Data Acquisition System for Quartz Crystal Microbalances

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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.

Miniature quartz crystal-resonator-based thermogravimetric detector.

Science.gov (United States)

Sai, N; Tagawa, Y; Sohgawa, M; Abe, T

2014-09-01

In this work, a new design for a microheater combined with a quartz crystal microbalance (QCM) array for thermogravimetric analysis is presented. Each QCM consists of two electrodes to excite thickness-shear-mode vibrations and one microheater to increase the temperature on the crystal backside. In addition, all the electrode pads are patterned on the crystal backside, making the design of the QCM compact and user-friendly. Finally, the proposed QCM array was employed to separate ethanol from methanol. This was successfully achieved via thermal desorption spectra calculated by differentiating the frequency changes.

Determination of antimony by using a quartz atom trap and electrochemical hydride generation atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Menemenlioglu, Ipek; Korkmaz, Deniz [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey); Ataman, O. Yavuz [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey)], E-mail: ataman@metu.edu.tr

2007-01-15

The analytical performance of a miniature quartz trap coupled with electrochemical hydride generator for antimony determination is described. A portion of the inlet arm of the conventional quartz tube atomizer was used as an integrated trap medium for on-line preconcentration of electrochemically generated hydrides. This configuration minimizes transfer lines and connections. A thin-layer of electrochemical flow through cell was constructed. Lead and platinum foils were employed as cathode and anode materials, respectively. Experimental operation conditions for hydride generation as well as the collection and revolatilization conditions for the generated hydrides in the inlet arm of the quartz tube atomizer were optimized. Interferences of copper, nickel, iron, cobalt, arsenic, selenium, lead and tin were examined both with and without the trap. 3{sigma} limit of detection was estimated as 0.053 {mu}g l{sup -1} for a sample size of 6.0 ml collected in 120 s. The trap has provided 18 fold sensitivity improvement as compared to electrochemical hydride generation alone. The accuracy of the proposed technique was evaluated with two standard reference materials; Trace Metals in Drinking Water, Cat CRM-TMDW and Metals on Soil/Sediment 4, IRM-008.

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

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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.

Correct interpretation of diffraction properties of quartz crystals for X-ray optics applications

Energy Technology Data Exchange (ETDEWEB)

Huang, Xian-Rong; Gog, Thomas; Kim, Jungho; Kasman, Elina; Said, Ayman H.; Casa, Diego M.; Wieczorek, Michael; Hönnicke, Marcelo G.; Assoufid, Lahsen

2018-02-01

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.

Historical review of quartz crystal growth

Science.gov (United States)

Iwasaki, Fumiko; Iwasaki, Hideo

2002-04-01

The history of quartz crystal growth is reviewed from the origin to the industrialization. The developing process of growth techniques is divided into the following three stages: (1) The fundamental work based on the mineralogical genetic view point, which was performed in Italy during the end of the 19th to the beginning of the 20th centuries. (2) The works to attempt the industrial application made in Germany and in England during World War II. (3) The industrialization of quartz growth after World War II. These were initiated in England, in USA and independently in Russia. The highest mass production process was developed in Japan. The historical flow is traced by the interview of several persons based on the original references.

The quartz crystal microbalance in soft matter research fundamentals and modeling

CERN Document Server

Johannsmann, Diethelm

2014-01-01

This book describes the physics of the second-generation quartz crystal microbalance (QCM), a fundamental method of analysis for soft matter at interfaces.From a device for measuring film thickness in vacuum, the quartz crystal microbalance (QCM) has in the past two decades evolved into a versatile instrument for analyzing soft matter at solid/liquid and solid/gas interfaces that found applications in diverse fields including the life sciences, material science, polymer research and electrochemistry. As a consequence of this success, the QCM is now being used by scientists with a wide variety

Effects of quartz on crystallization behavior of mold fluxes and microstructural characteristics of flux film.

Science.gov (United States)

Lei, Liu; Xiuli, Han; Mingduo, Li; Di, Zhang

2018-01-01

Mold fluxes are mainly prepared using cement clinker, quartz, wollastonite, borax, fluorite, soda ash and other mineral materials. Quartz, as one of the most common and essential materials, was chosen for this study to analyze itseffects on crystallization temperature, critical cooling rate, crystal incubation time, crystallization ratio and phases of flux film. We used the research methods of process mineralogy with the application of the single hot thermocouple technique, heat flux simulator, polarizing microscope, X-ray diffraction, etc. Results: By increasing the quartz content from 16 mass% to 24 mass%, the crystallization temperature, critical cooling rate and crystallization ratio of flux film decreased, and the crystal incubation time was extended. Meanwhile, the mineralogical structure of the flux film changed, with a large amount of wollastonite precipitation and a significant decrease in the cuspidine content until it reached zero. This showed a steady decline in the heat transfer control capacity of the flux film. The reason for the results above is that, by increasing the quartz content, the silicon-oxygen tetrahedron network structure promoted a rise in viscosity and restrained ion migration, inhibiting crystal nucleation and growth, leading to the weakening of the crystallization and a decline in the crystallization ratio.

A Review of Interface Electronic Systems for AT-cut Quartz Crystal Microbalance Applications in Liquids.

Science.gov (United States)

Arnau, Antonio

2008-01-21

From the first applications of AT-cut quartz crystals as sensors in solutionsmore than 20 years ago, the so-called quartz crystal microbalance (QCM) sensor isbecoming into a good alternative analytical method in a great deal of applications such asbiosensors, analysis of biomolecular interactions, study of bacterial adhesion at specificinterfaces, pathogen and microorganism detection, study of polymer film-biomolecule orcell-substrate interactions, immunosensors and an extensive use in fluids and polymercharacterization and electrochemical applications among others. The appropriateevaluation of this analytical method requires recognizing the different steps involved andto be conscious of their importance and limitations. The first step involved in a QCMsystem is the accurate and appropriate characterization of the sensor in relation to thespecific application. The use of the piezoelectric sensor in contact with solutions stronglyaffects its behavior and appropriate electronic interfaces must be used for an adequatesensor characterization. Systems based on different principles and techniques have beenimplemented during the last 25 years. The interface selection for the specific application isimportant and its limitations must be known to be conscious of its suitability, and foravoiding the possible error propagation in the interpretation of results. This article presentsa comprehensive overview of the different techniques used for AT-cut quartz crystalmicrobalance in in-solution applications, which are based on the following principles:network or impedance analyzers, decay methods, oscillators and lock-in techniques. Theelectronic interfaces based on oscillators and phase-locked techniques are treated in detail,with the description of different configurations, since these techniques are the most used inapplications for detection of analytes in solutions, and in those where a fast sensorresponse is necessary.

A Review of Interface Electronic Systems for AT-cut Quartz Crystal Microbalance Applications in Liquids

Directory of Open Access Journals (Sweden)

Antonio Arnau

2008-01-01

Full Text Available From the first applications of AT-cut quartz crystals as sensors in solutionsmore than 20 years ago, the so-called quartz crystal microbalance (QCM sensor isbecoming into a good alternative analytical method in a great deal of applications such asbiosensors, analysis of biomolecular interactions, study of bacterial adhesion at specificinterfaces, pathogen and microorganism detection, study of polymer film-biomolecule orcell-substrate interactions, immunosensors and an extensive use in fluids and polymercharacterization and electrochemical applications among others. The appropriateevaluation of this analytical method requires recognizing the different steps involved andto be conscious of their importance and limitations. The first step involved in a QCMsystem is the accurate and appropriate characterization of the sensor in relation to thespecific application. The use of the piezoelectric sensor in contact with solutions stronglyaffects its behavior and appropriate electronic interfaces must be used for an adequatesensor characterization. Systems based on different principles and techniques have beenimplemented during the last 25 years. The interface selection for the specific application isimportant and its limitations must be known to be conscious of its suitability, and foravoiding the possible error propagation in the interpretation of results. This article presentsa comprehensive overview of the different techniques used for AT-cut quartz crystalmicrobalance in in-solution applications, which are based on the following principles:network or impedance analyzers, decay methods, oscillators and lock-in techniques. Theelectronic interfaces based on oscillators and phase-locked techniques are treated in detail,with the description of different configurations, since these techniques are the most used inapplications for detection of analytes in solutions, and in those where a fast sensorresponse is necessary.

A study of positron properties in quartz crystals and synthetic silica glass

International Nuclear Information System (INIS)

Anwand, W.; Brauer, G.; Hesegawa, M.; Dersch, O.; Rauch, F.

2001-01-01

The monoenergetic positron beamline 'SPONSOR' at Rossendorf has been used to investigate the positron behaviour in a naturally grown Brasilian quartz, two synthetic quartz crystals of different origin, and synthetic silica glass. The measurements allow us to obtain the positron diffusion length of free positrons and Bloch para-positronium, if formed, in these materials. In addition, hydrothermal treatment of a synthetic quartz has been used to introduce hydrogen into the crystal up to a certain depth. The presence of hydrogen is found to influence the formation of para-positronium. The depth distribution of hydrogen has been measured independently by the nuclear reaction analysis, and will be discussed in comparison with the results deduced from the positron studies. (author)

Quartz Crystal Temperature Sensor for MAS NMR

Science.gov (United States)

Simon, Gerald

1997-10-01

Quartz crystal temperature sensors (QCTS) were tested for the first time as wireless thermometers in NMR MAS rotors utilizing the NMR RF technique itself for exiting and receiving electro-mechanical quartz resonances. This new tool in MAS NMR has a high sensitivity, linearity, and precision. When compared to the frequently used calibration of the variable temperature in the NMR system by a solid state NMR chemical shift thermometer (CST), such as lead nitrate, QCTS shows a number of advantages. It is an inert thermometer in close contact with solid samples operating parallel to the NMR experiment. QCTS can be manufactured for any frequency to be near a NMR frequency of interest (typically 1 to 2 MHz below or above). Due to the strong response of the crystal, signal detection is possible without changing the tuning of the MAS probe. The NMR signal is not influenced due to the relative sharp crystal resonance, restricted excitation by finite pulses, high probeQvalues, and commonly used audio filters. The quadratic dependence of the temperature increase on spinning speed is the same for the QCTS and for the CST lead nitrate and is discussed in terms of frictional heat in accordance with the literature about lead nitrate and with the results of a simple rotor speed jump experiment with differently radial located lead nitrate in the rotor.

A quartz crystal microbalance dew point sensor without frequency measurement

Science.gov (United States)

Wang, Guohua; Zhang, Weishuo; Wang, Shuo; Sun, Jinglin

2014-11-01

This work deals with the design of a dew point sensor based on Quartz Crystal Microbalance (QCM) without measuring the frequency. This idea is inspired by the fact that the Colpitts oscillation circuit will stop oscillating when the QCM works in the liquid media. The quartz crystal and the electrode are designed through the finite element simulation and the stop oscillating experiment is conducted to verify the sensibility. Moreover, the measurement result is calibrated to approach the true value. At last a series of dew points at the same temperature is measured with the designed sensor. Results show that the designed dew point sensor is able to detect the dew point with the proper accuracy.

Quartz crystal fabrication facility

Science.gov (United States)

Ney, R. J.

1980-05-01

The report describes the design and operation of a five chamber, interconnected vacuum system, which is capable of cleaning, plating, and sealing precision quartz crystal units in ceramic flatpack enclosures continuously in a high vacuum environment. The production rate design goal was 200 units per eight hour day. A unique nozzle beam gold deposition source was developed to operate for extended periods of time without reloading. The source puts out a narrow beam of gold typically in the order of 2 1/2 deg included cone angle. Maximum deposition rates are in the order of 400 a/min at 5.5 in. 'throw' distance used. Entrance and exit air lock chambers expedite the material throughput, so that the processing chambers are at high vacuum for extended periods of time. A stainless steel conveyor belt, in conjunction with three vacuum manipulators, transport the resonator components to the various work stations. Individual chambers are normally separated from each other by gate valves. The crystal resonators, mounted in flatpack frames but unplated, are loaded into transport trays in a lid-frame-lid sequency for insertion into the system and exit as completed crystal units. The system utilizes molybdenum coated ball bearings at essentially all friction surfaces. The gold sources and plating mask heads are equipped with elevators and gate valves, so that they can be removed from the system for maintenance without exposing the chambers to atmosphere.

Note: A quartz cell with Pt single crystal bead electrode for electrochemical scanning tunneling microscope measurements.

Science.gov (United States)

Xia, Zhigang; Wang, Jihao; Hou, Yubin; Lu, Qingyou

2014-09-01

In this paper, we provide and demonstrate a design of a unique cell with Pt single crystal bead electrode for electrochemical scanning tunneling microscope (ECSTM) measurements. The active metal Pt electrode can be protected from air contamination during the preparation process. The transparency of the cell allows the tip and bead to be aligned by direct observation. Based on this, a new and effective alignment method is introduced. The high-quality bead preparations through this new cell have been confirmed by the ECSTM images of Pt (111).

Quartz Crystal Microbalance Coated with Sol-gel-derived Thin Films as Gas Sensor for NO Detection

Directory of Open Access Journals (Sweden)

S. J. O’Shea

2003-10-01

Full Text Available This paper presents the possibilities and properties of Indium tin oxide (ITO-covered quartz crystal as a NOx toxic gas-sensor. The starting sol-gel solution was prepared by mixing indium chloride dissolved in acetylacetone and tin chloride dissolved in ethanol (0-20% by weight. The ITO thin films were deposited on the gold electrodes of quartz crystal by spin-coating technique and subsequently followed a standard photolithography to pattern the derived films to ensure all sensors with the same sensing areas. All heat treatment processes were controlled below 500°C in order to avoid the piezoelectric characteristics degradation of quartz crystal (Quartz will lose its piezoelectricity at ~573°C due to the phase change from α to β. The electrical and structural properties of ITO thin films were characterized with Hall analysis system, TG/DTA, XRD, XPS, SEM and etc. The gas sensor had featured with ITO thin films of ~100nm as the receptor to sense the toxic gas NO and quartz crystal with frequency of 10MHz as the transducer to transfer the surface reactions (mass loading, etc into the frequency shift. A homemade setup had been employed to measure the sensor response under the static mode. The experimental results had indicated that the ITO-coated QCM had a good sensitivity for NO gas, ~12Hz/100ppm within 5mins. These results prove that the ITO-covered quartz crystals are usable as a gas sensor and as an analytical device.

Scratching experiments on quartz crystals: Orientation effects in chipping

Science.gov (United States)

Tellier, C. R.; Benmessaouda, D.

1994-06-01

The deformation and microfracture properties of quartz crystals were studied by scratching experiments. The critical load at which microfractures are initiated was found to be orientation dependent, whereas the average width of ductile grooves and chips remained relatively insensitive to crystal orientation. In contrast, a marked anisotropy in the shape of chips was observed. This anisotropy has been interpreted in terms of microfractures propagating preferentially along slip planes. Simple geometrical conditions for the SEM (scanning electron microscopy) observation of active slip planes are proposed.

Recent Advances in Quartz Crystal Microbalance-Based Sensors

Directory of Open Access Journals (Sweden)

Sandeep Kumar Vashist

2011-01-01

Full Text Available Quartz crystal microbalance (QCM has gained exceptional importance in the fields of (biosensors, material science, environmental monitoring, and electrochemistry based on the phenomenal development in QCM-based sensing during the last two decades. This review provides an overview of recent advances made in QCM-based sensors, which have been widely employed in a plethora of applications for the detection of chemicals, biomolecules and microorganisms.

Continuous vacuum processing system for quartz crystal resonators

International Nuclear Information System (INIS)

Ney, R.J.; Hafner, E.

1979-01-01

An ultrahigh vacuum continuous cycle quartz crystal fabrication facility has been developed that assures an essentially contamination-free environment throughout the final manufacturing steps of the crystal unit. The system consists of five essentially tubular vacuum chambers that are interconnected through gate valves. The unplated crystal resonators, mounted in ceramic flatback frames and loaded on carrier trays, enter the vacuum system through an entrance air lock, are UV/ozone cleaned, baked at 300 0 C, plated to frequency, thermocompression sealed, and exit as completed crystal units through an exit air lock, while the bake, plate and seal chambers remain under continuous vacuum permanently. In-line conveyor belts are used, in conjunction with balanced vacuum manipulators, to move the resonator components to the various work stations. Unique high density, highly directional nozzle beam evaporation sources, capable of long term operation without reloading, are used for electroding the resonators simultaneously on both sides. The design goal for the system is a production rate of 200 units per 8 hour day; it is adaptable to automatic operation

Density-viscosity product of small-volume ionic liquid samples using quartz crystal impedance analysis.

Science.gov (United States)

McHale, Glen; Hardacre, Chris; Ge, Rile; Doy, Nicola; Allen, Ray W K; MacInnes, Jordan M; Bown, Mark R; Newton, Michael I

2008-08-01

Quartz crystal impedance analysis has been developed as a technique to assess whether room-temperature ionic liquids are Newtonian fluids and as a small-volume method for determining the values of their viscosity-density product, rho eta. Changes in the impedance spectrum of a 5-MHz fundamental frequency quartz crystal induced by a water-miscible room-temperature ionic liquid, 1-butyl-3-methylimiclazolium trifluoromethylsulfonate ([C4mim][OTf]), were measured. From coupled frequency shift and bandwidth changes as the concentration was varied from 0 to 100% ionic liquid, it was determined that this liquid provided a Newtonian response. A second water-immiscible ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [C4mim][NTf2], with concentration varied using methanol, was tested and also found to provide a Newtonian response. In both cases, the values of the square root of the viscosity-density product deduced from the small-volume quartz crystal technique were consistent with those measured using a viscometer and density meter. The third harmonic of the crystal was found to provide the closest agreement between the two measurement methods; the pure ionic liquids had the largest difference of approximately 10%. In addition, 18 pure ionic liquids were tested, and for 11 of these, good-quality frequency shift and bandwidth data were obtained; these 12 all had a Newtonian response. The frequency shift of the third harmonic was found to vary linearly with square root of viscosity-density product of the pure ionic liquids up to a value of square root(rho eta) approximately 18 kg m(-2) s(-1/2), but with a slope 10% smaller than that predicted by the Kanazawa and Gordon equation. It is envisaged that the quartz crystal technique could be used in a high-throughput microfluidic system for characterizing ionic liquids.

INTERFACE LAYER TO IMPROVE POLYSTYRENE ATTACHMENT ON A QUARTZ CRYSTAL RESONATOR

Directory of Open Access Journals (Sweden)

Doris Susana Llanes

Full Text Available Technologies for thin film deposition have been used to improve the functionalization of quartz crystal resonators (QCR; such technologies, for example, are spin coating and Langmuir-Blodgett (LB film preparation. These experiments are required because the film uniformity and homogeneity over the quartz crystal resonator are fundamental for its applications as chemical and biological sensors. Film deposition of polystyrene (PS particles, as well as polyvinyl chloride (PVC, was performed in solvents such as cyclohexanone, tetrahydrofuran (THF, dimethylformamide and chloroform at different concentrations using the spin coating procedure on wafer targets. The film quality was determined by optical microscopy, ellipsometry, and profilometry. Additionally, films on wafers or QCR with gold surface have been prepared by spreading the mentioned substances on an aqueous subphase and transferring it by dipping from the subphase surface onto the target. For LB film preparation arachidic acid and PS particles have been used. Prepared mono- or multilayered films of these substances on wafer or gold quartzes have been controlled additionally by IR-spectrometry. The resonant behavior of QCR before and after surface coating has been measured with a network analyzer. In combination with a graphical user interface the data could be easily recorded and visualized.

Thickness shear mode quartz crystal resonators with optimized elliptical electrodes

International Nuclear Information System (INIS)

Ma Ting-Feng; Feng Guan-Ping; Zhang Chao; Jiang Xiao-Ning

2011-01-01

Quartz crystal resonators (QCRs) with circular electrodes have been widely used for various liquid and gas sensing applications. In this work, quartz crystal resonators with elliptical electrodes were studied and tested for liquid property measurement. Mindlin's theory was used to optimize the dimension and geometry of the electrodes and a 5-MHz QCR with minimum series resistance and without any spurious modes was obtained. A series of AT-cut QCRs with elliptical electrodes of different sizes were fabricated and their sensing performances were compared to devices with circular electrodes. The experimental result shows that the device with elliptical electrodes can obtain lower resonance impedance and a higher Q factor, which results in a better loading capability. Even though the sensitivities of devices with elliptical and circular electrodes are found to be similar, the sensor with elliptical electrodes has much higher resolution due to a better frequency stability. The study indicates that the performance of QCRs with elliptical electrodes is superior to that of traditional QCRs with circular electrodes. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Temperature effect on phase states of quartz nano-crystals in silicon single crystal

International Nuclear Information System (INIS)

Kalanov, M.U.; Ibragimova, E.M.; Khamraeva, R.N.; Rustamova, V.M.; Ummatov, Kh.D.

2006-01-01

Full text: Oxygen penetrates into the silicon lattice up to the concentration of 2·10 18 cm -3 in the course of growing [1]. By the author's opinion at a low oxygen content the formation of solid solution is possible in the local defect places of the silicon single crystal lattice due to the difference in effective ion radius of oxygen and silicon (r O 0.176 and r Si = 0.065 nm). Upon reaching some critical content (∼ 10 17 cm -3 ), it becomes favorable energetically for oxygen ions to form precipitates (SiO x ) and finally a dielectric layer (stoichiometric inclusions of SiO 2 ). It was shown later that depending on the growth conditions, indeed the quartz crystal inclusions are formed in the silicon single crystals at an amount of 0.3 /0.5 wt. % [2]. However the authors did not study a phase state of the quartz inclusions. Therefore the aim of this work was to study a phase state of the quartz inclusions in silicon crystal at various temperatures. We examined the silicon single crystals grown by Czochralski technique, which were cut in (111) plane in the form of disk of 20 mm diameter and 1.5 thickness and had hole conductivity with the specific resistance ρ o ≅ 1/10 Ohm cm. The dislocation density was N D ≅ 10 1 /10 3 cm -2 , the concentrations of oxygen and boron were N 0 ≅ 2/ 4·10 17 cm -3 and N B ≅ 3*10 15 cm -3 . Structure was analyzed at the set-up DRON-UM1 with high temperature supply UVD-2000 ( CuK = 0.1542 nm) at the temperatures of 300, 1173 and 1573 K measured with platinum-platinum-rhodium thermocouple. The high temperature diffraction spectrum measured at 1573 K in the angle range (2Θ≅10/70 d egree ) there is only one main structure reflection (111) with a high intensity and d/n ≅ 0.3136 nm (2 Θ≅ 28.5 d egree ) from the matrix lattice of silicon single crystal. The weak line at 2 Θ≅ 25.5 d egree ( d/n≅0.3136 nm) is β component of the main reflection (111), and the weak structure peak at 2Θ≅59 d egree ( d/n≅ 0.1568 nm

Third harmonic frequency generation by type-I critically phase-matched LiB3O5 crystal by means of optically active quartz crystal.

Science.gov (United States)

Gapontsev, Valentin P; Tyrtyshnyy, Valentin A; Vershinin, Oleg I; Davydov, Boris L; Oulianov, Dmitri A

2013-02-11

We present a method of third harmonic generation at 355 nm by frequency mixing of fundamental and second harmonic radiation of an ytterbium nanosecond pulsed all-fiber laser in a type-I phase-matched LiB(3)O(5) (LBO) crystal where originally orthogonal polarization planes of the fundamental and second harmonic beams are aligned by an optically active quartz crystal. 8 W of ultraviolet light at 355 nm were achieved with 40% conversion efficiency from 1064 nm radiation. The conversion efficiency obtained in a type-I phase-matched LBO THG crystal was 1.6 times higher than the one achieved in a type-II LBO crystal at similar experimental conditions. In comparison to half-wave plates traditionally used for polarization alignment the optically active quartz crystal has much lower temperature dependence and requires simpler optical alignment.

Quartz-crystal microbalance study for characterizing atomic oxygen in plasma ash tools

International Nuclear Information System (INIS)

Srivastava, A.K.; Sakthivel, P.

2001-01-01

This article discusses the measurement of atomic oxygen (AO) concentrations in an oxygen discharge using a quartz-crystal microbalance (QCM). This is a device that has been previously used for monitoring thin-film deposition, among several other applications. The sensor consists of a silver-coated quartz crystal that oscillates at its specific resonant frequency (typically, at about 6 MHz), which is dependent on the mass of the crystal. When exposed to AO, the silver oxidizes rapidly, resulting in a change in its mass, and a consequent change in this frequency. The frequency change is measured with a counter, and when plotted versus time, it may be fit to a standard diffusion-limited oxide-growth model. This model is then used to determine the specific AO flux to the crystal, and by inference, to the wafer. Initial results of QCM measurements in the FusionGemini Plasma Asher (GPL TM -standard downstream microwave asher) and FusionGemini Enhanced Strip (GES TM -fluorine compatible enhanced strip asher) are presented in this article. The results indicate AO densities of the order of 10 12 cm -3 on the wafer. There is a marked increase in AO concentration with addition of nitrogen into the plasma, and a decrease in AO concentration with increasing pressure at constant flow. Effects of increasing the total plasma volume in the enhanced strip tool on AO production are discussed

Use of quartz crystal nanobalance to study the binding and stabilization of albumin and doxycycline on a thin layer of hydroxyapatite

Science.gov (United States)

Victor, Sunita Prem; Sharma, Chandra P.; Sreenivasan, K.

2011-12-01

This study reports the use of quartz crystal nanobalance (QCN) to study the adsorption of two model molecules namely albumin and doxycycline by hydroxyapatite (HA). The work focuses on the deposition of a stable coating of HA on the quartz crystal, modification of the coating using doxycycline and its subsequent effects on albumin adsorption. The uniformity and thickness of the HA coating has been studied using atomic force microscopy (AFM). The functional groups to ascertain the presence of the selected moieties have been characterized by Raman spectroscopy. The results indicate that the mass of albumin deposited on the surface of the HA coated quartz crystal functionalized with doxycycline shows a substantial increase when compared to the standard HA coated quartz crystal. The adsorbed albumin has also been found to be retained for an enhanced period of time. This surface immobilization of doxycycline and subsequent albumin adsorption seem to be a promising approach to confer biomaterials with antithrombogenic and antibacterial surfaces.

Use of quartz crystal nanobalance to study the binding and stabilization of albumin and doxycycline on a thin layer of hydroxyapatite

Energy Technology Data Exchange (ETDEWEB)

Victor, Sunita Prem [Biosurface Technology Division, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum 695012, Kerala (India); Sharma, Chandra P., E-mail: sharmacp@sctmist.ac.in [Biosurface Technology Division, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum 695012, Kerala (India); Sreenivasan, K. [Biosurface Technology Division, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum 695012, Kerala (India); Laboratory for Polymer Analysis, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum 695012, Kerala (India)

2011-12-15

This study reports the use of quartz crystal nanobalance (QCN) to study the adsorption of two model molecules namely albumin and doxycycline by hydroxyapatite (HA). The work focuses on the deposition of a stable coating of HA on the quartz crystal, modification of the coating using doxycycline and its subsequent effects on albumin adsorption. The uniformity and thickness of the HA coating has been studied using atomic force microscopy (AFM). The functional groups to ascertain the presence of the selected moieties have been characterized by Raman spectroscopy. The results indicate that the mass of albumin deposited on the surface of the HA coated quartz crystal functionalized with doxycycline shows a substantial increase when compared to the standard HA coated quartz crystal. The adsorbed albumin has also been found to be retained for an enhanced period of time. This surface immobilization of doxycycline and subsequent albumin adsorption seem to be a promising approach to confer biomaterials with antithrombogenic and antibacterial surfaces.

Use of quartz crystal nanobalance to study the binding and stabilization of albumin and doxycycline on a thin layer of hydroxyapatite

International Nuclear Information System (INIS)

Victor, Sunita Prem; Sharma, Chandra P.; Sreenivasan, K.

2011-01-01

This study reports the use of quartz crystal nanobalance (QCN) to study the adsorption of two model molecules namely albumin and doxycycline by hydroxyapatite (HA). The work focuses on the deposition of a stable coating of HA on the quartz crystal, modification of the coating using doxycycline and its subsequent effects on albumin adsorption. The uniformity and thickness of the HA coating has been studied using atomic force microscopy (AFM). The functional groups to ascertain the presence of the selected moieties have been characterized by Raman spectroscopy. The results indicate that the mass of albumin deposited on the surface of the HA coated quartz crystal functionalized with doxycycline shows a substantial increase when compared to the standard HA coated quartz crystal. The adsorbed albumin has also been found to be retained for an enhanced period of time. This surface immobilization of doxycycline and subsequent albumin adsorption seem to be a promising approach to confer biomaterials with antithrombogenic and antibacterial surfaces.

Application of an Electrochemical Quartz Crystal Microbalance to the study of electrocatalytic films

Energy Technology Data Exchange (ETDEWEB)

Gordon, Jr., James S. [Iowa State Univ., Ames, IA (United States)

1993-09-01

The EQCM was used to study the deposition and composition of electrodeposited pure PbO₂ and Bi-doped PbO₂ active toward anodic oxygen-transfer reactions. Within the doped films, Bi is incorporated as Bi⁺⁵ in the form of BiO₂A, where A is ClO₄^- or NO₃^-. For deposition of these 2 materials, changes in hydration between the Au oxide and the depositing film resulted in higher mass-to-charge ratios. XRD and XPS were used to study the films; the rutile structure of PbO₂ is retained even with the Bi doping. The EQCM was also used to study the formation and dissolution of Au oxide and preoxide structures formed on the Au substrate electrodes in acidic media. The preoxide structures were AuOH and increased the surface mass. For the formation of stable Au films on quartz wafers, Ti interlayers between Au and quartz was found to be very effective.

Accurate dew-point measurement over a wide temperature range using a quartz crystal microbalance dew-point sensor

Science.gov (United States)

Kwon, Su-Yong; Kim, Jong-Chul; Choi, Buyng-Il

2008-11-01

Quartz crystal microbalance (QCM) dew-point sensors are based on frequency measurement, and so have fast response time, high sensitivity and high accuracy. Recently, we have reported that they have the very convenient attribute of being able to distinguish between supercooled dew and frost from a single scan through the resonant frequency of the quartz resonator as a function of the temperature. In addition to these advantages, by using three different types of heat sinks, we have developed a QCM dew/frost-point sensor with a very wide working temperature range (-90 °C to 15 °C). The temperature of the quartz surface can be obtained effectively by measuring the temperature of the quartz crystal holder and using temperature compensation curves (which showed a high level of repeatability and reproducibility). The measured dew/frost points showed very good agreement with reference values and were within ±0.1 °C over the whole temperature range.

Accurate dew-point measurement over a wide temperature range using a quartz crystal microbalance dew-point sensor

International Nuclear Information System (INIS)

Kwon, Su-Yong; Kim, Jong-Chul; Choi, Buyng-Il

2008-01-01

Quartz crystal microbalance (QCM) dew-point sensors are based on frequency measurement, and so have fast response time, high sensitivity and high accuracy. Recently, we have reported that they have the very convenient attribute of being able to distinguish between supercooled dew and frost from a single scan through the resonant frequency of the quartz resonator as a function of the temperature. In addition to these advantages, by using three different types of heat sinks, we have developed a QCM dew/frost-point sensor with a very wide working temperature range (−90 °C to 15 °C). The temperature of the quartz surface can be obtained effectively by measuring the temperature of the quartz crystal holder and using temperature compensation curves (which showed a high level of repeatability and reproducibility). The measured dew/frost points showed very good agreement with reference values and were within ±0.1 °C over the whole temperature range

Measuring the diffraction properties of an imaging quartz(211) crystal

Energy Technology Data Exchange (ETDEWEB)

Haugh, M. J.; Jacoby, K. D.; Koch, J. A. [National Security Technologies, LLC, Livermore, California 94550 (United States); Chen, H.; Schneider, M. B. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States); Hill, K. W. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

2016-06-15

A dual goniometer X-ray system was used to measure the reflectivity curve for a spherically bent quartz(211) crystal. An analysis of the dual goniometer instrument response function for the rocking curve width measurement was developed and tested against the actual measurements. The rocking curve was measured at 4510.8 eV using the Ti Kα1 characteristic spectral line. The crystal is the dispersion element for a high resolution spectrometer used for plasma studies. It was expected to have a very narrow rocking curve width. The analysis showed that we could measure the upper bound for the rocking curve width of the Qz(211) crystal. The upper bound was 58 μrad giving a lower bound for the instrument resolving power E/ΔE = 34 000. Greatly improved insight into the dual goniometer operation and its limitations was achieved.

Preparation and characterization of ethylenediamine and cysteamine plasma polymerized films on piezoelectric quartz crystal surfaces for a biosensor

International Nuclear Information System (INIS)

Mutlu, Selma; Coekeliler, Dilek; Shard, Alex; Goktas, Hilal; Ozansoy, Berna; Mutlu, Mehmet

2008-01-01

This paper describes a method for the modification of quartz crystal surfaces to be used as a transducer in biosensors that allow recognition and quantification of certain biomolecules (antibodies, enzymes, proteins, etc). Quartz crystal sensors were modified by a plasma based electron beam generator in order to detect the level of the toxin histamine within biological liquids (blood, serum) and food (wine, cheese, fish etc.). Cysteamine and ethylenediamine were used as precursors in the plasma. After each modification step, the layers on the quartz crystal were characterized by frequency measurements. Modified surfaces were also characterized by contact angle, X-ray photoelectron spectroscopy and atomic force microscopy to determine the physical and chemical characteristics of the surfaces after each modification. Finally, the performance of the sensors were tested by the response to histamine via frequency shifts. The frequency shifts of the sensors prepared by plasma polymerization of ethylenediamine and cysteamine were approximately 3230 Hz and 5630 Hz, respectively, whereas the frequency change of the unmodified crystal surface was around 575 Hz

Lectin typing of Campylobacter jejuni using a novel quartz crystal microbalance technique

Energy Technology Data Exchange (ETDEWEB)

Yakovleva, Maria E., E-mail: maria.yakovleva@gmail.com [Department of Infectious Diseases and Medical Microbiology, Lund University, 223 62 Lund (Sweden); Moran, Anthony P. [Department of Microbiology, School of Natural Sciences, National University of Ireland, Galway (Ireland); Safina, Gulnara R. [Department of Analytical and Marine Chemistry, University of Gothenburg, 412 96 Gothenburg (Sweden); Wadstroem, Torkel [Department of Infectious Diseases and Medical Microbiology, Lund University, 223 62 Lund (Sweden); Danielsson, Bengt [Acromed Invest AB, Magistratsvaegen 10, 226 43 Lund (Sweden)

2011-05-23

Seven Campylobacter jejuni strains were characterised by a lectin typing assay. The typing system was based on a quartz crystal microbalance technique (QCM) with four commercially available lectins (wheat germ agglutinin, Maackia amurensis lectin, Lens culinaris agglutinin, and Concanavalin A), which were chosen for their differing carbohydrate specificities. Initially, the gold surfaces of the quartz crystals were modified with 11-mercaptoundecanoic acid followed by lectin immobilisation using a conventional amine-coupling technique. Bacterial cells were applied for lectin typing without preliminary treatment, and resonant frequency and dissipation responses were recorded. The adhesion of microorganisms on lectin surfaces was confirmed by atomic force microscopy. Scanning was performed in the tapping mode and the presence of bacteria on lectin-coated surfaces was successfully demonstrated. A significant difference in the dissipation response was observed for different C. jejuni strains which made it possible to use this parameter for discriminating between bacterial strains. In summary, the QCM technique proved a powerful tool for the recognition and discrimination of C. jejuni strains. The approach may also prove applicable to strain discrimination of other bacterial species, particularly pathogens.

Lectin typing of Campylobacter jejuni using a novel quartz crystal microbalance technique

International Nuclear Information System (INIS)

Yakovleva, Maria E.; Moran, Anthony P.; Safina, Gulnara R.; Wadstroem, Torkel; Danielsson, Bengt

2011-01-01

Seven Campylobacter jejuni strains were characterised by a lectin typing assay. The typing system was based on a quartz crystal microbalance technique (QCM) with four commercially available lectins (wheat germ agglutinin, Maackia amurensis lectin, Lens culinaris agglutinin, and Concanavalin A), which were chosen for their differing carbohydrate specificities. Initially, the gold surfaces of the quartz crystals were modified with 11-mercaptoundecanoic acid followed by lectin immobilisation using a conventional amine-coupling technique. Bacterial cells were applied for lectin typing without preliminary treatment, and resonant frequency and dissipation responses were recorded. The adhesion of microorganisms on lectin surfaces was confirmed by atomic force microscopy. Scanning was performed in the tapping mode and the presence of bacteria on lectin-coated surfaces was successfully demonstrated. A significant difference in the dissipation response was observed for different C. jejuni strains which made it possible to use this parameter for discriminating between bacterial strains. In summary, the QCM technique proved a powerful tool for the recognition and discrimination of C. jejuni strains. The approach may also prove applicable to strain discrimination of other bacterial species, particularly pathogens.

Electrochemistry, surface plasmon resonance, and quartz crystal microbalance: an associative study on cytochrome c adsorption on pyridine tail-group monolayers on gold.

Science.gov (United States)

Paulo, Tércio de F; de Sousa, Ticyano P; de Abreu, Dieric S; Felício, Nathalie H; Bernhardt, Paul V; Lopes, Luiz G de F; Sousa, Eduardo H S; Diógenes, Izaura C N

2013-07-25

Quartz crystal microbalance (QCM), surface plasmon resonance (SPR), and electrochemistry techniques were used to study the electron-transfer (ET) reaction of cytochrome c (Cyt c) on gold surfaces modified with thionicotinamide, thioisonicotinamide, 4-mercaptopyridine, 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol, 5-phenyl-1,3,4-oxadiazole-2-thiol, 4,4'-bipyridine, and 4,4'-dithiopyridine. The electrochemical results showed that the ET process is complex, being chiefly diffusional with steps depending on the orientation of the pyridine or phenyl tail group of the modifiers. The correlation between the electrochemical results and those acquired by SPR and QCM indicated the presence of an adlayer of Cyt c adsorbed on the thiolate SAMs. This adlayer, although being not electroactive, is essential to assess the ET reaction of Cyt c in solution. The results presented in this work are consistent with the statement (Feng, Z. Q.; Imabayashi, S.; Kakiuchi, T.; Niki, K. J. Electroanal. Chem. 1995, 394, 149-154) that the ET reaction of Cyt c can be explained in terms of the through-bond tunneling mechanism.

Electronic Nose using Gas Chromatography Column and Quartz Crystal Microbalance

Directory of Open Access Journals (Sweden)

Hari Agus Sujono

2011-08-01

Full Text Available The conventional electronic nose usually consists of an array of dissimilar chemical sensors such as quartz crystal microbalance (QCM combined with pattern recognition algorithm such as Neural network. Because of parallel processing, the system needs a huge number of sensors and circuits which may emerge complexity and inter-channel crosstalk problems. In this research, a new type of odor identification which combines between gas chromatography (GC and electronic nose methods has been developed. The system consists of a GC column and a 10-MHz quartz crystal microbalance sensor producing a unique pattern for an odor in time domain. This method offers advantages of substantially reduced size, interferences and power consumption in comparison to existing odor identification system. Several odors of organic compounds were introduced to evaluate the selectivity of the system. Principle component analysis method was used to visualize the classification of each odor in two-dimensional space. This system could resolve common organic solvents, including molecules of different classes (aromatic from alcohols as well as those within a particular class (methanol from ethanol and also fuels (premium from pertamax. The neural network can be taught to recognize the odors tested in the experiment with identification rate of 85 %. It is therefore the system may take the place of human nose, especially for poisonous odor evaluations.

Raman scattering by hot and thermal polaritons in crystal quartz

Energy Technology Data Exchange (ETDEWEB)

Bogani, F.; Colocci, M.; Neri, M.; Querzoli, R.

1984-11-01

Nonlinear mixing of IR and visible radiation, i.e. coherent Raman scattering by polaritons driven by a CO/sub 2/ laser, has been used to obtain the dispersion curve and its width in q-space of the polariton associated to the E-phonon at 1065 cm/sup -1/ in crystal quartz. It is shown in this paper that a direct method to determine independently, with high precision, the refractive index and absorbance of a crystal can be obtained in this way. The results are compared with accurate data obtained from Raman scattering by polaritions in thermal equilibrium and very good agreement is found between the two measurements. It is finally shown that nonlinear-mixing techniques turn out to be completely consistent with the simple picture of scattering of light by hot polaritons.

Power dependence on the rotational strength in a quartz crystal

International Nuclear Information System (INIS)

Joshi, N.V.; Salcedo, D.; Gil, H.

2007-01-01

The rotational strength of optical activity has been examined as a function of power of the incident radiation in a quartz crystal for the first time. It has been observed that the angle of rotation is proportional to the square root of the intensity of the radiation. The present experimental data directly support the recently proposed model which takes into account the electronic polarizability rather than the atomic polarizability. This model explicitly explains the role of the incident power in estimating the angle of rotation

Monitoring of morphology and physical properties of cultured cells using a micro camera and a quartz crystal with transparent indium tin oxide electrodes after injections of glutaraldehyde and trypsin

International Nuclear Information System (INIS)

Kang, Hyen-Wook; Ida, Kazumi; Yamamoto, Yuji; Muramatsu, Hiroshi

2008-01-01

For investigating the effects of chemical stimulation to cultured cells, we have developed a quartz crystal sensor system with a micro charge-coupled device (CCD) camera that enables microphotograph imaging simultaneously with quartz crystal measurement. Human hepatoma cell line (HepG2) cells were cultured on the quartz crystal through a collagen film. The electrode of the quartz crystal was made of indium tin oxide (ITO) transparent electrodes that enable to obtain a transparent mode photograph. Glutaraldehyde and trypsin were injected to the chamber of the cells, respectively. The response of the quartz crystal was monitored and microphotographs were recorded, and the resonance frequency and resonance resistance were analyzed with an F-R diagram that plotted the resonance frequency and resonance resistance. In the case of the glutaraldehyde injection, the cells responded in two steps that included the fast response of the cross-linking reaction and the successive internal change in the cells. In the case of the trypsin injection, the responses included two processes. In the first step, cell adhesion factors were cleaved and the cell structure became round, and in the next step, the cells were deposited on the quartz crystal surface and the surface of the cells was directly in contact with the quartz crystal surface

Acoustic loss and frequency stability studies of gamma- and proton-irradiated alpha-quartz crystal resonators

International Nuclear Information System (INIS)

Suter, J.J.

1988-01-01

This work examines the radiation-induced effects in alpha-quartz crystal resonators and distinguishes the various acoustic losses responsible for the frequency susceptibility over these dose ranges. Simulation of low-earth-orbit proton radiation was accomplished with protons from the Harvard University Cyclotron using a novel proton-beam modulator, which was designed to emulate a 10-120 MeV proton spectrum for the radiation susceptibility and acoustic-loss studies on AT quartz resonators. Quartz resonators having aluminum defect center concentrations between 0.01 and 19 ppm experienced proton-induced frequency shifts not correlated to their aluminum impurity content. It was also found that AT quartz resonators of the electrode-less BVA design experienced the smallest frequency shifts. Experiments conducted with 1.25-MeV gamma rays from a cobalt 60 source demonstrated identical frequency shifts in quartz, indicating that the energy losses of gamma rays and protons in quartz over the examined dose and energy ranges were similar. Acoustic-loss measurements conducted over the 0.3-70 K range revealed that the phonon-phonon and two-level energy excitation peaks near 20 and 5 K, respectively, were not affected by proton or cobalt 60 radiation

Electrochemical surface plasmon spectroscopy-Recent developments and applications

International Nuclear Information System (INIS)

Zhang, Nan; Schweiss, Ruediger; Zong, Yun; Knoll, Wolfgang

2007-01-01

A survey is given on recent developments and applications of electrochemical techniques combined with surface plasmon resonance (SPR) spectroscopy. Surface plasmon spectroscopy (SPS) and optical waveguide mode spectroscopy make use of evanescent waves on metal-dielectric interfaces and can be conveniently combined with electrochemical methods. Selected examples of applications of high-pressure surface electrochemical plasmon resonance spectroscopy to study supramolecular architectures such as layer-by-layer films of conducting polymers or thin composite films will be presented. Then a combination of SPS with the electrochemical quartz crystal microbalance (EQCM) will be introduced and illustrated with a study on doping/de-doping process of a conducting polymer. This combination allows for simultaneous electrochemical, optical and microgravimetric characterization of interfaces. Finally, new technical developments including integration of SPS into microfluidic devices using a grating coupler and surface plasmon enhanced diffraction will be discussed

A convenient tuning method for NMR/NQR spectrometers by using piezoelectric resonance from quartz crystals

International Nuclear Information System (INIS)

Yoon, J.G.; Yu, I.S.; Kwun, S.I.

1986-01-01

We observe that the cw or pulse NMR/NQR spectrometer tuning can be easily and conveniently adjusted by utilizing the piezoelectric resonance signal from quartz crystal sample. For an illustration some properties of the resonance signal are shown. (Author)

Low-cost scalable quartz crystal microbalance array for environmental sensing

Energy Technology Data Exchange (ETDEWEB)

Anazagasty, Cristain [University of Puerto Rico; Hianik, Tibor [Comenius University, Bratislava, Slovakia; Ivanov, Ilia N [ORNL

2016-01-01

Proliferation of environmental sensors for internet of things (IoT) applications has increased the need for low-cost platforms capable of accommodating multiple sensors. Quartz crystal microbalance (QCM) crystals coated with nanometer-thin sensor films are suitable for use in high-resolution (~1 ng) selective gas sensor applications. We demonstrate a scalable array for measuring frequency response of six QCM sensors controlled by low-cost Arduino microcontrollers and a USB multiplexer. Gas pulses and data acquisition were controlled by a LabVIEW user interface. We test the sensor array by measuring the frequency shift of crystals coated with different compositions of polymer composites based on poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) while films are exposed to water vapor and oxygen inside a controlled environmental chamber. Our sensor array exhibits comparable performance to that of a commercial QCM system, while enabling high-throughput 6 QCM testing for under $1,000. We use deep neural network structures to process sensor response and demonstrate that the QCM array is suitable for gas sensing, environmental monitoring, and electronic-nose applications.

Preparation and characterization of PTFE coating in new polymer quartz piezoelectric crystal sensor for testing liquor products

International Nuclear Information System (INIS)

Gu Yu; Li Qiang

2015-01-01

A new method was developed based on the electron beam vacuum dispersion (EBVD) technology to prepare the PTFE polymer coating of the new polymer quartz piezoelectric crystal sensor for testing liquor products. The new method was applied in the new EBVD equipment which we designed. A real-time system monitoring the polymer coating’s thickness was designed for the new EBVD equipment according to the quartz crystal microbalance (QCM) principle, playing an important role in preparing stable and uniform PTFE polymer coatings of the same thickness. 30 pieces of PTFE polymer coatings on the surface of the quartz crystal basis were prepared with the PTFE polymer ultrafine powder (purity ≥ 99.99%) as the starting material. We obtained 30 pieces of new PTFE polymer sensors. By using scanning electron microscopy (SEM), the structure of the PTFE polymer coating’s column clusters was studied. One sample from the 30 pieces of new PTFE polymer sensors was analysed by SEM in four scales, i.e., 400×, 1000×, 10000×, and 25000×. It was shown that under the condition of high bias voltage and low bias current, uniformly PTFE polymer coating could be achieved, which indicates that the new EBVD equipment is suitable for mass production of stable and uniform polymer coating. (paper)

Defect studies of ZnO single crystals electrochemically doped with hydrogen

Science.gov (United States)

Čížek, J.; Žaludová, N.; Vlach, M.; Daniš, S.; Kuriplach, J.; Procházka, I.; Brauer, G.; Anwand, W.; Grambole, D.; Skorupa, W.; Gemma, R.; Kirchheim, R.; Pundt, A.

2008-03-01

Various defect studies of hydrothermally grown (0001) oriented ZnO crystals electrochemically doped with hydrogen are presented. The hydrogen content in the crystals is determined by nuclear reaction analysis and it is found that already 0.3at.% H exists in chemically bound form in the virgin ZnO crystals. A single positron lifetime of 182ps is detected in the virgin crystals and attributed to saturated positron trapping at Zn vacancies surrounded by hydrogen atoms. It is demonstrated that a very high amount of hydrogen (up to ˜30at.%) can be introduced into the crystals by electrochemical doping. More than half of this amount is chemically bound, i.e., incorporated into the ZnO crystal lattice. This drastic increase of the hydrogen concentration is of marginal impact on the measured positron lifetime, whereas a contribution of positrons annihilated by electrons belonging to O-H bonds formed in the hydrogen doped crystal is found in coincidence Doppler broadening spectra. The formation of hexagonal shape pyramids on the surface of the hydrogen doped crystals by optical microscopy is observed and discussed.

Electroacoustic polymer microchip as an alternative to quartz crystal microbalance for biosensor development.

Science.gov (United States)

Gamby, Jean; Lazerges, Mathieu; Girault, Hubert H; Deslouis, Claude; Gabrielli, Claude; Perrot, Hubert; Tribollet, Bernard

2008-12-01

Laser photoablation of poly(ethylene terephthalate) (PET), a flexible dielectric organic polymer, was used to design an acoustic miniaturized DNA biosensor. The microchip device includes a 100-microm-thick PET layer, with two microband electrodes patterned in photoablated microchannels on one side and a depressed photoablated disk decorated by gold sputtered layer on the other side. Upon application of an electric signal between the two electrodes, an electroacoustic resonance phenomenon at approximately 30 MHz was established through the microelectrodes/PET/ gold layer interface. The electroacoustic resonance response was fitted with a series RLC motional arm in parallel with a static Co arm of a Buttlerworth-Van Dyke equivalent circuit: admittance spectra recorded after successive cycles of DNA hybridization on the gold surface showed reproducible changes on R, L, and C parameters. The same hybridizations runs were performed concomitantly on a 27-MHz (9 MHz, third overtone) quartz crystal microbalance in order to validate the PET device developed for bioanalysis applications. The electroacoustic PET device, approximately 100 times smaller than a microbalance quartz crystal, is interesting for the large-scale integration of acoustic sensors in biochips.

Electrochemical quartz crystal impedance study on immobilization of glucose oxidase in a polymer grown from dopamine oxidation at an Au electrode for glucose sensing

International Nuclear Information System (INIS)

Li Mingrui; Deng Chunyan; Xie Qingji; Yang Yang; Yao Shouzhuo

2006-01-01

Glucose oxidase (GOD) was codeposited into a polymer grown from oxidation of dopamine (DA) at an Au electrode in a neutral phosphate aqueous solution for the first time. The electrochemical quartz crystal impedance analysis (EQCIA) method was used to monitor the GOD-immobilization process. Effects of concentrations of phosphate buffer, DA and GOD were investigated, and the optimal concentrations were found to be 20.0mM phosphate buffer (pH 7.0), 30.0mM DA and 5.00mgml -1 GOD. A glucose biosensor was thus constructed, and effects of various experimental parameters on the sensor performance, including applied potential, solution pH and electroactive interferents, were examined. At an optimal potential of 0.6V versus the KCl-saturated calomel electrode (SCE), the current response of the biosensor in the selected phosphate buffer (pH 7.0) was linear with the concentration of glucose from 0.05 to 9mM, with a lower detection limit of 3μM (S/N=3), short response time (within 15s) and good anti-interferent ability. The Michaelis constant (K m app ) was estimated to be 9.6mM. The biosensor exhibited good storage stability, i.e. 96% of its initial response was retained after 7-day storage in the selected phosphate buffer at 4deg. C, and even after another 3 weeks the biosensor retained 86% of its initial response. In addition, the enzymatic specific activity and enzymatic relative activity of the GOD immobilized in the polymer from dopamine oxidation (PFDO) were estimated from the EQCIA method to be 1.43kUg -1 and 3.7%, respectively, which were larger than the relevant values obtained experimentally using poly(o-aminophenol) and poly(N-methylpyrrole) matrices, suggesting that the PFDO is a better matrix to immobilize GOD

Use of the quartz crystal microbalance to determine the monomeric friction coefficient of polyimides

Science.gov (United States)

Bechtold, Mary M.

1995-01-01

When a thin film of polymer is coated on to a quartz crystal microbalance (QCM), the QCM can be used to detect the rate of increase in weight of the polymer film as the volatile penetrant diffuses into the polymer. From this rate information the diffusion coefficient of the penetrant into the polymer can be computed. Calculations requiring this diffusion coefficient lead to values which approximate the monomeric friction coefficient of the polymer. This project has been concerned with the trial of crystal oscillating circuits suitable for driving polymer coated crystals in an atmosphere of penetrant. For these studies done at room temperature, natural rubber was used as an easily applied polymer that is readily penetrated by toluene vapors, qualities anticipated with polyimides when they are tested at T(g) in the presence of toluene. Three quartz crystal oscillator circuits were tested. The simplest circuit used +/- 5 volt dc and had a transistor to transistor logic (TTL) inverter chip that provides a 180 deg phase shift via a feed back loop. This oscillator circuit was stable but would not drive the crystal when the crystal was coated with polymer and subjected to toluene vapors. Removal of a variable resistor from this circuit increased stability but did not otherwise increase performance. Another driver circuit tested contained a two stage differential input, differential output, wide band video amplifier and also contain a feed back loop. The circuit voltage could not be varied and operated at +/- 5 volts dc; this circuit was also stable but failed to oscillate the polymer coated crystal in an atmosphere saturated with toluene vapors. The third oscillator circuit was of similar construction and relied on the same video amplifier but allowed operation with variable voltage. This circuit would drive the crystal when the crystal was submerged in liquid toluene and when the crystal was coated with polymer and immersed in toluene vapors. The frequency readings

Data analysis for lidar and quartz crystal microbalance systems

Science.gov (United States)

Kent, G. S.; Deepak, A.

1985-01-01

Results are presented of the analysis of data taken on the stratospheric aerosol, using lidar, Quartz Crystal Microbalance (QCM), and the SAGE and SAM II satellite systems. The main objective of the work reported has been to use the data, taken with the NASA-LaRC instruments to study the stratospheric effects of volcanic eruptions during the period between the launch of the SAGE and SAM II satellite systems and October 1980. Four significant volcanic eruptions, for which data are available, occurred during this period--Soufriere, Sierra Negra, Mt. St. Helens, and Ulawun. Data on these have been analyzed to determine the changes in stratospheric mass loading produced by the eruptions, and to study the dispersion of the newly injected material.

Probing absorption of deuterium into palladium cathodes during D2O electrolysis with an in situ electrochemical microbalance technique

International Nuclear Information System (INIS)

Oyama, Noboru; Yamamoto, Nobushige; Hatozaki, Osamu; Ohsaka, Takeo

1990-01-01

The in situ observation of the absorption of deuterium (or hydrogen) into the Pd cathode during D 2 O (or H 2 O) electrolysis was made by an electrochemical microbalance technique which is based on the quartz-crystal electrode. The resonant frequency of the Pd-coated quartz-crystal electrode decreased with increasing amount of charge passed during electrolysis, and the frequency change for the D 2 O electrolysis was about twice that for the H 2 O electrolysis. The atom ratios of H/Pd and D/Pd of the H-Pd and D-Pd compounds resulting from the electrolysis were estimated to be 0.59 and 0.57, respectively. (author)

Experimental study of quartz inclusions in garnet at pressures up to 3.0 GPa: evaluating validity of the quartz-in-garnet inclusion elastic thermobarometer

Science.gov (United States)

Thomas, Jay B.; Spear, Frank S.

2018-05-01

Garnet crystals with quartz inclusions were hydrothermally crystallized from oxide starting materials in piston-cylinder apparatuses at pressures from 0.5 to 3 GPa and temperatures ranging from 700 to 800 °C to study how entrapment conditions affect remnant pressures of quartz inclusions used for quartz-in-garnet (QuiG) elastic thermobarometry. Systematic changes of the 128, 206 and 464 cm-1 Raman band frequencies of quartz were used to determine pressures of quartz inclusions in garnet using Raman spectroscopy calibrations that describe the P-T dependencies of Raman band shifts for quartz under hydrostatic pressure. Within analytical uncertainties, inclusion pressures calculated for each of the three Raman band frequencies are equivalent, which suggests that non-hydrostatic stress effects caused by elastic anisotropy in quartz are smaller than measurement errors. The experimental quartz inclusions have pressures ranging from - 0.351 to 1.247 GPa that span the range of values observed for quartz inclusions in garnets from natural rocks. Quartz inclusion pressures were used to model P-T conditions at which the inclusions could have been trapped. The accuracy of QuiG thermobarometry was evaluated by considering the differences between pressures measured during experiments and pressures calculated using published equation of state parameters for quartz and garnet. Our experimental results demonstrate that Raman measurements performed at room temperature can be used without corrections to estimate garnet crystallization pressures. Calculated entrapment pressures for quartz inclusions in garnet are less than 10% different from pressures measured during the experiments. Because the method is simple to apply with reasonable accuracy, we expect widespread usage of QuiG thermobarometry to estimate crystallization conditions for garnet-bearing silicic rocks.

SHORT COMMUNICATION: Recognition of supercooled dew in a quartz crystal microbalance dew-point sensor by slip phenomena

Science.gov (United States)

Kwon, Su-Yong; Kim, Jong-Chul; Choi, Byung-Il

2007-10-01

Distinguishing between a supercooled dew and frost below 0 °C in dew/frost-point measurements is an important and challenging problem that has not yet been completely solved. This study presents a new method for the recognition of a supercooled dew in a dew/frost-point sensor. A quartz crystal microbalance (QCM) sensor was used as a dew/frost-point sensor to detect a dew and a supercooled dew as well as frost. The slip phenomenon occurring at an interface between the water droplet and the surface of the quartz crystal resonator of the QCM sensor gives a simple and accurate way of distinguishing between a supercooled dew and frost below 0 °C. This method can give a highly accurate measurement of the dew or the frost point without misreading in the dew-point sensor at temperatures below 0 °C.

A STUDY OF THE PRESSURE SOLUTION AND DEFORMATION OF QUARTZ CRYSTALS AT HIGH pH AND UNDER HIGH STRESS

Directory of Open Access Journals (Sweden)

JUNG-HAE CHOI

2013-02-01

Full Text Available Bentonite is generally used as a buffer material in high-level radioactive waste disposal facilities and consists of 50% quartz by weight. Quartz strongly affects the behavior of bentonite over very long periods. For this reason, quartz dissolution experiment was performed under high-pressure and high-alkalinity conditions based on the conditions found in a high-level radioactive waste disposal facility located deep underground. In this study, two quartz dissolution experiments were conducted on 1 quartz beads under low-pressure and high-alkalinity conditions and 2 a single quartz crystal under high-pressure and high-alkalinity conditions. Following the experiments, a confocal laser scanning microscope (CLSM was used to observe the surfaces of experimental samples. Numerical analyses using the finite element method (FEM were also performed to quantify the deformation of contact area. Quartz dissolution was observed in both experiments. This deformation was due to a concentrated compressive stress field, as indicated by the quartz deformation of the contact area through the FEM analysis. According to the numerical results, a high compressive stress field acted upon the neighboring contact area, which showed a rapid dissolution rate compared to other areas of the sample.

Colorado quartz: occurrence and discovery

Science.gov (United States)

Kile, D.E.; Modreski, P.J.; Kile, D.L.

1991-01-01

The many varieties and associations of quartz found throughout the state rank it as one of the premier worldwide localities for that species. This paper briefly outlines the historical importance of the mineral, the mining history and the geological setting before discussing the varieties of quartz present, its crystallography and the geological enviroments in which it is found. The latter include volcanic rocks and near surface igneous rocks; pegmatites; metamorphic and plutonic rocks; hydrothermal veins; skarns and sedimentary deposits. Details of the localities and mode of occurrence of smoky quartz, amethyst, milky quartz, rock crystal, rose quartz, citrine, agate and jasper are then given. -S.J.Stone

Fabrication of a novel quartz micromachined gyroscope

Science.gov (United States)

Xie, Liqiang; Xing, Jianchun; Wang, Haoxu; Wu, Xuezhong

2015-04-01

A novel quartz micromachined gyroscope is proposed in this paper. The novel gyroscope is realized by quartz anisotropic wet etching and 3-dimensional electrodes deposition. In the quartz wet etching process, the quality of Cr/Au mask films affecting the process are studied by experiment. An excellent mask film with 100 Å Cr and 2000 Å Au is achieved by optimization of experimental parameters. Crystal facets after etching seriously affect the following sidewall electrodes deposition process and the structure's mechanical behaviours. Removal of crystal facets is successfully implemented by increasing etching time based on etching rate ratios between facets and crystal planes. In the electrodes deposition process, an aperture mask evaporation method is employed to prepare electrodes on 3-dimensional surfaces of the gyroscope structure. The alignments among the aperture masks are realized by the ABM™ Mask Aligner System. Based on the processes described above, a z-axis quartz gyroscope is fabricated successfully.

In-Line Measurement of Water Content in Ethanol Using a PVA-Coated Quartz Crystal Microbalance

Directory of Open Access Journals (Sweden)

Byoung Chul Kim

2014-01-01

Full Text Available An in-line device for measuring the water content in ethanol was developed using a polyvinyl alcohol (PVA-coated quartz crystal microbalance. Bio-ethanol is widely used as the replacement of gasoline, and its water content is a key component of its specifications. When the PVA-coated quartz crystal microbalance is contacted with ethanol containing a small amount of water, the water is absorbed into the PVA increasing the load on the microbalance surface to cause a frequency drop. The determination performance of the PVA-coated microbalance is examined by measuring the frequency decreases in ethanol containing 2% to 10% water while the ethanol flows through the measurement device. The measurements indicates that the higher water content is the more the frequency reduction is, though some deviation in the measurements is observed. This indicates that the frequency measurement of an unknown concentration of water in ethanol can be used to determine the water content in ethanol. The PVA coating is examined by microscopy and FTIR (Fourier transform infrared spectroscopy.

Simultaneous detection of surface coverage and structure of krypton films on gold by helium atom diffraction and quartz crystal microbalance techniques.

