锌负极材料锌酸钙的晶体形貌和物化性质研究

0引言 碱性可充锌基电池因其具有能量密度高、无环境污染而引起人们的广泛重视.上世纪70年代掀起了二次锌电极研究的热潮.但电极材料的形变、枝晶等问题依旧影响了锌电极的开发利用.     

饱和链烃类化合物的物理化学性质的分子拓扑研究

从距离矩阵和原子的支化度出发,提出了一种新的拓扑指数,计算结果表明,它具有良好的结构选择性和性质相关性。     

微量元素对宝玉石物理性质的影响

微量元素的介入对宝石的形成是极其重要的。它们在宝石内部或发生类质同象替代，改变了宝石的一些物理性质，如宝石的颜色、荧光、折射率、密度，也会增加宝石一些特殊的光学效应，如变色效应，使宝石的外观变得更加绚丽多彩。     

Effect of Selective CF3 Substitution on the Physical and Chemical Properties of Gold Corroles

Gold corroles are not readily accessible and they display no interesting physical or chemical properties. A facile methodology has now been developed for obtaining selectively CF₃‐substituted gold(III) corroles and the introduction of these groups has been found to have an immense effect on the structures of the complexes, their photophysical and redox properties, and on their ability to participate in catalytic processes.     

Effect of Ultrasonic Pretreatment on Flocculation Filtration of Low-Rank Coal Slurry

The efficient filtration of low-rank coal (LRC) slurry was significantly beneficial to the production process of wet coal beneficiation. However, relatively few studies have been reported on novel pretreatment methods for the efficient filtration of LRC slurry. In this paper, the mechanism of ultrasonic pretreatment to promote flocculation and filtration of slurry was studied. The hydrophobic variation of the slurry surface was measured by contact angle and XPS. The flocculation properties of slurry were characterized using zeta potential and FBRM. The effects of filter cake porosity and ultrasonic pretreatment on slurry filtration resistance were calculated by L-F NMR and Darcy’s theory. The results showed that the ultrasonic pretreatment promoted the flocculation and filtration performance of LRC slurry, increased the filtration rate, and decreased the cake moisture content. Meanwhile, the contact angle of LRC increased significantly from 50.1° to 67.8° after ultrasonic pretreatment, and the surface tension of the filtrate decreased from 69.5 to 53.31 mN/m. Ultrasonic pretreatment reduced the absolute value of the zeta potential of coal slurry from 24.8 to 21.0 mV, and the average chord length of flocs increased from 5–10 μm to 25–30 μm, thus weakening the electrostatic repulsion between coals to promote floc formation. In addition, the pore tests and filtration theory calculations showed that the ultrasonic pretreatment significantly improved the permeability of the filter cake to water and reduced the resistance to slurry during filtration. In particular, the mesopore porosity increased by 9.18%, and the permeability increased by 2.937 × 10⁸ m². Therefore, this contributed to the reduction of slurry filtration resistance. This research provides an efficient method for promoting the efficient filtration of slurry.     

表面活性剂胶束化物理化学性质研究

通过电导法考查温度和盐浓度对十二烷基硫酸钠(SDS)临界胶束浓度(CMC)的影响,研究表面活性剂形成胶束过程的物理化学性质。根据拟相分离模型求得胶束化热力学函数,并讨论体系电导活化能随温度和SDS浓度变化关系。结果表明:SDS的CMC随温度升高而增加,随氯化钠浓度增大而减小。在热力学上SDS在水溶液中形成胶束是一个自发、放热、熵增的过程;在动力学上,SDS溶液电导率与温度关系符合Arrhenius公式,通过电导活化能信息可揭示离子型表面活性剂形成胶束的机理特征。     

Effect of Chemical Treatment on the Mechanical and Water Absorption Properties of Coir Pith/Nylon/Epoxy Sandwich Composites

Multilayered coir pith/nylon fabric/epoxy hybrid composites were fabricated by the hand lay-up technique. Coir pith was subjected to chemical treatment before processing and the volume fraction of coir pith was maintained in the range of 60–65%. The effect of treatment was analyzed by SEM and optical microscopy. The effects of layering and treatment on the mechanical and water transport nature of composite were analyzed. The mechanical properties of the composite decreased on exposure to water. However, the retention of impact strength increased with chemical treatment of coir pith.     

Chemically Modified Graphene: The Influence of Structural Properties on the Assessment of Antioxidant Capacity

Graphene materials obtained by different synthetic routes possess dissimilar amount of defects and surface functionalities, which can influence their electrochemical performance towards the detection of electroactive probes. Oxygen‐containing groups can be either detrimental to the heterogeneous charge transfer or promote favorable interactions between the graphene surface and the analyte of interest, depending on the structure of the latter. Here, we compared three chemically modified graphenes, obtained by various procedures and carrying different amounts of oxygen functionalities, for the detection of standard gallic acid, a compound commonly used as an index of the antioxidant capacity of food and beverages. We found that electrochemically reduced graphene provided the best electrochemical performance in terms of calibration sensitivity, selectivity, and linearity of response. Our findings are important in order to understand the suitability of graphene platforms for the assessment of food quality.     

