酸性添加剂改善酸敏变色记录材料稳定性能的研究

为了提高酸敏变色记录材料的图象稳定性能,进行了添加苯酚、水杨酸、乙酸、苯甲酸等酸性添加剂的试验。其光谱特性显示,加入适量的苯酚、水杨酸添加剂后,图象的稳定性能得到改善,而乙酸、苯甲酸添加剂却不能起到这种作用。试验中采用核磁共振技术作了检测,在加入苯酚添加剂时有氢质子释放,抑制了醌式结构向初始状态的回复,改善了图象的稳定性能。     

酸敏变色记录材料的光谱特性及其光量子产率

本文研究了由偏二氯乙烯-丙烯酸甲酯共聚合物(VdCl₂-MA)和五甲氧基红指示剂组成的酸敏变色记录材料的光谱特性,测定了其光分解量子产率.通过添加光敏剂使原来只有在254nm紫外光下曝光才能发生光分解反应的酸敏变色材料在35nm紫外光下曝光也可发生光分解而变色.酸敏变色材料在254nm处紫外光曝光量子产率为0.032-0.020;在35nm处紫外光曝光量子产率为0.110-0.034.光敏剂的加入使酸敏变色材料量子产率提高了2-4倍.     

酸敏变色记录显示片再生方法的研究

我们进行了酸敏变色记录显示片(简称酸敏片)重复使用的试验,并对其实用性在实验中给予证实。实验结果表明:酸敏片经曝光后,由于释放 HCI 酸源使酸性指示剂变色形成图像,通过还原酸性指示剂,使曝     

酸敏变色片——一种新辐射敏感材料

随着电子技术及半导体工业的迅速发展,出现了许多记录电子束的材料。除卤化银材料外,还有光刻胶,热塑材料,液晶等。卤化银材料与光刻胶虽有较高的灵敏度及分辨力,但需要湿法显影、定影,暗室操作,使用不方便。液晶虽手续简单,能及时显示,但分辨力低。且不能贮存图像。热塑材料虽能实时显示和记录图像,但需要比较复杂的纹影光学系统,对记录材料的光学质量要求很高,难于达到。近年来我们研制的酸敏变色片则具有多种优点。它具有较高的灵敏度,达7.2×10~(-3)焦耳/cm~2,分辨力不低于500线对/mm,无     

四苯基卟啉变色酸敏片

卟啉自由碱通常是紫或紫红色固体,遇酸则变成绿色,对光敏感。人工合成的卟啉最简单的是四苯基卟啉(H_2TPP)。美国专利曾将卟啉类化合物作为光氧化成象体系的增感剂。我们试图将H_2TPP作为VMD片(一种新型非银盐成象体系)的增感剂,未获成功。     

红敏光致聚合物全息记录材料噪声研究

本文从几个不同的方面研究了明胶全息记录材料体系(PPG)产生噪声的原因,并研究了单体丙烯酰胺(Am)与交联剂亚甲基双丙烯酰胺(B.Am)浓度比值、三乙醇胺(TEA)浓度、曝光量、后处理条件等对噪声的影响.结果表明:单体/交联剂比例为30:1时,体系噪声有所降低.三乙醇胺浓度对体系噪声影响较大,适宜浓度为1%.后处理工艺中,水洗温度对噪声有直接影响,最佳温度为28℃.     

变色酸双偶氮胂酸型试剂与稀土元素的显色反应

本文综述了作者近年来对变色酸双偶氮胂酸型试剂的研究工作,包括显色反应的灵敏度、选择性、类型、机理、多元络合物的形成反应,及其在分析中的应用。用量子化学和反应动力学法研究了这类试剂在速差动力分析法中应用的可能性,对已用于光度分析的新变色酸双偶氮胂酸型试剂进行了概括。     

镓(Ⅲ)与变色酸荧光反应及其应用研究

在pH＝4.4的乙酸-乙酸钠缓冲体系中,镓(Ⅲ)与变色酸反应生成新的荧光物质,在λex/λem＝242/370 nm,测得荧光强度增量△F与镓(Ⅲ)的含量在0～10 μg/25mL范围内服从比耳定律.探讨了荧光增强的条件.该方法用于样品分析的线性方程为:△F＝26.80c(μg/25mL)+0.011,相关系数r＝0.9991.测定煤样和煤矸石中镓含量分别为6.29 mg/kg和10.97 mg/kg,加标回收率在96.8%～103.5%之间,相对标准偏差＜5.0%(n=4),与分光光度法相比,结果满意.     

7-苯基偶氮-变色酸与蛋白质的显色反应研究

研究了蛋白质与 7-苯基偶氮 -1 ,8-二羟萘 -3 ,6-二磺酸的显色反应。在 p H2 .7的缓冲溶液中 ,7-苯基偶氮 -1 ,8-二羟萘 -3 ,6-二磺酸与蛋白质形成红紫色复合物 ,λmax为 564 nm,ε为 1 .3× 1 0 5L· mol- 1· cm- 1,线性范围为 6.6～ 1 3 2 mg/ L。实验证实7-苯基偶氮 -1 ,8-二羟萘 -3 ,6-二磺酸与蛋白质的作用符合 Pesavento模式。所提出的方法不经任何预处理可直接测定血清和花生中的蛋白质     

