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Sample records for chromium-doped potassium niobate

  1. Self-focusing in chromium-doped potassium niobate single ceramic crystal

    Energy Technology Data Exchange (ETDEWEB)

    Castillo T, J.; Gonzalez M, S.; Aguirre L, A.; Hernandez, M.B.; Aguilar M, J.A. [Instituto de Fisica y Matematicas, Universidad Tecnologica de la Mixteca, 69000, Huajuapan de Leon, Oaxaca (Mexico); Hernandez A, J. [lFUNAM, PO Box 20-364, 01000 Mexico, DF (Mexico)]. e-mail: jaimec@mixteco.utm.mx

    2006-07-01

    The self-focusing and nonlinear optical absorption in a chromium-doped potassium niobate single ceramic crystal have been investigated. The third-order electric susceptibility X{sup (3)} at continuous 532 nm radiation is estimated based on a band transport model describing photo refractive properties for this electro-optic material. An anisotropic behavior on its nonlinear optical absorption properties has also been observed due to the presence of chromium ions. (Author)

  2. Development of a new photorefractive and photovoltaic potassium niobate crystal

    Science.gov (United States)

    Evans, D. R.; Basun, S. A.; Seim, J. M.

    2005-03-01

    Photovoltaic measurements have been made on a new doped potassium niobate crystal that yields significantly larger photovoltaic fields than other doped potassium niobate crystals. Contra-directional two-beam coupling efficiencies and Raman spectroscopy measurements have also been conducted, which show major differences with respect to the published results for other doped potassium niobate materials.

  3. Transformation of potassium Lindquist hexaniobate to various potassium niobates: solvothermal synthesis and structural evolution mechanism.

    Science.gov (United States)

    Kong, Xingang; Hu, Dengwei; Wen, Puhong; Ishii, Tomohiko; Tanaka, Yasuhiro; Feng, Qi

    2013-06-07

    This paper introduces the formation reactions and reaction mechanisms of a series of potassium niobates from a potassium salt of the Lindquist hexaniobate [Nb6O19](8-) ion under solvothermal conditions. The structure and particle morphology of the potassium niobate product can be controlled easily with the reaction solution alkalinity using this solvothermal process. KNb3O8 with a plate-like morphology, K4Nb6O17·4.5H2O with a plate-like morphology, a new phase of K2Nb2O6·H2O with fibrous morphology, KNbO3 perovskites with cubic morphology are obtained at pH = 5.5, and in 0.3, 0.5, 1.0 mol L(-1) KOH solutions at 230 °C, respectively. The reaction conditions are much milder than those in the normal hydrothermal process. Furthermore, the K2Nb2O6·H2O fibers can be topotactically transformed into KNbO3 fibers, Nb2O5 fibers after H(+)-exchange-treatment, and LiNbO3 fibers after Li(+)-exchange-treatment by heat-treatments at 730, 560, and 520 °C, respectively. The formation reaction and structure of these potassium niobates were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), energy-dispersive spectroscopy (EDS), Raman spectra and TG-DTA. The formation mechanism of this series of potassium niobates from the [Nb6O19](8-) precursor is systematically explained via the correlation between the octahedrons [NbO6] sharing forms in the precursor structure and in the product structures.

  4. Highly accelerated lifetime testing of potassium sodium niobate thin films

    Science.gov (United States)

    Zhu, Wanlin; Akkopru-Akgun, Betul; Trolier-McKinstry, Susan

    2017-11-01

    Highly accelerated lifetime tests of 2 and 3 μm thick potassium sodium niobate [(K0.5, Na0.5)NbO3, KNN] films with different thicknesses were measured under electric fields ranging from 160 to 350 kV/cm and temperatures ranging from 90 to 210 °C. The medium time to failure (t50) was determined from a lognormal distribution plot of failure times of up to 22 electrodes per measurement condition. The activation energy (Ea) for failure was 0.74 ± 0.04 eV and 0.92 ± 0.05 eV for the 2 μm and 3 μm KNN films, respectively. The voltage acceleration factor was 3.5 ± 0.34 for the 3 μm film. But the electric field dependence of t50 for the 2 μm film showed two regions with similar N, 6.67 and 6.94 ± 0.23, respectively. Energy-dispersive X-ray spectroscopy was employed to investigate the Na+ and K+ ion distributions in KNN films.

  5. Preparation of plate-like potassium sodium niobate particles by hydrothermal method

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    Zhang, Fan [School of Materials Science and Engineering, Shenyang University of Chemical Technology, Shenyang 110142 (China); Bai, Shan [School of Materials Science and Engineering, Shenyang University of Chemical Technology, Shenyang 110142 (China); Department of Intelligent Systems Design Engineering, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398 (Japan); Karaki, Tomoaki [Department of Intelligent Systems Design Engineering, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398 (Japan)

    2011-05-15

    Potassium sodium niobate (K,Na)NbO{sub 3} (KNN) particles with a plate-like morphology were prepared. First, an unknown potassium sodium niobate hydrate particles with 150-nm thickness and 1500-nm width were synthesised by a hydrothermal method. After calcining these particles at 450 C, plate-like KNN particles were obtained, which were expected to be used as templates for KNN textured ceramics. It was found that sodium dodecyl-benzene-sulfonate (SDBS) acting as surfactant played an important role in controlling the morphology of the particles in the hydrothermal process. The SDBS surfactant-assisted hydrothermal synthesis is feasible for the mass production of plate-like alkaline niobate template particles. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Major improvements of the photorefractive and photovoltaic properties in potassium niobate

    Science.gov (United States)

    Evans, D. R.; Cook, G.; Carns, J. L.; Saleh, M. A.; Basun, S. A.; Seim, J. M.; Mizell, G. J.

    2006-01-01

    Optical and electrical measurements have been made on a new codoped potassium niobate crystal (KNbO3:Fe,Ag) that yields a significant enhancement of the photorefractive and photovoltaic effects when compared with the published results for singly doped potassium niobate crystals. The codoped Ag impurity enters the K site, rather than the typical Nb site, thus changing the local field in the lattice. It is believed that Fe perturbed by the Ag in the K site is responsible for an enhancement of the linear absorption and photocurrent, as well as a probable increase in the effective trap density. An enhanced trap density is likely the cause of the increased photorefractive counterpropagating two-beam coupling efficiency.

  7. Porosity Dependence of Piezoelectric Properties for Porous Potassium Niobate System Ceramics

    Science.gov (United States)

    Wada, S.; Mase, Y.; Shimizu, S.; Maeda, K.; Fujii, I.; Nakashima, K.; Pulpan, P.; Miyajima, N.

    2011-10-01

    Porous potassium niobate (KNbO3, KN) system ceramics were prepared by a conventional sintering method using carbon black (CB) nanoparticles. First, KN nanoparticles with a size of 100 nm was mixed with CB nanoparticles and binder using ball milling with ethanol. The mixture was dried, and pressed into pellets using uniaxial pressing. After binder burnout, these ceramics was sintered in air. Their piezoelectric properties were measured and discussed a relationship between porosity and piezoelectric properties. As the results, with increasing porosity, piezoelectric g33 constant increased significantly, which suggested that porous ceramics were effective for stress sensor application.

  8. Understanding the optical and electrical properties of a new photorefractive potassium niobate crystal

    Energy Technology Data Exchange (ETDEWEB)

    Evans, D.R. [Air Force Research Laboratory, Materials and Manufacturing Directorate Wright-Patterson Air Force Base, OH 45433 (United States)]. E-mail: dean.evans@wpafb.af.mil; Cook, G. [Air Force Research Laboratory, Materials and Manufacturing Directorate Wright-Patterson Air Force Base, OH 45433 (United States); Universal Technology Corporation, 1270 N. Fairfield Road, Dayton, OH 45432 (United States); Carns, J.L. [Air Force Research Laboratory, Materials and Manufacturing Directorate Wright-Patterson Air Force Base, OH 45433 (United States); Anteon Corporation, 5100 Springfield Pike Suite 509, Dayton, OH 45431 (United States); Saleh, M.A. [Air Force Research Laboratory, Materials and Manufacturing Directorate Wright-Patterson Air Force Base, OH 45433 (United States); UES, Inc., 4401 Dayton-Xenia Road, Dayton, OH 45432 (United States); Basun, S.A. [A. F. Ioffe Physico-Technical Institute, Polytechnicheskaya 26, 194021, St. Petersburg (Russian Federation); Seim, J.M. [VLOC, 7826 Photonics Drive, New Port Richey, FL 34655 (United States); Mizell, G.J. [VLOC, 7826 Photonics Drive, New Port Richey, FL 34655 (United States)

    2006-07-15

    Optical and electrical measurements have been made on a new codoped potassium niobate crystal that yields a significant increase in linear absorption, photocurrent, and photorefractive beam coupling efficiency. The Ag impurity enters the K site, changing the local field in the lattice. The Fe in the Nb site, perturbed by the replacement of the next near-neighbor K with Ag, is responsible for the enhanced linear and nonlinear properties. The modified material parameters result in an increase of the photorefractive counter-propagating two-beam coupling efficiency.

  9. Potassium Niobate Nanolamina: A Promising Adsorbent for Entrapment of Radioactive Cations from Water

    OpenAIRE

    Sun, Jin; Yang, Dongjiang; Sun, Cuihua; Liu, Long; Yang, Shuanglei; Jia, Yi; Cai, Rongsheng; Yao, Xiangdong

    2014-01-01

    Processing and managing radioactive waste is a great challenge worldwide as it is extremely difficult and costly; the radioactive species, cations or anions, leaked into the environment are a serious threat to the health of present and future generations. We report layered potassium niobate (K4Nb6O17) nanolamina as adsorbent to remove toxic Sr2+, Ba2+ and Cs+ cations from wastewater. The results show that K4Nb6O17 nanolamina can permanently confine the toxic cations within the interlayer spac...

  10. Potassium Niobate Nanolamina: A Promising Adsorbent for Entrapment of Radioactive Cations from Water

    Science.gov (United States)

    Sun, Jin; Yang, Dongjiang; Sun, Cuihua; Liu, Long; Yang, Shuanglei; (Alec) Jia, Yi; Cai, Rongsheng; Yao, Xiangdong

    2014-12-01

    Processing and managing radioactive waste is a great challenge worldwide as it is extremely difficult and costly; the radioactive species, cations or anions, leaked into the environment are a serious threat to the health of present and future generations. We report layered potassium niobate (K4Nb6O17) nanolamina as adsorbent to remove toxic Sr2+, Ba2+ and Cs+ cations from wastewater. The results show that K4Nb6O17 nanolamina can permanently confine the toxic cations within the interlayer spacing via a considerable deformation of the metastable layered structure during the ion exchange process. At the same time, the nanolaminar adsorbent exhibits prompt adsorption kinetics, high adsorption capacity and selectivity, and superior acid resistance. These merits make it be a promising material as ion exchanger for the removal of radioactive cations from wastewater.

  11. Modification of both d33 and TC in a potassium-sodium niobate ternary system.

    Science.gov (United States)

    Wu, Bo; Wu, Jiagang; Xiao, Dingquan; Zhu, Jianguo

    2015-12-28

    In this work, we simultaneously achieved a giant d33 and a high TC in a lead-free piezoelectric ternary system of (1-x-y)K0.48Na0.52NbO3-xBiFeO3-yBi0.5Na0.5ZrO3 {(1-x-y)KNN-xBF-yBNZ}. Owing to the rhombohedral-orthorhombic-tetragonal (R-O-T) phase coexistence and the enhanced dielectric and ferroelectric properties, the ceramics with a composition of (x = 0.006, y = 0.04) show a giant d33 of ∼428 pC N(-1) together with a TC of ∼318 °C, thereby proving that the design of ternary systems is an effective way to achieve both high d33 and high TC in KNN-based materials. In addition, a good thermal stability for piezoelectricity was also observed in these ceramics (e.g., d33 > 390 pC N(-1), T ≤ 300 °C). This is the first time such a good comprehensive performance in potassium-sodium niobate materials has been obtained. As a result, we believe that this type of material system with both giant d33 and high TC is a promising candidate for high-temperature piezoelectric devices.

  12. Effect of powder processing conditions on the electromechanical properties of lithium doped potassium sodium niobate

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    Ebru Mensur-Alkoy

    2016-11-01

    Full Text Available Lithium doped potassium sodium niobate ceramics with (K0.50−x/2Na0.50−x/2LixNbO3 composition where x = 0.04 and 0.07 were fabricated by solid state calcination and pressureless sintering methods. However, two different powder processing and calcination routes were used in this study and their effect on the structural and electrical properties were investigated and discussed. The routes were namely loose calcination and compact calcination. A general trend of decreasing grain size was observed in the sintered ceramics prepared from these powders. The most drastic effect was observed on the electromechanical properties of the samples, where the maximum strain of 7% lithium modified sample under an E-field of 50 kV/cm was increased from 0.09% to 0.12% by changing processing route. Furthermore, hysteretic behavior of the strain was found to decrease. This tendency was also valid for ferroelectric hysteresis property, with remnant polarization (2Pr increasing from 23 μC/cm2 to 46 μC/cm2. The improvements observed in the electrical properties were discussed on the basis of chemical homogeneity and uniform ionic distribution.

  13. Effect of powder processing conditions on the electromechanical properties of lithium doped potassium sodium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Mensur-Alkoy, E.; Berksoy-Yavuz, A.

    2016-07-01

    Lithium doped potassium sodium niobate ceramics with (K0.50−x/2Na0.50−x/2Lix)NbO3 composition where x=0.04 and 0.07 were fabricated by solid state calcination and pressureless sintering methods. However, two different powder processing and calcination routes were used in this study and their effect on the structural and electrical properties were investigated and discussed. The routes were namely loose calcination and compact calcination. A general trend of decreasing grain size was observed in the sintered ceramics prepared from these powders. The most drastic effect was observed on the electromechanical properties of the samples, where the maximum strain of 7% lithium modified sample under an E-field of 50kV/cm was increased from 0.09% to 0.12% by changing processing route. Furthermore, hysteretic behavior of the strain was found to decrease. This tendency was also valid for ferroelectric hysteresis property, with remnant polarization (2Pr) increasing from 23μC/cm2 to 46μC/cm2. The improvements observed in the electrical properties were discussed on the basis of chemical homogeneity and uniform ionic distribution. (Author)

  14. Optical and electro-optic properties of potassium lithium tantalate niobate single crystals

    Science.gov (United States)

    Li, Yang; Li, Jun; Zhou, Zhongxiang; Bhalla, Amar; Guo, Ruyan

    2011-10-01

    Potassium lithium tantalate niobate single crystals with the composition of K0.95Li0.05Ta1-x NbxO3 (KLTN) 0.4

  15. Low-frequency-dependent electro-optic properties of potassium lithium tantalate niobate single crystals

    Science.gov (United States)

    Li, Yang; Li, Jun; Zhou, Zhongxiang; Guo, Ruyan; Bhalla, Amar S.

    2013-05-01

    A series of lead-free ferroelectric potassium lithium tantalate niobate K0.95Li0.05Ta1-xNbxO3 (x = 0.78, 0.69, 0.60, 0.52) single crystals were grown using the top-seeded melt growth method. The low-frequency-dependent linear electro-optic properties of K0.95Li0.05Ta1-xNbxO3 single crystals in the tetragonal state were investigated using the Senarmont method, autoscanning Mach-Zehnder interferometer technique and AC measurement method at room temperature. The electro-optic measurements were taken with continuous low frequency (from 1 kHz to 100 kHz) of a sinusoidal electric field, and large electro-optic responses were observed. For every component, the values of the electro-optic coefficients γ33, γ13 and γc decrease with the increase of frequency. However, the γ51 shows low sensitivity to the change of frequency. γ33, γ13 and γc increase with tantalum content, but γ51 decreases with the increase of tantalum content. The electro-optic properties of high-optical-quality K0.95Li0.05Ta1-xNbxO3 single crystals forecast their outstanding potential in various electro-optic applications.

  16. PHYSICAL AND ELECTRICAL PROPERTIES ENHANCEMENT OF RARE-EARTH DOPED-POTASSIUM SODIUM NIOBATE (KNN: A REVIEW

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    Akmal Mat Harttat Maziati

    2015-06-01

    Full Text Available Alkaline niobate mainly potassium sodium niobate, (KxNa1-x NbO3 (abreviated as KNN has long attracted attention as piezoelectric materials as its high Curie temperature (Tc and piezoelectric properties. The volatility of alkaline element (K, Na is, however detrimental to the stoichiometry of KNN, contributing to the failure to achieve high-density structure and lead to the formation of intrinsic defects. By partially doping of several rare-earth elements, the inherent defects could be improved significantly. Therefore, considerable attempts have been made to develop doped-KNN based ceramic materials with high electrical properties. In this paper, these research activities are reviewed, including dopants type and doping role in KNN perovskite structure.

  17. The development of potassium tantalate niobate thin films for satellite-based pyroelectric detectors

    Energy Technology Data Exchange (ETDEWEB)

    Cherry, Hilary B.B. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

    1997-05-01

    Potassium tantalate niobate (KTN) pyroelectric detectors are expected to provide detectivities, of 3.7 x 1011 cmHz 1/2W-1 for satellite-based infrared detection at 90 K. The background limited detectivity for a room-temperature thermal detector is 1.8 x 1010 cmHz1/2W-1 . KTN is a unique ferroelectric for this application because of the ability to tailor the temperature of its pyroelectric response by adjusting its ratio of tantalum to niobium. The ability to fabricate high quality KTN thin films on Si-based substrates is crucial to the development of KTN pyroelectric detectors. SixNymembranes created on the Si substrate will provide the weak thermal link necessary to reach background limited detectivities. The device dimensions obtainable by thin film processing are expected to increase the ferroelectric response by 20 times over bulk fabricated KTN detectors. In addition, microfabrication techniques allow for easier array development. This is the first reported attempt at growth of KTN films on Si-based substrates. Pure phase perovskite films were grown by pulsed laser deposition on SrRuO3/Pt/Ti/SixNy/Si and SrRuO3/SixNy/Si structures; room temperature dielectric permittivities for the KTN films were 290 and 2.5, respectively. The dielectric permittivity for bulk grown, single crystal KTN is ~380. In addition to depressed dielectric permittivities, no ferroelectric hysteresis was found between 80 and 300 K for either structure. RBS, AES, TEM and multi-frequency dielectric measurements were used to investigate the origin of this apparent lack of ferroelectricity. Other issues addressed by this dissertation include: the role of oxygen and target density during pulsed laser deposition of KTN thin films; the use of YBCO, LSC and Pt as direct contact bottom electrodes to the KTN films, and the adhesion of the bottom

  18. Electrical properties of lead-free Fe-doped niobium-rich potassium lithium tantalate niobate single crystals

    Science.gov (United States)

    Li, Yang; Li, Jun; Zhou, Zhongxiang; Guo, Ruyan; Bhalla, Amar S.

    2013-12-01

    Lead-free, 0.025 wt% Fe-doped niobium-rich potassium lithium tantalate niobate Fe: K0.95Li0.05Ta1-xNbxO3 single crystals have been grown by the top-seeded melt growth method. All the transition temperatures have been determined by the dielectric constant and loss-dependent temperature. The spontaneous polarizations computed by the integration of pyroelectric coefficients over all the temperatures are consistent with the results of the P-E hysteresis loops. The piezoelectric constants and electromechanical coupling factors are attractive among lead-free piezoelectric materials. With suitable Fe-doping, the electrical properties of KLTN single crystals have been improved overall and can be compared to those of the current important lead-based piezoelectric materials.

  19. Consistent Atomic Geometries and Electronic Structure of Five Phases of Potassium Niobate from Density-Functional Theory

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    Falko Schmidt

    2017-01-01

    Full Text Available We perform a comprehensive theoretical study of the structural and electronic properties of potassium niobate (KNbO3 in the cubic, tetragonal, orthorhombic, monoclinic, and rhombohedral phase, based on density-functional theory. The influence of different parametrizations of the exchange-correlation functional on the investigated properties is analyzed in detail, and the results are compared to available experimental data. We argue that the PBEsol and AM05 generalized gradient approximations as well as the RTPSS meta-generalized gradient approximation yield consistently accurate structural data for both the external and internal degrees of freedom and are overall superior to the local-density approximation or other conventional generalized gradient approximations for the structural characterization of KNbO3. Band-structure calculations using a HSE-type hybrid functional further indicate significant near degeneracies of band-edge states in all phases which are expected to be relevant for the optical response of the material.

  20. Construction of waveguiding structures in potassium lithium tantalate niobate crystals by combined laser ablation and ion implantation

    Science.gov (United States)

    Yashar, Ayelet Badichi; Ilan, Harel; Agranat, Aharon J.

    2015-02-01

    A generic methodology for constructing complex integrated electro-optic circuits in waveguided configurations is presented. The method is based on combining two techniques, "laser ablation" and "refractive index engineering by ion implantations." The constructed circuits are side-cladded by air trenches that were produced using laser ablation and bottom-cladded by a layer with a reduced refractive index which is generated through the implantation of He+ ions. This fabrication technique enables the construction of circular structures with complex geometry featuring small radii of curvature, and further can be employed to construct microfluidic channels on the same substrate. The research demonstrates waveguides in both linear and circular configurations that were constructed in a potassium lithium tantalate niobate (KLTN) substrate using the aforementioned method, proving that this substrate is a suitable candidate for use in creating laboratories-on-a-chip with multifunctional capabilities. The proposed techniques used in the research are generic and applicable to a wide range of substrates.

  1. Photoresponsive multilayer spiral nanotubes: intercalation of polyfluorinated cationic azobenzene surfactant into potassium niobate.

    Science.gov (United States)

    Tong, Zhiwei; Takagi, Shinsuke; Shimada, Tetsuya; Tachibana, Hiroshi; Inoue, Haruo

    2006-01-25

    The first successful synthesis of photoresponsive multilayer spiral nanotubes by the introduction of polyfluorinate cationic azobenzene derivative, trans-[2-(2,2,3,3,4,4,4-heptafluorobutylamino)ethyl]-{2-[4-(4-hexyphenylazo)-phenoxy]ethyl}dimethylammonium (abbreviated as C3F7-Azo+), into layered niobate interlayer I by a two-step guest-guest exchange method using the intercalation compound, methyl viologen (MV2+)-K4Nb6O17, as precursor is reported.

  2. New functionalities of potassium tantalate niobate deflectors enabled by the coexistence of pre-injected space charge and composition gradient

    Science.gov (United States)

    Zhu, Wenbin; Chao, Ju-Hung; Chen, Chang-Jiang; Campbell, Adrian L.; Henry, Michael G.; Yin, Stuart Shizhuo; Hoffman, Robert C.

    2017-10-01

    In most beam steering applications such as 3D printing and in vivo imaging, one of the essential challenges has been high-resolution high-speed multi-dimensional optical beam scanning. Although the pre-injected space charge controlled potassium tantalate niobate (KTN) deflectors can achieve speeds in the nanosecond regime, they deflect in only one dimension. In order to develop a high-resolution high-speed multi-dimensional KTN deflector, we studied the deflection behavior of KTN deflectors in the case of coexisting pre-injected space charge and composition gradient. We find that such coexistence can enable new functionalities of KTN crystal based electro-optic deflectors. When the direction of the composition gradient is parallel to the direction of the external electric field, the zero-deflection position can be shifted, which can reduce the internal electric field induced beam distortion, and thus enhance the resolution. When the direction of the composition gradient is perpendicular to the direction of the external electric field, two-dimensional beam scanning can be achieved by harnessing only one single piece of KTN crystal, which can result in a compact, high-speed two-dimensional deflector. Both theoretical analyses and experiments are conducted, which are consistent with each other. These new functionalities can expedite the usage of KTN deflection in many applications such as high-speed 3D printing, high-speed, high-resolution imaging, and free space broadband optical communication.

  3. Structure and magnetic properties of chromium doped cobalt molybdenum nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Guskos, Niko; Żołnierkiewicz, Grzegorz; Typek, Janusz; Guskos, Aleksander [Institute of Physics, Faculty of Mechanical Engineering and Mechatronics, West Pomeranian University of Technology, Szczecin, Piastów 48, 70-311 Szczecin (Poland); Adamski, Paweł; Moszyński, Dariusz [Institute of Inorganic Chemical Technology and Environment Engineering, West Pomeranian University of Technology, Szczecin, Pułaskiego 10, 70-322 Szczecin (Poland)

    2016-09-15

    Four nanocomposites containing mixed phases of Co{sub 3}Mo{sub 3}N and Co{sub 2}Mo{sub 3}N doped with chromium have been prepared. A linear fit is found for relation between Co{sub 2}Mo{sub 3}N and chromium concentrations. The magnetization in ZFC and FC modes at different temperatures (2–300 K) and in applied magnetic fields (up to 70 kOe) have been investigated. It has been detected that many magnetic characteristics of the studied four nanocomposites correlate not with the chromium concentration but with nanocrystallite sizes. The obtained results were interpreted in terms of magnetic core-shell model of a nanoparticle involving paramagnetic core with two magnetic sublattices and a ferromagnetic shell related to chromium doping. - Highlights: • A new chromium doped mixed Co-Mn-N nanocomposites were synthesized. • Surface ferromagnetism was detected in a wide temperature range. • Core-shell model was applied to explain nanocomposites magnetism.

  4. Piezoelectric and ferroelectric properties of lead-free niobium-rich potassium lithium tantalate niobate single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jun, E-mail: lijuna@hit.edu.cn [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Li, Yang [Department of chemistry, Harbin Institute of Technology, Harbin 150001 (China); Zhou, Zhongxiang [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Guo, Ruyan; Bhalla, Amar S. [Multifunctional Electronic Materials and Device Research Lab, Department of Electrical and Computer Engineering, The University of Texas at San Antonio, San Antonio 78249 (United States)

    2014-01-01

    Graphical abstract: - Highlights: • Lead-free K{sub 0.95}Li{sub 0.05}Ta{sub 1−x}Nb{sub x}O{sub 3} single crystals were grown using the top-seeded melt growth method. • The piezoelectric and ferroelectric properties of as-grown crystals were systematically investigated. • The piezoelectric properties are very attractive, e.g. for x = 0.60 composition, k{sub t} ≈ 70%, k{sub 31} ≈ 70%, k{sub 33} ≈ 77%, d{sub 31} ≈ 230 pC/N, d{sub 33} ≈ 600 pC/N. • The coercive fields of P–E hysteresis loops are quite small, about or less than 1 kV/mm. - Abstract: Lead-free potassium lithium tantalate niobate single crystals with the composition of K{sub 0.95}Li{sub 0.05}Ta{sub 1−x}Nb{sub x}O{sub 3} (abbreviated as KLTN, x = 0.51, 0.60, 0.69, 0.78) were grown using the top-seeded melt growth method. Their piezoelectric and ferroelectric properties in as-grown crystals have been systematically investigated. The phase transitions and Curie temperatures were determined from dielectric and pyroelectric measurements. Piezoelectric coefficients and electromechanical coupling factors in thickness mode, length-extensional mode and longitudinal mode were obtained. The piezoelectric properties are very attractive, e.g. for x = 0.60 composition, k{sub t} ≈ 70%, k{sub 31} ≈ 70%, k{sub 33} ≈ 77%, d{sub 31} ≈ 230 pC/N, d{sub 33} ≈ 600 pC/N are comparable to the lead-based PZT composition. The polarization versus electric field hysteresis loops show saturated shapes. In short, lead-free niobium-rich KLTN system possesses comparable properties to those in important lead-based piezoelectric material nowadays.

  5. Potassium Sodium Niobate-Based Lead-Free Piezoelectric Multilayer Ceramics Co-Fired with Nickel Electrodes

    Science.gov (United States)

    Kawada, Shinichiro; Hayashi, Hiroyuki; Ishii, Hideki; Kimura, Masahiko; Ando, Akira; Omiya, Suetake; Kubodera, Noriyuki

    2015-01-01

    Although lead-free piezoelectric ceramics have been extensively studied, many problems must still be overcome before they are suitable for practical use. One of the main problems is fabricating a multilayer structure, and one solution attracting growing interest is the use of lead-free multilayer piezoelectric ceramics. The paper reviews work that has been done by the authors on lead-free alkali niobate-based multilayer piezoelectric ceramics co-fired with nickel inner electrodes. Nickel inner electrodes have many advantages, such as high electromigration resistance, high interfacial strength with ceramics, and greater cost effectiveness than silver palladium inner electrodes. However, widely used lead zirconate titanate-based ceramics cannot be co-fired with nickel inner electrodes, and silver palladium inner electrodes are usually used for lead zirconate titanate-based piezoelectric ceramics. A possible alternative is lead-free ceramics co-fired with nickel inner electrodes. We have thus been developing lead-free alkali niobate-based multilayer ceramics co-fired with nickel inner electrodes. The normalized electric-field-induced thickness strain (Smax/Emax) of a representative alkali niobate-based multilayer ceramic structure with nickel inner electrodes was 360 pm/V, where Smax denotes the maximum strain and Emax denotes the maximum electric field. This value is about half that for the lead zirconate titanate-based ceramics that are widely used. However, a comparable value can be obtained by stacking more ceramic layers with smaller thicknesses. In the paper, the compositional design and process used to co-fire lead-free ceramics with nickel inner electrodes are introduced, and their piezoelectric properties and reliabilities are shown. Recent advances are introduced, and future development is discussed. PMID:28793646

  6. Photoelectrochemical water splitting on chromium-doped titanium dioxide nanotube photoanodes prepared by single-step anodizing

    Energy Technology Data Exchange (ETDEWEB)

    Momeni, Mohamad Mohsen, E-mail: mm.momeni@cc.iut.ac.ir; Ghayeb, Yousef

    2015-07-15

    Graphical abstract: Current–potential curves with chopped light measured in 1 M NaOH with a scan rate of 5 mV s{sup −1} for the different samples. - Highlights: • Cr-doped TiO{sub 2} nanotube layers (Cr–TiO{sub 2}NTs) were synthesized by anodizing of titanium in a single-step process. • Photoelectrochemical water splitting of Cr–TiO{sub 2}NTs is higher than that of pure TiO{sub 2} nanotubes (TiO{sub 2}NTs). • Quantity effect of chromium in these composite for photoelectrochemical water splitting is investigated. • Maximum hydrogen production of 37 μL/cm{sup 2} after 240 min is obtained. - Abstract: Cr-doped TiO{sub 2} nanotubes (Cr–TiO{sub 2}NTs) with different amounts of chromium were obtained directly by the electrochemical anodic oxidation of titanium foils in a single-step process using potassium chromate as the chromium source. The effects of chromium amount in anodizing solution on the morphologies, structure, photoabsorption and photoelectrochemical water splitting of the TiO{sub 2} nanotube array film were investigated. Diffuse reflectance spectra showed an increase in the visible absorption relative to undoped TiO{sub 2}NTs. The photoelectrochemical performance was examined under visible irradiation in 1 M NaOH electrolyte. Photo-electrochemical characterization shows that chromium doping efficiently enhances the photo-catalytic water splitting performance of Cr-doped TiO{sub 2} nanotube samples. The sample (Cr–TiO{sub 2}NTs-1) exhibited better photo-catalytic activity than the undoped TiO{sub 2}NTs and Cr–TiO{sub 2}NTs fabricated using other chromium concentrations. This can be attributed to the effective separation of photogenerated electron–hole upon the substitutional introduction of appropriate Cr amount in to the TiO{sub 2} nanotube structure.

  7. Potassium

    Science.gov (United States)

    ... and blackberries Root vegetables, such as carrots and potatoes Citrus fruits, such as oranges and grapefruit Your kidneys help to keep the right amount of potassium in your body. If you have chronic kidney disease, your kidneys may not remove extra potassium from ...

  8. Atomic-scale effects of chromium-doping on defect behaviour in uranium dioxide fuel

    Science.gov (United States)

    Guo, Zhexi; Ngayam-Happy, Raoul; Krack, Matthias; Pautz, Andreas

    2017-05-01

    The effects of doping conventional UO2 fuel with chromium are studied through atomistic simulations using empirical force field methods. We first analyse the stable structures of unirradiated doped fuel by determining the preferred lattice configuration of chromium ions and oxygen vacancies within the matrix. In order to understand the physical effects of the dopants, we investigate the energy change upon inserting isolated defects and Frenkel pairs in the vicinity of chromium. The behaviour of point defects is then studied with collision cascade simulations and relaxation of doped simulation cells containing Frenkel pairs. The defective structures are analysed using an in-house tool named ASTRAM. Results indicate definite effects of chromium-doping on the ease with which defects are formed. Moreover, the extent of Cr effects on the residual damage following a displacement cascade is dependent on the dopant distribution and concentration in the fuel matrix.

  9. Photocatalysis with chromium-doped TiO2: Bulk and surface doping

    KAUST Repository

    Ould-Chikh, Samy

    2014-04-15

    The photocatalytic properties of TiO2 modified by chromium are usually found to depend strongly on the preparation method. To clarify this problem, two series of chromium-doped titania with a chromium content of up to 1.56 wt % have been prepared under hydrothermal conditions: the first series (Cr:TiO2) is intended to dope the bulk of TiO2, whereas the second series (Cr/TiO2) is intended to load the surface of TiO2 with Cr. The catalytic properties have been compared in the photocatalytic oxidation of formic acid. Characterization data provides evidence that in the Cr/TiO2 catalysts chromium is located on the surface of TiO2 as amorphous CrOOH clusters. In contrast, in the Cr:TiO 2 series, chromium is mostly dissolved in the titania lattice, although a minor part is still present on the surface. Photocatalytic tests show that both series of chromium-doped titania demonstrate visible-light-driven photo-oxidation activity. Surface-doped Cr/TiO2 solids appear to be more efficient photocatalysts than the bulk-doped Cr:TiO2 counterparts. It\\'s classified! The photocatalytic properties of TiO2 modified by chromium depend strongly on the preparation method. To clarify this problem, two types of modified titania are discussed: one with CrIII doped in the bulk and one with CrOOH clusters on the TiO2 surface (see picture). Both series show visible-light-driven photo-oxidation activity. However, surface modification appears to be a more efficient strategy. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Optical properties of nanocrystalline potassium lithium niobate in the glass system (100-x) TeO2-x(1.5K2O-Li2O-2.5Nb2O5).

    Science.gov (United States)

    Ahamad, M Niyaz; Varma, K B R

    2009-08-01

    Optically clear glasses of various compositions in the system (100-x) TeO2-x(1.5K2O-Li2O-2.5Nb2O5) (2 melt-quenching technique. The glassy nature of the as-quenched samples was established via differential scanning calorimetry (DSC). The amorphous and the crystalline nature of the as-quenched and heat-treated samples were confirmed by the X-ray powder diffraction and transmission electron microscopic (TEM) studies. Transparent glasses comprising potassium lithium niobate (K3Li2Nb5O15) microcrystallites on the surface and nanocrystallites within the glass were obtained by controlled heat-treatment of the as-quenched glasses just above the glass transition temperature (T(g)). The optical transmission spectra of these glasses and glass-crystal composites of various compositions were recorded in the 200-2500 nm wavelength range. Various optical parameters such as optical band gap, Urbach energy, refractive index were determined. Second order optical non-linearity was established in the heat-treated samples by employing the Maker-Fringe method.

  11. Nanocasting synthesis of chromium doped mesoporous CeO2 with enhanced visible-light photocatalytic CO2 reduction performance.

    Science.gov (United States)

    Wang, Yangang; Bai, Xia; Wang, Fei; Kang, Shifei; Yin, Chaochuang; Li, Xi

    2017-10-05

    Chromium doped mesoporous CeO2 catalysts were synthesized via a simple nanocasting route by using silica SBA-15 as the template and metal nitrates as precursors. The effect of Cr doping concentration (5%, 10%, 15% and 20% of the initial Cr/(Cr+Ce) molar percentage) on the structures of these catalysts and their photocatalytic performances in reduction of CO2 with H2O were investigated. The results indicated that the introduction of Cr species could effectively extend the spectral response range from UV to visible light region (400-700nm) and improve the electronic conductivity for the mesoporous CeO2 catalysts which exhibited an enhanced photocatalytic activity in the reduction of CO2 with H2O when compared with the non-doped counterpart. The highest CO and CH4 yield of 16.2μmol/g-cat. and 10.1μmol/g-cat., respectively, were acquired on the optimal chromium doped CeO2 catalyst with the initial Cr(Cr+Ce) molar percentage of 15% under 8h visible-light irradiation, which were more than twice as high as that of bare CeO2. The remarkably increased photocatalytic performance should be attributed to the advantageous structural and compositional features of the chromium doped mesoporous CeO2. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Generation of sub-100-fs pulses from a CW mode-locked chromium-doped forsterite laser

    Science.gov (United States)

    Seas, A.; Petricevic, V.; Alfano, R. R.

    1992-01-01

    Generation of femtosecond pulses from a continuous-wave mode-locked chromium-doped forsterite laser is reported. The forsterite laser was actively mode locked by using an acoustooptic modulator operating at 78 MHz with two Brewster high-dispersion glass prisms for intracavity chirp compensation. Transform-limited sub-100-fs pulses were routinely generated in the TEM(00) mode with 85 mW of continuous power (with 1 percent output coupler), tunable over 1230-1280 nm. The shortest pulses measured had a 60-fs pulse width.

  13. Análise cristalográfica da solução sólida com estrutura tipo Tungstênio Bronze de niobato de potássio e estrôncio dopado com ferro Crystallographic analysis of the solid solution of iron doped potassium strontium niobate with tetragonal tungsten bronze structure

    Directory of Open Access Journals (Sweden)

    Silvania Lanfredi

    2010-01-01

    Full Text Available Solid solution of iron doped potassium strontium niobate with KSr2(FeNb4O15-Δ stoichiometry was prepared by high efficiency ball milling method. Structural characterization was carried out by X-ray diffraction. Crystalline structure was analyzed by the Rietveld refinements using the FullProf software. The results showed a tetragonal system with the tetragonal tungsten bronze structure - TTB (a = 12.4631 (2 Å and c = 3.9322 (6 Å, V = 610.78 (2 ų. In this work, the sites occupancy by the K+, Sr2+ and Fe3+ cations on the TTB structure were determined. NbO6 polihedra distortion and its correlation with the theoretical polarization are discussed.

  14. Fabrication and characterization of chromium-doped nanophase separated yttria-alumina-silica glass-based optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Debjit; Dhar, Anirban; Das, Shyamal; Paul, Mukul C. [Fiber Optics and Photonics Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata (India); Kir' yanov, Alexander V. [Centro de Investigaciones en Optica, Guanajuato (Mexico); Bysakh, Sandip [Electron Microscopic Section, Material Characterization Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata (India)

    2015-08-15

    The basic material and optical properties of chromium-doped nanophase-separated yttria-alumina-silica (YAS) glass based optical preforms and fibers, fabricated through the modified chemical vapor deposition process in conjunction with solution doping technique under suitable thermal annealing conditions are reported. The size of the phase-separated particles within the core of the annealed preform is around 20-30 nm which is significantly reduced to around 5.0 nm in the drawn fiber. The absorption spectra of fibers drawn from the annealed and non-annealed preform samples revealed the presence of Cr{sup 4+}, Cr{sup 3+}, and Cr{sup 6+} specie. Numerically, extinction of absorption drops ∝3-3.5 times for the annealed sample as a result of nano-phase restructuration during annealing process. Intense broadband emission (within 500-800 nm) in case of the annealed preform sample is observed as compared to the non-annealed one and is associated with the presence of Cr{sup 3+} ions in nanostructured environment inside the YAS core glass. The final fibers show broadband emission ranging from 900 to 1400 nm under pumping at 1064 nm which is attributed mainly to the presence of Cr{sup 3+}/Cr{sup 4+} ions. The fabricated fibers seem to be a potential candidate for the development of fiber laser sources for the visible and near-infra ranges and for effective Q-switching units for ∝1-1.1 μm all-fiber ytterbium lasers. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Effect of Surfactants on Morphology of Niobate Hydrate Particles in Hydrothermal Synthesis

    Science.gov (United States)

    Bai, Shan; Zhang, Fan; Karaki, Tomoaki; Adachi, Masatoshi

    2011-09-01

    The effect of surfactants on the morphology of niobate hydrate particles including potassium niobate hydrate (KN-hydrate), sodium niobate hydrate (NN-hydrate), and potassium sodium niobate hydrate (KNN-hydrate) in the hydrothermal synthesis process have been investigated. X-ray study revealed that the main constituents of these particles were K8Nb6O19·10H2O, Na8Nb6O19·13H2O, and K4Na4Nb6O19·9H2O, respectively. The morphology of the KN- and KNN-hydrate particles showed a plate-like shape with aspect ratios (diameter/thickness) of 9.2-13 and 4.5-10, respectively, which were strongly affected by sodium dodecyl benzene sulfonate (SDBS) surfactant. However, NN-hydrate showed a strip-like morphology and was not affected by SDBS quantity. Therefore, the surfactant type and its quantity play an important role in controlling the morphology of the niobate hydrate particles.