Science.gov (United States)

Danışman, M Fatih; Özkan, Berrin

2011-11-01

We describe a quartz crystal microbalance setup that can be operated at low temperatures in ultra high vacuum with gold electrode surfaces acting as substrate surface for helium diffraction measurements. By simultaneous measurement of helium specular reflection intensity from the electrode surface and resonance frequency shift of the crystal during film adsorption, helium diffraction data can be correlated to film thickness. In addition, effects of interfacial viscosity on the helium diffraction pattern could be observed. To this end, first, flat gold films on AT cut quartz crystals were prepared which yield high enough helium specular reflection intensity. Then the crystals were mounted in the helium diffractometer sample holder and driven by means of a frequency modulation driving setup. Different crystal geometries were tested to obtain the best quality factor and preliminary measurements were performed on Kr films on gold surfaces. While the crystal structure and coverage of krypton films as a function of substrate temperature could successfully be determined, no depinning effects could be observed. © 2011 American Institute of Physics

Phase transition of pNIPAM grafted on plasma-activated PEO monitored in-situ by quartz crystal microbalance

Energy Technology Data Exchange (ETDEWEB)

Heinz, P; Bretagnol, F; Mannelli, I; Gillil, D; Rauscher, H; Rossi, F [European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (Vatican City State, Holy See,) (Italy)], E-mail: hubert.rauscher@jrc.it

2008-03-15

Thermoresponsive poly(N-isopropylacrylamide) layers were grafted on plasma-activated poly(ethylene oxide)-like substrate. Analysis by ToF-SIMS confirmed the presence of a pNIPAM film, which shows a phase transition temperature at 28 - 32 deg. C with hysteresis, as determined in-situ by quartz crystal microbalance. During the transition, the frequency of the pNIPAM coated quartz sensor exhibits a pronounced and unexpected minimum while the dissipation changes monotonously. This peculiar behaviour is explained by temporary formation of water-rich regions, which may cause delayed release and uptake of water during the collapse and re-swelling of the layer.

Phase transition of pNIPAM grafted on plasma-activated PEO monitored in-situ by quartz crystal microbalance

International Nuclear Information System (INIS)

Heinz, P; Bretagnol, F; Mannelli, I; Gillil, D; Rauscher, H; Rossi, F

2008-01-01

Thermoresponsive poly(N-isopropylacrylamide) layers were grafted on plasma-activated poly(ethylene oxide)-like substrate. Analysis by ToF-SIMS confirmed the presence of a pNIPAM film, which shows a phase transition temperature at 28 - 32 deg. C with hysteresis, as determined in-situ by quartz crystal microbalance. During the transition, the frequency of the pNIPAM coated quartz sensor exhibits a pronounced and unexpected minimum while the dissipation changes monotonously. This peculiar behaviour is explained by temporary formation of water-rich regions, which may cause delayed release and uptake of water during the collapse and re-swelling of the layer

Radiation defect production in quartz crystals with various structure perfectness degree; Radiatsionnoe defektoobrazovanie v kristallakh kvartsa s razlichnoj stepen`yu sovershenstva struktury

Energy Technology Data Exchange (ETDEWEB)

Khushvakov, O B

1992-01-01

Radiation defects production processes in pure and doped quartz crystals with various structure defectness, caused by preliminary irradiation with neutrons, protons, deuterons and {alpha}-particles, during various electron excitation densities were investigated. The distribution of colour centres along the thickness of irradiated quartz crystals was measured. It was supposed that colour centres are produced on account of inelastic energy losses as the result of collective decay of two or more interacting excitons. It was shown that in quartz crystals under the actions of protons with overthreshold energy 18 MeV and electrons with subthreshold energy 100 keV the same structure defects are formed. It was established that radiation defect production process has two stages. The first stage reveals radiation defects produced by preliminary irradiation. The second one reveals additional intrinsic defects formed under the action of gamma-rays and electrons. The probability dependence of defect production on neutron fluence and masses of incident particles was studied. It was supposed that the creation of additional defects in preliminary irradiated crystals is due to non-radiative decay of electron excitations near radiation-induced defects. It was shown that increase of impurity concentration leads to rate growth of accumulation of radiation induced defects. (A.A.D.) 15 refs. 4 figs.

Improvement of the thickness distribution of a quartz crystal wafer by numerically controlled plasma chemical vaporization machining

International Nuclear Information System (INIS)

Shibahara, Masafumi; Yamamura, Kazuya; Sano, Yasuhisa; Sugiyama, Tsuyoshi; Endo, Katsuyoshi; Mori, Yuzo

2005-01-01

To improve the thickness uniformity of thin quartz crystal wafer, a new machining process that utilizes an atmospheric pressure plasma was developed. In an atmospheric pressure plasma process, since the kinetic energy of ions that impinge to the wafer surface is small and the density of the reactive species is large, high-efficiency machining without damage is realized, and the thickness distribution is corrected by numerically controlled scanning of the quartz wafer to the localized high-density plasma. By using our developed machining process, the thickness distribution of an AT cut wafer was improved from 174 nm [peak to valley (p-v)] to 67 nm (p-v) within 94 s. Since there are no unwanted spurious modes in the machined quartz wafer, it was proved that the developed machining method has a high machining efficiency without any damage

Functional Durability of a Quartz Crystal Microbalance Sensor for the Rapid Detection of Salmonella in Liquids from Poultry Packaging

National Research Council Canada - National Science Library

Olsen, Eric

2000-01-01

.... A rapid, sensitive (350 +/- 150 cells ml/cm) quartz crystal microbalance biosensor, layered with heat-treated anti-Salmonella-phospholipid monolayers by the Langmuir-Blodgett technique, has been evaluated by immersion testing in chicken exudate...

Biomimetic piezoelectric quartz crystal sensor with chloramphenicol-imprinted polymer sensing layer.

Science.gov (United States)

Ebarvia, Benilda S; Ubando, Isaiah E; Sevilla, Fortunato B

2015-11-01

The measurement of banned antibiotic like chloramphenicol is significant for customer protection and safety. The presence of residual antibiotics in foods and food products of animal origin could pose as health hazards and affect food quality for global acceptance. In this study, the potential of a chloramphenicol sensor based on molecularly imprinted polymer (MIP) coupled with a piezoelectric quartz crystal was explored. The MIP was prepared by precipitation polymerization at 60 °C. Methacrylic acid was used as monomer, trimethylolpropane trimethacrylate (TRIM) as crosslinker, and chloramphenicol as the template. Template removal on the resulting polymer was done by extraction using methanol-acetic acid. Characterization of the MIP and NIP were conducted by spectroscopic and microscopic methods. These further supported the imprinting and rebinding process of chloramphenicol to the polymer matrix. The chloramphenicol sensor was devised by spin-coating onto one side of the 10 MHz AT-cut quartz crystal the MIP suspension in polyvinylchloride-tetrahydrofuran (6:2:1 w/w/v) solution. Optimization of sensor response was performed by varying the type of cross-linker, amount of MIP sensing layer, curing time, and pH. The sensor exhibited good sensitivity of about 73 Hz/log (conc., µg mL(-1)) and good repeatability (rsd<10%). A linear relationship (r(2)=0.9901) between frequency shift and chloramphenicol concentration in the range of 1×10(-6) up to 1×10(-1) µg/mL was obtained. The sensor response was highly selective to chloramphenicol than with other compounds of similar chemical structures. Acceptable percent recovery was obtained for real sample analysis using the sensor. The proposed sensor could be a promising low cost and highly sensitive approach for residual chloramphenicol quantification in food products. Copyright © 2015 Elsevier B.V. All rights reserved.

Polyacrylonitrile Nanofiber-Based Quartz Crystal Microbalance for Sensitive Detection of Safrole

Directory of Open Access Journals (Sweden)

Aditya Rianjanu

2018-04-01

Full Text Available Safrole is the main precursor for producing the amphetamine-type stimulant (ATS drug, N-methyl-3,4-methylenedioxyamphetamine (MDMA, also known as ecstasy. We devise a polyacrylonitrile (PAN nanofiber-based quartz crystal microbalance (QCM for detecting safrole. The PAN nanofibers were fabricated by direct electrospinning to modify the QCM chips. The PAN nanofiber on the QCM chips has a diameter of 240 ± 10 nm. The sensing of safrole by QCM modified with PAN nanofiber shows good reversibility and an apparent sensitivity of 4.6 Hz·L/mg. The proposed method is simple, inexpensive, and convenient for detecting safrole, and can be an alternative to conventional instrumental analytical methods for general volatile compounds.

Dew point fast measurement in organic vapor mixtures using quartz resonant sensor

Science.gov (United States)

Nie, Jing; Liu, Jia; Meng, Xiaofeng

2017-01-01

A fast dew point sensor has been developed for organic vapor mixtures by using the quartz crystal with sensitive circuits. The sensor consists of the quartz crystal and a cooler device. Proactive approach is taken to produce condensation on the surface of the quartz crystal, and it will lead to a change in electrical features of the quartz crystal. The cessation of oscillation was measured because this phenomenon is caused by dew condensation. Such a phenomenon can be used to detect the dew point. This method exploits the high sensitivity of the quartz crystal but without frequency measurement and also retains the stability of the resonant circuit. It is strongly anti-interfered. Its performance was evaluated with acetone-methanol mixtures under different pressures. The results were compared with the dew points predicted from the universal quasi-chemical equation to evaluate the performance of the proposed sensor. Though the maximum deviations of the sensor are less than 1.1 °C, it still has a fast response time with a recovery time of less than 10 s, providing an excellent dehumidifying performance.

The coexistence of pressure waves in the operation of quartz-crystal shear-wave sensors

OpenAIRE

Reddy, SM; Jones, JP; Lewis, TJ

1998-01-01

It is demonstrated that an AT-cut quartz crystal driven in the thickness-shear-wave mode and typically used as a sensor to monitor the viscoelastic shear-wave properties of a fluid also produce longitudinal pressure waves. Unlike the shear wave, these waves are capable of long-range propagation through the fluid and of reflection at its boundaries, notably at an outer fluid–air interface. They introduce a component into the measured electrical impedance and resonance frequency shift of the cr...

Respiratory Monitoring by Porphyrin Modified Quartz Crystal Microbalance Sensors

Directory of Open Access Journals (Sweden)

Seung-Woo Lee

2011-01-01

Full Text Available A respiratory monitoring system based on a quartz crystal microbalance (QCM sensor with a functional film was designed and investigated. Porphyrins 5,10,15,20-tetrakis-(4-sulfophenyl-21H,23H-porphine (TSPP and 5,10,15,20-tetrakis-(4-sulfophenyl-21H, 23H-porphine manganese (III chloride (MnTSPP used as sensitive elements were assembled with a poly(diallyldimethyl ammonium chloride (PDDA. Films were deposited on the QCM resonators using layer-by-layer method in order to develop the sensor. The developed system, in which the sensor response reflects lung movements, was able to track human respiration providing respiratory rate (RR and respiratory pattern (RP. The sensor system was tested on healthy volunteers to compare RPs and calculate RRs. The operation principle of the proposed system is based on the fast adsorption/desorption behavior of water originated from human breath into the sensor films deposited on the QCM electrode.

Investigation of planar channeling radiation on diamond and quartz crystals at electron energies between 14 and 34 MeV and probing the influence of ultrasonic waves on channeling radiation

International Nuclear Information System (INIS)

Azadegan, B.

2007-01-01

Measurements of planar channeling radiation (CR) have been performed at the electron beam of ELBE within an energy range between 14 and 34 MeV and for thicknesses of the diamond crystals between 42.5 and 500 μm. Absolute CR photon yields have for the first time been obtained for the above given ranges of electron energy and crystal thickness. The square-root dependence of the planar CR photon yield on the thickness of diamond crystals has been confirmed. A systematic quantitative investigation of the influence of the crystal thickness on the CR line shape has for the first time been performed. The mean-squared multiple-scattering angle effective for planar CR observed in forward direction has been found to be weaker as assumed from scattering in amorphous targets. Scaling laws deduced from the measured CR data are of advantage for the operation of a CR source. The second part of this thesis deals with the possibility of stimulation of CR emission by means of ultrasonic vibrations excited in a piezoelectric single crystal. Since the knowledge of the CR spectra generated on undisturbed quartz crystals is a necessary precondition for some investigation of the influence of US, planar CR has for the first time been measured at medium electron energies for a variety of planes in quartz. As a consequence of the hexagonal structure of this crystal, relative intense CR could be registered even out of planes with indices larger than one. On the base of the non-linear optics method, occupation functions and spectral distributions of planar CR have been calculated for channeling of 20 MeV electrons in the (01 anti 15) plane of a 20 μm thick quartz crystal at resonant influence of ultrasound (US). The resonance frequencies have been deduced from the measurements of CR spectra performed on quartz. First experimental investigations of the influence of US on CR started at ELBE aimed at the study of the effect of non-resonant ultrasonic vibrations excited in a 500 μm thick

Investigation of planar channeling radiation on diamond and quartz crystals at electron energies between 14 and 34 MeV and probing the influence of ultrasonic waves on channeling radiation

Energy Technology Data Exchange (ETDEWEB)

Azadegan, B.

2007-11-15

Measurements of planar channeling radiation (CR) have been performed at the electron beam of ELBE within an energy range between 14 and 34 MeV and for thicknesses of the diamond crystals between 42.5 and 500 {mu}m. Absolute CR photon yields have for the first time been obtained for the above given ranges of electron energy and crystal thickness. The square-root dependence of the planar CR photon yield on the thickness of diamond crystals has been confirmed. A systematic quantitative investigation of the influence of the crystal thickness on the CR line shape has for the first time been performed. The mean-squared multiple-scattering angle effective for planar CR observed in forward direction has been found to be weaker as assumed from scattering in amorphous targets. Scaling laws deduced from the measured CR data are of advantage for the operation of a CR source. The second part of this thesis deals with the possibility of stimulation of CR emission by means of ultrasonic vibrations excited in a piezoelectric single crystal. Since the knowledge of the CR spectra generated on undisturbed quartz crystals is a necessary precondition for some investigation of the influence of US, planar CR has for the first time been measured at medium electron energies for a variety of planes in quartz. As a consequence of the hexagonal structure of this crystal, relative intense CR could be registered even out of planes with indices larger than one. On the base of the non-linear optics method, occupation functions and spectral distributions of planar CR have been calculated for channeling of 20 MeV electrons in the (01 anti 15) plane of a 20 {mu}m thick quartz crystal at resonant influence of ultrasound (US). The resonance frequencies have been deduced from the measurements of CR spectra performed on quartz. First experimental investigations of the influence of US on CR started at ELBE aimed at the study of the effect of non-resonant ultrasonic vibrations excited in a 500 {mu}m thick

Study of the electrodeposition of rhenium thin films by electrochemical quartz microbalance and X-ray photoelectron spectroscopy

International Nuclear Information System (INIS)

Schrebler, R.; Cury, P.; Suarez, C.; Munoz, E.; Vera, F.; Cordova, R.; Gomez, H.; Ramos-Barrado, J.R.; Leinen, D.; Dalchiele, E.A.

2005-01-01

Rhenium thin films were prepared by electrodeposition from an aqueous solution containing 0.1 M Na 2 SO 4 +H 2 SO 4 , pH 2 in presence of y mM HReO 4 . As substrates polycrystalline gold (y=0.75 mM HReO 4 ) and monocrystalline n-Si(100) (y=40 mM HReO 4 ) were used. The electrochemical growth of rhenium was studied by cyclic voltammetry and electrochemical quartz microbalance on gold electrodes. The results found in the potential region before the hydrogen evolution reaction (her) showed that ReO 3 , ReO 2 and Re 2 O 3 with different hydration grades can be formed. In the potential region where the her is occurring, either on gold or n-Si(100) the electrodeposition of metallic rhenium takes place. On both substrates, rhenium films were formed by electrolysis at constant potential and X-ray photoelectron spectroscopy technique was used to characterise these deposits. It was concluded that the electrodeposited films were of metallic rhenium and only the uppermost atomic layer contained rhenium oxide species

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.

Ferrobielastic twinning in irradiated quartz

International Nuclear Information System (INIS)

Shiau, S.M.

1986-01-01

Cultured quartz is usually free from electrical twinning; however, it may occur if the seed crystal is twinned or if undue applied forces are exerted on the crystal. Ferrobielastic twinning was studied optically (photoelastic effect) and electrically (piezoelectric effect). At room temperature, twins were perceptible at stresses of about 2.l5 x 10 8 N/m 2 , and crystals switched from their original states to the alternative twin states at stresses about 5.0 x 10 8 N/m 2 (called coercive stress). The decrease in coercive stress with increasing temperature was observed, and these coercive stresses become very low as temperatures reach to 300 0 C. The effects of irradiation on the twinning in quartz were also studied. The presence of defects produced by irradiation was utilized to pin the domain wall motion. Both neutrons and gamma rays were employed. The stress required to nucleate an appreciable volume of twins is about twice as high for irradiated crystals than for those unirradiated. This result demonstrated that the irradiated crystals can tolerate higher stresses. However, the coercive stress for complete switch-over was not much different for irradiated and unirradiated crystals. It appears that the defects caused by irradiation eliminate the initial twinning events but do not affect switch-over

Quartz Crystal Microbalance: A tool for analyzing loss of volatile compounds, gas sorption, and curing kinetics

Energy Technology Data Exchange (ETDEWEB)

Bajric, Sendin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-03-16

Los Alamos National Laboratory (LANL) has recently procured a quartz crystal microbalance (QCM). Current popular uses are biological sensors, surface chemistry, and vapor detection. LANL has projects related to analyzing curing kinetics, measuring gas sorption on polymers, and analyzing the loss of volatile compounds in polymer materials. The QCM has yet to be employed; however, this review will cover the use of the QCM in these applications and its potential.

Hydrogen speciation in synthetic quartz

Science.gov (United States)

Aines, R.D.; Kirby, S.H.; Rossman, G.R.

1984-01-01

The dominant hydrogen impurity in synthetic quartz is molecular H2O. H-OH groups also occur, but there is no direct evidence for the hydrolysis of Si-O-Si bonds to yield Si-OH HO-Si groups. Molecular H2O concentrations in the synthetic quartz crystals studied range from less than 10 to 3,300 ppm (H/Si), and decrease smoothly by up to an order of magnitude with distance away from the seed. OH- concentrations range from 96 to 715 ppm, and rise smoothly with distance away from the seed by up to a factor of three. The observed OH- is probably all associated with cationic impurities, as in natural quartz. Molecular H2O is the dominant initial hydrogen impurity in weak quartz. The hydrolytic weakening of quartz may be caused by the transformation H2O + Si-O-Si ??? 2SiOH, but this may be a transitory change with the SiOH groups recombining to form H2O, and the average SiOH concentration remaining very low. Synthetic quartz is strengthened when the H2O is accumulated into fluid inclusions and cannot react with the quartz framework. ?? 1984 Springer-Verlag.

Study on pivot-point vibration of molecular bond-rupture events by quartz crystal microbalance for biomedical diagnostics

Directory of Open Access Journals (Sweden)

Yuan YJ

2012-01-01

Full Text Available Yong J Yuan, Renjie JiaLaboratory of Biosensing and MicroMechatronics, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan, People's Republic of ChinaAbstract: Bond-rupture scanning for biomedical diagnostics is examined using quartz crystal microbalance (QCM experiments and microparticle mechanics modeling calculations. Specific and nonspecific interactions between a microparticle and its binding QCM surface can be distinguished by gradually increasing the amplitude of driving voltage applied to QCM and monitoring its frequency changes. This research proposes a mechanical model of interactions between biological molecules and a QCM substrate surface. The mechanical force required to break a biotin–streptavidin bond was calculated through a one-pivot-point bottom-up vibration model. The bond-rupture force increases with an increase of the microparticle radius, the QCM resonant frequency, and the amplitude of driving voltage applied to the QCM. The significance of the research on biological molecular bond rupture is extremely important in characterizing microbial (such as cells and virus specificity, due to the force magnitude needed to break bonds using a transducer.Keywords: bond rupture, mechanical force, biomolecular binding energy spectra, quartz crystal microbalance (QCM

Towards vibrational spectroscopy on surface-attached colloids performed with a quartz crystal microbalance

Directory of Open Access Journals (Sweden)

Diethelm Johannsmann

2016-12-01

Full Text Available Colloidal spheres attached to a quartz crystal microbalance (QCM produce the so-called “coupled resonances”. They are resonators of their own, characterized by a particle resonance frequency, a resonance bandwidth, and a modal mass. When the frequency of the main resonator comes close to the frequency of the coupled resonance, the bandwidth goes through a maximum. A coupled resonance can be viewed as an absorption line in acoustic shear-wave spectroscopy. The known concepts from spectroscopy apply. This includes the mode assignment problem, selection rules, and the oscillator strength. In this work, the mode assignment problem was addressed with Finite Element calculations. These reveal that a rigid sphere in contact with a QCM displays two modes of vibration, termed “slipping” and “rocking”. In the slipping mode, the sphere rotates about its center; it exerts a tangential force onto the resonator surface at the point of contact. In the rocking mode, the sphere rotates about the point of contact; it exerts a torque onto the substrate. In liquids, both axes of rotation are slightly displaced from their ideal positions. Characteristic for spectroscopy, the two modes do not couple to the mechanical excitation equally well. The degree of coupling is quantified by an oscillator strength. Because the rocking mode mostly exerts a torque (rather than a tangential force, its coupling to the resonator's tangential motion is weak; the oscillator strength consequently is small. Recent experiments on surface-adsorbed colloidal spheres can be explained by the mode of vibration being of the rocking type. Keywords: Quartz crystal microbalance, Coupled resonance, Biocolloids, Adsorption

Using Quartz Crystal Microbalance for Field Measurement of Liquid Viscosities

Directory of Open Access Journals (Sweden)

Qingsong Bai

2016-01-01

Full Text Available The field measurement of liquid viscosities, especially the high viscous liquids, is challenging and often requires expensive equipment, long processing time, and lots of reagent. We use quartz crystal microbalances (QCMs operating in solution which are also sensitive to the viscosity and density of the contacting solution. QCMs are typically investigated for sensor applications in which one surface of QCM completely immersed in Newtonian liquid, but the viscous damping in liquids would cause not only large frequency shifts but also large losses in the quality factor Q leading to instability and even cessation of oscillation. A novel mass-sensitivity-based method for field measurement of liquid viscosities using a QCM is demonstrated in this paper and a model describing the influence of the liquid properties on the oscillation frequency is established as well. Two groups of verified experiments were performed and the experimental results show that the presented method is effective and possesses potential applications.

Quartz crystal microbalance-based system for high-sensitivity differential sputter yield measurements

International Nuclear Information System (INIS)

Rubin, B.; Topper, J. L.; Farnell, C. C.; Yalin, A. P.

2009-01-01

We present a quartz crystal microbalance-based system for high sensitivity differential sputter yield measurements of different target materials due to ion bombardment. The differential sputter yields can be integrated to find total yields. Possible ion beam conditions include ion energies in the range of 30-350 eV and incidence angles of 0 deg. - 70 deg. from normal. A four-grid ion optics system is used to achieve a collimated ion beam at low energy (<100 eV) and a two-grid ion optics is used for higher energies (up to 750 eV). A complementary weight loss approach is also used to measure total sputter yields. Validation experiments are presented that confirm high sensitivity and accuracy of sputter yield measurements.

Quantitative Rheometry of Thin Soft Materials Using the Quartz Crystal Microbalance with Dissipation.

Science.gov (United States)

Sadman, Kazi; Wiener, Clinton G; Weiss, R A; White, Christopher C; Shull, Kenneth R; Vogt, Bryan D

2018-03-20

In the inertial limit, the resonance frequency of the quartz crystal microbalance (QCM) is related to the coupled mass on the quartz sensor through the Sauerbrey expression that relates the mass to the change in resonance frequency. However, when the thickness of the film is sufficiently large, the relationship becomes more complicated and both the frequency and damping of the crystal resonance must be considered. In this regime, a rheological model of the material must be used to accurately extract the adhered film's thickness, shear modulus, and viscoelastic phase angle from the data. In the present work we examine the suitability of two viscoelastic models, a simple Voigt model ( Physica Scripta 1999, 59, 391-396) and a more realistic power-law model ( Langmuir 2015, 31, 4008-4017), to extract the rheological properties of a thermoresponsive hydrogel film. By changing temperature and initial dry film thickness of the gel, the operation of QCM was traversed from the Sauerbrey limit, where viscous losses do not impact the frequency, through the regime where the QCM response is sensitive to viscoelastic properties. The density-shear modulus and the viscoelastic phase angle from the two models are in good agreement when the shear wavelength ratio, d/λ n , is in the range of 0.05-0.20, where d is the film thickness and λ n is the wavelength of the mechanical shear wave at the n th harmonic. We further provide a framework for estimating the physical properties of soft materials in the megahertz regime by using the physical behavior of polyelectrolyte complexes. This provides the user with an approximate range of allowable film thicknesses for accurate viscoelastic analysis with either model, thus enabling better use of the QCM-D in soft materials research.

Epoxy Resin Modified Quartz Crystal Microbalance Sensor for Chemical Warfare Agent Sulfur Mustard Vapor Detection

Directory of Open Access Journals (Sweden)

Rajendra BUNKAR

2010-02-01

Full Text Available An epoxy resin polymer coated quartz crystal microbalance (PC-QCM is used for detection of sulfur mustard vapor (SM. When SM vapor is exposed to PC-QCM sensor frequency shift is observed. The response of the sensor in ambient condition is 554 Hz with ±10 % variation upon exposure of 155 ppm of the SM concentration. The observed response loss is nearly 40 % over the period of 15 months. The response of the sensor is higher for SM than compare to structurally similar chloroethyl ether (CEE and other interferences.

Dew Point Calibration System Using a Quartz Crystal Sensor with a Differential Frequency Method.

Science.gov (United States)

Lin, Ningning; Meng, Xiaofeng; Nie, Jing

2016-11-18

In this paper, the influence of temperature on quartz crystal microbalance (QCM) sensor response during dew point calibration is investigated. The aim is to present a compensation method to eliminate temperature impact on frequency acquisition. A new sensitive structure is proposed with double QCMs. One is kept in contact with the environment, whereas the other is not exposed to the atmosphere. There is a thermal conductivity silicone pad between each crystal and a refrigeration device to keep a uniform temperature condition. A differential frequency method is described in detail and is applied to calibrate the frequency characteristics of QCM at the dew point of -3.75 °C. It is worth noting that frequency changes of two QCMs were approximately opposite when temperature conditions were changed simultaneously. The results from continuous experiments show that the frequencies of two QCMs as the dew point moment was reached have strong consistency and high repeatability, leading to the conclusion that the sensitive structure can calibrate dew points with high reliability.

Molecular Imprinting Technology in Quartz Crystal Microbalance (QCM) Sensors

Science.gov (United States)

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

2017-01-01

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. PMID:28245588

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.

Separate density and viscosity measurements of unknown liquid using quartz crystal microbalance

Directory of Open Access Journals (Sweden)

Feng Tan

2016-09-01

Full Text Available Aqueous liquids have a wide range of applications in many fields. Basic physical properties like the density and the viscosity have great impacts on the functionalities of a given ionic liquid. For the millions kinds of existing liquids, only a few have been systematically measured with the density and the viscosity using traditional methods. However, these methods are limited to measure the density and the viscosity of an ionic liquid simultaneously especially in processing micro sample volumes. To meet this challenge, we present a new theoretical model and a novel method to separate density and viscosity measurements with single quartz crystal microbalance (QCM in this work. The agreement of experimental results and theocratical calculations shows that the QCM is capable to measure the density and the viscosity of ionic liquids.

Studies of jet fuel additives using the quartz crystal microbalance and pressure monitoring at 140 C

Energy Technology Data Exchange (ETDEWEB)

Zabarnick, S.; Grinstead, R.R. [Univ. of Dayton Research Institute, OH (United States)

1995-05-01

The quartz crystal microbalance (QCM) and pressure monitoring are used for the evaluation of jet fuel additives for the improvement of jet fuel thermal stability. The mechanisms of additive behavior are determined by measuring the time dependent deposition with the QCM and oxidation by pressure measurements. Studies at various additive concentrations permits the determination of optimum additive concentrations. Additive packages made of mixtures of antioxidants, detergent/dispersants, and metal deactivators are shown to yield good improvements in thermal stability over a wide range of jet fuel types.

Crystal size effect on the electrochemical oxidation of formate on carbon-supported palladium nanoparticles

International Nuclear Information System (INIS)

Santos, Rayana Marcela Izidoro da Silva; Nakazato, Roberto Zenhei; Ciapina, Eduardo Goncalves

2016-01-01

Full text: The electrochemical oxidation of formate in alkaline electrolytes has emerged an a promising anodic reaction in the Direct Formate Fuel Cells[1]. Although palladium is considered to be one of the best electro catalyst for the oxidation of formate, important structure-activity relationships are still not understood. In the present work, we investigated the effect of the size of the palladium crystals in the electrochemical oxidation of formate in 0.1 mol L -1 KOH. Carbon-supported palladium nanoparticles (Pd/C) were prepared by chemical reduction of palladium (II) chloride in aqueous media by sodium borohydride in the presence of varying quantities of sodium citrate in the reaction media to obtain metallic crystals with distinct sizes. Analysis of the X-ray diffraction profile revealed the presence of palladium crystals in the range of 6 to 19 nm. Potentiostatic oxidation of formate on the distinct Pd/C samples revealed a volcano-like dependence of the specific activity with the size of the palladium crystals, presenting the highest activity for crystals around 7.5 nm. Reference: [1] A.M. Bartrom, J.L. Haan, The direct formate fuel cell with an alkaline anion exchange membrane, J. Power Sources. 214 (2012) 68-74. (author)

Measurement of deposition rate and ion energy distribution in a pulsed dc magnetron sputtering system using a retarding field analyzer with embedded quartz crystal microbalance.

Science.gov (United States)

Sharma, Shailesh; Gahan, David; Scullin, Paul; Doyle, James; Lennon, Jj; Vijayaraghavan, Rajani K; Daniels, Stephen; Hopkins, M B

2016-04-01

A compact retarding field analyzer with embedded quartz crystal microbalance has been developed to measure deposition rate, ionized flux fraction, and ion energy distribution arriving at the substrate location. The sensor can be placed on grounded, electrically floating, or radio frequency (rf) biased electrodes. A calibration method is presented to compensate for temperature effects in the quartz crystal. The metal deposition rate, metal ionization fraction, and energy distribution of the ions arriving at the substrate location are investigated in an asymmetric bipolar pulsed dc magnetron sputtering reactor under grounded, floating, and rf biased conditions. The diagnostic presented in this research work does not suffer from complications caused by water cooling arrangements to maintain constant temperature and is an attractive technique for characterizing a thin film deposition system.

Measurement of deposition rate and ion energy distribution in a pulsed dc magnetron sputtering system using a retarding field analyzer with embedded quartz crystal microbalance

Energy Technology Data Exchange (ETDEWEB)

Sharma, Shailesh, E-mail: shailesh.sharma6@mail.dcu.ie [Dublin City University, Glasnevin, Dublin 9 (Ireland); Impedans Limited, Chase House, City Junction Business Park, Northern Cross, D17 AK63, Dublin 17 (Ireland); Gahan, David, E-mail: david.gahan@impedans.com; Scullin, Paul; Doyle, James; Lennon, Jj; Hopkins, M. B. [Impedans Limited, Chase House, City Junction Business Park, Northern Cross, D17 AK63, Dublin 17 (Ireland); Vijayaraghavan, Rajani K.; Daniels, Stephen [Dublin City University, Glasnevin, Dublin 9 (Ireland)

2016-04-15

A compact retarding field analyzer with embedded quartz crystal microbalance has been developed to measure deposition rate, ionized flux fraction, and ion energy distribution arriving at the substrate location. The sensor can be placed on grounded, electrically floating, or radio frequency (rf) biased electrodes. A calibration method is presented to compensate for temperature effects in the quartz crystal. The metal deposition rate, metal ionization fraction, and energy distribution of the ions arriving at the substrate location are investigated in an asymmetric bipolar pulsed dc magnetron sputtering reactor under grounded, floating, and rf biased conditions. The diagnostic presented in this research work does not suffer from complications caused by water cooling arrangements to maintain constant temperature and is an attractive technique for characterizing a thin film deposition system.

Investigating calcite growth rates using a quartz crystal microbalance with dissipation (QCM-D)

Science.gov (United States)

Cao, Bo; Stack, Andrew G.; Steefel, Carl I.; DePaolo, Donald J.; Lammers, Laura N.; Hu, Yandi

2018-02-01

Calcite precipitation plays a significant role in processes such as geological carbon sequestration and toxic metal sequestration and, yet, the rates and mechanisms of calcite growth under close to equilibrium conditions are far from well understood. In this study, a quartz crystal microbalance with dissipation (QCM-D) was used for the first time to measure macroscopic calcite growth rates. Calcite seed crystals were first nucleated and grown on sensors, then growth rates of calcite seed crystals were measured in real-time under close to equilibrium conditions (saturation index, SI = log ({Ca2+}/{CO32-}/Ksp) = 0.01-0.7, where {i} represent ion activities and Ksp = 10-8.48 is the calcite thermodynamic solubility constant). At the end of the experiments, total masses of calcite crystals on sensors measured by QCM-D and inductively coupled plasma mass spectrometry (ICP-MS) were consistent, validating the QCM-D measurements. Calcite growth rates measured by QCM-D were compared with reported macroscopic growth rates measured with auto-titration, ICP-MS, and microbalance. Calcite growth rates measured by QCM-D were also compared with microscopic growth rates measured by atomic force microscopy (AFM) and with rates predicted by two process-based crystal growth models. The discrepancies in growth rates among AFM measurements and model predictions appear to mainly arise from differences in step densities, and the step velocities were consistent among the AFM measurements as well as with both model predictions. Using the predicted steady-state step velocity and the measured step densities, both models predict well the growth rates measured using QCM-D and AFM. This study provides valuable insights into the effects of reactive site densities on calcite growth rate, which may help design future growth models to predict transient-state step densities.

Note: A dual-channel sensor for dew point measurement based on quartz crystal microbalance

Science.gov (United States)

Li, Ning; Meng, Xiaofeng; Nie, Jing

2017-05-01

A new sensor with dual-channel was designed for eliminating the temperature effect on the frequency measurement of the quartz crystal microbalance (QCM) in dew point detection. The sensor uses active temperature control, produces condensation on the surface of QCM, and then detects the dew point. Both the single-channel and the dual-channel methods were conducted based on the device. The measurement error of the single-channel method was less than 0.5 °C at the dew point range of -2 °C-10 °C while the dual-channel was 0.3 °C. The results showed that the dual-channel method was able to eliminate the temperature effect and yield better measurement accuracy.

Frequency shift of a crystal quartz resonator in thickness-shear modes induced by an array of hemispherical material units.

Science.gov (United States)

Yuantai Hu; Huiliang Hu; Bin Luo; Huan Xue; Jiemin Xie; Ji Wang

2013-08-01

A two-dimensional model was established to study the dynamic characteristics of a quartz crystal resonator with the upper surface covered by an array of hemispherical material units. A frequency-dependent equivalent mass ratio was proposed to simulate the effect of the covered units on frequency shift of the resonator system. It was found that the equivalent mass ratio alternately becomes positive or negative with change of shear modulus and radius of each material unit, which indicates that the equivalent mass ratio is strongly related to the vibration mode of the covered loadings. The further numerical results show the cyclical feature in the relationship of frequency shift and shear modulus/radius as expected. The solutions are useful in the analysis of frequency stability of quartz resonators and acoustic wave sensors.

ZnO crystal growth on microelectrode by electrochemical deposition method

International Nuclear Information System (INIS)

Kondo, Y; Ashida, A; Nouzu, N; Fujimura, N

2011-01-01

Zinc Oxide crystals were grown by constant potential electrochemical deposition method on the substrate with the Pt working electrode which consists of Pt film with large area and μm-sized line and space structured area. In case of depositions with cathodic potential of -0.3V, ZnO crystal is not observed on the micro electrode, but observed on the electrode with large area (0.2 cm 2 ). By using electrolyte with higher pH, ZnO crystal grows on both areas. In case of lower pH, ZnO crystal does not grow on either. From these results, the pH range for growth of ZnO on the microelectrode seems to be higher than that on the electrode with large area. And, it is expected that the pH just on the surface of μm-sized electrode is lower than that in the bulk of electrolyte. Based on these results, it can be concluded that control of the pH in vicinity of the surface is very important to ECD method for micro- and nano-scaled devices.

Dew Point Calibration System Using a Quartz Crystal Sensor with a Differential Frequency Method

Directory of Open Access Journals (Sweden)

Ningning Lin

2016-11-01

Full Text Available In this paper, the influence of temperature on quartz crystal microbalance (QCM sensor response during dew point calibration is investigated. The aim is to present a compensation method to eliminate temperature impact on frequency acquisition. A new sensitive structure is proposed with double QCMs. One is kept in contact with the environment, whereas the other is not exposed to the atmosphere. There is a thermal conductivity silicone pad between each crystal and a refrigeration device to keep a uniform temperature condition. A differential frequency method is described in detail and is applied to calibrate the frequency characteristics of QCM at the dew point of −3.75 °C. It is worth noting that frequency changes of two QCMs were approximately opposite when temperature conditions were changed simultaneously. The results from continuous experiments show that the frequencies of two QCMs as the dew point moment was reached have strong consistency and high repeatability, leading to the conclusion that the sensitive structure can calibrate dew points with high reliability.

Improved electronic interfaces for AT-cut quartz crystal microbalance sensors under variable damping and parallel capacitance conditions.

Science.gov (United States)

Arnau, A; García, J V; Jimenez, Y; Ferrari, V; Ferrari, M

2008-07-01

A new configuration of automatic capacitance compensation (ACC) technique based on an oscillatorlike working interface, which permits the tracking of the series resonant frequency and the monitoring of the motional resistance and the parallel capacitance of a thickness-shear mode quartz crystal microbalance sensor, is introduced. The new configuration permits an easier calibration of the system which, in principle, improves the accuracy. Experimental results are reported with 9 and 10 MHz crystals in liquids with different parallel capacitances which demonstrate the effectiveness of the capacitance compensation. Some frequency deviations from the exact series resonant frequency, measured by an impedance analyzer, are explained by the specific nonideal behavior of the circuit components. A tentative approach is proposed to solve this problem that is also common to previous ACC systems.

Improved electronic interfaces for AT-cut quartz crystal microbalance sensors under variable damping and parallel capacitance conditions

International Nuclear Information System (INIS)

Arnau, A.; Garcia, J. V.; Jimenez, Y.; Ferrari, V.; Ferrari, M.

2008-01-01

A new configuration of automatic capacitance compensation (ACC) technique based on an oscillatorlike working interface, which permits the tracking of the series resonant frequency and the monitoring of the motional resistance and the parallel capacitance of a thickness-shear mode quartz crystal microbalance sensor, is introduced. The new configuration permits an easier calibration of the system which, in principle, improves the accuracy. Experimental results are reported with 9 and 10 MHz crystals in liquids with different parallel capacitances which demonstrate the effectiveness of the capacitance compensation. Some frequency deviations from the exact series resonant frequency, measured by an impedance analyzer, are explained by the specific nonideal behavior of the circuit components. A tentative approach is proposed to solve this problem that is also common to previous ACC systems

Quartz Crystal Microbalance with Dissipation (QCM-D) studies of the viscoelastic response from a continuously growing grafted polyelectrolyte layer

DEFF Research Database (Denmark)

Dunér, Gunnar; Thormann, Esben; Dedinaite, Andra

2013-01-01

Poly(acrylic acid) was grown from substrates by photopolymerization, and the grafting process was monitored in situ by Quartz Crystal Microbalance with Dissipation (QCM-D) measurements in a 1:1 v/v mixture of water/ethanol. The polymerization process was monitored into the thick film region, wher...... that should be considered when investigating small changes in thick films used in e.g. sensor applications. © 2013 Elsevier Inc....

Electrochemically Controlled Ion-exchange Property of Carbon Nanotubes/Polypyrrole Nanocomposite in Various Electrolyte Solutions

Energy Technology Data Exchange (ETDEWEB)

Choi, Daiwon [Pacific Northwest National Laboratory, 902 Battelle Boulevard P.O. Box 999 Richland WA 99352 USA; Zhu, Chengzhou [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920 United States; Fu, Shaofang [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920 United States; Du, Dan [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920 United States; Engelhard, Mark H. [Pacific Northwest National Laboratory, 902 Battelle Boulevard P.O. Box 999 Richland WA 99352 USA; Lin, Yuehe [Pacific Northwest National Laboratory, 902 Battelle Boulevard P.O. Box 999 Richland WA 99352 USA; School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920 United States

2016-09-15

The electrochemically controlled ion-exchange properties of multi-wall carbon nanotube (MWNT)/electronically conductive polypyrrole (PPy) polymer composite in the various electrolyte solutions have been investigated. The ion-exchange behavior, rate and capacity of the electrochemically deposited polypyrrole with and without carbon nanotube (CNT) were compared and characterized using cyclic voltammetry (CV), chronoamperometry (CA), electrochemical quartz crystal microbalance (EQCM), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It has been found that the presence of carbon nanotube backbone resulted in improvement in ion-exchange rate, stability of polypyrrole, and higher anion loading capacity per PPy due to higher surface area, electronic conductivity, porous structure of thin film, and thinner film thickness providing shorter diffusion path. Chronoamperometric studies show that electrically switched anion exchange could be completed more than 10 times faster than pure PPy thin film. The anion selectivity of CNT/PPy film is demonstrated using X-ray photoelectron spectroscopy (XPS).

A sensitive molecularly imprinted polymer based quartz crystal microbalance nanosensor for selective determination of lovastatin in red yeast rice.

Science.gov (United States)

Eren, Tanju; Atar, Necip; Yola, Mehmet Lütfi; Karimi-Maleh, Hassan

2015-10-15

Lovastatin (LOV) is a statin, used to lower cholesterol which has been found as a hypolipidemic agent in commercial red yeast rice. In present study, a sensitive molecular imprinted quartz crystal microbalance (QCM) sensor was prepared by fabricating a self-assembling monolayer formation of allylmercaptane on QCM chip surface for selective determination of lovastatin (LOV) in red yeast rice. To prepare molecular imprinted quartz crystal microbalance (QCM) nanosensor, LOV imprinted poly(2-hydroxyethyl methacrylate-methacryloylamidoaspartic acid) [p(HEMA-MAAsp)] nanofilm was attached on the modified gold surface of QCM chip. The non-modified and improved surfaces were characterized by using contact angle, atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy. The imprinted QCM sensor was validated according to the ICH guideline (International Conference on Harmonisation). The linearity range was obtained as 0.10-1.25 nM. The detection limit of the prepared material was calculated as 0.030 nM. The developed QCM nanosensor was successfully used to examine red yeast rice. Furthermore, the stability and repeatability of the prepared QCM nanosensor were studied. The spectacular long-term stability and repeatability of the prepared LOV-imprinted QCM nanosensor make them intriguing for use in QCM sensors. Copyright © 2015 Elsevier Ltd. All rights reserved.

Study of the α and β phases of quartz by neutron multiple diffraction

International Nuclear Information System (INIS)

Mazzocchi, V.L.

1984-01-01

Crystal structures of α and β phases of quartz are studied, employing neutron multiple diffraction as a method of analysis. Theoretical multiple diffraction patterns in a many-beam case were determined by a computer program which calculates intensities of beams as sums of Taylor's series expansions, retaining terms up to a order n. Experimental 'umweg' and transmitted beam patterns were obtained for the 00.1 primary reflection of α and β phases of quartz. To calculate α - quartz multiple diffraction intensities it was necessary to determine the Dauphine twinning fraction for the crystal after having passed by the β-phase. For the two models of β-quartz a better agreement between experimental and calculated integrated intensities was found for the disordered structure model based on split-half-oxigen positions. (Author) [pt

Gold clusters sliding on graphite: a possible quartz crystal microbalance experiment?

International Nuclear Information System (INIS)

Pisov, S; Tosatti, E; Tartaglino, U; Vanossi, A

2007-01-01

A large measured two-dimensional (2D) diffusion coefficient of gold nanoclusters on graphite has been known experimentally and theoretically for about a decade. When subjected to a lateral force, these clusters should slide with an amount of friction that can be measured. We examine the hypothetical possibility of measuring by quartz crystal microbalance (QCM) the phononic sliding friction of gold clusters in the size range around 250 atoms on a graphite substrate between 300 and 600 K. Assuming the validity of Einstein's relations of ordinary Brownian motion and making use of the experimentally available activated behaviour of the diffusion coefficients, we can predict the sliding friction and slip times as a function of temperature. It is found that a prototypical deposited gold cluster could yield slip times at the standard measurable size of 10 -9 s for temperatures around 450-500 K, or 200 0 C. Since gold nanoclusters may also melt at around these temperatures, QCM could offer the additional chance of observing this phenomenon through a frictional change

New Transparent Laser-Drilled Fluorine-doped Tin Oxide covered Quartz Electrodes for Photo-Electrochemical Water Splitting

International Nuclear Information System (INIS)

Hernández, Simelys; Tortello, Mauro; Sacco, Adriano; Quaglio, Marzia; Meyer, Toby; Bianco, Stefano; Saracco, Guido; Pirri, C. Fabrizio; Tresso, Elena

2014-01-01

Graphical abstract: - Highlights: • A new transparent, conductive and porous electrode was developed. • It has a high effective surface area available for catalyst molecules attachment. • It is an ideal support for testing new anodic and cathodic photoactive materials. • The proof-of-concept was achieved in an appositely designed water photo-electrolyzer. • The EIS technique was used as a very powerful tool to characterize the new designed electrode. - Abstract: A new-designed transparent, conductive and porous electrode was developed for application in a compact laboratory-scale proton exchange membrane (PEM) photo-electrolyzer. The electrode is made of a thin transparent quartz sheet covered with fluorine-doped tin oxide (FTO), in which an array of holes is laser-drilled to allow water and gas permeation. The electrical, morphological, optical and electrochemical characterization of the drilled electrodes is presented in comparison with a non-drilled one. The drilled electrode exhibits, in the visible region, a good transmittance (average value of 62%), a noticeable reflectance due to the light scattering effect of the hole-drilled internal region, and a higher effective surface area than the non-drilled electrode. The proof-of-concept of the applicability of the drilled electrode was achieved by using it as a support for a traditional photocatalyst (i.e. commercial TiO 2 nanoparticles). The latter, coupled with a polymeric electrolyte membrane (i.e.Nafion 117) and a Pt counter electrode, forms a transparent membrane electrode assembly (MEA), with a good conductivity, wettability and porosity. Electrochemical impedance spectroscopy (EIS) was used as a very powerful tool to gain information on the real active surface of the new drilled electrode and the main electrochemical parameters driving the charge transfer reactions on it. This new electrode architecture is demonstrated to be an ideal support for testing new anodic and cathodic photoactive

Humidity scanning quartz crystal microbalance with dissipation monitoring setup for determination of sorption-desorption isotherms and rheological changes

Energy Technology Data Exchange (ETDEWEB)

Björklund, Sebastian, E-mail: sebastianbjorklund@gmail.com; Kocherbitov, Vitaly [Department of Biomedical Science, Faculty of Health and Society, Malmö University, Malmö (Sweden); Biofilms—Research Center for Biointerfaces, Malmö University, Malmö (Sweden)

2015-05-15

A new method to determine water sorption-desorption isotherms with high resolution in the complete range of water activities (relative humidities) is presented. The method is based on quartz crystal microbalance with dissipation monitoring (QCM-D). The QCM-D is equipped with a humidity module in which the sample film is kept in air with controlled humidity. The experimental setup allows for continuous scanning of the relative humidity from either dry to humid conditions or vice versa. The amount of water sorbed or desorbed from the sample is determined from the resonance frequencies of the coated quartz sensor, via analysis of the overtone dependence. In addition, the method allows for characterization of hydration induced changes of the rheological properties from the dissipation data, which is closely connected to the viscoelasticity of the film. The accuracy of the humidity scanning setup is confirmed in control experiments. Sorption-desorption isotherms of pig gastric mucin and lysozyme, obtained by the new method, show good agreement with previous results. Finally, we show that the deposition technique used to coat the quartz sensor influences the QCM-D data and how this issue can be used to obtain further information on the effect of hydration. In particular, we demonstrate that spin-coating represents an attractive alternative to obtain sorption-desorption isotherms, while drop-coating provides additional information on changes of the rheological properties during hydration.

EPR investigation into the structure of boron-containing quartz glasses

International Nuclear Information System (INIS)

Amosov, A.V.; Bushmarin, D.B.; Prokhorova, T.I.; Yudin, D.M.

1975-01-01

Certain properties of boron-containing quartz glasses and the nature of occurrence of boron in the glass lattice are studied as functions of the method of alloying. The formation of three types of borate structural nodes (BO 4 , BO 3 and BO 4 -BO 3 ) in the lattice of quartz glasses is established. Alloying by boron oxide up to 3% (weight) increases the crystallization stability of quartz glasses, lowers down tsub(g) from 1220 to 950 deg C and does not affect the coefficient of thermal expansion. Low symmetry of borate structural nodes, following from the analysis of EPR spectra, confirms the literature data concerning the low symmetry of glass-forming polyhedrons in a quartz glass

Alcohol vapours sensor based on thin polyaniline salt film and quartz crystal microbalance.

Science.gov (United States)

Ayad, Mohamad M; Torad, Nagy L

2009-06-15

A sensor based on the quartz crystal microbalance (QCM) technique was developed for detection of a number of primary aliphatic alcohols such as ethanol, methanol, 1-propanol, and 2-propanol vapours. Detection was based on a sensitive and a thin film of polyaniline, emeraldine salt (ES), coated the QCM electrode. The frequency shifts (Delta f) of the QCM were increased due to the vapour absorption into the ES film. The values of Delta f were found to be linearly correlated with the concentrations of alcohols vapour in mg L(-1). The changes in frequency are due to the hydrophilic character of the ES and the electrostatic interaction as well as the type of the alcohol. The sensor shows a good reproducibility and reversibility. The diffusion and diffusion coefficient (D) of different alcohols vapour were determined. It was found that the sensor follows Fickian kinetics.

In-situ quartz crystal microgravimetric studies of molecular adsorbates containing thiol and hydroquinone moieties bound to Au(111) surfaces in aqueous electrolytes

Energy Technology Data Exchange (ETDEWEB)

Mo, Y.; Sukenik, C.; Sandifer, M. [Case Western Univ., Cleveland, OH (United States); Barriga, R.J.; Soriaga, M.P.; Scherson, D. [Texas A& M Univ., College Station, TX (United States)

1995-12-01

The microgravimetric properties of monolayers of 2, 5-dihydroxythiophenol, 2,5-dihydroxybenzyl mercaptan, and 2, 5-dihydroxy-4-methylbenzyl mercaptan adsorbed on Au(111) single crystal electrodes were examined by in situ quartz crystal microbalance techniques in aqueous perchloric acid electrolytes. The results obtained are consistent with the reversible loss of an average of about three waters per adsorbed molecule as the layers are oxidized and subsequently reduced. These observations provide evidence for discrete changes in the extent of bound water within the hydroquinone/quinone layer as the oxidation state of the monolayer is changed. 9 refs., 4 figs.

Orientation of quartz nanocrystallites in the silicon lattice

International Nuclear Information System (INIS)

Kalanov, M.U.; Ibragimova, E.M.; Khamraeva, R.N.; Rustamova, V.M.; Ummatov, Kh.D.

2006-01-01

Full text: Basing on the study of medium angle diffuse X-ray scattering from silicon single crystals, it was supposed to be due to rod like oxygen precipitates. It was shown by us later, that depending on the growth conditions, as-grown silicon single crystals contain quartz crystal inclusions at an amount of 0.3 / 0.5 wt. % . Since it has not been done before, the aim of this work was to study the shape and orientation of quartz inclusions relative to a chosen axis of the silicon crystal lattice. We studied p-Si single crystals of one crucible origin with the specific resistance ρ 0 ≅ 1/10 Ohm· cm with different cut surfaces parallel to the crystal planes (100), (110) and (111). All the samples were cut and polished in the bar form with the sizes of 20x12x1.5 mm 3 . The dislocation density was N D ≅ 10 1 /10 3 cm -2 , the concentrations of oxygen and boron were N O ≅ 2/ 4 x10 17 cm -3 and N B ≅ 3· 10 1 5 c m -3 . Structure was analyzed at the set-up DRON-3M ( λ Cu K∝ = 0.1542 nm) at the room temperature in the angle range of angles 2Θ = 10/70 deg. The diffraction spectrum of the sample cut in (111) includes 5 selective reflections and the only diffuse one at 2Θ≅ 20 deg (d/n≅ 0.3136 nm), having a large width 0.1032 rad, which is due to presence of amorphous SiO x precipitate in the surface layer of silicon single crystal. The dominative selective line with d/n≅ 0.3136 nm at 2Θ≅ 28.5 deg belongs to reflection from (111) planes of the silicon lattice and the second less intensive one comes from the same planes with Cu K β radiation. Another selective reflection of a medium intensity at 2Θ≅ 59 deg with d/n≅ 0.1568 nm is its second order (222) and forbidden by the weakening laws. The rest narrow but weak lines with d/n≅ 0.3345 nm at 2Θ≅ 26.6 deg and 0.2468 nm at≅36.6 deg correspond to the diffraction reflections (101) and (110) from the crystal quartz lattice SiO 2 . It means that they are caused by optimally oriented quartz

Gamma irradiation of quartz from Pannier basin, South America

Energy Technology Data Exchange (ETDEWEB)

Enokihara, Cyro T.; Rela, Paulo R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], E-mail: cteiti@ipen.br, E-mail: prela@ipen.br; Guttler, Rainer A.S. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias

2007-07-01

The use of gamma radiation to induce or enhance color centers in gemstones is a widespread technique and applied worldwide on a industrial scale since at least 1970. The presence of defects and defect structures in quartz from a border region of southern Brazil and Uruguay are the reason for the creation of a new color variety of quartz called 'Prasiolite' in the gem trade. This quartz has a pleasant green color produced by gamma irradiation. The procedures of irradiation at IPEN show that the activation of these color producing defects can be monitored by detailed chemical and spectroscopic analysis. For the first time UV-VIS-NIR spectra of this new color variety of quartz are shown. They revealed special features of these quartz crystals coming from basaltic terranes of the Parana Basin. Contrary to most specimen of quartz from other parts of Brazil, they have such a high water and OH content that they resemble more chalcedony or opal, but not highly crystalline quartz specimens. The cause of the color are broken bonds of Si-OH defining the so-called dangling bonds. (author)

Investigations on low temperature thermoluminescence centres in quartz

International Nuclear Information System (INIS)

Bernhardt, H.

1984-01-01

The present paper will help to understand the often investigated process of thermoluminescence of quartz which is of high complexity. A lot of traps exist in quartz crystals which compete with each other with respect to the trapping of charge carriers during the X-ray treatment. That is why a variety of processes takes place after X-irradiation at liquid nitrogen temperature (LNT) of quartz which complicate the phenomenology of low temperature thermoluminescence. This competition in the trapping process leads to the so-called 'sensibilization' or 'desensibilization' effects of thermoluminescence, respectively, which are described in this paper for the first time. This effect means the dependence of the LNT thermoluminescence intensity on a pre-irradiation dose applied at room temperature (RT). The influence of this pre-irradiation is understood assuming the saturation of competitive traps. This favours an enhanced trapping of charge carriers at LNT-(shallow) traps instead of the preferential trapping on the deep traps in the case of X-ray treatment of the as-grown crystal at LNT. To get the afore mentioned model we take into account not only thermoluminescence but also coloration, ir- and vuv-absorption measurements. (author)

Ion Movement in Polypyrrole/Dodecylbenzenesulphonate Films in aqueous and non-aqueous electrolytes

DEFF Research Database (Denmark)

Vidanapathirana, K.; Careem, M.A.; Skaarup, Steen

2002-01-01

The electrochemical characteristics during the redox process of polypyrrole (PPy) films, prepared using dodecylbenzenesulphonate (DBS-) dopant species, have been investigated using a combination of cyclic voltammetry and Electrochemical Quartz Crystal Microbalance (EQCM) measurements. Investigati......The electrochemical characteristics during the redox process of polypyrrole (PPy) films, prepared using dodecylbenzenesulphonate (DBS-) dopant species, have been investigated using a combination of cyclic voltammetry and Electrochemical Quartz Crystal Microbalance (EQCM) measurements....... Investigations were carried out using aqueous and non-aqueous electrolytes to study the effect of solvent on the ion movement during redox processes. When PPy films are cycled in aqueous electrolytes transport of both anion and cation occurs during oxidation and reduction. However, when cycled in the nonaqueous...

The use of quartz crystal microbalance with dissipation (QCM-D for studying nanoparticle-induced platelet aggregation

Directory of Open Access Journals (Sweden)

Santos-Martinez MJ

2012-01-01

Full Text Available Maria Jose Santos-Martinez1–3, Iwona Inkielewicz-Stepniak1,4, Carlos Medina1, Kamil Rahme5,6, Deirdre M D'Arcy1, Daniel Fox3, Justin D Holmes3,5, Hongzhou Zhang3, Marek Witold Radomski3,51School of Pharmacy and Pharmaceutical Sciences, 2School of Medicine, 3Center for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin, Ireland; 4Department of Medicinal Chemistry, Medical University of Gdansk, Gdansk, Poland; 5Materials and Supercritical Fluids Group, Department of Chemistry and the Tyndall National Institute, University College Cork, Cork, Ireland; 6Department of Sciences, Faculty of Natural and Applied Science, Notre Dame University, Zouk Mosbeh, LebanonAbstract: Interactions between blood platelets and nanoparticles have both pharmacological and toxicological significance and may lead to platelet activation and aggregation. Platelet aggregation is usually studied using light aggregometer that neither mimics the conditions found in human microvasculature nor detects microaggregates. A new method for the measurement of platelet microaggregation under flow conditions using a commercially available quartz crystal microbalance with dissipation (QCM-D has recently been developed. The aim of the current study was to investigate if QCM-D could be used for the measurement of nanoparticle-platelet interactions. Silica, polystyrene, and gold nanoparticles were tested. The interactions were also studied using light aggregometry and flow cytometry, which measured surface abundance of platelet receptors. Platelet activation was imaged using phase contrast and scanning helium ion microscopy. QCM-D was able to measure nanoparticle-induced platelet microaggregation for all nanoparticles tested at concentrations that were undetectable by light aggregometry and flow cytometry. Microaggregates were measured by changes in frequency and dissipation, and the presence of platelets on the sensor surface was confirmed and imaged by

Complex impedance spectroscopy of alkali impurities in as-grown, irradiated and annealed quartz

International Nuclear Information System (INIS)

Devautour-Vinot, S.; Cambon, O.; Prud'homme, N.; Giuntini, J. C.; Boy, J.-J.; Cibiel, G.

2007-01-01

This work compares the dielectric relaxation properties of different crystalline quartz materials, according to their source (natural or synthetics). It is shown that these relaxation properties are due to a hopping process of alkaline (Li + , Na + , and K + ) impurities located near [Al-O 4 ] 5- tetrahedra. A detailed analysis, in terms of the distribution function of the dielectric loss peak, allowed us to perfectly distinguish the different types of as-grown quartz. We show that (i) the natural quartz has less stable M + charge carriers than the synthetic materials and that (ii) the homogeneity of the M + trapping sites, created by the [Al-O 4 ] 5- tetrahedra, strongly depends on the crystal growth conditions. These features were then studied using quartz samples with different treatment conditions: as-grown, irradiated, or annealed at high temperature. We propose that the irradiation greatly facilitates the M + relaxation, by creating additional low energy M + hosting sites, whose number depends on the source of the quartz crystals. We also show that for 100 krad irradiation, the saturation state of the defects is already reached for all the materials under consideration. Finally, we propose that the irradiation followed by annealing at 450 deg. C improves the M + stability and homogeneity in quartz materials, compared with the as-grown materials, this trend being much more relevant for the natural than for the synthetic quartz

Radiation-Induced Changes in Quartz, A Mineral Analog of Nuclear Power Plant Concrete Aggregates.

Science.gov (United States)

Silva, Chinthaka M; Rosseel, Thomas M; Kirkegaard, Marie C

2018-03-19

Quartz single-crystal samples consisting of α-quartz crystal structure were neutron irradiated to fluences of 5 × 10 18 , 4 × 10 19 , and 2 × 10 20 n/cm 2 (E > 0.1 MeV) at two temperatures (52 and 95 °C). The changes in the α-quartz phase as a function of these two conditions (temperature and fluence) were studied using X-ray powder diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM), and the results acquired using these complementary techniques are presented in a single place for the first time. XRD studies showed that the lattice parameters of α-quartz increased with increasing neutron flux. The lattice growth was larger for the samples that were neutron irradiated at 52 °C than at 95 °C. Moreover, an amorphous content was determined in the quartz samples neutron irradiated at 4 × 10 19 n/cm 2 , with the greater amount being in the 52 °C irradiated sample. Complete amorphization of quartz was observed at a fluence of 2 × 10 20 n/cm 2 (E > 0.1 MeV) using XRD and confirmed by TEM characterization and Raman spectroscopic studies. The cause for α-quartz lattice expansion and sample amorphization was also explored using XRD and Raman spectroscopic studies.

An all-solid-state electrochemical double-layer capacitor based on a plastic crystal electrolyte

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Ali eaabouimrane

2015-08-01

Full Text Available A plastic crystal, solid electrolyte was prepared by mixing tetrabutylammonium hexafluorophosphate salt, (C4H94NPF6, (10 molar % with succinonitrile, SCN, (N C−CH2−CH2−C N, [SCN-10%TBA-PF6]. The resultant waxy material shows a plastic crystalline phase that extend from -36 °C up to its melting at 23 °C. It shows a high ionic conductivity reaching 4 × 10−5 S/cm in the plastic crystal phase (15 °C and ~ 3 × 10−3 S/cm in the molten state (25 °C. These properties along with the high electrochemical stability rendered the use of this material as an electrolyte in an electrochemical double-layer capacitor (EDLC. The EDLC was assembled and its performance was tested by cyclic voltammetry, AC impedance spectroscopy and galvanostatic charge-discharge methods. Specific capacitance values in the range of 4-7 F/g. (of electrode active material were obtained in the plastic crystal phase at 15 °C, that although compare well with those reported for some polymer electrolytes, can be still enhanced with further development of the device and its components, and only demonstrate their great potential use for capacitors as a new application.

