Journal articles: 'Quartz crystals Defects'

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Zhang, Xiao Jie. "Research on Synthetic Quartz Crystal Quality." Advanced Materials Research 716 (July 2013): 397–401. http://dx.doi.org/10.4028/www.scientific.net/amr.716.397.

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The quality of two synthetic quartz crystals, Z lump and Y bar, was researched by the infrared spectrophotometer technology and chemical spectral analysis in this study. The relationships between typical impurity OH and other impurities such as Fe, CO and Mg were discussed which impacted the quality of artificial rock crystal; the defects in artificial rock crystal and crystals, such as lattice dislocation and distortion with a close relation appear at the same time and impact the quality of synthetic quartz. The work in future should begin from the following two aspects in order to improve synthetic quartz crystal quality: the one is to further study the crystal structure characteristics and to explore the cutting type of crystal with convenient cultivation and processing process, high use ratio and high Q value. For example, the research is to make the Z area of Y bar crystals bigger and the other areas smaller or disappear. The other one is to improve the existing technological level and to reduce defects.

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Hyde, B., and A. Mclaren. "The Crystal Chemistry of Moganite and Amethyst." Australian Journal of Chemistry 49, no. 8 (1996): 861. http://dx.doi.org/10.1071/ch9960861.

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The crystal structure of moganite , SiO2, is described, analysed, and shown to be (mimetic) Brazil-twinned α-quartz: it consists of {1101} layers of the latter, one tetrahedron thick, coherently joined at composition planes, with left- and right-handed quartz layers alternating. The structure of the region immediately adjacent to a composition plane is identical to that found in macroscopically twinned quartz, e.g. in amethyst. Thus the 'defect' structure in the latter is the total structure of the former-a classic example of Wadsley's idea that, in crystals, 'defects' are stable structural entities.

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Bahadur, Harish. "Hydroxyl defects in Ge-doped cultured quartz crystals." Infrared Physics & Technology 36, no. 3 (April 1995): 685–90. http://dx.doi.org/10.1016/1350-4495(94)00095-3.

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4

van Horn, J. David, Fei Wu, Gerald Corsiglia, and Yan Ching Jean. "Asymmetric Positron Interactions with Chiral Quartz Crystals?" Defect and Diffusion Forum 373 (March 2017): 221–26. http://dx.doi.org/10.4028/www.scientific.net/ddf.373.221.

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We have studied the interaction of the positron with chiral left-or right-handed quartz crystals. In Doppler-broadening experiments, using a mono-energetic positron beam there is a differential depth profile for positrons implanted in LH or RH z-cut quartz as identified by a shape parameter (S). Further, in bulk positron annihilation lifetime spectroscopy (PALS) experiments, the lifetime (τ 2) attributed to free annihilation of the positron interacting with the chiral lattice exhibits a larger value for the LH quartz, and the associated intensity (I2) is also significantly different—RH quartz is consistently 10% greater than the LH crystal. The τ3 lifetime and its intensity, I3, attributed to positronium interacting with defects in the quartz, also appears to exhibit differences between the enantiomeric sets of crystals. These observations may demonstrate chiral recognition using a positron annihilation technique, pave the way for a broad range of positron experiments, and may help inform hypotheses of chirality recognition, selection, or induction by beta radiation.

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Boboyarova, Sh T., Sh A. Vakhidov, Zh D. Ibragimov, R. T. Turdiev, and O. B. Khushvakov. "The effect of structural defects in quartz crystals on radiation defect formation." Atomic Energy 87, no. 2 (August 1999): 607–10. http://dx.doi.org/10.1007/bf02673227.

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Bahadur, Harish. "Hydroxyl defects and electrodiffusion (sweeping) in natural quartz crystals." Journal of Applied Physics 73, no. 11 (June 1993): 7790–97. http://dx.doi.org/10.1063/1.353952.

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Nanev, N., and M. Wilkens. "Defects in quartz crystals initiated during their hydrothermal growth." Crystal Research and Technology 25, no. 5 (May 1990): 531–40. http://dx.doi.org/10.1002/crat.2170250515.

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8

Klemme, Stephan, Jasper Berndt, Constantinos Mavrogonatos, Stamatis Flemetakis, Ioannis Baziotis, Panagiotis Voudouris, and Stamatios Xydous. "On the Color and Genesis of Prase (Green Quartz) and Amethyst from the Island of Serifos, Cyclades, Greece." Minerals 8, no. 11 (October 26, 2018): 487. http://dx.doi.org/10.3390/min8110487.

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The color of quartz and other minerals can be either caused by defects in the crystal structure or by finely dispersed inclusions of other minerals within the crystals. In order to investigate the mineral chemistry and genesis of the famous prase (green quartz) and amethyst association from Serifos Island, Greece, we used electron microprobe analyses and oxygen isotope measurements of quartz. We show that the color of these green quartz crystals is caused by small and acicular amphibole inclusions. Our data also shows that there are two generations of amphibole inclusions within the green quartz crystals, which indicate that the fluid, from which both amphiboles and quartz have crystallized, must have had a change in its chemical composition during the crystallization process. The electron microprobe data also suggests that traces of iron may be responsible for the amethyst coloration. Both quartz varieties are characterized by isotopic compositions that suggest mixing of magmatic and meteoric/marine fluids. The contribution of meteoric fluid is more significant in the final stages and reflects amethyst precipitation under more oxidizing conditions.

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Barbee, Olivia, Craig Chesner, and Chad Deering. "Quartz crystals in Toba rhyolites show textures symptomatic of rapid crystallization." American Mineralogist 105, no. 2 (February 1, 2020): 194–226. http://dx.doi.org/10.2138/am-2020-6947.

