氧化石墨烯改性密胺树脂/石蜡相变微胶囊的制备及性能

通过原位聚合法制备了氧化石墨烯(GO)改性的密胺树脂(MF)/石蜡相变微胶囊。采用红外光谱、扫描电镜、差示扫描量热分析、热重分析等手段分析了相变微胶囊的微观结构及热性能,研究了GO含量对相变微胶囊形貌、包覆率和渗漏率的影响。研究结果表明,制备的相变微胶囊为较规则的球形,GO的加入并没有改变壁材或芯材的化学结构;GO改性使相变微胶囊的包覆率由91.39%提高至94.08%,增大了相变微胶囊的储能能力;GO改性相变微胶囊的防渗性能得到大幅提升,250h时的渗漏率由9.43%下降至2.68%,下降了71.6%,相变微胶囊的使用寿命得到提高。     

Numerical simulation of heat transfer of latent functionally thermal fluid in tubes with coaxially inserted cylindrical bars in laminar

The heat transfer of latent functionally thermal fluid in three kinds of tubes with coaxially inserted cylindrical bars is numerically researched using equivalent specific heat model, and the flow fields are analyzed with field synergy field. It is found that in the tubes with coaxially inserted cylindrical bars, the heat transfer effects of functionally thermal fluid become more and more pronounced with the Ste decreasing. This is similar to be case of functionally thermal fluid flowing in smooth straight tubes. Compared with the results receiving from smooth straight tubes, the heat transfer of functional thermal fluid in tubes with coaxially inserted cylindrical bars has been significantly enhanced. And this effect becomes more apparent as the diameter of coaxially inserted cylindrical bars increases meanwhile, however, energy consuming of the tubes shows the same trend. Supported by the Key Project of National Natural Science Foundation of China (Grant No. 50436020)     

改性微胶囊化聚磷酸铵阻燃天然橡胶

本文通过原位聚合法制备了聚乙烯醇（PVA）改性的三聚氰胺（MEL）-甲醛树脂（VMF）微胶囊,对聚磷酸铵（APP）/介孔分子筛MCM-41进行包覆,得到了一种新型的核壳结构的微胶囊阻燃剂（MVMF-(A/M)）。通过红外光谱分析（IR）、溶解度和扫描电子显微镜（SEM）对包覆前后的阻燃剂结构以及形貌进行表征。并将其加入到天然橡胶（NR）中,通过氧指数测试（LOI）、垂直燃烧测试（UL-94）、热失重分析（TG）、拉伸测试研究了NR复合材料的阻燃性能和力学性能。实验结果表明：制备的MVMF-(A/M)在20℃水中的溶解度为1.59mg /L,相比APP溶解度降低51.2%, MVMF-(A/M)粒子表面变得粗糙;与其他阻燃天然橡胶体系相比添加了MVMF-(A/M)的NR复合材料的极限氧指数最高, UL-94达到了V-0级别,拉伸强度为8.84MPa,断裂伸长率为310.20%。     

近岸岛屿联合作战船艇装备保障力量部署方法

为实现对船艇装备保障力量部署问题的定量研究,采用约束满足问题的理论与方法,通过对近岸岛屿联合作战中船艇装备保障力量部署体系的分析和对保障阶段、保障区域、保障节点的划分及相关参数的简化与设置,构建了数学模型。该方法对战时船艇装备保障力量的部署具有一定的指导作用。     

等热流圆管内相变微胶囊悬浮液层流换热实验研究

用基液代替水来配置微胶囊相变悬浮液,并对实验数据的准确性进行了检验。在等热流密度环境下对管道内的该悬浮液进行加热实验,对相变微胶囊悬浮液的质量分数、St、入口过冷度、粒径和Re等因素影响强化换热的效果进行了分析。结果显示影响微胶囊相变悬浮液管内层流换热最主要的因素是微胶囊的质量分数和St。     

