Silica Tube Research Articles

YRh2Ga – a new intergrowth variant of MgNi2 and CeCo3B2 related slabs

Abstract The gallide YRh2Ga was synthesized by melting of the elements in an arc-furnace followed by annealing in a sealed silica tube in an induction furnace. YRh2Ga crystallizes with a new structure type: P63/mmc, a=552.2(1), c=3119.5(6) pm, wR=0.0957, 497 F 2 values, and 34 variables. It is the n=1 member of the RE 2+n T 3+3n X 1+2n structure series with Laves phase (MgNi2 type in the present case) and CaCu5 (CeCo3B2 type in the present case) related slabs in the Parthé intergrowth concept.

Viscous behavior of synthetic silica glass tubes during collapsing

The viscous behavior of synthetic silica tubes is studied during collapsing. This technique can be applied directly during the modified chemical vapor deposition (MCVD) of light-guiding preform preparation. By performing several experiments with different tube dimensions, the material viscosity can be measured. In addition, information concerning the thermal behavior of the glass tubes during this process (the difference between the outer and inner temperature depending on the process conditions) can be derived, which is important for process control. This MCVD-inherent temperature difference is caused by radiation loss in wavelength regions in which quartz glass is semitransparent.

Layered tellurides: stacking faults induce low thermal conductivity in the new In2Ge2Te6 and thermoelectric properties of related compounds

A new ternary layered compound In2Ge2Te6, belonging to the hexatellurogermanate family has been synthesized from the reaction of appropriate amounts of the pure elements at high temperature in sealed silica tubes.

円形マイクロ流路内の非ニュートン流体の気液二相圧力損失

This study investigated pressure drop for gas and non-Newtonian liquid two-phase flows in a horizontal circular microchannel. The microchannel was a fused silica tube with 0.25 mm I.D. Polyacrylamide aqueous solutions with different mass concentration, which exhibit pseudo plastic behavior, were used as non-Newtonian liquid, while the nitrogen gas was used as the test gas. Pressure drop was measured with a calibrated differential pressure transducer. The pressure drop data have been compared with calculations by various correlations, usually used for prediction of the pressure drop in mini/micro channels as well as conventional sized channel. As the comparison results, the data have been correlated with separated flow model by using a newly developed equation of two-phase friction factor as well as homogenous flow model with an effective viscosity accounting for non-Newtonian effects. The Lockhart-Martinelli model also predicted well the present data if an appropriate C-value in two-phase friction multiplier was adopted.

An Experimental Study of the Formation of Talc through CaMg(CO3)2–SiO2–H2O Interaction at 100–200°C and Vapor-Saturation Pressures

The metamorphic interaction between carbonate and silica-rich fluid is common in geological environments. The formation of talc from dolomite and silica-rich fluid occurs at low temperatures in the metamorphism of the CaO–MgO–SiO2–CO2–H2O system and plays important roles in the formation of economically viable talc deposits, the modification of dolomite reservoirs, and other geological processes. However, disagreement remains over the conditions of talc formation at low temperatures. In this study, in situ Raman spectroscopy, quenched scanning electron microscopy, micro-X-ray diffraction, and thermodynamic calculations were used to explore the interplay between dolomite and silica-rich fluids at relatively low temperatures in fused silica tubes. Results showed that talc formed at ≤200°C and low CO2partial pressures (PCO2). The reaction rate increased with increasing temperature and decreased with increasingPCO2. The major contributions of this study are as follows:(1)we confirmed the formation mechanism of Mg-carbonate-hosted talc deposits and proved that talc can form at ≤200°C;(2)the presence of talc in carbonate reservoirs can indicate the activity of silica-rich hydrothermal fluids; and (3) the reactivity and solubility of silica require further consideration, when a fused silica tube is used as the reactor in highP–Texperiments.

A Hydrophobic Ionic Liquid Compartmentalized Sampling/Labelling and Its Separation Techniques in Polydimethylsiloxane Microchip Capillary Electrophoresis

This paper demonstrated a novel compartmentalized sampling/labelling method and its separation techniques using a hydrophobic ionic liquid (IL) – 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imidate (BmimNTf2) as immiscible phase, which is capable of minimizing signal losses during microchip capillary electrophoresis (MCE). The MCE device consists of a silica tube connecting to a straight polydimethylsiloxane (PDMS) separation channel. Poly(diallyldimethylammonium chloride) (PDDAC) was coated on the inner surface of channel for easing the introduction of IL plugs, and enhancing the IL wetting on the PDMS surface for realizing sample releasing. Electroosmotic flow (EOF)-based sample compartmentalization was carried out in a sequenced injection manner by order of leading IL plug/sample segment/terminal IL plug into sampling tube. The moving of the sample segment was easily controlled by applying electrical voltage across both end of the chip without sample volume change. This approach effectively prevented analytes diffusion before the injection into MCE channel. When the sample segment was manipulated to the PDDAC modified PDMS channel, the sample plug then was released from isolation under EOF while IL plugs adsorbed onto channel surface owing to strong adhesion. A mixture of flavin adenine nucleotide (FAD) and flavin mononucleotide (FMN) was successfully separated on a 2.5-cm-long separation channel, for which the theoretical number of plates was 15,000 and 17,000, respectively. The obtained peak intensity was increased by 6.3-folds compared to the corresponding value from conventional electrokinetic injection with same sampling time. Furthermore, based on the compartmented sample segment served as an interim reactor, an on-chip fluorescence labelling is demonstrated.

