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141.
Research on the properties and characteristics of glass that determine the serviceability of the most massive glass objects and glassware is reviewed. The theoretical assumptions, general questions concerning the strength, chemical resistance (corrosion), and spectral characteristics of glass are noted. The properties and characteristics indicated are examined for sheet glass, glass fiber, and glassware.  相似文献   
142.
It is generally accepted that diamond is resistant to a wide spectrum of electromagnetic radiation from the ultraviolet through to the soft X-ray range, which makes it very attractive for the fabrication of diamond-based photodetectors. However the effect of photon radiation on the diamond structure has not yet been examined. In the work presented here, photoelectron spectroscopy has been used to study the graphitization of nanodiamond crystallites exposed to extreme ultraviolet radiation. Under such irradiation, the surface hydrogen groups and graphite species are found to prevent graphitization. The mechanism of radiation-induced nanodiamond graphitization is discussed.  相似文献   
143.
We present a numerical study of the packing of uniform spheres under three-dimensional vibration using the discrete element method (DEM), focusing on the effects of vibration condition (amplitude and frequency) and inter-particle frictions (sliding and rolling frictions). The results are analysed in terms of packing density, coordination number (CN), radial distribution function (RDF) and pore structure. It is shown that increasing either the vibration amplitude or frequency causes packing density to increase initially to a maximum and then decrease. Both vibration frequency and amplitude should be considered to characterize the effect of vibration process on packing structure. The sliding and rolling frictions between particles can decrease packing density since they dissipate energy, although the effect of rolling friction is less significant. In line with the change of packing density, microstructural properties such as CN, RDF and pore distribution also change: a looser packing often corresponds to smaller CN, less peaked RDF and larger but more widely distributed pores.  相似文献   
144.
Ring‐opening polymerization of D,L ‐lactide (LA) has been successfully carried out by using rare earth 2,6‐dimethylaryloxide (Ln(ODMP)3) as single component catalyst or initiator for the first time. The effects of different rare earth elements, solvents, monomers and catalyst concentration as well as polymerization temperature and time on the polymerization were investigated. The results show that La(ODMP)3 exhibits higher activity to prepare poly(D,L ‐lactide) (PLA) with a viscosity molecular weight of 4.5 × 104 g mol?1 and the conversion of 97 % at 100 °C in 45 min. The catalytic activity of Ln(ODMP)3 has following sequence: La > Nd > Sm > Gd > Er > Y. A kinetic study has indicated that the polymerization is first order with respect to both monomer and catalyst concentration. The apparent activation energy of the polymerization of LA with La(ODMP)3 is 69.6 kJ mol?1. The analyses of polymer ends indicate that the LA polymerization proceeds according to ‘coordination–insertion’ mechanism with selective cleavage of the acyl–oxygen bond of the monomer. Copyright © 2004 Society of Chemical Industry  相似文献   
145.
A diagnostic array has been developed for studying the operating modes of the divertor in the ITER tokamak-reactor using the Thomson scattering technique. The aim of this study is to measure the spatial profiles of the electron temperature and density. The structure of the diagnostic setup was selected on the basis of a classical diagnostic geometry and the high-resolution LIDAR system, which provide access to different regions of the divertor plasma. A severe radiation environment, limited access to the plasma in the ITER divertor, and a high-dust environment (the divertor plate erosion material) in the divertor volume pose many problems for performing diagnostics under unique conditions having no analogs in the tokamaks that are now in operation. Different methods for protecting optical surfaces from plasma-enriched deposition are proposed and analyzed. The efficiency of these methods has been demonstrated in bench tests. The concept of laser and detector systems and diffraction polychromators capable of operating at different electron temperatures with a lower limit of 1 eV, has been justified and approved.  相似文献   
146.
147.
The results from a study of an arc plasma source with a cold hollow cathode are presented. The source generates plasma with a density of ∼1010 cm−3 in a volume of ∼0.2 m3 at discharge currents of up to 150 A, an arc discharge operating voltage of 30–40 V, and a low pressure of 0.1–1 Pa. The motion of the cathode spot in the crossed electric and magnetic fields inside the hollow cathode and the cathode’s special design make it possible to eliminate almost completely the penetration of the sputtered cathode material into the working vacuum chamber.__________Translated from Pribory i Tekhnika Eksperimenta, No. 3, 2005, pp. 62–66.Original Russian Text Copyright © 2005 by Schanin, Koval, Akhmadeev.  相似文献   
148.
The radioecological conditions which developed on the territory over the long operating time of the object of the naval fleet in Guba Andreev are described. The results of an analysis of the sources of the real and potential danger and measures to prevent dangerous effects for the environment and the workers at the time remediation work is performed are discussed. __________ Translated from Atomnaya énergiya, Vol. 101, No. 1, pp. 49–55, July, 2006.  相似文献   
149.
中国古陶艺制品造型,釉色,装饰等艺术符号都与每时期的阶段性精神和物质生活相联系,但在"现代艺术"文化认识领域中,往往从理论思维角度把陶艺实用目的的物质性排斥在文化范畴之外。艺术常常强调物质的观赏性,而陶艺的实用功能就是这种文化类型的主体,陶艺的文化性和功能性,具有实用和审美文化的高度叠合,永久地承载着实用功能和精神功能两大内容。  相似文献   
150.
Abstract— An all solid‐state photoelectrochromic element (PECE) was developed on the basis of electrochromic layers of WO3 and polyaniline with a layer of polymer electrolyte placed on a base of polyamidosulfoacid, in which a thin‐film CdSxSe1?x photoresistor was used as an electronic key. The dependence of the sensitometric characteristics of the PECE on the applied voltage was studied.  相似文献   
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