An All-Solid-State Electrochemical Double-Layer Capacitor Based on a Plastic Crystal Electrolyte

Energy Technology Data Exchange (ETDEWEB)

Abouimrane, Ali; Belharouak, Ilias [Qatar Environment and Energy Research Institute, Qatar Foundation, Doha (Qatar); Abu-Lebdeh, Yaser A., E-mail: yaser.abu-lebdeh@nrc.gc.ca [Energy, Mining and Environment Portfolio and Automotive and Surface Transportation Portfolio, National Research Council of Canada, Ottawa, ON (Canada)

2015-08-18

A plastic crystal, solid electrolyte was prepared by mixing tetrabutylammonium hexafluorophosphate salt, (C{sub 4}H{sub 9}){sub 4}-NPF{sub 6}, (10 molar %) with succinonitrile, SCN, (N≡C−CH{sub 2}−CH{sub 2}−C≡N), [SCN-10%TBA-PF{sub 6}]. The resultant waxy material shows a plastic crystalline phase that extends from −36°C up to its melting at 23°C. It shows a high ionic conductivity reaching 4 × 10{sup -5} S/cm in the plastic crystal phase (15°C) and ~ 3 × 10{sup -3} S/cm in the molten state (25°C). These properties along with the high electrochemical stability rendered the use of this material as an electrolyte in an electrochemical double-layer capacitor (EDLC). The EDLC was assembled, and its performance was tested by cyclic voltammetry, AC impedance spectroscopy, and galvanostatic charge–discharge methods. Specific capacitance values in the range of 4–7 F/g (of electrode active material) were obtained in the plastic crystal phase at 15°C, that although compare well with those reported for some polymer electrolytes, can be still enhanced with further development of the device and its components, and only demonstrate their great potential use for capacitors as a new application.

An All-Solid-State Electrochemical Double-Layer Capacitor Based on a Plastic Crystal Electrolyte

International Nuclear Information System (INIS)

Abouimrane, Ali; Belharouak, Ilias; Abu-Lebdeh, Yaser A.

2015-01-01

A plastic crystal, solid electrolyte was prepared by mixing tetrabutylammonium hexafluorophosphate salt, (C 4 H 9 ) 4 -NPF 6 , (10 molar %) with succinonitrile, SCN, (N≡C−CH 2 −CH 2 −C≡N), [SCN-10%TBA-PF 6 ]. The resultant waxy material shows a plastic crystalline phase that extends from −36°C up to its melting at 23°C. It shows a high ionic conductivity reaching 4 × 10 -5 S/cm in the plastic crystal phase (15°C) and ~ 3 × 10 -3 S/cm in the molten state (25°C). These properties along with the high electrochemical stability rendered the use of this material as an electrolyte in an electrochemical double-layer capacitor (EDLC). The EDLC was assembled, and its performance was tested by cyclic voltammetry, AC impedance spectroscopy, and galvanostatic charge–discharge methods. Specific capacitance values in the range of 4–7 F/g (of electrode active material) were obtained in the plastic crystal phase at 15°C, that although compare well with those reported for some polymer electrolytes, can be still enhanced with further development of the device and its components, and only demonstrate their great potential use for capacitors as a new application.

Quartz crystal microbalance (QCM) affinity biosensor for genetically modified organisms (GMOs) detection.

Science.gov (United States)

Mannelli, Ilaria; Minunni, Maria; Tombelli, Sara; Mascini, Marco

2003-03-01

A DNA piezoelectric sensor has been developed for the detection of genetically modified organisms (GMOs). Single stranded DNA (ssDNA) probes were immobilised on the sensor surface of a quartz crystal microbalance (QCM) device and the hybridisation between the immobilised probe and the target complementary sequence in solution was monitored. The probe sequences were internal to the sequence of the 35S promoter (P) and Nos terminator (T), which are inserted sequences in the genome of GMOs regulating the transgene expression. Two different probe immobilisation procedures were applied: (a) a thiol-dextran procedure and (b) a thiol-derivatised probe and blocking thiol procedure. The system has been optimised using synthetic oligonucleotides, which were then applied to samples of plasmidic and genomic DNA isolated from the pBI121 plasmid, certified reference materials (CRM), and real samples amplified by the polymerase chain reaction (PCR). The analytical parameters of the sensor have been investigated (sensitivity, reproducibility, lifetime etc.). The results obtained showed that both immobilisation procedures enabled sensitive and specific detection of GMOs, providing a useful tool for screening analysis in food samples.

A hybrid humidity sensor using optical waveguides on a quartz crystal microbalance

International Nuclear Information System (INIS)

Shinbo, Kazunari; Otuki, Shunya; Kanbayashi, Yuichi; Ohdaira, Yasuo; Baba, Akira; Kato, Keizo; Kaneko, Futao; Miyadera, Nobuo

2009-01-01

In this study, slab and ridge optical waveguides (OWGs) made of fluorinated polyimides were deposited on a quartz crystal microbalance (QCM), and hybrid sensors using OWG spectroscopy and the QCM technique were prepared. Polyvinyl alcohol (PVA) film with CoCl 2 was deposited on the OWGs, and the characteristics of humidity sensing were investigated. A prism coupler was used to enter a He-Ne laser beam (λ = 632.8 nm) to the slab OWG. The output light intensity markedly changed due to chromism of the CoCl 2 as a result of humidity sorption, and this change was dependent on the incident angle of the laser beam to the slab OWG. During the measurement of output light, the QCM frequency was simultaneously monitored. The humidity dependence of the sensor with the slab OWG was also investigated in the range from 15 to 85%. For the sensor with the ridge OWG, white light was entered by butt-coupling, and the characteristics of humidity sensing were investigated by observing the output light spectrum and the QCM frequency.

Electrochemical Biosensors - Sensor Principles and Architectures

Science.gov (United States)

Grieshaber, Dorothee; MacKenzie, Robert; Vörös, Janos; Reimhult, Erik

2008-01-01

Quantification of biological or biochemical processes are of utmost importance for medical, biological and biotechnological applications. However, converting the biological information to an easily processed electronic signal is challenging due to the complexity of connecting an electronic device directly to a biological environment. Electrochemical biosensors provide an attractive means to analyze the content of a biological sample due to the direct conversion of a biological event to an electronic signal. Over the past decades several sensing concepts and related devices have been developed. In this review, the most common traditional techniques, such as cyclic voltammetry, chronoamperometry, chronopotentiometry, impedance spectroscopy, and various field-effect transistor based methods are presented along with selected promising novel approaches, such as nanowire or magnetic nanoparticle-based biosensing. Additional measurement techniques, which have been shown useful in combination with electrochemical detection, are also summarized, such as the electrochemical versions of surface plasmon resonance, optical waveguide lightmode spectroscopy, ellipsometry, quartz crystal microbalance, and scanning probe microscopy. The signal transduction and the general performance of electrochemical sensors are often determined by the surface architectures that connect the sensing element to the biological sample at the nanometer scale. The most common surface modification techniques, the various electrochemical transduction mechanisms, and the choice of the recognition receptor molecules all influence the ultimate sensitivity of the sensor. New nanotechnology-based approaches, such as the use of engineered ion-channels in lipid bilayers, the encapsulation of enzymes into vesicles, polymersomes, or polyelectrolyte capsules provide additional possibilities for signal amplification. In particular, this review highlights the importance of the precise control over the delicate

Frequency-shift vs phase-shift characterization of in-liquid quartz crystal microbalance applications

International Nuclear Information System (INIS)

Montagut, Y. J.; Garcia, J. V.; Jimenez, Y.; Arnau, A.; March, C.; Montoya, A.

2011-01-01

The improvement of sensitivity in quartz crystal microbalance (QCM) applications has been addressed in the last decades by increasing the sensor fundamental frequency, following the increment of the frequency/mass sensitivity with the square of frequency predicted by Sauerbrey. However, this sensitivity improvement has not been completely transferred in terms of resolution. The decrease of frequency stability due to the increase of the phase noise, particularly in oscillators, made impossible to reach the expected resolution. A new concept of sensor characterization at constant frequency has been recently proposed. The validation of the new concept is presented in this work. An immunosensor application for the detection of a low molecular weight contaminant, the insecticide carbaryl, has been chosen for the validation. An, in principle, improved version of a balanced-bridge oscillator is validated for its use in liquids, and applied for the frequency shift characterization of the QCM immunosensor application. The classical frequency shift characterization is compared with the new phase-shift characterization concept and system proposed.

Formation of cogenetic quartz and nepheline syenites

Science.gov (United States)

Foland, K. A.; Landoll, J. D.; Henderson, C. M. B.; Chen, Jiangfeng

1993-02-01

Understanding the processes involved in the formation of cogenetic silica-undersaturated and silica-saturated felsic rocks in alkaline igneous complexes has been a long-standing enigma because of constraints imposed by phase equilibria relationships. This problem is discussed in general drawing upon relationships at two magmatic centers: Marangudzi in Zimbabwe and Mt. Brome in Quebec, Canada. At each locality, cogenetic quartz and nepheline syenites appear to be derived from common critically undersaturated magmas. Strontium and neodymium isotope results indicate that quartz syenites bear the signatures of substantial amounts of crustal assimilation whereas nepheline syenites lack or display lesser effects. In the model outlined, quartz syenite melts develop from felsic silica undersaturated magmas by assimilation of granitic crust coupled with fractional crystallization whereas nepheline syenites form without large amounts of contamination. This model is compatible with the constraints imposed by phase equilibria.

Silicon-based photonic crystals fabricated using proton beam writing combined with electrochemical etching method.

Science.gov (United States)

Dang, Zhiya; Breese, Mark Bh; Recio-Sánchez, Gonzalo; Azimi, Sara; Song, Jiao; Liang, Haidong; Banas, Agnieszka; Torres-Costa, Vicente; Martín-Palma, Raúl José

2012-07-23

A method for fabrication of three-dimensional (3D) silicon nanostructures based on selective formation of porous silicon using ion beam irradiation of bulk p-type silicon followed by electrochemical etching is shown. It opens a route towards the fabrication of two-dimensional (2D) and 3D silicon-based photonic crystals with high flexibility and industrial compatibility. In this work, we present the fabrication of 2D photonic lattice and photonic slab structures and propose a process for the fabrication of 3D woodpile photonic crystals based on this approach. Simulated results of photonic band structures for the fabricated 2D photonic crystals show the presence of TE or TM gap in mid-infrared range.

Assessing the adsorption selectivity of linker functionalized, moisture-stable metal-organic framework thin films by means of an environment-controlled quartz crystal microbalance.

Science.gov (United States)

Bétard, Angélique; Wannapaiboon, Suttipong; Fischer, Roland A

2012-11-04

The stepwise thin film deposition of the robust, hydrophobic [Zn(4)O(dmcapz)(3)](n) (dmcapz = 3,5-dimethyl-4-carboxy-pyrazolato) is reported. The adsorption of small organic probe molecules, including alkanols, toluene, aniline and xylenes, was monitored by an environment-controlled quartz crystal microbalance setup. The adsorption selectivity was tuned by introducing alkyl side chains in the dmcapz linker.

A sensor of alcohol vapours based on thin polyaniline base film and quartz crystal microbalance.

Science.gov (United States)

Ayad, Mohamad M; El-Hefnawey, Gad; Torad, Nagy L

2009-08-30

Thin films of polyaniline base, emeraldine base (EB), coating on the quartz crystal microbalance (QCM) electrode were used as a sensitive layer for the detection of a number of primary aliphatic alcohols such as ethanol, methanol, 2-propanol and 1-propanol vapours. The frequency shifts (Deltaf) of the QCM were increased due to the vapour adsorption into the EB film. Deltaf were found to be linearly correlated with the concentrations of alcohols vapour in part per million (ppm). The sensitivity of the sensor was found to be governed by the chemical structure of the alcohol. The sensor shows a good reproducibility and reversibility. The diffusions of different alcohols vapour were studied and the diffusion coefficients (D) were calculated. It is concluded that the diffusion of the vapours into the EB film follows Fickian kinetics.

In-Line Measurement of Water Contents in Ethanol Using a Zeolite-Coated Quartz Crystal Microbalance

Directory of Open Access Journals (Sweden)

Byoung Chul Kim

2015-10-01

Full Text Available A quartz crystal microbalance (QCM was utilized to measure the water content in ethanol. For the improvement of measurement sensitivity, the QCM was modified by applying zeolite particles on the surface with poly(methyl methacrylate (PMMA binder. The measurement performance was examined with ethanol of 1% to 5% water content in circulation. The experimental results showed that the frequency drop of the QCM was related with the water content though there was some deviation. The sensitivity of the zeolite-coated QCM was sufficient to be implemented in water content determination, and a higher ratio of silicon to aluminum in the molecular structure of the zeolite gave better performance. The coated surface was inspected by microscopy to show the distribution of zeolite particles and PMMA spread.

Electrochemical Biosensors - Sensor Principles and Architectures

Directory of Open Access Journals (Sweden)

Erik Reimhult

2008-03-01

Full Text Available Quantification of biological or biochemical processes are of utmost importancefor medical, biological and biotechnological applications. However, converting the biologicalinformation to an easily processed electronic signal is challenging due to the complexity ofconnecting an electronic device directly to a biological environment. Electrochemical biosensorsprovide an attractive means to analyze the content of a biological sample due to thedirect conversion of a biological event to an electronic signal. Over the past decades severalsensing concepts and related devices have been developed. In this review, the most commontraditional techniques, such as cyclic voltammetry, chronoamperometry, chronopotentiometry,impedance spectroscopy, and various field-effect transistor based methods are presented alongwith selected promising novel approaches, such as nanowire or magnetic nanoparticle-basedbiosensing. Additional measurement techniques, which have been shown useful in combinationwith electrochemical detection, are also summarized, such as the electrochemical versionsof surface plasmon resonance, optical waveguide lightmode spectroscopy, ellipsometry,quartz crystal microbalance, and scanning probe microscopy.The signal transduction and the general performance of electrochemical sensors are often determinedby the surface architectures that connect the sensing element to the biological sampleat the nanometer scale. The most common surface modification techniques, the various electrochemicaltransduction mechanisms, and the choice of the recognition receptor moleculesall influence the ultimate sensitivity of the sensor. New nanotechnology-based approaches,such as the use of engineered ion-channels in lipid bilayers, the encapsulation of enzymesinto vesicles, polymersomes, or polyelectrolyte capsules provide additional possibilities forsignal amplification.In particular, this review highlights the importance of the precise control over the

Relationship of Technological Properties with Dynamic Recrystallization of Quartz on the Example of Objects of the Karelian-Kola Region

Science.gov (United States)

Skamnitskaya, Lubov; Rakov, Leonid; Bubnova, Tatyana; Shchiptsov, Vladimir

2017-12-01

Despite the significant reserves of quartz raw materials, there is a deficit of high purity quartz. It is due to the strict technical requirements imposed by standards for this type of raw materials and technological properties of quartz, which are determined by the features of the crystal structure. The crystalline structure is of particular importance for the technological properties of quartz, since such important characteristics as the limit of raw material enrichment, dissolution rate in acid, melting point of quartz, etc., are determined. The formation of the crystal structure of quartz under natural conditions is associated with the successive dynamic recrystallization of the mineral. The degree of dynamic recrystallization of quartz reflects the distribution of dispersed impurities. If it is weakly manifested, the dispersed impurities are not displaced from one zone to another, and all quartz microblocks contain approximately the same concentration. In this case, more or less uniform dissolution of various regions of quartz is observed, and the pattern of distribution of submicroscopic inhomogeneities is monotonic. If intensive dynamic recrystallization of quartz takes place, then it causes a significant redistribution of the scattered impurities. Then the treatment in HF leads to the appearance of a contrast pattern of the distribution of submicroscopic inhomogeneities. The details of the crystal structure of quartz in this work were investigated by the electron paramagnetic resonance (EPR) method using the ER-420 “Bruker” spectrometer. In the selected samples of quartz, the concentrations of isomorphic impurities Al and Ti were measured, and the degree of crystallinity D of the mineral was estimated from the EPR spectra of each of them. Thus, the technological properties of quartz are determined by various geological processes. The results of the studies show that when evaluating the prospects of quartz raw materials, it is necessary to take into

A different point of view on the sensitivity of quartz crystal microbalance sensors

International Nuclear Information System (INIS)

Arnau, Antonio; Montagut, Yeison; García, José V; Jiménez, Yolanda

2009-01-01

In this paper, the sensitivity of a quartz crystal microbalance (QCM) sensor is analysed and discussed in terms of the phase change versus the surface mass change, instead of the classical sensitivity in terms of the resonant frequency change derived from the well-known Sauerbrey equation. The detection sensitivity derived from the Sauerbrey equation is a theoretical detection capability in terms of the frequency change versus the mass change, which increases with the square of frequency. However, when a specific application and measuring system are considered, the detection capability of the QCM sensor must be considered from a different point of view. A new equation is obtained, Δψ ≅ −Δm c /(m q + m L ), which quantifies the phase shift, Δψ, of a fixed frequency signal corresponding to the series resonant frequency of the sensor in a reference state versus a change in the coating mass, Δm c ; m q = η q π/2v q , where η q is the loss viscosity of the unperturbed sensor and v q is the wave propagation speed in quartz, is a parameter which only depends on the physical parameters of the unperturbed resonator and fixes the maximum sensitivity of the sensor and m L = ρ L δ L /2, where ρ L and δ L are, respectively, the liquid density and the wave penetration depth of the wave in the liquid, is the equivalent surface mass density associated with the oscillatory movement of the surface of the sensor in contact with a fluid medium. This equation is an approximate equation around the series resonance frequency of the sensor. The simulation results for 10, 50 and 150 MHz resonance frequency QCM sensors probe its validity. A new electronic system is proposed for QCM biosensor applications based on the equation introduced

Study of green quartz of hydrothermal origin treated by gamma radiation

International Nuclear Information System (INIS)

Enokihara, Cyro Teiti

2013-01-01

A specific variety of quartz showing a green color in nature or induced artificially by radiation is quite rare. This can be explained by the fact that the mechanism of formation of this color is very different from the ones widely discussed in the literature and responsible for the formation of the fumee, citrine and amethyst types of quartz, including the prasiolite (leak green quartz) formed by heating amethyst from Montezuma, Brazil. Only two occurrences are known today, where this type of quartz can be found: Canada, at the Thunder Bay Amethyst Mine, Ontario, a small district, and Brazil, at widely scattered geode occurrences along a 600 km stretch from Quarai at Brazils southernmost tip to Uberlandia in Minas Gerais. These two occurrences have been formed by strong hydrothermal activities, at Thunder Bay due to tectonics and in Brazil by meteoric and hydrothermal waters of the Guarani aquifer. 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. This type of quartz can be considered 'wet quartz', similar to synthetic quartz. 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. Instead, silanol complexes are formed, which by radiation due to gamma rays form the color center NBOHC (non-bonding oxygen hole defect), showing absorption between 590 to 620 nm and leaving a transmission window at about 550nm, responsible for the green color. To characterize samples which will be colored green by gamma rays analyses by ICP, NAA, Electron microscopy, water loss techniques and UV-VIS and NIR-FTIR spectroscopic have been made. The spectroscopic water determination showed less water (up to 2300 ppm by weight) compared with

Synthesis of fully and partially sulfonated polyanilines derived from ortanilic acid: An electrochemical and electromicrogravimetric study

International Nuclear Information System (INIS)

Cano Marquez, Abraham Guadalupe; Torres Rodriguez, Luz Maria; Montes Rojas, Antonio

2007-01-01

The electrochemical polymerization of 2-aminobenzene sulfonic acid, also called ortanilic acid (o-ASA), on a gold electrode precoated with polyaniline (PANI), has been carried out. We proved that the electropolymerization of o-ASA is enhanced on PANI electrodes, resulting in thicker films obtained in aqueous media at room temperature. The electrosynthesized film (P(o-ASA)) was characterized by cyclic voltammetry, FTIR and nuclear magnetic resonance. The compensation of P(o-ASA) charge was evaluated using electrochemical quartz crystal microbalance combined with cyclic voltammetry, which showed that the electroneutralization process mainly involves cations. Additionally, copolymers of aniline and o-ASA were electrosynthesized, using a metallic electrode modified with PANI also as a working electrode. The degree of sulfanation of copolymers has been modulated with the proportions of monomers in the electrosynthesis solution. The studies reveal a more important participation of cations in fully sulfonated polyaniline than in partially sulfonated polyaniline

Synthesis, crystal structure and electrochemical properties of the manganese-doped LiNaFe[PO{sub 4}]F materials

Energy Technology Data Exchange (ETDEWEB)

Ben Yahia, Hamdi, E-mail: benyahia.hamdi@aist.go.jp; Shikano, Masahiro, E-mail: shikano.masahiro@aist.go.jp; Sakaebe, Hikari; Kobayashi, Hironori

2013-08-15

The new compounds LiNaFe{sub 1−x}Mn{sub x}[PO{sub 4}]F (x ≤ 1/4) were synthesized by a solid state reaction route. The crystal structure of LiNaFe{sub 3/4}Mn{sub 1/4}[PO{sub 4}]F was determined from single crystal X-ray diffraction data. LiNaFe{sub 3/4}Mn{sub 1/4}[PO{sub 4}]F crystallizes with the Li{sub 2}Ni[PO{sub 4}]F-type structure, space group Pnma, a = 10.9719(13), b = 6.3528(7), c = 11.4532(13) Å, V = 798.31(16) Å{sup 3}, and Z = 8. The structure consists of edge-sharing (Fe{sub 3/4}Mn{sub 1/4})O{sub 4}F{sub 2} octahedra forming (Fe{sub 3/4}Mn{sub 1/4})FO{sub 3} chains running along the b-axis. These chains are interlinked by PO{sub 4} tetrahedra forming a three-dimensional framework with the tunnels and the cavities filled by the well-ordered sodium and lithium atoms, respectively. The manganese-doped phases show poor electrochemical behavior comparing to the iron pure phase LiNaFe[PO{sub 4}]F. - Highlights: • We investigated the synthesis of LiNaFe{sub 1−x}Mn{sub x}[PO{sub 4}]F by solid state reaction. • We demonstrated that a solid solution exist only for x ≤ 1/4. • We solved the crystal structure of LiNaFe{sub 3/4}Mn{sub 1/4}[PO{sub 4}]F using single crystal data. • We studied the electrochemical performances of LiNaFe{sub 1−x}Mn{sub x}[PO{sub 4}]F. • The Mn-doped phases have poor electrochemical performances comparing to LiNaFe[PO{sub 4}]F.

Characterization of growth sectors in synthetic quartz grown from cylindrical seeds parallel to [0001] direction

Directory of Open Access Journals (Sweden)

Pedro Luiz Guzzo

2004-06-01

Full Text Available In the present study, the morphology and the impurity distribution were investigated in growth sectors formed around the [0001] axis of synthetic quartz crystals. Plates containing cylindrical holes and cylindrical bars parallel to [0001] were prepared by ultrasonic machining and further used as seed-crystals. The hydrothermal growth of synthetic quartz was carried out in a commercial autoclave under NaOH solution during 50 days. The morphologies of crystals grown from cylindrical seeds were characterized by X-ray diffraction topography. For both types of crystals, +X- and X- growth sectors were distinctly observed. Infrared spectroscopy and ionizing radiation were adopted to reveal the distribution of point defects related to Si-Al substitution and OH-species. It was found a different distribution of Al-related centers in relation to the crystals grown from conventional Y-bar and Z-plate seeds.

Fundamental study on dissolution behavior of poly(methyl methacrylate) by quartz crystal microbalance

Science.gov (United States)

Konda, Akihiro; Yamamoto, Hiroki; Yoshitake, Shusuke; Kozawa, Takahiro

2016-03-01

Ionizing radiations such as extreme ultraviolet (EUV) and electron beam (EB) are the most promising exposure source for next-generation lithographic technology. In the realization of high resolution lithography, it is necessary for resist materials to improve the trade-off relationship among sensitivity, resolution, and line width roughness (LWR). In order to overcome them, it is essential to understand basic chemistry of resist matrices in resist processes. In particular, the dissolution process of resist materials is a key process. Therefore, it is essential for next-generation resist design for ionizing radiation to clarify the dissolution behavior of the resist film into developer. However, the details in dissolution process of EUV and EB resist films have not been investigated thus far. In this study, main chain scission and dissolution behavior of poly(methyl methacrylate) (PMMA) as main chain scission type resist was investigated using quartz crystal microbalance (QCM) method and gel permeation chromatography (GPC) in order to understand the relationship between the degree of PMMA degradation and dissolution behavior. The relationship between the molecular weight after irradiation and the swelling behavior was clarified.

Dating quartz: Ar/Ar analyses of coexisting muscovite and fluid inclusion - rich quartz from paleocene amorphic aureole

International Nuclear Information System (INIS)

Matthews, S.J.; Perez de Arce, C.; Cornejo, P.; Cuitino, L; Klein, J

2001-01-01

We present Ar/Ar total fusion and step-heating data for coexisting muscovite and white quartz from the metamorphic aureole of the Lower Paleocene La Copiapina Pluton, 6 km south of Inca de Oro, III Region, Chile. The pluton intrudes the upper clastic sedimentary member of the Punta del Cobre Group (Upper Jurassic - Lower Cretaceous) and the calcareous sedimentary rocks of the Chanarcillo Group (Neocomian), and comprises fine to coarse grained pyroxene-hornblende-biotite quartz diorites and monzodiorites. Its emplacement was controlled on its north-western side by a subvertical NE-trending fault, along which were developed vertically banded skarns (skarn mylonite), suggesting syntectonic intrusion. Biotite K-Ar ages for the pluton fall in the range 61-63 Ma, relating it to a latest Cretaceous to Lowest Paleocene syn-compressional intrusive belt which is present in the area (Matthews and Cornejo, 2000). A metamorphic / metasomatic aureole is developed within the sandstones of the Punta del Cobre Group, on the extreme northern limit of the pluton. In this area, the sedimentary rocks have been replaced by quartz-sericite and quartz-muscovite assemblages, with minor hematite and tourmaline, and late supergene kaolinite and pyrophyllite. A coarse muscovite-quartz-tourmaline-hematite assemblage is developed in and around older (early Upper Cretaceous) andesitic dykes, in the form of replacement / fracture fill veins and replacement zones. Further from the contact with the pluton, fine-grained quartz-sericite rock with coarser muscovite-rich replacement veins represents the dominant lithology. Quartz in the coarse replacement rock is very rich in fluid inclusions. Primary inclusions are mainly of two coexisting types; bi-phase (liquid and gas bubble) and tri-phase (liquid, gas bubble and halite crystal), indicating that the quartz formed in the presence of a boiling fluid. Some inclusions also contain sylvite and occasional hematite daughter crystals. Secondary inclusions

Electrochemical functionalization of Au by aminobenzene and 2-aminotoluene

International Nuclear Information System (INIS)

Rösicke, F; Neubert, T; Rappich, J; Sun, G; Hinrichs, K; Janietz, S

2016-01-01

Au surfaces are functionalized by aminobenzene (AB) and 2-aminotoluene (AT) using the electrochemical reduction of diazotized 1,4-diaminobenzene and 2,5-diaminotoluene. The IR spectroscopic measurements reveal the successful modification of Au surfaces by AB and AT. Both types of layers show similar thicknesses as obtained by microgravimetric measurements via electrochemical quartz crystal microbalance (EQCM). However, the faradaic efficiency for the grafting of AT onto an EQCM-Au sensor was 6% compared to 41% for the grafting of AB. This behavior points to a steric hindrance during the binding of AT to the EQCM surface induced by the additional methyl group present in the toluene derivative. The AB and AT functionalized surfaces have been further modified by the amidation reaction of EDC/NHS activated 4-nitrobenzoic acid. This model system reveals that the amidation reaction is slightly hindered in case of the AT layer due to the presence of the methyl group close to the amino group. This behavior leads to a four times less amount of amide bonds at the AT compared to AB modified Au surfaces as obtained from IR spectroscopic measurements. (paper)

Magma reservoir dynamics at Toba caldera, Indonesia, recorded by oxygen isotope zoning in quartz.

Science.gov (United States)

Budd, David A; Troll, Valentin R; Deegan, Frances M; Jolis, Ester M; Smith, Victoria C; Whitehouse, Martin J; Harris, Chris; Freda, Carmela; Hilton, David R; Halldórsson, Sæmundur A; Bindeman, Ilya N

2017-01-25

Quartz is a common phase in high-silica igneous rocks and is resistant to post-eruptive alteration, thus offering a reliable record of magmatic processes in silicic magma systems. Here we employ the 75 ka Toba super-eruption as a case study to show that quartz can resolve late-stage temporal changes in magmatic δ 18 O values. Overall, Toba quartz crystals exhibit comparatively high δ 18 O values, up to 10.2‰, due to magma residence within, and assimilation of, local granite basement. However, some 40% of the analysed quartz crystals display a decrease in δ 18 O values in outermost growth zones compared to their cores, with values as low as 6.7‰ (maximum ∆ core-rim  = 1.8‰). These lower values are consistent with the limited zircon record available for Toba, and the crystallisation history of Toba quartz traces an influx of a low-δ 18 O component into the magma reservoir just prior to eruption. Here we argue that this late-stage low-δ 18 O component is derived from hydrothermally-altered roof material. Our study demonstrates that quartz isotope stratigraphy can resolve magmatic events that may remain undetected by whole-rock or zircon isotope studies, and that assimilation of altered roof material may represent a viable eruption trigger in large Toba-style magmatic systems.

Effective antibodies immobilization and functionalized nanoparticles in a quartz-crystal microbalance-based immunosensor for the detection of parathion.

Directory of Open Access Journals (Sweden)

Bartolomeo Della Ventura

Full Text Available Biosensor-based detection provides a rapid and low-cost alternative to conventional analytical methods for revealing the presence of the contaminants in water as well as solid matrices. Although important to be detected, small analytes (few hundreds of Daltons are an issue in biosensing since the signal they induce in the transducer, and specifically in a Quartz-Crystal Microbalance, is undetectable. A pesticide like parathion (M = 292 Da is a typical example of contaminant for which a signal amplification procedure is desirable.The ballasting of the analyte by gold nanoparticles has been already applied to heavy target as proteins or bacteria to improve the limit of detection. In this paper, we extend the application of such a method to small analytes by showing that once the working surface of a Quartz-Crystal Microbalance (QCM has been properly functionalized, a limit of detection lower than 1 ppb is reached for parathion. The effective surface functionalization is achieved by immobilizing antibodies upright oriented on the QCM gold surface by a simple photochemical technique (Photonic Immobilization Technique, PIT based on the UV irradiation of the antibodies, whereas a simple protocol provided by the manufacturer is applied to functionalize the gold nanoparticles. Thus, in a non-competitive approach, the small analyte is made detectable by weighing it down through a "sandwich protocol" with a second antibody tethered to heavy gold nanoparticles. The immunosensor has been proved to be effective against the parathion while showing no cross reaction when a mixture of compounds very similar to parathion is analyzed.The immunosensor described in this paper can be easily applied to any small molecule for which polyclonal antibodies are available since both the functionalization procedure of the QCM probe surface and gold nanoparticle can be applied to any IgG, thereby making our device of general application in terms of target analyte.

Quartz crystal microbalance sensor using ionophore for ammonium ion detection.

Science.gov (United States)

Kosaki, Yasuhiro; Takano, Kosuke; Citterio, Daniel; Suzuki, Koji; Shiratori, Seimei

2012-01-01

Ionophore-based quartz crystal microbalance (QCM) ammonium ion sensors with a detection limit for ammonium ion concentrations as low as 2.2 microM were fabricated. Ionophores are molecules, which selectively bind a particular ion. In this study, one of the known ionophores for ammonium, nonactin, was used to detect ammonium ions for environmental in-situ monitoring of aquarium water for the first time. To fabricate the sensing films, poly(vinyl chloride) was used as the matrix for the immobilization of nonactin. Furthermore, the anionic additive, tetrakis (4-chlorophenyl) borate potassium salt and the plasticizer dioctyl sebacate were used to enhance the sensor properties. The sensor allowed detecting ammonium ions not only in static solution, but also in flowing water. The sensor showed a nearly linear response with the increase of the ammonium ion concentration. The QCM resonance frequency increased with the increase of ammonium ion concentration, suggesting a decreasing weight of the sensing film. The detailed response mechanism could not be verified yet. However, from the results obtained when using a different plasticizer, nitrophenyl octyl ether, it is considered that this effect is caused by the release of water molecules. Consequently, the newly fabricated sensor detects ammonium ions by discharge of water. It shows high selectivity over potassium and sodium ions. We conclude that the newly fabricated sensor can be applied for detecting ammonium ions in aquarium water, since it allows measuring low ammonium ion concentrations. This sensor will be usable for water quality monitoring and controlling.

Establishing linear solvation energy relationships between VOCs and monolayer-protected gold nanoclusters using quartz crystal microbalance.

Science.gov (United States)

Li, Chi-Lin; Lu, Chia-Jung

2009-08-15

Linear solvation energy relationships (LSERs) have been recognized as a useful model for investigating the chemical forces behind the partition coefficients between vapor molecules and absorbents. This study is the first to determine the solvation properties of monolayer-protected gold nanoclusters (MPCs) with different surface ligands. The ratio of partition coefficients/MPC density (K/rho) of 18 volatile organic compounds (VOCs) for four different MPCs obtained through quartz crystal microbalance (QCM) experiments were used for the LSER model calculations. LSER modeling results indicate that all MPC surfaces showed a statistically significant (pattraction, 4-methoxythiophenol-capped MPCs can also interact with polar organics (s=1.04). Showing a unique preference for the hydrogen bond basicity of vapors (b=1.11), 2-benzothiazolethiol-capped MPCs provide evidence of an intra-molecular, proton-shift mechanism on surface of nano-gold.

Protein Adsorption to Titanium and Zirconia Using a Quartz Crystal Microbalance Method

Directory of Open Access Journals (Sweden)

You Kusakawa

2017-01-01

Full Text Available Protein adsorption onto titanium (Ti or zirconia (ZrO2 was evaluated using a 27 MHz quartz crystal microbalance (QCM. As proteins, fibronectin (Fn, a cell adhesive protein, and albumin (Alb, a cell adhesion-inhibiting protein, were evaluated. The Ti and ZrO2 sensors for QCM were characterized by atomic force microscopy and electron probe microanalysis observation, measurement of contact angle against water, and surface roughness. The amounts of Fn and Alb adsorbed onto the Ti and ZrO2 sensors and apparent reaction rate were obtained using QCM measurements. Ti sensor showed greater adsorption of Fn and Alb than the ZrO2 sensor. In addition, amount of Fn adsorbed onto the Ti or ZrO2 sensors was higher than that of Alb. The surface roughness and hydrophilicity of Ti or ZrO2 may influence the adsorption of Fn or Alb. With regard to the adsorption rate, Alb adsorbed more rapidly than Fn onto Ti. Comparing Ti and ZrO2, Alb adsorption rate to Ti was faster than that to ZrO2. Fn adsorption will be effective for cell activities, but Alb adsorption will not. QCM method could simulate in vivo Fn and Alb adsorption to Ti or ZrO2.

Optical properties and thermal stability of germanium oxide (GeO2) nanocrystals with α-quartz structure

International Nuclear Information System (INIS)

Ramana, C.V.; Carbajal-Franco, G.; Vemuri, R.S.; Troitskaia, I.B.; Gromilov, S.A.; Atuchin, V.V.

2010-01-01

Germanium dioxide (GeO 2 ) crystals were prepared by a chemical precipitation method at a relatively low-temperature (100 o C). The grown crystals were characterized by studying their microstructure, optical properties and thermal stability. The results indicate that the grown GeO 2 crystals exhibit α-quartz type crystal structure. The lattice parameters obtained from XRD were a = 4.987(4) A and c = 5.652(5) A. Electron microscopy analysis indicates a high structural quality of GeO 2 crystals grown using the present approach. Optical absorption measurements indicate a direct bandgap of 5.72 eV without any additional bands arising from localized or defect states. Thermogravimetric measurements indicate the temperature stability of the grown GeO 2 nanocrystals. Microscopic analysis coupled with energy dispersive X-ray spectroscopy of the GeO 2 crystals with α-quartz type crystal structure indicates their stability in chemical composition up to a temperature of 400 deg. C. The surface morphology of GeO 2 crystals, however, found to be changing with the increase in temperature.

Resonant frequency function of thickness-shear vibrations of rectangular crystal plates.

Science.gov (United States)

Wang, Ji; Yang, Lijun; Pan, Qiaoqiao; Chao, Min-Chiang; Du, Jianke

2011-05-01

The resonant frequencies of thickness-shear vibrations of quartz crystal plates in rectangular and circular shapes are always required in the design and manufacturing of quartz crystal resonators. As the size of quartz crystal resonators shrinks, for rectangular plates we must consider effects of both length and width for the precise calculation of resonant frequency. Starting from the three-dimensional equations of wave propagation in finite crystal plates and the general expression of vibration modes, we obtained the relations between frequency and wavenumbers. By satisfying the major boundary conditions of the dominant thickness-shear mode, three wavenumber solutions are obtained and the frequency equation is constructed. It is shown the resonant frequency of thickness-shear mode is a second-order polynomial of aspect ratios. This conforms to known results in the simplest form and is applicable to further analytical and experimental studies of the frequency equation of quartz crystal resonators.

In situ measurement of the mass concentration of flame-synthesized nanoparticles using quartz-crystal microbalance

International Nuclear Information System (INIS)

Hevroni, A; Golan, H; Fialkov, A; Tsionsky, V; Markovich, G; Cheskis, S; Rahinov, I

2011-01-01

A novel in situ method for measurement of mass concentration of nanoparticles (NPs) formed in flames is proposed. In this method, the deposition rate of NPs collected by a molecular beam sampling system is measured by quartz-crystal microbalance (QCM). It is the only existing method which allows direct measurement of NP mass concentration profiles in flames. The feasibility of the method was demonstrated by studying iron oxide NP formation in low-pressure methane/oxygen/nitrogen flames doped with iron pentacarbonyl. The system was tested under fuel-lean and fuel-rich flame conditions. Good agreement between measured QCM deposition rates and their estimations obtained by the transmission electron microscopy analysis of samples collected from the molecular beam has been demonstrated. The sensitivity of the method is comparable to that of particle mass spectrometry (PMS). Combination of the QCM technique with PMS and/or optical measurements can provide new qualitative information which is important for elucidation of the mechanisms governing the NP flame synthesis

Tool wear of a single-crystal diamond tool in nano-groove machining of a quartz glass plate

International Nuclear Information System (INIS)

Yoshino, Masahiko; Nakajima, Satoshi; Terano, Motoki

2015-01-01

Tool wear characteristics of a diamond tool in ductile mode machining are presented in this paper. Nano-groove machining of a quartz glass plate was conducted to examine the tool wear rate of a single-crystal diamond tool. Effects of lubrication on the tool wear rate were also evaluated. A numerical simulation technique was developed to evaluate the tool temperature and normal stress acting on the wear surface. From the simulation results it was found that the tool temperature does not increase during the machining experiment. It is also demonstrated that tool wear is attributed to the abrasive wear mechanism, but the effect of the adhesion wear mechanism is minor in nano-groove machining. It is found that the tool wear rate is reduced by using water or kerosene as a lubricant. (paper)

Effect of pre-dose irradiation in the quartz and its use for archaelogical dating

International Nuclear Information System (INIS)

Yukimitu, K.

1985-01-01

The technique of pre-dose for dating ceramics, using the thermoluminescent properties of quartz is presented. The behavior of thermoluminescent (TL) sensitivity of the 110 0 C peak of Brazilian quartz, in its geologic state, submitted to thermal treatments from 600 to 900 0 C, is studied. The samples were tritured for separating the quartz crystals from clay. The quartz grains were submitted to leaching with chloric acid solution followed by leaching with running water. The samples were irradiated in laboratory, with gamma radiation using Co-60 and Cs-137 sources, for calibration. A sensitivity enhancement rate of 2% per rad was observed for samples annealed at 900 0 C, was observed. (M.C.K.) [pt

Quartz crystal microbalance gas sensor with nanocrystalline diamond sensitive layer

Czech Academy of Sciences Publication Activity Database

Varga, Marián; Laposa, A.; Kulha, Pavel; Kroutil, J.; Husák, M.; Kromka, Alexander

2015-01-01

Roč. 252, č. 11 (2015), s. 2591-2597 ISSN 0370-1972 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:68378271 Keywords : gas sensor * nanocrystalline diamond * quartz resonator * thickness shear mode Subject RIV: JB - Sensor s, Measurment, Regulation Impact factor: 1.522, year: 2015

Separate measurement of the density and viscosity of a liquid using a quartz crystal microbalance based on admittance analysis (QCM-A)

International Nuclear Information System (INIS)

Itoh, Atsushi; Ichihashi, Motoko

2011-01-01

We previously used a quartz crystal microbalance (QCM) to identify a frequency f 2 that allows measurement of the mass load without being affected by the viscous load of a liquid in the liquid phase. Here, we determined that frequency in order to separately measure the density and viscosity of a Newtonian liquid. Martin et al separately measured the density and viscosity of a liquid by immersing two quartz resonators, i.e. a smooth-surface resonator and a textured-surface resonator, in the liquid. We used a QCM based on admittance analysis (QCM-A) in the current study to separately measure the viscosity and density of a liquid using only a textured-surface resonator. In the current experiments, we measured the density and viscosity of 500 µl of 10%, 30%, and 50% aqueous glycerol solutions and compared the measured values to reference values. The density obtained had an error of ±1.5% of reference values and the viscosity had an error of about ±5% of reference values. Similar results were obtained with 500 µl of 10%, 30%, and 50% ethanol solutions. Measurement was possible with a quartz resonator, so measurements were made with even smaller samples. The density and viscosity of a liquid were successfully determined with an extremely small amount of liquid, i.e. 10 µl, with almost the same precision as when using 500 µl of the liquid

Identification of color development potential of quartz by Raman spectroscopy

International Nuclear Information System (INIS)

Alkmim, Danielle G.; Lameiras, Fernando S.; Almeida, Frederico O.T.

2013-01-01

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 -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)

Identification of Color Development Potential of Quartz by Raman Spectroscopy

International Nuclear Information System (INIS)

Gomides Alkmim, D.; Soares Lameiras, F.

2013-01-01

Colorless quartz is usually exposed to ionizing radiation (gamma rays or high energy electron beams) in order to acquire different colors for jewelry. This is due to the presence of traces of some elements such as aluminum, iron, hydrogen, lithium, or sodium, which are responsible for the extrinsic colors developed after irradiation. Most quartz crystals are extracted colorless from nature and it is necessary to separate those that can develop colors from those that cannot. This can be done through irradiation tests, which take a long time. Other option is to collect the infrared signature of colorless quartz. However, infrared spectroscopic analysis 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 -1 was observed, only along the c axis of a prasiolite excited by a high power 514 nm laser. This band was nor observed in quartz samples that do not develop color after irradiation, hence requiring further studies. (Author)

Crystallization Stages of the Bishop Tuff Magma Body Recorded in Crystal Textures in Pumice Clasts

Energy Technology Data Exchange (ETDEWEB)

Pamukcu, Ayla; Gualda, Guilherme A.R.; Anderson, Jr. , Alfred T. (Vanderbilt); (UC)

2012-07-25

The Bishop Tuff is a giant silicic ignimbrite erupted at 0.76 Ma in eastern California, USA. Five pumice clasts from the late-erupted Bishop Tuff (Aeolian Buttes) were studied in an effort to better understand the pre- and syn-eruptive history of the Bishop magma body and place constraints on the timescales of its existence. This study complements and expands on a previous study that focused on early-erupted Bishop Tuff pumice clasts. Bulk densities of pumice clasts were measured using an immersion method, and phenocryst crystal contents were determined using a sieving and winnowing procedure. X-ray tomography was used to obtain qualitative and quantitative textural information, particularly crystal size distributions (CSDs). We have determined CSDs for crystals ranging in size from {approx}10 to {approx}1000 {micro}m for three groups of mineral phases: magnetite ({+-}ilmenite), pyroxene + biotite, quartz + feldspar. Similar to early-erupted pumice, late-erupted pumice bulk density and crystal contents are positively correlated, and comparison of crystal fraction vs size trends suggests that the proportion of large crystals is the primary control on crystallinity. Porosity is negatively correlated with crystal content, which is difficult to reconcile with closed-system crystallization. Magnetite and pyroxene + biotite size distributions are fractal in nature, often attributed to fragmentation; however, crystals are mostly whole and euhedral, such that an alternative mechanism is necessary to explain these distributions. Quartz + feldspar size distributions are kinked, with a shallow-sloped log-linear section describing large crystals (> 140 {micro}m) and a steep-sloped log-linear section describing small crystals (< 140 {micro}m). We interpret these two crystal populations as resulting from a shift in crystallization regime. We suggest that the shallow-sloped section describes a pre-eruptive quartz + feldspar growth-dominated regime, whereas the steep

Plasma-assisted quartz-to-quartz direct bonding for the fabrication of a multilayered quartz template for nanoimprint lithography

International Nuclear Information System (INIS)

Lee, Jihye; Ali, Altun; Kim, Ki-don; Choi, Dae-guen; Choi, Jun-Hyuk; Jeong, Jun-ho; Kim, Jae-Hyun

2010-01-01

In this paper, a low-temperature plasma-assisted process is developed to realize a uniform, ultraviolet (UV) transparent and chemically inert quartz-to-quartz direct bonding. Two sets of pretests are performed in order to understand how the bond surface energy changes with the plasma exposure time and the wet etching of quartz, respectively. The developed technique is used to fabricate a multilayered quartz template for UV nanoimprint lithography (UV-NIL). The multilayered quartz template is fabricated by bonding a square piece of a standard quartz wafer, which is about 625 µm in thickness, to a wet-etched 6.35 mm thick quartz photomask plate. A fabricated multilayered template is loaded to the commercial UV-NIL tool Imprio(TM) 100, and NIL was performed successfully. The developed direct bonding technique makes it possible for standard quartz wafers, which are compatible with high-resolution semiconductor fabrication processes, to be utilized as the templates in commercial UV-NIL machines with enhanced mechanical stability.

A novel type of electrochemical sensor based on ferromagnetic carbon-encapsulated iron nanoparticles for direct determination of hemoglobin in blood samples.

Science.gov (United States)

Matysiak, Edyta; Donten, Mikolaj; Kowalczyk, Agata; Bystrzejewski, Michal; Grudzinski, Ireneusz P; Nowicka, Anna M

2015-02-15

An effective, fast, facile and direct electrochemical method of determination of hemoglobin (Hb) in blood sample without any sample preparation is described. The method is accomplished by using the ferromagnetic electrode modifier (carbon-encapsulated iron nanoparticles) and an external magnetic field. The successful voltammetric determination of hemoglobin is achieved in PBS buffer as well as in the whole blood sample. The obtained results show the excellent electroactivity of Hb. The measurements are of high sensitivity and good reproducibility. The detection limit is estimated to be 0.7 pM. The electrochemical determination data were compared with the gravimetric data obtained with a quartz crystal microbalance. The agreement between these results is very good. The changes of the electrode surface morphology before and after Hb detection are monitored by electron microscopy. The functionality of the electrochemical sensor is tested with human and rat blood samples. The concentration of hemoglobin in the blood samples determined by using voltammetric/gravimetric detection is in perfect agreement with the data obtained from typical clinical analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

Determination of the potentiostatic stability of PEMFC electro catalysts at elevated temperatures

NARCIS (Netherlands)

Dam, V.A.T.; Jayasayee, K.; Bruijn, de F.A.

2009-01-01

The electrochemical stability of platinum on carbon catalyst (Hispec TM 4000, Johnson Matthey) has been investigated predominantly at constant potentials ranging from 0.95 to 1.25 V at elevated temperatures. By combining a quartz crystal microbalance (QCM) with electrochemical techniques, dynamic

Determination of thermodynamic parameters for enolization reaction of malonic and metylmalonic acids by using quartz crystal microbalance

Directory of Open Access Journals (Sweden)

Minoru Yoshimoto

2016-06-01

Full Text Available We investigated the process of a bromination reaction of malonic acid and methylmalonic acid in the Belousov-Zhabotinsky reaction by using a quartz crystal microbalance (QCM. The process involves an enolization reaction as a rate-determining step. We found that, in the step, the variation of Br2 concentration induced an exactly quantitative shift of a resonant frequency of the QCM, based on the change of the surface mass on the QCM and the solution viscosity and density. This new finding enabled us to estimate the reaction rate constants and the thermodynamic parameters of the enolization reaction due to a QCM measurement. The values measured by the QCM were in good agreement with those measured by a UV-spectrophotometer. As a result, we succeeded to develop a new measurement method of a nonlinear chemical reaction.

Multiparametric Characterization of Nonelectroactive Self-Assembled Monolayers During Their Formation

Czech Academy of Sciences Publication Activity Database

Kokoschka, Malte; Henry, J. B.; Bandarenka, A. S.

2013-01-01

Roč. 29, č. 31 (2013), s. 9909-9917 ISSN 0743-7463 Institutional support: RVO:61388963 Keywords : electrochemical impedance spectroscopy * quartz-crystal microbalance * single-crystal * gold electrodes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.384, year: 2013

Stability enhancement of an electrically tunable colloidal photonic crystal using modified electrodes with a large electrochemical potential window

Energy Technology Data Exchange (ETDEWEB)

Shim, HongShik [Samsung Advanced Institute of Technology, Yongin-Si, Gyeonggi-do (Korea, Republic of); Department of Chemistry, Seoul National University, Seoul (Korea, Republic of); Gyun Shin, Chang; Heo, Chul-Joon; Jeon, Seog-Jin; Jin, Haishun; Woo Kim, Jung; Jin, YongWan; Lee, SangYoon; Gyu Han, Moon, E-mail: moongyu.han@samsung.com, E-mail: jinklee@snu.ac.kr [Samsung Advanced Institute of Technology, Yongin-Si, Gyeonggi-do (Korea, Republic of); Lim, Joohyun; Lee, Jin-Kyu, E-mail: moongyu.han@samsung.com, E-mail: jinklee@snu.ac.kr [Department of Chemistry, Seoul National University, Seoul (Korea, Republic of)

2014-02-03

The color tuning behavior and switching stability of an electrically tunable colloidal photonic crystal system were studied with particular focus on the electrochemical aspects. Photonic color tuning of the colloidal arrays composed of monodisperse particles dispersed in water was achieved using external electric field through lattice constant manipulation. However, the number of effective color tuning cycle was limited due to generation of unwanted ions by electrolysis of the water medium during electrical switching. By introducing larger electrochemical potential window electrodes, such as conductive diamond-like carbon or boron-doped diamond, the switching stability was appreciably enhanced through reducing the number of ions generated.

Design and fabrication of an AT-cut quartz phononic Lamb wave resonator

International Nuclear Information System (INIS)

Hung, Chia-Hao; Liu, Ting-Wei; Wu, Tsung-Tsong; Wang, Wei-Shan; Esashi, Masayoshi; Lin, Yu-Ching; Sun, Jia-Hong; Chen, Yung-Yu

2013-01-01

This paper presents results on the design and fabrication of an AT-cut quartz Lamb wave resonator with phononic crystal (PC) reflective gratings. The deep reactive ion etching process with a laboratory-made etcher was utilized to fabricate PC structures of the AT-cut quartz Lamb wave resonator. The finite element method was adopted to calculate the PC band structure, effective reflective distance from the PC boundary and further the resonant modes and admittance of the phononic Lamb wave resonant cavity. Through the comparison studies between the experimental and simulated results, a design process for the AT-cut quartz phononic Lamb wave resonator was proposed. It is noted that by using the phononic reflectors, the size of the Lamb wave resonator can be reduced significantly. (paper)

Single-pulse and burst-mode ablation of gold films measured by quartz crystal microbalance

Science.gov (United States)

Andrusyak, Oleksiy G.; Bubelnik, Matthew; Mares, Jeremy; McGovern, Theresa; Siders, Craig W.

2005-02-01

Femtosecond ablation has several distinct advantages: the threshold energy fluence for the onset of damage and ablation is orders of magnitude less than for traditional nanosecond laser machining, and by virtue of the rapid material removal of approximately an optical penetration depth per pulse, femtosecond machined cuts can be cleaner and more precise than those made with traditional nanosecond or longer pulse lasers. However, in many materials of interest, especially metals, this limits ablation rates to 10-100 nm/pulse. We present the results of using multiple pulse bursts to significantly increase the per-burst ablation rate compared to a single pulse with the same integrated energy, while keeping the peak intensity of each individual pulse below the air ionization limit. Femtosecond ablation with pulses centered at 800-nm having integrated energy of up to 30 mJ per pulse incident upon thin gold films was measured via resonance frequency shifts in a gold-electrode-coated quartz-crystal oscillator. Measurements were performed using Michelson-interferometer-based burst generators, with up to 2 ns pulse separations, as well as pulse shaping by programmable acousto-optic dispersive filter (Dazzler from FastLite) with up to 2 ps pulse separations.

Real-time mass measurement of dust particles deposited on vessel wall in a divertor simulator using quartz crystal microbalances

International Nuclear Information System (INIS)

Tateishi, Mizuki; Koga, Kazunori; Katayama, Ryu; Yamashita, Daisuke; Kamataki, Kunihiro; Seo, Hyunwoong; Itagaki, Naho; Shiratani, Masaharu; Ashikawa, Naoko; Masuzaki, Suguru; Nishimura, Kiyohiko; Sagara, Akio

2015-01-01

We are developing a dust monitoring method using quartz crystal microbalances (QCMs) equipped with a dust eliminating filter. Here we report a dust eliminating ratio of the filter and first measurement results of the QCMs in a divertor simulator. The volume of spherical dust in unit area on the filter and QCM under the filter were 2.09 × 10 −9 and 1.22 × 10 −10 m 3 m −2 , respectively. Thus, the dust eliminating ratio of the filter is 94.2%. The QCM without the filter gives deposition rate due to radicals and dust particles, whereas the QCM with the filter gives deposition rate predominantly due to radicals. From the results, we deduce information of mass fraction of dust particles in deposits

Immersion angle dependence of the resonant-frequency shift of the quartz crystal microbalance in a liquid: effects of longitudinal wave.

Science.gov (United States)

Yoshimoto, Minoru; Kobirata, Satoshi; Aizawa, Hideo; Kurosawa, Shigeru

2007-06-19

We investigated the effects of the longitudinal wave on the immersion angle dependence of the resonant-frequency shift, deltaF, of the quartz crystal microbalance, QCM. In order to study exactly the effects, we employed the three types of cells: normal cell, cell with the glass beads and cell with sponge. The longitudinal wave exists in the normal cell. On the other hand, both the cell with the glass beads and the cell with sponge eliminate the longitudinal wave. As results, we have found that the tendencies of deltaF are the same in the three types of cells. That is, we conclude that the longitudinal wave does not have effects on the immersion angle dependence of deltaF.

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).

Imperfections study of the smoky quartz from Bahia by X-ray diffraction

International Nuclear Information System (INIS)

D'Aguiar Neto, M.M.F.

1974-01-01

X-ray diffraction techniques were used to study the type of point defects in Smoky quartz from Itambe and Vitoria da Conquista in Bahia. The power method, using the Seemann Bohlin camara (back refletion), was utilized in the analysis of the policrystals, while the monocrystals were studied by means of the precession camara. The positions occupied by the defects in the crystal net were calculated. The results show that while the defects of substitutional impurities predominate in the quartz from Itambe, in the quartz from Vitoria da Conquista the substitutional defects exist in comparable proportions that the interstital ones. Isochronous annealing curves, for both type of smoky quartz indicate an increase in the net parameter to temperature values above the annealing temperatures. Was formulated the hypothesis that providing a thermal energy greater than that of annealing is used, new interstitial defects would be created as a result of a thermic diffusion mechanism. (C.D.G.) [pt

Study on pivot-point vibration of molecular bond-rupture events by quartz crystal microbalance for biomedical diagnostics.

Science.gov (United States)

Yuan, Yong J; Jia, Renjie

2012-01-01

Bond-rupture scanning for biomedical diagnostics is examined using quartz crystal microbalance (QCM) experiments and microparticle mechanics modeling calculations. Specific and nonspecific interactions between a microparticle and its binding QCM surface can be distinguished by gradually increasing the amplitude of driving voltage applied to QCM and monitoring its frequency changes. This research proposes a mechanical model of interactions between biological molecules and a QCM substrate surface. The mechanical force required to break a biotin-streptavidin bond was calculated through a one-pivot-point bottom-up vibration model. The bond-rupture force increases with an increase of the microparticle radius, the QCM resonant frequency, and the amplitude of driving voltage applied to the QCM. The significance of the research on biological molecular bond rupture is extremely important in characterizing microbial (such as cells and virus) specificity, due to the force magnitude needed to break bonds using a transducer.

Fission track dating of authigenic quartz in red weathering crusts of carbonate rocks in Guizhou province

International Nuclear Information System (INIS)

Liu Xiuming; Wang Shijie; Zhang Feng

2004-01-01

The Cenozoic evolution history of Guizhou Province, which is located on the southeastern flank of the Qinghai-Tibet Plateau, is unclear because of the lack of sedimentation records. The red weathering crusts widespread on the Yunnan-Guizhou Plateau may bear critical information about their evolution history. This work firstly determined the ages of four red weathering crusts in eastern, central and northern Guizhou. The material used in fission track dating is well-crystallized quartz occurring in many in-situ weathering crusts of carbonate rocks. The results showed that the fission track ages of quartz vary over a wide range from 1 Ma to 25 Ma in the four profiles, significantly younger than the ages of Triassic and Cambrian parent rocks. In combination with the regionally geological evolution history during the period from 25 Ma to 1 Ma, the ages of quartz can exclude the possibility that the origin of quartz has nothing to do with primary clastic minerals in parent rocks, authigenesis during diagenesis and hydrothermal precipitation or replacement by volcanic activities. It is deduced that the well-crystallized quartz was precipitated from Si-rich weathering fluids during weathering processes of carbonate rocks. The recorded ages of quartz from the four profiles are consistent with the episodes of planation surfaces on the Qinghai-Tibet Plateau, the stages of red soil in the tropics of South China, the tectonically stable periods in Guizhou, and the ages of weathering in other parts of the world during the Cenozoic era. That is to say, the ages of authigenic quartz dated by the fission track method are well feasible and credible. (authors)

Proceedings of the fifth ISEAC triennial international conference on advances and recent trends in electrochemistry

International Nuclear Information System (INIS)

Aggarwal, Suresh K.; Guin, Saurav K.; Sharma, Manoj K.; Kamat, Jayshree V.; Ambolikar, Arvind S.

2013-01-01

The fifth international conference on advances and recent trends in electrochemistry was held during January 16-20, 2013 at Hyderabad. The topics covered under it were on electrochemistry and different branches of science and technology including nuclear science. Articles on electrochemical quartz crystal microbalance, scanning electrochemical microscope, electrochemical biosensors and ionic liquids are also included. Papers relevant to INIS are indexed separately

Fracture flow due to hydrothermally induced quartz growth

Science.gov (United States)

Kling, Tobias; Schwarz, Jens-Oliver; Wendler, Frank; Enzmann, Frieder; Blum, Philipp

2017-09-01

Mineral precipitations are a common feature and limitation of initially open, permeable rock fractures by forming sealing structures or secondary roughness in open voids. Hence, the objective of this numerical study is the evaluation of hydraulic properties of fractures sealed by hydrothermally induced needle and compact quartz growth. Phase-field models of progressive syntaxial and idiomorphic quartz growth are implemented into a fluid flow simulation solving the Navier-Stokes equation. Flow simulations for both quartz types indicate an obvious correlation between changes in permeability, fracture properties (e.g. aperture, relative roughness and porosity) and crystal growth behavior, which also forms distinct flow paths. Thus, at lower sealing stages initial fracture permeability significantly drops down for the 'needle fracture' forming highly tortuous flow paths, while the 'compact fracture' records a considerably smaller loss. Fluid flow in both sealing fractures most widely is governed by a ;parallel plate;-like cubic law behavior. However, the 'needle fracture' also reveals flow characteristics of a porous media. A semi-theoretical equation is introduced that links geometrical (am) with hydraulically effective apertures (ah) and the relative fracture roughness. For this purpose, a geometry factor α is introduced being α = 2.5 for needle quartz and α = 1.0 for compact quartz growth. In contrast to most common ah-am-relationships this novel formulation not only reveals more precise predictions for the needle (RMSE = 1.5) and the compact fractures (RMSE = 3.2), but also exhibit a larger range of validity concerning the roughness of the 'needle' (σ/am = 0-2.4) and the 'compact fractures' (σ/am = 0-1.8).

Deformation behavior of migmatites: insights from microstructural analysis of a garnet-sillimanite-mullite-quartz-feldspar-bearing anatectic migmatite at Rampura-Agucha, Aravalli-Delhi Fold Belt, NW India

Science.gov (United States)

Prakash, Abhishek; Piazolo, Sandra; Saha, Lopamudra; Bhattacharya, Abhijit; Pal, Durgesh Kumar; Sarkar, Saheli

2018-03-01

In the present study we investigate the microstructural development in mullite, quartz and garnet in an anatectic migmatite hosted within a Grenvillian-age shear zone in the Aravalli-Delhi Fold Belt. The migmatite exhibits three main deformation structures and fabrics (S1, S2, S3). Elongated garnet porphyroblasts are aligned parallel to the metatexite S2 layers and contain crenulation hinges defined by biotite-sillimanite-mullite-quartz (with S1 axial planar foliation). Microstructural evidence and phase equilibrium relations establish the garnet as a peritectic phase of incongruent melting by breakdown of biotite, sillimanite ± mullite and quartz at peak P-T of 8 kbar, 730 °C along a tight-loop, clockwise P-T path. Monazite dating establishes that the partial melting occurred between 1000 and 870 Ma. The absence of subgrains and systematic crystal lattice distortions in these garnets despite their elongation suggests growth pseudomorphing pre-existing 3-D networks of S1 biotite aggregates rather than high-temperature crystal plastic deformation which is noted in the S1 quartz grains that exhibit strong crystallographic preferred orientation (CPO), undulatory extinction and subgrains. Mode-I fractures in these garnet porphyroblasts induced by high melt pressure during late stage of partial melt crystallization are filled by retrograde biotite-sillimanite. Weak CPO and non-systematic crystal lattice distortions in the coarse quartz grains within the S2 leucosome domains indicate these crystallized during melt solidification without later crystal plastic deformation overprint. In the later stages of deformation (D3), strain was mostly accommodated in the mullite-biotite-sillimanite-rich restite domains forming S3 which warps around garnet and leucosome domains; consequently, fine-grained S3 quartz does not exhibit strong CPOs.

