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关键词： 船舶安全   船舶避碰   旋回圈   紧迫局面距离   碰撞距离   会遇态势  

摘要： 为解决近距离船舶避碰行动的关键问题,研究船舶碰撞会遇过程中转向避让过程,结合船舶的操纵性能,对船舶初始旋回半圆要素以及旋回角度的时间特性进行分析;通过相对运动图的分解和逆向逼近算法,得到船舶转向避让时紧迫局面距离和碰撞距离的数学模型,并且给出该模型的应用;模型应用的结果通过算例和模拟试验得到验证.研究结果表明:提出的两个距离模型可用来指导近距离时船舶避碰行动,为研究船舶碰撞危险度和建立船舶自动避碰决策系统提供理论依据.同时,根据该模型,分析对于不同船速比和不同方位的目标船,存在碰撞危险时,本船在不同的会遇阶段应该采取相应的避碰行动,也给出了近距离船舶避碰行动模式.为船舶驾驶员提供近距离船舶碰撞危险预测和船舶避碰决策支持.研究成果对船舶航行安全和航行智能化具有重要意义.

关键词： Predictive control systems  

摘要： With the rapid development of automotive active safety technology，the chassis electronic control unit of modern electric vehicles has seen explosive growth. In order to improve the real-time performance and accuracy of chassis active safety control，for the rapid growth of chassis electronic control units and the coupling conflict problems of low integration degree of control system and multi-objective co-optimization，in this paper firstly a chassis system integration control architecture based on multi-agent is established，and a hierarchical control system integrating the front and rear wheels' active steering system and the differential braking control system is proposed. Secondly，based on this，the state equations of each agent and its contribution to the vehicle's center of mass model are established and combined with the model predictive control to consider the characteristics of constraints. The cost function containing global state tracking error and local control effort is designed considering both the actuator constraints and the ground friction ellipse constraints. Finally，each agent realizes its collaborative control through the interaction of dynamic information of its respective contribution. The results show that the vehicle stability control method based on multi-agent model prediction proposed in this paper has obvious improvement in terms of traverse stability compared with independent control of each active safety unit under the driving conditions of high and low road attachment and large curvature curves，which has certain value for engineering application. © 2025 SAE-China. All rights reserved.

关键词： Magnetic levitation vehicles  

摘要： Rich-nickel layered ternary NCM811 has been widely used in the field of electric vehicles ascribed to its high theoretical specific capacity. However, poor cycling stability and rate-performance hindered its further development. Herein, different amounts of nitrogen-doped carbon were wrapped on the surface of NCM811 via a facile rheological phase method by regulating the amount of dopamine hydrochloride. The effects of the coating amounts on the structure and electrochemical performance are investigated. The DFT calculation, XRD, SEM and XPS reveal that an appropriate amount of nitrogen-doped carbon coating could uniformly form a protective layer on the NCM811 surface and the introduced N could anchor Ni atoms to inhibit the Li+/Ni2+ mixing, but excessive amount would reduce Ni3+ to Ni2+ so as to conversely aggravate Li+/Ni2+ mixing. Among the samples, the NCM811-CN0.75 sample exhibits the most excellent electrochemical performance, delivering a high-rate capacity of 151.6 mA·h/g at 10C, and long-term cyclability with 82.2% capacity retention after 300 cycles at 5C, exhibiting remarkable rate-performance and cyclability.

关键词： 构造地质   薄煤层   构造定量评价   构造曲率   趋势面分析   煤厚变异系数   稳定性   精准开采  

摘要： 薄煤层条件下的煤炭开采对精确掌握煤厚与构造的空间变化规律提出了更高要求。陕西延安黄陵矿区北部发育薄煤层，对其构造发育特点与煤厚空间变化规律认识不清，限制了煤炭高效开采与智能化矿井建设。笔者以延安芦村二号煤矿主采的2号煤层为研究对象，基于煤层底板标高数据，开展趋势面分析与构造曲率分析，揭示构造展布与发育特点;基于网格剖分法计算了775个网格节点的煤厚变异系数，揭示煤层厚度及其稳定性变化规律，克服了传统煤厚变异系数单一评价值对揭示煤厚稳定性空间变化的不足。结果显示，芦村二号煤矿2号煤层属于较稳定煤层，整体呈一走向NE、倾向NW的单斜构造，在此背景下，叠加了轴向为NW的次级波状起伏。新识别并圈定了3处典型构造，分别为：煤矿东北部发育一局部凹陷，中北部发育一局部凸起，煤矿南部发育一个呈NW—SE向展布的马鞍状构造。在马鞍状构造北部叠加了勘探与采掘期间发现的若干断层，使得煤矿南部构造相对复杂。煤厚变异系数介于0.16%～15.24%，平均为1.98%，呈现从北向南逐渐增加的趋势，在西南部12-7和12-8号钻孔附近达到最大值。在可采范围内，煤层厚度稳定性由NE向SW逐步变差，马鞍状构造与煤厚变异系数高值区高度吻合。基于煤厚及煤厚变异系数分级，识别出6类煤厚及稳定性组合方案，实现了煤厚及稳定性的平面分区评价，揭示可采范围内东部的开采条件好于西部，西南部最差，源于马鞍状构造加剧了煤厚变化。研究成果可为薄煤层安全、高效、精准开采提供地质保障。

关键词： Cracks  

摘要： In existing studies, most slope stability analyses concentrate on conditions with constant temperature, assuming the slope is intact, and employ the Mohr-Coulomb (M-C) failure criterion for saturated soil to characterize the strength of the backfill. However, the actual working temperature of slopes varies, and natural phenomena such as rainfall and groundwater infiltration commonly result in unsaturated soil conditions, with cracks typically present in cohesive slopes. This study introduces a novel approach for assessing the stability of unsaturated soil stepped slopes under varying temperatures, incorporating the effects of open and vertical cracks. Utilizing the kinematic approach and gravity increase method, we developed a three-dimensional (3D) rotational wedge failure mechanism to simulate slope collapse, enhancing the traditional two-dimensional analyses. We integrated temperature-dependent functions and nonlinear shear strength equations to evaluate the impact of temperature on four typical unsaturated soil types. A particle swarm optimization algorithm was employed to calculate the safety factor, ensuring our method’s accuracy by comparing it with existing studies. The results indicate that considering 3D effects yields a higher safety factor, while cracks reduce slope stability. Each unsaturated soil exhibits a distinctive temperature response curve, highlighting the importance of understanding soil types in the design phase.

