Advancing glasses through fundamental research

Fundamental research is critical for enabling future breakthroughs in glass science and technology. This is especially true as we approach a new decade of glass research, when addressing technological challenges will require an unprecedented knowledge of structure–property relationships and of the thermodynamics and kinetics of the glassy state. Proper understanding of these issues can be gained only through advances in our knowledge of the physics and chemistry of the glassy state.Recent advances in modeling and simulation have enabled researchers to study glass physics and chemistry at the atomic level. Molecular dynamics and Monte Carlo simulations have proved invaluable for understanding the relationships between glass structure and properties. More recently, a master equation approach has been applied in the energy landscape framework to allow for direct simulation of glass transition range behavior on a laboratory time scale.Furthermore, recent experimental studies have led to a great growth in our understanding of pressure effects in glass. In particular, distinct types of glassy phases can be produced using the same composition but different pressure conditions. This effect, dubbed “polyamorphism,” has provided a new depth to our understanding of the thermodynamics and statistical mechanics of glass.     

物理化学课堂教学方法的探索与实践

物理化学在数学、无机化学、分析化学、有机化学等课程的基础上,进一步系统阐述化学理论,是农业院校中生命科学、食品科学、环境科学等专业本科生的必修专业基础课程。由于该课程理论性强、概念抽象难懂,公式定律相对较多,学生普遍感到比较难学。本文针对该课程的特点和要求,对物理化学的课堂教学方法进行了积极的探索和尝试。     

第23届国际玻璃大会综述

作者对第23届国际玻璃大会进行了简单介绍，通过对大会论文进行归纳和解读，分析了玻璃科学技术的现状和发展方向，并指出了我国玻璃领域发展中存在的问题。     

High-Power Solid-State Lasers: a Laser Glass Perspective

Advances in laser glass compositions and manufacturing have enabled a new class of high-energy/high-power (HEHP), petawatt (PW), and high average power (HAP) laser systems that are being used for fusion energy ignition demonstration, fundamental physics research, and materials processing, respectively. The requirements for these three laser systems are different, necessitating different glasses or groups of glasses. The manufacturing technology is now mature for melting, annealing, fabricating, and finishing of laser glasses for all three applications. The laser glass properties of major importance for HEHP, PW, and HAP applications are briefly reviewed and the compositions and properties of the most widely used commercial laser glasses are summarized. Proposed advances in these three laser systems will require new glasses and new melting methods, which are briefly discussed. The challenges presented by these laser systems will likely dominate the field of laser glass development over the next several decades.     

计量在玻璃生产要素中的价值传递与运用探讨

通过阐述计量在科学技术中发挥基础性的作用,把计量包含的思想、方法、工具、关键概念与玻璃企业技术、管理相联系,体现计量在玻璃企业中的重要作用与价值。充分认识和理解计量、测量的一些关键概念、内容及知识脉络有助于更好地掌握生产要素的内在联系,为企业的产品创新和工艺提升提供思想、方法、工具运用方面的参考。同时例举玻璃生产在计量、测量的计算、图像分析方面的应用案例。     

Glass: The Nanotechnology Connection

Nanoscale science and engineering, or “nanotechnology” as it is commonly known, has been a fundamental component of glass technology for hundreds if not thousands of years. Numerous examples can be found where our understanding of glass at the nanoscale level has proved transformational in the fabrication and application of this material. Among these are band theory, photosensitivity, ligand field theory, glass structure, microcrack theory, amorphous phase separation, controlled crystallization, and surface modification. Modern applications of glass in such diverse fields as energy, medicine, electronics, photonics, and communications are critically dependent on our awareness and appreciation of the intrinsic connections between glass and nanotechnology. Starting at the low end of the nanoscale, we review fundamental aspects of these connections with the intent of drawing attention to their role in both contemporary and future glass science and engineering. We argue that many of the most useful and interesting behaviors of glass are born at the nanoscale, even when we initially do not notice it.     

A New Glassy State of Matter: The Color Glass Condensate

This communication describes a newly reported state of matter: The color glass condensate. Analogies to glass science are made for this nuclear physics discovery.     