  16. The chromium doping of Ni{sub 3}Fe alloy and restructuring of grain boundary ensemble at the phase transition A1→L1{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Perevalova, Olga [Institute of Strength Physics and Material Science, Siberian Division of the Russian Academy of Sciences, Akademicheskii Av., 2/4, Tomsk, 634021 (Russian Federation); Konovalova, Elena, E-mail: knv123@yandex.ru [Surgut State University, Lenina Av., 1, Surgut, 628400 (Russian Federation); Koneva, Nina; Kozlov, Eduard [Tomsk State University of Architecture and Building, Solyanaya Sq., 2, Tomsk, 634003 (Russian Federation)

    2016-01-15

    The grain boundary structure of the Ni{sub 3}(Fe,Cr) alloy is studied in states with a short and long-range order formed at the phase transition A1→L1{sub 2}. It is found that the new boundaries of general and special types are formed during an ordering annealing, wherein the special boundaries share increases. The spectrum of special boundaries is changed due to decreasing of ∑3 boundary share. It leads to weakening of the texture in the alloy with atomic long-range order. The features of change of the special boundaries spectrum at the phase transition A1→L1{sub 2} in the Ni{sub 3}(Fe,Cr) alloy are determined by decreasing of the stacking fault energy and the atomic mean square displacement at the chromium doping.

  17. Systematic hardness studies on lithium niobate crystals

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 23; Issue 2. Systematic hardness studies on lithium niobate crystals ... In view of discrepancies in the available information on the hardness of lithium niobate, a systematic study of the hardness has been carried out. Measurements have been made on two pure lithium ...

  18. Alloying in an Intercalation Host: Metal Titanium Niobates as Anodes for Rechargeable Alkali-Ion Batteries.

    Science.gov (United States)

    Bhattacharyya, Aninda Jiban; Das, Suman; Swain, Diptikanta; Guru Row, Tayur N; Ahuja, Rajeev; Araujo, Rafael B; Shi, Songxin

    2017-12-27

    We discuss here a unique flexible non-carbonaceous layered host viz. metal titanium niobates, M-Ti-niobate (Ti: Titanium; M: Al3+, Pb2+, Sb3+, Ba2+, Mg2+) which can synergistically store both lithium-ions and sodium-ions via simultaneous intercalation and alloying mechanisms. M-Ti-niobate is formed by ion-exchange of the K+-ions, which are specifically located inside galleries between the layers formed by edge and corner sharing TiO6 and NbO6 octahedral units in the sol-gel synthesized potassium titanium niobate (KTiNbO5). Drastic volume changes (approximately 300-400%) typically associated with alloying mechanism of storage are completely tackled chemically by the unique chemical composition and structure of the M-Ti-niobates. The free space between the adjustable Ti/Nb octahedral layers easily accommodates the volume changes. Due to the presence of an optimum amount of multivalent alloying metal ions (50-75% of total K+) in the M-Ti-niobate, efficient alloying reaction takes place directly with ions and completely eliminates any form of mechanical degradation of the electroactive particles. The M-Ti-niobate can be cycled over a wide voltage range (as low as 0.01 V) and displays remarkably stable Li+ and Na+ ion cyclability (> 2 Li+/Na+ per formula unit) for widely varying current densities over few hundreds to thousands of successive cycles. The simultaneous intercalation and alloying storage mechanisms is also studied within the density functional theory (DFT) framework. DFT expectedly shows a very small variation in the volume of Al-titanium niobate following lithium alloying. Moreover, the theoretical investigations also conclusively endorse the occurrence of the alloying process of Li-ions with the Al-ions along with the intercalation process during discharge. The M-Ti-niobates studied here demonstrates a paradigm shift in chemical design of electrodes and will pave the way for development of multitude of improved electrodes for different battery chemistries

  19. Optofluidic applications with lithium niobate nanowires

    Science.gov (United States)

    Grange, Rachel; Choi, Jae-Woo; Hsieh, Chia-Lung; Pu, Ye; Psaltis, Demetri

    2010-08-01

    We report the hydrothermal synthesis of free-standing lithium niobate nanowires. We show that the versatile properties of bulk lithium niobate such as nonlinear optical effects can be exploited at the nanoscale. We describe the fabrication of polydimethylsiloxane (PDMS) microfluidics as well as indium tin oxide (ITO) electrodes with different design for dedicated applications. The control of microfluidic channel dimensions and the corresponding particle concentration is explored. Finally, the selection of fluidic conductivity for optimal dielectrophoretic trapping conditions is discussed.

  20. Optofluidic applications with lithium niobate nanowires

    OpenAIRE

    GRANGE, Rachel; Choi, Jae-Woo; Hsieh, Chia-Lung; Pu, Ye; Psaltis, Demetri

    2010-01-01

    We report the hydrothermal synthesis of free-standing lithium niobate nanowires. We show that the versatile properties of bulk lithium niobate such as nonlinear optical effects can be exploited at the nanoscale. We describe the fabrication of polydimethylsiloxane (PDMS) microfluidics as well as indium tin oxide (ITO) electrodes with different design for dedicated applications. The control of microfluidic channel dimensions and the corresponding particle concentration is explored. Finally, the...

  1. Stable liquid crystalline phases of colloidally dispersed exfoliated layered niobates.

    Science.gov (United States)

    Nakato, Teruyuki; Miyamoto, Nobuyoshi; Harada, Akiko

    2004-01-07

    Colloidally dispersed niobium oxide nanosheets obtained by exfoliation of layered niobates HNb(3)O(8) and HTiNbO(5) formed stable liquid crystalline phases; their liquid crystallinity was dependent on the niobate species exfoliated.

  2. Reduced Dimensionality Lithium Niobate Microsystems

    Energy Technology Data Exchange (ETDEWEB)

    Eichenfield, Matt [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-01-01

    The following report describes work performed under the LDRD program at Sandia National Laboratories October 2014 and September 2016. The work presented demonstrates the ability of Sandia Labs to develop state-of-the-art photonic devices based on thin film lithium niobate (LiNbO3 ). Section 1 provides an introduction to integrated LiNbO3 devices and motivation for developing thin film nonlinear optical systems. Section 2 describes the design, fabrication, and photonic performance of thin film optical microdisks fabricated from bulk LiNbO3 using a bulk implantation method developed at Sandia. Sections 3 and 4 describe the development of similar thin film LiNbO3 structures fabricated from LiNbO3 on insulator (LNOI) substrates and our demonstration of optical frequency conversion with state-of-the-art efficiency. Finally, Section 5 describes similar microdisk resonators fabricated from LNOI wafers with a buried metal layer, in which we demonstrate electro-optic modulation.

  3. Effects of erbium-and chromium-doped yttrium scandium gallium garnet and diode lasers on the surfaces of restorative dental materials: a scanning electron microscope study.

    Science.gov (United States)

    Hatipoglu, M; Barutcigil, C

    2015-01-01

    The aim of this study is to evaluate the potential effects of laser irradiation, which is commonly performed in periodontal surgery, on the surfaces of restorative materials. Five different restorative dental materials were used in this study, as follows: (1) Resin composite, (2) poly acid-modified resin composite (compomer), (3) conventional glass ionomer cement (GIC), (4) resin-modified glass ionomer cement (RMGIC), and (5) amalgam. Four cylindrical samples (8 mm diameter, 2 mm height) were prepared for each restorative material. In addition, four freshly extracted, sound human incisors teeth were selected. Two different laser systems commonly used in periodontal surgery were examined in this study: A 810 nm diode laser at a setting of 1 W with continuous-phase laser irradiation for 10 s, and an erbium-and chromium-doped yttrium scandium gallium garnet (Er, Cr: YSGG) laser at settings of 2.5 W, 3.25 W, and 4 W with 25 Hz laser irradiation for 10 s. Scanning electron microscopy (SEM) analysis was performed to evaluate the morphology and surface deformation of the restorative materials and tooth surfaces. According to the SEM images, the Er, Cr: YSGG laser causes irradiation markings that appear as demineralized surfaces on tooth samples. The Er, Cr: YSGG laser also caused deep defects on composite, compomer, and RMGIC surfaces because of its high power, and the ablation was deeper for these samples. High-magnification SEM images of GIC samples showed the melting and combustion effects of the Er, Cr: YSGG laser, which increased as the laser power was increased. In amalgam samples, neither laser left significant harmful effects at the lowest power setting. The diode laser did cause irradiation markings, but they were insignificant compared with those left by the Er, Cr: YSGG laser on the surfaces of the different materials and teeth. Within the limitations of this study, it can be concluded that Er, Cr: YSGG laser irradiation could cause distortions of the surfaces

  4. Chemically prepared lead magnesium niobate dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Tuttle, B.A.; Voigt, J.A.; Sipola, D.L.; Olson, W.R.; Goy, D.M.

    1998-11-01

    A chemical solution powder synthesis technique has been developed that produces first, uniform powders of lead magnesium niobate (PMN) with 60 to 80 nm crystallite size. The synthesis technique was based on the dissolution of lead acetate and alkoxide precursors in acetic acid followed by precipitation with oxalic acid/propanol solutions. Lead magnesium niobate ceramics fabricated from these chemically derived powders had smaller, more uniform grain size and higher dielectric constants than ceramics fabricated from mixed oxide powders that were processed under similar thermal conditions. Chem-prep PMN dielectrics with peak dielectric constants greater than 22,000 and polarizations in excess of 29 {micro}C/cm{sup 2} were obtained for 1,100 C firing treatments. Substantial decreases in dielectric constant and polarization were measured for chemically prepared PMN ceramics fired at lower temperatures, consistent with previous work on mixed oxide materials.

  5. Optical cleaning of lithium niobate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Koesters, Michael

    2010-01-15

    An all-optical method for the removal of photoexcitable electrons from photorefractive centers to get rid of optical damage in lithium niobate crystals is presented, the so-called ''optical cleaning''. The method combines the photovoltaic drift of electrons with ionic charge compensation at sufficiently high temperatures of about 180 C. Optimum choice of the light pattern plus heat dramatically decreases the concentration of photoexcitable electrons in the exposed region leading to a suppression of optical damage. Experiments with slightly iron-doped lithium niobate crystals have shown an increase of the threshold for optical damage of more than 1000 compared to those of untreated crystals. (orig.)

  6. Photo-induced morphological winding and unwinding motion of nanoscrolls composed of niobate nanosheets with a polyfluoroalkyl azobenzene derivative

    Science.gov (United States)

    Nabetani, Yu; Takamura, Hazuki; Uchikoshi, Akino; Hassan, Syed Zahid; Shimada, Tetsuya; Takagi, Shinsuke; Tachibana, Hiroshi; Masui, Dai; Tong, Zhiwei; Inoue, Haruo

    2016-06-01

    Photo-responsive nanoscrolls can be successfully fabricated by mixing a polyfluoroalkyl azobenzene derivative and a niobate nanosheet, which is exfoliated from potassium hexaniobate. In this study, we have found that the photo-responsive nanoscroll shows a morphological motion of winding and unwinding, which is basically due to the nanosheet sliding within the nanoscroll, by efficient photo-isomerization reactions of the intercalated azobenzene in addition to the interlayer distance change of the nanoscrolls. The relative nanosheet sliding of the nanoscroll is estimated to be ca. 280 nm from the AFM morphology analysis. The distance of the sliding motion is over 20 times that of the averaged nanosheet sliding in the azobenzene/niobate hybrid film reported previously. Photo-responsive nanoscrolls can be expected to be novel photo-activated actuators and artificial muscle model materials.Photo-responsive nanoscrolls can be successfully fabricated by mixing a polyfluoroalkyl azobenzene derivative and a niobate nanosheet, which is exfoliated from potassium hexaniobate. In this study, we have found that the photo-responsive nanoscroll shows a morphological motion of winding and unwinding, which is basically due to the nanosheet sliding within the nanoscroll, by efficient photo-isomerization reactions of the intercalated azobenzene in addition to the interlayer distance change of the nanoscrolls. The relative nanosheet sliding of the nanoscroll is estimated to be ca. 280 nm from the AFM morphology analysis. The distance of the sliding motion is over 20 times that of the averaged nanosheet sliding in the azobenzene/niobate hybrid film reported previously. Photo-responsive nanoscrolls can be expected to be novel photo-activated actuators and artificial muscle model materials. Electronic supplementary information (ESI) available: Fig. S1. Photo-isomerization reaction of nanoscrolls. See DOI: 10.1039/c6nr02177h

  7. Fabrication of periodically poled lithium niobate chips for optical ...

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... An electric-field poling process was established that yielded uniform periodically poled lithium niobate (PPLN) in 0.5 mm thick lithium niobate substrate. We have fabricated 50 mm long fanned as well as multigrating PPLNs having period variations from 25 m to 32 m. These PPLNs are required for ...

  8. Optical properties of lithium niobate single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Palatnikov, M.N.; Sidorov, N.V.; Biryukova, I.V.; Kalinnikov, V.T. [Institute of Chemistry, Kola Science Centre RAS, 26a Fersman str., 184200 Apatity, Murmansk region (Russian Federation); Bormanis, K. [Institute of Solid State Physics, University of Latvia, 8 Kengaraga str., Riga, LV-1063 (Latvia)

    2005-01-01

    Studies of thermal and {gamma}-irradiation effects on the optical properties in congruous lithium niobate single crystals containing Y, Mg, Gd, B, and Zn dopants including samples with double dopants Y, Mg and Gd, Mg are reported. Formation of defects at irradiation and thermal treatment of the samples is explored by electron absorption spectra. Considerable increase of absorption with the dose of {gamma}-radiation is observed at 500 nm. The changes of absorption examined under different conditions are explained by creation and destruction of Nb{sup 4+} defects. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Potassium test

    Science.gov (United States)

    ... also be done if your provider suspects metabolic acidosis (for example, caused by uncontrolled diabetes) or alkalosis ( ... Hypoaldosteronism (very rare) Kidney failure Metabolic or respiratory acidosis Red blood cell destruction Too much potassium in ...

  10. Terahertz generation from Cu ion implantation into lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuhua, E-mail: wyh61@163.com [Hubei Province Key Laboratory of Systems Science in Metallurgical Process, Wuhan university of Science and Technology, Wuhan 430081 (China); Wang, Ruwu; Yuan, Jie [Hubei Province Key Laboratory of Systems Science in Metallurgical Process, Wuhan university of Science and Technology, Wuhan 430081 (China); Wang, Yumei [Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China)

    2014-03-15

    In this letter, the authors present first observation of terahertz generation from Cu implantation of lithium niobate crystal substrate. Lithium niobate single crystal is grown by Czochralski method. Metal nanoparticles synthesized by Cu ion implantation were implanted into lithium niobate single crystal using metal vapor vacuum arc (MEVVA) ion source. 1 kHz, 35 fs laser pulse centred at 800 nm was focused onto the samples. The supercontinuum spectra of the sample are obtained. Terahertz was generated via this kind of sample and investigated using the electro-optical sampling technique. The findings suggest that under the investigated implantation parameter, a strong spectral component in excess of 0.46 THz emission was found from Cu ion implantation of lithium niobate. -- Highlights: • We first observation of terahertz generation from Cu implantation of lithium niobate crystal substrate. • Lithium niobate single crystal is grown by Czochralski method. Cu nanoparticles in lithium niobate have been formed by using MEVVA ion source. • The THz bandwidth and center from this kind of sample were determined.

  11. Electrochemical reactions of layered niobate material as novel anode for sodium ion batteries

    Science.gov (United States)

    Nakayama, Hideki; Nose, Masafumi; Nakanishi, Shinji; Iba, Hideki

    2015-08-01

    The electrochemical performances of layered niobium oxide materials were investigated for the first time as novel anode active materials for the sodium-ion battery. The layered niobate with the formula KNb3O8 was synthesized by a solid-state reaction and has been evaluated as an anode electrode by a cyclic voltammetry technique and galvanostatic charge/discharge tests. The crystal structure of KNb3O8 contains the NbO6 octahedral units and potassium alkali-metal ions interlayer to form the layered structure. KNb3O8 has a redox reaction around 1 V vs. Na/Na+ and has a reversible capacity of 104 mAh/g corresponding to the 1.7 Na+ insertion/extraction in the KNb3O8 structure. The Nb K-edge X-ray absorption near edge structure (XANES) shows that the Nb oxidation state is converted from Nb5+ to Nb4+ during the Na+ insertion stage, and reversibly recovered to Nb5+ during the Na+ extraction stage. This is the first report that the layered niobate of KNb3O8 reversibly reacts with Na+ at the potential around 1 V vs. Na/Na+ via the Nb5+/4+ redox reaction.

  12. Grating coupler on single-crystal lithium niobate thin film

    Science.gov (United States)

    Chen, Zhihua; Wang, Yiwen; Jiang, Yunpeng; Kong, Ruirui; Hu, Hui

    2017-10-01

    The grating coupler on single-crystal lithium niobate thin film (lithium niobate on insulator, LNOI) was designed. A bottom reflector was added in the LNOI material to improve the coupling efficiency. The grating structure was optimized by FDTD method. The material parameters such as layer thickness of lithium niobate thin film, SiO2 thickness were discussed with respect to the coupling efficiency, and the tolerances of grating period, etch depth, groove width and fiber position were also studied systematically. The simulated maximum coupling efficiency from a grating coupler with (without) bottom reflector to a single-mode fiber is about 78% (40%) in z-cut LNOI for TE polarization.

  13. Probing the pseudo-1-D ion diffusion in lithium titanium niobate anode for Li-ion battery.

    Science.gov (United States)

    Das, Suman; Dutta, Dipak; Araujo, Rafael B; Chakraborty, Sudip; Ahuja, Rajeev; Bhattacharyya, Aninda J

    2016-08-10

    Comprehensive understanding of the charge transport mechanism in the intrinsic structure of an electrode material is essential in accounting for its electrochemical performance. We present here systematic experimental and theoretical investigations of Li(+)-ion diffusion in a novel layered material, viz. lithium titanium niobate. Lithium titanium niobate (exact composition Li0.55K0.45TiNbO5·1.06H2O) is obtained from sol-gel synthesized potassium titanium niobate (KTiNbO5) by an ion-exchange method. The Li(+)-ions are inserted and de-inserted preferentially into the galleries between the octahedral layers formed by edge and corner sharing TiO6 and NbO6 octahedral units and the effective chemical diffusion coefficient, is estimated to be 3.8 × 10(-11) cm(2) s(-1) using the galvanostatic intermittent titration technique (GITT). Calculations based on density functional theory (DFT) strongly confirm the anisotropic Li(+)-ion diffusion in the interlayer galleries and that Li(+)-ions predominantly diffuse along the crystallographic b-direction. The preferential Li(+)-ion diffusion along the b-direction is assisted by line-defects, which are observed to be higher in concentration along the b-direction compared to the a- and c-directions, as revealed by high resolution electron microscopy. The Li-Ti niobate can be cycled to low voltages (≈0.2 V) and show stable and satisfactory battery performance over 100 cycles. Due to the possibility of cycling to low voltages, cyclic voltammetry and X-ray photoelectron spectroscopy convincingly reveal the reversibility of Ti(3+) ↔ Ti(2+) along with Ti(4+) ↔ Ti(3+) and Nb(5+) ↔ Nb(4+).

  14. Structures at the Atomic Level of Cobalt, Zinc and Lead Niobates (with an Appendix: Atomic structure of cobalt niobate crystal)

    OpenAIRE

    Raji Heyrovska

    2011-01-01

    The author has found in recent years that bond lengths are exact sums of the radii of adjacent atoms and or ions, where the ions have Golden ratio based radii. This work was prompted by the exciting observation last year of the Golden ratio in the magnetic properties of cobalt niobate. It is shown here that in cobalt and zinc niobates, cobalt, zinc and oxygen ions have Golden ratio based ionic radii, whereas in lead niobate, all atoms have covalent radii. Also, the angles at the single bond o...

  15. Ridge Waveguide Structures in Magnesium-Doped Lithium Niobate Project

    Data.gov (United States)

    National Aeronautics and Space Administration — AdvR, Inc. proposes the development of an efficient process for fabricating ridge waveguides in magnesium-doped lithium niobate (MgO:LN). The effort will include,...

  16. Ridge Waveguide Structures in Magnesium-Doped Lithium Niobate Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this NASA Phase I STTR effort, the feasibility of fabricating isolated ridge waveguides in 5% magnesium-doped lithium niobate (5% MgO:LN) will be established....

  17. Lithium-Niobate-Silica Hybrid Whispering-Gallery-Mode Resonators.

    Science.gov (United States)

    Bo, Fang; Wang, Jie; Cui, Jiao; Ozdemir, Sahin Kaya; Kong, Yongfa; Zhang, Guoquan; Xu, Jingjun; Yang, Lan

    2015-12-22

    Lithium-niobate-silica hybrid resonators with quality factors higher than 10(5) are fabricated by depositing a layer of polycrystalline lithium niobate on the flat top surfaces of inverted-wedge silica microdisk resonators. All-optical modulation with improved performance over silica-only resonators and electro-optic modulation not achievable in silica-only resonators are realized in the hybrid resonators. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Potassium in diet

    Science.gov (United States)

    ... diet; Hypokalemia - potassium in the diet; Chronic kidney disease - potassium in diet; Kidney failure - potassium in diet ... potassium. Vegetables including broccoli, peas, lima beans, tomatoes, potatoes (especially their skins), sweet potatoes, and winter squash ...

  19. Precise, reproducible nano-domain engineering in lithium niobate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Boes, Andreas, E-mail: s3363819@student.rmit.edu.au; Sivan, Vijay; Ren, Guanghui; Yudistira, Didit; Mitchell, Arnan [School of Electrical and Computer Engineering, RMIT University, Melbourne, Victoria 3001 (Australia); ARC Center for Ultra-High Bandwidth Devices for Optical Systems (CUDOS), RMIT University, Melbourne, Victoria 3001 (Australia); Mailis, Sakellaris [Optoelectronics Research Centre, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Soergel, Elisabeth [Institute of Physics, University of Bonn, Wegelerstr. 8, 53115 Bonn (Germany)

    2015-07-13

    We present a technique for domain engineering the surface of lithium niobate crystals with features as small as 100 nm. A film of chromium (Cr) is deposited on the lithium niobate surface and patterned using electron beam lithography and lift-off and then irradiated with a wide diameter beam of intense visible laser light. The regions patterned with chromium are domain inverted while the uncoated regions are not affected by the irradiation. With the ability to realize nanoscale surface domains, this technique could offer an avenue for fabrication of nano-photonic and phononic devices.

  20. Precise, reproducible nano-domain engineering in lithium niobate crystals

    Science.gov (United States)

    Boes, Andreas; Sivan, Vijay; Ren, Guanghui; Yudistira, Didit; Mailis, Sakellaris; Soergel, Elisabeth; Mitchell, Arnan

    2015-07-01

    We present a technique for domain engineering the surface of lithium niobate crystals with features as small as 100 nm. A film of chromium (Cr) is deposited on the lithium niobate surface and patterned using electron beam lithography and lift-off and then irradiated with a wide diameter beam of intense visible laser light. The regions patterned with chromium are domain inverted while the uncoated regions are not affected by the irradiation. With the ability to realize nanoscale surface domains, this technique could offer an avenue for fabrication of nano-photonic and phononic devices.

  1. Chip-scale cavity optomechanics in lithium niobate

    CERN Document Server

    Jiang, Wei C

    2016-01-01

    We develop a chip-scale cavity optomechanical system in single-crystal lithium niobate that exhibits high optical quality factors and a large frequency-quality product as high as $3.6\\times 10^{12}$ Hz at room temperature and atmosphere. The excellent optical and mechanical properties together with the strong optomechanical coupling allow us to efficiently excite the coherent regenerative optomechanical oscillation operating at 375.8 MHz with a threshold power of 174 ${\\rm \\mu W}$ in the air. The demonstrated lithium niobate optomechanical device enables great potential for achieving electro-optic-mechanical hybrid systems for broad applications in sensing, metrology, and quantum physics.

  2. Zr doping on lithium niobate crystals: Raman spectroscopy and chemometrics

    Science.gov (United States)

    Kokanyan, Ninel; Chapron, David; Kokanyan, Edvard; Fontana, Marc D.

    2017-03-01

    Raman measurements were investigated on Zr-doped lithium niobate LiNbO3 crystals with different concentrations. Spectra were treated by fitting procedure and principal component analysis which both provide results consistent with each other. The concentration dependence of the frequency on the main low-frequency optical phonons provides an insight of site incorporation of Zr ions in the host lattice. The threshold concentration of about 2% is evidenced, confirming the interest of Zr doping as an alternative to Mg doping for the reduction of the optical damage in lithium niobate.

  3. Potassium Blood Test

    Science.gov (United States)

    ... page: https://medlineplus.gov/labtests/potassiumbloodtest.html Potassium Blood Test To use the sharing features on this page, please enable JavaScript. What is a Potassium Blood Test? A potassium blood test measures the amount of ...

  4. Reliability of lithium niobate Annealed Proton Exchanged integrated optical circuits

    Science.gov (United States)

    Kissa, Karl M.; Eng, Hogan; Lewis, David K.; Rodino, Vincent D.; Suchoski, Paul G., Jr.; Koziarz, Nancy A.

    1995-06-01

    Several studies have been performed recently that demonstrate the reliability of lithium niobate Annealed Proton Exchanged (APE) Integrated Optical Circuits (IOCs). Studies have been performed on APE IOC die as well as pigtailed and packaged devices. The tests indicate that the reliability of APE IOCs meet or surpass the needs of most military and commercial applications.

  5. Micro- and nano-domain engineering in lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Shur, V. Ya.; Akhmatkhanov, A. R.; Baturin, I. S. [Institute of Natural Sciences, Ural Federal University, 620000 Ekaterinburg, Russia and Labfer Ltd., 620014 Ekaterinburg (Russian Federation)

    2015-12-15

    The physical basis of the domain engineering in ferroelectrics and its application to lithium niobate crystals were reviewed. The unified kinetic approach to the domain structure evolution in electric field was formulated and its validity for understanding the variety of observed domain evolution scenarios was demonstrated. The kinetics and statics of the domain structure in the crystals of lithium niobate family including congruent, stoichiometric, and MgO doped ones have been discussed. The main stages of the periodical poling process and related problems have been pointed out. The basic poling techniques applied for creation of the periodical domain structures in bulk crystals and waveguides were compared. The recent applications of the periodically poled lithium niobate for light frequency conversion using second harmonic generation and optical parametric oscillation, excitation of the surface acoustic waves, and generation of terahertz radiation have been discussed. The special attention has been paid for achievements in fabrication of high-power optical parametric oscillation and integrated optical devices with periodically poled lithium niobate. The future trends in periodical poling and development of the nanodomain engineering which will allow to create the nanoscale domain patterns necessary for utilization of the new nonlinear interactions were reviewed.

  6. Adsorptive and photocatalytic removal of phenol by layered niobates organically modified through intercalation and silylation.

    Science.gov (United States)

    Kiba, Shosuke; Haga, Jun-ichi; Hashimoto, Sachika; Nakato, Teruyuki

    2010-12-01

    Layered hexaniobate K4Nb6O17 was modified with dodecylammonium ions and octadecyltrimethoxysilane molecules, which were held in the interlayer spaces by electrostatic interactions and covalent attachment to the layers, respectively. Interlayer spacing of the niobate was expanded by incorporation of the bulky organic species. Vapor adsorption isotherms of benzene and water indicated hydrophobic interlayer microenvironments of the organically modified niobates. Both of the modified niobates fairly adsorbed phenol dissolved in water. The photocatalytic activity of hexaniobate allowed the organically modified materials to photocatalytically decompose phenol upon UV irradiation. Decomposition time courses and quantitative analysis of phenol present in the system indicated that the phenol molecules adsorbed on the niobates were preferentially degraded. XRD and IR analyses of the modified niobates indicated that the silylated niobate was more durable than the ion-exchanged sample; the former kept the structure during the photocatalytic process while the latter was partly collapsed.

  7. Fatigue properties and impedance analysis of potassium sodium niobate-strontium titanate transparent ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhiyong; Fan, Huiqing; Lei, Shenhui; Wang, Ju; Tian, Hailin [Northwestern Polytechnical University, State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Xi' an (China)

    2016-10-15

    Highly transparent ferroelectric ceramics based on 0.9K{sub 0.5}Na{sub 0.5}NbO{sub 3}-0.1SrTiO{sub 3} were prepared using a pressure-less solid-state sintering method without using hot isostatic pressing and spark plasma sintering. An independence electromechanical response of bipolar switching cycles (S{sub 33} only degraded 3.2 % up to 10{sup 7} cycles) was presented in this transparent ceramics, which indicated an extremely stable property under electric field. From impedance spectroscopy and X-ray photoelectron spectroscopy analyses, it was concluded that such optical transparency and fatigue-resistant behaviors were mainly attributed to the lower density of oxygen vacancies in the ceramics. (orig.)

  8. Effect of bismuth titanate on the properties of potassium sodium niobate-based ceramics

    Directory of Open Access Journals (Sweden)

    Henry E. Mgbemere

    2017-03-01

    The dielectric constant, dielectric loss and resistivity values of the samples increase slightly with BiT addition. Good hysteresis curves are obtained in (K0.5Na0.5NbO3-based samples only at low BiT amounts. Remnant polarization values between 9 μC/cm2 and 25 μC/cm2 are obtained for K0.48Na0.48Li0.04(Nb0.9Ta0.1O3 and K0.48Na0.48Li0.04(Nb0.86Ta0.1Sb0.04O3-based samples. With the exception of KNNLT samples where the d*33 values increase from 203 ± 7 pm/V at 0 mol% to 275 ± 6 pm/V at 0.35 mol%, the d*33 values of the samples gradually decrease with increasing BiT content. This work shows that to obtain good properties for KNN-based ceramics, only very small amounts of BiT are required.

  9. Crystal growth and characterisation of mixed niobates for non-linear optical applications

    CERN Document Server

    Jiang, Q

    1999-01-01

    Temperature tuned NCPM has been realised by using both wavelengths. The measured phase matching temperatures increase with increasing spontaneous polarisation. KLN also has large non-linear optical coefficient (d sub 3 sub 1 =2.14 d sub 3 sub 1 sup l sup i sup N sup b sup O sup 3), a reasonably high damage threshold (1.75 times that of LiNbO sub 3), wide temperature acceptance (approx 5 deg C) and angular acceptance (approx 8 deg). Potassium sodium niobate (K sub x Na sub 1 sub - sub x NbO sub 3 , KNN) crystals have been grown and they are confirmed to be ferroelectric. However, they are unstable and break up into small pieces after a short period of time. By employing ferroelectric phenomenological theory, it is revealed that the birefringence of a ferroelectric crystal consists of two parts: one relating to a ferroelectric free of any electrical displacement and the other depending on the spontaneous polarisation. The theoretical outcomes provide a brief explanation of the experimental results in modifying ...

  10. Optical waveguides in lithium niobate: Recent developments and applications

    Science.gov (United States)

    Bazzan, Marco; Sada, Cinzia

    2015-12-01

    The state of the art of optical waveguide fabrication in lithium niobate is reviewed, with particular emphasis on new technologies and recent applications. The attention is mainly devoted to recently developed fabrication methods, such as femtosecond laser writing, ion implantation, and smart cut waveguides as well as to the realization of waveguides with tailored functionalities, such as photorefractive or domain engineered structures. More exotic systems, such as reconfigurable and photorefractive soliton waveguides, are also considered. Classical techniques, such as Ti in-diffusion and proton exchange, are cited and briefly reviewed as a reference standpoint to highlight the recent developments. In all cases, the application-oriented point of view is preferred, in order to provide the reader with an up-to date panorama of the vast possibilities offered by lithium niobate to integrated photonics.

  11. Penicillin V Potassium

    Science.gov (United States)

    Penicillin V potassium is an antibiotic used to treat certain infections caused by bacteria such as pneumonia, ... Penicillin V potassium comes as a tablet and liquid to take by mouth. It is usually taken ...

  12. KV7 potassium channels

    DEFF Research Database (Denmark)

    Stott, Jennifer B; Jepps, Thomas Andrew; Greenwood, Iain A

    2014-01-01

    Potassium channels are key regulators of smooth muscle tone, with increases in activity resulting in hyperpolarisation of the cell membrane, which acts to oppose vasoconstriction. Several potassium channels exist within smooth muscle, but the KV7 family of voltage-gated potassium channels have been...

  13. Structural examination of lithium niobate ferroelectric crystals by combining scanning electron microscopy and atomic force microscopy

    Science.gov (United States)

    Efremova, P. V.; Ped'ko, B. B.; Kuznecova, Yu. V.

    2016-02-01

    The structure of lithium niobate single crystals is studied by a complex technique that combines scanning electron microscopy and atomic force microscopy. By implementing the piezoresponse force method on an atomic force microscope, the domain structure of lithium niobate crystals, which was not revealed without electron beam irradiation, is visualized

  14. Potassium Secondary Batteries.

    Science.gov (United States)

    Eftekhari, Ali; Jian, Zelang; Ji, Xiulei

    2017-02-08

    Potassium may exhibit advantages over lithium or sodium as a charge carrier in rechargeable batteries. Analogues of Prussian blue can provide millions of cyclic voltammetric cycles in aqueous electrolyte. Potassium intercalation chemistry has recently been demonstrated compatible with both graphite and nongraphitic carbons. In addition to potassium-ion batteries, potassium-O2 (or -air) and potassium-sulfur batteries are emerging. Additionally, aqueous potassium-ion batteries also exhibit high reversibility and long cycling life. Because of potentially low cost, availability of basic materials, and intriguing electrochemical behaviors, this new class of secondary batteries is attracting much attention. This mini-review summarizes the current status, opportunities, and future challenges of potassium secondary batteries.

  15. Easy and versatile functionalization of lithium niobate wafers by hydrophobic trichlorosilanes

    Energy Technology Data Exchange (ETDEWEB)

    Bennes, Jonathan; Ballandras, Sylvain [Institut FEMTO-ST, CNRS, Universite de Franche-Comte, 32 Avenue de l' Observatoire, F-24044 Besancon Cedex (France); Cherioux, Frederic [Institut FEMTO-ST, CNRS, Universite de Franche-Comte, 32 Avenue de l' Observatoire, F-24044 Besancon Cedex (France)], E-mail: frederic.cherioux@femto-st.fr

    2008-12-30

    The functionalization of lithium niobate surface has been successfully obtained by the grafting of trichloro-organosilane derivatives thanks to liquid phase silanization or micro-contact printing. This functionalization has been proved by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The data show that the stability of the self-assembled monolayer (SAM) film on the trichloro(1H,1H,2H,2H-perfluorooctyl)silane-modified lithium niobate surface is largely due to the formation of a siloxy-niobate (-Si-O-Nb-) bond via a condensation reaction between -Si-Cl and niobate hydroxide (-NbOH). The extremely hydrophobic and stable SAM on lithium niobate could have useful applications in acoustic droplet handling and more generally surface acoustic waves (SAW) device preparation for lab-on-chip devices.

  16. Hydrothermal Conversion of Layered Niobate K4Nb6O17·3H2O to Rare Microporous Niobate K6Nb10.8O30.

    Science.gov (United States)

    Ide, Yusuke; Shirae, Wataru

    2017-09-18

    We report a new facile route to synthesizing K6Nb10.8O30, a rare microporous niobate. When hydrothermally treated under alkali conditions, a layered niobate, K4Nb6O17·3H2O, was converted to K6Nb10.8O30. This product had a much smaller particle size than K6Nb10.8O30, prepared by a conventional solid-state reaction, and showed enhanced adsorption properties.

  17. Formation of coherent gold nanoclusters in lithium niobate

    Science.gov (United States)

    Kling, A.; da Silva, M. F.; Soares, J. C.; Fichtner, P. F. P.; Amaral, L.; Zawislak, F. C.

    2002-05-01

    Gold nanoclusters were formed by implantation of 1×10 16 cm -2 Au + ions with an energy of 800 keV into Y-cut LiNbO 3 and subsequent annealing at 600 and 800 °C in flowing wet oxygen atmosphere. Rutherford backscattering/channeling and electron diffraction studies in plan-view transmission electron microscopy (TEM) samples revealed a highly coherent growth of the Au nanoclusters in the lithium niobate matrix. The TEM pictures also show that the Au clusters are plate-like and exhibit in the observation plane lateral dimensions that exceed the values previously obtained from optical measurements by far.

  18. Sub-band-gap laser micromachining of lithium niobate

    DEFF Research Database (Denmark)

    Christensen, F. K.; Müllenborn, Matthias

    1995-01-01

    method is reported which enables us to do laser processing of lithium niobate using sub-band-gap photons. Using high scan speeds, moderate power densities, and sub-band-gap photon energies results in volume removal rates in excess of 106µm3/s. This enables fast micromachining of small piezoelectric......Laser processing of insulators and semiconductors is usually realized using photon energies exceeding the band-gap energy. This makes laser processing of insulators difficult since high photon energies typically require either a pulsed laser or a frequency-doubled continuous-wave laser. A new...

  19. Domain wall width of lithium niobate poled during growth

    CERN Document Server

    Brooks, R; Hole, D E; Callejo, D; Bermudez, V; Diéguez, E

    2003-01-01

    Good quality crystals of periodically poled lithium niobate can be generated directly during growth. However, the temperature gradients at the zone boundaries define the width of the regions where the polarity is reversed. Hence, the region influenced the domain transition may be a significant fraction of the overall poling period for material poled during growth. Evidence for the scale of this feature is reported both by chemical etching and by the less common method of ion beam luminescence and the 'domain wall' width approximately 1 mu m for these analyses. The influence of the reversal region may differ for alternative techniques but the relevance to device design for second harmonic generation is noted.

  20. Towards integrated superconducting detectors on lithium niobate waveguides

    Science.gov (United States)

    Höpker, Jan Philipp; Bartnick, Moritz; Meyer-Scott, Evan; Thiele, Frederik; Krapick, Stephan; Montaut, Nicola; Santandrea, Matteo; Herrmann, Harald; Lengeling, Sebastian; Ricken, Raimund; Quiring, Viktor; Meier, Torsten; Lita, Adriana; Verma, Varun; Gerrits, Thomas; Nam, Sae Woo; Silberhorn, Christine; Bartley, Tim J.

    2017-08-01

    Superconducting detectors are now well-established tools for low-light optics, and in particular quantum optics, boasting high-efficiency, fast response and low noise. Similarly, lithium niobate is an important platform for integrated optics given its high second-order nonlinearity, used for high-speed electro-optic modulation and polarization conversion, as well as frequency conversion and sources of quantum light. Combining these technologies addresses the requirements for a single platform capable of generating, manipulating and measuring quantum light in many degrees of freedom, in a compact and potentially scalable manner. We will report on progress integrating tungsten transition-edge sensors (TESs) and amorphous tungsten silicide superconducting nanowire single-photon detectors (SNSPDs) on titanium in-diffiused lithium niobate waveguides. The travelling-wave design couples the evanescent field from the waveguides into the superconducting absorber. We will report on simulations and measurements of the absorption, which we can characterize at room temperature prior to cooling down the devices. Independently, we show how the detectors respond to flood illumination, normally incident on the devices, demonstrating their functionality.

  1. Lithium niobate phononic crystal for surface acoustic waves

    Science.gov (United States)

    Benchabane, S.; Khelif, A.; Rauch, J. Y.; Robert, L.; Laude, V.

    2006-02-01

    The recent theoretical and experimental demonstrations of stop bands for surface acoustic waves have greatly enlarged the potential application field for phononic crystals. The possibility of a direct excitation of these surface waves on a piezoelectric material, and their already extensive use in ultrasonics make them an interesting basis for phononic crystal based, acoustic signal processing devices. In this paper, we report on the demonstration of the existence of an absolute band gap for surface waves in a piezoelectric phononic crystal. The Surface Acoustic Wave propagation in a square lattice, two-dimensional lithium niobate phononic crystal is both theoretically and experimentally studied. A plane wave expansion method is used to predict the band gap position and width. The crystal was then fabricated by reactive ion etching of a bulk lithium niobate substrate. Standard interdigital transducers were used to characterize the phononic structure by direct electrical generation and detection of surface waves. A full band gap around 200 MHz was experimentally demonstrated, and close agreement is found with theoretical predictions.

  2. New synthesis of nanosized niobium oxides and lithium niobate particles and their characterization by XPS analysis.

    Science.gov (United States)

    Aufray, Maëlenn; Menuel, Stéphane; Fort, Yves; Eschbach, Julien; Rouxel, Didier; Vincent, Brice

    2009-08-01

    This work presents a new synthesis of nano-sized lithium niobate particles by a low temperature three steps procedure. The complete protocol implies a LiH induced reduction of NbCl5 followed by in situ spontaneous oxidation into low valence niobium nano-oxides. These niobium oxides are exposed to air atmosphere leading to pure Nb2O5 formation. Finally, the stable Nb2O5 is converted into lithium niobate LiNbO3 nanoparticles during the controlled hydrolysis of the LiH excess. The nano-sized lithium niobate particles as well as their formation processes were characterized using X-ray photoelectron spectroscopy.