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Abstract Textural and chemical heterogeneities in igneous quartz crystals preserve unique records of silicic magma evolution, yet their origins and applications are controversial. To improve our understanding of quartz textures and their formation, we examine those in crystal-laden rhyolites produced by the 74 ka Toba supereruption (>2800 km3) and its post-caldera extrusions. Quartz crystals in these deposits can reach unusually large sizes (10–20 mm) and are rife with imperfections and disequilibrium features, including embayments, melt inclusions, titanomagnetite and apatite inclusions, spongy morphologies, hollow faces, subgrain boundaries, multiple growth centers, and Ti-enriched arborescent zoning. Using a combination of qualitative and quantitative analyses (petrography, CL, EBSD, X-ray CT, LA-ICPMS), we determine that those textures commonly thought to signify crystal resorption, crystal deformation, synneusis, or fluctuating P–T conditions are here a consequence of rapid disequilibrium crystal growth. Most importantly, we discover that an overarching process of disequilibrium crystallization is manifested among these crystal features. We propose a model whereby early skeletal to dendritic quartz growth creates a causal sequence of textures derived from lattice mistakes that then proliferate during subsequent stages of slower polyhedral growth. In a reversed sequence, the same structural instabilities and defects form when slow polyhedral growth transitions late to fast skeletal-dendritic growth. Such morphological transitions result in texture interdependencies that become recorded in the textural-chemical stratigraphy of quartz, which may be unique to each crystal. Similar findings in petrologic experimental studies allow us to trace the textural network back to strong degrees of undercooling and supersaturation in the host melt, conditions likely introduced by dynamic magmatic processes acting on short geologic timescales. Because the textural network can manifest in single crystals, the overall morphology and chemistry of erupted quartz can reflect not only its last but its earliest growth behavior in the melt. Thus, our findings imply that thermodynamic disequilibrium crystallization can account for primary textural and chemical heterogeneities preserved in igneous quartz and may impact the application of quartz as a petrologic tool.

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Kristianpoller, N. "Defects induced in synthetic quartz crystals by vacuum-ultra-violet radiation." Physica Scripta 36, no. 1 (July 1, 1987): 179–83. http://dx.doi.org/10.1088/0031-8949/36/1/030.

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11

Huang, Xian-Rong, Thomas Gog, Jungho Kim, Elina Kasman, Ayman H. Said, Diego M. Casa, Michael Wieczorek, Marcelo G. Hönnicke, and Lahsen Assoufid. "Correct interpretation of diffraction properties of quartz crystals for X-ray optics applications." Journal of Applied Crystallography 51, no. 1 (February 1, 2018): 140–47. http://dx.doi.org/10.1107/s1600576717018155.

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Quartz has hundreds of strong Bragg reflections that may offer a great number of choices for making fixed-angle X-ray analyzers and polarizers at virtually any hard X-ray energies with selectable resolution. However, quartz crystals, unlike silicon and germanium, are chiral and may thus appear in two different forms of handedness that are mirror images. Furthermore, because of the threefold rotational symmetry along thecaxis, the {h1h2h3L} and {h2h1h3L} Bragg reflections may have quite different Darwin bandwidth, reflectivity and angular acceptance, although they have the same Bragg angle. The design of X-ray optics from quartz crystals therefore requires unambiguous determination of the orientation, handedness and polarity of the crystals. The Laue method and single-axis diffraction technique can provide such information, but the variety of conventions used in the literature to describe quartz structures has caused widespread confusion. The current studies give detailed guidelines for design and fabrication of quartz X-ray optics, with special emphasis on the correct interpretation of Laue patterns in terms of the crystallography and diffraction properties of quartz. Meanwhile, the quartz crystals examined were confirmed by X-ray topography to have acceptably low densities of dislocations and other defects, which is the foundation for developing high-resolution quartz-based X-ray optics.

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12

Lignie, Adrien, Dominique Granier, Pascale Armand, Julien Haines, and Philippe Papet. "Modulation of quartz-like GeO2structure by Si substitution: an X-ray diffraction study of Ge1−xSixO2(0 ≤x< 0.2) flux-grown single crystals." Journal of Applied Crystallography 45, no. 2 (March 15, 2012): 272–78. http://dx.doi.org/10.1107/s0021889812003081.

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The spontaneous nucleation by the high-temperature flux method of GeO2and SiO2-substituted GeO2(Ge1−xSixO2) compounds was improved to give single crystals free of hydroxy groups. The crystal structure and quality of these α-quartz-like piezoelectric materials were studied by single-crystal X-ray diffraction at room temperature. The refinements gave excellent final reliability factors, which are an indication of single crystals with a low level of defects. A good correlation was found between the silicon content in Ge1−xSixO2crystals determined through extrapolation from the inter-tetrahedral bridging angle and that found from energy-dispersive X-ray spectroscopy. The effect of germanium replacement by silicon on the distortion of the α-quartz-type GeO2structure was followed by the evolution of the intra-tetrahedral angle and other structural parameters. TheTO4(T= Si, Ge) distortion was found to be larger in α-GeO2than in α-SiO2and, as expected, the irregularity of theTO4tetrahedra decreased linearly as the substitution of Si for Ge increased.

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13

Bahadur, Harish. "Ion exchange and radiation response of H-related point defects in natural quartz crystals." Journal of Materials Research 9, no. 7 (July 1994): 1789–801. http://dx.doi.org/10.1557/jmr.1994.1789.

