中密度纤维板砂光粉的粒径分布研究

应用光散射法测量MDF砂光粉的粒径分布.结果表明,MDF砂光粉粒径分布范围较广,但多数粉尘为粒径小于50μm的细微粉尘,其中粒径小于10μm的悬浮颗粒比重为16.10％,这对砂光除尘系统的除尘器清灰和吸口效率都提出了较高的要求.粗砂和精砂粉尘大小的显著差异可能是砂光粉粒径分布曲线上出现峰肩的原因.     

论中国传统白酒的降度

本文从节约粮食、保障消费者身体健康、促进中国传统白酒更广泛地走进国际市场等几个不同方面,论述了中国传统白酒降低酒精份含量即降度的必要性。同时以消费观念的转变及行业的科技进步作为保证,论证了这种降度的可行性,并介绍了现在国内的降度趋向。提出了到本世纪末及下世纪初中国传统白酒可能达到的最佳酒度值。     

延长发酵期生产降度白酒方法的研究

本实验对各不同发酵期所生产的酒中物质含量的变化情况进行了分析研究,确定了生产低度西凤酒的发酵期可延长到20天的方法。揭示了长酵酒的香味特征及其用于白酒增香的可能性,以及发酵时间对制酒生产的影响规律。     

共振光散射法测定白酒中的微量铜

在聚乙烯醇(PVA)存在下,Cu(II)与钨酸盐及丁基罗丹明B(BRB)形成的离子缔合物在602.4 nm处产生强烈的共振瑞利散射现象,且相对于试剂空白,缔合物体系的散射光强度(ΔI)与Cu(II)质量浓度在0.02～0.50“g/25 mL范围内具有良好的线性关系,据此建立的测定Cu(II)的共振光散射法的检出限可达0.93 ng/mL,且大量存在的常见离子对Cu(II)的测定不产生干扰。本法用于白酒中铜的测定,结果满意。     

浅谈白酒降度用水的净化处理方法

概述了白酒降度用水的净化处理方法,指出各种处理方法各有特点,生产中应根据原水水质选择适宜的综合净化处理方法。结合生产实践,详细介绍了反渗透水处理方法的原理、优点及其工艺流程。     

非准透明性对动态光散射的影响

处理了单个非磁介质实壳球粒子的光散射，利用该结论与Ｙａｎ的模型对比，计算和分析了多分散非准透明粒子胶悬体的小角动态光散射（ＤｙｎａｍｉｃＬｉｇｈｔＳｃａｔｔｅｒｉｎｇ）的动态结构因子。     

胶体中动态光散射的微观机制研究

根据Brownian运动的统计特性和经典电磁场理论,详细地计算了胶体中动态光散射的自相关函数,并将所碍的若干结果应用到有外电场存在的情况中,讨论了有外电场和无外电场两种情况下相应的频谱密度的不同之处。指出所得结果可用于实验中并认为它可定量分析多分散系统。     

白酒要不要降度？

自从徽酒崛起以来,降度与不降度的问题就一直让白酒企业为难。徽酒在中高端市场的发力,其中重要一条理由就是采用较低一些的差异化度数。相关人士表示,“由于中高档白酒核心消费群体消费频度大、消费量高,这些人出于身体健康考虑,会更青睐于度数较低的白酒。”市场也证明了降度白酒拥有庞大的消费市场,近十年,一大批50度以下白酒在市场上表现优异,五粮春、口子、迎驾、高炉、洋河蓝色经典等等在市场上呼风唤雨。     

Percus-Yevick近似下硬球多元系统的动态光散射

在粒子狭多分散性的近似下,分析了同时具有粒径和光学多分散性溶液中散射光的归一化一阶振幅自相关函数g~((1))(τ),得到了K≠0情况下散射光的动态结构因子的近似解析关系式。     

单塔白酒降度工艺研究报告

国内现有白酒降度工艺据文献报导,已用于工业性生产的方法主要有四类:一,冷冻过滤法。二,吸附过滤法。三、四联柱法。四,渗析法。这四种类型工艺特点虽然各有千秋,但它们都有一个共同特征,也基于一个共同指导思想:认为白酒降度后引起白色悬浮物     

