两种不同银源的光敏热成像材料感光性能对比

本文考察了以苯并三氮唑银为银源与以硬脂酸银为银源的水基型PTG材料感光性能的差异,采用了原位法和异位法两种方法来制备不同的PTG材料,并采用了加热显影与湿法显影两种方法显影,结果显示以AgBTA为银源的PTG材料的感光度都比以AgSt为银源的PTG材料的感光度高.通过对乳液pH值和pAg值以及Dember光电压的测定,发现显影过程中以AgSt为银源的PTG材料显影程度要比以AgBTA为银源的PTG材料显影程度高,潜影形成过程中AgBTA体系的潜影形成效率比AgSt体系的潜影形成效率高,导致最终实验结果是以AgBTA为银源的PTG材料的感光度比以AgSt为银源的PTG材料的感光度高.     

混合银盐的光敏热成像材料感光性能研究

本文以原位法合成的AgBrI作为光敏剂,亲水型的聚乙烯醇为粘合剂,考察了以苯并三氮唑银和4-羟基-6甲基-1,3,3a,7-四氮茚银混合银盐为银源的光敏热成像材料的感光性能,实验结果表明:含AgTAI的混合银盐的PTG材料感光性能明显好于单纯AgBTA的PTG材料.通过光敏热成像材料乳液pH值pAg值测定及银盐DSC分析,认为混合银盐能够提高PTG材料感光性能的原因是其溶解度比AgBTA的溶解度大,能够提供充足的Ag⁺,增大显影密度,提高反差,且混合银盐颗粒尺寸小,其比表面积大,能够充分接触超细卤化银颗粒,从而促进热显影的进行.     

Silver-Phosphonate Based Metal Organic Frameworks: Synthesis and Antibacterial Action

Silver based Metal Organic Framework (MOF) materials were synthesized by the reaction of phospho-benzoic acid with silver salts under hydrothermal treatment and with/without urea. According to this procedure, either both functional groups (phosphonic acid and carboxylic acid) were engaged in iono-covalent bonds with silver atoms or, on the contrary, only the phosphonic acid function is engaged. Consequently, these materials exhibited different stability and their ability to release silver salts, when they were placed in water, was different. The antibacterial properties of these materials were attributed to the silver salt, released in solution.     

Silver Intercalation into Cellulose Matrix. An X-Ray Scattering,Solid-State 13C NMR,IR, X-Ray Photoelectron,and Raman Study

Diffusion of silver ions into a cellulose matrix and their subsequent reduction both with the matrix itself and with specific reducers lead to preparation of cellulose materials containing silver(0). Most silver metal is intercalated into the cellulose matrix when glycerol is used as solvent and potassium hypophosphite or sodium boron hydrate are used as reducers.     

Formation and biological activity of preparations based on microorganisms and colloidal silver

Results of studying the chemically induced synthesis of colloidal silver in microorganism cells are reported. It is suggested that three-dimensional structures that comprise colloidal silver crosslinked with matrix biopolymers are formed over the course of synthesis. Bactericide properties of synthesized biocomposite materials are studied before and after the lyophilization on Gramnegative bacteria and yeasts in both solid and liquid nutrients. Correlations between disperse characteristics of forming silver nanoparticles, surface properties, and the biological activity of preparations are demonstrated. Biocomposite preparations of ultradispersed silver synthesized by the reduction with sodium borohydrid are characterized by enhanced microbicide activity compared to analogous preparations synthesized with hydrazine.     

Nanoparticles and Nanotechnology in Silver Halide Imaging

Abstract

The future prospect of silver halide imaging materials was outlined and proceeded to the elucidation of the nanoparticles and nanotechnology, which would contribute to it. They include silver halide grains, J‐aggregates of sensitizing dyes, dispersions of dyes and couplers, silver nanoparticles and nanowires. A focus is placed on the combination of silver clusters and nanoparticles with silver halide grains, which makes greatest contribution to high performance of silver halide imaging materials.     

Thiophosphate/Phosphonate‐Containing Cross‐Linked PEGs and Their Use for the Stabilization of Silver Nanoparticles

A simple strategy was developed to obtain poly(ethylene glycol) (PEG)‐based materials incorporating phosphonate functions and thiophosphate groups from readily accessible symmetrical PEG compounds and trifunctional thiophosphates. These materials are obtained in a two‐step procedure, via the formation of THF soluble, hyperbranched PEG‐based polyazomethines that are subsequently functionalized with dimethylphosphite. The resulting materials are hydrolytically degradable, and upon exposure to aqueous solutions of silver acetate they afford stable colloidal solutions of silver.     

