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关键词： Hydroxypropyl methylcellulose   Ocular drug delivery   Ocular formulations   Eye  

摘要： Hydroxypropyl methylcellulose (HPMC) is a cellulose ether widely used in drug formulations due to its biocompatibility, uncharged nature, solubility in water and thermoplastic behavior. Particularly for ocular and ophthalmic formulations, HPMC is applied as viscosity enhancer agent in eye drops, gelling agent in injections, and polymeric matrix in films, filaments and inserts. The different therapeutic approaches are necessary due to the complex anatomic structure of the eye. The natural ocular barriers and the low drug permeation into the circulatory system make the drug administration challenging. This review presents the eye anatomy and the usual local routes of drugs administration, which are facilitated by the physicochemical properties of HPMC. The relationship between chemical structure and physicochemical properties of HPMC is displayed. The different types of formulations (local application) including HPMC for ocular drug delivery are discussed with basis on recent literature reports and patents.

关键词： Layered double hydroxide   Adsorption   Antimony removal   Fluoride removal   Kinetics  

摘要： A series of novel adsorbents composed of cellulose(CL)with Ca/Al layered double hydroxide(CC_(x)A;where x represent the Ca/Al molar ratio)were prepared for the adsorption of antimony(Sb(V))and fluoride(F^(-))ions from aqueous *** CC_(x)A was characterized by Fourier-transform infrared spectroscopy(FTIR),Brunauer–Emmett–Teller(BET),elemental analysis(CHNS/O),thermogravimetric analysis(TGA-DTA),zeta potential,X-ray photoelectron spectroscopy(XPS)and scanning electron microscopy with energy dispersive Xray spectroscopy(SEM-EDX)*** effects of varying parameters such as dose,pH,contact time,temperature and initial concentration on the adsorption process were *** to the obtained results,the adsorption processes were described by a pseudo-second-order kinetic *** adsorption isotherm model provided the best fit for the experimental data and was used to describe isotherm *** maximum adsorption capacity was found to be 77.2 and 63.1 mg/g for Sb(V)and F^(-),respectively by CC_(3)A(experimental conditions:pH 5.5,time 60 min,dose 15 mg/10 mL,temperature 298 K).The CC_(3)A nanocomposite was able to reduce the Sb(V)and F^(-)ions concentration in synthetic solution to lower than 6μg/L and 1.5 mg/L,respectively,which are maximum contaminant levels of these elements in drinking water according to WHO guidelines.

关键词： Ecosystem engineer   Soil biota   Ornithic qualifier   Pedogenesis  

摘要： The physiological and behavioural activities of animals have far-reaching impacts on the characteristics and functioning of soil. This includes vertebrates, which are capable of modifying the physicochemical and biochemical properties of soil. To date, however, no species is known to be responsible for the entire process of soil formation, modification and maintenance. Large-bodied birds build nests which they then use for several years or even decades. During nest construction or renovation, birds gather and transport to the nesting site organic and mineral matter that includes tree branches of various sizes, twigs, turf, straw and hay. Over time, during subsequent breeding events, adult birds supply further loads of organic matter to the nest, such as food remains, excrement, pellets, feathers, egg shells and other materials. Taking the White Stork Ciconia ciconia as an example, we have shown that the materials deposited in the nests of large-bodied birds gradually produce ornithogenic soils over the years, with distinguishable layers having different physicochemical characteristics and biochemical activities. The tested nesting substrate met the criteria for ornithogenic material;the layers had appropriate thickness and phosphorus pentoxide (P2O5) content. Results of the study indicates that the material contained in White Stork nests have the characteristics of Histosols. Moreover, such nests harbour assemblages of fungi and arthropods that contain species typical of soil mycobiota and fauna, respectively. This study is the first to describe a soil that is formed, modified and maintained entirely by vertebrates and is physically isolated from the ground. Our results highlight the fact that the nests of large birds are unique structures in ecosystems and provide a habitat for a rich and diverse assemblage of organisms. (C) 2020 Elsevier B.V. All lights reserved.

关键词： 物理化学   包覆   燃烧性能   片状变燃速发射药   数值计算  

摘要： 为研究包覆方式对片状发射药燃烧性能的影响,建立了不同包覆方式下多层片状发射药的物理模型,并推导了形状函数和燃气生成猛度表达式,利用Matlab软件对不同的宽厚比、长厚比及多层结构的片状发射药进行了数值计算;制备了不同长厚比的片状变燃速发射药,并进行了密闭爆发器实验。结果表明,四面包覆和全包覆可以很好地消除临界宽厚比对片状发射药燃烧性能的影响;与两面包覆的片状发射药相比,四面包覆和全包覆的片状发射药能够延缓内层药减面燃烧的时间,其燃气生成猛度的阶跃程度分别提高了1.17%和1.23%,呈现出良好的燃烧渐增性。

