IMAGING SCIENCE AND PHOTOCHEMISTRY

STUDIES ON THE MORPHOLOGY OF DYE IMAGES——THE FORMATION OF DYE CLOUDS AND THE CHANGE IN MORPHOLOGY IN THE COURSE OF CHROMOGENIC DEVELOPMENT

ZHAO XIN, KONG GUI-ZHI, REN XIN-MIN(JEN HSIN-MIN)

1984, 2(4): 1-6. DOI: 10.7517/j.issn.1674-0475.1984.04.1

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The morphology of dye clouds formed on large silver bromide crystal (30-40 μm) in the course of chromogenic development, was observed and photographed through microscope. The influence of competing and DIR couplers on the morphology of the dye clouds was also studied. Highly-dispersed hydrophobie cyan couplers and CD-3 were used in the experiments.

STUDIES ON THE ADJACENCY EFFECT IN PHOTOGRAPHIC DEVELOPMENT

LIU QUAN, LIU CHUN-YAN, REN XIN-MIN(JEN HSIN-MIN)

1984, 2(4): 7-12. DOI: 10.7517/j.issn.1674-0475.1984.04.7

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The adjacency effect in photographic development was studied. The p-phenylene-diamine type developers were used in both black-and-white and color development for the convenience of comparison. In black-and-white development a linear relationship was found to hold between the density increment on the boarder side (δ) and the large-area density difference (H) for a given film-developer combination:δ = αH + b a can be used as a measure of the magnitude of the adjacency effect. The influences of developer activity, concentration of developing agent, developing time and pH of the developer on the adjacency effect were also studied. In color development a complicated relationship between the adjacency effects of silver and dye images was observed.

THE ISOELECTRIC POINT DISTRIBUTION OF MODIFIED GELATINS

CHEN LI-JUAN, PENG BI-XIAN

1984, 2(4): 13-19. DOI: 10.7517/j.issn.1674-0475.1984.04.13

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Modified gelatin is widely used as coagulating agent in photographic emulsion-making, but the coagulation mechanism is still obscure. The isoelectric point distribution is one of the most important factors affecting the coagulating property of modified gelatin. In the present work the new technique of isoelectric focusing with some modifications is used in the determination of the isoelectric points of parent and modified gelatins. The experimental data can be used to account for the reason why modified gelatin and the photographic emulsion prepared with it can be coagulated only within a definite range of pH.

CORRELATION OF SPECTRAL SENSITIZATION OF CYANINE DYES TO THEIR STRUCTURE FROM THE VIEWPOINT OF REDOX POTENTIAL

SHEN TAO

1984, 2(4): 20-27. DOI: 10.7517/j.issn.1674-0475.1984.04.20

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The redox potential of some cyanine dyes in CH₃OH and CH₃CN was measured using cyclic voltammetry. The unmeasured one was evaluated from the excitation energy by means of the linear correlation analysis. They were compared with the data compiled ’from literature under the same conditions. The effect of many structural factors of cyanine dyes on their redox potential, so on their spectral sensitization was reviewed in detail. A practical approach was suggested to choose excellent sensitizers from the viewpoint of redox potential.

A STUDY ON THE FLUORESCENCE SPECTRA OF A NOVEL MONOMER——DIMETHYL AMINOPHENYL ACRYLAMIDE (DMAPAA) AND ITS POLYMER SOLUTION

WU SHI-KANG, ZHU QING-QING, LI FU-MIAN, FENG XIN-DE

1984, 2(4): 28-33. DOI: 10.7517/j.issn.1674-0475.1984.04.28

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The fluorescence spectra of a novel monomer, dimethyl aminophenyl acrylamide solution, and its polymer solution have been studied in this work. Results have shown that, there are two parts, electron donor and acceptor, in a single molecule. The electron transfer between molecules was occured by light excitation. The fluorescence intensity of this monomer is weaker, than that of its corresponding polymer. This monomer could be polymerized by light excitation.

