Systems Silver Iodide-Sodium Iodide and Silver Iodide-Potassium Iodide

The phase relations for the systems AgI-NaI and AgI-KI have been determined for the temperature range from room temperature to 685° C, using differential thermal analysis techniques. The AgI-NaI system has a eutectic at 50 mole percent NaI and 384° C. The AgI-KI system has eutectics at 20.8 and 28.5 mole percent KI and 254° C and 244° C, respectively. A compound of formula KAg₃I₄ is formed with a congruent melting point of 268° C.     

Photolytic Behavior of Silver Iodide

Silver iodide exposed to high intensity radiation in the visible light spectrum was found to yield a powder X-ray diffraction pattern showing marked deviations from ideality. It was found possible to correlate these with a decrease in primary extinction, indicating a constant progress from an ideal to a mosaic type crystallinity. Large single crystals showed pronounced asterism in transmission Laue photographs under similar experimental conditions. Small amounts of colloidal silver were detected. A mechanism for this process in silver iodide is proposed, in general agreement with the theory of the photographic process. The primary difference from the other silver halides appears to be a considerably slower rate, permitting the observation of a two step process in detail.     

Silver Iodide Formation in Methyl Ammonium Lead Iodide Perovskite Solar Cells with Silver Top Electrodes

Silver is a low‐cost candidate electrode material for perovskite solar cells. However, in such cells the silver electrodes turn yellow within days of device fabrication. The color change is also accompanied by a dramatic decrease in the power conversion efficiency when compared to otherwise identical devices using gold electrodes. Here, it is shown that the color change results from silver oxidation to silver iodide, due to a reaction with iodine in methyl ammonium lead perovskite. The change in X‐ray diffraction and X‐ray photo­electron spectroscopy is discussed. Exposure to air accelerates corrosion of the Ag electrodes when compared to dry nitrogen gas exposure. However, iodine not reacted with silver is observed by X‐ray photoelectron spectroscopy even for the perovskite solar cell kept in dry nitrogen gas. It is proposed that silver iodide is formed when methyl ammonium iodide migration is facilitated by the small pinholes in the hole transport layer spiro‐MeOTAD.     

Factors Influencing the Response of Silver Iodide Emulsions

Contrary to the conclusions of previous authors, it is shown that silver iodide emulsions may be sulphur sensitized. Additional large increases of speed for exposures at moderate and low intensity may be achieved by bathing in water, solutions of halogen acceptors, or silver nitrate before exposure, or by coating at low pAg. In agreement with the observations of some authors, a silver iodide emulsion can form an internal image. In conformity with this capacity to form an internal image. the emulsion exhibits solarization.     

Electron Microscope Studies on the Forn1ation of Silver Filaments from Silver Iodide Crystals

The growth of filamentary silver from microcrystals of silver iodide has been examined in the electron microscope. It was found that filamentary growth was restricted to certain types of crystals namely those containing twin planes. After growth the filaments exhibited contrast bands which appeared to be connected with prismatic slip. A mechanism is put forward, based on twinning dislocations, to explain the mode of generation of filaments.     

Interface-Stabilized States of Silver Iodide in AgI–Al2O3 Composites

AgI–Al₂O₃ nanocomposites are investigated by high-resolution electron microscopy and luminescence spectroscopy. The results show that both crystalline and amorphous phases coexist in AgI–Al₂O₃ composites. At sufficiently high alumina content, almost all AgI occurs as amorphous spherical nanoparticles distributed uniformly on alumina surfaces. The amorphous phase exhibits unusual luminescence spectra with a single, very broad nonstructured band. The amorphous phase is stabilized on AgI–alumina interfaces with the relative concentration progressively increasing with the Al₂O₃ fraction. The thickness of the interface amorphous layer adjacent to Al₂O₃ particles estimated by means of a simple brick-wall model is about 3 nm.     