Role of Substrate on Quartz Cementation in Quartz Aggregates

Science.gov (United States)

Farver, J. R.; Winslow, D.; Onasch, C.

2010-12-01

Quartz cementation in quartz aggregates has been experimentally investigated. The starting material was disaggregated detrital quartz grains from the well-sorted, mature St. Peter Sandstone. The ‘as-is’ grains have patches of iron oxide coatings and some have euhedral overgrowths that contain iron oxide dust rims. In addition a set of experiments was run using grains that were cleaned by soaking in sodium hydrosulfite and sodium bisulfate solutions to remove exposed iron oxide coatings. Experimental charges consisted of amorphous silica powder (≈30 mg) to provide a source of silica for the quartz cement, AlCl3 powder (≈3 mg) to provide a tracer for Cathodoluminescence (CL) identification of cement formed during the experiment, 25 wt% NaCl brine solution (≈25 mg) to increase the silica solubility and to better mimic oil field brines, and the natural quartz grains (100-130 mg). The charges were weld-sealed in Au capsules and run in cold-seal pressure vessels at 250°C to 450°C at 150 MPa confining pressure for up to 8 weeks. After the experiments, the samples were vacuum impregnated with a low viscosity epoxy containing a blue dye. After curing, the sample charge was sawn in half along its long axis and one half was polished (to 1 micron diamond paste) for analysis. The nature and amount of quartz cement in the samples were determined by a combination of CL, light microscopy, and scanning electron microscopy. Photomosaics of the samples were created and the amount of cement, porosity, and average grain sizes were determined by point-counting. The cement formed during the experiment was easily recognized from the quartz grains (and previous overgrowths) by the difference in luminescence. The results indicate the amorphous silica powder provides a ready source for silica for quartz cementation due to its greater solubility than the quartz. The cementation rates are rapid (>14% cement formed in 2 weeks at 450°C and >7% in 8 weeks at 250°C). Compared to

The electrochemical transfer reactions and the structure of the iron|oxide layer|electrolyte interface

International Nuclear Information System (INIS)

Petrović, Željka; Metikoš-Huković, Mirjana; Babić, Ranko

2012-01-01

The thickness, barrier (protecting) and semiconducting properties of the potentiostatically formed oxide films on the pure iron electrode in an aqueous borate buffer solution were investigated by electrochemical quartz crystal nanobalance (EQCN), electrochemical impedance spectroscopy (EIS), and Mott–Schottky (MS) analysis. The thicknesses of the prepassive Fe(II)hydroxide layer (up to monolayer) nucleated on the bare iron surface and the passive Fe(II)/Fe(III) layer (up to 2 nm), deposited on the top of the first one, were determined using in situ gravimetry. Electronic properties of iron prepassive and passive films as well as ionic and electronic transfer reactions at the film|solution interface were discussed on the basis of a band structure model of the surface oxide film and the potential distribution at the interface. The anodic oxide film formation and cathodic decomposition are coupled processes and their reversible inter-conversion is mediated by the availability of free charge carriers on the electrode|solution interface. The structure of the reversible double layer at the iron oxide|solution interface was discussed based on the concept of the specific adsorption of the imidazolium cation on the negatively charged electrode surface at pH > pH pzc .

Scanning tunneling microscope-quartz crystal microbalance study of temperature gradients at an asperity contact.

Science.gov (United States)

Pan, L; Krim, J

2013-01-01

Investigations of atomic-scale friction frequently involve setups where a tip and substrate are initially at different temperatures. The temperature of the sliding interface upon contact has thus become a topic of interest. A method for detecting initial tip-sample temperature differences at an asperity contact is described, which consists of a scanning tunneling microscope (STM) tip in contact with the surface electrode of a quartz crystal microbalance (QCM). The technique makes use of the fact that a QCM is extremely sensitive to abrupt changes in temperature. In order to demonstrate the technique's capabilities, QCM frequency shifts were recorded for varying initial tip-substrate temperature differences as an STM tip was brought into and out of contact. The results are interpreted within the context of a recent model for thermal heat conduction at an asperity contact, and it is concluded that the transient frequency response is attributable to small changes in temperature close to the region of contact rather than a change in the overall temperature of the QCM itself. For the assumed model parameters, the results moreover reveal substantial temperature discontinuities at the boundary between the tip and the sample, for example, on the order of 10-15 °C for initial temperature differences of 20 °C.

Polyacrylonitrile nanofiber as polar solvent N,N-dimethyl formamide sensor based on quartz crystal microbalance technique

Science.gov (United States)

Rianjanu, A.; Julian, T.; Hidayat, S. N.; Suyono, E. A.; Kusumaatmaja, A.; Triyana, K.

2018-04-01

Here, we describe an N,N-dimethyl formamide (DMF) vapour sensor fabricated by coating polyacrylonitrile (PAN) nanofiber structured on quartz crystal microbalance (QCM). The PAN nanofiber sensors with an average diameter of 225 nm to 310 nm were fabricated via electrospinning process with different mass deposition on QCM substrate. The nanostructured of PAN nanofiber offers a high specific surface area that improved the sensing performance of nanofiber sensors. Benefiting from that fine structure, and high polymer-solvent affinity between PAN and DMF, the development of DMF sensors presented good response at ambient temperature. Since there is no chemical reaction between PAN nanofiber and DMF vapour, weak physical interaction such absorption and swelling were responsible for the sensing behavior. The results are indicating that the response of PAN nanofiber sensors has more dependency on the nanofiber structure (specific surface area) rather than its mass deposition. The sensor also showed good stability after a few days sensing. These findings have significant implications for developing DMF vapour sensor based on QCM coated polymer nanofibers.

The use of quartz crystal microbalance with dissipation (QCM-D) for studying nanoparticle-induced platelet aggregation

Science.gov (United States)

Santos-Martinez, Maria Jose; Inkielewicz-Stepniak, Iwona; Medina, Carlos; Rahme, Kamil; D’Arcy, Deirdre M; Fox, Daniel; Holmes, Justin D; Zhang, Hongzhou; Radomski, Marek Witold

2012-01-01

Interactions between blood platelets and nanoparticles have both pharmacological and toxicological significance and may lead to platelet activation and aggregation. Platelet aggregation is usually studied using light aggregometer that neither mimics the conditions found in human microvasculature nor detects microaggregates. A new method for the measurement of platelet microaggregation under flow conditions using a commercially available quartz crystal microbalance with dissipation (QCM-D) has recently been developed. The aim of the current study was to investigate if QCM-D could be used for the measurement of nanoparticle-platelet interactions. Silica, polystyrene, and gold nanoparticles were tested. The interactions were also studied using light aggregometry and flow cytometry, which measured surface abundance of platelet receptors. Platelet activation was imaged using phase contrast and scanning helium ion microscopy. QCM-D was able to measure nanoparticle-induced platelet microaggregation for all nanoparticles tested at concentrations that were undetectable by light aggregometry and flow cytometry. Microaggregates were measured by changes in frequency and dissipation, and the presence of platelets on the sensor surface was confirmed and imaged by phase contrast and scanning helium ion microscopy. PMID:22275839

Quantitative analyses of Streptococcus mutans biofilms with quartz crystal microbalance, microjet impingement and confocal microscopy.

Science.gov (United States)

Kreth, J; Hagerman, E; Tam, K; Merritt, J; Wong, D T W; Wu, B M; Myung, N V; Shi, W; Qi, F

2004-10-01

Microbial biofilm formation can be influenced by many physiological and genetic factors. The conventional microtiter plate assay provides useful but limited information about biofilm formation. With the fast expansion of the biofilm research field, there are urgent needs for more informative techniques to quantify the major parameters of a biofilm, such as adhesive strength and total biomass. It would be even more ideal if these measurements could be conducted in a real-time, non-invasive manner. In this study, we used quartz crystal microbalance (QCM) and microjet impingement (MJI) to measure total biomass and adhesive strength, respectively, of S. mutans biofilms formed under different sucrose concentrations. In conjunction with confocal laser scanning microscopy (CLSM) and the COMSTAT software, we show that sucrose concentration affects the biofilm strength, total biomass, and architecture in both qualitative and quantitative manners. Our data correlate well with previous observations about the effect of sucrose on the adherence of S. mutans to the tooth surface, and demonstrate that QCM is a useful tool for studying the kinetics of biofilm formation in real time and that MJI is a sensitive, easy-to-use device to measure the adhesive strength of a biofilm.

Adsorption of quantum dots onto polymer and Gemini surfactant films: a quartz crystal microbalance study.

Science.gov (United States)

Alejo, T; Merchán, M D; Velázquez, M M

2014-08-26

We used quartz crystal microbalance with dissipation to study the mechanical properties, the kinetics of adsorption, and the amount of CdSe quantum dots (QDs) adsorbed onto a SiO2 sensor, referred as bare sensor, onto the sensor modified with a film of the polymer poly(maleic anhydride-alt-1-octadecene), PMAO, or with a film of the Gemini surfactant ethyl-bis(dimethyl octadecyl ammonium bromide), abbreviated as 18-2-18. Results showed that when the sensor is coated with polymer or surfactant molecules, the coverage increases compared with that obtained for the bare sensor. On the other hand, rheological properties and kinetics of adsorption of QDs are driven by QD nanoparticles. Thus, the QD films present elastic behavior, and the elasticity values are independent of the molecule used as coating and similar to the elasticity value obtained for QDs films on the bare sensor. The QD adsorption is a two-step mechanism in which the fastest process is attributed to the QD adsorption onto the solid substrate and the slowest one is ascribed to rearrangement movements of the nanoparticles adsorbed at the surface.

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.

2011-01-01

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

Silver-compensated germanium center in α-quartz

International Nuclear Information System (INIS)

Laman, F.C.; Weil, J.A.

1977-01-01

A synthetic germanium-doped crystal of α-quartz was subjected to an electro-diffusion process (ca. 600 V/cm, 625 0 K), in which Ag + ions were introduced along the crystal's optic axis (c). A 9800 MHz electron paramagnetic resonance spectrum at room temperature, taken after room temperature X-irradiation, revealed the presence of a silver-compensated germanium center Asub(Ge-Ag) with large, almost isotropic 107 Ag and 109 Ag hyperfine splittings. Measurement of the spin-Hamiltonian discloses that a suitable model for the observed center utilizes germanium, substituted for silicon, with the accompanying silver interstitial in a nearby c-axis channel, and with electronic structure in which an appreciable admixture Ge 4+ - Ag 0 to Ge 3+ - Ag + exists. Estimates of the unpaired electron orbital are presented. (author)

Electrochemical quartz crystal microbalance analysis of the oxygen reduction reaction on Pt-based electrodes. Part 2: adsorption of oxygen species and ClO4(-) anions on Pt and Pt-Co alloy in HClO4 solutions.

Science.gov (United States)

Omura, J; Yano, H; Tryk, D A; Watanabe, M; Uchida, H

2014-01-14

To gain deeper insight into the role of adsorbed oxygenated species in the O2 reduction reaction (ORR) kinetics on platinum and platinum-cobalt alloys for fuel cells, we carried out a series of measurements with the electrochemical quartz crystal microbalance (EQCM) and the rotating disk electrode (RDE) in acid solution. The effects of anion adsorption on the activities for the ORR were first assessed in HClO4 and HF electrolyte solutions at various concentrations. In our previous work (Part 1), we reported that the perchlorate anion adsorbs specifically on bulk-Pt, with a Frumkin-Temkin isotherm, that is, a linear relationship between Δm and log[HClO4]. Here, we find that the specific adsorption on the Pt-skin/Pt3Co alloy was significantly stronger than that on bulk-Pt, in line with its modified electronic properties. The kinetically controlled current density j(k) for the O2 reduction at the Pt-skin/Pt3Co-RDE was about 9 times larger than that of the bulk-Pt-RDE in 0.01 M HClO4 saturated with air, but the j(k) values on Pt-skin/Pt3Co decreased with increasing [HClO4] more steeply than in the case of Pt, due to the blocking of the active sites by the specifically adsorbed ClO4(-). We have detected reversible mass changes for one or more adsorbed oxygen-containing species (Ox = O2, O, OH, H2O) on the Pt-skin/Pt3Co-EQCM and Pt-EQCM in O2-saturated and He-purged 0.01 M HClO4 solutions, in which the specific adsorption of ClO4(-) anions was negligible. The coverages of oxygen species θ(Ox) on the Pt-skin/Pt3Co in the potential range from 0.86 to 0.96 V in the O2-saturated solution were found to be larger than those on pure Pt, providing strong evidence that the higher O2 reduction activity on the Pt3Co is correlated with higher θ(Ox), contrary to the conventional view.

FABRICATION AND CHARACTERIZATION OF POLYANILINE-GRAPHENE COMPOSITE AS ELECTRODE IN ELECTROCHEMICAL CAPACITOR

Directory of Open Access Journals (Sweden)

H. Adelkhani

2016-06-01

Full Text Available In this study, polyaniline-graphene composites with different nano-structures are synthesized and the behaviour of the obtained composites serving as electrode materials in electrochemical capacitors is studied. The morphology, crystal structure, and thermal stability of the composites are examined using scanning electron microscopy (SEM, X-ray diffraction (XRD, and Thermal gravimetric analysis (TGA. Electrochemical properties are characterized by cyclic voltammetry (CV. According to the results, the obtained composites show different crystal structures and different thermal stabilities, and consequently different electrochemical capacities, when used as electrodes in electrochemical capacitors. A nano-fibre composite is shown to have a good degree of crystallization, 5.17% water content, 637oC degradation onset temperature, and 379 Fg-1 electrochemical capacity.

Lab-Scale Electrodeposition Behaviors of Pr(III) with Use of Quartz Cell in Molten LiCl-KCl Eutectic

Energy Technology Data Exchange (ETDEWEB)

Jee, Young Taek; Yun, Jong-Il [KAIST, Daejeon (Korea, Republic of)

2016-10-15

As electrorefining is proceeded, all actinides and lanthanides in metallic form are electrochemically oxidized and dissolved into the salt, while UCl{sub 3} in the salt is reduced and forms U-metal at solid cathodes. Since this unit process includes diverse actinides and recovers most of uranium, information on stream of nuclear materials and electrochemical condition inside of electrorefiner must continuously be notified not only for its performance assessment and process prediction but also for its safeguards. Currently, there are several computational models for electrorefiner (REFIN, ERAD, and etc.). However, the absence of model which reflects the change in surface area of cathode due to electrodeposition of UCl{sub 3} critically disturbs the precision of simulation. The change in surface area leads the change in current density, diffusion layer, potential and current gradient, and thus changes the entire electrochemical conditions in electrorefiner. In this paper, as a beginning step of investigating electrodeposition behavior of lanthanides and actinides, lab-scale electrodeposition experiments and methodological evaluation on the use of quartz cell are performed. In the lab-scale electrodeposition, sizes of quartz cell and deposited material became crucial factors for precise analysis of experiments. In a typical stabilized electrodeposition, CA diagram showed large plateau with reasonably increased magnitude of current due to the increase in surface area of working electrode. The amount of charge transferred (-61.55 C) can be utilized for concentration balance. According to ICP-OES, the decreased amount of bulk was 0.301 wt. % which was close to the expected decrease from the information of charge flow (0.29 wt. %). However, deposited material in contact with quartz wall in molten LiCl-KCl eutectic led a spontaneous reaction between each other. As an indicator of this undesired reaction, the cell became black, and enormous amount of charge was consumed. In

Stones of Light: The Use of Crystals in Maya Divination

DEFF Research Database (Denmark)

McGraw, John J.

2016-01-01

In this chapter, I aim to bridge the rewarding archaeological contributions from the earlier part of this volume to ethnographic work performed among contemporary Mayas, particularly as informed by ritual specialists. In considering the ritual use of quartz crystals by living Mayas we may gain...... of functional analysis that situate archaeological and ethnographic data without projecting a particularism onto Maya contexts that may be inappropriate given the local epistemologies. Finally, I draw from cognitive science and religious studies to present a theory regarding the popularity and importance...... of quartz crystals in ritual activity, not only among the Maya, but worldwide. It is hoped that the analyses presented not only clarify ideas regarding quartz crystals in divination, but more broadly address the nature and importance of scrying in Maya religion....

Superior environment resistance of quartz crystal microbalance with anatase TiO2/ZnO nanorod composite films

International Nuclear Information System (INIS)

Qiang, Wei; Wei, Li; Shaodan, Wang; Yu, Bai

2015-01-01

Graphical abstract: ZnO nanorod array being prepared by an in situ method on the QCM coated with Au film via hydrothermal process and surface modification with coated TiO 2 by sol–gel methods to form a superhydrophobic TiO 2 /ZnO composite film the anatase TiO 2 /ZnO nanorod composite film with a sharp, pencil-like structure exhibiting excellent superhydrophobicity (water contact angle of 155°), non-sticking water properties, and an autonomous cleaning property under UV irradiation. The anatase TiO 2 /ZnO nanorod composite film facilitates the precise measurement and extended lifetime of the QCM for the detection of organic gas molecules. - Highlights: • This work combines, for the first time, the advantage of the TiO 2 /ZnO composite film on photocatalysis and reversible super-hydrophobic and super-hydrophilic transition, and puts forward a solution to satisfy weatherability of quartz crystal microbalance in long-term application. • The anatase TiO 2 /ZnO nanorod composite film with pencil structure exhibit excellent super-hydrophobicity (water contact angle can reach 155°), no-sticking water properties and self-cleaning property under UV irradiation. • The photocatalysis and reversible super-hydrophobic and super-hydrophilic transition of the TiO 2 /ZnO nanorod composite film is stable in long-term application. - Abstract: The precise measurement of quartz crystal microbalance (QCM) in the detection and weighing of organic gas molecules is achieved due to excellent superhydrophobicity of a deposited film composite. Photocatalysis is utilized as a method for the self-cleaning of organic molecules on the QCM for extended long-term stability in the precision of the instrument. In this paper, ZnO nanorod array is prepared via in situ methods on the QCM coated with Au film via hydrothermal process. Subsequently, a TiO 2 /ZnO composite film is synthesized by surface modification with TiO 2 via sol–gel methods. Results show the anatase TiO 2 /ZnO nanorod

Interaction analysis of chimeric metal-binding green fluorescent protein and artificial solid-supported lipid membrane by quartz crystal microbalance and atomic force microscopy

International Nuclear Information System (INIS)

Prachayasittikul, Virapong; Na Ayudhya, Chartchalerm Isarankura; Hilterhaus, Lutz; Hinz, Andreas; Tantimongcolwat, Tanawut; Galla, Hans-Joachim

2005-01-01

Non-specific adsorption and specific interaction between a chimeric green fluorescent protein (GFP) carrying metal-binding region and the immobilized zinc ions on artificial solid-supported lipid membranes was investigated using the quartz crystal microbalance technique and the atomic force microscopy (AFM). Supported lipid bilayer, composed of octanethiol and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1,2-dioleoyl-sn-glycero-3-[N- (5-amino-1-carboxypentyl iminodiacetic acid)succinyl] (NTA-DOGS)-Zn 2+ , was formed on the gold electrode of quartz resonator (5 MHz). Binding of the chimeric GFP to zinc ions resulted in a rapid decrease of resonance frequency. Reversibility of the process was demonstrated via the removal of metal ions by EDTA. Nanoscale structural orientation of the chimeric GFP on the membrane was imaged by AFM. Association constant of the specific binding to metal ions was 2- to 3-fold higher than that of the non-specific adsorption, which was caused by the fluidization effect of the metal-chelating lipid molecules as well as the steric hindrance effect. This infers a possibility for a further development of biofunctionalized membrane. However, maximization is needed in order to attain closer advancement to a membrane-based sensor device

Blue and red thermoluminescence of natural quartz in the temperature region from -196 to 400deg. C

International Nuclear Information System (INIS)

Hashimoto, Tetsuo; Yanagawa, Yuji; Yawata, Takashi

2007-01-01

Quartz samples of three different origins were γ-irradiated with 20kGy at room temperature or at the temperature of liquid nitrogen (-196 deg. C), and analyzed by on-line TL-emission spectrometry over two temperature ranges: above 200deg. C (high-temperature region) and -196 to 200deg. C (low-temperature region). The emission spectra in the high-temperature region could be separated into intense blue TL (BTL) or red TL (RTL) properties. All quartz samples displayed more or less both properties of BTL and RTL in the low temperature region, shifting the BTL-emission spectra towards violet. Particularly, volcanically originated quartz (RTL, Medeshima) showed highly complex BTL and RTL peaks in the low-temperature region, and a stronger simple RTL peak in the high temperature. These complex glow-curve peaks are considered to reflect the presence of many crystal defects and much content of impurities in the volcanically formed quartz. In the glow-curve measurements, Brazilian quartz (quartz-vein origin) gave weak RTL and intense BTL in the low-temperature range, followed by faint emission of BTL in the high-temperature side. On the other hand, the radiation-induced colored (CC) part of a Madagascan crystal rock slice (hydrothermal origin) showed intense BTL together with slight RTL in the low temperatures, followed by strong BTL and appreciable strength of RTL in the high temperatures. The BTL-emission pattern (TL-color image) of a Madagascan slice showed a complementary relationship between irradiations at liquid-nitrogen temperature and at room temperature. To explain these radiation-induced phenomena from quartz, hydrogen radicals and Li + ions, derived from radiolysis products of OH-related impurities, could operate to eliminate the BTL centers by recombination below the room temperature

Crystallinity study of a faceted Brazilian quartz by X-rays topography

International Nuclear Information System (INIS)

Suzuki, C.K.; Farias, C.R.L.

1986-01-01

A characterization study of crystalline perfection along the Z-direction (from the base to the top) of a single crystal of natural quartz was conducted. A gradual and very significanty change of crystalline perfection with the transparency was revealed by X-ray topography and goniometric observation in samples cut along perpendicular to the Z-direction. (L.J.) [pt

OH-point defects in quartz in B- and Li-bearing systems and their application to pegmatites

Science.gov (United States)

Baron, M. A.; Stalder, R.; Konzett, J.; Hauzenberger, C. A.

2015-01-01

OH incorporation in quartz in Al-, B- and Li-bearing systems (granitic systems containing tourmaline or spodumene) was studied experimentally in order to investigate the effect of pressure, temperature and chemical impurities on the generation of OH-defects. High-pressure experiments were carried out at pressures between 5 and 25 kbar and temperatures between 800 and 900 °C, and OH-contents in quartz were calculated from IR absorption spectra measured on oriented quartz crystals. IR absorption features were assigned to impurity substitutions, such as AlOH (3,420, 3,379 and 3,315 cm-1) and BOH (3,595 cm-1), LiOH (3,483 cm-1), and hydrogarnet substitution (4H)Si defects (3,583 cm-1). Results indicate a negative correlation of incorporated Al-specific OH-defect content versus pressure (630 ± 130 wt ppm H2O at 5 kbar to 102 ± 6 wt ppm H2O at 25 kbar), but no clear correlation of B-specific OH-defects with pressure. In runs initially containing spodumene, virtually OH-free quartzes were observed at pressures ≥10 kbar, where impurity cations compensate each other forming an anhydrous eucryptite-defect component. In contrast, at 5 kbar, both Li- ad Al-specific OH-defects are observed (corresponding to 470 ± 75 wt ppm H2O). Results from this study may therefore be used to monitor formation conditions of quartz in terms of pressure and trace metal saturation of the crystallizing petrological system. IR spectra obtained from natural quartz grains from a tourmaline-bearing pegmatite exhibit B- and Al-related OH-bands. The B-related OH-band is also exhibited in quartz from a tourmaline + spodumene-bearing pegmatite. Li- and Al-related OH-bands, however, are subordinate or not observed at all in the spodumene-bearing system, which suggests that OH-vibrations do not reflect absolute Li-contents in quartz due to efficient coupled substitution involving Al. Data from experimental runs and natural specimens indicate that the B-related OH-band can be used as a rough proxy for

Fabrication of quartz microcylinders by laser interference lithography for angular optical tweezers

Science.gov (United States)

Santybayeva, Zhanna; Meghit, Afaf; Desgarceaux, Rudy; Teissier, Roland; Pichot, Frederic; de Marin, Charles; Charlot, Benoit; Pedaci, Francesco

2016-07-01

The use of optical tweezers (OTs) and spin angular momentum transfer to birefringent particles allows new mechanical measurements in systems where torque and rotation are relevant parameters at the single-molecule level. There is a growing interest in developing simple, fast, and inexpensive protocols to produce a large number of submicron scale cylinders of quartz, a positive uniaxial birefringent crystal, to be employed for such angular measurements in OTs. Here, we show that laser interference lithography, a method well known for its simplicity, fulfills these requirements and produces quartz cylindrical particles that we successfully use to apply and measure optical torque in the piconewton nm range in an optical torque wrench.

Peculiar Feldspar And Quartz Inclusions Within Zircons From Anorthosites, North Eastern Desert, Egypt

Science.gov (United States)

Eliwa, H. A.; Dawoud, M. I.; Khalaf, I. M.; Negendank, J. F.; Itaya, T.

2004-12-01

Zircons from three anorthosite outcrops along Wadi Dib area, north Eastern Desert of Egypt contain abundant and conspicuous inclusions of quartz, feldspar, amphibole and apatite. These anorthosites, as (50-100m thick) layers, represent the top of mafic-ultramafic intrusions exhibiting rhythmic layering visible by reputation of melanocratic and leucocratic layers. Field and microscopic studies exhibit that these anorthosites were affected by the action of residual magmatic solutions associated with the late stage crystallization of the younger granites, which modified their mineralogical composition. They are composed totally of plagioclase with subordinate amount of clinoenstatite, augite, amphibole, biotite, K-feldspar, and quartz. Accessories are magnetite, ilmenite, apatite and zircon. The abundance and the mode of occurrence of K-feldspar, quartz, and biotite with apatite and zircon among the megacrysts suggest their formation is ascribed to the interaction with the residual solutions. The microprobe data exhibit difference between feldspar and amphiboles contained herein zircons and those as anorthosite mineral constituents. The genetic relationship between zircons and their inclusions suggests later growth of zircons than inclusions and most probably at the final stage of rock modification. Zircons are magmatic and found in the interstitial feldspar and quartz among plagioclase megacrysts in aggregates or as individual grains. The microscopic and SEM images investigation exhibit that most zircons are subhedral to euhedral equant and prismatic crystals. Most zircons have same range of crystal morphologies and internal growth structures with predominance of prism /{100/} and pyramid /{101/} and occasionally prism /{110/} and pyramid /{111/}. No evidences for poly-faceted grains, inherited cores or later overgrowths were detected. CL images distinguished zircons with visible core-rim structures and others with regular and continuous growth zones contained herein

Titanium zoning and diffusion chronometry reveal dynamic and late-stage quartz growth in the Youngest Toba Tuff, Indonesia

Science.gov (United States)

Tierney, C. R.; Reid, M. R.; Burns, D. H.; Costa Rodriguez, F.; Chesner, C. A.

2017-12-01

The enormous 74 ka Youngest Toba Tuff (YTT) ejected 2800 km3 of compositionally zoned (68-77 wt.% SiO2) ignimbrite and co-ignimbrite ash. Titanium zoning within YTT quartz records a dynamic growth history, and sometimes concludes with a final growth stage under different conditions. We investigated the timescales of quartz growth using diffusion chronometry, and determined whether the last stage of crystallization was the result of a discrete and chamber-wide magmatic event. This work offers insight into the dynamics and timescales of storage and remobilization of voluminous silicic magmas - an important consideration for hazards assessment. High-resolution (1 µm steps) hyperspectral CL was mapped from 5-20 quartz crystals from each of five pumices spanning the YTT compositional spectrum. CL intensity was calibrated to Ti concentration via EPMA, and numerically modeled time-dependent diffusional relaxation curves where fit to concentration profiles across zone boundaries. CL-bright/high-Ti rims are found in quartz from all samples, but become less common and have lower Ti concentrations with increasing host pumice silica content (e.g., 70 ppm vs 50 ppm). Some large crystals contain distinct CL-bright interior zones with similar Ti concentration to the rims. Onset of growth of CL-bright rims commenced between 15 and 100 years before eruption, and interior bands between 30 and 1500 years. Neither rim nor interior ages correlate significantly with host pumice silica. Rim growth on quartz evidently occurred closer to eruption than a previous estimate of several decades to centuries for quartz from a single YTT pumice (Matthews et al., 2012). The similar timing for the onset of high-Ti quartz rim growth across all samples suggests a marked and temporally discrete magmatic event in the years to decades prior to eruption and may be recording the chamber-wide influence of magmatic recharge or remobilization. High-Ti interior zones likely record older recharge events that

Oxygen isotopic ratios in quartz as an indicator of provenance of dust

International Nuclear Information System (INIS)

Jackson, M.L.

1977-01-01

Quartz was isolated in the long range aerosol size range (fine silt, 1-10 μm in diameter) from atmospheric aerosols, wind-erosive soils, soil silts, shales, and Pacific pelagic sediments of the Northern and Southern Hemispheres, to trace their provenance or origin, as part of a study of dust mineral sequestering of 137 Cs and other products of nuclear fission. The oxygen isotopic ratio ( 18 O/ 16 O) was determined by mass spectrometry. The provenance has been established for this fine silt fraction which reflects the relative proportion of two classes of quartz source: (a) weathering of igneous and metamorphic rocks (high temperature origin and low 18 O/ 16 O ratio) and (b) of quartz crystallized in cherts and overgrowths (low temperature origin and high 18 O/ 16 O ratio). This quartz mixing ratio is a basic model or paradigm. Analyses of present day atmospheric aerosols and eolian-derived soils, Pacific pelagic sediments, and now-raised Phanerozoic marine sediments show that the Northern and Southern Hemispheres have separate large-scale reservoirs of the fine grain sizes that contribute to aerosol dusts. These can be identified by distinctive values of 18 O/ 16 O ratios of the quartz therein. The difference in quartz delta 18 O value in parts per thousand per ml ( 0 / 00 of about 12 +- 2 0 / 00 in Southern Hemisphere mixed detrital sediments and about 19 +- 2 0 / 00 in those of the Northern Hemisphere (for constant size, the 1-10 μm size fraction) results from the presence of a considerably larger proportion of quartz having low-temperature origin and higher delta 18 O values (chert, silica overgrowths, etc.) in the Northern Hemisphere reservoirs. The early paleoclimatic and paleogeochemical differences remain the control of the North-South Hemisphere difference in delta 18 O values in long-range aerosol sized quartz

Biomimetic Receptors for Bioanalyte Detection by Quartz Crystal Microbalances — From Molecules to Cells

Directory of Open Access Journals (Sweden)

Usman Latif

2014-12-01

Full Text Available A universal label-free detection of bioanalytes can be performed with biomimetic quartz crystal microbalance (QCM coatings prepared by imprinting strategies. Bulk imprinting was used to detect the endocrine disrupting chemicals (EDCs known as estradiols. The estrogen 17β-estradiol is one of the most potent EDCs, even at very low concentrations. A highly sensitive, selective and robust QCM sensor was fabricated for real time monitoring of 17β-estradiol in water samples by using molecular imprinted polyurethane. Optimization of porogen (pyrene and cross-linker (phloroglucinol levels leads to improved sensitivity, selectivity and response time of the estradiol sensor. Surface imprinting of polyurethane as sensor coating also allowed us to generate interaction sites for the selective recognition of bacteria, even in a very complex mixture of interfering compounds, while they were growing from their spores in nutrient solution. A double molecular imprinting approach was followed to transfer the geometrical features of natural bacteria onto the synthetic polymer to generate biomimetic bacteria. The use of biomimetic bacteria as template makes it possible to prepare multiple sensor coatings with similar sensitivity and selectivity. Thus, cell typing, e.g., differentiation of bacteria strains, bacteria growth profile and extent of their nutrition, can be monitored by biomimetic mass sensors. Obviously, this leads to controlled cell growth in bioreactors.

In-homogeneity in the pre-dose sensitization of the 110 °C TL peak in various quartz samples: The influence of annealing

International Nuclear Information System (INIS)

Polymeris, George S.; Oniya, Ebenezer O.; Jibiri, Nnamdi N.; Tsirliganis, Nestor C.; Kitis, George

2012-01-01

The pre-dose sensitization effect of the 110 °C TL glow-peak of quartz is a basic tool in thermoluminescence and optically stimulated luminescence dating and retrospective dosimetry. In the present work, a homogeneity study was performed on pre-dose sensitization in grains obtained from large quartz crystals samples collected from 10 different origins. The aliquot – to – aliquot scatter of the pre-dose sensitization of the 110 °C TL peak within each quartz crystal was monitored. The influence of the annealing on this scattering was also studied. Therefore, the investigation was applied to the un-fired “as is” samples as well as to samples annealed at 900 °C for 1 h following cooling to room temperature in air. The results showed that in the case of “as is” quartz the sensitization effect vary strongly within each aliquot of the same quartz sample. This strong variation is removed by both the high temperature annealing as well as heating up to 500 °C, involved in the TL measurements. These results are generally discussed in the framework of existing models and applications of the effect.

Electrochemical Multi-Coloration of Molybdenum Oxide Bronzes

International Nuclear Information System (INIS)

Lee, Sangmin; Saji, Viswanathan S.; Lee, Chiwoo

2013-01-01

We report a simple electrochemical approach in fabricating multiple colored molybdenum (Mo) oxide bronzes on the surface of a Mo-quartz electrode. A three step electrochemical batch process consisting of linear sweep voltammetry and anodic oxidation followed by cathodic reduction in neutral K 2 SO 4 electrolyte at different end potentials, viz. -0.62, -0.80 and -1.60 V (vs. Hg/HgSO 4 ) yielded red, blue and yellow colored bronzes. The samples produced were analyzed by XRD, EDS, and SIMS. The color variation was suggested to be associated with the cations intercalation into the oxide formed and the simultaneous structural changes that occurred during the cathodic reduction in neutral aqueous medium

Electrochemical Multi-Coloration of Molybdenum Oxide Bronzes

Energy Technology Data Exchange (ETDEWEB)

Lee, Sangmin; Saji, Viswanathan S.; Lee, Chiwoo [Korea Univ., Seoul (Korea, Republic of)

2013-08-15

We report a simple electrochemical approach in fabricating multiple colored molybdenum (Mo) oxide bronzes on the surface of a Mo-quartz electrode. A three step electrochemical batch process consisting of linear sweep voltammetry and anodic oxidation followed by cathodic reduction in neutral K{sub 2}SO{sub 4} electrolyte at different end potentials, viz. -0.62, -0.80 and -1.60 V (vs. Hg/HgSO{sub 4}) yielded red, blue and yellow colored bronzes. The samples produced were analyzed by XRD, EDS, and SIMS. The color variation was suggested to be associated with the cations intercalation into the oxide formed and the simultaneous structural changes that occurred during the cathodic reduction in neutral aqueous medium.

Study of quartz crystal microbalance NO2 sensor coated with sputtered indium tin oxide film

Science.gov (United States)

Georgieva, V.; Aleksandrova, M.; Stefanov, P.; Grechnikov, A.; Gadjanova, V.; Dilova, T.; Angelov, Ts

2014-12-01

A study of NO2 gas sorption ability of thin indium tin oxide (ITO) deposited on 16 MHz quartz crystal microbalance (QCM) is presented. ITO films are grown by RF sputtering of indium/tin target with weight proportion 95:5 in oxygen environment. The ITO films have been characterized by X-ray photoelectron spectroscopy measurements. The ITO surface composition in atomic % is defined to be: In-40.6%, Sn-4.3% and O-55%. The thickness and refractive index of the films are determined by ellipsometric method. The frequency shift of QCM-ITO is measured at different NO2 concentrations. The QCM-ITO system becomes sensitive at NO2 concentration >= 500 ppm. The sorbed mass for each concentration is calculated according the Sauerbrey equation. The results indicated that the 1.09 ng of the gas is sorbed into 150 nm thick ITO film at 500 ppm NO2 concentration. When the NO2 concentration increases 10 times the calculated loaded mass is 5.46 ng. The sorption process of the gas molecules is defined as reversible. The velocity of sorbtion /desorption processes are studied, too. The QCM coated with thin ITO films can be successfully used as gas sensors for detecting NO2 in the air at room temperature.

Study of quartz crystal microbalance NO2 sensor coated with sputtered indium tin oxide film

International Nuclear Information System (INIS)

Georgieva, V; Gadjanova, V; Angelov, Ts; Aleksandrova, M; Acad. Georgi Bonchev str.bl. 11, 1113, Sofia (Bulgaria))" data-affiliation=" (Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. Georgi Bonchev str.bl. 11, 1113, Sofia (Bulgaria))" >Stefanov, P; Acad. Georgi Bonchev str.bl. 11, 1113, Sofia (Bulgaria))" data-affiliation=" (Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. Georgi Bonchev str.bl. 11, 1113, Sofia (Bulgaria))" >Dilova, T; Grechnikov, A

2014-01-01

A study of NO 2 gas sorption ability of thin indium tin oxide (ITO) deposited on 16 MHz quartz crystal microbalance (QCM) is presented. ITO films are grown by RF sputtering of indium/tin target with weight proportion 95:5 in oxygen environment. The ITO films have been characterized by X-ray photoelectron spectroscopy measurements. The ITO surface composition in atomic % is defined to be: In-40.6%, Sn-4.3% and O-55%. The thickness and refractive index of the films are determined by ellipsometric method. The frequency shift of QCM-ITO is measured at different NO 2 concentrations. The QCM-ITO system becomes sensitive at NO 2 concentration ≥ 500 ppm. The sorbed mass for each concentration is calculated according the Sauerbrey equation. The results indicated that the 1.09 ng of the gas is sorbed into 150 nm thick ITO film at 500 ppm NO 2 concentration. When the NO 2 concentration increases 10 times the calculated loaded mass is 5.46 ng. The sorption process of the gas molecules is defined as reversible. The velocity of sorbtion /desorption processes are studied, too. The QCM coated with thin ITO films can be successfully used as gas sensors for detecting NO 2 in the air at room temperature

Nitrate-cancrinite precipitation on quartz sand in simulated Hanford tank solutions.

Science.gov (United States)

Bickmore, B R; Nagy, K L; Young, J S; Drexler, J W

2001-11-15

Caustic NaNO3 solutions containing dissolved Al were reacted with quartz sand at 89 degrees C to simulate possible reactions between leaked nuclear waste and primary subsurface minerals at the U.S. Department of Energy's Hanford site in Washington. Nitrate-cancrinite began to precipitate onto the quartz after 2-10 days, cementing the grains together. Estimates of the equilibrium constant for the precipitation reaction differ for solutions with 0.1 or 1.0 m OH- (log Keq = 30.4 +/- 0.8 and 36.2 +/- 0.6, respectively). The difference in solubility may be attributable to more perfect crystallinity (i.e., fewer stacking faults) in the higher-pH cancrinite structure. This is supported by electron micrographs of crystal morphology and measured rates of Na volatilization under an electron beam. Precipitate crystallinity may affect radionuclide mobility, because stacking faults in the cancrinite structure can diminish its zeolitic cation exchange properties. The precipitation rate near the onset of nucleation depends on the total Al and Si concentrations in solution. The evolution of experimental Si concentrations was modeled by considering the dependence of quartz dissolution rate on AI(OH)4- activity, cancrinite precipitation, and the reduction of reactive surface area of quartz due to coverage by cancrinite.

Transient effects during erosion of WN by deuterium ions studied with the quartz crystal microbalance technique

Energy Technology Data Exchange (ETDEWEB)

Berger, Bernhard M., E-mail: berger@iap.tuwien.ac.at [Institute of Applied Physics, TU Wien, Fusion@ÖAW, Wiedner Hauptstr. 8-10, 1040 Vienna (Austria); Stadlmayr, Reinhard [Institute of Applied Physics, TU Wien, Fusion@ÖAW, Wiedner Hauptstr. 8-10, 1040 Vienna (Austria); Meisl, Gerd [Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, 85748 Garching (Germany); Čekada, Miha [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Eisenmenger-Sittner, Christoph [Institute of Solid State Physics, TU Wien, Wiedner Hauptstr. 8-10, 1040 Vienna (Austria); Schwarz-Selinger, Thomas [Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, 85748 Garching (Germany); Aumayr, Friedrich, E-mail: aumayr@iap.tuwien.ac.at [Institute of Applied Physics, TU Wien, Fusion@ÖAW, Wiedner Hauptstr. 8-10, 1040 Vienna (Austria)

2016-09-01

Transient effects during erosion of polycrystalline tungsten-nitride (WN) films by mono-energetic deuterium projectiles are studied using a quartz crystal microbalance technique. The evolution of the mass removal rate of a 360 nm thin WN film under 500 eV/D and 1000 eV/D bombardment is investigated at a temperature of 465 K in situ and in real-time as a function of the deuterium fluence. The measurements are performed at a typical flux of 10{sup 18} m{sup −2} s{sup −1}. A strong dependency of the observed mass change rate on the deuterium fluence is found. The mass loss is initially higher than for pure tungsten (W) and drops with fluence, finally reaching the same steady state value as for pure W sputtering. Steady state surface conditions are obtained at a fluence of about 0.2 × 10{sup 23} D/m{sup 2} for 500 eV/D and 0.6 × 10{sup 23} D/m{sup 2} for 1000 eV/D. SDTrimSP simulations indicate a preferential removal of N and a corresponding W enrichment of the surface.

In-homogeneity in the pre-dose sensitization of the 110 Degree-Sign C TL peak in various quartz samples: The influence of annealing

Energy Technology Data Exchange (ETDEWEB)

Polymeris, George S., E-mail: polymers@auth.gr [Laboratory of Radiation Applications and Archaeological Dating, Department of Archaeometry and Physicochemical Measurements, Cultural and Educational Technology Institute, Athena, Research and Innovation Center in Information, Communication and Knowledge Technologies, Tsimiski 58, GR-67100 Xanthi (Greece); ISIK University, Faculty of Science and Arts, Physics Department, Sile 34980, Istanbul (Turkey); Oniya, Ebenezer O. [Laboratory of Radiation Applications and Archaeological Dating, Department of Archaeometry and Physicochemical Measurements, Cultural and Educational Technology Institute, Athena, Research and Innovation Center in Information, Communication and Knowledge Technologies, Tsimiski 58, GR-67100 Xanthi (Greece); Physics and Electronics Department, Adekunle Ajasin University, PMB 01 Akungba Akoko (Nigeria); Jibiri, Nnamdi N. [Department of Physics, University of Ibadan, Ibadan (Nigeria); Tsirliganis, Nestor C. [Laboratory of Radiation Applications and Archaeological Dating, Department of Archaeometry and Physicochemical Measurements, Cultural and Educational Technology Institute, Athena, Research and Innovation Center in Information, Communication and Knowledge Technologies, Tsimiski 58, GR-67100 Xanthi (Greece); Kitis, George [Aristotle University of Thessaloniki, Nuclear Physics Laboratory, 54124 Thessaloniki (Greece)

2012-03-01

The pre-dose sensitization effect of the 110 Degree-Sign C TL glow-peak of quartz is a basic tool in thermoluminescence and optically stimulated luminescence dating and retrospective dosimetry. In the present work, a homogeneity study was performed on pre-dose sensitization in grains obtained from large quartz crystals samples collected from 10 different origins. The aliquot - to - aliquot scatter of the pre-dose sensitization of the 110 Degree-Sign C TL peak within each quartz crystal was monitored. The influence of the annealing on this scattering was also studied. Therefore, the investigation was applied to the un-fired 'as is' samples as well as to samples annealed at 900 Degree-Sign C for 1 h following cooling to room temperature in air. The results showed that in the case of 'as is' quartz the sensitization effect vary strongly within each aliquot of the same quartz sample. This strong variation is removed by both the high temperature annealing as well as heating up to 500 Degree-Sign C, involved in the TL measurements. These results are generally discussed in the framework of existing models and applications of the effect.

Preparation of the electrochemically formed spinel-lithium manganese oxides

Energy Technology Data Exchange (ETDEWEB)

Katakura, Katsumi; Wada, Kohei; Kajiki, Yoshiyuki; Yamamoto, Akiko [Department of Chemical Engineering, Nara National College of Technology, 22 Yata-cho Yamotokoriyama, Nara 639-1080 (Japan); Ogumi, Zempachi [Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan)

2009-04-01

Electrochemically formed spinel-lithium manganese oxides were synthesized from manganese hydroxides prepared by a cathodic electrochemical precipitation from various concentrations of manganese nitrate solutions. Two types of manganese hydroxides were formed from diluted and concentrated Mn(NO{sub 3}){sub 2} aqueous solutions. Uniform and equi-sized disk shaped Mn(OH){sub 2} crystals of 0.2-5 {mu}m in diameter were obtained on a Pt substrate after the electrochemical precipitation from lower concentration of ranging from 2 mmol dm{sup -3} to 2 mol dm{sup -3} Mn(NO{sub 3}){sub 2} aq., while the grass blade-like precipitate which is ascribed to manganese hydroxide with 20-80 {mu}m long and 1-5 {mu}m wide were formed from concentrated Mn(NO{sub 3}){sub 2} aq. Both manganese hydroxides gave the electrochemically formed spinel-LiMn{sub 2}O{sub 4} onto a Pt sheet, which is ready for electrochemical measurement, after calcination of the Li incorporated precipitate at 750 C without any additives. While the shape and size of the secondary particle frameworks (aggregates) of the electrochemically formed spinel-LiMn{sub 2}O{sub 4} can be controlled by the electrolysis conditions, the nanostructured primary crystals of 200 nm in diameter were obtained in all cases except that the fiber-like nanostructured spinel-LiMn{sub 2}O{sub 4} crystals with 200 nm in diameter were obtained from concentrated Mn(NO{sub 3}){sub 2} aq. Though these two types of electrochemically formed spinel-LiMn{sub 2}O{sub 4} showed well-shaped CVs even in higher scan rates, it would be suitable for high power density battery applications. These behaviors are assumed to be ascribed to the crystal size and shape of the processed spinel-LiMn{sub 2}O{sub 4}. (author)

New Quartz Crystal Oscillators Using the Current-Feedback Operational Amplifier

OpenAIRE

Muhammad Taher Abuelma'atti; Ahmad Al-Ghazwani

2000-01-01

New crystal oscillators using the current-feedback operational-amplifier (CFOA) are presented. Each circuit uses one CFOA, a crystal and, at most, five externally connected passive elements. Experimental results are included.

Electrochemical and mass variation behaviour of rhodium oxide electrodes prepared by the polymeric precursor method

International Nuclear Information System (INIS)

Santos, M.C.; Oliveira, R.T.S.; Pereira, E.C.; Bulhoes, L.O.S.

2005-01-01

This paper describes an investigation of the charging processes of Rh 2 O 3 electrodes in acidic medium using Electrochemical Quartz Crystal Microbalance. The Rh 2 O 3 was prepared by the Pechini method. The microstructural characterization of the rhodium oxide was performed using Scanning Electron Microscopy and the structure was determined by X-ray diffraction. The Rh 2 O 3 oxidizes at potentials higher than 0.8 V. A mass loss of 60 ng was observed during the anodic sweep. The same amount is gained during the cathodic sweep indicating that the process is reversible. From the mass versus charge plots a slope of 8.5 g mol -1 is calculated. Considering a process that involves a two-electron transfer, the oxidation of Rh 2 O 3 to RhO 2 with the loss of a water molecule (18 g mol -1 ) is proposed

Investigation of the interaction between liquid and micro/nanostructured surfaces during condensation with quartz crystal microbalance

Science.gov (United States)

Su, Junwei

Dropwise condensation (DWC) on hydrophobic surfaces is attracting attention for its great potential in many industrial applications, such as steam power plants, water desalination, and de-icing of aerodynamic surfaces, to list a few. The direct dynamic characterization of liquid/solid interaction can significantly accelerate the progress toward a full understanding of the thermal and mass transport mechanisms during DWC processes. The research focuses on the development of a novel acoustic-based technique for analyzing the liquid/solid interactions of different condensations on micro- and nanostructured surfaces including DWC. hi addition. the newly developed technology was demonstrated for quantitatively sensing different wetting states of liquid on rough surfaces. First, different micro/nanostructures were fabricated on the quartz crystal microbalance (QCM), which serves as acoustic sensor. Polymethyl methacrylate (PMMA) micropillars, with varying heights from 6.03 to 25.02 microm, were fabricated on a quartz crystal microbalance (QCM) substrate by thermal nanoimprinting lithography to form pillar-based QCM (QCM-P). For nanostructured QCM. a copper layer was deposited on the QCM surface and then nanostructures of copper oxide (CuO) films were formed via chemical oxidation in an alkaline solution. Then, these surfaces were treated to make them superhydrophilic or superhydrophobic using oxygen plasma treatment or with coating of 1H,1 H,2H,2H-perfluorooctyl-trichlorosilane (PFOTS). Based on the geometry of these micro/nanostructures, the relationship between the frequency responses of QCM and the wetting states of these surfaces was theoretically investigated. Different theoretical models were established to describing the frequency shift of the micro- and nanostructured QCM in different wetting states. For the microstructured surface, the cantilever based model and a two-degree-of-freedom dynamic model were applied to predict the frequency shift of the QCM-P in

A comprehensive comparative study of the pre-dose effect for three quartz crystals of different origin

International Nuclear Information System (INIS)

Kitis, G.; Pagonis, V.; Chen, R.; Polymeris, G.

2006-01-01

The study of the thermoluminescence (TL) sensitivity of quartz due to heat and irradiation treatments is of importance in dating and retrospective dosimetry. A comprehensive comparative study of the pre-dose effect was carried out for three types of quartz of different origin. Complete TL vs. dose and sensitivity S vs. pre-dose curves were obtained for the dose range of 0.1 < D < 400 Gy. Additional complete sensitivity vs. pre-dose curves were obtained for samples which underwent a combined pre-dose irradiation and a subsequent heat treatment to 500 deg. C. Although the TL vs. dose curves showed very different behaviours, the sensitivity vs. pre-dose curves showed several common characteristics. The sensitivity vs. pre-dose curves showed abrupt changes ∼10 Gy. The sensitivity after a combined pre-dose irradiation and heat treatment to 500 deg. C showed a very gradual change in the whole dose range studied. These results are explained qualitatively by using the modified Zimmerman model for quartz. (authors)

Slaw extracted proton beam formation and monitoring for the ''QUARTZ'' setup

International Nuclear Information System (INIS)

Bushnin, Yu.B.; Gres', V.N.; Davydenko, Yu.P.

1982-01-01

The version of optical mode of the beam channel providing with simultaneous operating the experimental setups FODS and ''QUARTZ'' at consecutive usage of the slow extracted proton beam is reported. The ''QUARTZ'' setup beam diagnostics system comprises two subsystems: for measuring beam profile beam timing structure and beam intensity and operates in the beam extraction duration from 20 ns to few seconds at beam intensity from 10 10 to 5x10 12 protons/pulse. The ''QUARTZ'' setup represents a focusing crystal-diffraction spectrometer with 5-meter focal distance and Ge(Li) special construction detector. High efficiency target is applied in the setup. The ''QUARTZ'' setup is designed for studying exotic atoms produced by negative charged heavy particles (π, K, μ, P tilde) and atomic nuclei. Precise energy measurement of X ray transitions in such atoms is performed. For measuring beam geometric parameters 32-channel secondary emission chambers are used. As detector of beam intensity and timing structure of slow extracted beam the secondary emission chamber is employed. The principle circuit of current integrator is given. As data transmission line a 50-pair telephone cable is used. Information conversion into digital form and its subsequent processing is performed in the CAMAC system and the SM-3 computer. The proton beam full intensity measuring system provides with accuracy not worse than +-4.5% in the 10 10 -10 12 proton/sec range. The implemented optical mode of the beam channel and proton beam monitoring system permitted to begin fulfillment of the experimental program on the ''QUARTZ'' setup

Fluid Inclusion Analysis of other Host Minerals besides Quartz: Application to Granite-Related Quartz-Topaz Veins and Garnet Skarns in Porphyry Copper-Gold Ore Systems

OpenAIRE

Schlöglova, Katerina

2018-01-01

Fluid inclusions are the only available samples of paleo-fluids responsible for crystallization of hydrothermal minerals including ore phases. Analysis of fluid inclusions implicitly assumes that the inclusions have preserved their chemical composition since the time of their entrapment. There is, however, an increasing evidence from experimental work and analytical studies of natural samples showing that inclusions hosted in quartz – a ubiquitous host in many ore-forming systems – can experi...

Structural Dynamics and Evolution of Bismuth Electrodes during Electrochemical Reduction of CO ₂ in Imidazolium-Based Ionic Liquid Solutions

Energy Technology Data Exchange (ETDEWEB)

Medina-Ramos, Jonnathan [Chemical; Lee, Sang Soo [Chemical; Fister, Timothy T. [Chemical; Hubaud, Aude A. [Chemical; Sacci, Robert L.; Mullins, David R.; DiMeglio, John L. [Department; Pupillo, Rachel C. [Department; Velardo, Stephanie M. [Department; Lutterman, Daniel A.; Rosenthal, Joel [Department; Fenter, Paul [Chemical

2017-09-14

Real-time changes in the composition and structure of bismuth electrodes used for catalytic conversion of CO2 into CO were examined via X-ray absorption spectroscopy (including XANES and EXAFS), electrochemical quartz crystal microbalance (EQCM), and in situ X-ray reflectivity (XR). Measurements were performed with bismuth electrodes immersed in acetonitrile (MeCN) solutions containing a 1-butyl-3-methylimidazolium ([BMIM]+) ionic liquid promoter or electrochemically inactive tetrabutylammonium supporting electrolytes (TBAPF6 and TBAOTf). Altogether, these measurements show that bismuth electrodes are originally a mixture of bismuth oxides (including Bi2O3) and metallic bismuth (Bi0) and that the reduction of oxidized bismuth species to Bi0 is fully achieved under potentials at which CO2 activation takes place. Furthermore, EQCM measurements conducted during cyclic voltammetry revealed that a bismuth-coated quartz crystal exhibits significant shifts in resistance (ΔR) prior to the onset of CO2 reduction near -1.75 V vs Ag/AgCl and pronounced hysteresis in frequency (Δf) and ΔR, which suggests significant changes in roughness or viscosity at the Bi/[BMIM]+ solution interface. In situ XR performed on rhombohedral Bi (001) oriented films indicates that extensive restructuring of the bismuth film cathodes takes place upon polarization to potentials more negative than -1.6 V vs Ag/AgCl, which is characterized by a decrease of the Bi (001) Bragg peak intensity of ≥50% in [BMIM]OTf solutions in the presence and absence of CO2. Over 90% of the reflectivity is recovered during the anodic half-scan, suggesting that the structural changes are mostly reversible. In contrast, such a phenomenon is not observed for thin Bi (001) oriented films in solutions of tetrabutylammonium salts that do not promote CO2 reduction. Overall, these results highlight that Bi electrodes undergo significant potential-dependent chemical and structural transformations in the presence of [BMIM

Study on the electrochemical of the metal deposition from ionic liquids for lithium, titanium and dysprosium

International Nuclear Information System (INIS)

Berger, Claudia A.

2017-01-01

The thesis was aimed to the characterization of electrochemically deposited film of lithium, titanium and dysprosium on Au(111) from different ionic liquids, finally dysprosium on neodymium-iron-boron magnate for industrial applications. The investigation of the deposits were performed using cyclic voltametry, in-situ scanning tunneling microscopy, electrochemical quartz microbalance, XPS and Auger electron spectroscopy. The sample preparation is described in detail. The deposition rate showed a significant temperature dependence.

Ag+ implantation in Al2O3, LiNbO3 and quartz

International Nuclear Information System (INIS)

Rahmani, M.; Townsend, P.D.

1989-01-01

Silver implantation in insulators produces colloids whose growth is a function of ion dose, ion energy, implant temperature and crystal orientation. Data for three materials are compared. Colloid growth is favoured by higher energy implants at temperatures where the silver is mobile. Preferential diffusion along the Z axis of Al 2 O 3 , LiNbO 3 and quartz results in a higher fraction of the implanted silver ions appearing in the form of colloids for Y cut crystals than for those of Z cut. Annealing characteristics also show a strong dependence on crystal cut. For the LiNbO 3 the colloids in Z cut crystals anneal most rapidly whereas for Al 2 O 3 those in Y cut material are least stable, their loss being accompanied by a reduction in F centres. (author)

Peptide-membrane interactions of arginine-tryptophan peptides probed using quartz crystal microbalance with dissipation monitoring.

KAUST Repository

Rydberg, Hanna A

2014-04-18

Membrane-active peptides include peptides that can cross cellular membranes and deliver macromolecular cargo as well as peptides that inhibit bacterial growth. Some of these peptides can act as both transporters and antibacterial agents. It is desirable to combine the knowledge from these two different fields of membrane-active peptides into design of new peptides with tailored actions, as transporters of cargo or as antibacterial substances, targeting specific membranes. We have previously shown that the position of the amino acid tryptophan in the peptide sequence of three arginine-tryptophan peptides affects their uptake and intracellular localization in live mammalian cells, as well as their ability to inhibit bacterial growth. Here, we use quartz crystal microbalance with dissipation monitoring to assess the induced changes caused by binding of the three peptides to supported model membranes composed of POPC, POPC/POPG, POPC/POPG/cholesterol or POPC/lactosyl PE. Our results indicate that the tryptophan position in the peptide sequence affects the way these peptides interact with the different model membranes and that the presence of cholesterol in particular seems to affect the membrane interaction of the peptide with an even distribution of tryptophans in the peptide sequence. These results give mechanistic insight into the function of these peptides and may aid in the design of membrane-active peptides with specified cellular targets and actions.

Peptide-membrane interactions of arginine-tryptophan peptides probed using quartz crystal microbalance with dissipation monitoring.

KAUST Repository

Rydberg, Hanna A; Kunze, Angelika; Carlsson, Nils; Altgä rde, Noomi; Svedhem, Sofia; Nordé n, Bengt

2014-01-01

Membrane-active peptides include peptides that can cross cellular membranes and deliver macromolecular cargo as well as peptides that inhibit bacterial growth. Some of these peptides can act as both transporters and antibacterial agents. It is desirable to combine the knowledge from these two different fields of membrane-active peptides into design of new peptides with tailored actions, as transporters of cargo or as antibacterial substances, targeting specific membranes. We have previously shown that the position of the amino acid tryptophan in the peptide sequence of three arginine-tryptophan peptides affects their uptake and intracellular localization in live mammalian cells, as well as their ability to inhibit bacterial growth. Here, we use quartz crystal microbalance with dissipation monitoring to assess the induced changes caused by binding of the three peptides to supported model membranes composed of POPC, POPC/POPG, POPC/POPG/cholesterol or POPC/lactosyl PE. Our results indicate that the tryptophan position in the peptide sequence affects the way these peptides interact with the different model membranes and that the presence of cholesterol in particular seems to affect the membrane interaction of the peptide with an even distribution of tryptophans in the peptide sequence. These results give mechanistic insight into the function of these peptides and may aid in the design of membrane-active peptides with specified cellular targets and actions.

Rapid Crystallization of the Bishop Magma

Science.gov (United States)

Gualda, G. A.; Anderson, A. T.; Sutton, S. R.

2007-12-01

Substantial effort has been made to understand the longevity of rhyolitic magmas, and particular attention has been paid to the systems in the Long Valley area (California). Recent geochronological data suggest discrete magma bodies that existed for hundreds of thousands of years. Zircon crystallization ages for the Bishop Tuff span 100-200 ka, and were interpreted to reflect slow crystallization of a liquid-rich magma. Here we use the diffusional relaxation of Ti zoning in quartz to investigate the longevity of the Bishop magma. We have used such an approach to show the short timescales of crystallization of Ti-rich rims on quartz from early- erupted Bishop Tuff. We have now recognized Ti-rich cores in quartz that can be used to derive the timescales of their crystallization. We studied four samples of the early-erupted Bishop. Hand-picked crystals were mounted on glass slides and polished. Cathodoluminescence (CL) images were obtained using the electron microprobe at the University of Chicago. Ti zoning was documented using the GeoSoilEnviroCARS x-ray microprobe at the Advanced Photon Source (Argonne National Lab). Quartz crystals in all 4 samples include up to 3 Ti-bearing zones: a central core (50-100 μm in diameter, ca. 50 ppm Ti), a volumetrically predominant interior (~40 ppm Ti), and in some crystals a 50-100 μm thick rim (50 ppm Ti). Maximum estimates of core residence times were calculated using a 1D diffusion model, as the time needed to smooth an infinitely steep profile to fit the observed profile. Surprisingly, even for the largest crystals studied - ca. 2 mm in diameter - core residence times are less than 1 ka. Calculated growth rates imply that even cm-sized crystals crystallized in less than 10 ka. Crystal size distribution data show that crystals larger than 3 mm are exceedingly rare, such that the important inference is that the bulk of the crystallization of the early-erupted Bishop magma occurred in only a few thousand years. This timescale

Determination of the hexagonal network parameters of the quartz β using neutron multiple diffraction

International Nuclear Information System (INIS)

Campos, L.C.; Parente, C.B.R.; Mazzocchi, V.L.; Helene, O.

