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Sample records for sapphire natural quartz

  1. Erbium-doped crystalline YAG planar and ridge waveguides on quartz and sapphire substrates: deposition and material characterisation

    Science.gov (United States)

    Facchini, G.; Zappettini, A.; Canali, A.; Martinelli, M.; Gabetta, G.; Tallarida, G.

    2001-06-01

    Er-doped Yttrium-Aluminium-Garnet (YAG) planar and ridge waveguides have been grown on quartz and sapphire substrates. The waveguides have been structurally, morphologically and stoichiometrically characterised by X-ray diffraction, atomic force microscopy and X-ray photoelectron spectroscopy. Doping concentrations up to 5% have been successfully demonstrated. Deposition of channel waveguide on sapphire substrate results in a correct ridge shape.

  2. Detection of beryllium treatment of natural sapphires by NRA

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, P.C., E-mail: carolina.gutierrez@uam.e [Centro de Micro-Analisis de Materiales (CMAM), Universidad Autonoma de Madrid, Campus de Cantoblanco, 28049 Madrid (Spain); Ynsa, M.-D.; Climent-Font, A. [Centro de Micro-Analisis de Materiales (CMAM), Universidad Autonoma de Madrid, Campus de Cantoblanco, 28049 Madrid (Spain); Dpto. Fisica Aplicada C-12, Universidad Autonoma de Madrid, Campus de Cantoblanco, 28049 Madrid (Spain); Calligaro, T. [Centre de Recherche et de Restauration des musees de France C2RMF, CNRS-UMR171, 14 quai Francois Mitterrand, 75001 Paris (France)

    2010-06-15

    Since the 1990's, artificial treatment of natural sapphires (Al{sub 2}O{sub 3} crystals coloured by impurities) by diffusion of beryllium at high temperature has become a growing practice. This process permits to enhance the colour of these gemstones, and thus to increase their value. Detection of such a treatment - diffusion of tens of {mu}g/g of beryllium in Al{sub 2}O{sub 3} crystals - is usually achieved using high sensitivity techniques like laser-ablation inductively coupled plasma mass spectrometry (LA-ICP/MS) or laser-induced breakdown spectrometry (LIBS) which are unfortunately micro-destructive (leaving 50-100-{mu}m diameter craters on the gems). The simple and non-destructive alternative method proposed in this work is based on the nuclear reaction {sup 9}Be({alpha}, n{gamma}){sup 12}C with an external helium ion beam impinging on the gem directly placed in air. The 4439 keV prompt {gamma}-ray tagging Be atoms are detected with a high efficiency bismuth germanate scintillator. Beam dose is monitored using the 2235 keV prompt {gamma}-ray produced during irradiation by the aluminium of the sapphire matrix through the {sup 27}Al({alpha}, p{gamma}){sup 30}Si nuclear reaction. The method is tested on a series of Be-treated sapphires previously analyzed by LA-ICP/MS to determine the optimal conditions to obtain a peak to background appropriate to reach the required {mu}g/g sensitivity. Using a 2.8-MeV external He beam and a beam dose of 200 {mu}C, beryllium concentrations from 5 to 16 {mu}g/g have been measured in the samples, with a detection limit of 1 {mu}g/g.

  3. Detection of beryllium treatment of natural sapphires by NRA

    Science.gov (United States)

    Gutiérrez, P. C.; Ynsa, M.-D.; Climent-Font, A.; Calligaro, T.

    2010-06-01

    Since the 1990's, artificial treatment of natural sapphires (Al 2O 3 crystals coloured by impurities) by diffusion of beryllium at high temperature has become a growing practice. This process permits to enhance the colour of these gemstones, and thus to increase their value. Detection of such a treatment - diffusion of tens of μg/g of beryllium in Al 2O 3 crystals - is usually achieved using high sensitivity techniques like laser-ablation inductively coupled plasma mass spectrometry (LA-ICP/MS) or laser-induced breakdown spectrometry (LIBS) which are unfortunately micro-destructive (leaving 50-100-μm diameter craters on the gems). The simple and non-destructive alternative method proposed in this work is based on the nuclear reaction 9Be(α, nγ) 12C with an external helium ion beam impinging on the gem directly placed in air. The 4439 keV prompt γ-ray tagging Be atoms are detected with a high efficiency bismuth germanate scintillator. Beam dose is monitored using the 2235 keV prompt γ-ray produced during irradiation by the aluminium of the sapphire matrix through the 27Al(α, pγ) 30Si nuclear reaction. The method is tested on a series of Be-treated sapphires previously analyzed by LA-ICP/MS to determine the optimal conditions to obtain a peak to background appropriate to reach the required μg/g sensitivity. Using a 2.8-MeV external He beam and a beam dose of 200 μC, beryllium concentrations from 5 to 16 μg/g have been measured in the samples, with a detection limit of 1 μg/g.

  4. Dosimetric properties of natural quartz grains extracted from fired materials

    DEFF Research Database (Denmark)

    Bluszcz, A.; Bøtter-Jensen, L.

    1995-01-01

    The paper describes an examination of the dosimetric properties of natural quartz grains extracted from ancient fired materials. Eleven samples of different origin were tested for their TL and GLSL (green light stimulated luminescence) sensitivities within the mGy dose range. Very promising results...... were obtained showing the possibility of measuring the doses of around 10 mGy with 1% precision using GLSL or TL and using the single aliquot technique for natural quartz as a dosimeter. The lowest detectable dose was estimated to be lower than 500 mu Gy. The results obtained indicate that natural...... quartz grains from selected materials could be used for the dosimetry of environmental gamma radiation for the purposes of paleodosimetric dating methods as well as for accident dosimetry....

  5. Evidence for residual elastic strain in deformed natural quartz

    Energy Technology Data Exchange (ETDEWEB)

    Kunz, Martin; Chen, Kai; Tamura,Nobumichi; Wenk, Hans-Rudolf

    2009-01-30

    Residual elastic strain in naturally deformed, quartz-containing rocks can be measured quantitatively in a petrographic thin section with high spatial resolution using Laue microdiffraction with white synchrotron x-rays. The measurements with a resolution of one micrometer allow the quantitative determination of the deviatoric strain tensor as a function of position within the crystal investigated. The observed equivalent strain values of 800-1200 microstrains represent a lower bound of the actual preserved residual strain in the rock, since the stress component perpendicular to the cut sample surface plane is released. The measured equivalent strain translates into an equivalent stress in the order of {approx} 50 MPa.

  6. Carbothermal Reduction of Quartz with Carbon from Natural Gas

    Science.gov (United States)

    Li, Fei; Tangstad, Merete

    2017-04-01

    Carbothermal reaction between quartz and two different carbons originating from natural gas were investigated in this paper. One of two carbons is the commercial carbon black produced from natural gas in a medium thermal production process. The other carbon is obtained from natural gas cracking at 1273 K (1000 °C) deposited directly on the quartz pellet. At the 1923 K (1650 °C) and CO atmosphere, the impact of carbon content, pellet structure, gas transfer, and heating rate are investigated in a thermo-gravimetric furnace. The reaction process can be divided into two steps: an initial SiC-producing step followed by a SiO-producing step. Higher carbon content and increased gas transfer improves the reaction rate of SiC-producing step, while the thicker carbon coating in carbon-deposited pellet hinders reaction rate. Better gas transfer of sample holder improves reaction rate but causes more SiO loss. Heating rate has almost no influence on reaction. Mass balance analysis shows that mole ratios between SiO2, free carbon, and SiC in the SiC-producing step and SiO-producing step in CO and Ar fit the reaction SiO2(s) + 3 C(s) = SiC(s) + 2 CO(g). SiC-particle and SiC-coating formation process in mixed pellet and carbon-deposited pellet are proposed. SiC whiskers formed in the voids of these two types of pellets.

  7. Carbothermal Reduction of Quartz with Carbon from Natural Gas

    Science.gov (United States)

    Li, Fei; Tangstad, Merete

    2017-01-01

    Carbothermal reaction between quartz and two different carbons originating from natural gas were investigated in this paper. One of two carbons is the commercial carbon black produced from natural gas in a medium thermal production process. The other carbon is obtained from natural gas cracking at 1273 K (1000 °C) deposited directly on the quartz pellet. At the 1923 K (1650 °C) and CO atmosphere, the impact of carbon content, pellet structure, gas transfer, and heating rate are investigated in a thermo-gravimetric furnace. The reaction process can be divided into two steps: an initial SiC-producing step followed by a SiO-producing step. Higher carbon content and increased gas transfer improves the reaction rate of SiC-producing step, while the thicker carbon coating in carbon-deposited pellet hinders reaction rate. Better gas transfer of sample holder improves reaction rate but causes more SiO loss. Heating rate has almost no influence on reaction. Mass balance analysis shows that mole ratios between SiO2, free carbon, and SiC in the SiC-producing step and SiO-producing step in CO and Ar fit the reaction SiO2(s) + 3 C(s) = SiC(s) + 2 CO(g). SiC-particle and SiC-coating formation process in mixed pellet and carbon-deposited pellet are proposed. SiC whiskers formed in the voids of these two types of pellets.

  8. Synergetic Surface and Chemical Durability Study of the Aesthetically Enhanced Natural Quartz by Heat Treatment

    Science.gov (United States)

    Sahoo, Rakesh K.; Rout, Prajna P.; Singh, Saroj K.; Mishra, Barada K.; Mohapatra, Birendra K.

    2017-03-01

    The change in surface behavior of natural quartz stone before and after heat treatment with metal oxides such as: cobalt oxide (Co3O4) and copper oxide (Cu2O) under vacuum and open atmosphere has been investigated. The surface feature, bulk density and hardness value of quartz changed after heat treatment, converting to a high value product. Difference in crystallinity of quartz, pre- and post-heat treatment was obtained through X-ray diffraction (XRD) study. The electron probe microanalysis results clearly explicated the diffusion of metal ion in quartz matrix exposed under vacuum atmosphere but as coating on the surface under open atmosphere. The structural transformation of quartz after heat treatment has been observed from the XRD data and well corroborated with the nanoindentation results. Durability of such quartz to chemical hazardous environment was observed. Thus, this communication demonstrates the change in physical and chemical characteristics of natural quartz stone after heat treatment under different atmosphere.

  9. Synergetic Surface and Chemical Durability Study of the Aesthetically Enhanced Natural Quartz by Heat Treatment

    Science.gov (United States)

    Sahoo, Rakesh K.; Rout, Prajna P.; Singh, Saroj K.; Mishra, Barada K.; Mohapatra, Birendra K.

    2017-01-01

    The change in surface behavior of natural quartz stone before and after heat treatment with metal oxides such as: cobalt oxide (Co3O4) and copper oxide (Cu2O) under vacuum and open atmosphere has been investigated. The surface feature, bulk density and hardness value of quartz changed after heat treatment, converting to a high value product. Difference in crystallinity of quartz, pre- and post-heat treatment was obtained through X-ray diffraction (XRD) study. The electron probe microanalysis results clearly explicated the diffusion of metal ion in quartz matrix exposed under vacuum atmosphere but as coating on the surface under open atmosphere. The structural transformation of quartz after heat treatment has been observed from the XRD data and well corroborated with the nanoindentation results. Durability of such quartz to chemical hazardous environment was observed. Thus, this communication demonstrates the change in physical and chemical characteristics of natural quartz stone after heat treatment under different atmosphere.

  10. Evaluation of trapping parameters of annealed natural quartz

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Rui [College of Resources, Environment & Tourism, Capital Normal University, 100048 Beijing (China); Shisanling Seismic Station, Institute of Earthquake Science, CEA, 102200 Beijing (China); Wei, Ming-Jian, E-mail: weimj@cnu.edu.cn [College of Resources, Environment & Tourism, Capital Normal University, 100048 Beijing (China); Song, Bo [College of Resources, Environment & Tourism, Capital Normal University, 100048 Beijing (China); Beijing Jing Yuan School, 100040 Beijing (China); Zhang, Yan [College of Resources, Environment & Tourism, Capital Normal University, 100048 Beijing (China); School of TaiPingqiao, Nan Lu of West Railway Station, 100073 Beijing (China); Zhao, Qiu-Yue [Key Laboratory of Tourism and Resources Environment in Universities of Shandong, Taishan University, 271000 Tai’an (China); Pan, Bao-Lin; Li, Teng-Fei [College of Resources, Environment & Tourism, Capital Normal University, 100048 Beijing (China)

    2016-05-15

    The thermoluminescence (TL) trapping parameters of annealed quartz have been investigated. The apparent TL peaks observed at temperatures of 133 °C, 211 °C, 266 °C and 405 °C, respectively, were named Peak I, Peak II, Peak III and Peak IV. The T{sub m} − T{sub stop} method is applied to investigate the number of peaks and their positions, and to obtain the trap distributions in the quartz. Peak shape (PS), Hoogenstraaten method (Various Heating Rates Method, VHR), and Computerized Glow Curve Deconvolution (CGCD) are used to evaluate the trapping parameters of the annealed quartz. The glow curve can be considered as a superposition of at least nine overlapping peaks. These peaks show up at 133 °C, 211 °C, 266 °C, 308 °C, 333 °C, 384 °C, 441 °C, 466 °C and 484 °C. The PS method can be only used in evaluating the parameters for Peaks I. The VHR method can be used in evaluating the trapping parameters for the first three peaks. CGCD method is complementary to obtaining parameters for the sub-peaks, and the thermal quenching correction with the Urbach’s method is necessary. The Urbach’s coefficient for the quartz is 30.03 kT{sub m}.

  11. Using optically stimulated electrons from quartz for the estimation of natural doses

    DEFF Research Database (Denmark)

    Ankjærgaard, Christina; Murray, A.S.; Denby, Phil M.;

    2009-01-01

    quartz samples are studied to examine the possible use of OSE as a chronometer. First the relative variability in OSE and OSL growth curve shapes and the effect of preheat on these are presented, and from these curves, conclusions are drawn concerning the charge movement in natural quartz. Secondly...... dose using the single-aliquot regenerative-dose (SAR) procedure. Finally, a comparative study of the equivalent doses estimated using both OSE and OSL from 10 quartz samples are presented, and it is shown that OSE has a significant potential in retrospective dosimetry....

  12. Experimental microstylolites in quartz and modelling of natural stylolitic structures

    CERN Document Server

    Gratier, Jean-Pierre; Hassani, Riad; Renard, Francois

    2008-01-01

    Experimental microstylolites have been observed at stressed contacts between quartz grains loaded for several weeks in the presence of an aqueous silica solution, at 350 8C and 50 MPa of differential stress. Stereoscopic analysis of pairs of SEM images yielded a digital elevation model of the surface of the microstylolites. Fourier analyses of these microstylolites reveal a self-affine roughness (with a roughness exponent H of 1.2). Coupled with observations of close interactions between dissolution pits and stylolitic peaks, these data illustrate a possible mechanism for stylolite formation. The complex geometry of stylolite surfaces is imposed by the interplay between the development of dissolution peaks in preferential locations (fast dissolution pits) and the mechanical properties of the solid-fluid-solid interfaces. Simple mechanical modeling expresses the crucial competition that could rule the development of microstylolites: (i) a stress-related process, modeled in terms of the stiffness of springs tha...

  13. A study of cathodoluminescence and trace element compositional zoning in natural quartz from volcanic rocks: mapping titanium content in quartz.

    Science.gov (United States)

    Leeman, William P; MacRae, Colin M; Wilson, Nick C; Torpy, Aaron; Lee, Cin-Ty A; Student, James J; Thomas, Jay B; Vicenzi, Edward P

    2012-12-01

    This article concerns application of cathodoluminescence (CL) spectroscopy to volcanic quartz and its utility in assessing variation in trace quantities of Ti within individual crystals. CL spectroscopy provides useful details of intragrain compositional variability and structure but generally limited quantitative information on element abundances. Microbeam analysis can provide such information but is time-consuming and costly, particularly if large numbers of analyses are required. To maximize advantages of both approaches, natural and synthetic quartz crystals were studied using high-resolution hyperspectral CL imaging (1.2-5.0 eV range) combined with analysis via laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). Spectral intensities can be deconvolved into three principal contributions (1.93, 2.19, and 2.72 eV), for which intensity of the latter peak was found to correlate directly with Ti concentration. Quantitative maps of Ti variation can be produced by calibration of the CL spectral data against relatively few analytical points. Such maps provide useful information concerning intragrain zoning or heterogeneity of Ti contents with the sensitivity of LA-ICPMS analysis and spatial resolution of electron microprobe analysis.

  14. The optical absorption of gamma irradiated and heat-treated natural quartz

    Directory of Open Access Journals (Sweden)

    Eduardo Henrique Martins Nunes

    2005-09-01

    Full Text Available Quartz with aluminum as impurity absorbs energy from ionizing radiation and modifies its color. Colorless quartz becomes smoky or dark smoky (morion quartz when exposed to gamma rays. By heat-treatment, smoky quartz may become successively greenish, yellowish, or brownish as the irradiation dose increases. Natural, colorless quartz is routinely colored by irradiation with gamma rays and heat-treatment for jewelry production. The color formation in natural quartz through this procedure is explained based on EPR, UV-VIS, and IR studies of irradiated and irradiated and heat-treated samples. Smoky quartz shows absorption bands in the visible region and a strong EPR signal. After heat-treatment it shows absorption bands in the near UV region with extensions into the visible region and a weak EPR signal. The intensity of the absorption bands is proportional to the irradiation dose. These changes of color are explained by the model of Itoh, Stoneham, and Stoneham. [AlSi O4 /h+]0 centers are produced by irradiation, causing the EPR signal and the absorption bands in the visible region. [AlSi O4]- centers are created from [AlSi O4 /h+]0 centers by heat-treatment. They cannot cause an EPR signal and have absorption bands in the near UV region with extensions into the visible region. The highest concentration of [AlSi O4]- centers occurs when the charge compensators have medium mobility. Lithium should give the best condition for color formation. Sodium (low mobility and hydrogen (high mobility should make smoky quartz colorless after heat-treatment.

  15. Applications of Natural Radiation-Induced Paramagnetic Defects in Quartz to Exploration in Sedimentary Basins

    Institute of Scientific and Technical Information of China (English)

    Pan Y M; Botis S; Nokhrin S

    2006-01-01

    Quartz grains in contact with uranium-bearing minerals or fluids are characterized by natural radiation-induced paramagnetic defects (e. G. , oxygen vacancy centers, silicon vacancy centers, and peroxy radicals), which are amenable to study by electron paramagnetic resonance (EPR) spectroscopy.These natural radiation-induced paramagnetic defects, except for the oxygen vacancy centers, in quartz are concentrated in narrow bands penetrated by α particles: (1) in halos around U- and Th-bearing mineral inclusions and (2) in outer rims or along fractures. The second type of occurrence provides information about uranium mineralization or remobilization (I. E. , sources of uranium, timing of mineralization or remobilization, pathways of uranium-bearing fluids). It can also be used to evaluate sedimentary basins for potential of uranium mineralization. In particular, the peroxy radicals are stable up to 800℃and, therefore, are useful for evaluating metasedimentary rocks (e. G. , Paleoproterozoic metasedimentary sequences in the central zone of the North China craton). EPR study of the Changcheng Series can focus on quartz from the sediment-basement unconformity and faults to determine the presence and types of natural radiation-induced paramagnetic defects, with which to identify and prioritize uranium anomalies. Other potential applications of natural radiation-induced paramagnetic defects in quartz include uranium-bearing hydrocarbon deposits in sedimentary basins. For example, the Junggar, Ordos, and Tarim basins in northwestern China all contain important oil and natural gas fields and are well known for elevated uranium concentrations, including economic sandstone-hosted uranium deposits. Therefore,systematic studies on the distribution of natural radiation-induced paramagnetic defects in quartz from host sedimentary sequences are expected to provide information about the migration of oil and natural gas in those basins.

  16. Updating of the interpretation of the optical absorption and emission of Verneuil synthetic and natural metamorphic blue sapphire: the role of V2+, V3+and Cr2+

    OpenAIRE

    Palanza, V; N. Chiodini; Galli, A.; Lorenzi, R.; Moretti, F.; Paleari, AMF; Spinolo, GM

    2010-01-01

    In the blue colored sapphires of metamorphic origin and Verneuil synthetic studied here, the absorption-emission properties in the VIS-NIR range are largely determined by Cr3+ and Ti3+, as we have been able to demonstrate recently. In that work a sharp radio-luminescence band occurring at 870 nm in Verneuil blue sapphires was left unattributed: here we give evidence for the attribution of that band to the 2E emission transition of V2+, and for the existence of such an emission also in natural...

  17. BARRINGER AWARD ADDRESS: Shock Metamorphism of Quartz in Nature and Experiment: A Review

    Science.gov (United States)

    Stoffler, D.

    1993-07-01

    Quartz as a widespread rock-forming mineral of the Earth's crust represents the most sensitive indicator of impact-induced shock waves and therefore provides an outstanding tool for the recognition of terrestrial impact formations and for the pressure calibration of shock metamorphosed rocks. This paper attempts to summarize the current knowledge in this field. Shocked quartz has been observed in quite variable spatial relations to impact craters: (1) in the crater basement, (2) in rock and mineral clasts of polymict breccias, and (3) in distal ejecta such as tektites and global air- fall beds (e.g., K/T boundary). Quartz displays a wide variety of shock- induced mechanical deformations and transformations [1,2]. Microscopically observable effects are multiple sets of planar fractures (PF) and planar deformation features (PDF) parallel to low indices crystallographic planes; mosaickism; reduced refractivity and birefringence; partial transformation to stishovite; increased optic axial angle; amorphization (diaplectic glass), partial transformation to coesite; and melting (lechatelierite). Additional effects at the atomic scale are well documented by TEM, X-ray diffraction and spectroscopy [3-7]. All types of shock effects observed so far in natural quartz have been reproduced by experimental shock waves in the laboratory and in large scale TNT and nuclear explosions. By means of sophisticated techniques the pressure dependence of shock effects has been calibrated with high precision. Threshold pressures at room temperature (given in GPa) for the onset of certain effects in single crystals and in nonporous quartzofeldpathic rocks are: 7.5 +- 2, 10 +- 2, 20 +- 2 (various PFs and PDFs), 12 +- 1 (stishovite), 25 +- 1 (reduced refractive index and density), ~30 (coesite), 34 +- 1 (total transformation to diaplectic glass), 50 +- 2 (melting and formation of lechatelierite) [8-12]. The type of shock effects, their paragenetic combination, and their formation pressure are

  18. Microstructures and Crystallographic Misorientation in Experimentally Deformed Natural Quartz Single Crystals

    Science.gov (United States)

    Thust, Anja; Heilbronner, Renée.; Stünitz, Holger

    2010-05-01

    Samples of natural milky quartz were deformed in a Griggs deformation apparatus at different confining pressures (700 MPa, 1000 MPa, 1500 MPa), with constant displacement rates of 1 * 10-6s-1, axial strains of 3 - 19%, and at a temperature of 900° C. The single crystal starting material contains a large number of H2O-rich fluid inclusions. Directly adjacent to the fluid inclusions the crystal is essentially dry (50-150H/106Si, determined by FTIR). The samples were cored from a narrow zone of constant 'milkyness' (i.e. same density of fluid inclusions) in a large single crystal in two different orientations (1) normal to one of the prism planes (⊥{m} orientation) and (2) 45° to and to (O+ orientation).During attaining of the experimental P and T conditions, numerous fluid inclusions decrepitate by cracking. Rapid crack healing produces regions of very small fluid inclusions ('wet' quartz domains). Only these regions are subsequently deformed by dislocation glide, dry quartz domains without cracking and decrepitation of fluid inclusions remain undeformed. Sample strain is not sufficient to cause recrystallization, so that deformation is restricted to dislocation glide. In experiments at lower temperatures (800, 700° C) or at lower strain rate (10-5s-1) there is abundant cracking and semi-brittle deformation, indicating that 900° C, (10-6s-1) represents the lower temperature end of crystal plastic deformation in these single crystals. Peak strengths (at 900° C) range between 150 and 250 MPa for most samples of both orientations. There is a trend of decreasing strength with increasing confining pressure, as described by Kronenberg and Tullis (1984) for quartzites, but the large variation in strength due to inhomogeneous sample strain precludes a definite analysis of the strength/pressure dependence in our single crystals. In the deformed samples, we can distinguish a number of microstructures and inferred different slip systems. In both orientations, deformation

  19. Impact of firing on the OSL luminescence properties of natural quartz: A case study

    Energy Technology Data Exchange (ETDEWEB)

    Koul, D.K., E-mail: dkkoul@barc.gov.in [Radiological and Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Polymeris, G.S. [Institute of Nuclear Sciences, Tandogan Campus, 06100 Beşevler, Ankara (Turkey); Soni, A.; Kulkarni, M.S. [Radiological and Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2016-03-01

    A comprehensive study was carried out to observe the impact of firing on the behavior of different features of the optically stimulated luminescence (OSL) signal of geological quartz. The different features which could influence its use in different applications were studied. A comparison of nature of (i) thermoluminescence (TL) glow curves, (ii) OSL decay curves, (iii) pulse annealing curves, (iv) fast and slow components and (v) thermally transferred OSL (TT-OSL) emission of unfired and fired samples suggested a profound influence of thermal firing on the OSL signal. The composition of the OSL signal was seen to get altered by firing treatment; the magnitude of slow component losing its dominance to the fast component. This was true of pulse annealing also, the fired curve looked different from the unfired one. TT-OSL was observed to be larger in unfired sample as compared to the fired sample. Finally, firing was seen to enable reliable dose recovery using single aliquot regenerative (SAR) method, which has not been the case with the unfired sample studied here.

  20. Ultrafine Spherical Quartz Formation during Seismic Fault Slip: Natural and Experimental Evidence and Its Implications

    Science.gov (United States)

    Kuo, L. W.; Song, Y. F.; Yang, C. M.; Song, S. R.; Wang, C. C.; Dong, J. J.; Suppe, J.; Shimamoto, T.

    2015-12-01

    In recent works on the determination of pseudotachylyte within the principal slip zone (PSZ) of the Chelungpu fault (Taiwan), we demonstrated that frictional melting occurred at shallow depths during the 1999 Mw 7.6 Chi-Chi earthquake. Thus, the characteristics of melts are of paramount importance to investigate processes controlling dynamic fault mechanics during seismic slips. We conducted rock friction experiments on siltstone recovered from the Taiwan Chelungpu fault Drilling Project (TCDP) at a slip rate of 1.3 m/s and a normal stress of 1 MPa. Here we not only target to characterize experimental pseudotachylyte and evaluate the associated frictional behavior, but compare it with natural frictional melts of TCDP. Our results show (1) initial shear stress drop was related to the generation of low viscosity melt patches, (2) the evolution of shear stress in the postmelting regime was congruent with frictional melt rheology, and (3) the slip strengthening was presumably resulted from dehydration of the frictional melt. In particular, the state-of-art of in situ synchrotron analyses (X-ray diffraction and Transmission X-ray Microscope) determine the presence of ultrafine spherical quartz (USQ) (~10 nm to 50 nm) in the glassy matrices presumably produced at high temperature. Our observations confirm that the USQ formed in rock friction experiments do occur in natural faults. We surmise the USQ is the result of frictional melting on siltstone and represents the latest slip zones of the Chelungpu fault, and further infer that the viscous melts may terminate seismic slips at shallow crustal conditions.

  1. Effect of high gamma-doses in the sensitization of natural quartz for thermoluminescence dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Khoury, H.J.; Guzzo, P.L.; Brito, S.B. [Universidade Federal de Pernambuco, 50740-540 Recife PE (Brazil)

    2006-07-01

    Sensitization is an important effect in radiation dosimetry using thermoluminescent (TL materials where the enhancement of sensitivity is a desirable feature. Until known, the investigation of sensitization in quartz has been restricted to its first glow peak appearing around 110 C. In addition, the sensitization process has been essentially produced by heat-treatments in powdered quartz. The aim of this study is to investigate the sensitization process in the second glow peak of crystalline quartz using high doses of gamma irradiation. For this, five lots of samples were prepared from quartz single crystals issued from different geologies in Brazil. Chips of 5 x 5 x 1 mm{sup 3} (60 mg) were cut and lapped parallel to the (0001) plane. The specimens were initially irradiated with doses of gamma radiation of {sup 137} Cs in the range of 10 mGy to 10 Gy in order to determine its TL response curve. After that, the specimens were submitted to successive high doses of gamma-irradiation with {sup 60} Co from 25 kGy to 350 kGy. After each irradiation, the TL response curves to gamma radiation of {sup 137} Cs were determined for each quartz lot irradiated in the range of 2 to 20 mGy. The TL measurements were carried out with a 2800M Victoreen reader using the step mode. The step parameters were set in 10 s from 30 to 160 C (first region) and in 20 s from 160 to 320 C (second region). The absolute TL signal used to obtain the calibration curves represented the sum of electric charges under the glow peak appearing in the second region. The results showed that the TL response of the quartz studied increased with the dose sensitization, so that the TL response for 10mGy of {sup 137} Cs radiation varied from 0.05 nC/mg for the quartz without sensitization to 10 nC/mg after a sensitization with 50 kGy of gamma radiation of {sup 60} Co. The effect of sensitization with high doses of gamma irradiation was clearly observed for three quartz lots and it was observed that the high

  2. Mobility of nanosized cerium dioxide and polymeric capsules in quartz and loamy sands saturated with model and natural groundwaters.

    Science.gov (United States)

    Petosa, Adamo Riccardo; Ohl, Carolin; Rajput, Faraz; Tufenkji, Nathalie

    2013-10-01

    The environmental and health risks posed by emerging engineered nanoparticles (ENPs) released into aquatic environments are largely dependent on their aggregation, transport, and deposition behavior. Herein, laboratory-scale columns were used to examine the mobility of polyacrylic acid (PAA)-coated cerium dioxide nanoparticles (nCeO2) and an analogous nanosized polymeric capsule (nCAP) in water saturated quartz sand or loamy sand. The influence of solution ionic strength (IS) and cation type (Na(+), Ca(2+), or Mg(2+)) on the transport potential of these ENPs was examined in both granular matrices and results were also compared to measurements obtained using a natural groundwater. ENP suspensions were characterized using dynamic light scattering and nanoparticle tracking analysis to establish aggregate size, and laser Doppler electrophoresis to determine ENP electrophoretic mobility. Regardless of IS, virtually all nCeO2 particles suspended in NaNO3 eluted from the quartz sand-packed columns. In contrast, heightened nCeO2 and nCAP particle retention and dynamic (time-dependent) transport behavior was observed with increasing concentrations of the divalent salts and in the presence of natural groundwater. Enhanced particle retention was also observed in loamy sand in comparison to the quartz sand, emphasizing the need to consider the nature of the aqueous matrix and granular medium in evaluating contamination risks associated with the release of ENPs in natural and engineered aquatic environments.

  3. Fundamental investigations of natural and laboratory generated SAR dose response curves for quartz OSL in the high dose range

    DEFF Research Database (Denmark)

    Timar-Gabor, Alida; Constantin, Daniela; Buylaert, Jan-Pieter

    2015-01-01

    SAR-OSL investigations on quartz from Romanian loess resulted in non concordant fine and coarse-grain ages for equivalent doses higher than ~100 Gy. The laboratory dose response for both grain sizes is well represented by a sum of two saturating exponential functions, fine and coarse grains chara...... equivalent dose of 2000e2500 Gy were found to be below the saturation level of the laboratory dose response curve for both grain sizes; this also applied to the luminescence signals measured after >5000 Gy given on top of natural doses. © 2015 Elsevier Ltd. All rights reserved....... characterised by D01 and D02 values of ~140 and ~1400 Gy and ~65 and ~650 Gy respectively. Pulsed OSL experiments confirmed that this behaviour is almost certainly inherent to quartz and not caused by contamination with another mineral. Natural doseeresponse curves do not follow the same pattern and enter...... saturation much earlier. Analysis of time resolved spectra indicated similar luminescence lifetimes for both fine and coarse quartz grains, and natural and laboratory generated OSL signals seem to use the same non-dosedependent recombination pathways. The natural signals of a sample with an expected...

  4. Interlaboratory beta source calibration using TL and OSL on natural quartz

    DEFF Research Database (Denmark)

    Goksu. H.Y.; Bailiff, I.K.; Bøtter-Jensen, L.

    1995-01-01

    Laboratory at GSF using a Go-60 source as well as the in situ measurements with an ionization chamber, calibrated to the primary standards of PTB Braunschweig. Irradiated and unirradiated quartz was distributed to the five laboratories and although different procedures were used for thermoluminescence...

  5. Si-29 NMR spectroscopy of naturally-shocked quartz from Meteor Crater, Arizona: Correlation to Kieffer's classification scheme

    Science.gov (United States)

    Boslough, M. B.; Cygan, R. T.; Kirkpatrick, R. J.

    1993-01-01

    We have applied solid state Si-29 nuclear magnetic resonance (NMR) spectroscopy to five naturally-shocked Coconino Sandstone samples from Meteor Crater, Arizona, with the goal of examining possible correlations between NMR spectral characteristics and shock level. This work follows our observation of a strong correlation between the width of a Si-29 resonance and peak shock pressure for experimentally shocked quartz powders. The peak width increase is due to the shock-induced formation of amorphous silica, which increases as a function of shock pressure over the range that we studied (7.5 to 22 GPa). The Coconino Sandstone spectra are in excellent agreement with the classification scheme of Kieffer in terms of presence and approximate abundances of quartz, coesite, stishovite, and glass. We also observe a new resonance in two moderately shocked samples that we have tentatively identified with silicon in tetrahedra with one hydroxyl group in a densified form of amorphous silica.

  6. Thermal Conductance through Sapphire-Sapphire Bonding

    Science.gov (United States)

    Suzuki, T.; Tomaru, T.; Haruyama, T.; Shintomi, T.; Uchinyama, T.; Miyoki, S.; Ohashi, M.; Kuroda, K.

    2003-07-01

    Thermal conductance on sapphire-sapphire bonded interface has been investigated. Two pieces of single crystal sapphire bar with square cross section were bonded together by adhesion free bonding. In two sections of the bar, thermal conductivity was measured between 5 K to 300K. One section contains a bonded interface and the other section measured a thermal conductivity of the sapphire as a reference. No significant thermal resistance due to bonded interface was found from this measurement. Obtained thermal conductivity reaches κ 1 × 104 [W/m·K] in temperature range of T = 20 ˜ 30 K which is a planned operating temperature of a cryogenic mirror of the Large scale Cryogenic Gravitational wave telescope. It looks promising for sapphire bonding technique to improve a heat transfer from a large cryogenic mirror to susp ension wires.

  7. Manufacturing polycrystalline pellets of natural quartz for applications in thermoluminescence dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho Junior, Alvaro Barbosa de; Khoury, Helen Jamil [Federal University of Pernambuco (UFPE), Recife, PE (Brazil). Department of Nuclear Energy; Barros, Thiago Fernandes; Guzzo, Pedro Luiz [Federal University of Pernambuco (UFPE), Recife, PE (Brazil). Department of Mining Engineering

    2012-07-15

    This paper describes the manufacturing process of quartz-pellets and shows their potential use as thermoluminescence dosimeters (TLD) for those applications where low-levels of ionising radiation are present. Two batches of cold-pressed pellets were produced and their resistance were evaluated by vibration tests and weight-loss measurements. The batch manufactured with 75 Multiplication-Sign 150 Micro-Sign m particles showed enough resistance to be employed as TLD. The dosimetric properties of the 310 Degree-Sign C peak appearing in the glow curves of these pellets were characterized together with commercial TLD-100 units using {gamma}- and X-ray beams with different energies. The uncertainties related to reproducibility and stability of the TL signal were better than 10%. The sensitivity and the linearity of the TL response of quartz-pellets were better than that measured for TLD-100 for doses ranging from 0.5 to 200mGy. The energy dependence of the quartz-pellets was higher than that of TLD-100 but it cannot be considered a restriction to their use in clinical procedures and industrial applications. (author)

  8. Updating of the interpretation of the optical absorption and emission of Verneuil synthetic and natural metamorphic blue sapphire: the role of V2+, V3+ and Cr2+

    Science.gov (United States)

    Palanza, V.; Chiodini, N.; Galli, A.; Lorenzi, R.; Moretti, F.; Paleari, A.; Spinolo, G.

    2010-11-01

    In the blue colored sapphires of metamorphic origin and Verneuil synthetic studied here, the absorption-emission properties in the VIS-NIR range are largely determined by Cr3+ and Ti3+, as we have been able to demonstrate recently. In that work a sharp radio-luminescence band occurring at 870 nm in Verneuil blue sapphires was left unattributed: here we give evidence for the attribution of that band to the 2E emission transition of V2+, and for the existence of such an emission also in natural samples of metamorphic origin. After such a result, we accurately evaluated by EDXRF the V concentrations in various samples and found the ion more ubiquitous than foreseen. We then searched for and found, weak but diagnostic spin forbidden transitions and phonon sequencies in the absorption spectra of samples sufficiently rich in V. The experimental results just mentioned allowed us to discuss the effects of the overlap of V3+ and Cr3+ spin-allowed absorption bands on the spectrum of the varieties of corundum under study. To complete the updating of the interpretation, we spent a further effort to strengthen the attribution of the absorption band at 14500 cm-1 (currently interpreted as an IVCT (Fe2+ → Fe3+)) to the 5E→5T2 transitions of Cr2+.

  9. Comparative study on the effect of annealing treatments on RTL mechanism in natural quartz from different origins

    Energy Technology Data Exchange (ETDEWEB)

    Mebhah, D., E-mail: mebhahd@yahoo.f [Centre de Recherche Nucleaire d' Alger, 2 Bd, Frantz Fanon, BP 399 (Algeria); Imatoukene, D.; Lounis-Mokrani, Z. [Centre de Recherche Nucleaire d' Alger, 2 Bd, Frantz Fanon, BP 399 (Algeria); Kechouane, M. [Faculte de Physique, USTHB, BP 32 El Alia (Algeria)

    2009-12-15

    The behaviour of trap centres and luminescence centres has been investigated for fired and unfired natural quartz from bricks and sediments irradiated at 100 Gy and annealed at different temperatures in the range 350-700 deg. C. The annealing treatment affects thermoluminescence (TL) glow curve as various changes were observed. The higher sensitization occurred for an annealing in the region 550-600 deg. C. At this annealing temperature, it has been observed the emergence of two peaks arising at 96 and 180 deg. C. At lower annealing temperatures, these peaks are overlapped by the peaks localized at 90 and 195 deg. C, respectively. Concerning the fired quartz, the higher sensitization occurred for an annealing in the region 500-550 deg. C for peak temperature around 200 deg. C and an unusual desensitization for the peak temperature around 100 deg. C. The behaviour of the two types of quartz is analyzed regarding to their kinetic parameters and luminescence emission and compared to literature data.

  10. Study of the relation of the band at 3595 CM{sup -1} in FTIR spectrum of natural quartz with color development by gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Helena Cristina M.; Lameiras, Fernando S., E-mail: helenacrisms@gmail.com, E-mail: fsl@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-07-01

    Brazil is a major producer of gemological quartz as smoky quartz, morion, citrine, amethyst, and prasiolite. Due to its abundance, hardness, and color varieties, quartz is used in jewelry industry. However, very often quartz is found in nature colorless or with faint colors, which requires exposure to ionizing radiation for color enhancement or development. Not all quartz can develop color. Chromophore chemical elements must be present in suitable proportions for color development after irradiation and heating. Infrared spectrometry is used to separate the quartz that can develop colors from the ones that cannot. Bands in infrared spectrum can indicate the presence and relative contents of chromophore chemical elements, such as aluminum, iron, lithium, sodium, and hydrogen. Some samples of colorless quartz show a band at 3595 cm{sup -1} whose origin is yet not assigned. Samples of quartz with a prominent band at 3595 cm{sup -1} were exposed to gamma rays and heating to observe its behavior. From the statistical point of view, no modification was observed on the position and amplitude of this band after irradiation up 75 kGy and heating to 300-330 deg C. This study should be completed with samples of different origins and higher doses, as well as chemical analyses of trace chemical elements in the samples. (author)

  11. Natural quartz TL property and similarity in Piper nigrum L; Propiedad TL de cuarzo natural y similitud en pimienta negra (Piper nigrum L.)

    Energy Technology Data Exchange (ETDEWEB)

    Guzman A, S.; Cruz Z, E.; Furetta, C. [Unidad de Irradiacion y Seguridad Radiologica, Instituto de Ciencias Nucleares, UNAM, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Brown, F. [Departamento de Investigacion en Polimeros y Materiales, Universidad de Sonora, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Barboza F, M. [Centro de Investigacion en Fisica, Universidad de Sonora, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico)], e-mail: ecruz@nucleares.unam.mx

    2009-10-15

    Quartz is a mineral abundant in nature and can provide information thermoluminescent (TL), and also is located in the mineral fraction of some herbs and spices consumed. It is present the analysis of the TL properties of a sample of natural quartz rock and compared with those obtained from the fraction of Piper nigrum L. poly mineral when they were exposed to {sup 60}Co gamma radiation. The poly minerals of Piper nigrum L. were analyzed by X-ray diffraction, where the quartz was found as a major component. They separated in different particle sizes (10, 53, 74 and 149 {mu}m). The samples were irradiated at relatively low doses (1-500 Gy) and high (0.1-40 kGy) in order to determine the linearity of the TL emission as a function of the dose and the analysis of glow curves. Also there was the fading of the TL signal, the effect of ultra violet light. The reproducibility of the TL signal in the samples indicates that a smaller particle size gives better TL signal. (author)

  12. Experimental Investigations of Signals of a New Nature with the aid of two High Precision Stationary Quartz Gravimeters

    CERN Document Server

    Baurov, Yu A; Baurov, Yu.A.

    2001-01-01

    In consequence of long-term (2000) observation of a system of two high-precision quartz gravimeters (one of them with an attached magnet) placed in a special (at a depth of $\\sim $10m) gravimetric laboratory on a common base separated from the foundation of the building, signals of a new nature were detected. They were of a smooth peak-type shape, several minutes duration, and with amplitudes often more than that of the moon tide. The nature of the signals cannot be explained in the framework of traditional physical views but can be qualitatively described with the aid of a supposed new interaction connected with the hypothesis about the existence of the cosmological vectorial potential A_g, a new presumed fundamental vectorial constant.

  13. Evidence of colour-modification induced charge and structural disorder in natural corundum: Spectroscopic studies of beryllium treated sapphires and rubies

    Science.gov (United States)

    Sastry, M. D.; Mane, Sandesh N.; Gaonkar, Mahesh P.; Bagla, H.; Panjikar, J.; Ramachandran, K. T.

    2009-07-01

    Corundum α - Al2O3 single crystals is an important gemstone known by different names depending on the colour it exhibits which in turn depends on the impurities that are present. The colour depends on the valence state of the impurity element present in corundum (Cr3+ in ruby, Fe3+ in yellow sapphire and Fe-Ti complex in blue sapphire). There have been a number of reports of diffusion controlled high temperature chemical reactions to influence the colouration in these materials. Present paper deals with the Raman and FT-IR results on Be treated rubies/sapphires and gives evidence of the disorder brought about by such treatments. This can be effectively used for diagnostic purposes for detecting the treated stones.

  14. Evidence of colour-modification induced charge and structural disorder in natural corundum: Spectroscopic studies of beryllium treated sapphires and rubies

    Energy Technology Data Exchange (ETDEWEB)

    Sastry, M D; Mane, Sandesh N; Gaonkar, Mahesh P; Panjikar, J; Ramachandran, K T [Gemmological Institute of India, 304 Sukhsagar Building, N.S.Patkar Marg, Opera House, Mumbai 400 007 (India); Bagla, H, E-mail: mdsastry@yahoo.co.in [Department of Chemistry, KC College, Church gate, Mumbai 400 020 (India)

    2009-07-15

    Corundum {alpha} - Al{sub 2}O{sub 3} single crystals is an important gemstone known by different names depending on the colour it exhibits which in turn depends on the impurities that are present. The colour depends on the valence state of the impurity element present in corundum (Cr{sup 3+} in ruby, Fe{sup 3+} in yellow sapphire and Fe-Ti complex in blue sapphire). There have been a number of reports of diffusion controlled high temperature chemical reactions to influence the colouration in these materials. Present paper deals with the Raman and FT-IR results on Be treated rubies/sapphires and gives evidence of the disorder brought about by such treatments. This can be effectively used for diagnostic purposes for detecting the treated stones.

  15. Characterisation of a natural quartz crystal as a reference material for microanalytical determination of Ti, Al, Li, Fe, Mn, Ga and Ge

    Science.gov (United States)

    Audetat, Andreas; Garbe-Schonberg, Dieter; Kronz, Andreas; Pettke, Thomas; Rusk, Brian G.; Donovan, John J.; Lowers, Heather

    2015-01-01

    A natural smoky quartz crystal from Shandong province, China, was characterised by laser ablation ICP-MS, electron probe microanalysis (EPMA) and solution ICP-MS to determine the concentration of twenty-four trace and ultra trace elements. Our main focus was on Ti quantification because of the increased use of this element for titanium-in-quartz (TitaniQ) thermobarometry. Pieces of a uniform growth zone of 9 mm thickness within the quartz crystal were analysed in four different LA-ICP-MS laboratories, three EPMA laboratories and one solution-ICP-MS laboratory. The results reveal reproducible concentrations of Ti (57 ± 4 μg g-1), Al (154 ± 15 μg g-1), Li (30 ± 2 μg g-1), Fe (2.2 ± 0.3 μg g-1), Mn (0.34 ± 0.04 μg g-1), Ge (1.7 ± 0.2 μg g-1) and Ga (0.020 ± 0.002 μg g-1) and detectable, but less reproducible, concentrations of Be, B, Na, Cu, Zr, Sn and Pb. Concentrations of K, Ca, Sr, Mo, Ag, Sb, Ba and Au were below the limits of detection of all three techniques. The uncertainties on the average concentration determinations by multiple techniques and laboratories for Ti, Al, Li, Fe, Mn, Ga and Ge are low; hence, this quartz can serve as a reference material or a secondary reference material for microanalytical applications involving the quantification of trace elements in quartz.

  16. Fundamental investigations of natural and laboratory generated SAR dose response curves for quartz OSL in the high dose range

    DEFF Research Database (Denmark)

    Timar-Gabor, Alida; Constantin, Daniela; Buylaert, Jan-Pieter;

    2015-01-01

    SAR-OSL investigations on quartz from Romanian loess resulted in non concordant fine and coarse-grain ages for equivalent doses higher than ~100 Gy. The laboratory dose response for both grain sizes is well represented by a sum of two saturating exponential functions, fine and coarse grains chara...

  17. Updating of the interpretation of the optical absorption and emission of Verneuil synthetic and natural metamorphic blue sapphire: the role of V{sup 2+}, V{sup 3+} and Cr{sup 2+}

    Energy Technology Data Exchange (ETDEWEB)

    Palanza, V; Chiodini, N; Galli, A; Lorenzi, R; Moretti, F; Paleari, A; Spinolo, G, E-mail: giorgio.spinolo@mater.unimib.it [Department of Materials Science, University of Milano-Bicocca, Via Cozzi 53, Milano 20125 (Italy)

    2010-11-15

    In the blue colored sapphires of metamorphic origin and Verneuil synthetic studied here, the absorption-emission properties in the VIS-NIR range are largely determined by Cr{sup 3+} and Ti{sup 3+}, as we have been able to demonstrate recently. In that work a sharp radio-luminescence band occurring at 870 nm in Verneuil blue sapphires was left unattributed: here we give evidence for the attribution of that band to the {sup 2}E emission transition of V{sup 2+}, and for the existence of such an emission also in natural samples of metamorphic origin. After such a result, we accurately evaluated by EDXRF the V concentrations in various samples and found the ion more ubiquitous than foreseen. We then searched for and found, weak but diagnostic spin forbidden transitions and phonon sequencies in the absorption spectra of samples sufficiently rich in V. The experimental results just mentioned allowed us to discuss the effects of the overlap of V{sup 3+} and Cr{sup 3+} spin-allowed absorption bands on the spectrum of the varieties of corundum under study. To complete the updating of the interpretation, we spent a further effort to strengthen the attribution of the absorption band at 14500 cm{sup -1} (currently interpreted as an IVCT (Fe{sup 2+} {yields} Fe{sup 3+})) to the {sup 5}E{yields}{sup 5}T{sub 2} transitions of Cr{sup 2+}.

  18. Quartz preferred orientation in naturally deformed mylonitic rocks (Montalto shear zone-Italy): a comparison of results by different techniques, their advantages and limitations

    Science.gov (United States)

    Fazio, Eugenio; Punturo, Rosalda; Cirrincione, Rosolino; Kern, Hartmut; Pezzino, Antonino; Wenk, Hans-Rudolf; Goswami, Shalini; Mamtani, Manish A.

    2016-12-01

    In the geologic record, the quartz c-axis patterns are widely adopted in the investigation of crystallographic preferred orientations (CPO) of naturally deformed rocks. To this aim, in the present work, four different methods for measuring quartz c-axis orientations in naturally sheared rocks were applied and compared: the classical universal stage technique, the computer-integrated polarization microscopy method (CIP), the time-of-flight (TOF) neutron diffraction analysis , and the electron backscatter diffraction (EBSD). Microstructural analysis and CPO patterns of quartz, together with the ones obtained for feldspars and micas in mylonitic granitoid rocks, have been then considered to solve structural and geological questions related to the Montalto crustal scale shear zone (Calabria, southern Italy). Results obtained by applying the different techniques are discussed, and the advantages as well as limitations of each method are highlighted. Importantly, our findings suggest that patterns obtained by means of different techniques are quite similar. In particular, for such mylonites, a subsimple shear (40% simple shear vs 60% pure shear) by shape analysis of porphyroclasts was inferred. A general tendency of an asymmetric c-maximum near to the Z direction (normal to foliation) suggesting dominant basal slip, consistent with fabric patterns related to dynamically recrystallization under greenschist facies, is recognized. Rhombohedral slip was likely active as documented by pole figures of positive and negative rhombs (TOF), which reveal also potential mechanical Dauphiné twinning. Results showed that the most complete CPO characterization on deformed rocks is given by the TOF (from which also other quartz crystallographic axes can be obtained as well as various mineral phases may be investigated). However, this use is restricted by the fact that (a) there are very few TOF facilities around the world and (b) there is loss of any domainal reference, since TOF is a

  19. Thermal modeling of the NASA-Ames Research Center Cryogenic Optical Test Facility and a single-arch, fused-natural-quartz mirror

    Science.gov (United States)

    Ng, Y. S.; Augason, Gordon C.; Young, Jeffrey A.; Howard, Steven D.; Melugin, Ramsey K.

    1990-01-01

    A thermal model of the dewar and optical system of the Cryogenic Optical Test Facility at NASA-Ames Research Center was developed using the computer codes SINDA and MONTE CARLO. The model was based on the geometry, boundary conditions, and physical properties of the test facility and was developed to investigate heat transfer mechanisms and temperatures in the facility and in test mirrors during cryogenic optical tests. A single-arch, fused-natural-quartz mirror was the first mirror whose thermal loads and temperature distributions were modeled. From the temperature distribution, the thermal gradients in the mirror were obtained. The model predicted that a small gradient should exist for the single arch mirror. This was later verified by the measurement of mirror temperatures. The temperatures, predicted by the model at various locations within the dewar, were in relatively good agreement with the measured temperatures. The model is applicable to both steady-state and transient cooldown operations.

  20. Thermal modeling of the NASA-Ames Research Center Cryogenic Optical Test Facility and a single-arch, fused-natural-quartz mirror

    Science.gov (United States)

    Ng, Y. S.; Augason, Gordon C.; Young, Jeffrey A.; Howard, Steven D.; Melugin, Ramsey K.

    1990-11-01

    A thermal model of the dewar and optical system of the Cryogenic Optical Test Facility at NASA-Ames Research Center was developed using the computer codes SINDA and MONTE CARLO. The model was based on the geometry, boundary conditions, and physical properties of the test facility and was developed to investigate heat transfer mechanisms and temperatures in the facility and in test mirrors during cryogenic optical tests. A single-arch, fused-natural-quartz mirror was the first mirror whose thermal loads and temperature distributions were modeled. From the temperature distribution, the thermal gradients in the mirror were obtained. The model predicted that a small gradient should exist for the single arch mirror. This was later verified by the measurement of mirror temperatures. The temperatures, predicted by the model at various locations within the dewar, were in relatively good agreement with the measured temperatures. The model is applicable to both steady-state and transient cooldown operations.

  1. World's largest sapphire for many applications

    Science.gov (United States)

    Khattak, Chandra P.; Shetty, Raj; Schwerdtfeger, C. Richard; Ullal, Saurabh

    2016-10-01

    Sapphire has been used for many high technology applications because of its excellent optical, mechanical, high temperature, abrasion resistance and dielectric properties. However, it is expensive and the volume of sapphire used has been limited. The potential sapphire requirements for LED and consumer electronic applications are very high. Emphasis has been on producing larger sapphire boules to achieve significant cost reductions so these applications are realized. World's largest sapphire boules, 500 mm diameter 300+kg, have been grown to address these markets.

  2. Pumping of titanium sapphire laser

    Science.gov (United States)

    Jelínková, H.; Vaněk, P.; Valach, P.; Hamal, K.; Kubelka, J.; Škoda, V.; Jelínek, M.

    1993-02-01

    Two methods of Ti:Sapphire pumping for the generation of tunable laser radiation in the visible region were studied. For coherent pumping, the radiation of the second harmonic of a Nd:YAP laser was used and a maximum output energy of E out=4.5 mJ was reached from the Ti:Sapphire laser. For noncoherent pumping, two different lengths of flashlamp pulses were used and a maximum of E out=300 mJ was obtained. Preliminary estimations of the wavelength range of tunability were made.

  3. Neutron Transmission through Sapphire Crystals

    DEFF Research Database (Denmark)

    Sapphire crystals are excellent filters of fast neutrons, while at the same time exhibit moderate to very little absorption at smaller energies. We have performed an extensive series of measurements in order to quantify the above effect. Alongside our experiments, we have performed a series...... of simulations, in order to reproduce the transmission of cold neutrons through sapphire crystals. Those simulations were part of the effort of validating and improving the newly developed interface between the Monte-Carlo neutron transport code MCNP and the Monte Carlo ray-tracing code McStas....

  4. A sapphire tube atomizer for on-line atomization and in situ collection of bismuthine for atomic absorption spectrometry

    OpenAIRE

    Musil, S. (Stanislav); Dědina, J. (Jiří)

    2013-01-01

    Sapphire was tested as a new material for volatile species atomizers and bismuthine was chosen as a convenient model for volatile species. Its performance was compared with a quartz atomizer in both modes of operation - on-line atomization versus in situ collection.

  5. Laser welding of fused quartz

    Science.gov (United States)

    Piltch, Martin S.; Carpenter, Robert W.; Archer, III, McIlwaine

    2003-06-10

    Refractory materials, such as fused quartz plates and rods are welded using a heat source, such as a high power continuous wave carbon dioxide laser. The radiation is optimized through a process of varying the power, the focus, and the feed rates of the laser such that full penetration welds may be accomplished. The process of optimization varies the characteristic wavelengths of the laser until the radiation is almost completely absorbed by the refractory material, thereby leading to a very rapid heating of the material to the melting point. This optimization naturally occurs when a carbon dioxide laser is used to weld quartz. As such this method of quartz welding creates a minimum sized heat-affected zone. Furthermore, the welding apparatus and process requires a ventilation system to carry away the silicon oxides that are produced during the welding process to avoid the deposition of the silicon oxides on the surface of the quartz plates or the contamination of the welds with the silicon oxides.

  6. Simulation of quartz resonators

    Science.gov (United States)

    Weinmann, M.; Radius, R.; Mohr, R.

    Quartz resonators are suitable as novel sensor elements in the field of profilometry and three dimensional measurement techniques. This application requires a tailoring of the oscillator circuit which is performed by a network analysis program. The equivalent network parameters are computed by a finite element analysis. The mechanical loading of the quartz is modeled by a viscous damping approach.

  7. Hydrogen effect on the properties of sapphire

    Science.gov (United States)

    Mogilevsky, Radion N.; Sharafutdinova, Liudmila G.; Nedilko, Sergiy; Gavrilov, Valeriy; Verbilo, Dmitriy; Mittl, Scott D.

    2009-05-01

    Sapphire is a widely used material for optical, electronic and semiconductor applications due to its excellent optical properties and very high durability. Optical and mechanical properties of sapphire depend on many factors such as the starting materials that are used to grow crystals, methods to grow sapphire crystals, etc. Demand for highest purity and quality of sapphire crystals increased ten fold for the last several years due to new applications for this material. In this work we studied the effect of starting materials and crystal growth methods on the optical and mechanical properties of sapphire, especially concentrating on the effect of hydrogen on the properties of sapphire. It was found that the infrared (IR) absorption which is traditionally used to measure the hydrogen content in sapphire crystals cannot be reliably used and the data obtained by this method provides a much lower hydrogen concentration than actual. We have shown for the first time that Nuclear Magnetic Resonance techniques can be successfully used to determine hydrogen concentration in sapphire crystals. We have shown that hydrogen concentration in sapphire can reach thousands of ppm if these crystals are grown from Verneuil starting material or aluminum oxide powder. Alternatively, the hydrogen concentration is very low if sapphire crystals are grown from High Purity Densified Alumina (HPDA®) as a starting material. HPDA® is produced by EMT, Inc through their proprietary patented technology. It was found that optical and mechanical properties of sapphire crystals grown using EMT HPDA® starting material are much better than those sapphire crystals grown using a starting material of Verneuil crystals or aluminum oxide powder.

  8. Measurement of natural radioactivity in granites and its quartz-bearing gold at El-Fawakhir area (Central Eastern Desert, Egypt

    Directory of Open Access Journals (Sweden)

    M.A.M. Uosif

    2015-07-01

    Full Text Available The distribution of natural radionuclides (226Ra, 232Th and 40K in Granites and its quartz-bearing gold at El-Fawakhir area (Central Eastern Desert, Egypt were measured by using γ-ray spectroscopy [NaI (Tl 3″ × 3″]. X-Ray Fluorescence technique was used for chemical analyses of the studied samples. The specific activity of 226Ra, 232Th and 40K values are in range (3 ± 0.5 to 43 ± 2 Bqkg−1, (5 ± 0.7 to 41 ± 2 Bqkg−1 and (128 ± 6 to 682 ± 35 Bqkg−1 respectively. The absorbed dose rates ranged from 13.8 to 58.4 nGy h−1, where the total effective dose rates were determined to be between 16.7 and 70.9 μSvy−1. The maximum external hazard index (Hex is 0.3 nGyh−1. The calculated values of the excess lifetime cancer risks (ELCR and annual effective dose rate values are in between (8.48 × 10−5 and 2.63 × 10−4 and (24.2 and 72.9 μSvy−1 respectively. Geochemically, the studied granites consist of major oxides, they are characterized by SiO2, K2O, Na2O, Al2O3, and depleted in CaO, MgO, TiO2, and P2O5. The average absorbed dose rate (Do in air is 37.8 nGyh−1 for the whole studied samples, this value is about 3.78% of the 1.0 mSvy−1 recommended by (ICRP-60,1991 to the public, so there is no radiological risk for the workers in that area.

  9. Radiation Damage of Quartz Fibers

    CERN Document Server

    Hagopian, V

    1999-01-01

    Quartz fibers are used in high energy physics experiments as the active medium in high radiation area calorimetry. Quartz fibers are also used in the transmission of optical signals. Even though quartz does not damage by moderate amounts of irradiation, the clad of the fibers and the protective coating ( buffer) do damage reducing light transmission. Various types of quartz fibers have been irradiated and measured for light transmission. The most radiation hard quartz fibers are those with quartz clad and aluminum buffer.

  10. Luminescence sensitivity changes in quartz

    CERN Document Server

    Wintle, A G

    1999-01-01

    In the luminescence dating of sedimentary or heated quartz, some heat treatment is usually applied to the sample immediately prior to the measurement of the optically stimulated luminescence. In this paper we report experiments on a 30,000-year-old sedimentary quartz, in which we use the luminescence response to a test dose to monitor the changes in sensitivity that are caused by holding the quartz at temperatures from 160 to 280 deg. C for times from 10 s to 22 h. For an optically bleached sample, the monitoring is by both optically stimulated luminescence and the 110 deg. C TL peak; both luminescence signals are shown to have the same sensitisation (i.e. activation energy) characteristics. For natural or laboratory irradiated samples only the 110 deg. C TL peak can be used; sensitivity increases of up to a factor of 1.3 and 3 are observed for the natural and laboratory irradiated aliquots, respectively. Up to four exponential components are used to deconvolve the sensitivity change data; the dominant compon...

  11. QUARTZ FIBER ELECTROSCOPES

    Science.gov (United States)

    Henderson, R.P.

    1957-09-17

    An instrument carried unobtrusively about the person such as in a finger ring to indicate when that person has been exposed to an unusual radiation hazard is described. A metallized quartz fiber is electrically charged to indicate a full scale reading on an etched glass background. The quartz fiber and the scale may be viewed through a magnifying lens for ease of reading. Incident radiation will ionize gaseous particles in the sealed structure thereby allowing the charge to leak off the quartz fiber with its resulting movement across the scale proportionally indicating the radiation exposure.

  12. Mechanical twinning in small quartz crystals

    Science.gov (United States)

    Laughner, J. W.; Newnham, R. E.; Cross, L. E.

    1982-02-01

    Quartz is known to be ferrobielastic; that is, quartz crystals have domain states (Dauphiné twins) which differ in their elastic compliance values and which can be switched by an appropriately oriented stress. Polycrystalline quartz has also been reported (Tullis 1970) to show preferential orientation of these domains following application of large uniaxial stresses. These experiments were designed to study twinning of synthetic quartz “grains” (minimum size 0.07×0.07×0.02 cm) in specially-constructed composites and of grains in three natural quartz aggregates — a quartzite, a novaculite, and a jasper. Backreflection X-ray techniques were used to verify twinning in the composite grains, while special electroding and electrical detection allowed the twinning processes to be examined in “real time.” Small synthetic quartz crystals were found to behave identically to the massive samples previously studied. Electrical pulses due to the reversal of piezoelectric coefficient d 11 in twinned quartz were detected from quartzite and from the man-made composites. Novaculite also gave electrical pulses which were probably from twinning (evidenced by the correlation of expected and observed pulse sizes and shapes), while no pulses from the jaspers indicative of twinning were detected. Grain size distribution differences are considered the main structural reason for the different behaviors.

  13. Vacuum electrolysis of quartz

    Science.gov (United States)

    King, James Claude

    1976-01-13

    The disclosure is directed to a method for processing quartz used in fabricating crystal resonators such that transient frequency change of resonators exposed to pulse irradiation is virtually eliminated. The method involves heating the crystal quartz in a hydrogen-free atmosphere while simultaneously applying an electric field in the Z-axis direction of the crystal. The electric field is maintained during the cool-down phase of the process.

  14. Effect of particle size in the TL response of natural quartz sensitized by high dose of gamma radiation and heat-treatments

    Directory of Open Access Journals (Sweden)

    Álvaro Barbosa de Carvalho Jr

    2010-06-01

    Full Text Available This work investigates the effect of particle size in the thermoluminescence (TL response of a quartz crystal that was initially crushed and classified into ten size fractions between 38 μm and 5 mm. Aliquots of each size fraction were sensitized with a dose of 25 kGy of γ rays and heat-treatments at 400 °C. TL glow curves of sensitized and non-sensitized samples were recorded as a function of different test-doses of γ rays. For the non-sensitized samples, the TL peak near 325 °C increases with the decrease in particle size. In the case of sensitized samples, a strong TL peak near 300 °C increases with the increase in particle size up to mean grain size equal to 304 μm. Above 304 μm, an abrupt reduction in the TL intensity is noticed for the sensitized peak. These effects are discussed in relation to the specific surface area of quartz particles and the intensity of the electron paramagnetic resonance signal of the E'1 center induced by the sensitization process.

  15. Sapphire Viewports for a Venus Probe Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed Phase 1 program will demonstrate that sapphire viewports are feasible for use in Venus probes. TvU's commercial viewport products have demonstrated that...

  16. Secondary particle emission from sapphire single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Minnebaev, K.F., E-mail: minnebaev@mail.ru [Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation); Khvostov, V.V.; Zykova, E.Yu.; Tolpin, K.A. [Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation); Colligon, J.S. [Manchester Metropolitan University, Chester Street, Manchester M1 5GD (United Kingdom); Yurasova, V.E. [Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation)

    2015-07-01

    Secondary ion emission from sapphire single crystal has been studied experimentally and by means of computer simulation. The particular oscillations of secondary ion energy spectra and two specific maxima of O{sup +} and Al{sup +} ions were observed under irradiation of (0001) sapphire face by 1 and 10 keV Ar{sup +} ions. We have explained this by the interplay of the charge exchange processes between moving particles and solids. The existence of two maxima in energy spectra of O{sup +} and Al{sup +} secondary ions can be also connected with special features of single-crystal sputtering: the low-energy peak can be formed by random sputtering and the high-energy peak from focusing collisions. In addition some similarity was found between the positions of low-energy maximum in energy spectra of Al{sup +} ions emitted from sapphire and the principal maxima of Al{sup +} ions ejected from the aluminum single crystal. This indicates a possibility to explain the presence of low-energy maximum in energy spectra of secondary ions ejecting from sapphire by emission of Al{sup +} ions from aluminum islands appearing in a number of cases on the sapphire surface due to preferential sputtering of oxygen. These different mechanisms of creating the energy spectra of ions emitted from sapphire should be taken in account.

  17. Sapphire: a better material for atomization and in situ collection of silver volatile species for atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Musil, Stanislav, E-mail: stanomusil@biomed.cas.cz; Matoušek, Tomáš; Dědina, Jiří

    2015-06-01

    Sapphire is presented as a high temperature and corrosion resistant material of an optical tube of an atomizer for volatile species of Ag generated by the reaction with NaBH{sub 4}. The modular atomizer design was employed which allowed to carry out the measurements in two modes: (i) on-line atomization and (ii) in situ collection (directly in the optical tube) by means of excess of O{sub 2} over H{sub 2} in the carrier gas during the trapping step and vice versa in the volatilization step. In comparison with quartz atomizers, the sapphire tube atomizer provides a significantly increased atomizer lifetime as well as substantially improved repeatability of the Ag in situ collection signals shapes. In situ collection of Ag in the sapphire tube atomizer was highly efficient (> 90%). Limit of detection in the on-line atomization mode and in situ collection mode, respectively, was 1.2 ng ml{sup −1} and 0.15 ng ml{sup −1}. - Highlights: • Sapphire was tested as a new material of an atomizer tube for Ag volatile species. • Two measurement modes were investigated: on-line atomization and in situ collection. • In situ collection of Ag was highly efficient (> 90%) with LOD of 0.15 ng ml{sup −1}. • No devitrification of the sapphire tube observed in the course of several months.

  18. A higher-order-mode fiber delivery for Ti:Sapphire femtosecond lasers

    DEFF Research Database (Denmark)

    Jespersen, Kim Giessmann; Le, Tuan; Grüner-Nielsen, Lars Erik

    2010-01-01

    We report the first higher-order-mode fiber with anomalous dispersion at 800nm and demonstrate its potential in femtosecond pulse delivery for Ti:Sapphire femtosecond lasers. We obtain 125fs pulses after propagating a distance of 3.6 meters in solid-silica fiber. The pulses could be further...... compressed in a quartz rod to nearly chirp-free 110fs pulses. Femtosecond pulse delivery is achieved by launching the laser output directly into the delivery fiber without any pre-chirping of the input pulse. The demonstrated pulse delivery scheme suggests scaling to >20meters for pulse delivery in harsh...

  19. Quartz crystal growth

    Science.gov (United States)

    Baughman, Richard J.