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Infrared absorption measurements have been used to study the radiation response of various hydroxyl point defects present in natural quartz crystals in their unswept, Na-swept, and H-swept conditions for “low-H” and “high-H” samples with similar aluminum concentration. The irradiation was done at 77 K, 300 K, and finally again at 77 K in sequence. At low-temperature irradiation the Al-OH− bands equalize in their intensity-like H-swept or prior 300 K-irradiated cultured quartz. Among other major bands the alkali-related centers show a reduction in their strength at all stages of irradiation. Purely H-related centers show no steady-state room temperature effects; only the low-temperature irradiation reduces their band strength. The results have been discussed in terms of proton and alkali ion motion to shallow and deep traps and compared with cultured quartz.

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14

Yoshimura, J., and S. Taki. "Acicular crystals of synthetic quartz; a general view of their morphologies and defects." Journal of Crystal Growth 125, no. 1-2 (November 1992): 237–50. http://dx.doi.org/10.1016/0022-0248(92)90338-j.

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15

Chorba, Onika, Mykhailo Filep, Artem Pogodin, Tetyana Malakhovska, and Marjan Sabov. "CRYSTALS GROWTH AND REFINEMENT OF THE Cu3SbSe3 CRYSTAL STRUCTURE." Ukrainian Chemistry Journal 88, no. 9 (October 28, 2022): 25–33. http://dx.doi.org/10.33609/2708-129x.88.09.2022.25-33.

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The technology of thermoelectric converters, based on the Peltier and Seebeck effects, provides a reversible process of convert in thermal and electrical energy. This opens up prospects for the creation of both thermoelectric coolers and thermoelectric generators. The most widely studied class of thermoelectric materials are complex chalcogenides. In recent years, copper-containing chalcogenides have been actively researched as new highly effective and ecologically friendly thermoelectric materials. The Cu–Sb–Se ternary system are characterized by the existence of three phases CuSbSe2, Cu3SbSe3 and Cu3SbSe4. Among these compounds, the Cu3SbSe3 phase is characterized by the lowest thermal conductivity. The synthesis of the Cu3SbSe3 polycrystalline alloy was carried out using high purity elementally components. The synthesis was carried out in vacuumed quartz ampoules by a one-temperature, two-stage process. Taking into account the incongruent melting of Cu3SbSe3, the single crystal growth was carried out by the method of vertical zone crystallization from a solution-melt in vacuumed conical quartz ampoules. As a result, the grown single crystal was dark gray color with metallic luster, without defects with length ~ 40 mm and diameter 12 mm. Obtained single crystalline sample of Cu3SbSe3 was investigated by DTA method. The heating curve contains one endothermic effect at 530°С, which corresponds to the process of peritectic decomposition of Cu3SbSe3. The effect corresponding to the melting of all components in the quartz container is not fixed. However, it is clearly visible on the cooling curve at 712 °С. The exothermic effect of crystallization of Cu3SbSe3 (503 °С) is clear and sharp and is observed with supercooling ΔТ = 27 °С. To confirm the single crystallinity of grown Cu3SbSe3 sample, an XRD analysis of the natural surface was carried out. The diffraction pattern shows two clear and narrow diffraction peaks corresponding to the (200) and (400) planes at angles of 22.27° and 45.42°, respectively. The crystal structure of the obtained Cu3SbSe3 single crystal was investigated by XRD analysis using the Rietveld full-profile refinement method. Established that Cu3SbSe3 crystallize in orthorhombic crystal system, SGPnma with lattice parameters: a = 7.9668 Å, b = 10.65870 Å, c = 6.8207 Å, Z = 4.

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16

Bahadur, Harish. "Radiation-induced modifications of point defects in quartz crystals and their application in radiation dosimetry." Radiation Measurements 36, no. 1-6 (June 2003): 493–97. http://dx.doi.org/10.1016/s1350-4487(03)00179-3.

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17

Ramseyer, K., J. Baumann, A. Matter, and J. Mullis. "Cathodoluminescence Colours of α-Quartz." Mineralogical Magazine 52, no. 368 (December 1988): 669–77. http://dx.doi.org/10.1180/minmag.1988.052.368.11.

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AbstractA new cathodoluminescence-microscope has been developed with a considerably improved detection limit. Time-dependent luminescence intensity changes observed during electron bombardment enabled the recognition of short-lived, long-lived, and brown luminescence colour types in α-quartz.Short-lived bottle-green or blue luminescence colours with zones of non-luminescing bands are very common in authigenic quartz overgrowths, fracture fillings or idiomorphic vein crystals. Dark brown, short-lived yellow or pink colours are often found in quartz replacing sulphate minerals. Quartz from tectonically active regions commonly exhibits a brown luminescence colour. A red luminescence colour is typical for quartz crystallized close to a volcanic dyke or sill.The causes of these different and previously poorly understood luminescence colours were investigated using heat treatment, electron bombardment and electrodiffusion. Both natural and induced brown luminescence colours reflect the presence of lattice defects (nonbonding Si-O) due to twinning, mechanical deformation, particle bombardment or extremely rapid growth. The bottle-green and blue linearly polarized luminescence colour, characterized by a plane of polarization parallel to the c-axis, both depend on the presence of interstitial cations. The yellow and red luminescence colours in α-quartz both exhibit a plane of polarization perpendicular to the c-axis and appear to be related to the presence of trace elements in an oxidizing solution and to ferric iron respectively.

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18

AlMasri, Nuha. "Investigations into the Metallic Impurity Problems Impacting the Growth of Synthetic Single Quartz Crystals and Defects." Tikrit Journal of Pure Science 23, no. 1 (April 1, 2018): 1–8. http://dx.doi.org/10.25130/tjps.23.2018.001.

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19

Bahadur, H. "Radiation response on Al-H, alkali-H and other H-related point defects in natural quartz crystals." IEEE Transactions on Nuclear Science 39, no. 6 (1992): 2170–77. http://dx.doi.org/10.1109/23.211418.