Na6Si3S8O: the first example of a sulfide silicate exhibiting unusual tri-polymerized [Si3S8O]6- units without S-O bonds.

Generally, sulfur is inclined to combine with oxygen to form sulfate ions in a solid-state reaction. Interestingly, an extraordinary sulfide silicate, Na6Si3S8O, was successfully obtained in a vacuum-sealed silica tube for the first time. Its crystal structure features novel 1D straight chains formed by the interconnection of tri-polymerized [Si3S8O]6- and [Na4S5O]11- units, demonstrating the first sulfide silicate exhibiting S-Na-O and S-Si-O connections without S-O bonds. Moreover, Na6Si3S8O is also verified as a promising birefringent material owing to its large birefringence (Δn = 0.215-0.094 from 0.3 to 4.0 μm).

Temperature-compensated fiber-optic Fabry–Perot interferometric gas refractive-index sensor based on hollow silica tube for high-temperature application

A temperature-compensated Fabry–Perot (FP) interferometric gas refractive-index (RI) sensor, fabricated by inserting a single-mode fiber (SMF) and a hollow silica tube (HST) with an inner diameter of 5μm, from opposite ends, into a silica casing, is described and experimentally demonstrated for high-temperature application. The thermal expansion of the silica casing and that of the SMF and HST offset each other when the SMF and HST are fixed far from their end facets. The lights are reflected and refracted multiple times between the end facets of the SMF and HST, and the RI changes in the open-cavity FP interferometric sensor can be detected by determining the wavelength shift of the interference spectrum. Experimental results show that the gas RI sensor has a linear sensitivity of approximately 1546nm/RIU from room temperature to 800°C. The gas RI sensor also has a temperature coefficient of approximately zero owing to its temperature-compensated structure.

The A-Type Ln4N2S3 Series: New Nitride Sulfides of the Light Lanthanoids (Ln = Ce–Nd)

The reaction of lanthanoid metal powders (Ln) with sulfur and cesium azide (CsN3) as a nitrogen source in the presence of lanthanoid tribromides (LnBr3) yields lanthanoid nitride sulfides with the composition Ln4N2S3 (Ln = Ce–Nd) when appropriate molar ratios of the starting material are used. Additional cesium bromide (CsBr) as a flux secures quantitative conversion (7 days) at 900 °C in evacuated silica tubes as well as the formation of black single crystals. All compounds crystallize isotypically with the orthorhombic crystal structure of La4N2S3 (Pnnm, Z = 2) and their structures were determined from single-crystal X-ray diffraction data (Ce4N2S3: a = 644.31(4), b = 1554.13(9), c = 404.20(3) pm; Pr4N2S3: a = 641.23(4), b = 1542.37(9), c = 400.18(3) pm; Nd4N2S3: a = 635.19(4), b = 1536.98(9), c = 397.85(3) pm). Compared to La4N2S3 the a-axes do not fulfill the expectation of the lanthanide contraction. The main feature of the crystal structure comprises N3−-centered (Ln3+)4 tetrahedra arranging as pairs [N2Ln6]12+ of edge-shared [NLn4]9+ units, which are further connected via four vertices to form double chains ∞ 1{([NLn4/2]2)6+}. Bundled along [001] like a hexagonal rod packing, they are held together by two crystallographically different S2− anions. Two compounds of a second modification (B-type La4N2S3 and Pr4N2S3) will also be presented and discussed for comparison.

ChemInform Abstract: Direct Gap Semiconductors Pb2BiS2I3, Sn2BiS2I3, and Sn2BiSI5.

AbstractPb2BiS2I3 (I), Sn2BiS2I3 (II), and Sn2BiSI5 (III) are prepared by solid state reaction of stoichiometric amounts of PbS and BiI3 for (I) (silica tube, 500 °C, 72 h; ≈90% yield) and from a 2:1:2:3.15 molar mixture of Sn, Bi, S, and I2 for mainly (II) and minor amounts of (III) (evacuated silica tubes, 500 °C, 24 h).

ChemInform Abstract: Metal Flux Growth, Structural Relations, and Physical Properties of EuCu2Ge2 and Eu3T2In9 (T: Cu and Ag).

