反相微乳液法制备纳米Ag2S增感剂的化学增感研究

本文用反相微乳液法制备了纳米Ag₂S,并用作卤化银乳剂的硫增感剂,研究了其增感效果、增感规律及可能的增感机理.反相微乳液由异辛烷、表面活性剂AOT钠盐和水形成;制得的Ag₂S粒径3—5 nm;用制得颗粒增感卤化银乳剂,获得的感光性能优越于用Na₂S₂O₃水溶液增感;增感规律的研究表明,随着乳剂中纳米Ag₂S浓度的增加,模型乳剂感光度迅速提高、灰雾变化不大,并在100—200μmol/molAg左右获得最佳感光性能,进一步增加浓度则感光度呈下降趋势、灰雾升高;获得最佳感光性能所需的化学增感时间很短,约40分钟,之后感光度不再增加、灰雾上升;用漫反射光谱(DRS)作探针,跟踪记录增感时卤化银微晶表面上纳米Ag₂S增感剂颗粒的演变,为新型纳米增感剂的优异增感特性提供了机理性解释.     

新型卤化银微晶——中空颗粒乳剂的制备

近十五年来,卤化银感光乳剂的制备有了长足的发展,出现了一系列新型卤化银微晶,例如扁平T-颗粒、双层结构颗粒、外延复合晶体、多层结构颗粒、糙面颗粒等等.这些新型微晶乳剂的出现使“微粒高感”成为可能,在此基础上开发出的新一代彩色和黑白感光材料的质量和性能达到了前所未有的高水平.这表明卤化银乳剂制备技术的更新对感光材料的发展起着决定性的作用.     

新型中空卤化银颗粒乳剂的制备和性能研究 Ⅲ.中空卤化银颗粒乳剂感光性能的研究

本文应用表面显影、Dember效应、化学成熟、光谱增感等方法,对照实心立方体溴化银乳剂研究了中空卤化银微晶的结构与光物理性质及感光性能的关系。实验结果表明:(1)中空卤化银的潜影在孔洞处优先形成;(2)中空卤化银微晶中位错、缺陷较多,其填隙银离子浓度较大,电子陷阱较多;(3)中空颗粒表面反应活性高,感光度高,光谱增感效果好;(4)中空颗粒乳剂其反差较大,最大密度较高;(5)上述结果均可归因于中空卤化银微晶所特有的孔洞结构。     

金属离子对溴碘化银乳剂微晶体的掺杂效应——Ⅰ.Fe3+的掺杂

应用常规感光测定法、电镜法、介电损耗仪和微波光导仪研究了Fe³⁺对卤化根乳剂微晶的掺杂效应,结果表明:Fe³⁺使卤化银乳剂的感光度降低,灰雾降低,而反差变化不大。电镜观察和介电损耗测量表明:Fe³⁺在物理成熟过程中对乳剂颗粒大小和离子电导率的影响不大,而微波光导数据表明,掺杂对电子电导的影响是明显的。上述结果表明:在AgBr中,Fe³⁺起了深的电子陷阱作用,使光电子徙动路程缩短,影响潜影的形成效率。     

N,N′-二(芳磺酰)亚磺酰胺-S-(2-苯并咪唑)钠作为稳定剂的研究

研究了新型感光稳定剂Ｎ，Ｎ′－二（芳磺酰）亚磺酰胺－Ｓ－（２－苯并咪唑）钠（芳磺酰基为苯磺酰，对甲苯磺酰，对氯苯磺酰）与增感染料在实用照相乳剂中的超增感与防灰雾作用。实验结果表明，在多种不同组分的卤化银乳剂中，可提高感光度，抑制灰雾或对感光度和灰雾具有一致的理想效果。     

氯化银立方体微晶乳剂和{100}面扁平微晶乳剂的甲酸盐掺杂增感

将甲酸盐掺杂在乳剂微晶不同位置处,制备成氯化银立方体微晶乳剂和{100}面扁平微晶乳剂.实验发现:作为正空穴捕获剂,适当计量的甲酸盐在不增加乳剂灰雾的前提下,可使上述乳剂的感光度提升3—8倍.甲酸盐在两种晶形乳剂的不同位置掺杂的研究结果显示,甲酸盐均匀掺杂可比表面掺杂获得更高的感光度.在两种乳剂中甲酸盐掺杂增感都可与其后的硫增感、硫加金增感以及光谱增感协同作用,进一步提升乳剂的感光性能.     

卤化银微晶中掺杂的Ca离子对其性能的影响

本文研究了在卤化银微晶沉淀过程中不同量的Ca离子掺杂对其离子电导和照相性能的影响。掺杂Ca离子使卤化银乳剂的介电损耗曲线上的吸收峰向低频方向移动。相应卤化银乳剂的感光度也有一定程度的提高。     

碘在卤化银微晶的成核及生长过程中的作用

现代卤化银高感照相乳剂大多是具有不同碘含量和碘分布的溴碘化银乳剂.由于碘化银参与到晶体成核和生长的不同阶段,便出现了所谓双层结构、多层结构、核壳结构等不同类型的实用卤化银照相乳剂.因此,对于碘在卤化银结晶过程中的作用的认识就显得尤为重要.本文通过文献综述旨在探讨碘对卤化银晶体成核与生长的影响.     