    1992-01-01

    A process for growing single crystals from an amorphous substance that can undergo phase transformation to the crystalline state in an appropriate solvent. The process is carried out in an autoclave having a lower dissolution zone and an upper crystallization zone between which a temperature differential (.DELTA.T) is maintained at all times. The apparatus loaded with the substance, solvent, and seed crystals is heated slowly maintaining a very low .DELTA.T between the warmer lower zone and cooler upper zone until the amorphous substance is transformed to the crystalline state in the lower zone. The heating rate is then increased to maintain a large .DELTA.T sufficient to increase material transport between the zones and rapid crystallization. .alpha.-Quartz single crystal can thus be made from fused quartz in caustic solvent by heating to 350.degree. C. stepwise with a .DELTA.T of 0.25.degree.-3.degree. C., increasing the .DELTA.T to about 50.degree. C. after the fused quartz has crystallized, and maintaining these conditions until crystal growth in the upper zone is completed.

  20. Method of surface treatment on sapphire substrate

    Institute of Scientific and Technical Information of China (English)

    NIU Xin-huan; LIU Yu-ling; TAN Bai-mei; HAN Li-ying; ZHANG Jian-xin

    2006-01-01

    Sapphire single crystals are widely used in many areas because of the special physic properties and important application value. As an important substrate material,stringent surface quality requirements,i.e. surface finish and flatness,are required. The use of CMP technique can produce high quality surface finishes at low cost and with fast material removal rates. The sapphire substrate surface is treated by using CMP method. According to sapphire substrate and its product properties,SiO2 sol is chosen as abrasive. The particle size is 15-25 nm and the concentration is 40%. According to the experiment results,pH value is 10.5-11.5. After polishing and cleaning the sapphire surface,the surface roughness was measured by using AFM method and the lowest value of Ra 0.1 nm was obtained. From the results,it can be seen that using such method,the optimal sapphire surface can be gotten,which is advantageous for epitaxial growth and device making-up.

  1. Pressure measurement using the R fluorescence peaks and 417 cm-1 Raman peak of an anvil in a sapphire-anvil cell

    Science.gov (United States)

    Gao, Rong; Li, Heping

    2012-06-01

    In this study, synthetic sapphire crystals were used as anvils, coupled with a metal gasket, in a Merrill-Bassett-type pressure cell (sapphire-anvil cell (SAC)). Quartz and ruby chips were compressed in the cell and used as pressure calibrators for the SAC. In the sample-anvil interface, the relationship of the frequency shifts of the R1, R2 and 417 cm-1 peaks with pressure was studied. They were constructed as new pressure calibrators. To test the applicability of the newly calibrated SAC, the Raman spectra of dolomite and calcite were measured in situ at room temperature.

  2. Trace elements in quartz shed light on sediment provenance

    Science.gov (United States)

    Ackerson, Michael R.; Tailby, Nicholas D.; Watson, E. Bruce

    2015-06-01

    Quartz is one of the most common minerals on the surface of the earth, and is a primary rock-forming mineral across the rock cycle. These two factors make quartz an obvious target for sediment provenance studies. Observations from experimental and natural samples demonstrate that the trace element content of quartz often reflects the conditions of quartz formation. When quartz is weathered from its primary crystallization setting (i.e., quartz from a granitoid) it can retain many chemical signatures of formation throughout the sedimentation processes. These geochemical signatures can be used to understand the primary source of individual quartz grains within a sediment. Here we present a case study from the Bega River catchment to demonstrate that quartz grains in sediments at the mouth of the Bega River are sourced from granitoids within the drainage basin. Data presented here also indicate that a portion of the beach sediment is also derived from either (i) sedimentary rocks within the basin or; (ii) mixing with sediments at the mouth of the river. The Bega River catchment was selected for this study because it is both small and has a well-constrained bedrock lithology, making it an ideal location to test the utility of this provenance technique. However, quartz trace element provenance has broad applications to modern and ancient sediments and can be used in lieu of, or in conjunction with, other provenance techniques to elucidate sediment transport through time.

  3. Use of Be(p,{alpha}) and Be(p,d) Reactions to Determine Be Content in Sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Franklyn, C. B. [Radiation Science Department, Necsa, PO Box 582, Pretoria 0001 (South Africa)

    2011-12-13

    Since natural coloured sapphire ({alpha}-Al{sub 2}O{sub 3}) commands a high gem stone market price there is a need for a reliable method of identifying artificially coloured sapphire that has an inherently lower value. Diffusing beryllium into sapphire at high temperatures results in a coloured stone virtually indistinguishable from a natural one. Beryllium can occur naturally in sapphire but at levels of <1 ppma. Beryllium diffused sapphire typically contains >10 ppma, which is difficult to determine in a non destructive way. It is possible to utilize nuclear reaction analysis techniques to determine the beryllium content in a macroscopically non destructive way. Kinematically ideal reactions are Be(p,{alpha}) and Be(p,d) which, for Ep = 0.5 to 0.9 MeV, exhibit distinct reaction product signatures well separated from other proton induced reactions in aluminium or oxygen. Due to the lack of comprehensive cross section data for the Be(p,{alpha}) and Be(p,d) reactions in the energy range of interest, a series of measurements were made at the Van de Graaff accelerator facility at Necsa to create a new data base. A further outcome of these measurements was a deviation in reported values for the non-Rutherfordian proton back-scatter cross section. These new data bases, which extend to Ep = 2.6MeV, can now facilitate a procedure for determining beryllium content in sapphire.

  4. Sapphire Energy - Integrated Algal Biorefinery

    Energy Technology Data Exchange (ETDEWEB)

    White, Rebecca L. [Sapphire Energy, Inc., Columbus, NM (United States). Columbus Algal Biomass Farm; Tyler, Mike [Sapphire Energy, Inc., San Diego, CA (United States)

    2015-07-22

    Sapphire Energy, Inc. (SEI) is a leader in large-scale photosynthetic algal biomass production, with a strongly cohesive research, development, and operations program. SEI takes a multidiscipline approach to integrate lab-based strain selection, cultivation and harvest and production scale, and extraction for the production of Green Crude oil, a drop in replacement for traditional crude oil.. SEI’s technical accomplishments since 2007 have produced a multifunctional platform that can address needs for fuel, feed, and other higher value products. Figure 1 outlines SEI’s commercialization process, including Green Crude production and refinement to drop in fuel replacements. The large scale algal biomass production facility, the SEI Integrated Algal Biorefinery (IABR), was built in Luna County near Columbus, New Mexico (see fig 2). The extraction unit was located at the existing SEI facility in Las Cruces, New Mexico, approximately 95 miles from the IABR. The IABR facility was constructed on time and on budget, and the extraction unit expansion to accommodate the biomass output from the IABR was completed in October 2012. The IABR facility uses open pond cultivation with a proprietary harvesting method to produce algal biomass; this biomass is then shipped to the extraction facility for conversion to Green Crude. The operation of the IABR and the extraction facilities has demonstrated the critical integration of traditional agricultural techniques with algae cultivation knowledge for algal biomass production, and the successful conversion of the biomass to Green Crude. All primary unit operations are de-risked, and at a scale suitable for process demonstration. The results are stable, reliable, and long-term cultivation of strains for year round algal biomass production. From June 2012 to November 2014, the IABR and extraction facilities produced 524 metric tons (MT) of biomass (on a dry weight basis), and 2,587 gallons of Green Crude. Additionally, the IABR

  5. Bonding of sapphire to sapphire by eutectic mixture of aluminum oxide and zirconium oxide

    Science.gov (United States)

    Deluca, J. J. (Inventor)

    1979-01-01

    An element comprising sapphire, ruby or blue sapphire can be bonded to another element of such material with a eutectic mixture of aluminum oxide and zirconium oxide. The bonding mixture may be applied in the form of a distilled water slurry or by electron beam vapor deposition. In one embodiment the eutectic is formed in situ by applying a layer of zirconium oxide and then heating the assembly to a temperature above the eutectic temperature and below the melting point of the material from which the elements are formed. The formation of a sapphire rubidium maser cell utilizing eutectic bonding is shown.

  6. A comparative study on methods to structure sapphire

    NARCIS (Netherlands)

    Crunteanu, A.; Hoffmann, P.; Pollnau, M.; Buchal, C.

    2003-01-01

    Ti:sapphire is an attractive material for applications as a tunable or short-pulse laser and as a broadband light source in low-coherence interferometry. We investigated several methods to fabricate rib structures in sapphire that can induce channel waveguiding in Ti:sapphire planar waveguides. Thes

  7. Stability of trapped charges in sapphires and alumina ceramics: Evaluation by secondary electron emission

    Science.gov (United States)

    Zarbout, K.; Si Ahmed, A.; Moya, G.; Bernardini, J.; Goeuriot, D.; Kallel, A.

    2008-03-01

    The stability of trapped charges in sapphires and alumina ceramics is characterized via an experimental parameter expressing the variation of the secondary electron emission yield between two electron injections performed in a scanning electron microscope. Two types of sapphires and polycrystalline alumina, which differ mainly by their impurity content, are investigated in the temperature range 300-663K. The stable trapping behavior in sapphires is attributed to trapping in different defects, whose nature depends on the purity level. In alumina ceramics, the ability to trap charges in a stable way is stronger in samples of high impurity content. In the low impurity samples, stable trapping is promoted when the grain diameter decreases, whereas the reverse is observed in high impurity materials. These behaviors can stem from a gettering effect occurring during sintering. The strong dependence of the variation of the secondary electron emission yield on the grain diameter and impurities enables a scaling of the stable trapping ability of alumina materials.

  8. Quartz Crystal Microbalance Data

    Energy Technology Data Exchange (ETDEWEB)

    Baxamusa, S H

    2011-11-16

    We are using a Qpod quartz crystal microbalance (manufactured by Inficon) for use as a low-volume non-volatile residue analysis tool. Inficon has agreed to help troubleshoot some of our measurements and are requesting to view some sample data, which are attached. The basic principle of an NVR analysis is to evaporate a known volume of solvent, and weigh the remaining residue to determine the purity of the solvent. A typical NVR analysis uses 60 g of solvent and can measure residue with an accuracy of +/- 0.01 mg. The detection limit is thus (0.01 mg)/(60 g) = 0.17 ppm. We are attempting to use a quartz crystal microbalance (QCM) to make a similar measurement. The attached data show the response of the QCM as a 5-20 mg drop of solvent evaporates on its surface. The change in mass registered by the QCM after the drop evaporates is the residue that deposits on the crystal. On some measurements, the change in mass in less than zero, which is aphysical since the drop will leave behind {>=}0 mass of residue. The vendor, Inficon, has agreed to look at these data as a means to help troubleshoot the cause.

  9. Sapphire and other dielectric waveguide devices

    NARCIS (Netherlands)

    Pollnau, Markus

    2008-01-01

    Different fabrication methods have been explored successfully and surface and buried channel waveguide lasers have been demonstrated in Ti:sapphire for the first time. Since the propagation losses of these first-generation waveguides are still rather high, substantial improvement is required in orde

  10. Sapphire and other dielectric waveguide devices

    NARCIS (Netherlands)

    Pollnau, Markus

    Different fabrication methods have been explored successfully and surface and buried channel waveguide lasers have been demonstrated in Ti:sapphire for the first time. Since the propagation losses of these first-generation waveguides are still rather high, substantial improvement is required in

  11. Advanced thin dicing blade for sapphire substrate

    Directory of Open Access Journals (Sweden)

    Koji Matsumaru, Atsushi Takata and Kozo Ishizaki

    2005-01-01

    Full Text Available Advanced thin dicing blades for cutting sapphire were fabricated and evaluated for cutting performance with respect to dicing blade wear and meandering of cutting lines. Three kinds of different commercial blades were used to compare the cutting performance. These blades had the same thickness and the same diamond grain size. The matrix material of one dicing blade was nickel–phosphorus alloy and two other were a vitric material. Newly developed dicing blades consisted of a vitric material with pore. A dicing machine was used for cutting sapphire. Turning velocity, cutting depth and feeding rate were 20,000 min−1, 200 μm and 1 mm s−1, respectivity. Cutting directions were 110 and 010. All blades could cut 1000 mm and more in the 110 direction. On the other hand, commercial dicing blades generated meandering lines and were broken only by 50 mm of cutting length in 010 direction. Fabricated blade can cut 1000 mm and more in 010 direction. The wear of fabricated dicing blade was the largest in the dicing blades. Although cutting performance of commercial dicing blades depended on the sapphire orientation, that of fabricated blade was independent of the sapphire orientation. It has been confirmed that the fabricated dicing blade was kept a cutting ability by flash diamonds on the dicing blade surface, which were created by wear of blade during cutting sapphire. Low cutting ability of commercial blades increased cutting force between with increase of cutting length. The increased cutting force produced to bend a blade and cutting lines, and finally a fracture of blade.

  12. Thermal quenching of thermoluminescence in quartz samples of various origin

    Energy Technology Data Exchange (ETDEWEB)

    Subedi, B. [Aristotle University of Thessaloniki, Nuclear Physics Laboratory, 54124-Thessaloniki (Greece); Oniya, E. [Archaeometry Laboratory, Cultural and Educational Technology Institute (C.E.T.I.), R.C. ' Athena' , Tsimiski 58, 67100 Xanthi (Greece); Physics and Electronics Department, Adekunle Ajasin University, PMB 01, Akungba Akoko (Nigeria); Polymeris, G.S. [ISIK University, Physics Department, Faculty of Science and Arts, 34980-Sile, Istanbul (Turkey); Afouxenidis, D.; Tsirliganis, N.C. [Archaeometry Laboratory, Cultural and Educational Technology Institute (C.E.T.I.), R.C. ' Athena' , Tsimiski 58, 67100 Xanthi (Greece); Kitis, G., E-mail: gkitis@auth.g [Aristotle University of Thessaloniki, Nuclear Physics Laboratory, 54124-Thessaloniki (Greece)

    2011-03-15

    The effect of thermal quenching stands among the most important properties in the thermoluminescence (TL) of quartz on which many applications of TL are based. Since the quartz samples used in various applications are all of different origin it is useful to investigate whether the values of the thermal quenching parameters, i.e. the activation energy for thermal quenching W and a parameter C which describes the ratio of non-radiative to radiative luminescence transitions, evaluated mainly in specific quartz samples can be extrapolated to quartz samples of unknown origin as well as to quartz samples which are annealed at high temperatures. In the present work the TL glow curve of a series of un-annealed and annealed natural and synthetic quartz samples were studied as a function of the heating rate between 0.25 K/s and 16 K/s. Using an indirect fitting method it was found that the thermal quenching parameters W and C in most of the quartz samples are very similar to the values accepted in the literature. Furthermore, in some cases the thermal quenching parameters W and C are not the same for all TL glow-peaks in the same glow-curve. Finally, the strong external treatment of annealing the quartz samples at very high temperature can also influence at least one of the thermal quenching parameters.

  13. Quartz resonator processing system

    Science.gov (United States)

    Peters, Roswell D. M.

    1983-01-01

    Disclosed is a single chamber ultra-high vacuum processing system for the oduction of hermetically sealed quartz resonators wherein electrode metallization and sealing are carried out along with cleaning and bake-out without any air exposure between the processing steps. The system includes a common vacuum chamber in which is located a rotatable wheel-like member which is adapted to move a plurality of individual component sets of a flat pack resonator unit past discretely located processing stations in said chamber whereupon electrode deposition takes place followed by the placement of ceramic covers over a frame containing a resonator element and then to a sealing stage where a pair of hydraulic rams including heating elements effect a metallized bonding of the covers to the frame.

  14. Pulsed modification of germanium films on silicon, sapphire, and quartz substrates: Structure and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Novikov, H. A.; Batalov, R. I., E-mail: batalov@kfti.knc.ru; Bayazitov, R. M.; Faizrakhmanov, I. A.; Lyadov, N. M.; Shustov, V. A. [Russian Academy of Sciences, Zavoiskii Physical Technical Institute, Kazan Scientific Center (Russian Federation); Galkin, K. N.; Galkin, N. G.; Chernev, I. M. [Russian Academy of Sciences, Institute of Automation and Control Processes, Far-East Branch (Russian Federation); Ivlev, G. D.; Prokop’ev, S. L.; Gaiduk, P. I. [Belarussian State University (Belarus)

    2015-06-15

    The structural and optical properties of thin Ge films deposited onto semiconducting and insulating substrates and modified by pulsed laser radiation are studied. The films are deposited by the sputtering of a Ge target with a low-energy Xe{sup +} ion beam. Crystallization of the films is conducted by their exposure to nanosecond ruby laser radiation pulses (λ = 0.694 μm) with the energy density W = 0.2−1.4 J cm{sup −2}. During pulsed laser treatment, the irradiated area is probed with quasi-cw (quasi-continuous-wave) laser radiation (λ = 0.532 and 1.064 μm), with the reflectance recorded R(t). Experimental data on the lifetime of the Ge melt are compared with the results of calculation, and good agreement between them is demonstrated. Through the use of a number of techniques, the dependences of the composition of the films, their crystal structure, the level of strains, and the reflectance and transmittance on the conditions of deposition and annealing are established.

  15. Development of a rubber elongation factor, surface-imprinted polymer-quartz crystal microbalance sensor, for quantitative determination of Hev b1 rubber latex allergens present in natural rubber latex products.

    Science.gov (United States)

    Sontimuang, Chonlatid; Suedee, Roongnapa; Canyuk, Bhutorn; Phadoongsombut, Narubodee; Dickert, Franz L

    2011-02-21

    Molecularly imprinted polymers (MIPs) for screening to detect rubber latex allergens (Hev b1) in natural rubber based products were designed as artificial recognition polymeric materials coated onto a quartz crystal microbalance (QCM). The polymers were prepared using a stamp imprinting procedure after mixing optimum amounts of methacrylic acid-vinylpyrrolidone-dihydroxyethylene bisacrylamide and Hev b1 latex allergen proteins, obtained from rubber gloves. QCM measurements showed that the resulting polymer layers after removal of the proteins used in their preparation could incorporate structures and features down to nanometer scale of protein templates into the imprinted polymer much better than a non-specific control polymer under controlled sensor conditions and an optimized polymerization process. This selective polymer but not the non-selective polymer clearly distinguished between the latex allergen Hev b1 and proteins such as lysozyme, ovalbumin and bovine serum albumin, with a selectivity factor of from 2 to 4, and the response of the rubber elongation factors by an astonishing factor of 12. The imprinted cavities recognized specific binding sites and could distinguish among related hevein latex allergenic proteins isolated from fresh natural rubber latex; Hev b1, Hev b2, and Hev b3 with a selectivity factor of from 4 to 6. The different QCM measurements obtained presumably reflected slightly different conformations and affinities to the MIP binding sites. The sensor layers selectively adsorbed Hev b1 within minutes in amounts ranging from 10 to 1500 μg L⁻¹ and with a detection limit of 1 μg L⁻¹. This work has demonstrated that this new sensor provides a fast and reliable response to natural rubber latex protein, even after being extracted from the matrix of rubber gloves.

  16. Spontaneous formation of GaN/AlN core-shell nanowires on sapphire by hydride vapor phase epitaxy

    Science.gov (United States)

    Trassoudaine, Agnès; Roche, Elissa; Bougerol, Catherine; André, Yamina; Avit, Geoffrey; Monier, Guillaume; Ramdani, Mohammed Réda; Gil, Evelyne; Castelluci, Dominique; Dubrovskii, Vladimir G.

    2016-11-01

    Spontaneous GaN/AlN core-shell nanowires with high crystal quality were synthesized on sapphire substrates by vapor-liquid-solid hydride vapor phase epitaxy (VLS-HVPE) without any voluntary aluminum source. Deposition of aluminum is difficult to achieve in this growth technique which uses metal-chloride gaseous precursors: the strong interaction between the AlCl gaseous molecules and the quartz reactor yields a huge parasitic nucleation on the walls of the reactor upstream the substrate. We open up an innovative method to produce GaN/AlN structures by HVPE, thanks to aluminum etching from the sapphire substrate followed by redeposition onto the sidewalls of the GaN core. The paper presents the structural characterization of GaN/AlN core-shell nanowires, speculates on the growth mechanism and discusses a model which describes this unexpected behavior.

  17. Surface modification of sapphire by ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    McHargue, C.J.

    1998-11-01

    The range of microstructures and properties of sapphire (single crystalline Al{sub 2}O{sub 3}) that are produced by ion implantation are discussed with respect to the implantation parameters of ion species, fluence, irradiation temperature and the orientation of the ion beam relative to crystallographic axes. The microstructure of implanted sapphire may be crystalline with varying concentrations of defects or it may be amorphous perhaps with short-range order. At moderate to high fluences, implanted metallic ions often coalesce into pure metallic colloids and gas ions form bubbles. Many of the implanted microstructural features have been identified from studies using transmission electron microscopy (TEM), optical spectroscopy, Moessbauer spectroscopy, and Rutherford backscattering-channeling. The chemical, mechanical, and physical properties reflect the microstructures.

  18. The growth of sapphire single crystals

    Directory of Open Access Journals (Sweden)

    STEVAN DJURIC

    2001-06-01

    Full Text Available Sapphire (Al2O3 single crystals were grown by the Czochralski technique both in air and argon atmospheres. The conditions for growing sapphire single crystals were calculated by using a combination of Reynolds and Grashof numbers. Acritical crystal diameter dc = 20 mm and the critical rate of rotation wc = 20 rpm were calculated from the hydrodynamics of the melt. The value of the rate of crystal growth was experimentally found to be 3.5 mm/h. According to our previous experiments, it was confirmed that three hours exposures to conc. H3PO4 at 593 K was suitable for chemical polishing. Also, three hours exposure to conc.H3PO4 at 523 K was found to be a suitable etching solution. The lattice parameters a = 0.47573 nm and c = 1.29893 nm were determined by X-ray powder diffraction. The obtained results are discussed and compared with published data.

  19. Electrochemical Quartz Crystal Nanobalance

    Science.gov (United States)

    Inzelt, György

    The method of piezoelectric microgravimetry (nanogravimetry) using an electrochemical quartz crystal microbalance (EQCM) or nanobalance (EQCN) can be considered as a novel and much more sensitive version of electrogravimetry. The EQCN technique has become a widely used technique in several areas of electrochemistry, electroanalytical chemistry, bioelectrochemistry, etc. [1-10]. Obviously, mass changes occurring during adsorption, sorption, electrosorption, electrodeposition, or spontaneous deposition can be followed, which is very helpful for the elucidation of reaction mechanism via identification of the species accumulated on the surface. These investigations include metal and alloy deposition, underpotential deposition, electroplating, synthesis of conducting polymers by electropolymerization, adsorption of biologically active materials, and analytical determination of small ions and biomolecules. Of course, the opposite processes, i.e., spontaneous dissolution, electrodissolution, corrosion, can also be studied. Electrochemical oscillations, in which the formation and oxidation of chemisorbed molecular fragments play a determining role, have been studied, too. The majority of the investigations have been devoted to ion and solvent transport associated with the redox transformations of electrochemically active polymers. Similar studies have been carried out regarding polynuclear surface layers such as metal hexacyanometalates as well as inorganic and organic microcrystals of different compositions.

  20. Force chain forming quartz in an ultramylonite

    Science.gov (United States)

    Kilian, Rüdiger; Morales, Luiz F. G.; Peters, Max

    2014-05-01

    Polymineralic ultramylonites often show microstructures indicative of grain size sensitive creep with dissolution precipitation or diffusion accommodated grain boundary sliding. Typically phases show an anticorrelated distribution, the grain size is small and a crystallographic preferred orientation is absent. The latter observation is usually thought to originate from rigid body rotation of grains because flow dominated by diffusion creep operates at differential stresses, which are too low to activate crystal-plastic mechanisms. Here, we present quartz texture measurements from a natural ultramylonite, deformed under upper amphibolite facies conditions from the Nordmannvik Nappe, Upper Allochton of the Norwegian Caledonides. The ultramylonite has a mean grain size crystal-plastic processes. Alternative texture forming processes (e.g. growth textures) are also discussed. The texture in the foliation parallel clusters is thought to be an inherited texture from lower strain stages in the ultramylonite, as it is mostly present in the least deformed parts of the ultramylonite. However, we suggest that the texture formed in the foliation oblique clusters is related to a dynamic formation of force chains between quartz grains, where differential stresses become high enough for plastic yielding. The presence of force chains questions whether ultramylonites necessarily need to possess a linear viscous rheology, even if microstructures would indicate a diffusion creep mechanism. Pennacchioni G., Menegon L., Leiss B., Nestola F., Bromiley G., 2010: Development of crystallographic preferred orientation and microstructure during plastic deformation of natural coarse?grained quartz veins. Journal of Geophysical Research, Vol. 115, B12405

  1. Identification of color development potential of quartz by Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Alkmim, Danielle G.; Lameiras, Fernando S.; Almeida, Frederico O.T., E-mail: alkmia@yahoo.com.br, E-mail: fsl@cdtn.br [Centro e Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horionte, MG (Brazil)

    2013-07-01

    Colorless quartz is usually exposed to ionizing radiation (gamma rays or high energy electron beams) to acquire different colors for jewelry. Color development is due to the presence of traces of some elements such as aluminum, iron, hydrogen, lithium, or sodium. Most quartz crystals are extracted colorless from nature and it is necessary to separate those that can develop colors from those that cannot. Irradiation tests can be used to accomplish this separation, but they take a long time. Infrared signature of colorless quartz can also be used. However, infrared spectroscopy is quite expensive, especially when using portable devices. Raman spectroscopy is now available as an inexpensive and portable technique that could provide identification of the samples of colorless quartz still in the field, facilitating the prediction for their economic exploitation. In addition, Raman spectroscopy usually requires a minimum or no sample preparation. This paper presents an investigation of the feasibility of using Raman spectroscopy as a substitute for infrared spectroscopy to predict the potential for color development of quartz. A band at 3595 cm{sup -1} in the Raman shift spectrum was observed only along the c axis of a prasiolite excited by a high power 514 nm laser. This band was not observed in quartz samples that do not develop color after irradiation. Further studies are required to identify the potential for color development by Raman spectroscopy of other types of colorless quartz. (author)

  2. Photonic detection and characterization of DNA using sapphire microspheres

    OpenAIRE

    Serpengüzel, Ali; Murib, Mohammed Sharif; Yeap, Weng-Siang; Martens, Daan; Bienstman, Peter; De Ceuninck, Ward; van Grinsven, Bart; Schoening, Michael J.; Michiels, Luc; Haenen, Ken; Ameloot, Marcel; Wagner, Patrick

    2014-01-01

    A microcavity-based deoxyribonucleic acid (DNA) optical biosensor is demonstrated for the first time using synthetic sapphire for the optical cavity. Transmitted and elastic scattering intensity at 1510 nm are analyzed from a sapphire microsphere (radius 500 mu m, refractive index 1.77) on an optical fiber half coupler. The 0.43 nm angular mode spacing of the resonances correlates well with the optical size of the sapphire sphere. Probe DNA consisting of a 36-mer fragment was covalently immob...

  3. Growth and characterisation of epitaxially ordered zinc aluminate domains on c-sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Grabowska, J.; Rajendra Kumar, R.T. [School of Physical Sciences/National Centre for Plasma Science and Technology, Dublin City University (Ireland); McGlynn, E. [School of Physical Sciences/National Centre for Plasma Science and Technology, Dublin City University (Ireland)], E-mail: enda.mcglynn@dcu.ie; Nanda, K.K. [School of Physical Sciences/National Centre for Plasma Science and Technology, Dublin City University (Ireland); Newcomb, S.B. [Glebe Scientific Ltd., Newport, Co. Tipperary (Ireland); McNally, P.J.; O' Reilly, L. [School of Electronic Engineering/Research Institute for Networks and Communications Engineering, Dublin City University (Ireland); Mosnier, J.-P.; Henry, M.O. [School of Physical Sciences/National Centre for Plasma Science and Technology, Dublin City University (Ireland)

    2008-02-29

    Epitaxially ordered zinc aluminate domains with sub-micron dimensions are formed on bare c-sapphire substrates using a vapour phase method (with vapour generated by carbothermal reduction of ZnO) at various temperatures and growth durations. A zinc aluminate (ZnAl{sub 2}O{sub 4}) layer is formed by reaction of the source materials (Zn and O) with the substrate. We observe crystallites with a well-defined epitaxial relationship on the sapphire substrate in addition to polycrystalline material. The epitaxially oriented deposit displays the form of characteristically twinned (singly or multiply) grains of sub-micron dimensions with three variants, consistent with the c-sapphire substrate symmetry. Scanning electron microscopy and transmission electron microscopy studies show that the formation of these grains is associated with the presence of extended defects in the sapphire substrate. Epitaxially ordered grains formed at higher temperatures show a change in the nature of the twin boundaries and epitaxial relations as a function of growth time, attributed to the effects of annealing during growth.

  4. Vanadium-rich ruby and sapphire within Mogok Gemfield, Myanmar: implications for gem color and genesis

    Science.gov (United States)

    Zaw, Khin; Sutherland, Lin; Yui, Tzen-Fu; Meffre, Sebastien; Thu, Kyaw

    2015-01-01

    Rubies and sapphires are of both scientific and commercial interest. These gemstones are corundum colored by transition elements within the alumina crystal lattice: Cr3+ yields red in ruby and Fe2+, Fe3+, and Ti4+ ionic interactions color sapphires. A minor ion, V3+ induces slate to purple colors and color change in some sapphires, but its role in coloring rubies remains enigmatic. Trace element and oxygen isotope composition provide genetic signatures for natural corundum and assist geographic typing. Here, we show that V can dominate chromophore contents in Mogok ruby suites. This raises implications for their color quality, enhancement treatments, geographic origin, exploration and exploitation and their comparison with rubies elsewhere. Precise LA-ICP-MS analysis of ruby and sapphire from Mogok placer and in situ deposits reveal that V can exceed 5,000 ppm, giving V/Cr, V/Fe and V/Ti ratios up to 26, 78, and 97 respectively. Such values significantly exceed those found elsewhere suggesting a localized geological control on V-rich ruby distribution. Our results demonstrate that detailed geochemical studies of ruby suites reveal that V is a potential ruby tracer, encourage comparisons of V/Cr-variation between ruby suites and widen the scope for geographic typing and genesis of ruby. This will allow more precise comparison of Asian and other ruby fields and assist confirmation of Mogok sources for rubies in historical and contemporary gems and jewelry.

  5. Sapphire Multiple Filament and Large Plate Growth Processes

    Science.gov (United States)

    1972-10-01

    for sapphire filaments is scrap white verneuil -grown sapphire boules. These boules are processed here at Tyco to achieve the proper mesh size...entrapped liquid freeze, they shrink, resulting in voids. Raw material for our growth process is provided by use of scap verneuil sapphire boules. In...J ;~ ;t" ,, ,, .. ::~ ,:~~\\i : i .<’\\ :1 ’ r .,l,, .. ’ ... :,J_ ’ ’~~ .. ;~ 1-.. i d;·, AFML-TR -7---190 1;).-- SAPPHIRE MULTIPLE

  6. REINFORCEMENT OF NICKEL CHROMIUM ALLOYS WITH SAPPHIRE WHISKERS.

    Science.gov (United States)

    SAPPHIRE, COMPOSITE MATERIALS, CERAMIC FIBERS , CERAMIC FIBERS , TITANIUM COMPOUNDS, ZIRCONIUM COMPOUNDS, HYDRIDES, ADDITIVES, CHROMIUM ALLOYS, FIBER METALLURGY, IRON COMPOUNDS, ENCAPSULATION, DENSITY, SURFACE TENSION.

  7. Structure of the Dislocation in Sapphire

    DEFF Research Database (Denmark)

    Bilde-Sørensen, Jørgen; Thölen, A. R.; Gooch, D. J.;

    1976-01-01

    of ⅓ 01 0 and are separated by two identical faults. The distance between two partials is in the range 75-135 Å, corresponding to a fault energy of 320±60 mJ/m2. Perfect 01 0 dislocations have also been observed. These dislocations exhibited either one or two peaks when imaged in the (03 0) reflection......Experimental evidence of the existence of 01 0 dislocations in the {2 0} prism planes in sapphire has been obtained by transmission electron microscopy. By the weak-beam technique it has been shown that the 01 0 dislocations may dissociate into three partials. The partials all have a Burgers vector...

  8. Amorphization of α-Quartz under Irradiation

    Science.gov (United States)

    Douillard, L.; Duraud, J. P.

    1996-12-01

    The course of radiation induced damage produced in α-quartz by neutrons, ions, electrons or photons — commonly known as metamictization — has been re-analyzed by careful comparison of available experimental data. Specific interest was devoted to confront experimental metamict state features with current structural models. It comes out that the metamict state of irradiated quartz should exhibit some structural characteristics of the modulated structure proposed for vitreous silica. The metamictization process is consistent with a structural relaxation process of a highly defective quartz matrix. According to this new point defect analysis, structural relaxation should be triggered by a critical concentration of oxygen vacancy point defects likely to significantly lower the connectivity of the SiO{2} network. Various experimental results are interpreted by incorporating the influence of the SiO{2} crystalline polymorph and the influence of the nature of the irradiating particle to the point defect model. Nous avons étudié les modifications de propriétés et de structures de monocristaux de quartz α, consécutives à une irradiation sévère par des neutrons, des ions, des électrons ou des photons. Ce phénomène d'altération du quartz sous irradiation porte le nom de métamictisation. Notre travail exploite les recoupements de travaux antérieurs. Une attention particulière a été portée à la confrontation entre les données structurales expérimentales disponibles sur l'état métamicte du quartz et les modèles structuraux proposés. L'état métamicte du quartz présente ainsi les caractéristiques structurales du modèle de structure modulée, avancé pour décrire la structure de la silice thermique. Le mécanisme de métamictisation procéderait par relaxation de la matrice cristalline fortement endommagée. Ce phénomène de relaxation serait initié par l'apparition de concentration critique de défauts ponctuels de type lacunes d

  9. Atomic fountain clock with very high frequency stability employing a pulse-tube-cryocooled sapphire oscillator.

    Science.gov (United States)

    Takamizawa, Akifumi; Yanagimachi, Shinya; Tanabe, Takehiko; Hagimoto, Ken; Hirano, Iku; Watabe, Ken-ichi; Ikegami, Takeshi; Hartnett, John G

    2014-09-01

    The frequency stability of an atomic fountain clock was significantly improved by employing an ultra-stable local oscillator and increasing the number of atoms detected after the Ramsey interrogation, resulting in a measured Allan deviation of 8.3 × 10(-14)τ(-1/2)). A cryogenic sapphire oscillator using an ultra-low-vibration pulse-tube cryocooler and cryostat, without the need for refilling with liquid helium, was applied as a local oscillator and a frequency reference. High atom number was achieved by the high power of the cooling laser beams and optical pumping to the Zeeman sublevel m(F) = 0 employed for a frequency measurement, although vapor-loaded optical molasses with the simple (001) configuration was used for the atomic fountain clock. The resulting stability is not limited by the Dick effect as it is when a BVA quartz oscillator is used as the local oscillator. The stability reached the quantum projection noise limit to within 11%. Using a combination of a cryocooled sapphire oscillator and techniques to enhance the atom number, the frequency stability of any atomic fountain clock, already established as primary frequency standard, may be improved without opening its vacuum chamber.

  10. Materials processing by use of a Ti:Sapphire laser with automatically-adjustable pulse duration

    Science.gov (United States)

    Kamata, M.; Imahoko, T.; Ozono, K.; Obara, M.

    We have developed an automatic pulsewidth-adjustable femtosecond Ti:Sapphire laser system that can generate an output of 50 fs-1 ps in duration, and sub-mJ/pulse at a repetition rate of 1 kpps. The automatic pulse compressor enables one to control the pulsewidth in the range of 50 fs-1 ps by use of a personal computer (PC). The compressor can change the distance in-between and the tilt angle of the grating pairs by use of two stepping motors and two piezo-electric transducer(PZT) driven actuators, respectively. Both are controlled by a PC. Therefore, not only control of the pulsewidth, but also of the optical chirp becomes easy. By use of this femtosecond laser system, we fabricated a waveguide in fused quartz. The numerical aperture is chosen to 0.007 to loosely focus the femtosecond laser. The fabricated waveguides are well controllable by the incident laser pulsewidth. We also demonstrated the ablation processing of hydroxyapatite (Ca10(PO4)6(OH)2), which is a key component of human tooth and human bone for orthopedics and dentistry. With pulsewidth tunable output from 50 fs through 2 ps at 1 kpps, the chemical content of calcium and phosphorus is kept unchanged before and after 50-fs-2-ps laser ablation. We also demonstrated the precise ablation processing of human tooth enamel with 2 ps Ti:Sapphire laser.

  11. Kinetics of the coesite to quartz transformation

    Science.gov (United States)

    Mosenfelder, J.L.; Bohlen, S.R.

    1997-01-01

    The survival of coesite in ultrahigh-pressure (UHP) rocks has important implications for the exhumation of subducted crustal rocks. We have conducted experiments to study the mechanism and rate of the coesite ??? quartz transformation using polycrystalline coesite aggregates, fabricated by devitrifying silica glass cylinders containing 2850H/106 Si at 1000??C and 3.6 GPa for 24h. Conditions were adjusted following synthesis to transform the samples at 700-1000??C at pressures 190-410 MPa below the quartz-coesite equilibrium boundary. Reaction proceeds via grain-boundary nucleation and interface-controlled growth, with characteristic reaction textures remarkably similar to those seen in natural UHP rocks. We infer that the experimental reaction mechanism is identical to that in nature, a prerequisite for reliable extrapolation of the rate data. Growth rates obtained by direct measurement differ by up to two orders of magnitude from those estimated by fitting a rate equation to the transformation-time data. Fitting the rates to Turnbull's equation for growth therefore yields two distinct sets of parameters with similar activation energies (242 or 269 kJ/mol) but significantly different pre-exponential constants. Extrapolation based on either set of growth rates suggests that coesite should not be preserved on geologic time scales if it reaches the quartz stability field at temperatures above 375-400??C. The survival of coesite has previously been linked to its inclusion in strong phases, such as garnet, that can sustain a high internal pressure during decompression. Other factors that may play a crucial role in preservation are low fluid availability - possibly even less than that of our nominally "dry" experiments - and the development of transformation stress, which inhibits nucleation and growth. These issues are discussed in the context of our experiments as well as recent observations from natural rocks. ?? 1997 Elsevier Science B.V.

  12. Calorimetric thermobarometry of experimentally shocked quartz

    Science.gov (United States)

    Ocker, Katherine D.; Gooding, James L.; Hoerz, Friedrich

    1994-01-01

    Structural damage in experimentally shock-metamorphosed, granular quartz is quantitatively measurable by differential scanning calorimetry (DSC). Shock-induced loss of crystallinity is witnessed by disappearance of the alpha/beta phase transformation and evolution of a broad endoenthalpic strain peak at 650-900 K. The strain-energy peak grows rapidly at less than 10 GPa but declines with increasing shock pressure; it approaches zero at 32 GPa where vitrification is extensive. Effects of grain size and post-shock thermal history must be better understood before calorimetric thermobarometry of naturally shocked samples becomes possible.

  13. Double Sided Si(Ge)/Sapphire/III-Nitride Hybrid Structure

    Science.gov (United States)

    Park, Yeonjoon (Inventor); Choi, Sang Hyouk (Inventor)

    2016-01-01

    One aspect of the present invention is a double sided hybrid crystal structure including a trigonal Sapphire wafer containing a (0001) C-plane and having front and rear sides. The Sapphire wafer is substantially transparent to light in the visible and infrared spectra, and also provides insulation with respect to electromagnetic radio frequency noise. A layer of crystalline Si material having a cubic diamond structure aligned with the cubic direction on the (0001) C-plane and strained as rhombohedron to thereby enable continuous integration of a selected (SiGe) device onto the rear side of the Sapphire wafer. The double sided hybrid crystal structure further includes an integrated III-Nitride crystalline layer on the front side of the Sapphire wafer that enables continuous integration of a selected III-Nitride device on the front side of the Sapphire wafer.

  14. Direct measurement of asperity contact growth in quartz at hydrothermal conditions

    Science.gov (United States)

    Beeler, Nicholas M.; Hickman, Stephen H.

    2015-01-01

    Earthquake recurrence requires interseismic fault restrengthening which results from solid state deformation in room-temperature friction and indentation experiments. In contrast exhumed fault zones show solution-transport processes such as pressure solution and contact overgrowths influence fault zone properties . In the absence of fluid flow, overgrowths are driven by gradients in surface curvature where material is dissolved, diffuses, and precipitates at the contact without convergence normal to the contact. To determine the rate of overgrowth for quartz, we conducted single contact experiments in an externally heated pressure vessel. Convergence was continuously monitored using reflected-light interferometry through a long-working-distance microscope. Contact normal force was constant with an initial effective normal stress of 1.7 MPa, temperature was between 350 and 530{degree sign}C, and water pressure was constant at 150 MPa. Two control experiments were conducted: one dry at 425{degree sign}C and one bi-material (sapphire) at 425{degree sign}C and 150 MPa water pressure. No contact growth or convergence was observed in the controls. For wet single-phase contacts, growth was initially rapid and then decreased with time. No convergence was observed. Fluid inclusions indicate that the contact is not uniformly wetted. The contact is bounded by small regions of high aperture, reflecting local free-face dissolution as the source for the overgrowth. The apparent activation energy is ~125 kJ/mol. Extrapolation predicts rates of contact area increase orders of magnitude faster than in dry, room-temperature and hydrothermal friction experiments, suggesting that natural strength recovery near the base of the seismogenic zone could be dominated by contact overgrowth.

  15. Water weakening in experimentally deformed milky quartz single crystals

    Science.gov (United States)

    Stunitz, H.; Thust, A.; Kilian, R.; Heilbronner, R.; Behrens, H.; Tarantola, A.; Fitz Gerald, J. D.

    2015-12-01

    Natural single crystals of quartz have been experimentally deformed in two orientations: (1) normal to one prism-plane, (2) In O+ orientation at temperatures of 900 and 1000°C, pressures of 1.0 and 1.5 GPa, and strain rates of ~1 x 10-6s-1. The starting material is milky quartz, consisting of dry quartz (H2O contents of recycling of H2O between FI´s, dislocation generation at very small fluid inclusions, incorporation of structurally bound H into dislocation cores, and release of H2O from dislocations back into FI´s during recovery. Cracking and crack healing play an important role in the recycling process and imply a close interrelationship between brittle and crystal plastic deformation. The H2O weakening by this process is of a disequilibrium nature and thus depends on the amount of H2O available.

  16. Electromodulated absorption in smoky quartz

    NARCIS (Netherlands)

    Brom, W.E. van den; Volger, J.

    1974-01-01

    The optical absorption coefficient of “smoky” quartz (containing aluminium) can be modulated by applying an electric field. The effect saturates at high fields and low temperatures and reaches a maximum at 535 nm. The results are discussed in terms of a model consisting of a colour centre, dipolar i

  17. Chemical etching of deformation sub-structures in quartz

    Science.gov (United States)

    Wegner, M. W.; Christie, J. M.

    1983-02-01

    Chemical etching of dislocations has been studied in natural and synthetic quartz single crystals, in deformed synthetic quartz and in naturally and experimentally deformed quartzites. The ability of different etchants to produce polished or preferentially etched surfaces on quartz is described. Dislocation etching was achieved on all crystal planes examined by using a saturated solution of ammonium bifluoride as the etchant. Appropriate etching times were determined for etching quartzites for grain size, subgrain boundaries, deformation lamellae, dislocations and twins. Growth and polished surfaces of synthetic single crystal quartz were similarly etched and dislocation etch pits, characteristic of various orientations were found. The use of ammonium bifluoride proved to be expecially advantageous for the basal plane, producing a polished surface with etch pits, suitable for dislocation etch pit counting. “Double” etch pits have been found on Dauphiné twin boundaries on the basal plane and the first order prism, using this etchant. Slip lines and deformation bands were suitably etched on deformed synthetic crystal surfaces for identification of the slip planes. Other acidic etchants have been explored and their application to the study of deformation structures in quartz crystals is discussed.

  18. Rain Erosion Behavior of Silicon Dioxide Films Prepared on Sapphire

    Institute of Scientific and Technical Information of China (English)

    Liping FENG; Zhengtang LIU; Wenting LIU

    2005-01-01

    Silicon dioxide (SiO2) films were prepared on sapphire (α-Al2O3) by radio frequency magnetron reactive sputtering in order to in crease both transmission and rain erosion resistant performance of infrared domes of sapphire. Composition and structure of SiO2 films were analyzed by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD),respectively. The transmittance of uncoated and coated sapphire was measured using a Fourier transform infrared(FTIR) spectrometer. Rain erosion tests of the uncoated and coated sapphire were performed at 211 m/s impact velocity with an exposure time ranging from 1 to 8 min on a whirling arm rig. Results show that the deposited films can greatly increase the transmission of sapphire in mid-wave IR. After rain erosion test, decreases in normalized transmission were less than 1% for designed SiO2 films and the SiO2 coating was strongly bonded to the sapphire substrate. In addition, sapphires coated with SiO2 films had a higher transmittance than uncoated ones after rain erosion.

  19. Effect of Propellant Combustion on Sapphire

    Directory of Open Access Journals (Sweden)

    Mark L. Bundy

    2000-10-01

    Full Text Available Sapphire (Al2O3 is the window material of choice for laser beam transmission into the combustion chamber of laser-ignited guns. To evaluate the long-term effects of propellant combustion on an Al/sub 2/O/sub 3/ laser window, it is important to know the window temperature during firing. This paper presents temperature data on an Al/sub 2/O/sub 3/ sample located in the breech face of the gun where the laser window would be in a laser-ignited 155 mm(M199 cannon. Al/sub 2/O/sub 3/ sample is a substrate material of a commercially sold thin-film thermocouple, and is therefore thermally, if not optically, representative of an actual Al/sub 2/O/sub 3/ laser window.

  20. Ruby and sapphire from Jegdalek, Afghanistan

    Science.gov (United States)

    Bowersox, G.W.; Foord, E.E.; Laurs, B.M.; Shigley, J.E.; Smith, C.P.

    2000-01-01

    This study provides detailed mining and gemological information on the Jegdalek deposit, in east-central Afghanistan, which is hosted by elongate beds of corundum-bearing marble. Some facet-grade ruby has been recovered, but most of the material consists of semitransparent pink sapphire of cabochon or carving quality. The most common internal features are dense concentrations of healed and nonhealed fracture planes and lamellar twin planes. Color zoning is common, and calcite, apatite, zircon, mica, iron sulfide minerals, graphite, rutile, aluminum hydroxide, and other minerals are also present in some samples. Although the reserves appear to be large, future potential will depend on the establishment of a stable government and the introduction of modern mining and exploration techniques. ?? 2000 Gemological Institute of America.

  1. Synthesis of titanium sapphire by ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Morpeth, L.D.; McCallum, J.C.; Nugent, K.W. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1998-06-01

    Since laser action was first demonstrated in titanium sapphire (Ti:Al{sub 2}O{sub 3}) in 1982, it has become the most widely used tunable solid state laser source. The development of a titanium sapphire laser in a waveguide geometry would yield an elegant, compact, versatile and highly tunable light source useful for applications in many areas including optical telecommunications. We are investigating whether ion implantation techniques can be utilised to produce suitable crystal quality and waveguide geometry for fabrication of a Ti:Al{sub 2}O{sub 3} waveguide laser. The implantation of Ti and O ions into c-axis oriented {alpha}-Al{sub 2}O{sub 3} followed by subsequent thermal annealing under various conditions has been investigated as a means of forming the waveguide and optimising the fraction of Ti ions that have the correct oxidation state required for laser operation. A Raman Microprobe is being used to investigate the photo-luminescence associated with Ti{sup 3+} ion. Initial photoluminescence measurements of ion implanted samples are encouraging and reveal a broad luminescence profile over a range of {approx} .6 to .9 {mu}m, similar to that expected from Ti{sup 3+}. Rutherford Backscattering and Ion Channelling analysis have been used to study the crystal structure of the samples following implantation and annealing. This enables optimisation of the implantation parameters and annealing conditions to minimise defect levels which would otherwise limit the ability of light to propagate in the Ti:Al{sub 2O}3 waveguide. (authors). 8 refs., 3 figs.

  2. Polishing Sapphire Substrates by 355 nm Ultraviolet Laser

    Directory of Open Access Journals (Sweden)

    X. Wei

    2012-01-01

    Full Text Available This paper tries to investigate a novel polishing technology with high efficiency and nice surface quality for sapphire crystal that has high hardness, wear resistance, and chemical stability. A Q-switched 355 nm ultraviolet laser with nanosecond pulses was set up and used to polish sapphire substrate in different conditions in this paper. Surface roughness Ra of polished sapphire was measured with surface profiler, and the surface topography was observed with scanning electronic microscope. The effects of processing parameters as laser energy, pulse repetition rate, scanning speed, incident angle, scanning patterns, and initial surface conditions on surface roughness were analyzed.

  3. Retrospective dosimetry: Dose evaluation using unheated and heated quartz from a radioactive waste storage building

    DEFF Research Database (Denmark)

    Jain, M.; Bøtter-Jensen, L.; Murray, A.S.

    2002-01-01

    and particularly in nuclear installations. These materials contain natural dosemeters Such as quartz. which usually is less sensitive than its heated counterpart. The potential of quartz extracted from mortar in a wall of a low-level radioactive-waste storage facility containing distributed sources of Co-60 and Cs...

  4. Shock metamorphism of deformed quartz

    Science.gov (United States)

    Gratz, Andrew J.; Christie, John; Tyburczy, James; Ahrens, Thomas; Pongratz, Peter

    1988-01-01

    The effect produced by shock loading (to peak pressures of 12 and 24) on deformed synthetic quartz containing a dislocation and abundant bubbles and small inclusions was investigated, and the relationships between preexisting dislocation density shock lamellae in the target material were examined. The resultant material was found to be inhomogeneously deformed and extremely fractured. Results of TEM examinations indicate that no change in dislocation density was caused by shock loading except in regions containing shock lamellae, where the dislocation density was lowered. The shock-induced defects tend to nucleate on and be controlled by preexisting stress concentrators; shock lamellae, glassy veins, and most curviplanar defects form in tension, presumably during release. An extremely mobile silica fluid is formed and injected into fractures during release, which forcibly removes crystalline fragments from vein walls. It is concluded that shock deformation in quartz is dominated by fracture and melting.

  5. Buffer layers for high-Tc thin films on sapphire

    Science.gov (United States)

    Wu, X. D.; Foltyn, S. R.; Muenchausen, R. E.; Cooke, D. W.; Pique, A.; Kalokitis, D.; Pendrick, V.; Belohoubek, E.

    1992-01-01

    Buffer layers of various oxides including CeO2 and yttrium-stabilized zirconia (YSZ) have been deposited on R-plane sapphire. The orientation and crystallinity of the layers were optimized to promote epitaxial growth of YBa2Cu3O(7-delta) (YBCO) thin films. An ion beam channeling minimum yield of about 3 percent was obtained in the CeO2 layer on sapphire, indicating excellent crystallinity of the buffer layer. Among the buffer materials used, CeO2 was found to be the best one for YBCO thin films on R-plane sapphire. High Tc and Jc were obtained in YBCO thin films on sapphire with buffer layers. Surface resistances of the YBCO films were about 4 mOmega at 77 K and 25 GHz.

  6. Study on the Anisotropy of Meniscus in the Growing Sapphire

    Institute of Scientific and Technical Information of China (English)

    YAO Tai; ZUO Hong-bo; HAN Jie-cai; MENG Song-he; ZHANG Ming-fu; LI Chang-qing; Grigoryan Benik

    2006-01-01

    This study is aimed at predicting the relationship between the meniscus and the quality of the sapphire crystals produced by the micro-pulling and shoulder at cooled center (SAPMIC) technique. As with different orientations, the shapes of the meniscus vary, so an investigation into the anisotropy of the meniscus shapes is very important for the final quality of the sapphire crystal. An effective model to describe meniscus shapes and their formation process has been presented. The model has been applied to a sapphire crystal of 200 mm diameter in order to check its reliability. The results show that the model proves to be useful for forecasting the final shapes of the sapphire crystal made by the SAPMIC technique.

  7. Buffer layers for high-Tc thin films on sapphire

    Science.gov (United States)

    Wu, X. D.; Foltyn, S. R.; Muenchausen, R. E.; Cooke, D. W.; Pique, A.; Kalokitis, D.; Pendrick, V.; Belohoubek, E.

    1992-01-01

    Buffer layers of various oxides including CeO2 and yttrium-stabilized zirconia (YSZ) have been deposited on R-plane sapphire. The orientation and crystallinity of the layers were optimized to promote epitaxial growth of YBa2Cu3O(7-delta) (YBCO) thin films. An ion beam channeling minimum yield of about 3 percent was obtained in the CeO2 layer on sapphire, indicating excellent crystallinity of the buffer layer. Among the buffer materials used, CeO2 was found to be the best one for YBCO thin films on R-plane sapphire. High Tc and Jc were obtained in YBCO thin films on sapphire with buffer layers. Surface resistances of the YBCO films were about 4 mOmega at 77 K and 25 GHz.

  8. Second generation 50 K dual-mode sapphire oscillator.

    Science.gov (United States)

    Anstie, James D; Hartnett, John G; Tobar, Michael E; Ivanov, Eugene N; Stanwix, Paul L

    2006-02-01

    Low-temperature, high-precision sapphire resonators exhibit a turning point in mode frequency-temperature dependence at around 10 K. This, along with sapphire's extremely low dielectric losses at microwave frequencies, results in oscillator fractional frequency stabilities on the order of 10(-15). At higher temperatures the lack of a turning point makes single-mode oscillators very sensitive to temperature fluctuations. By exciting two quasi-orthogonal whispering gallery (WG) modes in a single sapphire resonator, a turning point in the frequency-temperature dependence can be found in the beat frequency between the two modes. A temperature control technique based on mode frequency temperature dependence has been used to maintain the sapphire at this turning point and the fractional frequency instability of the beat frequency has been measured to be at a level of 4.3 X 10(-14) over 1 s, dropping to 3.5 X 10(-14) over 4 s integration time.

  9. Nanostructured sapphire optical fiber for sensing in harsh environments

    Science.gov (United States)

    Chen, Hui; Liu, Kai; Ma, Yiwei; Tian, Fei; Du, Henry

    2017-05-01

    We describe an innovative and scalable strategy of transforming a commercial unclad sapphire optical fiber to an allalumina nanostructured sapphire optical fiber (NSOF) that overcomes decades-long challenges faced in the field of sapphire fiber optics. The strategy entails fiber coating with metal Al followed by subsequent anodization to form anodized alumina oxide (AAO) cladding of highly organized pore channel structure. We show that Ag nanoparticles entrapped in AAO show excellent structural and morphological stability and less susceptibility to oxidation for potential high-temperature surface-enhanced Raman Scattering (SERS). We reveal, with aid of numerical simulations, that the AAO cladding greatly increases the evanescent-field overlap both in power and extent and that lower porosity of AAO results in higher evanescent-field overlap. This work has opened the door to new sapphire fiber-based sensor design and sensor architecture.

  10. Synkinematic quartz cementation in partially open fractures in sandstones

    Science.gov (United States)

    Ukar, Estibalitz; Laubach, Stephen E.; Fall, Andras; Eichhubl, Peter

    2014-05-01

    Faults and networks of naturally open fractures can provide open conduits for fluid flow, and may play a significant role in hydrocarbon recovery, hydrogeology, and CO2 sequestration. However, sandstone fracture systems are commonly infilled, at least to some degree, by quartz cement, which can stiffen and occlude fractures. Such cement deposits can systematically reduce the overall permeability enhancement due to open fractures (by reducing open fracture length) and result in permeability anisotropies. Thus, it is important to identify the factors that control the precipitation of quartz in fractures in order to identify potential fluid conduits under the present-day stress field. In many sandstones, quartz nucleates syntaxially on quartz grain or cement substrate of the fracture wall, and extends between fracture walls only locally, forming pillars or bridges. Scanning electron microscope cathodoluminescence (SEM-CL) images reveal that the core of these bridges are made up of bands of broken and resealed cement containing wall-parallel fluid inclusion planes. The fluid inclusion-rich core is usually surrounded by a layer of inclusion-poor clear quartz that comprises the lateral cement. Such crack-seal textures indicate that this phase was precipitating while the fractures were actively opening (synkinematic growth). Rapid quartz accumulation is generally believed to require temperatures of 80°C or more. Fluid inclusion thermometry and Raman spectroscopy of two-phase aqueous fluid-inclusions trapped in crack-seal bands may be used to track the P-T-X evolution of pore fluids during fracture opening and crack-seal cementation of quartz. Quartz cement bridges across opening mode fractures in the Cretaceous Travis Peak Formation of the tectonically quiescent East Texas Basin indicate individual fractures opened over a 48 m.y. time span at rates of 16-23 µm/m.y. Similarly, the Upper Cretaceous Mesaverde Group in the Piceance Basin, Colorado contains fractures that

  11. Neutron Transmission through Sapphire Crystals: Experiments and Simulations

    OpenAIRE

    Rantsiou, Emmanouela; Filges, Uwe; Panzner, Tobias; Klinkby, Esben Bryndt

    2013-01-01

    Sapphire crystals are excellent filters of fast neutrons, while at the same time exhibit moderate to very little absorption at smaller energies. We have performed an extensive series of measurements in order to quantify the above effect. Alongside our experiments, we have performed a series of simulations, in order to reproduce the transmission of cold neutrons through sapphire crystals. Thosesimulations were part of the effort of validating and improving the newly developed interface between...

  12. Investigation of sapphire detector designed for single particle detection

    Energy Technology Data Exchange (ETDEWEB)

    Karacheban, Olena; Hempel, Maria [DESY, Zeuthen (Germany); Brandenburg University of Technology, Cottbus (Germany); Afanaciev, Konstantin [NCPHEP, Minsk (Belarus); Henschel, Hans; Lange, Wolfgang; Leonard, Jessica [DESY, Zeuthen (Germany); Levy, Itamar [Tel Aviv University, Tel Aviv (Israel); Lohmann, Wolfgang [Brandenburg University of Technology, Cottbus (Germany); CERN, Geneva (Switzerland); Novgorodova, Olga [Technical University, Dresden (Germany); Schuwalow, Sergej [DESY, Hamburg (Germany)

    2015-07-01

    For beam halo and beam loss monitoring systems at accelerators extremely radiation hard sensors are needed. Single crystal sapphire is a promising material. Industrially grown sapphire wafers are available in large sizes, are low in cost and can be operated at room temperature. Currently sapphire sensors are used for a beam-loss monitor at FLASH,detecting bunches of particles crossing the sensors simultaneously. Here we present a multichannel detector designed for single minimum ionising particle detection using a stack of sapphire plates. The performance of the detector was studied in a 5 GeV electron beam at DESY-II. The detector was operated together with the EUDET beam telescope, which allowed the reconstruction of the position of the hits at the detector. For each sapphire plate the charge collection efficiency was measured as a function of the bias voltage and the signal size as a function of the hit position with respect to the metal electrodes. The data confirms that mainly electrons contribute to the signal. Based on these results the next generation sapphire detector will be designed.

  13. Ti : sapphire laser synchronised with femtosecond Yb pump laser via nonlinear pulse coupling in Ti : sapphire active medium

    Science.gov (United States)

    Didenko, N. V.; Konyashchenko, A. V.; Konyashchenko, D. A.; Kostryukov, P. V.; Kuritsyn, I. I.; Lutsenko, A. P.; Mavritskiy, A. O.

    2017-02-01

    A laser system utilising the method of synchronous pumping of a Ti : sapphire laser by a high-power femtosecond Yb3+-doped laser is described. The pulse repetition rate of the Ti : sapphire laser is successfully locked to the repetition rate of the Yb laser for more than 6 hours without the use of any additional electronics. The measured timing jitter is shown to be less than 1 fs. A simple qualitative model addressing the synchronisation mechanism utilising the cross-phase modulation of oscillation and pump pulses within a Ti : sapphire active medium is proposed. Output parameters of the Ti : sapphire laser as functions of its cavity length are discussed in terms of this model.

  14. GaN on sapphire mesa technology

    Energy Technology Data Exchange (ETDEWEB)

    Herfurth, Patrick; Men, Yakiv; Kohn, Erhard [Institute of Electron Devices and Circuits, Ulm University, Albert-Einstein Allee 45, 89081 Ulm (Germany); Roesch, Rudolph [Institute of Optoelectronics, Albert-Einstein Allee 45, 89081 Ulm (Germany); Carlin, Jean-Francois; Grandjean, Nicolas [Laboratory of Advanced Semiconductors for Photonics and Electronics, Ecole Polytechnique Federal de Lausanne, 1015 Lausanne (Switzerland)

    2012-03-15

    This contribution reports on a GaN on sapphire mesa technology for lattice matched InAlN/GaN HEMTs similar to a silicon on insulator technology. Ultrathin buffer layers between 500 nm and 100 nm have been deep mesa etched down to the substrate to avoid cross talk between devices through the buffer and provide full transparency outside the active device area (of special interest to biochemical sensor applications).The heterostructure characteristics were: N{sub S}> 1.6 x 10{sup 13} cm{sup -2}, R{sub sh}< 600 {omega}/{open_square}. 0.25 {mu}m gate length HEMT device characteristics are moderate, but essentially similar down to 200 nm buffer thickness. Devices on 100 nm buffer layer are still difficult to reproduce. I{sub on}/I{sub off} was up to 10{sup 9} and sub-threshold slopes down to 90 mV/dec (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Radioluminescence of synthetic quartz related to alkali ions

    Energy Technology Data Exchange (ETDEWEB)

    Martini, M., E-mail: m.martini@unimib.it [Dipartimento di Scienza dei Materiali, Universita degli Studi di Milano Bicocca, Via Cozzi 53, I-20125 Milano (Italy); INFN-Sezione di Milano Bicocca, Via Cozzi 53, I-20125 Milano (Italy); Fasoli, M. [Dipartimento di Scienza dei Materiali, Universita degli Studi di Milano Bicocca, Via Cozzi 53, I-20125 Milano (Italy); Galli, A. [Dipartimento di Scienza dei Materiali, Universita degli Studi di Milano Bicocca, Via Cozzi 53, I-20125 Milano (Italy); Istituto di Fotonica e Nanostrutture, IFN-CNR (Italy); Villa, I. [Dipartimento di Scienza dei Materiali, Universita degli Studi di Milano Bicocca, Via Cozzi 53, I-20125 Milano (Italy); Guibert, P. [IRAMAT-CRP2A (Institut de recherche sur les Archeomateriaux), UMR no. 5060, CNRS-Universite Bordeaux III, F-33607 Pessac (France)

    2012-04-15

    The radioluminescence (RL) of synthetic quartzes (GEMMA Quartz and Crystal Company) has been measured at room temperature. Some samples were treated by electrodiffusion ('sweeping') in order to change the concentrations of alkali ions, mainly Li{sup +} and Na{sup +}, which in quartz are known to be linked to Al ions, substitutional for Si ions. The RL emission spectra show evidence of a role of alkali ions in affecting some specific emissions. All the spectra could be analysed as composed of four bands in the blue and UV region. Specifically, the well known blue emission at around 470 nm was seen to be composed by two bands at 430 nm (2.86 eV) and at 485 nm (2.53 eV). Effects of irradiation, during the RL measurements, were clearly seen only in the 'Li swept in' sample, namely an increase in the 485 nm band intensity and a decrease in the 430 nm band one. The previously reported UV emission was detected at 355 nm (3.44 eV) in all the samples, being the most intense band in the 'swept out' sample. A further UV emission was detected at 315 nm (3.94 eV), more intense in untreated samples. Possible assignments of the detected emission bands are discussed in relation to the defects of quartz, specifically focusing on the Al centres that are most affected by sweeping procedures. - Highlights: Black-Right-Pointing-Pointer Contribution to the understanding of relationships between defects in quartz and luminescence emissions. Black-Right-Pointing-Pointer Role of charge compensators at substitutional Al sites in the optical properties of quartz. Black-Right-Pointing-Pointer Evidence of the double nature of the 'blue emission' (around 470 nm).

  16. A peek into the history of sapphire crystal growth

    Science.gov (United States)

    Harris, Daniel C.

    2003-09-01

    After the chemical compositions of sapphire and ruby were unraveled in the middle of the 19th century, chemists set out to grow artificial crystals of these valuable gemstones. In 1885 a dealer in Geneva began to sell ruby that is now believed to have been created by flame fusion. Gemnologists rapidly concluded that the stones were artificial, but the Geneva ruby stimulated A. V. L. Verneuil in Paris to develop a flame fusion process to produce higher quality ruby and sapphire. By 1900 there was brisk demand for ruby manufactured by Verneuil's method, even though Verneuil did not publicly announce his work until 1902 and did not publish details until 1904. The Verneuil process was used with little alteration for the next 50 years. From 1932-1953, S. K. Popov in the Soviet Union established a capability for manufacturing high quality sapphire by the Verneuil process. In the U.S., under government contract, Linde Air Products Co. implemented the Verneuil process for ruby and sapphire when European sources were cut off during World War II. These materials were essential to the war effort for jewel bearings in precision instruments. In the 1960s and 1970s, the Czochralski process was implemented by Linde and its successor, Union Carbide, to make higher crystal quality material for ruby lasers. Stimulated by a government contract for structural fibers in 1966, H. LaBelle invented edge-defined film-fed growth (EFG). The Saphikon company, which is currently owned by Saint-Gobain, evolved from this effort. Independently and simultaneously, Stepanov developed edge-defined film-fed growth in the Soviet Union. In 1967 F. Schmid and D. Viechnicki at the Army Materials Research Lab grew sapphire by the heat exchanger method (HEM). Schmid went on to establish Crystal Systems, Inc. around this technology. Rotem Industries, founded in Israel in 1969, perfected the growth of sapphire hemispheres and near-net-shape domes by gradient solidification. In the U.S., growth of near

  17. Evolution of the sapphire industry: Rubicon Technology and Gavish

    Science.gov (United States)

    Harris, Daniel C.

    2009-05-01

    A. Verneuil developed flame fusion to grow sapphire and ruby on a commercial scale around 1890. Flame fusion was further perfected by Popov in the Soviet Union in the 1930s and by Linde Air Products Co. in the U.S. during World War II. Union Carbide Corp., the successor to Linde, developed Czochralski crystal growth for sapphire laser materials in the 1960s. Stepanov in the Soviet Union published his sapphire growth method in 1959. Edge-Defined Film-Fed Growth (EFG), which is similar to the Stepanov method, was developed by H. Labelle in the U. S. in the 1960s and 1970s. The Heat Exchanger Method (HEM), invented by F. Schmid and D. Viechnicki in 1967 was commercialized in the 1970s. Gradient solidification was invented in Israel in the 1970s by J. Makovsky. The Horizontal Directional Solidification Method (HDSM) proposed by Kh. S. Bagdasorov in the Soviet Union in the 1960s was further developed at the Institute for Single Crystals in Ukraine. Kyropoulos growth of sapphire, known as GOI crystal growth in the Soviet Union, was developed by M. Musatov at the State Optical Institute in St. Petersburg in the 1970s and 1980s. At the Institute for Single Crystals in Ukraine, E. Dobrovinskaya characterized Verneuil, Czochralsky, Bagdasarov, and GOI sapphire. In 1995, she emigrated to the United States and joined S&R Rubicon, founded near Chicago by R. Mogilevsky initially to import sapphire and ruby. Mogilevsky began producing sapphire by the Kyropoulos method in 1999. In 2000 the company name was changed to Rubicon Technology. Today, Dobrovinskaya is Chief Scientist and Rubicon produces high quality Kyropoulos sapphire substrates for solid-state lighting. In 1995, H. Branover of Ben Gurion University and a sole investor founded Gavish, which is Hebrew for "crystal." They invited another veteran of the Ukrainian Institute for Single Crystals, V. Pishchik, to become Chief Scientist. Under Pishchik's technical leadership and J. Sragowicz's business leadership, Gavish now

  18. Scaling STI's sapphire cryocooler for applications requiring higher heat loads

    Science.gov (United States)

    Karandikar, Abhijit; Fiedler, Andreas

    2012-06-01

    Superconductor Technologies Inc. (STI) developed the Sapphire cryocooler specifically for the SuperLink® product; a high performance superconducting Radio Frequency (RF) front-end receiver used by wireless carriers such as Verizon Wireless and AT&T to improve network cell coverage and data speeds. STI has built and deployed over 6,000 systems operating 24 hours a day (24/7), 7 days a week in the field since 1999. Sapphire is an integrated free piston Stirling cycle cryocooler with a cooling capacity of 5 Watts at 77 Kelvin (K) with less than 100 Watts (W) input power. It has a field-proven Mean Time Between Failure (MTBF) of well over 1 million hours, requires zero maintenance and has logged over 250 million cumulative runtime hours. The Sapphire cooler is built on a scalable technology platform, enabling the design of machines with cooling capacities greater than 1 kilowatt (kW). This scalable platform also extends the same outstanding attributes as the Sapphire cooler, namely high reliability, zero maintenance, and compact size - all at a competitive cost. This paper will discuss emerging applications requiring higher heat loads and these attributes, describe Sapphire, and show a preliminary concept of a scaled machine with a 100 W cooling capacity.

