Xem 1-20 trên 27 kết quả Polymer solids
  • Introduction: Other than in solutions or in ionic liquids, ionic conduction can take place in the solid state also. The solids that exhibit ionic conduction are called ‘solid-state ionic conductors’. Based on the charge of ionic species responsible for the conduction, they are divided into cationic and anionic conductors; then, based on specific species involved in the conduction, they are further subdivided into sodium ion conductors, proton conductors, fluorine ion conductors, and so on.

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  • Synthetic polymers are essential for modern human life, since they are used in industrial and agricultural fields. However, most synthetic polymers that have been developed by using petroleum and coal as raw materials are not compatible with the environment, since they cannot be included in the natural recycling system. There are serious contradictions between the convenience that people require today and compatibility with the natural environment. It is easy to say that we should use only natural materials in order to solve the problems coming from man-made materials.

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  • The general review of influence of the pollutants on polymers has been presented by Jellinek et al. [1]. Therein the characterization of reactivity of polymeric materials toward aggressive gases is given. The various polymers were used as films of 20 μ thickness. The thickness is enough small to exclude in most cases the diffusion as the determining factor of the pollutant action. The films were investigated under different conditions: 1) the pollutant action; 2) the oxygen action; 3) UV light action; 4) UV light and oxygen; 5) UV light, oxygen and pollutants.

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  • Document "Mechanical properties of solid polymer" presentation of content: Ideal Solids, tensile properties, shear properties, compressive properties, hardness, impact strength, coefficient of friction.

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  • Innovation in engineering often means the clever use of a new material - new to a particular application, but not necessarily (although sometimes) new in the sense of ‘recently developed’. Plastic paper clips and ceramic turbine-blades both represent attempts to do better with polymers and ceramics what had previously been done well with metals. And engineering disasters are frequently caused by the misuse of materials.

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  • Metals are used as biomaterials due to their excellent electrical and thermal conductivity and mechanical properties. Since some electrons are independent in metals, they can quickly transfer an electric charge and thermal energy. The mobile free electrons act as the binding force to hold the positive metal ions together. This attraction is strong, as evidenced by the closely packed atomic arrangement resulting in high specific gravity and high melting points of most metals.

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  • Introduction: The electrolyte solution is a major component of all battery systems and as such will greatly influence energy densities (thermodynamic properties such as Gibbs energy, enthalpy, and ionic activity) and power densities (nonthermodynamic properties such as viscosity, conductivity, and transference). The electrolyte solution consists of a liquid or solid phase containing at least one component, e.g., water, which is called the solvent, and an ionizable substance, e.g., a salt or an acid, which is called the electrolyte. ...

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  • In the next block processing features to detect a particular event in the case external devices, or to identify, study, and signal the brain to recognize patterns, will be used as input for the following blocks that translate to control command of the external device. Last but not least important, is the block set effects supervision Operative mode of BCI devices under the supervision of users, this is if the device is active in on-line / Off linemode, or if it ismodifying its internal parameters in the learning phase in order to regulate the activity of users....

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  • Analysis was conducted on all nutrients or nutrient groups for which numeric data were provided in at least 10 of the 137 crop studies that reported comparisons between organic and conventional crops (see Appendix 10).

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  • Today there is not a single aspect of the world that can escape the scrutiny of environmental analysis, and business activities stand at the crux of many issues. Some of the issues that today’s executives need to understand to be environmentally literate include: air, water, and land pollution; the production and disposal of hazardous wastes; solid waste disposal; chemical and nuclear spills and accidents; global warming and the greenhouse effect; ozone depletion; deforestation and desertification; biodiversity, and overpopulation.

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  • Pulp and paper is a mature industry. Industrialised paper manufacturing in Europe started in the early 19th century (Berkhout, 2005). It is a capital and resource-intensive industry that contributes to many environmental problems, including global warming, human tox- icity, eco-toxicity, photochemical oxidation, acidification, nutrification, and solid wastes (Blazejczak and Edler, 2000). Paper is made of natural fibres, either from wood or from recycled materials. Figure 1 below presents a schematic representation of the production system.

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  • Conventional electrostatic capacitors contain a dielectric instead of an electrolyte solution. Electrochemical supercapacitors, however, contain a liquid electrolyte (aqueous, nonaqueous), and can be classified by the electrode material used (carbon, metal oxide, polymer) and the operating principle (double-layer capacitance, redox pseudocapacitance, hybrid capacitance).

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  • The state-of-the-art of controlled radical polymerization (CRP) in 2011 is presented. Atom transfer radical polymerization, stable radical mediated polymerization, and degenerate transfer processes, including reversible addition fragmentation chain transfer are the most often used CRP procedures. CRP opens new avenues to novel materials from a large range of monomers. Detailed structure-reactivity relationships and mechanistic understanding not only helps attain a better controlled polymerization but enables preparation of polymers with complex architectures.

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  • Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Polystyrene-Al2O3 composite solid polymer electrolyte for lithium secondary battery

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  • Effects of Structure on Properties Physical properties of metals, ceramics, and polymers, such as ductility, thermal expansion, heat capacity, elastic modulus, electrical conductivity, and dielectric and magnetic properties, are a direct result of the structure and bonding of the atoms and ions in the

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  • The stereolithographic (SL) process is performed on the equipment shown in Figure 1. The movable platform on which the 3D model is formed is initially immersed in a vat of liquid photopolymer resin to a level just below its surface so that a thin layer of the resin covers it. The SL equipment is located in a sealed chamber to prevent the escape of fumes from the resin vat. The resin changes from a liquid to a solid when exposed to the ultra- violet (UV) light from a low-power, highly focused laser.

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  • This book is dedicated to thermoset resins, an important class of polymer materials. Unlike thermoplastics, thermoset resins are characterised by a curing reaction, which converts the low molecular weight liquid resins (easy to process) into solid three- dimensional network structures. The main advantage of a thermoset over a thermoplastic is that a wide range of properties can be achieved by simply adjusting the crosslink density of the thermoset network...

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  • One of the greatest challenges faced by the food scientist is man himself with his highly sensitive oral equipment for evaluating food texture. The recognition of this challenge leads immediately to two questions: ‘How can we characterize the texture of foodstuffs in a manner that will reflect human perceptions?’ and, then, ‘How may we preserve, formulate and process products in a way that will be acceptable to the consumer?’

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  • Introduction: Background The vast majority of research into solid-state polymer electrolytes for low-temperature (o200 1C) fuel cells has focused on proton-exchange membrane (PEM) fuel cells (PEMFCs). Recently, there has been interest in the application of the analogous anion-exchange membranes (AEMs), in alkaline forms, in low-temperature fuel cells (Figure 1).

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  • PART 1 MATERIALS AND MECHANICAL DESIGN CHAPTER 1 STRUCTURE OF SOLIDS Charles H. Drummond III Department of Materials Science and Engineering Ohio State University Columbus, Ohio 1.1 INTRODUCTION 1.1.1 Effects of Structure on Properties 1. .2 Atomic Structure 1. .3 Bonding 1. .4 Simple Structures 1. .5 Crystallography 1. .6 States of Matter 1. .7 Polymorphism 1. .8 Defects 1.2 METALS 1.2.1 Structures 3 3 3 4 4 5 7 8 8 12 12 1.2.2 1.2.3 Alloys Noncrystalline Metals 13 13 14 14 14 15 15 15 15 15 1.3 CERAMICS 1.3.1 Crystalline Ceramics 1.3.2 Noncrystalline Ceramics 1.3.

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