Stabilization of Sn Anode through Structural Reconstruction of a Cu–Sn Intermetallic Coating Layer

The metallic tin (Sn) anode is a promising candidate for next-generation lithium-ion batteries (LIBs) due to its high theoretical capacity and electrical conductivity. However, Sn suffers from severe mechanical degradation caused by large volume changes during lithiation/delithiation, which leads to a rapid capacity decay for LIBs application. Herein, a Cu–Sn (e.g., Cu₃Sn) intermetallic coating layer (ICL) is rationally designed to stabilize Sn through a structural reconstruction mechanism. The low activity of the Cu–Sn ICL against lithiation/delithiation enables the gradual separation of the metallic Cu phase from the Cu–Sn ICL, which provides a regulatable and appropriate distribution of Cu to buffer volume change of Sn anode. Concurrently, the homogeneous distribution of the separated Sn together with Cu promotes uniform lithiation/delithiation, mitigating the internal stress. In addition, the residual rigid Cu–Sn intermetallic shows terrific mechanical integrity that resists the plastic deformation during the lithiation/delithiation. As a result, the Sn anode enhanced by the Cu–Sn ICL shows a significant improvement in cycling stability with a dramatically reduced capacity decay rate of 0.03% per cycle for 1000 cycles. The structural reconstruction mechanism in this work shines a light on new materials and structural design that can stabilize high-performance and high-volume-change electrodes for rechargeable batteries and beyond.     

Detected contrast and dynamic range measurements of CdZnTesemiconductors for flat-panel digital radiography

The detected contrast and dynamic ranges of Cd_1-xZn_xTe semiconductor detectors have been measured, within the X-ray diagnostic energy range, using a contrast sensitivity phantom. The aim of this study is to optimize the image quality parameters of these solid state ionization devices for flat panel digital radiographic applications. The experimental results of this study indicate that Cd_1-xZn_xTe detectors have excellent detected contrast response and large dynamic range     

Characterisation of molecular beam epitaxy-grown InGaAs multilayer structures using photoluminescence

Molecular beam epitaxy-grown InGaAs/GaAs multilayer structures were used to characterise for their indium composition, quantum well widths and energy levels in quantum wells employing low-temperature photoluminescence spectroscopy. The effect of surface segregation and thermal desorption of indium atoms in these structures which changes the intended square well and barrier profiles is demonstrated. These shape changes in the well and barrier must be taken into account to correctly predict the quantum well energy level positions and hence the indium composition and the quantum well width.     

Analysis of groundwater quality using fuzzy synthetic evaluation

This paper reports the application of fuzzy set theory for decision-making in the assessment of physico-chemical quality of groundwater for drinking purposes. Methodology based on fuzzy set theory used to express the quality of water in the imprecise environment of monitored data and prescribed limits given in a non-probabilistic sense. Fuzzy synthetic evaluation model gives the certainty levels for the acceptability of the water based on the prescribed limit of various regulatory bodies quality class and perception of the experts from the field of drinking water quality. Application of fuzzy rule based optimization model is illustrated with 42 groundwater samples collected from the 15 villages of Ateli block of southern Haryana, India. These samples were analysed for 16 different physico-chemical water quality parameters. Ten parameters were used for the quality assessment using this approach. The analysis showed that four samples were in "desirable" category with certainty level of 35-58%, 23 samples were in "acceptable" category whose certainty level ranged from 37 to 75% and remaining 15 samples were in "not acceptable" category for drinking purposes with certainty levels from 44 to 100%. This concludes that about 64% water sources were either in "desirable" or "acceptable" category for drinking purposes.     

Ultra-violet absorption spectra: 4-hydroxy coumarins

The ultra-violet absorption, in the range 250 mμ—350 mμ, of twelve 4-hydroxy coumarins in methanol and in 10% aqueous methanol over a range of pH, has been studied and discussed.     

Wind induced damage observations and their implications for design practice

A synopsis of wind induced damage observations is presented, along with a commentary on damage documentation experiences and remarks on design implications. The paper concludes with a discussion on problem areas concerning wind effects and the performance of buildings in windstorms.     

Women scientists at work—An international comparative study of six countries

On the basis of survey, conducted within the framework of the UNESCO International Comparative Study on the Organization of Research groups, the role and position of women in scientific activity is compared. Data on a total of (6000 individuals) from Argentina, India, Egypt, Korea, Poland and USSR show that women scientists' participation is highest in Poland, and lower in India, Korea and Argentina. Everywhere women scientists are more often doing the routine aspects of the research process and more isolated from external contacts with men. Women have lower scientific productivity than male scientists which can be interpreted as a consequence of their lower status in the organization.Presented at the XI World Congress of Sociology, August 1986, New Delhi, India.     

Effect of resin chemisorption and crosslinking on various fiber properties of cotton

Chemisorption and crosslinking of cotton cellulose has been carried out with DMEU, DMPU, DHEU, and DMDHEU. Various physicochemical properties of resin-treated samples have been studied and the data subjected to a linear regression analysis. Using the techniques of liquid retention and optical microscopy it has been found that the chemisorbed cotton is characterized by a lower level of bound resin, greater amount of methylol HCHO, and higher swellability of structure in comparison to the crosslinked cotton. This difference of behavior between the two cottons is attributed to greater rigidification and a collapse of porous structure in crosslinked cotton as a result of catalytic activity at the curing temperature. For various resin-treated samples there exists a linear relationship between the strength and recovery characteristics of single fibers and those of fiber bundles. The losses in fiber strength and extensibility are found to be proportional to the level of bound resin in various samples. Crosslinked fibers show appreciably higher magnitudes of elastic recovery and bundle crease recovery than chemisorbed fibers. The significance of these results is discussed.