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关键词： Mathematical chemistry   QSPR analysis   Random forest regression   Topological indices   Xgboost regression  

摘要： In this study, a quantitative structure–property relationship (QSPR) framework is presented that combines simple degree-based topological descriptors with ensemble machine learning methods to examine selected physicochemical properties of coronary artery disease (CAD) and cardiovascular therapy drugs. A data set of 100 clinically used compounds was considered, for which six classical degree-based indices, the Atom Bond Connectivity $\left(ABC\right)$, Atom-Bond Sum Connectivity $\left(ABS\right)$, Sum Connectivity $\left(SC\right)$, Harmonic $\left(H\right)$, Randić $\left(R\right)$, and Geometric–Arithmetic $\left(GA\right)$ were computed, and compared to four key properties: topological polar surface area ($tPSA$), calculated lipophilicity ($CLogP$), calculated molar refractivity ($CMR$), and aqueous solubility (

来源 ScienceDirectJournal 详细信息

关键词： PBL教学模式   工程制图与CAD”课程教学   制药工程专业  

摘要： 文章首先分析了“工程制图与CAD”课程教学现状,然后论述了基于PBL教学模式的“工程制图与CAD”课程教学改革,最后评估了基于PBL教学模式的“工程制图与CAD”课程教学改革成效。

关键词： ConvNeXt–MaxViT fusion   KOA severity grading   Radiographic deep learning   Transformer–CNN hybrid   Mid–late fusion   Grad-CAM++ explainability  

摘要： Knee Osteoarthritis (KOA) is a progressive degenerative joint disorder and a major cause of disability worldwide. Radiographic grading using the Kellgren–Lawrence (KL) scale remains the standard diagnostic method, but inherent subjectivity and difficulty in detecting subtle structural changes reduce diagnostic reliability. Thus, an automated, robust, and explainable system is clinically essential.

关键词： CAM   Eddy covariance   COS   Stomatal conductance   Transpiration   Flux measurements   Ecosystem scale  

摘要： Crassulacean acid metabolism (CAM) helps plants in arid regions to reduce water loss by opening their stomata and taking up carbon dioxide (CO${}_2$) during nighttime. While gas exchange in CAM plants has been mainly studied under controlled laboratory conditions, only a few ecosystem scale studies exist. Moreover, carbonyl sulfide (COS) has been used as a tracer for stomatal conductance, transpiration and photosynthesis in C${}_3$ and C${}_4$ plants, but no studies on CAM ecosystems have yet been published. Here we present the first ecosystem scale measurements of COS fluxes over Agave sisalana (CAM plant), commercially cultivated for its fiber. The measurements were made during the wet season in Kenya. The ecosystem was a consistent sink of COS, with higher uptake observed during nighttime (−11.5 pmol m⁻² s⁻¹) than during daytime (-5.6 pmol m⁻² s⁻¹). The magnitude of COS fluxes was comparable to non-growing season daytime fluxes reported for C${}_3$ and C${}_4$ plant dominated ecosystems. The soil was a small COS source (0.3 pmol m⁻² s⁻¹), with highest emissions under high radiation and temperature conditions. Using random forest modeling, we found that vapor pressure deficit, air temperature and soil water content were the most important drivers of nighttime ecosystem COS exchange (variable

关键词： 废旧涤纶纺织品   乙二醇醇解   对苯二甲酸乙二醇酯(BHET)   再生涤纶   绿色循环  

摘要： 针对废旧涤纶纺织品因成分复杂、含染料等导致回收产物品质低的问题, 本研究基于染料与纤维在乙二醇中的溶解性差异, 开发废旧涤纶纺织品乙二醇萃取脱色技术. 废旧涤氨混纺纺织品脱色率达99.8%, 实现涤氨纤维与染料的高效分离. 将脱色后涤氨纺织品进一步乙二醇醇解. 基于醇解产物对苯二甲酸乙二醇酯(BHET)相变特性开发减压相变纯化技术, 纯化单体rBHET的纯度达98.2%, 色度值L*=99.7、a*=^(−1).5、b*=0.1. 以rBHET缩聚制得再生涤纶(rPET), 经熔纺牵伸处理成功获得再生涤纶. 其特性黏度为0.692 dL g^(−1)、端羧基含量为16.1 mol t^(−1)、熔点为254 °C, 各项性能均达到纤维级聚酯切片标准. 再生涤纶品质(色度值、力学性能等)与石油基涤纶相当, 充分证明该回收路线的可行性及工业化潜力, 为涤纶全生命周期绿色循环利用提供理论参考.