相变微胶囊的制备及其在微通道的应用进展

相变微胶囊是一种性能良好、稳定性强的相变储能材料,其热导率偏低,但对相变微胶囊进行改性以及优化换热条件可以提高热导率。本文系统地介绍了相变微胶囊与改性相变微胶囊的制备方法,以及两者的区别。文章指出,对比分析可知,原位聚合法是制备改性相变微胶囊最常用的方法,对壁材进行改性是最常用的改性方法,并且在众多改性材料中氧化石墨烯是一种高导热、力学性能优异、稳定性强的改性材料。同时,文中对相变微胶囊和改性相变微胶囊在微通道换热器中的应用进行概述与总结,指出其中存在的问题：相变微胶囊与微通道换热器的结合,在提升换热效果的同时还存在着增加流动阻力和压降的问题。因此需要确定悬浮液流动的临界速度,充分发挥相变微胶囊与微通道换热器的优势。     

Necrostatin-1 Supplementation to Islet Tissue Culture Enhances the In-Vitro Development and Graft Function of Young Porcine Islets

Pre-weaned porcine islets (PPIs) represent an unlimited source for islet transplantation but are functionally immature. We previously showed that necrostatin-1 (Nec-1) immediately after islet isolation enhanced the in vitro development of PPIs. Here, we examined the impact of Nec-1 on the in vivo function of PPIs after transplantation in diabetic mice. PPIs were isolated from pancreata of 8–15-day-old, pre-weaned pigs and cultured in media alone, or supplemented with Nec-1 (100 µM) on day 0 or on day 3 of culture (n = 5 for each group). On day 7, islet recovery, viability, oxygen consumption rate, insulin content, cellular composition, insulin secretion capacity, and transplant outcomes were evaluated. While islet viability and oxygen consumption rate remained high throughout 7-day tissue culture, Nec-1 supplementation on day 3 significantly improved islet recovery, insulin content, endocrine composition, GLUT2 expression, differentiation potential, proliferation capacity of endocrine cells, and insulin secretion. Adding Nec-1 on day 3 of tissue culture enhanced the islet recovery, proportion of delta cells, beta-cell differentiation and proliferation, and stimulation index. In vivo, this leads to shorter times to normoglycemia, better glycemic control, and higher circulating insulin. Our findings identify the novel time-dependent effects of Nec-1 supplementation on porcine islet quantity and quality prior to transplantation.     

大豆/PTT微胶囊分散染料/活性染料一浴一步法染色

探讨了纯碱和氯化钠用量、染料浓度对微胶囊分散蓝2BLN/活性染料(活性蓝KN-R、活性深蓝B-2GLN和活性蓝K-3RL)一浴法染色大豆/PTT混纺织物表观色深K/S值的影响,测定了不同染色工艺对染色织物牢度的影响.结果表明:当染料总用量为2％(o.w.f.),纯碱用量1g/L,氯化钠用量20 g/L,95℃条件下保温30分钟时,可使大豆/PTT混纺织物获得较高的表观色深.     

海藻酸钠凝胶机制及其在食品中的应用研究进展

海藻酸钠作为一种天然多糖,具有良好的功能特性,在食品中得到普遍应用.生产实践中主要使用钙盐制备水凝胶,凝胶形成的网络结构可以提高食品特性.它的形成受到海藻酸钠的浓度、结合钙离子浓度、温度、pH值等因素的影响.海藻酸钠凝胶在食品应用领域中备受关注,尤其是在微囊化、可食性膜、质地改良等方面应用广泛.     

微胶囊化蒜粉的贮存稳定性

研究了微胶囊化蒜粉的贮存稳定性,并与蒜粉做了比较。结果表明,微胶囊化蒜粉贮存10个月后,硫代亚磺酸酯心材保留率仍在95%以上。DSC测定蒜粉的玻璃化转变温度为-2.9℃,微胶囊化蒜粉的玻璃化转变温度为112℃。采用SEM观察微胶囊化蒜粉内部与外部结构,发现微胶囊化蒜粉表面具有很好的完整性和致密性。因而微胶囊化蒜粉具有良好的贮存稳定性。