  3. The r22 electro-optic coefficients in indium-doped congruent lithium-niobate crystals

    Science.gov (United States)

    Abarkan, Mustapha; Danielyan, Anush; Sewastianow, Sasha; Aillerie, Michel; Théofanous, Nicéphore; Kostritskii, Sergey; Kokanyan, Edvard

    2017-07-01

    The high- and low- frequency electro-optic coefficients r222 of In-doped lithium niobate (LN) and the corresponding dielectric permittivity as well, have been experimentally determined and compared with the results obtained in undoped congruent LN crystals. Compared to pure congruent lithium niobate, a low acoustic contribution of the electro-optic and dielectric properties are originally found in indium (In)-doped congruent lithium niobate (LN:In) crystals in the low indium concentration range [0.12-1.7 mol%]. All reported results confirm that the LN:In is a very promising candidate for several non-linear devices as Pockels cells for laser Q-switching.

  4. Absorption and reflectivity of the lithium niobate surface masked with a graphene layer

    Science.gov (United States)

    Salas, O.; Garcés, E.; Castillo, F. L.; Magaña, L. F.

    2017-01-01

    We performed simulations of the interaction of a graphene layer with the surface of lithium niobate utilizing density functional theory and molecular dynamics at 300K and atmospheric pressure. We found that the graphene layer is physisorbed on the lithium niobate surface with an adsorption energy of -0.8205 eV/(carbon-atom). Subsequently, the energy band structure, the optical absorption and reflectivity of the new system were calculated. We found important changes in these physical properties with respect to the corresponding ones of a graphene layer and of a lithium niobate crystal.

  5. Changes in the reflectivity of a lithium niobate crystal decorated with a graphene layer

    Science.gov (United States)

    Salas, O.; Garcés, E.; Castillo, F. L.; Magaña, L. F.

    2017-01-01

    Density functional theory and molecular dynamics were used to study the interaction of a graphene layer with the surface of lithium niobate. The simulations were performed at atmospheric pressure and 300K. We found that the graphene layer is physisorbed with an adsorption energy of -0.8205 eV/C-atom. Subsequently, the optical absorption of the graphene-(lithium niobate) system was calculated and compared with that of graphene solo and lithium niobate alone, respectively. The calculations were performed using the Quantum Espresso code with the GGA approximation and Vdw-DF2 (which includes long-range correlation effects as Van der Waals interactions).

  6. Potassium maldistribution revisited

    African Journals Online (AJOL)

    Medication errors contribute significantly to human and financial costs.1-4 One of these errors involves incorrect identification of concentrated potassium chloride ampoules. After coronary artery bypass grafting, potassium concentrations lower and higher than 3.3 and 5.2 mmol per liter respectively have been associated ...

  7. Potassium food supplement

    Science.gov (United States)

    Bourland, C. T.; Huber, C. S.; Rambaut, C.; Heidelbaugh, N. D.

    1973-01-01

    Potassium gluconate is considered best supplementary source for potassium. Gluconate consistently received highest taste rating and was indistinguishable from nonsupplemented samples. No unfavorable side effects were found during use, and none are reported in literature. Gluconate is normal intermediary metabolite that is readily adsorbed and produces no evidence of gastrointestinal ulcerations.

  8. Single- and double-layered organically modified nanosheets by selective interlayer grafting and exfoliation of layered potassium hexaniobate.

    Science.gov (United States)

    Kimura, Nanako; Kato, Yumi; Suzuki, Ryoko; Shimada, Akira; Tahara, Seiichi; Nakato, Teruyuki; Matsukawa, Kimihiro; Mutin, P Hubert; Sugahara, Yoshiyuki

    2014-02-04

    Organically modified niobate nanosheets are promising building blocks for the design of advanced hybrid materials. Nanosheets with controlled thickness and surface composition are important for precise structural design of the nanosheet-based materials. In this work, single-layered and double-layered niobate nanosheets functionalized by phenylphosphonate moieties were selectively prepared by interlayer grafting of A-type and B-type intercalation derivatives of potassium hexaniobate (K4Nb6O17·3H2O) with phenylphosphonic acid (PPA), followed by exfoliation by ultrasonication in acetonitrile. The interlayer grafting of PPA was monitored using X-ray diffraction (XRD), Fourier transform infrared (FTIR), and solid-state NMR spectroscopy, and the thicknesses of the exfoliated nanosheets were measured by atomic force microscopy (AFM). Transparent hybrid films were obtained by incorporating the single- and double-layered nanosheets into an epoxy matrix.

  9. Generating ultra-short energetic pulses with cascaded soliton compression in lithium niobate crystals

    DEFF Research Database (Denmark)

    Zhou, Binbin; Bache, Morten; Chong, A.

    2010-01-01

    By launching energetic femtosecond pulses in a lithium niobate crystal, the phase mismatched second-harmonic generation process compresses the 50 fs input pulse at 1250 nm to 30 fs through a soliton effect.......By launching energetic femtosecond pulses in a lithium niobate crystal, the phase mismatched second-harmonic generation process compresses the 50 fs input pulse at 1250 nm to 30 fs through a soliton effect....

  10. Domain patterning in lithium niobate using spontaneous backswitching

    Science.gov (United States)

    Batchko, Robert G.; Miller, Gregory D.; Shur, Vladimir Y.; Rumyantsev, Evgenii L.; Fejer, Martin M.; Byer, Robert L.

    1999-05-01

    In nonlinear optics applications employing quasi- phasematching, short pitch domain gratings are generally required for the generation of visible and ultraviolet light. The conventional electric-field poling method enables the fabrication of periodically-poled lithium niobate (PPLN) down to generally 6 micron-pitch domains in 0.5-mm-thick substrates. While such PPLN is useful for first-order second harmonic generation (SHG) of green wavelengths, shorter periods for blue and UV SHG have been difficult to obtain in 0.5-mm-thick substrates. Here we describe an enhanced electric-field poling technique for ferroelectric materials which utilizes spontaneous flip-back towards high-resolution and high-yield domain patterning.

  11. Study of structural differences between stoichiometric and congruent lithium niobate

    CERN Document Server

    Kling, A; Correia, J G; Da Silva, M F A; Diéguez, E; Agulló-López, F; Soares, J C

    1996-01-01

    The structural differences between stoichiometric and congruent (lithium deficient) lithium niobate single crystals were studied by RBS- and NRA-channeling as well as perturbed angular correlation (PAC) measurements. The d-PAC111Cd-PAC investigations point out that a second Li site can be detected in congruent material, while only one is present in stoichiometric. Channeling studies of different axes and the comparison of the results with computer simulations corroborated former indications that this additional lattice site can be attributed to the formation of ilmenite type stacking faults. A comparative study of the energy dependence of the dechanneling showed that a remarkable disorder is also present in the Nb sublattice of the congruent crystals and that these defects have a point-like character.

  12. Impedance spectroscopy of perovskite barium substituted lead zinc niobate ceramics

    Science.gov (United States)

    Himanshu, A. K.; Choudhary, B. K.; Gupta, D. C.; Bandyopadhayay, S. K.; Sinha, T. P.

    2010-03-01

    The complex perovskite lead barium zinc niobate, (Pb 1-xBa x)(Zn 1/3Nb 2/3)O 3 ceramic at x=0.25 was prepared by a columbite precursor method. The microstructure analysis was done by scanning electron microscope. The field dependences of the dielectric response and the conductivity were measured in a frequency range from 100 Hz to 1 MHz and in a temperature range from 110 to 310 K. The frequency dependence of the loss peak is found to obey Arrhenius law with activation energy of ∼0.019 eV. An analysis of the real and imaginary parts of the dielectric permittivity with frequency has been performed, assuming a distribution of relaxation times as confirmed by Cole-Cole plot. The frequency dependent electrical data were also analyzed in the framework of the conductivity and modulus formalism. Both these formalisms provided qualitative similarities in the relaxation times.

  13. Twinning structures in near-stoichiometric lithium niobate single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Shuhua; Chen, Yanfeng [Nanjing Univ. (China). Dept. of Materials Science and Engineering; Hu, Xiaobo; Yan, Tan; Liu, Hong; Wang, Jiyang [Shandong Univ., Jinan (China). State Key Lab. of Crystal Materials; Qin, Xiaoyong [Deqing Huaying Electronics Co. (China)

    2010-04-15

    A near-stoichiometric lithium niobate single crystal has been grown by the Czochralski method in a hanging double crucible with a continuous powder supply system. Twins were found at one of the three characteristic growth ridges of the as-grown crystal. The twin structure was observed and analyzed by transmission synchrotron topography. The image shifts {delta}X and {delta}Y in the transmission synchrotron topograph were calculated for the 3 anti 2 anti 12 and 0 anti 222 reflections based on results from high-resolution X-ray diffractometry. It is confirmed that one of the {l_brace}01 anti 1 anti 2{r_brace}{sub m} planes is the composition face of the twin and matrix crystals. The formation mechanism of these twins is discussed. (orig.)

  14. Ionoluminescence of trivalent rare-earth-doped strontium barium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Calvo del Castillo, H. [Departamento de Geologia y Geoquimica, Universidad Autonoma de Madrid, Modulo C-VI, Campus de Cantoblanco, 28049 Cantoblanco, Madrid (Spain); Universidad Nacional Automoma de Mexico, Instituto de Fisica, 04510 Ciudad Universitaria, Mexico D.F. (Mexico); Ruvalcaba, J.L. [Universidad Nacional Automoma de Mexico, Instituto de Fisica, 04510 Ciudad Universitaria, Mexico D.F. (Mexico); Bettinelli, M.; Speghini, A. [Dipartimento Scientifico e Tecnologico, Universita di Verona and INSTM, UdR Verona, Ca Vignal, Strada Le Grazie 15, I-37134 Verona (Italy); Barboza Flores, M. [Centro de Investigacion en Fisica, Universidad de Sonora, Hermosillo, Sonora (Mexico); Calderon, T. [Departamento de Geologia y Geoquimica, Universidad Autonoma de Madrid, Modulo C-VI, Campus de Cantoblanco, 28049 Cantoblanco, Madrid (Spain)], E-mail: tomas.calderon@uam.es; Jaque, D.; Garcia Sole, J. [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, 28049 Cantoblanco, Madrid (Spain)

    2008-05-15

    Ionoluminescence spectra for different rare-earth ion (Pr{sup 3+} and Eu{sup 3+})-activated Sr{sub x}Ba{sub 1-x}Nb{sub 2}O{sub 6} strontium barium niobate crystals (x=0.33 and 0.60) have been induced with a 3 MeV proton beam for a variety of beam current intensities (45, 40 and 20 nA). The proton-beam induced luminescent spectra have shown features associated with the presence of the rare-earth ion and some spectral features mostly related to the host crystal, which appear only for high beam current intensities. We have compared the ionoluminescence results to those obtained under UV light excitation (photoluminescence technique) where a direct excitation of the band gap would occur.

  15. Synthesis of transparent aqueous sols of colloidal layered niobate nanocrystals at room temperature.

    Science.gov (United States)

    Ban, Takayuki; Yoshikawa, Shogo; Ohya, Yutaka

    2011-12-01

    Transparent aqueous sols of colloidal tetramethylammonium niobate nanocrystals were synthesized by mixing tetramethylammonium hydroxide (TMAOH), niobium ethoxide, and water at TMAOH/Nb≥0.7 at room temperature. The X-ray diffraction patterns of the thin films prepared by evaporating the colloidal solutions on a glass substrate indicated that the colloidal niobate had a layered crystalline structure. Two types of layered structures are known as a layered niobate, i.e. M(4)Nb(6)O(17)·nH(2)O and MNb(3)O(8) (M=H, H(3)O, or alkaline metal). Raman spectra and electron diffraction suggested that the niobate nanocrystals were similar in crystal structure to M(4)Nb(6)O(17)·nH(2)O compounds. Moreover, when niobium oxide thin films were fabricated from the niobate colloidal solutions by the sol-gel method, oriented T-Nb(2)O(5) thin films, whose c-axis was parallel to the substrate surface, were obtained. The orientation of the thin films was probably attributed to the layered structure of the colloidal niobate nanocrystals. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. What is Potassium?

    Science.gov (United States)

    ... Workout Nutrition Timing Your Pre- and Post-Workout Nutrition weights and fruits Building Muscle on a Vegetarian Diet For Kids For Parents For Men For Women For Seniors What Is Potassium? Reviewed by Taylor Wolfram, MS, ...

  17. Optical and structural properties of single-crystal lithium niobate thin film

    Science.gov (United States)

    Han, Huangpu; Cai, Lutong; Hu, Hui

    2015-04-01

    High-refractive-index contrast, single-crystal lithium niobate thin films are emerging as a new platform for integrated optics. Such lithium niobate thin films are prepared using ion implantation and direct-wafer bonding to a SiO2 layer deposited on a LN substrate. However, the ion-implantation process can cause changes in the refractive index and result in lattice damage, and there are few studies on the optical and structural properties of lithium niobate thin film to compensate for this. In this paper, we reported that the refractive index of lithium niobate thin film can reach that of the bulk material by annealing in an oxygen atmosphere at 500 °C for 5 h. The experimental results of high-resolution X-ray diffraction (HRXRD) and Rutherford back-scattering spectrum (RBS) showed a good crystal lattice arrangement in the LN thin film. These experimental results confirmed that the refractive index and crystal-lattice structural properties of the lithium niobate thin film were similar to that of the bulk material. To demonstrate the application on integrated optics, a 1 μm wide photonic wire was fabricated and the near-field intensity profile at 1.55 μm wavelength was obtained and compared with the simulation result.

  18. Some peculiarities of Ti in-diffusion in lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Tsirlin, M.; Dariel, M. [CeLight Israel, Rotem Industrial Park, D.N.Arava, 86800 (Israel)

    2007-07-15

    The process of one- and two-dimensional Ti in-diffusion in lithium niobate, LiNbO{sub 3} (LN), single crystals of left angle x right angle and left angle z right angle orientations at 950-1060 C in oxygen/water vapor medium had been studied. In the case of one-dimensional diffusion, a flat diffusion front consisting of Ti solid solution in LN is formed. The process kinetics is described by Fick's equation for the case of a permanent source. In the case of two-dimensional Ti diffusion, the diffusion zone contour acquires the shape close to elliptical. The diffusion rate in the tangential direction is about an order of magnitude higher than in the normal direction. A model qualitatively describing such nontrivial character of the diffusion process is suggested. The model is based on: a) incongruent lithium evaporation out of LN at high temperatures; b) low thermodynamic activity of Li in LiTiO{sub 3} - product of Ti interaction with LN. These factors produce a significant nonlinearity of the process, since a strong chemical bond between Li and Ti in this phase leads to a mutual increase in their diffusive mobility. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Spectrophotometric determination of optical parameters of lithium niobate films

    Directory of Open Access Journals (Sweden)

    Nina S. Kozlova

    2017-09-01

    Full Text Available Lithium niobate films on silicon substrates have been synthesized by high-frequency magnetron sputtering of a target. The spectral dependences of the reflectance in the 300–700 nm range at small incidence angles and the angular dependence of p- and s-polarized light for a discrete set of wavelengths from 300 to 700 nm with wavelength increments of 50 nm, for angles of 1 arc deg, have been obtained using spectrophotometry. The refractive indicies, the film thickness and the extinction coefficients have been determined using a numerical method for solving inverse problems. The initial approximations for the solution of inverse problems have been defined using methods based on the estimation of the interference extrema positions in the reflection spectra. The resultant refractive indicies of the film differ from those typical of LiNbO3 single crystals. These differences are attributed to the structural disorder induced by the predominant crystallite orientation and the absorption in the film.

  20. Gold particle formation via photoenhanced deposition on lithium niobate

    Science.gov (United States)

    Zaniewski, A. M.; Meeks, V.; Nemanich, R. J.

    2017-05-01

    In this work, we report on a technique to reduce gold chloride into sub-micron particles and nanoparticles. We use photoelectron transfer from periodically polarized lithium niobate (PPLN) illuminated with above band gap light to drive the surface reactions required for the reduction and particle formation. The particle sizes and distributions on the PPLN surface are sensitive to the solution concentration, with inhibited nucleation and large particles (>150 nm) for both low (2E-8M to 9E-7M) and high (1E-5M to 1E-3M) concentrations of gold chloride. At midrange values of the concentration, nucleation is more frequent, resulting in smaller sized particles (<150 nm). We compare the deposition process to that for silver, which has been previously studied. We find that the reduction of gold chloride into nanoparticles is inhibited compared to silver ion reduction, due to the multi-step reaction required for gold particle formation. This also has consequences for the resulting deposition patterns: while silver deposits into nanowires along boundaries between areas with opposite signed polarizations, such patterning of the deposition is not observed for gold, for a wide range of concentrations studied (2E-8 to 1E-3M).

  1. Impedance spectroscopy of perovskite barium substituted lead zinc niobate ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Himanshu, A.K., E-mail: himanshu_ak@yahoo.co.i [Advanced Materials Laboratory, Variable Energy Cyclotron Centre, 1/AF Bidhannagar, Kolkata 700 064 (India); Choudhary, B.K. [University Department of Physics, Ranchi University, Jharkhand 834 001 (India); Gupta, D.C. [School of Studies in Physics, Jiwaji University, Gwalior, Madhya Pradesh 474 011 (India); Bandyopadhayay, S.K. [Advanced Materials Laboratory, Variable Energy Cyclotron Centre, 1/AF Bidhannagar, Kolkata 700 064 (India); Sinha, T.P. [Department of Physics, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700 009 (India)

    2010-03-15

    The complex perovskite lead barium zinc niobate, (Pb{sub 1-x}Ba{sub x})(Zn{sub 1/3}Nb{sub 2/3})O{sub 3} ceramic at x=0.25 was prepared by a columbite precursor method. The microstructure analysis was done by scanning electron microscope. The field dependences of the dielectric response and the conductivity were measured in a frequency range from 100 Hz to 1 MHz and in a temperature range from 110 to 310 K. The frequency dependence of the loss peak is found to obey Arrhenius law with activation energy of approx0.019 eV. An analysis of the real and imaginary parts of the dielectric permittivity with frequency has been performed, assuming a distribution of relaxation times as confirmed by Cole-Cole plot. The frequency dependent electrical data were also analyzed in the framework of the conductivity and modulus formalism. Both these formalisms provided qualitative similarities in the relaxation times.

  2. Recent Achievements on Photovoltaic Optoelectronic Tweezers Based on Lithium Niobate

    Directory of Open Access Journals (Sweden)

    Angel García-Cabañes

    2018-01-01

    Full Text Available This review presents an up-dated summary of the fundamentals and applications of optoelectronic photovoltaic tweezers for trapping and manipulation of nano-objects on the surface of lithium niobate crystals. It extends the contents of previous reviews to cover new topics and developments which have emerged in recent years and are marking the trends for future research. Regarding the theoretical description of photovoltaic tweezers, detailed simulations of the electrophoretic and dielectrophoretic forces acting on different crystal configurations are discussed in relation to the structure of the obtained trapping patterns. As for the experimental work, we will pay attention to the manipulation and patterning of micro-and nanoparticles that has experimented an outstanding progress and relevant applications have been reported. An additional focus is now laid on recent work about micro-droplets, which is a central topic in microfluidics and optofluidics. New developments in biology and biomedicine also constitute a relevant part of the review. Finally, some topics partially related with photovoltaic tweezers and a discussion on future prospects and challenges are included.

  3. Gold particle formation via photoenhanced deposition on lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Zaniewski, A.M., E-mail: azaniews@asu.edu; Meeks, V.; Nemanich, R.J.

    2017-05-31

    Highlights: • Gold chloride is reduced into solid gold nanoparticles at the surface of a polarized semiconductor. • Reduction processes are driven by ultraviolet light. • Gold nanoparticle and silver nanoparticle deposition patterns are compared. - Abstract: In this work, we report on a technique to reduce gold chloride into sub-micron particles and nanoparticles. We use photoelectron transfer from periodically polarized lithium niobate (PPLN) illuminated with above band gap light to drive the surface reactions required for the reduction and particle formation. The particle sizes and distributions on the PPLN surface are sensitive to the solution concentration, with inhibited nucleation and large particles (>150 nm) for both low (2E−8M to 9E−7M) and high (1E−5M to 1E−3M) concentrations of gold chloride. At midrange values of the concentration, nucleation is more frequent, resulting in smaller sized particles (<150 nm). We compare the deposition process to that for silver, which has been previously studied. We find that the reduction of gold chloride into nanoparticles is inhibited compared to silver ion reduction, due to the multi-step reaction required for gold particle formation. This also has consequences for the resulting deposition patterns: while silver deposits into nanowires along boundaries between areas with opposite signed polarizations, such patterning of the deposition is not observed for gold, for a wide range of concentrations studied (2E−8 to 1E−3M).

  4. Covalent grafting of phenylphosphonate on calcium niobate platelets.

    Science.gov (United States)

    Shori, Shailesh; Pellechia, Perry J; zur Loye, Hans-Conrad; Ploehn, Harry J

    2015-01-01

    This work explores covalent grafting of phenylphosphonate (PPA) onto exfoliated, protonated calcium niobate (HCN), a Dion-Jacobson layered perovskite. The specific hypothesis is that PPA can be readily grafted onto the face surfaces of exfoliated HCN, which has reactive apical oxygen atoms. Previous research has established the conditions required for full exfoliation of HCN in aqueous solutions of tetrabutylammonium hydroxide (TBAOH), denoted as TBACN. This work first explores the effect of reflux conditions on the dispersion state of TBACN suspensions, and then investigates PPA grafting onto both non-exfoliated HCN and exfoliated TBACN dispersed in deionized (DI) water, TBA solution, and various alcohols. The products are characterized by a variety of techniques including light scattering to assess the TBACN dispersion state, (31)P MAS NMR to confirm PPA grafting, and XPS to estimate PPA grafted amounts. The results confirm the grafting of PPA on HCN and TBACN, quantify the extent of PPA grafting, and identify various grafting modes (mono-, bi-, and tridentate). All of these aspects are found to be dependent on the layered materials' exfoliation state, suspension processing conditions, and solvent composition. The results are rationalized in terms of a plausible mechanism of the grafting process. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Control of Intrinsic Defects in Lithium Niobate Single Crystal for Optoelectronic Applications

    Directory of Open Access Journals (Sweden)

    Rajeev Bhatt

    2017-01-01

    Full Text Available A single crystal of lithium niobate is an important optoelectronic material. It can be grown from direct melt only in a lithium deficient non-stoichiometric form as its stoichiometric composition exhibits incongruent melting. As a result it contains a number of intrinsic point defects such as Li-vacancies, Nb antisites, oxygen vacancies, as well as different types of polarons and bipolarons. All these defects adversely influence its optical and ferroelectric properties and pose a deterrent to the effective use of this material. Hence, controlling the defects in lithium niobate has been an exciting topic of research and development over the years. In this article we discuss the different methods of controlling the intrinsic defects in lithium niobate and a comparison of the effect of these methods on the crystalline quality, stoichiometry, optical absorption in the UV-vis region, electronic band-gap, and refractive index.

  6. Preparation of porous solids composed of layered niobate walls from colloidal mixtures of niobate nanosheets and polystyrene spheres.

    Science.gov (United States)

    Miyamoto, Nobuyoshi; Kuroda, Kazuyuki

    2007-09-01

    Macroporous solids with crystalline layered walls were fabricated from colloidal mixtures of size-controlled niobate nanosheets and polystyrene spheres. The macroporous solids, obtained after burning off the spheres, were characterized by scanning electron microscopy and X-ray diffraction. The obtained structures strongly depended on the lateral dimension L of the nanosheets used. When small nanosheets (L=100 nm) were used, partly ordered macroporous solids with interconnected pores were obtained, whereas sponge-like random macroporous structures were obtained with larger nanosheets (L=190 and 270 nm). Peapod-like hollow structures were obtained when we used small (L=190 nm) and very large (L=3 microm) nanosheets at the same time. The microstructure of the pore walls was controllable by changing the calcination conditions. The walls were composed of propylammonium/K(4)Nb(6)O(17) intercalation compound which has a layered structure with exchangeable cations in the interlayer space, stable up to 350 degrees C for 6 h on calcination. The walls were converted to crystalline K(8)Nb(18)O(49) after calcination at 500 degrees C for 6 h.

  7. Neural synchronization via potassium signaling

    DEFF Research Database (Denmark)

    Postnov, Dmitry E; Ryazanova, Ludmila S; Mosekilde, Erik

    2006-01-01

    Using a relatively simple model we examine how variations of the extracellular potassium concentration can give rise to synchronization of two nearby pacemaker cells. With the volume of the extracellular space and the rate of potassium diffusion as control parameters, the dual nature...... junctional coupling, potassium signaling gives rise to considerable changes of the cellular response to external stimuli....

  8. Writing single-mode waveguides in lithium niobate by ultra-low intensity solitons

    Energy Technology Data Exchange (ETDEWEB)

    Fazio, E. [Universita degli Studi di Roma ' La Sapienza' and INFM, I-00161 Rome (Italy)]. E-mail: eugenio.fazio@uniromal.it; Ramadan, W. [Physics department, Faculty of Science, Mansoura University, Damietta (Egypt); Petris, A. [Romanian Center of Excellence in Photonics, R-76900 Bucharest (Romania); Chauvet, M. [Laboratoire d' optique P.M. Duffieux, Universite de Franche Comte, Besancon (France); Bosco, A. [Universita degli Studi di Roma ' La Sapienza' and INFM, I-00161 Rome (Italy); Vlad, V.I. [Romanian Center of Excellence in Photonics, R-76900 Bucharest (Romania); Bertolotti, M. [Universita degli Studi di Roma ' La Sapienza' and INFM, I-00161 Rome (Italy)

    2005-07-30

    Optical waveguides can be conveniently written in photorefractive materials by using spatial solitons. We have generated bright spatial solitons inside lithium niobate which allow single-mode light propagation. Efficient waveguides have been generated with CW light powers as high as few microwatts. According to the soliton formation, waveguides can be formed with different shapes. Due to the slow response time of the lithium niobate, both for soliton formation and relaxation, the soliton waveguide remains memorised for a long time, of the order of months.

  9. Optimal design of DC-based polarization beam splitter in lithium niobate on insulator

    Science.gov (United States)

    Gong, Zisu; Yin, Rui; Ji, Wei; Wang, Junbao; Wu, Chonghao; Li, Xiao; Zhang, Shicheng

    2017-08-01

    We propose a DC-based polarization beam splitter (PBS) in lithium niobate on insulator (LNOI). Utilizing the high birefringence property of Lithium Niobate (LiNbO3, LN), the device is achieved by simple structure in a short length. With the use of beam propagation method (BPM), the simulation results show that the device has a good performance for the separation of TE and TM polarizations with a high extinction ratio (about 35 dB). The simulated fabrication tolerance for the variation of the waveguide width is about 100 nm and the bandwidth is about 65 nm when the extinction ratio is higher than 10 dB.

  10. Second harmonic generation in nano-structured thin-film lithium niobate waveguides.

    Science.gov (United States)

    Wang, Cheng; Xiong, Xiao; Andrade, Nicolas; Venkataraman, Vivek; Ren, Xi-Feng; Guo, Guang-Can; Lončar, Marko

    2017-03-20

    Integrated thin-film lithium niobate platform has recently emerged as a promising candidate for next-generation, high-efficiency wavelength conversion systems that allow dense packaging and mass-production. Here we demonstrate efficient, phase-matched second harmonic generation in lithographically-defined thin-film lithium niobate waveguides with sub-micron dimensions. Both modal phase matching in fixed-width waveguides and quasi-phase matching in periodically grooved waveguides are theoretically proposed and experimentally demonstrated. Our low-loss (~3.0 dB/cm) nanowaveguides possess normalized conversion efficiencies as high as 41% W-1cm-2.

  11. Efficient second harmonic generation in χ(2) profile reconfigured lithium niobate thin film

    Science.gov (United States)

    Cai, Lutong; Wang, Yiwen; Hu, Hui

    2017-03-01

    Second harmonic wave was efficiently generated in proton exchanged lithium niobate thin film channel waveguides. Modal dispersion phase matching was achieved between two guided modes at pump and second-harmonic wavelengths with the same polarization, enabling using the largest second-order nonlinear component d33. The χ(2) profile in the lithium niobate thin film was reconfigured by proton exchange, leading to significantly enhanced modal overlap integral between the interacting modes. Normalized conversion efficiency up to 48% W-1 cm-2 was achieved in experiments.

  12. Determining the sign of a polar surface of lithium niobate crystal by UV reflectance spectroscopy

    Science.gov (United States)

    Paranin, V. D.; Pantelei, E.

    2017-01-01

    We propose to reveal the + Z and- Z surfaces of a polar cut lithium niobate crystal by measuring its UV reflection spectrum. By the example of a congruent lithium niobate, it is shown that the intensities of light reflection from polar crystal surfaces of different signs in the region of 190—260 nm differ by up to several percent. The depth of short-wave radiation penetration into surface layers of the crystal in the spectral range of intrinsic absorption is estimated. It is shown that the proposed method can be used for determining the surface signs of polar crystal layers with thicknesses from several dozen to several hundred microns.

  13. Tunable dual-wavelength filter and its group delay dispersion in domain-engineered lithium niobate

    Directory of Open Access Journals (Sweden)

    Guang-hao Shao

    2016-12-01

    Full Text Available A tunable dual-wavelength filter is experimentally demonstrated in domain-engineered lithium niobate. Application of an electric field on the y-surfaces of the sample results in the optical axes rotating clockwise and anticlockwise, which makes selective polarization rotation. The quasi phase-matching wavelengths could be adjusted through suitable domain design. A unique dual valley spectrum is obtained in a periodically poled lithium niobate structure with a central defect if the sample is placed between two parallel polarizers. The expected bandwidth could be varied from ∼1 nm to ∼40 nm. Moreover, both the spectral response and group delay dispersion could be engineered.

  14. Growth, defect structure, and THz application of stoichiometric lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Lengyel, K.; Péter, Á.; Kovács, L.; Corradi, G.; Dravecz, G.; Hajdara, I.; Szaller, Zs.; Polgár, K. [Wigner Research Centre for Physics, Hungarian Academy of Sciences, 1121 Budapest, Konkoly-Thege M. út 29-33 (Hungary); Pálfalvi, L.; Unferdorben, M. [Institute of Physics, University of Pécs, 7624 Pécs, Ifjúság útja 6 (Hungary); Hebling, J. [Institute of Physics, University of Pécs, 7624 Pécs, Ifjúság útja 6 (Hungary); MTA-PTE High Field Terahertz Research Group, 7624 Pécs (Hungary)

    2015-12-15

    Owing to the extraordinary richness of its physical properties, congruent lithium niobate has attracted multidecade-long interest both for fundamental science and applications. The combination of ferro-, pyro-, and piezoelectric properties with large electro-optic, acousto-optic, and photoelastic coefficients as well as the strong photorefractive and photovoltaic effects offers a great potential for applications in modern optics. To provide powerful optical components in high energy laser applications, tailoring of key material parameters, especially stoichiometry, is required. This paper reviews the state of the art of growing large stoichiometric LiNbO{sub 3} (sLN) crystals, in particular, the defect engineering of pure and doped sLN with emphasis on optical damage resistant (ODR) dopants (e.g., Mg, Zn, In, Sc, Hf, Zr, Sn). The discussion is focused on crystals grown by the high temperature top seeded solution growth (HTTSSG) technique using alkali oxide fluxing agents. Based on high-temperature phase equilibria studies of the Li{sub 2}O–Nb{sub 2}O{sub 5}–X{sub 2}O ternary systems (X = Na, K, Rb, Cs), the impact of alkali homologue additives on the stoichiometry of the lithium niobate phase will be analyzed, together with a summary of the ultraviolet, infrared, and far-infrared absorption spectroscopic methods developed to characterize the composition of the crystals. It will be shown that using HTTSSG from K{sub 2}O containing flux, crystals closest to the stoichiometric composition can be grown characterized by a UV-edge position of at about 302 nm and a single narrow hydroxyl band in the IR with a linewidth of less than 3 cm{sup −1} at 300 K. The threshold concentrations for ODR dopants depend on crystal stoichiometry and the valence of the dopants; Raman spectra, hydroxyl vibration spectra, and Z-scan measurements prove to be useful to distinguish crystals below and above the photorefractive threshold. Crystals just above the threshold are

  15. Ultraviolet photorefraction at 325 nm in doped lithium niobate crystals

    Science.gov (United States)

    Xin, Feifei; Zhang, Guoquan; Bo, Fang; Sun, Haifeng; Kong, Yongfa; Xu, Jingjun; Volk, Tatyana; Rubinina, Natalia M.

    2010-02-01

    We studied the photorefractive effect of lithium niobate (LiNbO3) doped with Mg, Zn, In, Hf, or codoped with Mg and Fe at an ultraviolet (UV) wavelength down to 325 nm. It is found that the UV photorefraction of LiNbO3 doped with Mg, Zn, In, or Hf was enhanced significantly as compared to that of the nominally pure LiNbO3. Our results show that the property of resistance against photorefraction in highly Mg, Zn, In, or Hf doped LiNbO3 is true only in the visible and near-infrared wavelength range. By contrast, these crystals exhibit excellent photorefractive characteristics at UV wavelength of 325 nm, even better than those at 351 nm. For example, the photorefractive two-wave coupling gain coefficient Γ and the photorefractive recording sensitivity at 325 nm were measured to be ˜38 cm-1 and 37.7 cm/J, respectively, in a LiNbO3 crystal doped with 9 mol % Zn. The photorefractive response time of a Mg:LiNbO3 with a 9 mol % Mg was measured to be 73 ms with a total recording intensity of 614 mW/cm2 at 325 nm. In highly Mg, Zn, In, or Hf doped LiNbO3 crystals, diffusion dominates over photovoltaic effect and electrons are the dominant charge carriers in UV photorefraction at 325 nm. The results are also of interest to the study on the defect structure of LiNbO3 near to the absorption edge.

  16. Lightning arrestor connector lead magnesium niobate qualification pellet test procedures.

    Energy Technology Data Exchange (ETDEWEB)

    Tuohig, W. (Honeywell FM& T, Kansas City, MO); Mahoney, Patrick A.; Tuttle, Bruce Andrew; Wheeler, Jill Susanne

    2009-02-01

    Enhanced knowledge preservation for DOE DP technical component activities has recently received much attention. As part of this recent knowledge preservation effort, improved documentation of the sample preparation and electrical testing procedures for lead magnesium niobate--lead titanate (PMN/PT) qualification pellets was completed. The qualification pellets are fabricated from the same parent powders used to produce PMN/PT lightning arrestor connector (LAC) granules at HWF&T. In our report, the procedures for fired pellet surface preparation, electrode deposition, electrical testing and data recording are described. The dielectric measurements described in our report are an information only test. Technical reasons for selecting the electrode material, electrode size and geometry are presented. The electrical testing is based on measuring the dielectric constant and dissipation factor of the pellet during cooling from 280 C to 220 C. The most important data are the temperature for which the peak dielectric constant occurs (Curie Point temperature) and the peak dielectric constant magnitude. We determined that the peak dielectric constant for our procedure would be that measured at 1 kHz at the Curie Point. Both the peak dielectric constant and the Curie point parameters provide semi-quantitative information concerning the chemical and microstructural homogeneity of the parent material used for the production of PMN/PT granules for LACs. Finally, we have proposed flag limits for the dielectric data for the pellets. Specifically, if the temperature of the peak dielectric constant falls outside the range of 250 C {+-} 30 C we propose that a flag limit be imposed that will initiate communication between production agency and design agency personnel. If the peak dielectric constant measured falls outside the range 25,000 {+-} 10,000 we also propose that a flag limit be imposed.

  17. Annealing behaviour of MeV erbium implanted lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Gortmaker, P.; McCallum, J.C. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1993-12-31

    Lithium niobate (LiNbO{sub 3}) is a crystalline ceramic commonly used in the fabrication of optoelectronic devices. Recently, rare earth doping of LiNbO{sub 3} has become a topic of particular interest. The electronic configuration of rare earth elements such as Erbium (Er) and Neodymium (Nd) allows them to lase in nearly any host matrix making fabrication of a whole range of new optoelectronic devices possible. At present, the doping technique, for LiNbO{sub 3} are centred upon diffusion technology, but the diffusion profiles for the rare earths are not generally well-matched to the optical modes of the device. The aim of this research is to develop MeV implantation and annealing conditions of rare earth doped LiNbO{sub 3} that would be compatible with optoelectronic device fabrication. To determine the characteristics of the rare earth elements in the LiNbO{sub 3} host material over the depth range of interest in optoelectronic device applications, high energy Rutherford backscattering spectrometry and ion channeling (RBS-C) must be used. Presented here are the Er depth profile and lattice damage results obtained from 5 MeV RBS-C measurements on samples of LiNbO{sub 3} implanted with various doses of MeV Erbium and subsequently thermally annealed at a temperature of 1000 deg C. It was found that there is a peak implant concentration (2 x 10{sup 16} Er/cm{sup 2}) for which erbium no longer goes substitutional in the lattice, and the implantation damage is not fully removed by annealing. 8 refs., 3 figs.

  18. Structural refinement and optical band gap studies of manganese-doped modified sodium potassium lithium niobate lead — piezoelectric ceramics

    Science.gov (United States)

    Mishra, S. K.; Mishra, R. K.; Brajesh, Kumar; Ray, Rajyavardhan; Himanshu, A. K.; Pandey, H. K.; Singh, N. K.

    2014-05-01

    Li-doped NKLN ceramic (Na0.5 K0.5)0.935Li0.065NbO3 (NKLN935) in pure and MnO2 doped compositions have been revisited to carry out a detailed analysis of the structural and optical properties. Rietveld analysis of the X-ray diffraction (XRD) pattern reveals the system to be tetragonal (space group P4mm). UV-Visible (UV-Vis) spectroscopy and an equivalent Kubelka-Munk function is used to obtain the optical band gap values. It is reported that with increasing Mn doping, the band gap values decreases, which has been analyzed and understood in terms of the tetragonal structure and is found to be consistent with dielectric properties.

  19. Broadly Tunable, Mode-Hop-Tuned cw Optical Parametric Oscillator Based on Periodically Poled Lithium Niobate

    Science.gov (United States)

    Bisson, Scott E.; Armstrong, Karla M.; Kulp, Thomas J.; Hartings, Matthew

    2001-11-01

    We describe a broadly tunable, cw optical parametric oscillator (OPO) based on periodically poled lithium niobate. The OPO can be tuned over a broad region in the mid IR (2900 -3100 cm-1 ) covering the important C -H stretch region while a high spectral resolution ( volatile organic compounds.

  20. Periodically-poled lithium niobate - a 'designer' material for nonlinear optics

    OpenAIRE

    Hanna, D.C.

    1999-01-01

    Many of the previous limitations of nonlinear optical materials have now been swept aside with the recent advent of quasi-matched materials such as periodically-poled lithium niobate (PPLN). This talk, starting with an introduction to the basic principles of quasi-phase-matching will review the progress made in developing devices based on PPLN, and survey future prospects.

  1. Flexible Piezoelectric Touch Sensor by Alignment of Lead-Free Alkaline Niobate Microcubes in PDMS

    NARCIS (Netherlands)

    Deutz, D.B.; Mascarenhas, N.T.; Schelen, J.B.J.; Leeuw, D.M. de; Zwaag, S. van der; Groen, P.

    2017-01-01

    A highly sensitive, lead-free, and flexible piezoelectric touch sensor is reported based on composite films of alkaline niobate K0.485Na0.485Li0.03NbO3 (KNLN) powders aligned in a polydimethylsiloxane (PDMS) matrix. KNLN powder is fabricated by solid-state sintering and consists of microcubes. The

  2. Safe disposal of radioactive iodide ions from solutions by Ag2O grafted sodium niobate nanofibers.

    Science.gov (United States)

    Mu, Wanjun; Li, Xingliang; Liu, Guoping; Yu, Qianhong; Xie, Xiang; Wei, Hongyuan; Jian, Yuan

    2016-01-14

    Radioactive iodine isotopes are released into the environment by the nuclear industry and medical research institutions using radioactive materials, and have negative effects on organisms living within the ecosystem. Thus, safe disposal of radioactive iodine is necessary and crucial. For this reason, the uptake of iodide ions was investigated in Ag2O nanocrystal grafted sodium niobate nanofibers, which were prepared by forming a well-matched phase coherent interface between them. The resulting composite was applied as an efficient adsorbent for I(-) anions by forming an AgI precipitate, which also remained firmly attached to the substrates. Due to their one-dimensional morphology, the new adsorbents can be easily dispersed in liquids and readily separated after purification. This significantly enhances the adsorption efficiency and reduces the separation costs. The change in structure from the pristine sodium niobate to Ag2O anchored sodium niobate and to the used adsorbent was examined by using various characterization techniques. The effects of Ag(+) concentration, pH, equilibration time, ionic strength and competing ions on the iodide ion removal ability of the composite were studied. The Ag2O nanocrystal grafted sodium niobate adsorbent showed a high adsorption capacity and excellent selectivity for I(-) anions in basic solutions. Our results are useful for the further development of improved adsorbents for removing I(-) anions from basic wastewater.

  3. Etude par spectroscopie vibrationnelle des niobates de sodium et d'argent de structure perovskite

    Science.gov (United States)

    Husson, E.; Repelin, Y.