  19. Dose response on the 110 °C thermoluminescence peak of un-heated, synthetic Merck quartz

    Energy Technology Data Exchange (ETDEWEB)

    Kaya Keleş, Şule, E-mail: sule.kaya@ankara.edu.tr; Meriç, Niyazi; Polymeris, George S.

    2016-07-15

    Studies on 110 °C TL peak have been carried out using natural quartz from different origins and synthetic quartz produced by different suppliers. The interest in quartz is due to its usage in dating and retrospective dosimetry as a main material; both synthetic and natural types of quartz yield the 110 °C TL peak in their glow curve. In most studies to understand the physical mechanism behind the TL system, synthetic quartz samples are used and there are many investigations about dose response, in both low and high radiation dose region. In these studies generally synthetic quartz samples produced by Sawyer Research Products are used and the studies showed that both heated and un-heated synthetic quartz samples have intense supra-linear responses. Supra-linearity was enhanced by applying a pre-irradiation while several models have been developed towards an explanation to these supra-linearity effects. In this study commercially available synthetic Merck quartz was used. Different combinations of optical filters were used to obtain dose response curves upto 266 Gy and the effect of pre-dose to these dose response curves was studied. Un-pre-dosed Merck quartz samples dose supra-linearity index is below 1 independently on the optical filters; so Merck quartz showed linear or sub-linear dose response.

  20. Nonlinear optical characterization of GaN layers grown by MOCVD on sapphire[Metal Organic Chemical Vapor Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Tiginyanu, I.M.; Kravetsky, I.V.; Pavlidis, D.; Eisenbach, A.; Hildebrandt, R.; Marowsky, G.; Hartnagel, H.L.

    2000-07-01

    Optical second and third harmonic generation measurements were carried out on GaN layers grown by metalorganic chemical vapor deposition (MOCVD) on sapphire substrates. The measured d{sub 33} is 33 times the d{sub 11} of quartz. The angular dependence of second-harmonic intensity as well as the measured ratios d{sub 33}/d{sub 15} = {minus}2.02 and d{sub 33}/d{sub 31} = {minus}2.03 confirm the wurzite structure of the studied GaN layers with the optical c-axis oriented perpendicular to the sample surface. Fine oscillations were observed in the measured second and third harmonic angular dependencies. A simple model based on the interference of the fundamental beam in the sample was used to explain these oscillations.

  1. Voltage-Controlled Sapphire Oscillator: Design, Development, and Preliminary Performance

    Science.gov (United States)

    Wang, R. T.; Dick, G. J.; Tjoelker, R. L.

    2007-08-01

    We present the design for a new short-term frequency standard, the voltage-controlled sapphire oscillator, as a practical and lower-cost alternative to a cryogenic sapphire oscillator operating at liquid helium temperatures. Performance goals are a frequency stability of 1 x 10^-14 (1 second equal to or less than tau equal to or less than 100 seconds), more than 2 years of continuous operation, and practical operability. Key elements include the sapphire resonator, low-power and long-life cryocooler, frequency compensation method, and cryo-Pound design. We report the design verification, experimental results, and test results of the cryocooler environmental sensitivity, as well as a preliminary stability measurement.

  2. Clinical Application of the Sapphire Unfolder Lens Injection System

    Institute of Scientific and Technical Information of China (English)

    Weiai Guo; Danying Zheng; Zhenyu Li; Yiyong Qian; Zhenping Zhang

    2002-01-01

    Purpose: To summarize the clinical experience of 300 cases using the Sapphire unfloder intraocular lens (IOL) injection system.Methods: After the standard phacoemulsification, an AR40e IOL was implanted using the Sapphire Unfolder. The involved problems during and after the operation were observed and analyzed.Results:The complications occurred during the operation including the crack at the haptic-optic junction in 2 cases, slight kink in the haptic in 5 cases, IOL clamp into the cartridge in 2 cases, posterior capsular rupture in 2 cases and endothelium damage in the central small area in 4 cases. All the patients recovered successfully with IOLs in good position.Conclusion: IOL implantation with the Sapphire Unfolder led to no serious complications and got the satisfactory results.

  3. The Suitability Of Local Quartz Sand In The Production Of Bath Crucibles.

    Directory of Open Access Journals (Sweden)

    C. O. Okpanachi

    2015-08-01

    Full Text Available The suitability of local quartz sand in the production of bath crucibles is a study that was carried out in order to impart overall strength on bath crucibles hence reduce breakages during fettling. Therefore this research constitutes a study to enhance the efficiency of production of bath crucibles by addition of quartz sand in slip preparation. The steps taken in the beneficiation of quartz sand for the production of bath crucibles are comminution which entails crushing and milling classification washing liquid dispersion sizing and reduction of iron content by magnetic separation. The slip contains materials like plastic clay feldspar kaolin talc sodium silicate water quartz sand etc. These were all milled in the ball mill for slip production casting and fettling glazing and sintering to get final bath crucibles as the end products. Quartz sand is used in a variety of products essentially as raw material for the foundry casting and glass industries and also in chemicals water filtration and ceramics the heat resistance nature of quartz sand makes it an excellent refractory substance for these industrial processes. Slip can be prepared for production of bath crucibles without the inclusion of quartz sand however the addition of quartz sand is needed to improve the mechanical performance of the slip in the production of bath crucibles.

  4. Oxygen isotope equilibration systematics between quartz and water

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, A. (Hebrew Univ., Jerusalem, Israel); Beckinsale, R.D.

    1979-01-01

    The /sup 18/O//sup 16/O fractionation accompanying the hydrothermal crystallization of quartz from silicic acid at 265/sup 0/ to 465/sup 0/C has been studied in order to assess the influences of (a) rate of quartz formation, (b) the nature of the reaction mechanism, and (c) temperature. At 360/sup 0/ and 465/sup 0/C, there are no indications of rate effects influencing isotope partitioning, but at 265/sup 0/C (where fractionation factors show an unusally large scatter) the evidence is inconclusive in this respect. All reaction appears to occur through solution-precipitation processes, with the intermediate phases, cristobalite and silica K, giving identical fractionation factors (within experimental errors) to quartz samples formed at the same temperature. The temperature-dependence of fractionation in the range 265/sup 0/ to 465/sup 0/C is given by the equation 10/sup 3/ ln ..cap alpha..(SiO/sub 2/--H/sub 2/O) = 3.05 x 10/sup 6/T/sup -2/ - 2.09. The data are in good agreement with other experimental calibrations of the quartz-water fractionation.

  5. Development of Quartz Fiber Calorimetry

    CERN Multimedia

    2002-01-01

    % RD40 \\\\ \\\\ Very Forward Calorimeters (VFCs) in LHC detectors should cover the pseudorapidity range from $\\eta$~=~2.5 to at least $\\eta$~=~5 in order to compute missing transverse energy and for jet tagging. Operation at such high rapidity requires the use of a calorimetry technique that is very radiation resistant, fast and insensitive to radioactivity (especially to neutrons). This can be accomplished through the Quartz-Calorimeter~(Q-Cal) concept of embedding silica core fibers, that resist to the Gigarad radiation level, into an absorber. In this calorimeter the shower particles produce light through the Cherenkov effect generating a signal less than 10~ns in duration. Unique to this new technology the visible energy of hadronic showers has a transverse dimension nearly an order of magnitude smaller than that in conventional calorimeters, enabling precise spatial resolution, sharper isolation cuts and better jet recognition against the minimum bias events background. Last but not least, most radioactive ...

  6. Blocks and residual stresses in shaped sapphire single crystals

    Science.gov (United States)

    Krymov, V. M.; Nosov, Yu. G.; Bakholdin, S. I.; Maslov, V. N.; Shul‧pina, I. L.; Nikolaev, V. I.

    2017-01-01

    The formation of blocks and residual stresses in shaped sapphire crystals grown from the melt by the Stepanov method (EFG) has been studied. The probability of block formation is higher for the growth along the c axis compared to that grown in the a-axis direction. The distribution of residual stress in sapphire crystals of tubular, rectangular and round cross section was measured by the conoscopy method. It was found that the magnitude of the residual stress increases from the center to the periphery of the crystal and reaches up to about 20 MPa. Residual stress tensor components for solid round rod and tubular single crystals were determined by numerical integration.

  7. Inversion domains in AlN grown on (0001) sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Jasinski, J.; Liliental-Weber, Z.; Paduano, Q.S.; Weyburne, D.W.

    2003-08-25

    Al-polarity inversion domains formed during AlN layer growth on (0001) sapphire were identified using transmission electron microscopy (TEM). They resemble columnar inversion domains reported for GaN films grown on (0001) sapphire. However, for AlN, these columns have a V-like shape with boundaries that deviate by 2 {+-} 0.5{sup o} from the c-axis. TEM identification of these defects agrees with the post-growth surface morphology as well as with the microstructure revealed by etching in hot aqueous KOH.

  8. Sea level characterization of a 1100 g sapphire bolometer

    CERN Document Server

    Pécourt, S; Bobin, C; Coron, N; Jesus, M D; Hadjout, J P; Leblanc, J W; Marcillac, P D

    1999-01-01

    A first characterization of a 1100 g sapphire bolometer, performed at sea level and at a working temperature of 40 mK, is presented. Despite perturbations coming from the high-radioactive background and cosmic rays, calibration spectra could be achieved with an internal alpha source and a sup 5 sup 7 Co gamma-ray source: the experimental threshold is 25 keV, while the FWHM resolution is 17.4 keV for the 122 keV peak. Possible heat release effects are discussed, and a new limit of 9x10 sup - sup 1 sup 4 W/g is obtained for sapphire.

  9. Quartz red TL SAR equivalent dose overestimation for Chinese loess

    DEFF Research Database (Denmark)

    Lai, Z.P.; Murray, A.S.; Bailey, R.M.

    2006-01-01

    For the red TL of quartz extracted from Chinese loess, the single-aliquot regenerative-dose (SAR) procedure overestimates the known laboratory doses in dose recovery test. The overestimation is the result of the first heating during the measurement of natural TL signal causing a sensitivity...... of red TL, which is found to be more than 100 Gy. (c) 2005 Elsevier Ltd. All rights reserved....

  10. The Quartz Analog Watch: A Wonder Machine.

    Science.gov (United States)

    Crane, H. Richard, Ed.

    1993-01-01

    Summarizes how a quartz watch works. Discusses the quartz crystal, its form, and how its frequency is set to a standard; the integrated circuit chip that drives the crystal in vibration, scales its frequency down, and forms pulses that turn the motor; and the motor that drives the gear train that turns the hands. (ZWH)

  11. Can enantiomorphic crystals like quartz play a role in the origin of homochirality on earth?

    Science.gov (United States)

    Klabunovskii, E I

    2001-01-01

    This communication reviews the possible actions of enantiomorphic crystals on the surface of Earth as sources of homochirality of organic compounds. The discovery of asymmetric adsorption and asymmetric catalysis involving optically active quartz crystals has led some authors to conclude that this source of asymmetry played an important role as a source of homochirality in nature, a concept that later proved erroneous. Moreover, data regarding the preponderance in nature of l-quartz crystals have been used to confirm calculations of the parity violation energy difference (PVED) for l-quartz and, hence, to explain the prevalence of L-amino acids and D-sugars in living matter. As discussed here, quartz and other enantiomorphs such as sodium chlorate can produce chiral intermediates active in autocatalytical processes. Our most recent compilation of the literature, however, reveals that the distribution of d- and l-quartz crystals at the surface of the Earth when all possible locations are included is quite random. Although quartz can serve as an effective asymmetric inductor in autocatalytic processes, it cannot be the source of homochirality of living matter because of the random occurrence of the two types of enantiomorphs. The calculations of PVED values for quartz therefore lack a sound physical basis.

  12. Optimising the separation of quartz and feldspar optically stimulated luminescence using pulsed excitation

    DEFF Research Database (Denmark)

    Ankjærgaard, Christina; Jain, Mayank; Thomsen, Kristina Jørkov;

    2010-01-01

    In luminescence dating, the two most commonly used natural minerals, quartz and feldspar, are exposed to different dose rates in the natural environment, and so record different doses. The luminescence signals also have different stabilities. For accurate dosimetry, the signals from these two...... minerals must be separated, either by physical separation of the mineral grains, or by instrumental separation of the luminescence signals. The luminescence signals from quartz and feldspar have different luminescence lifetimes under pulsed optical stimulation. This difference in lifetime can be used...... to discriminate between the two signals from a mixed quartz-feldspar sample. The purpose of this study is to identify optimum measurement conditions for the best separation of quartz OSL from that of feldspar in a mixed sample using pulsed stimulation and time-resolved OSL. We integrate the signal from 5 μs after...

  13. Change in equilibrium position of misfit dislocations at the GaN/sapphire interface by Si-ion implantation into sapphire. II. Electron energy loss spectroscopic study

    Directory of Open Access Journals (Sweden)

    Sung Bo Lee

    2015-07-01

    Full Text Available In Part I, we have shown that the addition of Si into sapphire by ion implantationmakes the sapphire substrate elastically softer than for the undoped sapphire. The more compliant layer of the Si-implanted sapphire substrate can absorb the misfit stress at the GaN/sapphire interface, which produces a lower threading-dislocation density in the GaN overlayer. Here in Part II, based on experimental results by electron energy loss spectroscopy and a first-principle molecular orbital calculation in the literature, we suggest that the softening effect of Si results from a reduction of ionic bonding strength in sapphire (α-Al2O3 with the substitution of Si for Al.

  14. Structure of shaped sapphire grown from multicapillary dies

    Science.gov (United States)

    Dobrovinskaya, E. R.; Litvinov, L. A.; Pischik, V. V.

    1990-07-01

    Peculiarities in grain structure development have been studied in sapphire crystals grown with multicapillary channels in the die to feed melt to the crystallization zone. A new mechanism of grain boundary formation based on gas-bubble collapse at the crystal-melt interface is proposed.

  15. Single-transverse-mode Ti:sapphire rib waveguide laser

    NARCIS (Netherlands)

    Grivas, C.; Shepherd, D.P.; May-Smith, T.C.; Eason, R.W.; Pollnau, M.

    2005-01-01

    Laser operation of Ti:sapphire rib waveguides fabricated using photolithography and ion beam etching in pulsed laser deposited layers is reported. Polarized laser emission was observed at 792.5 nm with an absorbed pump power threshold of 265 mW, which is more than a factor of 2 lower in comparison t

  16. Neurosurgery contact handheld probe based on sapphire shaped crystal

    Science.gov (United States)

    Shikunova, I. A.; Stryukov, D. O.; Rossolenko, S. N.; Kiselev, A. M.; Kurlov, V. N.

    2017-01-01

    A handheld contact probe based on sapphire shaped crystal is developed for intraoperative spectrally-resolved optical diagnostics, laser coagulation and aspiration of malignant brain tissue. The technology was integrated into the neurosurgical workflow for intraoperative real-time identification and removing of invasive brain cancer.

  17. Temperature-modulated annealing of c-plane sapphire for long-range-ordered atomic steps

    Science.gov (United States)

    Yatsui, Takashi; Kuribara, Kazunori; Sekitani, Tsuyoshi; Someya, Takao; Yoshimoto, Mamoru

    2016-03-01

    High-quality single-crystalline sapphire is used to prepare various semiconductors because of its thermal stability. Here, we applied the tempering technique, which is well known in the production of chocolate, to prepare a sapphire substrate. Surprisingly, we successfully realised millimetre-range ordering of the atomic step of the sapphire substrate. We also obtained a sapphire atomic step with nanometre-scale uniformity in the terrace width and atomic-step height. Such sapphire substrates will find applications in the preparation of various semiconductors and devices.

  18. Integrated Optical Pumping of Cr & Ti-Doped Sapphire Substrates With III-V Nitride Materials

    Science.gov (United States)

    2005-08-24

    the Cr in sapphire could also permit the construction of white light LEDs . Ultimately, an integrated III-V Nitride optical pump for Ti:Sapphire could...substrates by MOCVD. 2. Characterization of doped sapphire/ InGaN structures byPL to simulate electrical injection by laser or LED device structures Part 2 1...Cr:sapphire substrate. Solid line is the spectrum of blue and red light emitted by InGaN LED epitaxially grown on Cr:sapphire substrate. The light was collected

  19. Orientation of Planar Deformation Features (PDFs) in quartz

    Science.gov (United States)

    Langenhorst, F.; Deutsch, A.

    1993-01-01

    Differently oriented single crystal quartz was shocked experimentally at pressures of 20 to 32 GPa and pre-shock temperatures up to 630 C. Based on this systematic investigation, we can demonstrate that the orientation of planar deformation features in quartz is not only dependent on shock pressure but also on pre-shock temperature and shock direction. Moreover, the orientation of Planar Deformation Features (PDF's) is strongly influenced by the set-up in recovery experiments. PDF's in quartz are defined as optically recognizable, planar microstructures diagnostically produced by shock compression. PDF's differ from all kinds of microstructures found in volcanic environment and therefore, their presence is a primary criterion for recognizing impact craters and ejecta layers such as the K/T boundary. Because experiments have shown a pressure dependence of the orientation of PDF's, this property is used extensively for shock wave barometry in natural impact sites. However, the unreflected application of experimental results neglects that parameters such as pre-shock temperature, shock direction, or the experimental arrangement may influence the spatial distribution of PDF's. In order to test this assumption, shock experiments on single crystal quartz at pre-shock temperatures of 20, 275, 540, and 630 C, and with shock directions (1010) and (0001) were performed. Most of the recovery experiments were carried out by using a reverberation technique, whereas in only one experiment a single shock was produced (impedance method). In the former case 0.5 mm thin discs of single crystal quartz were used, in the latter a 15 mm thick cylinder. The orientation of PDF's was measured by means of a conventional universal stage and the results are given. Effects of the experimentation technique can be derived showing the orientation of PDF's in quartz shocked at 27.5 GPa. In comparison to the well defined peaks at (1012) found in samples from reverberation experiments, the impedance

  20. Additive surface complexation modeling of uranium(VI) adsorption onto quartz-sand dominated sediments.

    Science.gov (United States)

    Dong, Wenming; Wan, Jiamin

    2014-06-17

    Many aquifers contaminated by U(VI)-containing acidic plumes are composed predominantly of quartz-sand sediments. The F-Area of the Savannah River Site (SRS) in South Carolina (USA) is an example. To predict U(VI) mobility and natural attenuation, we conducted U(VI) adsorption experiments using the F-Area plume sediments and reference quartz, goethite, and kaolinite. The sediments are composed of ∼96% quartz-sand and 3-4% fine fractions of kaolinite and goethite. We developed a new humic acid adsorption method for determining the relative surface area abundances of goethite and kaolinite in the fine fractions. This method is expected to be applicable to many other binary mineral pairs, and allows successful application of the component additivity (CA) approach based surface complexation modeling (SCM) at the SRS F-Area and other similar aquifers. Our experimental results indicate that quartz has stronger U(VI) adsorption ability per unit surface area than goethite and kaolinite at pH ≤ 4.0. Our modeling results indicate that the binary (goethite/kaolinite) CA-SCM under-predicts U(VI) adsorption to the quartz-sand dominated sediments at pH ≤ 4.0. The new ternary (quartz/goethite/kaolinite) CA-SCM provides excellent predictions. The contributions of quartz-sand, kaolinite, and goethite to U(VI) adsorption and the potential influences of dissolved Al, Si, and Fe are also discussed.

  1. Single-Crystal Sapphire Optical Fiber Sensor Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Pickrell, Gary [Virginia Polytechnic Inst. & State Univ., Blacksburg, VA (United States); Scott, Brian [Virginia Polytechnic Inst. & State Univ., Blacksburg, VA (United States); Wang, Anbo [Virginia Polytechnic Inst. & State Univ., Blacksburg, VA (United States); Yu, Zhihao [Virginia Polytechnic Inst. & State Univ., Blacksburg, VA (United States)

    2013-12-31

    This report summarizes technical progress on the program “Single-Crystal Sapphire Optical Fiber Sensor Instrumentation,” funded by the National Energy Technology Laboratory of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. This project was completed in three phases, each with a separate focus. Phase I of the program, from October 1999 to April 2002, was devoted to development of sensing schema for use in high temperature, harsh environments. Different sensing designs were proposed and tested in the laboratory. Phase II of the program, from April 2002 to April 2009, focused on bringing the sensor technologies, which had already been successfully demonstrated in the laboratory, to a level where the sensors could be deployed in harsh industrial environments and eventually become commercially viable through a series of field tests. Also, a new sensing scheme was developed and tested with numerous advantages over all previous ones in Phase II. Phase III of the program, September 2009 to December 2013, focused on development of the new sensing scheme for field testing in conjunction with materials engineering of the improved sensor packaging lifetimes. In Phase I, three different sensing principles were studied: sapphire air-gap extrinsic Fabry-Perot sensors; intensity-based polarimetric sensors; and broadband polarimetric sensors. Black body radiation tests and corrosion tests were also performed in this phase. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. At the beginning of Phase II, in June 2004, the BPDI sensor was tested at the Wabash River coal gasifier

  2. SAW Temperature Sensor on Quartz.

    Science.gov (United States)

    Zhgoon, Sergei; Shvetsov, Alexander; Ancev, Ivan; Bogoslovsky, Sergei; Sapozhnikov, Gennadiy; Trokhimets, Konstantin; Derkach, Mikhail

    2015-06-01

    For biomedical applications, narrow temperature range and high sensor accuracy requirements define the need for high temperature sensitivity. Wireless SAW sensors connected to antennas need a reference element to account for changes in electromagnetic coupling between the transmitter and receiver antennas. A pair of sensors with different temperature sensitivities may serve as a self-referenced sensor assembly. This justifies the need for materials with useful SAW resonator properties and with the largest difference between temperature coefficients of frequency (TCF) for a resonator pair on a single substrate. We have identified several cuts of quartz having useful properties with a TCF difference up to 140 ppm/°C for a pair of resonators on a single substrate. As a rule, placing such resonators on a single substrate requires their rotation by up to 90° relative to each other. The limited range of cuts presents a unique opportunity to place both resonators along the X+90° direction with one resonator using Bleustein-Gulyaev-Shimizu (BGS) waves (with electrodes placed along the x-axis) and the other one (with electrodes inclined by about ±10° to the x-axis) using quasi-Rayleigh waves. These cuts are close to the 70°Y cut where a high TCF difference is reached together with acceptable characteristics of the resonators. Resonators were designed for all useful cuts (including the 70°Y cut) and tested. The use of different periods in reflectors and interdigital transducer (IDT) together with individual choice of gaps between reflectors and IDT meant achieving low spurious content in resonator responses. The quality factors reached values up to 3500 at central frequencies around 915 MHz for both BGS and quasi-Rayleigh types of waves. The measured difference of the TCF is about 138 ppm/°C on 70°Y cut that is close to the calculated value.

  3. Quartz-Enhanced Photoacoustic Spectroscopy: A Review

    Directory of Open Access Journals (Sweden)

    Pietro Patimisco

    2014-03-01

    Full Text Available A detailed review on the development of quartz-enhanced photoacoustic sensors (QEPAS for the sensitive and selective quantification of molecular trace gas species with resolved spectroscopic features is reported. The basis of the QEPAS technique, the technology available to support this field in terms of key components, such as light sources and quartz-tuning forks and the recent developments in detection methods and performance limitations will be discussed. Furthermore, different experimental QEPAS methods such as: on-beam and off-beam QEPAS, quartz-enhanced evanescent wave photoacoustic detection, modulation-cancellation approach and mid-IR single mode fiber-coupled sensor systems will be reviewed and analysed. A QEPAS sensor operating in the THz range, employing a custom-made quartz-tuning fork and a THz quantum cascade laser will be also described. Finally, we evaluated data reported during the past decade and draw relevant and useful conclusions from this analysis.

  4. Quartz-enhanced photoacoustic spectroscopy: a review.

    Science.gov (United States)

    Patimisco, Pietro; Scamarcio, Gaetano; Tittel, Frank K; Spagnolo, Vincenzo

    2014-03-28

    A detailed review on the development of quartz-enhanced photoacoustic sensors (QEPAS) for the sensitive and selective quantification of molecular trace gas species with resolved spectroscopic features is reported. The basis of the QEPAS technique, the technology available to support this field in terms of key components, such as light sources and quartz-tuning forks and the recent developments in detection methods and performance limitations will be discussed. Furthermore, different experimental QEPAS methods such as: on-beam and off-beam QEPAS, quartz-enhanced evanescent wave photoacoustic detection, modulation-cancellation approach and mid-IR single mode fiber-coupled sensor systems will be reviewed and analysed. A QEPAS sensor operating in the THz range, employing a custom-made quartz-tuning fork and a THz quantum cascade laser will be also described. Finally, we evaluated data reported during the past decade and draw relevant and useful conclusions from this analysis.

  5. Electronic dipole resonance in smoky quartz

    NARCIS (Netherlands)

    Kerssen, J.; Volger, J.

    1967-01-01

    Microwave absorption in smoky quartz mono-crystal is ascribed to resonance transitions of trapped electrons between initially configurational degenerated states, which are Stark-splitted by a polarizing electric field.

  6. Quartz Mountain/Oklahoma Summer Arts Institute.

    Science.gov (United States)

    Frates, Mary Y.; Madeja, Stanley S.

    1982-01-01

    Describes the Quartz Mountain Oklahoma Summer Arts Institute program. It is designed to nurture artistic talent and to provide intensive arts experiences in music, dance, theater, and the visual arts for talented students aged 14-18. (AM)

  7. Comparative pathogenicity of four strains of Aleutian disease virus for pastel and sapphire mink.

    Science.gov (United States)

    Hadlow, W J; Race, R E; Kennedy, R C

    1983-09-01

    Information was sought on the comparative pathogenicity of four North American strains (isolates) of Aleutian disease virus for royal pastel (a non-Aleutian genotype) and sapphire (an Aleutian genotype) mink. The four strains (Utah-1, Ontario [Canada], Montana, and Pullman [Washington]), all of mink origin, were inoculated intraperitoneally and intranasally in serial 10-fold dilutions. As indicated by the appearance of specific antibody (counterimmunoelectrophoresis test), all strains readily infected both color phases of mink, and all strains were equally pathogenic for sapphire mink. Not all strains, however, regularly caused Aleutian disease in pastel mink. Infection of pastel mink with the Utah-1 strain invariably led to fatal disease. Infection with the Ontario strain caused fatal disease nearly as often. The Pullman strain, by contrast, almost never caused disease in infected pastel mink. The pathogenicity of the Montana strain for this color phase was between these extremes. These findings emphasize the need to distinguish between infection and disease when mink are exposed to Aleutian disease virus. The distinction has important implications for understanding the natural history of Aleutian disease virus infection in ranch mink.

  8. Intensity of quartz cathodoluminescence and trace-element content in quartz from the porphyry copper deposit at Butte, Montana

    Science.gov (United States)

    Rusk, B.G.; Reed, M.H.; Dilles, J.H.; Kent, A.J.R.

    2006-01-01

    Textures of hydrothermal quartz revealed by cathodoluminescence using a scanning electron microscope (SEM-CL) reflect the physical and chemical environment of quartz formation. Variations in intensity of SEM-CL can be used to distinguish among quartz from superimposed mineralization events in a single vein. In this study, we present a technique to quantify the cathodoluminescent intensity of quartz within individual and among multiple samples to relate luminescence intensity to specific mineralizing events. This technique has been applied to plutonic quartz and three generations of hydrothermal veins at the porphyry copper deposit in Butte, Montana. Analyzed veins include early quartz-molybdenite veins with potassic alteration, pyrite-quartz veins with sericitic alteration, and Main Stage veins with intense sericitic alteration. CL intensity of quartz is diagnostic of each mineralizing event and can be used to fingerprint quartz and its fluid inclusions, isotopes, trace elements, etc., from specific mineralizing episodes. Furthermore, CL intensity increases proportional to temperature of quartz formation, such that plutonic quartz from the Butte quartz monzonite (BQM) that crystallized at temperatures near 750 ??C luminesces with the highest intensity, whereas quartz that precipitated at ???250 ??C in Main Stage veins luminesces with the least intensity. Trace-element analyses via electron microprobe and laser ablation-ICP-MS indicate that plutonic quartz and each generation of hydrothermal quartz from Butte is dominated by characteristic trace amounts of Al, P, Ti, and Fe. Thus, in addition to CL intensity, each generation of quartz can be distinguished based on its unique trace-element content. Aluminum is generally the most abundant element in all generations of quartz, typically between 50 and 200 ppm, but low-temperature, Main Stage quartz containing 400 to 3600 ppm Al is enriched by an order of magnitude relative to all other quartz generations. Phosphorous

  9. Influence of H2O Rich Fluid Inclusions on Quartz Deformation

    Science.gov (United States)

    Thust, Anja; Heilbronner, Renée.; Stünitz, Holger; Tarantola, Alexandre; Behrens, Harald

    2010-05-01

    The effect of H2O on the strength of quartz is well known and has been discussed many times in the literature (e.g. Griggs & Blacic 1965, Kronenberg 1994). In this project we study the H2O interactions between natural dry quartz and H2O rich fluid inclusions during deformation in the solid medium Griggs apparatus. High pressure and temperature experiments were carried out using a quartz single crystal containing a large number of H2O-rich fluid inclusions. Adjacent to the fluid inclusions the crystal is essentially dry (Kronenberg A.K., (1994): Hydrogen specifications and chemical weakening of quartz, Rev. Mineral. Ser. 29 (1994), pp. 123-176.

  10. Evaluation of trapping parameter of quartz by deconvolution of the glow curves

    Energy Technology Data Exchange (ETDEWEB)

    Gartia, R.K. [Department of Physics, Manipur University, Imphal 795001 (India); Singh, L. Lovedy, E-mail: lovedyo1@yahoo.co.in [Department of Physics, Manipur University, Imphal 795001 (India)

    2011-08-15

    The glow curves of natural quartz excited with different doses of {beta}-irradiation have been subjected to Computerized Glow Curve Deconvolution (CGCD) in the kinetic formalism. The location of the constituent peaks, which are as many as eleven in the temperature region of 27-575 deg. C, has been ascertained by resorting to the second order derivative plot of the glow curve. Not only figure of merit (FOM) but {chi}{sup 2}-test has also been taken as a criterion for the acceptance of goodness of fit. CGCD analysis reveals that the frequency factor of quartz is in the range of 1.50 {+-} 0.26 x 10{sup 11} sec{sup -1}. This analysis lead to the conclusion that the trapping levels of quartz can be approximated by the Urbach's relation E = 27kT{sub m} where T{sub m} is the temperature at the maximum intensity. - Highlights: > Glow curves of natural and beta-irradiated quartz in the temperature range from room temperature to 573 deg. C is analysed. > Frequency factor of quartz is in the range of 1.50 {+-} 0.26 x 10{sup 11} sec{sup -1}. > Trapping levels of quartz can be approximated by the Urbach's relation E = 27kT{sub m}.

  11. Characterization of hydrothermal green quartz produced by gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Enokihara, Cyro T.; Rela, Paulo R., E-mail: cteiti@ipen.br, E-mail: prela06@yahoo.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Schultz-Güttler, Rainer A., E-mail: rainersgut@gmail.com [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Geociencias

    2015-07-01

    A specific variety of quartz showing a green color in nature or induced artificially by radiation gamma ({sup 60}Co) is quite rare. Only two occurrences are known today, where this type of quartz can be found: Canada, at the Thunder Bay Amethyst Mine, Ontario and Brazil, at widely scattered geode occurrences along a 600 km stretch from Quarai at Brazils southern most tip to Uberlandia in Minas Gerais. These two occurrences have been formed by strong hydrothermal activities.That way much quartz crystals showed a very fast growth history facilitating the formation of growth defects (twinning, small angle tilting, mosaic growth, striations) and the uptake of water in form of micro inclusions, molecular water, silanol (Si-OH) and OH. In the present work the material analyzed is from hydrothermal regimes found in intrusions of basaltic rocks located in the Rio Grande do Sul state. To characterize these materials, colored green by gamma rays, analyses by ICP, electron microscopy, water loss techniques and UV-VIS or NIR-FTIR spectroscopic measurements have been made. Silanol complexes are formed, which by radiation due to gamma rays form the color center NBOHC (Non-bonding Oxygen Hole Center), showing absorption between 590 to 620 nm, responsible for the green color. The water content with up to 3200 ppm by weight exceeds the amount of charge balancing cations (Fe, Al, Li). There is no correlation between water content and cations as in other color varieties. (author)

  12. Ti:sapphire laser with long-pulse lamp pumping

    Science.gov (United States)

    Koselja, Michael P.; Kubelka, Jiri; Kvapil, Jiri

    1992-06-01

    Lamp pumping of Ti:Sapphire has some advantages over laser pumping and represents some interest due to possible applications. The paper will present laser behavior of Ti:Sapphire under very long lamp pulse pumping. Pulse lamp duration (FWHM) was more than 100 times greater than the lifetime of Ti3+. Output energy with no tuning element was achieved greater than 1.5 J with 0.12% electrical-to-optical efficiency. Dimensions of the rod used was 7 mm in diameter and 148 mm in length. The doping level of Ti3+ was 0.09% Ti2O3 in the rod. Tuning characteristics with different tuning elements are also presented. Further development to obtain CW lamp pumping operation will be discussed.

  13. A GRASP for Next Generation Sapphire Image Acquisition Scheduling

    Directory of Open Access Journals (Sweden)

    Yang Wang

    2016-01-01

    Full Text Available This paper investigates an image acquisition scheduling problem for a Canadian surveillance-of-space satellite named Sapphire that takes images of deep space Earth-orbiting objects. For a set of resident space objects (RSOs that needs to be imaged within the time horizon of one day, the Sapphire image acquisition scheduling (SIAS problem is to find a schedule that maximizes the “Figure of Merit” of all the scheduled RSO images. To address the problem, we propose an effective GRASP heuristic that alternates between a randomized greedy constructive procedure and a local search procedure. Experimental comparisons with the currently used greedy algorithm are presented to demonstrate the merit of the proposed algorithm in handling the SIAS problem.

  14. AlN growth on sapphire substrate by ammonia MBE

    Science.gov (United States)

    Mansurov, V. G.; Nikitin, A. Yu.; Galitsyn, Yu. G.; Svitasheva, S. N.; Zhuravlev, K. S.; Osvath, Z.; Dobos, L.; Horvath, Z. E.; Pecz, B.

    2007-03-01

    Kinetics of (0 0 0 1) Al 2O 3 surface nitridation and subsequent growth of AlN films on the sapphire substrate by ammonia molecular beam epitaxy (MBE) are investigated. Surface morphology evolution during AlN growth is studied in situ by reflection high energy electron diffraction and ex situ by atomic force microscopy. It is found that the surfaces of AlN layers thicker than 100 nm have two major features: a quite smooth background and noticeable amount of hillocks. The influence of growth conditions on the AlN surface morphology is studied in order to find a way for reducing of the hillocks density. A modification of nitridated sapphire surface by small amount of Al (1-2 monolayers) with subsequent treatment of the surface under ammonia flux is proposed. An improvement of AlN surface morphology of the layers grown on the modified surfaces is demonstrated.

  15. Measurements of prompt radiation induced conductivity of alumina and sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, E. Frederick [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Zarick, Thomas Andrew [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sheridan, Timothy J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Preston, Eric F. [ITT Coporation, Colorado Springs, CO (United States)

    2011-04-01

    We performed measurements of the prompt radiation induced conductivity in thin samples of Alumina and Sapphire at the Little Mountain Medusa LINAC facility in Ogden, UT. Five mil thick samples were irradiated with pulses of 20 MeV electrons, yielding dose rates of 1E7 to 1E9 rad/s. We applied variable potentials up to 1 kV across the samples and measured the prompt conduction current. Analysis rendered prompt conductivity coefficients between 1E10 and 1E9 mho/m/(rad/s), depending on the dose rate and the pulse width for Alumina and 1E7 to 6E7 mho/m/(rad/s) for Sapphire.

  16. Color Enhancement by Diffusion of Beryllium in Dark Blue Sapphire

    Institute of Scientific and Technical Information of China (English)

    Kyungj in Kim; Yongkil Ahn

    2016-01-01

    Diffusion of beryllium was performed on dark blue sapphire from China and Australia.The samples were heated with beryllium as a dopant in a furnace at 1 600 ℃ for 42 h in air.After beryllium diffusion,sam-ples were analyzed by UV-Vis,FTIR,and WD-XRF spectroscopy.After heat-treatment with Be as a catalyst, the irons of the ferrous state were changed to the ferric state.Therefore,reaction of Fe2+/Ti4+ IVCT was de-creased.The absorption peaks at 3 309 cm-1 attributed to OH radical were disappeared completely due to carry out heat treatment.Consequently,the intensity of absorption band was decreased in the visible region.Espe-cially,decreased absorption band in the vicinity of 570 nm was responsible for the lighter blue color.There-fore,we confirmed that the dark blue sapphires from China and Australia were changed to vivid blue.

  17. Ordered gold nanostructures on sapphire surfaces: Fabrication and optical investigations

    Energy Technology Data Exchange (ETDEWEB)

    Muslimov, A. E., E-mail: amuslimov@mail.ru; Butashin, A. V. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Konovko, A. A. [Moscow State University (Russian Federation); Smirnov, I. S. [Moscow State University of Electronics and Mathematics (Russian Federation); Roshchin, B. S.; Volkov, Yu. O. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Angelutz, A. A.; Andreev, A. V.; Shkurinov, A. P. [Moscow State University (Russian Federation); Kanevskii, V. M.; Asadchikov, V. E. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2012-05-15

    The possibilities of obtaining ordered gold nanoarrays on sapphire surfaces with oriented nanorelief are demonstrated. The structures are morphologically described using atomic force microscopy data. A study of the angular dependence of the reflectivity in the visible range of electromagnetic waves has revealed some features which are likely to indicate surface plasmon-polariton excitation at the air-gold interface under exposure to p-polarized radiation. The experimental results are found to be in good agreement with the theoretical calculations.

  18. Route to 100 TW Ti: Sapphire laser at repetitive mode

    Directory of Open Access Journals (Sweden)

    Teng Hao

    2013-11-01

    Full Text Available We demonstrated a 100 TW-class femtosecond Ti: sapphire laser running at repetition rate of 0.1 Hz by adding a stage amplifier in the 20 TW/10 Hz laser facility (XL-II. Pumping the new stage amplifier with the 25 J green Nd:glass laser, we successfully upgraded the laser energy to 3.4 J with duration of 29 fs, corresponding to a peak power of 117 TW.

  19. The Problem of using Quartz as a radiation dosimeter: fundamentals of dose dependence

    Science.gov (United States)

    King, G. E.; Finch, A. A.; Robinson, R. A. J.; Hole, D. E.

    2009-04-01

    Quartz is widely used as a radiation dosimeter in Quaternary geomorphological and archaeological dating applications through Optically Stimulated Luminescence (over 1,200 journal publications since 2000). However, obtaining an accurate equivalent radiation dose (DE) can be challenging, especially where the luminescence intensity of the quartz is dim. The causes of variation in luminescence intensity between quartz grains of different provenances, transport and thermal histories is unknown, however it has been suggested that it relates to either the dosimetric history of the grain, or mechanical processes which occur in transit. Investigation of the fundamental properties of the luminescence of quartz, enables investigation of dose dependent changes in luminescence intensity. A series of dose dependence experiments were conducted using spectroscopic ionoluminescence, which comprises the excitation of quartz with protons accelerated at 0.95 MeV. The energy delivered to the sample throughout ion implantation is similar to that received during gamma irradiation, and thus approximates sample radiation dosing. A natural macro-crystal of α-quartz was investigated parallel and perpendicular to c, to observe any orientation dependent effects, as well as a calibration quartz from the Risø National Laboratory, Denmark, and a Scottish geomorphological sample, prepared using standard laboratory procedures. The calibration quartz sample has excellent luminescence intensity and is suited to analysis using the single-aliquot regenerative dose (SAR) standard OSL protocol, the Scottish sample alternatively has very dim luminescence and exhibits variable behaviour when analysed with SAR. Despite the differences between the luminescence behaviour of the samples, all three responded to the dose dependence experiments in a similar manner. The UV/blue emission was observed to deplete with increasing dose, whereas the red emission, not normally analysed within OSL, exhibited increased

  20. SINGLE-CRYSTAL SAPPHIRE OPTICAL FIBER SENSOR INSTRUMENTATION

    Energy Technology Data Exchange (ETDEWEB)

    A. Wang; G. Pickrell; R. May

    2002-09-10

    Accurate measurement of temperature is essential for the safe and efficient operation and control of a wide range of industrial processes. Appropriate techniques and instrumentation are needed depending on the temperature measurement requirements in different industrial processes and working environments. Harsh environments are common in many industrial applications. These harsh environments may involve extreme physical conditions, such as high-temperature, high-pressure, corrosive agents, toxicity, strong electromagnetic interference, and high-energy radiation exposure. Due to these severe environmental conditions, conventional temperature sensors are often difficult to apply. This situation has opened a new but challenging opportunity for the sensor society to provide robust, high-performance, and cost-effective temperature sensors capable of operating in those harsh environments. The focus of this research program has been to develop a temperature measurement system for temperature measurements in the primary and secondary stages of slagging gasifiers. For this application the temperature measurement system must be able to withstand the extremely harsh environment posed by the high temperatures and corrosive agents present in these systems. Real-time, accurate and reliable monitoring of temperature for the coal gasification process is important to realize the full economic potential of these gasification systems. Long life and stability of operation in the high temperature environment is essential for the temperature measurement system to ensure the continuous running of the coal gasification system over the long term. In this high temperature and chemically corrosive environment, rather limited high temperature measurement techniques such as high temperature thermocouples and optical/acoustic pyrometers are available, each with their own limitations. In this research program, five different temperature sensing schemes based on the single crystal sapphire

  1. Gold volatile species atomization and preconcentration in quartz devices for atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Arslan, Yasin [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic); Mehmet Akif Ersoy University, Faculty of Arts & Sciences, Chemistry Department, 15030 Burdur (Turkey); Musil, Stanislav; Matoušek, Tomáš; Kratzer, Jan [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic); Dědina, Jiří, E-mail: dedina@biomed.cas.cz [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic)

    2015-01-01

    The on-line atomization of gold volatile species was studied and the results were compared with thermodynamic calculations in several quartz atomizers, namely: diffusion flame, flame-in-gas-shield, flame-in-plain-tube, externally heated T-tube and externally heated flame-in-T-tube. Atomization mechanism in the explored devices is proposed, where volatile species are converted to thermodynamically stable AuH at elevated temperature over 500 °C and then atomized by an interaction with a cloud of hydrogen radicals. Because of its inherent simplicity and robustness, diffusion flame was employed as a reference atomizer. It yielded atomization efficiency of 70 to 100% and a very good long time reproducibility of peak area sensitivity: 1.6 to 1.8 s μg{sup −1}. Six and eleven times higher sensitivity, respectively, was provided by atomizers with longer light paths in the observation volume, i.e. externally heated T-tube and externally heated flame-in-T-tube. The latter one, offering limit of detection below 0.01 μg ml{sup −1}, appeared as the most prospective for on-line atomization. Insight into the mechanism of atomization of gold volatile species, into the fate of free atoms and into subsequent analyte transfer allowed to assess possibilities of in-atomizer preconcentration of gold volatile species: it is unfeasible with quartz atomizers but a sapphire tube atomizer could be useful in this respect. - Highlights: • On-line atomization of gold volatile species for AAS in quartz devices was studied. • Atomization mechanism was proposed and atomization efficiency was estimated. • Possibilities of in-atomizer preconcentration of gold volatile species were assessed.

  2. Electron-beam irradiation effects on luminescence properties in subsurface regions of single-crystalline sapphires treated with and without hydrogen plasma exposures

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bo-Hyun [Department of Electrical Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)]. E-mail: bhlee@daiyan.eei.eng.osaka-u.ac.jp; Ito, Toshimichi [Department of Electrical Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2007-10-15

    Electron irradiation effects on various insulating sapphires treated with and without hydrogen plasma have been investigated mainly by means of cathodoluminescence (CL) measurements. The samples examined included Be-diffusion-treated natural sapphire (BNS) and two types of synthetic sapphires grown by Verneuil and Czochralski methods. For all the samples examined, on one hand, their CL intensities of the F{sup +}-center-related emission peaked at {approx}3.8 eV rapidly increased with increasing the fluences of keV electrons, and were represented roughly by exponentially saturating curves. There occurred slight blue-shifts of the F{sup +}-center luminescence other than the intensity increases for some of the electron-irradiated specimens, suggesting possible presence of two components for the F{sup +}-center luminescence. On the other hand, a hydrogen plasma exposure to these sapphires resulted in sample-dependent changes in the optical property and in the beam-irradiation effect on the F{sup +}-center CL emission. Such variations were induced most strongly in the BNS sample, whose color changed from orange to pink due to substantial decreases in the absorbance after the hydrogen plasma treatment. Furthermore, the energy positions of both the Cr{sup 3+}-center luminescence peaked at {approx}1.8 eV and its satellite peaks were found to slightly shift for the untreated and H-plasma-treated BNS samples after the electron beam irradiations. Possible origins of these observations are discussed.

  3. Epitaxial growth of ZnO on quartz substrate by sol-gel spin-coating method

    Science.gov (United States)

    Chebil, W.; Boukadhaba, M. A.; Fouzri, A.

    2016-07-01

    ZnO thin films grown on Quartz substrates using sol-gel method were synthesized and annealing at different temperature (700 °C, 900 °C and 1000 °C). The structural, optical and morphological comparison of ZnO layers elaborated with that obtained by the sophisticated and expensive technique MOCVD demonstrates the success of the ZnO epitaxial growth on quartz substrate by sol-gel process. Sol-gel ZnO film deposited on quartz substrate annealed at 1000 °C exhibit only (00l) XRD peak which is similar to the diffraction patterns of epitaxial ZnO grown on sapphire by MOCVD. The Surface morphology was examined by SEM which revealed that the grain size becomes larger and faceted as increasing annealing temperature. Pl emission peak of sol-gel ZnO annealed at 1000 °C revealed a close similarity with that obtained by MOCVD ZnO but with a weaker intensity.

  4. Leveraging Python Interoperability Tools to Improve Sapphire's Usability

    Energy Technology Data Exchange (ETDEWEB)

    Gezahegne, A; Love, N S

    2007-12-10

    The Sapphire project at the Center for Applied Scientific Computing (CASC) develops and applies an extensive set of data mining algorithms for the analysis of large data sets. Sapphire's algorithms are currently available as a set of C++ libraries. However many users prefer higher level scripting languages such as Python for their ease of use and flexibility. In this report, we evaluate four interoperability tools for the purpose of wrapping Sapphire's core functionality with Python. Exposing Sapphire's functionality through a Python interface would increase its usability and connect its algorithms to existing Python tools.

  5. Ga/Mg ratio as a new geochemical tool to differentiate magmatic from metamorphic blue sapphires

    Science.gov (United States)

    Peucat, J. J.; Ruffault, P.; Fritsch, E.; Bouhnik-Le Coz, M.; Simonet, C.; Lasnier, B.

    2007-10-01

    Using ICP-MS-LA analyses, we demonstrate that the use of the Ga/Mg ratio, in conjunction with the Fe concentration, is an efficient tool in discriminating between "metamorphic" and "magmatic" blue sapphires. Magmatic blue sapphires found in alkali basalts (e.g. southeastern Asia, China, Africa) are commonly medium-rich to rich in Fe (with average contents between 2000 and 11000 ppm), high in Ga (> 140 ppm), and low in Mg (generally 10). Conversely, metamorphic blue sapphires found in basalts (e.g. Pailin pastel) and in metamorphic terrains (e.g. Mogok, Sri Lanka, Ilakaka) are characterized by low average iron contents ( 60 ppm) with low average Ga/Mg ratios (< 10). Basaltic magmatic sapphires have Fe, Ga and Mg contents similar to those obtained for primary magmatic sapphires found in the Garba Tula syenite. This suggests that these both sets of sapphires have a possible common "syenitic" origin, as previously proposed from other criteria. In addition, plumasite-related sapphires and metamorphic sapphires also exhibit similar composition in trace elements. Based on results from the present study, we suggest that fluid circulations during a metamorphic stage produced metasomatic exchanges between mafic and acidic rocks (plumasite model), thus explaining the high Mg contents and converging Ga/Mg ratios observed in metamorphic sapphires.

  6. Looking at Dauphiné twins in vein quartz as a potential paleostress indicator

    Science.gov (United States)

    Sintubin, Manuel; Wenk, Hans-Rudolf

    2013-04-01

    Paleostress studies commonly call upon (1) a fault slip data inversion technique, (2) a calcite twin stress inversion technique, (3) recrystallized grain size piezometry for quartz, or (4) direct measurements of residual lattice strain. Recent advances in orientation imaging microscopy (OIM) using electron backscatter diffraction (EBSD) on a scanning electron microscope (SEM) have revealed that Dauphiné twinning is very common in quartz in naturally deformed quartz-bearing rocks in a wide range of tectonometamorphic conditions. It has long been known that mechanical Dauphiné twinning in quartz can be stress-induced. Based on the results of an extensive EBSD-OIM analysis on vein quartz, taken from well-studied early to late-orogenic veins in the High-Ardenne slate belt (Germany, Belgium), we explore the potential use of mechanical Dauphiné twins as a paleostress indicator, possibly completing our toolbox for reconstructing paleostresses in the Earth's crust. The vein quartz studied precipitated in low-grade tectonometamorphic conditions (~200-400°C), typical for the brittle-plastic transition zone at the base of the seismogenic crust (~7-15km). Quartz has only been weakly affected by low to moderate temperature (200 to 400°C) crystal-plastic deformation. The samples show grains with a high concentration of Dauphiné twin boundaries and others free of twin boundaries, thus being untwinned or completely twinned. This pattern depends on the crystallographic orientation. Twin boundaries are arrested by grain or subgrain boundaries, suggesting that Dauphiné twinning occurred on a pre-existing fabric that resulted from crystal-plastic deformation. An analysis of the orientation distribution of the rhombs in the twinned variant domains of individual quartz (sub-)grains reveals a particular preferred orientation of the poles to rhombs. We will discuss the possible significance of these observations with respect to paleostresses that may have caused the mechanical

  7. Thermal activation of OSL as a geothermometer for quartz grain heating during fault movements

    Energy Technology Data Exchange (ETDEWEB)

    Rink, W.J.; Toyoda, S.; Rees-Jones, J.; Schwarcz, H.P. [School of Geography and Geology, McMaster University, Hamilton, ON (Canada)

    1999-02-01

    In discussions of ESR dating of fault movements, there has been much debate whether zeroing of ESR signals is a mechanical shearing effect or caused by frictional heating. The OSL (optically stimulated luminescence) sensitivity of quartz is known to increase after heating. This thermal activation of dose response of the OSL in quartz should be useful as a geothermometer to test whether quartz particles in fault gouge had been heated. We tested the OSL sensitivities of quartz from fault gouge, and from a control (quartz grains from sandstone) and were able to show heat-induced enhancement of OSL sensitivity to a test dose. We observed that relative enhancement of OSL dose response (ratio of heated to unheated single aliquots) is significantly less for the finest grains (45-75 and 100-150 {mu}m) compared with coarser grains (150-250 {mu}m). These data are consistent with a model of zeroing of the quartz grains during faulting, by frictional heating localized to the grain boundaries, which would be expected to affect smaller grains more than large ones. This argues against a zeroing model in which the entire fault gouge is heated by friction. Higher laboratory preheating of sandstone quartz reduces between-aliquot variability of OSL dose response in the unheated grains to nearly zero. Unheated coarsest fault gouge grains displayed virtually no among-aliquot variability, whereas fine grains showed much larger between-aliquot variability; as with the quartz sand, variability dropped to near zero after laboratory heating, suggesting that fine grains in fault gouge have experienced a wide range of natural thermal histories during faulting. This may present a problem for ESR dating of fault gouge using the plateau method.

  8. Creep of quartz by dislocation and grain boundary processes

    Science.gov (United States)

    Fukuda, J. I.; Holyoke, C. W., III; Kronenberg, A. K.

    2015-12-01

    Wet polycrystalline quartz aggregates deformed at temperatures T of 600°-900°C and strain rates of 10-4-10-6 s-1 at a confining pressure Pc of 1.5 GPa exhibit plasticity at low T, governed by dislocation glide and limited recovery, and grain size-sensitive creep at high T, governed by diffusion and sliding at grain boundaries. Quartz aggregates were HIP-synthesized, subjecting natural milky quartz powder to T=900°C and Pc=1.5 GPa, and grain sizes (2 to 25 mm) were varied by annealing at these conditions for up to 10 days. Infrared absorption spectra exhibit a broad OH band at 3400 cm-1 due to molecular water inclusions with a calculated OH content (~4000 ppm, H/106Si) that is unchanged by deformation. Rate-stepping experiments reveal different stress-strain rate functions at different temperatures and grain sizes, which correspond to differing stress-temperature sensitivities. At 600-700°C and grain sizes of 5-10 mm, flow law parameters compare favorably with those for basal plasticity and dislocation creep of wet quartzites (effective stress exponents n of 3 to 6 and activation enthalpy H* ~150 kJ/mol). Deformed samples show undulatory extinction, limited recrystallization, and c-axis maxima parallel to the shortening direction. Similarly fine-grained samples deformed at 800°-900°C exhibit flow parameters n=1.3-2.0 and H*=135-200 kJ/mol corresponding to grain size-sensitive Newtonian creep. Deformed samples show some undulatory extinction and grain sizes change by recrystallization; however, grain boundary deformation processes are indicated by the low value of n. Our experimental results for grain size-sensitive creep can be compared with models of grain boundary diffusion and grain boundary sliding using measured rates of silicon grain boundary diffusion. While many quartz mylonites show microstructural and textural evidence for dislocation creep, results for grain size-sensitive creep may apply to very fine-grained (<10 mm) quartz mylonites.

  9. Estimating Quartz Reserves Using Compositional Kriging

    Directory of Open Access Journals (Sweden)

    J. Taboada

    2013-01-01

    Full Text Available The aim of this study was to determine spatial distribution and volume of four commercial quartz grades, namely, silicon metal, ferrosilicon, aggregate, and kaolin (depending on content in impurities in a quartz seam. The chemical and mineralogical composition of the reserves in the seam were determined from samples collected from outcrops, blasting operations, and exploratory drilling, and compositional kriging was used to calculate the volume and distribution of the reserves. A more accurate knowledge of the deposit ensures better mine planning, leading to higher profitability and an improved relationship with the environment.

  10. Using soils for accident dosimetry: a preliminary study using optically stimulated luminescence from quartz

    DEFF Research Database (Denmark)

    Fujita, Hiroki; Jain, Mayank; Murray, Andrew S.

    2011-01-01

    The optimum conditions of preheat temperature, stimulation temperature, etc. in the single-aliquot regenerative optically stimulated luminescence (SAR OSL) method were examined specifically for measuring background dose in natural quartz extracted from soils collected around Tokai-mura in Japan....... The objective was to assess the potential of SAROSL dosimetry using soils for retrospective assessment of a radiation accident. Variation in dose with depth was also measured. The SAR data showed good reproducibility and dose recovery, and there was no evidence of fading of the quartz signal based on “delayed......, and no clear trend in dose depth profile was observed. From these results, we conclude that SAR OSL dosimetry using natural quartz extracted from soil could be used to evaluate the dose of an accident....

  11. Data Acquisition System for Quartz Crystal Microbalances

    Directory of Open Access Journals (Sweden)

    Kleber Romero Felizardo

    2006-02-01

    Full Text Available This work presents a data acquisition system used in a mass sensor: quartz crystal microbalance. This system reads the frequency of this sensor along the time and sends the collected data to the computer through a serial interface.

  12. Bubble Formation in Silicon-Quartz Interface

    OpenAIRE

    Kakimoto, K.; EGUCHI, M.; Ozoe, H.

    1997-01-01

    Bubble formation at an interface between silicon melt and a quartz crucible was studied by thermodynamical calculation and visualization of bubble formation using X-ray radiography. A phase diagram of silicon-oxygen (Si-O) system is also calculated from the reported thermodynamical data. Critical temperature and radius of bubble formation at the interface was discussed.

  13. Time-resolved luminescence from quartz

    NARCIS (Netherlands)

    Chithambo, M.L.; Ankjærgaard, C.; Pagonis, V.

    2016-01-01

    Time-resolved optical stimulation of luminescence has become established as a key method for measurement of optically stimulated luminescence from quartz, feldspar and α-Al2O3:C, all materials of interest in dosimetry. The aim of time-resolved optical stimulation is to separ

  14. Thermal Control of a Dual Mode Parametric Sapphire Transducer

    CERN Document Server

    Belfi, Jacopo; De Michele, Andrea; Gabbriellini, Gianluca; Mango, Francesco; Passaquieti, Roberto

    2010-01-01

    We propose a method to control the thermal stability of a sapphire dielectric transducer made with two dielectric disks separated by a thin gap and resonating in the whispering gallery (WG) modes of the electromagnetic field. The simultaneous measurement of the frequencies of both a WGH mode and a WGE mode allows one to discriminate the frequency shifts due to gap variations from those due to temperature instability. A simple model, valid in quasi equilibrium conditions, describes the frequency shift of the two modes in terms of four tuning parameters. A procedure for the direct measurement of them is presented.

  15. Ultrafast, ultrahigh-peak power Ti:sapphire laser system

    Energy Technology Data Exchange (ETDEWEB)

    Yamakawa, Koichi; Aoyama, Makoto; Matsuoka, Shinichi; Akahane, Yutaka; Kase, Teiji; Nakano, Fumihiko; Sagisaka, Akito [Advanced Photon Research Center, Kansai Research Establishment, Japan Atomic Energy Research Inst., Kizu, Kyoto (Japan)

    2001-01-01

    We review progress in the generation of multiterawatt optical pulses in the 10-fs range. We describe a design, performance and characterization of a Ti:sapphire laser system based on chirped-pulse amplification, which has produced a peak power in excess of 100-TW with sub-20-fs pulse durations and an average power of 19-W at a 10-Hz repetition rate. We also discuss extension of this system to the petawatt power level and potential applications in the relativistic, ultrahigh intensity regimes. (author)

  16. Lattice-Matched Semiconductor Layers on Single Crystalline Sapphire Substrate

    Science.gov (United States)

    Choi, Sang; King, Glen; Park, Yeonjoon

    2009-01-01

    SiGe is an important semiconductor alloy for high-speed field effect transistors (FETs), high-temperature thermoelectric devices, photovoltaic solar cells, and photon detectors. The growth of SiGe layer is difficult because SiGe alloys have different lattice constants from those of the common Si wafers, which leads to a high density of defects, including dislocations, micro-twins, cracks, and delaminations. This innovation utilizes newly developed rhombohedral epitaxy of cubic semiconductors on trigonal substrates in order to solve the lattice mismatch problem of SiGe by using trigonal single crystals like sapphire (Al2O3) as substrate to give a unique growth-orientation to the SiGe layer, which is automatically controlled at the interface upon sapphire (0001). This technology is different from previous silicon on insulator (SOI) or SGOI (SiGe on insulator) technologies that use amorphous SiO2 as the growth plane. A cubic semiconductor crystal is a special case of a rhombohedron with the inter-planar angle, alpha = 90 deg. With a mathematical transformation, all rhombohedrons can be described by trigonal crystal lattice structures. Therefore, all cubic lattice constants and crystal planes (hkl) s can be transformed into those of trigonal crystal parameters. These unique alignments enable a new opportunity of perfect lattice matching conditions, which can eliminate misfit dislocations. Previously, these atomic alignments were thought to be impossible or very difficult. With the invention of a new x-ray diffraction measurement method here, growth of cubic semiconductors on trigonal crystals became possible. This epitaxy and lattice-matching condition can be applied not only to SiGe (111)/sapphire (0001) substrate relations, but also to other crystal structures and other materials, including similar crystal structures which have pointgroup rotational symmetries by 120 because the cubic (111) direction has 120 rotational symmetry. The use of slightly miscut (less than

  17. Adsorption and Removal of Organic Dye at Quartz Sand-Water Interface

    Directory of Open Access Journals (Sweden)

    Jada A.

    2013-11-01

    Full Text Available We studied the transport, sorption and desorption of organic cation (Methylene Blue, MB through a porous medium consisting of quartz sand particles negatively charged. We examined various parameters such as the ionic strength of the aqueous solution, the flow velocity, the pH of the aqueous phase, the temperature of the medium and the nature of the divalent metal cations present in solution, which affect the transport and the deposition of MB through the porous medium. Step-input experiments were carried out to measure the dye retention. The data showed a decrease in the MB adsorbed amount on the quartz, when the pH of the aqueous phase, or the temperature, decreases, or when the flow rate, or the affinity of the divalent cation (Ca2+, Cu2+, Zn2+ and Ba2+ toward the quartz surface increases. The increase in ionic strength leads to a small decrease in the MB adsorbed amount. However, the increase in temperature leads to an increase in the retained MB amount, which suggests that the adsorption of MB on the surface of quartz is endothermic in nature. The overall data indicate that, at ambient temperature, electrostatic interaction forces, which occur between the cationic organic pollutant and the negative surface of the quartz substrate, mainly control the adsorption process.

  18. Identifying well-bleached quartz using the different bleaching rates of quartz and feldspar luminescence signals

    DEFF Research Database (Denmark)

    Murray, A.S.; Thomsen, Kristina Jørkov; Masuda, N.;

    2012-01-01

    When dating older sedimentary deposits using quartz, there are no unambiguous methods for identifying the presence of incomplete bleaching. Current statistical analysis of dose distributions depends entirely on the assumption that incomplete bleaching and mixing are the main causes of any excess...... in relative bleaching rates of quartz optically stimulated luminescence (OSL) and feldspar luminescence stimulated at 50 °C by infrared light (IR50) and feldspar luminescence stimulated at 290 °C by infrared light after a stimulation at 50 °C (pIRIR290), and use recently deposited samples to determine...... that the large aliquot data are more likely to be correct. We conclude that a comparison of quartz and feldspar doses provides a useful independent method for identifying well-bleached quartz samples, and that it is unwise to apply statistical models to dose distributions without clear evidence for the physical...

  19. Flashlamp pumped Ti-sapphire laser for ytterbium glass chirped pulse amplification

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Akihiko; Ohzu, Akira; Sugiyama, Akira [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    1998-03-01

    A flashlamp pumped Ti:sapphire laser is designed for ytterbium glass chirped pulse amplification. A high quality Ti:sapphire rod and a high energy long pulse discharging power supply are key components. The primary step is to produce the output power of 10 J per pulse at 920 nm. (author)

  20. Ti:sapphire rib channel waveguide fabricated by reactive ion etching of a planar waveguide

    NARCIS (Netherlands)

    Crunteanu, A.; Jänchen, G.; Salathé, R.P.; Hoffmann, P.; Pollnau, M.; Eason, R.W.; Shepherd, D.P.

    2002-01-01

    We were successful in creating 1.4-µm high ribs in a Ti:sapphire planar waveguide by reactive ion etching. Optical investigations of the obtained structure showed channel-waveguide fluorescence emission of the Ti:sapphire layer after Ar-ion excitation.

  1. Fiber-laser-pumped Ti:sapphire laser

    CERN Document Server

    Samanta, G K; Devi, Kavita; Ebrahim-Zadeh, M

    2010-01-01

    We report the first experimental demonstration of efficient and high-power operation of a Ti:sapphire laser pumped by a simple, compact, continuous-wave (cw) fiber-laser-based green source. The pump radiation is obtained by direct single-pass second-harmonic-generation (SHG) of a 33-W, cw Yb-fiber laser in 30-mm-long MgO:sPPLT crystal, providing 11 W of single-frequency green power at 532 nm in TEM00 spatial profile with power and frequency stability better than 3.3% and 32 MHz, respectively, over one hour. The Ti:sapphire laser is continuously tunable across 743-970 nm and can deliver an output power up to 2.7 W with a slope efficiency as high as 32.8% under optimum output coupling of 20%. The laser output has a TEM00 spatial profile with M2<1.44 across the tuning range and exhibits a peak-to-peak power fluctuation below 5.1% over 1 hour.

  2. Temperature behavior of damage in sapphire implanted with light ions

    Energy Technology Data Exchange (ETDEWEB)

    Alves, E. [Ion Beam Laboratory, Instituto Tecnologico e Nuclear, Sacavem 2686-953 (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Lisbon (Portugal)], E-mail: ealves@itn.pt; Marques, C. [Ion Beam Laboratory, Instituto Tecnologico e Nuclear, Sacavem 2686-953 (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Lisbon (Portugal); Safran, G. [Research Institute for Technical Physics and Materials Science, H-1525 Budapest (Hungary); McHargue, Carl J. [University of Tennessee, Knoxville, TN 37996-0750 (United States)

    2009-05-01

    In this study, we compare and discuss the defect behavior of sapphire single crystals implanted with different fluences (1 x 10{sup 16}-1 x 10{sup 17} cm{sup -2}) of carbon and nitrogen with 150 keV. The implantation temperatures were RT, 500 deg. C and 1000 deg. C to study the influence of temperature on the defect structures. For all the ions the Rutherford backscattering-channeling (RBS-C) results indicate a surface region with low residual disorder in the Al-sublattice. Near the end of range the channeled spectrum almost reaches the random indicating a high damage level for fluences of 1 x 10{sup 17} cm{sup -2}. The transmission electron microscopy (TEM) photographs show a layered contrast feature for the C implanted sample where a buried amorphous region is present. For the N implanted sample the Electron Energy Loss Spectroscopy (EELS) elemental mapping give evidence for the presence of a buried damage layer decorated with bubbles. Samples implanted at high temperatures (500 deg. C and 1000 deg. C) show a strong contrast fluctuation indicating a defective crystalline structure of sapphire.

  3. The effect of crystal orientation on the cryogenic strength of hydroxide catalysis bonded sapphire

    Science.gov (United States)

    Haughian, K.; Douglas, R.; van Veggel, A. A.; Hough, J.; Khalaidovski, A.; Rowan, S.; Suzuki, T.; Yamamoto, K.

    2015-04-01

    Hydroxide catalysis bonding has been used in gravitational wave detectors to precisely and securely join components of quasi-monolithic silica suspensions. Plans to operate future detectors at cryogenic temperatures has created the need for a change in the test mass and suspension material. Mono-crystalline sapphire is one candidate material for use at cryogenic temperatures and is being investigated for use in the KAGRA detector. The crystalline structure of sapphire may influence the properties of the hydroxide catalysis bond formed. Here, results are presented of studies of the potential influence of the crystal orientation of sapphire on the shear strength of the hydroxide catalysis bonds formed between sapphire samples. The strength was tested at approximately 8 K; this is the first measurement of the strength of such bonds between sapphire at such reduced temperatures. Our results suggest that all orientation combinations investigated produce bonds of sufficient strength for use in typical mirror suspension designs, with average strengths >23 MPa.

  4. Millimeter And Submillimeter-Wave Integrated Circuits On Quartz

    Science.gov (United States)

    Mehdi, Imran; Mazed, Mohammad; Siegel, Peter; Smith, R. Peter

    1995-01-01

    Proposed Quartz substrate Upside-down Integrated Device (QUID) relies on UV-curable adhesive to bond semiconductor with quartz. Integrated circuits including planar GaAs Schottky diodes and passive circuit elements (such as bandpass filters) fabricated on quartz substrates. Circuits designed to operate as mixers in waveguide circuit at millimeter and submillimeter wavelengths. Integrated circuits mechanically more robust, larger, and easier to handle than planar Schottky diode chips. Quartz substrate more suitable for waveguide circuits than GaAs substrate.

