Superconducting materials research in the Peoples' Republic of China

Research projects into superconducting materials are being conducted in the Peoples' Republic of China. The research at various Institutes is described, following a recent visit there.     

Calibration of pressure sensors in an industrial environment

National Measurements Institutes calibrate vacuum pressure sensors a few gauges at a time in a time-consuming fashion, resulting in an accurate calibration with small uncertainty estimates. A manufacturer produces a comparatively large number of sensors a day which must be economically calibrated. Here, we investigate a procedure for rapid calibration of combination vacuum gauges while following as closely as possible the relevant norms published by the international standards organizations. The investigated procedure increases the uncertainty estimate by up to 10%, but the gauges are still within common accuracies (<15% of reading in the range of 1×10⁻⁶ to 1×10⁻² hPa) for this type of measurement instrument.     

Permittivity and permeability measurements using striplineresonator cavities-a comparison

The permittivity and permeability of five materials were measured during a comparison of the stripline resonator cavity technique. The National Institute of Standards and Technology (NIST) organized this intercomparison in which a total of seven organizations participated. Each participant measured two dielectric materials and three magnetic materials. Results for this comparison suggest that when the stripline resonator is used, dielectric property measurements are not as accurate as magnetic property measurements, provided that a correction for demagnetization is made. The results are compared to 7 mm coaxial transmission line measurements which have an uncertainty of less than 10% for the relative permittivity, ϵ_r'<15     

Thesen und Trends &#x0096; Mit funktionalen Oberflächen in die Zukunft

Propositions and Trends &#x0096; With Functional Surfaces into the Future Functional surfaces are the key to innovative products. Already today the properties, lifetime, and costs for most industrial and consumer products are determined by functionalised surfaces. Three Fraunhofer Institutes supported by the BMBF investigated the actual state of the art of production technology regarding functional surfaces, their future perspectives and the research and development demand. The results are published in the study “Production technology for the generation of functional surfaces” available at info@ist.‐ fraunhofer.de and the essentials are summarised in this article.     

Zwitterionic diaminodicyanoquinodimethanes with enhanced blue-green emission in the solid state

Diaminodicyanoquinodimethane molecules which show strong solid state emission in the blue-green region are developed. The new materials are structurally characterized; extended supramolecular assemblies mediated by H-bond interactions are observed in the crystal lattice. Spectroscopic studies including life-time and fluorescence quantum yield measurements in the solution and solid states are carried out. Emission in the solid state is ∼400 times stronger than that in solution; this can be attributed to the inhibition of the excited state geometry relaxation to a non-radiative state, in the solid. Impact of the molecular structure in the crystals on the solid state light emission is discussed. Semiempirical computational studies provide useful insight into the various structural and spectroscopic features of the new materials. The present observations serve as a pointer to further design strategies for realizing novel blue photoluminescent molecular materials based on the diaminodicyanoquinodimethane framework.     

Effect of low temperature on plastic deformation in structural materials in a complex state of stress

The results of experimental studies of elastoplastic deformation in structural materials of different grades in a complex state of stress at low temperatures are analyzed. It is shown that the degree of the effect of temperature and force conditions on the character of materials’ strain hardening at low temperature depends on their nature and structural state. The principal hypotheses and postulates that form the basis of the modern plasticity theories are examined for low temperatures. Two new models are introduced to describe the elastoplastic deformation of quasi-brittle and metastable materials under the simple loading with consideration for the effect of low temperatures on their structural state and mechanical properties.     

State of the metrological service for oil product supply

The current state of the metrological service is considered for oil product supply, together with ways of overcoming the crisis in this area and the role of organizations under the Rosneft' state industry.Translated from Izmeritel'naya Tekhnika, No. 6, pp. 62–63, June, 1995.     

An internal state variable approach to constitutive theories for granular materials with snow as an example

In this paper, a microphysical constitutive theory is developed for a class of rate dependent granular materials under finite deformation. The theory is based on non-equilibrium thermodynamics with internal state variables. The state variables may be thought of as representing the current pattern of microstructural arrangemenp and hence characterize the plastic state of the material. A significant feature of this theory is that the state variables are identified at the granular level, as opposed to the crystalline level. This allows one to develop a microdynamical theory in terms of experimentally observable quantities and is a unique feature of granular materials.The theory is used to describe the mechanical properties of snow under high rate multiaxial deformation. Snow is a highly nonlinear, rate dependent material which exhibits significant microstructural alternations under finite strain. These alternations are tracked mathematically by temporal evolution equations governing the internal state variables. The change in the state variables is directly related to the plastic strain of the material.     

