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1.
本文找出了EBT指示剂法存在问题的原因。提出了用K-B指示剂法测定水的总硬度,滴定终点指示剂变色敏锐,颜色稳定。测定结果的精密度,准确度较高。是一种较为理想的测定方法。  相似文献   

2.
本文首次研究了 DCB—DNA 作为钙镁络合滴定指示剂的条件及应用于水泥、高炉矿渣和白云石等试样中氧化钙、氧化镁含量测定的可能性。研究结果表明:在 PH=10.0的氨性缓冲溶液中,加入0.1%的 DCB—DNA 作指示剂,以0.02mol·1~(-1)的 EDTA 标准溶液进行滴定,溶液颜色由蓝色变为红色。利用乙酰丙酮作掩蔽剂可测定钙镁混合样中钙含量。此指示剂终点颜色变化敏锐,准确度高,选择性好,是络合滴定钙镁的优良指示剂。  相似文献   

3.
维多利亚蓝B作为酸碱指示剂的应用研究   总被引:1,自引:0,他引:1  
利用维多利亚蓝B在不同的pH值下显示不同的颜色,测定出了不同pH值下相应的最大吸收波长和最大吸收波长下的摩尔吸收系数.测定出了维多利亚蓝B颜色由蓝色型体变为红色型体的酸碱解离常数为pkα8.25,作为酸碱指示剂变色点的pH=8.25.利用维多利亚兰B作为酸碱指示剂进行酸碱滴定,与酚酞指示剂对照,无显著性差异,滴定得到满意的结果.  相似文献   

4.
概述了以甲基橙为指示剂,用氯化锡还原三价铁离子,再以二苯胺磺酸钠作指示剂,以重铬酸钾标准溶液滴定测定微生物冶金浸出液中的全铁的方法。在测定时,有时终点颜色得不到正常的紫色,对此现象进行了探讨并提出了一些解决方案。  相似文献   

5.
酸碱指示剂一般是弱的有机酸或有机碱。其共轭酸碱具有不同的结构,且颜色不同。当溶液的pH改变时。共轭酸碱相互发生转变,从而引起溶液的颜色发生改变。本利用植物花、茎、叶、根或果实自制酸碱指示剂并测其变色范围,来进行研究性学习。  相似文献   

6.
氨基酸分子结构中,既含有酸性的羧基,又含有碱性的氨基,属两性化合物。在实验中,常将氨基酸溶液加到强酸(强碱)稀溶液中,根据溶液中酸碱指示剂颜色的改变来证实氨基酸同时具有碱性和酸性。在见到的实验教材中,该实验选用的酸碱指示剂是甲基橙和酚酞,但用这两种指示剂实验现象并不明显,效果较差。若要使指示剂的颜色能有稍明显的变化,则须大大超过实验教材述及的氨基酸溶液的加入体积。下面以甘氨酸为例,分析氨基酸溶液须超量加入的原因。  相似文献   

7.
无机化学中经常要用到pH值的测定,测定某一溶液的pH值,常见的方法有酸碱指示剂的使用、pH试纸的使用以及酸度计的使用,下面分别谈谈它们在无机化学实验中的应用。1 酸碱指示剂酸碱指示剂是一种借助自身颜色变化来指示溶液pH值改变的化学物质,酸碱指示剂一般是复杂的有机分子,并且都是弱酸、弱碱或两性物质.每种酸碱指示剂都有一定的变化范围,同一种指示剂在酸  相似文献   

8.
本文利用胺滴定法在H0为+5.0--8.2范围的环已烷溶液中观察吸附的哈迈特指示剂的颜色变化,选用PKa值不同的向种指示剂,测出不同酸强度下的酸量而作出酸强度分布曲线,探讨了其规律性。  相似文献   

9.
水硬度测定实验方法改进   总被引:1,自引:0,他引:1  
研究了在阳离子表面活性剂存在下,以二甲酚橙为指示剂测定水硬度的新方法,该方法终点颜色变化敏锐,结果令人满意。  相似文献   

10.
利用胺滴定法在H0为+5.0--8.2范围的环已烷溶液中观察吸附的Hammett指示剂的颜色变化,选用PKα值不同的几种指示剂,测出不同酸强度下的固体催化剂酸量,作出酸强度分布曲线,探讨了其规律性。  相似文献   

11.
基于颜色图直方图的监督颜色恒常性算法   总被引:7,自引:0,他引:7  
在颜色物体识别等应用中,获取不随光照变化的颜色恒常性特征是问题的关键。监督颜色恒常性方法,即通过在环境中放置校正用的颜色片来计算并消除光照的影响,由于其简单方便而得到了广泛的应用。在本文中,基于对直方图光照不变量的分析,提出了一种新的监督颜色恒常性算法。该算法与传统算法相比较,不需要知道颜色片的反射率和成象系统的通道响应,从而大大简化了实现的要求。文中给出了算法的基本思想,并对实验结果进行了分析。  相似文献   

12.
彩色全息图的制作是当今全息显示技术中的一个重要研究内容,对全息显示的发展有重要的意义,彩色全息图的制作方法较多,为了提高彩色全息图的质量,提出了用衍射分色法制作彩色全息图,它是通过使用三色光栅,把一张彩色透明片的红、绿、兰信息编码记录在一张黑白胶片上,用单色激光同时再现出所记录的3种颜色的光强分布并将它们记录在一张全息片上作成彩色全息图,该方法的显著优点是制作过程中无须制作3张分色掩膜信息的全息图,改进了3分色法的对准问题,使制作的全息图衍射效率高,再现像的色彩清晰,明亮,还原性好。  相似文献   

