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关键词： Quantum yield   Photostability   Photobleaching   Fluorescence   Chromophores  

摘要： Fluorescent proteins (FPs) have become ubiquitous tools for biological research and concomitantly they are intriguing molecules that are amenable to study with a wide range of experimental and theoretical tools. This perspective explores the connection between the engineering of improved FPs and basic ideas from physical chemistry that explain their properties and drive the molecular design of brighter and more photostable variants. We highlight some of the progress and the many knowledge gaps in understanding the relationship between FP brightness and photostability. We also explore some of the pertinent remaining questions and suggest ways in which physical chemists might further examine the physical basis of brightness and photostability in these systems.

关键词： Fruits  

摘要： A gluten-free rice flour-based cookie was produced using different mixtures of chestnut flour (0, 30, 40, and 50%), date seed flour (0, 10, and 20%), and modified starch (0.3, 0.5, 0.6, and 0.9%). Physicochemical, rheological, and sensory properties of the prepared treatments were investigated. The results showed that moisture, specific volume, and dough viscosity were the lowest in control and the highest in treatment T1 containing 20% date seed flour, 30% chestnut flour, and 0.9% modified starch (P < 0.05). The highest (22.15 N) and the lowest hardness (13.5 N) were obtained in the control and T1, respectively, both of which increased over the storage time (P < 0.05). Regarding the texture characteristics of different dough treatments, the control illustrated the lowest adhesiveness and the highest hardness and chewiness. Sensory evaluation revealed that gluten-free treatments were acceptable from the consumers' point of view. It was concluded that T1 as a gluten-free cookie had the highest quality.

关键词： 物理化学   RDX   GO   PBX   安全性能   力学性能  

摘要： 为改善RDX的安全性能和力学性能,采用乳液聚合法制备RDX/聚甲基丙烯酸甲酯/氧化石墨烯(RDX/PMMA/GO)微球,并用相同方法制备了RDX/PMMA复合粒子进行对比;通过扫描电子显微镜(SEM)、X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FT-IR)和差示扫描热量仪(DSC)对样品进行表征,并测试其撞击感度和药柱的静态力学性能。结果表明,包覆后RDX/PMMA微球形貌趋于球形,RDX/PMMA/GO粒子存在明显的层状皱褶;RDX晶型均未发生改变;与原料RDX和RDX/PMMA相比,RDX/PMMA/GO微球的表观活化能分别提高22.16kJ/mol和15.17kJ/mol,升温速率趋近于0时的峰温和热爆炸临界温度与原料RDX相比分别提升6.45℃和6.23℃;特性落高由包覆前的26.74cm分别提至62.95cm和78.52cm,撞击感度明显降低。RDX/PMMA/GO抗压强度比RDX/PMMA增加了7.5MPa,表明GO的加入对复合材料的力学性能提升明显。

关键词： 物理化学实验   Python   数据处理  

摘要： 该文以乙酸乙酯皂化反应速率常数的测定和原电池电动势的测定为例,介绍了将Python语言用于物理化学实验的数据处理的方法,与传统的实验数据处理方法相比,用Python语言处理实验数据具有操作方便,处理效率高,误差小的优点。同时开拓了学生思维,培养和提高了学生的创新能力。

关键词： Xanthone   drying technology   solubility enhancement   coacervation   microencapsulation   aqueous solubility  

摘要： This study aims to compare the effect of different drying techniques (oven-, spray-, and freeze drying) on xanthone, a poorly aqueous-soluble bioactive compound, encapsulated by coacervation using gelatin and gum Arabic. Free-flowing spherical shape powders were produced except for freeze drying that resulted in a stratified cell-like structure. Fourier transform infrared spectroscopy confirmed no interaction between xanthone and wall material. Among the drying techniques, spray dried resulted in the lowest yield and encapsulation efficiency (EE) but the highest improvement (ninefold) in xanthone aqueous solubility from 2.6 mu g/mL to 22.32 +/- 5.99 mu g/mL. Freeze drying resulted in the highest encapsulation yield (75.4%) and EE (68.2%). Besides the solubilizing effect of wall material, the drying technique demonstrates a significant effect (p < 0.05) on xanthone's aqueous solubility. In summary, this study provides insights into the influence of drying techniques on the physicochemical properties of xanthone coacervates, which has potential usage in food and pharmaceutical industries.