Ferroelectric films and their device applications

Recent reseach on ferroelectric films is discussed, with emphasis on preparative problems, optimization of film structure and of electrical properties and application in devices. Rapid progress has been made in each of these research areas and this fact, together with the emergence of certain new materials such as polyvinylidene fluoride (PVF₂), is increasing the variety of possible applications to solid state devices. Typical examples considered here include microwave capacitors, thermistor bolometers, pyroelectrics, piezoelectric transducers, memories and optical display devices. The present state of the art for these applications and materials development needed for further progress are reviewed.     

光子学材料及其发展

信息技术的基础正在经历从电子学、光电子学到光子学的发展，二十一世纪将是光子信息时代。由于信息技术要求高速度，因此光子学材料要求有短的时间响应，宏观上要求低维，易于光集成，微观上希望是纳米尺寸的复合。本文综述了几种光子学材料的发展，重点介绍了激光材料和光子存储材料。     

论中国包装工业的可持续发展

中国包装工业可持续发展面临包装废弃物处理、水环境污染、大气污染、持久性有机物污染等严重问题,目前国内外有许多企业和组织通过包装减量化、包装的重复使用、材料循环再生与能量回收利用、包装废弃物的生物降解和堆肥等途径努力开发和实现了绿色包装,实际上这也是中国包装工业最终实现可持续发展的有效途径。     

股份制与非股份制组织中上下级工作冲突处理方式的差异

为了分析股份制与非股份制组织员工上下级工作冲突处理方式的各自特点,采用自编的上下级工作冲突处理方式量表,有效测试了254名员工。结果发现,两类组织中都是下属更多采用退让方式,领导更多采用对抗方式;与股份制企业相比,非股份制组织员工更倾向于采用退让方式;协调的处理方式在非股份制组织中更多为领导所采用,股份制比非股份制组织的下属更倾向于采用协调方式。结果提示两类组织中上下级工作冲突处理方式既因民族文化而有共同之处,也因组织文化而有所不同。     

Molecular simulations to understand and to design porous organic molecules

In this short review, we discuss the recent application of molecular modelling and electronic structure calculations to the study of porous organic molecular materials. We focus on the particular challenges to modelling porous materials comprising discrete organic molecules in comparison with framework materials that are interconnected in 3-dimensions by chemical bonds. We also highlight the modular nature of porous molecular organic crystals, and illustrate the potential of small scale calculations on individual units to yield insights into the solution phase and solid state behaviour of these materials. Finally, we discuss the future for this growing field, which promises in the longer term the use of simulations as a design tool for crystal engineering of porous molecular solids.     

Powder-Based Additive Manufacturing: A Critical Review of Materials,Methods, Opportunities,and Challenges

As a 0D material, powder particles can be used to create almost any complicated engineering component by utilizing the high-performance manufacturing capabilities of additive manufacturing (AM). Although powder-based AM methods provide an outstanding practical value and development for modern manufacturing world, they continue to face challenges such as a lack of accessible categories, temperature restrictions, and poor performance of molded components. Therefore, researching for new AM materials and procedures has become an extremely necessary endeavor. For this purpose, a firm grasp of the current state of the art of powder-based AM technologies is imperative. Hence, herein, a comprehensive review is presented on the most widely used powder-based AM methods, and the materials used by these methods. For each method, the development and current state, operating principles, limitations, and future prospects are summarized. In contrast, for materials, their classifications, properties, and preparation methods are explored in great detail, while also commenting on the specific compatibilities between powder materials and powder methods. Industrial and commercialized applications of powder-based AM are also presented in this work. Finally, the limitations of the current powder-based technologies are highlighted, with comments regarding the future of this field.     

