IMAGING SCIENCE AND PHOTOCHEMISTRY

A STUDY ON THE DISSOLUTION OF GELATIN FROM CINE FILM

MIAO JIN-KANO, HUANG MING-ZHI

1984, 2(1): 1-6. DOI: 10.7517/j.issn.1674-0475.1984.01.1

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In this paper, the dissolution of gelatin from cine film into the processing solutions has been investigated by means of "gel" chromatography and UV spectrophotomethy, and the following results were obtained.1) It was proved that in the film and the processing solution there were extractable and extracted gelatins with molecular weight of 3000-30000.2) According to the solubility at room temperature, the commercial gelatins could be separated into two components "gel" (swelling component) and "sol" (soluble component). The results indicated that degradation of the "sol" goes faster than that of the "gel" due to its weaker ability of aggregation.3) The temperature and the degree of extraction are important factors effecting on the "sol" content in commercial gelatins. The product with minimum content of "sol" could be obtained by extracting gelatin at 50℃ after the extract at 45℃ had been removed. But the content of "sol" would increased with the extracting process in run by run.The experimental results showed that it is necessary to pretreat limed collagen before the extraction and control the degree of extraction, and the problem may thus be solved.

DETERMINATION OF MOLECULAR WEIGHT DISTRIBUTION OF GELATINS BY HIGH PERFORMANCE GEL PERMEATION CHROMATOGRAPHY

CHEN XIANG-FANG, PENG BI-XIAN

1984, 2(1): 7-14. DOI: 10.7517/j.issn.1674-0475.1984.01.7

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In present work the molecular weight distribution (MWD) of inert gelatins and modified gelatins was studied by High Performance Gel Permeation Chromatography. Three columns of μ-Bondagel E-linear was connected in series and used for separation. Sodium dodecyl sulfate (2%) was used as eluent. The α, β and γ components were used as standard samples. The M_N, M_W, M_Z and M_η of inert and modified gelatins were measured and compared with the calculated values. The degree of degradation of the parent gelatin during it’s modification process under high pH was determined and the results were discussed.

ROLE OF GOLD IN SULPHUR-PLUS-GOLD-SENSITIZED EMULSION——Ⅰ. GOLD AND PHOTOELECTRON TRAPPING

CHEN CI-PING, JIANG YONG-CAI, LIU DUN

1984, 2(1): 15-19. DOI: 10.7517/j.issn.1674-0475.1984.01.15

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The relation between gold in sulphur-plus-gold-sensitized pure silver bromide emulsion and photoelectron trapping in emulsion grains was investigated with a sulphur-sensitized emulsion as blank. Dember photovoltage and low-temperature luminescence spectrum measurements show that gold in sulphur-plus-gold-sensitized emulsion adds no contribution to photoelectron trapping during exposure.

EVOLUTION OF THE IMPURITY CENTRES IN PHOTOGRA- PHIC GRAINS AT DIFFERENT STAGES OF THE PHOTOGRAPHIC PROCESS AND ITS MECHANISTIC IMPLICATIONS Ⅱ.FORMATION OF THE TWO KINDS OF THE LARGEST IMPURITY CENTRES OF DIFFERENT SIZES

JI SU-XUE, LIU DUN

1984, 2(1): 20-25. DOI: 10.7517/j.issn.1674-0475.1984.01.20

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The formation of the two kinds of the largest impurity centres, of different sizes in emulsion grains was investigated by a method based on development kinetics on a pure silver bromide emulsion. The results show that under normal chemical sensitization and exposure conditions the smaller centres in the emulsion grains are formed primarily in the process of chemical ripening, whilst the major of the larger ones formed during exposure. The compatibility of the concept with some major kinetic features of chemical ripening and exposure was discussed.

CATALYTIC ACTION OF SURFACTANTS IN PHOTOPOLYMERIZATION CONTAINING OXYGEN

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

1984, 2(1): 26-31. DOI: 10.7517/j.issn.1674-0475.1984.01.26

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The catalytic action of some ionic surfactants of alkylammonium carboxylate type in the photopolymerization of MMA initiated by benaophenone/triethylamine/oxygen system has been studied. Experimental results show that the rate of polymerization depends upon the type, molecular structure and concentration of the surfactant. As a result of the accelerating effect of the surfactants on photosensitized decomposition of hydroperoxides formed in the system, the qiantum yield in the photopolymerization is increased by 2 times.