关键词： 物理化学   FOX-7   超低温重结晶法   颗粒尺寸   热性能   机械感度  

摘要： 为了制备出粒径均匀且分散性较好的纳米FOX-7,采用液氮超低温重结晶法在不同溶剂条件下制备了纳米FOX-7;采用场发射扫描电子显微镜(FE-SEM)、X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、差示扫描量热法(DSC)、热重分析法(TG)对所制备的纳米FOX-7的性能进行了表征,并测试了其撞击感度和摩擦感度。结果表明,所制备的纳米FOX-7的平均晶粒度为30nm左右,颗粒平均粒径均在100~200nm之间;与原料FOX-7相比,其高低温分解放热峰之间的温度范围变窄,能量释放效率及分解放热焓有较大提高,撞击感度和摩擦感度明显降低。不同溶剂由于其溶解度和极性的不同,所制备样品的颗粒粒径有所不同,溶解度与极性越大,所制备的颗粒粒径越小、热性能越好、感度更低。当溶剂为N-甲基吡咯烷酮时,所制备的纳米FOX-7的颗粒粒径在100nm以下占比为18%,初始分解峰温提高了11.8℃,分解放热焓提高了19%,特性落高从87.2cm提高至138.2cm,摩擦感度从216N提高至360N。

关键词： 物理化学   热力学   基本方程   非体积功  

摘要： 热力学基本方程是物理化学课程中一个重要的知识点。现行物理化学教材中重点阐述了仅含有体积功的热力学基本方程,而对涉及非体积功的热力学基本方程介绍很少。对材料类专业的学生来说,学习和研究材料热力学,经常会涉及到非体积功。因此,学习涉及非体积功的热力学基本方程非常必要。本文重点讨论了涉及非体积功的表面系统、弹性杆、电、磁介质中的热力学基本方程的推导和应用,并总结了处理这类问题的方法。

关键词： 物理化学实验   教学   改革  

摘要： 分析了物理化学实验的课程特点和教学实施中面临的问题,分别从教学安排、教学模式、教学内容和数据处理软件教学几个方面讨论了物理化学实验教学的改革措施。

关键词： 师生关系   卢嘉锡   田昭武   物理化学   化学学科   新生   电化学  

摘要： 田昭武1945年从福建省立永安中学毕业,被保送厦门大学化学系,成为新生院的一名新生。同一年,卢嘉锡先生辞却了国外一切聘任,毅然回国,受聘为厦门大学化学系教授。这似乎是一种巧合,更是一种缘分,从此留下了他们特殊师生关系的一段佳话。在卢嘉锡先生的安排下,田昭武比别人多学好几门化学学科之外的课程。同样,在卢嘉锡先生的安排下,田昭武毕业留校后先后担任物理化学和物质结构两门重要课程的助教和主讲。而后,在卢嘉锡先生的默许和鼓励下,田昭武走上了电化学科研之路。

关键词： Choline acetate   Choline chloride   Carboxylic acids   Urea   Deep eutectic solvents  

摘要： In this work the physicochemical properties of newly obtained mixtures (ChM) based on choline acetate (ChAc)/chloride (ChCl) as a hydrogen bond acceptor (HBA) and carboxylic acids (oxalic (OxA), malonic (MA), citric (CA), acetic (AA), formic (FA))/urea (U) as a hydrogen bond donors (HBD) are discussed. NMR study showed slow reaction between choline and carboxylic acid, leading to obtain ester and water. After 3 weeks of synthesis, water content (w(H2O)) increased ca. 1.4 and 1.9 times for ChAc+FA and ChAc+OxA respectively. This factor is acid strength (as HBD) dependents. Moreover, the results clearly shown that w(H2O) can be rapidly determined based on the measurements of the refractive index. The densities of the examined systems are in the range 1.084-1.296 ***(-3) at 298.15 K, while kinematic viscosity at the same temperature varies from ca. 19 cSt to 2190 cSt for ChAc+FA and ChAc+CA respectively. The highest conductivity was measured in ChCl+FA system and equaled 14.60 ***(-1). (C) 2020 Elsevier B.V. All rights reserved.

关键词： 智慧制造   造渣   精炼   连铸   中间包  

摘要： 依据公开文献报道讨论目前宝钢股份智能化生产发展概况,基于生产数据及冶金理论,针对宝钢产品中夹杂物的控制,从转炉、精炼、连铸等重点工序展开,讨论了转炉造渣控制、精炼OB(Oxygen blowing)控制,以及连铸的吹氩控制。基于冶金理论重点阐述了精炼吹氧脱碳、连铸中间包吹氩对液态钢水中氧的影响,阐明钢铁工业中工艺数据与冶金原理密切结合起来,才能推动冶金工业智能制造更好的发展。