关键词： 窄间隙焊接技术   TC4钛合金   热循环   显微组织   力学性能  

摘要： 热循环对钛合金厚板窄间隙焊接接头的组织和性能具有重要影响,本工作采用摆动送丝磁控电弧窄间隙焊接技术完成60 mm厚TC4钛合金焊接接头,借助数值模拟研究了典型热循环下的显微组织演变(α相、β相和晶界α_(GB))、显微硬度变化及拉伸性能变化。结果表明,高温热循环发生完全的α→β转变,将有利于α相择优生长,形成粗大且方向一致的α群落;相比之下,后续低温热循环发生不完全α→β转变,较低的冷却速率及温度梯度将削弱择优取向,板条α相得以细化。经过整个热循环后,板条α相的厚度由0.91±0.09μm增加至1.02±0.18μm,残余β相比例由0.02%增加至1.89%。得益于细晶强化作用,焊接接头打底层显微硬度最高;打底层拉伸强度最高,盖面层延伸率最高,接头均表现为韧性断裂。

关键词： CAD model reconstruction   Lattice structures   Planar convex hulls   Point cloud   Primitive detection  

摘要： Lattice structures consist of spatially discrete bars interconnected by joints. The complex geometric configurations of these lightweight structures present a challenge for point cloud segmentation, which is essential for CAD model reconstruction. We propose an efficient and robust pipeline to reconstruct CAD models of lattice structures from point clouds. The point cloud is first fitted by a set of planar convex hulls, which are optimized by local geometric operators guided by an energy function. The edges of discrete convex hulls are stored in an AABB tree for efficient hull adjacency queries. The convex hulls are then segmented based on their consistently oriented normals. Structural primitives are classified using principal component analysis of these oriented normals, and their dimensions are determined with least squares fitting of the associated points. The final CAD model is assembled from the detected primitives. The method has been validated using point clouds of various scales and complexities including real-scanned data. It shows robustness in the presence of uniform noise, outliers and data loss. Furthermore, its advantages in terms of reconstruction accuracy and efficiency are further highlighted in comparison to conventional and deep learning approaches.

关键词： 锌离子电池   智能纺织品   可穿戴设备   柔性电子   集成策略  

摘要： 针对柔性智能纺织品缺乏与之匹配的储能系统这一发展瓶颈,文章旨在探讨水系锌离子电池作为其理想供能方案的可行性与发展路径。文章系统综述了水系锌离子电池的工作原理,并剖析了其在安全性、柔韧性与纺织工艺兼容性方面的核心优势。在此基础上,重点梳理了锌离子电池与纺织品一体化的集成策略,包括纤维状、织物状及微电网式结构,并结合实例展望了其在健康监测、智能运动及军事等领域的应用前景。研究认为,水系锌离子电池在柔性纺织领域具有巨大潜力,但当前仍面临锌负极稳定性、封装可靠性及规模化制造等挑战。未来研究需聚焦开发新型锌基复合材料与智能电解质,并通过深化“结构—功能”一体化设计,以推动高性能、高可靠性柔性储能纺织品的实际应用。

关键词： 水平位移监测   计算机辅助设计   虚拟基线   视准线法   测量机器人  

摘要： 针对传统视准线法在复杂条件下适用性差和观测精度不可靠等问题,本文提出并构建了一种基于计算机辅助设计(CAD)平台的虚拟基线法,用于模拟视准线法进行水平位移监测,实现了全过程的自动化操作流程,并对该方法的技术流程、精度计算规则及对基线拟合精度的影响进行了典型工程应用与解析。结果表明,该方法通过建立虚拟基线,设计优化监测网,自动化数据采集,以及基于基线拟合与解算模型的数据处理,克服了传统方法对固定基准点和直接通视的依赖,在测区视线困难、可设点困难或超远距离等情形下,水平位移监测的自动化和测量可靠性是切实可行的,值得推广应用。