976 resultados para Sio2


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采用多元统计方法对四川、重庆、贵州、广西、广东地区出土的100余个古玻璃样品的化学成分数据进行了分析处理。结果表明:中国南方和西南地区的古玻璃制品主要由具有中国特色的铅钡硅酸盐玻璃和钾硅酸盐玻璃组成,可细分为五大系统类别:K2O-CaO(~10wt%)-SiO2系统、K2O-SiO2系统、PbO-BaO-SiO2系统、PbO(~25wt%)-BaO-SiO2系统、CaO-PbO(~40wt%)-BaO—SiO2系统。用因子分析探讨了我国汉代南方和西南地区的玻璃本地生产情况,表明该地区在汉代已经拥有自主生产

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对化学成分体系的确定是中国古代玻璃研究中很重要的一个方面,为此,用外束质子激发X荧光技术(PIXE)、电感耦合等离子体原子发射光谱分析(ICP-AES)等方法,对新疆、湖北、河南和重庆等地区出土的一批战国时期的玻璃珠(包含镶嵌玻璃珠)、玻璃璧样品进行了检测。结果表明,战国时期中国境内同时存在PbO-BaO-siO2、K2O-SiO2、Na2O-CaO-SiO2三种硅酸盐玻璃,分布的地域范围从中国的新疆东部一直到长江、黄河流域,以及南方的四川、贵州等地区。中国古代的PbO-BaO-SiO2和K2O-SiO玻

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Si:SbOx films have been deposited by reactive dc-magnetron sputtering from a Sb target with Si chips attached in Ar + O-2 with the relative O-2 content 7%. The as-deposited films contained Sb metal, Sb2O3, SiO, Si2O3 and SiO2. The crystallization of Sb was responsible for the changes of optical properties of the films. The results of the blue laser recording test showed that the films had good writing sensitivity for blue laser beam (406.7 nm), and the recording marks were still clear even if the films were deposited in air 60 days, which demonstrated that doping silicon in SbOx films can improve the stability of SbOx films. High reflectivity contrast of about 36% was obtained at a writing power 6 mW and writing pulse width 300 ns. (c) 2007 Elsevier B.V. All rights reserved.

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采用改进的外束质子激发x射线荧光、电感耦合等离子体原子发射光谱分析等技术,对广西合浦地区出土的一批汉代古玻璃样品的化学成分和结构特性等进行了检测。结果表明:两汉时期,合浦地区的古代玻璃存在K2O—SiO2、PbO-BaO-SiO2、PbO—SiO2、Na2O-K2O-PbO-SiO2、(Na2O)K2O-CaO—SiO2等多种类型,但绝大多数为K2O—SiO2玻璃。表面风化可引起K2O-SiO2玻璃表面K2O等助熔剂的流失和富硅层的形成。综合化学成分以及器型特征,认为我国汉代K2O—SiO2玻璃制造技术可

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Cylindrical vector beams were produced from laser diode end-pumped Nd:YAG ceramic microchip laser by use of two types of subwavelength multilayer gratings as the axisymmetric-polarization output couplers respectively. The grating mirrors are composed of high- and low-refractive-index (Nb2O5/SiO2) layers alternately while each layer is shaped into triangle and concentric corrugations. For radially polarized laser output, the beam power reached 610mW with a polarization extinction ratio ( PER) of 61: 1 and a slope efficiency of 68.2%; for azimuthally polarized laser output, the beam power reached 626mW with a PER of 58: 1 and a slope efficiency of 47.6%. In both cases, the laser beams had near-diffraction limited quality. Small differences of beam power, PER and slope efficiency between radially and azimuthally polarized laser outputs were not critical, and could be minimized by further optimized adjustment to laser cavity and the reflectances of respective grating mirrors. The results manifested, by use of the photonic crystal gratings mirrors and end-pumped microchip laser configuration, CVBs can be generated efficiently with high modal symmetry and polarization purity. (C) 2008 Optical Society of America.

