Enzymatic Synthesis of Medium- and Long-Chain Triacylglycerols (MLCT): Optimization of Process Parameters Using Response Surface Methodology

The main objective of this study was to understand the effects and relationship amongst four factors, which are reaction temperature, reaction time, enzyme load, and substrate mole ratio with the purpose of producing healthy functional cooking oil for long-term dietary treatment. Lipozyme RM IM lipase-catalyzed esterification of medium- and long-chain triacylglycerols (MLCT) from glycerol and mixtures of capric and oleic acid was optimized using response surface methodology (RSM) with a five-level, four-factorial design. Reaction temperature, reaction time, and substrate mole ratio strongly affected MLCT synthesis (P < 0.01). However, enzyme load did not have a significant (P > 0.01) effect on MLCT yield. Comparison between predicted and experimental value from central composite rotatable design optimization procedures revealed good correlation, implying that the reduced cubic polynomial model with backward elimination statistically expressed the percent MLCT yield obtained. The optimum MLCT yield was 59.76% by using 10 wt% enzyme load, reaction temperature of 70°C, reaction time of 14 h, and substrate mole ratio of 3.5:1. Experiments to confirm the predicted results using the optimal parameters showed an MLCT yield of 56.35% (n = 2). The choice on the types of fatty acids used in MLCT optimization work greatly influenced the physical and chemical properties of MLCT oil produced. The refined MLCT oil characteristics study showed this oil is suitable to be used for cooking/frying purposes as a high-value added product.     

永固红F5R电泳液微胶囊的制备和表征

采用十八胺对永固红F5R进行化学修饰,以Span-80为稳定剂,四氯乙烯为分散介质,制备了分散性和稳定性良好的电泳液.以此电泳液为囊芯,脲甲醛树脂为壁材,制备了一种红色电子墨水微胶囊,研究了投料比、合成温度、酸化时间和搅拌速度等对合成微胶囊的影响.结果表明,合成的微胶囊形貌呈规则球形,表面光滑,囊壁结构致密,强度较好,包覆率达到82%,囊芯含量达到76%.永固红F5R电泳液微胶囊具有明显的电场响应行为,可以作为柔板显示器的功能材料.     

用离子交换树脂从硫脲硫酸溶液中回收金银的研究

本文从树脂选型、吸附和解吸等方面,介绍了用离子交换法从含金量较低的硫脲硫酸溶液中,回收金、银的试验研究结果。结果表明,用D61和732牌号的强酸性阳离子交换树脂,能有效地从料液中吸附金、银;用氰化钠碱性溶液作解吸剂,金的解吸率>99％,银的解吸率>70％。     

Enhancing Animal Disease Resistance,Production Efficiency,and Welfare through Precise Genome Editing

The major goal of animal breeding is the genetic enhancement of economic traits. The CRISPR/Cas system, which includes nuclease-mediated and base editor mediated genome editing tools, provides an unprecedented approach to modify the mammalian genome. Thus, farm animal genetic engineering and genetic manipulation have been fundamentally revolutionized. Agricultural animals with traits of interest can be obtained in just one generation (and without long time selection). Here, we reviewed the advancements of the CRISPR (Clustered regularly interspaced short palindromic repeats)/Cas (CRISPR associated proteins) genome editing tools and their applications in animal breeding, especially in improving disease resistance, production performance, and animal welfare. Additionally, we covered the regulations on genome-edited animals (GEAs) and ways to accelerate their use. Recommendations for how to produce GEAs were also discussed. Despite the current challenges, we believe that genome editing breeding and GEAs will be available in the near future.     

基于自由漂浮空间机器人的空间焊缝跟踪

空间机器人可以在宇宙空间自由飞行或浮游,协助或代替宇航员完成空间焊接作业。以平面自由漂浮双臂空间机器人为对象,研究了焊枪跟踪空间焊缝的位置与姿态的路径规划问题。在双臂空间机器人运动学模型基础上,对焊枪末端点速度的计算方法进行了深入讨论和分析,进而将空间机器人双臂末端点速度的求解问题定义为一个高维空间搜索问题,并采用遗传算法对其进行了优化计算,最后提出了双臂空间机器人跟踪空间焊缝的运动规划算法,并通过直线与圆弧焊缝跟踪的仿真试验进行了验证和分析。     

n-GaAs和p-GaN晶片的直接键合

采用直接键合的方法成功实现了n-GaAs和p-GaN晶片的高质量键合.扫描电子显微镜观测结果表明,键合界面没有空洞.键合前后光致发光谱测试表明,键合工艺对材料质量影响不大.室温下界面的电流-电压特性表明,键合得到的n-GaAs/p-GaN异质结为肖特基二极管并且理想因子为1.08.n-GaAs和p-GaN材料直接键合的成功对于集成GaAs和GaN材料制备光电集成器件有重要意义.     

三水碳酸镁催化酚醛聚合制备多孔炭及其性能研究

利用水合碳酸镁催化功能及易分解特性,实现间苯二酚-甲醛体系的快速凝胶,通过炭化得到孔隙发达,比表面积大的整体式多孔炭(MCM-Mg)。系统研究了原料浓度、催化剂用量、反应温度、反应时间、炭化温度以及炭化时间工艺等因素对多孔炭性能的影响。结果表明,适宜的制备条件是反应温度85℃、反应时间0.5 h、间苯二酚质量3 g、催化剂用量3 g,炭化温度900℃,炭化时间1.5 h,获得密度为1.23 g/cm³、气孔率为39.71%、收率为29.07%、比表面积为193.475 m²/g,平均孔径为22.696 nm,抗压强度为25.68 Mpa的多孔炭。该工艺具有反应时间短、成本低廉和绿色环保等优点。     

Analysis of Convective Transport of Temperature-Dependent Viscosity for Non-Newtonian Erying Powell Fluid: A Numerical Approach

Non-Newtonian is a type of fluid that does not comply with the viscosity under the Law of Newton and is being widely used in industrial applications. These include those related to chemical industries, cosmetics manufacturing, pharmaceutical field, food processing, as well as oil and gas activities. The inability of the conventional equations of Navier–Stokes to accurately depict rheological behavior for certain fluids led to an emergence study for non-Newtonian fluids’ models. In line with this, a mathematical model of forced convective flow on non-Newtonian Eyring Powell fluid under temperature-dependent viscosity (TDV) circumstance is formulated. The fluid model is embedded with the Newtonian heating (NH) boundary condition as a heating circumstance and is assumed to move over a stretching sheet acting vertically. Using appropriate similarity variables, the respective model was converted into ordinary differential equations (ODE), which was later solved utilizing the Keller box approach. The present model is validated by comparing the existing output in literature at certain special limiting cases, where the validation results display a firm agreement. The current outputs for the proposed model are shown in tabular and graphical form for variation of skin friction plus Nusselt number, velocity and temperature distribution, respectively.     

牌坊式深度指示器在无极绳连续牵引绞车上的应用

在坡度起伏不定、变化无常的长距离巷道内,绞车操作司机的视野受到很大限制,无法判断运输车辆的运行位置,不能及时主动减速或停车,存在很大的安全隐患。根据深度指示器在主提升机上的使用原理,对绞车机械传动部件进行了技术设计改造,加装了深度指示器,将其显示范围予以放大,从而解决了上述问题。经长期实践使用,装置安全可靠,经济效益显著。