Table of Content

20 August 1983, Volume 1 Issue 3

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SOME IMPROVEMENTS IN MEASUREMENT OF MODULATION TRANSFER FUNCTION OF PHOTOGRAPHIC FILMS

HE GUANG-QIAN, ZHANG JING-XIAN, Liu GUI-TING

1983, 1(3):  1-5.  DOI: 10.7517/j.issn.1674-0475.1983.03.1

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In the determination of the MTP of photographic films by using a sinusoidal test object, errors may spring from granularity, data processing and sample alignment.In the present paper, measures such as accumulation in phase technique, computerized process control and a special technique of sample alignment are taken to minimize the experimental errors.The results are well reproducible and the time needed for scanning the whole test pattern is less than 3 minutes.

A STUDY ON THE DIELECTRIC SPECTRA OF DOPEDCUBIC SILVER BROMIDE EMULSIONSⅠ.EFFECT OF Cd⁺⁺ AND Cu⁺⁺ IONS

CHENG HU-MIN, Liu JUN

1983, 1(3):  6-15.  DOI: 10.7517/j.issn.1674-0475.1983.03.6

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The dielectric spectra of doped cubic silver bromide emulsions are studied.1-8 mol% Cd(NO₃)₂, CdCl₂, CdBr,, Cu(NO₃)₂, CuCl₂, CuBr₂, KCl and KBr are added into the cubic AgBr emulsions, respectively.It is observed that the peaks of dielectric loss curves are broadened and markedly shifted to lower frequencies in silver bromide emulsions with CdCl₂, and CdBr₂, while there is no change in dielectric spectra in the case of Cd(NFO₃)₂ and Cu(NO₃)₂ doping.For emulsion samples with CuCl₂, CuBr₂, KCl and KBr, the peaks of dielectric loss curves are shifted slightly to higher frequencies.On the basis of these experimental results, it is deduced that Cd⁺⁺ ions can incorporate into the crystal lattice on the surface of silver bromide crystal only in the presence of excess halogen ions in the emulsion, and that it is difficult for Cu⁺⁺ ions to incorporate into the crystal lattice even when excess halogen ions are present.The difference in the behaviour of Cd⁺⁺ and Cu⁺⁺ ions is attributed to the difference between the radii of both ions, the electron configuration of the ions and their coordination in the crystals.Finally, the condition under which the Sillars equation applies to a photographic emulsion system is considered.

THE PHOTOCYCLOADDITION BETWEEN 8-METHO-XYPSORALIN AND OLEFINESⅡ REACTIONS OF 8-MOP WITH CYCLOHEXENE AND 2,3-DIHYDRO-γ-PYRAN

AN JING-YI, ZHANG MAN-HUA, MA XI-HAN, JIANG LI-JINO

1983, 1(3):  16-20.  DOI: 10.7517/j.issn.1674-0475.1983.03.16

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The photocycloaddition between 8-methoxypsoralin (8-MOP) and cyclohexene has been studied previously.In this paper the photocycloaddition between 8-MOP and 2, 3-dihydro-y-pyran is further studied.The major products of both reactions are sepera-ted and identified, and their stereochemistry assigned.

PHOTOELECTROCHEMICAL STUDY OF n-TiO₂ ELECTRODE COVERED WITH TRACES OF NOBLE METALS

Wu YUE, DONG QING-HUA, ZHA QUAN-XING

1983, 1(3):  21-33.  DOI: 10.7517/j.issn.1674-0475.1983.03.21

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n-TiO₂ electrodes covered with traces of Pt and Ag were studied by measuring polarization curves both under illumination and in the dark in 1N NaOH solution flushed with O₂, or Ar.Experimental results showed that, in solution saturated with O₂, reduction of oxygen takes place on noble metal.The rate of the reaction is not affected by illumination of the electrode.In this case, photooxidation of water or other components takes place on the part of electrode surface which is not covered with noble metal.In other words, these two reactions act as a pair of conjugated reactions, just as a photoelectrochemical cell under short circuit.The rate of conjugated reactions is usually controlled by the rate of reduction of oxygen, which is favoured by the increase of the amount of noble methal on the surface of the semiconductor electrode.The current that flows through outer circuit is the algebraical sum of the partial currents of these two reactions.Eesults of interfacial impedance measurement and the analysis of polarization curves suggested that the type of contact between Pt or Ag and n-TiO₂ substrate is mainly ohmic.Therefore, the position of Fermi level of electron system in noble metal is the same as that in the bulk of semiconductor electrode.Photooxidation of CN^-and (C₂H₅)₂NH was carried out in solution containing TiO₂ powder covered with noble metals.The rate of photooxidation could be explained by the above suggested mechanism.