  5. Electronic structure analysis of GaN films grown on r- and a-plane sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Monu; Krishna TC, Shibin; Aggarwal, Neha [Physics of Energy Harvesting Division, CSIR-National Physical Laboratory (CSIR-NPL), Dr. K.S. Krishnan Marg, New Delhi 110012 (India); Academy of Scientific and Innovative Research (AcSIR), CSIR-NPL Campus, Dr. K.S. Krishnan Marg, New Delhi 110012 (India); Vihari, Saket [Physics of Energy Harvesting Division, CSIR-National Physical Laboratory (CSIR-NPL), Dr. K.S. Krishnan Marg, New Delhi 110012 (India); Gupta, Govind, E-mail: govind@nplindia.org [Physics of Energy Harvesting Division, CSIR-National Physical Laboratory (CSIR-NPL), Dr. K.S. Krishnan Marg, New Delhi 110012 (India); Academy of Scientific and Innovative Research (AcSIR), CSIR-NPL Campus, Dr. K.S. Krishnan Marg, New Delhi 110012 (India)

    2015-10-05

    Graphical abstract: Substrate orientation induced changes in surface chemistry, band bending, hybridization states, electronic properties and surface morphology of epitaxially grown GaN were investigated via photoemission spectroscopic and Atomic Force Microscopic measurements. - Highlights: • Electronic structure and surface properties of GaN film grown on r/a-plane sapphire. • Downward band bending (0.5 eV) and high surface oxide is observed for GaN/a-sapphire. • Electron affinity and ionization energy is found to be higher for GaN/a-sapphire. - Abstract: The electronic structure and surface properties of epitaxial GaN films grown on r- and a-plane sapphire substrates were probed via spectroscopic and microscopic measurements. X-ray photoemission spectroscopic (XPS) measurements were performed to analyse the surface chemistry, band bending and valence band hybridization states. It was observed that GaN/a-sapphire display a downward band bending of 0.5 eV and possess higher amount of surface oxide compared to GaN/r-sapphire. The valence band (VB) investigation revealed that the hybridization corresponds to the interactions of Ga 4s and Ga 4p orbitals with N 2p orbital, and result in N2p–Ga4p, N2p–Ga4s{sup ∗}, mixed and N2p–Ga4s states. The energy band structure and electronic properties were measured via ultraviolet photoemission spectroscopic (UPS) experiments. The band structure analysis and electronic properties calculations divulged that the electron affinity and ionization energy of GaN/a-sapphire were 0.3 eV higher than GaN/r-sapphire film. Atomic Force Microscopic (AFM) measurements revealed faceted morphology of GaN/r-sapphire while a smooth pitted surface was observed for GaN/a-sapphire film, which is closely related to surface oxide coverage.

  6. Emission polarization study on quartz and calcite.

    Science.gov (United States)

    Vincent, R. K.

    1972-01-01

    Calculation of the spectral emission polarization of quartz and calcite polished plates for observation angles of 20 and 70 deg by the substitution of complex index of refraction values for each mineral into Fresnel's equations. The emission polarization is shown to be quite wavelength-dependent, demonstrating that selected narrow or medium-width spectral bands exhibit a significantly higher percentage of polarization than a broad spectral band for these two minerals. Field measurements with a broadband infrared radiometer yield polarizations on the order of 2% for a coarse-grained granite rock and beach sand (both quartz-rich). This implies that a more sensitive detector with a selected medium-width filter may be capable of measuring emission polarization accurately enough to make this parameter useful as a remote sensing tool for discrimination among rocks on the basis of texture.

  7. Axiomatic Design of Micro Quartz Rate Sensor

    Institute of Scientific and Technical Information of China (English)

    SHI Yang-he; ZHANG Hong-hai; LIU Sheng

    2007-01-01

    Quartz rate sensors (QRS) made out of one single piece of quartz crystal are inertial devices which can be used for general rate control, stabilization, automotive and aerospace/defense markets,etc. The mechanical design of the QRS has been investigated based on axiomatic design. The axiomatic design matrix of the mechanical structure of Coriolis Vibratory Gyroscopes (CVG) has been proposed. The mechanical function of QRS is divided into three Function Requirements ( FR ) , i. e. , FR1 is the drive mode, FR2 is the sense mode, FR3 is a coupled connection where the Coriolis force can couple the two modes with a term proportional to the rotational rate. A new QRS which is easy to be fabricated has been put forward. Furthermore, the new QRS indicated that the axiomatic design is a help to functional design of products.

  8. Optically stimulated luminescence from quartz measured using the linear modulation technique

    DEFF Research Database (Denmark)

    Bulur, E.; Bøtter-Jensen, L.; Murray, A.S.

    2000-01-01

    The optically stimulated luminescence (OSL) from heated natural quartz has been investigated using the linear modulation technique (LMT), in which the excitation light intensity is increased linearly during stimulation. In contrast to conventional stimulation, which usually produces a monotonically...... stimulated component occurs at a shorter time. This allows the separation of the overlapping OSL components, which are assumed to originate from different traps. The LM-OSL curve from quartz shows an initial peak Followed by a broad one. Deconvolution using curve fitting has shown that the composite OSL...... curve from quartz can be approximated well by using a linear combination of first-order peaks. In addition to the three known components, i.e. fast, medium and slow components from continuous-wave-OSL studies, an additional slow component is also identified for the first time. The dose responses...

  9. Radiation on luminescent properties of quartz glasses and fiber light pipes

    CERN Document Server

    Abdurakhmanov, B S; Gulamova, R R; Alimov, R; Yuldashev, B S; Ashurov, M K; Rustamov, I R

    2002-01-01

    Paper contains the results of investigation into X-ray luminescence of KI and KU-1 quartz glasses and of various composition and size quartz fiber light pipes (FLP) gamma-irradiated within 10 sup 2 -10 sup 7 Gy dose range. On the basis of analysis of X-ray luminescence spectra of glasses and FLP and comparison of the experimental data one detected in spectra two luminescence bands within 410, 450-470 nm range. One determined dose dependences of X-ray luminescence intensity of every of these bands of luminescence and hypothesized about the nature of the relevant centers. The protective role of OH-groups in the process of radiation-induced generation of luminescence centres under gamma-irradiation of quartz glasses and FLP was confirmed experimentally

  10. High-Precision Hysteresis Sensing of the Quartz Crystal Inductance-to-Frequency Converter.

    Science.gov (United States)

    Matko, Vojko; Milanović, Miro

    2016-06-28

    A new method for the automated measurement of the hysteresis of the temperature-compensated inductance-to-frequency converter with a single quartz crystal is proposed. The new idea behind this method is a converter with two programmable analog switches enabling the automated measurement of the converter hysteresis, as well as the temperature compensation of the quartz crystal and any other circuit element. Also used is the programmable timing control device that allows the selection of different oscillating frequencies. In the proposed programmable method two different inductances connected in series to the quartz crystal are switched in a short time sequence, compensating the crystal's natural temperature characteristics (in the temperature range between 0 and 50 °C). The procedure allows for the measurement of the converter hysteresis at various values of capacitance connected in parallel with the quartz crystal for the converter sensitivity setting at selected inductance. It, furthermore, enables the measurement of hysteresis at various values of inductance at selected parallel capacitance (sensitivity) connected to the quartz crystal. The article shows that the proposed hysteresis measurement of the converter, which converts the inductance in the range between 95 and 100 μH to a frequency in the range between 1 and 200 kHz, has only 7 × 10(-13) frequency instability (during the temperature change between 0 and 50 °C) with a maximum 1 × 10(-11) hysteresis frequency difference.

  11. High-Precision Hysteresis Sensing of the Quartz Crystal Inductance-to-Frequency Converter

    Directory of Open Access Journals (Sweden)

    Vojko Matko

    2016-06-01

    Full Text Available A new method for the automated measurement of the hysteresis of the temperature-compensated inductance-to-frequency converter with a single quartz crystal is proposed. The new idea behind this method is a converter with two programmable analog switches enabling the automated measurement of the converter hysteresis, as well as the temperature compensation of the quartz crystal and any other circuit element. Also used is the programmable timing control device that allows the selection of different oscillating frequencies. In the proposed programmable method two different inductances connected in series to the quartz crystal are switched in a short time sequence, compensating the crystal’s natural temperature characteristics (in the temperature range between 0 and 50 °C. The procedure allows for the measurement of the converter hysteresis at various values of capacitance connected in parallel with the quartz crystal for the converter sensitivity setting at selected inductance. It, furthermore, enables the measurement of hysteresis at various values of inductance at selected parallel capacitance (sensitivity connected to the quartz crystal. The article shows that the proposed hysteresis measurement of the converter, which converts the inductance in the range between 95 and 100 μH to a frequency in the range between 1 and 200 kHz, has only 7 × 10−13 frequency instability (during the temperature change between 0 and 50 °C with a maximum 1 × 10−11 hysteresis frequency difference.

  12. Characterisation of blue-light stimulated luminescence components in different quartz samples: implications for dose measurement

    Energy Technology Data Exchange (ETDEWEB)

    Jain, M. E-mail: mayank.jain@risoe.dk; Murray, A.S.; Boetter-Jensen, L

    2003-10-01

    Over the last few years, we have become increasingly confident that quartz is a reliable natural dosimeter for sediment dating. Nevertheless, there is only a limited understanding of the behaviour of the different components of optically stimulated luminescence (OSL) from quartz. Recent single-aliquot dose-evaluation protocols seem to be relatively free of complications when applied to quartz dominated by the fast OSL component coming from 325 deg. C TL region, but this may not be true for quartz in which other components are more significant. An adequate understanding of how different OSL components behave during various measurement cycles is critical to ensuring that our dose evaluation protocols are robust and it is also important to our interpretation of the variation of apparent dose with optical stimulation time for identification of partial bleaching. We report here the principal results from measurement of (a) sensitisation, (b) thermal stability, (c) recuperation, and (d) infrared response as a function of stimulation temperature from 3 different samples of sedimentary quartz selected on the basis of relative OSL contribution from different blue light stimulated linearly modulated (LM-OSL) components. We then discuss the implications of these characteristics for dose assessment using the single aliquot regeneration dose protocol.

  13. High-Precision Hysteresis Sensing of the Quartz Crystal Inductance-to-Frequency Converter

    Science.gov (United States)

    Matko, Vojko; Milanović, Miro

    2016-01-01

    A new method for the automated measurement of the hysteresis of the temperature-compensated inductance-to-frequency converter with a single quartz crystal is proposed. The new idea behind this method is a converter with two programmable analog switches enabling the automated measurement of the converter hysteresis, as well as the temperature compensation of the quartz crystal and any other circuit element. Also used is the programmable timing control device that allows the selection of different oscillating frequencies. In the proposed programmable method two different inductances connected in series to the quartz crystal are switched in a short time sequence, compensating the crystal’s natural temperature characteristics (in the temperature range between 0 and 50 °C). The procedure allows for the measurement of the converter hysteresis at various values of capacitance connected in parallel with the quartz crystal for the converter sensitivity setting at selected inductance. It, furthermore, enables the measurement of hysteresis at various values of inductance at selected parallel capacitance (sensitivity) connected to the quartz crystal. The article shows that the proposed hysteresis measurement of the converter, which converts the inductance in the range between 95 and 100 μH to a frequency in the range between 1 and 200 kHz, has only 7 × 10−13 frequency instability (during the temperature change between 0 and 50 °C) with a maximum 1 × 10−11 hysteresis frequency difference. PMID:27367688

  14. Quartz luminescence response to a mixed alpha-beta field: Investigations on Romanian loess

    DEFF Research Database (Denmark)

    Constantin, Daniela; Jain, Mayank; Murray, Andrew S.

    2015-01-01

    Previous SAR-OSL dating studies using quartz extracted from Romanian and Serbian loess samples report SAR-OSL dose-response curves on fine grained (4-11μm) quartz that grow to much higher doses compared to those of coarse-grained (63-90, 90-125, 125-180μm) quartz. Furthermore, quartz SAR......-OSL laboratory dose response curves do not reflect the growth of the OSL signal in nature. A main difference in coarse- and fine-grained quartz dating lies in the alpha irradiation history, but the effect of mixed alpha-beta fields has so far received little attention. In the present study we investigate whether...... radiation follow the same recombination path. We also show that a mixed alpha-beta dose response reproduces the beta dose response only up to about 800Gy. Assuming an a-value of 0.04 we have shown that laboratory alpha and beta dose response curves overlap up to effective alpha doses of ~50Gy. Based...

  15. The CMS forward calorimeter with quartz fibres

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    Part of the forward hadron calorimeter for the CMS experiment at the LHC is seen here. The calorimeter will be placed at the ends of the experiment barrel to measure the energy of particles produced in the 14 TeV proton-proton collisions. In consists of an iron absorber and specially designed radiation-hard quartz so that it survives the high radiation levels produced by collisions.

  16. THE FRICTION OF QUARTZ IN HIGH VACUUM

    Science.gov (United States)

    the effects of surface cleanliness . Ultra-high vacuums (to 10 to the minus 10th power torr) and high temperatures (to 350 deg C) were combined with...chemical cleaning and careful handling techniques to produce the maximum surface cleanliness . The coefficient of static friction under varying...on 30-40 mesh glass balls. The coefficient of friction of smooth quartz was found to vary from 0.1 to 1.0 depending on the surface cleanliness . The

  17. Shock experiments on pre-heated alpha- and beta-quartz: 1. Optical and density data

    Science.gov (United States)

    Langenhorst, Falko; Deutsch, Alexander

    1994-07-01

    the following characteristics: (1) The frequency of set of (10-13) planes is high at 20 GPa, declines with increasing pressure, and finally is totally absent at 32 GPa, (2) set of (10-13) planes begins to occur at 25 GPa, increases, and finally is the only remaining orientation at 32 GPa, and (3) set of (10-12) planes and set of (11-22) planes are only present at 20 and 25 GPa. In contrast, quartz shocked at 630 C parallel to (10-10) displays a broad PDF distribution with indistinct maxima, and set of (10-13) planes is totally absent. The small structural difference between alpha- and beta-quartz which is reflected in the PDF distribution, should allow, in principle, evaluation of the pre-shock temperature in naturally impacted metamorphic rocks.

  18. High-temperature sapphire optical sensor fiber coatings

    Science.gov (United States)

    Desu, Seshu B.; Claus, Richard O.; Raheem, Ruby; Murphy, Kent A.

    1990-10-01

    the filter. These modes may be attributed to a number of material degradation mechanisms, such as thermal shock, oxidation corrosion of the material, mechanical loads, or phase changes in the filter material. Development of high temperature optical fiber (sapphire) sensors embedded in the CXF filters would be very valuable for both monitoring the integrity of the filter during its use and understanding the mechanisms of degradation such that durable filter development will be facilitated. Since the filter operating environment is very harsh, the high temperature sapphire optical fibers need to be protected and for some sensing techniques the fiber must also be coated with low refractive index film (cladding). The objective of the present study is to identify materials and develop process technologies for the application of claddings and protective coatings that are stable and compatible with sapphire fibers at both high temperatures and pressures.

  19. Stability and Phase Noise Tests of Two Cryo-Cooled Sapphire Oscillators

    Science.gov (United States)

    Dick, G. John; Wang, Rabi T.

    1998-01-01

    , and Q of 7.4 x 10 (exp 8). These values compare to a turn-over of 8.821 K and Q of 1.0 x 10 (exp 9) for the first resonator. Operation of this second unit provides a capability to directly verify for the first time the short-term (1 second less than or equal to tau less than or equal to 200 seconds) stability and the phase noise of the CSO units. The RF receiver used in earlier tests was sufficient to meet Cassini requirements for tau greater than or equal to 10 seconds but had short-term stability limited to 2-4 x 10 (exp -14) at tau = 1 second, a value 10 times too high to meet our requirements. A new low-noise receiver has been designed to provide approximately equal to 10-15 performance at 1 second, and one receiver is now operational, demonstrating again short-term CSO performance with H maser-limited stability. Short-term performance was degraded in the old receiver due to insufficient tuning bandwidth in a 100MHZ quartz VCO that was frequency-locked to the cryogenic sapphire resonator. The new receivers are designed for sufficient bandwidth, loop gain and low noise to achieve the required performance.

  20. Luminescence sensitivity changes in quartz as a result of annealing

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Agersnap Larsen, N.; Mejdahl, V.

    1995-01-01

    Retrospective dosimetry using optically stimulated luminescence (OSL) on quartz extracted from (for example) bricks needs to account for strong OSL sensitivity changes that are known to occur depending on the previous thermal treatment of the sample. Non-heated quartz exhibits OSL orders of magni......Retrospective dosimetry using optically stimulated luminescence (OSL) on quartz extracted from (for example) bricks needs to account for strong OSL sensitivity changes that are known to occur depending on the previous thermal treatment of the sample. Non-heated quartz exhibits OSL orders...... of magnitude less per unit radiation than that for heated material. The reason these temperature-induced sensitivity changes occur in quartz is presently not well understood. This phenomenon is also seen in the related area of luminescence dating in which sedimentary quartz and quartz from heated...

  1. Effects of citric acid on separation of sillimanite from quartz

    Institute of Scientific and Technical Information of China (English)

    李晔; 雷东升; 鲁巍; 许时

    2002-01-01

    Quartz is the main gangue mineral of sillimanite. The results show that Al3+ and Fe3+ ion can activate the floatation of quartz and make the separation of quartz and sillimanite difficult when anion collector is used, and citric acid can inhibit the quartz activated by metallic ion and have slight influence on the sillimanite. X-ray photoelectronic energy spectrum analysis indicates that there are obvious electronic energy peaks on the surface of the quartz before citric acid is added into the ore pulp in presence of Al3+ and Fe3+, and after citric acid is added, the energy peak vanished. So citric acid can make Al3+ and Fe3+ on the surface of quartz solve and decrease the active points on the surface of quartz which can adsorb anion collector.

  2. Room Temperature Experiments with a Macroscopic Sapphire Mechanical Oscillator

    Science.gov (United States)

    Bourhill, Jeremy; Ivanov, Eugene; Tobar, Micahel

    2015-03-01

    We present initial results from a number of experiments conducted on a 0.53 kg sapphire ``dumbbell'' crystal. Mechanical motion of the crystal structure alters the dimensions of the crystal, and the induced strain changes the permittivity. These two effects frequency modulate resonant microwave whispering gallery modes, simultaneously excited within the crystal. A novel microwave readout system is described allowing extremely low noise measurements of this frequency modulation with a phase noise floor of -160 dBc/Hz at 100 kHz, near our modes of interest. Fine-tuning of the crystal's suspension have allowed for the optimisation of mechanical Q-factors in preparation for cryogenic experiments, with a value of 8 x 107 achieved so far. Finally, results are presented that demonstrate the excitation of mechanical modes via radiation pressure force. These are all important steps towards the overall goal of the experiment; to cool a macroscopic device to the quantum ground state.

  3. Superexciplex of Coumarin Molecules using Tunable Ti-Sapphire Laser

    Science.gov (United States)

    Al-Ghamdi, Attieh Ali; Al-Dwayyan, Abdullah S.; Masilamani, Vadivel; Al-Saud, Turki Saud M.; Al-Salhi, Mohammed Saleh

    2003-10-01

    Certain highly polar dye molecules exhibit an additional optical gain band under pulsed laser excitation, while there is no such band under steady-state continuous wave (CW) lamp excitation. This new band is not due to an excimer, an exciplex or a two-photon fluorescence band but stems from the formation of a new molecular complex in which two excited molecules remain associated with a solvent molecule acting as a bridge. In this paper, the characteristics of superexciplexes of four related coumarin molecules are presented. All molecules were excited using a tunable Ti-sapphire laser pulse 10 ns in width. The distinct difference between the amplified spontaneous emission (ASE) spectra obtained with tunable laser and tunable lamp excitation demonstrated that twisted intramolecular charge transfer (TICT) conformations might also assist in the formation of these superexciplexes.

  4. The charge state of iron implanted into sapphire

    Energy Technology Data Exchange (ETDEWEB)

    McHargue, C.J.; Sklad, P.S.; White, C.W.; Farlow, G.C.; Perez, A.; Kornilios, N.; Marest, G.

    1987-08-01

    Several techniques (RBS, TEM, CEMS) have been used to characterize sapphire single crystals implanted with iron at room temperature to fluences of 10/sup 16/ to 10/sup 17/ ions cm/sup -2/. At low fluences the as-implanted iron is found mainly in the ferrous state. As the fluence is increased, Fe/sup 3 +/ and metallic iron clusters became dominant. There is a strong correlation between the probability of finding specific configurations of iron ions within four cation coordination shells and the relative amounts of each charge state observed. The superparamagnetic behavior of the clusters suggest that they are of the order of 2 nm in size but the large amount of irradiation-induced damage and residual stress has prevented their imaging by TEM. 13 refs., 7 figs.

  5. Numerical computation of sapphire crystal growth using heat exchanger method

    Science.gov (United States)

    Lu, Chung-Wei; Chen, Jyh-Chen

    2001-05-01

    The finite element software FIDAP is employed to study the temperature and velocity distribution and the interface shape during a large sapphire crystal growth process using a heat exchanger method (HEM). In the present study, the energy input to the crucible by the radiation and convection inside the furnace and the energy output through the heat exchanger is modeled by the convection boundary conditions. The effects of the various growth parameters are studied. It is found that the contact angle is obtuse before the solid-melt interface touches the sidewall of the crucible. Therefore, hot spots always appear in this process. The maximum convexity decreases significantly when the cooling-zone radius (RC) increases. The maximum convexity also decreases significantly as the combined convection coefficient inside the furnace (hI) decreases.

  6. Adapting a Cryogenic Sapphire Oscillator for Very Long Baseline Interferometry

    CERN Document Server

    Doeleman, Sheperd; Rogers, Alan; Hartnett, John; Tobar, Michael; Nand, Nitin; 10.1086/660156

    2011-01-01

    Extension of very long baseline interferometry (VLBI) to observing wavelengths shorter than 1.3mm provides exceptional angular resolution (~20 micro arcsec) and access to new spectral regimes for the study of astrophysical phenomena. To maintain phase coherence across a global VLBI array at these wavelengths requires that ultrastable frequency references be used for the heterodyne receivers at all participating telescopes. Hydrogen masers have traditionally been used as VLBI references, but atmospheric turbulence typically limits (sub) millimeter VLBI coherence times to ~1-30 s. Cryogenic Sapphire Oscillators (CSO) have better stability than Hydrogen masers on these time scale and are potential alternatives to masers as VLBI references. Here, We describe the design, implementation and tests of a system to produce a 10 MHz VLBI frequency standard from the microwave (11.2 GHz) output of a CSO. To improve long-term stability of the new reference, the CSO was locked to the timing signal from the Global Positionin...

  7. Fluid inclusions and microstructures in experimentally deformed quartz single crystals

    Science.gov (United States)

    Thust, A.; Tarantola, A.; Heilbronner, R.; Stünitz, H.

    2009-04-01

    The "H2O-weakening" effect that reduces the strength of quartz dramatically (e.g. Griggs & Blacic 1965) is still not understood. For example, Kronenberg & Tullis (1984) conclude that the weakening effect is pressure dependent while Paterson (1989) infers a glide and recovery control of water. Obviously, the spatial distribution and transport of H2O are important factors (Kronenberg et al. 1986, FitzGerald et al. 1991). We have carried out experiments on milky quartz in a Griggs deformation apparatus. Cylinders (6.5 mm in diameter, 12-13 mm in length) from a milky zone of a natural quartz single crystal have been cored in orientations (1) normal to one of the prism planes and (2) 45˚ to and 45˚ to (O+orientation). At 1 GPa confining pressure, 900˚ C and 10-6s-1, the flow strength is 150 MPa for samples with orientation (1). Further experiments are needed to establish the flow strength for orientation (2). FTIR measurements on double-polished thick sections (200-500 μm) in the undeformed quartz material yield an average H2O content of approximately 100 H/106Si. The water is heterogeneously distributed in the sample. Direct measurements on fluid inclusions yield a H2O content of more than 25 000 H/106Si. Thus, the H2O in the undeformed material is predominantly present in fluid inclusions of size from tens to hundred microns. Micro-thermometric measurements at low temperature indicate the presence of different salts in the fluid inclusions. The ice melting temperature, between -6.9 and -7.4˚ C, indicate an average salinity of 10.5 wt% NaCl. After deformation the distribution of H2O is more homogeneous throughout the sample. The majority of the big inclusions have disappeared and very small inclusions of several microns to sub-micron size have formed. FTIR measurements in zones of undulatory extinction and shear bands show an average H2O content of approximately 3000 H/106Si. Moreover, the larger fluid inclusions are characterized by a higher salinity (12 wt%) due

  8. Analysis and modification of blue sapphires from Rwanda by ion beam techniques

    Energy Technology Data Exchange (ETDEWEB)

    Bootkul, D., E-mail: mo_duangkhae@hotmail.com [Department of General Science - Gems & Jewelry, Faculty of Science, Srinakharinwirot University, Bangkok 10110 (Thailand); Chaiwai, C.; Tippawan, U. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wanthanachaisaeng, B. [Gems Enhancement Research Unit, Faculty of Gems, Burapha University, Chanthaburi Campus, Chanthaburi 22170 (Thailand); Intarasiri, S., E-mail: saweat@gmail.com [Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2015-12-15

    Highlights: • Ion beam analysis is an effective method for detecting trace elements. • Ion beam treatment is able to improve optical and color appearances of the blue sapphire from Rwanda. • These alternative methods can be extended to jewelry industry for large scale application. - Abstract: Blue sapphire is categorised in a corundum (Al{sub 2}O{sub 3}) group. The gems of this group are always amazed by their beauties and thus having high value. In this study, blue sapphires from Rwanda, recently came to Thai gemstone industry, are chosen for investigations. On one hand, we have applied Particle Induced X-ray Emission (PIXE), which is a highly sensitive and precise analytical technique that can be used to identify and quantify trace elements, for chemical analysis of the sapphires. Here we have found that the major element of blue sapphires from Rwanda is Al with trace elements such as Fe, Ti, Cr, Ga and Mg as are commonly found in normal blue sapphire. On the other hand, we have applied low and medium ion implantations for color improvement of the sapphire. It seems that a high amount of energy transferring during cascade collisions have altered the gems properties. We have clearly seen that the blue color of the sapphires have been intensified after nitrogen ion bombardment. In addition, the gems were also having more transparent and luster. The UV–Vis–NIR measurement detected the modification of their absorption properties, implying of the blue color increasing. Here the mechanism of these modifications is postulated and reported. In any point of view, the bombardment by using nitrogen ion beam is a promising technique for quality improvement of the blue sapphire from Rwanda.

  9. Large-scale inhomogeneity in sapphire test masses revealed by Rayleigh scattering imaging

    Science.gov (United States)

    Yan, Zewu; Ju, Li; Eon, François; Gras, Slawomir; Zhao, Chunnong; Jacob, John; Blair, David G.

    2004-03-01

    Rayleigh scattering in test masses can introduce noise and reduce the sensitivity of laser interferometric gravitational wave detectors. In this paper, we present laser Rayleigh scattering imaging as a technique to investigate sapphire test masses. The system provides three-dimensional Rayleigh scattering mapping of entire test masses and quantitative evaluation of the Rayleigh scattering coefficient. Rayleigh scattering mapping of two sapphire samples reveals point defects as well as inhomogeneous structures in the samples. We present results showing significant non-uniform scattering within two 4.5 kg sapphire test masses manufactured by the heat exchanger method.

  10. natural

    Directory of Open Access Journals (Sweden)

    Elías Gómez Macías

    2006-01-01

    Full Text Available Partiendo de óxido de magnesio comercial se preparó una suspensión acuosa, la cual se secó y calcinó para conferirle estabilidad térmica. El material, tanto fresco como usado, se caracterizó mediante DRX, área superficial BET y SEM-EPMA. El catalizador mostró una matriz de MgO tipo periclasa con CaO en la superficie. Las pruebas de actividad catalítica se efectuaron en lecho fijo empacado con partículas obtenidas mediante prensado, trituración y clasificación del material. El flujo de reactivos consistió en mezclas gas natural-aire por debajo del límite inferior de inflamabilidad. Para diferentes flujos y temperaturas de entrada de la mezcla reactiva, se midieron las concentraciones de CH4, CO2 y CO en los gases de combustión con un analizador de gases tipo infrarrojo no dispersivo (NDIR. Para alcanzar conversión total de metano se requirió aumentar la temperatura de entrada al lecho a medida que se incrementó el flujo de gases reaccionantes. Los resultados obtenidos permiten desarrollar un sistema de combustión catalítica de bajo costo con un material térmicamente estable, que promueva la alta eficiencia en la combustión de gas natural y elimine los problemas de estabilidad, seguridad y de impacto ambiental negativo inherentes a los procesos de combustión térmica convencional.

  11. Petrophysical evaluation methods: basal quartz formation, Manyberries Area , Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Davis, B.W.

    1980-01-01

    Hydrocarbons, both oil and gas, have been discovered in the basal quartz formation in the Manyberries area of SE Alberta. Estimation of producible fluids and hydrocarbons in place has been difficult due to the very shaly nature of the reservoir rock. Calculations of water saturation with no corrections for clay conductivity underestimates the hydrocarbons in place. The Waxman-Smits evaluation technique, which provides a method to account for clay conductivities, was used to estimate water saturation based on total porosity. Work of other authors provides a technique to correlate total and effective porosities. This was used to estimate effective porosity and subsequently water saturation based on the effective porosity. Error analysis was undertaken to estimate the uncertainty in the calculated water saturations.

  12. Bioreactivity of the crystalline silica polymorphs, quartz and cristobalite, and implications for occupational exposure limits (OELs).

    Science.gov (United States)

    Mossman, Brooke T; Glenn, Robert E

    2013-09-01

    Silica or silicon dioxides (SiO₂) are naturally occurring substances that comprise the vast majority of the earth's crust. Because of their prevalence and commercial applications, they have been widely studied for their potential to induce pulmonary fibrosis and other disorders. Historically, the focus in the workplace has been on the development of inflammation and fibrotic lung disease, the basis for promulgating workplace standards to protect workers. Crystalline silica (CS) polymorphs, predominantly quartz and cristobalite, are used in industry but are different in their mineralogy, chemistry, surface features, size dimensions and association with other elements naturally and during industrial applications. Epidemiologic, clinical and experimental studies in the literature historically have predominantly focused on quartz polymorphs. Thus, in this review, we summarize past scientific evaluations and recent peer-reviewed literature with an emphasis on cristobalite, in an attempt to determine whether quartz and cristobalite polymorphs differ in their health effects, toxicity and other properties that may dictate the need for various standards of protection in the workplace. In addition to current epidemiological and clinical reports, we review in vivo studies in rodents as well as cell culture studies that shed light on mechanisms intrinsic to the toxicity, altered cell responses and protective or defense mechanisms in response to these minerals. The medical and scientific literature indicates that the mechanisms of injury and potential causation of inflammation and fibrotic lung disease are similar for quartz and cristobalite. Our analysis of these data suggests similar occupational exposure limits (OELs) for these minerals in the workplace.

  13. Strength and petrofabric of SiO2 across the phase boundary of quartz-coesite

    Science.gov (United States)

    Zhang, J.; Wang, Y.; Liu, Q.

    2010-12-01

    With increasing pressure, quartz, one of the major minerals of continental crust, transforms into its high-pressure polymorphs coesite (3-9 GPa), corresponding to a minimum metamorphic depth of about 100 km. The discovery of coesite inclusions (Chopin, 1984; Smith, 1984) in continental collision terranes stimulated the existence of the realm of “ultrahigh-pressure (UHP) metamorphism”. Coesite is now well-documented in both UHP rocks and their country rock - gneiss. However, the rheology and petrofabric of coesite are not well constrained in natural rocks due to the prevalent breakdown of coesite to quartz during exhumation. Here we report petrofabrics of quartz and coesite from a natural coesite eclogite and from SiO2 specimens deformed in the stability of coesite in the laboratory. Our preliminary results suggest: 1) The strength contrast of major component minerals in eclogite are qtz slip similar to low pressure fabrics; 3) Coesite develops fabrics similar to those common in deformed clinopyroxenes with [001] being the slip directions and (100) or (010) being the slip planes. It is inferred that the transformation of quartz to coesite will increase seismic velocities but also strengthen seismic anisotropy in UHP rocks.

  14. AEROSOL FILTRATION USING QUARTZ SAND FILTER

    Directory of Open Access Journals (Sweden)

    Abbas H. Sulaymon

    2012-01-01

    Full Text Available The cement industry is the major source of cement dust which contains heavy metals like nickel, cobalt, lead, chromium, arsenic and hazardous substances like dioxins and furans. Exposure to these substances can cause health problems to human, animals and vegetation. A continuous pilot scale quartz sand filter was constructed and uses to study the effect of important design parameters (temperature, pre-loaded dust on the collector, diameter of the filter, bed depth, collector size and superficial velocity on its performance for cleaning of cement dust from air. Initial penetration and initial pressure drop (after 180s were measured and compared for different variables used in this study. The dirty bed was cleaned by means of reverse air flow when the pressure drop across the filter rises to 20 cmH2O. A macroscopic model describes the filter clogging was used to predict the effluent histories based on initial collection efficiency (η0exp which was determined from experimental data. A removal efficiency of more than 99% was obtained. The results show that 0.4% of cement dust still adheres on the quartz sand bed after 5 min of cleaning cycle. The presence of 0.4% of pre-load dust on the quartz sand filter enhanced the efficiency and low initial penetration, moderate initial pressure drop was obtained. At given Empty Bed Contact Time (EBCT, with different filter diameters 30 and 15 cm, a sharp decrease in initial penetration from 0.41-0.03 was obtained respectively. A nonlinear relationship between penetration and temperature was found. The initial penetration can be reduced by using smaller filter diameter, small collector size and collector with pre-load dust with 0.4%. The experiment that operates at a filter diameter of 15 cm and temperature of 25°C represent the minimum penetration among all the experiments.

  15. Quartz resonator instabilities under cryogenic conditions.

    Science.gov (United States)

    Goryachev, Maxim; Galliou, Serge; Abbe, Philippe; Bourgeois, Pierre-Yves; Grop, Serge; Dubois, Benoit

    2012-01-01

    The phase noise of a quartz crystal resonator working at liquid helium temperatures is studied. Measurement methods and the device environment are explained. The phase noise is measured for different resonance modes, excitation levels, amount of operating time, device orientations in relation to the cryocooler vibration axis, and temperatures. Stability limits of a frequency source based on such devices are evaluated in the present measurement conditions. The sources of phase flicker and white noises are identified. Finally, the results are compared with previous works.

  16. Robert Boyle's chiral crystal chemistry: computational re-evaluation of enantioselective adsorption on quartz.

    Science.gov (United States)

    Kahr, Bart; Chittenden, Brianne; Rohl, Andrew

    2006-02-01

    While searching for early examples of interactions of organic chromophores with minerals in the context of a systematic study of the process of dyeing crystals, we came across Robert Boyle's description of an experiment that may have been evidence of the enantioselective adsorption of a natural product, carminic acid (7-beta-D-glucopyranosyl-9,10-dihydro-3,5,6,8-tetrahydroxy-1-methyl-9,10-dioxo-2-anthracenecarboxylic acid), to the chiral surfaces of alpha-quartz, three centuries before such interactions became the subject of active chemical investigations. In order to determine whether Boyle did indeed observe enantioselective adsorption--albeit unbeknownst to him--we attempted to dye quartz with carminic acid according to his recipe. Quartz adsorbs carminic acid only because on heating it develops a network of microfissures that adsorb dye. This process depends on capillarity, not on specific non-covalent interactions; there is no evidence of enantioselectivity adsorption to heated crystals or enantioselective epitaxy to unheated crystals. These failures changed the focus of our inquiry: Why have almost all attempts to demonstrate the enantioselective adsorption of additives to quartz crystal surfaces been generally confounding and equivocal? In order to answer this question, we complement our experimental historical re-investigation with contemporary computational techniques for modeling crystal surface structure and the adsorption of additives. Minimizations of the energies associated with the adsorption of carminic acid to relaxed, hydrated d- and l-quartz {10(-)0} surfaces are analyzed in light of quartz's abysmal record as an enantioselective stationary phase.

  17. Frequency-doubled diode laser for direct pumping of Ti:sapphire lasers

    DEFF Research Database (Denmark)

    Müller, André; Jensen, Ole Bjarlin; Unterhuber, Angelika

    2012-01-01

    A single-pass frequency doubled high-power tapered diode laser emitting nearly 1.3 W of green light suitable for direct pumping of Ti:sapphire lasers generating ultrashort pulses is demonstrated. The pump efficiencies reached 75 % of the values achieved with a commercial solid-state pump laser....... However, the superior electro-optical efficiency of the diode laser improves the overall efficiency of the Ti:sapphire laser by a factor > 2. The optical spectrum emitted by the Ti:sapphire laser shows a spectral width of 112 nm (FWHM). Based on autocorrelation measurements, pulse widths of less than 20...... fs are measured. These results open the opportunity of establishing diode laser pumped Ti:sapphire lasers for e.g. biophotonic applications like retinal optical coherence tomography or pumping of photonic crystal fibers for CARS microscopy....

  18. MBE growth and characterization of ZnTe epilayers on m-plane sapphire substrates

    Energy Technology Data Exchange (ETDEWEB)

    Nakasu, Taizo; Sun, Wei-Che; Yamashita, Sotaro; Aiba, Takayuki; Taguri, Kosuke [Department of Electrical Engineering and Bioscience, Waseda University, Tokyo 169-8555 (Japan); Kobayashi, Masakazu [Department of Electrical Engineering and Bioscience, Waseda University, Tokyo 169-8555 (Japan); Kagami Memorial Research Institute for Materials Science and Technology, Waseda University, 2-8-26, Tokyo 169-0051 (Japan); Asahi, Toshiaki [Technology Development Center, JX Nippon Mining and Metals Corporation, Hitachi 317-0056 (Japan); Togo, Hiroyoshi [NTT Microsystem Integration Laboratories, Atsugi 243-0198 (Japan)

    2014-07-15

    ZnTe epilayers were grown on transparent (10-10) oriented (m -plane) sapphire substrates by molecular beam epitaxy (MBE). Pole figure imaging was used to study the domain distribution within the layer. (211)-oriented ZnTe domains were formed on m -plane sapphire. The presence of only one kind of (211) ZnTe domain formed on the 2 -tilted m -plane sapphire substrates was confirmed. Thus, single domain (211) ZnTe epilayers can be grown on the m -plane sapphire using MBE. Although differences in the crystal structure and lattice mismatch are large, precise control of the substrate surface lattice arrangement result in the formation of high-quality epitaxial layers. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Annealing effects of sapphire substrate on properties of ZnO films grown by magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.Z. [South China Normal University, School of Physics and Telecommunication Engineering, Guangzhou (China); Xu, J. [Chinese Academy of Sciences, Shanghai Institute of Optics and Fine Mechanics, P.O. Box 800-211, Shanghai (China)

    2007-09-15

    The annealing effects of sapphire substrates on the quality of epitaxial ZnO films grown by dc reactive magnetron sputtering were studied. The atomic steps formed on (0001) sapphire ({alpha}-Al{sub 2}O{sub 3}) substrates surface by annealing at high temperature were analyzed by atomic force microscopy. Their influence on the growth of ZnO films was examined by X-ray diffraction and photoluminescence measurements. Experimental results indicate that the film quality is strongly affected by annealing treatment of the sapphire substrate surface. The optimum annealing temperature of sapphire substrates for ZnO grown by magnetron sputtering is 1400 C for 1 h in air. (orig.)

  20. Dislocation Analysis for Large-sized Sapphire Single Crystal Grown by SAPMAC Method

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, large-sized sapphire (Φ230×210 mm, 27.5 kg) was grown by SAPMAC method (sapphire growth technique with micro-pulling and shoulder-expanding at the cooled center). Dislocation peculiarity in large sapphire boule (0001) basal plane was investigated by chemical etching, scanning electron microscopy and X-ray topography method. The triangular dislocation etch pit measured is 7.6×101~8.0×102 cm-2, in which relative high-density dislocations were generated at both initial and final stages of crystal growth. The analysis of single-crystal X-ray topography shows that there are no apparent sub-grain boundaries; the dislocation lines are isolated and straight. Finally, the origins of low-density dislocation in sapphire crystal are discussed by numerical analysis method.

  1. Advances in Trace Element "Fingerprinting" of Gem Corundum, Ruby and Sapphire, Mogok Area, Myanmar

    National Research Council Canada - National Science Library

    F Lin Sutherland; Khin Zaw; Sebastien Meffre; Tzen-Fui Yui; Kyaw Thu

    2015-01-01

    ... corundum area and also identified rare alluvial ruby and sapphire grains characterised by unusually high silicon, calcium and gallium, presence of noticeable boron, tin and niobium and very low iron, titanium and magnesium contents...

  2. Newly designed multilayer thin film mirror for dispersion compensation in Ti: sapphire femtosecond lasers

    Institute of Scientific and Technical Information of China (English)

    Chunyan Liao; Jianda Shao; Jianbing Huang; Zhengxiu Fan; Hongbo He

    2005-01-01

    @@ There are two different effects to generate group delay dispersion by multilayer thin film mirrors: chirper effect and Gires-Tournois effect. Both effects are employed to introduce desired dispersion in the designed mirror. Thus the designed mirror provides large dispersion throughout broad waveband. Such mirror can be used for dispersion compensation in Ti:sapphire femtosecond lasers. Most group delay dispersion of a 5-mm Ti:sapphire crystal can be compensated perfectly with only four bounces of the designed mirror.

  3. Growth of crystalline ZnO films on the nitridated (0001) sapphire surface

    Energy Technology Data Exchange (ETDEWEB)

    Butashin, A. V.; Kanevsky, V. M.; Muslimov, A. E., E-mail: amuslimov@mail.ru; Prosekov, P. A.; Kondratev, O. A.; Blagov, A. E.; Vasil’ev, A. L.; Rakova, E. V. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Babaev, V. A.; Ismailov, A. M. [Dagestan State University (Russian Federation); Vovk, E. A.; Nizhankovsky, S. V. [National Academy of Sciences of Ukraine, Institute for Single Crystals (Ukraine)

    2015-07-15

    The surface morphology and structure of (0001) sapphire substrates subjected to thermochemical nitridation in a mixture of N{sub 2}, CO, and H{sub 2} gases are investigated by electron and probe microscopy and X-ray and electron diffraction. It is shown that an aluminum nitride layer is formed on the substrate surface and heteroepitaxial ZnO films deposited onto such substrates by magnetron sputtering have a higher quality when compared with films grown on sapphire.

  4. Determining residual impurities in sapphire by means of electron paramagnetic resonance and nuclear activation analysis

    Science.gov (United States)

    Bletskan, D. I.; Bratus', V. Ya.; Luk'yanchuk, A. R.; Maslyuk, V. T.; Parlag, O. A.

    2008-07-01

    Sapphire (α-Al2O3) single crystals grown using the Verneuil and Kyropoulos methods have been analyzed using electron paramagnetic resonance and γ-ray spectroscopy with 12-MeV bremsstrahlung excitation. It is established that uncontrolled impurities in the final sapphire single crystals grown by the Kyropoulos method in molybdenum-tungsten crucibles are supplied both from the initial materials and from the furnace and crucible materials

  5. Jones calculus modeling and analysis of the thermal distortion in a Ti:sapphire laser amplifier.

    Science.gov (United States)

    Cho, Seryeyohan; Jeong, Jihoon; Yu, Tae Jun

    2016-06-27

    The mathematical modeling of an anisotropic Ti:sapphire crystal with a significant thermal load is performed. The model is expressed by the differential Jones matrix. A thermally induced distortion in the chirped-pulse amplification process is shown by the solution of the differential Jones matrix. Using this model, the thermally distorted spatio-temporal laser beam shape is calculated for a high-power and high-repetition-rate Ti:sapphire amplifier.

  6. High power all-solid-state quasi-continuous-wave tunable Ti: sapphire laser system

    Institute of Scientific and Technical Information of China (English)

    Lei Zou; Xin Ding; Yue Zou; Hongmei Ma; Wuqi Wen; Peng Wang; Jianquan Yao

    2005-01-01

    This paper reports a high power, all-solid-state, quasi-continuous-wave tunable Ti:sapphire laser system pumped by laser diode (LD) pumped frequency-doubled Nd:YAG laser. The maximum tuned output power of 4.2 W (797 nm) and tuned average power of 3.7 W were achieved when fixing the Ti:sapphire broadband output power at 5.0 W and applying 750-850 nm broadband coated mirror.

  7. Aleutian disease of mink: the antibody response of sapphire and pastel mink to Aleutian disease virus.

    Science.gov (United States)

    Bloom, M E; Race, R E; Hadlow, W J; Chesebro, B

    1975-10-01

    The specific antiviral antibody response of sapphire and pastel mink to Pullman strain of ADV has been examined. Sapphire mink inoculated with from 300,000-3 LD50 developed high levels of specific antibody and AD. Pastel mink inoculated with parallel doses of ADV also produced antibody but did not develop AD. The low incidence of AD in pastel mink inoculated with Pullman strain of ADV is probably related to factors other than antiviral antibody.

  8. Interface defects in GaN/sapphire studied using Rutherford backscattering spectroscopy and channeling

    Indian Academy of Sciences (India)

    S K Sinha; P K Barhai

    2004-06-01

    GaN on sapphire was grown by MOCVD technique. Rutherford backscattering spectra together with channeling along [0 0 0 1] axis were recorded to study the defects at the interface. Detailed calculation shows that the defects at GaN/sapphire interface are due to dislocations which are distributed into the whole thickness of the film and are mainly aligned on the growth direction.

  9. Aqueous Wetting Films on Fused Quartz.

    Science.gov (United States)

    Mazzoco; Wayner

    1999-06-15

    Using an image analyzing interferometer, IAI, the interfacial characteristics of an isothermal constrained vapor bubble, CVB, in a quartz cuvette were studied as a precursor to heat transfer research. The effects of pH and electrolyte concentration on the meniscus properties (curvature and adsorbed film thickness) and the stability of the aqueous wetting films were evaluated. The surface potential in the electric double layer was a function of the cleaning and hydroxylation of the quartz surface. The disjoining pressure isotherm for pure water was very close to that predicted by the Langmuir equation. For aqueous solutions of moderate electrolyte concentration, the Gouy-Chapman theory provided a good representation of the electrostatic effects in the film. The effect of temperature on the film properties of aqueous solutions and pure water was also evaluated: The meniscus curvature decreased with increasing temperature, while Marangoni effects, intermolecular forces, and local evaporation and condensation enhanced waves on the adsorbed film layer. Pure water wetting films were mechanically metastable, breaking into droplets and very thin films (less than 10 nm) after a few hours. Aqueous wetting films with pH 12.4 proved to be stable during a test of several months, even when subjected to temperature and mechanical perturbations. The mechanical stability of wetting films can explain the reported differences between the critical heat fluxes of pure water and aqueous solutions. The IAI-CVB technique is a simple and versatile experimental technique for studying the characteristics of interfacial systems. Copyright 1999 Academic Press.

  10. Production of quartz plates for CMS-CASTOR Experiment

    CERN Document Server

    Adiguzel, Aytul; Ayhan, Aydin; Bakirci, Mustafa Numan; Basegmez, Suzan; Beaumont, Willem; Borras, Kerstin; Campbell, Alan; De Paula Carvalho, W; Çerçi, Salim; De Jesus Damiao, Dilson; Dogangün, O; Dumanoglu, Isa; d'Enterria, David; Erchov, Y; Eskut, Eda; Figueiredo, D; Girgis, Semiray; Göttlicher, P; Gouskos, Loukas; Gurpinar, Emine; Hos, Ilknur; Katkov, Igor; Katsas, Panagiotis; Khein, Lev; Knutsson, Albert; Kuznetsov, Andrey; Lebeau, Michel; Van Mechelen, Pierre; Muhl, Carsten; Musienko, Yuri; Ochesanu, Silvia; Onengüt, G; Onengut, G Jr; Ozdemir, Kadri; Panagiotou, Apostolos; Polatoz, A; Ripert, Marion; Shileev, K; Sogut, Kenan; Tiflov, B TaliV; Kayis-Topaksu, A; Uzun, Dilber

    2008-01-01

    Light transmission rate performance of $102$ irradiated quartz samples was measured to select the best quartz plates for CMS-CASTOR calorimeter. All the produced quartz plates were originally used in a previous CERN experiment, DELPHI. Three different doses of $^{60}$Co source were used with the collaboration of PSI (Paul Scherrer Institute, Villigen PSI, Switzerland.) to study the transmission rate performance of the quartz samples after irradiation for different incident light, ranging from $250$ to $700$ nm in $5$ nm increasing steps. All samples show different decrease in the rate with wavelength for different doses. Three different steps were followed before irradiation to find out the best way of cleaning the original DELPHI Cu/Cr tracks on the samples. Results of these measurements presented here correspond to the quartz plates that will be used in one hadronic sector of CASTOR calorimeter until end of 2008. For the full calorimeter new quartz plates will be installed. We also present the light transmi...

  11. Supersmooth and modified surface of sapphire crystals: Formation, characterization, and applications in nanotechnologies

    Science.gov (United States)

    Muslimov, A. E.; Asadchikov, V. E.; Butashin, A. V.; Vlasov, V. P.; Deryabin, A. N.; Roshchin, B. S.; Sulyanov, S. N.; Kanevsky, V. M.

    2016-09-01

    The results of studying the state of the surface of sapphire crystals by a complex of methods in different stages of crystal treatment are considered by an example of preparing sapphire substrates with a supersmooth surface. The possibility of purposefully forming regular micro- and nanoreliefs and thin transition layers using thermal and thermochemical impacts are considered. The advantages of sapphire substrates with a modified surface for forming heteroepitaxial CdTe and ZnO semiconductor films and ordered ensembles of gold nanoparticles are described. The results of the experiments on the application of crystalline sapphire as a material for X-ray optical elements are reported. These elements include total external reflection mirrors and substrates for multilayer mirrors, output windows for synchrotron radiation, and monochromators working in the reflection geometry in X-ray spectrometers. In the latter case, the problems of the defect structure of bulk crystals sapphire and the choice of a method for growing sapphire crystals of the highest structural quality are considered.

  12. Structural and electronic characterization of graphene grown by chemical vapor deposition and transferred onto sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Joucken, Frédéric, E-mail: frederic.joucken@unamur.be; Colomer, Jean-François; Sporken, Robert; Reckinger, Nicolas

    2016-08-15

    Highlights: • CVD graphene is transferred onto sapphire. • Transport measurements reveal relatively low charge carriers mobility. • Scanning probe microscopy experiments reveal the presence of robust contaminant layers between the graphene and the sapphire, responsible for the low carriers mobility. - Abstract: We present a combination of magnetotransport and local probe measurements on graphene grown by chemical vapor deposition on copper foil and subsequently transferred onto a sapphire substrate. A rather strong p-doping is observed (∼9 × 10{sup 12} cm{sup −2}) together with quite low carrier mobility (∼1350 cm{sup 2}/V s). Atomic force and tunneling imaging performed on the transport devices reveals the presence of contaminants between sapphire and graphene, explaining the limited performance of our devices. The transferred graphene displays ridges similar to those observed whilst graphene is still on the copper foil. We show that, on sapphire, these ridges are made of different thicknesses of the contamination layer and that, contrary to what was reported for hBN or certain transition metal dichalcogenides, no self-cleansing process of the sapphire substrate is observed.

  13. Cellular and humoral antibody responses of normal pastel and sapphire mink to goat erythrocytes.

    Science.gov (United States)

    Lodmell, D L; Bergman, R K; Hadlow, W J; Munoz, J J

    1971-02-01

    This study was undertaken to determine whether normal sapphire and royal pastel mink differ immunologically at the cellular and humoral levels. Two days after primary intraperitoneal (ip) inoculation of goat erythrocytes (GE), essentially no 19 or 7S plaque-forming cells (PFC) per 10(6) cells were detected in spleen or in abdominal and peripheral lymph nodes of either color phase. On the 4th day, more 19S PFC were detected in pastel than in sapphire tissues; pastel tissues also contained 7S PFC, whereas essentially none was present in sapphires until the 6th day. After an ip booster inoculation, the number of PFC was markedly different between the two color phases. These differences were most apparent in spleen and peripheral lymph nodes. In parallel with differences observed in PFC responses between the color phases, total hemolysin and 2-mercaptoethanol-resistant hemolysin titers of pastels exceeded those of sapphires in all but one interval after the primary, and at every interval after the booster, inoculation. These data indicate that sapphire mink are not immunological cripples, nor are they immunologically hyperactive, but that differences do exist between sapphire and royal pastel mink, especially in the response to booster injections of GE.

  14. Modeling by regression for laser cutting of quartz crystal

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Presents the theoretical models built by analysis of the mechanism of laser cutting of quartz crystal and re gression of test results for the laser cutting of quartz crystal, and comparative analysis of calculation errors for these models, and concludes with test results that these models comprehensively reflect the physical features of laser cutting of quartz crystal and satisfy the industrial production requirements, and they can be used to select right parameters for improvement of productivity and quality and saving of energy.

  15. Mineral resource of the month: cultured quartz crystal

    Science.gov (United States)

    ,

    2008-01-01

    The article presents information on cultured quartz crystals, a mineral used in mobile phones, computers, clocks and other devices controlled by digital circuits. Cultured quartz, which is synthetically produced in large pressurized vessels known as autoclaves, is useful in electronic circuits for precise filtration, frequency control and timing for consumer and military use. Several ingredients are used in producing cultured quartz, including seed crystals, lascas, a solution of sodium hydroxide or sodium carbonate, lithium salts and deionized water.

  16. Laser surface and subsurface modification of sapphire using femtosecond pulses

    Energy Technology Data Exchange (ETDEWEB)

    Eberle, G., E-mail: eberle@iwf.mavt.ethz.ch [Institute of Machine Tools and Manufacturing, ETH Zurich, Leonhardstrasse 21, 8092 Zurich (Switzerland); Schmidt, M. [Chair of Photonic Technologies, University of Erlangen-Nuremberg, Konrad-Zuse-Strasse 3-5, 91052 Erlangen (Germany); Pude, F. [Inspire AG, Technoparkstrasse 1, 8005 Zurich (Switzerland); Wegener, K. [Institute of Machine Tools and Manufacturing, ETH Zurich, Leonhardstrasse 21, 8092 Zurich (Switzerland); Inspire AG, Technoparkstrasse 1, 8005 Zurich (Switzerland)

    2016-08-15

    Highlights: • Single and multipulse ablation threshold of aluminium oxide is determined. • Laser ablation, and in-volume modification followed by wet etching are demonstrated. • Quality following laser processing and laser-material interactions are studied. - Abstract: Two methods to process sapphire using femtosecond laser pulses are demonstrated, namely ablation (surface), and in-volume laser modification followed by wet etching (subsurface). Firstly, the single and multipulse ablation threshold is determined and compared with previous literature results. A unique application of ablation is demonstrated by modifying the entrance aperture of water jet orifices. Laser ablation exhibits advantages in terms of geometric flexibility and resolution, however, defects in the form of edge outbreaks and poor surface quality are evident. Secondly, the role of material transformation, polarisation state and formation of multi-focus structures after in-volume laser modification is investigated in order to explain their influence during the wet etching process. Laser scanning and electron microscopy as well as electron backscatter diffraction measurements supported by ion beam polishing are used to better understand quality and laser-material interactions of the two demonstrated methods of processing.

  17. Local dielectric permittivity profiles of sapphire/polypropylene interfaces

    Science.gov (United States)

    Yu, Liping; Ranjan, V.; Buongiorno Nardelli, M.; Bernholc, J.

    2009-03-01

    Recently, the need for high-power-density capacitors has stimulated research to develop composite dielectric materials with high-k nanoparticles embedded in a polymer matrix. In these materials, surfaces and interfaces may play an important role in determining the overall dielectric properties. We present first-principles investigations of the dielectric permittivity profiles across slabs and interfaces of sapphire(α-Al2O3)/isotactic-polypropylene(iPP). Our results indicate that the permittivity profile at interface strongly depends on the nanoscale averaging procedure. We propose an averaging model that ensures near-locality of the dielectric function. We find that: (i) the dielectric permittivity approaches the corresponding bulk value just a few atomic layers away from the interface or surface; (ii) the dielectric constant is enhanced at the surfaces of the isolated α-Al2O3 slabs, while no enhancement is observed at the iPP slab surfaces; and (iii) the dielectric transition at the αAl2O3/iPP is mainly confined in the αAl2O3 side.

  18. Q-Switching the Flash Ti: Sapphire Laser

    Energy Technology Data Exchange (ETDEWEB)

    Cone, Kelly

    2003-09-05

    The Stanford Linear Accelerator Center (SLAC) uses a flash lamp pumped Ti:Sapphire laser to generate the electron beam inside of the Linac. This laser system was installed at the SLAC Polarized Light Source in 1993. During the past, the system has been upgraded in several steps (eg. installation of Rhodium coated reflectors, cavity redesign, and remote controlled wavelength tunability). Q-switching the laser cavity to increase the peak pulse energy was successfully investigated and further improves the capabilities of the laser system for future polarized beam experiments. Two Pockels cells were used to perform the Q-switch and various diagnostics were used to characterize the modified laser pulse. The timing in relation to the laser trigger, pulse width, and pulse shape applied to the Q-switching Pockels cells (PC) were optimized. No damage to the laser cavity or optical elements occurred. At optimal conditions of Q-switching, the pulse energy of the laser increased from 0.4 mJ to over 3 mJ in a 300 ns pulse. The Q-switched pulse energy can be further increased by extending the hold-off pulse applied to the PC. The laser pulse produced by the Q-switch was long enough (full width half maximum (FWHM) > 200 ns) for pulse shaping and demonstrated good intensity stability (< 0.5% jitter). The increase in output power suggests that Q-switching will be used for future accelerator projects.

  19. Evaluation of the flexural strength of carbon, quartz, and glass fiber-based posts

    Directory of Open Access Journals (Sweden)

    Sita Rama Raju

    2014-01-01

    Full Text Available Objectives: This study was done to evaluate the flexural strength of carbon, quartz, and glass fiber posts by means of three-point bending test. Materials and Methods: Thirty pre-fabricated fiber posts were used and divided into three groups. Group I carbon fiber posts (C-Post, group II quartz fiber post (Aestheti Plus, group III glass fiber post (Para Post White Ten posts (N = 10 were used for each experimental group and were measured with digital caliper before test accomplishment. The fracture load of post specimens was measured, and flexural strength was obtained by the formula using S = 8FL/pd 3 . The values in Kgf/mm 2 were obtained and calculated to Mpa and submitted to ANOVA (a = 0.01 and to the Tukey′s test. Results: The mean values of flexural strength show that group II quartz fiber posts (666 MPa are significantly higher than group I carbon fiber (614 MPa and group III glass fiber (575 MPa. C onclusion: Hence, this study concluded that quartz fiber post showed significantly higher flexural strength values. Further scope of this study lies in the evaluation and evolution of a restorative materials used for post and core preparation, which have modulus of elasticity in harmony with that of dentin and near-natural esthetic appearance.

  20. An Exploration of the Metal Dependent Selectivity of a Metalloporphyrins Coated Quartz Microbalances Array

    Directory of Open Access Journals (Sweden)

    Alexandro Catini

    2016-10-01

    Full Text Available Several studies in the last two decades have demonstrated that metalloporphyrins coated quartz microbalances can be fruitfully used in many diverse applications, spanning from medical diagnosis to environmental control. This large versatility is due to the combination of the flexibility of metalloporphyrins molecular design with the independence of the quartz microbalance signal from the interaction mechanisms. The nature of the metal atom in the metalloporphyrins is often indicated as one of the most effective tools to design differently selective sensors. However, the properties of sensors are also strongly affected by the characteristics of the transducer. In this paper, the role of the metal atom is investigated studying the response, to various volatile compounds, of six quartz microbalance sensors that are based on the same porphyrin but with different metals. Results show that, since quartz microbalances (QMB transducers can sense all the interactions between porphyrin and volatile compounds, the metal ion does not completely determine the sensor behaviour. Rather, the sensors based on the same molecular ring but with different metal ions show a non-negligible common behaviour. However, even if limited, the different metals still confer peculiar properties to the sensors and might drive the sensor array identification of the pool of tested volatile compounds.

  1. An Exploration of the Metal Dependent Selectivity of a Metalloporphyrins Coated Quartz Microbalances Array

    Science.gov (United States)

    Catini, Alexandro; Kumar, Raj; Capuano, Rosamaria; Martinelli, Eugenio; Paolesse, Roberto; di Natale, Corrado

    2016-01-01

    Several studies in the last two decades have demonstrated that metalloporphyrins coated quartz microbalances can be fruitfully used in many diverse applications, spanning from medical diagnosis to environmental control. This large versatility is due to the combination of the flexibility of metalloporphyrins molecular design with the independence of the quartz microbalance signal from the interaction mechanisms. The nature of the metal atom in the metalloporphyrins is often indicated as one of the most effective tools to design differently selective sensors. However, the properties of sensors are also strongly affected by the characteristics of the transducer. In this paper, the role of the metal atom is investigated studying the response, to various volatile compounds, of six quartz microbalance sensors that are based on the same porphyrin but with different metals. Results show that, since quartz microbalances (QMB) transducers can sense all the interactions between porphyrin and volatile compounds, the metal ion does not completely determine the sensor behaviour. Rather, the sensors based on the same molecular ring but with different metal ions show a non negligible common behaviour. However, even if limited, the different metals still confer peculiar properties to the sensors and might drive the sensor array identification of the pool of tested volatile compounds. PMID:27782032

  2. Origin of Difference in Photocatalytic Activity of ZnO (002 Grown on a- and c-Face Sapphire

    Directory of Open Access Journals (Sweden)

    Guoqiang Li

    2014-01-01

    Full Text Available The oriented (002 ZnO films were grown on a- and c-face sapphire by pulsed laser deposition. The X-ray diffraction analysis revealed that the oriented (002 ZnO films were epitaxially grown on the substrate successfully. The sample on a-face sapphire had higher crystal quality. However, the photocatalytic activity for Rhodamine B degradation of ZnO film on c-face sapphire was higher than that on a-face sapphire. The Raman spectrum and XPS analysis suggested that the sample on a-face sapphire had higher concentration of defects. The result of the contact angle measurement revealed that the sample on c-face sapphire had higher surface energy. And the investigation of the surface conductance implied that the higher light conductance was helpful for the photocatalytic activity.

  3. Effects of sapphire substrates surface treatment on the ZnO thin films grown by magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yinzhen [School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510631 (China)], E-mail: agwyz@yahoo.com.cn; Chu Benli [School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510631 (China)

    2008-06-01

    The surface treatment effects of sapphire substrate on the ZnO thin films grown by magnetron sputtering were studied. The sapphire substrates properties have been investigated by means of atomic force microscopy (AFM) and X-ray diffraction rocking curves (XRCs). The results show that sapphire substrate surfaces have the best quality by CMP with subsequent chemical etching. The surface treatment effects of sapphire substrate on the ZnO thin films were examined by X-ray diffraction (XRD) and photoluminescence (PL) measurements. Results show that the intensity of (0 0 2) diffraction peak of ZnO thin films on sapphire substrates treated by CMP with subsequent chemical etching was strongest, FWHM of (0 0 2) diffraction peak is the narrowest and the intensity of UV peak of PL spectrum is strongest, indicating surface treatment on sapphire substrate preparation may improve ZnO thin films crystal quality and photoluminescent property.

  4. NMR spectroscopy of experimentally shocked single crystal quartz: A reexamination of the NMR shock barometer

    Science.gov (United States)

    Fiske, P. S.; Gratz, A. J.; Nellis, W. J.

    1993-01-01

    Cygan and others report a broadening of the Si-29 nuclear magnetic resonance (NMR) peak for synthetic quartz powders with increasing shock pressure which they propose as a shock wave barometer for natural systems. These results are expanded by studying single crystal quartz shocked to 12 and 33 GPa using the 6.5 m two-stage light-gas gun at Lawrence Livermore National Laboratories. Our NMR results differ substantially from those of Cygan and others and suggest that the proposed shock wave barometer may require refinement. The difference in results between this study and that of Cygan and others is most likely caused by different starting materials (single crystal vs. powder) and different shock loading histories. NMR results from single crystal studies may be more applicable to natural systems.

  5. NMR spectroscopy of experimentally shocked single crystal quartz: A reexamination of the NMR shock barometer

    Science.gov (United States)

    Fiske, P. S.; Gratz, A. J.; Nellis, W. J.

    1993-01-01

    Cygan and others report a broadening of the Si-29 nuclear magnetic resonance (NMR) peak for synthetic quartz powders with increasing shock pressure which they propose as a shock wave barometer for natural systems. These results are expanded by studying single crystal quartz shocked to 12 and 33 GPa using the 6.5 m two-stage light-gas gun at Lawrence Livermore National Laboratories. Our NMR results differ substantially from those of Cygan and others and suggest that the proposed shock wave barometer may require refinement. The difference in results between this study and that of Cygan and others is most likely caused by different starting materials (single crystal vs. powder) and different shock loading histories. NMR results from single crystal studies may be more applicable to natural systems.

  6. Diagenetic Quartz Morphologies and Zeolite formation

    DEFF Research Database (Denmark)

    Kazerouni, Afsoon Moatari; Hansen, Rikke Weibel; Friis, Henrik

    ; the core of the zeolite crystals appears to have been more unstable than the rim and dissolved first.  Later the entire crystal dissolved and left an impression of the euhedral zeolite crystal in the microquartz coating.  Such openings in the microquartz coating are nucleation points for macroquartz.  Thus......, the precipitation of zeolite may later facilitate further quartz cementation, which might otherwise be retarded by the presence of disordered microquartz. The silica activity of pore fluids can influence zeolite precipitation.  Although zeolite formation is clearly related to volcanic ash, zeolite has also formed...... are abundant in some of associated shales; and 2) volcanic ash. The dissolution of biogenic silica may result in a rapid release of silica thereby promoting the formation of diagenetic opal/microquartz, but there may be a limited release of Al. A limited release of Al may result in precipitation of Si...

  7. Quartz tuning fork based microwave impedance microscopy

    Science.gov (United States)

    Cui, Yong-Tao; Ma, Eric Yue; Shen, Zhi-Xun

    2016-06-01

    Microwave impedance microscopy (MIM), a near-field microwave scanning probe technique, has become a powerful tool to characterize local electrical responses in solid state samples. We present the design of a new type of MIM sensor based on quartz tuning fork and electrochemically etched thin metal wires. Due to a higher aspect ratio tip and integration with tuning fork, such design achieves comparable MIM performance and enables easy self-sensing topography feedback in situations where the conventional optical feedback mechanism is not available, thus is complementary to microfabricated shielded stripline-type probes. The new design also enables stable differential mode MIM detection and multiple-frequency MIM measurements with a single sensor.

  8. Shock Induced Emission from Sapphire in High-Pressure Phase of Rh2O3 (Ⅱ) Structure

    Institute of Scientific and Technical Information of China (English)

    ZHANG Dai-Yu; LIU Fu-Sheng; HAO Gao-Yu; SUN Yu-Huai

    2007-01-01

    @@ A distinct optical emission from the Rh2 O3 (Ⅱ) structural sapphire is observed under shock compression of 125,132, and 143 Gpa. The emission intensity continuously increases with the thickness of shocked sapphire. The colour temperature is determined to be about 4000K, which is obviously smaller than the reported value of the alpha phase alumina at the pressures below 80 Gpa. The present results suggest that the structural transformation will cause an obvious change of optical property in sapphire.