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20

Bahadur, H. "Irradiation effects on Ge-H, Al-H, and other H-related point defects in cultured quartz crystals." IEEE Transactions on Nuclear Science 43, no. 3 (June 1996): 2085–95. http://dx.doi.org/10.1109/23.502303.

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21

Bahadur, Harish. "A brief survey of aluminum and alkali-related hydroxyl defects in quartz crystals and their radiation effects." Radiation Physics and Chemistry 51, no. 4-6 (June 1998): 513–14. http://dx.doi.org/10.1016/s0969-806x(97)00187-4.

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22

Kaminsky, Werner, Trevor Snyder, and Peter Moeck. "3D printing of crystallographic models and open access databases." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C1278. http://dx.doi.org/10.1107/s205327331408721x.

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Although introduced 30 years ago, cost and performance improvements have only recently made 3D printing affordable. The industry wide input file format for 3D printers incorporates explicit mesh - `STL' data. Molecules and crystal structures, when including symmetry, crystal morphologies, or crystal defects are encoded in the parametrical `CIF' syntax. Free software for converting directly CIF data to STL files has just been developed, available online [1]. First examples of printed 3D models from STL-files created with these programs include molecules of sucrose, herapathite [2a], caffeine, humulone [2b], an alpha-quartz crystal and its Japanese {112} twin or a brilliant cut diamond. Far more CIF encoded models are available, even open access. The Crystallography Open Database (COD) features over 245,000 entries and has recently developed into the world's premier open-access source for structures of small to medium unit cell-sized inorganic and molecular crystals [3a], complementing the well-established open-access Worldwide Protein Data Bank [3b]. The Cambridge Crystallographic Data Centre in the United Kingdom provides crystal structure data of small (organic) molecules free for bona fide research [3c]. Structural data on inorganic crystals, metals and alloys can be obtained free of charge from the Inorganic Material Database (AtomWork) [3d]. Related to the COD, the crystallographic open-access databases [3e] ("COD offspring") provide CIF data for interdisciplinary college education. With this basic infrastructure in place, any interested college educator may print out her or his favorite crystallographic structure model in 3D and use it in hands on class room demonstrations [3f].

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Кузьмин, Н. Н., К. Н. Болдырев, Н. И. Леонюк, С. Ю. Стефанович, and М. Н. Попова. "Люминесцентные и нелинейно-оптические свойства боратов LnGa-=SUB=-3-=/SUB=-(BO-=SUB=-3-=/SUB=-)-=SUB=-4-=/SUB=- (Ln = Nd, Sm, Tb, Er, Dy, Ho)." Журнал технической физики 127, no. 7 (2019): 112. http://dx.doi.org/10.21883/os.2019.07.47937.101-19.

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AbstractLuminescence spectra of single crystals of rare-earth gallium borates LnGa_3(BO_3)_4 (Ln = Nd, Sm, Tb, Er, Dy, or Ho) at room (300 K) and cryogenic (10 K) temperatures are presented for the first time. Photoluminescence has been recorded in the wavelength range of 470–5000 nm (2000–21 300 cm^–1) with a high spectral resolution (down to 0.1 cm^–1) upon excitation by different diode lasers. The spectra obtained cannot be unambiguously interpreted within one luminescent center, which can be due to the presence of defects and/or inclusions of other crystalline phases. The optical nonlinearity of rare-earth–gallium borates has been estimated using the Kurtz–Perry powder technique. The typical intensities of the second-harmonic generation in gallium borate powders are 30–40 (with respect to quartz), and the optical nonlinearity is as good as the nonlinearity of the efficient rare-earth aluminum borate YAl_3(BO_3)_4.

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Li, Yong Peng, Hui Huang, and Xi Peng Xu. "Development Evaluation of Mechanical Properties of Brazed Diamond Wire." Solid State Phenomena 175 (June 2011): 294–99. http://dx.doi.org/10.4028/www.scientific.net/ssp.175.294.

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Fixed-abrasive wire saw, with its ability to cut hard brittle material, such as silicon ingots, crystals and quartz, has emerged as a leading technology for production in semiconductor and photovoltaic industry. There are some defects in conventional fixed-abrasive wire saw such as significant low holding abrasive ability, low machining efficiency, high running costs, etc. A new fixed-abrasive wire, namely brazed diamond wires have been developed to overcome these problems. In this paper, brazed diamond wire were carried out to braze two different size diamond grits onto two different thin steel wires by using a nickel-based powder as brazing alloy. The mechanical properties of brazed diamond wire were evaluated by tensile and breaking twist experiment. The experimental results showed that the heating in the brazing process has litter influence on the wire mechanical properties. The addition of brazed alloy and diamond grits sharply decreased the wire mechanical properties significantly, both in the tensile strength and breaking twist angle. Bigger diamond grit would make the accumulation of brazed alloy which leaded to the deterioration of diameter consistency of wires.

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Shankwitz, Jennifer, Daniel Speed, Dillon Sinanan, and Greg Szulczewski. "The Effects of Functional Groups and Missing Linkers on the Adsorption Capacity of Aromatic Hydrocarbons in UiO-66 Thin Films." Inorganics 9, no. 1 (December 26, 2020): 1. http://dx.doi.org/10.3390/inorganics9010001.