关键词： 晶界工程   微合金   纯铜   电导率   热稳定性  

摘要： 利用晶界工程对Cu-Ti-S微合金化纯铜组织结构进行调控,并结合电子背散射衍射(EBSD)和光学显微镜(OM)分析了晶界工程处理对导电性和热稳定性的影响与作用机理.结果表明,晶界工程处理(每道次工艺为:冷轧20%→再结晶退火530℃×10 min→水冷,循环4道次)可显著提高微合金化纯铜的晶粒尺寸热稳定性,并保持高导电性能.经0道次和4道次晶界工程处理试样的电导率分别为58.66、58.89 MS/m,在900℃×30 min高温加热后的晶粒尺寸分别为129.52、50.76 μm,有效抑制了晶粒长大.这主要与晶界工程处理增加了Σ3n CSL晶界比例有关,特别是Σ3 CSL晶界比例,具有低的晶界能量和迁移率.

关键词： 复合边坡   端帮开采   逆倾   稳定性   变形机制  

摘要： 端帮开采作为一种新型开采端帮压煤的方法,为探究其对高陡逆倾复合边坡变形的影响,以某露天矿为工程背景,分析了端帮开采后煤柱群、坡体变形破坏特征,结果表明:端帮煤开采后,重力非线性分布与两边简支、一边固支的边界条件改变了复合边坡的应力变形特征,端帮变形以水平方向为主,排土场变形以沉降为主.沿倾向,煤柱竖向位移与应力曲线先缓后陡变化,中心靠近煤壁侧,水平位移逐渐衰减,塑性破坏程度减小;沿走向,煤柱群变形呈马鞍形,永久煤柱边缘受剪切作用变形成拱形分布,单一采硐及煤柱群上方形成了稳定的岩体结构,顶板应力成拱形分布,塑性区由中心向两侧扩展.复合边坡变形分为剧烈变形区、缓慢变形区、稳定区,坡体前缘变形由与坡面平行转变为斜交,采硐顶板由圆弧剪出滑动变为沉降,变形破坏模式由重力引起的圆弧形滑移转变为煤柱破坏后沉降引起的大范围折线形滑动.由此得出结论:端帮开采使复合边坡变形以沉降为主,在排土场、端帮分区分布,加剧了开采区域坡体的变形,煤柱变形是复合边坡稳定的关键,应力、变形与采深为非线性关系,为非对称分布,破坏程度减小,竖向应力与位移峰值点靠近工作面,水平位移非线性减小,复合边坡的先陡后缓结构与煤层逆倾特征导致的坡体重力非线性分布、端帮开采造成的边界条件差异是煤柱与边坡变形破坏的主要原因.

关键词： 煤矿地下水库   煤柱坝体   稳定性评价   评价模型   防控措施  

摘要： 我国西部矿区生态环境脆弱,水资源极其匮乏,已成为制约我国煤炭工业科学发展的关键因素.煤矿地下水库是西部矿区煤炭开采水资源保护与利用的重要技术手段,其安全运行已成为矿区保护利用矿井水资源的关键,而煤柱坝体的稳定性是保障煤矿地下水库安全运行的核心.因此,本文基于理论研究提出了煤矿地下水库煤柱坝体稳定性评价方法,构建了煤矿地下水库煤柱坝体稳定性评价模型,并以神东矿区石圪台煤矿地下水库为背景,对石圪台煤矿地下水库煤柱坝体稳定性进行了评价.提出了基于层次分析-模糊理论的煤矿地下水库煤柱坝体稳定性综合评价方法,建立了 4个准则层 14个指标层的煤矿地下水库煤柱坝体稳定性评价指标体系,4个准则层评价指标分别是坝体参数、水浸作用、煤层赋存条件、采动影响,14个指标层评价指标分别为坝体宽度、坝体高度、阻水能力、坝体强度、水质条件、水头高度、渗漏情况、储水时间、煤层倾角、煤层埋深、煤岩性质,生产扰动、下煤层采动距离、采空区结构形状;给出了各评价指标分级标准,建立了梯形分布的隶属函数,确定了各评价指标隶属度;基于专家打分构建了评价指标判断矩阵,得出了各评价指标的权重;由此评价了石圪台煤矿地下水库煤柱坝体稳定性,结果为较稳定.并对存在的不足提出了针对性的防控措施,建议近期对渗漏点开展注浆防渗加固,中远期加强煤柱坝体监测,未来规划煤矿地下水库时加大煤柱坝体留设宽度.

关键词： 伪S-渐近ω-周期函数   温和解   中立型偏微分方程  

摘要： 本文研究了Banach空间中抽象中立型偏微分方程伪S-渐近ω-周期温和解的存在性.利用Banach压缩映射原理,得到了该类方程伪S-渐近ω-周期温和解的存在性和唯一性.推广了中立型偏微分方程周期温和解的相关结论.