  9. Quartz enhanced photoacoustic spectroscopy based trace gas sensors using different quartz tuning forks.

    Science.gov (United States)

    Ma, Yufei; Yu, Guang; Zhang, Jingbo; Yu, Xin; Sun, Rui; Tittel, Frank K

    2015-03-27

    A sensitive trace gas sensor platform based on quartz-enhanced photoacoustic spectroscopy (QEPAS) is reported. A 1.395 μm continuous wave (CW), distributed feedback pigtailed diode laser was used as the excitation source and H2O was selected as the target analyte. Two kinds of quartz tuning forks (QTFs) with a resonant frequency (f0) of 30.72 kHz and 38 kHz were employed for the first time as an acoustic wave transducer, respectively for QEPAS instead of a standard QTF with a f0 of 32.768 kHz. The QEPAS sensor performance using the three different QTFs was experimentally investigated and theoretically analyzed. A minimum detection limit of 5.9 ppmv and 4.3 ppmv was achieved for f0 of 32.768 kHz and 30.72 kHz, respectively.

  10. A new irradiated quartz for beta source calibration

    DEFF Research Database (Denmark)

    Hansen, Vicki; Murray, Andrew Sean; Buylaert, Jan-Pieter;

    2015-01-01

    laboratories have used the various different batches of Risø calibration quartz for the calibration of beta and X-ray sources, but these have been largely undescribed. Here we describe in detail the preparation and luminescence characteristics of a new quartz standard, based on a North Sea beach sand collected...

  11. Quartz exposure in agriculture: literature review and South African survey.

    NARCIS (Netherlands)

    Swanepoel, A.J.; Rees, D.; Renton, K.; Swanepoel, C.; Kromhout, H.; Gardiner, K.

    2010-01-01

    OBJECTIVES: To review the published literature on respirable quartz exposure and associated disease in agricultural related settings systematically and to describe personal respirable dust and quartz measurements collected on a sandy soil farm in the Free State province of South Africa. METHODS: The

  12. Recent developments of OSL techniques for dating quartz and feldspars

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Jungner, H.; Mejdahl, V.

    1993-01-01

    The construction of a unit for measuring optically stimulated luminescence from quartz and feldspar is described. The light sources used for stimulation are infrared diodes for feldspar and green light from a halogen lamp (obtained with a system of filters) for both quartz and feldspar. The unit ...

  13. Speciation and phase separation of water in quartz (A review ...

    African Journals Online (AJOL)

    Speciation and phase separation of water in quartz (A review) ... of quartz at temperatures in excess of 500 °C. leading to decomposition of the ... The nucleation is a first order phase transition of creating liquid nucleus within the vapour phase, ...

  14. Removal of Ozone by Carbon Nanotubes/Quartz Fiber Film.

    Science.gov (United States)

    Yang, Shen; Nie, Jingqi; Wei, Fei; Yang, Xudong

    2016-09-01

    Ozone is recognized as a harmful gaseous pollutant, which can lead to severe human health problems. In this study, carbon nanotubes (CNTs) were tested as a new approach for ozone removal. The CNTs/quartz fiber film was fabricated through growth of CNTs upon pure quartz fiber using chemical vapor deposition method. Ozone conversion efficiency of the CNTs/quartz fiber film was tested for 10 h and compared with that of quartz film, activated carbon (AC), and a potassium iodide (KI) solution under the same conditions. The pressure resistance of these materials under different airflow rates was also measured. The results showed that the CNTs/quartz fiber film had better ozone conversion efficiency but also higher pressure resistance than AC and the KI solution of the same weight. The ozone removal performance of the CNTs/quartz fiber film was comparable with AC at 20 times more weight. The CNTs played a dominant role in ozone removal by the CNTs/quartz fiber film. Its high ozone conversion efficiency, lightweight and free-standing properties make the CNTs/quartz fiber film applicable to ozone removal. Further investigation should be focused on reducing pressure resistance and studying the CNT mechanism for removing ozone.

  15. Analysis of Rare Earth Elements (REE) in vein quartz and quartz-sandstone host rock in the Zhelannoe high purity quartz deposit, Russia

    Science.gov (United States)

    Zemskova, Marina; Prokofiev, Vsevolod; Bychkov, Andrey

    2015-04-01

    The Zhelannoe high purity quartz deposit is located on the western slope of the Polar Urals. It is one of the largest deposits of vein quartz and rock crystal in Russia. Most of the mineralization is hosted within a single horizon of very firm quartz-sandstone, where plastic deformation did not occur almost entirely. All tectonic stress was released by the development of numerous thrust faults of different scales. Cavities formed during this process were later filled with quartz and rock crystal. In order to obtain more details on conditions under which mineralization took place, analysis of trace element contents in vein quartz and host rocks, and the micro-thermometric study of fluid inclusions in quartz have been carried out. The trace element composition of vein quartz and of the host rock has been determined by ICP-MS. The results have shown that concentrations of most of the 46 studied elements in quartz are two orders of magnitude lower than in chondrite, and more than three orders of magnitude lower than in the upper crust. Even though Pb and Li have the highest concentrations in quartz samples, levels are only nearly comparable in chondrite, and substantially lower in the upper crust. At the same time, negative anomalies of Pb and Li concentrations in the host rock may indicate the removal of these elements during vein quartz formation. Contents of most REEs are two orders of magnitude lower than in chondrite, and three orders of magnitude lower than in the host rock. Generally, the patterns of REE distribution in vein quartz and the host rock express a clear correlation; confirming the genetic link between vein quartz and quartz-sandstone host rock. However, the process of quartz recrystallization led to an intense decrease of REEs content, and of all other impurities, which consequently influenced industrial value of the Zhelannoe deposit. As a result of the micro-thermometric study of fluid inclusions in quartz, the following physical

  16. Comparison of thermoluminescence (TL) and cathodoluminescence (ESEM-CL) properties between hydrothermal and metamorphic quartzes

    Energy Technology Data Exchange (ETDEWEB)

    Topaksu, M., E-mail: mtopaksu@adiyaman.edu.tr [Department of Physics, Faculty of Science and Art, Adiyaman University, 02040 Adiyaman (Turkey); Correcher, V. [CIEMAT, Av. Complutense 22, Madrid 28040 (Spain); Garcia-Guinea, J. [CSIC, Museo Nacional de Ciencias Naturales, C/Jose Gutierrez Abascal 2, Madrid 28006 (Spain); Topak, Y. [Adiyaman University, Vocational High School, 02040 Adiyaman (Turkey); Goeksu, H.Y. [Department of Physics, Faculty of Science and Art, Adiyaman University, 02040 Adiyaman (Turkey)

    2012-06-15

    This paper reports on the Thermoluminescence (TL) and Cathodoluminescence (CL) emission of well-characterized hydrothermal milky quartz specimens from Hakkari in Turkey, labeled THQ, and Madrid in Spain, labeled SHQ, and metamorphic quartz from Madrid, in Spain, labeled SMQ. Both hydrothermal and metamorphic quartz samples display similar UV-IR CL spectra consisting of five groups of components centered at 330 nm and 380 nm linked to [AlO{sub 4}] Degree-Sign centers, 420 nm due to intrinsic defects such as oxygen vacancies, lattice defects, and impurities which modify the crystal structure, 480 nm associated with [AlO{sub 4}] Degree-Sign centers of substitutional Al{sup 3+}, and a red broad band related to the hydroxyl defects in the quartz lattice as precursors of non-bridging oxygen hole centers (NBOHC) and substitutional point defects. The Turkish quartz specimen exhibits higher CL intensity in the UV region (up to 330 nm) than the Spanish specimens probably linked to the presence of Ca (0.95% in THQ and less than 0.1% in SHQ and SMQ). At wavelengths greater than 330 nm, SMQ (formed at high pressure 6000 bars and temperatures over 500-600 Degree-Sign C) shows higher intensity than the hydrothermal (growth at 2000 bars and temperatures 200-300 Degree-Sign C) samples associated with the formation process. The natural blue TL glow curves of both THQ and SHQ display a weaker TL intensity than the SMQ, attributable to the Al (0.32%), Ti (0.14%), K (0.01%) and Zr (76 ppm) content. It is shown that mineralogical formation, crystallinity index and the content of the impurities seem to be the main parameters of influence in the shape intensity of the CL and TL glow curve emission. - Highlights: Black-Right-Pointing-Pointer We reported on the TL and CL emission of well-characterized hydrothermal milky and metamorphic quartz specimens. Black-Right-Pointing-Pointer Hydrothermal and metamorphic quartz samples displayed similar UV-IR CL spectra. Black

  17. Nanoscratch Characterization of GaN Epilayers on c- and a-Axis Sapphire Substrates

    Directory of Open Access Journals (Sweden)

    Wen Hua-Chiang

    2010-01-01

    Full Text Available Abstract In this study, we used metal organic chemical vapor deposition to form gallium nitride (GaN epilayers on c- and a-axis sapphire substrates and then used the nanoscratch technique and atomic force microscopy (AFM to determine the nanotribological behavior and deformation characteristics of the GaN epilayers, respectively. The AFM morphological studies revealed that pile-up phenomena occurred on both sides of the scratches formed on the GaN epilayers. It is suggested that cracking dominates in the case of GaN epilayers while ploughing during the process of scratching; the appearances of the scratched surfaces were significantly different for the GaN epilayers on the c- and a-axis sapphire substrates. In addition, compared to the c-axis substrate, we obtained higher values of the coefficient of friction (μ and deeper penetration of the scratches on the GaN a-axis sapphire sample when we set the ramped force at 4,000 μN. This discrepancy suggests that GaN epilayers grown on c-axis sapphire have higher shear resistances than those formed on a-axis sapphire. The occurrence of pile-up events indicates that the generation and motion of individual dislocation, which we measured under the sites of critical brittle transitions of the scratch track, resulted in ductile and/or brittle properties as a result of the deformed and strain-hardened lattice structure.

  18. Growth and Crystal Orientation of ZnTe on m-Plane Sapphire with Nanofaceted Structure

    Science.gov (United States)

    Nakasu, Taizo; Sun, Wei-Che; Kobayashi, Masakazu; Asahi, Toshiaki

    2016-11-01

    ZnTe thin films on sapphire substrate with nanofaceted structure have been studied. The nanofaceted structure of the m-plane (10-10) sapphire was obtained by heating the substrate at above 1100°C in air, and the r-plane (10-12) and S-plane (1-101) were confirmed. ZnTe layers were prepared on the nanofaceted m-plane sapphire substrates by molecular beam epitaxy (MBE). The effect of the nanofaceted structure on the orientation of the thin films was examined based on x-ray diffraction (XRD) pole figures. Transmission electron microscopy (TEM) was also employed to characterize the interface structures. The ZnTe layer on the nanofaceted m-plane sapphire substrate exhibited (331)-plane orientation, compared with (211)-plane without the nanofaceted structure. After thermal treatment, the m-plane surface vanished and (211) layer could not be formed because of the lack of surface lattice matching. On the other hand, (331)-plane thin film was formed on the nanofaceted m-plane sapphire substrate, since the (111) ZnTe domains were oriented on the S-facet. The orientation of the ZnTe epilayer depended on the atomic ordering on the surface and the influence of the S-plane.

  19. Carbon nanotube assisted Lift off of GaN layers on sapphire

    Science.gov (United States)

    Long, Hao; Feng, Xiaohui; Wei, Yang; Yu, Tongjun; Fan, Shoushan; Ying, Leiying; Zhang, Baoping

    2017-02-01

    Laser lift off (LLO) was one of the most essential processes in fabrication of vertical GaN-based LEDs. However, traditional laser lift off of GaN on sapphire substrates needed high laser energy threshold, which deteriorated the GaN crystal. In this paper, it was found that inserting carbon nanotube between GaN and sapphire could effectively reduce the laser energy threshold in GaN LLO, from 1.5 J /cm2 of conventional GaN/sapphire to 1.3 J /cm2 of CNT inserted GaN/sapphire. The temperature distributions at the GaN/sapphire interfaces with and without CNTs were simulated by the finite elements calculation under laser irradiation. It was found that, due to the higher laser absorption coefficient of CNT, the CNT played as a powerful heating wire, sending out the thermal outside to elevate the GaN's temperature, and thus reduce the laser threshold for LLO. Raman and photoluminescence measurements indicated that residual stress of GaN membranes was as small as 0.3 GPa by the carbon nanotube assisted LLO. This work not only opens new application of CNTs, but also demonstrates the potential of high performance blue and green LEDs.

  20. Variable Energy Positron Annihilation Spectroscopy of GaN Grown on Sapphire Substrates with MOCVD

    Institute of Scientific and Technical Information of China (English)

    HU Yi-Fan; C.D. Beling; S. Fung

    2005-01-01

    @@ Depth profiled Doppler broadening of positron annihilation spectroscopy (DBPAS), which is also called the variable energy positron annihilation spectroscopy (VEPAS), is used in characterization of GaN grown on sapphire substrates with metal-organic chemical vapour deposition (MOCVD). The GaN film and the film/substrate interface are investigated. The VEPFIT (variable energy positron fit) software was used for analysing the data,and the positron diffusion length of the sapphire is obtained. The results suggest that there is a highly defected region near the GaN/sapphire interface. This thin dislocated region is generated at the film/substrate interface to relieve the strain. Effects of implantation dose on defect formation, for the GaN/Sapphire samples, which implanted by Al+ ions, are also investigated. Studies on Al+ implanted GaN films (not including the interface and sapphire) have revealed that there are two different regions of implantation damage. For the low Al+ implantation dose samples, in the region close to the surface, defects are mainly composed of vacancy pairs with small amount of vacancy clusters, and in the interior region of the film the positron traps are vacancy clusters without micro-voids. For the highest dose sample, however, some positron trap centres are in the form of micro-voids in the second region.

  1. Sapphire scintillation tests for cryogenic detectors in the Edelweiss dark matter search

    Energy Technology Data Exchange (ETDEWEB)

    Luca, M

    2007-07-15

    Identifying the matter in the universe is one of the main challenges of modern cosmology and astrophysics. An important part of this matter seems to be made of non-baryonic particles. Edelweiss is a direct dark matter search using cryogenic germanium bolometers in order to look for particles that interact very weakly with the ordinary matter, generically known as WIMPs (weakly interacting massive particles). An important challenge for Edelweiss is the radioactive background and one of the ways to identify it is to use a larger variety of target crystals. Sapphire is a light target which can be complementary to the germanium crystals already in use. Spectroscopic characterization studies have been performed using different sapphire samples in order to find the optimum doping concentration for good low temperature scintillation. Ti doped crystals with weak Ti concentrations have been used for systematic X ray excitation tests both at room temperature and down to 30 K. The tests have shown that the best Ti concentration for optimum room temperature scintillation is 100 ppm and 50 ppm at T = 45 K. All concentrations have been checked by optical absorption and fluorescence. After having shown that sapphire had interesting characteristics for building heat-scintillation detectors, we have tested if using a sapphire detector was feasible within a dark matter search. During the first commissioning tests of Edelweiss-II, we have proved the compatibility between a sapphire heat scintillation detector and the experimental setup. (author)

  2. The ongoing search for the oldest rock on the Danish island of Bornholm: new U-Pb zircon ages for a quartz-rich xenolith and country rock from the Svaneke Granite

    DEFF Research Database (Denmark)

    Waight, Tod Earle; Serre, Simon H.; Næsby, Sebastian H.

    2017-01-01

    -grained and quartz-rich and was likely derived from either a quartz-rich sedimentary protolith or a hydrothermally altered felsic volcanic rock. The relatively fine-grained felsic nature of the country rock gneiss and the presence of large zoned feldspars that may represent phenocrysts suggest its protolith may have...

  3. Intracavity quartz-enhanced photoacoustic sensor

    Energy Technology Data Exchange (ETDEWEB)

    Borri, S., E-mail: simone.borri@ino.it; Galli, I.; Mazzotti, D.; Giusfredi, G.; De Natale, P. [CNR-INO UOS Sesto Fiorentino and LENS, via Carrara 1, 50019 Sesto Fiorentino FI (Italy); Patimisco, P.; Scamarcio, G.; Spagnolo, V. [CNR-IFN UOS Bari and Dipartimento Interateneo di Fisica, Università degli Studi di Bari e Politecnico di Bari, via Amendola 173, 70126 Bari BA (Italy); Akikusa, N. [Development Bureau Laser Device R and D Group, Hamamatsu Photonics KK, Shizuoka 434-8601 (Japan); Yamanishi, M. [Central Research Laboratories, Hamamatsu Photonics KK, Shizuoka 434-8601 (Japan)

    2014-03-03

    We report on a spectroscopic technique named intracavity quartz-enhanced photoacoustic spectroscopy (I-QEPAS) employed for sensitive trace-gas detection in the mid-infrared spectral region. It is based on a combination of QEPAS with a buildup optical cavity. The sensor includes a distributed feedback quantum cascade laser emitting at 4.33 μm. We achieved a laser optical power buildup factor of ∼500, which corresponds to an intracavity laser power of ∼0.75 W. CO{sub 2} has been selected as the target molecule for the I-QEPAS demonstration. We achieved a detection sensitivity of 300 parts per trillion for 4 s integration time, corresponding to a noise equivalent absorption coefficient of 1.4 × 10{sup −8} cm{sup −1} and a normalized noise-equivalent absorption of 3.2 × 10{sup −10} W cm{sup −1} Hz{sup −1/2}.

  4. Optically stimulated luminescence sensitivity changes in quartz due to repeated use in single aliquot readout: Experiments and computer simulations

    DEFF Research Database (Denmark)

    McKeever, S.W.S.; Bøtter-Jensen, L.; Agersnap Larsen, N.

    1996-01-01

    As part of a study to examine sensitivity changes in single aliquot techniques using optically stimulated luminescence (OSL) a series of experiments has been conducted with single aliquots of natural quartz, and the data compared with the results of computer simulations of the type of processes...... believed to be occurring. The computer model used includes both shallow and deep ('hard-to-bleach') traps, OSL ('easy-to-bleach') traps, and radiative and non-radiative recombination centres. The model has previously been used successfully to account for sensitivity changes in quartz due to thermal...... trap and deep trap effects....

  5. Thermoluminescence (TL) spectra from quartz grains using on-line TL-spectrometric system

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, T.; Sugai, N.; Sakaue, H.; Shirai, N. [Niigata University, Niigata (Japan). Faculty of Science; Yasuda, K. [Daiwa Geological Laboratory Co. Ltd., Fukushima (Japan)

    1997-12-31

    An on-line spectrometric system installed with a small spectrometer and an image intensifier unit has been developed for weak and changeable TL-spectrum measurements with rising temperature for application to natural minerals. The detection sensitivity over visible wavelength regions was corrected using a known spectrum from a standard light source, and the detection sensitivity was also examined by a chemical luminol reaction. In an applied experiment, two quartz grain samples from two pyroclastic flows of the same origin, were subjected to testing with the present measuring system. The original data, consisting of 512 channels for every second at a constant heating rate of 1degC/s, were used to create a contour map or a 3-dimensional expression of TL-spectra after subtraction of background radiation. The artificially irradiated quartz grains clearly showed both red (RTL) and blue TL (BTL) in contrast to RTL alone from naturally accumulated TL. Both spectral expressions and glow curves from the same original data were found to be available to estimate quartz formation temperatures, together with thermoluminescence color images (TLCIs). 24 refs., 9 figs.

  6. Revelation of Causes of Colour Change in Beryllium-Treated Sapphires

    Institute of Scientific and Technical Information of China (English)

    Pichet Limsuwan; Siwaporn Meejoo; Asanee Somdee; Kheamrutai Thamaphat; Treedej Kittiauchawal; Atitaya Siripinyanond; Jurek Krzystck

    2008-01-01

    Blue sapphires are treated with Be in oxidizing atmosphere to change the blue colour into yellow. Untreated and Be-treated samples are examined using laser ablation inductively coupled-plasma-mass spectrometry (LA-ICP-MS), electron spin resonance (ESR) and ultraviolet-visible (UV-vis) spectroscopy. The results show that the yellow colouration in Be-heated blue sapphires is not due to Be diffusion from the surface of sapphire. Be behaves as a sole catalyst in this process. We find that the charge transfer between the ferrous (Fe2+) and ferric (Fe3+) is the reason of the colour change. The above conclusions are confirmed by ESR measurements to determine the connections between the Fe3+ ions before and after Be-treated heat treatments.

  7. Sapphire hard X-ray Fabry-Perot resonators for synchrotron experiments.

    Science.gov (United States)

    Tsai, Yi Wei; Wu, Yu Hsin; Chang, Ying Yi; Liu, Wen Chung; Liu, Hong Lin; Chu, Chia Hong; Chen, Pei Chi; Lin, Pao Te; Fu, Chien Chung; Chang, Shih Lin

    2016-05-01

    Hard X-ray Fabry-Perot resonators (FPRs) made from sapphire crystals were constructed and characterized. The FPRs consisted of two crystal plates, part of a monolithic crystal structure of Al2O3, acting as a pair of mirrors, for the backward reflection (0 0 0 30) of hard X-rays at 14.3147 keV. The dimensional accuracy during manufacturing and the defect density in the crystal in relation to the resonance efficiency of sapphire FPRs were analyzed from a theoretical standpoint based on X-ray cavity resonance and measurements using scanning electron microscopic and X-ray topographic techniques for crystal defects. Well defined resonance spectra of sapphire FPRs were successfully obtained, and were comparable with the theoretical predictions.

  8. High Temperature Testing with Sapphire Fiber White-Light Michelson Interferometers

    Science.gov (United States)

    Barnes, A.; Pedrazzani, J.; May, R.; Murphy, K.; Tran, T.; Coate, J.

    1996-01-01

    In the design of new aerospace materials, developmental testing is conducted to characterize the behavior of the material under severe environmental conditions of high stress, temperature, and vibration. But to test these materials under extreme conditions requires sensors that can perform in harsh environments. Current sensors can only monitor high temperature test samples using long throw instrumentation, but this is inherently less accurate than a surface mounted sensor, and provides no means for fabrication process monitoring. A promising alternative is the use of sapphire optical fiber sensors. Sapphire is an incredibly rugged material, being extremely hard (9 mhos), chemically inert, and having a melting temperature (over 2000 C). Additionally, there is a extensive background of optical fiber sensors upon which to draw for sapphire sensor configurations.

  9. Temperature and thermal stress evolutions in sapphire crystal during the cooling process by heat exchanger method

    Science.gov (United States)

    Ma, Wencheng; Zhao, Wenhan; Wu, Ming; Ding, Guoqiang; Liu, Lijun

    2017-09-01

    Transient numerical calculations were carried out to predict the evolutions of temperature and thermal stress in sapphire single crystal during the cooling process by heat exchanger method (HEM). Internal radiation in the semitransparent sapphire crystal was taken into account using the finite volume method (FVM) in the global heat transfer model. The numerical results seem to indicate that the narrow bottom region of the sapphire crystal is subjected to high thermal stress during the cooling process, which could be responsible for the seed cracking of the as-grown crystal, while the thermal stress is relatively small in the central main body of the crystal, and is less than 10 MPa during the whole cooling process. The fast decrease of the thermal stress in the bottom region of the crystal during the initial stage of cooling process is dominated by the reduction of the cooling helium gas in the heat exchanger shaft, and is not significantly affected by the heating power reduction rate.

  10. Rate of F center formation in sapphire under low-energy low-fluence Ar+ irradiation

    Science.gov (United States)

    Epie, E. N.; Wijesundera, D. N.; Tilakaratne, B. P.; Chen, Q. Y.; Chu, W. K.

    2016-03-01

    Ionoluminescence, optical absorption spectroscopy and Rutherford backscattering spectrometry channelling (RBS-C) have been used to study the rate of F center formation with fluence in 170 keV Ar+ irradiated single crystals of α-Al2O3 (sapphire) at room temperature. Implantation fluences range between 1013 cm-2 and 5 ×1014 cm-2. F center density (NF) has been found to display an initial rapid linear increase with Ar+ fluence followed by saturation to a maximum value of 1.74 ×1015 cm-2. Experimental results show a 1-1 correlation between radiation damage in the oxygen sublattice and F center density. This suggest F center kinetics in sapphire under low-energy low-fluence Ar irradiation is a direct consequence of dynamic competition between oxygen defect creation and recombination. An attempt has also been made to extend this discussion to F center kinetics in sapphire under swift heavy ion irradiation.

  11. Explosive volcanism and associated pressures - Implications for models of endogenically shocked quartz

    Science.gov (United States)

    De Silva, S. L.; Wolff, J. A.; Sharpton, V. L.

    1990-01-01

    The nature of explosive volcanic phenomena and associated pressures, both from field and theoretical perspectives, is discussed. An endogenic origin for shocked quartz at the K/T boundary requires impulsive pressures greater than 60 kbars to be generated during explosive volcanism. Explosive volcanic eruptions which are events of sustained decompression may be initiated by impulsive explosions while the magnitudes of the overpressures are small. These maximum overpressures can be controlled mainly by the tensile strength of the rock surrounding the magma chamber-conduit system. Thus maximum overpressures in the volcanic environment are limited to less than 500 bars which are orders of magnitude less than those required for shock quartz (greater than 60 kbars). This observation is found to be consistent with the complete lack of field or petrographic evidence in support of shock metamorphism associated with volcanic eruptions and their products.

  12. High-pressure sapphire cell for phase equilibria measurements of CO2/organic/water systems.

    Science.gov (United States)

    Pollet, Pamela; Ethier, Amy L; Senter, James C; Eckert, Charles A; Liotta, Charles L

    2014-01-24

    The high pressure sapphire cell apparatus was constructed to visually determine the composition of multiphase systems without physical sampling. Specifically, the sapphire cell enables visual data collection from multiple loadings to solve a set of material balances to precisely determine phase composition. Ternary phase diagrams can then be established to determine the proportion of each component in each phase at a given condition. In principle, any ternary system can be studied although ternary systems (gas-liquid-liquid) are the specific examples discussed herein. For instance, the ternary THF-Water-CO2 system was studied at 25 and 40 °C and is described herein. Of key importance, this technique does not require sampling. Circumventing the possible disturbance of the system equilibrium upon sampling, inherent measurement errors, and technical difficulties of physically sampling under pressure is a significant benefit of this technique. Perhaps as important, the sapphire cell also enables the direct visual observation of the phase behavior. In fact, as the CO2 pressure is increased, the homogeneous THF-Water solution phase splits at about 2 MPa. With this technique, it was possible to easily and clearly observe the cloud point and determine the composition of the newly formed phases as a function of pressure. The data acquired with the sapphire cell technique can be used for many applications. In our case, we measured swelling and composition for tunable solvents, like gas-expanded liquids, gas-expanded ionic liquids and Organic Aqueous Tunable Systems (OATS)(1-4). For the latest system, OATS, the high-pressure sapphire cell enabled the study of (1) phase behavior as a function of pressure and temperature, (2) composition of each phase (gas-liquid-liquid) as a function of pressure and temperature and (3) catalyst partitioning in the two liquid phases as a function of pressure and composition. Finally, the sapphire cell is an especially effective tool to gather

  13. A spectroscopic method for determining thickness of quartz wave plate

    Institute of Scientific and Technical Information of China (English)

    Weiwei Feng; Lihuang Lin; Ligang Chen; Huafeng Zhu; Ruxin Li; Zhizhan Xu

    2006-01-01

    A spectroscopic method to determine thickness of quartz wave plate is presented. The method is based on chromatic polarization interferometry. With the polarization-resolved transmission spectrum (PRTS)curve, the phase retardation of quartz wave plate can be determined at a wide spectral range from 200 to2000 nm obviously. Through accurate judgment of extreme points of PRTS curve at long-wave band, the physical thickness of quartz wave plates can be obtained exactly. We give a measuring example and the error analysis. It is found that the measuring precision of thickness is mainly determined by the spectral resolution of spectrometer.

  14. COMMENT: Comment on `Inhomogeneities and birefringence in quartz'

    Science.gov (United States)

    Saint-Grégoire, P.; Luk'yanchuk, I.

    1999-10-01

    We comment on the role of the novel incommensurate elongated-triangle (ELT) phase in the huge light scattering in quartz at small angles that was observed more than 40 years ago at the icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/>-icons/Journals/Common/beta" ALT="beta" ALIGN="TOP"/> phase transition and was associated with optical inhomogeneities of unknown nature. The relation of these inhomogeneities with the differently oriented ferroelastic blocks of the ELT phase proposed by us and co-workers in a previous publication was misinterpreted and criticized in a recent article by Aslanyan et al (Aslanyan T E, Shigenari T and Abe K 1998 J. Phys.: Condens. Matter 10 4577), who claimed also that the lock-in occurs at qicons/Journals/Common/neq" ALT="neq" ALIGN="TOP"/>0. Responding to their criticism, we claim that the ELT blocks do have ferroelastic properties which induce the inhomogeneities of optical indices and that the lock-in occurs at q = 0.

  15. Molecular Imprinting Technology in Quartz Crystal Microbalance (QCM) Sensors.

    Science.gov (United States)

    Emir Diltemiz, Sibel; Keçili, Rüstem; Ersöz, Arzu; Say, Rıdvan

    2017-02-24

    Molecularly imprinted polymers (MIPs) as artificial antibodies have received considerable scientific attention in the past years in the field of (bio)sensors since they have unique features that distinguish them from natural antibodies such as robustness, multiple binding sites, low cost, facile preparation and high stability under extreme operation conditions (higher pH and temperature values, etc.). On the other hand, the Quartz Crystal Microbalance (QCM) is an analytical tool based on the measurement of small mass changes on the sensor surface. QCM sensors are practical and convenient monitoring tools because of their specificity, sensitivity, high accuracy, stability and reproducibility. QCM devices are highly suitable for converting the recognition process achieved using MIP-based memories into a sensor signal. Therefore, the combination of a QCM and MIPs as synthetic receptors enhances the sensitivity through MIP process-based multiplexed binding sites using size, 3D-shape and chemical function having molecular memories of the prepared sensor system toward the target compound to be detected. This review aims to highlight and summarize the recent progress and studies in the field of (bio)sensor systems based on QCMs combined with molecular imprinting technology.

  16. Molecular Imprinting Technology in Quartz Crystal Microbalance (QCM Sensors

    Directory of Open Access Journals (Sweden)

    Sibel Emir Diltemiz

    2017-02-01

    Full Text Available Molecularly imprinted polymers (MIPs as artificial antibodies have received considerable scientific attention in the past years in the field of (biosensors since they have unique features that distinguish them from natural antibodies such as robustness, multiple binding sites, low cost, facile preparation and high stability under extreme operation conditions (higher pH and temperature values, etc.. On the other hand, the Quartz Crystal Microbalance (QCM is an analytical tool based on the measurement of small mass changes on the sensor surface. QCM sensors are practical and convenient monitoring tools because of their specificity, sensitivity, high accuracy, stability and reproducibility. QCM devices are highly suitable for converting the recognition process achieved using MIP-based memories into a sensor signal. Therefore, the combination of a QCM and MIPs as synthetic receptors enhances the sensitivity through MIP process-based multiplexed binding sites using size, 3D-shape and chemical function having molecular memories of the prepared sensor system toward the target compound to be detected. This review aims to highlight and summarize the recent progress and studies in the field of (biosensor systems based on QCMs combined with molecular imprinting technology.

  17. The Influence of Surface Anisotropy Crystalline Structure on Wetting of Sapphire by Molten Aluminum

    Science.gov (United States)

    Aguilar-Santillan, Joaquin

    2013-05-01

    The wetting of sapphire by molten aluminum was investigated by the sessile drop technique from 1073 K to 1473 K (800 °C to 1200 °C) at PO2 <10-15 Pa under Ar atmosphere. This study focuses on sapphire crystalline structure and its principle to the interface. The planes " a" and " b" are oxygen terminated structures and wet more by Al, whereas the " c" plane is an aluminum terminated structure. A wetting transition at 1273 K (1000 °C) was obtained and a solid surface tension proves the capillarity trends of the couple.

  18. Synthesis of ZnO nanocrystals in sapphire by ion implantation and vacuum annealing

    Science.gov (United States)

    Marques, C.; Franco, N.; Alves, L. C.; da Silva, R. C.; Alves, E.; Safran, G.; McHargue, C. J.

    2007-04-01

    The synthesis of embedded ZnO nanoparticles in m-cut sapphire was achieved through high fluence Zn ion implantation, 0.9 × 1017 cm-2 at room temperature, followed by annealing at 1000 °C in vacuum. In c-cut samples subjected to similar annealing conditions only buried precipitates of Zn form. TEM results in these samples show a high concentration of faceted precipitates distributed along the c-plane and the presence of Kirkendall voids distributed along the entire implanted region. In both cases a strong loss of Zn is observed upon annealing, which depends on the sapphire host orientation.

  19. Tunable Sum Frequency Mixing of a Ti∶sapphire Laser and a Nd∶YAG Laser

    Institute of Scientific and Technical Information of China (English)

    DING Xin; YAO Jianquan; YU Yizhong; YU Xuanyi; XU Jingjun; ZHANG Guangyin

    2001-01-01

    In this paper the theoretical and experimental results of sum-frequency mixing of a Ti∶sapphire laser and a 1.064 μm Nd∶YAG laser are presented. By using two KTP crystals cut at θ=76° and 85° (φ=90° in both crystals), respectively, the sum-frequency mixing tuning range from 459.3 to 509.6 nm in one Ti∶sapphire laser setup is experimentally achieved. The maximum output energy was 14.6 mJ and the energy conversion efficiency was up to 15.2%.

  20. Synthesis of ZnO nanocrystals in sapphire by ion implantation and vacuum annealing

    Energy Technology Data Exchange (ETDEWEB)

    Marques, C. [LFI, Dep. Fisica, Instituto Tecnologico e Nuclear, E.N. 10, 2686-953 Sacavem (Portugal); Centro Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisbon (Portugal); Franco, N. [LFI, Dep. Fisica, Instituto Tecnologico e Nuclear, E.N. 10, 2686-953 Sacavem (Portugal); Centro Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisbon (Portugal); Alves, L.C. [LFI, Dep. Fisica, Instituto Tecnologico e Nuclear, E.N. 10, 2686-953 Sacavem (Portugal); Centro Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisbon (Portugal); Silva, R.C. da [LFI, Dep. Fisica, Instituto Tecnologico e Nuclear, E.N. 10, 2686-953 Sacavem (Portugal) and Centro Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisbon (Portugal); Alves, E. [LFI, Dep. Fisica, Instituto Tecnologico e Nuclear, E.N. 10, 2686-953 Sacavem (Portugal) and Centro Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisbon (Portugal)]. E-mail: ealves@itn.pt; Safran, G. [Research Institute for Technical Physics and Materials Science, H-1525 Budapest (Hungary); McHargue, C.J. [University of Tennessee, Knoxville, TN 37996-0750 (United States)

    2007-04-15

    The synthesis of embedded ZnO nanoparticles in m-cut sapphire was achieved through high fluence Zn ion implantation, 0.9 x 10{sup 17} cm{sup -2} at room temperature, followed by annealing at 1000 deg. C in vacuum. In c-cut samples subjected to similar annealing conditions only buried precipitates of Zn form. TEM results in these samples show a high concentration of faceted precipitates distributed along the c-plane and the presence of Kirkendall voids distributed along the entire implanted region. In both cases a strong loss of Zn is observed upon annealing, which depends on the sapphire host orientation.

  1. Birefringence measurements in single crystal sapphire and calcite shocked along the a axis

    Science.gov (United States)

    Tear, Gareth R.; Chapman, David J.; Eakins, Daniel E.; Proud, William G.

    2017-01-01

    Calcite and sapphire were shock compressed along the direction (a axis) in a plate impact configuration. Polarimetery and Photonic Doppler Velocimetery (PDV) were used to measure the change in birefringence with particle velocity in the shock direction. Results for sapphire agree well with linear photoelastic theory and current literature showing a linear relationship between birefringence and particle velocity up to 310 m s-1. A maximum change in birefringence of 5% was observed. Calcite however showed anomolous behaviour with no detectable change in birefringence (less than 0.1%) over the range of particle velocities studied (up to 75 m s-1).

  2. Intracavity frequency doubling of CW Ti:Sapphire laser utilising BiBO nonlinear crystal

    DEFF Research Database (Denmark)

    Thorhauge, Morten; Mortensen, Jesper Liltorp; Tidemand-Lichtenberg, Peter

    Utilising BiBO nonlinear crystal frequency doubling a Ti:Sapphire CW laser gave 100 mW at 405 nm and 53 mW at 392 nm. Stability proved excellent without servo control. Broad tunability was shown around 392 nm.......Utilising BiBO nonlinear crystal frequency doubling a Ti:Sapphire CW laser gave 100 mW at 405 nm and 53 mW at 392 nm. Stability proved excellent without servo control. Broad tunability was shown around 392 nm....

  3. Behaviors of optical and chemical state of Nb+ implanted sapphire after annealing

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The behavior of the radiation damage of sapphire crystal, produced by implantation with 380 keV Nb+ ion followed by annealing in a series of steps from 500 to 1100℃C at reducing atmosphere, was investigated in optical absorption and XPS measurements. It is found that the implanted niobium in sapphire is in different local environments with different chemical states after the annealing. The changes in optical density (OD) from the bands, based on the well known F-type centers, show that the annealing behavior of the radiation damage may be divided into different stages due to different mechanisms.

  4. Measurement for titanium density distribution on Ti:sapphire rods for high intensity pump source

    Energy Technology Data Exchange (ETDEWEB)

    Usami, Tsutomu; Nishimura, Akihiko; Sugiyama, Akira [Japan Atomic Energy Research Inst., Kizu, Kyoto (Japan). Kansai Research Establishment

    2001-10-01

    A Ti:sapphire rod of 190 mm length made by Czochralski (CZ) technique was used in the flashlamp pumped high intensity laser for Yb:glass chirped pulse amplification. In the absorption spectroscopy of the rod immersed in an index matching liquid of methylene iodide, heterogeneous Ti{sup 3+} density distribution was measured along the direction of length. It has been first clarified that the Ti:sapphire rod grown by the CZ technique has 20% difference of the Ti{sup 3+} density at the both ends. (author)

  5. Sapphire: Relation between luminescence of starting materials and luminescence of single crystals

    Science.gov (United States)

    Mogilevsky, R.; Nedilko, S.; Sharafutdinova, L.; Burlay, S.; Sherbatskii, V.; Boyko, V.; Mittl, S.

    2009-10-01

    A relation between photoluminescence (PL) characteristics of different starting materials used for crystal growth and un-doped sapphire single crystals manufactured using various methods of crystal growth (Kyropolus, HEM, Czochralski, and EFG) was found. The crystals grown using the Verneuil starting material exhibited significant PL when any method of crystal growth was used. On the contrary, sapphire samples grown by the same technologies wherein the starting material was EMT HPDA R revealed very low PL. (HPDA R is produced by EMT, Inc., with proprietary and patented technology.)

  6. Using a titanium-in-quartz geothermometer for crystallization temperature estimation of the Palaeoproterozoic Suursaari quartz porphyry

    Directory of Open Access Journals (Sweden)

    Kairi Ehrlich

    2012-11-01

    Full Text Available The Suursaari volcanic sequence represents volcanic activity related to Wiborg Batholith rapakivi intrusions in the southern part of the Fennoscandian Shield. The estimated pressure conditions for batholith granitic rocks are 1–5 kbar and crystallization temperatures range from 670 to 890 °C. To describe the temperature regime of the Suursaari volcanic system, a rock sample was taken from the Mäkiinpäällys Mountain outcrop and analysed with laser ablation inductively coupled plasma mass spectrometry. Sample spots were selected from quartz phenocrysts and groundmass. Quartz crystallization temperatures were calculated by the Ti-in-quartz method that takes into account rutile equilibrium and Ti activity in each phase. The calculated crystallization temperatures of the Suursaari quartz porphyry are in the range of 647–738 °C. The results show that the Suursaari quartz porphyry contains two generations of quartz which can be distinguished on the basis of crystallization temperatures: phenocrysts crystallized at higher and groundmass quartz at lower temperature.

  7. Weight of Production of Emeralds, Rubies, Sapphires, and Tanzanite from 1995 Through 2005

    Science.gov (United States)

    Yager, Thomas R.; Menzie, W. David; Olson, Donald W.

    2008-01-01

    U.S. Geological Survey (USGS) historically has not attempted to report comprehensive world production of gemstones on a country basis. This was because estimation of gemstone production is inherently difficult due to the fragmentary nature of the industry, the lack of governmental oversight or reporting in many countries where colored gemstones are mined, and the wide variation in quality between individual gemstones. Unlike diamonds, which, with the exception of the alluvial stones of West Africa, are mainly produced by large international mining companies and evaluated, cut, and marketed through a highly developed pricing structure and complex commercial arrangements, colored gemstones are mainly mined by individuals or small companies and have less developed evaluation and marketing arrangements. The trading centers for colored gems are smaller and less well known than the diamond centers. Colored gemstones, like alluvial diamonds, have the potential to be used to fund civil conflicts and other illegal activities, and because trade in colored gemstones is less organized than that of diamonds, they offer less opportunity for effective regulation of their trade. And, like diamond, until the recent advent of the Kimberley Process no generally accepted estimates of colored gemstone production globally or by producing country have existed. The present paper is a first attempt to develop production statistics for the three precious gems -emeralds, rubies, and sapphires - and tanzanite tanzanite, a semi-precious gem. The data consist of the weight of production of each of the gemstones from 1995 through 2005. Preliminary data on the weights of gemstone production were presented as a poster session at the Gemological Institute of America's Gemological Research Conference in San Diego, CA, in 2006, and as a published abstract (Yager, 2006) in an attempt to gather response to the estimates. The USGS continues to welcome information and suggestions that would improve the

  8. Structure optimization and simulation analysis of the quartz micromachined gyroscope

    Science.gov (United States)

    Wu, Xuezhong; Wang, Haoxu; Xie, Liqiang; Dong, Peitao

    2014-03-01

    Structure optimization and simulation analysis of the quartz micromachined gyroscope are reported in this paper. The relationships between the structure parameters and the frequencies of work mode were analysed by finite element analysis. The structure parameters of the quartz micromachined gyroscope were optimized to reduce the difference between the frequencies of the drive mode and the sense mode. The simulation results were proved by testing the prototype gyroscope, which was fabricated by micro-electromechanical systems (MEMS) technology. Therefore, the frequencies of the drive mode and the sense mode can match each other by the structure optimization and simulation analysis of the quartz micromachined gyroscope, which is helpful in the design of the high sensitivity quartz micromachined gyroscope.

  9. Origin of organism-dependent biogenic silica quartz formation.

    Science.gov (United States)

    Sato, Kiminori

    2011-12-15

    Organism-dependent biogenic quartz formation in the steady-state environment is a phenomenon that can address the global environmental issues such as diagenetic evolution, biogeochemical cycling, and reservoir formation, but detailed studies have not been performed so far. Here, steady-state quartz formation is studied for amorphous silica of different biogenic origin on the basis of the recently established mechanistic model [Sato et al., J. Phys. Chem. C 2011, 115, 18131]. Amorphous silica originated from rice husks possesses angstrom-scale pores larger by 1.3 Å than those originated from diatom algae. The slight difference of pore size dramatically reduces activation energies of water diffusion by 78% and reactions of water molecules at pore surfaces by 47%, resulting in the reduction of activation energy of biogenic quartz formation by 64%. The present findings evidence that angstrom-scale pores intrinsically residing in the amorphous matrix are the organism-dependent origin of steady-state biogenic quartz formation.

  10. Degradation of glycine and alanine on irradiated quartz.

    Science.gov (United States)

    Pawlikowski, Maciej; Benko, Aleksandra; Wróbel, Tomasz P

    2013-04-01

    Recent researches suggest participation of minerals in the formation of life under primordial conditions. Among all of the minerals, quartz seems to be one of the most probable to take part in such processes. However, an external source of energy is needed, e.g. electric discharge. A device simulating the proposed conditions was designed and was used to simulate prebiotic conditions. Investigation of processes occurring during the stimulation of quartz with electric discharge was studied by means of Ultraviolet-visible (UV-VIS) spectroscopy, in order to monitor the generation kinetics of free radicals. Additionally, infrared spectroscopy was applied to identify chemical reaction products created in a solution of alanine or glycine, in the presence of quartz treated with electric discharge. Formation of increased amounts of free radicals, compared to experiments performed without quartz and/or amino acid, is reported, along with identification of possible degradation products of alanine. No synthetic reactions were observed.

  11. Quartz Fibers For Laser Therapy In Tissue Contact

    Science.gov (United States)

    Lenz, P.; Sabber, G.; Lambert, R.; Berger, F.

    1984-03-01

    Quartz fibers not protected by a gas stream and used in tissue contact can work virtually indefinitely due to "self cleaning" and "regeneration". Tissue lesions are similar to those obtained with conventional devices.

  12. Structure optimization and simulation analysis of the quartz micromachined gyroscope

    Directory of Open Access Journals (Sweden)

    Xuezhong Wu

    2014-02-01

    Full Text Available Structure optimization and simulation analysis of the quartz micromachined gyroscope are reported in this paper. The relationships between the structure parameters and the frequencies of work mode were analysed by finite element analysis. The structure parameters of the quartz micromachined gyroscope were optimized to reduce the difference between the frequencies of the drive mode and the sense mode. The simulation results were proved by testing the prototype gyroscope, which was fabricated by micro-electromechanical systems (MEMS technology. Therefore, the frequencies of the drive mode and the sense mode can match each other by the structure optimization and simulation analysis of the quartz micromachined gyroscope, which is helpful in the design of the high sensitivity quartz micromachined gyroscope.

  13. Low-temperature intracrystalline deformation microstructures in quartz

    NARCIS (Netherlands)

    Derez, Tine; Pennock, Gill; Drury, Martyn; Sintubin, Manuel

    A review of numerous genetic interpretations of the individual low-temperature intracrystalline deformation microstructures in quartz shows that there is no consensus concerning their formation mechanisms. Therefore, we introduce a new, purely descriptive terminology for the three categories of

  14. The Characteristics of the Shear-Vibrating Quartz Crystal Resonator

    Institute of Scientific and Technical Information of China (English)

    Wenjie Tian; Lingling Liu; Junling Lu; Fuxue Zhang

    2006-01-01

    According to the piezoelectric equation and the vibration theory of the quartz crystal, the relations between the vibrating frequency and structural parameters under the thickness-shear-vibration of AT-cut quartz crystal have been studied.The frequency conditions under which quartz crystal resonator formed stationary wave inside the electrode district and the transmission characteristics of wave outside the electrode district have also been discussed. A quartz crystal resonator was developed based on this analysis. The experiment showed that the force-sensing characteristics were independent of the fixation of the crystal edge. The detecting distinguish ability was up to 0.001 °, and the short-term frequency stability was up to 1.38x 10-10/min.

  15. Influence of quartz particles on wear in vertical roller mills

    DEFF Research Database (Denmark)

    Jensen, Lucas R.D.; Friis, Henrik; Fundal, Erling;

    2010-01-01

    statistical planning, a total of 10 tests were arried out with two different limestones and one type of quartz sand. The size distributions were kept constant and only the mixing ratios were varied. It appears from the investigation that mixtures consisting of minerals with different grindabilities result...... in an increased concentration of abrasive particles in the grinding bed ðR2 > 0:99Þ. The present study shows that the quartz concentration in the grinding bed is determining the wear rate....

  16. Average life of oxygen vacancies of quartz in sediments

    Institute of Scientific and Technical Information of China (English)

    DIAO; Shaobo(刁少波); YE; Yuguang(业渝光)

    2002-01-01

    Average life of oxygen vacancies of quartz in sediments is estimated by using the ESR (electron spin resonance) signals of E( centers from the thermal activation technique. The experimental results show that the second-order kinetics equation is more applicable to the life estimation compared with the first order equation. The average life of oxygen vacancies of quartz from 4895 to 4908 deep sediments in the Tarim Basin is about 1018 a at 27℃.

  17. Interaction Between Graphene Oxide Nanoparticles and Quartz Sand.

    Science.gov (United States)

    Sotirelis, Nikolaos P; Chrysikopoulos, Constantinos V

    2015-11-17

    In this study, the influence of pH, ionic strength (IS), and temperature on graphene oxide (GO) nanoparticles attachment onto quartz sand were investigated. Batch experiments were conducted at three controlled temperatures (4, 12, and 25 °C) in solutions with different pH values (pH 4, 7, and 10), and ionic strengths (IS = 1.4, 6.4, and 21.4 mM), under static and dynamic conditions. The surface properties of GO nanoparticles and quartz sand were evaluated by electrophoretic mobility measurements. Derjaguin-Landau-Verwey-Overbeek (DLVO) potential energy profiles were constructed for the experimental conditions, using measured zeta potentials. The experimental results showed that GO nanoparticles were very stable under the experimental conditions. Both temperature and pH did not play a significant role in the attachment of GO nanoparticles onto quartz sand. In contrast, IS was shown to influence attachment. The attachment of GO particles onto quartz sand increased significantly with increasing IS. The experimental data were fitted nicely with a Freundlich isotherm, and the attachment kinetics were satisfactorily described with a pseudo-second-order model, which implies that the quartz sand exhibited substantial surface heterogeneity and that GO retention was governed by chemisorption. Furthermore, thermodynamic analysis revealed that the attachment process was nonspontaneous and endothermic, which may be associated with structural changes of the sand surfaces due to chemisorption. Therefore, secondary minimum interaction may not be the dominant mechanism for GO attachment onto the quartz sand under the experimental conditions.

  18. Basic characteristics of quartz crystal sensor with interdigitated electrodes

    Directory of Open Access Journals (Sweden)

    Hiroshi Muramatsu

    2016-03-01

    Full Text Available This paper describes basic characteristics of the quartz crystal sensor with interdigitated electrodes (IDE quartz crystal sensor which is for simultaneous monitoring of mass, viscosity, conductivity and dielectric changes of liquids or thin films. As the IDE quartz crystal sensor has three terminals for a pair of IDEs on the one side and a counter electrode on the other side, the resonance properties have been analyzed using the electrical equivalent circuit models and measured experimentally for all connecting types of electrode pairs. The IDE quartz crystal has shown clear resonance curves for calculating the resonance frequency and resonance resistance values as well as normal quartz crystal in the air and in contact with liquid. Small shifts in the resonance frequency and resonance resistance depending on the connecting types have been obtained and analyzed using the equivalent circuit models. We have found the integrated quartz crystal and IDE sensors could be monitored simultaneously by only one impedance analyzer. Finally, two types of measuring systems have been demonstrated for continuous measuring methods.

  19. The Planning Research of Zhaoqing City Water System and Water Landscape Based on Respecting Nature and History——An Example from Zhaoqing Ancient River to the"Sapphire Necklace"%基于尊重自然和历史的肇庆市城市水系与水景观规划研究——从肇庆的古河道到"蓝宝石项链"

    Institute of Scientific and Technical Information of China (English)

    钟国庆; 陈学年

    2011-01-01

    Based on the background of city planning problems in Zhaoqing, and by reviewing frontier theories and cases of landscape planning in the world, the formation of ancient rivers of Zhaoqing, and the process of the ancient river becoming urban wetland are analyzed.The landscape value of water system and culture, and the significance of protection are studied.Ideas and plans to protect and utilize the wetland water system are presented.The plan of building Zhaoqing's "sapphire necklace" is of great importance for Zhaoqing to build itself into a livable city, develop leisure and tourism and improve the ecological environment, which will set an example for other cities.%基于肇庆市城市规划中存在的问题的背景,分析肇庆古河道的形成、古河道变成城市湿地的过程.研究水系的景观和文化价值,以及保护的意义,提出保护和利用湿地水系的心路与方案,规划肇庆的"蓝宝石项链",对建设肇庆成为宜居城市、发展休闲旅游和改善生态环境有重大意义,且对我国其他城市的建设也有借鉴意义.

  20. Femtosecond Ti:sapphire cryogenic amplifier with high gain and MHz repetition rate

    DEFF Research Database (Denmark)

    Dantan, Aurelien Romain; Laurat, Julien; Ourjoumtsev, Alexei

    2007-01-01

    We demonstrate high gain amplification of 160-femtosecond pulses in a compact double-pass cryogenic Ti:sapphire amplifier. The setup involves a negative GVD mirrors recompression stage, and operates with a repetition rate between 0.2 and 4 MHz with a continuous pump laser. Amplification factors...

  1. Fully-depleted silicon-on-sapphire and its application to advanced VLSI design

    Science.gov (United States)

    Offord, Bruce W.

    1992-01-01

    In addition to the widely recognized advantages of full dielectric isolation, e.g., reduced parasitic capacitance, transient radiation hardness, and processing simplicity, fully-depleted silicon-on-sapphire offers reduced floating body effects and improved thermal characteristics when compared to other silicon-on-insulator technologies. The properties of this technology and its potential impact on advanced VLSI circuitry will be discussed.

  2. Deep-ultraviolet frequency metrology with a narrowband titanium:sapphire laser

    NARCIS (Netherlands)

    Hannemann, S.

    2007-01-01

    Within the framework of this thesis resaerch project a narrow band titanium:sapphire laser was built. It provides nanosecond pulses that are subsequently upconverted to the deep ultraviolet frequency range. Absolute frequency calibration is achieved by linking the injection seeding light to a

  3. Low Temperature Rhombohedral Single Crystal SiGe Epitaxy on c-plane Sapphire

    Science.gov (United States)

    Duzik, Adam J.; Choi, Sang H.

    2016-01-01

    Current best practice in epitaxial growth of rhombohedral SiGe onto (0001) sapphire (Al2O3) substrate surfaces requires extreme conditions to grow a single crystal SiGe film. Previous models described the sapphire surface reconstruction as the overriding factor in rhombohedral epitaxy, requiring a high temperature Al-terminated surface for high quality films. Temperatures in the 850-1100 C range were thought to be necessary to get SiGe to form coherent atomic matching between the (111) SiGe plane and the (0001) sapphire surface. Such fabrication conditions are difficult and uneconomical, hindering widespread application. This work proposes an alternative model that considers the bulk sapphire structure and determines how the SiGe film nucleates and grows. Accounting for thermal expansion effects, calculations using this new model show that both pure Ge and SiGe can form single crystal films in the 450-550 C temperature range. Experimental results confirm these predictions, where x-ray diffraction and atomic force microscopy show the films fabricated at low temperature rival the high temperature films in crystallographic and surface quality. Finally, an explanation is provided for why films of comparable high quality can be produced in either temperature range.

  4. Laser-assisted microstructuring for Ti:sapphire channel-waveguide fabrication

    NARCIS (Netherlands)

    Crunteanu, A.; Pollnau, Markus; Jänchen, G.; Hibert, C.; Hoffmann, P.; Salathé, R.P.; Eason, R.W.; Shepherd, D.P.

    We report on the fabrication of Ti:sapphire channel waveguides. Such channel waveguides are of interest, e.g., as low-threshold tunable lasers. We investigated several structuring methods including ion beam implantation followed by wet chemical etching strip loading by polyimide spin coating and

  5. Study on Inclusions in Large Sapphire Optical Crystal Grown by SAPMAC Method

    Institute of Scientific and Technical Information of China (English)

    WANG Gui-gen; ZHANG Ming-fu; ZUO Hong-bo; HE Xiao-dong; HAN Jie-cai

    2006-01-01

    The sapphire (Al2O3) single crystal is a kind of excellent infrared transmission window materials. A large-sized sapphire (Φ225 mm×205 mm, 27.5 kg) was grown by SAPMAC method (sapphire growth technique with micro-pulling and shoulder-expanding at cooled center). Several kinds of inclusion in the large sapphire crystal were investigated by means of an optical microscopy (OM), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The experimental results show that most inclusions are consisted of solid metallic and non-metallic particles as well as gas pores caused by the impurity of alumina as the raw material, the thermal dissociation of aluminum oxide melt and the reaction of the melt to the crucible material (Mo) at high temperatures. It is also found that in different crystal regions the inclusions are of varied sizes, morphology and chemical compositions. Finally, the measures to reduce and eliminate the inclusions are proposed to improve the crystal quality.

  6. Neutron reflectivity study of substrate surface chemistry effects on supported phospholipid bilayer formation on (1120) sapphire.

    Energy Technology Data Exchange (ETDEWEB)

    Oleson, Timothy A. [University of Wisconsin, Madison; Sahai, Nita [University of Akron; Wesolowski, David J [ORNL; Dura, Joseph A [ORNL; Majkrzak, Charles F [ORNL; Giuffre, Anthony J. [University of Wisconsin, Madison

    2012-01-01

    Oxide-supported phospholipid bilayers (SPBs) used as biomimetric membranes are significant for a broad range of applications including improvement of biomedical devices and biosensors, and in understanding biomineralization processes and the possible role of mineral surfaces in the evolution of pre-biotic membranes. Continuous-coverage and/or stacjed SPBs retain properties (e.,g. fluidity) more similar to native biological membranes, which is desirable for most applications. Using neutron reflectivity, we examined face coverage and potential stacking of dipalmitoylphosphatidylcholine (DPPC) bilayers on the (1120) face of sapphire (a-Al2O3). Nearly full bilayers were formed at low to neutral pH, when the sapphire surface is positively charged, and at low ionic strength (l=15 mM NaCl). Coverage decreased at higher pH, close to the isoelectric point of sapphire, and also at high I>210mM, or with addition of 2mM Ca2+. The latter two effects are additive, suggesting that Ca2+ mitigates the effect of higher I. These trends agree with previous results for phospholipid adsorption on a-Al2O3 particles determined by adsorption isotherms and on single-crystal (1010) sapphire by atomic force microscopy, suggesting consistency of oxide surface chemistry-dependent effects across experimental techniques.

  7. High-power solid-state sapphire whispering gallery mode maser.

    Science.gov (United States)

    Creedon, Daniel L; Benmessaï, Karim; Tobar, Michael E; Hartnett, John G; Bourgeois, Pierre-Yves; Kersale, Yann; Le Floch, Jean-Michel; Giordano, Vincent

    2010-03-01

    We present new results on a cryogenic solid-state maser frequency standard, which relies on the excitation of whispering gallery (WG) modes within a doped monocrystalline sapphire resonator (alpha-Al2O3). Included substitutively within the highest purity HEMEX-grade sapphire crystal lattice are Fe2+ impurities at a concentration of parts per million, an unavoidable result of the manufacturing process. Mass conversion of Fe2+ to Fe3+ ions was achieved by thermally annealing the sapphire in air. Above-threshold maser oscillation was then excited in the resonator at zero applied DC magnetic field by pumping high-Q WG modes coincident in frequency with the electron spin resonance (ESR) energy levels of the Fe3+ spin population. A 2 stage annealing process was undertaken for a sapphire resonator with exceptionally low Fe3+ concentration, resulting in an improvement of 6 orders of magnitude in output power for this particular crystal, and exceeding the previous best implementation of our scheme in another crystal by nearly 20 dB. This represents an output signal 7 orders of magnitude more powerful than a typical commercial hydrogen maser. At this power level, we estimate a limit on the frequency stability of order 1 x 10(-17)/square root(tau) due to the Schawlow-Townes fundamental thermal noise limit.

  8. Multiphoton imaging with a novel compact diode-pumped Ti:sapphire oscillator

    DEFF Research Database (Denmark)

    König, Karsten; Andersen, Peter E.; Le, Tuan;

    2015-01-01

    Multiphoton laser scanning microscopy commonly relies on bulky and expensive femtosecond lasers. We integrated a novel minimal-footprint Ti:sapphire oscillator, pumped by a frequency-doubled distributed Bragg reflector tapered diode laser, into a clinical multiphoton tomograph and evaluated its...

  9. New sapphire and ruby components and their manufacture using diamond abrasives

    Science.gov (United States)

    Sauser, D.

    The properties of synthetic aluminum oxides (sapphire and ruby) and their applications in watchmaking (watch bearings and watchglasses) and as hard-wearing components such as centering devices for optical fibres and water jet nozzles for material cutting are discussed. Examples are given of the use of diamonds tools for machining such components, including sawing, drilling, grinding and polishing operations.

  10. "You Hafta Push": Using Sapphire's Novel to Teach Introduction to American Government

    Science.gov (United States)

    Pappas, Christine

    2007-01-01

    Using fiction in the classroom can dramatize public policy issues and political science concepts, therefore, making them more real and relevant to students. Sapphire's 1996 novel "Push" puts a face on welfare, rape, incest, child abuse, educational inequalities, homophobia, and AIDS. I also use this novel to discuss the public policy process,…

  11. Thermal Stresses and Cracks During the Growth of Large-sized Sapphire with SAPMAC Method

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The finite-element method has been used to study the thermal stress distribution in large-sized sapphire crystals grown with the sapphire growth technique with micro-pulling and shoulder-expanding at cooled center (SAPMAC) method. A critical defect model has been established to explain the growth and propagation of cracks during the sapphire growing process. It is demonstrated that the stress field depends on the growth rate, the ambient temperature and the crystallizing direction. High stresses always exist near the growth interfaces, at the shoulder-expanding locations, the tailing locations and the sites where the diameters undergo sharp changes. The maximum stresses always occur at the interface of seeds and crystals. Cracks often form in the critical defect region and spread in the m-planes and a-planes under applied tensile stresses during crystal growth. The experimental results have verified that with the improved system of crystal growth and well-controlled techniques, the large-sized sapphire crystals of high quality can be grown due to absence of cracks.

  12. A century of sapphire crystal growth: origin of the EFG method

    Science.gov (United States)

    Harris, Daniel C.

    2009-08-01

    A. Verneuil developed flame fusion to grow sapphire and ruby on a commercial scale around 1890. Flame fusion was further perfected by Popov in the Soviet Union in the 1930s and by Linde Air Products Co. in the U.S. during World War II. Union Carbide Corp., the successor to Linde, developed Czochralski crystal growth for sapphire laser materials in the 1960s. Edge-Defined Film-Fed Growth (EFG) was invented by H. Labelle in the 1960s and the Heat Exchanger Method (HEM) was invented by F. Schmid and D. Viechnicki in 1967. Both methods were commercialized in the 1970s. Gradient solidification was invented in Israel in the 1970s by J. Makovsky. The Horizontal Directional Solidification Method (HDSM) was invented by Kh. S. Bagdasorov in the Soviet Union in the 1960s. Kyropoulos growth of sapphire, known as GOI crystal growth in the Soviet Union, was developed by M. Musatov at the State Optical Institute in St. Petersburg in the 1970s. Today, half of the world's sapphire is produced by the GOI method.

  13. On modifications of fluid inclusions in quartz : re-equilibration experiments and thermodynamical calculations on fluids in natural quartz

    NARCIS (Netherlands)

    Bakker, R.J.

    1992-01-01

    Fluids in rocks can be traced to great depths, and are found in crustal rocks as well as in mantle rocks. Information about the deep fluid which is obtained from fluid inclusions must be handled with care, for the way up after entrapment in a crystal is long and full of interferences at different pr

  14. Quartz concentration trends in metal and nonmetal mining.

    Science.gov (United States)

    Watts, Winthrop F; Huynh, Tran B; Ramachandran, Gurumurthy

    2012-01-01

    From 1974 through 2010, the Mine Safety and Health Administration (MSHA) collected nearly 147,000 respirable dust samples with a mass of at least 0.1 mg and a minimum of 1% quartz. These samples represent about 50% of all respirable dust compliance samples collected by MSHA. Analysis of these data shows that pockets of high concentrations and overexposure continue to exist. At underground mines, from 2005 to 2010, occupations with >20% of the samples exceeding the permissible exposure limit (PEL) and geometric mean quartz concentrations exceeding the ACGIH threshold limit value of 25 μg/m(3) included mucking, crusher operator, general laborer/utility, and front-end loader operator. During the same period, stone and rock saw operators and bagger and packers working at surface mines and mills also had >20% of the samples exceeding the PEL and geometric mean quartz concentrations >25 μg/m(3). Regardless of mine type or location, slow but steady improvement in exposure levels is seen in jobs involving crushing operations, which are widespread in the mining industry. Crusher operators are more likely to work in an enclosed area where it is easier to apply dust controls and air conditioning. A downward trend is also observed for vehicle equipment operators who drive load-haul-dumps, front-end loaders, trucks, and similar equipment. Crusher operators and vehicle equipment operators represent occupational categories that are widely sampled by MSHA inspectors. A small but statistically significant reduction in the overall mean respirable quartz dust and quartz concentrations from 1993 to 2010 was observed in most commodity groups. Variability from year to year and between commodities is high. Reduction in respirable quartz dust concentration does not necessarily correspond to a reduction in quartz concentration within the same commodity group. These trends are consistent with those reported in previous studies.

  15. Treated and untreated rock dust: Quartz content and physical characterization.

    Science.gov (United States)

    Soo, Jhy-Charm; Lee, Taekhee; Chisholm, William P; Farcas, Daniel; Schwegler-Berry, Diane; Harper, Martin

    2016-11-01

    Rock dusting is used to prevent secondary explosions in coal mines, but inhalation of rock dusts can be hazardous if the crystalline silica (e.g., quartz) content in the respirable fraction is high. The objective of this study is to assess the quartz content and physical characteristics of four selected rock dusts, consisting of limestone or marble in both treated (such as treatment with stearic acid or stearates) and untreated forms. Four selected rock dusts (an untreated and treated limestone and an untreated and treated marble) were aerosolized in an aerosol chamber. Respirable size-selective sampling was conducted along with particle size-segregated sampling using a Micro-Orifice Uniform Deposit Impactor. Fourier Transform Infrared spectroscopy and scanning electron microscopy with energy-dispersive X-ray (SEM-EDX) analyses were used to determine quartz mass and particle morphology, respectively. Quartz percentage in the respirable dust fraction of untreated and treated forms of the limestone dust was significantly higher than in bulk samples, but since the bulk percentage was low the enrichment factor would not have resulted in any major change to conclusions regarding the contribution of respirable rock dust to the overall airborne quartz concentration. The quartz percentage in the marble dust (untreated and treated) was very low and the respirable fractions showed no enrichment. The spectra from SEM-EDX analysis for all materials were predominantly from calcium carbonate, clay, and gypsum particles. No free quartz particles were observed. The four rock dusts used in this study are representative of those presented for use in rock dusting, but the conclusions may not be applicable to all available materials.

  16. Coating Characterization with the Quartz Crystal Microbalance

    Science.gov (United States)

    Sturdy, Lauren F.

    The quartz crystal microbalance is a sensitive tool that can be used to measure the mass, modulus and phase angle of films of appropriate thicknesses. It is can be applied to systems with very varied properties, from liquid to solid, and under many different conditions. In this thesis its capabilities have been used to study the properties of several different systems of relevance to the coatings, art conservation, and rubber communities, in the process of which new techniques and tools were developed to analyze data and improve QCM data collection and experimental design. Alkyd resins, which have been used in artists' paints since the twentieth century, are the subject of the first studies. Alkyds are oil-modified polyesters. These resins are of interest because of their relatively recent use in art and how little is known of the mechanical properties in the early stages of cure. The QCM was shown to be sensitive to the curing process, changes in temperature, and mass change due to exposure to water. Kinetic studies during the first days of curing showed that the curing process can be divided into three regions. The first is dominated by solvent evaporation. In the second, oxygen absorption dominates and the mechanical properties change rapidly. The final stage extends from when the film is touch dry after about a day to years and is characterized by mass loss and continued increases in the modulus. Studying the curing at different temperatures revealed that the reactions do proceed much more rapidly at higher temperatures and an overall energy of activation was calculated for the curing process. The mechanical properties of alkyd resins containing zinc oxide, a white pigment, were studied with the QCM, nanoindentation and dynamic mechanical analysis. These measurements showed increases in the modulus with the inclusion of zinc oxide, and the QCM data showed that the second region started at earlier times as the pigment concentration was increased. Linseed oil is

  17. Improvement of luminous intensity of InGaN light emitting diodes grown on hemispherical patterned sapphire

    Science.gov (United States)

    Lee, Jae-Hoon; Oh, Jeong-Tak; Park, Jin-Sub; Kim, Je-Won; Kim, Yong-Chun; Lee, Jeong-Wook; Cho, Hyung-Koun

    2006-06-01

    To improve the external quantum efficiency, high quality GaN film was grown on hemispherical patterned sapphire by controlling the V/III ratio during the initial growth stage. The luminous intensity of white flash light emitting diode (LED) grown on hemispherical patterned sapphire (HPS) was estinated to be 5.8 cd at a forward current of 150 mA, which is improved by 20% more than that of LED grown on conventional sapphire substrate. The improvement of luminous intensity was explained by considering not only an increase of the extraction efficiency via the suppressed total internal reflection at the corrugated interface but also a decrease of dislocation density.