纳米尺寸ZnS化学增感剂

本文发现硫化锌纳米粒子对卤化银乳剂的化学增感作用 .采用水不溶性的硫化锌纳米粒子作为化学增感剂 ,与水溶性的硫代硫酸钠增感剂相比 ,可以在不增加乳剂灰雾的条件下明显提高卤化银乳剂的感光度及反差     

冠醚对溴化银乳剂的增感作用

近年来,已有将冠醚化合物用于卤化银感光乳剂中的一些报道^[1-4]。为了改善卤化银感光材料的性能,我们将合成的一种新冠醚——N-对甲苯磺酰基-7-氮杂-1,4,10,13-四硫杂环十六烷(NTsTTH)用于卤化银乳剂中,发现它能提高卤化银乳剂的感光度。     

Investigations on the preparation,oxidation and reduction reactions of thiophosphoryl fluoride

Pure thiophosphoryl fluoride has been prepared by the fluorination of thiophosphoryl chloride by sodium fluoride in acetonitrile medium. Oxidation of this phosphoryl fluoride by acidified chloramine-T ruptures the phosphorus-sulphur bond and oxidises the sulphur present to the hexavalent state. Anhydrous hydrogen iodide reduces the sulphur to hydrogen sulphide and phosphorus to the trivalent state.     

Dual graphs realized in the compounds di-μ3-4-mercaptopyridine catena-di-μ2-iodo-di-μ3-iodo-μ4-iodo penta copper(I) and di-μ3-4-mercaptopyridine-di-catena-iodo-di-μ3-iodo tri copper(I)

Two compounds, [Cu5I5](SNC5H4)2 [i] and [Cu3I3](SNC5H4)2 [ii], were synthesized under hydrothermal conditions and the crystal structures were solved. Both compounds crystallized in space group I41/a. The iodide and the sulphur from mercaptopyridine are connected to copper atom, giving the copper atoms tetrahedral coordination geometry. The pyridine end of the organic moiety is non-bonding and fills the empty space around the tetrahedra formed from copper, sulphur and iodide.     

Coupling vs surface-etching reactions of alkyl halides on GaAs(100). 2. CH2I2 reactions

Surface reactions of CH2I2 on gallium-rich GaAs(100)-(4 x 1), studied by temperature programmed desorption and X-ray photoelectron spectroscopy (XPS), show CH2I2 adsorbs dissociatively at liquid nitrogen temperatures to form surface chemisorbed CH2(ads) and I(ads) species. Controlled hydrogenation of a fraction of the CH2(ads) species in the chemisorbed layer by the background hydrogen radicals results in a surface layer comprising both CH3(ads) and CH2(ads) species. This hydrogenation step initiates a plethora of further surface reactions involving these two species and I(ads). Thermal activation leads to three sequential methylene insertions (CH2(ads)) into the CH3-surface bond to form three higher alkyl (ethyl (C2), propyl (C3), and butyl (C4)) species, which undergo beta-hydride elimination to evolve the respective higher alkene (ethene, propene, and butene). In competition with beta-hydride elimination, reductive elimination of the ethyl and propyl species with I(ads) occurs to liberate the respective alkyl iodide. Beta-hydride elimination in the alkyls, in the temperature range 420-520 K, is the more dominant pathway, and it is also the rate-limiting step for further chain propagation. The evolution of the alkyl iodides represents the only pathway for the removal of surface iodines in this study and is different from previous investigations where gallium and arsenic iodide etch products (GaI(x), AsI(x) (x = 1-3)) formed instead. The desorption of methane and methyl iodide, formed from surface CH3(ads) species at high temperatures by the reaction between surface methylenes and hydrogens eliminated from the surface C2-C4 alkyls, terminates the chain propagation. We discuss the reaction mechanisms by which the observed reaction products form and postulate reasons for the reaction pathways adopted by the surface species.     

Photometric titration of total iodine at trace levels in concetrated chloride solutions

The method is based on reduction of total iodine (10^?7?10^?5 M), to iodide with sulphite in acidic solution. The excess of sulphur dioxide is removed by bubbling with nitrogen, and the resulting solution is titrated spectrophotometrically with a standard solution of iodate, the absorbance being measured at 230 nm. Some Italian table salts, iodized or common, were analyzed for their iodide and total iodine content.     

Analytical applications of condensed phosphoric acid-III Iodometric determination of sulphur after reduction of sulphate with sodium hypophosphite and either tin metal or potassium iodide in condensed phosphoric acid

Novel methods for the reduction of sulphate to hydrogen sulphide with hypophosphite-tin metal or hypophosphite-iodide in condensed phosphoric acid (CPA) are proposed. The reduction of sulphate with hypophosphite alone does not proceed quantitatively. Sulphate, however, is quantitatively decomposed with hypophosphite when tin metal or potassium iodide is used together with it. The determination of sulphur by the hypophosphite-tin metal-CPA and tin(II)-CPA methods is interfered with by copper on account of the stabilization of copper(I) sulphide, but this interference can be eliminated by adding iodide, e.g. potassium and lead salts. Alum and barytes are quantitatively decomposed within 15 min at 140 and 280 degrees , respectively. The hydrogen sulphide evolved is absorbed in zinc acetate solution at pH 4.5 and then determined by iodometry.     