PHOTOINDUCED REDOX REACTIONS SENSITIZED BY METAL PHTHALOCYANINES—Ⅰ. ABSORPTION SPECTRA

XU HUI-JUN, ZHOU QING-FU, SHEN SHU-YIN

1984, 2(1): 32-39. DOI: 10.7517/j.issn.1674-0475.1984.01.32

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The absorption spectra of a series of metal phthalocyanine have been measured and their spectroscopic parameters calculated. They show similar monomer absorption spectra in the visible region with absorption maxima between 650-700 nm. The values of which show a little red shift with increasing solvent polarity. The central metal has little effect on the position of absorption maxima with decreasing order Mg ≥ Zn > Co. Some substituted phthalocyanines form dimers in less polar solvents, since they are non-photoactive, they can not be used as sensitizers. In this paper, the correlations of the formation of dimers with solvent polarity, concentration, nature of substituent group and central metal were investigated. The results show that the formation of dimers depends on the nature of substituent group, dielectric constant of solvent, and concentration. The monomer-dimer equilibrium constants K_eq = C_D/C_M of zinc sulfoamidophthalocyanines in chloroform and ethanol have also been calculated as 1 × 10^-6l. mol^-1.

PHOTOINDUGED REDOX REACTIONS SENSITIZED BY METAL PHTHALOCYANINES—Ⅱ. FLUORESCENCE SPECTRA CHARACTERISTICS AND PHOTOSEN- SITIZED REDUCTION OF VIOLOGEN

Xu HUI-JUN, ZHOU QING-FU, SHEN SHU-YIN

1984, 2(1): 40-48. DOI: 10.7517/j.issn.1674-0475.1984.01.40

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Some phthalocyanines have been synthesized and their fluorescence spectra studied. The fluorescence quantum yields have been measured, the value of which are 0.7, 0.3, 0.025 for magnesium, zinc and cobalt, respectively.Study of photosensitized reduction reaction together with the fluorescence quenching, the quenching rate constant k_q (1 × 10¹⁰ sec^-1) has been calculated. The result shows that the rate of the first step of photosensitized reduction, i.e. electron transfer reaction, is diffusion-controlled. Since EDTA can not quench the fluorescence of phthalocyanine, the following scheme for the reduction of RV²⁺ is proposed:

The photosensitization activities of phthalocyanines are in the order of Mg > Zn> Co, while the activity of butyl viologen is higher than that of methyl viologen.

THE PHOTOLUMINESCENCE AND ELECTROLUMINESCENCE OF INHOMOGENEOUS CADMIUM SULFO-SELENIDE ELECTRODES

TONG JIU-RU,A.B. ELLIS

1984, 2(1): 49-56. DOI: 10.7517/j.issn.1674-0475.1984.01.49

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When a n-type CdS single crystal is treated with Se vapor at 600-700℃, a layer of CdS_xSe_1-x (0<x<1) forms on the surface. The composition and the properties of photolu-minescence (PL) and electroluminescence (EL) of the samples depend on the Se vapor pre-sure, temperature and the time of the reaction. A red shift of emission bands were observed when X decreases. When the surface layer is thin enough, the EL spectra show the bands come from very near the surface (the diffusion layer) only and the PL spectra show the bands come both from the diffusion layer and the substrate. The fwhm of the emission bands of inhomogeneous samples (> 30 nm) is remarkably broader than that of homogeneous samples (single crystals). The Auger electron spectra connected with Ar ion sputter etching show that the thickness of the diffusion layer is about 0.2-2 μm under our experimental conditions.

EFFECT OF CONDITIONS OF SULFUR-GOLD SENSITIZATION ON PERFORMANCE OF PHOTOGRAPHIC EMULSION

LIU XING-QIN, FU YAN-XUN

1984, 2(1): 57-60. DOI: 10.7517/j.issn.1674-0475.1984.01.57

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A study of sulfur-gold sensitization on AgBr(I) emulsion used in the astrophoto-graphy was carried out, in which the effects of conditions of chemical sensitization such as the time interval between the addition of sulfur sensitizer and gold sensitizer and the ratio of sulfur to gold in weight on the photographic speed and low intensity reciprocity failure of the emulsion were experimentally investigated. The results showed that a significant improvement of the photographic performance of the emulsion could be obtained by choosing proper conditions of chemical sensitizatiou. In the present case the optimum time interval between the additions of the two sensitizers was 60 minutes and the optimum ratio of sulfur sensitizer to gold in weight was 3.5.

A STUDY ON THE PHOTOVOLTAIC PROPERTIES OF POLYTETRAPHENYL-PORPHYRIN

LIU YUN-QI, ZHU XIU-CHANG

1984, 2(1): 61-64. DOI: 10.7517/j.issn.1674-0475.1984.01.61

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In this report the photovoltaic properties of the poly-tetraphenyl-porphrin-platinum electrode were studied. In the solution of pH=1.5, the photovoltage is 0.555v, which increases with light intensity and decreases with the pH value.

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