  18. Silicon isotope composition of diagenetic quartz: A record of Precambrian weathering

    Science.gov (United States)

    Pollington, A. D.; Kozdon, R.; Valley, J. W.

    2013-12-01

    The genesis of quartz cements, which modify the porosity and permeability of many sedimentary rocks, is widely studied to determine the origin, flux, pathways and timing of water-rich fluids. Stable isotope ratios provide evidence of fluid/rock interactions. So called 'non-traditional stable isotope' ratios such as silicon may record processes such as chemical weathering, whereas aqueous fluid dominates the source of oxygen during precipitation. Silicon may be derived internally to a rock such as from pressure solution or recrystallization, or introduced by fluids. Silicon isotope ratios of diagenetic quartz reflect the source of dissolved chemical components; if δ30Si values of overgrowth quartz (OQ) and neighboring detrital quartz (DQ) are similar, the cations may be locally sourced from detrital grains. Alternatively, if the δ30Si of overgrowth quartz is significantly different than that of nearby detrital grains, then the silicon in those overgrowths is dominated by material derived from outside the formation. Here we present high-resolution in situ silicon isotope data, measured by secondary ion mass spectrometry from 10 μm spots, for the Mt Simon Sandstone, the basal Cambrian unit in the Midcontinent of North America. Silicon and oxygen isotope ratios have been measured in detrital quartz grains and quartz overgrowths from outcrops and deeply buried samples from drill core. Overgrowths from drill cores and most outcrops studied have δ30Si values close to 0‰ NBS-28, which is the same as values measured for adjacent detrital grains and δ18O values between 18 and 33‰ VSMOW, reflecting different temperatures of precipitation. However, in multiple samples from an outcrop on the Wisconsin Dome, adjacent to the Precambrian-Cambrian unconformity, quartz overgrowths have a wide range of δ30Si, with values as low as -5.4‰ and paired δ18O values as low as 18.5‰. Using the high spatial resolution afforded by SIMS analyses, we have measured isotopic

  19. Investigating the background of a 1-cm(3) quartz gas proportional counter.

    Science.gov (United States)

    Klouda, George A

    2008-01-01

    The background count rate of a 1-cm(3) quartz gas proportional counter (GPC) was investigated for measuring natural radioactivity levels of small samples. Using a new multiparameter digital counting system, spurious or afterpulses that contribute to background were identified by their pulse waveform and by a special event indicator defined by the time (low-background NaI(Tl) scintillation guard detector, the weighted mean and standard uncertainty anticoincidence counts per day (d(-1)) was 6.2+/-0.4d(-1).

  20. 110° C thermoluminescence glow peak of quartz – A brief review

    Indian Academy of Sciences (India)

    D K Koul

    2008-12-01

    The 110°C glow peak of quartz, though unstable at room temperature, has worked wonderfully in archaeology and retrospective dosimetry due to its pre-dose sensitization property. Various aspects of the peak, like its nature, defect centres involved, the impact of different stimuli and its application have been extensively studied. The main aims of this review are to (i) summarize briefly the work carried out on the various facets of this TL glow peak during the last four decades and (ii) identify the areas which need further attention in order to have a better understanding of the luminescence characteristics of this TL peak.

  1. Generation of intense femtosecond optical vortex pulses with blazed-phase grating in chirped-pulse amplification system of Ti:sapphire laser

    Science.gov (United States)

    Lin, Yu-Chieh; Nabekawa, Yasuo; Midorikawa, Katsumi

    2016-11-01

    We demonstrate the generation of an intense femtosecond optical vortex (OV) pulse by employing an OV converter set between two laser amplifiers in a chirped-pulse amplification (CPA) system of a Ti:sapphire laser. The OV converter is composed of a liquid-crystal spatial light modulator (LC-SLM) exhibiting a blazed-phase computer-generated hologram, a concave mirror, and a flat mirror in the 4f setup. Owing to the intrinsic nature of the 4f setup, the OV converter is free from chromatic and topological-charge dispersions, which are always induced in a spiral phase plate conventionally used to convert an intense Gaussian laser pulse to an OV pulse, while we can avoid damage to the LC-SLM by the irradiation of a low-energy pulse before the second amplifier. We have increased the throughput of the OV converter to 42% by systematically investigating the diffraction efficiency of the blazed-phase hologram on the LC-SLM, which relaxes the gain condition required for the second amplifier. The combination of the high-throughput OV converter and the two-stage amplification enables us to generate OV pulses with an energy of 1.63 mJ and a pulse duration of 60 fs at a wavelength of 720 nm, at which the gain of the Ti:sapphire laser is only 60% of the peak gain around 800 nm.

  2. Achieving strong doubling power by optical phase-locked Ti:sapphire laser and MOPA system

    Institute of Scientific and Technical Information of China (English)

    Yu Peng; Baike Lin; Qiang Wang; Yang Zhao; Ye Li; Jianping Cao; Zhanjun Fang; Erjun Zang

    2012-01-01

    We show two external cavity-enhanced second-harmonic generations of 922 nm with periodically poled potassium titanyl phosphate crystal,whose doubling cavities are locked separately with Hansch-Couillaud and intra-modulation methods.The outputs of second-harmonic generation reach 310 mW,54.8% of the conversion efficiency from the Ti;sapphire laser with the crystal length of 10 mm,and 208 mW,59% of the conversion efficiency from the MOPA system with the crystal length of 30 mm.It consists of heterodyning the Ti;sapphire laser and the MOPA system,and compares the phase of the beat frequency signal with the phase of a reference RF local oscillator.The resulting phase error is used as a feedback signal and fed back to the reference cavity of the Ti;sapphire laser to lock the two lasers in phase.A stable blue power of 520 mW is obtained,which supplies enough power for the cooling and trapping step of the strontium (Sr) optical lattice clock.Four stable isotopes of Sr,84Sr,86Sr,87Sr,and 88Sr,are detected by probing the laser during a strong 460.7-nm cycling transition (5s21S0-5s5p1P1).%We show two external cavity-enhanced second-harmonic generations of 922 nm with periodically poled potassium titanyl phosphate crystal, whose doubling cavities are locked separately with Hansch-Couillaud and intra-modulation methods. The outputs of second-harmonic generation reach 310 mW, 54.8% of the conversion efficiency from the Ti:sapphire laser with the crystal length of 10 mm, and 208 mW, 59% of the conversion efficiency from the MOPA system with the crystal length of 30 mm. It consists of heterodyning the Ti:sapphire laser and the MOPA system, and compares the phase of the beat frequency signal with the phase of a reference RF local oscillator. The resulting phase error is used as a feedback signal and fed back to the reference cavity of the Ti:sapphire laser to lock the two lasers in phase. A stable blue power of 520 mW is obtained, which supplies enough power for the cooling

  3. Luminescence quartz dating of lime mortars. A first research approach.

    Science.gov (United States)

    Zacharias, N; Mauz, B; Michael, C T

    2002-01-01

    Lime mortars mixed with sand are well suited for connecting structural materials, like stones and bricks, due to the mechanical properties this material exhibits. Their extensive use in architectural and decorative works during the last 4000 years motivated the introduction of the 'Luminescence clock' for age determination of mortars. The same principles as for quartz optically stimulated luminescence (OSL) dating of sediments were applied for age estimation of a mortar fragment removed from a Byzantine church monument dated by archaeological means to 1050-1100 years ago (the first half of the 10th century). The OSL from the quartz was monitored under blue light stimulation and UV detection, using a single-aliquot-regenerative-dose protocol. The quartz-OSL dating of the mortar resulted in 870 +/- 230 a. TL polymineral fine grain dating was also performed on a brick fragment which was connected to the mortar, resulting in a TL age of 1095 +/- 190 a.

  4. Ductile Regime Single Point Diamond Turning of Quartz

    Science.gov (United States)

    Ravindra, Deepak; Patten, John

    2011-01-01

    Quartz (fused silica) is one of the advanced engineered ceramic materials designed to operate in extreme environments. The mechanics of material removal in glass (Quartz) can be classified in two categories; brittle fracture and ductile plastic deformation. Good optical quality surfaces can be achieved by removing the material in a ductile manner. The strength, hardness and fracture toughness of the work piece material are the governing factors that control the extent of brittle fracture. The main goal of the subject research is to improve the surface quality of Quartz to be used as an optic device (mirrors and windows) via single point diamond turning (SPDT). Surface roughness (Ra) values of less than 50 nm without sub surface damage were obtained.

  5. New multiphase equation of state for polycrystalline quartz

    Energy Technology Data Exchange (ETDEWEB)

    Boettger, J.C.; Lyon, S.P.

    1990-10-01

    We have generated separate equations of state (EOS's) for the alpha quartz, coesite, and stishovite phases of polycrystalline quartz (SiO{sub 2}) using the computer program GRIZZLY. We also modified the program GRIZZLY to combine two single-phase EOS's for a given material into a single two-phase EOS via minimization of the Gibbs free energy. This new version of GRIZZLY has been used to generate a three-phase SESAME type EOS for polycrystalline quartz using the three EOS's mentioned above. All four of the EOS's produced for SiO{sub 2} are now available on request. 17 refs., 4 figs., 1 tab.

  6. Periodic Error Compensation for Quartz MEMS Gyroscope Drift of INS

    Institute of Scientific and Technical Information of China (English)

    Xu Jianmao; Zhang Haipeng; Sun Junzhong

    2007-01-01

    In order to improve the navigation accuracy of an inertial navigation system (INS), composed of quartz gyroscopes, the existing real-time compensation methods for periodic errors in quartz gyroscope drift and the periodic error term relationship between sampled original data and smoothed data are reviewed. On the base of the results, a new compensation method called using former period characteristics to compensate latter smoothness data (UFCL for short) method is proposed considering the INS working characteristics. This new method uses the original data without smoothing to work out an error conversion formula at the INS initial alignment time and then compensate the smoothed data errors by way of the formula at the navigation time. Both theoretical analysis and experimental results demonstrate that this method is able to cut down on computational time and raise the accuracy which makes it a better real-time compensation approach for periodic error terms of quartz micro electronic mechanical system (MEMS) gyroscope's zero drift.

  7. Properties and behavior of quartz for the silicon process

    Energy Technology Data Exchange (ETDEWEB)

    Aasly, Kurt

    2008-07-01

    This PhD-thesis is a result of the study on important properties of quartz as a raw material for the metallurgical production of ferrosilicon and silicon metal. This includes defining mechanical properties important for the size reduction experienced during transport and storage and thermo-mechanical properties of quartz that is important for how the quartz reacts to the high temperatures experienced as it is charged on the furnace. Additionally, softening properties of quartz have been briefly discussed in some of the papers. Another important goal has been to test analytical and experimental methods for investigating the various properties. The investigations of important factors for the mechanical properties of ores and industrial minerals have been carried out as a literature study. The mining operation and transport from mine to smelter has been discussed and several factors that are significant for achieving best possible mechanical properties of the quartz have been identified. The most important factors are related to production in the mine and processing plant, which should be carefully planned to minimize the amount of blast-induced damage in the rock and thus achieve the best possible mechanical strength of the raw material. The amount of fines can be minimized by controlling the handling of the raw materials during the transport and storage. It is especially important to avoid high drops, both high single drops and accumulated height of all the drops in total. Investigations of the thermo-mechanical properties of quartz have been carried out by using different experimental and characterization methods. The petrographic investigations of the raw materials by polarized light microscopy have been important. Thermo-mechanical investigations have been high-temperature microthermometry and shock heating of quartz samples in an induction furnace with subsequent investigations of the heated material. The subsequent investigation included polarized- and

  8. Dependence of quartz wettability on fluid density

    Science.gov (United States)

    Al-Yaseri, Ahmed Zarzor; Roshan, Hamid; Lebedev, Maxim; Barifcani, Ahmed; Iglauer, Stefan

    2016-04-01

    Wettability is one of the most important parameters in multiphase flow through porous rocks. However, experimental measurements or theoretical predictions are difficult and open to large uncertainty. In this work we demonstrate that gas densities (which are much simpler to determine than wettability and typically well known) correlate remarkably well with wettability. This insight can significantly improve wettability predictions, thus derisking subsurface operations (e.g., CO2 geostorage or hydrocarbon recovery), and significantly enhance fundamental understanding of natural geological processes.

  9. Single-crystal sapphire resonator at millikelvin temperatures: Observation of thermal bistability in high- Q factor whispering gallery modes

    Science.gov (United States)

    Creedon, Daniel L.; Tobar, Michael E.; Le Floch, Jean-Michel; Reshitnyk, Yarema; Duty, Timothy

    2010-09-01

    Resonance modes in single crystal sapphire (α-Al2O3) exhibit extremely high electrical and mechanical Q factors ( ≈109 at 4 K), which are important characteristics for electromechanical experiments at the quantum limit. We report the cool down of a bulk sapphire sample below superfluid liquid-helium temperature (1.6 K) to as low as 25 mK. The electromagnetic properties were characterized at microwave frequencies, and we report the observation of electromagnetically induced thermal bistability in whispering gallery modes due to the material T3 dependence on thermal conductivity and the ultralow dielectric loss tangent. We identify “magic temperatures” between 80 and 2100 mK, the lowest ever measured, at which the onset of bistability is suppressed and the frequency-temperature dependence is annulled. These phenomena at low temperatures make sapphire suitable for quantum metrology and ultrastable clock applications, including the possible realization of the quantum-limited sapphire clock.

  10. Reduction of Residual Stresses in Sapphire Cover Glass Induced by Mechanical Polishing and Laser Chamfering Through Etching

    Directory of Open Access Journals (Sweden)

    Shih-Jeh Wu

    2016-10-01

    Full Text Available Sapphire is a hard and anti-scratch material commonly used as cover glass of mobile devices such as watches and mobile phones. A mechanical polishing using diamond slurry is usually necessary to create mirror surface. Additional chamfering at the edge is sometimes needed by mechanical grinding. These processes induce residual stresses and the mechanical strength of the sapphire work piece is impaired. In this study wet etching by phosphate acid process is applied to relief the induced stress in a 1” diameter sapphire cover glass. The sapphire is polished before the edge is chamfered by a picosecond laser. Residual stresses are measured by laser curvature method at different stages of machining. The results show that the wet etching process effectively relief the stress and the laser machining does not incur serious residual stress.

  11. Chiral habit selection on nanostructured epitaxial quartz films.

    Science.gov (United States)

    Carretero-Genevrier, Adrián; Gich, Martí; Picas, Laura; Sanchez, Clément; Rodriguez-Carvajal, Juan

    2015-01-01

    Understanding the crystallization of enantiomorphically pure systems can be relevant to diverse fields such as the study of the origins of life or the purification of racemates. Here we report on polycrystalline epitaxial thin films of quartz on Si substrates displaying two distinct types of chiral habits that never coexist in the same film. We combine Atomic Force Microscopy (AFM) analysis and computer-assisted crystallographic calculations to make a detailed study of these habits of quartz. By estimating the surface energies of the observed crystallites we argue that the films are enantiomorphically pure and we briefly outline a possible mechanism to explain the habit and chiral selection in this system.

  12. Bonding energy of Sylgard on fused quartz: an experimental investigation

    Science.gov (United States)

    Liu, C.; Yeager, J. D.; Ramos, K. J.

    2015-02-01

    The bonding energy between the polymer Sylgard and fused quartz is determined experimentally using a miniature bulge test combined with three-dimensional digital image correlation (3D-DIC). Based on the experimental observation, Mindlin plate theory is used to compute the bonding energy (adhesive energy or surface energy) between the Sylgard and the fused quartz. The experimental results demonstrate that the combination of the miniature bulge test and the 3D-DIC provides a viable tool to directly measure interfacial and bonding properties.

  13. Pressure effect on the sensitivity of quartz Bourdon tube gauges.

    Science.gov (United States)

    Szaniszlo, A. J.

    1972-01-01

    The sensitivity change for a commercial fused quartz Bourdon tube precision pressure gauge, due to a change in absolute pressure level, has been analytically computed and experimentally confirmed. The computed differential pressure error is 2.5% of full scale at a 100 atm absolute pressure level. The experimental method compared the fused quartz Bourdon tube gauge digital output to the results obtained from a nitrogen gas pressure system which had a high pressure, well-type mercury manometer as the differential pressure reference.

  14. Carbothermal Reduction of Quartz in Different Gas Atmospheres

    Science.gov (United States)

    Li, Xiang; Zhang, Guangqing; Tang, Kai; Ostrovski, Oleg; Tronstad, Ragnar

    2015-01-01

    This article examines the influence of gas atmosphere on the synthesis of silicon carbide by carbothermal reduction of quartz. The quartz was crushed to Synthesis of silicon carbide in hydrogen was close to completion in 270 minutes at 1673 K (1400 °C), 140 minutes at 1773 K (1500 °C), and 70 minutes at 1873 K (1600 °C). Faster carbothermal reduction rate in hydrogen was attributed to the involvement of hydrogen in the reduction reactions by directly reducing silica and/or indirectly, by reacting with graphite to form methane as an intermediate reductant.

  15. ST Quartz Acoustic Wave Sensors with Sectional Guiding Layers

    Directory of Open Access Journals (Sweden)

    Glen McHale

    2008-07-01

    Full Text Available We report the effect of removing a section of guiding layer from the propagation paths of ST-quartz Love wave sensors; this offers the ease of fabrication of a polymer guiding layer whilst retaining the native surface of the quartz which may then be used for the attachment of a sensitizing layer. Data is presented for the rigid and viscous loading, which indicates a small reduction in mass sensitivity compared to a Love wave device. Biosensing capabilities of these discontinuous ‘sectional’ guiding layer devices are demonstrated using protein adsorption from solution.

  16. Comparison of quartz sand, anthracite, shale and biological ceramsite for adsorptive removal of phosphorus from aqueous solution.

    Science.gov (United States)

    Jiang, Cheng; Jia, Liyue; Zhang, Bo; He, Yiliang; Kirumba, George

    2014-02-01

    The choice of substrates with high phosphorus adsorption capacity is vital for sustainable phosphorus removal from waste water in constructed wetlands. In this study, four substrates were used: quartz sand, anthracite, shale and biological ceramsite. These substrate samples were characterized by Xray diffractometry and scanning electron microscopy studies for their mineral components (chemical components) and surface characteristics. The dynamic experimental results revealed the following ranking order for total phosphorus (TP) removal efficiency: anthracite > biological ceramsite > shale > quartz sand. The adsorptive removal capacities for TP using anthracite, biological ceramsite, shale and quartz sand were 85.87, 81.44, 59.65, and 55.98 mg/kg, respectively. Phosphorus desorption was also studied to analyze the substrates' adsorption efficiency in wastewater treatment as well as the substrates' ability to be reused for treatment. It was noted that the removal performance for the different forms of phosphorus was dependent on the nature of the substrate and the adsorption mechanism. A comparative analysis showed that the removal of particulate phosphorus was much easier using shale. Whereas anthracite had the highest soluble reactive phosphorus (SRP) adsorptive capacity, biological ceramsite had the highest dissolved organic phosphorus (DOP) removal capacity. Phosphorus removal by shale and biological ceramsite was mainly through chemical adsorption, precipitation or biological adsorption. On the other hand, phosphorus removal through physical adsorption (electrostatic attraction or ion exchange) was dominant in anthracite and quartz sand.

  17. Differing effects of water fugacity deformation of quartzites and milky quartz single crystals

    Science.gov (United States)

    Holyoke, C. W.; Kronenberg, A. K.

    2010-12-01

    Previous studies of quartzite deformation by dislocation creep have documented a strong dependence of mechanical properties on pressure, which has been interpreted as a relationship between strain rate and water fugacity (Kronenberg and Tullis, 1984; Kohlstedt et al., 1995; Chernak et al. 2009). However, natural milky quartz single crystals deformed by basal slip can be water-weakened over a wide range of pressure (and water fugacities), with strengths that appear to depend on total water content at a fixed water fugacity. The difference of behavior between these two is perplexing since infrared spectra collected from quartzites and milky quartz single crystals indicate that they have the same forms of intragranular water and microstructures indicate the same slip system is activated. The only difference between these materials is that quartzites include populations of grains of all orientations, separated by grain boundaries. In order to resolve this discrepancy we have performed deformation experiments on a natural quartzite (Black Hills quartzite) and natural milky quartz single crystals oriented for easy slip on the basal slip system at identical conditions (800°C, strain rate = 10-6/s) with no added water. During each experiment cores of each material, which have a fixed water content, were subjected to pressure stepping; an initial deformation step was performed at 1.5 GPa, then the sample was unloaded and one or more deformation steps were performed at lower pressures (as low as 0.6 GPa) prior to returning to 1.5 GPa for a final deformation step. The strength of quartzite increases dramatically at lower pressure and lower water fugacity, but strength decreases again returning to high pressure during the final deformation step. The strength of milky quartz single crystals increases as well, but by far less than observed for quartzites. The water fugacity exponents (m) of the quartzite and single crystals are 1.9 and 0.8, respectively, (assuming power law

  18. Study of thermoluminescence response of purple to violet amethyst quartz from Balikesir, Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Nur, N., E-mail: nnur@adiyaman.edu.tr [Adiyaman University, Engineering Faculty, Department of Electrical and Electronic Engineering, 02040 Adiyaman (Turkey); Yeğingil, Z.; Topaksu, M. [Cukurova University, Art and Sciences Faculty, Physics Department, 01330 Adana (Turkey); Kurt, K. [University of Mersin, Science and Art Faculty, Physics Department, 33343 Mersin (Turkey); Doğan, T. [Cukurova University, Vocational School of Imamoglu, Department of Technical Programs, 01700 Adana (Turkey); Sarıgül, N. [Institute of Nuclear Science, Hacettepe University, 06532 Ankara (Turkey); Yüksel, M.; Altunal, V.; Özdemir, A.; Güçkan, V. [Cukurova University, Art and Sciences Faculty, Physics Department, 01330 Adana (Turkey); Günay, I. [Cukurova University, Medicine Faculty, Biophysics Department, Adana (Turkey)

    2015-09-01

    Highlights: • We reported on dosimetric characterisation of natural amethyst quartz specimens from Turkey, using TL technique. • The thermoluminescence characterisation tests were performed under the beta radiation exposure. • The IT peaks ∼230 °C show superlinear dose response behavior (g(D) > 1) between 1 Gy and 5 kGy. The HT peaks ∼300 °C show linear behavior (g(D) = 1) at low dose levels (1 < D < 20 Gy) and superlinearity (g(D) > 1) between 20 Gy < D < 2 kGy. • Deviations were determined for recycling measurements for various dose values of 0.1, 0.5, 0.8 and 1 kGy. • Amethyst quartz has great potential to be investigated for dosimetry purpose. - Abstract: In thermoluminescence (TL) dosimetry, the phosphor amethyst quartz as a thermoluminescent, appears to be one of the materials arousing the highest interest. In this study the dosimetric characteristics of natural amethyst quartz crystals collected from Balikesir–Dursunbey (Turkey) were investigated for the purpose of determination of the general properties that phosphors should have in order to be useful for thermoluminescence dosimetry. The natural thermoluminescence was drained by annealing the powder samples at 450 °C for 1.5 h. The effects of high temperature annealing, dose response curves, glow curves after a postirradiation annealing, reusability of the samples and storage of trapped electrons in dark at room temperature were clarified through irradiating the samples with the desired exposures by {sup 90}Sr/{sup 90}Y beta particles. Isothermal annealing before and after irradiation was found to have a definite effect upon the TL glow curve of amethyst crystal powder. The same sample varied in sensitivity depending upon its previous thermal and radiation history. The peak heights of the glow peaks were examined with respect to dose response at dose levels between 1 Gy and 5 kGy. The intermediate temperature (IT) and high temperature (HT) peaks of 230 °C and 300 °C, respectively

  19. Evaluation of the Quality of Sapphire Using X-Ray Rocking Curves and Double-Crystal X-Ray Topography

    Science.gov (United States)

    1994-05-01

    hard, high-strength, chemically resistant optical windows; and sub- srates for the growth of epitaxial films. The quality of a sapphire crystal can... crystal diffractometer. Single- crystal sapphire may be grown by a variety of different methods, of which the more common are Verneuil (flame fusion...Linear features (L), which may represent slight variations in lattice parameter along the crystal growth front, or dislocation networks, ad small

  20. Formation of silicon nanocrystals in sapphire by ion implantation and the origin of visible photoluminescence

    Science.gov (United States)

    Yerci, S.; Serincan, U.; Dogan, I.; Tokay, S.; Genisel, M.; Aydinli, A.; Turan, R.

    2006-10-01

    Silicon nanocrystals, average sizes ranging between 3 and 7nm, were formed in sapphire matrix by ion implantation and subsequent annealing. Evolution of the nanocrystals was detected by Raman spectroscopy and x-ray diffraction (XRD). Raman spectra display that clusters in the matrix start to form nanocrystalline structures at annealing temperatures as low as 800°C in samples with high dose Si implantation. The onset temperature of crystallization increases with decreasing dose. Raman spectroscopy and XRD reveal gradual transformation of Si clusters into crystalline form. Visible photoluminescence band appears following implantation and its intensity increases with subsequent annealing process. While the center of the peak does not shift, the intensity of the peak decreases with increasing dose. The origin of the observed photoluminescence is discussed in terms of radiation induced defects in the sapphire matrix.

  1. Process for the Φ130 sapphire window element with long distance and high resolution

    Science.gov (United States)

    Xu, Zengqi; Su, Ying; Lei, Jianli; Guo, Rui; Zhang, Feng; Guo, Xinlong; Liu, Xuanmin; Sun, Taohui

    2016-10-01

    With the process test for the choice of materials, the test materials and the molds, the abrasives, the temperature and the different machining process monitoring parameters of the polishing machine, the process method and the quality control technology were figured out for the Φ130 sapphire window element with long distance and high resolution (hereinafter referred to as window element), meantime, the optimum process condition was determined to machine the element. The results were that the high resolution imaging window was processed with the surface roughness Ra of 0.639nm, the transmission distortion of λ/10 (λ=632.8nm), the parallel error of 5″, the resolution of 1.47″ and the focal length of 5 km, which can satisfy the imaging requirements better for the military photoelectric device for sapphire window with long distance and high resolution.

  2. Growth and Characterization of InN Thin Films on Sapphire by MOCVD

    Institute of Scientific and Technical Information of China (English)

    XIE Zi-Li; ZHANG Rong; XIU Xiang-Qian; LIU Bin; LI Liang; HAN Ping; GU Shu-Lin; SHI Yi; ZHENG You-Dou

    2007-01-01

    Indium nitride thin films are grown on sapphire substrates by metal-organic chemical vapour deposition(MOCVD).By employing three-step layer buffers,the mirror-like layers on two-inch sapphire wafers have been obtained.The structural,optical and electrical characteristics of InN are investigated by x-ray diffraction,scanning electron microscopy,atomic force microscopy,photoluminescence and infrared optical absorpton.The photoluminescence and the absorption studies of the materials reveal a marked energy bandgap structure around 0.70 eV at room temperature.The room-temperature Hall mobility and carrier concentration of the film are typically 939 cm2/Vs,and 3.9×1018cm-3,respectively.

  3. Degradation of picosecond temporal contrast of Ti:sapphire lasers with coherent pedestals.

    Science.gov (United States)

    Khodakovskiy, Nikita; Kalashnikov, Mikhail; Gontier, Emilien; Falcoz, Franck; Paul, Pierre-Mary

    2016-10-01

    Recompressed pulses from Ti:sapphire chirped-pulse lasers are accompanied by a slowly decaying post-pulse pedestal that is coherent with the main pulse. The pedestal typically consists of numerous pulses with temporal separation in the picosecond range. The source of this artifact lies in the Ti:sapphire active medium itself, both in the Kerr-lens mode-locked oscillator and in subsequent amplifiers. In the presence of substantial self-phase modulation, after recompression the post-pedestal generates a mirror-symmetric pre-pulse pedestal. This pedestal severely degrades the leading edge of the output pulse. This degradation is far more limiting than the original post-pedestal and severely lowers the achievable temporal contrast.

  4. Achieving λ/10 resolution CW STED nanoscopy with a Ti:Sapphire oscillator.

    Directory of Open Access Journals (Sweden)

    Yujia Liu

    Full Text Available In this report, a Ti:Sapphire oscillator was utilized to realize synchronization-free stimulated emission depletion (STED microscopy. With pump power of 4.6 W and sample irradiance of 310 mW, we achieved super-resolution as high as 71 nm. With synchronization-free STED, we imaged 200 nm nanospheres as well as all three cytoskeletal elements (microtubules, intermediate filaments, and actin filaments, clearly demonstrating the resolving power of synchronization-free STED over conventional diffraction limited imaging. It also allowed us to discover that, Dylight 650, exhibits improved performance over ATTO647N, a fluorophore frequently used in STED. Furthermore, we applied synchronization-free STED to image fluorescently-labeled intracellular viral RNA granules, which otherwise cannot be differentiated by confocal microscopy. Thanks to the widely available Ti:Sapphire oscillators in multiphoton imaging system, this work suggests easier access to setup super-resolution microscope via the synchronization-free STED.

  5. Characterization of superconducting magnesium-diboride films on glassy carbon and sapphire substrates

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, E.; Zavala, E. P. [Instituto de Fisica, UNAM, Apartado Postal 20-364, 01000 Mexico D. F. (Mexico); Rocha, M. F. [Escuela Superior de Ingenieria Mecanica y Electrica, IPN, Mexico D. F. (Mexico); Jergel, M.; Falcony, C. [Departamento de Fisica, CINVESTAV-IPN, Apartado postal 14-740, 07000 Mexico D. F. (Mexico)

    2008-02-15

    IBA methods were applied to measure elemental depth profiles of precursors and superconducting MgB{sub 2} thin films deposited on glassy carbon (Good Fellows) and sapphire (Al{sub 2}O{sub 3}) substrates. For each type of substrates we obtained a pair of samples i.e. one amorphous precursor and one superconducting film which were then characterized. A 3{sup H}e{sup +} beam was used to bombard both, precursors and superconducting films in order to obtain the samples elemental composition profiles. The zero resistance T{sub co} and the middle of transition T{sub cm} values were 26.0 K and 29.7 K for the MgB{sub 2} film deposited on glassy carbon substrate. In the case of sapphire substrate the T{sub co} and T{sub cm} values were 25.0 K and 27.9 K, respectively. (Author)

  6. Nearly octave-spanning frequency comb generation in AlN-on-sapphire microresonators

    CERN Document Server

    Liu, Xianwen; Xiong, Bing; Wang, Lai; Wang, Jian; Han, Yanjun; Hao, Zhibiao; Li, Hongtao; Luo, Yi; Yan, Jianchang; Wei, Tongbo; Zhang, Yun; Wang, Junxi

    2016-01-01

    We report a nearly octave-spanning optical frequency comb generation with a coverage of $\\sim$1000 nm in continuous-wave pumped aluminum nitride (AlN)-on-sapphire microring resonators. Thanks to optimized device design and fabrication process, high-quality-factor AlN microrings with high cavity finesse and low insertion loss are demonstrated. By tailoring the cavity dimension, a broadband anomalous dispersion is secured to facilitate the frequency comb generation. Blue-shifted dispersive wave emission as well as stimulated Raman scattering is observed, which helps extend the comb spectrum coverage. Our work suggests that AlN-on-sapphire can be an appealing platform for integrated nonlinear optics.

  7. Structural, transport and microwave properties of 123/sapphire films: Thickness effect

    Energy Technology Data Exchange (ETDEWEB)

    Predtechensky, MR.; Smal, A.N.; Varlamov, Y.D. [Institute of Thermophysics, Novosibirsk (Russian Federation)] [and others

    1994-12-31

    The effect of thickness and growth conditions on the structure and microwave properties has been investigated for the 123/sapphire films. It has been shown that in the conditions of epitaxial growth and Al atoms do not diffuse from substrate into the film and the films with thickness up to 100nm exhibit the excellent DC properties. The increase of thickness of GdBaCuO films causes the formation of extended line-mesh defects and the increase of the surface resistance (R{sub S}). The low value of surface resistance R{sub S}(75GHz,77K)=20 mOhm has been obtained for the two layer YBaCuO/CdBaCuO/sapphire films.

  8. Evaluation of heat extraction through sapphire fibers for the GW observatory KAGRA

    OpenAIRE

    Khalaidovski, Alexander; Hofmann, Gerd; CHEN, DAN; Komma, Julius; Schwarz, Christian; Tokoku, Chihiro; Kimura, Nobuhiro; Suzuki, Toshikazu; Scheie, Allen O.; Majorana, Ettore; Nawrodt, Ronny; Yamamoto, Kazuhiro

    2014-01-01

    Currently, the Japanese gravitational wave laser interferometer KAGRA is under construction in the Kamioka mine. As one main feature, it will employ sapphire mirrors operated at a temperature of 20K to reduce the impact from thermal noise. To reduce seismic noise, the mirrors will also be suspended from multi-stage pendulums. Thus the heat load deposited in the mirrors by absorption of the circulating laser light as well as heat load from thermal radiation will need to be extracted through th...

  9. High energy terahertz pulses from organic crystals: DAST and DSTMS pumped at Ti:sapphire wavelength

    CERN Document Server

    Monoszlai, B; Jazbinsek, M; Hauri, C P

    2013-01-01

    High energy terahertz pulses are produced by optical rectification (OR) in organic crystals DAST and DSTMS by a Ti:sapphire amplifier system centered at 0.8 microns. The simple scheme provides broadband spectra between 1 and 5 THz, when pumped by collimated 60 fs near-infrared pump pulse and it is scalable in energy. Fluence-dependent conversion efficiency and damage threshold are reported as well as optimized OR at visible wavelength.

  10. Silicon-on-Sapphire Waveguides: Mode-converting Couplers and Four-wave Mixing

    Science.gov (United States)

    2014-09-01

    width of the waveguides was between 1600 and 1900 nm . Figure 1 shows gain bands for a waveguide with 500- nm height and 1700 - nm width, demonstrating...1. Calculated conversion efficiency of four-wave mixing in 1700 - nm wide silicon-on-sapphire waveguide. Color bar indicates conversion efficiency in...dominance. Previous investigations show that this spectral range is of interest for applications that include free-space communications, laser radar

  11. ZnO Nanostructures Grown on AlN/Sapphire Substrates by MOCVD

    Institute of Scientific and Technical Information of China (English)

    WEI Hong-Yuan; HU Wei-Guo; ZHANG Pan-Feng; LIU Xiang-Lin; ZHU Qin-Sheng; WANG Zhan-Guo

    2007-01-01

    ZnO nanorods and nanotubes are successful synthesized on AlN/sapphire substrates by metal-organic chemical vapour deposition (MOCVD). The different morphology and structure properties of ZnO nanorods and nanotubes are found to be affected by the A1N under-layer. The photoluminescence spectra show the optical properties of the ZnO nanorods and nanotubes, in which a blueshift of UV emission is observed and is attributed to the surface effect.

  12. Femtosecond Ti:sapphire cryogenic amplifier with high gain and MHz repetition rate.

    Science.gov (United States)

    Dantan, Aurélien; Laurat, Julien; Ourjoumtsev, Alexei; Tualle-Brouri, Rosa; Grangier, Philippe

    2007-07-09

    We demonstrate high gain amplification of 160-femtosecond pulses in a compact double-pass cryogenic Ti:sapphire amplifier. The setup involves a negative GVD mirrors recompression stage, and operates with a repetition rate between 0.2 and 4 MHz with a continuous pump laser. Amplification factors as high as 17 and 320 nJ Fourier-limited pulses are obtained at a 800 kHz repetition rate.

  13. Direct pumping of ultrashort Ti:sapphire lasers by a frequency doubled diode laser

    DEFF Research Database (Denmark)

    Müller, André; Jensen, Ole Bjarlin; Unterhuber, Angelika

    2011-01-01

    electro-optical efficiency of the diode laser. Autocorrelation measurements show that pulse widths of less than 20 fs can be expected with an average power of 52 mW when using our laser. These results indicate the high potential of direct diode laser pumped Ti: sapphire lasers to be used in applications...... like retinal optical coherence tomography (OCT) or pumping of photonic crystal fibers for CARS (coherent anti-stokes Raman spectroscopy) microscopy....

  14. A microwave exciter for Cs frequency standards based on a sapphire-loaded cavity oscillator.

    Science.gov (United States)

    Koga, Y; McNeilage, C; Searls, J H; Ohshima, S

    2001-01-01

    A low noise and highly stable microwave exciter system has been built for Cs atomic frequency standards using a tunable sapphire-loaded cavity oscillator (SLCO), which works at room temperature. This paper discusses the successful implementation of a control system for locking the SLCO to a long-term reference signal and reports an upper limit of the achieved frequency tracking error 6 x 10(-15) at tau = 1 s.

  15. High Power Widely Tunable Narrow Linewidth All-Solid-State Pulsed Titanium-Doped Sapphire Laser

    Institute of Scientific and Technical Information of China (English)

    DING Xin; LI Xue; SHENG Quan; SHI Chun-Peng; YIN Su-Jia; LI Bin; YU Xuan-Yi; WEN Wu-Qi; YAO Jian-Quan

    2011-01-01

    We report a widely tunable, narrow linewidth, pulsed Ti:sapphire laser pumped by an all-solid-state Q-switched intra-cavity frequency-doubled Nd:YAG laser. By using four dense Bint glass prisms as intra-cavity dispersive elements, the output wavelength can be continuously tuned over 675-970 nm and the spectral linewidth is shortened to 0.5nm. The maximum output power of 6.65 W at 780 nm is obtained under 23.4 Wpump power with repetition rate of 5.5 kHz; corresponding to an conversion efficiency of 28.4%. Due to the gain-switching characteristics of the Ti:sapphire laser, the output pulse duration is as short as 17.6ns.%@@ We report a widely tunable,narrow linewidth,pulsed Th:sapphire laser pumped by an all-solid-state Q-switched intra-cavity frequency-doubled Nd:YAG laser.By using four dense flint glass prisms as intra-cavity dispersive elements,the output wavelength can be continuously tuned over 675-970nm and the spectral linewidth is shortened to 0.5 nm.The maximum output power of 6.65 W at 780 run is obtained under 23.4 W pump power with repetition rate of 5.5 kHz,corresponding to an conversion efficiency of 28.4%.Due to the gain-switching characteristics of the Ti:sapphire laser,the output pulse duration is as short as 17.6ns.

  16. Amplified spontaneous emission and its restraint in a terawatt Ti:sapphire amplifier

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Amplified spontaneous emission (ASE) and its restraint in a femtosecond Ti: sapphire chirped_pulse amplifier were investigated. The noises arising from ASE were effectively filtered out in the spatial, temporal and spectral domain. Pulses as short as 38 fs were amplified to peak power of 1.4 TW. The power ratio between the amplified femtosecond pulse and the ASE was higher than 106:1.

  17. Molecular beam epitaxy of InN dots on nitrided sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Romanyuk, Yaroslav E.; Dengel, Radu-Gabriel; Stebounova, LarissaV.; Leone, Stephen R.

    2007-04-20

    A series of self-assembled InN dots are grown by radio frequency (RF) plasma-assisted molecular beam epitaxy (MBE) directly on nitrided sapphire. Initial nitridation of the sapphire substrates at 900 C results in the formation of a rough AlN surface layer, which acts as a very thin buffer layer and facilitates the nucleation of the InN dots according to the Stranski-Krastanow growth mode, with a wetting layer of {approx}0.9 nm. Atomic force microscopy (AFM) reveals that well-confined InN nanoislands with the greatest height/width at half-height ratio of 0.64 can be grown at 460 C. Lower substrate temperatures result in a reduced aspect ratio due to a lower diffusion rate of the In adatoms, whereas the thermal decomposition of InN truncates the growth at T>500 C. The densities of separated dots vary between 1.0 x 10{sup 10} cm{sup -2} and 2.5 x 10{sup 10} cm{sup -2} depending on the growth time. Optical response of the InN dots under laser excitation is studied with apertureless near-field scanning optical microscopy and photoluminescence spectroscopy, although no photoluminescence is observed from these samples. In view of the desirable implementation of InN nanostructures into photonic devices, the results indicate that nitrided sapphire is a suitable substrate for growing self-assembled InN nanodots.

  18. Milli-electronvolt monochromatization of hard X-rays with a sapphire backscattering monochromator

    Science.gov (United States)

    Sergueev, I.; Wille, H.-C.; Hermann, R. P.; Bessas, D.; Shvyd’ko, Yu. V.; Zając, M.; Rüffer, R.

    2011-01-01

    A sapphire backscattering monochromator with 1.1 (1) meV bandwidth for hard X-rays (20–40 keV) is reported. The optical quality of several sapphire crystals has been studied and the best crystal was chosen to work as the monochromator. The small energy bandwidth has been obtained by decreasing the crystal volume impinged upon by the beam and by choosing the crystal part with the best quality. The monochromator was tested at the energies of the nuclear resonances of 121Sb at 37.13 keV, 125Te at 35.49 keV, 119Sn at 23.88 keV, 149Sm at 22.50 keV and 151Eu at 21.54 keV. For each energy, specific reflections with sapphire temperatures in the 150–300 K region were chosen. Applications to nuclear inelastic scattering with these isotopes are demonstrated. PMID:21862862

  19. Growth of p-CdTe thin films on n-GaN/sapphire

    Science.gov (United States)

    Jung, Younghun; Chun, Seunju; Kim, Donghwan; Kim, Jihyun

    2011-07-01

    CdTe thin film was successfully grown on GaN/Sapphire substrate using a close spaced sublimation (CSS) system for the applications in solar cells. CdTe thin film was characterized by SEM, micro-Raman spectroscopy, and X-ray diffraction. The growth rate was 1 μm/min. In addition, we confirmed that CdCl 2 treatment beneficially influenced the structure and composition of the CdTe thin films. CdCl 2 treatment which has been known that it improved the efficiency of the CdS/CdTe solar cells, produced similar positive effects such as increasing the CdTe grain size and reducing the number of pin-holes. The growth of the CdTe thin film by CSS method produced nominal effects on biaxial strain and carrier concentrations in the GaN/Sapphire substrate. The CdTe thin film grown on the GaN/Sapphire substrate holds great promise for use in solar cell applications due to its several advantages.

  20. Molecular beam epitaxy of InN dots on nitrided sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Romanyuk, Yaroslav E.; Dengel, Radu-Gabriel; Stebounova, LarissaV.; Leone, Stephen R.

    2007-04-20

    A series of self-assembled InN dots are grown by radio frequency (RF) plasma-assisted molecular beam epitaxy (MBE) directly on nitrided sapphire. Initial nitridation of the sapphire substrates at 900 C results in the formation of a rough AlN surface layer, which acts as a very thin buffer layer and facilitates the nucleation of the InN dots according to the Stranski-Krastanow growth mode, with a wetting layer of {approx}0.9 nm. Atomic force microscopy (AFM) reveals that well-confined InN nanoislands with the greatest height/width at half-height ratio of 0.64 can be grown at 460 C. Lower substrate temperatures result in a reduced aspect ratio due to a lower diffusion rate of the In adatoms, whereas the thermal decomposition of InN truncates the growth at T>500 C. The densities of separated dots vary between 1.0 x 10{sup 10} cm{sup -2} and 2.5 x 10{sup 10} cm{sup -2} depending on the growth time. Optical response of the InN dots under laser excitation is studied with apertureless near-field scanning optical microscopy and photoluminescence spectroscopy, although no photoluminescence is observed from these samples. In view of the desirable implementation of InN nanostructures into photonic devices, the results indicate that nitrided sapphire is a suitable substrate for growing self-assembled InN nanodots.

  1. Influence of TMAl preflow on AlN epitaxy on sapphire

    KAUST Repository

    Sun, Haiding

    2017-05-12

    The trimethylaluminum (TMAl) preflow process has been widely applied on sapphire substrates prior to growing Al-polar AlN films by metalorganic chemical vapor deposition. However, it has been unclear how the TMAl preflow process really works. In this letter, we reported on carbon\\'s significance in the polarity and growth mode of AlN films due to the TMAl preflow. Without the preflow, no trace of carbon was found at the AlN/sapphire interface and the films possessed mixed Al- and N-polarity. With the 5 s preflow, carbon started to precipitate due to the decomposition of TMAl, forming scattered carbon-rich clusters which were graphitic carbon. It was discovered that the carbon attracted surrounding oxygen impurity atoms and consequently suppressed the formation of AlxOyNz and thus N-polarity. With the 40 s preflow, the significant presence of carbon clusters at the AlN/sapphire interface was observed. While still attracting oxygen and preventing the N-polarity, the carbon clusters served as randomly distributed masks to further induce a 3D growth mode for the AlN growth. The corresponding epitaxial growth mode change is discussed.

  2. Preparation, properties and application of sapphire single-crystal fibers grown by the EFG method

    Directory of Open Access Journals (Sweden)

    Kubát J.

    2013-05-01

    Full Text Available Sapphire – the single crystal of aluminum oxide (Al2O3 – is one of the most important artificially produced materials. The sapphire fibres studied were grown in Crytur using the “edge-defined film-fed growth” (EFG technique. Their unique physical and chemical properties can be employed in various applications. Due to their high refractive index and a broad transmission band spanning the ultraviolet, visible and infrared bands, sapphire fibres are perfect waveguides in harsh environments. The current major applications are Er:YAG laser beam delivery and pyrometric and spectrometric measurements in furnaces, combustion engines, etc. In this paper we summarize an adjustment of the EFG method to grow thin filaments by giving possible molybdenum die designs. We investigated the fibres using an optical microscope and measured their transmission of an Er:YAG laser beam (2.94 μm. The attenuation of the tested samples is approximately 0.1 dB/cm.

  3. Layered MoS{sub 2} grown on c-sapphire by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Yen-Teng; Ma, Chun-Hao; Luong, Tien-Tung; Wei, Lin-Lung; Yen, Tzu-Chun; Chu, Yung-Ching; Tu, Yung-Yi [Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu (China); Hsu, Wei-Ting; Chang, Wen-Hao [Department of Electrophysics, National Chiao Tung University, Hsinchu (China); Pande, Krishna Prasad [Department of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu (China); Chang, Edward Yi [Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu (China); Department of Electronics Engineering, National Chiao Tung University, Hsinchu (China)

    2015-03-01

    Layered growth of molybdenum disulphide (MoS{sub 2}) was successfully achieved by pulsed laser deposition (PLD) method on c -plane sapphire substrate. Growth of monolayer to a few monolayer MoS{sub 2}, dependent on the pulsed number of excimer laser in PLD is demonstrated, indicating the promising controllability of layer growth. Among the samples with various pulse number deposition, the frequency difference (A{sub 1g}-E{sup 1}{sub 2g}) in Raman analysis of the 70 pulse sample is estimated as 20.11 cm{sup -1}, suggesting a monolayer MoS{sub 2} was obtained. Two-dimensional (2D) layer growth of MoS{sub 2} is confirmed by the streaky reflection high energy electron diffraction (RHEED) patterns during growth and the cross-sectional view of transmission electron microscopy (TEM). The in-plane relationship, (0006) sapphire//(0002)MoS{sub 2} and [2 anti 1 anti 10] sapphire//[0 anti 1 anti 10]MoS{sub 2} is determined. The results imply that PLD is suitable for layered MoS{sub 2} growth. Additionally, the oxide states of Mo 3d core level spectra of PLD grown MoS{sub 2}, analysed by X-ray photoelectron spectroscopy (XPS), can be effectively reduced by adopting a post sulfurization process. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Defect formation and recrystallization in the silicon on sapphire films under Si{sup +} irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shemukhin, A.A., E-mail: shemuhin@gmail.com [Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow (Russian Federation); Nazarov, A.V.; Balakshin, Yu. V. [Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow (Russian Federation); Chernysh, V.S. [Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow (Russian Federation); Faculty of Physics, Lomonosov Moscow State University, Moscow (Russian Federation)

    2015-07-01

    Silicon-on-sapphire (SOS) is one of the most promising silicon-on-insulator (SOI) technologies. SOS structures are widely used in microelectronics, but to meet modern requirements the silicon layer should be 100 nm thick or less. The problem is in amount of damage in the interface layer, which decreases the quality of the produced devices. In order to improve the crystalline structure quality SOS samples with 300 nm silicon layers were implanted with Si{sup +} ions with energies in the range from 180 up to 230 keV with fluences in the range from 10{sup 14} up to 5 × 10{sup 15} cm{sup −2} at 0 °C. The crystalline structure of the samples was studied with RBS and the interface layer was studied with SIMS after subsequent annealing. It has been found out that to obtain silicon films with high lattice quality it is necessary to damage the sapphire lattice near the silicon–sapphire interface. Complete destruction of the strongly defected area and subsequent recrystallization depends on the energy of implanted ions and the substrate temperature. No significant mixing in the interface layer was observed with the SIMS.

  5. Graphene films grown on sapphire substrates via solid source molecular beam epitaxy

    Institute of Scientific and Technical Information of China (English)

    Tang Jun; Kang Chao-Yang; Li Li-Min; Liu Zhong-Liang; Yan Wen-Sheng; Wei Shi-Qiang; Xu Peng-Shou

    2012-01-01

    A method for growing graphene on a sapphire substrate by depositing an SiC buffer layer and then annealing at high temperature in solid source molecular beam epitaxy(SSMBE)equipment was presented.The structural and electronic properties of the samples were characterized by reflection high energy diffraction(RHEED),X-ray diffractionφ scans,Raman spectroscopy,and near edge X-ray absorption fine structure(NEXAFS)spectroscopy.The results of the RHEED and φ scan,as well as the Raman spectra,showed that an epitaxial hexagonal α-SiC layer was grown on the sapphire substrate.The results of the Raman and NEXAFS spectra revealed that the graphene films with the AB Bernal stacking structure were formed on the sapphire substrate after annealing.The layer number of the graphene was between four and five,and the thickness of the unreacted SiC layer was about 1-1.5 mm.

  6. Precision Measurement of a low-loss Cylindrical Dumbbell-Shaped Sapphire Mechanical Oscillator using Radiation Pressure

    CERN Document Server

    Bourhill, Jeremy; Tbar, Michael

    2015-01-01

    We present first results from a number of experiments conducted on a 0.53 kg cylindrical dumbbell-shaped sapphire crystal. This is the first reported optomechanical experiment of this nature utilising a novel modification to the typical cylindrical architecture. Mechanical motion of the crystal structure alters the dimensions of the crystal, and the induced strain changes the permittivity. These two effects result in parametric frequency modulation of resonant microwave whispering gallery modes that are simultaneously excited within the crystal. A novel low-noise microwave readout system is implemented allowing extremely low noise measurements of this frequency modulation near our modes of interest, having a phase noise floor of -165 dBc/Hz at 100 kHz. Fine-tuning of the crystal's suspension has allowed for the optimisation of mechanical quality factors in preparation for cryogenic experiments, with a value of Q=8 x 10^7 achieved at 127 kHz. This results in a Q x f product of 10^13, equivalent to the best mea...

  7. Quartz-like Crystals Found in Planetary Disks

    Science.gov (United States)

    2008-01-01

    NASA's Spitzer Space Telescope has, for the first time, detected tiny quartz-like crystals sprinkled in young planetary systems. The crystals, which are types of silica minerals called cristobalite and tridymite, can be seen close-up in the black-and-white insets (cristobalite is on the left, and tridymite on the right). The main picture is an artist's concept of a young star and its swirling disk of planet-forming materials. Cristobalite and tridymite are thought to be two of many planet ingredients. On Earth, they are normally found as tiny crystals in volcanic lava flows and meteorites from space. These minerals are both related to quartz. For example, if you were to heat the familiar quartz crystals often sold as mystical tokens, the quartz would transform into cristobalite and tridymite. Because cristobalite and tridymite require rapid heating and cooling to form, astronomers say they were most likely generated by shock waves traveling through the planetary disks. The insets are Scanning Electron Microscope pictures courtesy of George Rossman of the California Institute of Technology, Pasadena, Calif.

  8. Application of quartz crystal microbalance technology in tribological investigation

    Science.gov (United States)

    The last fifteen years have seen considerable growth in the application of quartz crystal microbalance (QCM) to explore the tribological characteristics of materials. This article reviews some of the advances made in characterizing frictional properties of materials using the QCM, especially with di...

  9. Absorbed dose evaluations in retrospective dosimetry: Methodological developments using quartz

    DEFF Research Database (Denmark)

    Bailiff, I.K.; Bøtter-Jensen, L.; Correcher, V.

    2000-01-01

    Dose evaluation procedures based on luminescence techniques were applied to 50 quartz samples extracted from bricks that had been obtained from populated or partly populated settlements in Russia and Ukraine downwind of the Chernobyl NPP. Determinations of accrued dose in the range similar to 30...

  10. A new equation of state for α-quartz

    Science.gov (United States)

    Magyar, Rudolph; Carpenter, John

    2015-06-01

    Quartz (SiO2) is often used as an optically transparent window for visar signals in shock experiments and is itself an active component of the experiments. Therefore, the shock response of quartz is an important input that must be known to high fidelity for precise measurement of other materials. We describe on-going work to develop a wide-range equation of state table that includes multiple phases and incorporates the latest high quality experimental and density functional theory (DFT) calculations. The emphasis in this work is the proper description of α-quartz along its principal Hugoniot through Stishovite and liquid phases. While molecular dissociation occurs at high pressures and temperatures, we find that an additional dissociation model is unnecessary. Although SiO2 possesses a number of solid phases, we restrict our focus to α-quartz and Stishovite as these two provide the density change along the Hugoniot path. We compare the model to recently measured data on Sandia's Z-machine. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE.

  11. Equivalent dose determination using a quartz isothermal TL signal

    DEFF Research Database (Denmark)

    Vandenberghe, D.A.G.; Jain, Mayank; Murray, A.S.

    2009-01-01

    We report on further developments in the use of an isothermal thermoluminescence (ITL) signal for determining the equivalent dose (De) in unheated sedimentary quartz. In order to minimise sensitivity change during the first measurement, the ITL signal is measured at 270 °C following a preheat...

  12. Characterization of silica quartz as raw material in photovoltaic applications

    Science.gov (United States)

    Boussaa, S. Anas; Kheloufi, A.; Zaourar, N. Boutarek; Kefaifi, A.; Kerkar, F.

    2016-07-01

    Raw materials are essential for the functioning of modern societies, and access to these raw materials is vital to the world economy. Sustainable development, both globally level, raises important new challenges associated with access and efficient use of raw materials. High purity quartz, is consider as a critical raw material and it is a rare commodity that only forms under geological conditions where a narrow set of chemical and physical parameters is fulfilled. When identified and following special beneficiation techniques, high purity quartz obtains very attractive prices and is applied in high technology sectors that currently are under rapid expansion such as photovoltaic solar cells, silicon metal - oxide wafers in the semiconductor industry and long distance optical fibers that are used in communication networks. Crystalline silicon remains the principal material for photovoltaic technology. Metallurgical silicon is produced industrially by the reduction of silica with carbon in an electric arc furnace at temperatures higher than 2000 °C in the hottest parts, by a reaction that can be written ideally as: SiO2 + 2C = Si + 2CO. The aim of this study has been to test experimental methods for investigating the various physical and chemical proprieties of Hoggar quartz with different techniques: X Ray Fluorescence, infra-red spectroscopy, Scanning Electron Microscopy, Optic Microscopy, Carbon Analyzer and Vickers Hardness. The results show finally that the quartz has got good result in purity but need enrichment for the photovoltaic application.

  13. Characterization of silica quartz as raw material in photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Boussaa, S. Anas, E-mail: sabiha.anas@gmail.com; Kheloufi, A.; Kefaifi, A.; Kerkar, F. [Division croissance cristalline et procédés métallurgiques CCPM Centre de recherche en technologie des semi-conducteurs pour l’énergétique (C.R.T.S.E) 02 Bd Frantz Fanon BP. 140 Alger 7 merveilles, Alger 16200 (Algeria); Zaourar, N. Boutarek [Laboratoire des technologies des matériaux, USTHB, B.P. 32 El Alia, Bab Ezzouar, Alger, Algérie 16111 (Algeria)

    2016-07-25

    Raw materials are essential for the functioning of modern societies, and access to these raw materials is vital to the world economy. Sustainable development, both globally level, raises important new challenges associated with access and efficient use of raw materials. High purity quartz, is consider as a critical raw material and it is a rare commodity that only forms under geological conditions where a narrow set of chemical and physical parameters is fulfilled. When identified and following special beneficiation techniques, high purity quartz obtains very attractive prices and is applied in high technology sectors that currently are under rapid expansion such as photovoltaic solar cells, silicon metal - oxide wafers in the semiconductor industry and long distance optical fibers that are used in communication networks. Crystalline silicon remains the principal material for photovoltaic technology. Metallurgical silicon is produced industrially by the reduction of silica with carbon in an electric arc furnace at temperatures higher than 2000 °C in the hottest parts, by a reaction that can be written ideally as: SiO{sub 2} + 2C = Si + 2CO. The aim of this study has been to test experimental methods for investigating the various physical and chemical proprieties of Hoggar quartz with different techniques: X Ray Fluorescence, infra-red spectroscopy, Scanning Electron Microscopy, Optic Microscopy, Carbon Analyzer and Vickers Hardness. The results show finally that the quartz has got good result in purity but need enrichment for the photovoltaic application.

  14. Atomistic Molecular Dynamics Simulations of Shock Compressed Quartz

    CERN Document Server

    Farrow, Matthew R

    2011-01-01

    Atomistic non-equilibrium molecular dynamics (NEMD) simulations of shock wave compression of quartz have been performed using the so-called BKS semi-empirical potential of van Beest, Kramer and van Santen to construct the Hugoniot of quartz. Our scheme mimics the real world experimental set up by using a flyer-plate impactor to initiate the shock wave and is the first shock wave simulation that uses a geom- etry optimised system of a polar slab in a 3-dimensional system employing periodic boundary conditions. Our scheme also includes the relaxation of the surface dipole in the polar quartz slab which is an essential pre-requisite to a stable simulation. The original BKS potential is unsuited to shock wave calculations and so we propose a simple modification. With this modification, we find that our calculated Hugoniot is in good agreement with experimental shock wave data up to 25 GPa, but significantly diverges beyond this point. We conclude that our modified BKS potential is suitable for quartz under repres...

  15. PARALLEL FINITE ELEMENT ANALYSIS OF HIGH FREQUENCY VIBRATIONS OF QUARTZ CRYSTAL RESONATORS ON LINUX CLUSTER

    Institute of Scientific and Technical Information of China (English)

    Ji Wang; Yu Wang; Wenke Hu; Wenhua Zhao; Jianke Du; Dejin Huang

    2008-01-01

    Quartz crystal resonators are typical piezoelectric acoustic wave devices for frequency control applications with mechanical vibration frequency at the radio-frequency (RF) range. Precise analyses of the vibration and deformation are generally required in the resonator design and improvement process. The considerations include the presence of electrodes, mountings, bias fields such as temperature, initial stresses, and acceleration. Naturally, the finite element method is the only effective tool for such a coupled problem with multi-physics nature. The main challenge is the extremely large size of resulted linear equations. For this reason, we have been employing the Mindlin plate equations to reduce the computational difficulty. In addition, we have to utilize the parallel computing techniques on Linux clusters, which are widely available for academic and industrial applications nowadays, to improve the computing efficiency. The general principle of our research is to use open source software components and public domain technology to reduce cost for developers and users on a Linux cluster. We start with a mesh generator specifically for quartz crystal resonators of rectangular and circular types, and the Mindlin plate equations are implemented for the finite element analysis. Computing techniques like parallel processing, sparse matrix handling, and the latest eigenvalue extraction package are integrated into the program. It is clear from our computation that the combination of these algorithms and methods on a cluster can meet the memory requirement and reduce computing time significantly.

  16. Study on Inclusions in Natural and Synthetic Gems

    Institute of Scientific and Technical Information of China (English)

    李兆麟

    2001-01-01

    The characteristics of inclusions in natural and synthetic gems are distinct owing to their different forming mechanisms and can be utilized to distinguish gems from different locali ties. In addition, intensive studies on inclusion characteristics of natural gems could identify their geographical origins and provide valuable information on gem synthesis. In this paper syn thetic gems (synthetic star-spangled sapphire and emerald) and natural gems from various loca tions including natural sapphire from Thailand and Australia, and natural aquamerine from Mu fushan, Hunan Province, and Ailaoshan, Yunnan Province, were selected for the comparative study of inclusions. Significant research results have been achieved, thus providing the impor tant basis for distinguishing natural from synthetic gems.

  17. Mechanical and ultrastructural evaluation of quartz post-endodontic reconstructions.

    Science.gov (United States)

    Majori, M; Bedini, R; Altamura, C; Filippini, P; Caiazza, S

    2004-01-01

    Aesthetics is a very important element in dentistry, but requires the support of good mechanical performance. Quartz fiber used in post-endodontic reconstruction is an aesthetic material, although there is little research concerning its mechanical properties. This study evaluated the retentive property of post-endodontic reconstruction, composed of a quartz fiber post. Different thermal stresses were applied in vitro to post-endodontic reconstructions, in order to simulate oral thermal action on post-system dental structure linkage. We chose 30 human extracted teeth, endodontically treated and restored, and then divided them into three groups of 10 teeth. A different treatment was applied to each group before mechanical testing: in the 1st group no treatment was done (controls); in the 2nd group teeth were subjected, in a climatic chamber, to 10 thermo-cycles between 4 degrees C and 58 degrees C; in the 3rd group teeth were stored in a saline solution at 37 degrees C for 48 hr. The teeth then underwent tensile shear stress tests at break point using a computerized electronic dynamometer. After mechanical testing, two teeth from each group were longitudinally half-sectioned, sputter-coated in gold and observed by scanning electron microscopy (SEM). The extracted quartz fiber post of each tooth also underwent SEM observation. Mechanical test results demonstrated that thermal cyclic variations could affect bond stability between dental structures and posts in quartz fiber reconstructions, whereas their bond strength seemed unaffected by humidity increases. Quartz fiber post SEM observation demonstrated a homogeneous structure and a regular fiber disposition. Dental root canal morphology SEM images always showed a different thickness in the cement layer. (Journal of Applied Biomaterials & Biomechanics 2004; 2: 156-61).

  18. Phototoxic maculopathy induced by quartz infrared heat lamp

    Science.gov (United States)

    Zheng, Xinhua; Xie, Ping; Hu, Zizhong; Zhang, Weiwei; Liang, Kang; Wang, Xiuying; Liu, Qinghuai

    2017-01-01

    Abstract Rationale: A large proportion of the output of quartz infrared heat lamps is emitted as infrared radiation (IR). Retinal damage induced by IR-A and visible light on arc welders has been reported. However, case reports of retinal damage caused by quartz infrared heat lamps are rare. To the best of our knowledge, this is the first reported case of phototoxic maculopathy induced by quartz infrared heat lamps. Patient concerns: We report a female with a 1-month history of progressive blurred vision and dysmorphopsia in her right eye after improper staring at the tubes of a quartz infrared heater. Her best corrected visual acuity of the right eye was 20/32. Optical coherence tomography revealed a defect from the ellipsoid zone to retinal pigment epithelium (RPE)/Bruch's complex layer with a diameter of 360mmat its widest. P1 amplitudes in the two central concentric rings were reduced as assessed by multifocal electroretinography. Diagnoses: The patient was diagnosed with phototoxic maculopathy. Interventions: The patient was advised to cease all exposure to the infrared heater and was treated with peribulbar injections of methylprednisolone, oral Pancreatic Kininogenase, and oral Mecobalamin. Outcomes: Ten months later, her BCVA improved to 20/20. All examination results returned to normal except for a small residual defect in the interdigitation zone and RPE/Bruch's complex layer in her optical coherence tomography. Lessons: Light emitted by quartz infrared heat lamps may cause damage to the retina through photothermal and photochemical means. The public is insufficiently aware of the hazard potential of infrared heat lamps and other IR-A sources on human retina. PMID:28099337

  19. Evaluating flow laws for dynamically recrystallized quartz based on field data

    Science.gov (United States)

    Peters, Max; Herwegh, Marco

    2013-04-01

    The extrapolation of experimentally controlled deformation conditions, and the resulting relations between physical parameters acting during ductile deformation, to nature is considered controversial (see Herwegh et al., 2005 and references therein). Whereas the relationship between flow stress and recrystallized grain size can be empirically derived from lab experiments using paleopiezometers (e.g. Stipp & Tullis, 2003), the relation between recrystallized grain size, strain rate, differential stress, temperature and activation energy for dislocation creep requires further constraints. For these relations, various power law flow laws for dynamically recrystallized quartz were proposed over the past years (Paterson & Luan, 1990; Luan & Paterson, 1992; Gleason & Tullis, 1995; Hirth et al., 2001, Rutter & Brodie, 2004). The variations in the flow laws are mainly characterized by different starting materials, experimental conditions, the activation energy for dislocation creep and the stress exponent n. In this study we compare and evaluate experimentally derived flow laws regarding their reliability for the prediction of rheology of background deformation of naturally deformed crystalline samples from mylonites of the Aar massif (Swiss Central Alps). The majority of samples comprises highly deformed rocks (e.g. Central Aare granite), which exhibit severe grain size reduction. This reduction dominantly occurred by subgrain rotation (SGR), in the case of low temperature overprint by bulging recrystallization (BLG). Towards elevated temperatures, grain boundary migration (GBM) and SGR recrystallization were active. Along the metamorphic gradient (300 - 475°C) quartz microstructures and associated recrystallized grain size distributions indicate steady state mean grain sizes. The quantification of the metamorphic gradient (temperature, pressure, water fugacity) over the sampling area allowed the application of flow laws, yielding variations of 6 orders of magnitude in

  20. Fe-N{sub x}/C assisted chemical–mechanical polishing for improving the removal rate of sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Li, E-mail: xl0522@126.com [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/Nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Zou, Chunli; Shi, Xiaolei [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/Nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Pan, Guoshun, E-mail: pangs@tsinghua.edu.cn [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/Nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Luo, Guihai; Zhou, Yan [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/Nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China)

    2015-07-15

    Highlights: • A novel non-noble metal catalyst (Fe-N{sub x}/C) was prepared. • Fe-N{sub x}/C shows remarkable catalytic activity for improving the removal rate of sapphire in alkaline solution. • The optimum CMP removal by Fe-N{sub x}/C yielded a superior surface finish of 0.078 nm the average roughness. • Fe{sub 2}O{sub 3}, Fe{sub 3}O{sub 4}, pyridinic N as well as pyrrolic N group possibly serving as the catalytic sites. • A soft hydration layer (boehmite, AlO(OH)) was generated on the surface of sapphire during CMP process. - Abstract: In this paper, a novel non-noble metal catalyst (Fe-N{sub x}/C) is used to improve the removal mass of sapphire as well as obtain atomically smooth sapphire wafer surfaces. The results indicate that Fe-N{sub x}/C shows good catalytic activity towards sapphire removal rate. And the material removal rates (MRRs) are found to vary with the catalyst content in the polishing fluid. Especially that when the polishing slurry mixes with 16 ppm Fe-N{sub x}/C shows the maximum MRR and its removal mass of sapphire is 38.43 nm/min, more than 15.44% larger than traditional CMP using the colloidal silicon dioxide (SiO{sub 2}) without Fe-N{sub x}/C. Catalyst-assisted chemical–mechanical polishing of sapphire is studied with X-ray photoelectron spectroscopy (XPS). It is found that the formation of a soft hydration layer (boehmite, γ-AlOOH or γ-AlO(OH)) on sapphire surface facilitates the material removal and achieving fine surface finish on basal plane. Abrasives (colloid silica together with magnetite, ingredient of Fe-N{sub x}/C) with a hardness between boehmite and sapphire polish the c-plane of sapphire with good surface finish and efficient removal. Fe{sub 2}O{sub 3}, Fe{sub 3}O{sub 4}, pyridinic N as well as pyrrolic N group would be the catalytical active sites and accelerate this process. Surface quality is characterized with atomic force microscopy (AFM). The optimum CMP removal by Fe-N{sub x}/C also yields a superior

  1. The effect of experiment geometry on the mechanism and rate of dissolution of quartz in basanite at 0.5GPa and 1350°C

    Science.gov (United States)

    Shaw, Cliff S. J.

