剪切稀化流体中微粒子聚集行为研究

在化工过程、生物工程等领域中,实现颗粒分离至关重要。通过整合微流控技术、高速显微图像采集技术和数字图像处理技术,探究微粒尺寸、通道流量和液相流变特性对微粒聚集的影响规律。结果表明,在剪切稀化流体羧甲基纤维素钠(CMC)水溶液中,随着通道流量和颗粒粒径增大,微颗粒聚集位置逐渐向剪切速率较高的一侧偏移;随着CMC质量分数增加,聚集位置不断向剪切速率较低的一侧偏移。利用求解的幂律型剪切稀化流体速度和剪切速率方程,结合对微颗粒的受力分析,证明稠度系数越大,聚集位置越偏向剪切速率较低处;剪切稀化特性越强,聚集位置越偏向剪切速率较高处,说明在幂律型剪切稀化流体中的黏度变化是微颗粒发生特殊迁移聚集行为的一个重要原因。     

中药不良反应的研究及对策探析

目的探讨中药不良反应的对策。方法中药的不良反应包括:变态反应,肾脏毒性,心血管系统毒性反应,肝脏毒性。其引起的主要原因为超量使用,个体差异,药物自身因素,人为因素,剂型因素。结果国家已采取成立中药不良反应监测中心等措施,对中药不良反应进行管理、监测和预防。结论中医认为病人的身体状况与正常人是存在着一定的差异,如果对症下药,可以避免大部分的不良反应。     

Recycling of CRT panel glass as fluxing agent in the porcelain stoneware tile production

In the present work, the feasibility to substitute feldspar raw material in a porcelain stoneware body with Panel Cathode Ray Tube (CRT) glass was investigated. A standard batch and a composition, where 35 wt.% Na-feldspar was substituted by CRT glass, were sintered at different temperatures in the range of 1000–1250 °C. The degree of the densification was studied by evaluation of the closed and total porosity, while the sintering rate was estimated by non-isothermal dilatometric measures. The variation of the crystalline phase composition was evaluated by XRD analysis. From the preliminary study other ceramic samples with different percentages of CRT glass (i.e. 2.5, 5 and 10 wt.%) were prepared and fired in industrial kiln. The sintering parameters, the microstructure and the mechanical properties were measured and compared with the standard composition.     

An experimental investigation of gas-liquid two-phase flow in single microchannel contactors

This paper describes two-phase flow pattern and pressure drop characteristics during the absorption of CO₂ into water in three horizontal microchannel contactors which consist of Y-type rectangular microchannels having hydraulic diameters of 667, 400 and , respectively. With the help of a high-speed photography system, flow patterns such as bubbly flow, slug flow (including two sub-regimes, Taylor flow and unstable slug flow), slug-annular flow, churn flow and annular flow were observed in these microchannels. The applicability of the currently available correlations for describing flow pattern transitions in microchannels has been examined. Generally, the predicting performance of these correlations deteriorates as the channel diameter further reduces. Toward solving this discrepancy, an empirical correlation based on the superficial Weber numbers was developed to interpret the transition from Taylor flow to unstable slug flow in three microchannels. Taylor bubble formation process in microchannels was found to be in the squeezing regime at lower superficial liquid velocities (Ca ranging from 0.0019 to 0.029) while the transition to the dripping regime was observed at the highest superficial liquid velocity of 1.0 m/s. Lengths of Taylor bubbles formed in the squeezing regime can be well represented by the scaling relation proposed by Garstecki et al. [Formation of droplets and bubbles in a microfluidic T-junction—scaling and mechanism of break-up. Lab on a Chip, 6, 437-446]. For flow patterns including slug-annular flow, annular flow and churn flow, a simple analysis based on the separated flow model has been performed in order to reveal the observed effect of the superficial liquid velocity on two-phase frictional multiplier in the present microchannels. Then, reasonable correlations for the prediction of two-phase frictional pressure drop under these flow patterns were suggested.     

Optimization of wastes content in ceramic tiles using statistical design of mixture experiments

Mineral extraction and processing industries have been cited as sources of environmental contamination and pollution. The inclusion of wastes into productive cycles represents an alternative form of restoration, which is interesting from both environmental and economic standpoints. In this work, the development of ceramic tile formulations containing kaolin processing and granite sawing wastes was investigated using the statistical design of mixture experiments methodology. Ten formulations using the raw materials, red clay, kaolin processing and granite sawing wastes, were selected and used in the mixture design. Test specimens were fired and characterized to determine their water absorption, linear firing shrinkage and modulus of rupture. Regression models were calculated, correlating the properties with the composition. The significance and validity of the models were confirmed by statistical analysis and verification experiments. The regression models were used to optimize the waste content in ceramic compositions. The results showed that formulations containing up to 62% of waste could be used in the production of ceramic tiles.     

慢性结肠炎中药保留灌肠的护理对策

目的探讨结肠透析机清洗结肠后,进行中药汤剂保留灌肠治疗慢性结肠炎的护理对策。方法随机将慢性结肠炎病人192例分成2组,治疗组98例,对照组94例,治疗组先采用透析机对结肠进行充分清洗。对照组采用传统手工清洁浣肠后用同样的中药汁200～250mL进行保留灌肠。结果治疗组82例症状完全缓解,随访半年无复发,14例临床症状部分缓解,1例症状未缓解。对照组56例症状完全缓解,半年以后无复发,28例症状部分缓解,10例症状未缓解,2组均无并发症。结论结肠透析机清洗结肠配合中药汤剂保留灌肠治疗慢性结肠炎,疗效明显好于传统的中药汤剂灌肠,且复发率大为降低,经济安全。     

分子振动光谱在中药现代化中的应用

通过近些年来利用分子振动光谱及其与计算机辅助技术(二维相关红外光谱、化学计量学、模式识别和人工神经网络等)相结合用于中药的真伪鉴别、质量控制、稳定性预测和配方工艺优化等方面的研究,阐明分子振动光谱在中药现代化中的作用及应用前景。     

数码辅助方法在毛细管流变仪测量粘度的应用

讨论了传统流变仪测量粘度上存在的问题，提出了改进的方案测量粘度，以减少误差。试验方案主要体现在用数码方法采集数据。     

Survival of Listeria innocua in Minas Traditional Serro cheese during ripening

Cheese produced with raw milk can be a risk to consumer health. It is known that lactic acid bacteria present in raw milk and in natural starters can produce antimicrobial compounds against some foodborne bacteria. This work aimed to evaluate the survival of Listeria innocua in Minas Traditional Serro cheese during cheese ripening. The cheeses were inoculated with 10¹, 10² or 10³ CFU mL⁻¹ of the bacterium and were analyzed for 60 days of ripening at 30 °C. It was observed that the time and the dose of bacteria inoculated affected (p < 0.05) the survival of L. innocua. Even when the lowest dose was inoculated, at the end of the 60 days, approximately 10² CFU mL⁻¹ of L. innocua was detected in the cheese. The lactic acid bacteria present in the milk and in the natural starter were not sufficient to guarantee the absence of L. innocua in Minas Traditional Serro cheese even after 60 days of storage, as is required by Brazilian legislation.     

中日传统家具装饰五金的图案与题材

传统家具五金配件作为古典家具结构与装饰艺术中的一个重要组成部分,是体现其风格特征的重要特点之一。它们种类繁多,工艺考究,用处很广,造型也很丰富,为传统家具增添了不少光彩。中国与日本的传统家具五金配饰,各有其精致之美,本文对二者丰富的图案题材进行了浅析。