AbstractSingle crystals of Eu3Ag2In9 (I) and EuCu2Ge2 (II) are grown from melts of the elements using In as a flux (Al2O3 crucible in evacuated silica tubes, 1.

ChemInform Abstract: Na9Sb(Ge2Q6)2 (Q: S, Se): Two New Antimony(III) Quaternary Chalcogenides with Ethane‐Like [Ge2Q6]6‐ Ligands.

AbstractAir‐stable crystals of Na9Sb(Ge2S6)2 (I) and Na9Sb(Ge2Se6)2 (II) are prepared by solid state reaction of stoichiometric amounts of the elements (evacuated silica tubes, 600 °C, 72 h; cooling to 300 °C at a rate of 3 °C/h).

Clustering of Yb in silica-based glasses synthesized by SPCVD

Light absorption and scattering are studied in silica-based slab lightguides with different contents of aluminum, ytterbium and phosphorous in the silica core. The slab lightguides used in the experiments were fabricated from the structures of doped silica deposited on the inner surface of a substrate silica tube via surface-plasma chemical vapor deposition (SPCVD). The synthesized glasses contained 0.004–0.4 at. % of Yb, as well as various contents of Al and P ranging from 0 to 1 at. %. Loss spectra of the slab lightguides are measured in the 300–1050 nm wavelength band, with the influence of the profusion of deposited glass on the loss spectra investigated by means of substrate tube external processing at a temperature of ∼1600 °C in the flame of a hydrogen-oxygen burner. We found that a combination of the temperature of the inner surface of the substrate tube during the deposition process and the subsequent profusion of the deposited structure essentially influence the distribution uniformity of ytterbium ions in the glass volume. If aluminum and phosphorous are present in the glass, such profusion can influence the formation of ytterbium clusters in opposite ways.

ChemInform Abstract: Concerted Rattling in CsAg5Te3 Leading to Ultralow Thermal Conductivity and High Thermoelectric Performance.

AbstractPure samples of the title p‐type material are obtained from stoichiometric mixtures of Ag, Te, and Cs2Te3 (silica tubes, 1073 K, 2 h).

ChemInform Abstract: Crystal Structure of BaMnB2O5 Containing Structurally Isolated Manganese Oxide Sheets.

AbstractThe title compound is prepared by melting a 2:1:1 molar mixture of MnO, BaO, and B2O3 in a CsCl/RbCl flux (evacuated silica tubes, 1.

ChemInform Abstract: One‐Dimensional Zinc Selenophosphates: A2ZnP2Se6 (A: K, Rb, Cs).

AbstractThe title compounds are prepared via molten salt flux syntheses from 2:1:2:10 molar mixtures of M2Se (M: K, Rb, Cs), Zn, P2Se5, and Se (evacuated silica tubes, 500 °C, 72 h; 95, 85, and 50% yields, respectively).

ChemInform Abstract: Pb2BO3Cl: A Tailor‐Made Polar Lead Borate Chloride with Very Strong Second Harmonic Generation.

AbstractSingle crystals of Pb2BO3Cl are grown from a 3:1:2 molar mixture of PbO, PbCl2 and H3BO3 (evacuated silica tubes, 720 °C, 24 h; cooling to 650 °C at a rate of 3 °C/h).

ChemInform Abstract: Er1.33Pt3Ga8: A Modulated Variant of the Er4Pt9Al24‐Structure Type.

AbstractSingle crystals of Er1.33Pt3Ga8 are grown in a molten Ga flux from a 1.33:1:15 molar mixture of Er, Pt, and Ga (Al2O3 crucible in evacuated silica tubes, 1150 °C, 7 h).

ChemInform Abstract: Syntheses of Six and Twelve Membered Borophosphate Ring Structure with Nonlinear Optical Activity.

AbstractLi3Cs2Ba2B3P6 O24 (I) is prepared by solid state reaction of a 1:2:1:2 molar mixture of Li2O, BaO, B2O3, and P2O5 (graphite crucible in evacuated silica tubes, complex heating schedule).

Highly Sensitive Temperature and Pressure Sensor Based on Fabry–Perot Interference

In this letter, we propose and experimentally demonstrate an optical fiber structure sensor using Fabry-Perot interference for temperature and pressure measurement. The sensor head consists of an incident single-mode fiber, a section of capillary pure silica tube, and refractive index matching fluid. The measurement of cavity length change with different pressure and temperature has been achieved by monitoring the wavelength shift of the interference pattern in the reflection spectra. For the change in a small scale, the measurement sensitivity of temperature is 6.95 nm/°C and the estimated sensitivity of pressure is 0.15 nm/Pa. The sensor has the advantages of high sensitivity, low cost, compact size, and flexibility.