Effect of solvent and temperature on the size distribution of casein micelles measured by dynamic light scattering

The objectives of this study were to investigate the effect of the solvent on the accuracy of casein micelle particle size determination by dynamic light scattering (DLS) at different temperatures and to establish a clear protocol for these measurements. Dynamic light scattering analyses were performed at 6, 20, and 50°C using a 90Plus Nanoparticle Size Analyzer (Brookhaven Instruments, Holtsville, NY). Raw and pasteurized skim milk were used as sources of casein micelles. Simulated milk ultrafiltrate, ultrafiltered water, and permeate obtained by ultrafiltration of skim milk using a 10-kDa cutoff membrane were used as solvents. The pH, ionic concentration, refractive index, and viscosity of all solvents were determined. The solvents were evaluated by DLS to ensure that they did not have a significant influence on the results of the particle size measurements. Experimental protocols were developed for accurate measurement of particle sizes in all solvents and experimental conditions. All measurements had good reproducibility, with coefficients of variation below 5%. Both the solvent and the temperature had a significant effect on the measured effective diameter of the casein micelles. When ultrafiltered permeate was used as a solvent, the particle size and polydispersity of casein micelles decreased as temperature increased. The effective diameter of casein micelles from raw skim milk diluted with ultrafiltered permeate was 176.4 ± 5.3 nm at 6°C, 177.4 ± 1.9 nm at 20°C, and 137.3 ± 2.7 nm at 50°C. This trend was justified by the increased strength of hydrophobic bonds with increasing temperature. Overall, the results of this study suggest that the most suitable solvent for the DLS analyses of casein micelles was casein-depleted ultrafiltered permeate. Dilution with water led to micelle dissociation, which significantly affected the DLS measurements, especially at 6 and 20°C. Simulated milk ultrafiltrate seemed to give accurate results only at 20°C. Results obtained in simulated milk ultrafiltrate at 6°C could not be explained based on the known effects of temperature on the casein micelle, whereas at 50°C, precipitation of amorphous calcium phosphate affected the DLS measurement.     

丙烯酸酯皮革填充乳液的粒径及其分布

采用不同的聚合方式和预乳化工艺 ,合成了丙烯酸酯皮革填充乳液。系统研究了聚合方式、复合乳化剂的用量和配比、聚合温度、官能团单体含量和搅拌强度对丙烯酸酯共聚物乳液粒径及其分布的影响     

光散射及其在大豆蛋白粒度分析中应用

该文简要介绍光散射技术及其在粒度测试中应用,并就大豆分离蛋白样品加热前后粒度变化,应用激光光散射仪,分析大豆分离蛋白加工和热处理过程中聚集体的形成和变化。     

Heat-induced gelation of whey protein at high pH studied by combined UV spectroscopy and refractive index measurement after size exclusion chromatography and by in-situ dynamic light scattering

Summary The interactions between β-lactoglobulin and α-lactalbumin involved in gelation at 67.5 °C at high pH and low salt concentration were studied by size exclusion chromatography, followed by UV and refractive index measurements, and by in-situ dynamic light scattering. This was achieved by choosing whey protein samples with different proportions of the two proteins. The ratio of absorbance at 280 nm to the refractive index was used to demonstrate that α-lactalbumin was incorporated in aggregates and gels and drastically changed the properties of the gel, making them much more turbid than the transparent gels formed by β-lactoglobulin alone at the same pH and ionic strength. At a ratio of 1:2 for α-lactalbumin relative to β-lactoglobulin in the samples, the gel consisted of a 1:1 mixture of the two proteins. The aggregates present after 10 min of heating at 67.5 °C had molar mass of about 6.10⁶ g/mol and a radius of gyration of about 40 nm. After gel formation the field autocorrelation function could be described as a power law over many decades of lag time for all samples, demonstrating selfsimilarity of the gel structure. The only exception to this was for the gel with high content of α-lactalbumin which showed an oscillatory behaviour of the autocorrelation function. Significant amounts of glycosylated caseino-macro-peptide were observed in many of the samples at the position of β-lactoglobulin. However it did not affect gelation as it remains in solution.     

