Results 41 to 50 of about 12,267 (168)
Network Public Opinion Analysis and Its Application Research Based on Topic Model [PDF]
, 2017 随着“互联网+”战略的深入贯彻，网络舆情已经成为把握时下舆论热点的先锋战场。鉴于网络舆情的重要地位，本文在研读有关网络舆情发展现状和主题模型应用的基础上，提出自适应标签主题模型（ALS-TM）与自适应时间窗动态主题模型（ATS-DTM）两个主题模型，分别从静态和动态两个角度捕捉舆情热点及其演化方向。第一部分，本文提出基于静态视角下的主题模型：自适应标签主题模型，用以提高主题解释力。ALS-TM模型结合主题聚合度指标与K-Means聚类算法，寻找最优分类标签，以此增强主题提取效率。实验结果表明：第一 ...
于学伟
core
Rare Metals, Volume 45, Issue 4, April 2026.ABSTRACT This study successfully prepared a high‐palladium (Pd)‐loading (51 wt%) Pd/Al2O3 composite through multiple wet impregnation. The material exhibited excellent hydrogen isotope separation performance, with metal–support interactions endowing it with a higher plateau pressure and lower desorption temperature.
Long Liang +10 more
wiley +1 more source
Gaoya dianqi, 2012 温度是油纸绝缘老化的主要因素。笔者设计了油浸式电力变压器常用的普通牛皮纸和环烷基矿物油复合绝缘在90℃下长达370 d的热单因子老化试验。利用XRD（X射线衍射）定期测量不同老化状态的绝缘样品,对比分析了绝缘纸的聚态结构的变化情况,并深入讨论绝缘纸聚合度下降的动力学过程。研究结果表明:绝缘纸在老化过程中,纤维素氢键和糖苷键发生断裂,引起聚合度下降,结晶区遭受破坏,晶粒尺寸减小,导致纤维素分子间作用力减弱,热裂解活化能降低;老化过程中,绝缘纸纤维素晶体类型不变,聚合度的下降规律符合二阶动力学模型 ...
向彬 +4 more
doaj
Shuitu Baochi Xuebao, 2020 为探究紫色土坡地植物篱篱前淤积带与篱下土坎土壤抗蚀性的差异及变化规律，选取遂宁市水土保持试验站10°新银合欢植物篱小区（T1）、10°和15°香根草植物篱小区（T2和T3）进行研究。研究小区布设有上、中、下坡篱带，分别采集篱前淤积带和篱下土坎（下坡无）的表土样，测定有机质含量、水稳性团聚体和微团聚体组成，运用主成分分析法对土壤抗蚀性进行分析。结果表明：同一篱带，土壤有机质含量、团聚度和团聚状况均是篱前淤积带高于篱下土坎，土壤水稳性团聚体含量和抗蚀性综合指数则反之，篱下土坎的抗蚀性综合指数是篱前淤积带的1.
王针针 +5 more
doaj
Rare Metals, Volume 45, Issue 4, April 2026.ABSTRACT Formic acid (FA) is considered to be a safe and convenient hydrogen source; however, achieving controlled and efficient FA dehydrogenation under mild conditions using stable solid catalysts remains a significant challenge. Pd‐based catalysts have been extensively studied due to their superior catalytic activity to other metal catalysts.
Shuai Wei +10 more
wiley +1 more source
Asian Politics &Policy, Volume 18, Issue 2, April 2026.ABSTRACT This study reframes Hong Kong's Legislative Council geographical constituency elections as a case of limited competition produced by institutional design. Using candidate‐level data, we examine how organizational resources and competition structure shape electoral outcomes under a mixed system that combines proportional representation in GCs ...
Pei ZHI, Fen LIN
wiley +1 more source
Jianzhu Gangjiegou Jinzhan, 2018 研究了一种新型预制冷弯薄壁型钢-轻聚合物复合墙体,即在冷弯薄壁型钢骨架内部喷涂轻聚合物填料,并在墙体一侧喷涂轻聚合物保温层,在另一侧拼装石膏板或水泥纤维板。进行了4个足尺预制冷弯薄壁型钢-轻聚合物复合墙体的抗弯性能试验,详细考察了墙体在均布荷载作用下的破坏模式和应变分布规律,研究了墙体抗弯承载力和荷载-挠度曲线。试验研究表明,预制冷弯薄壁型钢-轻聚合物复合墙体具有良好的抗弯承载力,其抗弯承载力为自重的10.7119.14倍;内部填料类型和墙面板类型对复合墙体抗弯承载力和挠度有一定影响 ...
王静峰, 庞帅, 鲁萌萌, 仇多宏
doaj
Study on structures and activities of vegetable tannins [PDF]
, 2014 摘要 植物单宁由于其复杂多样的结构和特殊丰富的生物活性，在医药、食品、农业、材料、化工、林业、环境、生态等多学科领域得到了广泛的应用，逐渐成为植物化学、药理学和食品化学等交叉学科的研究热点。方便快捷而又精准可靠的化学结构鉴定分析能有效帮助我们筛选和开发具有重大应用价值的植物单宁资源。本研究应用基质辅助激光解吸附离子化飞行时间质谱（MALDI-TOFMS）、高效液相色谱-电喷雾电离质谱（HPLC-ESI-MS）、核磁共振（NMR）、化学降解法等方法联合分析鉴定不同植物来源单宁结构 ...
柴纬明
core
Integrative Conservation, Volume 5, Issue 1, Page 59-73, March 2026.This research reveals the functional stability of mixed species foraging flocks (MSF) and their foraging height change with different taxonomic differences along the elevational gradient at Knuckles Montane Reserve, Sri Lanka. This offers new insights into how MSFs sustain with the elevational gradients supporting the altitudinal shifting species ...
Vimukthi. R. Gunasekeara +3 more
wiley +1 more source
Gaoya dianqi, 2023 环氧树脂在直流电场下易于积聚电荷造成局部电场畸变，进而诱发沿面闪络。文中建立了考虑离子产生、复合、迁移和扩散过程的电荷积聚模型，并在模型中计及了电导率的温度特性。研究了不同温度下气固界面电势、电场、电荷的分布及功率损耗变化，分析了温度对电荷行为和电场畸变率的影响。结果表明：表面电荷密度随温度升高而增大，三结合点处电荷密度最大；温度对切向电场的影响更大，随温度升高，电荷积聚的主要方式由表面传导向体传导转变；适当升温可以提高表面电荷积聚和消散速率，但高温会使表面电荷密度和泄漏电流增大，进而加剧畸变和损耗 ...
谢子豪 +5 more
doaj