    Infrared and Raman spectra of the niobates NaNbO 3 and AgNbO 3 of perovskite structure are analysed. An assignment of the frequencies is proposed. The influence of the antiferroelectric direction upon the NbO bonds is shown, as the influence of the A cation upon the AO and NbO bonds.

  4. Efficient Femtosecond Mid-infrared Pulse Generation by Dispersive Wave Radiation in Bulk Lithium Niobate Crystal

    DEFF Research Database (Denmark)

    Zhou, Binbin; Guo, Hairun; Bache, Morten

    2014-01-01

    We experimentally demonstrate efficient mid-infrared pulse generation by dispersive wave radiation in bulk lithium niobate crystal. Femtosecond mid-IR pulses centering from 2.8-2.92 μm are generated using the single pump wavelengths from 1.25-1.45 μm. © 2014 Optical Society of America...

  5. Shape manipulation of ion irradiated Ag nanoparticles embedded in lithium niobate

    NARCIS (Netherlands)

    Wolf, S.; Rensberg, J.; Johannes, A.; Thomae, R.; Smit, F.; Neveling, R.; Moodley, M.; Bierschenk, T.; Rodriquez, M.; Afra, B.; Hasan, Shakeeb Bin; Rockstuhl, C.; Ridgway, M.; Bharuth-Ram, K.; Ronning, C.

    2016-01-01

    Spherical silver nanoparticles were prepared by means of ion beam synthesis in lithium niobate. The embedded nanoparticles were then irradiated with energetic 84Kr and 197Au ions, resulting in different electronic energy losses between 8.1 and 27.5 keV nm−1 in the top layer of the samples. Due to

  6. Interaction of light with impurities in lithium niobate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Schwesyg, Judith Renate Marie-Luise

    2011-06-06

    Congruent lithium niobate (LiNbO{sub 3}) and 5-mol% MgO-doped LiNbO{sub 3} (MgO:LN) crystals are widely used as nonlinear-optical crystals in frequency-conversion devices due to their large nonlinear-optic coefficients. These devices usually require high optical pump powers, but absorption of photons by impurities limits their usability due to heat accumulation that leads to thermo-optic refractive index changes. These refractive index changes distort the beam shape and disturb the phase-matching condition. Furthermore pyroelectric fields can build up. In this thesis the residual optical absorption in congruent LiNbO{sub 3} (CLN) and MgO:LN crystals is studied. Absorption spectra of CLN and MgO:LN crystals between 400-2000 nm reveal a residual absorption up to 0.04 cm{sup -1}. This absorption is mainly caused by transition metal impurities. Between 2300-2800 nm unknown hydrogen absorption bands in CLN and MgO:LN are revealed on the order of 0.001 cm{sup -1}. High-temperature annealing is applied to the CLN and MgO:LN crystals, which decreases optical absorption by up to one order of magnitude. As an application, the operation of a 1550-nm pumped singly-resonant CW optical parametric oscillator, resonant around 2600 nm, using a low-loss, periodically-poled, annealed CLN crystal is demonstrated. Another issue that affects CLN is photorefractive damage (PRD), i.e. light-induced refractive index changes. In contrast, MgO:LN crystals do not suffer from PRD even at high optical intensities. However, it is shown in this thesis that PRD can occur within seconds in MgO:LN, using green laser light at light intensity levels as low as 100 mW/cm{sup 2}, if the crystal is heated by several degrees Celsius during or before illumination. Photorefractive damage does not occur in CLN crystals under the same conditions. We show that the pyroelectric effect together with an elevated photoconductivity compared to that of CLN causes this beam distortion and that this effect also

  7. 640-Gbit/s data transmission and clock recovery using an ultrafast periodically poled lithium niobate device

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Gomez-Agis, F.; Ware, C.

    2009-01-01

    This paper presents the first demonstration of the use of a periodically poled lithium niobate device for signal processing at 640 Gbit/s. Clock recovery is performed successfully using the lithium niobate device, and the clock signal is used to control fiber-based demultiplexer. The full 640-Gbi....../s system gives error-free performance with no pattern dependence and there is less than 1-dB power penalty after 50-km fiber transmission....

  8. Experimental and simulated performance of lithium niobate 1-3 piezocomposites for 2 MHz non-destructive testing applications.

    Science.gov (United States)

    Kirk, K J; Schmarje, N

    2013-01-01

    Lithium niobate piezocomposites have been investigated as the active element in high temperature resistant ultrasonic transducers for non-destructive testing applications up to 400°C. Compared to a single piece of lithium niobate crystal they demonstrate shorter pulse length by 3×, elimination of lateral modes, and resistance to cracking. In a 1-3 connectivity piezocomposite for high temperature use (200-400°C), lithium niobate pillars are embedded in a matrix of flexible high temperature sealant or high temperature cement. In order to better understand the design principles and constraints for use of lithium niobate in piezocomposites experiments and modelling have been carried out. For this work the lithium niobate piezocomposites were investigated at room temperature so epoxy filler was used. 1-3 connectivity piezocomposite samples were prepared with z-cut lithium niobate, pillar width 0.3-0.6mm, sample thickness 1-4mm, pillar aspect ratio (pillar height/width) 3-6, volume fraction 30 and 45%. Operating frequency was 1-2MHz. Experimental measurements of impedance magnitude and resonance frequency were compared with 3-D finite element modelling using PZFlex. Resonance frequencies were predicted within 0.05MHz and impedance magnitude within 2-5% for samples with pillar aspect ratio ≥3 for 45% volume fraction and pillar aspect ratio ⩾6 for 30% volume fraction. Laser vibrometry of pulse excitation of piezocomposite samples in air showed that the lithium niobate pillars and the epoxy filler moved in phase. Experiment and simulation showed that the thickness mode coupling coefficient k(t) of the piezocomposite was maintained at the lithium niobate bulk value of approximately 0.2 down to a volume fraction of 30%, consistent with calculations using the (Smith and Auld, 1991) model for piezocomposites. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. High-energy Few-cycle Pulses Directly Generated from Strongly Phase-mismatched Lithium Niobate Crystal

    DEFF Research Database (Denmark)

    Zhou, Binbin; Chong, A.; Wise, F.W.

    2012-01-01

    We show that effective soliton compression can be realized in strongly phase-mismatched quadratic media. Sub-15 fs pulses are experimentally generated directly from 10-mm-long bulk lithium niobate crystal by 120-fs input pulses at 1300 nm.......We show that effective soliton compression can be realized in strongly phase-mismatched quadratic media. Sub-15 fs pulses are experimentally generated directly from 10-mm-long bulk lithium niobate crystal by 120-fs input pulses at 1300 nm....

  10. Thermo-electric oxidization of iron in lithium niobate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Falk, Matthias

    2007-07-01

    Lithium niobate crystals (LiNbO{sub 3}) are a promising material for nonlinear-optical applications like frequency conversion to generate visible light, e.g., in laser displays, but their achievable output power is greatly limited by the ''optical damage'', i.e., light-induced refractive-index changes caused by excitation of electrons from iron impurities and the subsequent retrapping in unilluminated areas of the crystal. The resulting space-charge fields modify the refractive indices due to the electro-optic effect. By this ''photorefractive effect'' the phase-matching condition, i.e., the avoidance of destructive interference between light generated at different crystal positions due to the dispersion of the fundamental wave and the converted wave, is disturbed critically above a certain light intensity threshold. The influence of annealing treatments conducted in the presence of an externally applied electric field (''thermo-electric oxidization'') on the valence state of iron impurities and thereby on the optical damage is investigated. It is observed that for highly iron-doped LiNbO{sub 3} crystals this treatment leads to a nearly complete oxidization from Fe{sup 2+} to Fe{sup 3+} indicated by the disappearance of the absorption caused by Fe{sup 2+}. During the treatment an absorption front forms that moves through the crystal. The absorption in the visible as well as the electrical conductivity are decreased by up to five orders of magnitude due to this novel treatment. The ratio of the Fe{sup 2+} concentration to the total iron concentration - a measure for the strength of the oxidization - is in the order of 10{sup -6} for oxidized crystals whereas it is about 10{sup -1} for untreated samples. Birefringence changes are observed at the absorption front that are explained by the removal of hydrogen and lithium ions from the crystal that compensate for the charges of the also removed electrons from

  11. Dietary reference values for potassium

    DEFF Research Database (Denmark)

    Sjödin, Anders Mikael

    2016-01-01

    Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) derives dietary reference values (DRVs) for potassium. The Panel decides to set DRVs on the basis of the relationships between potassium intake and blood pressure and stroke...

  12. Potassium supplementation and heart rate

    NARCIS (Netherlands)

    Gijsbers, L.; Molenberg, Famke; Bakker, S.J.L.; Geleijnse, J.M.

    2016-01-01

    Background and aims: Increasing the intake of potassium has been shown to lower blood pressure, but whether it also affects heart rate (HR) is largely unknown. We therefore assessed the effect of potassium supplementation on HR in a meta-analysis of randomized controlled trials. Methods and

  13. Cardiac potassium channel subtypes

    DEFF Research Database (Denmark)

    Schmitt, Nicole; Grunnet, Morten; Olesen, Søren-Peter

    2014-01-01

    About 10 distinct potassium channels in the heart are involved in shaping the action potential. Some of the K(+) channels are primarily responsible for early repolarization, whereas others drive late repolarization and still others are open throughout the cardiac cycle. Three main K(+) channels...... drive the late repolarization of the ventricle with some redundancy, and in atria this repolarization reserve is supplemented by the fairly atrial-specific KV1.5, Kir3, KCa, and K2P channels. The role of the latter two subtypes in atria is currently being clarified, and several findings indicate...... that they could constitute targets for new pharmacological treatment of atrial fibrillation. The interplay between the different K(+) channel subtypes in both atria and ventricle is dynamic, and a significant up- and downregulation occurs in disease states such as atrial fibrillation or heart failure...

  14. Annealed proton exchanged optical waveguides in lithium niobate differences between the X- and Z-cuts

    CERN Document Server

    Nekvindova, P; Cervena, J; Budnar, M; Razpet, A; Zorko, B; Pelicon, P; 10.1016/S0925-3467(01)00186-0

    2002-01-01

    Summarizes results and assessments of our systematic fabrication and characterization of proton exchanged (PE) and annealed proton exchanged (APE) waveguides in lithium niobate. This study focused on different behavior of crystallographically diverse X(1120) and Z (0001) substrate cuts during waveguide fabrication, and differences in characteristics of the resulting waveguides. Non-toxic adipic acid was used as a proton source, and the waveguides properties were defined by mode spectroscopy (waveguide characteristics) and neutron depth profiling (NDP, lithium concentration and distribution), infrared vibration spectra and elastic recoil detection analysis (ERDA, concentration and depth distribution of hydrogen). It was discovered that the X-cut structure is more permeable for moving particles (lithium and hydrogen ions), which leads to a higher effectiveness of the PE process within the X-cut. The explanation of this phenomenon is based on fitting X-cut orientation towards cleavage planes of lithium niobate c...

  15. Origin of light-deflection in lithium niobate and lithium tantalate under electric field.

    Science.gov (United States)

    Guilbert, Laurent

    2009-06-22

    The deflection of light reported by Müller et al. in lithium niobate [Appl. Phys. B 78, 367-370] and lithium tantalate [Appl. Optics 43 (34), 6344-6347] under electric field originates from refraction at domain-walls, like in ferroelastics. In ferroelectrics the optical discontinuity takes place at domain-walls as a consequence of the electro-optic effect. The theoretical deflection angle calculated from Snell's law is proportional to the square root of the electric field and matches the experimental results reported by Müller et al. for lithium niobate. The finite domain-wall thickness mentioned by the authors is not involved in the deflection phenomenon.

  16. Influence of UV light and heat on the ferroelectric properties of lithium niobate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Steigerwald, Hendrik

    2011-08-15

    One of the most important non-linear-optical materials is lithium niobate, due to its ease of fabrication, robustness, transparency in the visible-to-infrared and excellent nonlinear properties. In this thesis the issue of tailoring ferroelectric domain structures in lithium niobate crystals is approached from two sides: interaction of defect structures inside the crystal with growing ferroelectric domains is investigated and also actual domain patterning on all crystal faces by different methods is performed. Special emphasis is given to the Mg-doped material. The fundamental understanding and the methods of domain patterning developed in this thesis are then used to obtain tailored domain structures that meet the requirements of their intended application in non-linear optics. (orig.)

  17. Shape manipulation of ion irradiated Ag nanoparticles embedded in lithium niobate

    Science.gov (United States)

    Wolf, Steffen; Rensberg, Jura; Johannes, Andreas; Thomae, Rainer; Smit, Frederick; Neveling, Retief; Moodley, Mathew; Bierschenk, Thomas; Rodriguez, Matias; Afra, Boshra; Hasan, Shakeeb Bin; Rockstuhl, Carsten; Ridgway, Mark; Bharuth-Ram, Krish; Ronning, Carsten

    2016-04-01

    Spherical silver nanoparticles were prepared by means of ion beam synthesis in lithium niobate. The embedded nanoparticles were then irradiated with energetic 84Kr and 197Au ions, resulting in different electronic energy losses between 8.1 and 27.5 keV nm-1 in the top layer of the samples. Due to the high electronic energy losses of the irradiating ions, molten ion tracks are formed inside the lithium niobate in which the elongated Ag nanoparticles are formed. This process is strongly dependent on the initial particle size and leads to a broad aspect ratio distribution. Extinction spectra of the samples feature the extinction maximum with shoulders on either side. While the maximum is caused by numerous remaining spherical nanoparticles, the shoulders can be attributed to elongated particles. The latter could be verified by COMSOL simulations. The extinction spectra are thus a superposition of the spectra of all individual particles.

  18. Periodic domain patterning by electron beam of proton exchanged waveguides in lithium niobate

    Science.gov (United States)

    Chezganov, D. S.; Vlasov, E. O.; Neradovskiy, M. M.; Gimadeeva, L. V.; Neradovskaya, E. A.; Chuvakova, M. A.; Tronche, H.; Doutre, F.; Baldi, P.; De Micheli, M. P.; Shur, V. Ya.

    2016-05-01

    Formation of domain structure by electron beam irradiation in congruent lithium niobate covered by surface dielectric layer with planar and channel waveguides produced by Soft Proton Exchange (SPE) process has been studied. Formation of domains with arbitrary shapes as a result of discrete switching has been revealed. The fact was attributed to ineffective screening of depolarization field in the crystals with a surface layer modified by SPE process. The dependences of the domain sizes on the dose and the distance between irradiated areas have been revealed. Finally, we have demonstrated that electron beam irradiation of lithium niobate crystals with surface resist layer can produce high quality periodical domain patterns after channel waveguide fabrication. Second harmonic generation with normalized nonlinear conversion efficiency up to 48%/(W cm2) has been achieved in such waveguides.

  19. Periodic domain patterning by electron beam of proton exchanged waveguides in lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Chezganov, D. S., E-mail: chezganov.dmitry@urfu.ru; Shur, V. Ya. [Institute of Natural Sciences, Ural Federal University, 620000 Ekaterinburg (Russian Federation); Labfer Ltd., 620014 Ekaterinburg (Russian Federation); Vlasov, E. O.; Neradovskiy, M. M.; Gimadeeva, L. V.; Neradovskaya, E. A.; Chuvakova, M. A. [Institute of Natural Sciences, Ural Federal University, 620000 Ekaterinburg (Russian Federation); Tronche, H.; Doutre, F.; Baldi, P.; De Micheli, M. P. [Laboratoire de Physique de la Matière Condensée, University of Nice-Sophia Antipolis, 06100 Nice (France)

    2016-05-09

    Formation of domain structure by electron beam irradiation in congruent lithium niobate covered by surface dielectric layer with planar and channel waveguides produced by Soft Proton Exchange (SPE) process has been studied. Formation of domains with arbitrary shapes as a result of discrete switching has been revealed. The fact was attributed to ineffective screening of depolarization field in the crystals with a surface layer modified by SPE process. The dependences of the domain sizes on the dose and the distance between irradiated areas have been revealed. Finally, we have demonstrated that electron beam irradiation of lithium niobate crystals with surface resist layer can produce high quality periodical domain patterns after channel waveguide fabrication. Second harmonic generation with normalized nonlinear conversion efficiency up to 48%/(W cm{sup 2}) has been achieved in such waveguides.

  20. Fast path and polarization manipulation of telecom wavelength single photons in lithium niobate waveguide devices.

    Science.gov (United States)

    Bonneau, Damien; Lobino, Mirko; Jiang, Pisu; Natarajan, Chandra M; Tanner, Michael G; Hadfield, Robert H; Dorenbos, Sanders N; Zwiller, Val; Thompson, Mark G; O'Brien, Jeremy L

    2012-02-03

    We demonstrate fast polarization and path control of photons at 1550 nm in lithium niobate waveguide devices using the electro-optic effect. We show heralded single photon state engineering, quantum interference, fast state preparation of two entangled photons, and feedback control of quantum interference. These results point the way to a single platform that will enable the integration of nonlinear single photon sources and fast reconfigurable circuits for future photonic quantum information science and technology.

  1. Tunable optical wavelength conversion of OFDM signal using a periodically-poled lithium niobate waveguide.

    Science.gov (United States)

    Wu, Xiaoxia; Peng, Wei-Ren; Arbab, Vahid; Wang, Jian; Willner, Alan

    2009-05-25

    We experimentally demonstrate tunable optical wavelength conversion of a 10-Gb/s radio frequency (RF)-tone assisted orthogonal-frequency-division-multiplexing (OFDM) signal with approximately-5 dB (approximately 30%) efficiency over approximately 30 nm bandwidth using a periodically-poled lithium-niobate (PPLN) waveguide. A penalty of < 3 dB is obtained after wavelength conversion. Quadrature amplitude modulation (QAM) size and subcarrier number are varied to further evaluate the performance of the wavelength converter.

  2. Design of pseudorandom binary sequence generator using lithium-niobate-based Mach-Zehnder interferometers

    Science.gov (United States)

    Choudhary, Kuldeep; Kumar, Santosh

    2017-05-01

    The application of electro-optic effect in lithium-niobate-based Mach-Zehnder interferometer to design a 3-bit optical pseudorandom binary sequence (PRBS) generator has been proposed, which is characterized by its simplicity of generation and stability. The proposed device is optoelectronic in nature. The PBRS generator is immensely applicable for pattern generation, encryption, and coding applications in optical networks. The study is carried out by simulating the proposed device with beam propagation method.

  3. Photoconductive properties of organic-inorganic hybrid films of layered perovskite-type niobate.

    Science.gov (United States)

    Saruwatari, Kazuko; Sato, Hisako; Idei, Tomochika; Kameda, Jun; Yamagishi, Akihiko; Takagaki, Atsushi; Domen, Kazunari

    2005-06-30

    A hybrid film of layered niobate and an organic amphiphile was prepared by the Langmuir-Blodgett (LB) method. Trimethylammonium-exchanged perovskite-type niobates ((CH(3))(3)NHSr(2)Nb(3)O(10)) were exfoliative to form an aqueous suspension. A monolayer of octadecylamine was produced on such an aqueous dispersion as a template for a hybrid film. A hybrid film was transferred as a Y-type LB film onto a hydrophilic glass plate or an ITO substrate. The structure of a deposited film was investigated with X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and atomic force microscopy (AFM) measurements, indicating a layer-by-layer structure with a single or double sheet of niobate as an inorganic composite. From the cyclic voltammogram on an ITO electrode modified with the Y-type 10 layered film, the lower edge of the conduction band of a niobate layer was determined to be - 0.6 V (vs Ag/AgCl). ac impedance and dc measurements were carried out on 1, 5, and 10-layered LB films (2 mm (electrode spacing) x 8 mm (width)) with aluminum electrodes. The freshly deposited samples behaved as an insulator under the illumination of 280 nm light (2.04 x 10(16) quanta s(-1)). Photoconductivities appeared, however, when they were preirradiated with a 150 W Xe lamp (ca. 2 x 10(18) quanta s(-1)) for 0.5-8.5 h. The process was denoted as photomodification. From the FT-IR and XRD results, it was deduced that the photomodification of LB films caused the decomposition of organic templates (octadecylammonium) accompanied by the collapse of layer-by-layer structures. dc analyses on the 5- and 10-layered films after photomodification also showed that they behaved as a photosemiconductor under UV light illumination.

  4. Charge transfer stabilization of late transition metal oxide nanoparticles on a layered niobate support

    OpenAIRE

    Strayer, Megan E.; Senftle, Thomas P.; Winterstein, Jonathan P.; Vargas-Barbosa, Nella M.; Sharma, Renu; Rioux, Robert M.; Janik, Michael J.; Mallouk, Thomas E.

    2015-01-01

    The interfacial interactions between late transition metal/metal oxide nanoparticles and oxide supports impact catalysts��� activity and stability. Here, we report the use of isothermal titration calorimetry (ITC), electron microscopy and density functional theory (DFT) to explore periodic trends in the heats of nanoparticle-support interactions for late transition metal and metal oxide nanoparticles on layered niobate and silicate supports. Data for Co(OH)2, hydroxyiridate-capped IrOx.nH2O, ...

  5. Fabrication of lithium niobate for three wave mixing, quantum information and communications

    Science.gov (United States)

    Mircovich, Matthew

    Lithium Niobate (LN) is a crystal that has applications in nonlinear optics. Poling LN crystals allows quasi phase matching and three wave mixing to be achieved while allowing crystals to be longer without incurring a phase-mismatch penalty. Periodically Poled Lithium Niobate (PPLN) has a high degree of effective nonlinearity due to the increased interaction length. Fabrication of PPLN crystals starts from a Lithium Niobate wafer doped with MgO. The wafer is periodically patterned with photoresist, then placed inside a conductive electrolyte solution. A high voltage is applied through the solution, contacting the wafer where the resist is absent. A 3-5 kV pulse is applied through the electrolyte, causing a domain reversal between the photoresist, leading to periodic poling. An alternative fabrication process of PPLN involves the wafer periodically patterned with electrodes and placed in a dielectric oil bath held at a constant temperature. The fabrication of PPLN will be explored using various voltages, temperatures and periods. The fabricated structures will be tested in frequency upconversion and downconversion experiments for quantum information and communication applications.

  6. Tailoring ferromagnetism in chromium-doped zinc oxide

    KAUST Repository

    Haq, Bakhtiar Ul

    2014-03-11

    The simultaneous manipulation of both charge and spin has made diluted magnetic semiconductors (DMS) a potential material for the fabrication of spintronic devices. We report DMSs based on ZnO doped with Cr in wurtzite (WZ) and zinc-blend (ZB) geometries. The injection of Cr impurities at a concentration of 6.25% has successfully tuned ferromagnetism in ZnO. To recognize the nature of magnetic interactions, two spatial configurations are investigated, where the impurity atoms are placed at minimum and maximum separation distances. The material favors the short-range magnetic coupling and has a tendency towards Cr clustering. The injection of a Cr impurity into ZnO strongly influences the electronic properties in terms of band structure, dependent on the impurity spatial distribution. It is half metallic for both structural geometries when impurity atoms have minimum separation and is metallic when they are placed far apart. Moreover, replacing Zn with Cr does not show a significant effect on the structural geometries. Our results endorse that Cr:ZnO can be efficiently used for spin-polarized transport and other spin-dependent applications in both hexagonal and cubic phases.

  7. Tetravalent chromium doped laser materials and NIR tunable lasers

    Science.gov (United States)

    Alfano, Robert R. (Inventor); Petricevic, Vladimir (Inventor); Bykov, Alexey (Inventor)

    2008-01-01

    A method is described to improve and produce purer Cr.sup.4+-doped laser materials and lasers with reduced co-incorporation of chromium in any other valence states, such as Cr.sup.3+, Cr.sup.2+, Cr.sup.5+, and Cr.sup.6+. The method includes: 1) certain crystals of olivine structure with large cation (Ca) in octahedral sites such as Cr.sup.4+:Ca.sub.2GeO.sub.4, Cr.sup.4+:Ca.sub.2SiO.sub.4, Cr.sup.4+:Ca.sub.2Ge.sub.xSi.sub.1-xO.sub.4 (where 0

  8. Optical emission spectra of chromium doped nanocrystalline zinc gallate

    Science.gov (United States)

    Dhak, P.; Gayen, U. K.; Mishra, S.; Pramanik, P.; Roy, A.

    2009-09-01

    Optical emission spectra of nanocrystalline zinc gallate (ZnGa2O4) and trivalent chromium ion doped zinc gallate (ZnGa2O4:Cr3+) are reported for different concentrations of the dopant ion. The measurements have been carried out over the temperature range between 77 and 296 K. The emission spectrum of nanocrystalline ZnGa2O4 shows two broad peaks. The intensity variation in these peaks, with temperature, is indicative of the effect of symmetry breaking in the electronic band structure of ZnGa2O4 in nanocrystalline samples. In addition, we find that the relative intensities of the sharp spectral lines of Cr3+ in nanocrystalline ZnGa2O4:Cr3+ are quite different from those reported for corresponding bulk samples. The spectral profiles of the so-called R1, R2, N1, and N2 lines have also been studied. The data are analyzed using crystal field theory, which includes an exchange interaction between the nearest neighbor Cr3+ pairs in ZnGa2O4. We estimate the exchange parameters for Cr3+ in nanocrystalline ZnGa2O4:Cr3+. Though, in the literature, there exist reports on optical properties of the corresponding bulk spinel, our approach and consequent results on nanocrystalline ZnGa2O4:Cr3+ are not only interesting from the physics point of view but also can be of use in nanotechnology.

  9. Versatile Chromium-Doped Zinc Selenide Infrared Laser Sources

    Science.gov (United States)

    2010-05-01

    short time periods, allow for frequency modulation or multiplexing or select specific absorption features. The end result of all of the above is a...to the high thermo-optic coefficients, compared to other materials in Table 2, of ZnS (46 x 10-6 1/K), ZnSe (70 x 10-6 1/K), CdSe and CdTe (both...defect or from non-radiative losses [2]. Table 2: Material properties of various laser host materials[46] Property ZnSe ZnS CdSe CdTe Sapphire

  10. FEATURES OF CHROMIUM DOPING OF WEAR-RESISTANT CAST IRON

    Directory of Open Access Journals (Sweden)

    V. V. Netrebko

    2013-01-01

    Full Text Available The aim of this work analysis of the influence of chromium on the process of carbide formation, changes in chemical composition of the metal substrate in the areas adjacent to the carbides and at the hardness of iron while economy nickel and manganesealloying.

  11. Structural and magnetic properties of chromium-doped ferrite nanopowders

    Energy Technology Data Exchange (ETDEWEB)

    Costa, A.C.F.M., E-mail: anacristina@dema.ufcg.edu.b [Department of Materials Engineering, Federal University of Campina Grande, Av. Aprigio Veloso - 882, Bodocongo, 58429-140 Campina Grande, PB (Brazil); Silva, V.J.; Ferreira, H.S. [Department of Materials Engineering, Federal University of Campina Grande, Av. Aprigio Veloso - 882, Bodocongo, 58429-140 Campina Grande, PB (Brazil); Costa, A.A. [Department of Physics, Federal University of Pernambuco, 50670-901 Recife, PE (Brazil); Cornejo, D.R. [Institute of Physics, Sao Paulo University, 05508-900 Sao Paulo, SP (Brazil); Kiminami, R.H.G.A. [Federal University of Sao Carlos, Department of Materials Engineering, 13565-905 Sao Carlos, SP (Brazil); Gama, L. [Department of Materials Engineering, Federal University of Campina Grande, Av. Aprigio Veloso - 882, Bodocongo, 58429-140 Campina Grande, PB (Brazil)

    2009-08-26

    This paper reports on a study of Cr{sup 3+}-doped nanosized Ni-Zn ferrites produced by combustion reaction, and evaluates their morphological and magnetic properties. The powders were characterized by X-ray diffraction (XRD) and SEM and magnetic properties. All the compositions showed the formation of the inverse spinel phase of Ni-Zn ferrite. The average crystallite size ranged from 21 to 26 nm. The saturation magnetization was found to be in the range of 53-43 emu/g. The increase in Cr{sup 3+} concentration in the Ni-Zn ferrite caused a reduction in hysteresis losses and a slight reduction in the saturation magnetization.

  12. Genetic disorders of potassium homeostasis.

    Science.gov (United States)

    Jain, Gaurav; Ong, Song; Warnock, David G

    2013-05-01

    Hereditary disorders of potassium homeostasis are an interesting group of disorders, affecting people from the newborn period to adults of all ages. The clinical presentation varies from severe hypotension at birth to uncontrolled hypertension in adults, often associated with abnormal potassium values, although many patients may have a normal serum potassium concentration despite being affected by the genetic disorder. A basic understanding of these disorders and their underlying mechanisms has significant clinical implications, especially in the few patients with subtle clinical signs and symptoms. We present a summary of these disorders, with emphasis on the clinical presentation and genetic mechanisms of these disorders. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Potassium 4-azidobenzenesulfonate

    Directory of Open Access Journals (Sweden)

    Frank Biesemeier

    2014-08-01

    Full Text Available In, K+·SO3–p-C6H4–N3−, the conformation angle of the azido group with respect to the benzene ring is 19.1 (3°, so that the anion is chiral within the crystal structure. In addition, the crystal structure is also chiral (Sohncke space group. The potassium ion is coordinated by three closer O atoms from three different sulfonyl groups [K...O 2.6486 (17 to 2.7787 (17 Å], three more distant O atoms [K...O 2.959 (2 to 3.206 (2 Å] and three N atoms at 3.073 (2 to 3.268 (2 Å. The anions are packed into layers perpendicular to b, only O and N atoms being at the surface of the layers. The K+ ions are located between the layers.

  14. Potassium Channels in Neurofbromatosis-1

    National Research Council Canada - National Science Library

    Chen, Mingkui

    2006-01-01

    .... We were the first to investigate potential mechanisms of cognitive impairment in NF-1 at the molecular level involving potassium channels, and demonstrated a possible mechanism for the learning deficits seen in NF1...

  15. 21 CFR 184.1610 - Potassium alginate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium alginate. 184.1610 Section 184.1610 Food... Specific Substances Affirmed as GRAS § 184.1610 Potassium alginate. (a) Potassium alginate (CAS Reg. No... algae. Potassium alginate is prepared by the neutralization of purified alginic acid with appropriate pH...

  16. The combination methodic of diffusion and implantation technologies for creating optic wave-guided layers in lithium niobate

    Science.gov (United States)

    Orlikov, L. N.; Orlikov, N. L.; Arestov, S. I.; Mambetova, K. M.; Shandarov, S. M.

    2015-04-01

    The implantation of copper into Lithium Niobate in the prohibited crystal zone forms a definite energetic level for optic transits. This paper examines conditions of optic wave-guided layers formation on Niobate Lithium due to the method of implantation copper ions with the next diffusion. Reflect Spectrum in consequences implantation is extended. The transfer of the optical power from the primary beam into the another beam was discovered and in reverse. Photo galvanic characteristics of implantation specimen identity of crystal by traditional technology and doping CuO manufacture.

  17. Charge Transfer Stabilization of Late Transition Metal Oxide Nanoparticles on a Layered Niobate Support.

    Science.gov (United States)

    Strayer, Megan E; Senftle, Thomas P; Winterstein, Jonathan P; Vargas-Barbosa, Nella M; Sharma, Renu; Rioux, Robert M; Janik, Michael J; Mallouk, Thomas E

    2015-12-30

    Interfacial interactions between late transition metal/metal oxide nanoparticles and oxide supports impact catalytic activity and stability. Here, we report the use of isothermal titration calorimetry (ITC), electron microscopy and density functional theory (DFT) to explore periodic trends in the heats of nanoparticle-support interactions for late transition metal and metal oxide nanoparticles on layered niobate and silicate supports. Data for Co(OH)2, hydroxyiridate-capped IrOx·nH2O, Ni(OH)2, CuO, and Ag2O nanoparticles were added to previously reported data for Rh(OH)3 grown on nanosheets of TBA0.24H0.76Ca2Nb3O10 and a layered silicate. ITC measurements showed stronger bonding energies in the order Ag niobate support, as expected from trends in M-O bond energies. Nanoparticles with exothermic heats of interaction were stabilized against sintering. In contrast, ITC measurements showed endothermic interactions of Cu, Ni, and Rh oxide/hydroxide nanoparticles with the silicate and poor resistance to sintering. These trends in interfacial energies were corroborated by DFT calculations using single-atom and four-atom cluster models of metal/metal oxide nanoparticles. Density of states and charge density difference calculations reveal that strongly bonded metals (Rh, Ir) transfer d-electron density from the adsorbed cluster to niobium atoms in the support; this mixing is absent in weakly binding metals, such as Ag and Au, and in all metals on the layered silicate support. The large differences between the behavior of nanoparticles on niobate and silicate supports highlight the importance of d-orbital interactions between the nanoparticle and support in controlling the nanoparticles' stability.

  18. Aperture scaling effects with monolithic periodically poled lithium niobate optical parametric oscillators and generators.

    Science.gov (United States)

    Missey, M; Dominic, V; Powers, P; Schepler, K L

    2000-02-15

    We used elliptical beams to demonstrate aperture scaling effects in nanosecond single-grating and multigrating periodically poled lithium niobate (PPLN) monolithic optical parametric oscillators and generators. Increasing the cavity Fresnel number in single-grating crystals broadened both the beam divergence and the spectral bandwidth. Both effects are explained in terms of the phase-matching geometry. These effects are suppressed when a multigrating PPLN crystal is used because the individual gratings provide small effective subapertures. A flood-pumped multigrating optical parametric generator displayed a low output beam divergence and contained 19 pairs of signal and idler frequencies.

  19. Evaluation of the internal field in lithium niobate ferroelectric domains by an interferometric method

    Science.gov (United States)

    de Angelis, M.; De Nicola, S.; Finizio, A.; Pierattini, G.; Ferraro, P.; Grilli, S.; Paturzo, M.

    2004-10-01

    We report on the evaluation of internal electric field of a ferroelectric engineered-domain in a LiNbO3 wafer crystal by detecting optical path length variation with a noninvasive interferometric inspection method. The lithium niobate wafer has been patterned and subjected to electric field poling to obtain two antiparallel ferroelectric domains separated by a single domain wall. The crystal has been mounted into one arm of a Mach-Zehnder-type interferometer to study the phase map and evaluate the effects of domain reversion by a digital holographic technique. Evaluation of the internal field and consequent variation of the electro-optical properties of the different domains is analyzed.

  20. Narrowband terahertz generation with chirped-and-delayed laser pulses in periodically poled lithium niobate.

    Science.gov (United States)

    Ahr, Frederike; Jolly, Spencer W; Matlis, Nicholas H; Carbajo, Sergio; Kroh, Tobias; Ravi, Koustuban; Schimpf, Damian N; Schulte, Jan; Ishizuki, Hideki; Taira, Takunori; Maier, Andreas R; Kärtner, Franz X

    2017-06-01

    We generate narrowband terahertz (THz) radiation in periodically poled lithium niobate (PPLN) crystals using two chirped-and-delayed driver pulses from a high-energy Ti:sapphire laser. The generated frequency is determined by the phase-matching condition in the PPLN and influences the temporal delay of the two pulses for efficient terahertz generation. We achieve internal conversion efficiencies up to 0.13% as well as a record multicycle THz energy of 40 μJ at 0.544 THz in a cryogenically cooled PPLN.

  1. Chirality control by electric field in periodically poled MgO-doped lithium niobate

    OpenAIRE

    Shi, Lei; Tian, Linghao; Chen, Xianfeng

    2012-01-01

    We study the chirality of periodically poled MgO-doped lithium niobate (MgO:PPLN) by electro-optic (EO) effect. It shows that optical propagation is reciprocal in MgO:PPLN when quasi-phase-matching (QPM) condition is satisfied, which is similar to natural optical active material like quartz. The specific rotation of MgO:PPLN by EO effect is shown to be proportional to the transverse electric field, making large polarization rotation in optical active material with small size possible. We also...

  2. Short-length and robust polarization rotators in periodically poled lithium niobate via shortcuts to adiabaticity.

    Science.gov (United States)

    Chen, Xi; Wang, Hong-Wei; Ban, Yue; Tseng, Shuo-Yen

    2014-10-06

    Conventional narrowband spectrum polarization devices are short but not robust, based on quasi-phase matching (QPM) technique, in periodically poled lithium niobate (PPLN) crystal. In this paper, we propose short-length and robust polarization rotators by using shortcuts to adiabaticity. Beyond the QPM condition, the electric field and period of PPLN crystal are designed in terms of invariant dynamics, and further optimized with respect to input wavelength/refractive index variations. In addition, the stability of conversion efficiency on the electric field and period of PPLN crystal is also discussed. As a consequence, the optimal shortcuts are fast as well as robust, which provide broadband spectrum polarization devices with short length.

  3. Ultrashort pulse chirp measurement via transverse second-harmonic generation in strontium barium niobate crystal

    Energy Technology Data Exchange (ETDEWEB)

    Trull, J.; Wang, B.; Parra, A.; Vilaseca, R.; Cojocaru, C. [Departament de Física i Enginyeria Nuclear, Universitat Politècnica Catalunya, Terrassa 08222 (Spain); Sola, I. [Grupo de Investigación en Óptica Extrema (GIOE), Departamento de Física Aplicada, Universidad de Salamanca, Plaza de la Merced s/n, 37008 Salamanca (Spain); Krolikowski, W. [Laser Physics Centre, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia); Science Program, Texas A and M University at Qatar, Doha (Qatar); Sheng, Y. [Laser Physics Centre, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia)

    2015-06-01

    Pulse compression in dispersive strontium barium niobate crystal with a random size and distribution of the anti-parallel orientated nonlinear domains is observed via transverse second harmonic generation. The dependence of the transverse width of the second harmonic trace along the propagation direction allows for the determination of the initial chirp and duration of pulses in the femtosecond regime. This technique permits a real-time analysis of the pulse evolution and facilitates fast in-situ correction of pulse chirp acquired in the propagation through an optical system.

  4. Design of optical seven-segment decoder using Pockel's effect inside lithium niobate-based waveguide

    Science.gov (United States)

    Pal, Amrindra; Kumar, Santosh; Sharma, Sandeep

    2017-01-01

    Seven-segment decoder is a device that allows placing digital information from many inputs to many outputs optically, having 11 Mach-Zehnder interferometers (MZIs) for their implementation. The layout of the circuit is implemented to fit the electrical method on an optical logic circuit based on the beam propagation method (BPM). Seven-segment decoder is proposed using electro-optic effect inside lithium niobate-based MZIs. MZI structures are able to switch an optical signal to a desired output port. It consists of a mathematical explanation about the proposed device. The BPM is also used to analyze the study.

  5. Investigation of the cluster formation in lithium niobate crystals by computer modeling method

    Energy Technology Data Exchange (ETDEWEB)

    Voskresenskii, V. M.; Starodub, O. R., E-mail: ol-star@mail.ru; Sidorov, N. V.; Palatnikov, M. N. [Russian Academy of Sciences, Tananaev Institute of Chemistry and Technology of Rare Earth Elements and Mineral Raw Materials, Kola Science Centre (Russian Federation)

    2017-03-15

    The processes occurring upon the formation of energetically equilibrium oxygen-octahedral clusters in the ferroelectric phase of a stoichiometric lithium niobate (LiNbO{sub 3}) crystal have been investigated by the computer modeling method within the semiclassical atomistic model. An energetically favorable cluster size (at which a structure similar to that of a congruent crystal is organized) is shown to exist. A stoichiometric cluster cannot exist because of the electroneutrality loss. The most energetically favorable cluster is that with a Li/Nb ratio of about 0.945, a value close to the lithium-to-niobium ratio for a congruent crystal.

  6. Laser scattering induced holograms in lithium niobate. [observation of diffraction cones

    Science.gov (United States)

    Magnusson, R.; Gaylord, T. K.

    1974-01-01

    A 3.0-mm thick poled single crystal of lithium niobate doped with 0.1 mole% iron was exposed to a single beam and then to two intersecting beams of an argon ion laser operating at 515-nm wavelength. Laser scattering induced holograms were thus written and analyzed. The presence of diffraction cones was observed and is shown to result from the internally recorded interference pattern resulting from the interference of the original incident laser beam with light scattered from material inhomogeneities. This phenomenon is analyzed using Ewald sphere construction techniques which reveal the geometrical relationships existing for the diffraction cones.

  7. Fabrication of Pattern Poled Lithium Niobate Film and its Nonlinear Optical Applications

    Science.gov (United States)

    Xu, M.; Wang, M.; Chen, Z.; Tang, J.; Shao, G.; Ming, Y.; Cui, G.; Lu, Y.

    2017-06-01

    We develop an approach to fabricate arbitrary ferroelectric domain patterns on lithium niobate film (30-50 μm thick) by applying a structured external field at room temperature. The fabricating method can be operated easily to reach 1 μm linewidth resolution. The ferroelectric domain inversion is stable and uniform. Nonlinear diffraction is generated when the fundamental wave pumps to film. Various nonlinear wavefronts are obtained such as the frequency converted optical vortex beam. A nonlinear holographic concept is proposed to explain the physical phenomena and guide the corresponding domain design. The applications in optical field manipulation and novel photonic states generation are discussed.