PHOTOCHEMISTRY OF 1,1-DIMETHYL-2-ARYLCYCLOPROPANE

WU GUO-SHBNG, JIANG LONG-XIANG

1984, 2(4): 34-40. DOI: 10.7517/j.issn.1674-0475.1984.04.34

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A successful use of lithium dicyclohexylamine as a base in practical syntheses of 1,1-dimethyl-2-(1-naphthyl) cyclopropane (1) and 1,1-dimethyl-2-(9-phenanthryl) cyclopropane (2) from the corresponding ArCH,Cl and isobuterie was reported. Direct irradiation of (1) or (2) led to the corresponding 2-methyl-4-aryl-1-butene (major product), arylethylene and 2,3-dimethyl-2-butene. Euns with benzhydrol and benzopheno-ne present showed that both (1) and (2) quenched benzopinacolization and therefore demonstrated that triplet transfer to (1) or (2) was indeed occuring. Hence the reaction is singlet process. The lacking of vertical excited state stabilization due to aryl group revealed that the p orbitals of aryl ring did not participate the reaction transion. Thus, the rearrangement is likely to proceed via a Hiickel-like four electron cyclic array transion, which followed the “small K vs large K” generalization.

INFLUENCE OF SPECIFIC ADSORPTION OF SURFACTANTS ON ENHANCED PHOTOVOLTAIC EFFECT ON THE PHOTOELECTRODE OF PHOTOSENSITIVE MOLECULAR SOLID FILM

LI YU-SHU, WEI MEI-DE, LIU ZHENG-HUI

1984, 2(4): 41-45. DOI: 10.7517/j.issn.1674-0475.1984.04.41

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The porphyrins as photoelectrodes in the photovoltaic cells of liquid junction type have been studied.In this paper, the adsorption isotherm of anion-surfactants at the solid surface, has been used to analyze the correlation between the ion concentration logarithmic function and the increase of photovoltaic effect. The influence of alkyl chain length, polar head group, cationic surfactants and non-ionic surfactants on the enhanced photovoltaic effect has also been studied. It has been shown that the effect of the structure of inner Helmholtz layer and the change of parameters on the photovotaic effect plays an important role in the photovoltaic cell.

PHOTOPOLYMERIZATION OF MMA INITIATED BY DISULFIDES

LI MIAO-ZHEN, CHANG ZHI-YING, ZHANG YAO-KUN, WANG ER-JIAN, FENG XIN-DE

1984, 2(4): 46-53. DOI: 10.7517/j.issn.1674-0475.1984.04.46

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Photopolymerization of methyl methacrylate (MMA) has been studied kinetically using several organic disulfides as photoinitiator. Experimental results show that the structural effect of disul’fides on polymerization rate Rp is quite obvious. The initiation activities of various disulfides may be arranged in following order (P-CH₃C₆S)₂ > (t-C₄H₉S)₂>(C₆H₅CH₂S)₂, (n-C₁₂H₂₅S)₂ and ((C₂H₅)₂NC₂H₄S)₂. The initiation efficiency of di-toluene disulfide (DMDS)can bear comparison with benzoin ethers. The RP was found to depend highly on the nature of solvents and is proportional to [MMA] and [DMDS]^0.1(N₂) or [DMDS]^0.2(O₂). The singlet and triplet energy of DMDS have been determined to be E_s72.2kcal/mol and E_T57.3kcal/mol, respectively, which considerably lower than that of conventional vinyl monomers.It indicates that DMDS is qualified as photoinitiator for vinyl polymerization. From the results obtained the initiation mechanism of polymerization is proposed and discussed.

PHOTOGRAFTING AND DYEING OF POLYPROPYLENE PLATE

GAO ZHI-MIN, YANG YONQ-YUAN, FENG SHU-JING, WU SHI-KANG

1984, 2(4): 54-58. DOI: 10.7517/j.issn.1674-0475.1984.04.54

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Various kinds of hydrophilic monomers (such as methacrylic acid and acrylamide) were grafted in the vapor phase onto polypropylene plate (1mm thickness) by photo-grafting in the presence of benzophenone as a photosensitizer. The hydrophobic surface of polypropylene plate was modified to a hydrophilic one by photografting. ESCA and the water contact angle measurements confirmed that the graft polymerization occu-red on the plate surface. Certain water-soluble dyes (crystal violet and rhodamine B) showed a strong affinity for the grafted surface.

1984, 2(4): 59-59. DOI: 10.7517/j.issn.1674-0475.1984.04.59

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