10-十一烯酸衍生物混合体系的表面化学

自表面张力测定对１０－十一烯酸胆碱衍生物（三甲基－［２－（１０－十一烯酰氧乙基）］碘化铵）与１０－十一烯酸钠混合体系的表面吸附和胶团形成作了研究；对该体系中的囊泡形成进行了电镜观察。结果表明，疏水链端基为不饱和烯基的正、负离子表面活性剂混合体系和有饱和疏水链的混合体系一样，也有很高的表面活性，易于表面吸附和形成胶团，并且容易在水及乙醇－水溶液中形成相当稳定的囊泡。这些结果的原因可归之于正、负表面活     

Carbon molecular sieves produced by the fixation of sulphur surface complexes

Summary A Saran carbon has been treated with carbon disulphide and sulphur in order to introduce sulphur surface complexes, a commercial activated carbon was also used. Samples obtained were characterized by their surface areas and porosities. The adsorption of n-hexane, benzene and cyclohexane has been measured out at high temperatures and under dynamic conditions using a gas chromatographic technique. Results were compared with those obtained when oxygen-surface complexes were introduced and it can be concluded that when CS₂ is used with a highly microporous carbon, such as Saran, a molecular sieve for cyclohexane (mean size 0.58 nm) is produced at determined amounts of sulphur fixed.     

Iodide adsorption on the surface of chemically pretreated clinoptilolite

The possibility to use the monoionic Ag⁺-form (eventually Hg⁺- and Hg²⁺- forms) of clinoptilolite of domestic origin for radioactive iodide elimination from waters has been studied. The capacity of the monoforms of clinoptilolite towards iodide exceeds many times that of the capacity of clinoptilolite in natural form. Due to the low solubility product of AgI, Hg₂I₂ and HgI₂ iodides generate precipitates on the zeolite surface. Rtg analyses of the silver form of clinoptilolite after sorption of iodide demonstrate the formation of new crystals on the zeolite surface. The influence of interfering anions on the adsorption capacity of silver clinoptilolite towards iodide was investigated, too. Kinetic curves of iodide desorption from the surface of silver and mercury clinoptilolite were compared. Simultaneously, adsorption isotherms for the systems aqueous iodide solution/Ag^–, Hg-clinoptilolite were determined.     

X-ray diffraction and STM study of reactive surfaces under electrochemical control: Cl and I on Cu(100)

The surface structure of Cu(100) modified by chloride and iodide has been studied in an electrochemical environment by means of in-situ scanning tunneling microscopy in combination with in-situ surface X-ray diffraction with a particular focus on adsorbate and potential dependent surface relaxation phenomena. For positive potentials close to the on-set of the copper dissolution reaction, the X-ray data disclose an extraordinarily large Cu-Cl bond length of 2.61 A for the c(2 x 2)-Cl phase. This finding points to a largely ionic character of the Cu-Cl interaction at the Cu(100) surface, with chloride particles likely to retain their full charge upon adsorption. Together with the positive surface charging at these high potentials, this ionic Cu-Cl bond drives the observed 2.2% outward relaxation between the first two copper layers. These results indicate that the bond between the first and the second copper layer is significantly weakened which appears as the crucial prerequisite for the high surface mobility of copper-chloride species under electrochemical annealing conditions at these high potentials. With 2.51 A the Cu-I bond is 4% shorter than the Cu-Cl bond implying that the nature of the Cu-I bond is mainly covalent. Accordingly, we observe a significant inward relaxation of the top Cu layers upon substituting chloride by iodide at the same electrode potential, which suggests that the iodide adsorption involves charge transfer from the halide to the copper substrate.     

用俄歇能谱和X射线能谱研究板状碘溴化银微晶中的碘离子的空间分布

本文制备了一系列不同碘含量的板状碘溴化银微晶(微晶大小约为3微米)。运用扫描透射电镜和X射线能谱仪(EDS)对单个微晶进行了分析和研究,半定量地测定了碘离子在板状微晶中的面分布;运用扫描俄歇微区棵针(SAM)和二次电子像、离子溅射剥层技术对微晶进行了表面及其纵深的碘离子的点分析,根据EDS和SAM的结果,可以得到板状碘溴化银微晶中的碘离子的空间分布。实验结果表明在板状缺溴化银微晶中,在其中心部位的碘含量最高;越靠近横向边缘的位置,碘含量越低。且在制备碘溴化银微晶时,如果pAg值较高,将会使在制备早期加入的碘离子通过不断的重结晶向微晶表面扩散,得到的微晶不是夹心结构的碘溴化银微晶。