  8. Domain-Reversed Lithium Niobate Single-Crystal Fibers are Potentially for Efficient Terahertz Wave Generation

    Directory of Open Access Journals (Sweden)

    Yalin Lu

    2008-01-01

    Full Text Available Nonlinear frequency conversion remains one of the dominant approaches to efficiently generate THz waves. Significant material absorption in the THz range is the main factor impeding the progress towards this direction. In this research, a new multicladding nonlinear fiber design was proposed to solve this problem, and as the major experimental effort, periodic domain structure was introduced into lithium niobate single-crystal fibers by electrical poling. The introduced periodic domain structures were nondestructively revealed using a crossly polarized optical microscope and a confocal scanning optical microscope for quality assurance.

  9. Bidomain structures formed in lithium niobate and lithium tantalate single crystals by light annealing

    Science.gov (United States)

    Kubasov, I. V.; Kislyuk, A. M.; Bykov, A. S.; Malinkovich, M. D.; Zhukov, R. N.; Kiselev, D. A.; Ksenich, S. V.; Temirov, A. A.; Timushkin, N. G.; Parkhomenko, Yu. N.

    2016-03-01

    The bidomain structures produced by light external heating in z-cut lithium niobate and lithium tantalate single crystals are formed and studied. Interdomain regions about 200 and 40 μm wide in, respectively, LiNbO3 and LiTaO3 bidomain crystals are visualized and studied by optical microscopy and piezoresponse force microscopy. Extended chains and lines of domains in the form of thin layers with a width less than 10 μm in volume, which penetrate the interdomain region and spread over distances of up to 1 mm, are found.

  10. Optical Formation of Waveguide Elements in Photorefractive Surface Layer of a Lithium Niobate Sample

    Science.gov (United States)

    Bezpaly, A. D.; Shandarov, V. M.

    Formation of channel optical waveguides due to the sequential point-to-point exposure of local stripe-like regions of Y-cut lithium niobate sample surface is experimentally investigated. The surface layer of the sample is thermally doped with Cu ions to increase its photorefractive sensitivity. The laser radiation with wavelength of 532 nm and optical power of 10 mW is used for the crystal exposure in experiments. The optical inhomogeneities formed during the sample exposure are studied with their probing by laser beams with wavelength of 633 nm.

  11. Structural, topographical and electrical properties of cerium doped strontium barium niobate (Ce:SBN60) ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Raj, S. Gokul [Department of Physics, C. Kandaswami Naidu College For Men (CKNC), Annanagar, Chennai-600102 (India); Mathivanan, V.; Mohan, R. [Department of Physics, Presidency College, Chennai – 600005 (India); Kumar, G. Ramesh, E-mail: rameshvandhai@gmail.com; Yathavan, S. [Department of Physics, University College of Engineering Arni, Anna University Chennai, Arni-632317 (India)

    2016-05-06

    Tungsten bronze type cerium doped strontium barium niobate (Ce:SBN - Sr{sub 0.6}B{sub 0.4}Nb{sub 2}O{sub 6}) ceramics were synthesized by solid state process. Cerium was used as dopant to improve its electrical properties. Influence of Ce{sup +} ions on the photoluminescence properties was investigated in detail. The grain size topographical behavior of SBN powders and their associated abnormal grain growth (AGG) were completely analyzed through SEM studies. Finally dielectric, measurement discusses about the broad phase transition observed due to cerium dopant The results were discussed in detail.

  12. Nanoparticles in the zirconia-europium niobate system via hydrothermal route.

    Science.gov (United States)

    Hirano, Masanori; Dozono, Hayato

    2013-10-01

    The effect of the composition on the hydrothermal formation, structure, and properties of nanocrystalline luminescent materials in the zirconia (ZrO2)-europium niobate 1/4(Eu3NbO7) system was investigated. In the composition range 40 particles with crystallite size 6.0-7.6 nm that were hydrothermally formed from the precursor solutions of NbCl5, ZrOCI2, and EuCl3 under weakly basic conditions at 240 degrees C showed cubic structure. The lattice parameter when estimated as a single cubic phase linearly decreased as the concentration of ZrO2 increased. The presence of zirconia component effectively promoted the formation of nanocrystals containing the niobate, Eu3NbO7 under hydrothermal condition. The nanocrystalline particles could be excited by ultraviolet light 395 nm (f-f transition) and emitted orange (590 nm) and red light (610 nm) corresponding to 5D0 --> 7F1 and 5D0 --> 7F2 transitions of Eu3+, respectively. The intensity of the electric dipole transition (5D0 --> 7F2) that was expressed in values relative to the magnetic dipole transition (5D0 --> 7F1) increased with increased heat-treatment temperature in the range from 950 to 1200 degrees C.

  13. Solid sampling determination of magnesium in lithium niobate crystals by graphite furnace atomic absorption spectrometry

    Science.gov (United States)

    Dravecz, Gabriella; Laczai, Nikoletta; Hajdara, Ivett; Bencs, László

    2016-12-01

    The vaporization/atomization processes of Mg in high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS-GFAAS) were investigated by evaporating solid (powder) samples of lithium niobate (LiNbO3) optical single crystals doped with various amounts of Mg in a transversally heated graphite atomizer (THGA). Optimal analytical conditions were attained by using the Mg I 215.4353 nm secondary spectral line. An optimal pyrolysis temperature of 1500 °C was found for Mg, while the compromise atomization temperature in THGAs (2400 °C) was applied for analyte vaporization. The calibration was performed against solid (powered) lithium niobate crystal standards. The standards were prepared with exactly known Mg content via solid state fusion of the oxide components of the matrix and analyte. The correlation coefficient (R value) of the linear calibration was not worse than 0.9992. The calibration curves were linear in the dopant concentration range of interest (0.74-7.25 mg/g Mg), when dosing 3-10 mg of the powder samples into the graphite sample insertion boats. The Mg content of the studied 19 samples was in the range of 1.69-4.13 mg/g. The precision of the method was better than 6.3%. The accuracy of the results was verified by means of flame atomic absorption spectrometry with solution sample introduction after digestion of several crystal samples.

  14. Ferroelectric and structural characterization of alkali niobate piezoceramics derived from a citrate liquid precursor

    Energy Technology Data Exchange (ETDEWEB)

    Kakimoto, Kenichi; Nguyen, Lien Thikim; Hayakawa, Yusuke; Shinkai, Yuya; Kagomiya, Isao [Nagoya Institute of Technology, Nagoya (Japan)

    2011-09-15

    Preparation of alkali-niobate ceramic powders of KNbO{sub 3}, (Na,K)NbO{sub 3}, and (Li,Na,K)NbO{sub 3} has been carried out by using a citrate-based liquid precursor route that was a newly developed innovative wet powder processing technique. The derived powders showed a well-sinterable property, and the sintered ceramics demonstrated excellent ferroelectric property. Orthorhombic KNbO{sub 3} showed a remanent polarization (P{sub r}) of 23.3 {mu}C/cm{sup 2} and a coercive field (E{sub c}) of 7.8 kV/cm, and (Na,K)NbO{sub 3} showed a Pr of 31.4 {mu}C/cm{sup 2} and a E{sub c} of 17.3 kV/cm. On the other hand, tetragonal (Li,Na,K)NbO{sub 3} demonstrated a Pr of 19.0 {mu}C/cm{sup 2} and a E{sub c} of 13.6 kV/cm. The citrate liquid precursor route demonstrated a good potential for the synthesis of fine powders suitable for lead-free alkali-niobate ceramics.

  15. Temperature sensing in E.M.D. environment with periodically poled lithium niobate devices

    Science.gov (United States)

    Margheri, G.; Del Rosso, T.; Trigari, S.; Sottini, S.; Grando, D.; D'Orazio, A.; De Sario, M.; Petruzzelli, V.; Prudenzano, F.

    2006-04-01

    A temperature sensor immune to electromagnetic noise is designed and fabricated. The sensor key element is a periodically poled lithium niobate (PPLN) substrate. PPLN allows a direct and efficient frequency conversion of lightwave through the quasi-phase matching (QPM) of the pump radiation propagating at the fundamental and second harmonic wavelengths. For these devices, the efficiency of second harmonic generation (SHG) depends on the QPM condition, and it strongly changes with respect to the wavelength and the temperature. The effect of temperature variation on the SHG in periodically poled lithium niobate annealed proton exchange (APE) channel waveguides (WG) is theoretically modeled via a home-made computer code and experimentally validated via a suitable measurement set-up. A lot of simulations have been performed to test the temperature sensor feasibility and to identify its optimal configuration. Another sensor configuration made by two waveguides with suitable gratings of inverted ferroelectric domains is designed and refined, too. For an optimised PPLN-WG device, which could be fabricated through electric field poling and annealed proton exchange or titanium diffusion, a sensitivity S≡0.03μW/°C for the temperature range equal to 100 °C is demonstrated by using an input power at a fundamental wavelength equal to 40 mW. Similar evaluations and measurements, performed on bulk substrates, allowed us to design a layout of a sensor particularly suited for rugged in-field applications.

  16. Porous calcium niobate nanosheets prepared by an exfoliation-restacking route.

    Science.gov (United States)

    Hashemzadeh, Fatemeh

    2016-01-01

    The single phase layered perovskite-type niobate KCa2Nb3O10 was obtained by a solid state reaction of the starting materials (K2CO3, CaCO3 and Nb2O5) at 1,200 °C. Then the H(+)-exchanged form (HCa2Nb3O10) was successfully exfoliated into colloidal porous single layers on the intercalating action of tetra(butyl)ammonium ion. The various characterization techniques such as X-ray diffraction (XRD), field-emission scanning electron microscopy, N2 absorption-desorption and diffuse reflectance UV-visible spectrometry gave important information on the unusual structural features of the perovskite-related niobate nanosheets. XRD analysis of the exfoliated nanosheets showed a unique profile with wide peaks that represented individual molecular aspects of the nanosheets. The Brunauer-Emmett-Teller isotherm of the exfoliated coiled nanosheets showed a sharp increase in the surface area by a factor of >30 in comparison to parent layered material, which is due to the exfoliation and restacking process. The nanosheets in this study were also found to act as a semiconductor with a wide band gap that is due to the quantum size effect.

  17. Periodic domain inversion in x-cut single-crystal lithium niobate thin film

    Science.gov (United States)

    Mackwitz, P.; Rüsing, M.; Berth, G.; Widhalm, A.; Müller, K.; Zrenner, A.

    2016-04-01

    We report the fabrication of periodically poled domain patterns in x-cut lithium niobate thin-film. Here, thin films on insulator have drawn particular attention due to their intrinsic waveguiding properties offering high mode confinement and smaller devices compared to in-diffused waveguides in bulk material. In contrast to z-cut thin film lithium niobate, the x-cut geometry does not require back electrodes for poling. Further, the x-cut geometry grants direct access to the largest nonlinear and electro-optical tensor element, which overall promises smaller devices. The domain inversion was realized via electric field poling utilizing deposited aluminum top electrodes on a stack of LN thin film/SiO2 layer/Bulk LN, which were patterned by optical lithography. The periodic domain inversion was verified by non-invasive confocal second harmonic microscopy. Our results show domain patterns in accordance to the electrode mask layout. The second harmonic signatures can be interpreted in terms of spatially, overlapping domain filaments which start their growth on the +z side.

  18. Surface acoustic waves in acoustic superlattice lithium niobate coated with a waveguide layer

    Science.gov (United States)

    Yang, G. Y.; Du, J. K.; Huang, B.; Jin, Y. A.; Xu, M. H.

    2017-04-01

    The effects of the waveguide layer on the band structure of Rayleigh waves are studied in this work based on a one-dimensional acoustic superlattice lithium niobate substrate coated with a waveguide layer. The present phononic structure is formed by the periodic domain-inverted single crystal that is the Z-cut lithium niobate substrate with a waveguide layer on the upper surface. The plane wave expansion method (PWE) is adopted to determine the band gap behavior of the phononic structure and validated by the finite element method (FEM). The FEM is also used to investigate the transmission of Rayleigh waves in the phononic structure with the interdigital transducers by means of the commercial package COMSOL. The results show that, although there is a homogeneous waveguide layer on the surface, the band gap of Rayleigh waves still exist. It is also found that increasing the thickness of the waveguide layer, the band width narrows and the band structure shifts to lower frequency. The present approach can be taken as an efficient tool in designing of phononic structures with waveguide layer.

  19. Immobilization of hemoglobin at the galleries of layered niobate HCa2Nb3O10.

    Science.gov (United States)

    Gao, Lu; Gao, Qiuming; Wang, Qigang; Peng, Shuge; Shi, Jianlin

    2005-09-01

    Hemoglobin (Hb) was intercalated at the galleries of layered niobate HCa(2)Nb(3)O(10) (HCNO). Two different kinds of layered phases of Hb-CNO composites Hb-CNO-1 and Hb-CNO-2 were obtained with the interlayer distances of 7.2 and 10.3nm in correspondence with the monolayer and bilayer arrangements of proteins between the niobate layers, respectively, based on the powder XRD pattern, HRTEM, UV-vis spectra and CHN analyses. FTIR spectra of Hb-CNO composites show that amide I and amide II bands were actually the same as those of the native Hb, which indicates that there is almost no structural change after immobilization. Michaelis-Menten model methods were used to study the peroxidatic activity of the reaction of 2-methoxyphenol and H(2)O(2) for the entrapped Hb in the galleries of HCNO. Compared to that of free Hb, the kinetic parameters of Hb-CNO k(cat), K(M) and k(cat)/K(M) were affected by the immobilization process. The immobilized Hb showed a higher relative activity than that of free Hb after incubated in phosphate buffer (pH = 7) at 80 degrees C for a period of time. The environments between the layers of HCNO are hydrophilic which will bind water tightly and help to stabilize the 'essential water' layer around the protein. So, immobilization of Hb between the layers of HCNO enhanced the activity of Hb in water-DMSO mixture.

  20. Elastic band gaps for surface modes in an ultrasonic lithium niobate phononic crystal

    Science.gov (United States)

    Benchabane, S.; Khelif, A.; Robert, L.; Rauch, J. Y.; Pastureaud, T.; Laude, V.

    2006-04-01

    If a number of experiments aiming at demonstrating fundamental properties of phononic crystals have been successfully implemented, a need for enlarging both the research and the application fields of these structures has more recently risen. Surface acoustic waves appear as appealing candidates to set a new ground for illustrative experiments involving some different physical concepts from those usually observed when dealing with bulk waves. The possibility of a direct excitation of these surface waves on a piezoelectric material, and their already extensive use in ultrasonics also make them an interesting basis for phononic crystal based, acoustic signal processing devices. In this work, wave propagation in a square lattice, piezoelectric phononic crystal consisting of air holes etched in a lithium niobate matrix is both theoretically and experimentally investigated. The crystal was fabricated by reactive ion etching of a bulk lithium niobate substrate. Standard interdigital transducers were used to characterize the phononic structure by direct electrical generation and detection of surface waves. A full band gap around 200 MHz was experimentally demonstrated, and close agreement is found with theoretical predictions.

  1. Can Diuretics Decrease Your Potassium Level?

    Science.gov (United States)

    Diseases and Conditions High blood pressure (hypertension) Can diuretics decrease your potassium level? Answers from Sheldon G. Sheps, M.D. Yes, some diuretics — also called water pills — decrease potassium in the ...

  2. Radiation dosimetry by potassium feldspar

    Indian Academy of Sciences (India)

    Unknown

    Radiation dosimetry by potassium feldspar. ARUN PANDYA*, S G VAIJAPURKAR and P K BHATNAGAR. Defence Laboratory, Jodhpur 342 011, India. MS received 12 July 1999; revised 15 February 2000. Abstract. The thermoluminescence (TL) properties of raw and annealed feldspar have been studied for their.

  3. Le niobate de lithium a haute temperature pour les applications ultrasons =

    Science.gov (United States)

    De Castilla, Hector

    L'objectif de ce travail de maitrise en sciences appliquees est de trouver puis etudier un materiau piezoelectrique qui est potentiellement utilisable dans les transducteurs ultrasons a haute temperature. En effet, ces derniers sont actuellement limites a des temperatures de fonctionnement en dessous de 300°C a cause de l'element piezoelectrique qui les compose. Palier a cette limitation permettrait des controles non destructifs par ultrasons a haute temperature. Avec de bonnes proprietes electromecaniques et une temperature de Curie elevee (1200°C), le niobate de lithium (LiNbO 3) est un bon candidat. Mais certaines etudes affirment que des processus chimiques tels que l'apparition de conductivite ionique ou l'emergence d'une nouvelle phase ne permettent pas son utilisation dans les transducteurs ultrasons au-dessus de 600°C. Cependant, d'autres etudes plus recentes ont montre qu'il pouvait generer des ultrasons jusqu'a 1000°C et qu'aucune conductivite n'etait visible. Une hypothese a donc emerge : une conductivite ionique est presente dans le niobate de lithium a haute temperature (>500°C) mais elle n'affecte que faiblement ses proprietes a hautes frequences (>100 kHz). Une caracterisation du niobate de lithium a haute temperature est donc necessaire afin de verifier cette hypothese. Pour cela, la methode par resonance a ete employee. Elle permet une caracterisation de la plupart des coefficients electromecaniques avec une simple spectroscopie d'impedance electrochimique et un modele reliant de facon explicite les proprietes au spectre d'impedance. Il s'agit de trouver les coefficients du modele permettant de superposer au mieux le modele avec les mesures experimentales. Un banc experimental a ete realise permettant de controler la temperature des echantillons et de mesurer leur impedance electrochimique. Malheureusement, les modeles actuellement utilises pour la methode par resonance sont imprecis en presence de couplages entre les modes de vibration. Cela

  4. Ultrafast optical reversible double Feynman logic gate using electro-optic effect in lithium-niobate based Mach Zehnder interferometers

    Science.gov (United States)

    Chauhan, Chanderkanta; Bedi, Amna; Kumar, Santosh

    2017-02-01

    In this ultra fast computing era power optimization is a major technological challenge that requires new computing paradigms. Conservative and reversible logic opens up the possibility of ultralow power computing. In this paper, basic reversible logic gate (double Feynman gate) using the lithium-niobate based Mach-Zehnder interferometer is proposed. The results are verified using beam propagation method and MATLAB simulations.

  5. Increased serum potassium affects renal outcomes

    DEFF Research Database (Denmark)

    Miao, Y; Dobre, D; Heerspink, H J Lambers

    2011-01-01

    To assess the effect of an angiotensin receptor blocker (ARB) on serum potassium and the effect of a serum potassium change on renal outcomes in patients with type 2 diabetes and nephropathy.......To assess the effect of an angiotensin receptor blocker (ARB) on serum potassium and the effect of a serum potassium change on renal outcomes in patients with type 2 diabetes and nephropathy....

  6. 21 CFR 582.7610 - Potassium alginate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium alginate. 582.7610 Section 582.7610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Potassium alginate. (a) Product. Potassium alginate. (b) Conditions of use. This substance is generally...

  7. 21 CFR 582.1613 - Potassium bicarbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium bicarbonate. 582.1613 Section 582.1613 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1613 Potassium bicarbonate. (a) Product. Potassium bicarbonate. (b) Conditions of use. This...

  8. 21 CFR 184.1613 - Potassium bicarbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium bicarbonate. 184.1613 Section 184.1613... Listing of Specific Substances Affirmed as GRAS § 184.1613 Potassium bicarbonate. (a) Potassium bicarbonate (KHCO3, CAS Reg. No. 298-14-6) is made by the following processes: (1) By treating a solution of...

  9. 21 CFR 172.730 - Potassium bromate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium bromate. 172.730 Section 172.730 Food and... Specific Usage Additives § 172.730 Potassium bromate. The food additive potassium bromate may be safely... malt from the treatment does not exceed 75 parts per million of bromate (calculated as Br), and the...

  10. Thanatochemistry: Study of vitreous humor potassium | Tumram ...

    African Journals Online (AJOL)

    This study has been carried out to determine the death interval from the biochemical parameter of vitreous potassium. In 308 medicolegal cases vitreous humor was taken and analyzed for potassium with known time of death. There was a linear rise in potassium concentration with increasing death interval. Regression ...

  11. A Quantitative Fourier Transform Infrared Study of the Grafting of Aminosilane Layers on Lithium Niobate Surface.

    Science.gov (United States)

    Benmouhoub, Chafia; Gauthier-Manuel, Bernard; Zegadi, Ameur; Robert, Laurent

    2017-07-01

    Due to its impressive optical properties, lithium niobate (LiNbO3) is considered to be one of the most important ferroelectric materials. Its uses in sensing platforms require functionalization at the surface to enable the capture and quantifying of molecules. The current paper aims to demonstrate the covalent bonding of aminosilane layers to the LiNbO3 surface. Fourier transform infrared (FT-IR) analysis reveals the presence of an NbO-Si bond observable as a shoulder at the same wavenumber (975 cm-1) on the surfaces of LiNBO3 as well as on those of Nb2O5, using 3-(aminopropyl)trimethoxysilane (APTMS) or 3-(aminopropyl)methyldimethoxysilane (APDMS) precursors. This covalent bonding is confirmed by the insolubility of the silane coating in dimethyl sulfoxide (DMSO). A kinetic study of the aminosilane layer growth obtained by quantitative FT-IR analysis is also carried out.

  12. Development of photon pair sources using periodically poled lithium niobate waveguide technology and fiber optic components

    Science.gov (United States)

    Oesterling, Lee; Monteiro, Fernando; Krupa, Sean; Nippa, David; Wolterman, Richard; Hayford, Donald; Stinaff, Eric; Sanguinetti, Bruno; Zbinden, Hugo; Thew, Rob

    2015-11-01

    To support quantum technologies that require entangled photon pairs and/or heralded photons for operation, a photon pair source was developed that uses periodically poled lithium niobate (PPLN) waveguides that are coupled to optical fibers. Both Ti-indiffused and annealed proton-exchanged (APE) waveguide technologies were studied, and waveguide/fiber interfaces were designed to increase the coupling efficiency of the photon pairs into optical fiber. PPLN waveguide devices were fabricated and the optical loss, wavelength conversion efficiency, and heralding efficiency were measured. The maximum heralding efficiencies achieved were 75 and 68% for Ti-indiffused and APE waveguides, respectively. A compact photon pair source based on a packaged PPLN waveguide device and commercially available fiber optic components is presented.

  13. A systematic study of the chemical etching process on periodically poled lithium niobate structures

    Energy Technology Data Exchange (ETDEWEB)

    Argiolas, N. [INFM-MATIS and Physics Department, University of Padova, Via Marzolo 8, 35131 Padova (Italy); Bazzan, M. [INFM-MATIS and Physics Department, University of Padova, Via Marzolo 8, 35131 Padova (Italy); Bernardi, A. [INFM-MATIS and Physics Department, University of Padova, Via Marzolo 8, 35131 Padova (Italy); Cattaruzza, E. [INFM-MATIS and Physics Department, University of Padova, Via Marzolo 8, 35131 Padova (Italy); Mazzoldi, P. [INFM-MATIS and Physics Department, University of Padova, Via Marzolo 8, 35131 Padova (Italy); Schiavuta, P. [INFM-MATIS and Physics Department, University of Padova, Via Marzolo 8, 35131 Padova (Italy); Sada, C. [INFM-MATIS and Physics Department, University of Padova, Via Marzolo 8, 35131 Padova (Italy)]. E-mail: sada@padova.infm.it; Hangen, U. [Surface, Rheinstr. 7, D-41836 Hueckelhoven (Germany)

    2005-04-25

    A systematic analysis on the dynamics of the chemical etching of periodically poled lithium niobate (PPLN) structures grown by off-center Czochralski technique was carried out on crystals prepared under different experimental growth conditions. The etched depth reaches values close to 600 nm and it does not further increase even after long etching times. However, the lateral etching cannot be neglected when the etching times are higher than 5 min. The estimation of the domain widths distribution can be affected by artifacts if the etching conditions are not properly chosen. The best structures are obtained for erbium oxide doping level of 0.3 mol% into the starting melt and the period depends on the pulling and rotational rates instead of on the growing rate. This results support the role of the thermoelectric field in the domain formation at the Curie isotherm.

  14. Frequency-agile kilohertz repetition-rate optical parametric oscillator based on periodically poled lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S.T.; Velsko, S.P. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    1999-02-01

    We report kilohertz repetition-rate pulse-to-pulse wavelength tuning from 3.22 to 3.7 {mu}m in a periodically poled lithium niobate (PPLN) optical parametric oscillator (OPO). Rapid tuning over 400thinspcm{sup {minus}1} with random wavelength accessibility is achieved by rotation of the pump beam angle by no more than 24thinspthinspmrad in the PPLN crystal by use of an acousto-optic beam deflector. Over the entire tuning range, a near-transform-limited OPO bandwidth can be obtained by means of injection seeding with a single-frequency 1.5-{mu}m laser diode. The frequency agility, high repetition rate, and narrow bandwidth of this mid-IR PPLN OPO make it well suited as a lidar transmitter source. {copyright} {ital 1999} {ital Optical Society of America}

  15. Influence of magnetic field on terahertz wave generation in photorefractive periodically poled lithium niobate crystal.

    Science.gov (United States)

    Li, Gaofang; Li, Dong; Ma, Guohong; Liu, Weimin; Tang, Sing Hai

    2011-03-10

    By employing femtosecond pump-probe configuration, we successfully realized narrowband terahertz wave generation and detection in both photorefractive periodically poled lithium niobate (PPLN) and periodically poled Mg:LiNb(3) (PP-Mg:LN) crystal. Using an applied magnetic field, we achieved modulation of the terahertz wave in a photorefractive PPLN crystal. The terahertz wave depends strongly on the magnitude of the applied magnetic field in the photorefractive PPLN crystal. Terahertz wave independence of the magnetic field in PP-Mg:LN crystal was also identified. The interaction of the magnetic field and photorefractive PPLN crystal is believed to occur due to the Lorentz force, which results in the buildup of a space-charge field in a photorefractive PPLN crystal.

  16. Photorefractive lithium niobate crystals for applications in photonics; Photorefraktive Lithiumniobatkristalle fuer Anwendungen in der Photonik

    Energy Technology Data Exchange (ETDEWEB)

    Hartwig, U.

    2006-12-15

    Lithium niobate crystals (LiNbO{sub 3}) generally show a photorefractive response, i.e., light-induced refractive index changes. Crystals are investigated at room temperature and at elevated temperatures. As a result 'classical' photorefractive holographic volume-phase gratings, originating from space charge fields and the electro-optic effect, and 'non-classical' photorefractive volume-phase gratings, which can be traced back to strong absorption gratings, emerge. Single domain and periodically poled crystals (PPLN) are investigated. PPLN is typically used in non-linear optics for frequency conversion. The crystals also show non-linear photorefractive response during holographic recording with isotropically polarized light beams of equal intensity and, in the case of PPLN, by mixing of domain and holographic gratings. The results are important for applications combining the photorefractive and non-linear optical properties of LiNbO{sub 3}. (orig.)

  17. Polarization reversal induced by heating-cooling cycles in MgO doped lithium niobate crystals

    Science.gov (United States)

    Shur, V. Ya.; Mingaliev, E. A.; Lebedev, V. A.; Kuznetsov, D. K.; Fursov, D. V.

    2013-05-01

    Polarization reversal during heating-cooling cycles was investigated in MgO doped lithium niobate (MgO:LN) crystal using piezoresponse force microscopy. The essential dependence of the domain structure evolution scenario on the maximal temperature in the cycle has been revealed experimentally. It has been shown that the heating of the engineered domain matrix from room temperature to 85 °C leads to light size reduction of the isolated domains at the matrix edges, whereas the heating to 170 °C leads to essential reduction of the domain size. The opposite strong effect of the domain formation and growth during cooling after pulse heating have been revealed in single domain MgO:LN. The simulation of the time dependence of the pyroelectric field during heating-cooling cycle allowed to reveal the temperature hysteresis and to explain all observed effects taking into account the temperature dependence of the bulk conductivity.

  18. Numerical and Experimental Study of Optoelectronic Trapping on Iron-Doped Lithium Niobate Substrate

    Directory of Open Access Journals (Sweden)

    Michela Gazzetto

    2016-09-01

    Full Text Available Optoelectronic tweezers (OET are a promising technique for the realization of reconfigurable systems suitable to trap and manipulate microparticles. In particular, dielectrophoretic (DEP forces produced by OET represent a valid alternative to micro-fabricated metal electrodes, as strong and spatially reconfigurable electrical fields can be induced in a photoconductive layer by means of light-driven phenomena. In this paper we report, and compare with the experimental data, the results obtained by analyzing the spatial configurations of the DEP-forces produced by a 532 nm laser beam, with Gaussian intensity distribution, impinging on a Fe-doped Lithium Niobate substrate. Furthermore, we also present a promising preliminary result for water-droplets trapping, which could open the way to the application of this technique to biological samples manipulation.

  19. Conversion of broadband thermal radiation in lithium niobate crystals of various compositions

    Science.gov (United States)

    Syuy, A. V.; Litvinova, M. N.; Goncharova, P. S.; Sidorov, N. V.; Palatnikov, M. N.; Krishtop, V. V.; Likhtin, V. V.

    2013-05-01

    The conversion of the broadband thermal radiation in stoichiometric ( R = 1) lithium niobate single crystals that are grown from melt with 58.6 mol % of LiO2, congruent ( R = Li/Nb = 0.946) melt with the K2O flux admixture (4.5 and 6.0 wt %), and congruent melt and in congruent single crystals doped with the Zn2+, Gd3+, and Er3+ cations is studied. It is demonstrated that the conversion efficiency of the stoichiometric crystal that is grown from the melt with 58.6 mol % of LiO2 is less than the conversion efficiency of congruent crystal. In addition, the stoichiometric and almost stoichiometric crystals and the doped congruent crystals exhibit the blue shift of the peak conversion intensity in comparison with a nominally pure congruent crystal. For the congruent crystals, the conversion intensities peak at 520 and 495 nm, respectively.

  20. Electro-optic mode switch based on lithium-niobate Mach-Zehnder interferometer.

    Science.gov (United States)

    Zhang, Mengruo; Chen, Kaixin; Jin, Wei; Chiang, Kin Seng

    2016-06-01

    We propose an electro-optic mode switch based on an optical waveguide Mach-Zehnder interferometer fabricated with x-cut lithium niobate by the annealed proton exchange process. The device can switch between the fundamental mode and the higher-order mode with a low driving voltage. Our typical fabricated device, which has a total length of ∼24  mm, shows a mode extinction ratio of ∼35  dB and a 20-dB bandwidth of ∼12  nm at the wavelength 1552 nm, when driven at a voltage of 1.7 V at 26°C. High performance can be obtained at any wavelength in the C+L band with a driving voltage varying by no more than 3 V. The proposed mode switch is easy to fabricate and could find applications in reconfigurable mode-division-multiplexing systems.

  1. Impact of humidity on surface acoustic wave propagation in vanadium pentoxide xerogel-lithium niobate structure

    Science.gov (United States)

    Sereika, Raimundas; Bondarenka, Vladimiras; Rimeika, Romualdas; Sereika, Albertas; Čiplys, Daumantas

    2014-11-01

    The impact of ambient humidity on surface acoustic wave (SAW) propagation in the structure consisting of vanadium pentoxide xerogel (V2O5•nH2O) layer deposited on a piezoelectric lithium niobate (LiNbO3) substrate has been studied. Thin V2O5•nH2O layers were synthesized using sol-gel method and employed as humidity sensing materials. Freshly prepared layer drastically reduced the transmitted SAW signal, which later increased with time reaching saturation after more than 120 h at the level well below the free-surface value. The experimental observations of SAW behaviour were discussed and found related to the variations in resistance and dielectric permittivity of the V2O5•nH2O.

  2. Low-temperature anodic bonding using thin films of lithium-niobate-phosphate glass

    Science.gov (United States)

    Woetzel, S.; Kessler, E.; Diegel, M.; Schultze, V.; Meyer, H.-G.

    2014-09-01

    This paper reports on the investigation of a low-temperature anodic bonding process with layers of a lithium-niobate-phosphate glass on chip level. The glass layers are deposited by means of rf sputtering. The applied glass is characterised by its high ion conductivity, enabling anodic bonding at room temperature. Results of the optimisation process concerning the intrinsic stress of the glass layers and the thermal exposure of the substrates through the deposition process are presented. The stoichiometry of the glass layers is verified through Rutherford backscattering spectroscopy (RBS). The bonding strength is measured by tensile tests. Microfabricated atomic vapour cells are used for hermeticity tests of the bonding by absorption measurements of the caesium D1 line.

  3. Two waveguide layers in lithium niobate crystal formed by swift heavy Kr ion irradiation

    Science.gov (United States)

    Liu, Tao; Huang, Qing; Zhao, Jin-Hua; Kong, Wei-Jin; Liu, Peng; Zhang, Lian; Zhou, Yu-Fan; Yu, Xiao-Fei; Wang, Lei; Wang, Xue-Lin

    2015-05-01

    We report the formation of two waveguide layers in a lithium niobate crystal by irradiation with swift heavy Kr ions with high (GeV) energies and ultralow fluences. The micro-Raman spectra are measured at different depths in the irradiated layer and show that the high electronic energy loss can cause lattice damage along the ion trajectory, while the nuclear energy loss causes damage at the end of the ion track. Two waveguide layers are formed by confinement with two barriers associated with decreases in the refractive index that are caused by electronic and nuclear energy losses, respectively. Project supported by the National Natural Science Foundation of China (Grant Nos. 11275117, U1432120, and 11274188) and the Heavy Ion Research Facility in Lanzhou (HIRFL), China.

  4. Hybrid microfiber-lithium-niobate nanowaveguide structures as high-purity heralded single-photon sources

    Science.gov (United States)

    Main, Philip; Mosley, Peter J.; Ding, Wei; Zhang, Lijian; Gorbach, Andrey V.

    2016-12-01

    We propose a compact, fiber-integrated architecture for photon-pair generation by parametric downconversion with unprecedented flexibility in the properties of the photons produced. Our approach is based on a thin-film lithium niobate nanowaveguide, evanescently coupled to a tapered silica microfiber. We demonstrate how controllable mode hybridization between the fiber and waveguide yields control over the joint spectrum of the photon pairs. We also investigate how independent engineering of the linear and nonlinear properties of the structure can be achieved through the addition of a tapered, proton-exchanged layer to the waveguide. This allows further refinement of the joint spectrum through custom profiling of the effective nonlinearity, drastically improving the purity of the heralded photons. We give details of a source design capable of generating heralded single photons in the telecom wavelength range with purity of at least 0.95, and we provide a feasible fabrication methodology.

  5. Lightwave Circuits in Lithium Niobate through Hybrid Waveguides with Silicon Photonics

    Science.gov (United States)

    Weigel, Peter O.; Savanier, Marc; Derose, Christopher T.; Pomerene, Andrew T.; Starbuck, Andrew L.; Lentine, Anthony L.; Stenger, Vincent; Mookherjea, Shayan

    2016-03-01

    We demonstrate a photonic waveguide technology based on a two-material core, in which light is controllably and repeatedly transferred back and forth between sub-micron thickness crystalline layers of Si and LN bonded to one another, where the former is patterned and the latter is not. In this way, the foundry-based wafer-scale fabrication technology for silicon photonics can be leveraged to form lithium-niobate based integrated optical devices. Using two different guided modes and an adiabatic mode transition between them, we demonstrate a set of building blocks such as waveguides, bends, and couplers which can be used to route light underneath an unpatterned slab of LN, as well as outside the LN-bonded region, thus enabling complex and compact lightwave circuits in LN alongside Si photonics with fabrication ease and low cost.

  6. Formation of needle-shaped domains in a surface layer of X-cut lithium niobate

    Science.gov (United States)

    Paranin, V. D.

    2014-12-01

    The formation of needle-shaped domains in a surface layer of X-cut lithium niobate in the electric field of contact electrodes is studied. It is found that a voltage of 1200-1250 V produces stable needle-shaped domains in an interelectrode gap 140 ± 5 μm wide. The domains are from 20 to 30 μm long and are aligned with the polar axis of the crystal and with electric lines of force. When a voltage of 1300-1350 V is applied to the crystal, the size of the domains increases stepwise and their growth rate rises considerably to about 1 μm/s. The domains localize within 300-600 μm from the edge of the electrodes because of the increase in the electric field strength at right angles. The sizes of the domains differ greatly because of microscopic defects present at the electrode boundaries.

  7. The inhibitory effects of potassium chloride versus potassium silicate application on (137)Cs uptake by rice.

    Science.gov (United States)

    Fujimura, Shigeto; Yoshioka, Kunio; Ota, Takeshi; Ishikawa, Tetsuya; Sato, Makoto; Satou, Mutsuto

    2016-03-01

    After the accident at the Fukushima Dai-ichi Nuclear Power Plant owned by the Tokyo Electric Power Company on 11 March 2011, potassium fertilizer was applied to agricultural fields in the southern Tohoku and northern Kanto regions of Japan to reduce the uptake of radiocesium by crops. In this study, we examined the effects of two types of potassium fertilizers, potassium chloride (a readily available potassium fertilizer) and potassium silicate (a slow-release potassium fertilizer), as well as a split application of potassium, on the accumulation of (137)Cs by rice plants in two pot experiments. The (137)Cs concentrations in the brown rice and in the above-ground plants were significantly lower after potassium chloride application than after potassium silicate application. The potassium ion (K(+)) concentrations in soil solutions sampled 9 and 21 d after transplanting were significantly higher for the potassium chloride application than for the potassium silicate application. The K(+) concentrations in soil solutions observed in the application of potassium silicate were similar to those in the treatment when no potassium was applied. This finding indicates that the application of potassium silicate did not sufficiently increase the available K(+) for rice plants in the soil, which led to a greater uptake of (137)Cs after the potassium silicate application than after the application of potassium chloride. The (137)Cs concentration in brown rice was higher in the split application of potassium fertilizer with the second application at the full heading stage than that without split application and the split application with the second application before heading. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Pickering emulsions prepared by layered niobate K₄Nb₆O₁₇ intercalated with organic cations and photocatalytic dye decomposition in the emulsions.

    Science.gov (United States)

    Nakato, Teruyuki; Ueda, Hiroaki; Hashimoto, Sachika; Terao, Ryosuke; Kameyama, Miyuki; Mouri, Emiko

    2012-08-01

    We investigated emulsions stabilized with particles of layered hexaniobate, known as a semiconductor photocatalyst, and photocatalytic degradation of dyes in the emulsions. Hydrophobicity of the niobate particles was adjusted with the intercalation of alkylammonium ions into the interlayer spaces to enable emulsification in a toluene-water system. After the modification of interlayer space with hexylammonium ions, the niobate stabilized water-in-oil (w/o) emulsions in a broad composition range. Optical microscopy showed that the niobate particles covered the surfaces of emulsion droplets and played a role of emulsifying agents. The niobate particles also enabled the generation of oil-in-water (o/w) emulsions in a limited composition range. Modification with dodecylammonium ions, which turned the niobate particles more hydrophobic, only gave w/o emulsions, and the particles were located not only at the toluene-water interface but also inside the toluene continuous phase. On the other hand, interlayer modification with butylammonium ions led to the formation of o/w emulsions. When porphyrin dyes were added to the system, the cationic dye was adsorbed on niobate particles at the emulsion droplets whereas the lipophilic dye was dissolved in toluene. Upon UV irradiation, both of the dyes were degraded photocatalytically. When the cationic and lipophilic porphyrin molecules were simultaneously added to the emulsions, both of the dyes were photodecomposed nonselectively.

  9. Potassium Intake, Bioavailability, Hypertension, and Glucose Control

    Directory of Open Access Journals (Sweden)

    Michael S. Stone

    2016-07-01

    Full Text Available Potassium is an essential nutrient. It is the most abundant cation in intracellular fluid where it plays a key role in maintaining cell function. The gradient of potassium across the cell membrane determines cellular membrane potential, which is maintained in large part by the ubiquitous ion channel the sodium-potassium (Na+-K+ ATPase pump. Approximately 90% of potassium consumed (60–100 mEq is lost in the urine, with the other 10% excreted in the stool, and a very small amount lost in sweat. Little is known about the bioavailability of potassium, especially from dietary sources. Less is understood on how bioavailability may affect health outcomes. Hypertension (HTN is the leading cause of cardiovascular disease (CVD and a major financial burden ($50.6 billion to the US public health system, and has a significant impact on all-cause morbidity and mortality worldwide. The relationship between increased potassium supplementation and a decrease in HTN is relatively well understood, but the effect of increased potassium intake from dietary sources on blood pressure overall is less clear. In addition, treatment options for hypertensive individuals (e.g., thiazide diuretics may further compound chronic disease risk via impairments in potassium utilization and glucose control. Understanding potassium bioavailability from various sources may help to reveal how specific compounds and tissues influence potassium movement, and further the understanding of its role in health.