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The adsorption of benzene, toluene, ethylbenzene, and xylene isomers, also known as BTEX, from the gas phase into porous thin films of the metal–organic framework UiO-66-X, where X = H, NH2, and NO2, was measured to quantify adsorption capacity. The thin films were grown by a vapor-conversion method onto Au-coated quartz microbalance crystals. The MOF thin films were characterized by IR and Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The thin films were activated by heating under high vacuum and exposed to each gas to calculate the Henry’s constant. The results demonstrate that the functional groups in the organic linker and missing-linkers both play important roles in the adsorption capacity. Several trends can be observed in the data. First, all the compounds in the BTEX family have lower Henry’s constants in the UiO-66-H films compared to the UiO-66-NH2 and UiO-66-NO2 films, which can largely be attributed to the absence of a functional group on the linker. Second, at 25 °C, the Henry’s constants for all the BTEX compounds in UiO-66-NO2 films are larger than UiO-66-NH2 films. Third, the role of missing linkers is addressed by comparing the measured adsorption capacity to ideal pore filling. The results show that the UiO-66-H films are the most defect-free and the UiO-66-NO2 films have the most missing linker defects.

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Jollands, Michael C., Peter M. E. Tollan, Lukas P. Baumgartner, and Othmar Müntener. "Hydrogen diffusion mechanisms in quartz: insights from H–Li, ²H–H and ²H–H–Li exchange experiments." Mineralogical Magazine 86, no. 1 (January 7, 2022): 112–26. http://dx.doi.org/10.1180/mgm.2021.105.

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AbstractThe diffusivity and diffusion mechanisms of hydrogen together with with deuterium and lithium, parallel to the c axis of quartz, were investigated experimentally at 800°C, 0.1 GPa with the activity of H2O or 2H2O ≈ 1 [2H is used throughout this work to describe deuterium rather than D, to avoid confusion with the diffusion coefficient, D]. The pH was set using mixtures of H2O (or 2H2O) and HCl. Three types of experiment were conducted: (1) H-in/Li-out; (2) 2H-in/H-out; and (3) 2H-in/H + Li out, using three different natural quartz crystals as starting materials. Profiles of H, 2H and Li were measured using Fourier-transform infrared (FTIR) spectroscopy and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). H, 2H and Li are charge-compensated by Al3+ replacing Si4+, or by excess O2–. The total atomic concentration of monovalent cations appears to remain constant over the duration of the experiments. The resulting diffusion profiles are different for the three experimental designs and three starting materials, and some show complex shapes inconsistent with simple diffusion. A multi-site diffusion–reaction model is developed, with the theory based on previous models that have been derived mainly on the basis of conductivity measurements. In these models, the monovalent cations move away from their charge-balancing ion then diffuse rapidly to another site. The mobility of the monovalent cations is described by both a diffusion coefficient and an equilibrium constant that enables dissociation of the immobile charge-balanced defects. This model can describe complex step-shaped profiles formed in H-in/Li-out experiments, profiles with local maxima ('humped’ profiles) in 2H-in/H + Li out experiments, and error function-shaped profiles in 2H-in/H-out and previously published Li-in/H-out experiments. Our data provide support for models previously proposed for quartz. Studies of the lengths and forms of diffusion profiles from such experiments provide a useful complement to assertions from conductivity experiments.

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Загороднюк, Л., L. Zagorodnyuk, В. Уральский, Vladimir Ural'skiy, А. Уральский, Aleksey Ural'skiy, Д. Сумской, et al. "OBTAINING BINDING COMPOSITIONS FOR CONCRETE IN A CENTRIFUGAL GRINDING MILL." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 4, no. 10 (November 7, 2019): 123–34. http://dx.doi.org/10.34031/article_5db43db55dc701.66246266.

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Abstract. The results of studies on the grinding of waste wet magnetic separation of ferruginous quartz-ites of the Lebedinsky mining and processing plant in a centrifugal grinding unit are given, their grinding features are established. Binder compositions are obtained at different ratios of cement and wet magnetic separation waste in a centrifugal grinding mill at different grinding modes. The features of grinding process-es are studied, the technological and physicomechanical properties of the obtained binding compositions are determined. The data obtained indicate that the use of mineral filler up to 10% provides compaction of the structure due to the presence of fine mineral filler, which will reduce the consumption of Portland cement to 10%. During mechanical activation of the compositions of binding compositions, a sharp increase in the con-centration of surface defects occurs, due to the violation of contacts between crystals with the rupture of sili-con-oxygen valence bonds. The activity of the wet magnetic separation waste of ferruginous quartzites is ap-parently due to the presence of a large number of exchange centers on their surface, a significant part of which are Bronsted acids and bases. The processes of hydration and the formation of cement with the use of binders requires further detailed study.

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Damaskinskaya E. E., Hilarov V. L., Nosov Yu.G., Podurets K. M, Kaloyan A. A., Korost D. V., and Panteleev I. A. "Defect structure formation in quartz single crystal at the early stages of deformation." Physics of the Solid State 64, no. 4 (2022): 439. http://dx.doi.org/10.21883/pss.2022.04.53500.262.

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Accumulation of defects in the synthetic quartz single crystal has been investigated at the early stages of deformation. Process is studied with the help of three independent nondestructive techniques, namely: acoustic emission, X-ray computed tomography and synchrotron radiation topography. It is shown that results obtained by the three techniques are consistent with each other, allow detecting the area of defect formation and, what is more important, to match acoustic emission parameters with the ones of defects. This result is of practical importance, since it makes it possible to further identify areas of fracture growth and estimate their size in situ only by analyzing acoustic emission data in cases where the use of other control methods is impossible. Keywords: acoustic emission, X-ray computed tomography, synchrotron radiation topography (X-ray Diffraction Imaging), quartz single crystal, defects volume.

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Götze, Jens, Yuanming Pan, and Axel Müller. "Mineralogy and mineral chemistry of quartz: A review." Mineralogical Magazine 85, no. 5 (September 28, 2021): 639–64. http://dx.doi.org/10.1180/mgm.2021.72.