变色酸双偶氮羧酸型衍生物与稀土元素显色反应的研究

本文设计合成了十种双偶氮羧酸型试剂,较详细地研究了它们与稀土元素的显色反应,初步总结出这类试剂分子中分析功能团的位置以及助色团的性质和位置的改变与分析性能之间的内在联系。探讨了这类试剂与稀土元素显色反应中所存在的倒序现象和酸效应的可能原因。     

A STUDY OF THE SAFRANINE-ASCORBIC ACID PHOTOCHEMICAL REDOX REACTION

Abstract— Flash-photolysis of safranine in deoxygenated 5 per cent aqueous pyridine produces a transient bleaching, which disappears by a second order process. Very probably this transient species consists of a pair of radicals or radical ions and not of the safranine in the triplet state. These radicals are also produced in chlorophyll sensitized reactions. Present results combined with previous work by us[I] indicate that the chlorophyll sensitization of safranine bleaching involves the formation of these radicals.
The direct photochemical reduction of safranine to its leuco form occurs through the intermediate formation of the radicals. The appearance and disappearance of these radicals is fast compared to the role of photochemical formation and thermal disappearance of leuco safranine. Ascorbic acid influences but is not essential to the photo-bleaching of safranine in 5 per cent aqueous pyridine. An increase in ascorbic acid concentration increases the steady-state yield of the radicals but decreases the steady-state yield of the leuco safranine. In the absence of ascorbic acid or other added substance, safranine photobleaches irreversibly in deoxygenated 5 per cent aqueous pyridine. A plausible mechanism is proposed in explanation of the direct photochemical reduction of safranine.     

A FLASH PHOTOLYSIS STUDY OF INTERMEDIATES IN PHOTOCHEMICAL REACTIONS OF CHLOROPHYLL

Abstract— The photochemical reactions of chlorophyll intermediates in vitro have been studied by the flash photolysis method. The flash excitation of pigment solutions has been shown to involve the population of a chlorophyll triplet state where the oxidation-reduction processes occur. The mechanism and kinetics of pigment triplet decay have been investigated from 20°to — 50°C and the ability of chlorophyll molecules to carry out triplet-triplet energy transfer has been established. The latter phenomenon has been used to show up the role of chlorophyll triplets in the reversible photooxidation reaction with P -quinone. There have been studied initial products of pigment photoreduction with ascorbic acid and phenylhydrazine. Experimental data of the mechanism of the initial oxidation and reduction in chlorophyll photosensitized reactions have been analysed. There have been also obtained the differential spectra of chlorophyll triplets and radicals. A calculation has been made of rate constants for a few elementary reactions.     

烧成温度对气敏材料性能的影响

选用SnO₂-ZrO₂和SnO₂-ThO₃体系作为气敏材料,研究了烧成温度对材料结构和粒度的影响。分别用以上体系制成气敏元件,研究了烧成温度对气敏材料的灵敏度和选择性的影响,结果发现,在本实验条件下,烧成温度不但影响材料的灵敏度,对材料的选择性也有很大的影响。     

PHOTOCHEMICAL REACTIONS OF AZIDOCOUMARINS

Abstract— Photochemical reactions of 6-azidocoumarin and 7-azido-4-methylcoumarin in the presence of secondary amines have been investigated for their potential applications in photoaffinity labeling. It was found that the singlet nitrene generated from 6-azidocoumarin isomerized to a dehydroazepine intermediate that reacted with an amine to yield two isomeric adducts. Photolysis of 7-azido-4-meth-ylcoumarin, in contrast, gave a triplet nitrene that abstracted hydrogen atoms from secondary amine molecules to form 7-amino-4-methylcoumarin as the major product. The difference in the intersystem crossing rate between the two compounds originates from the azido position relative to the carbonyl group. Because of its ability to form a covalent linkage with a nucleophile, 6-azidocoumarin is deemed to have a greater potential as a photoaffinity label than 7-azido-4-methylcoumarin.     

PHOTOCHEMICAL REACTIONS OF DIBROMOTHYMOQUINONE

Abstract The photosynthetic electron transport inhibitor dibromothymoquinone was found to mediate the photoreduction of horse heart cytochrome c in aqueous solution. This process appears to involve the reduction of dibromothymoquinone to the corresponding hydroquinone followed by direct electron transfer to cytochrome c. A subsequent'autoxidation'of the reduced cytochrome c takes place which requires the presence of both oxygen and quinone. Irradiation of ethanolic stock solutions of dibromothymoquinone generates a hydroquinone species which is (1) capable of reducing cytochrome c directly in aqueous solution in the dark and (2) chemically distinct from the parent compound. This photore-duced species is stabilized in ethanolic solution but undergoes autoxidation ( t _1/2= 24 s) when placed in an aqueous medium. Because dibromothymoquinone is used in photosynthetic studies, some care must be taken to avoid complications which might arise from the above reactions; suitable precautions are discussed.     

A THEORETICAL STUDY OF MECHANISMS IN THE PHOTOCHEMICAL REACTIONS OF FORMING XETENE AFTER THE α-EOND RUPTURE IN CYCLCHEMANONE

ab initio,SCF+CI calculations of the potential energy surfaces and barries in the various paths are presented for the chemical reactions of forming ketene after the a-bond rupture in cyclohexanone,using acetaldehyde as model.The possibilities of the various paths and thansition states of the important paths are discussed.