  10. Evaluation of the potassium adsorption capacity of a potassium adsorption filter during rapid blood transfusion.

    Science.gov (United States)

    Matsuura, H; Akatsuka, Y; Muramatsu, C; Isogai, S; Sugiura, Y; Arakawa, S; Murayama, M; Kurahashi, M; Takasuga, H; Oshige, T; Yuba, T; Mizuta, S; Emi, N

    2015-05-01

    The concentration of extracellular potassium in red blood cell concentrates (RCCs) increases during storage, leading to risk of hyperkalemia. A potassium adsorption filter (PAF) can eliminate the potassium at normal blood transfusion. This study aimed to investigate the potassium adsorption capacity of a PAF during rapid blood transfusion. We tested several different potassium concentrations under a rapid transfusion condition using a pressure bag. The adsorption rates of the 70-mEq/l model were 76·8%. The PAF showed good potassium adsorption capacity, suggesting that this filter may provide a convenient method to prevent hyperkalemia during rapid blood transfusion. © 2015 International Society of Blood Transfusion.

  11. Potassium

    Science.gov (United States)

    ... Don't Work Out Alone - Fitness Peer Support Breaking Down Barriers to Fitness Overcoming a Fitness Plateau Celebrating Your Fitness Success Step It Up - Tips to Pump Up Your Workout Walking Walking ...

  12. Comparative study on three highly sensitive absorption measurement techniques characterizing lithium niobate over its entire transparent spectral range.

    Science.gov (United States)

    Leidinger, M; Fieberg, S; Waasem, N; Kühnemann, F; Buse, K; Breunig, I

    2015-08-24

    We employ three highly sensitive spectrometers: a photoacoustic spectrometer, a photothermal common-path interferometer and a whispering-gallery-resonator-based absorption spectrometer, for a comparative study of measuring the absorption coefficient of nominally transparent undoped, congruently grown lithium niobate for ordinarily and extraordinarily polarized light in the wavelength range from 390 to 3800 nm. The absorption coefficient ranges from below 10(-4) cm(-1) up to 2 cm(-1). Furthermore, we measure the absorption at the Urbach tail as well as the multiphonon edge of the material by a standard grating spectrometer and a Fourier-transform infrared spectrometer, providing for the first time an absorption spectrum of the whole transparency window of lithium niobate. The absorption coefficients obtained by the three highly sensitive and independent methods show good agreement.

  13. Impact of the photorefractive and pyroelectric-electro-optic effect in lithium niobate on whispering-gallery modes.

    Science.gov (United States)

    Leidinger, Markus; Werner, Christoph S; Yoshiki, Wataru; Buse, Karsten; Breunig, Ingo

    2016-12-01

    Whispering-gallery resonators made of undoped and MgO-doped congruently grown lithium niobate are used to study electro-optic refractive index changes. Hereby, we focus on the volume photovoltaic and the pyroelectric effect, both providing an electric field driving the electro-optic effect. Our findings indicate that the light-induced photorefractive effect, combining the photovoltaic and electro-optic effect, is present only in the non-MgO-doped lithium niobate for exposure with light having wavelengths of up to 850 nm. This leads to strong resonance frequency shifts of the whispering-gallery modes. No photorefractive effect was observed in the MgO-doped material. One has to be aware that surface charges induced by the pyroelectric effect result in a similar phenomenon and are present in both materials.

  14. Humidity-dependent reversible aggregation of rhodamine 6G dye immobilized within layered niobate K4Nb6O17.

    Science.gov (United States)

    Shinozaki, Ryota; Nakato, Teruyuki

    2004-08-31

    The spectroscopic behavior of rhodamine 6G (R6G) dye intercalated in layered hexaniobate K4Nb6O17 was investigated. R6G cations were intercalated into the niobate through displacement of preintercalated alkylammonium ions. Powder X-ray diffraction and elemental analysis indicated that the dye molecules were densely accommodated in the interlayer spaces of niobate. The spectroscopic behavior of intercalated R6G was characterized by humidity-dependent aggregation at room temperature. The dye molecules were present dominantly as monomers under humid conditions (93% relative humidity (RH)), while they formed dimers under relatively dry conditions (20% RH). The aggregation-deaggregation of dye occurred reversibly depending on the humidity. The reversible aggregation was not accompanied by a large alteration of the interlayer structure of the sample, because only a small amount of water was adsorbed/desorbed with a small change in the basal spacing of the intercalation compound during the humidity change.

  15. Few-cycle solitons and supercontinuum generation with cascaded quadratic nonlinearities in unpoled lithium niobate ridge waveguides

    DEFF Research Database (Denmark)

    Guo, Hairun; Zeng, Xianglong; Zhou, Binbin

    2014-01-01

    Formation and interaction of few-cycle solitons in a lithium niobate ridge waveguide are numerically investigated. The solitons are created through a cascaded phase-mismatched second-harmonic generation process, which induces a dominant self-defocusing Kerr-like nonlinearity on the pump pulse...... pumped with femtosecond nanojoule pulses at 1550 nm. The waveguide is not periodically poled, as quasi-phase-matching would lead to detrimental nonlinear effects impeding few-cycle soliton formation....

  16. Activation energy of proton migration in Mn- and Fe-doped lithium niobate obtained by holographic methods

    Science.gov (United States)

    Mandula, G.; Ellabban, M. A.; Rupp, R. A.; Fally, M.; Hartmann, E.; Kovacs, L.; Polgar, K.

    2003-01-01

    The activation energy of thermal fixing of photorefractive gratings is determined in congruent and nearly stoichiometric lithium niobate crystals, both doped with iron or manganese. The novel technique called holographic scattering method is compared with the standard two-wave mixing method. A measurement of the angular distribution of the self scattered intensity and its possible-analytical function is presented. The mathematical problems of the holographic scattering method are discussed applying the angular distribution functions.

  17. Electro-optic modulation of high-Q lithium niobate whispering gallery resonator with integrated ground plane (Conference Presentation)

    Science.gov (United States)

    Douglas, Kenneth; Moore, Jeremy; Friedman, Thomas; Eichenfield, Matthew

    2017-02-01

    We experimentally demonstrate electro-optic modulation in thin film lithium niobate microdisk resonators with an integrated bottom electrode fabricated from a z-cut Lithium Niobate on Insulator wafer. The structure consisted of a 400nm thick crystalline z-cut lithium niobate/2um SiO2/20nm Cr/100nm Au/10nm Cr film stack on top of a z-cut lithium niobate handle wafer. The integrated bottom electrode is located 2um beneath the resonator. This proximity, coupled with positioning an electrical probe close to the top of the resonator, allows large optical frequency shifts with low voltages. We observed a 0.111pm/V resonance shift of vertically polarized (TM) optical whispering gallery modes, with the voltage applied perpendicular to the wafer surface. This corresponds to a shift of one optical linewidth at an applied voltage of 180V, using the r33 component of the eletro-optic tensor. We observed a smaller shift of 0.066pm/V for the radially polarized (TE) modes, using the r13 component of the electro-optic tensor. The experiment was performed using a 1550nm tunable laser that was coupled to the optical resonator modes using a tapered optical fiber. To measure the electro-optic shift of the resonance, a voltage was applied across the device via DC probe tips and the peak shift was calibrated with a Toptica WS6 IR wavemeter with 200 MHz absolute accuracy. We also present a finite element model that accurately predicts the resonance shift as a function of applied voltage for both polarizations.

  18. Design of Optical Boolean Function Generator Using Lithium Niobate-Based Mach-Zehnder Interferometer for WDM Applications

    Science.gov (United States)

    Pal, Amrindra; Kumar, Santosh; Sharma, Sandeep

    2017-05-01

    This paper includes optical Boolean function generator unit. It can generate multiple logical operations (16 operations). The device is proposed using electro-optic effect inside lithium niobate-based Mach-Zehnder interferometers (MZIs). The MZI structures have powerful capability to switching an optical input signal to a desired output port. The paper constitutes mathematical description of the device and thereafter simulation using MATLAB. The study is verified using beam propagation method.

  19. Highly coherent mid-IR supercontinuum by self-defocusing solitons in lithium niobate waveguides with all-normal dispersion

    DEFF Research Database (Denmark)

    Guo, Hairun; Zhou, Binbin; Zeng, Xianglong

    2014-01-01

    We numerically investigate self-defocusing solitons in a lithium niobate (LN) waveguide designed to have a large refractive index (RI) change. The waveguide evokes strong waveguide dispersion and all-normal dispersion is found in the entire guiding band spanning the near-IR and the beginning...... dispersion, the soliton spectral tunneling effect is also investigated, with which few-cycle pico-joule pulses at 2 mm are formed by a near-IR pump. © 2014 Optical Society of America....

  20. Hemoglobin niobate composite based biosensor for efficient determination of hydrogen peroxide in a broad pH range.

    Science.gov (United States)

    Gao, Lu; Gao, Qiuming

    2007-02-15

    Inorganic layered niobates (HCa2Nb3O10) were used as immobilization matrices of hemoglobin (Hb) because of their tunable interlayer spaces, large surface areas and good biocompatibilities. A pair of well-defined, quasi-reversible cycle voltammertric peaks were obtained at the Hb-HCa2Nb3O10 modified pyrolytic graphite electrode, suggesting that the layered niobates facilitate the electron transfer between the proteins and the electrode. Hb-HCa2Nb3O10 modified electrode exhibited electrocatalytic response for monitoring H2O2 with a large linear detection range from 25 microM to 3.0 mM and a relatively high sensitivity of 172 microA mM-1 cm-2. Based on the stabilizing effect of the layered niobates, Hb-HCa2Nb3O10 modified electrode can detect H2O2 in strongly acidic and basic solutions with pH of 1-12, which greatly expands the application fields of biosensors.

  1. Detection of Mercury's Potassium Tail

    Science.gov (United States)

    Schmidt, Carl; Leblanc, Francois; Moore, Luke; Bida, Thomas A.

    2017-10-01

    Ground-based observations of Mercury's exosphere bridge the gap between the MESSENGER and BepiColombo missions and provide a broad counterpart to their in situ measurements. Here we report the first detection of Mercury's potassium tail in both emission lines of the D doublet. The sodium to potassium abundance ratio at 5 planetary radii down-tail is approximately 95, near the mid-point of a wide range of values that have been quoted over the planet's disk. This is several times the Na/K present in atmospheres of the Galilean satellites and more than an order of magnitude above Mercury's usual analogue, the Moon. The observations confirm that Mercury's anomalously high Na/K ratios cannot be explained by differences in neutral loss rates. The width and structure of the Na and K tails is comparable and both exhibit a persistent enhancement in their northern lobe. We interpret this as a signature of Mercury's offset magnetosphere; the exosphere's source rates are locally enhanced at the southern surface, and sloshing from radiation pressure and gravity guides this population into the northern region of the tail.

  2. Potassium loss with tissue potassium deficiency in rats during hypokinesia.

    Science.gov (United States)

    Tsiamis, Costas B; Kakuris, Kostas K; Deogenov, Viktor A; Yerullis, Kosmas B

    2008-04-01

    This study aims at showing the effect of hypokinesia (HK) on tissue potassium (K(+)) loss with different tissue K(+) depletion and tissue K(+) deficiency with different K(+) intake. To this end, tissue K(+) content, plasma K(+) level, and K(+) loss with and without K(+) supplements during HK were measured. Studies were conducted on male Wistar rats during a pre-experimental and an experimental period. Animals were equally divided into four groups: unsupplemented vivarium control rats (UVCR), unsupplemented hypokinetic rats (UHKR), supplemented vivarium control rats (SVCR), and supplemented hypokinetic rats (SHKR). SVCR and SHKR were supplemented daily with 2.50 mEq potassium chloride (KCl). Gastrocnemius muscle and right femur bone K(+) content reduced significantly, whereas plasma K(+) level and urine and fecal K(+) loss increased significantly in SHKR and UHKR compared with their pre-experimental values and the values in their respective vivarium controls (SVCR and UVCR). Bone and muscle K(+) content decreased more significantly, and plasma K(+) level and urine and fecal K(+) loss increased more significantly in SHKR than in UHKR. The greater tissue K(+) deficiency with higher than lower K(+) intake shows that the risk of higher tissue K(+) deficiency is directly related to K(+) intake. The higher K(+) loss with higher tissue K(+) deficiency and the lower K(+) loss with lower K(+) tissue deficiency shows that the risk of greater K(+) loss is directly related to tissue K(+) deficiency. Tissue K(+) deficiency increases more when the K(+) intake is higher and K(+) loss increases more with higher than lower tissue K(+) deficiency indicating that, during HK, tissue K(+) deficiency is due to the inability of the body to use K(+) but not to K(+) shortage in the diet.

  3. Ion irradiation effects on lithium niobate etalons for tunable spectral filters

    Science.gov (United States)

    Garranzo, D.; Ibarmia, S.; Alvarez-Herrero, A.; Olivares, J.; Crespillo, M.; Díaz, M.

    2017-11-01

    , coupled with the HV field, could trigger a dielectric breakdown in the Lithium Niobate. In this paper we present the electro-optical results obtained when exposing a set of LN samples and a lowquality full size etalon to different radiation conditions. In a first irradiation campaign, performed at the Centre for Micro Analysis of Materials (CMAM-Madrid) facilities, we were mainly focused on the long-term degradation effects with a series of high flux (109 cm-2 s-1) proton tests at an energy of 10 MeV. In order to study the possibility of a single ion breakdown, a second campaign was carried out, at the Texas A&M University (TAMU), exposing Lithium Niobate to high LET ion species (78Kr, 40Ar, 129Xe, 197Au) accelerated to the GeV energy range to penetrate or even pass through the entire Lithium Niobate thickness.

  4. Radiolysis of Potassium Picrate in 77 K

    Science.gov (United States)

    Yakubik, D. G.; Pak, V. Kh; Anan'ev, V. A.; Ghyngazov, S. A.

    2016-02-01

    The formation of paramagnetic centers in potassium picrate under irradiation at low temperature was investigated. The heating irradiated at 77 K potassium picrate crystal to room temperature results in paramagnetic centers - 2,6-dinitro-para-quinone radicals, ortho- and para-iminoxyl radicals and atomic oxygen. These products are formed under irradiation at room temperature.

  5. Genetics Home Reference: potassium-aggravated myotonia

    Science.gov (United States)

    ... eating potassium-rich foods such as bananas and potatoes. Stiffness occurs in skeletal muscles throughout the body. Potassium-aggravated myotonia ranges in severity from mild episodes of muscle stiffness to severe, disabling disease with frequent attacks. Unlike some other forms of ...

  6. Potassium nutrition of heat-stressed lactating

    African Journals Online (AJOL)

    measure of dry bulb air temperature, wind velocity and solar radiation ... high milk potassium content (0,15-0,17%), (b) heat stress owing to increased ... level) as sub plots. All cows received different dietary potassium treatments in each 30-day period. Basal diet was 52% ground corn, 9,5% corn gluten meal, 1,0% urea,.

  7. Erythrocyte potassium and glutathione polymorphism determination ...

    African Journals Online (AJOL)

    This research is aimed at determining the erythrocyte potassium and glutathione polymorphisms and also to identify the relationship among the various blood parameters in Saanen x Malta crossbred goat raised in Turkey. The allele gene frequencies of KH and KL associated with the potassium concentration were ...

  8. Thanatochemistry: Study of synovial fluid potassium | Tumram ...

    African Journals Online (AJOL)

    The purpose of this paper is to test previously developed regression formulae for estimating death interval based on synovial fluid potassium and to assess its reliability in estimating death interval. Synovial fluid potassium was measured on a sample of 308 individuals. Death interval was regressed on synovial fluid ...

  9. [Topology of the mitochondrial potassium ion channels].

    Science.gov (United States)

    Laskowski, Michał; Kulawiak, Bogusz

    In the inner mitochondrial membrane several potassium channels have been identified whose activation lead to cytoprotection during ischemic event. It was found that activation of mitochondrial large conductance calcium activated potassium channel (mitoBKCa) and ATP regulated potassium channel (mitoKATP) preserves brain and heart muscle cells against ischemia/reperfusion induced damage. However the detailed cytoprotection mechanism remains unclear. Similarly, the molecular structures and protein interactions of the mitochondrial potassium channels are still unknown. In this article, we summarize the current knowledge of the mitoKATP and mitoBKCa channels topology. Different aspects of this topic are discussed like import and assembly of the channel subunits and biophysical properties of mitochondrial compartments. Additionally, the consequences of different topology models on the cytoprotective function of the mitochondrial potassium channels were analyzed.

  10. A possible low intracellular potassium in obesity.

    Science.gov (United States)

    Colt, E W; Wang, J; Stallone, F; Van Itallie, T B; Pierson, R N

    1981-03-01

    In comparison with lean marathon runners whose fat content was 15%, obese subjects with a fat content of 55% showed a 36% reduction in intracellular potassium. It is hypothesized that as much as 60% of this decrease may have been due to the lower proportion of muscle (which has the highest intracellular potassium of any tissue) in the fat free mass of very obese subjects. The remainder of the decrease seems to have been a measurement artefact owing to self-absorption of gamma rays by adipose tissue, most of which is distributed over potassium rich lean tissue. The low intracellular potassium values found in obesity should not be interpreted as necessarily signifying potassium deficiency.

  11. Electric field-induced phase transitions and composition-driven nanodomains in rhombohedral-tetragonal potassium-sodium niobate-based ceramics

    KAUST Repository

    Lv, Xiang

    2017-08-07

    The mechanisms behind the high piezoelectricity of (K,Na)NbO3-based lead-free ceramics were investigated, including electric field-induced phase transitions and composition-driven nanodomains. The construction of a rhombohedral-tetragonal (R-T) phase boundary, confirmed using several advanced techniques, allowed a large piezoelectric constant (d33) of 450 ± 5 pC/N to be obtained in (1-x)K0.4Na0.6Nb0.945Sb0.055O3-xBi0.5Na0.5(Hf1-ySny)O3 (0 ≤ x ≤ 0.06 and 0 ≤ y ≤ 0.5) ceramics possessing an ultralow ΔUT-R of 7.4 meV. More importantly, the existence of an intermediate phase, i.e., the electric-induced phase (EIP), bridging the rhombohedral R [Ps//(111)] and tetragonal T [Ps//(001)] phases during the polarization rotation was demonstrated. Striped nanodomains (∼40 nm) that easily responded to external stimulation were also observed in the ceramics with an R-T phase. Thus, the enhanced piezoelectric properties originated from EIP and the striped nanodomains.

  12. Ferroelectric and dielectric characterization studies on relaxor- and ferroelectric-like strontium-barium niobates

    Directory of Open Access Journals (Sweden)

    K. Matyjasek

    2013-01-01

    Full Text Available Ferroelectric domain structure evolution induced by an external electric field was investigated by means of nematic liquid crystal (NLC method in two strontium-barium niobate single crystals of nominal composition: Sr0.70Ba0.30Nb2O6 (SBN:70 - relaxor and Sr0.26Ba0.74Nb2O6 (SBN:26 - ferroelectric. Our results provide evidence that the broad phase transition and frequency dispersion that are exhibited in SBN:70 crystal have a strong link to the configuration of ferroelectric microdomains. The large leakage current revealed in SBN:26 may compensate internal charges acting as pinning centers for domain walls, which gives rise to a less restricted domain growth similar to that observed in classical ferroelectrics. Microscale studies of a switching process in conjunction with electrical measurements allowed us to establish a relationship between local properties of the domain dynamics and macroscopic response i.e., polarization hysteresis loop and dielectric properties.

  13. Low energy electron imaging of domains and domain walls in magnesium-doped lithium niobate

    Science.gov (United States)

    Nataf, G. F.; Grysan, P.; Guennou, M.; Kreisel, J.; Martinotti, D.; Rountree, C. L.; Mathieu, C.; Barrett, N.

    2016-09-01

    The understanding of domain structures, specifically domain walls, currently attracts a significant attention in the field of (multi)-ferroic materials. In this article, we analyze contrast formation in full field electron microscopy applied to domains and domain walls in the uniaxial ferroelectric lithium niobate, which presents a large 3.8 eV band gap and for which conductive domain walls have been reported. We show that the transition from Mirror Electron Microscopy (MEM - electrons reflected) to Low Energy Electron Microscopy (LEEM - electrons backscattered) gives rise to a robust contrast between domains with upwards (Pup) and downwards (Pdown) polarization, and provides a measure of the difference in surface potential between the domains. We demonstrate that out-of-focus conditions of imaging produce contrast inversion, due to image distortion induced by charged surfaces, and also carry information on the polarization direction in the domains. Finally, we show that the intensity profile at domain walls provides experimental evidence for a local stray, lateral electric field.

  14. Homogeneous linewidth measurements of Yb3+ ions in congruent and stoichiometric lithium niobate crystals

    Science.gov (United States)

    Kis, Zsolt; Mandula, Gabor; Lengyel, Krisztian; Hajdara, Ivett; Kovacs, Laszlo; Imlau, Mirco

    2014-11-01

    We report the result of a series of pump-probe spectral hole burning measurements on Yb3+ doped stoichiometric and congruent lithium niobate single crystal. The measurements were performed with a stabilized diode laser tuned to the ≈980 nm transition of the dopant ions. The crystal samples were placed in a closed cycle helium cryostat, the experiments have been done in the temperature range 9-20 K. The observed spectral holes have complex structure, at least two Lorentzian curves are needed to reproduce their shape (double spectral hole). A simple theoretical model has been developed to describe the line-shape resulting from the interaction between the light pulses and the dopant ions. Using the predictions of the theory, the homogeneous linewidths and the population relaxation rates have been estimated for both crystal samples. Using these results, the temperature dependence of the spectral hole widths and the spectral diffusion rates have also been determined. Some considerations are presented to explain the origin of the double spectral hole structure.

  15. Nanosecond electrical and optical pulses and self phase conjugation from photorefractive lithium niobate fibers and crystals

    Science.gov (United States)

    Kukhtarev, N.; Kukhtareva, T.; Curley, M.; Jaenisch, H. M.; Edwards, M. E.; Gu, M.; Zhou, Z.; Guo, R.

    2007-09-01

    We have observed nanosecond electrical and optical pulsations from photorefractive lithium-niobate optical fibers using CW green and blue low-power lasers. Fourier spectra of the pulsations have a maximum at ~900 MHz with peaks separated by ~30MHz. We consider free-space and fiber supported illumination of the fiber crystal. Strong nonlinear enhanced backscattering with phase conjugation was observed from bulk crystals and crystal fibers along the C-axis. Model of transformation of CW laser irradiation of ferroelectric crystals into periodic nanosecond electrical and optical pulsations is suggested. This model includes combinations of photorefractive, pyroelectric, piezoelectric, and photogalvanic mechanisms of the holographic grating formation and crystal electrical charging. Possible applications of these short photo-induced electrical pulses for modulation of holographic beam coupling, pulsed electrolysis, electrophoresis, focused electron beams, X-ray and neutron generation, and hand-held micro X-ray devices for localized oncology imaging and treatment based on our advanced sensor work are discussed.

  16. Generation and tunable enhancement of a sum-frequency signal in lithium niobate nanowires

    Science.gov (United States)

    Sergeyev, Anton; Reig Escalé, Marc; Grange, Rachel

    2017-02-01

    Recent developments in the fabrication of lithium niobate (LiNbO3) structures down to the nanoscale opens up novel applications of this versatile material in nonlinear optics. Current nonlinear optical studies in sub-micron waveguides are mainly restricted to the generation of second and third harmonics. In this work, we demonstrate the generation and waveguiding of the sum-frequency generation (SFG) signal in a single LiNbO3 nanowire with a cross-section of 517 nm  ×  654 nm. Furthermore, we enhance the guided SFG signal 17.9 times by means of modal phase matching. We also display tuning of the phase-matched wavelength by varying the nanowire cross-section and changing the polarization of the incident laser. The results prove that LiNbO3 nanowires can be successfully used for nonlinear wave-mixing applications and assisting the miniaturization of optical devices. , which features invited work from the best early-career researchers working within the scope of J Phys D. This project is part of the Journal of Physics series’ 50th anniversary celebrations in 2017. Rachel Grange was selected by the Editorial Board of J Phys D as an Emerging Leader.

  17. Anisotropic surface acoustic waves in tungsten/lithium niobate phononic crystals

    Science.gov (United States)

    Sun, Jia-Hong; Yu, Yuan-Hai

    2018-02-01

    Phononic crystals (PnC) were known for acoustic band gaps for different acoustic waves. PnCs were already applied in surface acoustic wave (SAW) devices as reflective gratings based on the band gaps. In this paper, another important property of PnCs, the anisotropic propagation, was studied. PnCs made of circular tungsten films on a lithium niobate substrate were analyzed by finite element method. Dispersion curves and equal frequency contours of surface acoustic waves in PnCs of various dimensions were calculated to study the anisotropy. The non-circular equal frequency contours and negative refraction of group velocity were observed. Then PnC was applied as an acoustic lens based on the anisotropic propagation. Trajectory of SAW passing PnC lens was calculated and transmission of SAW was optimized by selecting proper layers of lens and applying tapered PnC. The result showed that PnC lens can suppress diffraction of surface waves effectively and improve the performance of SAW devices.

  18. Bandwidth tunable THz wave generation in large-area periodically poled lithium niobate.

    Science.gov (United States)

    Zhang, Caihong; Avetisyan, Yuri; Glosser, Andreas; Kawayama, Iwao; Murakami, Hironaru; Tonouchi, Masayoshi

    2012-04-09

    A new scheme of optical rectification (OR) of femtosecond laser pulses in a periodically poled lithium niobate (PPLN) crystal, which generates high energy and bandwidth tunable multicycle THz pulses, is proposed and demonstrated. We show that the number of the oscillation cycles of the THz electric field and therefore bandwidth of generated THz spectrum can easily and smoothly be tuned from a few tens of GHz to a few THz by changing the pump optical spot size on PPLN crystal. The minimal bandwidth is 17 GHz that is smallest ever of reported in scheme of THz generation by OR at room temperature. Similar to the case of Cherenkov-type OR in single-domain LiNbO₃, the spectrum of THz generation extends from 0.1 THz to 3 THz when laser beam is focused to a size close to half-period of PPLN structure. The energy spectral density of narrowband THz generation is almost independent of the bandwidth and is typically 220 nJ/THz for ~1 W pump power at 1 kHz repetition rate.

  19. Development and Characterization of a Periodically Poled Lithium Niobate Photon Pair Source

    Science.gov (United States)

    Krupa, Sean; Stinaff, Eric; Oesterling, Lee; Nippa, David

    2015-05-01

    A photon pair source made of Periodically Poled Lithium Niobate (PPLN) was developed for degenerate and non-degenerate type-0 Spontaneous Parametric Downconversion (SPDC) of 775-780 nm light to telecom wavelengths. Research consisting of characterization and an iterative design/development process resulted in a PPLN photon pair source suitable for commercial application. Focusing on losses and heralding efficiency, different waveguide geometries and manufacturing techniques were tested, characterized, and optimized. The best PPLN devices created feature insertion losses of 3 dB and heralding efficiencies of 70% making them exceptional for use in emerging quantum applications. Further integration of fiber optic components will be done to expand the capabilities of the devices. Other current research is focused on further characterization of the devices, specifically the SPDC spectra and a direct measurement of the effective nonlinear coefficient in the PPLN waveguides. These measurements will be discussed in detail as well an overview of the project. This work seeks to improve the performance of PPLN waveguides for use in quantum technologies.

  20. Label-free investigation of the effects of lithium niobate polarization on cell adhesion

    Science.gov (United States)

    Mandracchia, B.; Gennari, O.; Paturzo, M.; Grilli, S.; Ferraro, P.

    2017-06-01

    The determination of contact area is pivotal to understand how biomaterials properties influence cell adhesion. In particular, the influence of surface charges is well-known but still controversial, especially when new functional materials and methods are introduced. Here, we use for the first time Holographic Total Internal Reflection Microscopy (HoloTIRM) to study the influence of the spontaneous polarization of ferroelectric lithium niobate (LN) on the adhesion properties of fibroblast cells. The selective illumination of a very thin region directly above the substrate, achieved by Total Internal Reflection, provides high-contrast images of the contact regions. Holographic recording, on the other hand, allows for label-free quantitative phase imaging of the contact areas between cells and LN. Phase signal is more sensitive in the first 100nm and, thus more reliable in order to locate focal contacts. This work shows that cells adhering on negatively polarized LN present a significant increase of the contact area in comparison with cells adhering on the positively polarized LN substrate, as well as an intensification of contact vicinity. This confirms the potential of LN as a platform for investigating the role of charges on cellular processes. The similarity of cell adhesion behavior on negatively polarized LN and glass control also confirms the possibility to use LN as an active substrate without impairing cell behavior.

  1. Low energy electron imaging of domains and domain walls in magnesium-doped lithium niobate.

    Science.gov (United States)

    Nataf, G F; Grysan, P; Guennou, M; Kreisel, J; Martinotti, D; Rountree, C L; Mathieu, C; Barrett, N

    2016-09-09

    The understanding of domain structures, specifically domain walls, currently attracts a significant attention in the field of (multi)-ferroic materials. In this article, we analyze contrast formation in full field electron microscopy applied to domains and domain walls in the uniaxial ferroelectric lithium niobate, which presents a large 3.8 eV band gap and for which conductive domain walls have been reported. We show that the transition from Mirror Electron Microscopy (MEM - electrons reflected) to Low Energy Electron Microscopy (LEEM - electrons backscattered) gives rise to a robust contrast between domains with upwards (Pup) and downwards (Pdown) polarization, and provides a measure of the difference in surface potential between the domains. We demonstrate that out-of-focus conditions of imaging produce contrast inversion, due to image distortion induced by charged surfaces, and also carry information on the polarization direction in the domains. Finally, we show that the intensity profile at domain walls provides experimental evidence for a local stray, lateral electric field.

  2. Formation of nanodomain structures during polarization reversal in congruent lithium niobate implanted with Ar ions.

    Science.gov (United States)

    Shur, Vladimir Ya; Alikin, Denis O; Ievlev, Anton V; Dolbilov, Mikhail A; Sarmanova, Marina F; Gavrilov, Nikolay V

    2012-09-01

    We present the experimental study of the formation of self-similar nanodomain structures during polarization reversal in single-crystalline congruent lithium niobate (CLN) implanted by Ar ions. The formed dense surface nanodomain structure with charged domain walls differs drastically from the growth of the hexagonal domains in unimplanted CLN. The lack of wall shape stability during sideways domain wall motion was revealed. The analysis of the domain structure images in the bulk, obtained by Raman confocal microscopy, revealed the main stages of the domain structure evolution starting at unimplanted polar surface and consisting of nanodomain chain elongation, merging of isolated domains, and domain widening. The switching current data has been fitted by modification of Kolmogorov-Avrami formula for switching in a linearly increasing field. The observed experimental facts have been attributed to formation of an amorphous thin surface layer and increase of the bulk conductivity resulting from oxygen out-diffusion under radiation heating in vacuum during ion implantation. The formation of the experimentally obtained abnormal domain shapes has been explained while taking into account the step generation at the domain wall in the bulk during switching in a low electric field.

  3. X-ray absorption spectroscopy investigation of structurally modified lithium niobate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Vitova, Tonya

    2008-02-15

    The type and concentration of impurity centers in different valence states are crucial for tuning the photorefractive properties of doped Lithium Niobate (LN) crystals. X-ray Absorption Spectroscopy (XAS) is an appropriate tool for studying the local structure of impurity centers. XAS combined with absorption in UV/VIS/IR and High Resolution X-ray Emission Spectroscopy (HRXES) provide information about the valence state of the dopant ions in as-grown, reduced or oxidized doped LN crystals. Cu (Cu{sup 1+} and Cu{sup 2+}) and Fe (Fe{sup 2+} and Fe{sup 3+}) atoms are found in two different valence states, whereas there are indications for a third Mn valency, in addition to Mn{sup 2+} and Mn{sup 3+} in manganese-doped LN crystals. One of the charge compensation mechanisms during reduction of copper- doped LN crystals is outgassing of oxygen atoms. Cu ions in the reduced crystals have at least two different site symmetries: twofold (Cu{sup 1+}) and sixfold (Cu{sup 2+}) coordinated by O atoms. Fe and Mn atoms are coordinated by six O atoms. Cu and Fe ions are found to occupy only Li sites, whereas Mn ions are also incorporated into Li and Nb sites. The refractive index change in LN crystals irradiated with {sup 3}He{sup 2+} ions is caused by structurally disordered centers, where Nb atoms are displaced from normal crystallographic sites and Li or/and O vacancies are present. (orig.)

  4. Effect of chemical pressure on competition and cooperation between polar and antiferrodistortive distortions in sodium niobate

    Science.gov (United States)

    Jauhari, Mrinal; Mishra, S. K.; Mittal, R.; Sastry, P. U.; Chaplot, S. L.

    2017-12-01

    We present results obtained from a combination of dielectric and x-ray diffraction measurements for compositional design of (1 -x )NaNb O3-x BaTi O3(NNBT x ) , which can induce interferroelectric phase transitions. Anomalies are observed in dielectric measurements performed for various compositions at 300 K, as well as at different temperatures for NNBT03. We observed the appearance(disappearance) of the superlattice reflections along with change in the intensities of the main perovskite peaks in the powder x-ray diffraction data, which provide clear evidences for structural phase transitions with composition and temperature. We found that increasing the concentration of BaTi O3 leads to the suppression of out-of-phase rotation of octahedra and an increment in tetragonality (c /a ratio), which promotes the polar mode at room temperature. The temperature-dependent powder diffraction study shows that the ferroelectric rhombohedral phase of pure sodium niobate gets suppressed for the composition x =0.03 , and the monoclinic phase C c gets stabilized at low temperature. The monoclinic phase is believed to provide for a flexible polarization rotation and is considered to be directly linked to the high-performance piezoelectricity in materials due to presence of more easy axes for spontaneous polarizations than the rhombohedral phase.

  5. Optical parametric generation at extremely low pump irradiance in a long periodically poled lithium niobate

    Science.gov (United States)

    Acco, Shy; Blau, Pinhas; Pearl, Shaul; Arie, Ady

    2007-02-01

    Optical parametric generator (OPG) is a very attractive optical down-conversion configuration since it is a single pass process and no cavity mirror's alignment is required. Thus the system configuration is much more simple and robust. Traditionally, OPG processes were demonstrated using a pump source with a pulse length of the order of picoseconds or less. This is because GW/cm2 order of magnitude pump irradiance was required to excite an OPG process, and such irradiance in nanosecond long pulses commonly damages the non-linear crystal. The introduction of periodically poled crystals with high non-linear coefficients has significantly lowered the threshold for parametric processes. This progress in non-linear crystals enables exciting OPG processes at less than 100MW/cm2 irradiance, using nanoseconds long pulses from Q-switched lasers. We present an OPG with a threshold of less than 10 MW/cm2 using an 80 mm long Periodically Poled Lithium Niobate (PPLN) non-linear crystal. High signal conversion efficiency and high power were obtained at 25 nanosecond pulse length, 10 kHz repetition rate pumping without damaging the crystal. Theoretical approaches for explaining this OPG regime are discussed.

  6. Nanotechnology in lithium niobate for integrated optic frequency conversion in the UV

    Science.gov (United States)

    Busacca, Alessandro C.; Santini, Claudia; Oliveri, Luigi; Riva-Sanseverino, Stefano; Parisi, Antonino; Cino, Alfonso C.; Assanto, Gaetano

    2017-11-01

    In the domain of Earth Explorer satellites nanoengineered nonlinear crystals can optimize UV tunable solid-state laser converters. Lightweight sources can be based on Lithium Niobate (LN) domain engineering by electric field poling and guided wave interactions. In this Communication we report the preliminary experimental results and the very first demonstration of UltraViolet second-harmonic generation by first-order quasi-phase-matching in a surface-periodically-poled proton-exchanged LN waveguide. The pump source was a Ti-Sapphire laser with a tunability range of 700- 980 nm and a 40 GHz linewidth. We have measured UV continuous-wave light at 390 nm by means of a lock-in amplifier and of a photodiode with enhanced response in the UV. Measured conversion efficiency was about 1%W-1cm-2. QPM experiments show good agreement with theory and pave the way for a future implementation of the technique in materials less prone to photorefractive damage and wider transparency in the UV, such as Lithium Tantalate.

  7. Study on the Effect of Pt Intercalation into Layered Niobate Perovskite for Photocatalytic Behavior.

    Science.gov (United States)

    Xu, Nan; Takei, Takahiro; Miura, Akira; Kumada, Nobuhiro; Katsumata, Ken-ichi; Matsushita, Nobuhiro; Okada, Kiyoshi

    2015-07-14

    A novel photocatalyst consisting of an intercalated perovskite H(1-2x)Pt(x)LaNb2O7 was fabricated by ion exchange. Synchrotron X-ray diffraction and X-ray photoelectron spectroscopy results confirmed that Pt(2+) exists within the interlayer space of the layered perovskite. H(1-2x)Pt(x)LaNb2O7 composed of layered niobate perovskite and intercalated Pt(2+) completely degraded a 20 ppm phenol solution in 3 h under irradiation by Xe light, which exhibits photocatalytic activity superior to those of RbLaNb2O7, Pt-deposited RbLaNb2O7, and HLaNb2O7. From first-principles density functional theory simulation, high photocatalytic activity of H(1-2x)Pt(x)LaNb2O7 is attributed to the emergence of a new O 2p-Pt 5d hybridized band on top of the valence band.

  8. Quantitative analysis of exfoliation and aspect ratio of calcium niobate platelets.

    Science.gov (United States)

    Gao, Hongsheng; Shori, Shailesh; Chen, Xiaoming; zur Loye, Hans-Conrad; Ploehn, Harry J

    2013-02-15

    This work employs tapping-mode AFM and dynamic light scattering (DLS) to investigate the effects of suspension composition (alkylammonium cation type, concentration) on the degree of exfoliation of a layered perovskite, calcium niobate (HCa(2)Nb(3)O(10), denoted as CNP). It is well known that in aqueous suspensions, tetrabutylammonium (TBA) cations intercalate CNP's layered structure, producing exfoliated platelets. This work shows that tetramethylammonium and tetraethylammonium cations do not produce significant levels of CNP exfoliation. However, TBA leads to complete exfoliation of CNP (>95%) in suspensions prepared with TBA:CNP ratios greater than 1:1. TGA and XRD data indicate that TBA uptake is limited by steric packing constraints. After depositing TBA-CNP platelets on mica surfaces for AFM imaging, quantitative image analysis provides the degree of exfoliation and distributions of platelet thickness, lateral size, and aspect ratio. The aspect ratio of TBA-CNP platelets has a lognormal distribution. Sedimentation of TBA-CNP suspensions under unit gravity removes unexfoliated particles from suspension, and centrifugation leads to differential sedimentation. The lateral size and aspect ratio of residual suspended TBA-CNP platelets decrease with increasing centrifugation speed. For all fractions of TBA-CNP platelets, the number-average lateral size from AFM agrees remarkably well with the effective spherical particle diameter measured by DLS. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Domain patterning by electron beam of MgO doped lithium niobate covered by resist

    Science.gov (United States)

    Shur, V. Ya.; Chezganov, D. S.; Akhmatkhanov, A. R.; Kuznetsov, D. K.

    2015-06-01

    Periodical domain structuring by focused electron beam irradiation of MgO-doped lithium niobate (MgOCLN) single crystalline plate covered by resist layer was studied both experimentally and by computer simulation. The dependences of domain size on the charge dose and distance between isolated domains were measured. It has been shown that the quality of periodical domain pattern depends on the thickness of resist layer and electron energy. The experimentally obtained periodic domain structures have been divided into four types. The irradiation parameters for the most uniform patterning were obtained experimentally. It was shown by computer simulation that the space charge slightly touching the crystal surface produced the maximum value of electric field at the resist/LN interface thus resulting in the best pattern quality. The obtained knowledge allowed us to optimize the poling process and to make the periodical domain patterns in 1-mm-thick wafers with an area up to 1 × 5 mm2 and a period of 6.89 μm for green light second harmonic generation. Spatial distribution of the efficiency of light frequency conversion confirmed the high homogeneity of the tailored domain patterns.

  10. Optical homogeneity, defects, and photorefractive properties of stoichiometric, congruent, and zinc-doped lithium niobate crystals

    Science.gov (United States)

    Sidorov, N. V.; Yanichev, A. A.; Palatnikov, M. N.; Gabain, A. A.; Pikoul, O. Yu.

    2014-07-01

    Using the laser-conoscopy method, the photorefractive light-scattering method, and the Raman light-scattering method, we have studied the structural and optical homogeneities and photorefractive properties of (i) stoichiometric lithium niobate crystals (LiNbO3(stoich)), which were grown from a melt with 58.6 mol % of Li2O; (ii) congruent crystals (LiNbO3(congr)); and (iii) congruent crystals that were doped with Zn2+ cations (LiNbO3:Zn; [Zn] = 0.03-1.59 mol %). We have shown that the speckle-structure of the photorefractive light scattering in all the crystals is three-layer. The shapes of the second and third layers repeat in general the shape of the first layer. We have shown that the differences that are observed between the Raman spectra, the photorefractive light scattering, and the conoscopic patterns of the examined crystals are caused by the fact that defects are distributed inhomogeneously over the volume of these crystals and that Zn2+ cations are incorporated inhomogeneously into the lattice. This leads to the appearance of local changes in the elastic characteristics of the crystal and to the appearance of mechanical stresses, which locally change the optical indicatrix and, correspondingly, the conoscopic pattern and the Raman spectrum.