2000-01-01

In this work, neutron multiple diffraction is employed for the determination of the parameters a and c of the β-quartz hexagonal cell. This crystalline phase of silica (SiO 2 ) occurs in temperatures between ca. 846 and 1143 K. A β-quartz neutron multiple diffraction pattern has been used in the determinations. This pattern was obtained with a natural quartz single crystal heated to 1003 K. During the indexing of the pattern it was verified that most of the pairs of secondary reflections, which are responsible for the formation of peaks, could be classified as 'good for the determination of a' or 'good for the determination of c'. With this classification, it became possible to employ an iterative method for the determination of both parameters. After 8 cycles of iteration the values found for the parameters were a = 4.9964 +- 0.0018 and c = 5.46268 +- 0.00052 A. (author)

Wet-digestion of environmental sample using silver-mediated electrochemical method

International Nuclear Information System (INIS)

Kuwabara, Jun

2010-01-01

An application of silver-mediated electrochemical method to environmental samples as the effective digestion method for iodine analysis was tried. Usual digestion method for 129 I in many type of environmental sample is combustion method using quartz glass tube. Chemical yield of iodine on the combustion method reduce depending on the type of sample. The silver-mediated electrochemical method is expected to achieve very low loss of iodine. In this study, dried kombu (Laminaria) sample was tried to digest with electrochemical cell. At the case of 1g of sample, digestion was completed for about 24 hours under the electric condition of <10V and <2A. After the digestion, oxidized species of iodine was reduced to iodide by adding sodium sulfite. And then the precipitate of silver iodide was obtained. (author)

Real-time monitoring of peptic and tryptic digestions of bovine {beta}-casein using quartz crystal microbalance

Energy Technology Data Exchange (ETDEWEB)

Huenerbein, Andreas [Institute of Pharmaceutics and Biopharmaceutics, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120 Halle (Saale) (Germany)]. E-mail: andreas.huenerbein@pharmazie.uni-halle.de; Schmelzer, Christian E.H. [Institute of Pharmaceutics and Biopharmaceutics, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120 Halle (Saale) (Germany); Neubert, Reinhard H.H. [Institute of Pharmaceutics and Biopharmaceutics, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120 Halle (Saale) (Germany)

2007-02-12

In this study peptic and tryptic digestions of bovine {beta}-casein were investigated using quartz crystal microbalance (QCM). {beta}-Casein, which was used as a model protein, was immobilized on the surface of the QCM sensor where its degradation caused shifts in the resonant frequency. Atomic force microscopy was applied for the characterization of the protein layer. Different pH-values for peptic or tryptic digestions were chosen to visualize their effect on enzyme activity. Lower frequency shifts were observed at pH-values deviating from those at the maximum enzyme activity. In the case of the peptic digestion the frequency shift at pH 4 was more than 10 times smaller than those at pH 2. The frequency shifts for tryptic digestions at pH 5.4 and pH 6.4 were about two thirds compared to that obtained for the digestion at pH 7.4. The identification of peptides using MALDI-ToF mass spectrometry was used for verification of the proteolyses of the immobilized protein. Furthermore, it was shown that the QCM technique allows close observation of the effect of different pH-values on the immobilized casein layer. All in all, QCM facilitates the monitoring of the progress of enzymatic reactions in real-time.

Real-time monitoring of peptic and tryptic digestions of bovine β-casein using quartz crystal microbalance

International Nuclear Information System (INIS)

Huenerbein, Andreas; Schmelzer, Christian E.H.; Neubert, Reinhard H.H.

2007-01-01

In this study peptic and tryptic digestions of bovine β-casein were investigated using quartz crystal microbalance (QCM). β-Casein, which was used as a model protein, was immobilized on the surface of the QCM sensor where its degradation caused shifts in the resonant frequency. Atomic force microscopy was applied for the characterization of the protein layer. Different pH-values for peptic or tryptic digestions were chosen to visualize their effect on enzyme activity. Lower frequency shifts were observed at pH-values deviating from those at the maximum enzyme activity. In the case of the peptic digestion the frequency shift at pH 4 was more than 10 times smaller than those at pH 2. The frequency shifts for tryptic digestions at pH 5.4 and pH 6.4 were about two thirds compared to that obtained for the digestion at pH 7.4. The identification of peptides using MALDI-ToF mass spectrometry was used for verification of the proteolyses of the immobilized protein. Furthermore, it was shown that the QCM technique allows close observation of the effect of different pH-values on the immobilized casein layer. All in all, QCM facilitates the monitoring of the progress of enzymatic reactions in real-time

Probing adsorption of polyacrylamide-based polymers on anisotropic Basal planes of kaolinite using quartz crystal microbalance.

Science.gov (United States)

Alagha, Lana; Wang, Shengqun; Yan, Lujie; Xu, Zhenghe; Masliyah, Jacob

2013-03-26

Quartz crystal microbalance with dissipation (QCM-D) was applied to investigate the adsorption characteristics of polyacrylamide-based polymers (PAMs) on anisotropic basal planes of kaolinite. Kaolinite basal planes were differentiated by depositing kaolinite nanoparticles (KNPs) on silica and alumina sensors in solutions of controlled pH values. Adsorption of an in-house synthesized organic-inorganic Al(OH)3-PAM (Al-PAM) as an example of cationic hybrid PAM and a commercially available partially hydrolyzed polyacrylamide (MF1011) as an example of anionic PAM was studied. Cationic Al-PAM was found to adsorb irreversibly and preferentially on tetrahedral silica basal planes of kaolinite. In contrast, anionic MF1011 adsorbed strongly on aluminum-hydroxy basal planes, while its adsorption on tetrahedral silica basal planes was weak and reversible. Adsorption study revealed that both electrostatic attraction and hydrogen-bonding mechanisms contribute to adsorption of PAMs on kaolinite. The adsorbed Al-PAM layer was able to release trapped water overtime and became more compact, while MF1011 film became more dissipative as backbones stretched out from kaolinite surface with minimal overlapping. Experimental results obtained from this study provide clear insights into the phenomenon that governs flocculation-based solid-liquid separation processes using multicomponent flocculants of anionic and cationic nature.

A perspective on the structural studies of inner membrane electrochemical potential-driven transporters.

Science.gov (United States)

Lemieux, M Joanne

2008-09-01

Electrochemical potential-driven transporters represent a vast array of proteins with varied substrate specificities. While diverse in size and substrate specificity, they are all driven by electrochemical potentials. Over the past five years there have been increasing numbers of X-ray structures reported for this family of transporters. Structural information is available for five subfamilies of electrochemical potential-driven transporters. No structural information exists for the remaining 91 subfamilies. In this review, the various subfamilies of electrochemical potential-driven transporters are discussed. The seven reported structures for the electrochemical potential-driven transporters and the methods for their crystallization are also presented. With a few exceptions, overall crystallization trends have been very similar for the transporters despite their differences in substrate specificity and topology. Also discussed is why the structural studies on these transporters were successful while others are not as fruitful. With the plethora of transporters with unknown structures, this review provides incentive for crystallization of transporters in the remaining subfamilies for which no structural information exists.

Quartz-coesite-stishovite relations in shocked metaquartzites from the Vredefort impact structure, South Africa

Science.gov (United States)

Spray, John G.; Boonsue, Suporn

2018-01-01

Coesite and stishovite are developed in shock veins within metaquartzites beyond a radius of 30 km from the center of the 2.02 Ga Vredefort impact structure. This work focuses on deploying analytical field emission scanning electron microscopy, electron backscattered diffraction, and Raman spectrometry to better understand the temporal and spatial relations of these silica polymorphs. α-Quartz in the host metaquartzites, away from shock veins, exhibits planar features, Brazil twins, and decorated planar deformation features, indicating a primary (bulk) shock loading of >5 < 35 GPa. Within the shock veins, coesite forms anhedral grains, ranging in size from 0.5 to 4 μm, with an average of 1.25 μm. It occurs in clasts, where it displays a distinct jigsaw texture, indicative of partial reversion to a less dense SiO2 phase, now represented by microcrystalline quartz. It is also developed in the matrix of the shock veins, where it is typically of smaller size (<1 μm). Stishovite occurs as euhedral acicular crystals, typically <0.5 μm wide and up to 15 μm in length, associated with clast-matrix or shock vein margin-matrix interfaces. In this context, the needles occur as radiating or subparallel clusters, which grow into/over both coesite and what is now microcrystalline quartz. Stishovite also occurs as more blebby, subhedral to anhedral grains in the vein matrix (typically <1 μm). We propose a model for the evolution of the veins (1) precursory frictional melting in a microfault ( 1 mm wide) generates a molten matrix containing quartz clasts. This is followed by (2) arrival of the main shock front, which shocks to 35 GPa. This generates coesite in the clasts and in the matrix. (3) On initial shock release, the coesite partly reverts to a less dense SiO2 phase, which is now represented by microcrystalline quartz. (4) With continued release, stishovite forms euhedral needle clusters at solid-liquid interfaces and as anhedral crystals in the matrix. (5) With

MnO2 prepared by hydrothermal method and electrochemical performance as anode for lithium-ion battery.

Science.gov (United States)

Feng, Lili; Xuan, Zhewen; Zhao, Hongbo; Bai, Yang; Guo, Junming; Su, Chang-Wei; Chen, Xiaokai

2014-01-01

Two α-MnO2 crystals with caddice-clew-like and urchin-like morphologies are prepared by the hydrothermal method, and their structure and electrochemical performance are characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), galvanostatic cell cycling, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS). The morphology of the MnO2 prepared under acidic condition is urchin-like, while the one prepared under neutral condition is caddice-clew-like. The identical crystalline phase of MnO2 crystals is essential to evaluate the relationship between electrochemical performances and morphologies for lithium-ion battery application. In this study, urchin-like α-MnO2 crystals with compact structure have better electrochemical performance due to the higher specific capacity and lower impedance. We find that the relationship between electrochemical performance and morphology is different when MnO2 material used as electrochemical supercapacitor or as anode of lithium-ion battery. For lithium-ion battery application, urchin-like MnO2 material has better electrochemical performance.

Lattice location of gold in natural pyrite crystals

International Nuclear Information System (INIS)

Besten, Jacinta den; Jamieson, David N.; Ryan, Chris G.

1999-01-01

The lattice location of gold atoms in naturally occurring Au-doped pyrite crystals has been investigated with a nuclear microprobe using ion channeling. The specimens consisted of 300-μm diameter pyrite crystals in veins embedded in a quartz matrix from the Emperor mine in Fiji. The specimens were prepared by standard geological specimen preparation techniques and the pyrite crystals were analysed in situ in the quartz matrix. Significant trace elements in the crystals, determined by Proton Induced X-ray Emission with a 3 MeV H + microprobe, were Cu, As, Mo, Zn, Te, Au and Pb. The Au concentration was about 0.2 wt%. By the use of 2 MeV He + ion channeling, the Miller indices of the lowest order crystal axes nearest to the normal were determined from backscattering yield maps from two-dimensional angular scanning and comparison of the resulting patterns with published gnomonic projections. Channeling angular yield curves were obtained from Fe, S, As and Au signals. The results indicate that at least 35% of the Au is substituted onto lattice sites

A Simple Method for the Detection of Long-Chain Fatty Acids in an Anaerobic Digestate Using a Quartz Crystal Sensor

Directory of Open Access Journals (Sweden)

Takuro Kobayashi

2016-12-01

Full Text Available In anaerobic digestion (AD, long-chain fatty acids (LCFAs produced by hydrolysis of lipids, exhibit toxicity against microorganisms when their concentration exceeds several millimolar. An absorption detection system using a quartz crystal microbalance (QCM was developed to monitor the LCFA concentration during an anaerobic digester’s operation treating oily organic waste. The dissociation of the LCFAs considerably improved the sensor response and, moreover, enabled it to specifically detect LCFA from the mixture of LCFA and triglyceride. Under alkaline conditions, the frequency-shift rates of the QCM sensor linearly increased in accordance with palmitic acid concentration in the range of 0–100 mg/L. Frequency changes caused by anaerobic digestate samples were successfully measured after removing suspended solids and adjusting the pH to 10.7. Finally, the QCM measurements for digestate samples demonstrated that frequency-shift rates are highly correlated with LCFA concentrations, which confirmed that the newly developed QCM sensor is helpful for LCFA monitoring in terms of rapidness and usability.

The Shahewan rapakivi-textured granite – quartz monzonite pluton, Qinling orogen, central China: mineral composition and petrogenetic significance

Directory of Open Access Journals (Sweden)

Xiaoxia Wang

2002-01-01

Full Text Available The Mesozoic Shahewan pluton consists of four texturally different types of biotite-hornblende quartz monzonite. In the porphyritic types alkali feldspar occurs as euhedral or ovoidal megacrysts that are often mantled by one or more plagioclase shells, and as smaller grains in the groundmass. Quartz, plagioclase (An20–28, biotite, and hornblende occur as inclusions in the alkali feldspar megacrystsand, more abundantly, in the groundmass. Euhedral quartz crystals in the groundmass are not as common and well developed as in typical rapakivi granite. Compared to typical rapakivi granites, the mafic minerals (biotite and hornblende are rich in Mg and poor in Fe, and the whole rock is low in Si, K, F, Ga, Zr, LREE, Fe/Mg, and K/Na. The rocks of the Shahewan pluton are thus regarded as rapakivi-textured quartz monzonites and granites but not true rapakivi granites.

Electrochemical Properties for Co-Doped Pyrite with High Conductivity

Directory of Open Access Journals (Sweden)

Yongchao Liu

2015-09-01

Full Text Available In this paper, the hydrothermal method was adopted to synthesize nanostructure Co-doped pyrite (FeS2. The structural properties and morphology of the synthesized materials were characterized using X-ray diffraction (XRD and scanning electron microscopy (SEM, respectively. Co in the crystal lattice of FeS2 could change the growth rate of different crystal planes of the crystal particles, which resulted in various polyhedrons with clear faces and sharp outlines. In addition, the electrochemical performance of the doping pyrite in Li/FeS2 batteries was evaluated using the galvanostatic discharge test, cyclic voltammetry and electrochemical impedance spectroscopy. The results showed that the discharge capacity of the doped material (801.8 mAh·g−1 with a doping ratio of 7% was significantly higher than that of the original FeS2 (574.6 mAh·g−1 because of the enhanced conductivity. Therefore, the doping method is potentially effective for improving the electrochemical performance of FeS2.

Enhancement in photo-electrochemical efficiency by reducing recombination rate in branched TiO2 nanotube array on functionalizing with ZnO micro crystals

Science.gov (United States)

Boda, Muzaffar Ahmad; Ashraf Shah, Mohammad

2018-06-01

In this study, branched TiO2 nanotube array were fabricated through electrochemical anodization process at constant voltage using third generation electrolyte. On account of morphological advantage, these nanotubes shows significant enhancement in photo-electrochemical property than compact or conventional titania nanotube array. However, their photo-electrochemical efficiency intensifies on coating with ZnO micro-crystals. ZnO coated branched TiO2 nanotube array shows a photocurrent density of 27.8 mA cm‑2 which is 1.55 times the photocurrent density (17.2 mA cm‑2) shown by bare branched titania nanotubes. The significant enhancement in photocurrent density shown by the resulting ZnO/TiO2 hybrid structure is attributed to suppression in electron–hole recombination phenomenon by offering smooth pathway to photo generated excitons on account of staggered band edge positions in individual semiconductors.

Quartz fiber calorimeter

International Nuclear Information System (INIS)

Akchurin, N.; Doulas, S.; Ganel, O.; Gershtein, Y.; Gavrilov, V.; Kolosov, V.; Kuleshov, S.; Litvinsev, D.; Merlo, J.-P.; Onel, Y.; Osborne, D.; Rosowsky, A.; Stolin, V.; Sulak, L.; Sullivan, J.; Ulyanov, A.; Wigmans, R.; Winn, D.

1996-01-01

A calorimeter with optical quartz fibers embedded into an absorber matrix was proposed for the small angle region of the CMS detector at LHC (CERN). This type of calorimeter is expected to be radiation hard and to produce extremely fast signal. Some results from beam tests of the quartz fiber calorimeter prototype are presented. (orig.)

Electrochemically deposited sol-gel-derived silicate films as a viable alternative in thin-film design.

Science.gov (United States)

Deepa, P N; Kanungo, Mandakini; Claycomb, Greg; Sherwood, Peter M A; Collinson, Maryanne M

2003-10-15

Sol-gel-derived silicate films were electrochemically deposited on conducting surfaces from a sol consisting of tetramethoxysilane (TMOS). In this method, a sufficiently negative potential is applied to the electrode surface to reduce oxygen to hydroxyl ions, which serves as the catalyst for the hydrolysis and condensation of TMOS. The electrodeposition process was followed by the electrochemical quartz crystal microbalance and cyclic voltammetry. The electrodeposited films were characterized for their surface morphology, porosity, and film thickness using atomic force microscopy, electrochemical probe techniques, surface area and pore size analysis, and profilometry. The electrodeposited films were found to have a completely different surface structure and to be significantly rougher relative to spin-coated films. This is likely due in part to the separation of the gelation and evaporation stages of film formation. The electrodeposited films were found to be permeable to simple redox molecules, such as ruthenium(III) hexaammine and ferrocene methanol. Film thickness can be easily varied from 15 microm by varying the electrode potential from -600 mV to more than -1000 mV, respectively. The electrodeposition process was further applied for the electroencapsulation of redox molecules and organic dyes within the silicate network. Cyclic voltammograms for the gel-entrapped ferrocene methanol (FcCH2OH) and ruthenium(II) tris(bipyridine) (Ru(bpy)3(2+)) exhibited the characteristic redox behavior of the molecules. The electroencapsulation of organic dyes in their "native" form proved to be more difficult because these species typically contain reducible functionalities that change the structure of the dye.

Tin Oxide Crystals Exposed by Low-Energy {110} Facets for Enhanced Electrochemical Heavy Metal Ions Sensing: X-ray Absorption Fine Structure Experimental Combined with Density-Functional Theory Evidence.

Science.gov (United States)

Jin, Zhen; Yang, Meng; Chen, Shao-Hua; Liu, Jin-Huai; Li, Qun-Xiang; Huang, Xing-Jiu

2017-02-21

Herein, we revealed that the electrochemical behaviors on the detection of heavy metal ions (HMIs) would largely rely on the exposed facets of SnO 2 nanoparticles. Compared to the high-energy {221} facet, the low-energy {110} facet of SnO 2 possessed better electrochemical performance. The adsorption/desorption tests, density-functional theory (DFT) calculations, and X-ray absorption fine structure (XAFS) studies showed that the lower barrier energy of surface diffusion on {110} facet was critical for the superior electrochemical property, which was favorable for the ions diffusion on the electrode, and further leading the enhanced electrochemical performance. Through the combination of experiments and theoretical calculations, a reliable interpretation of the mechanism for electroanalysis of HMIs with nanomaterials exposed by different crystal facets has been provided. Furthermore, it provides a deep insight into understanding the key factor to improve the electrochemical performance for HMIs detection, so as to design high-performance electrochemical sensors.

A survey of the 2001 to 2005 quartz crystal microbalance biosensor literature: applications of acoustic physics to the analysis of biomolecular interactions.

Science.gov (United States)

Cooper, Matthew A; Singleton, Victoria T

2007-01-01

The widespread exploitation of biosensors in the analysis of molecular recognition has its origins in the mid-1990s following the release of commercial systems based on surface plasmon resonance (SPR). More recently, platforms based on piezoelectric acoustic sensors (principally 'bulk acoustic wave' (BAW), 'thickness shear mode' (TSM) sensors or 'quartz crystal microbalances' (QCM)), have been released that are driving the publication of a large number of papers analysing binding specificities, affinities, kinetics and conformational changes associated with a molecular recognition event. This article highlights salient theoretical and practical aspects of the technologies that underpin acoustic analysis, then reviews exemplary papers in key application areas involving small molecular weight ligands, carbohydrates, proteins, nucleic acids, viruses, bacteria, cells and lipidic and polymeric interfaces. Key differentiators between optical and acoustic sensing modalities are also reviewed. Copyright (c) 2007 John Wiley & Sons, Ltd.

Development of a Quartz Crystal Microbalance Sensor Modified by Nano-Structured Polyaniline for Detecting the Plasticizer in Gaseous State

Directory of Open Access Journals (Sweden)

Hui XU

2014-01-01

Full Text Available A quartz crystal microbalance (QCM modified by a film of nano-structured polyaniline (nano-PANI is developed as a gas sensor for detecting the presence of the plasticizer, such as dibutyl phthalate (DBP in the ambient. Nano-PANI is prepared using a non-template method and the films are deposited using physical coating method. Scanning electron microscopy is used to characterize the nano-PANI film. The sensor response towards DBP is tested in a sealed gas chamber. The QCM resonant frequency shift is measured due to the absorption of DBP with different concentration ranging from 0.04 to 1.2 ppm. The experiment results show that the variation of the frequency is a linear function of DBP concentration and the sensitivity up to 54 Hz/ppm could be achieved by using the researched nano-PANI on QCM. To investigate the selectivity, the potential interfering analytes such as acetone, ethanol, acetaldehyde and formaldehyde are tested. And the mechanism hypothesis of the nano-PANI sensitive to the plasticizer is analyzed.

An in-situ X-ray diffraction study on the electrochemical formation of PtZn alloys on Pt(1 1 1) single crystal electrode

Energy Technology Data Exchange (ETDEWEB)

Drnec, J., E-mail: drnec@esrf.fr [ESRF, Grenoble (France); Bizzotto, D. [Department of Chemistry, AMPEL, University of British Columbia, Vancouver, BC (Canada); Carlà, F. [ESRF, Grenoble (France); Fiala, R. [Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Sode, A. [Ruhr-Universität Bochum, Bochum (Germany); Balmes, O.; Detlefs, B.; Dufrane, T. [ESRF, Grenoble (France); Felici, R., E-mail: felici@esrf.fr [ESRF, Grenoble (France)

2015-11-01

Highlights: • PtZn electrochemical alloying is observed on single crystal Pt electrodes. • In-situ X-ray characterization during alloy formation and dissolution is provided. • Structural model of the surface during alloying and dissolution is discussed. • X-ray based techniques can be used in in-operando studies of bimetallic fuel cell catalysts. - Abstract: The electrochemical formation and dissolution of the oxygen reduction reaction (ORR) PtZn catalyst on Pt(1 1 1) surface is followed by in-situ X-ray diffraction (XRD) and X-ray reflectivity (XRR) measurements. When the crystalline Pt surface is polarized to sufficiently negative potential values, with respect to an Ag/AgCl|KCl reference electrode, the electrodeposited zinc atoms diffuse into the bulk and characteristic features are observed in the X-ray patterns. The surface structure and composition during deposition and dissolution is determined from analysis of XRR curves and measurements of crystal truncation rods. Thin Zn-rich surface layer is present during the alloy formation while a Zn-depleted layer forms during dissolution.

Quasi 2D Mesoporous Carbon Microbelts Derived from Fullerene Crystals as an Electrode Material for Electrochemical Supercapacitors.

Science.gov (United States)

Tang, Qin; Bairi, Partha; Shrestha, Rekha Goswami; Hill, Jonathan P; Ariga, Katsuhiko; Zeng, Haibo; Ji, Qingmin; Shrestha, Lok Kumar

2017-12-27

Fullerene C 60 microbelts were fabricated using the liquid-liquid interfacial precipitation method and converted into quasi 2D mesoporous carbon microbelts by heat treatment at elevated temperatures of 900 and 2000 °C. The carbon microbelts obtained by heat treatment of fullerene C 60 microbelts at 900 °C showed excellent electrochemical supercapacitive performance, exhibiting high specific capacitances ca. 360 F g -1 (at 5 mV s -1 ) and 290 F g -1 (at 1 A g -1 ) because of the enhanced surface area and the robust mesoporous framework structure. Additionally, the heat-treated carbon microbelt showed good rate performance, retaining 49% of capacitance at a high scan rate of 10 A g -1 . The carbon belts exhibit super cyclic stability. Capacity loss was not observed even after 10 000 charge/discharge cycles. These results demonstrate that the quasi 2D mesoporous carbon microbelts derived from a π-electron-rich carbon source, fullerene C 60 crystals, could be used as a new candidate material for electrochemical supercapacitor applications.

Development of early diagenetic silica and quartz morphologies — Examples from the Siri Canyon, Danish North Sea

DEFF Research Database (Denmark)

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

2010-01-01

in the following way: 1. Opal rims; characteristic of the initial phase of the silica diagenesis in most sandstone units in the Siri Canyon. Thick opal rims characterise the sandstone parts adjacent to the mudstone units in the Stine segment of the Siri Field. 2. Microquartz (quartz crystals with a size of 1–5 μm......); seen as coatings on the opal rims, both ordered and random. 3. Cavity overgrowth; found as quartz outgrowths in circular and angular cavities formed by dissolution of early authigenic phases. Angular cavities in the microquartz coatings origin from dissolution of clinoptilolite, possibly with a source...

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)

Comparative study of the thermoluminescence properties of natural metamorphic quartz belonging to Turkey and Spain

International Nuclear Information System (INIS)

Topaksu, M.; Dogan, T.; Yüksel, M.; Kurt, K.; Topak, Y.; Yegingil, Z.

2014-01-01

The aim of this study is to investigate the sensitization of the thermoluminescence (TL) peak of metamorphic quartzes from Adiyaman in Turkey (TMQ) and from Madrid in Spain (SMQ). Quartz samples of two different origins were β-irradiated between ∼6.689 Gy and 4816 Gy at room temperature. X-ray diffraction analysis has indicated that both TMQ and SMQ have the same crystal structure. Chemical analyses of both TMQ and SMQ were performed using the XRF technique. The preheat processes were carried out at 125 °C for 10 s in the TL measurement. TMQ and SMQ samples have different TL properties in two ways. First TMQ has four first order TL glow peaks while SMQ has five first order TL peaks and secondly, the observed dose sensitivity of TMQ samples is higher than the SMQ samples. - Highlights: • The thermoluminescence (TL) peak of metamorphic quartzes was investigated. • Comparable differences were seen between low and high dose levels. • AD and CGCD methods were used

Pentanol as Co-Surfactant in Polypyrrole Actuators

DEFF Research Database (Denmark)

Bay, Lasse; West, Keld; Skaarup, Steen

2002-01-01

of the film is changed considerable upon pentanol addition, although electrochemical quartz crystal microbalance measurements indicate that pentanol is only incorporated in the polymer to a small extent. The mechanical properties, conductivity and doping level of PPy-DBS films show little or no changes...

The problem of dating quartz 2: Synchrotron generated X-ray excited optical luminescence (XEOL) from quartz

International Nuclear Information System (INIS)

King, G.E.; Finch, A.A.; Robinson, R.A.J.; Taylor, R.P.; Mosselmans, J.F.W.

2011-01-01

The luminescence emission of quartz is used in optically stimulated luminescence dating (OSL), however the precise origins of the emission are unclear. A suite of quartz samples were analysed using X-ray excited optical luminescence (XEOL). Radiation dose effects were observed whereby the UV emissions (3.8 and 3.4 eV) were depleted to the benefit of the red emission (1.9-2.0 eV). Samples were excited at ∼7 keV. Understanding why some quartz emit light more brightly than others will increase the efficiency and precision of OSL analyses. - Highlights: → The X-ray excited optical luminescence (XEOL) emission of quartz is explored. → The XEOL of quartz of different provenances varies. → Radiation dosing causes UV emissions to deplete to the benefit of red emissions. → The 3.8 and 3.4 eV emissions deplete at the same rate. → The quartz luminescence emission exhibits anisotropic effects.

Quartz analysis in gravimetric sampling

International Nuclear Information System (INIS)

Rex, D.A.

1990-01-01

An overview of the methods employed in the assessment of quartz exposure is provided. The principles and some of the problems associated with each method is discussed. The methods reviewed include wet chemical methods, X-ray diffraction and infrared absorption of which the latter two methods are deemed appropriate for analysing quartz on personal gravimetric collected samples. The implications of combining area samples collected over a six month period, and performing only a single quartz analysis rather than separate analyses, are considered. Finally, various options open to mines with regard to their involvement with quartz analysis are also briefly discussed. 35 refs., 6 figs., 1 tab

Production of mineral aggregates in quartz tumbling experiments

Science.gov (United States)

Nørnberg, Per; Finster, Kai; Pall Gunnlaugsson, Haraldur; Knak Jensen, Svend; Merrison, Jonathan Peter

2013-04-01

Introduction Tumbling experiments with quartz sand with the purpose of tracing the effect of broken bonds in mineral surfaces resulted in an unexpected production of aggregates. These aggregates are a few microns in diameter, spherical and resembling tiny white "snowballs." Particle comminution by aeolian and other natural weathering processes are known in soil science and is often seen as an increase of fine particles towards the top of soil profiles (Nørnberg, P. 1987, 1988, 2002, J.S. Wright 2007). When mineral grains collide in aeolian processes they break up along weakness zones in the crystal lattice. This mechanism causes broken bonds between atoms in the crystal lattice and results in reactive groups in the mineral surface. This mechanism provides the background for experiments to investigate the oxidation processes of magnetite on the planet Mars. The primary magnetic iron oxide phase on Mars is to day known to be magnetite and the colour of the dust on Mars is most likely due to hematite. To investigate if the oxidation process could take place without going over dissolution and precipitation in water, experiments with tumbling of quartz grains in sealed glass containers along with magnetite were started. The idea was that activated bonds at the surface of quartz could oxidize magnetite and convert it to hematite over time. This proved to be the case (Merrison, J.P. et al. 2010). However, in these experiments we observed the formation of the white aggregates which has been the subject of the study that we present here. Results of tumbling experiments Commercially available quarts (Merck) was sieved to obtain the fraction between 125 and 1000 µm. This fraction was tumbled in glass containers for months and resulted in production of a significant amount of fine grained material (Merrison, J.P et al. 2010). A part of this fine fraction consists of the "snowball"-like aggregates which is a fragile element with relatively high specific surface. The physical

Radiation-Hard Quartz Cerenkov Calorimeters

International Nuclear Information System (INIS)

Akgun, U.; Onel, Y.

2006-01-01

New generation hadron colliders are going to reach unprecedented energies and radiation levels. Quartz has been identified as a radiation-hard material that can be used for Cerenkov calorimeters of the future experiments. We report from the radiation hardness tests performed on quartz fibers, as well as the characteristics of the quartz fiber and plate Cerenkov calorimeters that have been built, designed, and proposed for the CMS experiment

Fluid Inclusion Study of Quartz Xenocrysts in Mafic Dykes from Kawant Area, Chhota Udaipur District, Gujarat, India

Directory of Open Access Journals (Sweden)

Randive Kirtikumar

2015-09-01

Full Text Available Unusual mafic dykes occur in the proximity of the Ambadongar Carbonatite Complex, Lower Narmada Valley, Gujarat, India. The dykes contain dense population of quartz xenocrysts within the basaltic matrix metasomatised by carbonate-rich fluids. Plagioclase feldspars, relict pyroxenes, chlorite, barite, rutile, magnetite, Fe-Ti oxides and glass were identified in the basaltic matrix. Quartz xenocrysts occur in various shapes and sizes and form an intricate growth pattern with carbonates. The xenocrysts are fractured and contain several types of primary and secondary, single phase and two-phase fluid inclusions. The two-phase inclusions are dominated by aqueous liquid, whereas the monophase inclusions are composed of carbonic gas and the aqueous inclusions homogenize to liquid between 226°C and 361°C. Majority of the inclusions are secondary in origin and are therefore unrelated to the crystallization of quartz. Moreover, the inclusions have mixed carbonic-aqueous compositions that inhibit their direct correlation with the crustal or mantle fluids. The composition of dilute CO2-rich fluids observed in the quartz xenocrysts appear similar to those exsolved during the final stages of evolution of the Amba Dongar carbonatites. However, the carbonates are devoid of fluid inclusions and therefore their genetic relation with the quartz xenocrysts cannot be established.

Electrochemically modified crystal orientation, surface morphology and optical properties using CTAB on Cu2O thin films

Directory of Open Access Journals (Sweden)

Karupanan Periyanan Ganesan

Full Text Available Cuprous oxide (Cu2O thin films with different crystal orientations were electrochemically deposited in the presence of various molar concentrations of cetyl trimethyl ammonium bromide (CTAB on fluorine doped tin oxide (FTO glass substrate using standard three electrodes system. X-ray diffraction (XRD studies reveal cubic structure of Cu2O with (111 plane orientation, after addition of CTAB in deposition solution, the orientation of crystal changes from (111 into (200 plane. Scanning electron microscope (SEM images explored significant variation on morphology of Cu2O thin films deposited with addition of CTAB compared to without addition of CTAB. Photoluminescence (PL spectra illustrate that the emission peak around at 650 nm is attributed to near band edge emission, and the film prepared at the 3 mM of CTAB exhibits much higher intensity than that of the all other films. UV–Visible spectra show optical absorption in the range of 480–610 nm and the highest transparency of Cu2O film prepared at the concentration of 3 mM CTAB. The optical band gap is increased in the range between 2.16 and 2.45 eV with increasing the CTAB concentrations. Keywords: Cuprous oxide, Crystal orientation, Electrodeposition and cubic structure

Electrochemical sensing of 2D condensation in amyloid peptides

Czech Academy of Sciences Publication Activity Database

Kurzatkowska, K.; Ostatná, Veronika; Hamley, I.W.; Doneux, T.; Paleček, Emil

2013-01-01

Roč. 106, SEP2013 (2013), s. 43-48 ISSN 0013-4686 R&D Projects: GA ČR(CZ) GAP301/11/2055 Institutional support: RVO:68081707 Keywords : QUARTZ-CRYSTAL-MICROBALANCE * SELF -ASSEMBLED MONOLAYERS * BETA-SHEET PEPTIDES Subject RIV: BO - Biophysics Impact factor: 4.086, year: 2013

Carbon-Ring Microelectrode Arrays for Electrochemical Imaging of Single Cell Exocytosis: Fabrication and Characterization

Science.gov (United States)

Lin, Yuqing; Trouillon, Raphaël; Svensson, Maria I.; Keighron, Jacqueline D.; Cans, Ann-Sofie; Ewing, Andrew G.

2012-01-01

Fabrication of carbon microelectrode arrays, with up to 15 electrodes in total tips as small as 10 to 50 μm, is presented. The support structures of microelectrodes were obtained by pulling multiple quartz capillaries together to form hollow capillary arrays before carbon deposition. Carbon ring microelectrodes were deposited by pyrolysis of acetylene in the lumen of these quartz capillary arrays. Each carbon deposited array tip was filled with epoxy, followed by beveling of the tip of the array to form a deposited carbon-ring microelectrode array (CRMA). Both the number of the microelectrodes in the array and the tip size are independently tunable. These CRMAs have been characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, and electrogenerated chemiluminescence. Additionally, the electrochemical properties were investigated with steady-state voltammetry. In order to demonstrate the utility of these fabricated microelectrodes in neurochemistry, CRMAs containing eight microring electrodes were used for electrochemical monitoring of exocytotic events from single PC12 cells. Subcellular temporal heterogeneities in exocytosis (ie. cold spots vs. hot spots) were successfully detected with the CRMAs. PMID:22339586

Opalescence of quartz: a study by high energy x-ray diffraction

Science.gov (United States)

Bastie, P.; Dolino, G.; Hamelin, B.

2003-05-01

The origin of the opalescence observed at the α-β transition of quartz remains an open question. This intense light scattering occurs during the coexistence, at the first order transition, of the α and incommensurate (inc) phases, in the vicinity of the phase interface. New hard x-ray diffraction experiment shows that the large angle light scattering is mainly in the α-phase region of the crystal and reveals the existence of an intermediate structure between the α-phase and the 3q inc phase.

Opalescence of quartz: a study by high energy x-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Bastie, P [Laboratoire de Spectrometrie Physique, Universite Joseph Fourier-Grenoble 1 - CNRS, UMR No 5588, BP 87, 38402 Saint Martin d' Heres Cedex (France); Dolino, G [Laboratoire de Spectrometrie Physique, Universite Joseph Fourier-Grenoble 1 - CNRS, UMR No 5588, BP 87, 38402 Saint Martin d' Heres Cedex (France); Hamelin, B [Institut Laue Langevin, BP 156X, 38042 Grenoble Cedex 9 (France)

2003-05-21

The origin of the opalescence observed at the {alpha}-{beta} transition of quartz remains an open question. This intense light scattering occurs during the coexistence, at the first order transition, of the {alpha} and incommensurate (inc) phases, in the vicinity of the phase interface. New hard x-ray diffraction experiment shows that the large angle light scattering is mainly in the {alpha}-phase region of the crystal and reveals the existence of an intermediate structure between the {alpha}-phase and the 3q inc phase.

Study of green quartz of hydrothermal origin treated by gamma radiation; Estudo do quartzo verde de origem hidrotermal tratado com radiacao gama

Energy Technology Data Exchange (ETDEWEB)

Enokihara, Cyro Teiti

2013-07-01

A specific variety of quartz showing a green color in nature or induced artificially by radiation is quite rare. This can be explained by the fact that the mechanism of formation of this color is very different from the ones widely discussed in the literature and responsible for the formation of the fumee, citrine and amethyst types of quartz, including the prasiolite (leak green quartz) formed by heating amethyst from Montezuma, Brazil. Only two occurrences are known today, where this type of quartz can be found: Canada, at the Thunder Bay Amethyst Mine, Ontario, a small district, and Brazil, at widely scattered geode occurrences along a 600 km stretch from Quarai at Brazils southernmost tip to Uberlandia in Minas Gerais. These two occurrences have been formed by strong hydrothermal activities, at Thunder Bay due to tectonics and in Brazil by meteoric and hydrothermal waters of the Guarani aquifer. 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. This type of quartz can be considered 'wet quartz', similar to synthetic quartz. 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. Instead, silanol complexes are formed, which by radiation due to gamma rays form the color center NBOHC (non-bonding oxygen hole defect), showing absorption between 590 to 620 nm and leaving a transmission window at about 550nm, responsible for the green color. To characterize samples which will be colored green by gamma rays analyses by ICP, NAA, Electron microscopy, water loss techniques and UV-VIS and NIR-FTIR spectroscopic have been made. The spectroscopic water determination showed less water (up to 2300 ppm by weight

Significance of Dauphiné twins in crystallographic fabrics of quartz tectonites

Science.gov (United States)

Eske Sørensen, Bjørn

2014-05-01

Dauphine twins are commonly found in quartz tectonites, however their role in deformation processes are not completely understood. This study represents a new attempt to understand the interaction between slip systems and Dauphine twins in deforming quartz-rich rocks at different temperatures. There is no doubt that Dauphine twins are mobilized under stress as this has been shown by experiments for single crystals and in polycrystalline aggregates where distinct crystallographic fabrics develop in previously randomly oriented aggregates related to minimization of elastic energy (Tullis 1972). However in quartz tectonites the Dauphine twin process is a part of interplay between plastic deformation and recovery processes which depends on PT, strain-rate and fluid composition and availability. In quartz tectonites with Y-girdle C-axis (GBM-regime) fabrics Dauphiné twins are abundant, relating different parts of r- and z rhomb "comet" distributions. This is interpreted as completion between prism slip and Dauphiné twinning. Slip rotates grains such that CRSS is low on the prism planes, but then Dauphiné twin boundaries sweeps through the grain back to the orientation giving lower stored elastic energy. The faster recovery at higher temperatures gives subgrain walls slowing down twin movement across the mm-sized grain of the GBM regime. At lower temperatures in the SGR-regime grain-size is reduced and different rotations of the grains are happening due to the domination of rhomb and basal slip. Because recrystallization is effective relative to grain-size the grains are commonly free of internal strain and subgrain walls, allowing the favorably oriented Dauphiné twin member to sweep across the whole grain overwhelming the unfavorably oriented Dauphiné twin member. As a consequence high strain reduces the number of Dauphiné twins and quartz rhomb fabrics appear trigonal, missing the "comet" shape of the GBM regime rhomb fabrics. Since Dauphiné twinning is also

Electrochemically induced co-crystallization for product removal

NARCIS (Netherlands)

Urbanus, J.; Roelands, C.P.M.; Mazurek, J.; Verdoes, D.; Horst, J.H. ter

2011-01-01

We demonstrate the potential of co-crystallization combined with electrochemistry for in situ product removal of carboxylic acids. Proof-of-principle is established using a cinnamic acid:3-nitrobenzamide (HCA:NBA) co-crystal system. This technology can be applied in the bio-based production of

Kinetic model for quartz and spinel dissolution during melting of high-level-waste glass batch

International Nuclear Information System (INIS)

Pokorny, Richard; Rice, Jarrett A.; Crum, Jarrod V.; Schweiger, Michael J.; Hrma, Pavel

2013-01-01

The dissolution of quartz particles and the growth and dissolution of crystalline phases during the conversion of batch to glass potentially affects both the glass melting process and product quality. Crystals of spinel exiting the cold cap to molten glass below can be troublesome during the vitrification of iron-containing high-level wastes. To estimate the distribution of quartz and spinel fractions within the cold cap, we used kinetic models that relate fractions of these phases to temperature and heating rate. Fitting the model equations to data showed that the heating rate, apart from affecting quartz and spinel behavior directly, also affects them indirectly via concurrent processes, such as the formation and motion of bubbles. Because of these indirect effects, it was necessary to allow one kinetic parameter (the pre-exponential factor) to vary with the heating rate. The resulting kinetic equations are sufficiently simple for the detailed modeling of batch-to-glass conversion as it occurs in glass melters. The estimated fractions and sizes of quartz and spinel particles as they leave the cold cap, determined in this study, will provide the source terms needed for modeling the behavior of these solid particles within the flow of molten glass in the melter

New contribution in the study of phase formation in mixed alkanethiol self-assembled monolayers: a powerful tool for transducers design

International Nuclear Information System (INIS)

Coelho, Dyovani; Machado, Sergio A.S.

2014-01-01

Here, the formation of distinct 3-mercaptopropionic acid (MPA) and 11-mercaptoundecanoic acid (MUA) domains on polycrystalline gold surfaces was investigated by cyclic voltammetry and electrochemical quartz crystal nanobalance. Voltammetric experiments with the [Fe(CN) 6 ] 4-/3− redox couple showed that the MPA SAM allowed electron transference at the same rate as the bare gold surface, while the MUA SAM blocked the entire electrode surface. The chemical nature of mixed SAMs is discussed by evaluating the mass variations and the respective molecular weight in the desorption potential regions for each thiol by electrochemical quartz crystal nanobalance. Different domains containing MUA, MPA and their mixtures were identified in the massograms, thus demonstrating MPA island domains and the electrochemical response obtained for the [Fe(CN) 6 ] 4-/3− redox couple. The modified surfaces, as well as bare Au electrode, were used for electroanalysis of the flavonoid fisetin in Britton-Robinson buffer solution, pH 5. Depending on the modification, detection limits as low as 3.35 ×10 −10 mol L −1 , which attests the possibility of use such surfaces in electroanalysis

Adsorption Analysis of Lactoferrin to Titanium, Stainless Steel, Zirconia, and Polymethyl Methacrylate Using the Quartz Crystal Microbalance Method

Directory of Open Access Journals (Sweden)

Eiji Yoshida

2016-01-01

Full Text Available It is postulated that biofilm formation in the oral cavity causes some oral diseases. Lactoferrin is an antibacterial protein in saliva and an important defense factor against biofilm development. We analyzed the adsorbed amount of lactoferrin and the dissociation constant (Kd of lactoferrin to the surface of different dental materials using an equilibrium analysis technique in a 27 MHz quartz crystal microbalance (QCM measurement. Four different materials, titanium (Ti, stainless steel (SUS, zirconia (ZrO2 and polymethyl methacrylate (PMMA, were evaluated. These materials were coated onto QCM sensors and the surfaces characterized by atomic force microscopic observation, measurements of surface roughness, contact angles of water, and zeta potential. QCM measurements revealed that Ti and SUS showed a greater amount of lactoferrin adsorption than ZrO2 and PMMA. Surface roughness and zeta potential influenced the lactoferrin adsorption. On the contrary, the Kd value analysis indicated that the adsorbed lactoferrin bound less tightly to the Ti and SUS surfaces than to the ZrO2 and PMMA surfaces. The hydrophobic interaction between lactoferrin and ZrO2 and PMMA is presumed to participate in better binding of lactoferrin to ZrO2 and PMMA surfaces. It was revealed that lactoferrin adsorption behavior was influenced by the characteristics of the material surface.

Determination of functionalized gold nanoparticles incorporated in hydrophilic and hydrophobic microenvironments by surface modification of quartz crystal microbalance

Energy Technology Data Exchange (ETDEWEB)

Wu, Tsui-Hsun [Institute of Biomedical Engineering, College of Engineering, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC (China); Institute of Medical Mechatronics, Chang Gung University, Tao-Yuan, Taiwan, ROC (China); Liao, Shu-Chuan [Center of Thin Film Technologies and Applications, Mingchi University of Technology, Taipei, Taiwan, ROC (China); Chen, Ying-Fang [Department of Dentistry, Yun-Lin Branch, National Taiwan University Hospital, Dou-Liu, Yun-Lin, Taiwan, ROC (China); Huang, Yi-You [Institute of Biomedical Engineering, College of Engineering, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC (China); Wei, Yi-Syuan [Department of Materials Engineering, Tatung University, 40 Zhongshan North Road, 3rd Section, Taipei 104, Taiwan, ROC (China); Tu, Shu-Ju, E-mail: sjt@cgu.edu.tw [Department of Medical Imaging and Radiological Sciences, Chang Gung University, 259 Wen-Hwa, 1st Road, Kwei-Shan, Tao-Yuan 133, Taiwan, ROC (China); Chen, Ko-Shao, E-mail: kschen@ttu.edu.tw [Department of Materials Engineering, Tatung University, 40 Zhongshan North Road, 3rd Section, Taipei 104, Taiwan, ROC (China)

2013-06-01

In this study, plasma deposition methods were used to immobilize Au electrode of a quartz crystal microbalance (QCM) to create different microenvironments for mass measurement of various modified Au nanoparticles (AuNPs). AuNPs were modified by 11-mercaptoundecanoic acid (MUA) and 1-decanethiol (DCT) for potential applications to drug release, protective coatings, and immunosensors. We aimed to develop a highly sensitive and reliable method to quantify the mass of various modified AuNPs. The surface of AuNPs and Au electrode was coated with polymer films, as determined by Fourier transform infrared spectroscopy and atomic force microscopy. Measurements obtained for various AuNPs and the plasma-treated surface of the Au electrode were compared with those obtained for an untreated Au electrode. According to the resonant frequency shift of QCM, a linear relationship was observed that significantly differed for AuNPs, MUA-AuNPs, and DCT-AuNPs (R{sup 2} range, 0.94–0.965, 0.934–0.972, and 0.874–0.9514, respectively). Compared to inductively coupled plasma and micro-computerized tomography, the QCM method with plasma treatment has advantages of real-time monitoring, greater sensitivity, and lower cost. Our results demonstrate that surface modifications measured by a QCM system for various modified AuNPs were reliable.

Determination of functionalized gold nanoparticles incorporated in hydrophilic and hydrophobic microenvironments by surface modification of quartz crystal microbalance

International Nuclear Information System (INIS)

Wu, Tsui-Hsun; Liao, Shu-Chuan; Chen, Ying-Fang; Huang, Yi-You; Wei, Yi-Syuan; Tu, Shu-Ju; Chen, Ko-Shao

2013-01-01

In this study, plasma deposition methods were used to immobilize Au electrode of a quartz crystal microbalance (QCM) to create different microenvironments for mass measurement of various modified Au nanoparticles (AuNPs). AuNPs were modified by 11-mercaptoundecanoic acid (MUA) and 1-decanethiol (DCT) for potential applications to drug release, protective coatings, and immunosensors. We aimed to develop a highly sensitive and reliable method to quantify the mass of various modified AuNPs. The surface of AuNPs and Au electrode was coated with polymer films, as determined by Fourier transform infrared spectroscopy and atomic force microscopy. Measurements obtained for various AuNPs and the plasma-treated surface of the Au electrode were compared with those obtained for an untreated Au electrode. According to the resonant frequency shift of QCM, a linear relationship was observed that significantly differed for AuNPs, MUA-AuNPs, and DCT-AuNPs (R 2 range, 0.94–0.965, 0.934–0.972, and 0.874–0.9514, respectively). Compared to inductively coupled plasma and micro-computerized tomography, the QCM method with plasma treatment has advantages of real-time monitoring, greater sensitivity, and lower cost. Our results demonstrate that surface modifications measured by a QCM system for various modified AuNPs were reliable.

Determination of functionalized gold nanoparticles incorporated in hydrophilic and hydrophobic microenvironments by surface modification of quartz crystal microbalance

Science.gov (United States)

Wu, Tsui-Hsun; Liao, Shu-Chuan; Chen, Ying-Fang; Huang, Yi-You; Wei, Yi-Syuan; Tu, Shu-Ju; Chen, Ko-Shao

2013-06-01

In this study, plasma deposition methods were used to immobilize Au electrode of a quartz crystal microbalance (QCM) to create different microenvironments for mass measurement of various modified Au nanoparticles (AuNPs). AuNPs were modified by 11-mercaptoundecanoic acid (MUA) and 1-decanethiol (DCT) for potential applications to drug release, protective coatings, and immunosensors. We aimed to develop a highly sensitive and reliable method to quantify the mass of various modified AuNPs. The surface of AuNPs and Au electrode was coated with polymer films, as determined by Fourier transform infrared spectroscopy and atomic force microscopy. Measurements obtained for various AuNPs and the plasma-treated surface of the Au electrode were compared with those obtained for an untreated Au electrode. According to the resonant frequency shift of QCM, a linear relationship was observed that significantly differed for AuNPs, MUA-AuNPs, and DCT-AuNPs (R2 range, 0.94-0.965, 0.934-0.972, and 0.874-0.9514, respectively). Compared to inductively coupled plasma and micro-computerized tomography, the QCM method with plasma treatment has advantages of real-time monitoring, greater sensitivity, and lower cost. Our results demonstrate that surface modifications measured by a QCM system for various modified AuNPs were reliable.

Optical Effects Accompanying the Dynamical Bragg Diffraction in Linear 1D Photonic Crystals Based on Porous Silicon

Directory of Open Access Journals (Sweden)

Anton Maydykovskiy

2014-10-01

Full Text Available We survey our recent results on the observation and studies of the effects accompanying the dynamical Bragg diffraction in one-dimensional photonic crystals (PhC. Contrary to the kinematic Bragg diffraction, the dynamical one considers a continuous interaction between the waves travelling within a spatially-periodic structure and is the most pronounced in the so called Laue geometry, leading to a number of exciting phenomena. In the described experiments, we study the PhC based on porous silicon or porous quartz, made by the electrochemical etching of crystalline silicon with the consequent thermal annealing. Importantly, these PhC are approximately hundreds of microns thick and contain a few hundreds of periods, so that the experiments in the Laue diffraction scheme are available. We discuss the effect of the temporal splitting of femtosecond laser pulses and show that the effect is quite sensitive to the polarization and the phase of a femtosecond laser pulse. We also show the experimental realization of the Pendular effect in porous quartz PhC and demonstrate the experimental conditions for the total spatial switching of the output radiation between the transmitted and diffracted directions. All described effects are of high interest for the control over the light propagation based on PhC structures.

Quartz glass behavior at ultraviolet spectrum region

International Nuclear Information System (INIS)

Braga, A.F.B.; Barbosa, L.C.; Evora, C.A.P.D.

1990-01-01

Melted quartz ingots were produced from raw materials of different sources. Behavior studies of these three different quartz glass were made at the eletromagnetic spectrum ultraviolet region. The atomic absorption spectroscopy was used as an analysis technique of the alkaline, transition and aluminum metal traces. It was found that the alkaline, transition and aluminum metals impurities present a great influence on the melted quartz spectral behavior at the ultraviolet region. It was stated that measurments at this spectrum region constitute an important characterization technique to natural quartz as well as melted quartz. (author) [pt

1-Butyl-3-Methylimidazolium Tetrafluoroborate Film as a Highly Selective Sensing Material for Non-Invasive Detection of Acetone Using a Quartz Crystal Microbalance.

Science.gov (United States)

Tao, Wenyan; Lin, Peng; Liu, Sili; Xie, Qingji; Ke, Shanming; Zeng, Xierong

2017-01-20

Breath acetone serves as a biomarker for diabetes. This article reports 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF₄]), a type of room temperature ionic liquid (RTIL), as a selective sensing material for acetone. The RTIL sensing layer was coated on a quartz crystal microbalance (QCM) for detection. The sensing mechanism is based on a decrease in viscosity and density of the [bmim][BF₄] film due to the solubilization of acetone leading to a positive frequency shift in the QCM. Acetone was detected with a linear range from 7.05 to 750 ppmv. Sensitivity and limit of detection were found to be 3.49 Hz/ppmv and 5.0 ppmv, respectively. The [bmim][BF₄]-modified QCM sensor demonstrated anti-interference ability to commonly found volatile organic compounds in breath, e.g., isoprene, 1,2-pentadiene, d -limonene, and dl -limonene. This technology is useful for applications in non-invasive early diabetic diagnosis.

Stresses and pressures at the quartz-coesite transition in shear experiments

Science.gov (United States)

Richter, B.; Stunitz, H.; Heilbronner, R.

2015-12-01

Experiments on quartz (qtz) gouge were performed in a Griggs-type deformation apparatus at displacement rates of ~1.3 x 10-5 mms-1 or ~1.3 x 10-4 mms-1, at Pc= 1.0 GPa or 1.5 GPa and T = 600°C to 800°C. The starting material is a natural hydrothermally grown single crystal that was crushed to a powder with grain size d reaction from coe to qtz is observed. It appears therefore that the pressure that defines the QCT is not Pc or Pm, but σ1.

Anodic processes in the chemical and electrochemical etching of Si crystals in acid-fluoride solutions: Pore formation mechanism

Energy Technology Data Exchange (ETDEWEB)

Ulin, V. P.; Ulin, N. V.; Soldatenkov, F. Yu., E-mail: f.soldatenkov@mail.ioffe.ru [Ioffe Physical–Technical Institute (Russian Federation)

2017-04-15

The interaction of heavily doped p- and n-type Si crystals with hydrofluoric acid in the dark with and without contact with metals having greatly differing work functions (Ag and Pd) is studied. The dependences of the dissolution rates of Si crystals in HF solutions that contain oxidizing agents with different redox potentials (FeCl{sub 3}, V{sub 2}O{sub 5} and CrO{sub 3}) on the type and level of silicon doping are determined. Analysis of the experimental data suggests that valence-band holes in silicon are not directly involved in the anodic reactions of silicon oxidation and dissolution and their generation in crystals does not limit the rate of these processes. It is also shown that the character and rate of the chemical process leading to silicon dissolution in HF-containing electrolytes are determined by the interfacial potential attained at the semiconductor–electrolyte interface. The mechanism of electrochemical pore formation in silicon crystals is discussed in terms of selfconsistent cooperative reactions of nucleophilic substitution between chemisorbed fluorine anions and coordination- saturated silicon atoms in the crystal subsurface layer. A specific feature of these reactions for silicon crystals is that vacant nonbonding d{sup 2}sp{sup 3} orbitals of Si atoms, associated with sixfold degenerate states corresponding to the Δ valley of the conduction band, are involved in the formation of intermediate complexes. According to the suggested model, the pore-formation process spontaneously develops in local regions of the interface under the action of the interfacial potential in the adsorption layer and occurs as a result of the detachment of (SiF{sub 2}){sub n} polymer chains from the crystal. Just this process leads to the preferential propagation of pores along the <100> crystallographic directions. The thermodynamic aspects of pore nucleation and the effect of the potential drop across the interface, conduction type, and free-carrier concentration

Experimental diagenesis of quartz with petroleum; Diagenese experimentale du quartz en presence d'hydrocarbures

Energy Technology Data Exchange (ETDEWEB)

Teinturier, St.

2002-11-01

Quartz cementation has a great impact on petroleum reservoir quality by controlling the porosity and thus the gas or oil storage. However, the possible cementation of quartz during petroleum emplacement is still debated. In most cases, the reconstitution and the understanding of diagenetic processes is based on fluid inclusions studies. However, many questions concerning the representativeness and the reading of the fluid inclusions still remains misunderstood. The experiments were carried out in a silica{+-}water{+-}salts{+-}oil{+-}gas system with the objective to simulate the siliceous diagenesis of natural petroleum reservoirs and to better understand the mechanisms of fluid inclusions formation and quartz cementation in a water and/or petroleum system. Calibration curves have been established using Raman micro-spectroscopy and synthetic reference inclusions to calculate the methane content of aqueous inclusions in the H{sub 2}O-CH{sub 4}-NaCl system. A quantitative procedure for FT-IR micro-spectrometry has been developed to obtain, from individual petroleum fluid inclusions, mole % concentrations of methane, alkanes and carbon dioxide as constraints to thermodynamic modelling. Synthetic aqueous inclusions were created within quartz micro-fractures, with methane (from 150 deg C-200 bar), with petroleum (from 184 deg C-163 bar) and inside quartz overgrowth with the presence of hydrocarbons (from 277 deg C-300 bar). Synthetic petroleum inclusions were created with different water/oil ratios (W/O) within quartz micro-fractures (0quartz overgrowth (10

Petrogenesis of low-δ18O quartz porphyry dykes, Koegel Fontein complex, South Africa

Science.gov (United States)

Harris, Chris; Mulder, Kwenidyn; Sarkar, Saheli; Whitehead, Benjamin; Roopnarain, Sherissa

2018-04-01

This paper investigates the origin of low-δ18O quartz porphyry dykes associated with the 144-133 Ma Koegel Fontein Igneous Complex, which was intruded during the initial phase of breakup of Africa and South America. The 25-km diameter Rietpoort Granite is the largest and youngest phase of activity, and is roofed by a 10-km diameter pendant of gneiss. Quartz porphyry (QP) dykes, up to 15 m in width, strike NW-SE across the complex. The QP dykes that intruded outside the granite have similar quartz phenocryst δ18O values (average 8.0‰, ± 0.7, n = 33) to the granite (average 8.3 ± 1.0, n = 7). The QP dykes that intruded the roof pendant have quartz phenocrysts with more variable δ18O values (average 1.6‰, ± 2.1, n = 55). In some cases quartz phenocrysts have δ18O values as low as - 2.5‰. The variation in δ18O value within the quartz crystal population of individual dykes is small relative to the overall range, and core and rim material from individual quartz phenocrysts in three samples are identical within error. There is no evidence that quartz phenocryst δ18O values have been affected by fluid-rock interaction. Based on a Δquartz-magma value of 0.6‰, magma δ18O values must have been as low as - 3.1‰. Samples collected along the length of the two main QP dykes that traverse the roof pendant have quartz phenocryst δ18O values that range from + 1.1 to + 4.6‰, and - 2.3 to + 5.6‰, respectively. These δ18O values correlate negatively ( r = - 0.96) with initial 87Sr/86Sr, which can be explained by the event that lowered δ18O values of the source being older than the dykes. We suggest that the QP dykes were fed by magma produced by partial melting of gneiss, which had been variably altered at high temperature by 18O-depleted meteoric water during global glaciation at 550 Ma. The early melts had variable δ18O value but as melt pockets interconnected during melting, the δ18O values approached that of average gneiss. Variable quartz phenocryst �

Study of seed for synthetical quartz

International Nuclear Information System (INIS)

Suzuki, C.K.; Torikai, D.

1988-01-01

Natural quartz blocks for seed (synthetic quartz technology) were studied by using various characterization techniques, such as X-ray topography, optical micrography, inspectoscopy, polariscopy and conoscopy, and etching. One of the most commonly found defect is the electrical or Dauphine twin. In The present research, we have developed a methodology to obtain a highly perfect seed for the synthetic quartz industries. (author) [pt

Influence of Polycation Composition on Electrochemical Film Formation

Directory of Open Access Journals (Sweden)

Sabine Schneider

2018-04-01

Full Text Available The effect of polyelectrolyte composition on the electrodeposition onto platinum is investigated using a counterion switching approach. Film formation of preformed polyelectrolytes is triggered by oxidation of hexacyanoferrates(II (ferrocyanide, leading to polyelectrolyte complexes, which are physically crosslinked by hexacyanoferrate(III (ferricyanide ions due to preferential ferricyanide/polycation interactions. In this study, the electrodeposition of three different linear polyelectrolytes, namely quaternized poly[2-(dimethylaminoethyl methacrylate] (i.e., poly{[2-(methacryloyloxyethyl]trimethylammonium chloride}; PMOTAC, quaternized poly[2-(dimethylaminoethyl acrylate] (i.e., poly{[2-(acryloyloxyethyl]trimethylammonium chloride}; POTAC, quaternized poly[N-(3-dimethylaminopropylmethacrylamide] (i.e., poly{[3-(methacrylamidopropyl]trimethylammonium chloride}; PMAPTAC and different statistical copolymers of these polyelectrolytes with N-(3-aminopropylmethacrylamide (APMA, are studied. Hydrodynamic voltammetry utilizing a rotating ring disk electrode (RRDE shows the highest deposition efficiency DE for PMOTAC over PMAPTAC and over POTAC. Increasing incorporation of APMA weakens the preferred interaction of the quaternized units with the hexacyanoferrate(III ions. At a sufficient APMA content, electrodeposition can thus be prevented. Additional electrochemical quartz crystal microbalance measurements reveal the formation of rigid polyelectrolyte films being highly crosslinked by the hexacyanoferrate(III ions. Results indicate a different degree of water incorporation into these polyelectrolyte films. Hence, by adjusting the polycation composition, film properties can be tuned, while different chemistries can be incorporated into these electrodeposited thin hydrogel films.

Chemical Production of Graphene Catalysts for Electrochemical Energy Conversion

DEFF Research Database (Denmark)

Seselj, Nedjeljko

by scanning tunneling microscopy (STM), to investigate the nature of L-cysteine bonds on Au. Synthesized electrocatalysts were characterized by spectroscopic, microscopic and electrochemical techniques. Electrocatalysis was examined by electrochemical oxidation of formic acid, methanol and ethanol, and oxygen......Recently developed FC technology is among many approaches aiming at solving the global energy challenges. FCs are electrochemical devices that convert chemical energy from fuel molecules into electrical energy via electrochemical reactions. FCs are, however, limited by the scarce and expensive...... was achieved via L-cysteine linker molecules that provided pathways for fast electron transfers during the electrocatalytic reactions. Electrochemical properties of selfassembled L-cysteine monolayers immobilized on single-crystal Au(111) surfaces were studied in ionic liquids and their structures imaged...

