Impact of Calcium and Methionine on the Variability of a Sulphur and Gold Sensitization on a Bromoiodide Emulsion

Abstract

Chemical sensitization uniformity requires tight batch-to-batch control of components of gelatin as well as the non-gelatin components that are present. Chemical sensitization sensitivity to variations in methionine and calcium was examined using a bromoiodide emulsion at fixed levels of sulphur and gold sensitizer. Hydrogen peroxide treatment of gelatin was used to generate a series of partially oxidized gelatins with varying methionine content. Calcium variation was examined by choosing gelatin with known natural variations in calcium and by addition of calcium salts to deionized gelatins. Sensitometric changes were seen as a function of both calcium and methionine variation. Results indicate that methionine and calcium must be carefully controlled to minimize photographic change.     

Electromagnetic interference shielding,mechanical properties and water absorption of copper/bamboo fabric (Cu/BF) composites

Copper/bamboo fabric (Cu/BF) composites were prepared by electroless deposition via a tin-free process. The process involved 3-aminopropyltrimethoxysilane modification, noble metal (Au or Pd) activation and electroless copper planting of BF. The copper deposition rate via Pd catalytic process was 1.01 mg/cm² h, higher than that by Au catalytic process (0.85 mg/cm² h). The microstructure of Cu/BF composites was analyzed by scanning electron microscopy (SEM), and the copper coatings were composed of ball-shaped copper particles. The composition and chemical state of copper layers were measured by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) spectra, Cu⁰ was detected but copper dioxide was not found in both spectra. The electromagnetic interference, water absorption, mechanical tension, conductivity and adhesion properties of Cu/BF samples (weight ratio of Cu/BF: 0.36 ± 0.01) were measured to obtain the qualities of the composites.     

Silica SBA-15 template assisted synthesis of ultrasmall and homogeneously sized copper nanoparticles

The synthesis of spherical copper nanoparticles with extremely narrow size distribution by electroless copper deposition on mesoporous silica support is described. The materials were characterized by nitrogen sorption, transmission electron microscopy, x-ray diffractometry and Fourier transform infrared spectroscopy. The copper nanoparticles have a cubic crystalline structure and an average particle size of 5.5 +/- 0.8 nm. The copper nanoparticles are stable, without detectable oxidation or further agglomeration under ambient conditions even after months. These results demonstrate that electroless copper reduction can be conducted and constrained within the mesoporous silica framework, which pave the way for engineered mesoreactors.     

Preparation of gold clusters in gelatin layer film using photographic film — 4: Effect of photographic materials

Abstract

The effect of the properties of photographic materials on the preparation of gold clusters in a gelatin layer using a photographic film was examined. The cluster are formed by reducing a gold(I)–thiocyanate complex solution on latent image specks in emulsion grains. Gold clusters are marked as a non-linear optical material, and it was necessary for this purpose to condense the gold clusters in the layer. This was attempted by two methods. The first was to increase the emulsion grains in the layer, and the second was to increase the number of latent image specks on a grain. An ultrafine grain emulsion was applied for the former, while a high-intensity exposure and chemically sensitized emulsions were used to induce the dispersion of latent image specks for the latter. The characteristics of the clusters prepared from those emulsions were compared by absorption spectrum and size distribution. Both methods increased the plasmon absorption due to the gold clusters. The size of the clusters was similar, while absorbance increased with the sulphur-sensitization level. These results suggested that both were effective in condensing the gold clusters in the layer.     

Silver Halide (Sensitized) Gelatin in Agfa-Gevaert Plates: The Optimized Procedure

Abstract

Silver halide sensitized gelatin (SHSG) is one of the most promising techniques for the fabrication of transmission holographic optical elements, achieving relatively high sensitivity of photographic material with the low scattering and high light stability of dichromated gelatin. In this paper we present the optimized procedure in Agfa-Gevaert plates. Diffraction gratings with a diffraction efficiency up to 80% and a noise level of less than 1% are obtained with a sensitivity 10³ times better than dichromated gelatin.     

