照相明胶层中金催化的无电沉积的正电子湮没研究

采用正电子湮没技术（ＰＡＴ）研究了照相明胶中的自由体积空穴在无电沉积过程中的作用机理。研究结果表明,洁化饱和后,照相明胶的自由体积空;穴的平均尺寸约减小０．０１１ｎｍ＾２,相当于一个Ａｕ原子的体积的大小,即照相明胶大分子中的每个自由体积穸穴平均填充了一个Ａｕ原子,该ＡＵ原子作为催化活性核催化铜的沉积,使物理显影生成的影像为紧密铜粒子的堆积形貌,而不是丝状形貌,铜经无电沉积饱和后,照相明胶的自由体积     

明胶/卤化银乳剂体系正电子湮没研究

长期以来,显影过程特别是银丝的生成机理一直是感光工作者关注和研究的焦点.但迄今为止,众说纷坛的各种假说尚未达到共识,本文用正电子湮没技术(PAT)测定了乳剂的正电子湮没寿命谱,探讨了银丝在自由体积空穴中的生长机理,并采用透射电子显微镜观察除去明胶后的银丝形貌,验证了PAT实验中银丝生长的结论.同时本文根据明胶中蛋氨酸及其氧化产物的大致含量,首次采用正电子湮没技术(PAT)研究将蛋氨酸及其氧化产物加到照相乳剂中,观察蛋氨酸及其氧化产物的还原性以及在水洗前加入蛋氨酸和在水洗后加入蛋氨酸的差别.得到了如下实验结果.     

AgBrI超细颗粒乳剂的电性能和感光性能

７０年代,人们对纳米粒子的“量子尺寸效应”和它的介观相特性进行了初步的研究．近２０年来,这一领域得到了迅速的发展．它们的发展在很大程度上推动了照相化学的发展,对揭示照相过程中潜影银簇、显影银丝等和超细粒子有关的特殊现象的本质及机理有着不可低估的作用．...     

明胶与Ag+相互作用的XPS研究

X射线光电子能谱(XPS)技术是一种高灵敏、高分辨的元素定性定量和结构分析技术.本文用该技术研究了照相明胶中S原子与Ag+相互作用的本质.研究结果表明,照相明胶中的蛋氨酸、蛋氨酸亚砜残基均能通过S原子与Ag+作用,而且在所研究的明胶中蛋氨酸亚砜残基的含量远高于蛋氨酸残基的含量,这意味着在与Ag+键合过程中前者占有更重要的地位.此外,本文还比较了不同原料制成的明胶与Ag+的作用情况.     

纳米科技的发展对卤化银技术进步的影响

纳米科技和纳米材料在过去的十几年得到了迅速的发展 ,并将继续发展并渗透到各个领域 ,给世界和人类生活带来不可估量的影响 .“纳米技术”真的是一个新的概念 ?事实上 ,某些材料的制备和使用早已经涉及了这个长度范围 .卤化银照相技术就是“老”的纳米技术之一 .在早期 ,从事卤化银照相的人们凭经验和有限的能力控制材料的某些结构在纳米级范畴 .随着纳米科学的发展 ,纳米技术在卤化银照相领域的使用走过了从无意识到有目的的过程 ,促进了照相科学的发展 .本论文将结合卤化银技术在 2 1世纪的发展趋势 ,从三个方面 (在纳米级研究卤化银照相、卤化银微晶上的纳米结构、纳米卤化银微粒 )探讨纳米科学对卤化银技术进步的影响     

Ag+在照相明胶不同分子量组分中的分布

利用凝胶排阻层析-火焰原子吸收光谱法研究了Ag+在照相明胶中分子量的分布情况.研究表明,利用葡聚糖凝胶G-75可有效的将明胶中的γ、β、α及小分子蛋白L组分分开.发现Ag+完全分布于分子量较小的α大分子蛋白组分.γ组分、β组分中均不存在Ag+.     

酞嗪在苯并三氮唑银光敏热显影体系中的调色机理研究

本文对调色剂酞嗪(PHZ)在苯并三氮唑银(AgBTA)光敏热显影体系中的作用机理进行了初步研究.通过SEM,IR,XRD分析结果表明,PHZ与AgB-TA生成银复合物从而发挥显影促进作用.该复合物可以改变AgBTA颗粒的形状.生成的银复合物具有与AgBTA相同的晶体结构.     