Solid-state reactivity explored in situ by synchrotron radiation on single crystals: from SrFeO2.5 to SrFeO3 via electrochemical oxygen intercalation

International Nuclear Information System (INIS)

Maity, A; Dutta, R; Penkala, B; Ceretti, M; Letrouit-Lebranchu, A; Perichon, A; Paulus, W; Chernyshov, D; Piovano, A; Bossak, A; Meven, M

2015-01-01

In this study we demonstrate the feasibility of following up a chemical reaction by single crystal x-ray (synchrotron) diffraction under operando conditions, carried out in a specially designed electrochemical cell mounted on the BM01A at the European Synchrotron Radiation Facility (ESRF). We investigated in detail the electrochemical oxidation of SrFeO 2.5 to SrFeO 3 on a spherical single crystal of 70 µm diameter by in situ diffraction at an ambient temperature. Complete data sets were obtained by scanning the whole reciprocal space using a 2M Pilatus detector, resulting in 3600 frames with a resolution of 0.1° per data set, each obtained in 18 min. The crystal was mounted in a specially designed electrochemical cell with 1N KOH used as the electrolyte. During the electrochemical oxidation, the reaction proceeds following the phase sequence SrFeO 2.5 /SrFeO 2.75 /SrFeO 2.875 /SrFeO 3 , structurally accompanied by establishing a complex series of long-range oxygen vacancy ordering, which gets instantly organized at ambient temperature. The topotactic reaction pathway is discussed in terms of the evolution of the twin domain structure. The formation of SrFeO 2.875 is accompanied by the formation of diffuse streaks along the [1 0 0]-direction of the perovskite cell, reaching high d-spacings. The diffuse streaks are discussed and are thought to originate from a modified twin structure induced by the SrFeO 2.75 to SrFeO 2.875 transition, and the associated changes in the domain structure, developed during the oxygen intercalation. We equally analysed and discussed in detail the twin structure of all the title compounds. We confirm the ground state of SrFeO 2.5 is able to adopt the Imma space group symmetry, showing stacking faults of the tetrahedral layers along the stacking axis of the brownmillerite unit cell, indicated by the 1D diffuse rods. We showed that in situ single crystal diffraction has huge potential in the study of non-stoichiometric compounds

Solid-state reactivity explored in situ by synchrotron radiation on single crystals: from SrFeO2.5 to SrFeO3 via electrochemical oxygen intercalation

Science.gov (United States)

Maity, A.; Dutta, R.; Penkala, B.; Ceretti, M.; Letrouit-Lebranchu, A.; Chernyshov, D.; Perichon, A.; Piovano, A.; Bossak, A.; Meven, M.; Paulus, W.

2015-12-01

In this study we demonstrate the feasibility of following up a chemical reaction by single crystal x-ray (synchrotron) diffraction under operando conditions, carried out in a specially designed electrochemical cell mounted on the BM01A at the European Synchrotron Radiation Facility (ESRF). We investigated in detail the electrochemical oxidation of SrFeO2.5 to SrFeO3 on a spherical single crystal of 70 µm diameter by in situ diffraction at an ambient temperature. Complete data sets were obtained by scanning the whole reciprocal space using a 2M Pilatus detector, resulting in 3600 frames with a resolution of 0.1° per data set, each obtained in 18 min. The crystal was mounted in a specially designed electrochemical cell with 1N KOH used as the electrolyte. During the electrochemical oxidation, the reaction proceeds following the phase sequence SrFeO2.5/SrFeO2.75/SrFeO2.875/SrFeO3, structurally accompanied by establishing a complex series of long-range oxygen vacancy ordering, which gets instantly organized at ambient temperature. The topotactic reaction pathway is discussed in terms of the evolution of the twin domain structure. The formation of SrFeO2.875 is accompanied by the formation of diffuse streaks along the [1 0 0]-direction of the perovskite cell, reaching high d-spacings. The diffuse streaks are discussed and are thought to originate from a modified twin structure induced by the SrFeO2.75 to SrFeO2.875 transition, and the associated changes in the domain structure, developed during the oxygen intercalation. We equally analysed and discussed in detail the twin structure of all the title compounds. We confirm the ground state of SrFeO2.5 is able to adopt the Imma space group symmetry, showing stacking faults of the tetrahedral layers along the stacking axis of the brownmillerite unit cell, indicated by the 1D diffuse rods. We showed that in situ single crystal diffraction has huge potential in the study of non-stoichiometric compounds under operando

Highly efficient transparent Zn2SiO4:Mn2+ phosphor film on quartz glass

International Nuclear Information System (INIS)

Seo, K.I.; Park, J.H.; Kim, J.S.; Kim, G.C.; Yoo, J.H.

2009-01-01

Highly efficient transparent Zn 2 SiO 4 :Mn 2+ film phosphors on quartz substrates were deposited by the thermal diffusion of sputtered ZnO:Mn film. They show a textured structure with some preferred orientations. Our film phosphor shows, for the best photoluminescence (PL) brightness, a green PL brightness of about 20% of a commercial Zn 2 SiO 4 :Mn 2+ powder phosphor screen. The film shows a high transmittance of more than 10% at the red-color region. The excellence in PL brightness and transmittance can be explained in terms of the textured crystal growth with a continuous gradient of Zn 2 SiO 4 : Mn 2+ crystals.

Molecularly imprinted polymer based quartz crystal microbalance sensor system for sensitive and label-free detection of synthetic cannabinoids in urine.

Science.gov (United States)

Battal, Dilek; Akgönüllü, Semra; Yalcin, M Serkan; Yavuz, Handan; Denizli, Adil

2018-07-15

Herein, we prepared a novel quartz crystal microbalance (QCM) sensor for synthetic cannabinoids (JWH-073, JWH-073 butanoic acid, JWH-018 and JWH-018 pentanoic acid,) detection. Firstly, the synthetic cannabinoid (SCs) imprinted (MIP) and non-imprinted (NIP) nanoparticles were synthesized by mini-emulsion polymerization system. The SCs-imprinted nanoparticles were first characterized by SEM, TEM, zeta-size and FTIR-ATR analysis and then were dropped onto the gold QCM surface. The SCs-imprinted QCM sensor was characterized by an ellipsometer, contact angle, and AFM. The limit of detection was found as 0.3, 0.45, 0.4, 0.2 pg/mL JWH-018, JWH-073, JWH-018 pentanoic acid and JWH-073 butanoic acid, respectively. The selectivity of the SCs-imprinted QCM sensor was shown by using JWH-018, JWH-018 pentanoic acid, JWH-073 and JWH-073 butanoic acid. According to the results, the SCs-imprinted QCM sensors show highly selective and sensitive in a broad range of synthetic cannabinoid concentrations (0.0005-1.0 ng/mL) in both aqueous and synthetic urine solutions. Copyright © 2018 Elsevier B.V. All rights reserved.

1-Butyl-3-Methylimidazolium Tetrafluoroborate Film as a Highly Selective Sensing Material for Non-Invasive Detection of Acetone Using a Quartz Crystal Microbalance

Directory of Open Access Journals (Sweden)

Wenyan Tao

2017-01-01

Full Text Available Breath acetone serves as a biomarker for diabetes. This article reports 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4], a type of room temperature ionic liquid (RTIL, as a selective sensing material for acetone. The RTIL sensing layer was coated on a quartz crystal microbalance (QCM for detection. The sensing mechanism is based on a decrease in viscosity and density of the [bmim][BF4] film due to the solubilization of acetone leading to a positive frequency shift in the QCM. Acetone was detected with a linear range from 7.05 to 750 ppmv. Sensitivity and limit of detection were found to be 3.49 Hz/ppmv and 5.0 ppmv, respectively. The [bmim][BF4]-modified QCM sensor demonstrated anti-interference ability to commonly found volatile organic compounds in breath, e.g., isoprene, 1,2-pentadiene, d-limonene, and dl-limonene. This technology is useful for applications in non-invasive early diabetic diagnosis.

Quartz gauge response in ion radiation

International Nuclear Information System (INIS)

Taylor, P.E.; Gilbert, P.H.; Kernthaler, C.; Anderson, M.U.

1995-01-01

This paper describes recent work to make high quality quartz gauge (temporal and spatial) shock wave measurements in a pulsed ion beam environment. Intense ion beam radiation, nominally 1 MeV protons, was deposited into material samples instrumented with shunted quartz gauges adjacent to the ion deposition zone. Fluence levels were chosen to excite three fundamentally different material response modes (1) strong vapor, (2) combined vapor and melt phase and (3) thermoelastic material response. A unique quartz gauge design was utilized that employed printed circuit board (PCB) technology to facilitate electrical shielding, ruggedness, and fabrication at sign e meeting the essential one dimensional requirements of the characterized Sandia shunted quartz gauge. Shock loading and unloading experiments were conducted to evaluate the piezoelectric response of the coupled quartz gauge/PCB transducer. High fidelity shock wave profiles were recorded at the three ion fluence levels providing dynamic material response data for vapor, melt and solid material phases

Preparation and characterization of osmium hexacyanoferrate films and their electrocatalytic properties

Energy Technology Data Exchange (ETDEWEB)

Chen, S.-M. [Department of Chemical Engineering, National Taipei University of Technology, No. 1, Section 3, Chung-Hsiao East Road, Taipei, Taiwan 106 (China)]. E-mail: smchen78@ms15.hinet.net; Liao, C.-J. [Department of Chemical Engineering, National Taipei University of Technology, No. 1, Section 3, Chung-Hsiao East Road, Taipei, Taiwan 106 (China)

2004-11-15

Osmium hexacyanoferrate films have been prepared using repeated cyclic voltammetry, and the deposition process and the films' electrocatalytic properties in electrolytes containing various cations have been investigated. The cyclic voltammograms recorded the deposition of osmium hexacyanoferrate films directly from the mixing of Os{sup 3+} and Fe(CN){sub 6}{sup 3-} ions from solutions containing various cations. An electrochemical quartz crystal microbalance, cyclic voltammetry, and UV-visible spectroscopy were used to study the growth mechanism of the osmium hexacyanoferrate films. The osmium hexacyanoferrate films showed a single redox couple, and the redox reactions included 'electron transfer' and 'proton transfer' with a formal potential that demonstrates a proton effect in acidic solutions up to a 12 M aqueous HCl solution. The electrochemical and electrochemical quartz crystal microbalance results indicate that the redox process was confined to the immobilized osmium hexacyanoferrate film. The electrocatalytic reduction of dopamine, epinephrine, norepinephrine, S{sub 2}O{sub 3}{sup 2-}, and SO{sub 5}{sup 2-} by the osmium hexacyanoferrate films was performed. The preparation and electrochemical properties of co-deposited osmium(III) hexacyanoferrate and copper(II) hexacyanoferrate films were determined, and their two redox couples showed formal potentials that demonstrated a proton effect and an alkaline cation effect, respectively. Electrocatalytic reactions on the hybrid films were also investigated.

Quartz: structural and thermodynamic analyses across the α ↔ β transition with origin of negative thermal expansion (NTE) in β quartz and calcite

Energy Technology Data Exchange (ETDEWEB)

Antao, Sytle M.

2016-04-01

The temperature variation,T, of the crystal structure of quartz, SiO₂, from 298 to 1235 K was obtained with synchrotron powder X-ray diffraction data and Rietveld structure refinements. The polymorphic transformation fromP3₂21 (low-T, α quartz) toP6₂22 (high-T, β quartz) occurs at a transition temperature,T_tr= 847 K. TheTvariations of spontaneous strains and several structural parameters are fitted to an order parameter,Q, using Landau theory. The change in Si atom coordinate, Si_x, givesT_tr-T_c= 0.49 K, which indicates an α ↔ β transition that is weakly first order and nearly tricritical in character (Q⁴∝T). Strains give higherT_tr-T_cvalues (≃ 7 K). Other fitted parameters are the oxygen O_zcoordinate, Si—Si distance, Si—O—Si and φ angles, and intensity of the (111) reflection,I₁₁₁. In α quartz, the Si—Si distance increases withTbecause of cation repulsion, so the Si—O—Si angle increases (and φ decreases) and causes the thermal expansion of the framework structure that consists of corner-sharing distorted rigid SiO₄tetrahedra. The Si—Si distances contract withTand cause negative thermal expansion (NTE) in β quartz because of increasing thermal librations of the O atom in the Si—O—Si linkage that occur nearly perpendicular to the Si—Si contraction. In calcite, CaCO₃, the short Ca—Ca distance expands withT, but the next-nearest Ca—Ca distance, which is of equal length to theaaxis, contracts withTand causes NTE along

Gamma radiation of quartz from Entre Rios (SC) and QuaraÍ (RS)

International Nuclear Information System (INIS)

Enokihara, Cyro T.; Rela, Paulo R.; Schultz-Güttler, Rainer A.

2017-01-01

The availability of gamma ray irradiators in Brazil increased the possibilities of treatments of gemstones for color enhancements. One of the minerals with a very high potential of these treatments is quartz, a very widespread mineral with many colored commercial varieties. A specific variety of quartz showing a green color in nature or induced artificially by radiation gamma ( 60 Co) is quite rare. In Brazil the widely scattered geode occurrences along a 600 km stretch from Quaraí at Brazil southernmost tip to Uberlandia in Minas Gerais is one of these. Quartz from these 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 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 located near the towns Entre Rios (SC) and Quaraí (RS). To characterize these materials analyses have been made by ICP, NAA, electron microscopy, water loss techniques and UV-VIS and NIR-FTIR spectroscopic measurements. Silanol complexes are found, which by radiation due to gamma rays form the color center NBOHC (Non-Bonding Oxygen Hole Center), showing absorption between 590 to 620 nm and leaving a transmission window at about 550nm, responsible for the green color. The spectroscopic water determination showed less molecular water (up to 2300 ppm by weight), probably due to remaining silanol complexes.The water content with up to 3200 ppm by weight exceeds the amount of charge balancing cations (Fe, Al, Li). (author)

Gamma radiation of quartz from Entre Rios (SC) and QuaraÍ (RS)

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 Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Schultz-Güttler, Rainer A., E-mail: rainersgut@gmail.com [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Geociências

2017-07-01

The availability of gamma ray irradiators in Brazil increased the possibilities of treatments of gemstones for color enhancements. One of the minerals with a very high potential of these treatments is quartz, a very widespread mineral with many colored commercial varieties. A specific variety of quartz showing a green color in nature or induced artificially by radiation gamma ({sup 60}Co) is quite rare. In Brazil the widely scattered geode occurrences along a 600 km stretch from Quaraí at Brazil southernmost tip to Uberlandia in Minas Gerais is one of these. Quartz from these 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 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 located near the towns Entre Rios (SC) and Quaraí (RS). To characterize these materials analyses have been made by ICP, NAA, electron microscopy, water loss techniques and UV-VIS and NIR-FTIR spectroscopic measurements. Silanol complexes are found, which by radiation due to gamma rays form the color center NBOHC (Non-Bonding Oxygen Hole Center), showing absorption between 590 to 620 nm and leaving a transmission window at about 550nm, responsible for the green color. The spectroscopic water determination showed less molecular water (up to 2300 ppm by weight), probably due to remaining silanol complexes.The water content with up to 3200 ppm by weight exceeds the amount of charge balancing cations (Fe, Al, Li). (author)

A nanogravimmetric investigation of the charging processes on ruthenium oxide thin films and their effect on methanol oxidation

International Nuclear Information System (INIS)

Santos, M.C.; Cogo, L.; Tanimoto, S.T.; Calegaro, M.L.; Bulhoes, L.O.S

2006-01-01

The charging processes and methanol oxidation that occur during the oxidation-reduction cycles in a ruthenium oxide thin film electrode (deposited by the sol-gel method on Pt covered quartz crystals) were investigated by using cyclic voltammetry, chronoamperometry and electrochemical quartz crystal nanobalance techniques. The ruthenium oxide rutile phase structure was determined by X-ray diffraction analysis. The results obtained during the charging of rutile ruthenium oxide films indicate that in the anodic sweep the transition from Ru(II) to Ru(VI) occurs followed by proton de-intercalation. In the cathodic sweep, electron injection occurs followed by proton intercalation, leading to Ru(II). The proton intercalation/de-intercalation processes can be inferred from the mass/charge relationship which gives a slope close to 1 g mol -1 (multiplied by the Faraday constant) corresponding to the molar mass of hydrogen. From the chronoamperometric measurements, charge and mass saturation of the RuO 2 thin films was observed (440 ng cm -2 ) during the charging processes, which is related to the total number of active sites in these films. Using the electrochemical quartz crystal nanobalance technique to study the methanol oxidation reaction at these films was possible to demonstrate that bulk oxidation occurs without the formation of strongly adsorbed intermediates such as CO ads , demonstrating that Pt electrodes modified by ruthenium oxide particles can be promising catalysts for the methanol oxidation as already shown in the literature

EQCM Study of Influence of Anion Nature on Electrochemical Reduction of Bismuth Sulfide in Nickel Plating Solution

Directory of Open Access Journals (Sweden)

Loreta TAMAŠAUSKAITĖ-TAMAŠIŪNAITĖ

2011-03-01

Full Text Available The influence of anion nature on the reduction of bismuth sulfide film deposited on gold using the successive ionic layer adsorption and reaction method in solutions containing Ni2+ ions has been investigated by electrochemical quartz crystal microbalance combined with cyclic voltammetry and X-ray photoelectron spectroscopy. It has been determined that the reduction of bismuth sulfide film in the nickel plating solution depends on the anion nature: larger cathodic current and mass changes (Dƒ are observed in the solution containing acetate anion as compared to those in the solution containing sulfate anion. As the reduction of bismuth sulfide film in the background solutions depends on the nature of anion, it influences the cathodic reduction of Ni2+ ions prior to OPD of Ni. A greater current and mass change (Dƒ is conditioned by simultaneously occurring reduction of bismuth sulfide film when the film is reduced in the acetate nickel plating electrolyte in contrast to that in the sulfate one.http://dx.doi.org/10.5755/j01.ms.17.1.244

Hexamethyldisiloxane thin films as sensitive coating for quartz crystal microbalance based volatile organic compounds sensors

International Nuclear Information System (INIS)

Boutamine, M.; Bellel, A.; Sahli, S.; Segui, Y.; Raynaud, P.

2014-01-01

Hexamethyldisiloxane (HMDSO) thin films coated quartz crystal microbalance (QCM) electrodes have been characterized for the detection of volatile organic compounds (VOCs). The sensitive coatings were plasma polymerized in pure vapor of HMDSO and HMDSO/O 2 mixture. The sensor sensitivity was evaluated by monitoring the frequency shift (∆f) of the coated QCM electrode exposed to different concentrations of VOC vapors, such as ethanol, methanol, benzene and chloroform. The isotherm response characteristics showed good reproducibility and reversibility. For all types of analyte, ∆f were found to be linearly correlated with the concentration of VOC vapor. It was shown that it is possible to tune the chemical affinity of the sensor by changing the oxygen ratio in the deposition gas mixture. Contact angle measurements (CA), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to study surface wettability, chemical composition and surface morphology of the coated QCM electrodes. ATR-FTIR analysis showed the presence of methyl groups around 840 cm −1 due to Si-(CH 3 ) 3 rocking vibration making the elaborated sensor surface hydrophobic. When the coating is performed in HMDSO/O 2 mixture, AFM and SEM images showed an increase in the effective specific surface area of the sensor due to the increase in surface roughness. Surface morphology combined with chemical composition significantly affects the sensitivity of the QCM-based sensor. - Highlights: • Hexamethyldisiloxane layers were evaluated for volatile organic compounds detection. • The kinetic response of the sensor showed good reproducibility and reversibility. • Hydrophobic coating and high specific surface area increase the sensor sensitivity. • Sensor affinity can be controlled by controlling oxygen proportion in the mixture

Synthesis, Crystal Structure, Luminescence, Electrochemical and Antimicrobial Properties of Bis(salamo-Based Co(II Complex

Directory of Open Access Journals (Sweden)

Li Wang

2017-09-01

Full Text Available A newly designed Co(II complex, [Co3(L(OAc2(CH3OH2]·CH3OH, by the reaction of a bis(salamo-type tetraoxime ligand (H4L with Co(II acetate tetrahydrate was synthesized and characterized by elemental analyses, IR, UV-vis spectra and single-crystal X-ray crystallography. The UV-vis titration experiment manifested that a trinuclear (L:M = 1:3 complex was formed. It is worth noting that the two terminal Co(II (Co1 and Co3 atoms of the Co(II complex have different coordination modes and geometries unreported earlier. Furthermore, through intermolecular interactions (C–H···O, C–H···π and O–H···O, a 2D layer-like network is constructed. In addition, the fluorescence behaviors, antimicrobial activities and electrochemical properties of H4L and its Co(II complex were investigated.

ESR signals in quartz for the studies of earth surface processes

Science.gov (United States)

Toyoda, S.; Shimada, A., , Dr; Takada, M.

2017-12-01

Various ESR (electron spin resonance) signals are observed in quartz. As they are formed by natural radiation, the signals are useful in dating of geological events, such as volcanic eruption, faulting and sedimentation. It was also found that those paramagnetic defects can be fingerprints of sediments, to be used for studies in sediment provenance. The signal of the E1' center, unpaired electron at an oxygen vacancy, was first used for such studies. A method was proposed to estimate the number of the precursors (oxygen vacancies) from the E1' center intensity. The number of oxygen vacancies in quartz was found to have positive correlation with the crystallization age. Using this feature, studies were quite successful in aeolian dust. It was shown that the sources of aeolian dust deposited in northern part of Japanese Islands were different between in MIS1 and MIS 2. In combination with crystallinity index, the contributions of the dust components from three origins were quantitatively obtained. After these, the provenance studies on river sediments have started where the impurity centers in quartz were employed, which are the Al center, the Ti centers, and the Ge centers. Sediments of Kizu River, Mie to Nara prefectures in Central Japan are most extensively studied. Firstly, it was shown that each of possible sources of granitic quartz around the reaches has respective characteristics in the number of oxygen vacancies and the signal intensities of impurity centers. Secondary, by the artificial mixing experiments, the impurity signal intensities have the values consistent with the mixing ratio of the two samples of quartz with different intensities. At river junctions, the mixing ratios were calculated from the ESR signals. At some locations, the mixing ratio values obtained from one signal were consistent with the ones from another signal while at some locations they were not. The latter inconsistent results would indicate that the river sediments are

Molecular assembly and electro polymerization of 3,4-ethylenedioxy thiophene on Au(100) single crystal electrode using in-situ electrochemical scanning tunneling microscopy

International Nuclear Information System (INIS)

Garcia, Jonyl L.; Tongol, Bernard John V.; ShuehLin Yau

2012-01-01

Electrochemical scanning tunneling microscopy (Ec-STM) is a powerful technique that can provide molecular-level information regarding electrode surface processes in-situ in electrolyte solvent under ambient conditions. In this study, the adsorption and electro polymerization of an industrially important conducting polymer precursor, 3,4-ethylenedioxy thiophene (EDOT), on Au (100) single crystal was probed using Ec-STM. The Au (100) single crystal electrode substrate used for this study was fabricated using the well-known Clavilier's flame melting procedure. Cyclic voltammetry (CV) was used along with Ec-STM to characterize the bare, EDOT-modified, and poly(EDOT)-modified Au (100) single crystal electrode. Time-dependent Ec-STM imaging at 0.550 V showed the formation of an EDOT self-assembled monolayer through 2-D surface dillusion. The resulting EDOT molecular assembly on Au (100) single crystal electrode was found to fit in a 4√2χ3√2 unit cell. Difference in apparent corrugation between molecular rows was attributed to different angular orientation with respect to the substrate. The electro polymerization of EDOT on Au (100) single crystal electrode was done by potentiostatic and potentiodynamic methods. Both methods suggested a solution-process mechanism for EDOT electro polymerization. (author)

Using quartz and plagioclase to gain insight into chemical and thermal evolution of the Rotoiti magma prior to the caldera-forming eruption {+-}55 ka, New Zealand

Energy Technology Data Exchange (ETDEWEB)

Smith, Victoria [Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queen' s Road, Bristol BS8 1RJ (United Kingdom); Shane, Phil [School of Geography, Geology and Environmental Science, University of Auckland, Private Bag 92019, Auckland (New Zealand); Nairn, Ian [45 Summit Road, Rotorua RD5, New Zealand and GNS Science, Wairakei Research Centre, Taupo (New Zealand)], E-mail: Victoria.Smith@bristol.ac.uk

2008-10-01

The zoned plagioclase and quartz crystals within the multiple magmas that erupted during the {approx}55 ka Rotoiti caldera forming eruption appear to have had complex thermal and compositional histories. Compositional zoning suggests that magmatic systems were open, and received multiple pulses of hotter and more mafic magma. Limited diffusion across the crystals indicates that crystals did not dwell at magmatic temperatures for prolonged periods (<100 years), and suggest that the melts were generated and erupted quickly.

Trend of telomerase activity change during human iPSC self-renewal and differentiation revealed by a quartz crystal microbalance based assay

Science.gov (United States)

Zhou, Yitian; Zhou, Ping; Xin, Yinqiang; Wang, Jie; Zhu, Zhiqiang; Hu, Ji; Wei, Shicheng; Ma, Hongwei

2014-11-01

Telomerase plays an important role in governing the life span of cells for its capacity to extend telomeres. As high activity of telomerase has been found in stem cells and cancer cells specifically, various methods have been developed for the evaluation of telomerase activity. To overcome the time-consuming procedures and complicated manipulations of existing methods, we developed a novel method named Telomeric Repeat Elongation Assay based on Quartz crystal microbalance (TREAQ) to monitor telomerase activity during the self-renewal and differentiation of human induced pluripotent stem cells (hiPSCs). TREAQ results indicated hiPSCs possess invariable telomerase activity for 11 passages on Matrigel and a steady decline of telomerase activity when differentiated for different periods, which is confirmed with existing golden standard method. The pluripotency of hiPSCs during differentiation could be estimated through monitoring telomerase activity and compared with the expression levels of markers of pluripotency gene via quantitative real time PCR. Regular assessment for factors associated with pluripotency or stemness was expensive and requires excessive sample consuming, thus TREAQ could be a promising alternative technology for routine monitoring of telomerase activity and estimate the pluripotency of stem cells.

Probing Interfacial Friction and Dissipation in Granular Gold­ Nickel Alloys with a Quartz Crystal Oscillator in an External Magnetic Field

Science.gov (United States)

Stevens, K. M.; Krim, J.

2015-03-01

We present here a quartz crystal microbalance study of two-phase gold nickel alloys whose internal granular properties are probed by exposure to a fluctuating external magnetic field. The work is motivated by prior studies demonstrating that granular two-phase materials exhibited lower friction and wear than solid solution alloys with identical compositions. In particular, we report a ``flexing'' effect which appears when an external magnetic field is applied, and is manifested as a decrease in the magnitude of oscillation amplitude that is synchronized with the applied field; the effect is not seen on the complimentary solid solution samples. The effect is consistent with internal interfacial friction between nickel and gold grains, indicating a degree of freedom which may decrease friction even in the absence of an external magnetic field. This is supported through analysis of energy dissipation in the system, using the Butterworth­-Van Dyke equivalent circuit model. Data and interpretation are also presented that rule out alternate explanations such as giant magnetoresistance and/or other resistive phenomenon within the film. Funding provided by NSF DMR0805204. Thanks to L. Pan for sample preparation.

Salinity of the Archaean oceans from analysis of fluid inclusions in quartz

Science.gov (United States)

Marty, Bernard; Avice, Guillaume; Bekaert, David V.; Broadley, Michael W.

2018-05-01

Fluids trapped in inclusions in well-characterized Archaean hydrothermal quartz crystals were analyzed by the extended argon-argon method, which permits the simultaneous measurement of chlorine and potassium concentrations. Argon and nitrogen isotopic compositions of the trapped fluids were also determined by static mass spectrometry. Fluids were extracted by stepwise crushing of quartz samples from North Pole (NW Australia) and Barberton (South Africa) 3.5-3.0-Ga-old greenstone belts. The data indicate that fluids are a mixture of a low salinity end-member, regarded as the Archaean oceanic water, and several hydrothermal end-members rich in Cl, K, N, and radiogenic parentless 40Ar. The low Cl-K end-member suggests that the salinity of the Archaean oceans was comparable to the modern one, and that the potassium content of the Archaean oceans was lower than at present by about 40%. A constant salinity of the oceans through time has important implications for the stabilization of the continental crust and for the habitability of the ancient Earth.

Chromium(III) Complex Obtained from Dipicolinic Acid: Synthesis, Characterization, X-Ray Crystal Structure and Electrochemical Studies

Energy Technology Data Exchange (ETDEWEB)

Ghasemi, Khaled; Rezvani, Ali Reza; Ghasemi, Fatemeh [Univ. of Sistan and Baluchestan, Zahedan (Iran, Islamic Republic of); Razak, Ibrahim Abdul; Rosli, Mohd Mustaqim [Universiti Sains Malaysia, Penang (Malaysia)

2013-10-15

The synthesis, X-ray crystallography, spectroscopic (IR, UV-vis), and electrochemical properties of the title compound, [H{sub 3}O][Cr(dipic){sub 2}] [H{sub 3}O{sup +}.Cl{sup -}] (1), (H{sub 2}dipic = 2,6-pyridinedicarboxylic acid), are reported. This complex crystallizes in the monoclinic space group Cc with a = 14.9006(10) A, b = 12.2114(8) A, c = 8.6337(6) A, α = 90.00 .deg., β = 92.7460(10) .deg., γ = 90.00 .deg., and V = 1569.16(18) A3 with Z = 4. The hydrogen bonding and noncovalent interactions play roles in the stabilization of the structure. In order to gain a better understanding of the most important geometrical parameters in the structure of the complex, atoms in molecules (AIM) method at B3LYP/6-31G level of theory has been employed.

Atomic motion of resonantly vibrating quartz crystal visualized by time-resolved X-ray diffraction

International Nuclear Information System (INIS)

Aoyagi, Shinobu; Osawa, Hitoshi; Sugimoto, Kunihisa; Fujiwara, Akihiko; Takeda, Shoichi; Moriyoshi, Chikako; Kuroiwa, Yoshihiro

2015-01-01

Transient atomic displacements during a resonant thickness-shear vibration of AT-cut α-quartz are revealed by time-resolved X-ray diffraction under an alternating electric field. The lattice strain resonantly amplified by the alternating electric field is ∼10 4 times larger than that induced by a static electric field. The resonantly amplified lattice strain is achieved by fast displacements of oxygen anions and collateral resilient deformation of Si−O−Si angles bridging rigid SiO 4 tetrahedra, which efficiently transduce electric energy into elastic energy

Shock pressure estimation in basement rocks of the Chicxulub impact crater using cathodoluminescence spectroscopy of quartz

Science.gov (United States)

Tomioka, N.; Tani, R.; Kayama, M.; Chang, Y.; Nishido, H.; Kaushik, D.; Rae, A.; Ferrière, L.; Gulick, S. P. S.; Morgan, J. V.

2017-12-01

The Chicxulub impact structure, located in the northern Yucatan Peninsula, Mexico, was drilled by the joint IODP-ICDP Expedition 364 in April-May 2016. This expedition is the first attempt to obtain materials from the topographic peak ring within the crater previously identified by seismic imaging. A continuous core was successfully recovered from the peak ring at depths between 505.7 and 1334.7 mbsf. Uplifted, fractured, and shocked granitic basement rocks forming the peak ring were found below, in the impact breccia and impact melt rock unit (747.0-1334.7 mbsf; Morgan et al. 2016). In order to constrain impact crater formation, we investigated shock pressure distribution in the peak-ring basement rocks. Thin sections of the granitic rocks were prepared at intervals of 60 m. All the samples contains shocked minerals, with quartz grains frequently showing planar deformation features (PDFs). We determined shock pressures based on the cathodoluminescence (CL) spectroscopy of quartz. The strong advantage of the CL method is its applicability to shock pressure estimation for individual grains for both quartz and diaplectic SiO2 glass with high-spatial resolution ( 1 μm) (Chang et al. 2016). CL spectra of quartz shows a blue emission band caused by shock-induced defect centers, where its intensity increases with shock pressure. A total of 108 quartz grains in ten thin sections were analyzed using a scanning electron microscope with a CL spectrometer attached (an acceleration voltage of 15 kV and a beam current of 2 nA were used). Natural quartz single crystals, which were experimentally shocked at 0-30 GPa, were used for pressure calibration. CL spectra of all the quartz grains in the basement rocks showed broad blue emission band at the wavelength range of 300-500 nm and estimated shock pressures were in the range of 15-20 GPa. The result is consistent with values obtained from PDFs analysis in quartz using the universal stage (Ferrière et al. 2017; Rae et al. 2017

Additive manufacturing of transparent fused quartz

Science.gov (United States)

Luo, Junjie; Hostetler, John M.; Gilbert, Luke; Goldstein, Jonathan T.; Urbas, Augustine M.; Bristow, Douglas A.; Landers, Robert G.; Kinzel, Edward C.

2018-04-01

This paper investigates a filament-fed process for additive manufacturing (AM) of fused quartz. Glasses such as fused quartz have significant scientific and engineering applications, which include optics, communications, electronics, and hermetic seals. AM has several attractive benefits such as increased design freedom, faster prototyping, and lower processing costs for small production volumes. However, current research into glass AM has focused primarily on nonoptical applications. Fused quartz is studied here because of its desirability for use in high-quality optics due to its high transmissivity and thermal stability. Fused quartz filaments are fed into a CO2 laser-generated molten region, smoothly depositing material onto the workpiece. Spectroscopy and pyrometry are used to measure the thermal radiation incandescently emitted from the molten region. The effects of the laser power and scan speed are determined by measuring the morphology of single tracks. Thin walls are printed to study the effects of layer-to-layer height. This information is used to deposit solid pieces including a cylindrical-convex shape capable of focusing visible light. The transmittance and index homogeneity of the printed fused quartz are measured. These results show that the filament-fed process has the potential to print transmissive optics.

Preparation of a molecularly imprinted sensor based on quartz crystal microbalance for specific recognition of sialic acid in human urine.

Science.gov (United States)

Qiu, Xiuzhen; Xu, Xian-Yan; Chen, Xuncai; Wu, Yiyong; Guo, Huishi

2018-05-08

A novel molecularly imprinted quartz crystal microbalance (QCM) sensor was successfully prepared for selective determination of sialic acid (SA) in human urine samples. To obtain the QCM sensor, we first modified the gold surface of the QCM chip by self-assembling of allylmercaptane to introduce polymerizable double bonds on the chip surface. Then, SA molecularly imprinted polymer (MIP) nanofilm was attached to the modified QCM chip surface. For comparison, we have also characterized the nonmodified and improved surfaces of the QCM sensor by using atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy. We then tested the selectivity and detection limit of the imprinted QCM sensor via a series of adsorption experiments. The results show a linear response in the range of 0.025-0.50 μmol L -1 for sialic acid. Moreover, the limit of detection (LOD) of the prepared imprinted QCM sensor was found to be 1.0 nmol L -1 for sialic acid, and high recovery values range from 87.6 to 108.5% with RSD sensor was developed and used to detect sialic acid in human urine samples. Graphical abstract Specific recognition of sialic acid by the MIP-QCM sensor system.

Thermally Reduced Graphene Oxide Electrochemically Activated by Bis-Spiro Quaternary Alkyl Ammonium for Capacitors.

Science.gov (United States)

He, Tieshi; Meng, Xiangling; Nie, Junping; Tong, Yujin; Cai, Kedi

2016-06-08

Thermally reduced graphene oxide (RGO) electrochemically activated by a quaternary alkyl ammonium-based organic electrolytes/activated carbon (AC) electrode asymmetric capacitor is proposed. The electrochemical activation process includes adsorption of anions into the pores of AC in the positive electrode and the interlayer intercalation of cations into RGO in the negative electrode under high potential (4.0 V). The EA process of RGO by quaternary alkyl ammonium was investigated by X-ray diffraction and electrochemical measurements, and the effects of cation size and structure were extensively evaluated. Intercalation by quaternary alkyl ammonium demonstrates a small degree of expansion of the whole crystal lattice (d002) and a large degree of expansion of the partial crystal lattice (d002) of RGO. RGO electrochemically activated by bis-spiro quaternary alkyl ammonium in propylene carbonate/AC asymmetric capacitor exhibits good activated efficiency, high specific capacity, and stable cyclability.

Electrochemical lithiation of thin silicon based layers potentiostatically deposited from ionic liquid

International Nuclear Information System (INIS)

Vlaic, Codruta Aurelia; Ivanov, Svetlozar; Peipmann, Ralf; Eisenhardt, Anja; Himmerlich, Marcel; Krischok, Stefan; Bund, Andreas

2015-01-01

Thin silicon layers containing about 20% carbon and 20% oxygen were deposited on copper substrates by potentiostatic electroreduction from a 1 M SiCl 4 1-butyl-1-methyl-pyrrolidinium bis (trifluoromethyl) sulfonylimide [BMP][TFSI] electrolyte. The electrodeposition process was investigated by means of voltammetric techniques, coupled with in-situ microgravimetry (quartz crystal microbalance, QCM). The electrochemical and QCM data suggest a possible contribution of a partial Si 4+ to Si 2+ reduction and/or a restructuring of the metallic substrate. Considerable impact of side reactions parallel to the deposition process was indicated by QCM measurements performed under potentiostatic and potentiodynamic conditions. The deposition of silicon-based films was confirmed by energy dispersive X-ray analysis (EDX). Analysis of the chemical composition of the deposit and its elemental distribution were achieved by depth profiling X-ray photoelectron spectroscopy (XPS). The electrodeposited silicon containing layers showed stable lithiation and delithiation with capacity values of about 1200 mAhg −1 and 80% capacity retention after 300 cycles in standard EC/DMC electrolytes. In ionic liquid (IL) the material displayed lower capacity of ca. 500 mAhg −1 , which can be attributed to the higher viscosity of this electrolyte and deposition of IL decomposition products during lithiation

Binary iron sulfides as anode materials for rechargeable batteries: Crystal structures, syntheses, and electrochemical performance

Science.gov (United States)

Xu, Qian-Ting; Li, Jia-Chuang; Xue, Huai-Guo; Guo, Sheng-Ping

2018-03-01

Effective utilization of energy requires the storage and conversion device with high ability. For well-developed lithium ion batteries (LIBs) and highly developing sodium ion batteries (SIBs), this ability especially denotes to high energy and power densities. It's believed that the capacity of a full cell is mainly contributed by anode materials. So, to develop inexpensive anode materials with high capacity are meaningful for various rechargeable batteries' better applications. Iron is a productive element in the crust, and its oxides, sulfides, fluorides, and oxygen acid salts are extensively investigated as electrode materials for batteries. In view of the importance of electrode materials containing iron, this review summarizes the recent achievements on various binary iron sulfides (FeS, FeS2, Fe3S4, and Fe7S8)-type electrodes for batteries. The contents are mainly focused on their crystal structures, synthetic methods, and electrochemical performance. Moreover, the challenges and some improvement strategies are also discussed.

Using quartz and plagioclase to gain insight into chemical and thermal evolution of the Rotoiti magma prior to the caldera-forming eruption ±55 ka, New Zealand

International Nuclear Information System (INIS)

Smith, Victoria; Shane, Phil; Nairn, Ian

2008-01-01

The zoned plagioclase and quartz crystals within the multiple magmas that erupted during the ∼55 ka Rotoiti caldera forming eruption appear to have had complex thermal and compositional histories. Compositional zoning suggests that magmatic systems were open, and received multiple pulses of hotter and more mafic magma. Limited diffusion across the crystals indicates that crystals did not dwell at magmatic temperatures for prolonged periods (<100 years), and suggest that the melts were generated and erupted quickly.

Pressure-induced drastic collapse of a high oxygen coordination shell in quartz-like α-GeO2

International Nuclear Information System (INIS)

Dong, Juncai; Zhang, Xiaoli; Wu, Ziyu; Chen, Dongliang; Zhang, Qian; Wu, Ye; Wu, Xiang

2014-01-01

With the combination of a single crystal diamond anvil cell and a polycapillary half-lens, the local structural evolution around germanium in tetrahedrally networked quartz-like α-GeO 2 has been investigated using extended x-ray absorption fine structure spectroscopy of up to 14 GPa by multiple-scattering analysis method. While the first shell Ge–O bond distances show a slight contraction with increasing pressure, the third shell Ge–O bond distances are found to decrease dramatically. The sluggish lengthening of the first shell Ge–O bond distances, initiated by coordination increase from fourfold to sixfold, occurs in the 7–14 GPa range just when the third shell Ge–O bond distances fall in the region of the second shell Ge–Ge bond distances. Moreover, these features are accompanied by the closing of intertetrahedral Ge–O–Ge angles and the opening of two intratetrahedral O–Ge–O angles, whose topological configuration surprisingly exhibits a helical chirality along the c axis that is opposite to the double helices of the corner-linked GeO 4 tetrahedra. These results suggest that the high-pressure phase transitions in quartz and quartz-like materials could be associated with a structural instability that is driven by the drastic collapse of the next-nearest-neighbour anion shell, which is consistent with the emergence of high-symmetry anion sublattice. Our findings provide crucial insights into the densification mechanisms of quartz-like oxides, which would have broad implications for our understanding of the metastability of various post-quartz crystalline phases and pressure-induced amorphization. (paper)

Quartz-Enhanced Photoacoustic Spectroscopy: A Review

Science.gov (United States)

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

2014-01-01

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. PMID:24686729

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.

In situ anodization of aluminum surfaces studied by x-ray reflectivity and electrochemical impedance spectroscopy

International Nuclear Information System (INIS)

Bertram, F.; Evertsson, J.; Messing, M. E.; Mikkelsen, A.; Lundgren, E.; Zhang, F.; Pan, J.; Carlà, F.; Nilsson, J.-O.

2014-01-01

We present results from the anodization of an aluminum single crystal [Al(111)] and an aluminum alloy [Al 6060] studied by in situ x-ray reflectivity, in situ electrochemical impedance spectroscopy and ex situ scanning electron microscopy. For both samples, a linear increase of oxide film thickness with increasing anodization voltage was found. However, the slope is much higher in the single crystal case, and the break-up of the oxide film grown on the alloy occurs at a lower anodization potential than on the single crystal. The reasons for these observations are discussed as are the measured differences observed for x-ray reflectivity and electrochemical impedance spectroscopy.

Aberrant thermoluminescence dates obtained from primary volcanic quartz

International Nuclear Information System (INIS)

Guerin, Gilles; Samper, Agnes

2007-01-01

This study deals with the dating by thermoluminescence (TL) of quartz from six volcanic formations of the Saint Lucia Island (Lesser Antilles Arc). Quartz microcrystals up to one millimetre in size were extracted from dacites and pumice flows and prepared in a way similar to the well-known inclusion technique. The TL properties of these quartz were used to estimate apparent palaeodoses using the multi-aliquot protocol. The quartz TL was studied in three different spectral domains: red, green and ultraviolet/blue. The calculated annual dose-rates yielded a set of 18 age-estimates. For some samples complementary dates were obtained using high temperature TL (HTTL) of plagioclase feldspars. These latter dates combined with previously determined radiocarbon and unspiked K-Ar dates were used to explore the validity of ages computed from the TL of quartz. Individual values for quartz appear to be scattered and do not match ages deduced from 14 C, unspiked K-Ar or HTTL on plagioclase dates. These results indicate that when conventional TL methodologies derived from the inclusion method are applied to volcanic quartz major dating problems are to be expected

Aberrant thermoluminescence dates obtained from primary volcanic quartz

Energy Technology Data Exchange (ETDEWEB)

Guerin, Gilles [Laboratoire des Sciences du Climat et de l' Environnement, CEA-CNRS, avenue de la Terrasse, 91191 Gif-sur-Yvette (France)], E-mail: gilles.guerin@u-psud.fr; Samper, Agnes [Laboratoire de geochronologie multitechnique (UPS-IPGP), Universite de Paris-Sud Orsay, 91405 Orsay Cedex (France)

2007-10-15

This study deals with the dating by thermoluminescence (TL) of quartz from six volcanic formations of the Saint Lucia Island (Lesser Antilles Arc). Quartz microcrystals up to one millimetre in size were extracted from dacites and pumice flows and prepared in a way similar to the well-known inclusion technique. The TL properties of these quartz were used to estimate apparent palaeodoses using the multi-aliquot protocol. The quartz TL was studied in three different spectral domains: red, green and ultraviolet/blue. The calculated annual dose-rates yielded a set of 18 age-estimates. For some samples complementary dates were obtained using high temperature TL (HTTL) of plagioclase feldspars. These latter dates combined with previously determined radiocarbon and unspiked K-Ar dates were used to explore the validity of ages computed from the TL of quartz. Individual values for quartz appear to be scattered and do not match ages deduced from {sup 14}C, unspiked K-Ar or HTTL on plagioclase dates. These results indicate that when conventional TL methodologies derived from the inclusion method are applied to volcanic quartz major dating problems are to be expected.

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...

Assessment of the potential for dating secondary calcite and quartz in fault zones

International Nuclear Information System (INIS)

Morency, Maurice

1982-03-01

Calcite and quartz occur frequently as secondary minerals in faults. In many instances these minerals are not deformed. Calcite, for example, often exhibits an undisturbed fibrous habit or appears as euhedral crystals. Direct dating of euhedral crystals would provide a minimum age of the last movement along a fault, whereas dating of fibrous crystals would furnish the real age of the last movement. This information would be essential in the evaluation and selection of sites for both nuclear power reactors and nuclear waste disposal. In the Canadian context, to be successful, the technique should be able to date minerals as old as tens of millions of years. In this study both isotopic and radioactive damage techniques were considered. It was found that thermoluminescence, thermally stimulated current, and electron spin resonance offer possibilities. Recent electron spin resonance studies of ancient flints have yielded dates of several hundred million years. It is anticipated that in the near future a combination of the above techniques will be extensively used in the field of geochronology

A High Sensitivity Preamplifier for Quartz Tuning Forks in QEPAS (Quartz Enhanced PhotoAcoustic Spectroscopy Applications

Directory of Open Access Journals (Sweden)

Tomasz Starecki

2017-11-01

Full Text Available All the preamplifiers dedicated for Quartz Enhanced PhotoAcoustic Spectroscopy (QEPAS applications that have so far been reported in the literature have been based on operational amplifiers working in transimpedance configurations. Taking into consideration that QEPAS sensors are based on quartz tuning forks, and that quartz has a relatively high voltage constant and relatively low charge constant, it seems that a transimpedance amplifier is not an optimal solution. This paper describes the design of a quartz QEPAS sensor preamplifier, implemented with voltage amplifier configuration. Discussion of an electrical model of the circuit and preliminary measurements are presented. Both theoretical analysis and experiments show that use of the voltage configuration allows for a substantial increase of the output signal in comparison to the transimpedance circuit with the same tuning fork working in identical conditions. Assuming that the sensitivity of the QEPAS technique depends directly on the properties of the preamplifier, use of the voltage amplifier configuration should result in an increase of QEPAS sensitivity by one to two orders of magnitude.

A High Sensitivity Preamplifier for Quartz Tuning Forks in QEPAS (Quartz Enhanced PhotoAcoustic Spectroscopy) Applications.

Science.gov (United States)

Starecki, Tomasz; Wieczorek, Piotr Z

2017-11-03

All the preamplifiers dedicated for Quartz Enhanced PhotoAcoustic Spectroscopy (QEPAS) applications that have so far been reported in the literature have been based on operational amplifiers working in transimpedance configurations. Taking into consideration that QEPAS sensors are based on quartz tuning forks, and that quartz has a relatively high voltage constant and relatively low charge constant, it seems that a transimpedance amplifier is not an optimal solution. This paper describes the design of a quartz QEPAS sensor preamplifier, implemented with voltage amplifier configuration. Discussion of an electrical model of the circuit and preliminary measurements are presented. Both theoretical analysis and experiments show that use of the voltage configuration allows for a substantial increase of the output signal in comparison to the transimpedance circuit with the same tuning fork working in identical conditions. Assuming that the sensitivity of the QEPAS technique depends directly on the properties of the preamplifier, use of the voltage amplifier configuration should result in an increase of QEPAS sensitivity by one to two orders of magnitude.

Electrochemical maps and movies of the hydrogen evolution reaction on natural crystals of molybdenite (MoS2): basal vs. edge plane activity.

Science.gov (United States)

Bentley, Cameron L; Kang, Minkyung; Maddar, Faduma M; Li, Fengwang; Walker, Marc; Zhang, Jie; Unwin, Patrick R

2017-09-01

Two dimensional (2D) semiconductor materials, such as molybdenum disulfide (MoS 2 ) have attracted considerable interest in a range of chemical and electrochemical applications, for example, as an abundant and low-cost alternative electrocatalyst to platinum for the hydrogen evolution reaction (HER). While it has been proposed that the edge plane of MoS 2 possesses high catalytic activity for the HER relative to the "catalytically inert" basal plane, this conclusion has been drawn mainly from macroscale electrochemical (voltammetric) measurements, which reflect the "average" electrocatalytic behavior of complex electrode ensembles. In this work, we report the first spatially-resolved measurements of HER activity on natural crystals of molybdenite, achieved using voltammetric scanning electrochemical cell microscopy (SECCM), whereby pixel-resolved linear-sweep voltammogram (LSV) measurements have allowed the HER to be visualized at multiple different potentials to construct electrochemical flux movies with nanoscale resolution. Key features of the SECCM technique are that characteristic surface sites can be targeted and analyzed in detail and, further, that the electrocatalyst area is known with good precision (in contrast to many macroscale measurements on supported catalysts). Through correlation of the local voltammetric response with information from scanning electron microscopy (SEM) and atomic force microscopy (AFM) in a multi-microscopy approach , it is demonstrated unequivocally that while the basal plane of bulk MoS 2 (2H crystal phase) possesses significant activity, the HER is greatly facilitated at the edge plane ( e.g. , surface defects such as steps, edges or crevices). Semi-quantitative treatment of the voltammetric data reveals that the HER at the basal plane of MoS 2 has a Tafel slope and exchange current density ( J 0 ) of ∼120 mV per decade and 2.5 × 10 -6 A cm -2 (comparable to polycrystalline Co, Ni, Cu and Au), respectively, while the edge

Quartz exposure and increased respiratory symptoms among coal ...

African Journals Online (AJOL)

Quartz has been an inevitable composition of different type of coal mined. The quartz exposures among coalmine workers has been attributed to activities such as cutting the adjacent rock, the roof, the floor and the intrusions. Objective: The aim of the study is to determine the associations between quartz exposures and ...

Microwave GaAs Integrated Circuits On Quartz Substrates

Science.gov (United States)

Siegel, Peter H.; Mehdi, Imran; Wilson, Barbara

1994-01-01

Integrated circuits for use in detecting electromagnetic radiation at millimeter and submillimeter wavelengths constructed by bonding GaAs-based integrated circuits onto quartz-substrate-based stripline circuits. Approach offers combined advantages of high-speed semiconductor active devices made only on epitaxially deposited GaAs substrates with low-dielectric-loss, mechanically rugged quartz substrates. Other potential applications include integration of antenna elements with active devices, using carrier substrates other than quartz to meet particular requirements using lifted-off GaAs layer in membrane configuration with quartz substrate supporting edges only, and using lift-off technique to fabricate ultrathin discrete devices diced separately and inserted into predefined larger circuits. In different device concept, quartz substrate utilized as transparent support for GaAs devices excited from back side by optical radiation.

Timescales and conditions of crystallization in the Pokai and Chimpanzee Ignimbrites, Taupo Volcanic Zone, New Zealand

Science.gov (United States)

Connor, M.; Gualda, G. A.; Gravley, D. M.

2013-12-01

Silicic magmas give rise to explosive eruptions that are both of scientific and societal interest. The central Taupo Volcanic Zone in New Zealand has been volcanically active for 2 Ma and represents the most active volcanic area in the world today. Particularly intense volcanic activity took place as part of a flare-up event that occurred from ~340 to ~240 ka, when 7 large ignimbrite eruptions took place, as well as many smaller eruptions, which erupted a total of at least 3000 km3 of magma. This project seeks to identify the conditions and timescales over which magma bodies that gave rise to these ignimbrite eruptions evolved. We aim to understand how much of the tens of thousands of years between successive eruptions were characterized by the presence of large bodies of silicic magma within the crust, as well the magma distribution within the crust during those times. We focus on the Chimpanzee and Pokai ignimbrites, which together erupted ~150 km3 of magma. The Pokai ignimbrite erupted at ~275 ka, while the Chimpanzee ignimbrite (undated) erupted between ~320 and 275 ka. Pumice clasts from the Chimpanzee and Pokai ignimbrite were collected in the field. Pumice bulk densities were measured using a submersion technique. Quartz and plagioclase crystals were extracted through a crushing, sieving, and winnowing procedure. Whole crystals were hand-picked under a conventional microscope, mounted on epoxy, and polished to expose grain interiors. Grain mounts were analyzed under an SEM using back-scattered electron, cathodoluminescence (CL), and energy-dispersive x-ray (EDX) imaging. Bulk-densities vary from 0.42 to 0.81 g/cm3 for Pokai and between 0.52 and 0.64 g/cm3 for Chimpanzee pumice clasts. Plagioclase is the dominant crystal phase in both units. Several plagioclase crystals have inclusions of orthopyroxene, ilmenite, magnetite, and zircon, which in some cases form clusters. Quartz is rare but is present in pumice from both deposits. Both plagioclase and quartz

Characterization of color centers in quartz induced by gamma irradiation

International Nuclear Information System (INIS)

Guttler, Rainer A.S.

2009-01-01

The availability of gamma ray irradiators in Brazil increased the possibilities of treatments of gemstones for color enhancements. One of the minerals with a very high potential of these treatments is quartz, a very widespread mineral with much colored commercial varieties. Quartz occurs in Brazil mainly in two geological environments, called pegmatitic and hydrothermal. The detailed mechanism of color center formation of these two types of quartz will be investigated by spectroscopic and chemical analysis. Until yet, it can be shown that due to chemical differences of the nature of mineral forming fluids, the two types behave differently. All quartzes contain mainly traces of Iron, Aluminum, Lithium and some amounts of Water. The quartz of hydrothermal origin incorporated much structurally bound water, and despite some similarities with the chemical composition of pegmatitic quartz, this high water content is the reason for the formation of Silanol radicals, giving the green color to the quartz. The main difference in chemical composition of pegmatitic quartz is the presence of higher amounts of Al and Li , responsible for the brownish and yellowish colors formed by irradiation. Since each pegmatite is different, the quartz will behave differently. This explains the formation of the famous 'Green Gold' of quartz from Sao Jose da Safira , and the more yellowish, Citrine type, color of quartz from the Coluna deposit, near Itamarandiba, Minas Gerais. (author)

Characterization of color centers in quartz induced by gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Guttler, Rainer A.S., E-mail: rainersg@usp.b [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias; Enokihara, Cyro T.; Rela, Paulo R., E-mail: prela@ipen.b, E-mail: cteiti@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2009-07-01

The availability of gamma ray irradiators in Brazil increased the possibilities of treatments of gemstones for color enhancements. One of the minerals with a very high potential of these treatments is quartz, a very widespread mineral with much colored commercial varieties. Quartz occurs in Brazil mainly in two geological environments, called pegmatitic and hydrothermal. The detailed mechanism of color center formation of these two types of quartz will be investigated by spectroscopic and chemical analysis. Until yet, it can be shown that due to chemical differences of the nature of mineral forming fluids, the two types behave differently. All quartzes contain mainly traces of Iron, Aluminum, Lithium and some amounts of Water. The quartz of hydrothermal origin incorporated much structurally bound water, and despite some similarities with the chemical composition of pegmatitic quartz, this high water content is the reason for the formation of Silanol radicals, giving the green color to the quartz. The main difference in chemical composition of pegmatitic quartz is the presence of higher amounts of Al and Li , responsible for the brownish and yellowish colors formed by irradiation. Since each pegmatite is different, the quartz will behave differently. This explains the formation of the famous 'Green Gold' of quartz from Sao Jose da Safira , and the more yellowish, Citrine type, color of quartz from the Coluna deposit, near Itamarandiba, Minas Gerais. (author)

Surface complexation modelling: Experiments on sorption of nickel on quartz, goethite and kaolinite and preliminary tests on sorption of thorium on quartz

Energy Technology Data Exchange (ETDEWEB)

Puukko, E.; Hakanen, M. [Univ. of Helsinki (Finland). Dept. of Chemistry. Lab. of Radiochemistry

1997-09-01

The aim of the work was to study the sorption behaviour of Ni on quartz, goethite and kaolinite at different pH levels and in different electrolyte solutions of different strength. In addition preliminary experiments were made to study the sorption of thorium on quartz. The MUS quartz and Nilsiae quartz were analysed for MnO{sub 2} by neutron activation analysis (NAA) and the experimental results were modelled with the HYDRAQL computer model. 9 refs.

Geology and geochemistry of giant quartz veins from the ...

Indian Academy of Sciences (India)

Numerous younger thin quartz veins with somewhat similar orientation cut across the giant quartz .... Angular fragments of quartz are set in ... places along grain boundaries. ... Oxide values are in wt%, and trace element concentrations are.

Electropolymerized Molecularly Imprinted Polypyrrole Film for Sensing of Clofibric Acid

OpenAIRE

Schweiger, Bianca; Kim, Jungtae; Kim, Young; Ulbricht, Mathias

2015-01-01

Piezoelectric quartz crystals and analogous gold substrates were electrochemically coated with molecularly imprinted polypyrrole films for pulsed amperometric detection (PAD) of clofibric acid, a metabolite of clofibrate. Cyclic voltammetry data obtained during polymerization and deposited weight estimations revealed a decrease of the polymerization rate with increasing clofibric acid concentration. XPS measurements indicated that clofibric acid could be removed after imprinting with an aqueo...

Anisotropic viscoelastic properties of quartz and quartzite in the vicinity of the α- β phase transition

Science.gov (United States)

Klumbach, Steffen; Schilling, Frank R.

2017-10-01

In this study we performed high-temperature, dynamic (i.e. sinusoidal), three-point bending experiments of quartz single crystals and quartzite samples within the frequency range of seismic surveys (i.e. 0.1-20 Hz). At constant temperature close to the α- β phase transition we observed a unique complex elastic behaviour of both quartz and quartzite. We find a frequency dependence of the complex Young's modulus of α-quartz, including a dissipation maximum at ≈1 Hz supposedly related to the formation and variation of Dauphiné twin domains. Based on our experimental results for different crystallographic directions and additional modelling, we are able to describe the complex Young's modulus of quartz at its α- β phase transition in a 3D diagram. We derive a frequency-dependent elasticity tensor, using a three-element equivalent circuit, composed of two springs E 1 and E 2 as well as a dashpot η. E 1 and η are connected parallel to each other, E 2 is added in series. Compliance coefficients yield ( S 11) E 1 = 572 GPa, E 2 = 70.0 GPa, η = 64.6 GPa·s, ( S 33) E 1 = 127 GPa, E 2 = 52.1 GPa, η = 22.9 GPa·s, ( S 44) E 1 = 204 GPa, E 2 = 37.5 GPa, η = 26.4 GPa·s, ( S 12) E 1 = 612 GPa, E 2 = 106.7 GPa, η = 78.5 GPa·s, ( S 13) E 1 = 1546 GPa, E 2 = 284 GPa, η = 200 GPa·s; S 14 ≈-0.0024 GPa-1. We use the derived direction-dependent coefficients to predict the frequency-dependent complex elastic properties of isotropic polycrystalline quartz. These predictions agree well with the experimental results of the investigated quartzite. Finally, we explore the potential of using the anomalous frequency-dependent complex elastic properties of quartz at the α- β phase transition that we observed as an in situ temperature probe for seismic studies of the Earth's continental crust.

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...... dispersion in the distribution; the only existing way to test this assumption is using independent age control. Here we suggest a new approach to this question, based on the differential bleaching rates of quartz and feldspar luminescence signals. We first present data that confirm the differences...... 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...

Single Crystals Grown Under Unconstrained Conditions

Science.gov (United States)

Sunagawa, Ichiro

Based on detailed investigations on morphology (evolution and variation in external forms), surface microtopography of crystal faces (spirals and etch figures), internal morphology (growth sectors, growth banding and associated impurity partitioning) and perfection (dislocations and other lattice defects) in single crystals, we can deduce how and by what mechanism the crystal grew and experienced fluctuation in growth parameters through its growth and post-growth history under unconstrained condition. The information is useful not only in finding appropriate way to growing highly perfect and homogeneous single crystals, but also in deciphering letters sent from the depth of the Earth and the Space. It is also useful in discriminating synthetic from natural gemstones. In this chapter, available methods to obtain molecular information are briefly summarized, and actual examples to demonstrate the importance of this type of investigations are selected from both natural minerals (diamond, quartz, hematite, corundum, beryl, phlogopite) and synthetic crystals (SiC, diamond, corundum, beryl).

Sensing molecular properties by ATR-SPP Raman spectroscopy on electrochemically structured sensor chips

International Nuclear Information System (INIS)

Zerulla, D.; Isfort, G.; Koelbach, M.; Otto, A.; Schierbaum, K.

2003-01-01

The use of electrochemically structured Al surfaces as sensor arrays for combinatorial chemistry and its detection via microscopic laser techniques from very small volumes has been explored. The methodology is based on three different techniques which will be discussed separately: firstly, attenuated total reflection (ATR) is used in connection with surface-plasmon-polariton (SPP) excitation. A thin Al layer, evaporated on sapphire or quartz and covered with a naturally grown oxide layer, provides an optimum enhancement and confinement of the electrical field close to the surface. This is revealed by calculations and experimental data. Secondly, a Raman microscope is applied, enabling chemical spot analysis in the visible and UV range with a lateral resolution close to the diffraction limit. Finally, its application to investigate electrochemically structured Al films is discussed

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

International Nuclear Information System (INIS)

Nur, N.; Yeğingil, Z.; Topaksu, M.; Kurt, K.; Doğan, T.; Sarıgül, N.; Yüksel, M.; Altunal, V.; Özdemir, A.; Güçkan, V.; Günay, I.

2015-01-01

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 90 Sr/ 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, exhibit dose�

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

Characterization of the optical grade synthetic quartz by X-ray topography

International Nuclear Information System (INIS)

Tanaka, Marcos S.; Suzuki, Carlos K.; Iwasaki, Fumiko

1996-01-01

The first initiative to develop a technology to grow the optical grade synthetic quartz in our country has been conducted by the UNICAMP - JICA - ABC Crystals collaboration. This research shows that the solid inclusions concentrations is practically inexistent, less than 0.03 incl/cm 3 , what satisfy the international standard requirements. On the other hand, the characterization studies by X-ray topography enabled us to estimate the dislocation line density of order of 1200 lines/cm 2 . This value is higher than to the usual international standard requirements. From this study, we obtained a full knowledge of defects origin, where the optimization process could be done by using seeds with superior quality. (author)

Red and blue colouration of thermoluminescence from natural quartz sands

Energy Technology Data Exchange (ETDEWEB)

Hashimoto, T; Hayashi, Y; Koyanagi, A; Yokosaka, K; Kimura, K

1986-01-01

Quartz extracts, from a pegmatite rock, volcanic ashes and beach sands, were exposed to X-rays or gamma-rays upto 8.8kGy. The irradiated sands were observed through a thermoluminescence colour image technique (abbreviated to TLCI by the authors) using highly sensitive colour photographic system. The quartz sands from volcanic ash layers, containing ..beta..-quartz (mineralized at high temperature), always indicate a red TLCI, whereas the quartz rocks from pegmatite origin and granite strata, containing ..cap alpha..-quartz (mineralized at low temperature), gave a typical blue TLCI, being consistent with the well known quartz TL colour. Quartz fractions from the beach sands showed a mixture of both red and blue TLCI, probably reflecting the respective mixtures of ..beta..-(in their origin) and ..cap alpha..-quartz fractions along the riverside area. The search using X-ray diffractometry and instrumental neutron activation analysis proved that the cause of distinctly different colourations was attributable to the impurity atoms: light rare earth elements (Eu and/or Sm) bringing on red TLCI, while structural defects yielding the blue TLCI).