    Mineral dissolution is an important factor in many magmatic processes such as melting, assimilation and magma mixing. Since it is not possible to determine dissolution rates or mechanisms from natural samples, experimental measurements are very useful. However, the geometry of the crystal-melt system can have a large effect on the measured rate, depending on whether the contaminated melt formed during dissolution is gravitationally stable or unstable. This study examines the effects of the crystal-melt geometry on the dissolution rate and mechanism. The experiments were performed using basanite melt and cylinders and spheres prepared from a single crystal of natural quartz. All of the experiments were performed in the piston cylinder apparatus at 0.5GPa and 1350°C. Four crystal-melt geometries were used: (1) quartz cylinders on top of a column of melt; (2) quartz cylinders beneath a column of basanite melt; (3) quartz cylinders in the middle of column of melt; (4) quartz spheres on top of a column of basanite melt. These geometries allow an examination of non-convective, convective and mixed non-convective/convective dissolution. Sphere experiments were included, as this has been the most commonly used geometry in previous experimental studies. In all of the experiments quartz dissolves directly into the basanite without formation of cristobalite or tridymite. Quartz on top of a column of melt dissolves at a rate almost proportional to the square root of time and forms a silica-rich compositional boundary layer that is gravitationally stable. All of the samples show well-defined compositional gradients in the boundary layer; however, the melt at the interface varies in composition with time and plots of concentration as a function of distance normalized to time show that the diffusion rate of SiO2 increases with time. These data suggest that the rate-controlling step during quartz dissolution is interface reaction rather than cation diffusion. Quartz on the bottom

  2. Towards improvement of aluminium assay in quartz for in situ cosmogenic 26Al analysis at ANSTO

    Science.gov (United States)

    Fujioka, Toshiyuki; Fink, David; Mifsud, Charles

    2015-10-01

    Accuracy and precision in the measurement of natural aluminium abundances in quartz can affect the reliability of 26Al exposure dating and 26Al/10Be burial dating. At ANSTO, aliquots extracted from the HF solutions of dissolved quartz are treated in our laboratory, whereas ICP-OES analysis is performed at a commercial laboratory. The long-term inter-run reproducibility of our in-house standards show a limiting precision in Al measurements of 3-4% (1σ), which is lower than the claimed precision of Al analysis by ICP-OES. This indicates that unaccounted random errors are incorporated during our aliquot preparation. In this study, we performed several controlled tests to investigate effects of possible inconsistencies and variances during our aliquot preparation procedure. The results indicate that our procedure is robust against any subtle change in the preparation procedure, e.g., fuming temperatures, fuming reagents, and drying conditions. We found that the density of the solutions dispatched for ICP analysis is occasionally variable due to the presence of residual fuming reagents in the solution. A comparison of the results between the calibration curve and standard addition methods show that the former results are consistently lower than the latter by up to ∼14%. Similar offsets have been reported by previous studies. The reason for these discrepancies is mostly likely matrix effect, which is not accounted for by the calibration curve method. Further tests by varying matrix with impurities such as HF, HClO4, H2SO4 and Si identified that Si could cause lower offset in Al measurements; however, our ICP solutions are confirmed to be free from Si and the cause of matrix effect remains to be investigated. Hence, care must be taken for the measurement of Al concentrations in quartz by ICP-OES, either by ensuring that matrix effect is fully accounted for or by routinely employing standard additions when required.

  3. First-principles simulation of Raman spectra and structural properties of quartz up to 5 GPa

    Science.gov (United States)

    Liu, Lei; Lv, Chao-Jia; Zhuang, Chun-Qiang; Yi, Li; Liu, Hong; Du, Jian-Guo

    2015-12-01

    The crystal structure and Raman spectra of quartz are calculated by using first-principles method in a pressure range from 0 to 5 GPa. The results show that the lattice constants (a, c, and V) decrease with increasing pressure and the a-axis is more compressible than the c axis. The Si-O bond distance decreases with increasing pressure, which is in contrast to experimental results reported by Hazen et al. [Hazen R M, Finger L W, Hemley R J and Mao H K 1989 Solid State Communications 725 507-511], and Glinnemann et al. [Glinnemann J, King H E Jr, Schulz H, Hahn T, La Placa S J and Dacol F 1992 Z. Kristallogr. 198 177-212]. The most striking changes are of inter-tetrahedral O-O distances and Si-O-Si angles. The volume of the tetrahedron decreased by 0.9% (from 0 to 5 GPa), which suggests that it is relatively rigid. Vibrational models of the quartz modes are identified by visualizing the associated atomic motions. Raman vibrations are mainly controlled by the deformation of the tetrahedron and the changes in the Si-O-Si bonds. Vibrational directions and intensities of atoms in all Raman modes just show little deviations when pressure increases from 0 to 5 GPa. The pressure derivatives (dνi/dP) of the 12 Raman frequencies are obtained at 0 GPa-5 GPa. The calculated results show that first-principles methods can well describe the high-pressure structural properties and Raman spectra of quartz. The combination of first-principles simulations of the Raman frequencies of minerals and Raman spectroscopy experiments is a useful tool for exploring the stress conditions within the Earth. Project supported by the Key Laboratory of Earthquake Prediction, Institute of Earthquake Science, China Earthquake Administration (CEA) (Grant No. 2012IES010201) and the National Natural Science Foundation of China (Grant Nos. 41174071 and 41373060).

  4. Optically stimulated exoelectron emission processes in quartz: comparison of experiment and theory

    DEFF Research Database (Denmark)

    Pagonis, V.; Ankjærgaard, Christina; Murray, A.S.

    2009-01-01

    Recent experiments have demonstrated that it is possible to measure optically stimulated exoelectron emission (OSE) signals simultaneously with optically stimulated luminescence (OSL) from quartz samples. These experiments provide valuable information on the charge movement in quartz grains. Two...

  5. Properties and behavior of quartz for the silicon process

    Energy Technology Data Exchange (ETDEWEB)

    Aasly, Kurt

    2008-07-01

    This PhD-thesis is a result of the study on important properties of quartz as a raw material for the metallurgical production of ferrosilicon and silicon metal. This includes defining mechanical properties important for the size reduction experienced during transport and storage and thermo-mechanical properties of quartz that is important for how the quartz reacts to the high temperatures experienced as it is charged on the furnace. Additionally, softening properties of quartz have been briefly discussed in some of the papers. Another important goal has been to test analytical and experimental methods for investigating the various properties. The investigations of important factors for the mechanical properties of ores and industrial minerals have been carried out as a literature study. The mining operation and transport from mine to smelter has been discussed and several factors that are significant for achieving best possible mechanical properties of the quartz have been identified. The most important factors are related to production in the mine and processing plant, which should be carefully planned to minimize the amount of blast-induced damage in the rock and thus achieve the best possible mechanical strength of the raw material. The amount of fines can be minimized by controlling the handling of the raw materials during the transport and storage. It is especially important to avoid high drops, both high single drops and accumulated height of all the drops in total. Investigations of the thermo-mechanical properties of quartz have been carried out by using different experimental and characterization methods. The petrographic investigations of the raw materials by polarized light microscopy have been important. Thermo-mechanical investigations have been high-temperature microthermometry and shock heating of quartz samples in an induction furnace with subsequent investigations of the heated material. The subsequent investigation included polarized- and

  6. The role of quartz in the origin of optical activity on earth.

    Science.gov (United States)

    Evgenii, K; Wolfram, T

    2000-10-01

    A thorough analysis of literature data on distribution of right and left quartz in many locations on the surface of Earth indicates that quartz enantiomorph crystals are distributed in equal amounts in all locations. Therefore optically active quartz crystals of one or the other enantiomorph could not serve as the source of homochirality in the evolution of biosphere. Hence the calculation of a PVED based on published 'small excess of left quartz crystals' on Earth lacks a sound physical basis.

  7. Absorption and emission spectroscopy in natural and synthetic corundum

    Science.gov (United States)

    Spinolo, G.; Palanza, V.; Ledonne, A.; Paleari, A.

    2009-04-01

    In the frame of an extensive project on the optical characterization of the many varieties of corundum (see:www.gemdata.mater.unimib.it ) we reconsidered the current interpretation of the absorption spectra with particular attention to the bands attributed to the IVCT mechanism Fe2+→ Fe3+ and Fe2+→Ti4+. A detailed study was devoted to natural metamorphic and Verneuil synthetic pale blue sapphires . In that paper (I.Fontana et al 2008) we gave experimental evidence that the band at 17500 cm-1 often attributed to Fe2+→Ti4+ IVCT transitions is in reality due to the 4T2 crystal field transition of Cr3+ partially overlapped by the 2E of Ti3+. The results of radio and photoluminescence excitation experiments obtained there, led us to propose that the color of these sapphires is mainly due to Cr in its two valence states ; Ti 3+ and Fe3+ have a minor role. After those encouraging results, we decided to apply the same approach to the study of deep blue and yellow sapphires of magmatic origin. Evaluation of impurity ion concentration by EDXRF revealed that in all these samples the concentration of Fe is quite high (around 1%) while Cr and Ti are barely detectable. Characteristic of the absorption spectra of deep blue samples is the dominant presence of the 5E spin allowed transition of Fe2+; Fe3+ has a minor role due to the fact that all d5 transitions are spin forbidden and ,consequently, very weak. In yellow sapphires Fe is totally in its 3+ valence state. In these cases, the color from yellow to blue, sometimes even within the same sample, depends. on oxidizing or reducing growth conditions. Even if the concentrations of Cr and Ti are very low, their characteristic emissions are the only ones observable down to 10000 cm-1 in radio and photoluminescence spectra. This piece of evidence suggested us to propose for the absorption bands present in the 14000 to 21000 cm-1 range, often attributed to IVCT, the same attribution given to the analogous bands in metamorphic

  8. 30 CFR 90.101 - Respirable dust standard when quartz is present.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Respirable dust standard when quartz is present... quartz is present. When the respirable dust in the mine atmosphere of the active workings to which a Part 90 miner is exposed contains more than 5 percent quartz, the operator shall continuously maintain...

  9. 30 CFR 71.101 - Respirable dust standard when quartz is present.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Respirable dust standard when quartz is present... UNDERGROUND COAL MINES Dust Standards § 71.101 Respirable dust standard when quartz is present. When the respirable dust in the mine atmosphere of the active workings contains more than 5 percent quartz,...

  10. 30 CFR 70.101 - Respirable dust standard when quartz is present.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Respirable dust standard when quartz is present... Respirable dust standard when quartz is present. When the respirable dust in the mine atmosphere of the active workings contains more than 5 percent quartz, the operator shall continuously maintain the...

  11. Measurement of the dose in quartz in the presence of feldspar contamination

    DEFF Research Database (Denmark)

    Wallinga, J.; Murray, A.S.; Bøtter-Jensen, L.

    2002-01-01

    , without seriously affecting the quartz OSL signal. A single-aliquot regenerative-dose protocol is proposed which, in our samples, allows accurate measurement of the dose in quartz in the presence of feldspar contamination. The protocol also has potential use for quartz dose determination in mixed...

  12. First Natural Occurrence of Coesite.

    Science.gov (United States)

    Chao, E C; Shoemaker, E M; Madsen, B M

    1960-07-22

    Coesite, the high-pressure polymorph of SiO(2), hitherto known only as a synthetic compound, is identified as an abundant mineral in sheared Coconino sandstone at Meteor Crater, Arizona. This natural occurrence has important bearing on the recognition of meteorite impact craters in quartz-bearing geologic formations.

  13. A Multi-Fork Z-Axis Quartz Micromachined Gyroscope

    Directory of Open Access Journals (Sweden)

    Aiying Yang

    2013-09-01

    Full Text Available A novel multi-fork z-axis gyroscope is presented in this paper. Different from traditional quartz gyroscopes, the lateral electrodes of the sense beam can be arranged in simple patterns; as a result, the fabrication is simplified. High sensitivity is achieved by the multi-fork design. The working principles are introduced, while the finite element method (FEM is used to simulate the modal and sensitivity. A quartz fork is fabricated, and a prototype is assembled. Impedance testing shows that the drive frequency and sense frequency are similar to the simulations, and the quality factor is approximately 10,000 in air. The scale factor is measured to be 18.134 mV/(°/s and the nonlinearity is 0.40% in a full-scale input range of ±250 °/s.

  14. Deposition and alignment of cells on laser-patterned quartz

    Energy Technology Data Exchange (ETDEWEB)

    George, Sajan D., E-mail: sajan.george@manipal.edu [Centre for Atomic and Molecular Physics, Manipal University, Manipal 576 104 (India); Ladiwala, Uma, E-mail: brainwave@cbs.ac.in [UM-DAE Centre for Excellence in Basic Sciences, Kalina Campus, Mumbai 400 098 (India); Thomas, John; Bankapur, Aseefhali; Chidangil, Santhosh [Centre for Atomic and Molecular Physics, Manipal University, Manipal 576 104 (India); Mathur, Deepak [Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005 (India)

    2014-06-01

    Linear grooves have been laser-written on quartz surfaces using ultrashort (50 fs) pulses of 800 nm light. Measurements of water contact angle indicate that laser patterning makes the quartz surface more hydrophilic. Fibroblast cells were cultured on such laser-written surfaces; they were observed to align preferentially along the direction of the laser written grooves (width ∼2 μm. Raman spectroscopy results indicate that there are no chemical changes induced in the surface upon our laser writing. Most unexpectedly, there are also no chemical changes induced in the cells that are spatially aligned along the laser-written grooves. Atomic force microscopy measurements confirm that our laser-writing induces dramatic enhancement of surface roughness along the grooves, and the cells appear to respond to this. Thus, cell alignment seems to be in response to physical cues rather than chemical signals.

  15. New developments in THz quartz enhanced photoacoustic spectroscopy

    Science.gov (United States)

    Spagnolo, Vincenzo; Patimisco, Pietro; Sampaolo, Angelo; Giglio, Marilena; Vitiello, Miriam S.; Scamarcio, Gaetano; Tittel, Frank K.

    2016-09-01

    We will report on new developments of quartz-enhanced photo-acoustic (QEPAS) sensor employing THz quantum cascade laser (QCLs). The extension of the QEPAS technique in the THz range was made possible by the realization of custom made QTFs. With the aim to improve the QTF acousto-electric transduction efficiency, we designed and realized new QTF designs. A detailed analysis of the quality factor, the resonance frequency and the electrical resistance of custom quartz tuning forks (QTFs) with different geometrical parameters is reported. The custom QTFs were employed in QEPAS sensors using THz QCLs as the laser excitation sources and targeting CH3OH and H2S. Minimum detection limits of a few tens of ppb and normalized noise equivalent absorption factors down to 3.75×10-11 cm-1W/Hz½ were achieved.

  16. A multi-fork z-axis quartz micromachined gyroscope.

    Science.gov (United States)

    Feng, Lihui; Zhao, Ke; Sun, Yunan; Cui, Jianmin; Cui, Fang; Yang, Aiying

    2013-01-01

    A novel multi-fork z-axis gyroscope is presented in this paper. Different from traditional quartz gyroscopes, the lateral electrodes of the sense beam can be arranged in simple patterns; as a result, the fabrication is simplified. High sensitivity is achieved by the multi-fork design. The working principles are introduced, while the finite element method (FEM) is used to simulate the modal and sensitivity. A quartz fork is fabricated, and a prototype is assembled. Impedance testing shows that the drive frequency and sense frequency are similar to the simulations, and the quality factor is approximately 10,000 in air. The scale factor is measured to be 18.134 mV/(°/s) and the nonlinearity is 0.40% in a full-scale input range of ±250 °/s.

  17. Annealing Effect on Photovoltages of Quartz Single Crystals

    Institute of Scientific and Technical Information of China (English)

    TIAN Lu; ZHAO Song-Qing; ZHAO Kun

    2010-01-01

    @@ We investigate the photovoltaic effects of quartz single crystals annealed at high temperatures in ambient atmosphere.The open-circuit photovoltages and surface morphologies strongly depend on the heating treatments.When the annealing temperature increases from room temperature to 900℃,the rms roughness of quartz single crystal wafers increases from 0.207 to 1.011 nm.In addition,the photovoltages decrease from 1.994#V at room temperature to 1.551 μ V after treated at 500℃,and then increase up to 9.8μV after annealed at 900℃.The inner mechanism of the present photovoltaic response and surface morphologies is discussed.

  18. Coupled isomorphic substitution and exsolution of pyroxene, rutile, apatite and quartz in supersilicic garnet

    Institute of Scientific and Technical Information of China (English)

    YANG Jiaxi; LIU Liang

    2004-01-01

    Dissolution of pyroxene in garnet at ultrahigh pressures produces supersilicic garnet with the coupled substitutions of SiⅥ + MⅥ= AlⅥ + AlⅥ and SiⅥ + NaⅧ=AlⅥ + MⅧ, which are enhanced by rising pressure. The supersilicic garnet and exsolution of pyroxene, rutile, apatite and quartz in garnet during decompression were found in natural rocks, pointing to the importance in studying mantle-derived rocks and ultrahigh pressure metamorphism related to plate deep subduction. Ti, P, K and H2O enters garnet via the substitutions of Ti = Si, PⅣ+NaⅧ = SiⅣ+ CaⅧ, SiⅥ+KⅧ = AlⅥ+MⅧ, and [(OH)4]4- = [SiO4]4- or [4H]4+ = Si4+ respectively. The possible entering of Eskola pyroxene component M0.5AlSi2O6 in clinopyroxene, together with the common pyroxene component M2Si2O6, into garnet can lead to the presence of the substitution of SiⅥ + 0.5□Ⅷ= AlⅥ + 0.5MⅧ in garnet structure, which plays a key role in the exsolution of rutile, apatite and quartz in garnet. Two new breakdown reactions are thus proposed on the basis of the new coupled substitution, which can be regarded as a theoretical model for the exsolution of the 3 minerals in garnet. The real exsolution may be a combination of several breakdown reactions.

  19. Origin of sapphires from a lamprophyre dike at Yogo Gulch, Montana, USA: Clues from their melt inclusions

    Science.gov (United States)

    Palke, Aaron C.; Renfro, Nathan D.; Berg, Richard B.

    2016-09-01

    Gem corundum (sapphire) has been mined from an ultramafic lamprophyre dike at Yogo Gulch in central Montana for over 100 years. The sapphires bear signs of corrosion showing that they were not in equilibrium with the lamprophyre that transported them; however, their genesis is poorly understood. We report here the observation of minute glassy melt inclusions in Yogo sapphires. These inclusions are Na- and Ca-rich, Fe-, Mg-, and K-poor silicate glasses with compositions unlike that of the host lamprophyre. Larger, recrystallized melt inclusions contain analcime and calcite drawing a striking resemblance to leucocratic ocelli in the lamprophyre. We suggest here that sapphires formed through partial melting of Al-rich rocks, likely as the lamprophyre pooled at the base of the continental crust. This idea is corroborated by MELTS calculations on a kyanite-eclogite protolith which was presumably derived from a troctolite precursor. These calculations suggest that corundum can form through peritectic melting of kyanite. Linking the melt inclusions petrologically to the lamprophyre represents a significant advancement in our understanding of sapphire genesis and sheds light on how mantle-derived magmas may interact with the continental crust on their ascent to the surface.

  20. Growth and characterization of VO{sub 2}/p-GaN/sapphire heterostructure with phase transition properties

    Energy Technology Data Exchange (ETDEWEB)

    Bian, Jiming, E-mail: jmbian@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Key Laboratory of Inorganic Coating Materials, Chinese Academy of Sciences, Shanghai 200050. China (China); Wang, Minhuan; Miao, Lihua; Li, Xiaoxuan; Luo, Yingmin [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Zhang, Dong [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); New Energy Source Research Center of Shenyang Institute of Engineering, Shenyang 110136 (China); Zhang, Yuzhi [Key Laboratory of Inorganic Coating Materials, Chinese Academy of Sciences, Shanghai 200050. China (China)

    2015-12-01

    Highlights: • VO{sub 2} films were deposited on p-GaN/sapphire substrates by PLD. • A well-defined VO{sub 2}/p-GaN/sapphire interface was observed. • The valence state of V in VO{sub 2} films was confirmed by XPS analyses. • A distinct reversible SMT phase transition behavior was observed. - Abstract: High quality pure phase VO{sub 2} films were deposited on p-GaN/sapphire substrates by pulsed laser deposition (PLD). A well-defined interface with dense and uniform morphology was observed in the as-grown VO{sub 2}/p-GaN/sapphire heterostructure. The X-ray photoelectron spectroscopy (XPS) analyses confirmed the valence state of vanadium (V) in VO{sub 2} films was principally composed of V{sup 4+} with trace amount of V{sup 5+}, no other valence state of V was detected. Meanwhile, a distinct reversible semiconductor-to-metal (SMT) phase transition with resistance change up to nearly three orders of magnitude was observed in the temperature dependent electrical resistance measurement, which was comparable to the high quality VO{sub 2} film grown directly on sapphire substrates. Our present findings will give a deeper insight into the physical mechanism behind the exotic characteristics of VO{sub 2}/p-GaN heterostructure, and further motivate research in novel devices with combined functional properties of both correlated oxide and wide bandgap nitride semiconductors.

  1. Dependence of adhesion strength between GaN LEDs and sapphire substrate on power density of UV laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Junsu [Department of Nano-Manufacturing Technology, Korea Institute of Machinery and Materials, 156 Gajeongbuk-Ro, Yuseong-Gu, Daejeon 34103 (Korea, Republic of); Sin, Young-Gwan [Department of Nano-Mechatronics, Korea University of Science and Technology (UST), 217 Gajeong-Ro, Yuseong-Gu, Daejeon 34113 (Korea, Republic of); Kim, Jae-Hyun [Department of Nano-Mechanics, Korea Institute of Machinery and Materials, 156 Gajeongbuk-Ro, Yuseong-Gu, Daejeon 34103 (Korea, Republic of); Kim, Jaegu, E-mail: gugu99@kimm.re.kr [Department of Nano-Manufacturing Technology, Korea Institute of Machinery and Materials, 156 Gajeongbuk-Ro, Yuseong-Gu, Daejeon 34103 (Korea, Republic of)

    2016-10-30

    Highlights: • Fundamental relationship between laser irradiation and adhesion strength, between gallium-nitride light emitted diode and sapphire substrate, is proposed during selective laser lift-off. • Two competing mechanisms affect adhesion at the irradiated interface between the GaN LED and sapphire substrate. • Ga precipitation caused by thermal decomposition and roughened interface caused by thermal damage lead to the considerable difference of adhesion strength at the interface. - Abstract: Selective laser lift-off (SLLO) is an innovative technology used to manufacture and repair micro-light-emitting diode (LED) displays. In SLLO, laser is irradiated to selectively separate micro-LED devices from a transparent sapphire substrate. The light source used is an ultraviolet (UV) laser with a wavelength of 266 nm, pulse duration of 20 ns, and repetition rate of 30 kHz. Controlled adhesion between a LED and the substrate is key for a SLLO process with high yield and reliability. This study examined the fundamental relationship between adhesion and laser irradiation. Two competing mechanisms affect adhesion at the irradiated interface between the GaN LED and sapphire substrate: Ga precipitation caused by the thermal decomposition of GaN and roughened interface caused by thermal damage on the sapphire. The competition between these two mechanisms leads to a non-trivial SLLO condition that needs optimization. This study helps understand the SLLO process, and accelerate the development of a process for manufacturing micro-LED displays via SLLO for future applications.

  2. Investigation of a direction sensitive sapphire detector stack at the 5 GeV electron beam at DESY-II

    CERN Document Server

    Karacheban, O; Hempel, M; Henschel, H; Lange, W; Leonard, J L; Levy, I; Lohmann, W; Schuwalow, S

    2015-01-01

    Extremely radiation hard sensors are needed in particle physics experiments to instrument the region near the beam pipe. Examples are beam halo and beam loss monitoring systems at the Large Hadron Collider, FLASH or XFEL. Artificial diamond sensors are currently widely used as sensors in these systems. In this paper single crystal sapphire sensors are considered as a promising alternative. Industrially grown sapphire wafers are available in large sizes, are of low cost and, like diamond sensors, can be operated without cooling. Here we present results of an irradiation study done with sapphire sensors in a high intensity low energy electron beam. Then, a multichannel direction-sensitive sapphire detector stack is described. It comprises 8 sapphire plates of 1 cm^2 size and 525 micrometer thickness, metallized on both sides, and apposed to form a stack. Each second metal layer is supplied with a bias voltage, and the layers in between are connected to charge-sensitive preamplifiers. The performance of the dete...

  3. Plasma polymerized allylamine coated quartz particles for humic acid removal.

    Science.gov (United States)

    Jarvis, Karyn L; Majewski, Peter

    2012-08-15

    Allylamine plasma polymerization has been used to modify the surface of quartz particles for humic acid removal via an inductively coupled rotating barrel plasma reactor. Plasma polymerized allylamine (ppAA) films were deposited at a power of 25 W, allylamine flow rate of 4.4 sccm and polymerization times of 5-60 min. The influence of polymerization time on surface chemistry was investigated via X-ray photoelectron spectroscopy (XPS), time of flight secondary ion mass spectrometry (ToF-SIMS) and electrokinetic analysis. Acid orange 7 adsorption/desorption quantified the number of surface amine groups. Humic acid removal via ppAA quartz particles was examined by varying pH, removal time, humic acid concentration, and particle mass. Increasing the polymerization time increased the concentration of amine groups on the ppAA quartz surface, thus also increasing the isoelectric point. ToF-SIMS demonstrated uniform distribution of amine groups across the particle surface. Greatest humic acid removal was observed at pH 5 due to electrostatic attraction. At higher pH values, for longer polymerization times, humic acid removal was also observed due to hydrogen bonding. Increasing the initial humic acid concentration increased the mass of humic acid removed, with longer polymerization times exhibiting the greatest increases. Plasma polymerization using a rotating plasma reactor has shown to be a successful method for modifying quartz particles for the removal of humic acid. Further development of the plasma polymerization process and investigation of additional contaminants will aid in the development of a low cost water treatment system.

  4. Evaluation of the approach to respirable quartz exposure control in U.S. coal mines.

    Science.gov (United States)

    Joy, Gerald J

    2012-01-01

    Occupational exposure to high levels of respirable quartz can result in respiratory and other diseases in humans. The Mine Safety and Health Adminstration (MSHA) regulates exposure to respirable quartz in coal mines indirectly through reductions in the respirable coal mine dust exposure limit based on the content of quartz in the airborne respirable dust. This reduction is implemented when the quartz content of airborne respirable dust exceeds 5% by weight. The intent of this dust standard reduction is to restrict miners' exposure to respirable quartz to a time-weighted average concentration of 100 μg/m(3). The effectiveness of this indirect approach to control quartz exposure was evaluated by analyzing respirable dust samples collected by MSHA inspectors from 1995 through 2008. The performance of the current regulatory approach was found to be lacking due to the use of a variable property-quartz content in airborne dust-to establish a standard for subsequent exposures. In one situation, 11.7% (4370/37,346) of samples that were below the applicable respirable coal mine dust exposure limit exceeded 100 μg/m(3) quartz. In a second situation, 4.4% (895/20,560) of samples with 5% or less quartz content in the airborne respirable dust exceeded 100 μg/m(3) quartz. In these two situations, the samples exceeding 100 μg/m(3) quartz were not subject to any potential compliance action. Therefore, the current respirable quartz exposure control approach does not reliably maintain miner exposure below 100 μg/m(3) quartz. A separate and specific respirable quartz exposure standard may improve control of coal miners' occupational exposure to respirable quartz.

  5. Silicon compounds in solution during bacterial degradation of quartz

    Energy Technology Data Exchange (ETDEWEB)

    Avakyan, Z.A.; Belkanova, N.P.; Karavayko, G.I.; Piskunov, V.P.

    A study was made of the form of silicon compounds in solution in the following systems: distilled water-exopolysaccharides of Bacillus mucilaginosus-monomeric silica; distilled water-suspension of B. mucilaginosus cells-quartz; culture fluids-growing B. mucilaginosus or Thiobacillus thioparus cultures-quartz. In control variants, which contained no exopolysaccharides or bacteria, all of the silicon in solution is demonstrable with the reaction with molybdic acid in the form of monosilicic acid and, perhaps, its lower oligomers. The presence of exopolysaccharides or bacteria leads to the appearance of three forms of silicon compounds: monomeric, polymeric as demonstrable by reaction with molybdic acid after alkaline hydrolysis, and bound, which is demonstrable only by the sintering method. The pH, concentrations of exopolysaccharides and silicon are factors that control the proportion of these forms of silica in the systems studied with exopolysaccharides and resting cells. An increase in the concentration of polysaccharides in the system, as well as changes in medium reaction in the alkaline direction, shift equilibrium toward the formation of the bound form of silica. The mechanism of microbiological degradation of quartz and the formation of silicon compounds is discussed.

  6. Improved electron probe microanalysis of trace elements in quartz

    Science.gov (United States)

    Donovan, John J.; Lowers, Heather; Rusk, Brian G.

    2011-01-01

    Quartz occurs in a wide range of geologic environments throughout the Earth's crust. The concentration and distribution of trace elements in quartz provide information such as temperature and other physical conditions of formation. Trace element analyses with modern electron-probe microanalysis (EPMA) instruments can achieve 99% confidence detection of ~100 ppm with fairly minimal effort for many elements in samples of low to moderate average atomic number such as many common oxides and silicates. However, trace element measurements below 100 ppm in many materials are limited, not only by the precision of the background measurement, but also by the accuracy with which background levels are determined. A new "blank" correction algorithm has been developed and tested on both Cameca and JEOL instruments, which applies a quantitative correction to the emitted X-ray intensities during the iteration of the sample matrix correction based on a zero level (or known trace) abundance calibration standard. This iterated blank correction, when combined with improved background fit models, and an "aggregate" intensity calculation utilizing multiple spectrometer intensities in software for greater geometric efficiency, yields a detection limit of 2 to 3 ppm for Ti and 6 to 7 ppm for Al in quartz at 99% t-test confidence with similar levels for absolute accuracy.

  7. Measurement and thermal modeling of sapphire substrate temperature at III-Nitride MOVPE conditions

    Science.gov (United States)

    Creighton, J. Randall; Coltrin, Michael E.; Figiel, Jeffrey J.

    2017-04-01

    Growth rates and alloy composition of AlGaN grown by MOVPE is often very temperature dependent due to the presence of gas-phase parasitic chemical processes. These processes make wafer temperature measurement highly important, but in fact such measurements are very difficult because of substrate transparency in the near-IR ( 900 nm) where conventional pyrometers detect radiation. The transparency problem can be solved by using a mid-IR pyrometer operating at a wavelength ( 7500 nm) where sapphire is opaque. We employ a mid-IR pyrometer to measure the sapphire wafer temperature and simultaneously a near-IR pyrometer to measure wafer pocket temperature, while varying reactor pressure in both a N2 and H2 ambient. Near 1300 °C, as the reactor pressure is lowered from 300 Torr to 10 Torr the wafer temperature drops dramatically, and the ∆T between the pocket and wafer increases from 20 °C to 250 °C. Without the mid-IR pyrometer the large wafer temperature change with pressure would not have been noted. In order to explain this behavior we have developed a quasi-2D thermal model that includes a proper accounting of the pressure-dependent thermal contact resistance, and also accounts for sapphire optical transmission. The model and experimental results demonstrate that at most growth conditions the majority of the heat is transported from the wafer pocket to the wafer via gas conduction, in the free molecular flow limit. In this limit gas conductivity is independent of gap size but first order in pressure, and can quantitatively explain results from 20 to 300 Torr. Further analysis yields a measure of the thermal accommodation coefficients; α(H2) =0.23, α(N2) =0.50, which are in the range typically measured.

  8. Effect of Ti:Sapphire-femtosecond laser on the surface roughness of ceramics.

    Science.gov (United States)

    Erdur, Emire Aybuke; Basciftci, Faruk Ayhan

    2015-12-01

    Some of these adult patients have ceramic crowns, to which orthodontists have concerns about bonding brackets. The aim of the present study was to evaluate the effect of a Ti:Sapphire femtosecond (fs) laser (Integra-C-3.5, Quantronix, NY) on the surface roughness of two ceramic surfaces (feldspathic and IPS Empress e-Max) and to compare results with those of two other lasers (Er:YAG and Nd:YAG) and conventional techniques, i.e., sandblasting (50 µm) and hydrofluoric (HF) acid. Ceramic discs were fabricated (n = 150) and divided into two groups, each of which was then divided into five subgroups prepared with Ti:Sapphire fs, Nd:YAG, or Er:YAG lasers, sandblasting, or HF acid (n = 15). The surface roughness of the ceramic discs was evaluated using a profilometer (Mitotoyo Surf Test SJ 201 P/M; Mitutoyo Corp, Japan) before and after each surface treatment. Three traces were recorded for each specimen at three different locations in each direction, providing nine measurements per sample, which were then averaged to obtain the surface roughness value. Data were analyzed using the Wilcoxon signed-rank test (P laser was associated with the highest mean roughness value. AFM images of the ceramic surfaces treated confirmed that the fs-laser-treated surfaces had the highest degree of irregularity. Within the limitations of this in vitro study, the Ti:Sapphire fs laser yielded the highest surface roughness and could be an alternative ceramic surface treatment to increase bond strength. © 2015 Wiley Periodicals, Inc.

  9. Microstructure characterization and optical properties of sapphire after helium ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Mian; Yang, Liang [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Shen, Huahai [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Liu, Wei [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Xiang, Xia, E-mail: xiaxiang@uestc.edu.cn [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Zheng, Wanguo, E-mail: wgzheng_caep@sina.com [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Guo, Decheng [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Huang, Jin [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Sun, Kai [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Yuan, Xiaodong, E-mail: yxd66my@163.com [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China)

    2015-06-15

    The (0 0 0 1) sapphire samples are irradiated with 60 keV helium ions at the fluences of 5 × 10{sup 16}, 1 × 10{sup 17}and 5 × 10{sup 17} ions/cm{sup 2} at room temperature. After implantation, two broad absorption bands at 320–460 and 480–700 nm are observed and their intensities increase with the increasing ion fluence. The grazing incidence X-ray diffraction results indicate that the {0 0 0 1} diffraction peaks of sapphire decrease and broaden due to the disorientation of the generated crystallites after ion irradiation. The microstructure evolution is examined by the scanning and transmission electron microscopes. The surface becomes rough because of the aggregation of helium bubbles and migration towards the surface. There is a lattice expansion up to ∼4.5% in the implanted area and the lattice distortion measured from dispersion of (1 1 0) diffraction is ∼4.6°. Such strain of crystal lattice is rather large and leads to contrast fluctuation at scale of 1–2 nm (the bubble size). The laser induced damage threshold (LIDT) is investigated to understand the effect of helium ion beam irradiation on the laser damage resistance of sapphire components and the results show that the LIDT decreases from 5.4 to 2.5 J/cm{sup 2} due to the absorptive color centers, helium bubbles and defects induced by helium ion implantation. The laser damage morphologies of samples before and after ion implantation are also presented.

  10. Voltage-controlled narrowband and wide, variable-range four-segment quartz crystal oscillator.

    Science.gov (United States)

    Ruslan, Ruzaini; Satoh, Tomio; Akitsu, Tetsuya

    2012-03-01

    In this work, our goal is to develop a voltage-controlled variable-frequency quartz crystal oscillator with narrowband response, wide, variable frequency range and the capacity to oscillate across the series resonance frequency using a four-segment configuration of a quartz crystal oscillator. In conventional quartz oscillators, the quartz resonator is inserted in the feedback loop between the input and the output of the active circuit, providing sufficient gain and the phase relation. In the oscillator developed here, the quartz crystal resonator is inserted between the loop circuit and the ground potential. The performance of the voltage-controlled variable-frequency oscillator is demonstrated across the series resonance frequency.

  11. Pulse formation and characteristics of the cw mode-locked titanium-doped sapphire laser

    Science.gov (United States)

    Zschocke, Wolfgang; Stamm, Uwe; Heumann, Ernst; Ledig, Mario; Guenzel, Uwe; Kvapil, Jiri; Koselja, Michael P.; Kubelka, Jiri

    1991-10-01

    We report on measurements of transient and steady-state pulse characteristics of an acousto- optically mode-locked titanium-doped sapphire laser. During the pulse evolution, oscillations in the pulse width and pulse energy are found. A steady state is reached after about 40 to 60 microsecond(s) . The steady-state pulse width is strongly influenced by the mode-locking loss as well as the intracavity bandwidth. Shortest pulses of typically 15 ps are obtained. The experiment is compared with results of a simple computer simulation.

  12. Long-term optical phase locking between femtosecond Ti:sapphire and Cr:forsterite lasers

    Science.gov (United States)

    Kobayashi, Yohei; Yoshitomi, Dai; Kakehata, Masayuki; Takada, Hideyuki; Torizuka, Kenji

    2005-09-01

    Long-term optical phase-coherent two-color femtosecond pulses were generated by use of passively timing-synchronized Ti:sapphire and Cr:forsterite lasers. The relative carrier-envelope phase relation was fixed by an active feedback loop. The accumulated phase noise from 10 mHz to 1 MHz of the locked beat note was 0.43 rad, showing tight phase locking. The optical frequency fluctuation between two femtosecond combs was submillihertz, with a 1 s averaged counter measurement over 3400 s, leading to a long-term femtosecond frequency-comb connection.

  13. A 10-Hz terawatt class Ti:sapphire laser system: Development and applications

    Indian Academy of Sciences (India)

    A K Sharma; J Smedley; T Tsang; T Rao

    2010-11-01

    We developed a two-stage Ti:sapphire laser system to generate 16 mJ/80 fs laser pulses at a pulse repetition rate of 10 Hz. The key deriver for the present design is implementing a highly efficient symmetric confocal pre-amplifier and employing a simple, inexpensive synchronization scheme relying only on a commercial digital delay generator. We characterized the amplified pulses in spatial, spectral and temporal domains. The laser system was used to investigate various nonlinear optical processes, and to modify the optical properties of metal and semiconductor surfaces. We are currently building a third amplifier to boost the laser power to the multi-terawatt range.

  14. Grating-coupled silicon-on-sapphire integrated slot waveguides operating at mid-infrared wavelengths.

    Science.gov (United States)

    Zou, Yi; Subbaraman, Harish; Chakravarty, Swapnajit; Xu, Xiaochuan; Hosseini, Amir; Lai, Wei-Cheng; Wray, Parker; Chen, Ray T

    2014-05-15

    We demonstrate subwavelength bidirectional grating (SWG) coupled slot waveguide fabricated in silicon-on-sapphire for transverse electric polarized wave operation at 3.4 μm wavelength. Coupling efficiency of 29% for SWG coupler is experimentally achieved. Propagation loss of 11  dB/cm has been experimentally obtained for slot waveguides. Two-step taper mode converters with an insertion loss of 0.13 dB are used to gradually convert the strip waveguide mode into slot waveguide mode.

  15. Autonomous cryogenic sapphire oscillators employing low vibration pulse-tube cryocoolers at NMIJ

    Science.gov (United States)

    Ikegami, Takeshi; Watabe, Ken-ichi; Yanagimachi, Shinya; Takamizawa, Akifumi; Hartnett, John G.

    2016-06-01

    Two liquid-helium-cooled cryogenic sapphire-resonator oscillators (CSOs), have been modified to operate using cryo-refrigerators and low-vibration cryostats. The Allan deviation of the first CSO was evaluated to be better than 2 x 10-15 for averaging times of 1 s to 30 000 s, which is better than that of the original liquid helium cooled CSO. The Allan deviation of the second CSO is better than 4 x 10-15 from 1 s to 6 000 s averaging time.

  16. Investigation of a GaN Nucleation Layer on a Patterned Sapphire Substrate

    Institute of Scientific and Technical Information of China (English)

    WU Meng; ZENG Yi-Ping; WANG Jun-Xi; HU Qiang

    2011-01-01

    @@ A low-temperature GaN (LT-GaN) nucleation layer is grown on a patterned sapphire substrate (PSS) using metal- organic chemical vapor deposition (MOCVD).The surface morphology of the LT-GaN is investigated and the selective nucleation phenomenon in the growth process of the LT-GaN nucleation layer is discovered.Meanwhile, effects of thickness of the LT-GaN and the annealing process on the phenomenon are also discussed.A pattern model is also proposed to analyze the possible mechanisms in atomic scale.

  17. Ultrahigh resolution optical coherence tomography with femtosecond Ti:sapphire laser and photonic crystal fiber

    Institute of Scientific and Technical Information of China (English)

    XUE Ping; James G FUJIMOTO

    2008-01-01

    Optical coherence tomography (OCT) with ultrahigh axial resolution was achieved by the super-contin- uum generated by coupling femtosecond pulses from a commercial Ti :sapphire laser into an air-silica microstructure fiber. The visible spectrum of the super-continuum from 450 to 700 nm centered at 540 nm can be generated. A free-space axial OCT resolution of 0.64 IJm was achieved. The sensitivity of OCT system was 108 dB with incident light power 3 mW at sample, only 7dB below the theoretical limit. Subcellular OCT imaging was also demonstrated, showing great potential for biomedical application.

  18. Analysis of tunable picosecond pulse generation from a distributed feedback Ti:sapphire laser

    Institute of Scientific and Technical Information of China (English)

    Hong Zhi; Yao Xiao-Ke

    2004-01-01

    A distributed feedback Ti:sapphire laser (DFTL) pumped by a 532nm Q-switched pulse is proposed for the generation of tunable picosecond pulses. With coupled rate equation model, the temporal characteristics of DFTL are obtained. The numerical solutions show that the DFTL pulse with a 50-ps pulse duration and as much as 3.SmJ pulse energy can be obtained under 40-m J, 5-ns pulse pumping. The dependence of output pulse width on the laser crystal's length, pumping pulse duration, and pumping rate is also discussed in detail.

  19. Sub-surface channels in sapphire made by ultraviolet picosecond laser irradiation and selective etching.

    Science.gov (United States)

    Moser, Rüdiger; Ojha, Nirdesh; Kunzer, Michael; Schwarz, Ulrich T

    2011-11-21

    We demonstrate the realization of sub-surface channels in sapphire prepared by ultraviolet picosecond laser irradiation and subsequent selective wet etching. By optimizing the pulse energy and the separation between individual laser pulses, an optimization of channel length can be achieved with an aspect ratio as high as 3200. Due to strong variation in channel length, further investigation was done to improve the reproducibility. By multiple irradiations the standard deviation of the channel length could be reduced to 2.2%. The achieved channel length together with the high reproducibility and the use of a commercial picosecond laser system makes the process attractive for industrial application.

  20. Containerless laser-induced flourescence study of vaporization and optical properties for sapphire and alumina

    Science.gov (United States)

    Nordine, Paul C.; Schiffman, Robert A.

    1988-01-01

    Evaporation of aluminum oxide was studied from 1800 to 2327 K by laser-induced flourescence (LIF) detection of Al atom vapor over sapphire and alumina spheres that were levitated in an argon gas jet and heated with a continuous wave CO2 laser. Optical properties were determined from apparent specimen temperatures measured with an optical pyrometer and true temperatures deduced from the LIF intensity versus temperature measurements using the known temperature dependence of the Al atom vapor concentration in equilibrium with Al2O3. The effects of impurities and dissolved oxygen on the high-temperature optical properties of aluminum oxide were discussed.

  1. Flashlamp-pumped Ti:Sapphire laser with different rods grown by Czochralski and Verneuil methods

    Science.gov (United States)

    Boquillon, J. P.; Said, J.

    1992-04-01

    The design and the development of a flashlamp-pumped Ti:Sapphire laser is described. Design criteria are discussed and performance improvements using different types of fluorescent UV converters or filters, such as organic dyes or doped glass are presented. We have tested different laser rods at various Ti-concentrations obtained by Verneuil or Czochralski growth techniques. The maximum laser output energy of 540 mJ with a differential efficiency up to 1% was achieved by using only a pyrex filter surrounding the laser rod.

  2. Measurement of Birefringence of Low-Loss, High-Reflectance Coating of M-Axis Sapphire

    OpenAIRE

    2001-01-01

    The birefringence of a low-loss, high-reflectance coating applied to an 8-cm-diameter sapphire crystal grown in the m-axis direction has been mapped. By monitoring the transmission of a high-finesse Fabry-Perot cavity as a function of the polarization of the input light, we find an upper limit for the magnitude of the birefringence of 2.5 x 10^-4 rad and an upper limit in the variation in direction of the birefringence of 10 deg. These values are sufficiently small to allow consideration of m...

  3. Synchronization of an Ultrafast Ti:Sapphire Laser to the S-Band Microwave

    Institute of Scientific and Technical Information of China (English)

    LIU Sheng-Guang; WANG Ming-Kai; SUN Da-Rui; DAI Jian-Ping; LI Yong-Gui

    2004-01-01

    @@ We have synchronized a 102-MHz ultrafast self-mode-locked Ti:sapphire laser to a 2856-MHz rf source with the sample-locking technology. The relative root-mean-square time-jitter is 0.57ps and the maximum time jitter is 2.60ps. This is the first time that synchronization between the ultrafast laser pulse and the s-band microwave has been accomplished in China. Potential applications include synchronization of lasers and rf power sources in particle accelerator experiments and high-resolution pump-probe experiments.

  4. All solid-state, injection-seeded Ti: sapphire ring laser

    Institute of Scientific and Technical Information of China (English)

    Ting Yu; Weibiao Chen; Jun Zhou; Jinzi Bi; Junwen Cui

    2005-01-01

    @@ In this letter, we present an all solid-state, injection-seeded Ti:sapphire laser. The laser is pumped by a laser diode pumped frequency-doubled Nd:YAG laser, and injection-seeded by an external cavity laser diode with the wavelength between 770 and 780 nm. The single longitude mode and the doubling efficiency of the laser are obtained after injection seeding. The experimental setup and relative results are reported.It is a good candidate laser source for mobile differential absorption lidar (DIAL) system.

  5. Homogenous Crack-Free Large Size YBCO/YSZ/Sapphire Films for Application

    Science.gov (United States)

    Almog, B.; Azoulay, M.; Deutscher, G.

    2006-09-01

    YBa2Cu3O7-δ (YBCO) films grown on Sapphire are highly suitable for applications. The production of large size (2-3″) homogeneous, thick (d ⩾ 600nm) films of high quality is of major importance. We report the growth of such films using a buffer layer of Yttrium-stabilized ZrO2(YSZ). The films are highly homogeneous and show excellent mechanical properties. They exhibit no sign of cracking even after many thermal cycles. Their critical thickness exceeds 1000nm. However, because of the large lattice mismatch there is a decrease in the electric properties(increases Rs, decreases jc).

  6. Parametric sensitivity and temporal dynamics of sapphire crystal growth via the micro-pulling-down method

    Science.gov (United States)

    Samanta, Gaurab; Yeckel, Andrew; Bourret-Courchesne, Edith D.; Derby, Jeffrey J.

    2012-11-01

    The micro-pulling-down (μ-PD) crystal growth of sapphire fibers, whose steady-state limits were the focus of our prior study [Samanta et al., Journal of Crystal Growth 335 (2011) 148-159], is further examined using a parametric sensitivity computation derived by linearizing the nonlinear model around a quasi-steady-state (QSS). In addition, transient analyses are performed to assess inherent stability and dynamic responses in this μ-PD system. Information from these two approaches enlarges our understanding of this particular process, and the approaches themselves are put forth as valuable complements to classical QSS analysis.

  7. Experimental deformation in sandstone, carbonates and quartz aggregate

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, Cecilia See Nga [Stony Brook Univ., NY (United States)

    2015-05-01

    The first part of my thesis is mainly focused on the effect of grain size distribution on compaction localization in porous sandstone. To identify the microstructural parameters that influence compaction band formation, I conducted a systematic study of mechanical deformation, failure mode and microstructural evolution in Bleurswiller and Boise sandstones, of similar porosity (~25%) and mineralogy but different sorting. Discrete compaction bands were observed to develop over a wide range of pressure in the Bleurswiller sandstone that has a relatively uniform grain size distribution. In contrast, compaction localization was not observed in the poorly sorted Boise sandstone. My results demonstrate that grain size distribution exerts important influence on compaction band development, in agreement with recently published data from Valley of Fire and Buckskin Gulch, as well as numerical studies. The second part aimed to improve current knowledge on inelastic behavior, failure mode and brittle-ductile transition in another sedimentary rock, porous carbonates. A micritic Tavel (porosity of ~13%) and an allochemical Indiana (~18%) limestones were deformed under compaction in wet and dry conditions. At lower confining pressures, shear localization occurred in brittle faulting regime. Through transitional regime, the deformation switched to cataclastic flow regime at higher confining pressure. Specifically in the cataclastic regime, the (dry and wet) Tavel and dry Indiana failed by distributed cataclastic flow, while in contrast, wet Indiana failed as compaction localization. My results demonstrate that different failure modes and mechanical behaviors under different deformation regimes and water saturation are fundamental prior to any geophysical application in porous carbonates. The third part aimed to focus on investigating compaction on quartz aggregate starting at low (MPa) using X-ray diffraction. We report the diffraction peak evolution of quartz with increasing

  8. Amplifier Module for 260-GHz Band Using Quartz Waveguide Transitions

    Science.gov (United States)

    Padmanabhan, Sharmila; Fung, King Man; Kangaslahti, Pekka P.; Peralta, Alejandro; Soria, Mary M.; Pukala, David M.; Sin, Seth; Samoska, Lorene A.; Sarkozy, Stephen; Lai, Richard

    2012-01-01

    Packaging of MMIC LNA (monolithic microwave integrated circuit low-noise amplifier) chips at frequencies over 200 GHz has always been problematic due to the high loss in the transition between the MMIC chip and the waveguide medium in which the chip will typically be used. In addition, above 200 GHz, wire-bond inductance between the LNA and the waveguide can severely limit the RF matching and bandwidth of the final waveguide amplifier module. This work resulted in the development of a low-loss quartz waveguide transition that includes a capacitive transmission line between the MMIC and the waveguide probe element. This capacitive transmission line tunes out the wirebond inductance (where the wire-bond is required to bond between the MMIC and the probe element). This inductance can severely limit the RF matching and bandwidth of the final waveguide amplifier module. The amplifier module consists of a quartz E-plane waveguide probe transition, a short capacitive tuning element, a short wire-bond to the MMIC, and the MMIC LNA. The output structure is similar, with a short wire-bond at the output of the MMIC, a quartz E-plane waveguide probe transition, and the output waveguide. The quartz probe element is made of 3-mil quartz, which is the thinnest commercially available material. The waveguide band used is WR4, from 170 to 260 GHz. This new transition and block design is an improvement over prior art because it provides for better RF matching, and will likely yield lower loss and better noise figure. The development of high-performance, low-noise amplifiers in the 180-to- 700-GHz range has applications for future earth science and planetary instruments with low power and volume, and astrophysics array instruments for molecular spectroscopy. This frequency band, while suitable for homeland security and commercial applications (such as millimeter-wave imaging, hidden weapons detection, crowd scanning, airport security, and communications), also has applications to

  9. Mineralogy, morphology, and textural relationships in coatings on quartz grains in sediments in a quartz-sand aquifer.

    Science.gov (United States)

    Zhang, Shouliang; Kent, Douglas B; Elbert, David C; Shi, Zhi; Davis, James A; Veblen, David R

    2011-06-01

    Mineralogical studies of coatings on quartz grains and bulk sediments from an aquifer on Western Cape Cod, Massachusetts, USA were carried out using a variety of transmission electron microscopy (TEM) techniques. Previous studies demonstrated that coatings on quartz grains control the adsorption properties of these sediments. Samples for TEM characterization were made by a gentle mechanical grinding method and focused ion beam (FIB) milling. The former method can make abundant electron-transparent coating assemblages for comprehensive and quantitative X-ray analysis and the latter technique protects the coating texture from being destroyed. Characterization of the samples from both a pristine area and an area heavily impacted by wastewater discharge shows similar coating textures and chemical compositions. Major constituents of the coating include Al-substituted goethite and illite/chlorite clays. Goethite is aggregated into well-crystallized domains through oriented attachment resulting in increased porosity. Illite/chlorite clays with various chemical compositions were observed to be mixed with goethite aggregates and aligned sub-parallel to the associated quartz surface. The uniform spatial distribution of wastewater-derived phosphorus throughout the coating from the wastewater-contaminated site suggests that all of the coating constituents, including those adjacent to the quartz surface, are accessible to groundwater solutes. Both TEM characterization and chemical extraction results indicate there is a significantly greater amount of amorphous iron oxide in samples from wastewater discharge area compared to those from the pristine region, which might reflect the impact of redox cycling of iron under the wastewater-discharge area. Coating compositions are consistent with the moderate metal and oxy-metalloid adsorption capacities, low but significant cation exchange capacities, and control of iron(III) solubility by goethite observed in reactive transport

  10. Carbon in intimate contact with quartz reduces the biological activity of crystalline silica dusts.

    Science.gov (United States)

    Ghiazza, Mara; Tomatis, Maura; Doublier, Sophie; Grendene, Francesca; Gazzano, Elena; Ghigo, Dario; Fubini, Bice

    2013-01-18

    To evaluate the effect of carbonaceous materials on the pathogenic activity of quartz dusts, mixtures of carbon soot (1 and 10%) and quartz (Min-U-Sil) were prepared and then milled so to attain an intimate association of carbon and the quartz surface. Both cellular and cell-free tests show that carbon associated to quartz completely inhibits the typical free radical generation of quartz dusts (through Fenton activity and homolytic cleavage of a C-H bond) and suppresses the oxidative stress and inflammation induced by quartz alone on MH-S murine macrophage cells (lipid peroxidation, nitric oxide release, and tumor necrosis factor-α synthesis). The cytotoxic response to quartz is also largely reduced. An extremely pure quartz milled with 10% of soot showed inactivating effects on the adverse reactions to quartz similar to Min-U-Sil quartz. None of these effects takes place when the same experiments are carried out with mechanically mixed samples, which suggests that carbon acts not just as a radical quencher but because of its association to the quartz surface.

  11. Raman Spectrum Study on Quartz Exsolution in Omphacite of Eclogite and Its Tectonic Significances

    Institute of Scientific and Technical Information of China (English)

    Wang Lu; Jin Zhenmin; He Mouchun

    2003-01-01

    The studies on ultra-microstructure characteristics of quartz exsolution in eclogite and coesite in UHP eclogite of several localities are done with the appliance of laser Raman spectroscopy and Ustage. Research results show that the phase transformation of coesite-quartz in garnet and/or omphacite is a continuous process. Topological relationship is present between quartz exsolution in omphacite and its host mineral which shows orientations of two long axes of quartz exsolution parallel to (100) and (-101) of omphacite. At present, some scholars suggest that the quartz exsolution in omphacite of eclogite is the evidence of UHP metamorphism. However, temperature and pressure condition and the exsolution mechanism of oriented needlelike quartz in omphacite still remain unclear. Therefore, further study should be enhanced on experimental research on exsolution mechanism of super-silicate clinopyroxene, which could provide experimental quantitative constraint on quartz exsolution as UHP indicator.

  12. The effect of quartz on the flotation of pyrite depressed by serpentine

    Directory of Open Access Journals (Sweden)

    Bo Feng

    2015-01-01

    Full Text Available The effect of quartz particles on the flotation of pyrite depressed by serpentine has been investigated through flotation tests, adsorption tests, zeta potential measurements and DLVO calculation. The results show that the presence of hydrophilic serpentine slimes on pyrite surface reduces collector adsorption and results in lower recovery of pyrite. The finer the serpentine slime is, the lower the pyrite recovery will be. Quartz particles do not interfere with pyrite flotation. However, the addition of quartz particles increases the adsorption of collector on pyrite surface and limits the detrimental effect of serpentine on pyrite flotation. The fine-grained quartz is more effective. Zeta potential measurements and DLVO calculation illustrate that the zeta potential of quartz is more negative than that of pyrite and the attraction force between serpentine and quartz is stronger than force between serpentine and pyrite, thus some serpentine slimes were transferred from pyrite surface to quartz in the process of attrition.

  13. Growth of planar semipolar GaN via epitaxial lateral overgrowth on pre-patterned sapphire substrate

    Energy Technology Data Exchange (ETDEWEB)

    Schwaiger, Stephan; Argut, Ilona; Wunderer, Thomas; Lipski, Frank; Roesch, Rudolf; Scholz, Ferdinand [Institute of Optoelectronics, University of Ulm (Germany)

    2010-07-01

    We report on the growth of planar semipolar GaN on pre-patterned sapphire substrates via metalorganic vapor phase epitaxy. The sapphire templates were structured with grooves perpendicular to the c-direction of the crystal. Using appropriate growth parameters semipolar GaN can be grown from the c-plane like sidewall of the patterned sapphire, resulting in a flat and planar semipolar surface. Hence, this method allows the growth of semipolar GaN on large areas. Scanning electron, transmission electron and atomic force microscopy measurements show an atomically flat surface. Photoluminescence spectroscopy spectra show the high quality of the material since the spectra are dominated by the near band edge emission but still exhibit some defect related contributions. Furthermore high resolution X-ray diffraction rocking curve measurements result in small full widths at half maximum of less than 400 arcsec for both, the symmetrical reflection and the asymmetrical (0002) reflection.

  14. Crystal front shape control by use of an additional heater in a Czochralski sapphire single crystal growth system

    Science.gov (United States)

    Hur, Min-Jae; Han, Xue-Feng; Choi, Ho-Gil; Yi, Kyung-Woo

    2017-09-01

    The quality of sapphire single crystals used as substrates for LED production is largely influenced by two defects: dislocation density and bubbles trapped in the crystal. In particular, the dislocation density has a higher value in sapphire grown by the Czochralski (CZ) method than by other methods. In the present study, we predict a decreased value for the convexity and thermal gradient at the crystal front (CF) through the use of an additional heater in an induction-heated CZ system. In addition, we develop a solute concentration model by which the location of bubble formation in CZ growth is calculated, and the results are compared with experimental results. We further calculate the location of bubble entrapment corresponding with the use of an additional heater. We find that sapphire crystal growth with an additional heater yields a decreased thermal gradient at the CF, together with decreased CF convexity, improved energy efficiency, and improvements in terms of bubble formation location.

  15. Multimode interference and a white light scanning Michelson interferometer with a 400-mm sapphire fiber sensing head

    Science.gov (United States)

    Li, Tianchu; May, Russell G.; Wang, Anbo; Claus, Richard O.

    1998-08-01

    In this paper we present the analysis of multimode (MM) interference induced by MM fiber interferometers and report the development of a white light scanning fiber Michelson interferometer with a sapphire fiber sensing head for the measurement of position-distance at high temperatures. The 'mode fading' effect in standard graded 50/125 micrometers fiber and independent 'inter-mode interference' in 100 micrometers step index profile fiber are discussed. By means of the 'mode selecting' technique, proposed and developed in this work, we demonstrated white light fringes with signal to noise ratios of more than 12 with a sensing head composed of a 400 mm long lead sapphire fiber and an uncoated sapphire target fiber.

  16. Antibody-forming cells and serum hemolysin responses of pastel and sapphire mink inoculated with Aleutian disease virus.

    Science.gov (United States)

    Lodmell, D L; Bergman, R K; Hadlow, W J

    1973-11-01

    The effect of Aleutian disease virus (ADV) on serum hemolysin titers and antibody-forming cells in lymph nodes and spleens of sapphire and pastel mink inoculated with goat erythrocytes (G-RBC) was investigated. ADV injected 1 day after primary antigenic stimulation with G-RBC did not depress the immune responses of either color phase for a period of 26 days. However, when G-RBC were injected 47 days after ADV, both the number of antibody-forming cells and hemolysin titers were more markedly depressed in sapphire than in pastel mink. The results are discussed in relation to the greater susceptibility of sapphire mink and the variable susceptibility of pastel mink to the Pullman isolate of ADV.

  17. Transmission Electron Microscopy (TEM) Sample Preparation of Si(1-x)Gex in c-Plane Sapphire Substrate

    Science.gov (United States)

    Kim, Hyun Jung; Choi, Sang H.; Bae, Hyung-Bin; Lee, Tae Woo

    2012-01-01

    The National Aeronautics and Space Administration-invented X-ray diffraction (XRD) methods, including the total defect density measurement method and the spatial wafer mapping method, have confirmed super hetero epitaxy growth for rhombohedral single crystalline silicon germanium (Si1-xGex) on a c-plane sapphire substrate. However, the XRD method cannot observe the surface morphology or roughness because of the method s limited resolution. Therefore the authors used transmission electron microscopy (TEM) with samples prepared in two ways, the focused ion beam (FIB) method and the tripod method to study the structure between Si1-xGex and sapphire substrate and Si1?xGex itself. The sample preparation for TEM should be as fast as possible so that the sample should contain few or no artifacts induced by the preparation. The standard sample preparation method of mechanical polishing often requires a relatively long ion milling time (several hours), which increases the probability of inducing defects into the sample. The TEM sampling of the Si1-xGex on sapphire is also difficult because of the sapphire s high hardness and mechanical instability. The FIB method and the tripod method eliminate both problems when performing a cross-section TEM sampling of Si1-xGex on c-plane sapphire, which shows the surface morphology, the interface between film and substrate, and the crystal structure of the film. This paper explains the FIB sampling method and the tripod sampling method, and why sampling Si1-xGex, on a sapphire substrate with TEM, is necessary.

  18. The frequency-dependent AC photoresistance behavior of ZnO thin films grown on different sapphire substrates.

    Science.gov (United States)

    Cholula-Díaz, Jorge L; Barzola-Quiquia, José; Videa, Marcelo; Yin, Chunhai; Esquinazi, Pablo

    2017-09-13

    Zinc oxide (ZnO) thin films were grown by pulsed layer deposition under an N2 atmosphere at low pressures on a- and r-plane sapphire substrates. Structural studies using X-ray diffraction confirmed that all films had a wurtzite phase. ZnO thin films on a- and r-plane sapphire have grown with orientations along the [0002] and [112[combining macron]0] directions, respectively. Room temperature photoluminescence measurements indicate that the presence of native point defects (interstitial zinc, oxygen vacancies, oxygen antisites and zinc vacancies) is more preponderant for ZnO thin films grown on the r-plane sapphire substrate than the sample grown on the a-plane sapphire substrate. Room temperature impedance spectroscopy measurements were performed in an alternating current frequency range from 40 to 10(5) Hz in the dark and under normal light. An unusual positive photoresistance effect is observed at frequencies above 100 kHz, which we suggest to be due to intrinsic defects present in the ZnO thin films. Furthermore, an analysis of the optical time response revealed that the film grown on the r-plane sapphire substrate responds faster (characteristic relaxation times for τ1, τ2 and τ3 of 0.05, 0.26 and 6.00 min, respectively) than the film grown on the a-plane sapphire substrate (characteristic relaxation times for τ1, τ2 and τ3 of 0.10, 0.73 and 4.02 min, respectively).

  19. Influence of Cr and W alloying on the fiber-matrix interfacial shear strength in cast and directionally solidified sapphire NiAl composites

    Science.gov (United States)

    Asthana, R.; Tiwari, R.; Tewari, S. N.

    1995-01-01

    Sapphire-reinforced NiAl matrix composites with chromium or tungsten as alloying additions were synthesized using casting and zone directional solidification (DS) techniques and characterized by a fiber pushout test as well as by microhardness measurements. The sapphire-NiAl(Cr) specimens exhibited an interlayer of Cr rich eutectic at the fiber-matrix interface and a higher interfacial shear strength compared to unalloyed sapphire-NiAl specimens processed under identical conditions. In contrast, the sapphire-NiAl(W) specimens did not show interfacial excess of tungsten rich phases, although the interfacial shear strength was high and comparable to that of sapphire-NiAl(Cr). The postdebond sliding stress was higher in sapphire-NiAl(Cr) than in sapphire-NiAl(W) due to interface enrichment with chromium particles. The matrix microhardness progressively decreased with increasing distance from the interface in both DS NiAl and NiAl(Cr) specimens. The study highlights the potential of casting and DS techniques to improve the toughness and strength of NiAl by designing dual-phase microstructures in NiAl alloys reinforced with sapphire fibers.

  20. Generation of 7-fs laser pulse directly from a compact Ti:sapphire laser with chirped mirrors

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A compact femtosecond Ti:sapphire laser resonator consisting of three chirped mirrors and one output coupler was designed. By accurately balancing the intra- cavity dispersions between Ti:sapphire crystal, air and chirped mirrors, we directly generated the laser pulse shorter than 7 fs at the average power of 340 mW with 3.1 W pump. The repetition rate of the laser oscillator is 173 MHz at the centre wavelength of 791 nm, and the ultrabroaden spectrum covers from 600 nm to 1000 nm. To the best of our knowledge, this is the simplest laser resonator capable of generating sub-10 fs laser pulse.

  1. An investigation of structural properties of GaN films grown on patterned sapphire substrates by MOVPE

    Science.gov (United States)

    Törmä, P. T.; Ali, M.; Svensk, O.; Sintonen, S.; Kostamo, P.; Suihkonen, S.; Sopanen, M.; Lipsanen, H.; Odnoblyudov, M. A.; Bougrov, V. E.

    2009-12-01

    GaN films were fabricated by metal organic vapor phase epitaxy (MOVPE) on patterned sapphire substrates (PSSs) with either direct or inverse type patterned structures. Both of these two types of PSSs had their own unique GaN growth process which depart from the standard growth on the planar c-plane. GaN films on PSSs showed decreased threading dislocation (TD) density. However, differences between the crystal quality of the GaN films grown on PSSs were observed. It was also found out with one of the pattern type that the TD density varied laterally and followed the periodicity of the pattern on the sapphire surface.

  2. Generation of 7-fs laser pulse directly from a compact Ti:sapphire laser with chirped mirrors

    Institute of Scientific and Technical Information of China (English)

    ZHAO YanYing; WANG Peng; ZHANG Wei; TIAN JinRong; WEI ZhiYi

    2007-01-01

    A compact femtosecond Ti:sapphire laser resonator consisting of three chirped mirrors and one output coupler was designed. By accurately balancing the intracavity dispersions between Ti:sapphire crystal, air and chirped mirrors, we directly generated the laser pulse shorter than 7 fs at the average power of 340 mW with 3.1 W pump. The repetition rate of the laser oscillator is 173 MHz at the centre wavelength of 791 nm, and the ultrabroaden spectrum covers from 600 nm to 1000 nm. To the best of our knowledge, this is the simplest laser resonator capable of generating sub-10 fs laser pulse.

  3. Synthesis of Calcium Silicate (Casio3 Using Calcium Fluoride, Quartz and Microbes

    Directory of Open Access Journals (Sweden)

    B. Gopal Krishna

    2015-09-01

    Full Text Available Microbes like bacteria, algae, fungi and virus play an important role to catalyst chemical reactions. In Nature, ores or minerals of different compounds are formed due to microbial environment and other factors like weathering. Microbial environment is also instrumental in forming calcium containing silicate minerals. Chemical reactions occur under microbial environment because microbes have the ability to control or modify different factors like pH, chemical potential and temperature during reactions. In this paper, synthesis of calcium silicate (CaSiO3 using calcium fluoride (CaF2 and quartz (SiO2 under microbial environment in a laboratory is being adopted to produce the required material. XRD technique is used to confirm the formation of CaSiO3.

  4. Demonstrating the feasibility of heat extraction through sapphire fibers for the GW observatory KAGRA

    CERN Document Server

    Khalaidovski, Alexander; Chen, Dan; Komma, Julius; Schwarz, Christian; Tokoku, Chihiro; Kimura, Nobuhiro; Suzuki, Toshikazu; Scheie, Alan O; Majorana, Ettore; Nawrodt, Ronny; Yamamoto, Kazuhiro

    2014-01-01

    Currently, the Japanese gravitational wave laser interferometer KAGRA is under construction in the Kamioka observatory. As one main feature, it will employ sapphire mirrors operated at a temperature of 20K to reduce the impact from thermal noise and suspended from multi-stage pendulums to reduce seismic noise. Thus the heat load deposited in the mirrors by absorption of the circulating laser light as well as originating from thermal radiation will need to be extracted through the last suspension stage. This stage will consist of four thin sapphire fibers with larger heads necessary to connect the fibers to both the mirror and the upper stage. In this paper, we discuss heat conductivity measurements on different fiber candidates. While all fibers had a diameter of 1.6mm, different surface treatments and approaches to attach the heads were analyzed. Our measurements show that fibers fulfilling the basic KAGRA heat conductivity requirement of $\\kappa\\geq\\,$5000 W/m/K at 20K are technologically feasible.

