顾及高效可视化的 CAD模型数据重组织方法 *

CAD模型造型精度高 ,渲染效果逼真 ,被广泛应用于虚拟现实、实时仿真以及三维地理信息系统等三维可视化中 ,但是其几何模型数据复杂 ,图像数据量大 ,也导致可视化效率低下。为此 ,提出了一种 CAD模型数据重组织方法 ,旨在解决当前可视化应用集成 CAD模型数据效率低下的问题。采用预先计算可视化信息 ,高度紧凑组织数据 ,顾及图形软硬件特性等一系列策略 ,实现 CAD模型数据的高效可视化功能。其中 ,几何模型绘制和图像纹理生成效率均提高了 10倍以上。该方法被成功应用于香港志莲净苑佛寺虚拟旅游演示项目中。     

基于随机森林算法的泥页岩孔隙度预测

准确、快速地获取泥页岩孔隙度对页岩油空间分布及勘探目标预测具有重要意义。针对利用测井响应方程预测孔隙度精度较低的问题,建立一种基于随机森林算法的孔隙度预测模型,与BP 神经网络、支持向量机和XGBoost 算法进行预测精度对比,并利用SHAP 方法分析测井参数的重要性和影响范围。研究结果表明：随机森林算法可以很好地预测泥页岩孔隙度,且预测效果好于BP 神经网络、支持向量机和XGBoost 算法;基于随机森林算法的泥页岩孔隙度预测在渤海湾盆地某凹陷应用发现,对模型预测孔隙度最重要的前3 项测井参数为补偿中子、自然伽马和普通视电阻率;基于随机森林算法的泥页岩孔隙度预测模型可以快速识别单井孔隙度,不仅可以弥补因无法连续取心而难以获取完整孔隙度分布特征的问题,还能大幅提高孔隙度预测效率与精度。     

普通稠油原位乳化降黏驱微观渗流特征可视化研究

普通稠油乳化降黏驱是表面活性剂驱和乳状液驱的综合过程,既包含表面活性剂的降低界面张力作用,又包含乳状液的调驱作用。为此,采用微观物理模拟可视化研究多孔介质中乳状液的形成机制和运移特征,利用天然露头长岩心并联驱替实验分别进行水驱+乳化降黏驱和直接乳化降黏驱实验,进一步验证乳化降黏驱渗流特征,对比分析乳化降黏驱的驱油效果。实验结果表明,乳化降黏驱在剪切和降低界面张力作用下原位形成乳状液,形成的乳状液通过卡封、架桥和吸附滞留3 种封堵模式导致驱替介质的频繁绕流改道,起到扩大波及范围及提高驱油效率的作用。乳状液运移过程中与多孔介质相互作用,呈三快三慢的渗流特征。由此导致的渗滤作用,使乳状液分布沿着渗流路径和驱替倍数增加呈规律性变化。对比不同注入方式的岩心并联驱替实验结果,发现直接乳化降黏 驱比水驱的启动压力低（分别为0.57 和1.52 MPa）,水驱后进行乳化降黏驱的注入压力由0.37 MPa 升至1.17 MPa。随着乳化降黏剂溶液的注入,驱替压力波动式上升直至平衡。相同注入量下,直接乳化降黏驱比水驱+乳化降黏的驱油效率增加了16.69%,进一步证实乳化降黏驱扩大波及范围和提高驱油效率的有效性。     

Kinetics simulation of propylene epoxidation over different Ti species in TS-1

A thorough experimental investigation on the kinetic behavior of liquid-phase propylene epoxidation over TS-1 and tetrapropylammonium hydroxide (TPAOH) treated TS-1 catalysts was conducted in a fixed-bed reactor. The amounts of different coordinated Ti species in the catalysts were quantified by spectroscopies, and their catalytic performances of the epoxidation and alcoholysis of propylene oxide were measured by kinetic modeling. The study shows that the TPAOH treatment converted some of the tetrahedrally coordinated Ti to octahedrally coordinated Ti, and both species were active for the epoxidation and alcoholysis. The superior catalytic performance observed over the TPAOH treated TS-1 is due to two factors, the increased percentage of active sites, and reduced energy barrier for epoxidation on the octahedrally coordinated Ti. In addition, as the H₂O₂ conversion increases, the adsorption equilibrium constant of propylene oxide plays a more decisive role than the activation energy for the selectivity of propylene glycol monomethyl ethers.     

Oxidation resistance and thermal stability of the SiC-ZrB2 composite ceramic fibers

In this study, continuous SiC-ZrB₂ composite ceramic fibers were synthesized from a novel pre-ceramic polymer of polyzirconocenecarbosilane (PZCS) via melt spinning, electron beam cross-linking, pyrolysis, and finally sintering at 1800°C under argon. The ZrB₂ particles with an average grain size of 30.7 nm were found to be uniformly dispersed in the SiC with a mean size of 59.7 nm, as calculated using the Scherrer equation. The polycrystalline fibers exhibit dense morphologies without any obvious holes or cracks. The tensile strength of the fibers was greater than 2.0 GPa, and their elastic modulus was ~380 GPa. After oxidation at 1200°C for 1 hour, the strength of the fibers did not decrease despite a small loss of elastic modulus. Compared to the advanced commercial SiC fibers of Tyranno SA, the fibers exhibited improved high-temperature creep resistance in the temperature range 1300-1500°C.     