  11. Domain patterning by electron beam of MgO doped lithium niobate covered by resist

    Energy Technology Data Exchange (ETDEWEB)

    Shur, V. Ya., E-mail: vladimir.shur@urfu.ru; Chezganov, D. S.; Akhmatkhanov, A. R. [Institute of Natural Sciences, Ural Federal University, 620000 Ekaterinburg (Russian Federation); Labfer Ltd., 620014 Ekaterinburg (Russian Federation); Kuznetsov, D. K. [Institute of Natural Sciences, Ural Federal University, 620000 Ekaterinburg (Russian Federation)

    2015-06-08

    Periodical domain structuring by focused electron beam irradiation of MgO-doped lithium niobate (MgOCLN) single crystalline plate covered by resist layer was studied both experimentally and by computer simulation. The dependences of domain size on the charge dose and distance between isolated domains were measured. It has been shown that the quality of periodical domain pattern depends on the thickness of resist layer and electron energy. The experimentally obtained periodic domain structures have been divided into four types. The irradiation parameters for the most uniform patterning were obtained experimentally. It was shown by computer simulation that the space charge slightly touching the crystal surface produced the maximum value of electric field at the resist/LN interface thus resulting in the best pattern quality. The obtained knowledge allowed us to optimize the poling process and to make the periodical domain patterns in 1-mm-thick wafers with an area up to 1 × 5 mm{sup 2} and a period of 6.89 μm for green light second harmonic generation. Spatial distribution of the efficiency of light frequency conversion confirmed the high homogeneity of the tailored domain patterns.

  12. VKCDB: Voltage-gated potassium channel database

    Directory of Open Access Journals (Sweden)

    Gallin Warren J

    2004-01-01

    Full Text Available Abstract Background The family of voltage-gated potassium channels comprises a functionally diverse group of membrane proteins. They help maintain and regulate the potassium ion-based component of the membrane potential and are thus central to many critical physiological processes. VKCDB (Voltage-gated potassium [K] Channel DataBase is a database of structural and functional data on these channels. It is designed as a resource for research on the molecular basis of voltage-gated potassium channel function. Description Voltage-gated potassium channel sequences were identified by using BLASTP to search GENBANK and SWISSPROT. Annotations for all voltage-gated potassium channels were selectively parsed and integrated into VKCDB. Electrophysiological and pharmacological data for the channels were collected from published journal articles. Transmembrane domain predictions by TMHMM and PHD are included for each VKCDB entry. Multiple sequence alignments of conserved domains of channels of the four Kv families and the KCNQ family are also included. Currently VKCDB contains 346 channel entries. It can be browsed and searched using a set of functionally relevant categories. Protein sequences can also be searched using a local BLAST engine. Conclusions VKCDB is a resource for comparative studies of voltage-gated potassium channels. The methods used to construct VKCDB are general; they can be used to create specialized databases for other protein families. VKCDB is accessible at http://vkcdb.biology.ualberta.ca.

  13. Effect of the structure and mechanical properties of the near-surface layer of lithium niobate single crystals on the manufacture of integrated optic circuits

    Science.gov (United States)

    Sosunov, A. V.; Ponomarev, R. S.; Yur'ev, V. A.; Volyntsev, A. B.

    2017-01-01

    This paper shows that the near-surface layer of a lithium niobate single layer 15 μm in depth is essentially different from the rest of the volume of the material from the standpoint of composition, structure, and mechanical properties. The pointed out differences are due to the effect of cutting, polishing, and smoothing of the lithium niobate plates, which increase the density of point defects and dislocations. The increasing density of the structural defects leads to uncontrollable changes in the conditions of the formations of waveguides and the drifting of characteristics of integrated optical circuits. The results obtained are very important for the manufacture of lithium niobate based integrated optical circuits.

  14. Serum potassium concentrations: Importance of normokalaemia.

    Science.gov (United States)

    Heras, Manuel; Fernández-Reyes, María José

    2017-06-21

    Abnormalities in potassium concentrations are associated with morbidity and mortality. In recent years it has been considered that small variations in serum potassium concentrations within normal intervals may also be associated with mortality. Strategies for achieving normokalaemia include dietary measures, limiting the use of potassium retaining drugs, and use of conventional cation exchange resins (calcium/sodium polystyrene sulfonate) and/or the new non-absorbed cation exchange polymer (patiromer). Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

  15. Fabrication of supported Ca-doped lanthanum niobate electrolyte layer and NiO containing anode functional layer by electrophoretic deposition

    DEFF Research Database (Denmark)

    Bozza, Francesco; Bonanos, Nikolaos

    2012-01-01

    The technique of electrophoretic deposition (EPD) has been applied for the preparation of a dense calcium-doped lanthanum niobate electrolyte film. La0.995Ca0.005NbO4 (LCN) powder was suspended in a solution of acetylacetone, iodine and water. The effects of suspension composition and deposition...... conditions were analyzed in order to identify a suitable set of EPD process parameters. The powders were deposited on a composite substrate of LCN, NiO, binder and graphite. A dense 8 μm film of lanthanum niobate supported on a porous substrate was obtained after sintering at 1200 °C. The technique was found...

  16. Qualitative Carbohydrate Analysis using Alkaline Potassium ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 3. Qualitative Carbohydrate Analysis using Alkaline Potassium Ferricyanide. Sangeeta Pandita Saral Baweja. Classroom Volume 21 Issue 3 March 2016 pp 285-288 ...

  17. Ultraviolet laser-induced poling inhibition produces bulk domains in MgO-doped lithium niobate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Boes, Andreas, E-mail: s3363819@student.rmit.edu.au; Steigerwald, Hendrik; Sivan, Vijay; Mitchell, Arnan [School of Electrical and Computer Engineering, RMIT University, Melbourne, Victoria 3001 (Australia); ARC Center for Ultra-high Bandwidth Devices for Optical Systems (CUDOS), RMIT University, Melbourne, Victoria 3001 (Australia); Yudistira, Didit [School of Electrical and Computer Engineering, RMIT University, Melbourne, Victoria 3001 (Australia); Wade, Scott [Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Victoria 3122 (Australia); Mailis, Sakellaris [Optoelectronics Research Centre, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Soergel, Elisabeth [Institute of Physics, University of Bonn, Wegelerstr. 8, 53115 Bonn (Germany)

    2014-09-01

    We report the realization of high-resolution bulk domains achieved using a shallow, structured, domain inverted surface template obtained by UV laser-induced poling inhibition in MgO-doped lithium niobate. The quality of the obtained bulk domains is compared to those of the template and their application for second harmonic generation is demonstrated. The present method enables domain structures with a period length as small as 3 μm to be achieved. Furthermore, we propose a potential physical mechanism that leads to the transformation of the surface template into bulk domains.

  18. Design of reversible sequential circuits using electro-optic effect of lithium-niobate-based Mach-Zehnder interferometers

    Science.gov (United States)

    Kumar, Santosh; Chauhan, Chanderkanta; Bedi, Amna

    2016-12-01

    In recent years, it has been shown that reversible logic can play an important role in power optimization for computer design. The various reversible logic gates such as Feynman, Fredkin, Peres, and Toffoli gates have been discussed by researchers, but very little work has been done on reversible sequential circuits. Design of reversible sequential circuits using lithium-niobate-based Mach-Zehnder interferometers is proposed. Here, flip-flops are designed with the help of basic reversible logic gates such as Feynman, Fredkin, and Peres gates. Theoretical descriptions along with mathematical formulation of the devices are provided. The devices are also analyzed through finite difference-beam propagation method and MATLAB® simulation.

  19. Heterogeneous integration of lithium niobate and silicon nitride waveguides for wafer-scale photonic integrated circuits on silicon.

    Science.gov (United States)

    Chang, Lin; Pfeiffer, Martin H P; Volet, Nicolas; Zervas, Michael; Peters, Jon D; Manganelli, Costanza L; Stanton, Eric J; Li, Yifei; Kippenberg, Tobias J; Bowers, John E

    2017-02-15

    An ideal photonic integrated circuit for nonlinear photonic applications requires high optical nonlinearities and low loss. This work demonstrates a heterogeneous platform by bonding lithium niobate (LN) thin films onto a silicon nitride (Si3N4) waveguide layer on silicon. It not only provides large second- and third-order nonlinear coefficients, but also shows low propagation loss in both the Si3N4 and the LN-Si3N4 waveguides. The tapers enable low-loss-mode transitions between these two waveguides. This platform is essential for various on-chip applications, e.g., modulators, frequency conversions, and quantum communications.

  20. Reduced pulse energy for frequency comb offset stabilization with a dual-pitch periodically poled lithium niobate ridge waveguide

    Science.gov (United States)

    Hitachi, K.; Hara, K.; Tadanaga, O.; Ishizawa, A.; Nishikawa, T.; Gotoh, H.

    2017-06-01

    The pulse energy for stabilizing the carrier-envelop offset frequency of an Er-doped fiber laser was reduced by a dual-pitch (DP-) periodically poled lithium niobate (PPLN) ridge waveguide implemented in a 2f-to-3f self-referencing interferometer (SRI). The pulse energy requirement was less than half that for a single-pitch PPLN ridge waveguide implemented in an f-to-2f SRI. We also found that environmental noise could be reduced by adjusting the pulse energy for frequency stabilization with the DP-PPLN ridge waveguide, as estimated from the phase noise of an out-of-loop interferometer.

  1. Noise Analysis of Second-Harmonic Generation in Undoped and MgO-Doped Periodically Poled Lithium Niobate

    OpenAIRE

    Yong Wang; Jorge Fonseca-Campos; Wan-guo Liang; Chang-Qing Xu; Ignacio Vargas-Baca

    2008-01-01

    Noise characteristics of second-harmonic generation (SHG) in periodically poled lithium niobate (PPLN) using the quasiphase matching (QPM) technique are analyzed experimentally. In the experiment, a0.78 μm second-harmonic (SH) wave was generated when a 1.56 μm fundamental wave passed through a PPLN crystal (bulk or waveguide). The time-domain and frequency-domain noise characteristics of the fundamental and SH waves were analyzed. By using the pump-probe method, the noise characteristics of S...

  2. Design of 4 to 2 line encoder using lithium niobate based Mach Zehnder Interferometers for high speed communication

    Science.gov (United States)

    Pal, Amrindra; Kumar, Santosh; Sharma, Sandeep; Raghuwanshi, Sanjeev K.

    2016-04-01

    Encoder is a device that allows placing digital information from many inputs to many outputs. Any application of combinational logic circuit can be implemented by using encoder and external gates. In this paper, 4 to 2 line encoder is proposed using electro-optic effect inside lithium-niobate based Mach-Zehnder interferometers (MZIs). The MZI structures have powerful capability to switching an optical input signal to a desired output port. The paper constitutes a mathematical description of the proposed device and thereafter simulation using MATLAB. The study is verified using beam propagation method (BPM).

  3. Ultraviolet laser-induced poling inhibition produces bulk domains in MgO-doped lithium niobate crystals

    Science.gov (United States)

    Boes, Andreas; Steigerwald, Hendrik; Yudistira, Didit; Sivan, Vijay; Wade, Scott; Mailis, Sakellaris; Soergel, Elisabeth; Mitchell, Arnan

    2014-09-01

    We report the realization of high-resolution bulk domains achieved using a shallow, structured, domain inverted surface template obtained by UV laser-induced poling inhibition in MgO-doped lithium niobate. The quality of the obtained bulk domains is compared to those of the template and their application for second harmonic generation is demonstrated. The present method enables domain structures with a period length as small as 3 μm to be achieved. Furthermore, we propose a potential physical mechanism that leads to the transformation of the surface template into bulk domains.

  4. Direct deposition of trivalent rhodium hydroxide nanoparticles onto a semiconducting layered calcium niobate for photocatalytic hydrogen evolution.

    Science.gov (United States)

    Hata, Hideo; Kobayashi, Yoji; Bojan, Vince; Youngblood, W Justin; Mallouk, Thomas E

    2008-03-01

    Well-dispersed Rh(OH)3 nanoparticles were deposited in the interlayer galleries of a Dion-Jacobson type layered perovskite (ACa2Nb3O10: A=H or K). X-ray photoelectron spectra and zeta potential measurements suggest covalent bonding (Rh-O-Nb) between the nanoparticles and the niobate sheets. After calcination of Rh(OH)3/KCa2Nb3O10 at 350 degrees C in air, interlayer Rh(OH)3 nanoparticles were transformed to Rh2O3 and showed higher photocatalytic activity for hydrogen evolution using methanol as a sacrificial electron donor.

  5. Connexin 43 impacts on mitochondrial potassium uptake

    Directory of Open Access Journals (Sweden)

    Kerstin eBoengler

    2013-06-01

    Full Text Available In cardiomyocytes, connexin 43 (Cx43 forms gap junctions and unopposed hemichannels at the plasma membrane, but the protein is also present at the inner membrane of subsarcolemmal mitochondria. Both inhibition and genetic ablation of Cx43 reduce ADP-stimulated complex 1 respiration. Since mitochondrial potassium influx impacts on oxygen consumption, we investigated whether or not inhibition or ablation of mitochondrial Cx43 alters mitochondrial potassium uptake.Subsarcolemmal mitochondria were isolated from rat left ventricular (LV myocardium and loaded with the potassium-sensitive dye PBFI. Intramitochondrial potassium was replaced by TEA (tetraethylammonium. Mitochondria were incubated under control conditions or treated with 250 µM Gap19, a peptide that specifically inhibits Cx43-dependent hemichannels at plasma membranes. Subsequently, 140 mM KCl was added and the slope of the increase in PBFI fluorescence over time was calculated. The slope of the PBFI fluorescence of the control mitochondria was set to 100%. In the presence of Gap19, the mitochondrial potassium influx was reduced from 100±11.6 % in control mitochondria to 65.5±10.7 % (n=6, p<0.05. In addition to the pharmacological inhibition of Cx43, potassium influx was studied in mitochondria isolated from conditional Cx43 knockout mice. Here, the ablation of Cx43 was achieved by the injection of 4-hydroxytamoxifen (Cx43Cre-ER(T/fl + 4-OHT. The mitochondria of the Cx43Cre-ER(T/fl + 4-OHT mice contained 3±1% Cx43 (n=6 of that in control mitochondria (100±11%, n=8, p<0.05. The ablation of Cx43 (n=5 reduced the velocity of the potassium influx from 100±11.2 % in control mitochondria (n=9 to 66.6±5.5 % (p<0.05.Taken together, our data indicate that both pharmacological inhibition and genetic ablation of Cx43 reduce mitochondrial potassium influx.

  6. The Ketogenic Diet and Potassium Channel Function

    Science.gov (United States)

    2015-11-01

    1 AWARD NUMBER: W81XWH-13-1-0463 TITLE: The Ketogenic Diet and Potassium Channel Function PRINCIPAL INVESTIGATOR: Dr. Geoffrey Murphy...NUMBER The Ketogenic Diet and Potassium Channel Function 5b. GRANT NUMBER W81XWH-13-1-0463 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Geoffrey Murphy...The overall objective of this Discovery Award was to explore the hypothesis the ketogenic diet (KD) regulates neuronal excitability by influencing

  7. 21 CFR 181.34 - Sodium nitrite and potassium nitrite.

    Science.gov (United States)

    2010-04-01

    ... fixatives and preservative agents, with or without sodium or potassium nitrate, in the curing of red meat... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrite and potassium nitrite. 181.34...-Sanctioned Food Ingredients § 181.34 Sodium nitrite and potassium nitrite. Sodium nitrite and potassium...

  8. Potassium chloride production by microcline chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Orosco, Pablo, E-mail: porosco@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, San Luis (Argentina); Ruiz, María del Carmen [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina)

    2015-08-10

    Highlights: • Use of chlorination for the KCl production. • The reagents used were microcline, hydromagnesite and chlorine. • Isothermal and non-isothermal assays were performed in Cl{sub 2}–N{sub 2} mixture. • The chlorination generated KCl at 700 °C. • The chlorination products promote KCl formation. - Abstract: The potassium chloride is one of the most important fertilizers used in agriculture. The current demand of this salt makes interesting the study of potassium chloride production from unconventional potassium resources. In this work the potassium chloride production by chlorination of microcline was investigated. The starting reagents were microcline, hydromagnesite and chlorine. Non-isothermal and isothermal chlorination assays were carried out in a thermogravimetric device adapted to work in corrosive atmospheres. The temperature effect on potassium extraction and the phase transformations produced during chlorination of microcline were studied. The reagents and reaction products were analyzed by X-ray fluorescence (XRF) and X-ray diffraction (XRD). The experimental results indicated that by chlorination of microcline an important extraction of potassium in the temperature range from 800 to 900 °C was produced. Moreover, at 800 °C the forsterite, enstatite and magnesium aluminate spinel phases were generated.

  9. Nanocrystallization of ferroelectric strontium bismuth vanadium niobate in lithium tetraborate glasses.

    Science.gov (United States)

    Venkataraman, B Harihara; Varma, K B R

    2005-12-01

    Transparent glass samples in (100-3x) (Li2O-2B2O3)-x(SrO-Bi2O3-0.7Nb2O5-0.3V2O5) (10 melt-quenching technique. The as-quenched samples, of all the compositions under study have been confirmed to be amorphous, by X-ray powder diffraction (XRD) studies. Differential thermal analysis (DTA) was employed to confirm the glassy nature of the as-quenched glasses. Glass composites comprising vanadium doped strontium bismuth niobate nanocrystallites were obtained by controlled heat-treatment of the as-quenched glasses at 783 K for 6 h. Perovskite SrBi2(Nb0.7VO3)2O9-delta phase formation was found to be preceded by an intermediate fluorite phase which was established via XRD and transmission electron microscopy (TEM). The dielectric constants (epsilonr) of the as-quenched glasses as well as the glass nanocrystal composites decreased with increase in frequency (100 Hz-10 kHz) at 300 K. Interestingly, the dielectric constant of the glass nanocrystal composite (heat-treated at 783 K/6 h) undergoes a maximum in the vicinity of the crystallization temperature of the host glass (Li2B4O7) reaching an anomalously high value (approximately 10(6)) at 800 K. Different dielectric mixture formulae were employed to rationalize the dielectric properties of the glass nanocrystal composite. The optical transmission properties of these glass nanocrystal composites were found to have strong compositional dependence.

  10. Photo-induced Nanopattern Formation on Polarity Patterned Lithium Niobate with ZnO-Modified Surfaces

    Science.gov (United States)

    Kaur, Manpuneet; Wang, Xingye; Eller, Brianna; Nemanich, Robert

    2015-03-01

    This research is focused on modifying the surface of polarity patterned lithium niobate (PPLN) templates with ultra thin layers of ZnO. Photo-induced nanopattern formation is employed to discern the effects of thin ZnO on PPLN. The spontaneous polarization of ZnO is intended to be used to enhance the photo-induced transport of electrons to the surface to reduce Ag + to Ag nanoparticles. The ZnO thin films were deposited by plasma enhanced atomic layer deposition (PEALD) at 150 C with 0.2 nm/cycle. Photo-induced Ag nanopatterns were deposited on bare PPLN and 1, 2, 3 and 10 nm ZnO-PPLN heterostructures, immersed on an aqueous AgNO3 solution and illumination with 254 nm UV light. The photo-induced deposition of 1nm ZnO/PPLN results in enhanced Ag nanoparticle formation at domain boundaries. The positive domain selectivity is not observed on 2nm ZnO/PPLN templates, and the deposition becomes the same on both domains. The nanoparticle patterns were not evident for ZnO films thicker than 3nm. The amorphous structure of thick ZnO on PPLN tends to reduce the effect of the ZnO polarization. The effect of polarity patterned thin PEALD ZnO films is discussed to understand photo-induced electron transfer and AgNO3 reduction on ZnO-PPLN heterostructures. This research is supported by the NSF through Grant DMR-1206935.

  11. Synthesis of spherical mesoporous titania modified iron-niobate nanoclusters for photocatalytic reduction of 4-nitrophenol

    Directory of Open Access Journals (Sweden)

    Tanmay K. Ghorai

    2015-04-01

    Full Text Available Spherical mesoporous titania modified iron-niobate nanoclusters FNT1 [FexNbxTi1−2xO2−x/2 (x = 0.01], with relatively small particle size 10 ± 2 nm and SBET 145 m2 g−1 were prepared using a sol–gel method, from the reaction of titanium and niobium tartrate with triethanol amine and ferric nitrate solution. HRTEM of FNT1 shows coexistence of porous mesostructure and high symmetric order of crystallinity in the nanoparticles. The mesopore size is in the range of 4–5 nm and the lattice fringes of 0.37 nm is observed in the mesopore walls which correspond to the d-spacing between adjacent (101 crystallographic planes of FNT1 phase. This is supported by XRD studies. In the presence of UV light, FNT1 (0.1 g/50 mL reduces the 4-nitrophenol (4-NP (0.0139 g L−1 to 4-aminophenol by using NaBH4 (0.054 g L−1 in contrast to pure TiO2 and other composites of FexNbxTi1−2xO2−x/2 photocatalysts. The 4-NP is reduced to 4-aminophenol within 10 min in the presence of FNT1 and UV light, but in the absence of the catalysts, it takes approximately 82 min. The catalytic activity of FNT1 is enhanced significantly in the presence of UV light compared to the absence of UV light. We observed that the catalytic activity of the prepared catalyst also depends on crystal size, particle morphology and particle porosity, and dopant concentrations.

  12. Localized devitrifiation in Er{sup 3+}-doped strontium barium niobate glass by laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Haro-Gonzalez, P.; Martin, I.R.; Lahoz, F.; Gonzalez-Perez, S. [Universidad de La Laguna, Departamento de Fisica Fundamental, Electronica y Sistemas, La Laguna, Tenerife (Spain); Capuj, N.E. [Universidad de La Laguna, Departamento de Fisica Basica, La Laguna, Tenerife (Spain); Jaque, D. [Universidad Autonoma de Madrid, Departamento de Fisica de Materiales, Madrid (Spain)

    2008-12-15

    Localized devitrifiation in strontium barium niobate glass doped with Er{sup 3+} under laser irradiation has been carried out. The samples of this study have been fabricated by the melt quenching method and doped with 5% mol of Er{sup 3+}. A 1.5-W cw Ar laser was focused on the sample to obtain devitrifiation of the glass. Evidence of the changes induced by the Ar laser has been observed through the analysis of the photoluminescence of the Er{sup 3+} ions. The transitions corresponding to {sup 2}H{sub 11/2}{yields}{sup 4}I{sub 15/2}, {sup 4}S{sub 3/2}{yields}{sup 4}I{sub 15/2} and {sup 4}F{sub 9/2}{yields}{sup 4}I{sub 15/2} have been studied to analyze structure changes. Microluminescence measurements have been carried out to spatially select positions inside and outside the irradiated area. We have observed changes in the emission bands corresponding to these transitions. The emission bands from Er{sup 3+} ions in the irradiated zone show a resolved structure while they are broadened outside that area. These changes in the optical properties of the Er{sup 3+} ions indicate that the Ar-laser irradiation has produced a change in the local structure of the material. These results show that a localized devitrifiation has been produced after the laser action and the transition from glass to glass ceramic has been completed. (orig.)

  13. Interface modulated currents in periodically proton exchanged Mg doped lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Neumayer, Sabine M.; Rodriguez, Brian J., E-mail: brian.rodriguez@ucd.ie, E-mail: gallo@kth.se [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4 (Ireland); Manzo, Michele; Gallo, Katia, E-mail: brian.rodriguez@ucd.ie, E-mail: gallo@kth.se [Department of Applied Physics, KTH-Royal Institute of Technology, Roslagstullbacken 21, 10691 Stockholm (Sweden); Kholkin, Andrei L. [Department of Physics and CICECO-Aveiro Institute of Materials, 3810-193 Aveiro, Portugal and Institute of Natural Sciences, Ural Federal University, 620000 Ekaterinburg (Russian Federation)

    2016-03-21

    Conductivity in Mg doped lithium niobate (Mg:LN) plays a key role in the reduction of photorefraction and is therefore widely exploited in optical devices. However, charge transport through Mg:LN and across interfaces such as electrodes also yields potential electronic applications in devices with switchable conductivity states. Furthermore, the introduction of proton exchanged (PE) phases in Mg:LN enhances ionic conductivity, thus providing tailorability of conduction mechanisms and functionality dependent on sample composition. To facilitate the construction and design of such multifunctional electronic devices based on periodically PE Mg:LN or similar ferroelectric semiconductors, fundamental understanding of charge transport in these materials, as well as the impact of internal and external interfaces, is essential. In order to gain insight into polarization and interface dependent conductivity due to band bending, UV illumination, and chemical reactivity, wedge shaped samples consisting of polar oriented Mg:LN and PE phases were investigated using conductive atomic force microscopy. In Mg:LN, three conductivity states (on/off/transient) were observed under UV illumination, controllable by the polarity of the sample and the externally applied electric field. Measurements of currents originating from electrochemical reactions at the metal electrode–PE phase interfaces demonstrate a memresistive and rectifying capability of the PE phase. Furthermore, internal interfaces such as domain walls and Mg:LN–PE phase boundaries were found to play a major role in the accumulation of charge carriers due to polarization gradients, which can lead to increased currents. The insight gained from these findings yield the potential for multifunctional applications such as switchable UV sensitive micro- and nanoelectronic devices and bistable memristors.

  14. Visible quasi-phase-matched harmonic generation by electric-field-poled lithium niobate

    Science.gov (United States)

    Miller, Gregory D.; Batchko, Robert G.; Fejer, Martin M.; Byer, Robert L.

    1996-05-01

    Laser-based displays and illumination systems are applications which can capitalize on the brightness and efficiency of semiconductor lasers, provided that there is a means for converting their output into the visible spectrum. Semiconductor laser manufacturers can adjust their processes to achieve desired wavelengths in several near-infrared bands; an equally agile conversion technology is needed to permit display and illumination system manufacturers to choose visible wavelengths appropriate to their products. Quasi- phasematched second harmonic generation has the potential to convert high-power semiconductor laser output to the visible with 50% optical-to-optical conversion efficiency in a single-pass bulk configuration, using electric-field-poled lithium niobate. Lithographically- defined electrode structures on the positive or negative polar faces of this crystal are used to control the formation of domains under the influence of electric fields applied using those electrode structures. The quality of the resulting domain patterns not only controls the efficiency of quasi-phasematched second harmonic generation, but also controls the degree of resistance to photorefractive damage. We present a model which is used to identify the optimum electrode duty cycle and applied poling field for domain patterning and compare the predicted domain duty cycle with experimental results. We discuss factors which contribute to inhomogeneous domain pattern quality for samples poled under otherwise ideal conditions and our progress in limiting their influence. Finally, we present optical characterization of a 2.4 mm long 500 micrometers thick sample which produced an average second harmonic power of 1.3 W of 532 nm green from a 9 W average power Q-switched 1064 nm Nd:YAG laser in a loose- focus single-pass configuration.

  15. Interface and thickness dependent domain switching and stability in Mg doped lithium niobate

    Science.gov (United States)

    Neumayer, Sabine M.; Ivanov, Ilia N.; Manzo, Michele; Kholkin, Andrei L.; Gallo, Katia; Rodriguez, Brian J.

    2015-12-01

    Controlling ferroelectric switching in Mg doped lithium niobate (Mg:LN) is of fundamental importance for optical device and domain wall electronics applications that require precise domain patterns. Stable ferroelectric switching has been previously observed in undoped LN layers above proton exchanged (PE) phases that exhibit reduced polarization, whereas PE layers have been found to inhibit lateral domain growth. Here, Mg doping, which is known to significantly alter ferroelectric switching properties including coercive field and switching currents, is shown to inhibit domain nucleation and stability in Mg:LN above buried PE phases that allow for precise ferroelectric patterning via domain growth control. Furthermore, piezoresponse force microscopy (PFM) and switching spectroscopy PFM reveal that the voltage at which polarization switches from the "up" to the "down" state increases with increasing thickness in pure Mg:LN, whereas the voltage required for stable back switching to the original "up" state does not exhibit this thickness dependence. This behavior is consistent with the presence of an internal frozen defect field. The inhibition of domain nucleation above PE interfaces, observed in this study, is a phenomenon that occurs in Mg:LN but not in undoped samples and is mainly ascribed to a remaining frozen polarization in the PE phase that opposes polarization reversal. This reduced frozen depolarization field in the PE phase also influences the depolarization field of the Mg:LN layer above due to the presence of uncompensated polarization charge at the PE-Mg:LN boundary. These alterations in internal electric fields within the sample cause long-range lattice distortions in Mg:LN via electromechanical coupling, which were corroborated with complimentary Raman measurements.

  16. Temperature-stable lithium niobate electro-optic Q-switch for improved cold performance

    Science.gov (United States)

    Jundt, Dieter H.

    2014-10-01

    Lithium niobate (LN) is commonly used as an electro optic (EO) Q-switch material in infrared targeting lasers because of its relatively low voltage requirements and low cost compared to other crystals. A common challenge is maintaining good performance at the sub-freezing temperatures often experienced during flight. Dropping to low temperature causes a pyro-electric charge buildup on the optical faces that leads to birefringence non-uniformity and depolarization resulting in poor hold-off and premature lasing. The most common solution has been to use radioactive americium to ionize the air around the crystal and bleed off the charge, but the radioactive material requires handling and disposal procedures that can be problematic. We have developed a superior solution that is now being implemented by multiple defense system suppliers. By applying a low level thermo-chemical reduction to the LN crystal optical faces we induce a small conductivity that allows pyro-charges to dissipate. As the material gets more heavily treated, the capacity to dissipate charges improves, but the corresponding optical absorption also increases, causing insertion loss. Even though typical high gain targeting laser systems can tolerate a few percent of added loss, the thermo-chemical processing needs to be carefully optimized. We describe the results of our process optimization to minimize the insertion loss while still giving effective charge dissipation. Treatment is performed at temperatures below 500°C and a conductivity layer less than 0.5mm in depth is created that is uniform across the optical aperture. Because the conductivity is thermally activated, the charge dissipation is less effective at low temperature, and characterization needs to be performed at cold temperatures. The trade-off between optical insertion loss and potential depolarization due to low temperature operation is discussed and experimental results on the temperature dependence of the dissipation time and the

  17. Thermodynamic properties of potassium oxides

    Energy Technology Data Exchange (ETDEWEB)

    Byker, H.J. (Montana State Univ., Bozeman); Eliezer, I.; Howald, R.C.; Ehlert, T.C.

    1979-09-01

    KO/sub 0/ /sub 5/ has been prepared by the reaction of excess potassium with KNO/sub 3/ in an effusion cell. Observations of the 2KO/sub 0/ /sub 5/ ..-->.. K/sub 2/O(g) equilibrium mass spectrometrically give a new value for the enthalpy of solid KO/sub 0/ /sub 5/, ..delta..H/sub f,298//sup 0/ = -170 +- 5 kJ mol/sup -1/. Observations on KO/sup +/ in the same series of experiments give good estimates for the thermodynamic properties of K/sub 2/O/sub 2/(g). This leads to an improved interpretation of data on the vaporization of KO/sub 0/ /sub 5/-K/sub 2/O/sub 2/ mixtures and solutions. Similarly literature data on the K/sub 2/O/sub 2/-KO/sub 2/ system have been collected and reexamined, leading to the values ..delta..H/sub f,298//sup 0/ = -495.4 kJ mol/sup -1/ and S/sub 298//sup 0/ = 110.1 J mol/sup -1/ K/sup -1/ for K/sub 2/O/sub 2/(s). We have calculated a preliminary phase diagram for the entire region from KO/sub 0/ /sub 5/ to KO/sub 2/, treating the liquid as solutions of O (1) in KO/sub 0/ /sub 5/ (1). Differential thermal analysis data supporting the calculated phase diagram are reported.

  18. Massive hydration-driven swelling of layered perovskite niobate crystals in aqueous solutions of organo-ammonium bases.

    Science.gov (United States)

    Song, Yeji; Iyi, Nobuo; Hoshide, Tatsumasa; Ozawa, Tadashi C; Ebina, Yasuo; Ma, Renzhi; Yamamoto, Shinya; Miyamoto, Nobuyoshi; Sasaki, Takayoshi

    2017-11-08

    Osmotic swelling behaviors in layered perovskite niobate were examined in aqueous solutions containing three types of amine-related agents including quaternary ammonium hydroxides and tertiary aminoethanol. Platelet microcrystals of a protonated layered perovskite niobate, HCa2Nb3O10·1.5H2O, were found to show enormous swelling in the aqueous solutions, which was clearly recognized by the noticeable expansion of the sample volume over 100-fold. Optical microscopy observations revealed that the crystals underwent accordion-like elongation in the layer-stacking direction up to several ten-fold the initial thickness. Small-angle X-ray scattering measurements of swollen samples indicate the expansion of interlayer separation ranging from ∼20 nm to over 100 nm, which is primarily governed by the concentrations of the amine-related agents. The magnitudes of the interlayer separation were comparable to those of the macroscopic swelling. The degree of swelling was progressively suppressed with further increasing concentration, and this suppression trend was related to the amines.

  19. Extracellular potassium inhibits Kv7.1 potassium channels by stabilizing an inactivated state

    DEFF Research Database (Denmark)

    Larsen, Anders Peter; Steffensen, Annette Buur; Grunnet, Morten

    2011-01-01

    Kv7.1 (KCNQ1) channels are regulators of several physiological processes including vasodilatation, repolarization of cardiomyocytes, and control of secretory processes. A number of Kv7.1 pore mutants are sensitive to extracellular potassium. We hypothesized that extracellular potassium also...

  20. Reducing the thermal stress in a heterogeneous material stack for large-area hybrid optical silicon-lithium niobate waveguide micro-chips

    Science.gov (United States)

    Weigel, P. O.; Mookherjea, S.

    2017-04-01

    The bonding of silicon-on-insulator (SOI) to lithium niobate-on-insulator (LNOI) is becoming important for a new category of linear and nonlinear micro-photonic optical devices. In studying the bonding of SOI to LNOI through benzocyclobutene (BCB), a popular interlayer bonding dielectric used in hybrid silicon photonic devices, we use thermal stress calculations to suggest that BCB thickness does not affect thermal stress in this type of structure, and instead, thermal stress can be mitigated satisfactorily by matching the handles of the SOI and LNOI. We bond LNOI with a silicon handle to a silicon chip, remove the handle on the LNOI side, and thermally cycle the bonded stack repeatedly from room temperature up to 300°C and back down without incurring thermal stress cracks, which do appear when using LNOI with a lithium niobate handle, regardless of the BCB thickness. We show that this process can be used to create many hybrid silicon-lithium niobate waveguiding structures on a single patterned SOI chip bonded to a large-area (16 mm × 4.2 mm) lithium niobate film.

  1. Effects of top excision on the potassium accumulation and expression of potassium channel genes in tobacco.

    Science.gov (United States)

    Dai, Xiao Yan; Su, Yi Rong; Wei, Wen Xue; Wu, Jin Shui; Fan, Ye Kuan

    2009-01-01

    The effects of the removal of the shoot apex of tobacco on the relative transcript levels of potassium channel genes, determined by real-time PCR, and on the relationship between the expression of genes encoding potassium channels and potassium concentration, were studied. The results from the study indicated that comparatively more assimilates of photosynthesis were allocated to the apex in control plants than in both decapitated and IAA-treated decapitated plants. By contrast, dry matter in the upper leaves, roots, and stems in both decapitated and IAA-treated plants was significantly increased relative to control plants. The potassium level in whole plants decreased post-decapitation compared with control plants, and so did the potassium concentration in middle and upper leaves, stem, and roots. Expression of NKT1, NtKC1, NTORK1, and NKT2 was inhibited by decapitation in tobacco leaves with a gradual reduction after decapitation, but was induced in roots. The relative expression of NKT1, NTORK1, and NKT2 in tobacco leaves was higher than that in roots, whereas the expression of NtKC1 was higher in roots. The levels of inhibition and induction of NKT1, NtKC1, NTORK1, and NKT2 in leaves and roots, respectively, associated with decapitation were reduced by the application of IAA on the cut surface of the decapitated stem. Further results showed that the level of endogenous auxin IAA in decapitated plants, which dropped in leaves and increased in roots by 140.7% at 14 d compared with the control plant, might be attributed to the change in the expression of potassium channel genes. The results suggest that there is a reciprocal relationship among endogenous auxin IAA, expression of potassium channel genes and potassium accumulation. They further imply that the endogenous IAA probably plays a role in regulating the expression of potassium channel genes, and that variations in expression of these genes affected the accumulation and distribution of potassium in tobacco.

  2. Potassium permanganate ingestion as a suicide attempt

    Directory of Open Access Journals (Sweden)

    Tuba Cimilli Ozturk

    2012-01-01

    Full Text Available Potassium permanganate is a highly corrosive, water-soluble oxidizing antiseptic. A 68- year-old female patient was admitted to our Emergency Department after ingestion of 3 tablets of 250 mg potassium permanganate as a suicide attempt. The physical exam revealed brown stained lesions in the oropharynx. Emergency endoscopy was performed by the gastroenterologist after the third hour of ingestion. Emergency endoscopy revealed multiple superficial (Grade I-II lesions on the esophagus and cardia, which were considered secondary to the caustic substance. The mainstay in the treatment of potassium permanganate is supportive and the immediate priority is to secure the airway. Emergency endoscopy is an important tool used to evaluate the location and severity of injury to the esophagus, stomach and duodenum after caustic ingestion. Patients with signs and symptoms of intentional ingestion should undergo endoscopy within 12 to 24 h to define the extent of the disease.

  3. [The technological progress in haemodialysis: potassium profiling].

    Science.gov (United States)

    Kes, Petar; Racki, Sanjin; Basić-Jukić, Nikolina; Ratković-Gusić, Iva

    2008-01-01

    Patients with the end-stage renal disease often suffer from numerous concomitant diseases. The most common are complications of the cardiovascular system. During the haemodialysis treatment, rapid changes in volume status, osmolality and electrolyte composition of the blood, cause disturbances which manifest as haemodynamic instability, hypotension and cardiac arrhythmias. Especially vulnerable are elderly patients and patients with generalized atherosclerosis, diabetes mellitus, and severe anaemia. Rapid decrease in serum potassium concentration may cause fatal arrhythmias. Contemporary dialysis machines enable slow lowering of potassium concentration during the haemodialysis session (or during the acetate-free biofiltration), what significantly decreases incidence of cardiac arrhythmias and improve cardiovascular stability.

  4. Improved Synthesis Of Potassium Beta' '-Alumina

    Science.gov (United States)

    Williams, Roger M.; Jeffries-Nakamura, Barbara; Ryan, Margaret A.; O'Connor, Dennis E.; Kisor, Adam; Underwood, Mark

    1996-01-01

    Improved formulations of precursor materials synthesize nearly-phase-pure potassium beta' '-alumina solid electrolyte (K-BASE) powder. Materials are microhomogeneous powders (or, alternatively, gels) containing K(+,) Mg(2+), and Al(3+). K-BASE powder produced used in potassium-working-fluid alkali-metal thermal-to-electric conversion (K-AMTEC), in which heat-input and heat-rejection temperatures lower than sodium-working-fluid AMTEC (Na-AMTEC). Additional potential use lies in purification of pottassium by removal of sodium and calcium.

  5. Electro-optic coefficient mapping and the design, fabrication and analysis of coplanar waveguide resonators in lithium niobate

    Science.gov (United States)

    Narayan, Raghuram

    1997-12-01

    The main topics in this dissertation are (a) Investigation of Electro-Optic (EO) coefficient variation in lithium niobate and (b) the design, fabrication and analysis of coplanar waveguide resonant electrodes for EO modulators. An optical sampling technique is used to determine the EO coefficient variations in lithium niobate processed using the titanium in-diffusion technique and the Annealed Proton Exchange (APE) technique. A spatial mapping of the EO coefficients in lithium niobate is presented. The measurements enable us to quantitatively estimate the reduction in the EO coefficient as a function of the processing conditions. The results clearly indicate that samples processed using titanium in-diffusion show no degradation of the EO coefficient. Samples processed using the APE technique display a dramatic drop in the processed region immediately after the proton exchange step. Thermal annealing is shown to restore the EO coefficient in the proton exchanged regions. But the efficacy of thermal annealing is dependent on the initial proton exchange process. Prolonged thermal annealing is effective in restoring the EO coefficients provided the initial proton exchange depth is less than 1.5/mu m. Coplanar Waveguide (CPW) is a popular planar transmission line because of its tight confinement and non-dispersive nature at high frequencies (>60 GHz). In this dissertation, several CPW resonant electrodes have been fabricated, tested and analyzed. The advantage of CPW resonant electrode structure is that there is an enhancement in the field strength by a factor proportional to /sqrt[Q], where Q is the quality factor of the resonator. The dis-advantage is that the device is narrow-band in its frequency response. The focus of this dissertation is to investigate the design and fabrication issues related to CPW resonators. The results indicate the need for better design tools to properly predict the performance of the resonator and in general CPW structures. The measurements

  6. 186 183 Potassium Bromate Content of Bread

    African Journals Online (AJOL)

    2008-12-02

    Dec 2, 2008 ... This study has shown that in spite of National Agency for Food and Drug Administration and Control. (NAFDAC) campaign for bromate-free ... agents' flavourings, yeasts, and bread improver. Yeast feed on sugar to produce .... mutagenic studies show that potassium bromate is a potential cancer initiator.