关键词： “物理化学实验”   教学模式   微课程   虚拟实验  

摘要： 随着现代信息技术的飞速发展和网络资源的不断丰富,将微课程和虚拟实验引入到“物理化学实验”教学中成为可能。文章以“蔗糖水解反应动力学”实验为例,提出了一种“线上线下—虚拟实验与微课程相结合”的“物理化学实验”教学新模式,有效弥补了传统实验教学中存在的不足,解决了实验仪器短缺、实验存在安全隐患、实验时间和地点受限等问题,激发学生对“物理化学实验”的兴趣,培养创新意识,提高实践能力。

关键词： 物理化学   课程思政   表面化学   专业知识与思政元素融合  

摘要： “物理化学”是中医药院校重要的专业基础课程,在专业建设中起着承上启下的枢纽作用,肩负着课程思政建设立德树人的重要使命。表面化学是“物理化学”的重要分支,从教学实践中选择五个重要的专业知识点,通过教师引导与学生主体探讨,挖掘其中所蕴藏的思想政治教育元素,阐述了“透过现象看本质、勇于突破和创新、稳定和谐促发展、团队合作实现共赢、加强自身内涵建设”五个思政教育主题。在表面化学专业知识与思政元素的融合中,师生共同探讨如何在“物理化学”专业知识传授过程中更好地贯穿思政教育,以期实现课程价值塑造、知识传授和能力培养的“三位一体”育人目标。

关键词： 物理化学   黏结剂   表面自由能   增塑剂   HTPB   DOA   DOS   DOP  

摘要： 为了研究不同黏结体系的表面自由能随温度的变化规律,利用表面能测试仪器测试了HTPB黏结体系的表面自由能,分析了HTPB与增塑剂体积比、增塑剂种类、温度对体系表面自由能的影响。结果表明,HTPB在所给温度范围内表面自由能基本无变化;己二酸二异氰酸酯(DOA)的表面自由能随温度升高呈现线性降低;在HTPB/DOA不同的体积浓度的混合溶液中,当HTPB/DOA体积比为1∶1时,在工艺温度60~65℃范围内,表面自由能最低;在DOA、癸二酸二辛脂(DOS)、邻苯二甲酸二辛脂(DOP)三种增塑剂分别与HTPB体积比1∶1混合时,在工艺温度60~65℃范围内,HTPB/DOA的黏结体系具有更低的表面自由能,DOA增塑效果最好;不同黏结剂体系的表面自由能对温度的灵敏度具有较大差异,其中HTPB/DOA黏结体系的表面自由能对温度更灵敏。

关键词： 物理化学   雨课堂   教学   改革   实践  

摘要： 新工科是当下双一流高校的重要发展方向,其目标是培养创新型和善用自然之理的人才。物理化学由于其逻辑性强、概念抽象等特点,在培养学生创新能力中大有裨益。创新能力的培养需要激发学生的主观创造力。雨课堂能实现师生间良好的沟通、互动,以及对已学知识的巩固和运用,对于创新能力的培养具有实际意义。笔者基于雨课堂平台,对物理化学教学提出几点改革的看法,以供相互交流和学习之用。

关键词： Ascorbic acid  

摘要： In tomato drying, degradation in final quality may occur based on the drying method used and predrying preparation. Hence, this research was conducted to evaluate the effect of different predrying treatments on physicochemical quality and drying kinetics of twin-layer-solar-tunnel-dried tomato slices. During the experimental work, tomato slices of var. Galilea were used. As predrying treatments, 0.5% calcium chloride (CaCl2), 0.5% ascorbic acid (C6H8O6), 0.5% citric acid (C6H8O7), and 0.5% sodium chloride (NaCl) were used. The tomato samples were sliced to 5 mm thickness, socked in the pretreatments for ten minutes, and dried in a twin layer solar tunnel dryer under the weather conditions of Jimma, Ethiopia. Untreated samples were used as control. The moisture losses from the samples were monitored by weighing samples at 2 h interval from each treatment. SAS statistical software version 9.2 was used for analyzing data on the physicochemical quality of tomato slices in CRD with three replications. From the experimental result, it was observed that dried tomato slices pretreated with 0.5% ascorbic acid gave the best retention of vitamin C and total phenolic content with a high sugar/acid ratio. Better retention of lycopene and fast drying were observed in dried tomato slices pretreated with 0.5% sodium chloride, and pretreating tomatoes with 0.5% citric acid resulted in better color values than the other treatments. Compared to the control, pretreating significantly preserved the overall quality of dried tomato slices and increased the moisture removal rate in the twin layer solar tunnel dryer.