Microstructure and friction performance of copper film fabricated by ion implantation assisted electroless plating on PTFE

Abstract

The polytetrafluoroethylene (PTFE), which was implanted with Ni ion to different energy and doses, fabricated metallic structures by selective electroless copper plating. The characteristic and microstructure of the copper film were studied using SEM and X-ray diffraction. Friction performance of the interface between copper film and basal body of PTFE was tested with a CETR UMT-2 (CETR Co., Campbell, CA, USA) multifunction micromechanics instrument. The test loads were 10, 20 and 40 N, while the line velocity was 8 mm s^?1, and the frequency of data acquisition was 1 Hz. The Ni ion implantation replaces the complicated electroless plating surface pretreatment, and it is an assisted technique of electroless plating of copper on the surface of PTFE and plate Cu directly on its surface. Continuous, prepressing and uniformity plating was obtained with proper technique parameters and the dosage of Ni⁺. The frictional performance comprehensive property of copper film was remarkably influenced by different plating methods, annealing treatment and testing loads under unlubricated condition. The friction coefficients and wear rates changed with the varied load. Annealing treatment improves the tightness and uniformity of the copper film, while it decreases its cavity. Friction performance of copper film was thus increased. The mechanisms of friction and wear of copper film under different test conditions are also discussed.     

Electroless copper plating on 1,2-ethylenediamine grafted poly(ethyleneterepthalate) for the fabrication of flexible copper clad laminate

An efficient method for the fabrication of flexible copper clad laminate (FCCL) on poly(ethyleneterepthalate) (PET) sheet by electroless plating was developed. This method relies on PET surface grafted 1,2-ethylenediamine (EDA) layer, which is employed as an adhesive interlayer for the manufacture of FCCL. Au catalysts were adsorbed on the EDA treated PET sheet and subsequently initiate the deposition of copper in an electroless plating solution. Attenuated total reflection fourier transformation infrared (ATR-FT-IR) spectroscopy, water contact angle, X-ray photoelectron spectroscopy, and atomic force microscope were employed to trace the surface changes during the grafting process with water, ethanol or dimethyl sulfoxide (DMSO) as solvent. For the PET sheets grafted from ethanol and DMSO solution, the prepared copper layers show strong adhesion to the substrate, which can pass Scotch^® tape test, while the sample grafted from water solution fail. All results indicate that using ethanol or DMSO as solvent for EDA grafting is benefit for the preparation of FCCL, and the adhesive improvements are due to an increase in the surface roughness of PET sheets and the amount of gold particles adsorbed on PET surface which act as nucleation and anchor sites for copper.     

Growth of copper on diatom silica by electroless deposition technique

In this study, the growth of copper on porous diatom silica by electroless deposition method has been demonstrated for the first time. Raman peaks of copper (145, 213, and 640 cm^?1) appeared in the copper-coated, Amphora sp. and Skeletonema sp. diatom samples, confirming the successful deposition of copper. Scanning electron microscopy (SEM) indicated the presence of copper on the diatom silica surface. The 3D intricate structure of diatom was still evident by optical and scanning electron microscopy analyses when the diatom samples were immersed in the copper bath for only 5 hours. Incubating the diatom samples in the copper bath for 24 h produced a dense coating on the diatom surface and covered the intricate 3D structure of the diatom silica. These results present possibilities of the fabrication of hierarchically organized copper with 3D diatom replica structures.     

Fabrication of conductive copper-coated glass fibers through electroless plating process

A simple electroless copper plating process was employed to prepare copper-coated glass fibers with excellent conductivity. The glass fibers were pretreated by etching, sensitizing, and activating procedures. Disodium ethylenediamine tetra acetate (EDTA-2Na) and hydrazine hydrate (N₂H₄·H₂O) were employed as complex reagent and reductant, respectively. It was found that the copper deposition was greatly influenced by dosage of EDTA-2Na, concentration of sodium hydroxide (NaOH), temperature, and volume of N₂H₄·H₂O. The optimal temperature for electroless copper plating ranged from 40 to 60 °C. The composites were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy techniques. The result showed that the minimum volume resistivity of 0.0010 Ω cm was obtained for the sample with perfect copper coatings on the surface of glass fibers. This method is simple, low-cost, and large production, and can be extended to fabricate other metal-coated glass fibers with distinct conductivity.     