若干物理处理方法对稀土荧光粉Y2O3:Eu3+发光性能的影响

采用物理法对商品化稀土荧光粉Y2O3：Eu^3＋进行改性，考察了真空干燥温度、焙烧温度对其发光性能的影响。SEM和TEM观测结果表明，经过200℃真空干燥后，随着焙烧温度的增加，荧光粉的分散性得到改善，且以纳米颗粒为主（5～85nm）。XRD测量结果表明，随着焙烧温度的增加，Y203：Eu^3＋的结晶度逐渐增加。发射光谱测试结果表明，真空干燥温度为200℃，焙烧温度为1200℃时得到的样品的发光性能较好。     

物理化学综合实验:废弃贝壳制备环保净水剂及其对Pb2+的去除*

设计了一个包含贝壳净水剂的制备、平衡吸附量的计算和不同贝壳净水效果评价的物理化学综合实验。通过开展本实验,学生不仅可以了解重金属污染问题,更可以掌握净水剂的一般制备方法以及通过吸附实验对材料净水效果进行评价的基本手段。本实验可以将课堂学习的理论知识与生活中问题相结合,利用所学的知识解决实际问题,并培养严谨的科学思维和对物理化学学习的兴趣。     

4种保水剂吸水和保水性能的差异性研究

通过室内实验,对比研究了四种保水剂的吸水、保水性能。测试吸水倍率、吸水速率、保水能力及有效持续性等指标,采用评分法对四种保水剂进行综合评价。结果表明:保水剂的吸水倍率与所吸溶液的性质有很大关系。4种保水剂在去离子水中的吸水倍率最高,随着溶液中离子浓度的增大吸水倍率逐渐减小。保水剂颗粒大小对吸水速率有较大影响,对其他指标影响均不大;4种保水剂均具有较强的反复吸水能力。综合分析认为,4种保水剂中,吸水保水性能最优的保水剂为4#保水剂,其成分为聚丙烯酸盐和聚丙烯酰胺共聚体。其次为3#保水剂,再次为1#保水剂,最差的是2#保水剂。     

草坪剪草绿色素的提取与性质

本文研究了从草坪剪草中提取绿色素的方法，理化性质和稳定性，提取方法简便，在碱性和中性环境下，色素对热，光和大部分金属离子都是稳定的。     

A Review on the Extraction,Bioactivity, and Application of Tea Polysaccharides

Tea is a non-alcoholic drink containing various active ingredients, including tea polysaccharides (TPSs). TPSs have various biological activities, such as antioxidant, anti-tumor, hypoglycemic, and anti-cancer activities. However, TPSs have a complex composition, which significantly limits the extraction and isolation methods, thus limiting their application. This paper provides insight into the composition, methodological techniques for isolation and extraction of the components, biological activities, and functions of TPSs, as well as their application prospects.     

Effect of Hydration on Silk Film Material Properties

Effects of hydration on silk fibroin film properties were investigated for water‐annealed and MeOH‐treated samples. Hydration increased thickness by 60% for MeOH‐immersed films, while water‐annealed samples remained constant. MeOH‐immersed films showed an 80% mass loss due to water, while water‐annealed lost only 40%. O₂ permeability was higher in MeOH‐immersed films with Dk values of 10^?10 (mL O₂ · cm) · (cm^?1 · s^?1 · mmHg^?1), while those of water‐annealed films reached only one fifth of this value. All films showed a decrease in Young's modulus and increased plastic deformation by two orders of magnitude when submerged in saline solution. FT‐IR showed that β‐sheet content in water‐annealed films increased with increasing water vapor pressure, while MeOH‐immersed films showed no change.

     

超临界水的性质及其在化学反应中的应用

介绍了水的热物理性质、结构性质、离子积、扩散系数和粘度等在超临界区域的特殊性，以及超临界水溶液在介电常数、偏摩尔体积、溶解性和极性等方面的特殊性质，并阐述了超临界水的这种特殊性在化学反应和环境治理中的应用。     

疏水性咪唑类混合离子液体的物理化学性质

本文选取疏水性和疏水性离子液体混合物作为研究对象, 将疏水性离子液体1-甲基-3-n-丁基咪唑三氟甲基磺酰胺盐[BMImN(CF3SO2)2]与BMImPF6以不同的比例进行混合, 对混合离子液体及其相应单组分离子液体进行了相关物理化学性质的测试和对比, 讨论由于混合导致的物理化学效应.     