碘化钾在溴化银晶体生长中的作用

本文通过在乳化过程中对碘化钾加入位置的调整研究了碘化钾对颗粒形态比以及照相性能的影响,得出了随着碘化钾在溴碘化银晶体的外移,晶体的形态比逐渐增大,并且在一定形态比的范围内乳剂的感光度随着颗粒的增大而增加的结论。     

不锈钢冷加工形变诱发马氏体相变及其腐蚀行为

在实验室和现场对经过不同温度，不同方式，不同程度冷加工的奥氏体304不锈钢进行马氏体相变量的检测，研究了冷加工与马氏体相变的关系。通过浸泡试验和金相显微镜研究了304不锈钢在腐蚀过程中马氏体含量的变化。结果表明，冷加工能产生不同程度的马氏体相变；在腐蚀过程中，马氏体相存在优先溶解。     

Silver‐Assisted Synthesis of Gold Nanorods: the Relation between Silver Additive and Iodide Impurities

Seed‐mediated methods employing cetyltrimethylammonium bromide (CTAB) as a surfactant, and silver salts as additives, are the most common synthetic strategies for high‐yield productions of quality Au nanorods. However, the mechanism of these reactions is not yet fully understood and, importantly, significant lab‐to‐lab reproducibility issues still affect these protocols. In this study, the direct correlation between the hidden content of iodide impurities in CTAB reagents, which can drastically differ from different suppliers or batches, and the optimal concentration of silver required to maximize the nanorods yield is demonstrated. As a result, high‐quality nanorods are obtained at different iodide contents. These results are interpreted based on the different concentrations of CTAB and cetyltrimethylammonium iodide (CTAI) complexes with Ag⁺ and Au⁺ metal ions in the growth solution, and their different binding affinity and reduction potential on distinct crystallographic planes. Notably, the exhaustive conversion of CTAI–Au⁺ to CTAI–Ag⁺ appears to be the key condition for maximizing the nanorod yield.     

内燃机挺杆疲劳磨损过程的X射线研究

对三种合金铸铁挺杆进行了冷拖发动机台架试验,用X射线衍射方法对表面织构,衍射线宽化以及上述台架试验中各阶段的表面残余应力分别进行了测定,通过比较三种挺杆的测定结果可以得出:影响挺杆接触疲劳寿命的因素之一为滑移系统相对于摩擦面的取向;疲劳寿命不同,表面残余应力在整个磨损过程中的变化方式和碳化物的保留程度均有所不同,本文对上述实验结果,在弹—塑性裂纹模型的基础上进行了讨论。     

Investigation of Backscatter X-Ray Imaging Techniques for Uranium Dioxide Fuel Rods

Radiography by selective detection (RSD), was investigated for its ability to determine the presence and types of defects in a UO₂ fuel rod surrounded by zirconium cladding. Images created using a Monte Carlo model compared favorably with actual X-ray backscatter images from mock fuel rods. A fuel rod was modeled as a rectangular parallelepiped with zirconium cladding, and pencil beam X-ray sources of 160 kVp (79 keV avg) and 480 kVp (218 keV avg) were generated using the Monte Carlo N-Particle Transport Code (MCNP) to attempt to image void and palladium (Pd) defects in the interior and on the surface of the fuel pellet. It was found that the 160 kVp spectrum was unable to detect the presence of interior defects, whereas the 480 kVp spectrum detected them with both the standard and the RSD backscatter methods, though the RSD method was very inefficient. It was also found that both energy spectra were able to detect void and Pd defects on the surface using both imaging methods. Additionally, two mock fuel rods were imaged using a backscatter X-ray imaging system, one consisting of hafnium pellets in a Zircaloy-4 cladding and the other consisting of steel pellets in a Zircalloy-4 cladding which was then encased in a steel cladding (a double encapsulation configuration employed in irradiation and experiments). It was found that the system was capable of detecting individual HfO₂ pellets in a Zircaloy-4 cladding and may be capable of detecting individual steel pellets in the double-encapsulated sample. It is expected that the system would also be capable of detecting individual UO₂ pellets in a Zircaloy-4 cladding, though no UO₂ fuel rod was available for imaging.     