Design and Construction of Glass Micromodels for the Study of Moisture Transport in Softwoods

Formulating wood drying models with predictive capabilities is still a challenge. Traditionally, the wood drying process is studied macroscopically, with pore-level physics lumped into effective transport properties. However, microvisual experiments in 2-D transparent porous media (known as micromodels) can improve our understanding of the drying process and add to current theories. Here, we make etched glass micromodels with the pore morphology of softwoods and carry out simple drying experiments, thereby proving the potential of this experimental tool on the wood science field. We develop a procedure to generate the random morphology of softwood with a computer program based on known probability distribution laws. In particular, we generate the tracheid cell microfeatures of a softwood longitudinal-tangential section. The wood morphology is etched onto glass using a photolithographic technique, creating softwood glass micromodels. Good agreement is seen between the morphology of microtome sections and our computer-generated softwood. During wood drying, liquid flow is driven by capillary instabilities. Sudden liquid redistribution, know as a Haines jump, spontaneously drains the liquid contained in cell cavities. Viscous flow occurs mainly through liquid films in partially dry cells.     

防辐射无机玻璃性能研究

核科学技术在国防、医学、工业、农业和科研等领域的应用日益广泛,各种辐射如X射线、γ射线和中子辐射对人体、环境、仪器设备等有很大的危害,并引起国际辐射防护领域的极大关注.透明防辐射玻璃是防辐射材料的重要研究方向之一,本文采用熔融浇注法制备了透明防辐射无机玻璃,对其γ射线和中子辐射的防护能力进行了表征,同时对玻璃透过率、软化点等性能进行了表征.结果显示该防辐射无机玻璃对γ射线和中子辐射具有良好的防护能力,且透过率较高,热稳定性和耐热性能好.由于该防辐射无机玻璃综合性能良好,在辐射防护领域有良好的应用前景.     

Current status of the hydrogenation of coals

The theoretical and experimental studies carried out at the Institute for Fossil Fuels during recent years in the modernization of hydrogenation technologies for coal conversion into a liquid fuel under low hydrogen pressure (10 MPa for bituminous coals and 6 MPa for a number of brown coals) are surveyed. These studies are based on the advances of catalysis science and on the current concepts of the hydrogenation of organic compounds and coal multimer. The capacity and cost efficiency of a coal chemical enterprise in the commercialization of the technology are substantiated.     

第22届国际玻璃大会综述

作者对第22届国际玻璃大会进行了简单介绍,通过分析大会论文研究情况,总结了玻璃科学技术的现状,并指出了玻璃学科的发展趋势。     

A Study of Thermal Cutting of Glass

Thermal stresses due to a hot-air jet impinging on a glass sheet can be used to stably initiate and attract a crack toward the jet axis. Relative motion between the jet and glass sheet then can be used to cut the glass sheet. This paper presents a theoretical and experimental study of this process for straight cuts. The model consists of sequentially coupled thermal and stress analyses for different cutting velocities. The stress field is used to compute stress-intensity factors for different assumed positions of a crack behind the moving air jet. The minimum air temperature for cutting and the stand-off distance of the crack behind the nozzle increase as the cutting velocity increases. The various process and material parameters that control the process-including cutting speed, air temperature, and sheet thickness-are reduced to dimensionless numbers. Theoretical results, presented as a map in the space of these dimensionless numbers, describe the conditions under which cutting is possible. An experimental cutting apparatus has been constructed and used to validate the heat-transfer analyses. Cutting experiments on this apparatus are in good agreement with the model.     

Fracture of Tempered Glass

The fracture of thermally tempered glass is discussed in terms Of both the stored elastic strain energy in the glass due to tempering and the elastic energy release rate Of crack extension, 9. The latter is used to obtain an analytical correlation between the maximum tensile stress and the average particle size at time of fracture. The theoretical predictions are supported by experimental data obtained for various glass thicknesses and temper levels.     