THE SOLVENT EFFECT ON THE FLUORESCENCE SPECTRAOF THE EXCIPLEX FORMED BY TEREPHTHALATECHROMOPHORES AND BENZENE

BAI FENG-LIAN, Wu PEI-JI, CHEN SHANG-XIAN

1983, 1(3):  34-40.  DOI: 10.7517/j.issn.1674-0475.1983.03.34

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The exciplex formation by terephthalate chromophores and benzene is reported.The solvent effect on the fluorescence spectra of the exciplex is examined and discussed.It is shown that the maximum of the exciplex fluorescence is dramatically affected by the acid strength of the solvent.In the aprotic solvent, the maximum of the exciplex fluorescence is located at a much lower frequency than in the protic solvent.The shift of the band maximum increases with increasing acid strength of the solvent.The relationship between the wavelength of the exciplex fluorescence band maximum and the characteristic parameter of the solvent obeys Brownstein equation satisfactorily.

THE INTERACTION BETWEEN DYES AND POLYMERSⅡ.THE RELATIONSHIP BETWEEN THE ABILITY FORPRODUCING SINGLET OXYGEN AND THE STATE OFAGGREGATION OF METHYLENE BLUE

Wu SHI-KANG, JIANG YONG-CAI, Liu RI-Xin, CHU QIN-QIN

1983, 1(3):  41-45.  DOI: 10.7517/j.issn.1674-0475.1983.03.41

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The interaction between polystyrene sulfonate and methylene blue was studied.In systems with different mole equivalent ratios (P/D) of polystyrene sulfonate to methylene blue, the latter was found to exist in different states of aggregation, which exerts a great influence on its ability for producing singlet oxygen.

1983, 1(3):  47-56.  DOI: 10.7517/j.issn.1674-0475.1983.03.47

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LIGHT PROTECTION BEHAVIOUR OF HINDERED AMINE LIGHT STABILIZER TINUVIN-770

PAN JIANG-QING, ZHANG CAN

1983, 1(3):  57-60.  DOI: 10.7517/j.issn.1674-0475.1983.03.57

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The light protection behaviour of hindered amine light stabilizer Tinuvin-770 is studied by IB, BSR, NMR as well as observation of a mechanical property of Tinuvin-770 containing polypropylene film.The results indicate that this light stabilizer shows an optimun concentration (0.3%, W/W) in photooxidation protection of polypropylene.With the concentration of Tinuvin-770 higher or lower than the optimum, the light protection property markedly deteriorates.This phenomenon may be related to the duality of sensitizing reaction and stabilization action of Tinuvin-770.The experimental results indicate that Tinuvin-770 is easy to photolyse under the experimental conditions reported.The free radicals produced by photolysis become the origin of photooxidation initiation.Careful ESR observation shows that the light stabilization action of Tinuvin-770 is due to the formation of the stable free radical 

CALCULATION OF THE CHARACTERISTIC PARAMETERSOF BLACK-AND-WHITE NEGATIVE PHOTOGRAPHICMATERIALS BY MATHEMATICAL SIMULATION

YIN SHI-FU

1983, 1(3):  61-65.  DOI: 10.7517/j.issn.1674-0475.1983.03.61

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In sensitometry, the sensitivity, contrast coefficient and fog density are generally deduced from characteristic curve graphically.The graphical method of determination of the characteristic parameters has certain limitations.In this paper, the author attempted to obtain these characteristic parameters by using mathematical models.

ANALYSIS OF THE YELLOW COLOR COUPLER Y-116 BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

SHI WEN-KUI

1983, 1(3):  66-72.  DOI: 10.7517/j.issn.1674-0475.1983.03.66

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A method of liquid chromatography for the determination of the yellow color coupler Y-116 is described.By using chemically bonded pellicular-nitrile as stationary phase and 5% tetrahydrofuran and 1% isopropanol in heptane as mobile phase, efficient separation of four components has been achieved.The Y-116 tautomers are characterized by the IE, NMR and MS spectroscopy and the by-products are identified.