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AbstractQuartz (trigonal, low-temperature α-quartz) is the most important polymorph of the silica (SiO2) group and one of the purest minerals in the Earth crust. The mineralogy and mineral chemistry of quartz are determined mainly by its defect structure. Certain point defects, dislocations and micro-inclusions can be incorporated into quartz during crystallisation under various thermodynamic conditions and by secondary processes such as alteration, irradiation, diagenesis or metamorphism. The resulting real structure is a fingerprint of the specific physicochemical environment of quartz formation and also determines the quality and applications of SiO2 raw materials. Point defects in quartz can be related to imperfections associated with silicon or oxygen vacancies (intrinsic defects), to different types of displaced atoms, and/or to the incorporation of foreign ions in lattice sites and interstitial positions (extrinsic defects). Due to mismatch in charges and ionic radii only a limited number of ions can substitute for Si4+ in the crystal lattice or can be incorporated in interstitial positions. Therefore, most impurity elements in quartz are present at concentrations below 1 ppm. The structural incorporation in a regular Si4+ lattice site has been proven for Al3+, Ga3+, Fe3+, B3+, Ge4+, Ti4+, P5+ and H+, of which Al3+ is by far the most common and typically the most abundant. Unambiguous detection and characterisation of defect structures in quartz are a technical challenge and can only be successfully realised by a combination of advanced analytical methods such as electron paramagnetic resonance (EPR) spectroscopy, cathodoluminescence (CL) microscopy and spectroscopy as well as spatially resolved trace-element analysis such as laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and secondary-ion mass spectrometry (SIMS). The present paper presents a review of the state-of-the-art knowledge concerning the mineralogy and mineral-chemistry of quartz and illustrates important geological implications of the properties of quartz.

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Bahadur, Harish, and R. Parshad. "Effect of Irradiation on Crystal Defects in Quartz." IEEE Transactions on Nuclear Science 32, no. 2 (April 1985): 1169–79. http://dx.doi.org/10.1109/tns.1985.4333571.

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Fehlmann, M. "Crystal defects induced by device manufacture of quartz oscillators." Acta Crystallographica Section A Foundations of Crystallography 43, a1 (August 12, 1987): C206. http://dx.doi.org/10.1107/s0108767387079972.

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Дамаскинская, Е. Е., В. Л. Гиляров, Ю. Г. Носов, К. М. Подурец, А. А. Калоян, Д. В. Корост, and И. А. Пантелеев. "Формирование дефектной структуры монокристалла кварца на ранних этапах деформирования." Физика твердого тела 64, no. 4 (2022): 455. http://dx.doi.org/10.21883/ftt.2022.04.52185.262.

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Accumulation of defects in the synthetic quartz single crystal has been investigated at the early stages of deformation. Process is studied with the help of three independent nondestructive methods, namely: acoustic emission, X-ray computed tomography and synchrotron radiation topography. It is shown that results obtained by the three methods are consistent with each other, allow detecting the area of defect formation and, what is more important, to match acoustic emission parameters with the ones of defects. This result is of practical importance, since it makes it possible to further identify areas of fracture growth and estimate their size in situ only by analyzing acoustic emission data in cases where the use of other control methods is impossible.

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Jan, Pruška, A. N. Kravcov, I. E. Sas, E. B. Cherepetskaya, Jose Victorino Viegas, and N. G. Borisov. "Defect formation in synthetic quartz crystals under uniaxial compression." Mining informational and analytical bulletin, no. 4-1 (2021): 73–80. http://dx.doi.org/10.25018/0236_1493_2021_41_0_73.

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Singh, Lakhwant, Jaspal Singh, Surinder Singh, and H. S. Virk. "Recovery stages of heavy ion produced defects in quartz crystal." Nuclear Tracks and Radiation Measurements 22, no. 1-4 (January 1993): 229–32. http://dx.doi.org/10.1016/0969-8078(93)90055-9.

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Claridge, R. F. C., O. M. Kryliouk, J. A. Weil, and J. A. S. Williams. "Paramagnetic Ge–Li centres in alpha quartz revisited: The DLi([GeO4/Li]0D) centre." Canadian Journal of Physics 86, no. 11 (November 1, 2008): 1303–11. http://dx.doi.org/10.1139/p08-081.

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A previously unreported stable paramagnetic defect centre in single-crystal alpha-quartz has been studied by quantitative X-band electron paramagnetic resonance spectroscopy at 15, 100, and 296 K, and is shown to contain a Ge3+ ion, presumably located substitutional for Si4+, with a nearby interstitial Li+ ion. The centre, called DLi herein, grows in slowly (months) after room-temperature x-irradiation and storage. Hyperfine structure arising from 73Ge, 7Li, and 29Si has been observed. The spin-Hamiltonian parameter matrices g, A(7Li), A(73Ge), and P(73Ge) are reported, also for centre CLi. A thermal dynamic process, probably involving Li+ hopping, begins to be appreciable above 100 K. Discussion of DLi, its apparent growth from another paramagnetic centre (not yet fully characterized), and comparison with other similar defects is included.PACS Nos.: 42.70.Ce, 61.72.Hh, 61.72–y, 61.72S–, 61.72uf, 61.80–x, 76.30–v, 76.30.Mi

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Villa-Arango, Simón, David Betancur, Róbinson Torres, and Panayiotis Kyriacou. "Use of Transient Time Response as a Measure to Characterize Phononic Crystal Sensors." Sensors 18, no. 11 (October 25, 2018): 3618. http://dx.doi.org/10.3390/s18113618.

