液体显白剂的研制和应用

对纸张进行增白的主要途径是添加荧光增白剂,然而纸张的视觉白度效果不仅仅取决于纸张亮度,纸张的色相也起着很大的作用。在同样亮度下,紫白或蓝白色相的纸要比黄色色相的纸视觉白度高许多,所以紫白和蓝白就成为纸张调色的主要方向。首先,对未使用荧光增白剂的纸浆用蓝色和紫色染料进行调色研究其增白效果,结果见表1.首先加入0.05%的液体荧光增白剂,再加入活性蓝和活性紫调色,结果见表2.由表1和表2可得,对未增白纸浆用活性蓝和活性紫调色,抄片白度略有提高,并且用活性紫调色后的抄片看上去较亮,稍显白;对经增白后的纸浆调色,抄片白度变化不…     

杨木化机浆使用荧光增白剂的增白性能研究

对比了液体荧光增白剂（OBA）及固体荧光增白剂（VBL）对杨木化机浆的增白效果,研究了表面喷淋及浆内添加荧光增白剂的增白效果。结果显示,OBA对杨木化机浆的增白效果明显好于VBL的;表面喷淋荧光增白剂的增白效果优于浆内添加的;OBA对染色和返黄后杨木化机浆的增白效果不同,表面喷淋0.5%的OBA,染色后白度75.8%的杨木BCTMP的白度提高11.2个百分点,白度达87.0%,与未染色的杨木BCTMP相比,增白后两者的白度仅相差0.7个百分点,而白度为75.1%的返黄杨木BCTMP的白度只增加4.2个百分点,白度为79.3%。     

基于荧光增白织物的白度公式评价

为了探求更符合视觉白度的客观评价公式,采用成对比较法心理物理学实验,分析了7个主要白度公式对荧光增白织物的预测性能。从自制的100个白色荧光织物中挑选22个样品(含6个CIE白度范围外样品),招募17名三色视觉正常者开展白度视觉评价实验,利用数理统计方法处理视觉评价数据,并与Ganz、CIE、Uchida、W_(uv)、W_(LAB)、Hunter和C/V等7个白度公式的计算值做统计比较。结果显示:评价CIE白度范围内样品时,Hunter公式最好,其他依次为C/V、CIE、Uchida、W_(uv)、Ganz、W_(LAB);评价CIE白度范围外的样品时,Hunter依然最好,其他依次为C/V、W_(LAB)、W_(uv)、Uchida、CIE、Ganz。综上,对于测试的荧光增白织物,Hunter白度公式的评价效果最佳。     

织物荧光增白与色谱分析

本文从人眼对织物白度的分辨和利用分谱测色仪对荧光织物和一般白色体的色谱分析,论述荧光增白织物的光谱特征和对人眼白度视觉的影响因素。同时,推荐一种既能作为相对比较,又能有助于工艺改进的白度测量方法。     

荧光增白剂对提高纸浆白度的影响

本文对稻草ＡＳ－ＡＱ浆加入荧光增白剂白度的提高进行了研究。试验表明：在同等条件下，随着增白剂用量的增加，纸页白度提高，一般认为增白剂用量在０．１２￣０．１６％为宜。增白剂在ｐＨ７．１时施用，增白效果最显著。增白剂的使用随浆料浓度的提高，对白度的提高明显。浆料的起始白度越高，加入增白剂后的增白效果越显著。     

液体荧光增白剂和粉状荧光增白剂增白性能的比较试验

使用液体荧光增白剂PL-1和粉状荧光增白剂VBL在混合纸浆中进行增白性能比较试验。结果表明:液体荧光增白剂PL-1提高了纸张的白度,最高达到97.06%ISO,且成本低,具有广泛的推广应用价值。     

影响荧光增白剂使用效果的几个因素

荧光增白剂是造纸工业中使用最早而又较为普遍的一种光学增白助剂 ,纸厂在使用过程中积累了不少经验 ,但如何正确而有效地使用 ,仍为许多造纸工作者、生产者所关注的问题 ,因此进一步了解影响荧光增白剂在纸浆中增白效果的理化因素是很有必要的。１增白剂的用量随着增白剂用量的增加 ,纸浆增白幅度亦提高 ,但单位用量所增白度下降。根据化工部标准“ＨＱＺ -３８２ -８３荧光增白剂”的规定 ,ＶＢＬ的返黄程度为用量０ ５ % ,可见用量不宜超过０ ４ %。另据研究 ,增白剂成本不是随用量成比例增长 ,而是成倍甚至数倍剧增。根据纸张不同白度的…     

