峰值和流体速度峰值都随注气量和岩屑质量流量的增加而基本呈线性递增趋势，而与岩屑粒径成反比关系，
邹 +7 more
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, 2016 通过对机器人的运动轨迹准确跟踪控制,能够有效提高机器人路径规划和自主定位的准确性。机器人在运动过程中运动轨迹受到小扰动分段线性误差的影响,机器人系统是一个多变量非线性系统,传统的遗传算法进行运动轨迹跟踪控制在边界层出现稳态跟踪误差。针对以上问题提出一种基于改进遗传算法的机器人运动轨迹跟踪控制算法。模拟构建所研究的机器人的运动环境模型,把机器人运动轨迹的空间坐标抽象为遗传种群的虚拟世界,得到机器人运动空间的网格结构模型。通过遗传进化的方式寻找目标点并进行移动 ...
刘一扬, 刘明明
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Zhendong Ceshi yu Zhenduan针对人字齿轮系统运行中普遍存在的非线性振动与分岔问题，首先，笔者基于集中参数法，构建融合拓扑修形效应、时变啮合刚度与齿侧间隙影响的24自由度弯⁃扭⁃轴⁃摆耦合动力学模型；其次，基于势能法精确建立含拓扑修形的人字齿轮时变啮合刚度模型，揭示修形对啮合刚度演化规律的深层机制；最后，采用龙格库塔法求解方程，结合分岔图、时域响应、频域特性、相平面轨迹及庞加莱截面，深入分析拓扑修形对系统分岔演化与混沌特性的影响。结果表明：拓扑修形后，系统振动与分岔特性的基本演化规律保持一致，局部分岔行为和振动响应得到有效改善 ...
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Zhongguo cuzhong zazhi目的 基于多组学数据解析动脉粥样硬化型缺血性卒中的免疫特征。 方法 通过孟德尔随机化联合转录组数据筛选动脉粥样硬化型缺血性卒中的相关基因。采用基因富集分析（gene set enrichment analysis，GSEA）和基因集变异分析（gene set variation analysis，GSVA）解析基因和通路功能。通过基因/蛋白质相互作用检索工具（search tool for the retrieval of interacting genes/proteins，STRING ...
迟骋，华实，车峰远（CHI Cheng, HUA Shi, CHE Fengyuan）
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