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Phononic crystals are periodic composite structures with specific resonant features that are gaining popularity in the field as liquid sensors. The introduction of a structural defect in an otherwise periodic regular arrangement can generate a resonant mode, also called defect mode, inside the characteristic band gaps of phononic crystals. The morphology, as well as the frequency in which these defect modes appear, can give useful information on the composition and properties of an analyte. Currently, only gain and frequency measurements are performed using phononic crystal sensors. Other measurements like the transient response have been implemented in resonant sensors such as quartz microbalances showing great results and proving to be a great complimentary measure to the gain and frequency measurements. In the present paper, a study of the feasibility of using the transient response as a measure to acquire additional information about the analyte is presented. Theoretical studies using the transmission line model were realized to show the impact of variations in the concentration of an analyte, in this case, lithium carbonate solutions, in the transient time of the system. Experimental realizations were also performed showing that the proposed measurement scheme presents significant changes in the resulting data, indicating the potential use of this measure in phononic crystal sensors. This proposed measure could be implemented as a stand-alone measure or as a compliment to current sensing modalities.

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Jafarov, M. B., and N. A. Verdiyeva. "Influence of γ-quanta on TlInSe2 crystal electrical properties." Chalcogenide Letters 19, no. 12 (December 21, 2022): 885–89. http://dx.doi.org/10.15251/cl.2022.1912.885.

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The influence of γ-quanta on the current flow in TlInSe2 single crystals and the process of filling and emptying localized levels in crystals has been experimentally studied. Investigations show that the current -voltage characteristics (CVC) of TlInSe2 single crystals obey Lampert theory and are determined by currents limited by the space charge. It is shown that the defects occurring from γ-quanta in TlInSe2 single crystals result from radiation processes

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Moritani, Kimikazu, Yoichi Teraoka, Ikuji Takagi, and Hirotake Moriyama. "Electron spin resonance measurement of irradiation defects produced in quartz crystal." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 232, no. 1-4 (May 2005): 317–21. http://dx.doi.org/10.1016/j.nimb.2005.03.065.

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Zhao, Shanrong, Jiyang Wang, Daliang Sun, Xiaobo Hu, and Hong Liu. "Twin structure in Yb:YAl3(BO3)4crystal." Journal of Applied Crystallography 34, no. 5 (September 25, 2001): 661–62. http://dx.doi.org/10.1107/s0021889801010834.

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Twin structure is a defect in the self-frequency-doubling laser crystal material Yb:YAl3(BO3)4(YbYAB). Based on atomic force microscopy (AFM) observations, a check-like twin structure in YbYAB crystals is found. This kind of twin structure has three twin composition planes: (10\bar{1}1), (0\bar{1}11) and (\bar{1}101). These three twin composition planes result in a series of twin boundaries in two directions, forming a check-like pattern on each face. From the orientation of the chemical etching pits on each side of the twin boundary, it is found that the twin element is `twin plane ⊥yaxis', alternatively indicated as `twin plane {11\bar{2}0}'. The two single crystals composing the twin are a right form and a left form. This kind of twin is similar to the Brazil twin found in quartz.

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Liu, Yu-Xin, Abdelkrim Talbi, Philippe Pernod, and Olivier Bou Matar. "Highly Confined Love Waves Modes by Defects States in a Phononic Crystal Based on Holey-SiO2/ST-Cut Quartz Structure." Proceedings 2, no. 13 (December 13, 2018): 729. http://dx.doi.org/10.3390/proceedings2130729.

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We investigate the properties of highly confined Love modes in a phononic crystal based on an array of holes made in SiO2 deposited on ST-cut Quartz substrate. An optimal choice of the geometrical parameters of the holes enables us to obtain wide stop-bands frequency for shear wave’s modes. The introduction of defect by removing lines of holes leads to nearly flat modes within the band gap and consequently paves the way to implement advanced design of electroacoustic filters and high-performance cavity resonators based on shear wave modes. The calculations are performed using finite element method based on the commercial software (COMSOL-Multiphysics). For transmission spectra, piezoelectric excitations are applied by considering the interdigital transducers, with results corroborating well the band structure predictions and the position of defects modes within the band gap.

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Kalashnikov, Evgenii, and Igor Tolstikhin. "Movement and Diffusion of the Helium Atom in Nanostructures (in Pores) with Water." Defect and Diffusion Forum 413 (December 17, 2021): 91–97. http://dx.doi.org/10.4028/www.scientific.net/ddf.413.91.

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The influence of water-filled nanoscale defects on the total movement of helium atoms through a quartz crystal is considered. The approximation of local chains is used, the interaction constant of which characterizes the interaction of the helium atom with the environment. The appearance of water molecules in defects (pores) leads to the renormalization of this interaction. The D'Alembert principle is used to evaluate this renormalization. The effect of such a renormalization of the interaction on the diffusion coefficient of helium through a crystal with defects filled with water is considered.

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Sebastian, M. T., A. Zarka, and B. Capelle. "A new X-ray topographic defect contrast on swept quartz crystals." Journal of Applied Crystallography 21, no. 4 (August 1, 1988): 326–29. http://dx.doi.org/10.1107/s0021889888002614.

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Sheinkman, Vladimir S., Yuliya Yu Erina, and Oleg A. Simonov. "NUMERICAL MODELING OF RADIATION EXPOSURE ON A QUARTZ CRYSTAL STRUCTURE DEFECTS AND SIGNAL ANALYSIS THERMOLUMINESCENT." Tyumen State University Herald. Physical and Mathematical Modeling. Oil, Gas, Energy 6, no. 4 (2020): 158–78. http://dx.doi.org/10.21684/2411-7978-2020-6-4-158-178.

