Results 11 to 20 of about 4,973 (167)
, 2019 利用紫外老化箱对三元乙丙橡胶（EPDM）进行紫外光老化试验,采用核磁共振氢谱（1H-NMR）与傅里叶红外光谱（FT-IR）两种表征方法,追踪EPDM紫外光老化过程的化学结构变化,探讨了EPDM的老化机理。结果表明:EPDM的紫外光老化始于第3单体中活泼氢的断裂,氧化生成含氧产物,进而影响整个分子链。EPDM的抗紫外光老化性能较差,随着老化时间的延长,第3单体中的活泼氢的含量迅速减小,羰基含量呈现非线性增加。EPDM在紫外光老化过程中发生Norrish Ⅱ型光化学反应,生成了端烯烃结构。老化过程中生成了醇、
丁玲 +6 more
core +1 more source
Dianci bileiqi, 2023 室温硫化(RTV)硅橡胶老化程度的现场无损定量表征在实践中具有很重要的意义。笔者提出了采用指示剂的发光强度作为指征指标表征RTV硅橡胶老化程度的定量表征方法。通过以SrAl2O4∶Eu2+,Dy3+作为指示剂，采用人工加速老化的方式处理RTV硅橡胶，并测量了样品的余辉亮度、机械性能和表面形貌等。结果表明，■与人工加速老化处理时间呈线性关系。基于此，根据实际测量的■可以得到RTV硅橡胶老化程度。■的分布较窄表明本方法的精度较高；提供了本方法中对余辉强度测量的时间限制。证明了本方法的可行性。
夏兵 +8 more
doaj
Gaoya dianqi, 2020 对油中纸绝缘材料在不同温度条件下进行加速热老化试验,以绝缘纸聚合度作为诊断纸绝缘老化程度的标准,采用蒽酮比色法测量了老化油样中的总糖含量,探究油中总糖、糠醛与聚合度的相关性关系。研究表明:聚合度在1 000～600范围内对应的油样中的总糖含量均随着聚合度降低而逐渐增大且总糖含量比糠醛含量变化更显著,故在老化前中期阶段,油中总糖可作为新的特征量来表征油纸绝缘老化程度;聚合度在600～200范围内对应的油样中总糖含量未呈现出统一的变化规律,故在老化中后期阶段,总糖无法用来表征油纸绝缘老化程度 ...
付强 +4 more
doaj
Research Progress in the Effect of Thermal Treatments on the Structural and Physicochemical Properties of Starch [PDF]
, 2021 Starch is a very important plant polysaccharide, which is also an important industrial raw material for food production and processing.Since natural starch has poor heat, shear and acid resistance, and is easy to retrograde.It is necessary to carry out ...
CHEN Xiao-jing +5 more
core +1 more source
Effect of Different Modified Starches on Storage Quality of Protein Bars [PDF]
In order to mitigate protein bar aging during storage and enhance their sensory attributes, the effects of adding four different modified starches on protein bar aging were investigated in the present study through systematic measurements of hardness ...
Baoshang FU +5 more
core +1 more source
Fractal characteristics of fiber lithium slag concrete cracks under sulfate attack [PDF]
, 2022 Natural corrosion of concrete structure due to sulfate poses a serious threat to people's lives and property. Therefore, it is of great practical significance to study the phenomenon of sulfate corrosion on concrete.
Guang-tai ZHANG +3 more
core +1 more source
Study on the effects of adding konjac refined flour on the quality of fresh wet rice noodle [PDF]
, 2023 Objective: This study aimed to develop konjac rice noodles products with low glycemic index. Methods: The fresh wet rice noodles was made by adding 20%, 10% and 5% konjac refined flour into rice noodles, respectively.
GONG Xue +4 more
core +1 more source
Biodiversity‐driven spatial conservation planning to delineate temporally stable regions
Conservation Biology, EarlyView.Abstract The accelerating loss of biodiversity underscores the critical need for effective conservation strategies, particularly in the face of climate change and anthropogenic pressures. We devised a conservation planning framework that adopts a temporal stacking approach to species distribution models and landscape connectivity analyses. These models
Mattia Iannella +5 more
wiley +1 more source
International Journal of Applied Linguistics, EarlyView.ABSTRACT This study conducted linguistic analyses of the written corrective feedback (WCF) for Chinese as a second language (CSL) provided by chat generative pre‐trained transformer (ChatGPT) and human teachers (including preservice teachers and senior teachers).
Ling Zhang +2 more
wiley +1 more source
Effects of Oat Dietary Fiber on the Quality Characteristics and Anti-aging Ability of Chiffon Cake [PDF]
This study aimed to explore the appropriate range of oat dietary fiber addition for reducing the degree of starch aging while ensuring the quality of the cake.
Anqi XU +8 more
core +1 more source