银/聚合物纳米复合材料

银/聚合物纳米复合材料是一种典型的聚合物基复合材料, 其结构和性能依赖于合成方法,因此开发材料的优异性能必须以深入研究纳米材料的先进合成技术为前提。本文综述了纳米银粒子及其与聚合物形成的纳米复合材料的最新合成进展, 重点介绍了基于液相化学还原方法合成纳米银粒子的新方法, 如溶胶-凝胶法、沉淀法、微乳液法和离子液体法, 以及纳米银粒子的分散技术和原位法合成银/聚合物纳米复合材料的新技术, 并介绍了纳米银复合材料的电绝缘性、表面增强拉曼散射性能、抗菌性及其在生物医学等领域中的应用。     

化学增感对苯并三氮唑银的PTG材料感光性能的影响

本文主要研究了传统卤化银照相材料中的增感技术,如硫增感、金增感、硫加金协同增感,对新型的以苯并三氮唑银为银源、水性聚乙烯醇为粘合剂的光敏热成像材料增感是否有效的问题.结果显示,传统化学增感对异位法制备的溴化银为光敏剂的光敏热成像材料具有很好的增感效果,硫加金协同增感的效果要好于单独的硫增感和金增感;传统化学增感对原位法制备的溴化银为光敏剂的光敏热成像材料没有增感效果,反而减感,硫加金减感效果最严重.     

Evidence for bias in measured δ15N values of terrestrial and aquatic organic materials due to pre-analysis acid treatment methods

We investigate the effect of acid treatment methods on δ(15)N values from a range of environmental organic materials in the context of the increased application of 'dual-mode' isotope analysis (the simultaneous measurement of δ(13)C and δ(15)N from the same acid-treated sample). Three common methods are compared; (i) untreated samples; (ii) acidification followed by sequential water rinse (rinse method); and (iii) acidification in silver capsules (capsule method). The influence of capsule type (silver and tin) on δ(15)N is also independently assessed (as the capsule and rinse methods combust samples in different capsules; silver and tin, respectively). We find significant differences in δ(15)N values between methods and the precision of any one method varies significantly between sample materials and above the instrument precision (>0.3‰). The δ(15)N values of untreated samples did not produce the most consistent data on all sample materials. In addition, the capsule type appears to influence the measured δ(15)N value of some materials, particularly those combusted only in silver capsules. We also compare the new δ(15)N data with previously published δ(13)C data on the same materials. The response of δ(13)C and δ(15)N within and between methods and sample materials to acidification appears to be relatively disproportionate, which can influence the environmental interpretation of the measured data. In addition, statistical methods used to estimate inorganic nitrogen are shown to be seriously flawed.     

Interactions of silver with humates and other species in natural waters

Tracer^110mAg has been used to investigate the speciation of silver in natural waters, which may contain chloride, sulphide or humate ions. Silver chloride or oxide is readily absorbed from waters by many materials, and some may be photochemically reduced to metallic silver. Absorbed silver, silver chloride and silver sulphide may be distinguished by their desorption behaviour. Humates form complexes with silver chloride, silver sulphide and the silver cation, which can be separated from smaller species by gel permeation chromatography.     

酞嗪在苯并三氮唑银光敏热显影体系中的作用研究

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进行了研究,结果表明:PHZ加入AgBTA体系中可以起到促进显影的作用,并且该作用随着其用量的增加而增大;AgBTA体系中协同使用PHZ与邻苯二甲酸(H₂PA)的显影促进作用要好于单独使用PHZ的作用;在使用PHZ/H₂PA的AgBTA体系中,PHZ的促进作用与AgBTA乳液体系的pH值相关,在较低pH时,几乎没有促进作用,在较高pH值时,PHZ的促进作用较明显;电镜分析表明,PHZ与AgBTA生成银复合物而发挥显影促进作用.     

Preconcentration of silver from rocks by extraction with bismuth dibenzyldithiocarbamate prior to neutron activation analysis

The method developed for determining trace levels of silver in geological materials involves the extraction of silver with a toluene solution of bismuth dibenzyldithiocarbamate followed by neutron activation of the extract. At pH 2 and in the presence of 0.1M EDTA, silver is quantitatively extracted. Under these conditions only small amounts of copper are coextracted. The detection limits of silver for three different modes of neutron activation analysis: /three cycles with Ge/Li/ detector, one cycle with Ge/Li/ detector and one cycle with NaI/Tl/ detector/ were 12, 20 and 11 ng g^–1, respectively.     

The effect of silver ions and nanoparticles on the properties of ion-exchange materials

The effect of silver ions and nanoparticles on the electrochemical properties of KU-2-8 sulfocationite, MF-4SK homogeneous sulfocationite membrane, and MA-40 heterogeneous anion-exchange membrane is studied. Using scanning electron microscopy, the particle distribution throughout the cationexchanger thickness is studied. The method of IR spectroscopy is used for studying the interaction of silver nanoparticles and ions and also of Cu²⁺ and Ni²⁺ ions with secondary and tertiary amino groups. It is shown that the mobilities of sodium and silver ions are close in sulfocationites, which suggests that silver ions are quickly washed out of such materials. In the anion-exchange membrane, silver ions are bound into complexes with ionogenic groups and induce an increase in the water dissociate rate in the membrane. The reduction of silver ions contained in cation-exchangers in a molar fraction of 80% with sodium borohydride affords a conducting metal silver film on their surfaces. The introduction of silver nanoparticles into the MA-40 anionexchange membrane is accompanied by the increase in both the limiting electrodiffusion current and the water dissociation rate in the membrane, which is apparently due to the partial oxidation of metal silver particles to afford silver oxide in the near-surface membrane layer. The latter oxide exhibits weak catalytic activity with respect to water dissociation reaction in the membrane, which results in an insignificant increase in the effective transport numbers of hydroxide ions through the membrane.     