对荧光增白剂VBL的认识

1、荧光增白剂VBL的增白机理 荧光增白剂被吸附在纸浆纤维上,在日光照射下,增白剂能吸收紫外光,将其转变为可见光而辐射出蓝色荧光,正好可以补偿纸浆中的淡黄色,相加而成白光,这样,纸浆抄成纸张后,可见光总反射率增大,从而提高了纸张亮度,增加了纸张的视觉白度。     

“绵阳同成智能装备股份有限公司成都志豪纸业4060/600 生活用纸纸机及竹浆原纸现场推广会暨四川省生活用纸行业 2015一季度生产经营总结会”在成都大邑召开

Sappi北美公司在2015年3月中旬宣布将 Opus 平板涂布纸白度提高到94％，提高了产品的白度、色调 一致性和挺度，降低了荧光增白性。     

纺织品中荧光增白剂安全性的探讨

文章介绍了荧光增白剂的增白原理及其在纺织品上的应用,并探讨了其安全性,指出应对纺织品中荧光增白剂的安全性进行深入研究,制定相关标准并严格执行,避免其对使用者产生不良影响。     

基于心理物理学实验的非荧光织物白度公式评价

为给非荧光纺织品白度评价优选出最接近人眼色觉的白度公式,采用白色辨识实验从自制非荧光织物中挑出白色样品,再分别挑选28个和85个样品开展成对比较法和类别判定法2种心理物理学实验,处理1万余个视觉评价数据,与9个白度公式的计算白度值作对比和统计分析,综合评价白度公式的预测性能。结果显示:以成对比较法评价白度公式时,亨特2(Hunter2)白度公式效果最好;以类别判定法评价白度公式时,Hunter2白度公式依然最好;2种评价方法结果一致,对于本文所用非荧光织物,原适用于评价荧光织物的Hunter2白度公式与人眼色觉的一致性最优。     

IDENTIFICATION OF SENSORY COLOR OPTIMA OF STRAWBERRY YOGURT

Commercially available strawberry yogurts were subjected to preference ranking done by an untrained panel and to instrumental color analysis. Spectral reflectance data and color values expressed in the CIELAB system revealed different color properties of the yogurts, mainly with respect to the hue angle determining whether a product is, e.g., dominantly red or dominantly orange. Sensory evaluations resulted in three groups of products being significantly different from each other with respect to their preference patterns. The tomato color index originally proposed for measuring the ripening index of tomatoes appeared to be useful to reduce 3‐dimensional yogurt color values to one dimension and to construct a function of preference ranks versus instrumentally measured data.     

纺织品视觉遮蔽性评价指标比较研究

对常见的纺织品光学性能的一些表征指标,包括白度、可见光波段平均透射率、明度、透明度及不透明度等进行对比,分析探讨其在表征纺织品视觉遮蔽性上的适用性和可行性。结果表明：织物为浅色或白色时,其视觉遮蔽性可采用白度表征;当织物纤维种类相同时,则可以采用明度;550nm波长处透射率以及可见光波段平均透射率与不透明度相关性都较好,在没有相关标准的前提下,均可以用来表征各类织物的视觉遮蔽性。     

增白剂在涂料制备中的用量及对白卡纸返黄的研究

选用六个不同厂家的四磺酸液体荧光增白剂进行白卡纸涂布研究,综合验证了荧光增白剂在涂料中的添加量对白卡纸白度及返黄程度的影响。结果表明：FWA的用量为0．6％至0．8％时,成纸白度最高,返黄值最低。     

打浆度软测量信号中有色噪声的白化及滤除

针对打浆度软测量过程中有色噪声对实际打浆度信号造成的混叠干扰,提出一种新型的信噪分离和消噪的方法。由于软测量噪声不是白噪声信号,因此首先建立噪声的AR模型并根据模型对噪声信号进行白化处理,最终采用相关分析的方法完成噪声的滤除。将该方法试运行于造纸生产线打浆控制系统中,可达到较高的打浆度软测量精度。     

Effect of pasteurization and fat,protein, casein to serum protein ratio,and milk temperature on milk beverage color and viscosity