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稀土离子掺杂的氧氟玻璃是一种新型上转换发光材料。制备了Tm^3/Yb^3+单掺、共掺的摩尔分数为n(SiO2)-0.30,n(PbF2)-0.50,n=(Al2O3)=0.15,n(AlF3)=(0.049-x),n(TmF3)=y,n(YbF3)=x(x=0,0.001,0.010,0.015,0.020,y=0,0.001)系统氧氟玻璃,研究了其上转换发光特性、分析了其上转换发光机理。研究发现,在970nm抽运光源激发下,Tm^3+单掺时没有可见光上转换发射;而加入Yb^3+后产生了强的蓝光(452n

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Transparent Ni2+-doped MgO-Al2O3-TiO2-SiO2 glass ceramics were prepared, and the optical properties of Ni2+-doped glass ceramics were investigated. Broadband emission centered at 1320 nm was observed by 980 nm excitation. The longer wavelength luminescence compared with Ni2+-doped Li2O-Ga2O3-SiO2 glass ceramics is ascribed to the low crystal field hold by Ni2+ in MgO-Al2O3-TiO2-SiO2 glass ceramics. The change in optical signals at the telecommunication bands with or without 980 nm excitation was also measured when the seed beam passes through the bulk gain host.(C) 2007 American Institute of Physics.

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采用传统的玻璃熔融方法,研究了Bi2O3-B2O3-TiO2-RmOn四元系统的玻璃形成区(RmOn分别为La2O3、Sb2O3、ZrO2、SiO2和Nb2O5氧化物),给出了上述四元系统的玻璃形成范围。研究发现:Bi2O3-B2O3-TiO2-La2O3系统的玻璃形成范围最大,当TiO2的摩尔含量超过25%时,上述五个系统均不能形成玻璃。分剐熔制了摩尔分数55Bi2O3-35B2O3—5TiO2—5RmOn的玻璃(RmOn分别为La2O3、Sb2O3、ZrO2、SiO2和Nb2O5),测定了其红外吸收光

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:为提高大功率脉冲氙灯的封接强度,将微晶玻璃作为封接材料引入到氙灯封接应用中. 以 Bi2O3,ZnO,Al2O3,MgO,CaCO3,SiO2,BaO,H3BO3,P2O5,Na2O 为原料,通过高温熔融制备了大功率脉冲氙灯封接 用微晶玻璃样品. 测试了样品的热膨胀系数,并通过差热分析(Differential Thermal Analysis,DTA)对脉冲氙灯 微晶玻璃的封接温度进行了讨论,用X 射线衍射(X-ray diffraction ,XRD)表征了封接玻璃,并进行了分析. 将 制得的样品磨成玻璃粉末,制成膏剂状玻璃焊料,对大功率脉冲氙灯进行封接,得到大功率脉冲氙灯的微晶 玻璃封接件. 通过氦质谱检漏仪检测,1#、2#、4#封接件气密性良好,达到10-6 Pa.

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A series of binary borosilicate glasses prepared by the sol-gel method are shown to be bioactive. Tetraethyl orthosilicate (TEOS) and trimethylborate (TMB) in acidic medium are used to prepare xB(2)O(3)center dot(1-x)SiO2 glass systems for x = 0.045-0.167. The formation of a layer of apatite-like mineral on the glass surface becomes apparent after soaking in simulated body fluid for 48 h. We have measured the B-11-B-11 homonuclear second moments of the borosilicate glasses and inferred that no macroscopic phase separation occurred in our glasses. The B-11 chemical shift data also show that the formation of clustered boroxol rings is negligible in our glass system. Although the bioactivity of our borosilicate glasses is less than that of CaO-SiO2 sol-gel glasses, these simple binary systems could be taken as reference glass systems for the search of new bioactive borosilicate glasses. (C) 2008 Elsevier Ltd. All rights reserved.

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The emission intensity of Ni2+ at 1200 nm in transparent ZnO-Al2O3-SiO2 glass ceramics containing ZnAl2O4 nanocrystals is improved approximately 8 times by Cr3+ codoping with 532 nm excitation. This enhanced emission could be attributed to an efficient energy transfer from Cr3+ to Ni2+, which is confirmed by time-resolved emission spectra. The energy transfer efficiency is estimated to be 57% and the energy transfer mechanism is also discussed. (C) 2008 Optical Society of America.

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The near-infrared emission intensity of Ni2+ in Yb3+/Ni2+ codoped transparent MgO-Al2O3-Ga2O3-SiO2-TiO2 glass ceramics could be enhanced up to 4.4 times via energy transfer from Yb3+ to Ni2+ in nanocrystals. The best Yb2O3 concentration was about 1.00 mol%. For the Yb3+/Ni2+ codoped glass ceramic with 1.00 mol% Yb2O3, a broadband near-infrared emission centered at 1265 nm with full width at half maximum of about 300 nm and lifetime of about 220 mu s was observed. The energy transfer mechanism was also discussed. (C) 2008 Optical Society of America.