玻璃表面化学增强技术

玻璃的理论强度很高,但由于原料组成、熔化、成形和退火等各工艺过程的影响,玻璃的实际强度比理论值要低很多。采用表面化学增强技术,能够降低玻璃的表面缺陷,提升玻璃的力学强度、表面硬度、耐划伤等性能。玻璃表面化学增强技术有离子交换法、表面化学抛光、脱碱增强法、表面涂层增强、表面微晶化增强技术等方法,通过对上述方法的研究和对比分析,每种方法都有各自相应的特点和应用范围,这些方法拓宽了玻璃表面化学增强技术的研究和发展。     

改善聚合物共混材料界面相容性的研究进展

本文综述了聚合物共混材料界面相容性的概念、理论基础以及改善相容性的方法和增容技术的应用，简要介绍了原住复合材料的发展趋势和正弦脉动流场从物理的角度对共混物起到了增容的作用。     

抓好计量工作为企业生产服务

计量是以保证单位统一、量值准确一致的测量。对计量器具要实行科学管理，遵循计量工作的客观规律，为玻璃企业的稳产、高产奠定良好的基础。     

The Interplay between the Theories of Mode Coupling and of Percolation Transition in Attractive Colloidal Systems

In the recent years a considerable effort has been devoted to foster the understanding of the basic mechanisms underlying the dynamical arrest that is involved in glass forming in supercooled liquids and in the sol-gel transition. The elucidation of the nature of such processes represents one of the most challenging unsolved problems in the field of material science. In this context, two important theories have contributed significantly to the interpretation of these phenomena: the Mode-Coupling theory (MCT) and the Percolation theory (PT). These theories are rooted on the two pillars of statistical physics, universality and scale laws, and their original formulations have been subsequently modified to account for the fundamental concepts of Energy Landscape (EL) and of the universality of the fragile to strong dynamical crossover (FSC). In this review, we discuss experimental and theoretical results, including Molecular Dynamics (MD) simulations, reported in the literature for colloidal and polymer systems displaying both glass and sol-gel transitions. Special focus is dedicated to the analysis of the interferences between these transitions and on the possible interplay between MCT and PT. By reviewing recent theoretical developments, we show that such interplay between sol-gel and glass transitions may be interpreted in terms of the extended F13 MCT model that describes these processes based on the presence of a glass-glass transition line terminating in an A3 cusp-like singularity (near which the logarithmic decay of the density correlator is observed). This transition line originates from the presence of two different amorphous structures, one generated by the inter-particle attraction and the other by the pure repulsion characteristic of hard spheres. We show here, combining literature results with some new results, that such a situation can be generated, and therefore experimentally studied, by considering colloidal-like particles interacting via a hard core plus an attractive square well potential. In the final part of this review, scaling laws associated both to MCT and PT are applied to describe, by means of these two theories, the specific viscoelastic properties of some systems.     

真空玻璃封接技术的研究现状及发展

真空玻璃凭借保温隔热、降声降噪、轻薄以及抗结露等优异性能逐步应用于节能建筑、家用电器、交通、农业等领域。尤其在节能建筑领域,真空玻璃展现出广阔的发展前景。通过总结近年来的文献资料,本文回顾了真空玻璃的发展历史,系统介绍了真空玻璃研究基础和产业化技术取得的重大突破及产业化现状,重点描述了真空玻璃封接材料种类、真空玻璃封接技术研究进程及最新研究进展。最后,本文展望了真空玻璃封接材料和封接技术未来发展趋势,以期为高性能真空玻璃的基础研究和产业化应用提供一定的借鉴和参考。     

Submerged Combustion Melting of Glass

Advances in tank melter, refractory, controls, and heat source technology have paralleled progress in glass chemistry, quality, and production scale for decades. These same advances have also led to a revival of the 75-year-old concept of bottom heating for glass melting. To create high-intensity heat transfer and rapid melt homogenization, bottom heating, or submerged combustion melting, uses forced convection and direct contact heat transfer. The work of European, American, and Ukranian scientists has demonstrated that bottom heating offers energy savings, emissions reductions, and cost savings relative to conventional melting. Recent work by the Gas Technology Institute of the United States, in partnership with a consortium of glass companies, has advanced the bottom heating technology for a number of glass products to the brink of commercialization. With ongoing work a practical, rapid refining process could be developed to enable bottom melting as an alternative melting approach for a broad range of commercial glasses.