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关键词： abrasive water jet   liquid-solid flow   MATLAB   fluent   nozzle geometry  

摘要： In the field of abrasive-water-jet polishing technology, the influence of nozzle geometry on nozzle wear and internal-structure erosion in abrasive-water-jet polishing technology is studied, and the nozzle design is optimized through experiments and a numerical simulation to improve the stability and efficiency of the abrasive jet. The mathematical model between the cross-sectional area of the nozzle and the dimensionless length of the nozzle is established, as well as the variation in the static pressure of the nozzle and the length of the nozzle. Through Fluent simulation, it is found that when the nozzle length is 12 mm, the abrasive-phase acceleration is sufficient and the erosion intensity is minimal. After 480 h of erosion experiments, the erosion profile of nozzle cavity was detected. The results show that the erosion strength of the 12 mm nozzle is the least, followed by the 6 mm nozzle, and the 18 mm nozzle is the strongest, which is consistent with the simulation results.

关键词： Decoupling coefficient   MATLAB   damage variable   fractal dimension   damage prediction model  

摘要： To investigate damage range and damage degree of PMMA under different decoupling charge coefficients (K) after blasting, a reasonable range of decoupling coefficient was theoretically determined. Experimental images after blasting were obtained through two-dimensional (2D) model experiment. Algorithms for computing damage variables and fractal dimensions of cracks in different zones were developed in MATLAB software, and the relationship between fractal dimension and blasting damage was established. The results indicated that as the decoupling coefficient increased, the length of the longest primary crack and the total length of cracks decreased gradually. Damage variable (omega) of the decoupled charge blasting decayed exponentially with increasing distance, ultimately approaching zero. Meanwhile, the attenuation rate increased with increasing decoupling coefficient. The relative sizes of fractal dimensions based on the box-counting dimension algorithm correlated with the macroscopic damage variables. Fractal dimensions in the blasting zones I, II, and III decreased sequentially as the decoupling coefficient increased, resulting in an overall reduction in overall fractal dimension. A prediction model for blasting damage in PMMA material under model experiment conditions was established. The calculated blasting damage degree based on fractal dimension can be used to quantitatively evaluate the spatial distribution characteristics of blasting-induced cracks, which provides a new approach to study the evolution patterns of blasting damage of rocks.

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： 涟洼排干   河道   综合治理  

摘要： 为进一步改善生态环境,并促进沧州经济发展,需要综合治理渤海新区的水环境,其中涟洼排水河道作为主要的治理工程项目,其中所涉及到的综合治理工程技术至关重要.本文将针对于涟洼排水河道综合治理工程中的清表清淤、土方挖掘、土方填筑、混凝土以及绿化种植等众多施工技术要点加以研究分析,确保在涟洼排干河道的综合治理中取得良好的建设成果的同时,也能够为其他的相似河道工程提供施工参考.

关键词： MATLAB  

摘要： Lighting is an art and technology is its canvas. In modern interior architectural designs lighting systems have evolved beyond their primary function to integrate communication capabilities through Visible Light Communication (VLC). This work explores the dual role of LED (Light Emitting Diode) lighting in providing illumination and enabling data transmission. A number of lighting models have been analyzed such as flush mount lighting, recessed lighting, hanging pendant, chandeliers, slide rails, pendant light cluster, diagonal linear strips, linear strips across y-axis, random LED lighting patterns and wall fixture LEDs. Performance metrics such as illuminance levels, uniformity, ISO compliance, received power, signal-to-noise ratio (SNR) and mobility area coverage were analyzed to assess lighting efficiency and VLC data transmission quality. The work employs MATLAB and DIALux Evo software to simulate and analyze the performance of various lighting configurations. Additionally, four specific LED products 726.70 PANTALLA 4000 K, 726.80 PANTALLA 3000 K, ELIA PL M2 DALI and MOLNPRO 4400LM 840 MP were evaluated for their dual capabilities in illumination and Visible Light Communication (VLC). The work offers valuable insights into designing multifunctional, energy-efficient indoor environments that integrate advanced lighting and communication technologies.

关键词： 住宅建筑   混凝土浇筑   技术要点  

摘要： 随着城市化进程的加速,住宅房屋建筑工程的需求日益增长.混凝土浇筑作为建筑施工的核心环节,其施工质量直接关系到建筑物的结构安全和使用寿命.因此,明确混凝土浇筑施工中的技术要点,对于确保工程质量和提升建筑施工水平具有重要意义.因此,文章结合工程实例,对混凝土浇筑施工中的相关技术要点进行了探讨分析,以供参考.

摘要： 涡阳县日照充足、气温较高、雨量充沛,在夏玉米种植中具备良好的自然条件优势.在夏玉米栽培中,涡阳县应推广科学的栽培技术,从选种到收获的全过程各个阶段加强栽培管理,以保证实现玉米高产目标.