TL response to quartz and aluminum oxide grain for α-irradiation

International Nuclear Information System (INIS)

Pan Baolin; Wei Mingjian; Li Dongxu; Liu Zhaowen; Liu Chao; Zhao Shiyuan

2009-01-01

Thermoluminescence (TL) response for an α-ray irradiation system ( 241 Am) was examined with quartz grains of 11-40 μm. Quartz grains of different sizes, i.e. 137 Cs), before they were irradiated to different doses by the α-ray irradiation system. TL response to the quartz grain samples was measured. TL response of the quartz grains smaller than 4 μm and 11-40 μm to α-ray irradiation is the best, as the α-rays cannot penetrate quartz larger than 40 μm. The TL response characteristic is related with quartz grain surface area. TL responses to α-irradiation of 11-40 μm quartz and aluminum oxide grains were compared. The α-irradiation TL response of aluminum oxide (330 degree C) is better than the quartz (375 degree C). (authors)

Hydrothermal Growth of Polyscale Crystals

Science.gov (United States)

Byrappa, Kullaiah

In this chapter, the importance of the hydrothermal technique for growth of polyscale crystals is discussed with reference to its efficiency in synthesizing high-quality crystals of various sizes for modern technological applications. The historical development of the hydrothermal technique is briefly discussed, to show its evolution over time. Also some of the important types of apparatus used in routine hydrothermal research, including the continuous production of nanosize crystals, are discussed. The latest trends in the hydrothermal growth of crystals, such as thermodynamic modeling and understanding of the solution chemistry, are elucidated with appropriate examples. The growth of some selected bulk, fine, and nanosized crystals of current technological significance, such as quartz, aluminum and gallium berlinites, calcite, gemstones, rare-earth vanadates, electroceramic titanates, and carbon polymorphs, is discussed in detail. Future trends in the hydrothermal technique, required to meet the challenges of fast-growing demand for materials in various technological fields, are described. At the end of this chapter, an Appendix 18.A containing a more or less complete list of the characteristic families of crystals synthesized by the hydrothermal technique is given with the solvent and pressure-temperature (PT) conditions used in their synthesis.

Kinetics of the stress induced phase transition in quartz by real-time neutron scattering

International Nuclear Information System (INIS)

Gibhardt, H.; Eckold, G.; Guethoff, F.

1999-01-01

Complete text of publication follows. The stability regime of the incommensurate phase of quartz is influenced by uniaxial stress. Hence, the phase transition can be induced under isothermal conditions by the application of external mechanical forces. Using real-time neutron scattering the time evolution of structural changes is investigated id detail during stress variations. The time dependent behaviour of the satellite reflection is compared with that one of the fundamental Bragg reflection which - via primary extinction - gives information about the perfection of the crystal. On increasing stress the perfection of the lattice is destroyed immediately while the modulated structure is built up with a delay of about 1 s. Decreasing the stress leads to a reverse behaviour. Moreover, there is evidence that under periodical load residual non-relaxed strain fields survive leading to a different temperature dependence as compared to static conditions. This finding is compatible with pronounced hysteresis effects observed under cycling stress. It is argued that these residual strains are associated with non-relaxed topological 4-line defects, that drive the structural changes in quartz (1). (author)

Radiation resistivity of quartz core fiber, 3

International Nuclear Information System (INIS)

Gozen, Toshikazu; Suzuki, Toshiya; Hayashi, Tokuji; Tanaka, Hiroyuki; Okamoto, Shinichi.

1985-01-01

Radiation resistance characteristics were evaluated for a multi-mode quartz core fiber in low temperature region together with photobleaching effect depending on the incident light power and dependency on the wavelength of measuring rays. This report describes the results of the abovementioned items and the next step study of trial manufacturing of a pure-quartz single-mode fiber for the employment of longer wavelength rays and greater capacity in light transmission communication system. Quartz core fiber specimens were irradiated by 60 Co γ-ray source at -55 deg C to 80 deg C in a constant temperature bath and light transmission loss was determined under irradiation conditions. Low temperature characteristics were superior in an MRT (modified rod-in tube) pure quartz fiber prepared by the plasma method as compared to VAD quartz and Ge-GI fibers. The MRT fiber showed better quality than the Ge-GI fiber also in the photobleaching effect examination. As for the wavelength dependency, light transmission loss of the MRT fiber was less than that of the Ge-GI fiber. The MRT fiber also showed a superior quality in the wide range of irradiation temperatures. Based on the above-mentioned understandings, a pure-quartz single-mode fiber of both BF 3 -doped and F-doped cladding types were developed for longer wavelengths uses. The fibers could attain low light transmission loss of less than 1.0 dB/km at 1.30 μm of wavelength. At the standpoint of radiation resistivity, the BF 3 -doped fiber was found superior. (Takagi, S.)

Analysis Of The Underpotential Deposition Of Cadmium On Copper

Directory of Open Access Journals (Sweden)

Kowalik R.

2015-09-01

Full Text Available In this study the process of deposition of cadmium on polycrystalline copper electrode in sulfate solution was investigated. The process of underpotential and bulk deposition was analyzed by classical electrochemical method: cyclic voltammetry(CV, anodic stripping voltammetry(ASV and electrochemical quartz crystal microbalance(EQCM. The obtained results were compared with electrochemical impedance spectroscopy(EIS measurements. CV, EQCM and EIS results suggest that the UPD of cadmium starts below potential −0.4 V vs Ag/AgCl. Additionally the stripping analysis indicates the formation of cadmium monolayer with different density of deposited atoms depending on the applied potential. The transition from UPD to bulk deposition occurs below potential −0,7 V.

Low-power crystal and MEMS oscillators the experience of watch developments

CERN Document Server

Eric Vittoz

2010-01-01

Electronic oscillators using an electromechanical device as a frequency reference are irreplaceable components of systems-on-chip for time-keeping, carrier frequency generation and digital clock generation. With their excellent frequency stability and very large quality factor Q, quartz crystal resonators have been the dominant solution for more than 70 years. But new possibilities are now offered by micro-electro-mechanical (MEM) resonators, that have a qualitatively identical equivalent electrical circuit. Low-Power Crystal and MEMS Oscillators concentrates on the analysis and design of the most important schemes of integrated oscillator circuits. It explains how these circuits can be optimized by best exploiting the very high Q of the resonator to achieve the minimum power consumption compatible with the requirements on frequency stability and phase noise. The author has 40 years of experience in designing very low-power, high-performance quartz oscillators for watches and other battery operated systems an...

Asymmetric adsorption of alanine by quartz powder from ethanol solution

Energy Technology Data Exchange (ETDEWEB)

Furuyama, Shozo; Sawada, Michio; Hachiya, Kinji; Morimoto, Tetsuo (Okayama Univ. (Japan). Faculty of Science)

1982-11-01

The asymmetric adsorption of the racemic alanine by the optically active quartz from ethanol solution at 8/sup 0/C was studied by the /sup 14/C-tracer method and the newly developed /sup 14/C-tracer ninhydrin-colorimetry combination method. The preferential adsorption of L-alanine by levorotatory quartz (l-quartz) and D-alanine by dextrorotatory quartz (d-quartz) was confirmed. The asymmetric adsorptivity (Asub(s)) falls in the range of 1.1 - 1.3, which is comparable with the value determined at - 80/sup 0/C in the previous paper. The effects of water content in the ethanol solution and of the adsorption temperature upon the adsorption affinity of alanine to quartz were also measured. The cause for the asymmetric adsorption is discussed from the crystallographic point of view.

Electrochemical synthesis of mesoporous Pt-Au binary alloys with tunable compositions for enhancement of electrochemical performance.

Science.gov (United States)

Yamauchi, Yusuke; Tonegawa, Akihisa; Komatsu, Masaki; Wang, Hongjing; Wang, Liang; Nemoto, Yoshihiro; Suzuki, Norihiro; Kuroda, Kazuyuki

2012-03-21

Mesoporous Pt-Au binary alloys were electrochemically synthesized from lyotropic liquid crystals (LLCs) containing corresponding metal species. Two-dimensional exagonally ordered LLC templates were prepared on conductive substrates from diluted surfactant solutions including water, a nonionic surfactant, ethanol, and metal species by drop-coating. Electrochemical synthesis using such LLC templates enabled the preparation of ordered mesoporous Pt-Au binary alloys without phase segregation. The framework composition in the mesoporous Pt-Au alloy was controlled simply by changing the compositional ratios in the precursor solution. Mesoporous Pt-Au alloys with low Au content exhibited well-ordered 2D hexagonal mesostructures, reflecting those of the original templates. With increasing Au content, however, the mesostructural order gradually decreased, thereby reducing the electrochemically active surface area. Wide-angle X-ray diffraction profiles, X-ray photoelectron spectra, and elemental mapping showed that both Pt and Au were atomically distributed in the frameworks. The electrochemical stability of mesoporous Pt-Au alloys toward methanol oxidation was highly improved relative to that of nonporous Pt and mesoporous Pt films, suggesting that mesoporous Pt-Au alloy films are potentially applicable as electrocatalysts for direct methanol fuel cells. Also, mesoporous Pt-Au alloy electrodes showed a highly sensitive amperometric response for glucose molecules, which will be useful in next-generation enzyme-free glucose sensors.

Circular patterns of calcium oxalate monohydrate induced by defective Langmuir-Blodgett film on quartz substrates

Energy Technology Data Exchange (ETDEWEB)

He Jieyu [Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China); Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China); Ouyang Jianming [Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China); Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China)], E-mail: toyjm@jnu.edu.cn

2009-01-01

The defective Langmuir-Blodgett (LB) film of dipalmitoylphosphatidylcholine (DPPC) on quartz injured by potassium oxalate (K{sub 2}C{sub 2}O{sub 4}) was used as a model system to induce growth of calcium oxalate crystals. Atomic force microscopy (AFM) indicated that circular defective domains with a diameter of 1-200 {mu}m existed in the LB film. Scanning electron microscopy (SEM) showed circular patterns of aggregated calcium oxalate monohydrate (COM) crystallites were induced by these defective domains. It was ascribed to that the interaction between the negatively-charged oxalate ions and the phosphatidyl groups in DPPC headgroups makes the phospholipid molecules rearranged and exist in an out-of-order state in the LB film, especially at the boundaries of liquid-condensed (LC)/liquid-expanded (LE) phases, which provide much more nucleating sites for COM crystals.

Growth of tourmaline single crystals containing transition metal elements in hydrothermal solutions

Science.gov (United States)

Setkova, Tatiana; Shapovalov, Yury; Balitsky, Vladimir

2011-03-01

Interest in the growth of tourmaline single crystals is based on the promising piezoelectric and pyroelectric properties of this material compared to quartz crystals currently in use. Moreover, synthetic tourmaline can be used as a substitute for the natural stone in the jewelry industry similar to other synthetic analogues of gemstones. Single crystals of colored Co-, Ni-, Fe-, (Ni,Cr)-, (Ni,Fe)-, and (Co,Ni,Cr)-containing tourmalines with concentration of transition metal elements up to 16 wt% on a seed have been grown from complex boron-containing hydrothermal solutions at a range of temperatures 400-750 °C and pressures 100 MPa. Experiments were conducted under conditions of a thermal gradient in titanium and chromium-nickel autoclaves. Tourmaline growth on a seed crystal occurs only if separate tourmaline-forming components (monocrystalline corundum and quartz bars) are used as charge. All tourmalines specified above grow in analogous (+) direction of the optical axis with a speed of 0.05 mm/day by faces of the trigonal pyramid, except tourmalines containing chromium. They grow in analogous (+0001) direction with a speed 0.05 mm/day, and in antilogous (-0001) direction with a speed of 0.01 mm/day by faces of the trigonal pyramid and in prism direction with a speed of 0.001 mm/day. Along with the large single crystals, a great amount of finest (30-150 μm in size) tourmaline crystals was formed during the runs by spontaneous nucleation both on the surface of the seed crystals and in the charge.

Cosmic ray production rates of Be-10 and Al-26 in quartz from glacially polished rocks

Science.gov (United States)

Nishiizumi, K.; Kohl, C. P.; Winterer, E. L.; Klein, J.; Middleton, R.

1989-01-01

The concentrations of Be-10 and Al-26 in quartz crystals extracted from glacially polished granitic surfaces from the Sierra Nevada range are studied. These surfaces are identified with the glacial advance during the Tioga period about 11,000 yr ago. The measurements yield the most accurate estimates to date for the absolute production rates of three nuclides in SiO2 due to cosmic ray nucleons and muons for geomagnetic latitudes 43.8-44.6 N and altitudes 2.1-3.6 km.

Composition of coarse-grained magnetite from pegmatite dikes related to plutons of quartz monzonite in the Jabal Lababa area, Kingdom of Saudi Arabia

Science.gov (United States)

Overstreet, William C.; Mousa, Hassan; Matzko, John J.

1985-01-01

Crystals of magnetite as large as 30 mm long and 7 mm thick are locally present in quartz-rich zones of interior and exterior pegmatite dikes related to plutons of quartz monzonite in the Jabal Lababa area. Niobium, tin, and yttrium are strongly enriched in six specimens of magnetite from interior pegmatite dikes in a small pluton where these elements form geochemical anomalies in nonmagnetic heavy-mineral concentrates from wadi sediment. Less abundant anomalous elements in the magnetite are molybdenum, lead, and zirconium, which also tend to be present in anomalous amounts in the nonmagnetic concentrates from the niobium-bearing pluton. The most anomalous trace element in the magnetite is zinc, which is at least 10 times as abundant as it is in the quartz monzonite plutons or in the nonmagnetic concentrates. The capacity of magnetite to scavenge molybdenum, zinc, niobium, lead, tin, yttrium, and zirconium suggests the possible utility of magnetite as a geochemical sample medium.

Symmetry and physical properties of crystals

CERN Document Server

Malgrange, Cécile; Schlenker, Michel

2014-01-01

Crystals are everywhere, from natural crystals (minerals) through the semiconductors and magnetic materials in electronic devices and computers or piezoelectric resonators at the heart of our quartz watches to electro-optical devices. Understanding them in depth is essential both for pure research and for their applications. This book provides a clear, thorough presentation of their symmetry, both at the microscopic space-group level and the macroscopic point-group level. The implications of the symmetry of crystals for their physical properties are then presented, together with their mathematical description in terms of tensors. The conditions on the symmetry of a crystal for a given property to exist then become clear, as does the symmetry of the property. The geometrical representation of tensor quantities or properties is presented, and its use in determining important relationships emphasized. An original feature of this book is that most chapters include exercises with complete solutions. This all...

The mineralogy and geochemistry of quartz-tourmaline schlieren in the granites of the Primorsky Complex, Western Baikal Region

Science.gov (United States)

Savel'eva, V. B.; Bazarova, E. P.; Kanakin, S. V.

2014-12-01

Quartz-tourmaline schlieren have been found within rapakivi-like granites of the Early Proterozoic Primorsky Complex in the Western Baikal Region. These rocks are biotite leucogranites with normal alkalinity (A/CNK = 1.00-1.04); a high iron mole fraction (92-95%); a K2O/Na2O value of about 2.0; relatively high F, Li, Rb, Cs, Sn, Pb, Th, and U contents; and low Ba, Sr, Eu, Zn, Sc, and V contents. The schlieren composed of quartz and tourmaline with relics of feldspar also contain fluorite, rare muscovite, chlorite, and accessory rutile, ilmenite, zircon, monazite, xenotime, and bastnäsite. B2O3 and F contents in the schlieren are 2.29-2.63 and 0.30-0.47 wt %, respectively. Fe2O3 (4.8-5.4 wt %), F, and H2O contents are higher in these schlieren than in the host granite, while SiO2, CaO, Na2O, K2O, and P2O5 contents are lower than in host rocks. K2O/Na2O values decrease in the schlieren down to 0.4. Enrichment of the schlieren in Fe and other ore elements (Zn, Co, Cu, Sn, etc.), together with B, F, H2O, and Na, suggests that they crystallized from fluid-saturated melt segregated from aluminosilicate melt in the apical part of a shallow-seated intrusion. The formation of tourmaline may be related to the interaction of the fluid with feldspars in the crystallizing granites; it was accompanied by a separation of fluid F-CO2. Quartz precipitated at the next stage, due to the acidic character of the aqueous fluid. In general, the relationships of minerals in the schlieren indicate distinct fractionation of LREE, HREE, and Y in the fluid-saturated melt.

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...

Mucoadhesion vs mucus permeability of thiolated chitosan polymers and their resulting nanoparticles using a quartz crystal microbalance with dissipation (QCM-D).

Science.gov (United States)

Oh, Sejin; Borrós, Salvador

2016-11-01

The aim of this present study was to evaluate the combination properties between mucoadhesion/mucus permeability of thiolated chitosans (TC) and their resulting nanoparticles using a quartz crystal microbalance with dissipation (QCM-D). The QCM-D experiments were conducted at pH 4 or 6.8 to assess the interaction between thiolated polymers, with low (TCL), medium (TCM) and high (TCH) contents of free thiol groups, and native porcine gastric mucin (NPGM). TCL was chosen for further carriers as it showed higher permeability into the NPGM layer compared to TCM and TCH. In this study, we describe a formulation of a novel carrier comprised by positively charged TCL, negatively charged DNA and degradable oligopeptide-modified poly(β-amino ester)s (PBAEs), which were employed in order to approach for tuning particle size and surface charge of complexes. TCL/PBAE complexes with or without DNA were characterized using dynamic light scattering. Mechanism of adsorption or permeation of the TCL/PBAE/DNA complexes into the NPGM barrier was investigated with QCM-D, which is a highly sensitive technique for studying nanomechanical (viscoelastic) changes of the substrates. This work might provide that the QCM-D technique would be a promising method to monitor the dynamic behaviour between complexes and NPGM. Copyright © 2016 Elsevier B.V. All rights reserved.

Highly selective detection of single-nucleotide polymorphisms using a quartz crystal microbalance biosensor based on the toehold-mediated strand displacement reaction.

Science.gov (United States)

Wang, Dingzhong; Tang, Wei; Wu, Xiaojie; Wang, Xinyi; Chen, Gengjia; Chen, Qiang; Li, Na; Liu, Feng

2012-08-21

Toehold-mediated strand displacement reaction (SDR) is first introduced to develop a simple quartz crystal microbalance (QCM) biosensor without an enzyme or label at normal temperature for highly selective and sensitive detection of single-nucleotide polymorphism (SNP) in the p53 tumor suppressor gene. A hairpin capture probe with an external toehold is designed and immobilized on the gold electrode surface of QCM. A successive SDR is initiated by the target sequence hybridization with the toehold domain and ends with the unfolding of the capture probe. Finally, the open-loop capture probe hybridizes with the streptavidin-coupled reporter probe as an efficient mass amplifier to enhance the QCM signal. The proposed biosensor displays remarkable specificity to target the p53 gene fragment against single-base mutant sequences (e.g., the largest discrimination factor is 63 to C-C mismatch) and high sensitivity with the detection limit of 0.3 nM at 20 °C. As the crucial component of the fabricated biosensor for providing the high discrimination capability, the design rationale of the capture probe is further verified by fluorescence sensing and atomic force microscopy imaging. Additionally, a recovery of 84.1% is obtained when detecting the target sequence in spiked HeLa cells lysate, demonstrating the feasibility of employing this biosensor in detecting SNPs in biological samples.

Quartz reserves in Brazil: planning and photovoltaic industry; Reservas de quartzo no Brasil: planejamento e Industria fotovoltaica

Energy Technology Data Exchange (ETDEWEB)

Marczewski, Breitner; Gonzalez, Mariana Pedrosa; Oliveira, Sergio H.F. [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil). Dept. de Energia], emails: mariana.gonzalez@ufabc.edu.br, sergio.oliveira@ufabc.edu.br

2010-07-01

The goal of this research was examine the availability of part of Brazilian quartz resource for the construction of a photovoltaic industry in the country and the possibility to expand your contribution for others markets. The use of renewable alternative sources of energy has been wining more space in the last years, mainly for the photovoltaic technology. The exponential growth of this technology in the world at an average rate of 20% per year allows understand the importance and contribution for the spheres economic, social and environmental. The solar energy it's renewable and doesn't emit greenhouse gases during the generation of electric energy. Favor this background, research and academic development have been investing to make this technology more efficiency and cheap. In this context, Brazil is in a position unique for several aspects, for example, the incidence of high levels of solar radiation during the year, the amount of reserve of quartz, and now, the knowledge to produce this technology in laboratory scale. So, to achieve an hypothetical scenario for the construction of an national industry, to supply this technology not just for the country, as well to Latin America, help the planning and gives credibility for possible actions to be taken. Through the proposal scenario, the result gained was that is at least part of the reserve of quartz, in this case crystal of quartz enough to attend the insertion of 50 MW/year in the country and the possibility to supply international demand without compromise your on future electronic or photovoltaic industry. (author)

Adsorption effectiveness of β-lactoglobulin onto gold surface determined by quartz crystal microbalance.

Science.gov (United States)

Jachimska, B; Świątek, S; Loch, J I; Lewiński, K; Luxbacher, T

2018-06-01

Bovine β-lactoglobulin (LGB) is a transport protein that can bind to its structure hydrophobic bioactive molecules. Due to the lack of toxicity, high stability and pH-dependent molecular binding mechanism, lactoglobulin can be used as a carrier of sparingly soluble drugs. Dynamic light scattering has confirmed LGB's tendency to create oligomeric forms. The hydrodynamic diameter of LGB molecules varies from 4 nm to 6 nm in the pH range of 2-10 and ionic strength I = 0.001-0.15 M, which corresponds to the presence of mono or dimeric LGB forms. The LGB zeta potential varies from 26.5 mV to -33.3 mV for I = 0.01 M and from 13.3 mV to -16 mV for I = 0.15 M in the pH range of 2-10. The isoelectric point is at pH 4.8. As a result of strong surface charge compensation, the maximum effective ionization degree of the LGB molecule is 35% for ionic strength I = 0.01 M and 22% for I = 0.15 M. The effectiveness of adsorption is linked with the properties of the protein, as well as those of the adsorption surface. The functionalization of gold surfaces with β-lactoglobulin (LGB) was studied using a quartz crystal microbalance with energy dissipation monitoring (QCM-D). The effectiveness of LGB adsorption correlates strongly with a charge of gold surface and the zeta potential of the molecule. The greatest value of the adsorbed mass was observed in the pH range in which LGB has a positive zeta potential values, below pH 4.8. This observation shows that electrostatic interactions play a dominant role in LGB adsorption on gold surfaces. Based on the adsorbed mass, protein orientation on gold surfaces was determined. The preferential side-on orientation of LGB molecules observed in the adsorption layer is consistent with the direction of the molecule dipole momentum determined by molecular dynamics simulations of the protein (MD). The use of the QCM-D method also allowed us to determine the effectiveness of adsorption of LGB on gold

Raman and micro-thermometric investigation of the fluid inclusions in quartz in a gold-rich formation from Lepaguare mining district (Honduras, Central America).

Science.gov (United States)

Bersani, D; Salvioli-Mariani, E; Mattioli, M; Menichetti, M; Lottici, P P

2009-08-01

Fluid inclusions in the quartz crystals present in gold-rich veins from central Honduras have been studied by means of micro-thermometry and micro-Raman spectroscopy in order to provide information on the physico-chemical conditions and chemical composition of the mineralizing fluids. The use of a confocal micro-Raman apparatus allowed to obtain information on the fluid composition, in particular on the gas phase, minimizing the contributions of the host matrix to the Raman signal. The samples studied were collected from an area (Lepaguare mining district, Northern-Central Honduras) rich in ore deposits due to the Cenozoic magmatic activity, where the gold and sulphide mineralization is connected with a system of quartz veins (few decimetres thick) occurring in low-grade metamorphic rocks and produced by hydrothermal fluids. The quartz crystals present in the gold-rich veins often contain fluid inclusions. Four types of fluid inclusions have been observed, but their assemblage in the same clusters and fracture systems, as well as their comparable salinity and homogenization data, suggest that they have the same origin. Micro-thermometry and Raman spectroscopy provide a composition of the mineralizing fluids attributable to the system H(2)O-NaCl-KCl-CO(2)-CH(4), with temperature and pressure intervals of 210-413 degrees C and 1050-3850 bar, respectively. These data agree with an epigenetic origin of the gold deposit (depth < 6 km) related to granitoid or granodiorite intrusions associated to orogenic environments.

Crystallic silver amalgam--a novel electrode material.

Science.gov (United States)

Danhel, Ales; Mansfeldova, Vera; Janda, Pavel; Vyskocil, Vlastimil; Barek, Jiri

2011-09-21

A crystallic silver amalgam was found to be a suitable working electrode material for voltammetric determination of electrochemically reducible organic nitro-compounds. Optimum conditions for crystal growth were found, the crystal surface was investigated by atomic force microscopy in tapping mode and single crystals were used for the preparation of quasi-cylindrical single crystal silver amalgam electrode (CAgAE). An electrochemical behavior of this alternative electrode material was investigated in aqueous media by direct current voltammetry, cyclic voltammetry (CV), differential pulse voltammetry (DPV) and adsorptive stripping voltammetry (AdSV) using 4-nitrophenol as a model compound. Applicable potential windows of the CAgAE were found comparable with those obtained at a hanging mercury drop electrode, providing high hydrogen overpotential, and polished silver solid amalgam electrode. Thanks to the smooth single crystal electrode surface, the effect of the passivation is not too pronounced, direct DPV determination of 100 μmol l(-1) of 4-nitrophenol at CAgAEs in 0.2 mol l(-1) acetate buffer pH 4.8 provides a RSD around 1.5% (n = 15). DPV calibration curves of 4-nitrophenol are linear in the whole concentration range 1-100 μmol l(-1) with a limit of quantification of 1.5 μmol l(-1). The attempt to increase sensitivity by application of AdSV was not successful. The mechanism of 4-nitrophenol reduction at CAgAE was investigated by CV.

Microbially induced separation of quartz from hematite using sulfate reducing bacteria.

Science.gov (United States)

Prakasan, M R Sabari; Natarajan, K A

2010-07-01

Cells and metabolic products of Desulfovibrio desulfuricans were successfully used to separate quartz from hematite through environmentally benign microbially induced flotation. Bacterial metabolic products such as extracellular proteins and polysaccharides were isolated from both unadapted and mineral-adapted bacterial metabolite and their basic characteristics were studied in order to get insight into the changes brought about on bioreagents during adaptation. Interaction between bacterial cells and metabolites with minerals like hematite and quartz brought about significant surface-chemical changes on both the minerals. Quartz was rendered more hydrophobic, while hematite became more hydrophilic after biotreatment. The predominance of bacterial polysaccharides on interacted hematite and of proteins on quartz was responsible for the above surface-chemical changes, as attested through adsorption studies. Surface-chemical changes were also observed on bacterial cells after adaptation to the above minerals. Selective separation of quartz from hematite was achieved through interaction with quartz-adapted bacterial cells and metabolite. Mineral-specific proteins secreted by quartz-adapted cells were responsible for conferment of hydrophobicity on quartz resulting in enhanced separation from hematite through flotation. 2010 Elsevier B.V. All rights reserved.

Thermal quenching of thermoluminescence in quartz samples of various origin

International Nuclear Information System (INIS)

Subedi, B.; Oniya, E.; Polymeris, G.S.; Afouxenidis, D.; Tsirliganis, N.C.; Kitis, G.

2011-01-01

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.

Depth of interaction in scintillation crystal by light collimation for the design of open-quotes universal nuclear medicine imagerclose quotes

International Nuclear Information System (INIS)

Bosnjakovic, V.B.

1996-01-01

The detector head for a dual headed open-quotes Universal Nuclear Medicine Imagerclose quotes (UNMI) is designed. It is based on position sensitive (PS) area detectors fitted with a thick (0.75 inches) NaI(Tl) crystal. In order to make it open-quotes universalclose quotes, a means for determining the depth of interaction (DOI) in the crystal is devised. Crystal thickness is divided into two layers, each 3/8 inches thick, by insertion of a thin (0.03 inches) quartz (glass) layer; these layers added to the external lower and upper surfaces of crystal, too, form two internal open-quotes light collimatorclose quotes (LC) channels by their reflectively (specular) polished couplings. These DOI channels, according to the light refraction / reflection law direct the light reflected from quartz layers (as exceeding a critical angle) through NaI(Tl) layers to the external parts of LC system; these are connected via quartz optical cables to the DOI determining PM tubes. DOI electronics including a coincidence circuit, connecting signals from conventional PS and DOI PM tubes arrays, identifies a DOI layer and shifts an, x, y, address to the particular DOI memory stack. The UNMI design is likely to retain spatial resolution of PS detectors - gamma cameras for low energy single photon emitters and to improve spatial resolution in PET studies done by PS detectors fitted with thick NaI crystals, enabling a proper correction for parallax error

Quartz exsolution topotaxy in clinopyroxene from the UHP eclogite of Weihai, China

Science.gov (United States)

Xu, Haijun; Zhang, Junfeng; Zong, Keqing; Liu, Liang

2015-06-01

Abundant oriented silica precipitates of α-quartz (4.0 ± 1.0 vol.%), in part coexisting with calcic amphiboles (topotactic relationships with their host clinopyroxenes. Three types of crystallographic topotactic relationship have been identified between quartz and host clinopyroxene: (1) 52% quartz precipitates share the same orientation for the c-axes with [0001]qz//[001]cpx; (2) 34% quartz precipitates share the same orientation for the a-axes with [11 2 bar0]qz//[001]cpx; and (3) 11% quartz precipitates share the same orientation for the s-planes with (11 2 bar1)qz//(100)cpx. Other quartz axes and planes disperse in large or small girdles around the shared axes or planes. Many quartz rods/needles are elongated parallel to the [001]cpx with the long axes of quartz being either [0001]qz or [11 2 bar0]qz. Amphibole precipitates have also a strong crystallographic relationship with host clinopyroxene, i.e., (100)amp//(100)cpx, [010]amp//[010]cpx, and [001]amp//[001]cpx. These results provide quantitative microstructural evidence supporting an exsolution origin for oriented quartz needles/rods in clinopyroxene and demonstrate that the exsolution of quartz from clinopyroxene occurred within the stability field of α-quartz rather than coesite. The oriented precipitates of α-quartz, in part coexisting with calcic amphiboles, in host clinopyroxene are probably promoted by supercritical fluid or partial melting during the early exhumation of eclogites. Our results suggest that oriented quartz precipitates in clinopyroxene cannot be used as an indisputable UHP-indicator.

Passivation of quartz for halogen-containing light sources

Science.gov (United States)

Falkenstein, Zoran

1999-01-01

Lifetime of halogen containing VUV, UV, visible or IR light sources can be extended by passivating the quartz or glass gas containers with halogens prior to filling the quartz with the halogen and rare gas mixtures used to produce the light.

New Cu (II), Co(II) and Ni(II) complexes of chalcone derivatives: Synthesis, X-ray crystal structure, electrochemical properties and DFT computational studies

Science.gov (United States)

Tabti, Salima; Djedouani, Amel; Aggoun, Djouhra; Warad, Ismail; Rahmouni, Samra; Romdhane, Samir; Fouzi, Hosni

2018-03-01

The reaction of nickel(II), copper(II) and cobalt(II) with 4-hydroxy-3-[(2E)-3-(1H-indol-3-yl)prop-2-enoyl]-6-methyl-2H-pyran-2-one (HL) leads to a series of new complexes: Ni(L)2(NH3), Cu(L)2(DMF)2 and Co(L)2(H2O). The crystal structure of the Cu(L)2(DMF)2 complex have been determined by X-ray diffraction methods. The Cu(II) lying on an inversion centre is coordinated to six oxygen atoms forming an octahedral elongated. Additionally, the electrochemical behavior of the metal complexes were investigated by cyclic voltammetry at a glassy carbon electrode (GC) in CH3CN solutions, showing the quasi-reversible redox process ascribed to the reduction of the MII/MI couples. The X-ray single crystal structure data of the complex was matched excellently with the optimized monomer structure of the desired compound; Hirschfeld surface analysis supported the packed crystal lattice 3D network intermolecular forces. HOMO/LUMO energy level and the global reactivity descriptors quantum parameters are also calculated. The electrophilic and nucleophilic potions in the complex surface are theoretically evaluated by molecular electrostatic potential and Mulliken atomic charges analysis.

Brittle to Semibrittle Transition in Quartz Sandstone: Energetics

Science.gov (United States)

Kanaya, Taka; Hirth, Greg

2018-01-01

Triaxial compression experiments were conducted on a quartz sandstone at effective pressures up to 175 MPa and temperatures up to 900°C. Our experiments show a transition from brittle faulting to semibrittle faulting with an increase in both pressure and temperature. The yield behavior of samples deformed in the semibrittle regime follows a compactant elliptical cap at low strain, but evolves to a dilatant Mohr-Coulomb relationship with continued compaction. Optical microscopy indicates that semibrittle deformation involves cataclastic flow through shear-enhanced compaction and grain crushing; however, transmission electron microscopy shows evidence for dislocation glide in limited portions of samples. To constrain the relative contribution of brittle and crystal plastic mechanisms, we estimate the partitioning of the inelastic work into the dissipation energy for microcracking, intergranular frictional slip, and dislocation glide. We conclude that semibrittle deformation is accommodated primarily by cataclastic mechanisms, with only a limited contribution from crystal plasticity. Mechanical data, acoustic emission records, and analysis of surface energy all indicate the activation of subcritical cracking at elevated temperature. Hence, we infer that the enhancement of subcritical cracking is responsible for the transition to semibrittle flow through promoting distributed grain-scale fractures and millimeter-scale shear bands. Subcritical cracking promotes the nucleation of microfractures at lower stresses, and the resulting decrease in flow stress retards the propagation of transgranular microfractures. Our study illuminates the important role of temperature on the micromechanics of the transition from brittle faulting to cataclastic flow in the Earth.

Quartz-molybdenite veins in the Priestly Lake granodiorite, north-central Maine

Science.gov (United States)

Ayuso, Robert A.; Shank, Stephen G.

1983-01-01

Quartz-molybdenite veins up to 15 cm in width occur in fine to medium-grained porphyritic biotite-hornblende granodiorite at Priestly Lake north-central Maine. An area of about 150 m x 150 m contains quartz-molybdenite veins; a larger area is characterized by barren quartz veins. Quartz-molybdenite veins are concentrated within the most felsic variants of the intrusion as suggested by lower mafic mineral contents. The pluton has a narrow range in SiO2 (67-70 wt.%), major oxides, and in trace-element compositions. Molybdenite occurs as coarse grained clusters in pockets within the quartz veins, and fills fractures in the quartz veins and host rocks. Disseminated molybdenite in the granodiorite is relatively rare and occurs only in the area characterized by a high density of quartz veins (up to 50 veins per square meter). Alteration envelopes along the quartz veins are very thin or absent, although in some areas the granodiorite appears to be selectively and pervasively altered. Sericite, chlorite, epidote, calcite, pyrite, and quartz are concentrated near the quartz-molybdenite veins. Many of the field and geochemical characteristics of the Priestly Lake pluton are unlike those of major molybdenum-producing areas (Climax, Henderson, Urad). For example, the area of alteration seems to be of limited extent, the host rock is not intensely altered hydrothermally at the surface, the density of fractures is rather low in the mineralized area, and the amount of disseminated molybdenite appears to be small. However, the Priestly Lake pluton may be a small fraction of a concealed batholith as suggested by geophysical data. It is conceivable that the type of mineralization at the surface might be the expression of more extensive molybdenite mineralization at depth. The quartz-molybdenite veins in the Priestly Lake pluton are significant because they indicate that potential molybdenum sources for producing mineralized granites were available at depth. Future studies should be

Electrochemically shape-controlled synthesis in deep eutectic solvents of Pt nanoflowers with enhanced activity for ethanol oxidation

International Nuclear Information System (INIS)

Wei Lu; Fan Youjun; Wang Honghui; Tian Na; Zhou Zhiyou; Sun Shigang

2012-01-01

Highlights: ► The electrochemically shape-controlled synthesis in deep eutectic solvents (DESs) has been applied to produce the uniform Pt nanoflowers with sharp single crystal petals and high density of atomic steps. ► The as-prepared Pt nanoflowers exhibit higher electrocatalytic activity and stability than commercial Pt black catalyst toward ethanol electrooxidation. ► The growth of Pt nanoflowers in DESs by the simple electrochemical route is straightforward and controllable in terms of nanoflowers’ shape and size. - Abstract: The electrochemically shape-controlled synthesis in deep eutectic solvents (DESs) has been applied to produce the electrocatalyst of Pt nanoflowers. The uniform Pt nanoflowers with sharp single crystal petals and high density of atomic steps were characterized by SEM, TEM, XRD, XPS and electrochemical tests. The results illustrated that the as-prepared Pt nanoflowers exhibit higher electrocatalytic activity and stability than commercial Pt black catalyst toward ethanol electrooxidation. The growth of Pt nanoflowers in DESs by the simple electrochemical route is straightforward and controllable in terms of nanoflowers’ shape and size, which can be applied in shape-controlled synthesis of other noble metal nanoparticles with high catalytic activity.

X-ray crystal imagers for inertial confinement fusion experiments (invited)

International Nuclear Information System (INIS)

Aglitskiy, Y.; Lehecka, T.; Obenschain, S.; Pawley, C.; Brown, C.M.; Seely, J.

1999-01-01

We report on our continued development of high resolution monochromatic x-ray imaging system based on spherically curved crystals. This system can be extensively used in the relevant experiments of the inertial confinement fusion (ICF) program. The system is currently used, but not limited to diagnostics of the targets ablatively accelerated by the Nike KrF laser. A spherically curved quartz crystal (2d=6.68703 Angstrom, R=200mm) has been used to produce monochromatic backlit images with the He-like Si resonance line (1865 eV) as the source of radiation. Another quartz crystal (2d=8.5099 Angstrom, R=200mm) with the H-like Mg resonance line (1473 eV) has been used for backlit imaging with higher contrast. The spatial resolution of the x-ray optical system is 1.7 μm in selected places and 2 - 3 μm over a larger area. A second crystal with a separate backlighter was added to the imaging system. This makes it possible to make use of all four strips of the framing camera. Time resolved, 20x magnified, backlit monochromatic images of CH planar targets driven by the Nike facility have been obtained with spatial resolution of 2.5 μm in selected places and 5 μm over the focal spot of the Nike laser. We are exploring the enhancement of this technique to the higher and lower backlighter energies. copyright 1999 American Institute of Physics

A high resolution reflecting crystal spectrometer to measure 3 keV pionic hydrogen and deuterium X-rays

International Nuclear Information System (INIS)

Badertscher, A.; Bogdan, M.; Goudsmit, P.F.A.; Knecht, L.; Leisi, H.J.; Schroeder, H.C.; Sigg, D.; Zhao, Z.G.; Chatellard, D.; Egger, J.P.; Jeannet, E.; Aschenauer, E.C.; Gabathuler, K.; Simons, L.M.; Rusi El Hassani, A.J.

1993-01-01

A reflecting crystal spectrometer consisting of three cylindrically bent quartz (110) crystals is described. It was designed to measure the 3 keV K β X-rays from pionic hydrogen and deuterium. Charge coupled devices (CCDs) were used as X-ray detectors. Projecting the reflexes of all three crystals on one common focus, an instrumental energy resolution below 1 eV was obtained at an energy of 2.9 keV. (orig.)

A natural example of fluid-mediated brittle-ductile cyclicity in quartz veins from Olkiluoto Island, SW Finland

Science.gov (United States)

Marchesini, Barbara; Garofalo, Paolo S.; Viola, Giulio; Mattila, Jussi; Menegon, Luca

2017-04-01

recognize three distinct episodes of ductile deformation alternating with at least three brittle episodes. Preliminary fluid inclusion data show that, during crystallization and brittle-viscous deformation, quartz crystals hosted homogeneous and heterogeneous (boiling) aqueous fluids with a large salinity (11.7-0 wt% NaCleq) and Thtot (410-200 °C) range. Boiling occurred at 200-260 °C. Variations of fluid temperature and density (hence, viscosity) may thus have induced localized cyclic switches between brittle and ductile deformation in quartz, with implications on the bulk regional crustal strength. Preliminary EBSD analysis also supports the hypothesis of cyclic switches between brittle and viscous deformation.

Compact and Robust Refilling and Connectorization of Hollow Core Photonic Crystal Fiber Gas Reference Cells

Science.gov (United States)

Poberezhskiy, Ilya Y.; Meras, Patrick; Chang, Daniel H.; Spiers, Gary D.

2007-01-01

This slide presentation reviews a method for refilling and connectorization of hollow core photonic crystal fiber gas reference cells. Thees hollow-core photonic crystal fiber allow optical propagation in air or vacuum and are for use as gas reference cell is proposed and demonstrated. It relies on torch-sealing a quartz filling tube connected to a mechanical splice between regular and hollow-core fibers.

Bacterial interactions with proteins and cells relevant to the development of life-threatening endocarditis studied by use of a quartz-crystal microbalance.

Science.gov (United States)

Krajewski, Stefanie; Rheinlaender, Johannes; Ries, Philip; Canjuga, Denis; Mack, Carmen; Scheideler, Lutz; Schäffer, Tilman E; Geis-Gerstorfer, Jürgen; Wendel, Hans-Peter; Rupp, Frank

2014-05-01

Implant-related infections are a major challenge in clinical routine because of severe complications, for example infective endocarditis (IE). The purpose of this study was to investigate the real-time interaction of S. gordonii with proteins and cells important in the development of IE, in a flow system, by use of a quartz-crystal microbalance (QCM). Acoustic sensors were biologically modified by preconditioning with sterile saliva, platelet-poor plasma (PPP), or platelet-rich plasma (PRP), followed then by perfusion of a bacterial suspension. After perfusion, additional fluorescence and scanning electron microscopic (SEM) studies were performed. The surface structure of S. gordonii was analyzed by atomic force microscopy (AFM). Compared with S. gordonii adhesion on the abiotic sensor surface following normal mass loading indicated by a frequency decrease, adhesion on saliva, PPP, or PRP-conditioned sensors resulted in an increase in frequency. Furthermore, adhesion induced slightly increased damping signals for saliva and PPP-coated sensors but a decrease upon bacterial adhesion to PRP, indicating the formation of a more rigid biofilm. Microscopic analysis confirmed the formation of dense and vital bacterial layers and the aggregation of platelets and bacteria. In conclusion, our study shows that the complex patterns of QCM output data observed are strongly dependent on the biological substrate and adhesion mechanisms of S. gordonii. Overall, QCM sheds new light on the pathways of such severe infections as IE.

Transient kinetic studies of pH-dependent hydrolyses by exo-type carboxypeptidase P on a 27-MHz quartz crystal microbalance.

Science.gov (United States)

Furusawa, Hiroyuki; Takano, Hiroki; Okahata, Yoshio

2008-02-15

pH-Dependent kinetic parameters (k(on), k(off), and k(cat)) of protein (myoglobin) hydrolyses catalyzed by exo-enzyme (carboxypeptidase P, CPP) were obtained by using a protein-immobilized quartz crystal microbalance (QCM) in acidic aqueous solutions. The formation of the enzyme-substrate (ES) complex (k(on)), the decay of the ES complex (k(off)), and the formation of the product (k(cat)) could be analyzed by transient kinetics as mass changes on the QCM plate. The Kd (k(off)/k(on)) value was different from the Michaelis constant Km calculated from (k(off) + k(cat))/k(on) due to k(cat) > k(off). The rate-determining step was the binding step (k(on), and the catalytic rate k(cat) was faster than other k(on) and k(off) values. In the range of pH 2.5-5.0, values of k(on) gradually increased with decreasing pH showing a maximum at pH 3.7, values of k(off) were independent of pH, and k(cat) increased gradually with decreasing pH. As a result, the apparent rate constant (k(cat)/Km) showed a maximum at pH 3.7 and gradually increased with decreasing pH. The optimum pH at 3.7 of k(on) is explained by the optimum binding ability of CPP to the COOH terminus of the substrate with hydrogen bonds. The increase of k(cat) at the lower pH correlated with the decrease of alpha-helix contents of the myoglobin substrate on the QCM.

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.

Quartz Enhanced Photoacoustic Spectroscopy Based Trace Gas Sensors Using Different Quartz Tuning Forks

Directory of Open Access Journals (Sweden)

Yufei Ma

2015-03-01

Full Text Available 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.

Angular dependences of the luminescence and density of photon states in a chiral liquid crystal

Energy Technology Data Exchange (ETDEWEB)

Umanskii, B A; Blinov, L M; Palto, S P [A.V. Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow, Russian Federaion (Russian Federation)

2013-11-30

Luminescence spectra of a laser dye-doped chiral liquid crystal have been studied in a wide range of angles (up to 60°) to the axis of its helical structure using a semicylindrical quartz prism, which made it possible to observe the shift and evolution of the photonic band gap in response to changes in angle. Using measured spectra and numerical simulation, we calculated the spectral distributions of the density of photon states in such a cholesteric crystal for polarised and unpolarised light, which characterise its structure as that of a chiral one-dimensional photonic crystal. (optics of liquid crystals)

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.

Refractometry characteristics of α-quartz after neutron irradiation

International Nuclear Information System (INIS)

Abdkadyrova, I.Kh.

1997-01-01

Lattice structure distortions in irradiated crystalline quartz were studied by refractometry methods. The refractometry constants of α-quartz for the flux of fast neutrons 10 18 - 10 21 neutron/cm 2 were calculated. The critical kinetics of this constants at the phase transformation is observed.(author). 5 refs., 1 fig

Ultra-nanocrystalline diamond nanowires with enhanced electrochemical properties

International Nuclear Information System (INIS)

Shalini, Jayakumar; Lin, Yi-Chieh; Chang, Ting-Hsun; Sankaran, Kamatchi Jothiramalingam; Chen, Huang-Chin; Lin, I.-Nan; Lee, Chi-Young; Tai, Nyan-Hwa

2013-01-01

The effects of N 2 incorporation in Ar/CH 4 plasma on the electrochemical properties and microstructure of ultra-nanocrystalline diamond (UNCD) films are reported. While the electrical conductivity of the films increased monotonously with increasing N 2 content (up to 25%) in the plasma, the electrochemical behavior was optimized for UNCD films grown in (Ar–10% N 2 )/CH 4 plasma. Transmission electron microscopy showed that the main factor resulting in high conductivity in the films was the formation of needle-like nanodiamond grains and the induction graphite layer encapsulating these grains. The electrochemical process for N 2 -incorporated UNCD films can readily be activated due to the presence of nanographite along the grain boundaries of the films. The formation of needle-like diamond grains was presumably due to the presence of CN species that adhered to the existing nanodiamond clusters, which suppressed radial growth of the nanodiamond crystals, promoting anisotropic growth and the formation of needle-like nanodiamond. The N 2 -incorporated UNCD films outperformed other electrochemical electrode materials, such as boron-doped diamond and glassy carbon, in that the UNCD electrodes could sense dopamine, urea, and ascorbic acid simultaneously in the same mixture with clear resolution

Dependence of red thermoluminescence on Eu-anomaly in natural quartzes

Energy Technology Data Exchange (ETDEWEB)

Hashimoto, T; Yokosaka, K; Notoya, S; Ojima, T; Sakaue, S [Niigata Univ. (Japan). Faculty of Science

1993-04-01

The causes of red colour thermoluminescence (RTL) from natural quartz have been sought in the presence of impurity elements. Some impurities in 31 varieties of natural quartz extracts, determined by a neutron activation analysis, have been examined with respect to a meaningful correlation of the RTL to the total detectable TL strength. Generally, the higher impurity contents were found in quartz of volcanic origin, which always emits purely RTL colour, whereas the lower impurities were usually detected in hydrothermal quartz, which emits purely blue TL (BTL) in all absorbed doses. Among the impurities, the middle REE (rare earth elements), involving Eu and Sm, particularly offered considerable correlation with RTL emission with the exception of pegmatite quartz. It was found from the chondrite-normalized REE patterns that a positive Eu anomaly or flattened Eu distribution gave rise to relatively high RTL proportions, while a negative Eu anomaly always showed extremely weak RTL intensity. Thus, it was concluded that the Eu[sup 3+], formed from the oxidizable surrounding or high oxygen fugacity relative to a Cl chondrite formation, is strongly related to the RTL intensity in natural quartz. (author).

Evidence of a Love wave bandgap in a quartz substrate coated with a phononic thin layer

International Nuclear Information System (INIS)

Liu, Ting-Wei; Wu, Tsung-Tsong; Lin, Yu-Ching; Tsai, Yao-Chuan; Ono, Takahito; Tanaka, Shuji

2014-01-01

This paper presents a numerical and experimental study of Love wave propagation in a micro-fabricated phononic crystal (PC) structure consisting of a 2D, periodically etched silica film deposited on a quartz substrate. The dispersion characteristics of Love waves in such a phononic structure were analyzed with various geometric parameters by using complex band structure calculations. For the experiment, we adopted reactive-ion etching with electron-beam lithography to fabricate a submicrometer phononic structure. The measured results exhibited consistency with the numerical prediction. The results of this study may serve as a basis for developing PC-based Love wave devices

Food irradiation dosimetry using thermoluminescence of quartz sand

International Nuclear Information System (INIS)

Khan, H.M.; Ehlermann, D.A.E.

1993-01-01

Thermoluminescence of quartz sand, which is inert and concomitant to several food materials, has been investigated for applications in food irradiation dosimetry and detection of irradiated foods. The glow curves consist of at least three overlapping peaks from 100 to 420 C. The peak at lower temperature is not stable and decays quickly at room temperature. However, the peaks at higher temperature are stable and more useful for dosimetry work. The intensity of the peak at 360 C, measured using different optical filters, shows a linear response in the range of 0.05 to 23 kGy. Stability of these signals at different annealing temperatures has been investigated. Thermoluminescence from adhering minerals and contaminating dust in different food materials has been found useful for the detection of irradiation treatment. Since quartz is frequently one of these minerals, further computerized deconvolution of individual glow peaks from the complex glow curves of quartz sand was carried out which improves the dosimetric results. Possible applications of thermoluminescence of quartz sand in food irradiation dosimetry and detection of irradiated foods have been discussed. (orig.)

Alpha efficiency determination for OSL of quartz extracted from Chinese loess

International Nuclear Information System (INIS)

Lai Zhongping; Zoeller, Ludwig; Fuchs, Markus; Brueckner, Helmut

2008-01-01

We report here the estimates of alpha efficiency for fine grain quartz extracted from Chinese loess using the SAR protocol. For the seven samples, the α-values range from 0.028 to 0.038 with an average of 0.035±0.001. The annealed quartz (450 deg. C, 45 min) has an α-value of 0.030±0.001 which is similar to the α-value of 0.029±0.001 for the non-annealed quartz extracts, suggesting that the α-value is independent of the quartz's thermal history for this sample. We suggest that an α-value of 0.035±0.003 can be adopted for quartz extracted from Chinese loess when calculating the environmental dose rate

Activation analysis of high pure quartz used as packing materials

International Nuclear Information System (INIS)

Luknitskij, V.A.; Morozov, B.A.

1979-01-01

A γ-spectrometric technique of neutron activation determination of microelements in quartz tubes used as a packing material for irradiation in reactors is reported. The analysis of 29 micro-admixtures in quartz tubes of USSR brands ''spectrtosil'' and ''KV'' was carried out. The γ-spectra of ''KV'' quartz irradiated by thermal and epithermal neutrons are presented. The activation by epithermal neutrons provides an activity gain for the nuclei whose resonance integral is high enough as compared to the activation cross-section with regard to thermal neutrons. The activation by epithermal neutrons permits additional determination of W, Cd, V, Th, Mn and Ni and provides for a substantial decrease in the activity of 24 Na, 42 K, 140 La, 46 Sc, 141 Ce, 51 Cr, and 59 Fe, which hinder the determination of the above-mentioned elements. The microelement composition of Soviet-made quartz varieties is compared to that of foreign-made quartz brands

Green-emissive transparent BaSi 2O 5:Eu 2 + film phosphor on quartz glass created by a sputtering thermal diffusion process

Science.gov (United States)

Seo, K. I.; Park, J. H.; Kim, J. S.; Na, Y. H.; Choi, J. C.; Bae, J. S.

2009-10-01

Eu 2+-doped BaSi 2O 5 film phosphors on quartz substrates are fabricated by radio-frequency magnetron sputtering thermal diffusion. The BaSi 2O 5: Eu 2+ phosphor crystals have some preferred orientations that are lattice-spacing matched with the crystallized β- SiO 2 crystals, and they show pore and grain boundary-free morphology with a rod-like shape fused into the crystallized β- SiO 2 crystals. The BaSi 2O 5: Eu 2+ film phosphor has a high transparency, with a transmittance of about 30% in visible light. The BaSi 2O 5: Eu 2+ film phosphor shows 510 nm green emission from the f-d transition of the Eu 2+ ions, and in particular the best sample shows a green photoluminescence brightness of about 5% of a BaSi 2O 5: Eu 2+ powder phosphor screen. These excellences in optical properties can be explained by less optical scattering at pores or grain boundaries, and less reflection at the continuously index-changed interface.

On-line mass spectrometry system for measurements at single-crystal electrodes in hanging meniscus configuration

NARCIS (Netherlands)

Wonders, A.H.; Housmans, T.H.M.; Rosca, V.; Koper, M.T.M.

2006-01-01

We present the construction and some first applications of an On-line electrochemical mass spectrometry system for detecting volatile products formed during electrochemical reactions at a single-crystal electrode in hanging meniscus configuration. The system is based on a small inlet tip made of

Ultra-thin distributed Bragg reflectors via stacked single-crystal silicon nanomembranes

Energy Technology Data Exchange (ETDEWEB)

Cho, Minkyu; Seo, Jung-Hun; Lee, Jaeseong; Mi, Hongyi; Kim, Munho; Ma, Zhenqiang, E-mail: mazq@engr.wisc.edu [Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Zhao, Deyin; Zhou, Weidong [Nanophotonics Lab, Department of Electrical Engineering, University of Texas at Arlington, Arlington, Texas 76019 (United States); Yin, Xin; Wang, Xudong [Department of Material Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

2015-05-04

In this paper, we report ultra-thin distributed Bragg reflectors (DBRs) via stacked single-crystal silicon (Si) nanomembranes (NMs). Mesh hole-free single-crystal Si NMs were released from a Si-on-insulator substrate and transferred to quartz and Si substrates. Thermal oxidation was applied to the transferred Si NM to form high-quality SiO{sub 2} and thus a Si/SiO{sub 2} pair with uniform and precisely controlled thicknesses. The Si/SiO{sub 2} layers, as smooth as epitaxial grown layers, minimize scattering loss at the interface and in between the layers. As a result, a reflection of 99.8% at the wavelength range from 1350 nm to 1650 nm can be measured from a 2.5-pair DBR on a quartz substrate and 3-pair DBR on a Si substrate with thickness of 0.87 μm and 1.14 μm, respectively. The high reflection, ultra-thin DBRs developed here, which can be applied to almost any devices and materials, holds potential for application in high performance optoelectronic devices and photonics applications.

Novel polymeric potassium complex: Its synthesis, structural characterization, photoluminescence and electrochemical properties

Energy Technology Data Exchange (ETDEWEB)

Ceyhan, Goekhan [Chemistry Department, K.Maras Suetcue Imam University, 46100 K.Maras (Turkey); Tuemer, Mehmet, E-mail: mtumer@ksu.edu.tr [Chemistry Department, K.Maras Suetcue Imam University, 46100 K.Maras (Turkey); Koese, Muhammet; McKee, Vickie [Chemistry Department, Loughborough University, LE11 3TU Leicestershire (United Kingdom)

2012-03-15

In this paper, we obtained a novel poly(vanillinato potassium) complex (PVP) as a single crystal and characterized by analytical and spectroscopic methods. A single crystal of the PVP was obtained from the acetone solution. X-ray structural data show that crystals contain polymeric K{sup +} complex of vanillin. Each potassium ion in the polymeric structure is identical and seven-coordinate, bonded to two methoxy, two phenoxy and three aldehyde oxygen atoms from four vaniline molecules. Two aldehyde oxygen atoms are bridging between potassium ions. It crystallizes in the monoclinic system, space group P2{sub 1}/c, with lattice parameters a=9.6215(10) A, b=17.4139(19) A, c=9.6119(10) A, {beta}=100.457(2) Degree-Sign and Z=4. Thermal properties of the PVP were investigated by TGA, DTA and DSC methods. The electrochemical properties of the complex were studied in different solvents and at various scan rates. The luminescence properties of the complex in different solvents and at different pH values have been investigated. The results show that the complex exhibits more efficient luminescence property in CH{sub 3}CN and n-butanol. - Highlights: Black-Right-Pointing-Pointer Novel polymeric potassium complex was prepared and fully characterized. Black-Right-Pointing-Pointer X-ray crystal structure of complex was reported. Black-Right-Pointing-Pointer Electrochemical properties of compound were investigated. Black-Right-Pointing-Pointer Thermal and DSC measurements of complex were examined.

Crystal structure studies on plate/shelf like disodium ditungstate

Indian Academy of Sciences (India)

Inorganic materials; disodium ditungstate; crystal structure; scanning electron microscopy; X-ray ... generation, and horizontal electric furnace with quartz tube ... Unit cell dimensions: a = 7·22192(11) Е, b = 11·91559(17) Е, c = 14·74755(23) Е. Cell content: 8 Na2W2O7). Atom. Position. X(σ(X)). Y(σ(Y)). Z(σ(Z)). B(σ(B)). W (1).

Soil chemistry in lithologically diverse datasets: the quartz dilution effect

Science.gov (United States)

Bern, Carleton R.

2009-01-01

National- and continental-scale soil geochemical datasets are likely to move our understanding of broad soil geochemistry patterns forward significantly. Patterns of chemistry and mineralogy delineated from these datasets are strongly influenced by the composition of the soil parent material, which itself is largely a function of lithology and particle size sorting. Such controls present a challenge by obscuring subtler patterns arising from subsequent pedogenic processes. Here the effect of quartz concentration is examined in moist-climate soils from a pilot dataset of the North American Soil Geochemical Landscapes Project. Due to variable and high quartz contents (6.2–81.7 wt.%), and its residual and inert nature in soil, quartz is demonstrated to influence broad patterns in soil chemistry. A dilution effect is observed whereby concentrations of various elements are significantly and strongly negatively correlated with quartz. Quartz content drives artificial positive correlations between concentrations of some elements and obscures negative correlations between others. Unadjusted soil data show the highly mobile base cations Ca, Mg, and Na to be often strongly positively correlated with intermediately mobile Al or Fe, and generally uncorrelated with the relatively immobile high-field-strength elements (HFS) Ti and Nb. Both patterns are contrary to broad expectations for soils being weathered and leached. After transforming bulk soil chemistry to a quartz-free basis, the base cations are generally uncorrelated with Al and Fe, and negative correlations generally emerge with the HFS elements. Quartz-free element data may be a useful tool for elucidating patterns of weathering or parent-material chemistry in large soil datasets.

Importance of surface characteristics of QUARTZ DQ 12 for acute inflammation

Energy Technology Data Exchange (ETDEWEB)

Albrecht, C.; Becher, A.; Scins, R.P.F.; Hoehr, D.; Unfried, K.; Knaapen, A.M.; Borm, P.J.A. [Institut fuer medizinische Forschung (IUF), Duesseldorf (Germany)

2004-07-01

Although quartz is known to induce inflammation in rat lungs, mechanisms are not yet fully understood. The importance of particle surface characteristics was investigated in vivo after intratracheal instillation of different preparations of quartz in rat lungs. Three days after instillation of 2 mg DQ12 quartz, or DQ12 coated with polyvinylpyridine-N-oxide (PVNO) or Aluminium lactate (AL), lungs of female Wistar rats were lavaged in situ to determine markers of inflammation. Control rats received saline or the coating substances alone. DQ12 induced a marked inflammatory response, as indicated by a significant increase in the number of neutrophils and macrophages, as well as in the levels of b-glucuronidase and myeloperoxidase. None of these inflammatory markers was increased for both coated quartz preparations, with the exception of neutrophil influx which was also increased after treatment with AL quartz. Our results indicate that surface characteristics are important in the onset of quartz-induced lung inflammation which could imply a different development of persistent inflammation. This will be investigated in later follow-up time points of the same animal study. (orig.)

Quartz-Enhanced Photoacoustic Spectroscopy Sensor with a Small-Gap Quartz Tuning Fork

Directory of Open Access Journals (Sweden)

Yu-Fei Ma

2018-06-01

Full Text Available A highly sensitive quartz-enhanced photoacoustic spectroscopy (QEPAS sensor based on a custom quartz tuning fork (QTF with a small-gap of 200 μm was demonstrated. With the help of the finite element modeling (FEM simulation software COMSOL, the change tendency of the QEPAS signal under the influence of the laser beam vertical position and the length of the micro-resonator (mR were calculated theoretically. Water vapor (H2O was selected as the target analyte. The experimental results agreed well with those of the simulation, which verified the correctness of the theoretical model. An 11-fold signal enhancement was achieved with the addition of an mR with an optimal length of 5 mm in comparison to the bare QTF. Finally, the H2O-QEPAS sensor, which was based on a small-gap QTF, achieved a minimum detection limit (MDL of 1.3 ppm, indicating an improvement of the sensor performance when compared to the standard QTF that has a gap of 300 μm.

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

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.

Isolation, crystallization and crystal structure determination of bovine kidney Na(+),K(+)-ATPase.