Printability,shape-memory,and mechanical properties of PHB/PCL/CNFs composites

Shape-memory polymers have attracted attention as smart implant materials in recent years because they are lightweight, low-cost, easily processable, and because they undergo large deformation. Here, cellulose nanofibers (CNFs) were used as a reinforcement for polyhydroxybutyrate (PHB)/polycaprolactone (PCL) composites to improve mechanical properties. The composites were investigated by rheological tests, differential scanning calorimetry, dynamic mechanical analysis, mechanical property tests, and shape-memory tests. The printability of PHB/PCL/CNFs composites was demonstrated by using them to print interconnected porous structures with a gyroid surface. The results showed that the PHB/PCL (80:20) composites with 1 wt% CNF displayed the best comprehensive mechanical and shape-memory properties. As a functional verification, a model of the self-opening hand was fabricated by 3D printing, and its deformation and recovery capabilities were evaluated.     

Aramid fiber reinforced EPDM microcellular foams: Influence of the aramid fiber content on rheological behavior,mechanical properties,thermal properties,and cellular structure

In this paper, aramid fiber (AF)/ethylene-propylene-diene monomer (EPDM) microcellular foams added with different content of AF are prepared by the supercritical foaming method. The effect of the AF content on the rheological behavior, mechanical properties, thermal properties and cellular structure of the AF/EPDM microcellular foams has been systematically studied. The research illustrates that compared with pure EPDM, the AF/EPDM matrix has greater viscosity and modulus, which is conducive to reduce the cell size and increase its density. And the thermal stability of EPDM foams is improved with the addition of aramid fiber. Meanwhile, when the content of AF is added to 1 wt%, the AF/EPDM microcellular foam exhibits a relatively low thermal diffusion coefficient and apparent density with the thermal conductivity to 0.06 W/mK. When the AF is added to 5 wt%, the tensile strength of the AF/EPDM microcellular foam increases to 1.95 MPa, which is improved by 47% compared with that of the pure EPDM foam. Furthermore, when the compressive strain reaches to 50%, the compressive strength of the AF/EPDM microcellular foam is 0.48 MPa, improved by 296% compared with that of the pure EPDM foam.     

空调负荷二阶等效热参数模型参数辨识方法

空调负荷是最具潜力的需求侧资源之一.然而,由于建筑环境、用户偏好等因素的差异,空调负荷具有明显的异质性,脱离实际场景建立空调负荷异质性聚合模型,难以准确获取其聚合功率及响应潜力.在具体应用场景下,搭建了实际空调负荷集中控制系统,并在实际空调系统支持下,提出计及空调负荷二阶等效热参数模型参数时变特性的参数辨识方法.通过最小化二阶等效热参数模型仿真温度与实测温度误差,同时考虑参数的时变特性,建立优化模型,获得二阶等效热参数模型参数.算例结果表明,所提方法能够建立较为准确的空调负荷二阶等效热参数模型.     

AAO工艺+絮凝沉淀处理高COD废水

为解决某植物榨汁饮料厂的废水COD高、有异味等问题,研究了厌氧—缺氧—好氧(AAO)工艺和絮凝沉淀混合工艺对废水的处理效果。探索了初始浓度、曝气量、絮凝剂的种类和投加量等对废水处理效果的影响机制。实验结果表明,初始浓度为4000 mg/L的废水,经AAO工艺后COD去除率可达77%。继续投加合适的絮凝剂后废水COD去除率可达90%。处理后的废水澄清无异味,可进行后续处理排放。     

双轨制下中长期交易电量放开规模测算方法

随着中长期交易电量规模持续扩大,交易结果不断挤压系统可调度空间,威胁着系统安全运行,且大量交易结果可能由于电网运行约束被削减,容易引发市场成员对市场公平性的质疑.因此,探究中国计划电量与市场电量"双轨制"下的中长期交易电量放开规模,既有助于明确电力市场的演变态势,又有利于实现电网运行安全和经济效率的统筹优化.文中提出了中长期交易电量放开规模测算方法,该方法兼顾市场化电量出清优化与电网运行安全,构建一个考虑市场经济效益和电网运行约束的双层优化模型.上层为以社会福利最大为目标的市场化电量优化出清模型,下层为考虑输电线路传输容量、系统供热需求、机组检修安排、电厂最小开机方式等电网运行约束的市场化电量校核模型.针对该双层优化模型,提出上下层迭代算法进行求解,并将市场化电量执行约束松弛化处理,以保证模型的可解性.中国某省级电网的实际算例分析验证了所提模型与算法的有效性和实用性.