Design and Antioxidant Properties of Bifunctional 2H-Imidazole-Derived Phenolic Compounds—A New Family of Effective Inhibitors for Oxidative Stress-Associated Destructive Processes

The synthesis of inhibitors for oxidative stress-associated destructive processes based on 2H-imidazole-derived phenolic compounds affording the bifunctional 2H-imidazole-derived phenolic compounds in good-to-excellent yields was reported. In particular, a series of bifunctional organic molecules of the 5-aryl-2H-imidazole family of various architectures bearing both electron-donating and electron-withdrawing substituents in the aryl fragment along with the different arrangements of the hydroxy groups in the polyphenol moiety, namely derivatives of phloroglucinol, pyrogallol, hydroxyquinol, including previously unknown water-soluble molecules, were studied. The structural and antioxidant properties of these bifunctional 5-aryl-2H-imidazoles were comprehensively studied. The redox transformations of the synthesized compounds were carried out. The integrated approach based on single and mixed mechanisms of antioxidant action, namely the AOC, ARC, Folin, and DPPH assays, were applied to estimate antioxidant activities. The relationship “structure-antioxidant properties” was established for each of the antioxidant action mechanisms. The conjugation effect was shown to result in a decrease in the mobility of the hydrogen atom, thus complicating the process of electron transfer in nearly all cases. On the contrary, the conjugation in imidazolyl substituted phloroglucinols was found to enhance their activity through the hydrogen transfer mechanism. Imidazole-derived polyphenolic compounds bearing the most electron-withdrawing functionality, namely the nitro group, were established to possess the higher values for both antioxidant and antiradical capacities. It was demonstrated that in the case of phloroglucinol derivatives, the conjugation effect resulted in a significant increase in the antiradical capacity (ARC) for a whole family of the considered 2H-imidazole-derived phenolic compounds in comparison with the corresponding unsubstituted phenols. Particularly, conjugation of the polyphenolic subunit with 2,2-dimethyl-5-(4-nitrophenyl)-2H-imidazol-4-yl fragment was shown to increase ARC from 2.26 to 5.16 (10⁴ mol-eq/L). This means that the considered family of compounds is capable of exhibiting an antioxidant activity via transferring a hydrogen atom, exceeding the activity of known natural polyphenolic compounds.     

柠檬酸(铵)处理对Li[Li0.2Mn0.54Ni0.13Co0.13]O2电化学性能影响的研究

以共沉淀法制备的[Mn0.54Ni0.13Co0.13]1.25CO3为前驱体,配锂焙烧获得了富锂锰基固溶体Li[Li0.2Mn0.54Ni0.13Co0.13]O2,然后分别用柠檬酸、柠檬酸三铵对该材料进行表面预处理。结果表明经柠檬酸(铵)处理后,Li[Li0.2Mn0.54Ni0.13Co0.13]O2中分别有16.37wt%和13.14wt%的锂被化学脱出。充放电测试结果表明,表面处理后的样品首次效率有了较大的提高(由63.5%分别提高到了80.2%和80.7%),0.2C循环40次容量保持率分别由91.43%提高到97.42%和92.72%,1C容量由处理前的149.5 mAh.g-1提高到179.5mAh.g-1和181.5 mAh.g-1,表明处理后材料的循环性能和倍率性能都得到了改善。这主要是由于柠檬酸(铵)处理,预先脱出了Li2MnO3组分中的部分Li2O,并在材料表面生成了类尖晶石结构的材料。     

Antibacterial and Physical Properties of PVM/MA Copolymer- Incorporated Polymethyl Methacrylate as a Novel Antimicrobial Acrylic Resin Material

Polymethyl methacrylate (PMMA), an acrylic resin used in orthodontic appliances and removable dentures for its biocompatibility and esthetics, may harbor bacteria on its surface. The present study investigated a new PMMA formula with Gantrez: an antibacterial copolymer of methyl vinyl ether and maleic acid (PVM/MA). Samples were tested for mechanical properties (surface hardness, flexural strength, water sorption, and water solubility) and effects against Streptococcus mutans. Six groups (0%-control, 5%, 10%, 15%, 20%, and 25% Gantrez) of n = 12 were fabricated for physical property tests and analyzed with one-way ANOVA and Prism 6. From these results, three groups (0%, 5%, and 10% Gantrez) were selected for antibacterial tests, and data were analyzed with one-way ANOVA and Tukey’s multiple comparison test. Adding 5% and 10% Gantrez into PMMA significantly decreased S. mutans adhesion. There was no significant difference between the control vs. 5%, 10%, 15%, and 20% Gantrez (p > 0.05) for surface hardness, the control vs. 5% Gantrez (p > 0.05) for flexural strength, and the control vs. 5 and 10% Gantrez for water sorption and water solubility. Overall, incorporating 5% Gantrez into PMMA may be a promising solution to reduce bacterial adhesion without changing the acrylic resin’s physical properties.