The Potential of Proteins for Producing Food Packaging Materials: A Review

The problems associated with obtaining conventional plastic materials and with their accumulation have led to a constant search for new materials derived from renewable sources. Materials made from proteins stand out among them all because of the many ways in which they can be modified enzymatically, chemically or physically, giving rise to materials with improved physicochemical properties that are adjustable to each specific application. This paper reviews the state of the art with regard to the use of proteins for the manufacture of packaging materials, including: the main protein sources that have been used; manufacturing methods (coating on conventional materials, thermoforming, extrusion), with special emphasis on materials made by extrusion; possible strategies for improving the physicochemical properties of the materials and the main future prospects and limitations of materials of this kind.     

Micrometer-level naked-eye detection of caesium particulates in the solid state

Abstract

Large amounts of radioactive material were released from the Fukushima Daiichi nuclear plant in Japan, contaminating the local environment. During the early stages of such nuclear accidents, iodine I-131 (half-life 8.02 d) is usually detectable in the surrounding atmosphere and bodies of water. On the other hand, in the long-term, soil and water contamination by Cs-137, which has a half-life of 30.17 years, is a serious problem. In Japan, the government is planning and carrying out radioactive decontamination operations not only with public agencies but also non-governmental organizations, making radiation measurements within Japan. If caesium (also radiocaesium) could be detected by the naked eye then its environmental remediation would be facilitated. Supramolecular material approaches, such as host–guest chemistry, are useful in the design of high-resolution molecular sensors and can be used to convert molecular-recognition processes into optical signals. In this work, we have developed molecular materials (here, phenols) as an optical probe for caesium cation-containing particles with implementation based on simple spray-on reagents and a commonly available fluorescent lamp for naked-eye detection in the solid state. This chemical optical probe provides a higher spatial resolution than existing radioscopes and gamma-ray cameras.     

Materials selection using complex proportional assessment and evaluation of mixed data methods

Material selection is a very fast growing multi-criteria decision-making (MCDM) problem involving a large number of factors influencing the selection process. Proper choice of material is a critical issue for the success and competitiveness of the manufacturing organizations in the global market. Selection of the most appropriate material for a particular engineering application is a time consuming and expensive process where several candidate materials available in the market are taken into consideration as the tentative alternatives. Although a large number of mathematical approaches is now available to evaluate, select and rank the alternative materials for a given engineering application, this paper explores the applicability and capability of two almost new MCDM methods, i.e. complex proportional assessment (COPRAS) and evaluation of mixed data (EVAMIX) methods for materials selection. These two methods are used to rank the alternative materials, for which several requirements are considered simultaneously. Two illustrative examples are cited which prove that these two MCDM methods can be effectively applied to solve the real time material selection problems. In each example, a list of all the possible choices from the best to the worst suitable materials is obtained which almost match with the rankings as derived by the past researchers.     

Crack patterns and strain energy distributions in model brittle systems in a random environment

Monte Carlo simulations of crack growth are performed using simple two-dimensional model systems for brittle materials. Crack growth is modelled as a series of processes of release and transfer of strain energies on the system of square grains. The simulations are concerned with crack growth in a random environment. Considerable attention is paid to the correlation between crack patterns and strain energy distributions. It is shown that the model system settles into a stationary state. In this state, the features of crack pattern have a close relation to the characteristics of strain energy distribution. Some implications of the results are discussed in regard to crack patterns caused by heating, radiation, or random mechanical loading on the surface of real brittle materials.     

Equation of state of refractory materials at very high temperatures—theoretical and experimental studies

This paper describes some of the theoretical and experimental studies being carried out at IGCAR on the equation of state of refractory materials like reactor fuels at high temperatures (>3000 K). The equation of state is primarily calculated by the principle of corresponding states. The influence of these equations of state on energy release in a hypothetical core disruptive accident in a fast breeder reactor is indicated. Details of an experimental facility based on laser induced vapourization mass spectrometry, which is being developed to measure the vapour pressures of materials at high temperatures is presented. Possible applications of this facility in other fields of materials research are indicated.     

比较国内外塑料食品包材及溶剂残留管理现状

综述并比较了我国、日本以及韩国3个亚洲国家,以及欧盟、美国、加拿大和澳大利亚等欧美国家对于塑料食品包装材料的管理体系和相关法规;同时,对上述国家和组织对于食品包装材料中溶剂残留限量的规定情况以及标准检测方法,也进行了比较研究.