Change in the Molecular Weight Distribution of Gelatin by a High Pressure Slurry Jet

Abstract

Physical and photographic properties of gelatin depend on the molecular weight distribution of the gelatin, which it is important to control. We controlled the molecular weight distribution of gelatin by pressurizing the sample gelatin solution and jetting it at high velocity from a nozzle to a collision plate. II was found that this method teas effective in controlling the molecular weight distribution of gelatin and in preparing a gelatin which contains mainly ± and β components and few high and low molecular weight components.     

How to Orient Collagen and Gelatin

Abstract

The arrangement of triple helical domains of gelatin molecules may have important physical consequences in photographic gelatins. We review work which indicates that lyotropic liquid crystallization is important in defining molecular orientation and packing in collagens and suggest that it would be worth looking for similar effects in gelatins under certain conditions. We present a preliminary observation which suggests that gelatin can actually behave as a liquid crystal. The possible role of lyotropic liquid crystallization in photographic manufacturing and the interaction of gelatin with other photographic components, such as silver halide, needs further investigation.     

Effects of N02 and S02 on the Degradation of Photographic Gelatin

Abstract

The degradation of photographic gelatin exposed to a mixture of two pollutant j gases, NO₂ and SO₂, was investigated by swelling measurements and steric I exclusion high performance liquid chromatography. The study, performed on one unhardened gelatin and two hardened gelatins, showed that all three are sensitive to pollutants. Two major effects were noted: the first was an increasing of the swelling of the gelatin films in deinineralized water and the second effect was a change in the steric exclusion chromatographic profile, corresponding to a shift to smaller molecular weights. Both these phenomena indicate that the pollutant gases induce hydrolysis of the gelatin macromolecules. Nevertheless, for the same exposure, the hardened gelatins are shoum to be less degraded than the unhardened one. Thus, even if it does not protect the photographic gelatin totally from attack by the pollutant gases, hardening slozos down its deterioration.     

Acid Ossein Gelatin

Abstract

The properties and manufacture of acid ossein gelatin are discussed with particular reference to the use of acid ossein gelatin in the photographic and allied industries.

The effect that the demineralizing process has on the properties of the gelatin extracted has been investigated with different demineralizing media. Loss of amide ammonia during the commercial demineralizing of bone has been confirmed and the rate of this toss has been studied using calcium and ammonia analyses. Different types of acid or lime processed gelatins can be distinguished also by analysis of their titration curves. From both experimental and calculated titration curve data, some correlations are found xvith gelatin amide content and isoelectric point.

A literature review is given, highlighting some of the applications found for acid ossein gelatin in the photographic industry.     

Electroless deposition of superconducting MgB2 films on various substrates

The superconducting properties of magnesium diboride (MgB₂) films prepared by electroless deposition on various substrates including silver, gold and silicon are reported. In this study, MgB₂ films were fabricated on silver, gold, and silicon using an electroless plating technique, while controlling the redox potential to improve the deposition quality. The structure, morphology, and superconducting properties of the samples were investigated using X-ray diffraction, magnetometry, scanning electron microscopy, and Raman spectroscopy. X-ray diffraction and Raman spectroscopy confirmed that the films are polycrystalline MgB₂ but also contain some impurity phases. All the MgB₂ films show superconducting transitions near 39 K, the value for bulk MgB₂, with the superconducting volume fraction ranging from approximately 1 to 2%. We find a strong dependence of film quality with the oxidation potential of the bath.     

Atmospheric pressure plasma liquid deposition of copper nanoparticles on poly(4-vinylpyridine)-grafted-poly(tetrafluoroethylene) surface and their autocatalytic properties

We demonstrate catalyst-free electroless deposition of copper on a poly(4-vynylpyrridine)-grafted-poly(tetrafluoroethylene) surface. The principle of this process relies on deposition of an organo-copper(II) precursor film on the functionalized polymer surface and on subsequent plasma-assisted reduction of the copper ion to form nanoparticles. A polymer surface densely and homogeneously seeded with copper nanoparticles enable to initiate autocatalytic electroless deposition of copper layer without need for any prior sensitizing the surface with conventionally used SnCl₂ and Pd species.     