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Developing thermoluminescent (TL) dating methods for quartz-containing deposits has required a series of numerical experiments within the framework of the band model to study the rate of electron accumulation in quartz crystal structure defects under radioactive radiation. The crystal model contained two different types of electron traps and one emission center. A system of differential equations was solved numerically, relating the rates of change in the electron concentration in defects of the crystal structure and the electron concentration in the conduction band and holes in the valence band. The results have shown that the intense radiation exposure alters the dynamic equilibrium concentration of electrons in the traps, which significantly modifies the TL signal. In accordance with this, the sensitivity marker material to the radioactive dose, required for absolute dating and received by its intense radiation exposure, cannot be determined correctly. In addition, the numerical experiments have confirmed the possibility of dating the samples by the position of the TL signal’s maximum on the time axis, as well as the possibility of obtaining the dating by the TL signal’s amplitude.

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Pan, Yuanming, Mark J. Nilges, and Rudolf I. Mashkovtsev. "Radiation-induced defects in quartz. II. Single-crystal W-band EPR study of a natural citrine quartz." Physics and Chemistry of Minerals 35, no. 7 (April 2, 2008): 387–97. http://dx.doi.org/10.1007/s00269-008-0233-7.

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Cai, Yanhuan, Changcheng Mi, and Xinming Huang. "The Artificial Mixed Fused Quartz Particles and Silicon Particles-Assisted High-Performance Multicrystalline Silicon." Crystals 9, no. 6 (June 1, 2019): 286. http://dx.doi.org/10.3390/cryst9060286.

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Mixed seeds of fused quartz particles and silicon particles were laid at the bottom of the crucible to assist the growth of multicrystalline silicon crystals. The full melting process was used, and then we found that the grown crystals had higher quality. The effect of mixed seeds on the growth of multicrystalline silicon was studied. The results showed that fine and uniform initial grains could be obtained by mixed seeds assisting the growth of crystals. Increasing the number of grain boundaries can better release thermal stress and inhibit the proliferation and diffusion of dislocations. The defect density of multicrystalline silicon decreased and the minority carrier lifetime increased, thus improving the conversion efficiency of multicrystalline silicon cells.

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Romanelli, Maurizio, Francesco Di Benedetto, Laura Bartali, Massimo Innocenti, Gabriele Fornaciai, Giordano Montegrossi, Luca A. Pardi, Alfonso Zoleo, and Fabio Capacci. "ESEEM of industrial quartz powders: insights into crystal chemistry of Al defects." Physics and Chemistry of Minerals 39, no. 6 (April 8, 2012): 479–90. http://dx.doi.org/10.1007/s00269-012-0502-3.

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Mustafakulov, A. A., O. N. Olimov, A. G. Parsokhonov, A. A. Akhmedov, and O. U. Nurullaev. "Study of the luminescence of SiO₂ crystals." Journal of Physics: Conference Series 2373, no. 8 (December 1, 2022): 082025. http://dx.doi.org/10.1088/1742-6596/2373/8/082025.

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Abstract The work represents the results of research into the issues of radiation materials science. The foundation of modern science and technology is the production of materials with predictable properties. In this regard, much attention is paid to issues related to the synthesis and growth of crystalline substances. The luminescent properties of quartz crystals grown on neutron-irradiated seeds were studied by the methods of gamma luminescence, thermo luminescence and thermal de-excitation. It has been established that in neutron-irradiated seeds and quartz crystals grown on them, there are defect centers belonging to the β-phase of quartz. The dependences of the concentration of these centers and β - phase on the neutron fluency correlate well with each other. A direct proof of the mechanism of the α - β-transition in quartz under neutron irradiation has been obtained.

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Argunova, T. S., L. M. Sorokin, B. Z. Pevzner, V. S. Balitskii, M. A. Gannibal, J. H. Je, Y. Hwu, and W. L. Tsai. "The influence of defects in the crystal structure on helium diffusion in quartz." Physics of the Solid State 45, no. 10 (October 2003): 1910–17. http://dx.doi.org/10.1134/1.1620094.

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Cordier, P., J. P. Morniroli, and D. Cherns. "Characterization of crystal defects in quartz by large-angle convergent-beam electron diffraction." Philosophical Magazine A 72, no. 5 (November 1995): 1421–30. http://dx.doi.org/10.1080/01418619508236266.

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Ricci, Giulia, Andrea Maurizio Monti, Renato Pagano, Marco Martini, Luisa Caneve, and Gilberto Artioli. "Unusual Luminescence of Quartz from La Sassa, Tuscany: Insights on the Crystal and Defect Nanostructure of Quartz." Minerals 11, no. 12 (November 30, 2021): 1345. http://dx.doi.org/10.3390/min11121345.

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Quartz from La Sassa (Tuscany, Italy) presents a unique luminescence related to intrinsic and extrinsic defects in the crystal lattice due to the growth mechanisms in hydrothermal conditions. The bright fluorescence under the UV lamp was apparent to collectors since the early 1970s, and it entered the literature as a reference case of yellow-luminescent quartz. Early reports present the history of the discovery, the geological context, and preliminary luminescence measurements of the quartz nodules, suggesting various activators as potentially responsible of the peculiar luminescence effects: uranyl groups (UO22+), rare earths (Tb3+, Eu3+, Dy3+, Sm3+, Ce3+) and polycyclic aromatic compounds (PAH). Here, we report a full investigation of the La Sassa material, by a multi-analytical approach encompassing cathodoluminescence optical microscopy (OM-CL), laser-induced fluorescence (LIF), wavelength resolved thermally stimulated luminescence (WR-TSL), trace elements analysis by mass spectrometry (ICP-MS) and Raman spectroscopy (RS). The results provide a significant step forward in the interpretation of the luminescence mechanisms: the main luminescent centres are identified as alkali-compensated (mainly Li+ and Na+, K+ and H+) aluminum [AlO4/M+]0 centres substituting for Si, where the recombination of a self-trapped exciton (STE) or an electron at a nonbridging oxygen hole centre (NBOHC) are active.

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Journal articles on the topic 'Quartz crystals Defects'

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