نتایج جستجو برای: glasses
تعداد نتایج: 14679 فیلتر نتایج به سال:
Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the source is credited. DOI 10.3109/17453674.2014.893499 A problem commonly encountered by all surgical staff in theaters is the slipping of glasses down the bridge of the nose, especially du...
The deformation of metallic glasses involves two competing processes: a disordering process involving dilatation, free volume accumulation, and softening, and a relaxation process involving diffusional ordering and densification. For metallic glasses at room temperature and under uniaxial loading, disordering usually dominates, and the glass can fail catastrophically as the softening process ru...
In this talk I will show that usual spin glasses are a peculiar kind of Abelian gauge theory. I will shortly review the techniques used to study them. At the end I will consider more general models (e.g. spin glasses based on non Abelian gauge group) and I will discuss the relevance of these models to real glasses. Finally I will derive from first principles a generalised Vogel-Fulcher law for ...
تهیه، مشخصهیابی و ارزیابی مقایسهای زیست فعالی سه نوع نانو پودر شیشه زیست فعال برای کاربردهای پزشکی
Fabrication of biomaterials with ability to form a bond with bone tissue for bone skeletal system repair is one of the biomaterial science aims. Bioactive glasses containing CaO-SiO2-P2O5 are among the most important groups used in biomedicine and dentistry such as bone defect repair and maxillo-facial reconstruction. The aim of this work was preparation and characterization of nano particle b...
The infrared spectra of xPbO (1−x−z)SiO2zP2O5 glasses with a PbO:SiO2 molar ratio of 3:2 and z=0,1,2,5,30,40 and 50 mol% have been examined in the region 4000-400 cm, together with XRD. The structure of PbO-SiO2 binary glass is significantly different from that of P2O5 substituted glasses. The low amount of P2O5 containing PbO-SiO2 glasses results in infrared spectra of the same pattern as 3:2 ...
purpose: the impact of photo refractive keratectomy compared with using glasses or contact lens on patient’s quality of life (qol) in myopia. method: in this retrospective cohort study, 102 myopic patient who had undergone prk (at least 6 months ago) and 106 myopic patients using glasses or contact lens were included. changes in vision related qol, uncorrected and best corrected visual acuity (...
This paper is an introduction to some of the main present issues in the theory of structural glasses. After recalling a few experimental facts, it gives a short account of the analogy between fragile glasses and the mean field discontinuous spin glasses. The many valley picture is presented, and a brief account of recent attempts to obtain quantitative results from first principle computations ...
Owing to similarity in both ionic size and polarity, strontium (Sr2+) is known to behave in a comparable way to calcium (Ca2+), and its role in bone metabolism has been well documented as both anti-resorptive and bone forming. In this study, novel quaternary strontium-doped phosphate-based glasses, containing 1, 3 and 5 mol% SrO, were synthesized and characterized. (31)P magic angle spinning (M...
Technetium-99 (Tc) and iodine-129 (I) are two long-lived fission products of high volatility, which makes their study in glass structure challenging. Both technetium and iodine have broad ranging multivalent chemistry and complex reactivity dependent on redox conditions; technetium and iodine redox may vary from Tc to Tc and from I to I. Relatively few studies have been done on their speciation...
Rare-earth co-doping in inorganic materials has a long-held tradition of facilitating highly desirable optoelectronic properties for their application to the laser industry. This study concentrates specifically on rare-earth phosphate glasses, (R2O3)x(R'2O3)y(P2O5)(1-(x+y)), where (R, R') denotes (Ce, Er) or (La, Nd) co-doping and the total rare-earth composition corresponds to a range between ...
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