13.
Long-range colour-generating interactions across the retina   总被引:1,自引:0,他引:1  
E P?ppel 《Nature》1986,320(6062):523-525
The existence of colour-generating interactions across the corpus callosum has recently been suggested from observations with a 'split-brain' patient, thus indicating long-range colour computations at the cortical level. Observations on induced colours described here suggest long-range colour computations at the retinal level. If a white surface surrounded by a particular colour is fixated for some time, the resulting after-image has two colours: the surround appears in complementary colour, whereas the white centre takes on the colour of the surround. The question of whether such colour induction is located in the retina or more centrally was tested in a brain-injured patient with hemianopia. It could be demonstrated that areas of the visual field that are no longer represented in the geniculo-striatal pathway still contribute to colour induction, suggesting that colour induction is a retinal phenomenon.  相似文献   

14.
研究了历代青花瓷色调的变化,经研究发现,历代青花色调的变化与色料中着色元素钴、铁和锰的含量和比例密切相关;其次,色料中氧化铝的含量对历代青花色调也有影响,氧化铝含量低于18%~20%时,色料易流散,高于18%~20%时,花纹较清晰;青花瓷烧成温度应在1 300~1 320℃,气氛为还原气氛;胎釉应与色料的烧成温度、气氛和升温速度相适应。  相似文献   

15.
该文对双谱假彩色微光电视系统的原理进行论述,探讨了实现双谱假彩色微光电视系统的有关技术。双探测技术是这种彩色微光技术的重要组成部分和理论基础,其关键是根据夜天光辐射以及景物夜晚光谱反射特性,选择合适的对比度转换点位置,分割有效光谱两部分;彩色最佳逼近技术,就是研究如何选择这一对比度转换眯位置和适当算法,才能使双谱彩色图象具有最佳的分辩率和图象探测率,最后给出系统实现方法、实验结果及分析。  相似文献   

16.
Polymorphism of the long-wavelength cone in normal human colour vision   总被引:5,自引:0,他引:5  
J Neitz  G H Jacobs 《Nature》1986,323(6089):623-625
Colour vision is based on the presence of multiple classes of cone each of which contains a different type of photopigment. Colour matching tests have long revealed that the normal human has three cone types. Results from these tests have also been used to provide estimates of cone spectral sensitivities. There are significant variations in colour matches made by individuals whose colour vision is classified as normal. Some of this is due to individual differences in preretinal absorption and photopigment density, but some is also believed to arise because there is variation in the spectral positioning of the cone pigments among those who have normal colour vision. We have used a sensitive colour matching test to examine the magnitude and nature of this individual variation and here report evidence for the existence of two different long-wavelength cone mechanisms in normal humans. The different patterns of colour matches made by male and female subjects indicate these two mechanisms are inherited as an X-chromosome linked trait.  相似文献   

17.
The aim of this study explored the importance of colour application on clothing and investigated whether there is a preference of colour on clothing among children under hospital environment. A modified colour associated test based on the Luster Color Test was used to carry out the survey. Fifty child patients aged four to sixteen were asked to look at two specially designed colour cards and to name their preferences and associations on each of the colour.  相似文献   

18.
本文提出不必先拍摄主全息图而只利用彩色照片或图片的分色片和单波长激光,根据加色法直接拍摄出能白光再现的真彩色彩虹全息图,这种一步法适宜批量生产出低噪声、彩色还原性好,高清晰度的真彩色彩虹全息图。  相似文献   

19.
Dynamic coding of behaviourally relevant stimuli in parietal cortex.   总被引:12,自引:0,他引:12  
Louis J Toth  John A Assad 《Nature》2002,415(6868):165-168
A general function of cerebral cortex is to allow the flexible association of sensory stimuli with specific behaviours. Many neurons in parietal, prefrontal and motor cortical areas are activated both by particular movements and by sensory cues that trigger these movements, suggesting a role in linking sensation to action. For example, neurons in the lateral intraparietal area (LIP) encode both the location of visual stimuli and the direction of saccadic eye movements. LIP is not believed to encode non-spatial stimulus attributes such as colour. Here we investigated whether LIP would encode colour if colour was behaviourally linked to the eye movement. We trained monkeys to make an eye movement in one of two directions based alternately on the colour or location of a visual cue. When cue colour was relevant for directing eye movement, we found a substantial fraction of LIP neurons selective for cue colour. However, when cue location was relevant, colour selectivity was virtually absent in LIP. These results demonstrate that selectivity of cortical neurons can change as a function of the required behaviour.  相似文献   

20.
In colour measurement ralated industry, reflectance spectrophotometer is the one of the popular measuring machine for measuring colour and quality control. Colour communications is frequently confusing. This is because the colour appearance is subject to the influence of at least three different phenomena: the light source, the object and the visual system. The variation in either the radiant quantity or the spectral distribution of the source can alter the observed colour. Because of this reason, the objective quantitative tool, colour measurement equipment and communication method; become more important in evaluating of the colour. In fact, based on the advanced in computer system and electronic device, the colour measurement becomes more and more accuracy, especially in spectrophotometer measurement. In this paper, we will focus on the review of modern spectrophotometers in coloration industries.  相似文献   

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