Particle size distribution of break,sizing and middling wheat flours by laser diffraction

The particle size distributions of wheat flours collected along a milling diagram were assessed. Nine wheat varieties from the genetic trait Triticum aesticum vulgare and differing in hardness were studied for two consecutive years. Break, sizing and middling flours were collected for each wheat at different stages in an experimental mill, with all the milling conditions being kept constant. The particle size distributions were measured from 1·5 to 600 μm by using a laser light diffraction apparatus. The distributions were compared by principal component analysis. The method provided a global and synthetic comparison of all the flour fractions. In the case of the soft varieties, the distributions exhibited a first mode around 25 μm, corresponding mainly to isolated starch granules. The distribution of this mode was very low or non-existent for the hard varieties. As the milling conditions were the same for all the wheats, the different proportions measured for this mode were interpreted as being directly representative of the wheat hardness. The proportion of the 25 μm mode was considered as a measure of the ability of the wheat to release starch granules and could be used to follow a grinding or milling process. © 1998 Society of Chemical Industry     

电子鼻技术对哈达山白酒中掺兑酒精的鉴别

结合主成分分析法（PCA）、线性判别分析法（LDA）和方差分析法（ANOVA）,通过单因素试验确定了样品测试时的较佳酒精 度、装样体积和装样瓶顶空生成时间分别为1.9%vol、15 mL和30 min。 并在优化参数条件下,对哈达山粮食酒和酒精酒进行鉴别。 结果 表明,采用主成分分析法及线性判别分析法,电子鼻技术可鉴别哈达山粮食酒与食用酒精含量分别为0.38%vol、0.76%vol、0.95%vol、 1.14%vol、1.52%vol、1.90%vol的酒精酒。两种分析方法相比,线性判别分析法比主成分分析法鉴别效果更好。     

激光光散射技术在食品蛋白体系中的应用

激光光散射技术是一种测量灵敏度高、时间短、测得结果可重复性较高的检测技术,被广泛应用于食品医药、化学材料、生物工程等领域。食品蛋白体系非常复杂,成分多且成分间存在强相互作用,组分分布高度不均,给食品蛋白检测带来诸多不便。将激光光散射技术应用于食品蛋白体系检测具有重要意义。本文综述了激光光散射技术的基本原理以及在食品蛋白体系中的应用,以期为建立检测食品蛋白体系中分子间相互作用力大小、颗粒大小及形状结构的检测方法提供理论依据。     

响应面法优化浓香型白酒降度除浊工艺研究

针对浓香型白酒降度过程中,会出现失光、浑浊、沉淀等问题,采用活性炭吸附过滤法进行澄清处理,并以浊度、感官评分为响应值,考察活性炭添加量、吸附时间、吸附温度3个因素及其交互作用对除浊效果的影响。结果表明,当浓香型白酒降度为38%vol时,活性炭吸附除浊的最佳工艺参数为活性炭添加量0.88‰、吸附时间24 h、吸附温度-5.0 ℃。在此条件下,平均浊度为0.22 NTU,平均感官评分为90.5分。该研究为浓香型白酒降度除浊工艺及浓香型白酒低度酒的开发提供理论依据。     

酱香型白酒降度除浊关键工艺研究

酱香型白酒逐渐由高度向低度酒发展,但酱香型白酒在降度后会出现乳白色浑浊、沉淀等现象。通过冷冻处理、活性炭吸附、玉米淀粉吸附等工艺技术对基酒进行单因素和正交试验对比,结果表明,基酒最优处理工艺为冷冻温度-6 ℃、活性炭添加量1.0‰、玉米淀粉添加量1.5‰,在此最佳工艺条件下,基酒浊度为0.10 NTU,感官评分为94.5分。