可见光辐照下碘释放现象超声效应的实验研究

1引言 超声波辐照水溶液时,空化泡在声波的作用下形成、振荡、生长、收缩至崩溃.空化泡崩溃时在空化泡周围的极小空间内可以产生5000K以上的高温和高达5×107pa的高压等极端物理条件,同时可以产生氧化电位很高、化学性质十分活泼的羟基自由基(·OH)[1].利用声空化发生时产生的物理化学条件,通过进行超声预处理,可产生一系列声化学效应如超声诱导效应等,提高反应的产率和速率[2,3].本文研究了碘化钾溶液在可见光辐照下碘释放现象的超声效应.实验结果表明:超声的预辐照可以大大增加碘释放量.我们采用临界模型对该现象进行了初步分析.     

Experimental Investigation of Strain Concentrations Caused by Inserts in Sandwich Beams

Abstract:  This paper presents an experimental study of the strain concentrations developing across the insert–core junctions in a sandwich beam with an implanted stiff insert into its core. Strain measurements were carried out at several positions on the skins and across the insert–core junction, for several sandwich beam specimens loaded in 3-points bending and having inserts with various geometries. The materials used were typical marine glass/polyester composite and PVC foams and the specimens were manufactured with the vacuum infusion method. A full material characterization was performed for the composite skins. The experimental results demonstrated a pure linear bending response of the specimens, as well as significant strain concentration factors across the insert–core junction, reaching values up to 3.3. Strain concentration factors measured for butt inserts were lower than those measured on the tension side of the specimens with scarf inserts. Transverse strains measurements verified that all specimens were in a plane stress state.     

用纤内Bragg光栅进行动态应变测量的研究

描述了用纤内Bragg光栅进行动态应变测量研究的意义，原理和方法，提出了两种用纤内Bragg光栅动态应变测量时进行Bragg波长偏移量的解调方法；光干涉相位检测Bragg光栅反射波长偏移的解调方法和用DWDM密集波分复用器解调Bragg波长的方法，前者适用于高频宽带动态应变测量，后者适用于有限频率或中等频率响应的动态应变测量。     

Electrical Investigation of Some Silver Containing Ceramics Obtained from Coprecipitated Oxalates

1.IlltroductionIntherecentyearsltheneedforhighpurityceramicmaterialsforelectronicindustrieshasledtothewideuseofsol-gel[l]andcoprecipitationtechniquesl2'3l.Intheprecipitationfiltrationtech-nique,themetalionsaresimultaneouslyprecipitatedintheexpectedstoichiometricproportions.There-after,theprecipitateisfilteredoff,washedanddried.Insomecasesasinglephasesolidsolutionprecipitatesassuringhomogeneity.However,evenifsegregationoccursduringprecipitationthedegreeofmixingisfarsuperiortothatobtainedwithco…     

Long-range Correlations in Iodide Cluster Aggregates

The morphology of tin iodide deposits grown during gas-solid transformation demonstrated longrange correlations. These iodide deposits include basically two kinds of forms: fractal structure and dendritic-like structure. The fractal structure was a sort of tin iodide cluster aggregation.Each fractal structure was composed of numerous tin iodide clusters that connected or disconnected with each other. The average size of fractal structures is between 10 and 22 μm. The dendritic-like structure was also composed of many tin iodide clusters. These clusters aggregated and formed a dendritic pattern     

Experimental Investigation of Strain Behaviour of Heated Cement Paste and Concrete

The material degradation of concrete subjected to fire events has a severe influence on the load‐carrying capacity of support structures. Spalling of concrete layers, exposing the reinforcement bars and degradation of the material properties (Young's modulus, compressive strength) may lead to significant damage of the reduced cross‐section and, therefore, cause failure of the structure. In order to understand the stress build‐up at the heated surface caused by thermal expansion due to fire loading, finally leading to damage and spalling of concrete, the strain behaviour of cement paste and concrete exposed to combined thermo‐mechanical loading is the focus of this work. Hereby, the evolution of thermal strains, Young's modulus and Poisson's ratio with increasing temperature are investigated experimentally. For this purpose, the specimens are loaded uniaxially while the temperature is increased up to 800 °C. The obtained results provide the proper basis for the development of realistic material models, allowing more sophisticated simulations of structures exposed to fire.