仿金镀中超声波的作用

超声波在化学镀尤其是仿金镀方面对操作参数、镀层质量作用很大,但其应用报道甚少.为了找出超声波在化学镀中的一般规律,揭示其对仿金电镀中化学镀镍及Cu2+,Zn2+和Sn2+的沉积机理,考察了超声波对仿金镀活化、化学镀镍、仿金镀电镀过程等各阶段多种因素的影响,包括活化工艺、pH值、电流密度、还原剂用量、配位剂用量等;优化了试验条件.结果显示,仿金镀工艺中引入超声波,降低了施镀的温度,提高了仿金镀的沉积速率.最后详细研究了超声波所产生的超声空化等对沉积速率、镀层质量以及仿金镀其他过程的作用机理.     

Degradation of Gelatin in Historical Photographs

Abstract

In order to study age related changes in photographic gelatin toe analysed black-and-white roll film before and after accelerated ageing and samples of naturally aged glass plate negatives. Two-dimensional gel electrophoresis (2D-PACE) was used to separate collagen chains In the gelatin by isoelectric point (pi) and molecular weight. The results shoiv that the x-chatns break down into smaller fragments on ageing. Amino acid analysis ivas performed to examine the oxidative deterioration of gelatin. It shows that the amount of lysine decreases with age.     

基于EDTA-Cu的柔性阴极制备试验与机理研究

为制备低成本和环保的柔性阴极,研究柔性电极的制备机理,本文以EDTA-Cu为活性材料,利用激光诱导化学镀铜工艺,制备了电解加工柔性阴极并进行了系统表征,对相关机理进行了探讨.试验结果表明,基于EDTA-Cu和改性聚氨酯的柔性阴极具有较好的激光诱导化学镀铜选择性,活性材料的成分和颗粒形貌、激光功率、扫描速度、激光波长、激...     

Carbopol-Gelatin Coaceevatioh I Influence of Some Variables

Abstract

The extent and integrity of mloroenoapsulation is hypothesised to be dependent on the optimisation of sediment weight and volume. This led to the investigation of the effeota of the type of gelatin or carbopol, the ratios of the coaeervate materials, the total colloid concentrations, the starting pH of gelatin sol and the stirring rate. Investigation showed that gelatin, type A, at pH 6.8 together with oarbopol 941 gave best results. Optimum oarbopol-gelatln ratio was found to be 1/10, above whioh the sediment weight and volume decreased significantly. Increase in the total oolloid concentration results in a parallel increase in sediment weight till concentration of 1.1% w/v above whioh the increase in sediment weight was less pronounoed. A stirring rate of 300-350 r.p.m. gave an almost spherical, uniform coacervatos with averages diameter of 59 u.     

Electrochemical detectors prepared by electroless deposition for microfabricated electrophoresis chips

Microfabricated capillary electrophoresis (CE) chips with integrated electrochemical detection have been developed on glass substrates. An electroless deposition procedure was used to deposit a gold film directly onto the capillary outlet to provide high-sensitivity electrochemical detection for catechol and several nitroaromatic explosives. Scanning electron microscopy revealed that the electroless gold film contains nanoscopic gold aggregates (100-150 nm) with an average thickness of 79 nm. The electroless deposition procedure can be easily and routinely performed in any wet-chemistry laboratory, and electroless gold can be deposited onto complex and internal surfaces. Intimate coupling of electrochemical detection and CE chips obviates the need for a coupling mechanism or tedious alignment procedures. With nitroaromatic compounds as a working model, microchip capillary electrophoresis equipped with electroless gold has proven to provide high sensitivity and fast response times for sensor applications. The CE microchip system was capable of separation and determination of explosive compounds including TNT in less than 130 s with detection limits ranging from 24 to 36 microg/L, i.e., 4-fold enhancements in detection efficiency in comparison to thick-film technology.