  5. Design and construction of a tunable pulsed Ti:sapphire laser

    Science.gov (United States)

    Panahi, Omid; Nazeri, Majid; Tavassoli, Seyed Hassan

    2015-02-01

    In this paper, design and constr uction of a tunable pulsed Ti:sapphire laser and numerical solution of the corresponding rate equations are reported. Rate equations for a four-level system are written and their numerical solution is examined. Furthermore, an optical setup is introduced. In this setup, a Ti:sapphire crystal is longitudinally pumped by the second harmonics of a Q-Switched Nd:YAG laser, and a prism is used as a wavelength-selective element as well. This setup is established for two 10 and 50 % transmission output couplers. In case of using the 10 % coupler, the output energy of the laser, for the pump energy of 36 mJ, is pulses with 3.5 mJ energy and for the 50 % coupler, with 50 mJ of pump energy, pulses with 10 mJ energy are generated. A wavelength tuning range of more than 160 nm is possible. The repetition rate of this laser is 10 Hz and the temporal duration of the pulses is about 30 ns.

  6. A scalable pathway to nanostructured sapphire optical fiber for evanescent-field sensing and beyond

    Science.gov (United States)

    Chen, Hui; Tian, Fei; Kanka, Jiri; Du, Henry

    2015-03-01

    We here report an innovative and scalable strategy of transforming a commercial unclad sapphire optical fiber to an all-alumina nanostructured sapphire optical fiber (NSOF). The strategy entails fiber coating with metal aluminum followed by anodization to form alumina cladding of highly organized pore channel structure. Through experiments and numerical simulation, we demonstrate the utility and benefit of NSOF, analogous to all-silica microstructured optical fiber, for evanescent-field surface-enhanced Raman scattering (SERS) measurements. We experimentally reveal the feasibility of Ag nanoparticles (NPs)-enabled NSOF SERS sensing of 10-6 M Rhodamine 6G (R6G) after thermal treatment at 500 °C for 6 h by taking advantage of porous anodic aluminum oxide (AAO) structure to stabilize the Ag NPs. We show, via numerical simulations, that AAO cladding significantly increases the evanescent-field overlap, lower porosity of AAO results in higher evanescent-field overlap, and optimized AAO nanostructure yields greater SERS enhancement.

  7. Tunable integrated optical filters based on sapphire microspheres and liquid crystals

    Science.gov (United States)

    Gilardi, Giovanni; Yilmaz, Hasan; Sharif Murib, Mohammed; Asquini, Rita; d'Alessandro, Antonio; Serpengüzel, Ali; Beccherelli, Romeo

    2010-05-01

    We present an integrated optical narrowband electrically tunable filter based on the whispering gallery modes of sapphire microspheres and double ion-exchanged channel BK7 glass waveguides. Tuning is provided by a liquid crystal infiltrated between the spheres and the glass substrate. By suitably choosing the radii of the spheres and of the circular apertures, upon which the spheres are positioned, arrays of different filters can be realized on the same substrate with a low cost industrial process. We evaluate the performance in terms of quality factor, mode spacing, and tuning range by comparing the numerical results obtained by the numerical finite element modeling approach and with the analytical approach of the Generalized Lorenz-Mie Theory for various design parameters. By reorienting the LC in an external electrical field, we demonstrate the tuning of the spectral response of the sapphire microsphere based filter. We find that the value of the mode spacing remains nearly unchanged for the different values of the applied electric field. An increase of the applied electric field strength, changes the refractive index of the liquid crystal, so that for a fixed geometry the mode spacing remains unchanged.

  8. The Structure of Sapphire Implanted with Carbon at Room Temperature and 1000° C

    Science.gov (United States)

    Alves, E.; Marques, C.; Safran, G.; McHargue, Carl J.

    2009-03-01

    Carbon was implanted into sapphire at various temperatures as part of a study of the different defect structures produced by a series of light ions. Implantations were made with 150 keV ions to fluences of 1×1016 and 1×1017ions/cm2 at room temperature (RT) and 1000° C. The defect structures were characterized using Rutherford backscattering-channeling (RBS-C) and transmission electron microscopy (TEM). The RBS-C spectra indicated low residual disorder for RT implantation at 1×1016 C+/cm2. The de-channeling approached the random value at 1×1017 C+/cm2 and the TEM examination revealed a buried amorphous layer containing embedded sapphire nanocrystals. Damaged layers containing planar defects generally aligned parallel to the surface surrounded this layer. The RBS-C spectra for the sample implanted at 1000° C with 1×1017C+/cm2 suggested a highly damaged but crystalline surface that was confirmed by TEM micrographs.

  9. Study of the defects in GaN epitaxial films grown on sapphire by HVPE

    Science.gov (United States)

    Liu, Zhanhui; Xiu, Xiangqian; Chen, Lin; Zhang, Rong; Xie, Zili; Han, Ping; Shi, Yi; Gu, Shulin; Zheng, Youdou

    2008-02-01

    In this paper, the defects in hexagonal GaN epitaxial layers grown on (0001) sapphire (Al IIO 3) substrates by HVPE with a horizontal tube reactor had been studied. The GaN epitaxial layers were etched by means of defect-selective etching (Orthodox etching in molten KOH). The samples were characterized by Scanning Electron Microscopy (SEM) and Cathodoluminescence spectra (CL). From surface morphology and cross-sectional images, the defects could be divided into various types: cracks, low angle grain boundary (LAGB), nano-pipes and dislocations. These different defects were discussed. The cracks were proposed as related to the strain. And the strain could not only come from the lattice mismatch and thermal mismatch between sapphire and GaN layer in their interface, but also from the HVPE growth process. It was found that these screw, mixed and edge type dislocations formed small hexagonal pits after etching. Some pits would be observed in the area near LAGB. Additionally, by CL mapping technique, some non-radiative recombination centers without surface terminations could be probed optically.

  10. Gold wetting effects on sapphire irradiated with GeV uranium ions

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, S.M.M. [Universite Claude Bernard, Villeurbanne (France). Dept. de Phys. des Mater.; Canut, B. [Universite Claude Bernard, Villeurbanne (France). Dept. de Phys. des Mater.; Fornazero, J. [Universite Claude Bernard, Villeurbanne (France). Dept. de Phys. des Mater.; Thevenard, P. [Universite Claude Bernard, Villeurbanne (France). Dept. de Phys. des Mater.; Toulemonde, M. [Centre Interdisciplinaire de Recherche avec les Ions Lourds (CIRIL), Boulevard A. Becquerel, 14040 Caen Cedex (France)

    1997-02-01

    Single crystals of {alpha}-Al{sub 2}O{sub 3} were irradiated with {sup 238}U ions using two different energies: 3.4 MeV/u and 1.7 MeV/u. The irradiations were performed at a temperature of {approx}80 K, with fluences ranging from 1.2 x 10{sup 12} to 2.5 x 10{sup 12} ions cm{sup -2}. After irradiation, thin gold films were deposited on the sapphire surfaces by using a sputtering method. Subsequent annealing in air at a temperature of 723 and 923 K were applied to investigate the influence of the pre-damage on the adhesion of the gold layer on the sapphire surface. Rutherford backscattering analysis and scanning electron microscopy performed in both virgin and irradiated areas, show that the pre-irradiation damage inhibits the gold film of breaking up into islands after annealing. A wetting effect, which could depend on the damage morphology, is clearly observed. (orig.).

  11. Ultra stable and very low noise signal source using a cryocooled sapphire oscillator for VLBI

    CERN Document Server

    Nand, Nitin R; Ivanov, Eugene N; Santarelli, Giorgio

    2011-01-01

    Here we present the design and implementation of a novel frequency synthesizer based on low phase noise digital dividers and a direct digital synthesizer. The synthesis produces two low noise accurate and tunable signals at 10 MHz and 100 MHz. We report on the measured residual phase noise and frequency stability of the synthesizer, and estimate the total frequency stability, which can be expected from the synthesizer seeded with a signal near 11.2 GHz from an ultra-stable cryocooled sapphire oscillator. The synthesizer residual single sideband phase noise, at 1 Hz offset, on 10 MHz and 100 MHz signals, respectively, were measured to be -135 dBc/Hz and -130 dBc/Hz. Their intrinsic frequency stability contributions, on the 10 MHz and 100 MHz signals, respectively, were measured as sigma_y = 9 x 10^-15 and sigma_y = 2.2 x 10^-15, at 1 s integration time. The Allan Deviation of the total fractional frequency noise on the 10 MHz and 100 MHz signals derived from the synthesizer with the cryocooled sapphire oscilla...

  12. DC-powered Fe3+:sapphire Maser and its Sensitivity to Ultraviolet Light

    CERN Document Server

    Oxborrow, Mark; Kersalé, Yann; Giordano, Vincent

    2010-01-01

    The zero-field Fe3+:sapphire whispering-gallery-mode maser oscillator exhibits several alluring features: Its output is many orders of magnitude brighter than that of an active hydrogen maser and thus far less degraded by spontaneous-emission (Schawlow-Townes) and/or receiving-amplifier noise. Its oscillator loop is confined to a piece of mono-crystalline rock bolted into a metal can. Its quiet amplification combined with high resonator Q provide the ingredients for exceptionally low phase noise. We here concentrate on novelties addressing the fundamental conundrums and technical challenges that impede progress. (1) Roasting: The "mase-ability" of sapphire depends significantly on the chemical conditions under which it is grown and heat-treated. We provide some fresh details and nuances here. (2) Simplification: This paper obviates the need for a Ka-band synthesizer: it describes how a 31.3 GHz loop oscillator, operating on the preferred WG pump mode, incorporating Pound locking, was built from low-cost compo...

  13. Characteristics and kinetics of laser-pumped Ti:Sapphire oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Eggleston, J.M.; De Shazer, L.G.; Kangas, K.W.

    1988-06-01

    The experimental performance of a gain-switched Ti:Sapphire laser oscillator pumped by a frequency-doubled Q-switched Nd:YAG laser system is presented for a variety of operating conditions. A theoretical model developed for this oscillator predicts well its performance. In particular, the observed curved input-output energy plots for the oscillator result from the kinetics of gain switching and fluorescence decay during the gain buildup period. Fluorescence decay also produces observed oscillator thresholds higher than those normally predicted by the standard gain-equals-loss condition. Gain-switched parasitic modes, with a higher threshold but shorter roundtrip time than the resonator mode, cause the resonator mode to oscillate only over a finite range of pump energies. Also, spectroscopic investigations show that the Ti:Sapphire cross-section spectrum is well fit by a Poisson distribution, giving a peak cross section of 3 x 10/sup -19/ cm/sup 2/ for the ..pi.. polarization.

  14. A microfabricated sun sensor using GaN-on-sapphire ultraviolet photodetector arrays

    Science.gov (United States)

    Miller, Ruth A.; So, Hongyun; Chiamori, Heather C.; Suria, Ateeq J.; Chapin, Caitlin A.; Senesky, Debbie G.

    2016-09-01

    A miniature sensor for detecting the orientation of incident ultraviolet light was microfabricated using gallium nitride (GaN)-on-sapphire substrates and semi-transparent interdigitated gold electrodes for sun sensing applications. The individual metal-semiconductor-metal photodetector elements were shown to have a stable and repeatable response with a high sensitivity (photocurrent-to-dark current ratio (PDCR) = 2.4 at -1 V bias) and a high responsivity (3200 A/W at -1 V bias) under ultraviolet (365 nm) illumination. The 3 × 3 GaN-on-sapphire ultraviolet photodetector array was integrated with a gold aperture to realize a miniature sun sensor (1.35 mm × 1.35 mm) capable of determining incident light angles with a ±45° field of view. Using a simple comparative figure of merit algorithm, measurement of incident light angles of 0° and 45° was quantitatively and qualitatively (visually) demonstrated by the sun sensor, supporting the use of GaN-based sun sensors for orientation, navigation, and tracking of the sun within the harsh environment of space.

  15. Tunable Single-Frequency Intracavity Frequency-Doubled Ti:Sapphire Laser around 461 nm

    Institute of Scientific and Technical Information of China (English)

    李凤琴; 石柱; 李永民; 彭堃墀

    2011-01-01

    We demonstrate a tunable continuous-wave single frequency intracavity frequency-doubled Ti:sapphire laser.The highest output power of 280mW at 461.62nm is obtained by employing a type-I phase-matched BIBO crystal and the peak-to-peak fluctuation of the power is less than ±1% within three hours.The frequency stability is better than ±2.22 MHz over 10min when the laser is locked to a confocal Fabry-Perot cavity.A three-plate birefringent filter allows for the tunable range from 457nm to 467nm,which covers the absorption line of the strontium atoms(460.86nm).%We demonstrate a tunable continuous-wave single frequency intracavity frequency-doubled Ti:sapphire laser. The highest output power of 280mW at 461.62nm is obtained by employing a type-I phase-matched BIBO crystal and the peak-to-peak fluctuation of the power is less than ±1% within three hours. The frequency stability is better than ±2.22MHz over lOmin when the laser is locked to a confocal Fabry-Perot cavity. A three-plate birefringent filter allows for the tunable range from 457nm to 467 nm, which covers the absorption line of the strontium atoms (460.86 nm).

  16. First-principles molecular dynamics simulations of NH4(+) and CH3COO(-) adsorption at the aqueous quartz interface.

    Science.gov (United States)

    Wright, Louise B; Walsh, Tiffany R

    2012-12-14

    The ability to exert molecular-level control at the aqueous interface between biomolecules and inorganic substrates is pivotal to advancing applications ranging from sustainable manufacturing to targeted therapeutics. Progress is hindered by a lack of structural information of these interfaces with atomic resolution. Molecular simulation is one approach to obtain such data, but can be limited by the reliability of the force-field used. First-principles simulations, in principle, can provide insights into such aqueous interfaces, but are resource-intensive, limiting previous first-principles studies to approximate the environment of liquid water. Here, we use Car-Parrinello simulations to investigate adsorption of two charged adsorbates that are functional groups common to all amino-acids--ethanoate and ammonium--at the interface between hydroxylated quartz and liquid water, directly incorporating full solvation effects at the interface. Our findings reveal the stable character of carboxylate-quartz binding, as well as the surprisingly indifferent nature of ammonium-quartz interactions, in liquid water.

  17. Recrystallization of quartz after low-temperature plasticity - The record of stress relaxation below the seismogenic zone

    Science.gov (United States)

    Trepmann, Claudia A.; Hsu, Chen; Hentschel, Felix; Döhler, Katharina; Schneider, Christian; Wichmann, Veronica

    2017-02-01

    Quartz microfabrics in rocks from the Silvretta basal thrust and the Defereggen-Antholz-Vals (DAV) shear zone in the Eastern Alps, are analysed by polarized light and electron microscopy. The microfabrics from both shear zones record a switch from low-temperature plasticity at transient high stress to recrystallization at relaxing stresses at greenschist facies conditions. The development of new grains is dominantly by subgrain rotation and subsequent strain-induced grain-boundary migration in areas of localized high strain developed during initial low-temperature plasticity. The findings suggest that new grains develop at almost random crystallographic orientations at fast rates of stress relaxation (i.e. at low stress), as indicated by recrystallized quartz zones in the Silvretta fault rocks. In contrast, at slow rates of stress relaxation, new grains develop at moderately high stresses with crystallographic preferred orientation characterized by high Schmid factor for basal glide, as indicated by vein quartz samples from the DAV shear zone. Both recorded histories with transient peak stresses and different rates of stress relaxation are interpreted to be related to seismic activity of the fault systems. This study demonstrates that characteristic microfabrics provide important information about the deformation history of natural shear zones developed in different tectonic regimes.

  18. Investigating quartz optically stimulated luminescence dose-response curves at high doses

    Energy Technology Data Exchange (ETDEWEB)

    Lowick, Sally E., E-mail: lowick@geo.unibe.c [Institut fuer Geologie, Universitaet Bern, Baltzerstrasse 1-3, 3012 Bern (Switzerland); Preusser, Frank [Institut fuer Geologie, Universitaet Bern, Baltzerstrasse 1-3, 3012 Bern (Switzerland); Wintle, Ann G. [Institute of Geography and Earth Sciences, Aberystwyth University, AberystwythSY23 3DB (United Kingdom)

    2010-10-15

    Despite the general expectation that optically stimulated luminescence (OSL) growth should be described by a simple saturating exponential function, an additional high dose component is often reported in the dose response of quartz. Although often reported as linear, it appears that this response is the early expression of a second saturating exponential. While some studies using equivalent doses that fall in this high dose region have produced ages that correlate well with independent dating, others report that it results in unreliable age determinations. Two fine grain sedimentary quartz samples that display such a response were used to investigate the origin of this additional high dose component: three experiments were conducted to examine their dose-response up to >1000 Gy. The high dose rates provided by laboratory irradiation were found not to induce a sensitivity change in the response to a subsequent test dose, with the latter not being significantly different from those generated following naturally acquired doses. The relative percentage contributions of the fast and medium OSL components remained fixed throughout the dose-response curve, suggesting that the electron traps that give rise to the initial OSL do not change with dose. An attempt was made to investigate a change in luminescence centre recombination probability by monitoring the depletion of the '325 {sup o}C' thermoluminescence (TL) during the optical stimulation that would result in depletion of the OSL signal. The emissions measured through both the conventional ultraviolet (UV), and a longer wavelength violet/blue (VB) window, displayed similar relative growth with dose, although it was not possible to resolve the origin of the VB emissions. No evidence was found to indicate whether the additional component at high doses occurs naturally or is a product of laboratory treatment. However, it appears that these samples display an increased sensitivity of quartz OSL to high doses

  19. Graphite and quartz petrofabrics: Examples from the Ediacaran black quartzites of the Ossa-Morena Zone (SW Iberia)

    Science.gov (United States)

    Puelles, P.; Ábalos, B.; Fernández-Armas, S.

    2014-03-01

    We study with the Electron Back-Scattered Diffraction (EBSD) technique the fabric of metamorphosed and ductilely deformed phtanites or graphitic cherts, a common lithotype in Ediacaran supracrustals of the west European Cadomian orogen. Currently they are black quartzites with a planolinear tectonite structure. Microscopically they present a sub-mm-scale alternation of coarse- and fine-grained, dynamically recrystallized quartz bands. We attribute intracrystalline plasticity partitioning to variations in graphite inclusion concentration constraining quartz grain boundary mobility during dynamic recrystallization under non-coaxial strain regimes and moderate to elevated temperatures (400-650 °C). Lattice-preferred orientations of quartz [c] and axes are geometrically related to the external reference frame provided by foliations and lineations. We also identify the involvement of (0001), {r}, {m}, and {m}[c] quartz intracrystalline slip systems. Deformation modes operated simultaneously and under identical temperatures in interleaved parallel domains mm- to cm-thick in adjacent coarse- and fine-grained bands. Medium- to high-T plasticity is congruent with the syntectonic temperature gradients associated with the amphibolite-facies metamorphism of the country rocks. We also present the first specific study published so far on natural deformation graphite lattice-preferred orientation. Graphite inclusions (as well as those of mica) exhibit mineral shape fabrics that suggest operation of (0001) slip. However, EBSD measurements also record fabrics suggestive of {m} slip. In spite of a rather small volumetric proportion, graphite spatial organization at increased shear strains facilitated ductile deformation. If a graphite network is established in the rock, it can potentially increase rock electrical conductivity, thus accounting for mid and lower crust anomalous electric conductivity.

  20. Thermal dependence of luminescence lifetimes and radioluminescence in quartz

    Energy Technology Data Exchange (ETDEWEB)

    Pagonis, V., E-mail: vpagonis@mcdaniel.edu [McDaniel College, Physics Department, Westminster, MD 21157 (United States); Chithambo, M.L. [Department of Physics and Electronics, Rhodes University, PO BOX 94, Grahamstown 6140 (South Africa); Chen, R. [Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel); Chruścińska, A. [Institute of Physics, Nicholas Copernicus University, 87-100 Toruń (Poland); Fasoli, M. [Department of Materials Science, University of Milano-Bicocca, Via Cozzi 53, 20125 Milano (Italy); Li, S.H. [Department of Earth Sciences, The University of Hong Kong (Hong Kong); Martini, M. [Department of Materials Science, University of Milano-Bicocca, Via Cozzi 53, 20125 Milano (Italy); Ramseyer, K. [Institut für Geologie, Baltzerstrasse 1-3, 3012 Bern (Switzerland)

    2014-01-15

    During time-resolved optical stimulation experiments (TR-OSL), one uses short light pulses to separate the stimulation and emission of luminescence in time. Experimental TR-OSL results show that the luminescence lifetime in quartz of sedimentary origin is independent of annealing temperature below 500 °C, but decreases monotonically thereafter. These results have been interpreted previously empirically on the basis of the existence of two separate luminescence centers L{sub H} and L{sub L} in quartz, each with its own distinct luminescence lifetime. Additional experimental evidence also supports the presence of a non-luminescent hole reservoir R, which plays a critical role in the predose effect in this material. This paper extends a recently published analytical model for thermal quenching in quartz, to include the two luminescence centers L{sub H} and L{sub L}, as well as the hole reservoir R. The new extended model involves localized electronic transitions between energy states within the two luminescence centers, and is described by a system of differential equations based on the Mott–Seitz mechanism of thermal quenching. It is shown that by using simplifying physical assumptions, one can obtain analytical solutions for the intensity of the light during a TR-OSL experiment carried out with previously annealed samples. These analytical expressions are found to be in good agreement with the numerical solutions of the equations. The results from the model are shown to be in quantitative agreement with published experimental data for commercially available quartz samples. Specifically the model describes the variation of the luminescence lifetimes with (a) annealing temperatures between room temperature and 900 °C, and (b) with stimulation temperatures between 20 and 200 °C. This paper also reports new radioluminescence (RL) measurements carried out using the same commercially available quartz samples. Gaussian deconvolution of the RL emission spectra was

  1. A quartz Cherenkov detector for polarimetry at the ILC

    Energy Technology Data Exchange (ETDEWEB)

    Vauth, Annika

    2014-09-15

    At the proposed International Linear Collider (ILC), the use of polarised electron and positron beams is a key ingredient of the physics program. A measurement of the polarisation with a yet unprecedented precision of {sup δP}/{sub P}=0.25% is required. To achieve this, Compton polarimeter measurements in front of and behind the collision point are foreseen. In this thesis, a novel concept for a detector for ILC polarimetry is introduced to eliminate one of the dominating systematics limiting the previous best measurement of beam polarisation: a detector using quartz as Cherenkov medium could increase the tolerance against non-linear photodetector responses. The high refractive index of quartz results in a higher Cherenkov light yield compared to conventional Cherenkov gases. This could allow single-peak resolution in the Cherenkov photon spectra produced by the Compton electrons at the polarimeters. The detailed simulation studies presented in this work imply that such single-peak resolution is possible. Considerations for the choice of a suitable detector geometry are discussed. A four-channel prototype has been constructed and successfully operated in a first testbeam campaign at the DESY testbeam, confirming simulation predictions. Although further studies have to be considered to quantify all aspects of the detector response, the findings of the analysis of the data from the first testbeam are promising with regards to reaching the desired light yield. In the final part of this thesis, the application of a detector concept allowing single-peak resolution to the polarisation measurement at the ILC is examined. Two of the main sources of systematic uncertainties on the polarimeter measurements are detector non-linearities and misalignments. The performance of the suggested quartz detector concept in Monte Carlo studies promises a control of these systematics which meets the precision requirements for ILC polarimetry.

  2. The role of crustal quartz in controlling Cordilleran deformation.

    Science.gov (United States)

    Lowry, Anthony R; Pérez-Gussinyé, Marta

    2011-03-17

    Large-scale deformation of continents remains poorly understood more than 40 years after the plate tectonic revolution. Rock flow strength and mass density variations both contribute to stress, so both are certain to be important, but these depend (somewhat nebulously) on rock type, temperature and whether or not unbound water is present. Hence, it is unclear precisely how Earth material properties translate to continental deformation zones ranging from tens to thousands of kilometres in width, why deforming zones are sometimes interspersed with non-deforming blocks and why large earthquakes occasionally rupture in otherwise stable continental interiors. An important clue comes from observations that mountain belts and rift zones cyclically form at the same locations despite separation across vast gulfs of time (dubbed the Wilson tectonic cycle), accompanied by inversion of extensional basins and reactivation of faults and other structures formed in previous deformation events. Here we show that the abundance of crustal quartz, the weakest mineral in continental rocks, may strongly condition continental temperature and deformation. We use EarthScope seismic receiver functions, gravity and surface heat flow measurements to estimate thickness and seismic velocity ratio, v(P)/v(S), of continental crust in the western United States. The ratio v(P)/v(S) is relatively insensitive to temperature but very sensitive to quartz abundance. Our results demonstrate a surprising correlation of low crustal v(P)/v(S) with both higher lithospheric temperature and deformation of the Cordillera, the mountainous region of the western United States. The most plausible explanation for the relationship to temperature is a robust dynamical feedback, in which ductile strain first localizes in relatively weak, quartz-rich crust, and then initiates processes that promote advective warming, hydration and further weakening. The feedback mechanism proposed here would not only explain

  3. Extensive authigenic quartz overgrowths in the gas-bearing Haynesville-Bossier Shale, USA

    Science.gov (United States)

    Dowey, Patrick J.; Taylor, Kevin G.

    2017-07-01

    In sandstone reservoirs, despite grain rearrangement during compaction, significant pore volumes may be retained prior to the onset of late diagenetic quartz cementation. In mudstone reservoirs, grain rearrangement during compaction results in significant pore volume reduction prior to late diagenesis. Where quartz overgrowths have been previously reported in post-compaction mudstones they have been in volumetrically low concentrations and interpreted as anomalous occurrences. Quartz cementation alters rock brittleness resulting in changes to mechanical fracture properties. Quartz overgrowths reduce reservoir porosity and permeability. We present petrographic evidence of two phases of quartz cement in the Haynesville-Bossier Shale: (i) grain replacive and (ii) quartz overgrowths. Carbonate grain replacement is volumetrically low (primary granular framework surrounding engulfed detrital and early authigenic minerals would indicate that quartz overgrowths are also (iii) replacive. Pressure dissolution of detrital quartz silt grains and smectite-to-illite transformation are likely sources of silica for quartz cement. This study is the first to document large-scale, replacive, authigenic quartz overgrowth development within a producing mudstone.

  4. Quartz Crystal Microbalance Operation and In Situ Calibration

    Science.gov (United States)

    Albyn, K. C.

    2004-01-01

    Quartz crystal microbalances (QCMs) are commonly used to measure the rate of deposition of molecular species on a surface. The measurement is often used to select materials with a low outgassing rate for applications where the material has a line of sight to a contamination-sensitive surface. A quantitative, in situ calibration of the balance, or balances, using a pure material for which the enthalpy of sublimation is known, is described in this Technical Memorandum. Supporting calculations for surface dwell times of deposited materials and the effusion cell Clausing factor are presented along with examples of multiple QCM measurements of outgassing from a common source.

  5. Anisotropic ionic transport in quartz: the effect of twin boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Calleja, Mark [Mineral Physics Group, Department of Earth Sciences, University of Cambridge, Cambridge (United Kingdom)). E-mail: mcal00@esc.cam.ac.uk; Dove, Martin T.; Salje, Ekhard K.H. [Mineral Physics Group, Department of Earth Sciences, University of Cambridge, Cambridge (United Kingdom)

    2001-10-22

    Transport of Na{sup +} and Li{sup +} under the influence of an electric field in twinned quartz is simulated using molecular dynamics techniques. Comparison between bulk transport and transport along twin boundaries shows that the cations are trapped inside twin walls for weak fields along the crystallographic c-axis. Stronger fields lead to transport along twin walls with significantly lower mobility than in the bulk. With E along [110], transport in the wall is faster than in the bulk. We observe cation trapping preferentially in the twin walls when E is applied out of the plane of the wall. (author)

  6. The adsorption of methyl methacrylate and vinyl acetate polymers on α-quartz surface: A molecular dynamics study

    Science.gov (United States)

    Yan, Lijing; Yang, Yan; Jiang, Hui; Zhang, Bingjian; Zhang, Hui

    2016-01-01

    The molecular dynamics simulation was used to investigate the adsorption of polymethyl methacrylate (PMMA) and polyvinyl acetate (PVA), the commonly used surface coating materials, on α-quartz surface. The objective is to understand the interactions between quartz surface and polymers. The results clearly show adsorption of both polymers onto the quartz surface. Carbonyl group plays a significant role in the adsorption process. The adsorption energies of PMMA and PVA on α-quartz surface did not show significant difference, however, more hydrogen bonds were observed on the PVA/quartz system than PMMA/quartz. These observations might offer some insights on the polymer-quartz adhesion and its failure mechanism.

  7. Retrospective assessment of environmental dose rates using optically stimulated luminescence from Al2O3:C and quartz

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Banerjee, D.; Jungner, H.;

    1999-01-01

    As part of our continuing work on assessing the usefulness of natural and artificial dosemeters in retrospective accident dosimetry, the natural photon dose rates within bricks have been measured using the optically stimulated luminescence (OSL) from Al2O3:C single crystal dosemeters. These were...... placed in bricks in house walls for two weeks to integrate the environmental dose rates after which their OSL signals were measured. These results were compared with (1) OSL measurements of quartz samples extracted from the bricks and (2) dose rates determined from laboratory measurements of the natural...... crystals distributed in holes across a brick section and (2) quartz (extracted from the matrix of the brick) taken across the same section. These were compared with typical depth dose profiles found in bricks collected in the Chernobyl accident area and demonstrate retrospectively that the average energy...

  8. Performance of Ar+-milled Ti:Sapphire rib waveguides as single transverse-mode broadband fluorescence sources

    NARCIS (Netherlands)

    Grivas, C.; Shepherd, D.P.; May-Smith, T.C.; Eason, R.W.; Pollnau, Markus; Crunteanu, A.; Jelinek, M.

    2003-01-01

    Rib waveguides have been fabricated in pulsed-laser-deposited Ti:sapphire layers using photolithographic patterning and subsequent Ar+-beam milling. Fluorescence output powers up to 300 W have been observed from the ribs following excitation by a 3-W multiline argon laser. Mode intensity profiles sh

  9. ON-LINE SELF-CALIBRATING SINGLE CRYSTAL SAPPHIRE OPTICAL SENSOR INSTRUMENTATION FOR ACCURATE AND RELIABLE COAL GASIFIER TEMPERATURE MEASUREMENT

    Energy Technology Data Exchange (ETDEWEB)

    Kristie Cooper; Gary Pickrell; Anbo Wang

    2003-04-01

    This report summarizes technical progress over the first six months of the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. The objective of this program is to bring the BPDI sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. Research efforts were focused on analyzing and testing factors that impact performance degradation of the initially designed sensor prototype, including sensing element movement within the sensing probe and optical signal quality degradation. Based these results, a new version of the sensing system was designed by combining the sapphire disk sensing element and the single crystal zirconia right angle light reflector into one novel single crystal sapphire right angle prism. The new sensor prototype was tested up to 1650 C.

  10. Structural properties, crystal quality and growth modes of MOCVD-grown AlN with TMAl pretreatment of sapphire substrate

    Science.gov (United States)

    Sun, Haiding; Wu, Feng; tahtamouni, T. M. Al; Alfaraj, Nasir; Li, Kuang-Hui; Detchprohm, Theeradetch; Dupuis, Russell D.; Li, Xiaohang

    2017-10-01

    The growth of high quality AlN epitaxial films relies on precise control of the initial growth stages. In this work, we examined the influence of the trimethylaluminum (TMAl) pretreatment of sapphire substrates on the structural properties, crystal quality and growth modes of heteroepitaxial AlN films on (0 0 0 1) sapphire substrates. Without the pretreatment, the AlN films nucleated on the smooth surface but exhibited mixed crystallographic Al- (N-) polarity, resulting in rough AlN film surfaces. With increasing the pretreatment time from 1 to 5 s, the N-polarity started to be impeded. However, small islands were formed on sapphire surface due to the decompostion of TMAl. As a result, small voids became noticeable at the nucleation layer (NL) because the growth started as quasi three-dimensional (3D) but transformed to 2D mode as the film grew thicker and got coalesced, leading to smoother and Al-polar films. On the other hand, longer pretreatment time of 40 s formed large 3D islands on sapphire, and thus initiated a 3D-growth mode of the AlN film, generating Al-polar AlN nanocolumns with different facets, which resulted into rougher film surfaces. The epitaxial growth modes and their correlation with the AlN film crystal quality under different TMAl pretreatments are also discussed.

  11. The study on the nanomachining property and cutting model of single-crystal sapphire by atomic force microscopy.

    Science.gov (United States)

    Huang, Jen-Ching; Weng, Yung-Jin

    2014-01-01

    This study focused on the nanomachining property and cutting model of single-crystal sapphire during nanomachining. The coated diamond probe is used to as a tool, and the atomic force microscopy (AFM) is as an experimental platform for nanomachining. To understand the effect of normal force on single-crystal sapphire machining, this study tested nano-line machining and nano-rectangular pattern machining at different normal force. In nano-line machining test, the experimental results showed that the normal force increased, the groove depth from nano-line machining also increased. And the trend is logarithmic type. In nano-rectangular pattern machining test, it is found when the normal force increases, the groove depth also increased, but rather the accumulation of small chips. This paper combined the blew by air blower, the cleaning by ultrasonic cleaning machine and using contact mode probe to scan the surface topology after nanomaching, and proposed the "criterion of nanomachining cutting model," in order to determine the cutting model of single-crystal sapphire in the nanomachining is ductile regime cutting model or brittle regime cutting model. After analysis, the single-crystal sapphire substrate is processed in small normal force during nano-linear machining; its cutting modes are ductile regime cutting model. In the nano-rectangular pattern machining, due to the impact of machined zones overlap, the cutting mode is converted into a brittle regime cutting model.

  12. Intracavity doubling of CW Ti:sapphire laser to 392.5 nm using BiBO-crystal

    DEFF Research Database (Denmark)

    Mortensen, Jesper Liltorp; Thorhauge, Morten; Tidemand-Lichtenberg, Peter

    2005-01-01

    In this work we present results obtained for intra-cavity frequency-doubling of a 785 nm CW Ti:sapphire laser utilising BiBO as the non-linear crystal. Intracavity doubling offers several advantages compared to extra-cavity doubling, such as no need to couple to an external resonance cavity...

  13. Structural properties, crystal quality and growth modes of MOCVD-grown AlN with TMAl pretreatment of sapphire substrate

    KAUST Repository

    Sun, Haiding

    2017-08-08

    The growth of high quality AlN epitaxial films relies on precise control of the initial growth stages. In this work, we examined the influence of the trimethylaluminum (TMAl) pretreatment of sapphire substrates on the structural properties, crystal quality and growth modes of heteroepitaxial AlN films on (0001) sapphire substrates. Without the pretreatment, the AlN films nucleated on the smooth surface but exhibited mixed crystallographic Al- (N-) polarity, resulting in rough AlN film surfaces. With increasing the pretreatment time from 1 to 5 s, the N-polarity started to be impeded. However, small islands were formed on sapphire surface due to the decompostion of TMAl. As a result, small voids became noticeable at the nucleation layer (NL) because the growth started as quasi three-dimensional (3D) but transformed to 2D mode as the film grew thicker and got coalesced, leading to smoother and Al-polar films. On the other hand, longer pretreatment time of 40 s formed large 3D islands on sapphire, and thus initiated a 3D-growth mode of the AlN film, generating Al-polar AlN nanocolumns with different facets, which resulted into rougher film surfaces. The epitaxial growth modes and their correlation with the AlN film crystal quality under different TMAl pretreatments are also discussed.

  14. Performance of Ar+-milled Ti:Sapphire rib waveguides as single transverse mode broadband fluorescence sources

    NARCIS (Netherlands)

    Grivas, C.; Shepherd, D.P.; May-Smith, T.C.; Eason, R.W.; Pollnau, M.; Crunteanu, A.; Jelinek, M.

    2003-01-01

    Rib waveguides have been fabricated in pulsed-laser-deposited Ti:sapphire layers using photolithographic patterning and subsequent Ar+-beam milling. Fluorescence output powers up to 300 W have been observed from the ribs following excitation by a 3-W multiline argon laser. Mode intensity profiles sh

  15. Broadband single-transverse-mode fluorescence sources based on ribs fabricated in pulsed laser deposited Ti: sapphire waveguides

    NARCIS (Netherlands)

    Grivas, C.; May-Smith, T.C.; Shepherd, D.P.; Eason, R.W.; Pollnau, M.; Jelinek, M.

    2004-01-01

    Active rib waveguides with depths and widths varying from 3 to 5 μm and from 9 to 24 μm, respectively, have been structured by $Ar^{+}$-beam etching in pulsed laser deposited Ti:sapphire layers. Losses in the channel structures were essentially at the same levels as the unstructured planar waveguide

  16. Room-temperature continuous-wave operation of Ti:sapphire buried channel-waveguide lasers fabricated via proton implantation

    NARCIS (Netherlands)

    Grivas, C.; Shepherd, D.P.; Eason, R.W.; Laversenne, L.; Moretti, P.; Borca, C.N.; Pollnau, M.

    2006-01-01

    Fabrication and laser operation of proton-implanted Ti:sapphire buried channel waveguides is reported for the first time to our knowledge. Without any postimplantation annealing of the structures, continuous laser operation near 780 nm was demonstrated at room temperature at an absorbed pump power t

  17. Ti:sapphire rib waveguides as single-transverse-mode broadband fluorescence sources for optical coherence tomography applications

    NARCIS (Netherlands)

    Grivas, C.; Shepherd, D.P.; May-Smith, T.C.; Eason, R.W.; Pollnau, M.; Crunteanu, A.; Jelinek, M.

    2003-01-01

    Ar+-beam-milled rib waveguides in pulsed-laser-deposited Ti:sapphire layers show broadband single transverse mode fluorescence emission at output powers up to 300 μW and propagation losses comparable to those in unstructured planar waveguide counterparts.

  18. Impact of high-temperature annealing of AlN layer on sapphire and its thermodynamic principle

    Science.gov (United States)

    Fukuyama, Hiroyuki; Miyake, Hideto; Nishio, Gou; Suzuki, Shuhei; Hiramatsu, Kazumasa

    2016-05-01

    The N2-CO gas annealing technique was demonstrated to improve the crystalline quality of the AlN layer on sapphire. 300-nm-thick AlN layers were fabricated on sapphire substrates by a metal-organic vapor phase epitaxy method. The AlN layers were annealed in N2 and/or N2-CO gas atmosphere at 1923-1973 K for 0.5-4 h. Many pits and voids were observed on the AlN surface annealed in N2 atmosphere at 1973 K for 2 h. The rough surface was, however, much improved for the AlN annealed in N2-CO gas atmosphere. The thermodynamic principle of the N2-CO gas annealing technique is explained in this paper on the basis of the phase stability diagram of the Al2O3-AlN-C-N2-CO system. Voids and γ-aluminum oxynitride (γ-AlON) at the AlN/sapphire interface formed during the annealing, which is also explained on the basis of the phase stability diagram. The in-plane epitaxial relationships among AlN, γ-AlON, and sapphire are presented, and misfits among them are discussed.

  19. Influence of the preshock temperature on shock effects in quartz

    Science.gov (United States)

    Langenhorst, F.; Deutsch, A.

    1992-01-01

    Shock metamorphic features are the prime indicators for recognizing impact phenomena on Earth and other planetary bodies. Although the pressure dependence of shock features is well known, information about the influence of the preshock temperature is almost lacking. Especially in the case of large-scale impacts like Sudbury, it is expected that deep-seated crustal rocks were subjected to shock at elevated temperatures. Therefore, we continued to perform shock experiments at elevated temperatures on less than 0.5-mm thin disks of single crystal quartz cut parallel to the (1010) face. All recovered quartz samples were investigated by universal stage, spindle stage, and a newly developed density gradient technique. Errors of refractive index and density measurements are +/- 0.0005 and +/- 0.002 g/cu cm respectively. Our investigations indicate that shock metamorphic features are strongly dependent on the preshock temperature. This statement has far-reaching implications with respect to shock wave barometry that is based on data from recovery experiments at room temperature. These datasets might be applicable only to low-temperature target rocks. Moreover, this study demonstrates that shock recovery experiments are definitely required for understanding the complete pressure-temperature regime of shock metamorphism on planetary bodies.

  20. Mass production of CNTs using CVD multi-quartz tubes

    Energy Technology Data Exchange (ETDEWEB)

    Yousef, Samy; Mohamed, Alaa [Dept. of Production Engineering and Printing Technology, Akhbar Elyom Academy, Giza (Egypt)

    2016-11-15

    Carbon nanotubes (CNTs) have become the backbone of modern industries, including lightweight and heavy-duty industrial applications. Chemical vapor deposition (CVD) is considered as the most common method used to synthesize high yield CNTs. This work aims to develop the traditional CVD for the mass production of more economical CNTs, meeting the growing CNT demands among consumers by increasing the number of three particular reactors. All reactors housing is connected by small channels to provide the heat exchange possibility between the chambers, thereby decreasing synthesis time and reducing heat losses inside the ceramic body of the furnace. The novel design is simple and cheap with a lower reacting time and heat loss compared with the traditional CVD design. Methane, hydrogen, argon, and catalyzed iron nanoparticles were used as a carbon source and catalyst during the synthesis process. In addition, CNTs were produced using only a single quartz tube for comparison. The produced samples were examined using XRD, TEM, SEM, FTIR, and TGA. The results showed that the yield of CNTs increases by 287 % compared with those synthesized with a single quartz tube. Moreover, the total synthesis time of CNTs decreases by 37 % because of decreased heat leakage.

  1. A combined nanoplasmonic and electrodeless quartz crystal microbalance setup

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, Elin M.; Langhammer, Christoph; Zoric, Igor; Kasemo, Bengt [Department of Applied Physics, Chemical Physics Group, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Edvardsson, Malin E. M. [Department of Applied Physics, Biological Physics Group, Chalmers University of Technology, SE-41296 Gothenburg (Sweden)

    2009-12-15

    We have developed an instrument combining localized surface plasmon resonance (LSPR) sensing with electrodeless quartz crystal microbalance with dissipation monitoring (QCM-D). The two techniques can be run simultaneously, on the same sensor surface, and with the same time resolution and sensitivity as for the individual techniques. The electrodeless QCM eliminates the need to fabricate electrodes on the quartz crystal and gives a large flexibility in choosing the surface structure and coating for both QCM-D and LSPR. The performance is demonstrated for liquid phase measurements of lipid bilayer formation and biorecognition events, and for gas phase measurements of hydrogen uptake/release by palladium nanoparticles. Advantages of using the combined equipment for biomolecular adsorption studies include synchronized information about structural transformations and extraction of molecular (dry) mass and degree of hydration of the adlayer, which cannot be obtained with the individual techniques. In hydrogen storage studies the combined equipment, allows for synchronized measurements of uptake/release kinetics and quantification of stored hydrogen amounts in nanoparticles and films at practically interesting hydrogen pressures and temperatures.

  2. Infrared optical properties of $\\alpha$ quartz by molecular dynamics simulations

    CERN Document Server

    Gangemi, Fabrizio; Carati, Andrea; Maiocchi, Alberto; Galgani, Luigi

    2016-01-01

    This paper is concerned with theoretical estimates of the refractive--index curves for quartz, obtained by the Kubo formul\\ae\\ in the classical approximation, through MD simulations for the motions of the ions. Two objectives are considered. The first one is to understand the role of nonlinearities in situations where they are very large, as at the $\\alpha$--$\\beta$ structural phase transition. We show that on the one hand they don't play an essential role in connection with the form of the spectra in the infrared. On the other hand they play an essential role in introducing a chaoticity which involves a definite normal mode. This might explain why that mode is Raman active in the $\\alpha$ phase, but not in the $\\beta$ phase. The second objective concerns whether it is possible in a microscopic model to obtain normal mode frequencies, or peak frequencies in the optical spectra, that are in good agreement with the experimental data for quartz. Notwithstanding a lot of effort, we were unable to find results agr...

  3. Outbreak of silicosis in Spanish quartz conglomerate workers

    Science.gov (United States)

    Pérez-Alonso, Aránzazu; Córdoba-Doña, Juan Antonio; Millares-Lorenzo, José Luis; Figueroa-Murillo, Estrella; García-Vadillo, Cristina; Romero-Morillo, José

    2014-01-01

    Objectives: To describe the epidemiological and clinical characteristics of an outbreak of occupational silicosis and the associated working conditions. Methods: Cases were defined as men working in the stone cutting, shaping, and finishing industry in the province of Cádiz, diagnosed with silicosis between July 2009 and May 2012, and were identified and diagnosed by the department of pulmonology of the University Hospital of Puerto Real (Cádiz). A census of workplaces using quartz conglomerates was carried out to determine total numbers of potentially exposed workers. A patient telephone survey on occupational exposures and a review of medical records for all participants were conducted. Results: Silicosis was diagnosed in 46 men with a median age of 33 years and a median of 11 years working in the manufacturing of countertops. Of these cases, 91.3% were diagnosed with simple chronic silicosis, with an abnormal high-resolution computerized tomography (HRCT) scan. One patient died during the study period. Employer non-compliance in prevention and control measures was frequently reported, as were environmental and individual protection failures. Conclusions: The use of new construction materials such as quartz conglomerates has increased silicosis incidence due to intensive occupational exposures, in the context of high demand fuelled by the housing boom. This widespread exposure poses a risk if appropriate preventive measures are not undertaken. PMID:24804337

  4. Reactive ion etching of quartz and Pyrex for microelectronic applications

    Science.gov (United States)

    Zeze, D. A.; Forrest, R. D.; Carey, J. D.; Cox, D. C.; Robertson, I. D.; Weiss, B. L.; Silva, S. R. P.

    2002-10-01

    The reactive ion etching of quartz and Pyrex substrates was carried out using CF4/Ar and CF4/O2 gas mixtures in a combined radio frequency (rf)/microwave (μw) plasma. It was observed that the etch rate and the surface morphology of the etched regions depended on the gas mixture (CF4/Ar or CF4/O2), the relative concentration of CF4 in the gas mixture, the rf power (and the associated self-induced bias) and microwave power. An etch rate of 95 nm/min for quartz was achieved. For samples covered with a thin metal layer, ex situ high resolution scanning electron microscopy and atomic force microscopy imaging indicated that, during etching, surface roughness is produced on the surface beneath the thin metallic mask. Near vertical sidewalls with a taper angle greater than 80° and smooth etched surfaces at the nanometric scale were fabricated by carefully controlling the etching parameters and the masking technique. A simulation of the electrostatic field distribution was carried out to understand the etching process using these masks for the fabrication of high definition features.

  5. Evaluating the Type of Light Transmittance in Mono Crystalline, Poly Crystalline and Sapphire Brackets- An Invitro Spectrofluorometer Study.

    Science.gov (United States)

    Mohamed, Jauhar P; Kommi, Pradeep Babu; Kumar, M Senthil; Hanumanth; Venkatesan; Aniruddh; Arvinth; Kumar, Arani Nanda

    2016-08-01

    Most of the patients seek orthodontic treatment to improve the smile, which improves the facial profile by means of fixed appliances i.e., brackets and wires. The brackets are of different types like stainless steel and ceramic. Ceramic brackets were considered as aesthetic appliance which was divided into mono-crystalline, polycrystalline and sapphire brackets. The light transmittance might influence the degree of curing adhesive material in mono crystalline, polycrystalline and sapphire brackets. The aim of the present study was to evaluate the translucency and intensity of three different aesthetic brackets (mono crystalline, poly crystalline and sapphire ceramic brackets) and to determine their influence on shear bond strength of the brackets. The adhesive remnant index was also measured after debonding of the brackets from the tooth surface. Twenty six samples each of monocrystalline, polycrystalline and sapphire brackets (total 78 ceramic brackets) were used for the study. The bracket samples were subjected to optical fluorescence test using spectrofluorometer to measure the intensity of the brackets. Seventy eight extracted premolar teeth were procured and divided into 3 groups. The brackets were then bonded to the tooth using Transbond XT (3M Unitek) light cure composite material and cured with new light cure unit (Light Emitting Diode) of wood pecker company (400-450nm) for 30 seconds, and these samples were subjected to shear bond strength test with Instron Universal Testing Machine (UNITEK-94100) with a load range between 0 to 100 KN with a maximum cross head speed of 0.5mm/min. ARI (Adhesive Remnant Index) scores were evaluated according to Artun and Bergland scoring system using stereomicroscope at 20x magnification. The light absorption values obtained from spectrofluorometeric study were 3300000-3500000 cps for group 1 (monocrystalline ceramic brackets), 6000000-6500000 cps for Group 2 (polycrystalline ceramic brackets) and 2700000 -3000000 cps for

  6. Evaluating the Type of Light Transmittance in Mono Crystalline, Poly Crystalline and Sapphire Brackets- An Invitro Spectrofluorometer Study

    Science.gov (United States)

    Kommi, Pradeep Babu; Kumar, M Senthil; Hanumanth; Venkatesan; Aniruddh; Arvinth; Kumar, Arani Nanda

    2016-01-01

    Introduction Most of the patients seek orthodontic treatment to improve the smile, which improves the facial profile by means of fixed appliances i.e., brackets and wires. The brackets are of different types like stainless steel and ceramic. Ceramic brackets were considered as aesthetic appliance which was divided into mono-crystalline, polycrystalline and sapphire brackets. The light transmittance might influence the degree of curing adhesive material in mono crystalline, polycrystalline and sapphire brackets. Aim The aim of the present study was to evaluate the translucency and intensity of three different aesthetic brackets (mono crystalline, poly crystalline and sapphire ceramic brackets) and to determine their influence on shear bond strength of the brackets. The adhesive remnant index was also measured after debonding of the brackets from the tooth surface. Materials and Methods Twenty six samples each of monocrystalline, polycrystalline and sapphire brackets (total 78 ceramic brackets) were used for the study. The bracket samples were subjected to optical fluorescence test using spectrofluorometer to measure the intensity of the brackets. Seventy eight extracted premolar teeth were procured and divided into 3 groups. The brackets were then bonded to the tooth using Transbond XT (3M Unitek) light cure composite material and cured with new light cure unit (Light Emitting Diode) of wood pecker company (400-450nm) for 30 seconds, and these samples were subjected to shear bond strength test with Instron Universal Testing Machine (UNITEK-94100) with a load range between 0 to 100 KN with a maximum cross head speed of 0.5mm/min. ARI (Adhesive Remnant Index) scores were evaluated according to Artun and Bergland scoring system using stereomicroscope at 20x magnification. Results The light absorption values obtained from spectrofluorometeric study were 3300000–3500000 cps for group 1 (monocrystalline ceramic brackets), 6000000–6500000 cps for Group 2

  7. Dating recent floodplain sediments in the Hawkesbury-Nepean River system, eastern Australia using single-grain quartz OSL

    DEFF Research Database (Denmark)

    Sim, Anna K.; Thomsen, Kristina Jørkov; Murray, K.J.;

    2014-01-01

    (AMS) dates constrain these OSL ages. Quartz extracted from seven OSL samples from each of the cores was measured using both single-grain and multi-grain OSL techniques. Three of the single-grain natural dose distributions appear to be well bleached, but the others appear to be incompletely bleached...... incomplete bleaching is probably less important than postdepositional mixing and mixing during sampling. As a result, the burial age is probably best estimated using the weighted average of the individual single-grain dose estimates. The application of multi-grain OSL techniques to these samples results...

  8. Electrical and optical properties of VO2 thin films grown on various sapphire substrates by using RF sputtering deposition

    Science.gov (United States)

    Jung, Dae Ho; So, Hyeon Seob; Ko, Kun Hee; Park, Jun Woo; Lee, Hosun; Nguyen, Trang Thi Thu; Yoon, Seokhyun

    2016-12-01

    VO2 thin films were grown on a-, c-, m-, and r-plane sapphire and SiO2/Si substrates under identical conditions by using RF sputtering deposition from a VO2 target. The structural and the morphological properties of all VO2 films were investigated. The grain sizes of the VO2 films varied between 268 nm and 355 nm depending on the substrate's orientation. The electrical and the optical properties of all VO2 thin films were examined in detail. The metal-insulator transition temperature (TMI) varied with the substrate's orientation. The (200)/(bar 211 )-oriented VO2 films on the a-plane sapphire showed the lowest TMI of about 329.3 K (56.3 °C) while the (020)/(002)-VO2 films on the c-plane sapphire displayed the highest TMI of about 339.6 K (66.6 °C). The VO2 films showed reversible changes in the resistivity as large as 1.19 × 105 and a hysteresis of 2 K upon traversing the transition temperature. The variations observed in the TMI with respect to the substrate's orientation were due to changes in the lattice strain and the grain size distribution. Raman spectroscopy showed that metal (rutile) - insulator (monoclinic) transitions occurred via the M2 phase for VO2 films on the c-plane substrate rather than the direct M1 to rutile transition. The shifts in the phonon frequencies of the VO2 film grown on various sapphire substrates were explained in terms of the strain along the V-V atomic bond direction (cR). Our work shows a possible correlation between the transition parameters ( e.g., TMI, sharpness, and hysteresis width) and the width ( σ) of the grain size distribution. It also shows a possible correlation between the TMI and the resistivities at the insulating and the metallic phases for VO2 films grown on various sapphire substrates.

  9. 蓝宝石晶体的双面研磨加工%Dual-lapping process for sapphire crystal

    Institute of Scientific and Technical Information of China (English)

    文东辉; 洪滔; 张克华; 鲁聪达

    2009-01-01

    In order to achieve high efficiency and low damaged layers during a sapphire crystal lapping process,an experimental research on the rougness,lapping uniformity and sub-surface damaged layer were studied in this paper.The sapphire with (0001) orientation was lapped by 280 mesh boron carbide abrasive grits.The effects of lapping time on the material removal rates and surface roughness were investigated,and the processing remainders by the dual-lapping were determined in accordance with the surface states of the sapphire.Then micro-surface uniformity of the sapphire was also presented by using WYKO laser equipment.Finally,a nano-indentation test was carried out to measure the depth of damaged layer according to the hardness or modulus variances.Experimental results show that the sapphire crystal can offer the R,in 0.523 μm,R,<6.0 μm,the depth of heavy damaged layer of 460 nm,and the depth of sub-surface damaged layer no more than 1 μm,after it is lapped by the abrasive with 280 mesh boron carbide grits in 120 min.%为了实现对蓝宝石晶体的高效低损伤研磨加工,对蓝宝石晶体的双面研磨加工表面粗糙度、研磨均匀性和亚表面损伤层的深度进行实验研究.采用280min的双面研磨加工后可以获得Ra为0.523 μm,Rt<6.0 μm的表面;其深度损伤层约为460 nm,亚表面损伤层<1 μm.

  10. Investigation of a direction sensitive sapphire detector stack at the 5 GeV electron beam at DESY-II

    Science.gov (United States)

    Karacheban, O.; Afanaciev, K.; Hempel, M.; Henschel, H.; Lange, W.; Leonard, J. L.; Levy, I.; Lohmann, W.; Schuwalow, S.

    2015-08-01

    Extremely radiation hard sensors are needed in particle physics experiments to instrument the region near the beam pipe. Examples are beam halo and beam loss monitors at the Large Hadron Collider, FLASH or XFEL. Currently artificial diamond sensors are widely used. In this paper single crystal sapphire sensors are considered as a promising alternative. Industrially grown sapphire wafers are available in large sizes, are of low cost and, like diamond sensors, can be operated without cooling. Here we present results of an irradiation study done with sapphire sensors in a high intensity low energy electron beam. Then, a multichannel direction-sensitive sapphire detector stack is described. It comprises 8 sapphire plates of 1 cm2 size and 525 μ m thickness, metallized on both sides, and apposed to form a stack. Each second metal layer is supplied with a bias voltage, and the layers in between are connected to charge-sensitive preamplifiers. The performance of the detector was studied in a 5 GeV electron beam. The charge collection efficiency measured as a function of the bias voltage rises with the voltage, reaching about 10% at 095 V. The signal size obtained from electrons crossing the stack at this voltage is about 02200 e, where e is the unit charge. The signal size is measured as a function of the hit position, showing variations of up to 20% in the direction perpendicular to the beam and to the electric field. The measurement of the signal size as a function of the coordinate parallel to the electric field confirms the prediction that mainly electrons contribute to the signal. Also evidence for the presence of a polarisation field was observed.

  11. Preparation of Ce-doped colloidal SiO{sub 2} composite abrasives and their chemical mechanical polishing behavior on sapphire substrates

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Hong, E-mail: hong_lei2005@aliyun.com [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China); Research Center of Nano-science and Nano-technology, Shanghai University, Shanghai 200444 (China); Tong, Kaiyu; Wang, Zhanyong [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China)

    2016-04-01

    Chemical mechanical polishing (CMP) has become a widely accepted global planarization technology. Abrasive is one of key elements during CMP process. In order to enhance removal rate and improve surface quality of sapphire substrate, a series of novel Ce-doped colloidal SiO{sub 2} composite abrasives were prepared by chemical co-precipitation method. The CMP performances of the Ce-doped colloidal SiO{sub 2} composite abrasives on sapphire substrate were investigated by using UNIPOL-1502 polishing equipment. The analyses on the surface of polished sapphire substrate indicate that slurries containing the Ce-doped colloidal SiO{sub 2} composite abrasives exhibit lower surface roughness, higher material removal rate than that of pure colloidal SiO{sub 2} abrasive under the same testing conditions. Furthermore, the acting mechanism of the Ce-doped colloidal silica in sapphire CMP was investigated. X-ray photoelectron spectroscopy analysis shows that solid-state chemical reactions between Ce-doped silica abrasives and sapphire surface occur during CMP process, which can promote the chemical effect in CMP and lead to the improvement of material removing rate. - Highlights: • Novel Ce-doped colloidal SiO{sub 2} composite abrasives were prepared. • The chemical mechanical polishing (CMP) performances of the composite abrasives on sapphire substrate were investigated. • Novel composite abrasives show excellent polishing characteristics comparison with pure colloidal SiO{sub 2} abrasive. • We explore and report the acting mechanism of composite abrasives to sapphire CMP.

  12. Emplacement of cretaceous-tertiary boundary shocked quartz from chicxulub crater.

    Science.gov (United States)

    Alvarez, W; Claeys, P; Kieffer, S W

    1995-08-18

    Observations on shocked quartz in Cretaceous-Tertiary (K-T) boundary sediments compellingly tied to Chicxulub crater raise three problems. First, in North America shocked quartz occurs above the main K-T ejecta layer. Second, shocked quartz is more abundant west than east of Chicxulub. Third, shocked quartz reached distances requiring initial velocities up to 8 kilometers per second, corresponding to shock pressures that would produce melt, not the moderate-pressure shock lamellae observed. Shock devolatilization and the expansion of carbon dioxide and water from impacted wet carbonate, producing a warm, accelerating fireball after the initial hot fireball of silicate vapor, may explain all three problems.

  13. Changes in Quartz During Heating and the Possible Effects on Si Production

    Science.gov (United States)

    Ringdalen, Eli

    2015-02-01

    In Si and FeSi production, the main Si source is SiO2, in the form of quartz. Reactions with SiO2 generate SiO gas that further reacts with SiC to Si. During heating, quartz will transform to other SiO2 modifications with cristobalite as the stable high-temperature phase. Transformation to cristobalite is a slow process. Its rate has been investigated for several industrial quartz sources and has been shown to vary considerably among the different quartz types. Other differences in behavior during heating between these quartz sources, such as softening temperature and volume expansion, have also been studied. The quartz-cristobalite ratio will affect the rate of reactions involving SiO2. The industrial consequences and other implications of the observed difference between quartz types are discussed. Initial studies of industrial quartz were published by Ringdalen et al. In the current work, a new experimental method has been developed, and an investigation of several new quartz sources has confirmed the earlier observed large variation between different sources. The repeatability of the data has been studied and the effect of gas atmosphere investigated. The results from the earlier work are included as a basis for the discussion.

  14. Grain size distribution of quartz isolated from Chinese loess/paleosol

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Grain size distribution of bulk loess-paleosol and quartz chemically extracted from the loess/paleosol shows that mean size of the bulk samples is always finer than that of the quartz. The original aeolian depositions have been modified to various degrees by post-depositional weathering and pedogenic processes. The grain size distribution of the isolated quartz should be close to that of the primary aeolian sediment because the chemical pretreatment excludes secondary produced minerals. Therefore, the grain size of the quartz may be considered to more clearly reflect the variations of winter monsoon intensity.

  15. A Peltier cooled single pass amplifier for Titanium:Sapphire laser pulses

    Science.gov (United States)

    Ozawa, A.; Schneider, W.; Najafi, F.; Hänsch, T. W.; Udem, Th.; Hommelhoff, P.

    2010-05-01

    We report on a Peltier cooled single pass amplifier for high repetition rate Titanium:sapphire laser pulses. Pumped with 14 W and seeded with around 400 mW, the output reaches 1.1 W with good beam quality. This amplifier is very user-friendly, easy to maintain and set up and thus represents a device situated between more complicated liquid-nitrogen cooled amplifiers that can operate at higher pump power, and very simple near to room temperature amplifiers that can only be pumped with less power. In addition, we show the results of a finite element simulation on the temperature distribution in a liquid nitrogen cooled amplifier setup designed for highest output powers.

  16. Preparation and structural properties of YBCO films grown on GaN/c-sapphire hexagonal substrate

    Energy Technology Data Exchange (ETDEWEB)

    Chromik, S., E-mail: stefan.chromik@savba.sk [Institute of Electrical Engineering, SAS, Dubravska cesta 9, 84104 Bratislava (Slovakia); Gierlowski, P. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Spankova, M.; Dobrocka, E.; Vavra, I.; Strbik, V.; Lalinsky, T.; Sojkova, M. [Institute of Electrical Engineering, SAS, Dubravska cesta 9, 84104 Bratislava (Slovakia); Liday, J.; Vogrincic, P. [Department of Microelectronics, Slovak Technical University, Ilkovicova 3, 81219 Bratislava (Slovakia); Espinos, J.P. [Instituto de Ciencia de Materiales de Sevilla, Avda Americo Vespucio 49, 41092 Sevilla (Spain)

    2010-07-01

    Epitaxial YBCO thin films have been grown on hexagonal GaN/c-sapphire substrates using DC magnetron sputtering and pulsed laser deposition. An MgO buffer layer has been inserted between the substrate and the YBCO film as a diffusion barrier. X-ray diffraction analysis indicates a c-axis oriented growth of the YBCO films. {Phi}-scan shows surprisingly twelve maxima. Transmission electron microscopy analyses confirm an epitaxial growth of the YBCO blocks with a superposition of three a-b YBCO planes rotated by 120 deg. to each other. Auger electron spectroscopy and X-ray photoelectron spectroscopy reveal no surface contamination with Ga even if a maximum substrate temperature of 700 deg. C is applied.

  17. Nanosecond optical transmission studies of laser annealing in ion-implanted silicon-on-sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Lee, M.C.; Lo, H.W.; Aydinli, A.; Trott, G.J.; Compaan, A. (Kansas State Univ., Manhattan (USA). Dept. of Physics); Hale, E.B. (Missouri Univ., Rolla (USA). Dept. of Physics)

    1983-06-01

    Time-resolved optical transmission has been studied using 633 and 514 nm CW probes on ion-implantation-amorphized silicon-on-sapphire during annealing by a 10 nsec, approximately 1 J/cm/sup 2/ pulse at either 532 nm or 485 nm. As recrystallization sets in the transmitted signal at 514 nm rises by approximately 10/sup 3/ in approximately 60 nsec and provides a measure of regrowth velocity. Beyond 200 nsec the much slower transmission rise is used to provide an estimate of the Si cooling rate. The difference in transmission observed between initially crystalline and initially amorphous Si provide an estimate of the latent heat of recrystallization of the amorphous phase.

  18. Nonlinear Phase Distortion in a Ti:Sapphire Optical Amplifier for Optical Stochastic Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Andorf, Matthew [NICADD, DeKalb; Lebedev, Valeri [Fermilab; Piot, Philippe [NICADD, DeKalb; Ruan, Jinhao [Fermilab

    2016-06-01

    Optical Stochastic Cooling (OSC) has been considered for future high-luminosity colliders as it offers much faster cooling time in comparison to the micro-wave stochastic cooling. The OSC technique relies on collecting and amplifying a broadband optical signal from a pickup undulator and feeding the amplified signal back to the beam. It creates a corrective kick in a kicker undulator. Owing to its superb gain qualities and broadband amplification features, Titanium:Sapphire medium has been considered as a gain medium for the optical amplifier (OA) needed in the OSC*. A limiting factor for any OA used in OSC is the possibility of nonlinear phase distortions. In this paper we experimentally measure phase distortions by inserting a single-pass OA into one leg of a Mach-Zehnder interferometer. The measurement results are used to estimate the reduction of the corrective kick a particle would receive due to these phase distortions in the kicker undulator.

  19. The sapphire backscattering monochromator at the Dynamics beamline P01 of PETRA III

    Science.gov (United States)

    Alexeev, P.; Asadchikov, V.; Bessas, D.; Butashin, A.; Deryabin, A.; Dill, F.-U.; Ehnes, A.; Herlitschke, M.; Hermann, R. P.; Jafari, A.; Prokhorov, I.; Roshchin, B.; Röhlsberger, R.; Schlage, K.; Sergueev, I.; Siemens, A.; Wille, H.-C.

    2016-12-01

    We report on a high resolution sapphire backscattering monochromator installed at the Dynamics beamline P01 of PETRA III. The device enables nuclear resonance scattering experiments on Mössbauer isotopes with transition energies between 20 and 60 keV with sub-meV to meV resolution. In a first performance test with 119Sn nuclear resonance at a X-ray energy of 23.88 keV an energy resolution of 1.34 meV was achieved. The device extends the field of nuclear resonance scattering at the PETRA III synchrotron light source to many further isotopes like 151Eu, 149Sm, 161Dy, 125Te and 121Sb.

  20. Nanostructured sapphire vicinal surfaces as templates for the growth of self-organized oxide nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Thune, E., E-mail: elsa.thune@unilim.fr [Laboratoire Sciences des Procedes Ceramiques et de Traitements de Surface (SPCTS), UMR CNRS 6638, ENSCI, 47-73 Avenue Albert Thomas, F-87065 Limoges Cedex (France); Boulle, A. [Laboratoire Sciences des Procedes Ceramiques et de Traitements de Surface (SPCTS), UMR CNRS 6638, ENSCI, 47-73 Avenue Albert Thomas, F-87065 Limoges Cedex (France); Babonneau, D.; Pailloux, F. [Laboratoire de Physique des Materiaux (PHYMAT), UMR CNRS 6630, Universite de Poitiers, Boulevard Marie et Pierre Curie - Teleport 2, BP 30179, F-86962 Futuroscope - Chasseneuil Cedex (France); Hamd, W.; Guinebretiere, R. [Laboratoire Sciences des Procedes Ceramiques et de Traitements de Surface (SPCTS), UMR CNRS 6638, ENSCI, 47-73 Avenue Albert Thomas, F-87065 Limoges Cedex (France)

    2009-11-15

    Vicinal substrates of sapphire with miscut angle of 10 deg. from the (0 0 1) planes towards the [1 1 0] direction have been annealed in air in the range from 1000 to 1500 deg. C. The behaviour of these surfaces has been characterized as a function of the temperature and the thermal treatment time by Atomic Force Microscopy observations. A thermal treatment at 1250 deg. C allows to stabilize a surface made of periodically spaced nanosized step-bunches. Such stepped surfaces were used as template to grow self-patterned epitaxial oxide nanoparticles by thermal annealing of yttria-stabilized zirconia thin films produced by sol-gel dip-coating. Grazing Incidence Small Angle X-ray Scattering and High-Resolution Transmission Electron Microscopy were used to study the morphology of the nanoparticles and their epitaxial relationships with the substrate.