照相明胶与化学增感剂相互作用的XPS研究

本文采用Ｘ射线光电子能谱技术研究了两种照相明胶与化学增感剂相互作用的机理．当两种照相明胶样品在ＨＡｕＣｌ４溶液中反应５ｍｉｎ后，明胶中的蛋氨酸、蛋氨酸亚砜均被氧化为蛋氨酸砜．与此同时，明胶吸附的大部分Ａｕ３＋被还原为Ａｕ＋，并且Ａｕ＋以络合形态存在于明胶之中．根据与ＡｕＣｌ３反应之后明胶中Ａｕ３＋与Ａｕ＋的比例，法国明胶的还原性略高于包头明胶．添加到明胶中的Ｎａ２Ｓ２Ｏ３能将明胶大分子所含的蛋氨酸亚砜全部还原为蛋氨酸．Ｓ２Ｏ３２－、蛋氨酸和蛋氨酸砜可以稳定共存于明胶体系之中，外加的Ｓ２Ｏ３２－的还原性高于明胶中蛋氨酸、蛋氨酸亚砜的还原性．添加Ｎａ２Ｓ２Ｏ３后的两种照相明胶均可以将其溶胀吸附的Ａｕ３＋全部还原为胶态金．此时，参与氧化还原反应的主要基团是Ｓ２Ｏ３２－而非明胶中的蛋氨酸残基．由于Ｎａ２Ｓ２Ｏ３的添加，照相明胶对ＡｕＣｌ３的还原能力增强     

卤化银颗粒潜影形成过程中的空穴转换和利用

长期以来,在研究提高卤化银乳剂潜影形成效率的化学增感技术时,都侧重于对光生电子的行为和过程研究,而对孪生的正空穴的走向关注甚少.这种思路近年来有所改变,逐渐从如何把电子与空穴有效分离转变为如何对空穴的有效利用上,即把空穴通过化学方法转换成电子或电子载体以达到提高潜影形成效率的目的.本论文工作是以甲酸盐作为空穴捕获剂,研究它在卤化银颗粒中的掺杂技术并考察这种掺杂乳剂的增感作用.     

一种新型功能性显影促进剂的照相性能和抗老化性研究

研究了新型功能性显影促进剂照相性能与作用机理.照相性能试验结果表明:显影促进剂M能明显提高感光度而且具有良好的抗老化性能;染料吸收光谱的结果表明:它的使用不影响主成色剂成色染料的吸收光谱.     

Room temperature synthesis of silver nanowires from tabular silver bromide crystals in the presence of gelatin

Long silver nanowires were synthesized at room temperature by a simple and fast process derived from the development of photographic films. A film consisting of an emulsion of tabular silver bromide grains in gelatin was treated with a photographic developer (4-(methylamino)phenol sulfate (metol), citric acid) in the presence of additional aqueous silver nitrate. The silver nanowires have lengths of more than 50 μm, some even more than 100 μm, and average diameters of about 80 nm. Approximately, 70% of the metallic silver formed in the reduction consists of silver nanowires. Selected area electron diffraction (SAED) results indicate that the silver nanowires grow along the [111] direction. It was found that the presence of gelatin, tabular silver bromide crystals and silver ions in solution are essential for the formation of the silver nanowires. The nanowires appear to originate from the edges of the silver bromide crystals. They were characterized by transmission electron microscopy (TEM), SAED, scanning electron microscopy (SEM), and powder X-ray diffraction (XRD).     

A Unique Au–Ag–Au Triangular Motif in a Trimetallic Halonium Dication: Silver Incorporation in a Gold(I) Catalyst

As a result of explorations into the solution chemistry of silver/gold mixtures, a unique diphosphine trimetallic chloronium dication was discovered that incorporates silver–arene chelation and a triangular mixed gold/silver core in the solid state. Notably, it was isolated from a Celite prefiltered solution initially thought to be silver‐free. The crystal structure also incorporates the coordination to silver of one fluorine atom of one SbF₆^? counterion. The structure was compared to two new, but well‐precedented, phosphine digold chloride cations. DFT calculations supported significant silver–halide and silver–arene interactions in the mixed gold/silver complex and metallophilic interactions in all three complexes. Comparison of computed data revealed that the ωB97X‐D functional, which has a long‐range corrected hybrid with atom–atom dispersion corrections, gave a better fit to the experimental data compared with the PBE0 functional, which has previously failed to capture aurophilic interactions. Preliminary studies support the presence of the mixed gold/silver structure in solution.     

卤化银乳剂制备中的新型掺杂剂

本文综述了近年来乳剂制备中常用的新型掺杂剂 ,较详细地介绍了两种能提高光电子利用效率的掺杂剂 ,即过渡金属络合物浅电子陷阱掺杂剂和羧酸盐(酯 )有机空穴陷阱掺杂剂 ,总结了掺杂剂的选择原则 ,并举例说明了掺杂剂对乳剂感光度的影响 .     