Silver bromide nanoparticle/polymer composites: dual action tunable antimicrobial materials

We present a simple method of fabricating highly potent dual action antibacterial composites consisting of a cationic polymer matrix and embedded silver bromide nanoparticles. A simple and novel technique of on-site precipitation of AgBr was used to synthesize the polymer/nanoparticle composites. The synthesized composites have potent antibacterial activity toward both gram-positive and gram-negative bacteria. The materials form good coatings on surfaces and kill both airborne and waterborne bacteria. Surfaces coated with these composites resist biofilm formation. These composites are different from other silver-containing antibacterial materials both in the ease of synthesis and in the use of a silver salt nanoparticle instead of elemental silver or complex silver compounds. We also demonstrate the ability to tune the release of biocidal Ag(+) ions from these composites by controlling the size of the embedded AgBr nanoparticles. These composites are potentially useful as antimicrobial coatings in a wide variety of biomedical and general use applications.     

Determination of silver in biological materials by high-frequency plasma-torch emission spectrometry

Nanogram amounts or silver in small samples of biological materials can be determined by high-frequency plasma-torch emission spectrometry. Samples are digested with perchloric and nitric acids, silver is collected with a bismuth iodide carrier, and the precipitate is decomposed with concentrated nitric acid before dilution. Bismuth shows an enhancing effect on the silver emission at 328.06 nm, and the sensitivity is further improved by elimination of moisture in the aerosol with a second condenser at -3 to -5°C. The detection limit is 0.5 ng per 0.2 ml of sample solution. Condensed milk and whole blood were analyzed satisfactorily.     

Crystallization of silver stearate from sodium stearate dispersions

Silver carboxylates, the common silver source used for photothermographic imaging materials, are normally obtained from the reaction between sodium soap (e.g., sodium stearate) and silver nitrate. They form platelet-like crystals with a lamellar structure in water at room temperature. Light microscopy investigations reveal that the formation of silver stearate (AgSt) crystals follows a diffusion-controlled mechanism. The reaction between the sodium soap and silver nitrate preferentially occurs in solution rather than on the soap fiber solid interface. Cryogenic transmission electron microscopy, together with an on-the-grid reaction technique, provides a useful tool to directly image silver stearate microstructures at the initial stages of AgSt precipitation. The AgSt reaction product first forms particles about 5 nm in size, which is similar to the d-spacing of final AgSt crystals. Those particles aggregate to produce larger and loosely packed embryonic crystals, the precursors to the ultimate silver stearate crystals.     

Plasmonic photocatalytic system using silver chloride/silver nanostructures under visible light

Plasmonic photocatalytic nanostructured system was investigated on silver chloride/silver nanoparticles under visible light. Silver chloride/silver nanoparticles were readily prepared using dispersing agent and light irradiation. The d-spacing analysis, high resolution-transmission electron microscopy, X-ray diffraction analysis and diffuse-reflectance spectroscopy demonstrated that silver nanoparticles were introduced on the surface of silver chloride nanoparticles and then silver chloride/silver nanostructured photocatalytic materials were successfully synthesized. The as-synthesized plasmonic photocatalysts exhibited the enhanced photocatalytic performance over nitrogen-doped titania nanomaterials. The improved catalytic activity was originated from the enhanced adsorption for visible light, electron–hole separation, and the formation of chloride atoms in silver chloride/silver nanostructured materials.     

电位滴定法测定火试金得到的金银合粒中的银

本文研究了用自动电位滴定仪测定外购铜物料样品中经火试金熔炼、富集、灰吹后得到的金银合粒中银的方法。金银合粒用硝酸溶解后在自动电位滴定仪上用硫氰酸钾标准溶液滴定银量,选择了仪器的测定条件,考察了溶液酸度、共存元素对测定的干扰。方法相对标准偏差为1.34％～3.62％,测定结果与硫氰酸钾手工滴定法和减杂法相一致。方法的准确度和精密度均能满足分析需要,具有较强的实用性和推广价值。     

Silver pyrazolates as coordination-polymer luminescent metallomesogens

Silver pyrazolates with columnar liquid-crystal phases that are stable at room temperature have been prepared by reaction of silver nitrate with 3,5-diarylpyrazolates. The complexes consist of open-chain oligomers, despite the fact that the most common structural type for homoleptic coinage metal pyrazolates is the trimeric metallacycle [M(μ-pz)](3). The special characteristics of silver in forming reversible metal-ligand bonds in solution, evidenced experimentally, leads to supramolecular organizations in which the silver cations promote self-organization of the nonmesomorphic pyrazolates into helical 1D polymers that exhibit columnar mesophases. The materials are readily soluble in common organic solvents and are liquid-crystalline over a broader temperature range than their gold counterparts, which are known to form discrete cyclic trinuclear species. Thin films of the silver complexes show luminescence at room temperature. The compounds described here are the first examples of luminescent metallomesogens formed by a main-chain coordination polymer.