Our goal was to determine the effect of pasteurization-homogenization, fat and protein concentration, proportion of milk protein that is casein and serum protein, and temperature on sensory and instrumental measures of viscosity and color of milk-based beverages. A second goal was to use instrumental measures of whiteness and yellowness to predict sensory measures of whiteness and yellowness. A complete balanced 3 factor (fat, true protein, and casein as a percentage of true protein) design was applied with 3 levels of fat (0.2, 1.0 and 2.0%), 4 levels of true protein (3.00, 3.67, 4.34, and 5.00%) within each fat level, and 5 levels of casein as a percentage of true protein (CN%TP; 5, 25, 50, 75, and 80%) within each protein level for beverage formulation. Instrumental color and viscosity, and visual sensory color analyses were done on each beverage formulation. For unpasteurized beverages across 3 fat levels (0.2, 1, and 2%), changes in CN%TP had the largest effect on L values, sensory whiteness, opacity, color intensity, and yellowness, whereas changes in fat concentration had a stronger influence on a and b* values. Increasing CN%TP from 5 to 80% increased L values, sensory whiteness, and opacity, and decreased sensory color intensity and yellowness. The a and b* values increased with increasing fat concentration. For unpasteurized milk protein beverages within each fat level, variation in CN%TP dominated the changes in L values, sensory whiteness, and opacity, and decreased a and b* values, sensory color intensity, and yellowness. The effect of heat (pasteurization and homogenization) and its interaction terms had the second largest effect on color of milk protein beverages with respect to instrumental color data and sensory appearance attributes. Heat increased L values, sensory whiteness, and opacity, and decreased a and b* values, sensory color intensity, and yellowness. Increases in temperature decreased instrumental viscosity and changes in protein concentration and CN%TP had a greater effect on instrument viscosity data within each temperature (4, 20, and 50°C) than fat. Sensory perception of yellowness was not highly correlated with b* values. Multiple linear regressions of L, a, and b* values produced more robust predictions for both sensory whiteness and yellowness than simple linear regression with L and b* values alone, and may be a useful instrumental approach for quality control of sensory whiteness and yellowness of milk protein beverages.     

Color of Nonfat Fluid Milk as Affected by Fermentation

Nonfat milks inoculated and fermented with exopolysaccharide and non-exopolysaccharide producing cultures were compared to nonfat, 2% milkfat and whole milk with instrumental and sensory color measurements. L-(whiteness) and a- values (red/greeness) for fermented nonfat milks were higher than nonfat milk. No differences in L-, a-, or b- values (yellow/blueness) were found between milks fermented with exopolysaccharide as compared to non-exopolysaccharide producing strains. A trained sensory panel scored edge and center whiteness of fermented milks whiterthan nonfat milk. Milks fermented with exopolysaccharide producing cultures were scored higher than non-exopolysaccharide producing cultures with respect to edge and center whiteness. Fermentation and exopolysaccharide production may increase visual perception of whiteness in milk.     

白酒的色泽小议

白酒的正常色泽为无色透明，允许的色泽为微黄色透明。白酒的色泽与白酒的香型有一定的关联性。影响白酒色泽的原因主要有：酿酒的原料、设备、贮酒的容器等。如果酒中杂醇油含量较高，加之酒度较低、室温较低时，酒会呈现乳白色。     

基于汉风色典的不同色差公式的色差均匀性

为给纺织行业在纺织品贸易和质量控制等方面优选色差公式提供参考,研究了3个重要的和1个最新色差公式的色差均匀性,借助国际上色样多、视觉等距性好的汉风色典,利用X-Rite测色仪测试近2万个色样的色度参数,然后分别从向度、彩度、浓度3个方向选取3万多对相邻色样,采用MatLab编程计算4种色差并统计分析其均值、不匀率和性能因子。结果表明:不同方向不同评价指标所得结果不尽相同;在色差均匀性方面,CAM16-UCS最好,CIEDE2000_(2∶1∶1)略优于CMC_(2∶1),且二者明显优于CIELAB;在色差大小方面由小到大依次为CIEDE2000_(2∶1∶1)、CMC_(2∶1)、CAM16-UCS、CIELAB。     

CRISPNESS AND CRUNCHINESS JUDGMENT OF APPLES BASED ON CONTACT ACOUSTIC EMISSION

Contact acoustic emission (AE) measurement, together with a puncture test, were used to evaluate the crispness and crunchiness of three apple cultivars. A storage program was used to induce changes in apple crispness and crunchiness. The instrumental measurements were compared with the results of sensory evaluation.
It was found that crispness and crunchiness could be evaluated instrumentally by measuring firmness, AE events, mean AE amplitude or the product of AE events and mean AE amplitude. For one cultivar, however, firmness was not correlated with any sensory attribute. Generally, the best correlation with sensory attributes was found for the exponential value of AE events. Contact AE allows the measurement of sensory crispness or crunchiness for a given apple cultivar or independently for any apple cultivar. Contact AE can be considered as a useful method for the evaluation of sound properties of wet-crisp foods.

PRACTICAL APPLICATIONS

Contact acoustic emission method can be used for instrumental evaluation of crispness and crunchiness of apples. The method allows more accurate evaluation of these attributes than firmness measurement. There is a chance to extend the application to other wet-crisp foods and to use the method together with other destructive tests, like texture profile analysis or single edge notched bend.