Free volume holes diffusion to describe physical aging in poly(mehtyl methacrylate)/silica nanocomposites

The spontaneous thermodynamically driven densification, the so-called physical aging, of glassy poly(mehtyl methacrylate) (PMMA) and its nanocomposites with silica has been described by means of the free volume holes diffusion model. This mechanism is able to account for the partial decoupling between physical aging and segmental dynamics of PMMA in nancomposites. The former has been found to be accelerated in PMMA/silica nanocomposites in comparison to "bulk" PMMA, whereas no difference between the segmental dynamics of bulk PMMA and that of the same polymer in nanocomposites has been observed. Thus, the rate of physical aging also depends on the amount of interface polymer/nanoparticles, where free volume holes disappear after diffusing through the polymer matrix. The free volume holes diffusion model is able to nicely capture the phenomenology of the physical aging process with a structure dependent diffusion coefficient.     

A new instrument for measuring the viscoelastic properties of dilute polymer solutions

A new oscillating capillary viscometer has been developed and used for measuring viscoelastic flow properties of dilute polymer solutions. These flow properties are determined from measurements of the pressure to volume flow relationships for sinusoidal flow in cylindrical glass capillaries. The theory for this measurement procedure is based upon the known theory for oscillatory flow of a viscoelastic fluid in circular tubes and which is presented with a few supplementations in this paper.The oscillatory flow is generated by a piezoelectric driver which is dipped directly into the aqueous solution. The advantage of this driver is that the excitation voltage for the piston is a direct measure of the motion of the piston. Changes in pressure are measured with a sensitive low-pressure quartz tranducer.The viscometer was tested with aqueous glycerol solutions and a gelatin gel. The viscoelastic flow properties of dilute polymer solutions (gelatin, gelatin/color-coupler, polyacrylamide) were then investigated in the frequency range 5 Hz to 150 Hz at very small volume flow amplitudes. The results presented illustrate the suitability of the method. The results are also evaluated with regard to the stabilizing action of slightly viscoelastic gelatinous coating liquids in the high-speed coating process in the manufacture of photographic materials.     

Development kinetics of silver clusters on silver halides

Silver nuclei are produced by pulse radiolysis at the surface of AgCl nanocrystallites in the presence of an electron donor, the methyl viologen, which induces the growth of silver nuclei. The experimental results observed on the increase of the silver atom concentration and on the decay of the donor concentration during this process, which is similar to the photographic development by an electron donor, are compared with the kinetics obtained from numerical simulation. The model assumes that the formation of silver clusters with a supercritical nuclearity is required before the start of an electron transfer reaction from the two reduced forms of the donor methyl viologen to the silver clusters. The reaction is controlled by the access of the donor to the surface sites of the AgCl crystallite. The rate constant values of the successive steps of the mechanism are derived from the adjustment of calculated kinetics to experimental signals under various conditions, using a single set of parameters which are fairly suitable under all conditions studied.     

卤化银感光材料的现状和未来以及学会的作用(英文)

接着以前的几篇文章,作者从光吸收、潜影形成效率、最小潜影中心的尺寸以及材料储存期的稳定性角度,分析了卤化银感光材料已达到的性能现状.潜影形成的效率取决于由吸收的光子产生的量子产率、敏化中心对电子的俘获和光电子与正空穴间的复合.可以肯定,感光材料的性能提高尚有很大的余地.依据上述的考察及其与静态数字照相的比较,可预测未来世界的卤化银感光材料生产的发展会趋缓.有一点应清楚,感光科学与技术彼此间已互动促进了许多年,生产出了高精细、高复杂的感光材料,此类科学与技术不是一些后来者能轻而易举超越的,而且它们所取得的各项进展无不依赖于感光科学和技术学会的种种活动.     

Rheology and stability of oil-in-water nanoemulsions stabilised by anionic surfactant and gelatin 2) addition of homologous series of sugar-based co-surfactants

The oil-in-water emulsions used in silver-halide photographic coatings are stabilised with anionic surfactants and made in the presence of excess gelatin, which acts as an electrosteric stabilising agent and continuous phase viscosifier. The oil droplet sizes are close to 100 nm but the adsorbed gelatin increases the effective volume of the droplets significantly. These nanoemulsions are manufactured and coated at temperatures in excess of 40 degrees C, where gelatin adopts a random coil structure. At oil concentrations above 15% by volume, the emulsions are viscoelastic liquids with a high low-shear viscosity and strong shear-thinning. The viscosity and shear-thinning can be decreased by reducing the adsorption of gelatin, which can be achieved by addition of nonionic surfactants. This is a rheological study of the effects of adding novel, nonionic sugar-based surfactants on the rheology of photographic nanoemulsions, with additional measurements of static and dynamic surface tension. These surfactants have two sugar (gluconamide) heads and either one or two alkyl tails. Homologous series of each type of sugar surfactant were investigated over a wide range of alkyl tail length. The optimum surfactant choice for commercial applications depends not only on rheological effects but also on ease of synthesis, purification and dissolution, and of course, cost. The dynamic surface tension of the emulsion containing the anionic-nonionic surfactant mixture must also be compatible with the multilayer coating process.