Science.gov (United States)

Gregersen, Jonas Lindholt; Mattle, Daniel; Fedosova, Natalya U; Nissen, Poul; Reinhard, Linda

2016-04-01

Na(+),K(+)-ATPase is responsible for the transport of Na(+) and K(+) across the plasma membrane in animal cells, thereby sustaining vital electrochemical gradients that energize channels and secondary transporters. The crystal structure of Na(+),K(+)-ATPase has previously been elucidated using the enzyme from native sources such as porcine kidney and shark rectal gland. Here, the isolation, crystallization and first structure determination of bovine kidney Na(+),K(+)-ATPase in a high-affinity E2-BeF3(-)-ouabain complex with bound magnesium are described. Crystals belonging to the orthorhombic space group C2221 with one molecule in the asymmetric unit exhibited anisotropic diffraction to a resolution of 3.7 Å with full completeness to a resolution of 4.2 Å. The structure was determined by molecular replacement, revealing unbiased electron-density features for bound BeF3(-), ouabain and Mg(2+) ions.

Discussion meet on electroanalytical techniques and their applications

International Nuclear Information System (INIS)

Aggarwal, S.K.; Gopinath, N.; Govindan, R.

2008-02-01

Electrochemistry is truly an interdisciplinary science and plays an important role in different branches of science and technology. The present Discussion Meet on ElectroAnalytical Techniques (DM- ELANTE-2008) is focused on the update of various electroanalytical techniques which have brought out a substantial change in electroanalytical chemistry. The aim of this Discussion Meet is to provide a forum to all the electroanalytical scientists to discuss their recent findings and information, learn from the mutual experiences and interests, and to promote cooperation both nationally and internationally. It is proposed to have tutorial lectures as well as invited talks during the Discussion Meet on various electroanalytical techniques including Electrochemical Impedance Spectroscopy (EIS), Spectro-electrochemistry, Scanning Electrochemical Microscopy (SECM), Electrochemical Quartz Crystal Microbalance (EQCM), Surface Plasmon Resonance (SPR) etc. Papers relevant to INIS are indexed separately

Toroidal helical quartz forming machine

International Nuclear Information System (INIS)

Hanks, K.W.; Cole, T.R.

1977-01-01

The Scyllac fusion experimental machine used 10 cm diameter smooth bore discharge tubes formed into a simple toroidal shape prior to 1974. At about that time, it was discovered that a discharge tube was required to follow the convoluted shape of the load coil. A machine was designed and built to form a fused quartz tube with a toroidal shape. The machine will accommodate quartz tubes from 5 cm to 20 cm diameter forming it into a 4 m toroidal radius with a 1 to 5 cm helical displacement. The machine will also generate a helical shape on a linear tube. Two sets of tubes with different helical radii and wavelengths have been successfully fabricated. The problems encountered with the design and fabrication of this machine are discussed

Dynamics of the α-β phase transitions in quartz and cristobalite as observed by in-situ high temperature 29Si and 17O NMR

Science.gov (United States)

Spearing, Dane R.; Farnan, Ian; Stebbins, Jonathan F.

1992-12-01

Relaxation times (T1) and lineshapes were examined as a function of temperature through the α-β transition for 29Si in a single crystal of amethyst, and for 29Si and 17O in cristobalite powders. For single crystal quartz, the three 29Si peaks observed at room temperature, representing each of the three differently oriented SiO4 tetrahedra in the unit cell, coalesce with increasing temperature such that at the α-β transition only one peak is observed. 29Si T1's decrease with increasing temperature up to the transition, above which they remain constant. Although these results are not uniquely interpretable, hopping between the Dauphiné twin related configurations, α1 and α2, may be the fluctuations responsible for both effects. This exchange becomes observable up to 150° C below the transition, and persists above the transition, resulting in β-quartz being a time and space average of α1 and α2. 29Si T1's for isotopically enriched powdered cristobalite show much the same behavior as observed for quartz. In addition, 17O T1's decrease slowly up to the α-β transition at which point there is an abrupt 1.5 order of magnitude drop. Fitting of static powder 17O spectra for cristobalite gives an asymmetry parameter (η) of 0.125 at room T, which decreases to <0.040 at the transition temperature. The electric field gradient (EFG) and chemical shift anisotropy (CSA), however, remain the same, suggesting that the decrease in η is caused by a dynamical rotation of the tetrahedra below the transition. Thus, the mechanisms of the α-β phase transitions in quartz and cristobalite are similar: there appears to be some fluctuation of the tetrahedra between twin-related orientations below the transition temperature, and the β-phase is characterized by a dynamical average of the twin domains on a unit cell scale.

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.

Nanogravimetric studies of tungsten oxide thin films obtained by the polymeric precursor method

International Nuclear Information System (INIS)

Fernandes, V.C.; Santos, M.C.; Bulhoes, L.O.S.

2007-01-01

In this work, the intercalation/de-intercalation process of Li + ions in the tungsten oxide matrix was investigated. The reaction mechanism involved was also investigated. The WO 3 films, prepared by the polymeric precursor method, were deposited on a Pt covered quartz crystal using the dip-coating technique. The electrolyte was 0.1 mol L -1 LiClO 4 in acetonitrile. The morphology and structure of the deposit was accomplished by scanning electron microscopy and X-ray diffraction, respectively. In the electrochemical quartz crystal nanobalance results, it was observed that the mass transport as well as the kinetic processes involved are facilitated in the films cycled at lower potential sweep-rates. The mass variation data as a function of the charge variations in the anodic and cathodic regions indicate the participation of solvent molecules (acetonitrile) during the Li + ion intercalation/de-intercalation process. This was confirmed by the development of a model of the species flux as a function of the potential

Application of hydrometallurgy techniques in quartz processing and purification: a review

Science.gov (United States)

Lin, Min; Lei, Shaomin; Pei, Zhenyu; Liu, Yuanyuan; Xia, Zhangjie; Xie, Feixiang

2018-04-01

Although there have been numerous studies on separation and purification of metallic minerals by hydrometallurgy techniques, applications of the chemical techniques in separation and purification of non-metallic minerals are rarely reported. This paper reviews disparate areas of study into processing and purification of quartz (typical non-metallic ore) in an attempt to summarize current work, as well as to suggest potential for future consolidation in the field. The review encompasses chemical techniques of the quartz processing including situations, progresses, leaching mechanism, scopes of application, advantages and drawbacks of micro-bioleaching, high temperature leaching, high temperature pressure leaching and catalyzed high temperature pressure leaching. Traditional leaching techniques including micro-bioleaching and high temperature leaching are unequal to demand of modern glass industry for quality of quartz concentrate because the quartz products has to be further processed. High temperature pressure leaching and catalyzed high temperature pressure leaching provide new ways to produce high-grade quartz sand with only one process and lower acid consumption. Furthermore, the catalyzed high temperature pressure leaching realizes effective purification of quartz with extremely low acid consumption (no using HF or any fluoride). It is proposed that, by integrating the different chemical processes of quartz processing and expounding leaching mechanisms and scopes of application, the research field as a monopolized industry would benefit.

Surface Initiated Polymerizations via e-ATRP in Pure Water

Directory of Open Access Journals (Sweden)

Seyed Schwan Hosseiny

2013-10-01

Full Text Available Here we describe the combined process of surface modification with electrochemical atom transfer radical polymerization (e-ATRP initiated from the surface of a modified gold-electrode in a pure aqueous solution without any additional supporting electrolyte. This approach allows for a very controlled growth of the polymer chains leading towards a steady increase in film thickness. Electrochemical quartz crystal microbalance displayed a highly regular increase in surface confined mass only after the addition of the pre-copper catalyst which is reduced in situ and transformed into the catalyst. Even after isolation and washing of the modified electrode surface, reinitiation was achieved with retention of the controlled electrochemical ATRP reaction. This reinitiation after isolation proves the livingness of the polymerization. This approach has interesting potential for smart thin film materials and offers also the possibility of post-modification via additional electrochemical induced reactions.

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

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C. O. Okpanachi

2017-03-01

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.

Pulsed ESR measurements of oxygen deficient type centers in various quartz

International Nuclear Information System (INIS)

Yamanaka, C.; Kohno, H.; Ikeya, M.

1996-01-01

Phase-memory times T M for E'-centers in various quartz samples were measured by pulse-ESR. Manually ground quartz followed by γ-irradiation, α-irradiated quartz and that from a natural uranium deposit showed T M M of 15-18μs. Natural SiO 2 with dense spins, (∼ 3.96 Ga) and sandstone from an impact crater were also examined. (author)

Single-crystal filters for attenuating epithermal neutrons and gamma rays in reactor beams

DEFF Research Database (Denmark)

Rustad, B.M.; Als-Nielsen, Jens Aage; Bahnsen, A.

1965-01-01

Cross section of representative samples of bismuth and quartz were measured at room and liquid nitrogen temperatures over neutron energy range of 0.0007 to 2.0 ev to obtain data for design of single-crystal 32-cm bismuth filters for attenuating fast neutrons and γ-rays in reactor beams; filters may...

Crystallization and preliminary X-ray diffraction analysis of West Nile virus

International Nuclear Information System (INIS)

Kaufmann, Bärbel; Plevka, Pavel; Kuhn, Richard J.; Rossmann, Michael G.

2010-01-01

Crystals of infectious West Nile virus were obtained and diffracted at best to about 25 Å resolution. Preliminary analysis of the diffraction pattern suggested tight hexagonal packing of the intact virus. West Nile virus, a human pathogen, is closely related to other medically important flaviviruses of global impact such as dengue virus. The infectious virus was purified from cell culture using polyethylene glycol (PEG) precipitation and density-gradient centrifugation. Thin amorphously shaped crystals of the lipid-enveloped virus were grown in quartz capillaries equilibrated by vapor diffusion. Crystal diffraction extended at best to a resolution of about 25 Å using synchrotron radiation. A preliminary analysis of the diffraction images indicated that the crystals had unit-cell parameters a ≃ b ≃ 480 Å, γ = 120°, suggesting a tight hexagonal packing of one virus particle per unit cell

Effects of crystal defects on the diffuse scattering of X-rays

International Nuclear Information System (INIS)

Kremser, R.

1974-01-01

This thesis concerns with the influence of crystal defects in germanium-drifted silicium and in α=quartz on the intensity of the diffuse X-ray scattering. The experiments were performed at low and high temperatures to show the effect of the atomic thermal motion on the intensity of the diffuse maxima. The comparison of the results for pure silicium and for the germanium-drifted crystal gives information about the relation between the frequency-spectra and the defects of the drifted silicium. For α-quarts it was not possible to relate unequivocally the observed changes in the intensity to individual defects. (C.R.)

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

archaeological samples show very different OSL sensitivities. In this paper we report on studies of the effect of high temperature annealing on the OSL and phototransferred TL (PTTL) signals from sedimentary and synthetic quartz. A dramatic enhancement of both OSL and PTTL sensitivity was found especially...... in the temperature range 500-800 degrees C. Computer simulations of the possible effects are shown to produce data that agree in all essential details with the experimental observations. It is further demonstrated that the enhanced OSL sensitivity as a function of annealing temperature is not a pre-dose effect....... 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...

An experimental study of hydroxyl in quartz using infrared spectroscopy and ion microprobe techniques

Energy Technology Data Exchange (ETDEWEB)

Rovetta, M. R.; Blacic, J. D.; Hervig, R. L.; Holloway, J. R.

1989-05-10

We have measured the concentrations of hydroxyl, deuterium, Al, Fe, Li,Na, K, and Rb in a natural quartz crystal before and after hydrothermaltreatment at 1.5 GPa and 800/degree/--1050 /degree/C. We employed microbeam infraredspectroscopy and ion probe techniques to avoid impurities trapped in healedcracks and fluid inclusions that might bias a normal bulk analysis.The /ital f//sub H/sub 2// of our experiments were buffered to thehematite-magnetite-(OH)fluid, nickel-nickel oxide-(OH)fluid, oriron-wustite-(OH)fluid phase assemblages. After hydrothermal treatment,the samples contained local concentrations of hydrogen or deuterium ofseveral hundred atoms/10/sup 6/ Si (the starting crystal contained 45 H/10/sup 6/ Si).We did several experiments with Al/sub 2/O/sub 3/ or RbCl added to the sample chargeand found local Al enrichment where the deuterium concentration was highbut no Rb enrichment. Finally, we measured trace elements and hydroxyl in aquartz sample after plastic deformation in a talc furnace assembly; inregions of the sample containing basal and prismatic deformation lamellae(but no visible healed microcracks at 400/times/ optical magnification)hydroxyl had increased to /similar to/200 oO/10/sup 6/ Si with no increase in Al or Fe.Samples enriched in hydroxyl but not Al (including the plastically strainedsample) gave infrared spectra resembling natural amethyst crystals.

Quartz dissolution and silica deposition in hot-dry-rock geothermal systems

Energy Technology Data Exchange (ETDEWEB)

Robinson, B.A.

1982-07-01

The kinetics of quartz dissolution control the produced fluid dissolved silica concentration in geothermal systems in which the downhole residence time is finite. The produced fluid of the Phase I, Run Segment 5 experimental Hot Dry Rock (HDR) geothermal system at Fenton Hill, NM, was undersaturated with respect to quartz in one pass through the reservoir, suggesting that the rate of granite dissolution governed the outlet dissolved silica concentration in this system. The literature data for the rate of quartz dissolution in water from 65 to 625/sup 0/C is correlated using an empirical rate law which is first order in quartz surface area and degree of undersaturation of the fluid. The Arrhenius plot (ln k vs T/sup -1/) is linear over eight orders of magnitude of the rate constant, verifying the validity of the proposed rate expression. Carefully performed quartz dissolution experiments in the present study duplicated the literature data and completed the data base in the temperature range from 150 to 250/sup 0/C. Identical experiments using crushed granite indicate that the rate of quartz dissolution in the presence of granite could be as much as 1 to 2 orders of magnitude faster than the rates observed in the pure quartz experiments. A temperature dependent HDR reservoir model incorporates the quartz dissolution rate law to simulate the dissolved silica behavior during the Fenton Hill Run Segment 5 experiment. For this low-permeability, fracture-dominated reservoir, the assumptions of one-dimensional plug flow through a vertically-inclined rectangular fracture and one-dimensional rock heat conduction perpendicular to the direction of flow are employed. These simplifications lead to an analytical solution for the temperature field in the reservoir.

Ionic diffusion in quartz studied by transport measurements, SIMS and atomistic simulations

International Nuclear Information System (INIS)

Sartbaeva, Asel; Wells, Stephen A; Redfern, Simon A T; Hinton, Richard W; Reed, Stephen J B

2005-01-01

Ionic diffusion in the quartz-β-eucryptite system is studied by DC transport measurements, SIMS and atomistic simulations. Transport data show a large transient increase in ionic current at the α-β phase transition of quartz (the Hedvall effect). The SIMS data indicate two diffusion processes, one involving rapid Li + motion and the other involving penetration of Al and Li atoms into quartz at the phase transition. Atomistic simulations explain why the fine microstructure of twin domain walls in quartz near the transition does not hinder Li + diffusion

SPHERICAL MICROPARTICLES FROM GOLD–BEARING QUARTZ VEINS OF THE IROKINDA DEPOSIT, WESTERN TRANSBAIKALIA

Directory of Open Access Journals (Sweden)

A. V. Tatarinov

2016-01-01

.The consequence of metamorphism, i.e. deformational or mechano-chemical transformations of rocks in Irokinda, as well as the autochthon (the rock bed of the Kelyano-Irokinda belt, is the gas-water (‘hydrothermal’ system capable of forming the spherical ore particles with low-temperature mineral rims.The main feature of the structure of the spherical microparticles in Irokinda is a sharp contrast of the crystallization conditions of the metal nodes and their rims. Similar conditions leading to formation of contrasting mineral associations, that are similar in compositions to the discussed spherules, are characteristic of the gas-water-lithoclastitic and gas-water stages of mud volcanoes. For these stages, we suggest the cavitation mechanism of formation of spherical metal particles of Fe, Fe–Cr and other compositions, which is accompanied by combustion (pyrogenic melt and pyrolysis of hydrocarbon components of the fluid. This mechanism, with the exception of the origin of the melt (in this case, of the friction type seems to most closely correspond to the actual data.  The spheroids are likely to have formed in the pre-ore stage of formation of the quartz veins.The high-temperature metal spherical microparticles revealed in our study can be regarded as specific indicators showing conditions in which the ore-forming system of the dynamo-metamorphic type was functioning to produce gold mineralization on the Irokinda deposit. The structure and composition of these microparticles differ from those of the microspherules from other gold deposits in Transbaikalia (black shale formation in Sukhoi Log, and low–sulphide gold–quartz ore formation in Pervenets, which also belong to the dynamogenic genetic type. However, the ore-forming systems of the compared deposits have two common factors that contribute to formation of spherical microparticles – high tectonic activity manifested by repeated (impulse-type tectonic movements, and the associated unstable pressure conditions. The

Organic compounds in fluid inclusions of Archean quartz-Analogues of prebiotic chemistry on early Earth.

Science.gov (United States)

Schreiber, Ulrich; Mayer, Christian; Schmitz, Oliver J; Rosendahl, Pia; Bronja, Amela; Greule, Markus; Keppler, Frank; Mulder, Ines; Sattler, Tobias; Schöler, Heinz F

2017-01-01

The origin of life is still an unsolved mystery in science. Hypothetically, prebiotic chemistry and the formation of protocells may have evolved in the hydrothermal environment of tectonic fault zones in the upper continental crust, an environment where sensitive molecules are protected against degradation induced e.g. by UV radiation. The composition of fluid inclusions in minerals such as quartz crystals which have grown in this environment during the Archean period might provide important information about the first organic molecules formed by hydrothermal synthesis. Here we present evidence for organic compounds which were preserved in fluid inclusions of Archean quartz minerals from Western Australia. We found a variety of organic compounds such as alkanes, halocarbons, alcohols and aldehydes which unambiguously show that simple and even more complex prebiotic organic molecules have been formed by hydrothermal processes. Stable-isotope analysis confirms that the methane found in the inclusions has most likely been formed from abiotic sources by hydrothermal chemistry. Obviously, the liquid phase in the continental Archean crust provided an interesting choice of functional organic molecules. We conclude that organic substances such as these could have made an important contribution to prebiotic chemistry which might eventually have led to the formation of living cells.

Three-dimensional thermoluminescence spectra of different origin quartz from Altay Orogenic belt, Xinjiang, China

International Nuclear Information System (INIS)

Tan Kaixuan; Liu Zehua; Zeng Sheng; Liu Yan; Xie Yanshi; Rieser, Uwe

2009-01-01

Three-dimensional thermoluminescence spectra are measured for different types of geological origin quartz from the Altay orogenic belt, northern Xinjiang, China. The results show striking differences which appear to be characteristic of their geological origin. Granitic quartz is dominated by emission bands at 420-430 nm, 550-560 nm, at a temperature of 170 deg. C. Pegmatite quartz is characterized by an intense 480 nm emission band at 170 deg. C. Volcanic quartz has exclusive UV (340-360 nm) and violet (410-430 nm) emission bands. Hydrothermal quartz exhibits very different TL spectral characteristics because of different hydrothermal activity and mineralization. Only one TL peaks at 485 nm/170 deg. C was observed in sedimentary quartz. An intense 730 nm emission band observed at 170 deg. C considered generally to be characteristics of feldspar was observed in quartz from granite and hydrothermal Au-bearing quartz. This TL peak is probably related to the centre of [FeO 4 ] 0 on an Si site. All samples show an intense 990-1000 nm emission band at 330 deg. C. Identical types of quartz formed in different regions or different geological and tectonic settings can also exhibit striking differences in TL spectra.

Microgravimetric Studies of Selenium Electrodeposition Onto Different Substrates

Directory of Open Access Journals (Sweden)

Kowalik R.

2014-10-01

Full Text Available The mechanism of selenium electrodeposition from sulfuric acid solution on different substrates was studied with the electrochemical techniques. The cyclic voltammetry was combined with the quartz crystal microbalance technique to analyze selenium deposition process. The electrochemical reduction of selenous acid on gold, silver and copper electrodes was investigated. It was found that reduction of selenous acid is a very complex process and it strongly depends from the applied substrate. The voltammetric measurements indicate the range of potentials in which the process of reduction of selenous acids on the applied substrate is possible. Additionally, the microgravimetric data confirm the deposition of selenium and they reveal the mechanism of the deposition process.

Characterization of ferritin core on redox reactions as a nanocomposite for electron transfer

International Nuclear Information System (INIS)

Shin, Kwang Min; Watt, Richard K.; Watt, Gerald D.; Choi, Sang H.; Kim, Hyug-Han; Kim, Sun I.; Kim, Seon Jeong

2010-01-01

The kinetics of the change in mass related to the release from and deposition onto the cavities of a ferritin in the SWCNT nanocomposite by electrochemical redox reactions, and the effects of the SWCNT on the kinetics of the variation in mass of the ferritin nanocomposite were characterized using an electrochemical quartz crystal microbalance. The change in mass of reconstituted ferritin in the SWCNT nanocomposite shows reversible variation and stability of the ferritin/SWCNT nanocomposite on redox reactions was confirmed by using a coreless apoferritin and a Fe 2+ chelating agent. The ferritin/SWCNT nanocomposite is a good candidate for applications based on electron transfer, such as biosensor, biobatteries and electrodes for biofuel cell.

Charge transportation in polyaniline/V2O5 composites

International Nuclear Information System (INIS)

Huguenin, Fritz; Torresi, Roberto M.

2004-01-01

In this work, composites formed from a mixture of V 2 O 5 and polyaniline (PANI) were investigated, for applications as cathode materials for secondary lithium batteries. Electrochemical quartz crystal microbalance (EQCM) data show that charge compensation in the [PANI] 0.3 V 2 O 5 nanocomposite is achieved predominantly by Li + migration. However, the charge compensation in the [PANI]V 2 O 5 microcomposite occurs by Li + and Cl O 4 - transport. Electrochemical Impedance Spectroscopy (EIS) measurements reveal several benefits of nanohybrid formation, including the achievement of shorter ionic diffusion pathways, the higher diffusion rate of the lithium ion and also the higher electronic conductivity, which are responsible for a synergetic effect of the energy storage properties. (author)

Ionic transport in polypyrrole doped with dianionic counterion hexafluorosilicate

International Nuclear Information System (INIS)

Kepas, Anna; Grzeszczuk, Maria

2006-01-01

Electrodeposition, redox switching, ion transport/exchange, surface topography for a thin polypyrrole film on gold in aqueous sodium hexafluorosilicate solution is reported. The properties have been compared with that corresponding to polypyrrole doped with hexafluoroaluminate and related systems. The dianionic counterion enhances electroactivity of the polymer, slows down ionic transport in the polymer phase, makes a strong impact on a surface structure of the polymer film. An improvement in stability of the anion-exchanger properties is observed. Several electroanalytical methods: chronoamperometry (Canada), cyclic voltammetry (CV), electrochemical quartz crystal microbalance (EQCM), electrochemical impedance spectroscopy (EIS), and a microscopic examination of the polymer film surface by scanning electron microscopy (SEM) have been used in the experimental work

Synthesis, crystal structure, fluorescence and electrochemical studies of a new tridentate Schiff base ligand and its nickel(II) and palladium(II) complexes

Science.gov (United States)

Shafaatian, Bita; Soleymanpour, Ahmad; Kholghi Oskouei, Nasim; Notash, Behrouz; Rezvani, Seyyed Ahmad

2014-07-01

A new unsymmetrical tridentate Schiff base ligand was derived from the 1:1 M condensation of ortho-vanillin with 2-mercaptoethylamine. Nickel and palladium complexes were obtained by the reaction of the tridentate Schiff base ligand with nickel(II) acetate tetrahydrate and palladium(II) acetate in 2:1 M ratio. In nickel and palladium complexes the ligand was coordinated to metals via the imine N and enolic O atoms. The S groups of Schiff bases were not coordinated to the metals and S-S coupling was occured. The complexes have been found to possess 1:2 Metal:Ligand stoichiometry and the molar conductance data revealed that the metal complexes were non-electrolytes. The complexes exhibited octahedral coordination geometry. The emission spectra of the ligand and its complexes were studied in methanol. Electrochemical properties of the ligand and its metal complexes were investigated in the CH3CN solvent at the 100 mV s-1 scan rate. The ligand and metal complexes showed both reversible and quasi-reversible processes at this scan rate. The Schiff base and its complexes have been characterized by IR, 1H NMR, UV/Vis, elemental analyses and conductometry. The crystal structure of nickel complex has been determined by single crystal X-ray diffraction.

Content of some microelements in Bulgarian quartz

International Nuclear Information System (INIS)

Kostadinov, K.; Kuleff, I.; Djingova, R.; Todorovski, D.

1982-01-01

Data on the content of As, Au, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Eu, Fe, Hf, Hg, Ir, K, La, Lu, Mn, Nd, Na, Rb, Sb, Sm, Ta, Tb, Sc, Th, U, W, Yb, Zn obtained by instrumental neutron activation analysis are reported. The method is published elsewhere (Kuleff, I. et J. Radional. Chem. 62 (1981) 187). The results of other authors for the amount of Al, Li, Ti, obtained by atomic absorption spectrometry and Cu, P measured by destructive neutron activation analysis are also reported for 3 batches of electrothermal quartz glass, manufactured by ''Svetlina'' plant in Sliven, Bulgaria. The results for Bulgarian quartz glass are compared with literature and authors' data for similar quality glasses produced in England, France, FRG, GDR, USA and USSR. The results show that the amount of As, Au, Cd, Ce, Co, Cs, Eu, Hg, La, Ta, Yb in Bulgarian made quartz glass is lower than in a number of other similar glasses and the amount of the other impurities is close to the mean values. (authors)

A new hybrid photomultiplier tube as detector for scintillating crystals

International Nuclear Information System (INIS)

De Notaristefani, F.; Vittori, F.; Puertolas, D.

2002-01-01

In this work, we have attentively studied the performance of a new hybrid photomultiplier tube (HPMT) as detector for photons from scintillating crystals. The HPMT is equipped with a YAP window in order to improve light collection and increase measured light response from scintillating crystals. Several measurements have been performed on BGO, LSO, CsI(Tl) and NaI(Tl) planar crystals having three different surface treatments as well as on YAP : Ce and CsI(Tl) matrices. Such crystals have been coupled to two HPMTs, one equipped with a YAP window (Y-HPMT) and the other with a conventional quartz window (Q-HPMT). Measurements on crystals coupled to the Y-HPMT have shown a consistent improvement of the light response, thanks to the presence of the YAP window. Indeed, the light response measured with the Y-HPMT was on average equal to 1.5, 2.1 and 2.6 times that obtained with the Q-HPMT for planar crystals with white painted (diffusive), fine ground and polished rear surfaces, respectively. With regards to crystal matrices, we measured a light response increase of about 1.2 times

Particle Characterization for a Protein Drug Product Stored in Pre-Filled Syringes Using Micro-Flow Imaging, Archimedes, and Quartz Crystal Microbalance with Dissipation.

Science.gov (United States)

Zheng, Songyan; Puri, Aastha; Li, Jinjiang; Jaiswal, Archana; Adams, Monica

2017-01-01

Micro-flow imaging (MFI) has been used for formulation development for analyzing sub-visible particles. Archimedes, a novel technique for analyzing sub-micron particles, has been considered as an orthogonal method to currently existing techniques. This study utilized these two techniques to investigate the effectiveness of polysorbate (PS-80) in mitigating the particle formation of a therapeutic protein formulation stored in silicone oil-coated pre-filled syringes. The results indicated that PS-80 prevented the formation of both protein and silicone oil particles. In the case of protein particles, PS-80 might involve in the interactions with the hydrophobic patches of protein, air bubbles, and the stressed surfaces of silicone oil-coated pre-filled syringes. Such interactions played a role in mitigating the formation of protein particles. Subsequently, quartz crystal microbalance with dissipation (QCM-D) was utilized to characterize the interactions associated with silicone oil, protein, and PS-80 in the solutions. Based on QCM-D results, we proposed that PS-80 likely formed a layer on the interior surfaces of syringes. As a result, the adsorbed PS-80 might block the leakage of silicone oil from the surfaces to solution so that the silicone oil particles were mitigated at the presence of PS-80. Overall, this study demonstrated the necessary of utilizing these three techniques cooperatively in order to better understand the interfacial role of PS-80 in mitigating the formation of protein and silicone oil particles.

Layering and Ordering in Electrochemical Double Layers

Energy Technology Data Exchange (ETDEWEB)

Liu, Yihua [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States; Kawaguchi, Tomoya [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States; Pierce, Michael S. [Rochester Institute of Technology, School of Physics and Astronomy, Rochester, New York 14623, United States; Komanicky, Vladimir [Faculty of Science, Safarik University, 041 54 Kosice, Slovakia; You, Hoydoo [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States

2018-02-26

Electrochemical double layers (EDL) form at electrified interfaces. While Gouy-Chapman model describes moderately charged EDL, formation of Stern layers was predicted for highly charged EDL. Our results provide structural evidence for a Stern layer of cations, at potentials close to hydrogen evolution in alkali fluoride and chloride electrolytes. Layering was observed by x-ray crystal truncation rods and atomic-scale recoil responses of Pt(111) surface layers. Ordering in the layer is confirmed by glancing-incidence in-plane diffraction measurements.

The effect of crystal orientation on the aluminum anodes of the aluminum-air batteries in alkaline electrolytes

Science.gov (United States)

Fan, Liang; Lu, Huimin; Leng, Jing; Sun, Zegao; Chen, Chunbo

2015-12-01

Recently, aluminum-air (Al-air) batteries have received attention from researchers as an exciting option for safe and efficient batteries. The electrochemical performance of Aluminum anode remains an active area of investigation. In this paper, the electrochemical properties of polycrystalline Al, Al (001), (110) and (111) single crystals are investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in 4 M NaOH and KOH. Hydrogen corrosion rates of the Al anodes are determined by hydrogen collection. Battery performance using the anodes is tested by constant current discharge at 10 mA cm-2. This is the first report showing that the electrochemical properties of Al are closely related to the crystallographic orientation in alkaline electrolytes. The (001) crystallographic plane has good corrosion resistance but (110) is more sensitive. Al (001) single crystals display higher anode efficiency and capacity density. Controlling the crystallographic orientation of the Al anode is another way to improve the performance of Al-air batteries in alkaline electrolytes.

Development of quartz particulate reinforced AA6063 aluminum matrix composites via friction stir processing

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S. Joyson Abraham

2016-12-01

Full Text Available Friction stir processing (FSP has been accepted as a potential method to produce aluminum matrix composites (AMCs without the drawbacks of liquid metallurgy methods. The present work focuses on the development of AMCs reinforced with quartz (SiO2 particles using FSP. Grooves with various dimensions were machined on AA6063 plates and compacted with quartz particles. A single pass FSP was carried out using a combination of optimized process parameters. The volume fraction of quartz particles in the AMCs was varied from 0 to 18 vol.% in steps of 6 vol.%. The developed AA6063/Quartz AMCs were characterized using optical, scanning and transmission electron microscopy. The quartz particles were distributed uniformly in the aluminum matrix irrespective of the location within the stir zone. The grains of the AA6063 were extensively refined by the combination of thermomechanical effect of FSP and the pinning effect of quartz particles. The dispersion of the quartz particles improved the microhardness and wear resistance of the AMCs. The role of quartz particles on the worn surface and wear debris is reported.

Synthesis of electro-optically active polymer composite of poly[2,2'-bis(3,4-ethylenedioxythiophene-alt-fluorene]/hydroxypropyl cellulose showing liquid crystal structure

Directory of Open Access Journals (Sweden)

N. Eguchi

2017-10-01

Full Text Available Electrochemical preparation of a composite consisting of poly[2,2′-bis(3,4-ethylenedioxythiophene-alt-fluorene] and hydroxypropyl cellulose (PEFE/HPC was carried out. We conducted electrochemical polymerization of poly[2,2′-bis(3,4-ethylenedioxythiophene-alt-fluorene] (EFE as a monomer in a lyotropic liquid crystal of HPC. We used an organic solvent instead of water for lyotropic liquid crystal medium to expand the possibility of the range of monomers, although water is usually employed as a solvent for HPC for showing liquid crystallinity. Here, we employed N,N-dimethylformamide (DMF as a solvent for HPC. Electrochemical polymerization in the polymer liquid crystal was carried out to obtain a polymer film with liquid crystal order. The polymer film thus prepared exhibited optical activity. Fourier transfer infrared (FT-IR absorption spectroscopy reveals that the film is a composite consisting of HPC and polymer. The composite PEFE/HPC thus prepared in HPC/DMF system showed electrochromism.

Surface coatings on quartz grains in bentonites and their relevance to human health

International Nuclear Information System (INIS)

Wendlandt, Richard F.; Harrison, Wendy J.; Vaughan, David J.

2007-01-01

The cytotoxicity of quartz in the human lung is recognized to be dependent on both the inherent properties of the silica dust and external factors related to the history of the dust and including the presence of surface contamination. In this study, the physical and chemical surface properties of quartz grains in commercial bentonite deposits from the western (South Dakota) and southern (Alabama) USA were investigated. Measured quartz contents of bentonites range from 1.9 to 8.5 wt% with the <10 μm size fraction comprising 6-45% of this total. Trace element contents (Fe-Ti-Al) of quartz grains from any given bentonite are similar, indicating a single origin for the quartz with little if any contamination from other sources. Surface coatings are pervasive on all quartz grains and resist removal by repeated vigorous washings and reaction with HCl. Textural attributes and XPS and EDS analyses of these coatings are consistent with most being montmorillonite and, less frequently, mixtures of montmorillonite and opaline silica. Opaline silica (opal-A and opal-CT) occurs in two texturally distinct generations: an early massive grain-coating event and as later lepispheres. Montmorillonite coating thicknesses range from <1 μm to more than 10 μm thick. Surfaces of plagioclase, K-feldspar, and biotite grains are conspicuously devoid of montmorillonite coatings, but may show sparse distributions of opal-CT lepispheres. HRTEM has not confirmed a topotactic relationship or atomic structural concordance between montmorillonite coatings and underlying quartz grains. Alternatively, a precursor volcanic glass phase that coats the quartz surfaces during volcanic eruption and/or preferential early precipitation of opaline silica on quartz may provide substrates for development of montmorillonite coatings. Estimations of montmorillonite biodurability under pulmonary pH conditions suggest possible prolonged sequestration of respired bentonite quartz grains from contact with lung

Pyro-Electrochemical Reduction of a Mixture of Rare Earth Oxides and NiO in LiCl molten Salt

Energy Technology Data Exchange (ETDEWEB)

Lee, Min Woo; Jeong, Sang Mun [Department of Chemical Engineering, Chungbuk National University, Cheongju (Korea, Republic of)

2017-06-15

An electrochemical reduction of a mixture of NiO and rare earth oxides has been conducted to increase the reduction degree of rare earth oxides. Cyclic voltammetry (CV) measurement was carried out to determine the electrochemical reduction behavior of the mixed oxide in molten LiCl medium. Constant voltage electrolysis was performed with various supplied charges to understand the mechanism of electrochemical reduction of the mixed oxide as a working electrode. After completion of the electrochemical reduction, crystal structure of the reaction intermediates was characterized by using an X-ray diffraction method. The results clearly demonstrate that the rare earth oxide was converted to RE-Ni intermetallics via co-reduction with NiO.

Polymeric electrodes

Science.gov (United States)

Appel, G.; Mikalo, R.; Henkel, K.; Oprea, A.; Yfantis, A.; Paloumpa, I.; Schmeißer, D.

2000-05-01

We report experiments on conducting polymer polypyrrole leading to sensor applications. The resonance frequency, stability and sensitivity of AT-cut quartz crystals, electrochemically covered with polypyrrole tosylate, were tested under various operating conditions. The interaction of this organic semiconductor with thin metallic films was analysed by photoelectron investigations. Shifts of the valence band spectra during silver deposition are explained by the neutralization of positive charged surface defects. Thus the existence of a space charge region in polypyrrole is demonstrated spectroscopically.

Evaluation of trapping parameters of annealed natural quartz

International Nuclear Information System (INIS)

Zhou, Rui; Wei, Ming-Jian; Song, Bo; Zhang, Yan; Zhao, Qiu-Yue; Pan, Bao-Lin; Li, Teng-Fei

2016-01-01

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_m − T_s_t_o_p 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_m.

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}.

75 FR 30282 - Airworthiness Directives; Quartz Mountain Aerospace, Inc. Model 11E Airplanes

Science.gov (United States)

2010-06-01

... Airworthiness Directives; Quartz Mountain Aerospace, Inc. Model 11E Airplanes AGENCY: Federal Aviation... airworthiness directive (AD) for all Quartz Mountain Aerospace, Inc. Model 11E airplanes. This AD requires you... reference of certain publications listed in this AD. ADDRESSES: Quartz Mountain Aerospace, Inc. is in...

Growth of plutons by incremental emplacement of sheets in crystal-rich host: Evidence from Miocene intrusions of the Colorado River region, Nevada, USA

Science.gov (United States)

Miller, C.F.; Furbish, D.J.; Walker, B.A.; Claiborne, L.L.; Koteas, G.C.; Bleick, H.A.; Miller, J.S.

2011-01-01

crystal-laden host is important in pluton construction. The dominant granite unit of the Spirit Mountain batholith displays only subtle internal contacts. However, ages and elemental zoning in zircons demonstrate a protracted history of almost 2 million years, major fluctuations in T and host melt chemistry, and mixing of strongly contrasting populations of magmatic zircon in single samples. We interpret this to reflect reactivation of rigid sponge and mush and entrainment of earlier-formed crystals, and we infer that this was in response to granitic replenishment. Much of the smaller Aztec Wash pluton comprises interlayered cumulate-textured quartz monzonite and mafic sheets. The latest phase of pluton emplacement is marked by numerous thick, fine-grained granite "sills" that intruded the subhorizontal quartz monzonite sheets. Contacts between granite and quartz monzonite are "soft," highly irregular on cm-dm scale with coarse xenocrysts from the quartz monzonite entrained in the fine-grained granite. We interpret the granite replenishments to have spread laterally within crystal-rich, melt-bearing quartz monzonite beneath rigid mafic sheets. In this case, clear evidence for the emplacement process is fortuitously preserved because the granite was emplaced in the waning stage of the thermal lifetime of the pluton, and because the mafic sheets enhance the strength contrast and make the geometry more visible. Similar "sills" of fine-grained granite were also preserved during the late stages of the history of the Spirit Mountain batholith. ?? 2009 Elsevier B.V.

Magnetic field-assisted electrochemical discharge machining

International Nuclear Information System (INIS)

Cheng, Chih-Ping; Mai, Chao-Chuang; Wu, Kun-Ling; Hsu, Yu-Shan; Yan, Biing-Hwa

2010-01-01

Electrochemical discharge machining (ECDM) is an effective unconventional method for micromachining in non-conducting materials, such as glass, quartz and some ceramics. However, since the spark discharge performance becomes unpredictable as the machining depth increases, it is hard to achieve precision geometry and efficient machining rate in ECDM drilling. One of the main factors for this is the lack of sufficient electrolyte flow in the narrow gap between the tool and the workpiece. In this study a magnetohydrodynamic (MHD) convection, which enhances electrolyte circulation has been applied to the ECDM process in order to upgrade the machining accuracy and efficiency. During electrolysis in the presence of a magnetic field, the Lorenz force induces the charged ions to form a MHD convection. The MHD convection then forces the electrolyte into movement, thus enhancing circulation of electrolyte. Experimental results show that the MHD convection induced by the magnetic field can effectively enhance electrolyte circulation in the micro-hole, which contributes to higher machining efficiency. Micro-holes in glass with a depth of 450 µm are drilled in less than 20 s. At the same time, better electrolyte circulation can prevent deterioration of gas film quality with increasing machining depth, while ensuring stable electrochemical discharge. The improvement in the entrance diameter thus achieved was 23.8% while that in machining time reached 57.4%. The magnetic field-assisted approach proposed in the research does not require changes in the machining setup or electrolyte but has proved to achieve significant enhancement in both accuracy and efficiency of ECDM.

Metodologia para o crescimento de esferas monocristalinas de metais nobres A methodology for the growing of single crystal spheres of noble metals

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Luiz H. Dall'Antonia

1999-09-01

Full Text Available This paper describes in detail a technique employed to grow quasi-spherical single crystals of noble metals for electrochemical applications, using platinum as an example. The metal beads were formed by melting the extremity of a wire in an oxygen / butane flame. X-ray techniques were used to check the crystallization and to determine the orientation of the crystals. Treatment with a pure hydrogen flame followed by a cooling procedure in a hydrogen / argon atmosphere were used for conditioning the well-defined platinum single crystal surfaces. Finally, electrochemical characterization of the Pt(111, Pt(110 and Pt(100 surfaces was done in diluted sulfuric acid solution in the hydrogen adsorption / desorption potential region.

First-principles simulation of Raman spectra and structural properties of quartz up to 5 GPa

International Nuclear Information System (INIS)

Liu Lei; Lv Chao-Jia; Yi Li; Liu Hong; Du Jian-Guo; Zhuang Chun-Qiang

2015-01-01

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 (dν i /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. (paper)

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.

The Effect of Quartz on the Flotation of Fine Wolframite with Octyl Hydroxamic Acid

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Qingyou Meng

2017-09-01

Full Text Available The influence of quartz on the flotation of fine wolframite using octyl hydroxamic acid (OHA as the collector was investigated by micro-flotation tests, inductively coupled plasma (ICP measurements, adsorption experiments, zeta potential, and Fourier transform infrared spectroscopy (FT-IR analysis. Micro-flotation tests showed that a large difference in floatability existed between fine wolframite and quartz in the pH range of 7.0 to 10.0. However, in a synthetic mixture, the flotation separation of fine wolframite from quartz became more difficult as the particle size of the latter decreased. When a dissolved solution of wolframite was used as the flotation medium, quartz floatability improved significantly. Zeta potentials of quartz particles shifted positively in the dissolved solution of wolframite compared to distilled water, especially at a pH level of 7.0–10.0, which was attributed to the metal ions dissolved from the wolframite being adsorbed onto the quartz surface. The surface activation of quartz led to an increase in the OHA adsorption and made the surface hydrophobic. FT-IR analysis further demonstrated that OHA could adsorb onto the activated quartz surface through a dominantly chemical process.

Hydrothermal synthesis, characterization, formation mechanism and electrochemical property of V3O7.H2O single-crystal nanobelts

International Nuclear Information System (INIS)

Zhang Yifu; Liu Xinghai; Xie Guangyong; Yu Lei; Yi Shengping; Hu Mingjie; Huang Chi

2010-01-01

Single-crystal V 3 O 7 .H 2 O nanobelts have been successfully synthesized in a large-scale by ethanol reducing of the commercial V 2 O 5 powder via a facile hydrothermal approach, without any templates and surfactants. The as-prepared V 3 O 7 .H 2 O nanobelts are up to several tens of micrometers in length, about 100 nm in width and about 20 nm in thickness in average, respectively. The 'Hydrating-Reducing-Exfoliating-Splitting' (HRES) mechanism was proposed to describe the formation of the V 3 O 7 .H 2 O nanobelts. In our research progress, it was found that the ratio of EtOH/H 2 O, the reaction time and categories of the reducing agents had significant effects on the morphology and composition of as-obtained products. Furthermore, the electrochemical properties of V 3 O 7 .H 2 O nanobelts were preformed and the results revealed that a lithium battery using those nanobelts as the positive electrode exhibited a high initial discharge capacity of 373 mAh/g.

Electrochemistry of Hemin on Single-Crystal Au(111)-electrode Surfaces

DEFF Research Database (Denmark)

Zhang, Ling; Ulstrup, Jens; Zhang, Jingdong

adsorption on well-defined single-crystal Au(111)-electrode surfaces using electrochemistry combined with scanning tunnelling microscopy under electrochemical control. Hemin gives two voltammetric peaks assigned to adsorbed monomers and dimmers (Fig. 1B). In situ STM shows that hemin self...

Apatite-brannerite-pitchblende association in hydrothermal quartz veins

International Nuclear Information System (INIS)

Brodin, B.V.; Mel'nikova, A.M.; Osipov, B.S.; Pavlov, E.G.

1976-01-01

A study into the vein quartz mineralization confined to the tectonic zones of crush and silicification in sedimentary-igneous rocks of the lower Paleozoic has been made. The physicochemical characteristics of minerals were studied by way of optical and electron microscopy, chemical, laser-microspectral and X-ray structural analyses, microprobing and alpha-microradiography. 3 mineral associations have been discriminated, representative of the sequence of hydrothermal mineralization. An unusual parogenesis of pitchblende and brannerite with apatite, xenotime and more recent goethite has been revealed. The results are indicative of a medium-low-temperature hydrothermal process occurring at the final stages of formation of uraniferrous quartz veins. By composition and mineralization sequence, the latters are close to low- and medium-temperature uranium-quartz-chlorite-hydromica formations with apatite, coffinite, brannerite and pitchblende. The weak initial metamictization of goethite in veins 80 to 100 million years old is due to the radioactive effect of the submicroscopic radioactive mineral impurity on the crystalline lattice

Face-centered-cubic lithium crystals formed in mesopores of carbon nanofiber electrodes.

Science.gov (United States)

Lee, Byoung-Sun; Seo, Jong-Hyun; Son, Seoung-Bum; Kim, Seul Cham; Choi, In-Suk; Ahn, Jae-Pyoung; Oh, Kyu Hwan; Lee, Se-Hee; Yu, Woong-Ryeol

2013-07-23

In the foreseeable future, there will be a sharp increase in the demand for flexible Li-ion batteries. One of the most important components of such batteries will be a freestanding electrode, because the traditional electrodes are easily damaged by repeated deformations. The mechanical sustainability of carbon-based freestanding electrodes subjected to repeated electrochemical reactions with Li ions is investigated via nanotensile tests of individual hollow carbon nanofibers (HCNFs). Surprisingly, the mechanical properties of such electrodes are improved by repeated electrochemical reactions with Li ions, which is contrary to the conventional wisdom that the mechanical sustainability of carbon-based electrodes should be degraded by repeated electrochemical reactions. Microscopic studies reveal a reinforcing mechanism behind this improvement, namely, that inserted Li ions form irreversible face-centered-cubic (FCC) crystals within HCNF cavities, which can reinforce the carbonaceous matrix as strong second-phase particles. These FCC Li crystals formed within the carbon matrix create tremendous potential for HCNFs as freestanding electrodes for flexible batteries, but they also contribute to the irreversible (and thus low) capacity of HCNFs.

Dependence of TL-property changes of natural quartzes on aluminium contents accompanied by thermal annealing treatment

International Nuclear Information System (INIS)

Hashimoto, T.; Sakaue, S.; Aoki, H.; Ichino, M.

1994-01-01

The TL properties were investigated using both an IPDA (Intensified Photo-Diode Array) spectrometric system and a TLCI (Thermoluminescence Colour Image) method after thermal annealing treatment at several temperatures. An apparent colour change from original blue- (BTL) to red-TL(RTL) has unexpectedly occurred in a Z-cut slice of Madagascar quartz, after an annealing treatment around 1000 o C. From the TL-colour change studies of the Z-cut slice, it was confirmed that original BTL intensities are inversely proportional to the Al contents; the TLCI-patterns of the original or annealed Z-cut slice gave stripe patterns corresponding to Al impurity contents along the crystal growth direction particularly yielding an intense appearance of RTL on higher Al contents after the annealing treatment. This changeability of TL-colour towards RTL after thermal annealing treatment was found to be intimately correlated with the square of Al concentrations, although BTL clearly changed as linearly proportional to Al impurity contents. Finally, the cleavage of Al-O-Al bonds or some sites in the vicinity of Al-O-Al bonds were plausibly considered to play an important role for the formation of RTL colour centres in natural quartzes as a result of the operation of high temperature effects. (Author)

OSL and IRSL characteristics of quartz and feldspar from southern California, USA

International Nuclear Information System (INIS)

Lawson, Michael J.; Roder, Belinda J.; Stang, Dallon M.; Rhodes, Edward J.

2012-01-01

Southern California comprises of a wide range of diverse landscapes and environments, from high mountains with glacial and periglacial sediments to deserts with large sand dunes, extensive alluvial fans and ephemeral playas. Highly active tectonic processes has exposed ancient (c. 2 Ga) plutonic and metamorphic basement from deep within the crust, while similar Palaeozoic, Mesozoic and Cenozoic rocks are also common. A rich array of volcanic lithologies extending into the late Quaternary complement many thick sedimentary sequences that formed in equally diverse ancient environments typical of an accreting active continental margin. In some locations, notably in the Coachella Valley close to Palm Springs and the Salton Sea, low OSL sensitivity and poor characteristics restrict the application of the quartz SAR protocol to date late Pleistocene and Holocene fluvial sediments. In other locations such as the Malibu coastline, high sensitivity of the quartz OSL signal is observed, despite local source rocks being dominated by volcanic lithologies. Problems of poor quartz characteristics, along with uncertainty in predicting quartz OSL behavior for future dating campaigns poses a significant problem for projects, in particular for neotectonic contexts. While K-feldspar has been used extensively to date eolian and fluvial sediments in southern California, little information regarding signal stability is available. We explore the characteristics of both quartz and feldspar sub-samples from eolian, fluvial, lacustrine environments, in order to help develop mineral selection criteria for optical dating applications and clarify these issues. The importance of radiation quenching in quartz grains recently eroded from bedrock and the role of fires in enhancing OSL sensitivity are considered. The relative bleachability of quartz and feldspar fractions, along with thermal stability considerations is discussed. A simple test for quartz OSL signal contamination based on thermal

Microscopy and Cathodoluminescence Spectroscopy Characterization of Quartz Exhibiting Different Alkali-Silica Reaction Potential.

Science.gov (United States)

Kuchařová, Aneta; Götze, Jens; Šachlová, Šárka; Pertold, Zdeněk; Přikryl, Richard

2016-02-01

Different quartz types from several localities in the Czech Republic and Sweden were examined by polarizing microscopy combined with cathodoluminescence (CL) microscopy, spectroscopy, and petrographic image analysis, and tested by use of an accelerated mortar bar test (following ASTM C1260). The highest alkali-silica reaction potential was indicated by very fine-grained chert, containing significant amounts of fine-grained to cryptocrystalline matrix. The chert exhibited a dark red CL emission band at ~640 nm with a low intensity. Fine-grained orthoquartzites, as well as fine-grained metamorphic vein quartz, separated from phyllite exhibited medium expansion values. The orthoquartzites showed various CL of quartz grains, from blue through violet, red, and brown. Two CL spectral bands at ~450 and ~630 nm, with various intensities, were detected. The quartz from phyllite displayed an inhomogeneous dark red CL with two CL spectral bands of low intensities at ~460 and ~640 nm. The massive coarse-grained pegmatite quartz from pegmatite was assessed to be nonreactive and displayed a typical short-lived blue CL (~480 nm). The higher reactivity of the fine-grained hydrothermal quartz may be connected with high concentrations of defect centers, and probably with amorphized micro-regions in the quartz, respectively; indicated by a yellow CL emission (~570 nm).

External micro-PIXE analysis of fluid inclusions: Test of the LABEC facility on samples of quartz veins from Apuan Alps (Italy)

International Nuclear Information System (INIS)

Massi, M.; Calusi, S.; Giuntini, L.; Ruggieri, G.; Dini, A.

2008-01-01

Fluid inclusions are small portions, usually smaller than 100 μm, of fluid trapped within minerals during or after growth. Their characteristics provide therefore fundamental information on nature and evolution of fluids present in the past in different geological environments. At the LABEC laboratory in Firenze, high-salinity fluid inclusions in quartz crystals, coming from the Apuan Alps metamorphic complex, were analysed at the external scanning microbeam. Results, although still preliminary, have already provided us with hints on fluid-rock interaction processes during the metamorphism of the Apuan Alps

External micro-PIXE analysis of fluid inclusions: Test of the LABEC facility on samples of quartz veins from Apuan Alps (Italy)

Energy Technology Data Exchange (ETDEWEB)

Massi, M. [Dipartimento di Fisica dell' Universita and INFN sezione di Firenze, via G. Sansone 1, Sesto Fiorentino 50019, Firenze (Italy)], E-mail: massi@fi.infn.it; Calusi, S. [Dipartimento di Fisica dell' Universita and INFN sezione di Torino, via P. Giuria 1, 10125 Torino (Italy); Giuntini, L. [Dipartimento di Fisica dell' Universita and INFN sezione di Firenze, via G. Sansone 1, Sesto Fiorentino 50019, Firenze (Italy); Ruggieri, G. [CNR - Istituto di Geoscienze e Georisorse sezione di Firenze, via G. La Pira 4, Firenze 50121 (Italy); Dini, A. [CNR - Istituto di Geoscienze e Georisorse sezione di Pisa, via G. Moruzzi 1, Pisa 56124 (Italy)

2008-05-15

Fluid inclusions are small portions, usually smaller than 100 {mu}m, of fluid trapped within minerals during or after growth. Their characteristics provide therefore fundamental information on nature and evolution of fluids present in the past in different geological environments. At the LABEC laboratory in Firenze, high-salinity fluid inclusions in quartz crystals, coming from the Apuan Alps metamorphic complex, were analysed at the external scanning microbeam. Results, although still preliminary, have already provided us with hints on fluid-rock interaction processes during the metamorphism of the Apuan Alps.

The effects to the structure and electrochemical behavior of zinc phosphate conversion coatings with ethanolamine on magnesium alloy AZ91D

International Nuclear Information System (INIS)

Li Qing; Xu Shuqiang; Hu Junying; Zhang Shiyan; Zhong Xiankang; Yang Xiaokui

2010-01-01

This paper discussed a zinc phosphate conversion coating formed on magnesium alloy AZ91D from the phosphating bath with varying amounts of ethanolamine (MEA). The effects of MEA on the form, structure, phase composition and electrochemical behavior of the phosphate coatings were examined using an scanning electron microscopy (SEM), X-ray diffraction (XRD) potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) measurements. Interpretations of the electrical elements of the equivalent circuit were obtained from the SEM structure of the coatings, assumed to be formed of two layers: an outer porous crystal layer and an inner flat amorphous layer. The result showed that adding MEA refined the microstructure of the crystal layer and that the phosphate coating, derived at the optimal content of 1.2 g/L, with the most uniform and compact outer crystal layer provided the best corrosion protection.

Surface structured platinum electrodes for the electrochemical reduction of carbon dioxide in imidazolium based ionic liquids.

Science.gov (United States)

Hanc-Scherer, Florin A; Montiel, Miguel A; Montiel, Vicente; Herrero, Enrique; Sánchez-Sánchez, Carlos M

2015-10-07

The direct CO2 electrochemical reduction on model platinum single crystal electrodes Pt(hkl) is studied in [C2mim(+)][NTf2(-)], a suitable room temperature ionic liquid (RTIL) medium due to its moderate viscosity, high CO2 solubility and conductivity. Single crystal electrodes represent the most convenient type of surface structured electrodes for studying the impact of RTIL ion adsorption on relevant electrocatalytic reactions, such as surface sensitive electrochemical CO2 reduction. We propose here based on cyclic voltammetry and in situ electrolysis measurements, for the first time, the formation of a stable adduct [C2mimH-CO2(-)] by a radical-radical coupling after the simultaneous reduction of CO2 and [C2mim(+)]. It means between the CO2 radical anion and the radical formed from the reduction of the cation [C2mim(+)] before forming the corresponding electrogenerated carbene. This is confirmed by the voltammetric study of a model imidazolium-2-carboxylate compound formed following the carbene pathway. The formation of that stable adduct [C2mimH-CO2(-)] blocks CO2 reduction after a single electron transfer and inhibits CO2 and imidazolium dimerization reactions. However, the electrochemical reduction of CO2 under those conditions provokes the electrochemical cathodic degradation of the imidazolium based RTIL. This important limitation in CO2 recycling by direct electrochemical reduction is overcome by adding a strong acid, [H(+)][NTf2(-)], into solution. Then, protons become preferentially adsorbed on the electrode surface by displacing the imidazolium cations and inhibiting their electrochemical reduction. This fact allows the surface sensitive electro-synthesis of HCOOH from CO2 reduction in [C2mim(+)][NTf2(-)], with Pt(110) being the most active electrode studied.

Crystallization characteristics of iron-rich glass ceramics prepared from nickel slag and blast furnace slag

Science.gov (United States)

Wang, Zhong-Jie; Ni, Wen; Li, Ke-Qing; Huang, Xiao-Yan; Zhu, Li-Ping

2011-08-01

The crystallization process of iron-rich glass-ceramics prepared from the mixture of nickel slag (NS) and blast furnace slag (BFS) with a small amount of quartz sand was investigated. A modified melting method which was more energy-saving than the traditional methods was used to control the crystallization process. The results show that the iron-rich system has much lower melting temperature, glass transition temperature ( T g), and glass crystallization temperature ( T c), which can result in a further energy-saving process. The results also show that the system has a quick but controllable crystallization process with its peak crystallization temperature at 918°C. The crystallization of augite crystals begins from the edge of the sample and invades into the whole sample. The crystallization process can be completed in a few minutes. A distinct boundary between the crystallized part and the non-crystallized part exists during the process. In the non-crystallized part showing a black colour, some sphere-shaped augite crystals already exist in the glass matrix before samples are heated to T c. In the crystallized part showing a khaki colour, a compact structure is formed by augite crystals.

Constraints on the depth of generation and emplacement of a magmatic epidote-bearing quartz diorite pluton in the Coast Plutonic Complex, British Columbia

Science.gov (United States)

Chang, J.M.; Andronicos, C.L.

2009-01-01

Petrology and P-T estimates indicate that a magmatic epidote-bearing quartz diorite pluton from Mt. Gamsby, Coast Plutonic Complex, British Columbia, was sourced at pressures below ???1.4 GPa and cooled nearly isobarically at ???0.9 GPa. The P-T path indicates that the magma was within the stability field of magmatic epidote early and remained there upon final crystallization. The pluton formed and crystallized at depths greater than ???30 km. REE data indicate that garnet was absent in the melting region and did not fractionate during crystallization. This suggests that the crust was less than or equal to ???55 km thick at 188 Ma during the early phases of magmatism in the Coast Plutonic Complex. Late Cretaceous contractional deformation and early Tertiary extension exhumed the rocks to upper crustal levels. Textures of magmatic epidote and other magmatic phases, combined with REE data, can be important for constraining the P-T path followed by magmas. ?? 2009 Blackwell Publishing Ltd.

Absorption and luminescence of crystalline quartz under electron nanosecond irradiation

Energy Technology Data Exchange (ETDEWEB)

Gritsenko, B P; Lisitsyn, V M; Stepanchuk, V N [Tomskij Politekhnicheskij Inst. (USSR)

1981-02-01

The purpose of the study is continuation of investigations of principal regularities of production and destruction of short-lived defects in quartz and accompanying luminescence under electron pulse irradiation. For investigation purposes samples of crystalline synthetic quartz have been used. The irradiation has been performed at 80-400 K temperatures by means of an electron pulse accelerator with parameters: electron flow pulse duration 10 ns, pulse current density up to 1000 A/cm/sup 2/, electron mean energy 200 keV. Temperature-time characteristics of absorption and luminescence spectrum are studied. It has been found that quartz irradiation by electron pulses of nanosecond duration leads to appearance of short-lived bands of optical absorption at 4.1 and 5.15 eV to which by kinetic parameters correspond luminescence bands at 2.6 and 3.1 eV, respectively. The enumerated absorption bands are induced by quartz irradiation independently of the prehistory and phase state of the sample and are caused obviously by intrinsic radiation defects. Possible models of such defects are suggested.

Semiconducting icosahedral boron arsenide crystal growth for neutron detection

Science.gov (United States)

Whiteley, C. E.; Zhang, Y.; Gong, Y.; Bakalova, S.; Mayo, A.; Edgar, J. H.; Kuball, M.

2011-03-01

Semiconducting icosahedral boron arsenide, B12As2, is an excellent candidate for neutron detectors, thermoelectric converters, and radioisotope batteries, for which high quality single crystals are required. Thus, the present study was undertaken to grow B12As2 crystals by precipitation from metal solutions (nickel) saturated with elemental boron (or B12As2 powder) and arsenic in a sealed quartz ampoule. B12As2 crystals of 10-15 mm were produced when a homogeneous mixture of the three elements was held at 1150 °C for 48-72 h and slowly cooled (3.5 °C/h). The crystals varied in color and transparency from black and opaque to clear and transparent. X-ray topography (XRT), and elemental analysis by energy dispersive X-ray spectroscopy (EDS) confirmed that the crystals had the expected rhombohedral structure and chemical stoichiometry. The concentrations of residual impurities (nickel, carbon, etc.) were low, as measured by Raman spectroscopy and secondary ion mass spectrometry (SIMS). Additionally, low etch-pit densities (4.4×107 cm-2) were observed after etching in molten KOH at 500 °C. Thus, the flux growth method is viable for growing large, high-quality B12As2 crystals.

Synthesis, characterization, single crystal X-ray determination, fluorescence and electrochemical studies of new dinuclear nickel(II) and oxovanadium(IV) complexes containing double Schiff base ligands

Science.gov (United States)

Shafaatian, Bita; Ozbakzaei, Zahra; Notash, Behrouz; Rezvani, S. Ahmad

2015-04-01

A series of new bimetallic complexes of nickel(II) and vanadium(IV) have been synthesized by the reaction of the new double bidentate Schiff base ligands with nickel acetate and vanadyl acetylacetonate in 1:1 M ratio. In nickel and also vanadyl complexes the ligands were coordinated to the metals via the imine N and enolic O atoms. The complexes have been found to possess 1:1 metals to ligands stoichiometry and the molar conductance data revealed that the metal complexes were non-electrolytes. The nickel and vanadyl complexes exhibited distorted square planar and square pyramidal coordination geometries, respectively. The emission spectra of the ligands and their complexes were studied in methanol. Electrochemical properties of the ligands and their metal complexes were also investigated in DMSO solvent at 150 mV s-1 scan rate. The ligands and metal complexes showed both quasi-reversible and irreversible processes at this scan rate. The Schiff bases and their complexes have been characterized by FT-IR, 1H NMR, UV/Vis spectroscopies, elemental analysis and conductometry. The crystal structure of the nickel complex has been determined by single crystal X-ray diffraction.

Quartz-Amethyst Hosted Hydrocarbon-Bearing Fluid Inclusions from the Green Ridge Breccia in the Snoqualmie Granite, North Cascades, WA, USA