  7. METHODS OF AVAILABLE POTASSIUM ASSESSMENT IN ...

    African Journals Online (AJOL)

    AGROSEARCH UIL

    Thus, it is considered important to study methods of available K extraction for better understanding of the ... response to potassium, soil test methods should have a high correlation with crop performance. (Ekpete, 1972). Also ... The bulk samples were air-dried, ground and sieved to pass through 2 mm sieve. Sub samples of.

  8. Photoconductivity and dielectric studies of potassium pentaborate ...

    Indian Academy of Sciences (India)

    Single crystal of potassium pentaborate (KB5) has been grown by solution growth technique. FTIR and laser Raman measurements are carried out to make a qualitative analysis on KB5 crystal. Dielectric behaviour of the KB5 crystal has been studied in the microwave region using K-band microwave bench equipped with ...

  9. 186 183 Potassium Bromate Content of Bread

    African Journals Online (AJOL)

    2008-12-02

    Dec 2, 2008 ... that potassium bromate affects the nutritional quality of bread as the main vitamins available in bread are ... inhalation, abdominal pain, diarrhoea, nausea, vomiting, kidney failure, hearing loss as well as ... because a cancer warning is required on the label (Starr, 2002). The World Health. Organisation in ...

  10. Spectrophotometric Determination of Losartan Potassium in Tablets

    Directory of Open Access Journals (Sweden)

    Arianne Diane A. Aniñon

    2014-06-01

    Full Text Available In the quality control of pharmaceutical products, it is of utmost importance that validated analytical methods are used to ensure the credibility of the results generated. At the time of the study, official monographs from the United States Pharmacopeia and National Formulary (USP-NF for the quantification of Losartan potassium in tablets were unavailable, denoting the need for a validated analytical procedure for the analysis of the drug. The study adapted direct and first-derivative UV spectrophotometry methods proposed by Bonfilio and others (2010 for the assay of Losartan potassium in Losartan 50 mg. capsules, then modified and validated the said procedures for the assay of Losartan potassium in Losartan 100 mg. tablets following the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH guidelines on method validation for accuracy, precision, specificity, linearity, limit of detection, and limit of quantitation. Results demonstrated that all the performance characteristics of both methods were highly satisfactory and confirmed the possible application of the methods in routine analysis of Losartan potassium tablets.

  11. 21 CFR 582.5622 - Potassium chloride.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium chloride. 582.5622 Section 582.5622 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary...

  12. 21 CFR 582.5628 - Potassium glycerophosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium glycerophosphate. 582.5628 Section 582.5628 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or...

  13. 21 CFR 582.5634 - Potassium iodide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium iodide. 582.5634 Section 582.5634 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary...

  14. Acute Renal Failure following Accidental Potassium Bromate ...

    African Journals Online (AJOL)

    Accidental poisoning is common in children. Potassium bromate is a commonly used additive and raising agent in many edibles particularly bread, a staple food worldwide, yet its accidental poisoning has hitherto, not been documented in Nigeria. We report an unusual case of acute renal failure following accidental ...

  15. 21 CFR 172.375 - Potassium iodide.

    Science.gov (United States)

    2010-04-01

    ... added to a food as a source of the essential mineral iodine, provided the maximum intake of the food as... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium iodide. 172.375 Section 172.375 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN...

  16. Nutritional potassium requirement for laying Japanese quails

    Directory of Open Access Journals (Sweden)

    Fernando Guilherme Perazzo Costa

    2011-12-01

    Full Text Available The objective of this study was to evaluate the potassium requirement for laying Japanese quails. Two hundred and forty quails were distributed in a randomized block design, with five treatments and six replicates, with eight birds each. The treatments consisted of a basal diet deficient in potassium (K (2.50 g/kg, supplemented with potassium carbonate, to replace the inert, to reach levels of 2.50, 3.50, 4.50, 5.50 and 6.50 (g/kg of K in the diet. There was a quadratic effect of K levels on feed intake, egg production, egg mass and feed conversion per egg mass and per egg dozen, estimating the requirements of 4.26, 4.41, 4.38, 4.43 and 4.48 (g/kg of K diet, respectively. There was no significant effect on the levels of K in the diet on egg weight, albumen weight, percentage of yolk or shell and yolk color. However, yolk and shell weights reduced and the albumen percentage increased linearly with increasing levels of K in the diet. Despite the reduction of shell weight, the increased levels of K did not influence the specific gravity and shell thickness. The use of 4.41 g/kg of potassium is recommended in the diet for laying Japanese quails.

  17. Acute Renal Failure following Accidental Potassium

    African Journals Online (AJOL)

    . Summary. Okeniyi JAO, Aladekomo TA, Oyelami 0A. Acute Renal Failure following Accidental. Potassium ... Serum Electrvgyte and Urea lef in the Patient '. ' D91 4 Dry 7 D49! ... determination of bromate residues with accuracy in a variety of ...

  18. Effect of potassium on micromorphological and chemical ...

    African Journals Online (AJOL)

    An experiment was conducted at National Agricultural Research Centre (NARC), Islamabad, Pakistan to study the effect of potassium on yield and internal leaf tissues composition of cotton varieties, CIM-443, CIM-109 and CIM-446. Nitrogen (N) and phosphorus (P) were applied at 150 mg N/kg soil and 75 mg P 2O5/kg soil ...

  19. Catalytic decomposition of potassium monopersulfate: the kinetics

    OpenAIRE

    Borralho, Maria Teresa; Gimeno, Olga; RIVAS, Javier; Carbajo, Maria

    2009-01-01

    Potassium monopersulfate has been decomposed in aqueous solution in the presence of Co(II). The process has been simulated by means of a mechanism based on elementary reactions. Rate constants have been taken from literature reports or, alternatively, assimilated to analogous reactions occurring in Fenton´s chemistry. Several operating conditions have been successfully applied.

  20. Qualitative Carbohydrate Analysis using Alkaline Potassium ...

    Indian Academy of Sciences (India)

    IAS Admin

    Carbohydrates form a distinct class of organic compounds often identified by their characteristic behaviour towards a host of reagents [1–4]. Based on a kinetic study on the oxidation of carbohydrates with alkaline potassium ferricyanide [5], we had reported, in the April 2007 issue of Resonance, an unambiguous.

  1. Selective Monohydrocyanation of Diimine using Potassium ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 128; Issue 12. Selective Monohydrocyanation of Diimine using Potassium Hexacyanoferrate(II)-Benzoyl Chloride Reagent System as a Cyanide Source. ZHENG LI FEI WEN JINGYA YANG. Regular Article Volume 128 Issue 12 December 2016 pp 1849-1853 ...

  2. Effect of potassium on micromorphological and chemical ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-08-04

    Aug 4, 2009 ... observed in plant leaves grown without potassium application while in leaves supplied with K their ... available level of its cations in soil and fixation capacity of soil. ... two-third of the total K uptake occurs during a 6-week ...

  3. Relationship Between Extractable Potassium And Phosphorus ...

    African Journals Online (AJOL)

    The effect of laboratory soil sample preparation on level of extractable Potassium (K) and Phosphorus (P) was studied on various soil types collected at Magoebaskloof pine farm (MPF), Tshiombho irrigation scheme (TIS), Dal water farm (DWF) and Syferkuil experimental farm (SEF). Twenty soil samples were collected at ...

  4. Effect Of Virkon Disinfectant Brand Of Potassium ...

    African Journals Online (AJOL)

    In the Nigerian market are many brands of disinfectants with varying efficacy against bacteria, fungi and viruses. Recently Virkon brand of potassium monoperoxysulphate (Antec, UK) was introduced. The Kelsey -Sykes test was carried out to determine the efficacy of Virkon against standard bacterial strains and ...

  5. Integrated source of tunable nonmaximally mode-entangled photons in a domain-engineered lithium niobate waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Ming, Yang; Wu, Zi-jian; Xu, Fei, E-mail: feixu@nju.edu.cn; Lu, Yan-qing, E-mail: yqlu@nju.edu.cn [National Laboratory of Solid State Microstructures and College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093 (China); Cui, Guo-xin [National Laboratory of Solid State Microstructures and College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093 (China); Key Laboratory of Nanodevices and Nanoapplications, Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, Suzhou 215000 (China); Tan, Ai-hong [Laboratory for Quantum Information, China Jiliang University, Hangzhou 310018 (China)

    2014-04-28

    The nonmaximally entangled state is a special kind of entangled state, which has important applications in quantum information processing. It has been generated in quantum circuits based on bulk optical elements. However, corresponding schemes in integrated quantum circuits have been rarely considered. In this Letter, we propose an effective solution for this problem. An electro-optically tunable nonmaximally mode-entangled photon state is generated in an on-chip domain-engineered lithium niobate (LN) waveguide. Spontaneous parametric down-conversion and electro-optic interaction are effectively combined through suitable domain design to transform the entangled state into our desired formation. Moreover, this is a flexible approach to entanglement architectures. Other kinds of reconfigurable entanglements are also achievable through this method. LN provides a very promising platform for future quantum circuit integration.

  6. Site-selective measurement of relaxation properties at 980 nm in Er^{3+}-doped congruent and stoichiometric lithium niobate crystals

    Science.gov (United States)

    Mandula, Gabor; Kis, Zsolt; Kovacs, Laszlo; Szaller, Zsuzsanna; Krampf, Andreas

    2016-04-01

    A pump-probe-type saturation spectroscopic experiment has been performed at 980 nm to measure the homogeneous linewidth of the ^4I_{11/2}-^4I_{15/2} transition and the lifetime of the ^4I_{11/2} state of erbium embedded into lithium niobate single crystals. There are several non-equivalent Er^{3+}_{Li^+}-V_{Li^+} sites with differently oriented defect structure for charge compensation. These non-equivalent centers differ in their transition energies. Hence, our measurements have been done at two nearby frequencies, addressing groups of erbium ions located at non-equivalent sites. The results are compared with lifetime calculations and measurements found in the literature and with the predictions of our simple model calculation.

  7. Triple-wavelength Nd-laser system by cascaded electro-optic periodically poled lithium niobate Bragg modulator.

    Science.gov (United States)

    Lin, Shou-Tai; Hsieh, Chuan-Sheng

    2012-12-31

    This study presents a diode-pumped cw triple-wavelength Nd:GdVO₄ laser system using an electro-optic periodically poled lithium niobate (PPLN) Bragg modulator. The PPLN consists of two cascaded sections, 20.3 μm and 25.7 μm, functioning as loss modulators for 1063 and 1342 nm at the same Bragg incident angle. When switching the dc voltages on PPLN and applying 25 W pump power, the output wavelength can be selected among 912, 1063, and 1342 nm with output power of 2, 5, and 1.4 W, respectively. The device is capable of triple-wavelength generation simultaneous when applied voltages are 180 (Λ = 20.3 μm) and -50 V (Λ = 25.7 μm) at a 25 W pump power. Gain competition induced power instability was also observed.

  8. Random-field Potts model for the polar domains of lead magnesium niobate and lead scandium tantalate

    Energy Technology Data Exchange (ETDEWEB)

    Qian, H.; Bursill, L.A

    1997-06-01

    A random filed Potts model is used to establish the spatial relationship between the nanoscale distribution of charges chemical defects and nanoscale polar domains for the perovskite-based relaxor materials lead magnesium niobate (PMN) and lead scandium tantalate (PST). The random fields are not set stochastically but are determined initially by the distribution of B-site cations (Mg, Nb) or (Sc, Ta) generated by Monte Carlo NNNI-model simulations for the chemical defects. An appropriate random field Potts model is derived and algorithms developed for a 2D lattice. It is shown that the local fields are strongly correlated with the chemical domain walls and that polar domains as a function of decreasing temperature is simulated for the two cases of PMN and PST. The dynamics of the polar clusters is also discussed. 33 refs., 9 figs.

  9. Dual-channel cathodic electrochemiluminescence of luminol induced by injection of hot electrons on a niobate semiconductor modified electrode.

    Science.gov (United States)

    Xu, Huifeng; Ye, Hongzhi; Zhu, Xi; Liang, Shijing; Guo, Longhua; Lin, Zhenyu; Liu, Xianxiang; Chen, Guonan

    2013-01-07

    In this paper, a new niobate semiconductor photocatalyst Sr(0.4)H(1.2)Nb(2)O(6)·H(2)O (HSN) nanoparticle was applied to investigate the cathodic electrochemiluminescent (ECL) behavior of luminol for the first time. The results presented here demonstrated that there were two ECL peaks of luminol at the cathodic potential attributed to immobilization of HSN on the electrode surface. It is implied that HSN can be electrically excited and injected electrons into aqueous electrolytes from this electrode under a quite low potential that only excites luminol. A mechanism for this luminol-ECL system on HSN/GCE has been proposed. Additionally, this HSN/GCE has lots of advantages, such as high stability, good anti-interference ability, simple instrumentation, rapid procedure and ultrasensitive ECL response. It is envisioned that this HSN/GCE has further applications in biosensors.

  10. Frequency conversion between UV and telecom wavelengths in a lithium niobate waveguide for quantum communication with Yb+ trapped ions

    CERN Document Server

    Kasture, Sachin; Haylock, Ben; Boes, Andreas; Mitchell, Arnan; Streed, Erik W; Lobino, Mirko

    2016-01-01

    We study and demonstrate the frequency conversion of UV radiation, resonant with 369.5 nm transition in Yb+ ions to the C-band wavelength 1580.3 nm and vice-versa using a reverse proton-exchanged waveguide in periodically poled lithium niobate. Our integrated device can interface trapped Yb+ ions with telecom infrastructure for the realization of an Yb+ based quantum repeater protocol and to efficiently distribute entanglement over long distances. We analyse the single photon frequency conversion efficiency from the 369.525 nm to the telecom wavelength and its dependence on pump power, device length and temperature. The single-photon noise generated by spontaneous Raman scattering of the pump is also measured. From this analysis we estimate a single photon conversion efficiency of 9% is achievable with our technology with almost complete suppression of the Raman noise.

  11. Enhanced Cherenkov phase matching terahertz wave generation via a magnesium oxide doped lithium niobate ridged waveguide crystal

    Science.gov (United States)

    Takeya, K.; Minami, T.; Okano, H.; Tripathi, S. R.; Kawase, K.

    2017-01-01

    When combined with a nonlinear waveguide crystal, Cherenkov phase matching allows for highly effective generation of high power and broadband terahertz (THz) waves. Using a ridged Lithium Niobate (LiNbO3) waveguide coupled with a specially designed silicon lens, we successfully generated THz waves with intensity of approximately three orders of magnitude stronger than those from conventional photoconductive antenna. The broadband spectrum was from 0.1 THz to 7 THz with a maximum dynamic range of 80 dB. The temporal shape of time domain pulse is a regular single cycle which could be used for high depth resolution time of flight tomography. The generated THz wave can also be easily monitored by compact room-temperature THz camera, enabling us to determine the spatial characteristics of the THz propagation.

  12. Enhanced Cherenkov phase matching terahertz wave generation via a magnesium oxide doped lithium niobate ridged waveguide crystal

    Directory of Open Access Journals (Sweden)

    K. Takeya

    2017-01-01

    Full Text Available When combined with a nonlinear waveguide crystal, Cherenkov phase matching allows for highly effective generation of high power and broadband terahertz (THz waves. Using a ridged Lithium Niobate (LiNbO3 waveguide coupled with a specially designed silicon lens, we successfully generated THz waves with intensity of approximately three orders of magnitude stronger than those from conventional photoconductive antenna. The broadband spectrum was from 0.1 THz to 7 THz with a maximum dynamic range of 80 dB. The temporal shape of time domain pulse is a regular single cycle which could be used for high depth resolution time of flight tomography. The generated THz wave can also be easily monitored by compact room-temperature THz camera, enabling us to determine the spatial characteristics of the THz propagation.

  13. Fabrication of polarization-independent waveguides deeply buried in lithium niobate crystal using aberration-corrected femtosecond laser direct writing

    Science.gov (United States)

    Wang, Peng; Qi, Jia; Liu, Zhengming; Liao, Yang; Chu, Wei; Cheng, Ya

    2017-01-01

    Writing optical waveguides with femtosecond laser pulses provides the capability of forming three-dimensional photonic circuits for manipulating light fields in both linear and nonlinear manners. To fully explore this potential, large depths of the buried waveguides in transparent substrates are often desirable to facilitate achieving vertical integration of waveguides in a multi-layer configuration, which, however, is hampered by rapidly degraded axial resolution caused by optical aberration. Here, we show that with the correction of the spherical aberration, polarization-independent waveguides can be inscribed in a nonlinear optical crystal lithium niobate (LN) at depths up to 1400 μm, which is more than one order of magnitude deeper than the waveguides written with aberration uncorrected femtosecond laser pulses. Our technique is beneficial for applications ranging from miniaturized nonlinear light sources to quantum information processing.

  14. Absorption behavior in graphene-based one-dimensional photonic crystals containing a x-cut lithium niobate layer

    Science.gov (United States)

    Rashidi, Arezou; Namdar, Abdolrahman; Abdi-Ghaleh, Reza

    2017-05-01

    This paper theoretically shows that nearly perfect absorption can be achieved by adjusting the period numbers of the two graphene based photonic crystals surrounding a lithium niobate (LiNbO3) layer. Since LiNbO3 is an electro-optical (EO) material with voltage dependent refractive index and high EO coefficient, peak wavelength tunability of absorption has been revealed. Our investigations show that the relation between the peak wavelength and applied external voltage is linear, so that the peak wavelength moves toward shorter wavelengths by increasing the applied external voltage. Moreover, it is possible to achieve multi-peak by varying the thickness of LiNbO3 defect layer. Finally, we discuss the possibility of control of the absorption via controllable parameter (chemical potential) of the graphene. The results indicate that for a given structure, i.e, definite period numbers surrounding the LNO layer, the enhanced absorption can be achieved, by adjusting the chemical potential.

  15. Imaging the ultrafast Kerr effect, free carrier generation, relaxation and ablation dynamics of Lithium Niobate irradiated with femtosecond laser pulses

    Science.gov (United States)

    Garcia-Lechuga, Mario; Siegel, Jan; Hernandez-Rueda, Javier; Solis, Javier

    2014-09-01

    The interaction of high-power single 130 femtosecond (fs) laser pulses with the surface of Lithium Niobate is experimentally investigated in this work. The use of fs-resolution time-resolved microscopy allows us to separately observe the instantaneous optical Kerr effect induced by the pulse and the generation of a free electron plasma. The maximum electron density is reached 550 fs after the peak of the Kerr effect, confirming the presence of a delayed carrier generation mechanism. We have also observed the appearance of transient Newton rings during the ablation process, related to optical interference of the probe beam reflected at the front and back surface of the ablating layer. Finally, we have analyzed the dynamics of the photorefractive effect on a much longer time scale by measuring the evolution of the transmittance of the irradiated area for different fluences below the ablation threshold.

  16. Lithium niobate Q-switch to prevent pre-lasing of high gain lasers operating over a wide temperature range

    Science.gov (United States)

    Jundt, Dieter H.; MacKay, Peter E.

    2015-02-01

    Because of its ease of growth and large electro-optic effect, lithium niobate is the preferred choice for Q-switching mobile lasers. Temperature-induced pyro-electric charges however may lead to premature lasing. We manufactured and characterized temperature-stable LN Q-switch. A thermo-chemical anneal was performed creating a conductive material layer 0.5mm thick with increased conductivity. While this increases optical insertion loss by a few percent, this is tolerable in high gain lasers. We present details of treatment, the surface charge creation and dissipation mechanism and the setup used to assess the cold-performance used to demonstrate improved charge dissipation when compared to untreated crystals.

  17. Determinants of renal potassium excretion in critically ill patients : The role of insulin therapy

    NARCIS (Netherlands)

    Hoekstra, Miriam; Yeh, Lu; Oude Lansink, Annemieke; Vogelzang, Mathijs; Stegeman, Coen A.; Rodgers, Michael G. G.; van der Horst, Iwan C. C.; Wietasch, Gotz; Zijlstra, Felix; Nijsten, Maarten W. N.

    Objectives: Insulin administration lowers plasma potassium concentration by augmenting intracellular uptake of potassium. The effect of insulin administration on renal potassium excretion is unclear. Some studies suggest that insulin has an antikaliuretic effect although plasma potassium levels were

  18. 21 CFR 582.1129 - Aluminum potassium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aluminum potassium sulfate. 582.1129 Section 582.1129 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1129 Aluminum potassium sulfate. (a) Product. Aluminum potassium sulfate. (b) Conditions of...

  19. 21 CFR 182.1129 - Aluminum potassium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aluminum potassium sulfate. 182.1129 Section 182.1129 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1129 Aluminum potassium sulfate. (a) Product. Aluminum potassium sulfate. (b...

  20. 21 CFR 184.1077 - Potassium acid tartrate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium acid tartrate. 184.1077 Section 184.1077... Listing of Specific Substances Affirmed as GRAS § 184.1077 Potassium acid tartrate. (a) Potassium acid... accordance with § 184.1(b)(1), the ingredient is used in food with no limitation other than current good...

  1. 40 CFR 721.10031 - Lithium potassium titanium oxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Lithium potassium titanium oxide. 721... Substances § 721.10031 Lithium potassium titanium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lithium potassium titanium oxide (PMN P-02...

  2. 21 CFR 181.33 - Sodium nitrate and potassium nitrate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrate and potassium nitrate. 181.33...-Sanctioned Food Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and potassium nitrate are subject to prior sanctions issued by the U.S. Department of Agriculture for use as sources of...

  3. Sodium-lithium niobate piezoceramics prepared by mechanochemical activation assisted methods

    Directory of Open Access Journals (Sweden)

    Pardo, L.

    2004-02-01

    Full Text Available The environmental protection issues are driving forces nowadays in the scientific research on materials. From this point of view, it is a need to find alternatives to the present commercial piezoceramics, based on lead titanates-zirconates. The production of these materials requires handling of big amounts of lead oxide, which is highly toxic. Alkaline niobate piezoceramics are considered a good alternative for the future substitution of commercial piezoceramics by lead-free materials. However, the processing of these ceramics is difficult by conventional ceramic routes. There is a need to search for new routes of processing. The mechanochemical activation was used in this work for the first time to get Na1-xLixNbO3 ceramics in the Na rich region. Stoichiometric mixtures of Na2CO3 or Na2O, Li2CO3 and Nb2O5 were activated in a vibrating mill. A progressive broadening of the X-ray diffraction peaks of the mixtures was observed as the milling time increased. Nevertheless, the precursors did not became fully amorphous. The thermal evolution of the activated precursors was also tested. Ceramics were obtained by sintering or hot pressing and their piezoelectric properties were studied.

    La protección medioambiental es uno de los factores que impulsan diversas áreas de la investigación en materiales. Existe la necesidad de la búsqueda de alternativas a las cerámicas ferro-piezoeléctricas comerciales basadas en los titanatos-circonatos de plomo, que requieren el manejo de grandes cantidades de óxido de plomo, muy tóxico, en su procesado. Los niobatos alcalinos se consideran buenos candidatos para esta sustitución. Sin embargo, es difícil conseguir cerámicas con altas densificaciones. De aquí la necesidad de investigar nuevas rutas de procesado. La activación mecanoquímica se ha utilizado por primera vez en este trabajo para obtener cerámicas de Na1-xLixNbO3, en la región rica en Na. Se han activado mecanoquímicamente mezclas

  4. PHOSPHORUS-POTASSIUM AND NITROGEN-PHOSPHORUS-POTASSIUM FERTILIZER BASED ON WASHED AND DRIED CONCENTRATE FROM CENTRAL KYZYLKUM PHOSPHORITE

    OpenAIRE

    NAZIROVA RAXNAMO MUXTAROVNA; TADJIEV SAYFUDDIN MUKHTAROVICH; TUKHTAYEV SAYDIAXRAL

    2016-01-01

    In this article the findings on the production of complex phosphorus-potassium and nitrogen-phosphorus-potassium fertilizer by decomposition of washed and dried phosphoconcentrate from Central Kyzylkum phosphorite with incomplete norms of sulfuric acid with the addition of potassium chloride, sulfate, ammonium nitrate and urea have been given. It has been revealed that the addition of potassium chloride and ammonium salts significantly affect on expansion coefficient and NP and NPK fertilizer...

  5. Physicochemical action of potassium-magnesium citrate in nephrolithiasis

    Science.gov (United States)

    Pak, C. Y.; Koenig, K.; Khan, R.; Haynes, S.; Padalino, P.

    1992-01-01

    Effect of potassium-magnesium citrate on urinary biochemistry and crystallization of stone-forming salts was compared with that of potassium citrate at same dose of potassium in five normal subjects and five patients with calcium nephrolithiasis. Compared to the placebo phase, urinary pH rose significantly from 6.06 +/- 0.27 to 6.48 +/- 0.36 (mean +/- SD, p less than 0.0167) during treatment with potassium citrate (50 mEq/day for 7 days) and to 6.68 +/- 0.31 during therapy with potassium-magnesium citrate (containing 49 mEq K, 24.5 mEq Mg, and 73.5 mEq citrate per day). Urinary pH was significantly higher during potassium-magnesium citrate than during potassium citrate therapy. Thus, the amount of undissociated uric acid declined from 118 +/- 61 mg/day during the placebo phase to 68 +/- 54 mg/day during potassium citrate treatment and, more prominently, to 41 +/- 46 mg/day during potassium-magnesium citrate therapy. Urinary magnesium rose significantly from 102 +/- 25 to 146 +/- 37 mg/day during potassium-magnesium citrate therapy but not during potassium citrate therapy. Urinary citrate rose more prominently during potassium-magnesium citrate therapy (to 1027 +/- 478 mg/day from 638 +/- 252 mg/day) than during potassium citrate treatment (to 932 +/- 297 mg/day). Consequently, urinary saturation (activity product) of calcium oxalate declined significantly (from 1.49 x 10(-8) to 1.03 x 10(-8) M2) during potassium-magnesium citrate therapy and marginally (to 1.14 x 10(-8) M2) during potassium citrate therapy.(ABSTRACT TRUNCATED AT 250 WORDS).

  6. Effects of cisplatin on potassium currents in CT26 cells

    Directory of Open Access Journals (Sweden)

    Naveen Sharma

    2016-01-01

    Conclusion: Potassium currents were detected in CT26 cells and the currents were reduced by the application of tetraethylammonium (TEA chloride, iberiotoxin, a big conductance calcium-activated potassium channel blocker and barium. The potassium currents were enhanced to 192< by the application of cisplatin (0.5 mM. Moreover, the increase of potassium currents by cisplatin was further inhibited by the application of TEA confirming the action of cisplatin on potassium channels. In addition, relative current induced by cisplatin in CT26 cells was bit larger than in normal IEC-6 cells.

  7. High-performance and linear thin-film lithium niobate Mach-Zehnder modulators on silicon up to 50  GHz.

    Science.gov (United States)

    Rao, Ashutosh; Patil, Aniket; Rabiei, Payam; Honardoost, Amirmahdi; DeSalvo, Richard; Paolella, Arthur; Fathpour, Sasan

    2016-12-15

    Compact electro-optical modulators are demonstrated on thin films of lithium niobate on silicon operating up to 50 GHz. The half-wave voltage length product of the high-performance devices is 3.1 V.cm at DC and less than 6.5 V.cm up to 50 GHz. The 3 dB electrical bandwidth is 33 GHz, with an 18 dB extinction ratio. The third-order intermodulation distortion spurious free dynamic range is 97.3  dBHz2/3 at 1 GHz and 92.6  dBHz2/3 at 10 GHz. The performance demonstrated by the thin-film modulators is on par with conventional lithium niobate modulators but with lower drive voltages, smaller device footprints, and potential compatibility for integration with large-scale silicon photonics.

  8. Adaptation of Bacillus subtilis to Life at Extreme Potassium Limitation

    Directory of Open Access Journals (Sweden)

    Jan Gundlach

    2017-07-01

    Full Text Available Potassium is the most abundant metal ion in every living cell. This ion is essential due to its requirement for the activity of the ribosome and many enzymes but also because of its role in buffering the negative charge of nucleic acids. As the external concentrations of potassium are usually low, efficient uptake and intracellular enrichment of the ion is necessary. The Gram-positive bacterium Bacillus subtilis possesses three transporters for potassium, KtrAB, KtrCD, and the recently discovered KimA. In the absence of the high-affinity transporters KtrAB and KimA, the bacteria were unable to grow at low potassium concentrations. However, we observed the appearance of suppressor mutants that were able to overcome the potassium limitation. All these suppressor mutations affected amino acid metabolism, particularly arginine biosynthesis. In the mutants, the intracellular levels of ornithine, citrulline, and arginine were strongly increased, suggesting that these amino acids can partially substitute for potassium. This was confirmed by the observation that the supplementation with positively charged amino acids allows growth of B. subtilis even at the extreme potassium limitation that the bacteria experience if no potassium is added to the medium. In addition, a second class of suppressor mutations allowed growth at extreme potassium limitation. These mutations result in increased expression of KtrAB, the potassium transporter with the highest affinity and therefore allow the acquisition and accumulation of the smallest amounts of potassium ions from the environment.

  9. Potassium tetracyanidoaurate(III monohydrate: a redetermination

    Directory of Open Access Journals (Sweden)

    Nobuyuki Matsushita

    2017-03-01

    Full Text Available The structure of the title metal complex salt, K[Au(CN4]·H2O, has been redetermined using X-ray diffraction data at 173 K in order to improve the precision. The previous determination was based on neutron diffraction data [Bertinotti & Bertinotti (1970. Acta Cryst. B26, 422–428]. The title compound crystallizes in the space group P212121 with one potassium cation, one [Au(CN4]− anion and one water molecule in the asymmetric unit. The AuIII atom lies on a general position and has an almost square-planar coordination sphere defined by four cyanide ligands. Interactions between the potassium cation and N atoms of the complex anion, as well as O—H...N hydrogen bonds, lead to the formation of a three-dimensional framework structure.

  10. Single-mode visible and mid-infrared periodically poled lithium niobate optical parametric oscillator amplified in perylene red doped poly(methyl methacrylate)

    Science.gov (United States)

    Schlup, Philip; W. Baxter, Glenn; McKinnie, Iain T.

    2000-10-01

    We have demonstrated a simple grazing-incidence optical parametric oscillator (OPO) based on periodically poled lithium niobate (PPLN) capable of generating single-mode visible (619-640 nm) and infrared (3.16-3.77 μm) radiation. The single-mode (poly(methyl methacrylate) disc was used to amplify the signal wavelength up to 114 μJ in a single pass without broadening the optical bandwidth.

  11. A novel potassium channel in photosynthetic cyanobacteria.

    Directory of Open Access Journals (Sweden)

    Manuela Zanetti

    Full Text Available Elucidation of the structure-function relationship of a small number of prokaryotic ion channels characterized so far greatly contributed to our knowledge on basic mechanisms of ion conduction. We identified a new potassium channel (SynK in the genome of the cyanobacterium Synechocystis sp. PCC6803, a photosynthetic model organism. SynK, when expressed in a K(+-uptake-system deficient E. coli strain, was able to recover growth of these organisms. The protein functions as a potassium selective ion channel when expressed in Chinese hamster ovary cells. The location of SynK in cyanobacteria in both thylakoid and plasmamembranes was revealed by immunogold electron microscopy and Western blotting of isolated membrane fractions. SynK seems to be conserved during evolution, giving rise to a TPK (two-pore K(+ channel family member which is shown here to be located in the thylakoid membrane of Arabidopsis. Our work characterizes a novel cyanobacterial potassium channel and indicates the molecular nature of the first higher plant thylakoid cation channel, opening the way to functional studies.

  12. Potassium Permanganate Poisoning: A Nonfatal Outcome

    Directory of Open Access Journals (Sweden)

    Suzan M. Eteiwi

    2015-07-01

    Full Text Available Acute poisoning by potassium permanganate is a rare condition with high morbidity and mortality. Diagnosis of the condition relies on a history of exposure or ingestion and a high degree of clinical suspicion. Oxygen desaturation and the presence of methemoglobin are also helpful indicators. Since no specific antidote is available, treatment is mainly supportive. Few cases have been reported in the literature following potassium permanganate ingestion, whether intentional or accidental, and most of the patients in these cases had unfavorable outcomes, which was not the case in our patient. Our patient, a 73-year-old male, purchased potassium permanganate over the counter mistaking it for magnesium salt, which he frequently used as a laxative. Several hours after he ingested it, he was admitted to the endocrine department at King Hussein Medical Center, Jordan, with acute rapidly evolving shortness of breath. During hospitalization, his liver function tests deteriorated. Since he was diagnosed early and managed promptly he had a favorable outcome.

  13. Spectral evolution of Eu{sup 3+} doped Y{sub 3}NbO{sub 7} niobate induced by temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K-Y.; Durand, A. [CNRS, ICMCB, UPR 9048, F-33600 Pessac (France); Univ. Bordeaux, ICMCB, UPR 9048, F-33600 Pessac (France); Heintz, J-M.; Veillere, A. [CNRS, ICMCB, UPR 9048, F-33600 Pessac (France); Univ. Bordeaux, ICMCB, UPR 9048, F-33600 Pessac (France); Bordeaux INP, ICMCB, UPR 9048, F-33600 Pessac (France); Jubera, V., E-mail: veronique.jubera@u-bordeaux.fr [CNRS, ICMCB, UPR 9048, F-33600 Pessac (France); Univ. Bordeaux, ICMCB, UPR 9048, F-33600 Pessac (France)

    2016-03-15

    A Eu{sup 3+} doped Y{sub 3}NbO{sub 7} niobate powder was synthetized using a polymerizable complex route. It gave rise to nanometric particles that crystallized in the fluorine structure, corresponding to the Y{sub 3}NbO{sub 7} phase. The thermal evolution of this powder was followed up to 1600 °C, using X-ray diffraction and optical characterizations. The fluorine structure was maintained in the whole temperature range. However, spectral evolution of the samples calcined above 900 °C showed a more complex situation. Emission spectra of powders heat treated at different temperatures showed an evolution of the emission lines that can be attributed first to a better crystallization of the niobate phase and second to its partial decomposition in favor of the formation of YNbO{sub 4} and Y{sub 2}O{sub 3}. Although the Y{sub 3}NbO{sub 7} phase appeared stable up to 1650 °C, from X-ray diffraction analysis, spectral analysis showed that the local environment of the doping element is modified from 1100 °C. - Graphical abstract: Spectral evolution of Eu{sup 3+} doped Y{sub 3}NbO{sub 7} niobate induced by temperature.

  14. Race, Serum Potassium, and Associations With ESRD and Mortality.

    Science.gov (United States)

    Chen, Yan; Sang, Yingying; Ballew, Shoshana H; Tin, Adrienne; Chang, Alex R; Matsushita, Kunihiro; Coresh, Josef; Kalantar-Zadeh, Kamyar; Molnar, Miklos Z; Grams, Morgan E

    2017-08-01

    Recent studies suggest that potassium levels may differ by race. The basis for these differences and whether associations between potassium levels and adverse outcomes differ by race are unknown. Observational study. Associations between race and potassium level and the interaction of race and potassium level with outcomes were investigated in the Racial and Cardiovascular Risk Anomalies in Chronic Kidney Disease (RCAV) Study, a cohort of US veterans (N=2,662,462). Associations between African ancestry and potassium level were investigated in African Americans in the Atherosclerosis Risk in Communities (ARIC) Study (N=3,450). Race (African American vs non-African American and percent African ancestry) for cross-sectional analysis; serum potassium level for longitudinal analysis. Potassium level for cross-sectional analysis; mortality and end-stage renal disease for longitudinal analysis. The RCAV cohort was 18% African American (N=470,985). Potassium levels on average were 0.162mmol/L lower in African Americans compared with non-African Americans, with differences persisting after adjustment for demographics, comorbid conditions, and potassium-altering medication use. In the ARIC Study, higher African ancestry was related to lower potassium levels (-0.027mmol/L per each 10% African ancestry). In both race groups, higher and lower potassium levels were associated with mortality. Compared to potassium level of 4.2mmol/L, mortality risk associated with lower potassium levels was lower in African Americans versus non-African Americans, whereas mortality risk associated with higher levels was slightly greater. Risk relationships between potassium and end-stage renal disease were weaker, with no difference by race. No data for potassium intake. African Americans had slightly lower serum potassium levels than non-African Americans. Consistent associations between potassium levels and percent African ancestry may suggest a genetic component to these differences. Higher and

  15. Isohydric regulation of plasma potassium by bicarbonate in the rat.

    Science.gov (United States)

    Fraley, D S; Adler, S

    1976-04-01

    pH and bicarbonate affect many metabolic reactions but each may change independently. To study bicarbonate's effect onplasma potassium, blood bicarbonate in normal, hypokalemic or hyperkalemic rats was either maintained constant, lowered by hydrochloric acid or raised by sodium bicarbonate administraion. Blood pH was maintained constant by changing PCO2. In normokalemia lowering bicarbonate increased plasma potassium 2.0mEq above values obtained in the other groups. To eliminate urinary potassium losses, experiments were also performed in rats with bilateral ureteral ligation. Again, plasma potassium concentration rose significantly more in the lowered bicarbonate group. Similarly, in hypokalemia, plasma potassium rose 1.2 and 0.4mEq in the lowered and unchanged groups, but fell 0.2mEq/liter in the elevated group. Differences could not be ascribed to renal potassium losses as potassium excretion was essentially zero in each group. In hyperkalemia, plasma potassium concentration remained elevated for 150 min in the lowered bicarbonate group but fell 1.3 and 2.0mEq in the unchanged and elevated groups, respectively. Urinary potassium losses in the three groups were statistically identical. In all experiments blood pH was maintained unchanged during the experiment. The data show that bicarbonate, independent of blood pH, alters transcellular potassium distribution suggesting the usefulness of bicarbonate therapy in hyperkalemia even at a compensated blood pH.

  16. Proapoptotic Role of Potassium Ions in Liver Cells

    Directory of Open Access Journals (Sweden)

    Zhenglin Xia

    2016-01-01

    Full Text Available Potassium channels are transmembrane proteins that selectively promote the infiltration of potassium ions. The significance of these channels for tumor biology has become obvious. However, the effects of potassium ions on the tumor or normal cells have seldom been studied. To address this problem, we studied the biological effects of L02 and HepG2 cells with ectogenous potassium ions. Cell proliferation, cell cycle, and apoptosis rate were analyzed. Our results indicated that potassium ions inhibited proliferation of L02 and HepG2 cells and promoted their apoptosis. Potassium ions induced apoptosis through regulating Bcl-2 family members and depolarized the mitochondrial membrane, especially for HepG2 cell. These biological effects were associated with channel protein HERG. By facilitating expression of channel protein HERG, potassium ions may prevent it from being shunted to procancerous pathways by inducing apoptosis. These results demonstrated that potassium ions may be a key regulator of liver cell function. Thus, our findings suggest that potassium ions could inhibit tumorigenesis through inducing apoptosis of hepatoma cells by upregulating potassium ions transport channel proteins HERG and VDAC1.

  17. Adaptation of Bacillus subtilis to Life at Extreme Potassium Limitation.

    Science.gov (United States)

    Gundlach, Jan; Herzberg, Christina; Hertel, Dietrich; Thürmer, Andrea; Daniel, Rolf; Link, Hannes; Stülke, Jörg

    2017-07-05

    Potassium is the most abundant metal ion in every living cell. This ion is essential due to its requirement for the activity of the ribosome and many enzymes but also because of its role in buffering the negative charge of nucleic acids. As the external concentrations of potassium are usually low, efficient uptake and intracellular enrichment of the ion is necessary. The Gram-positive bacterium Bacillus subtilis possesses three transporters for potassium, KtrAB, KtrCD, and the recently discovered KimA. In the absence of the high-affinity transporters KtrAB and KimA, the bacteria were unable to grow at low potassium concentrations. However, we observed the appearance of suppressor mutants that were able to overcome the potassium limitation. All these suppressor mutations affected amino acid metabolism, particularly arginine biosynthesis. In the mutants, the intracellular levels of ornithine, citrulline, and arginine were strongly increased, suggesting that these amino acids can partially substitute for potassium. This was confirmed by the observation that the supplementation with positively charged amino acids allows growth of B. subtilis even at the extreme potassium limitation that the bacteria experience if no potassium is added to the medium. In addition, a second class of suppressor mutations allowed growth at extreme potassium limitation. These mutations result in increased expression of KtrAB, the potassium transporter with the highest affinity and therefore allow the acquisition and accumulation of the smallest amounts of potassium ions from the environment.IMPORTANCE Potassium is essential for every living cell as it is required for the activity for many enzymes and for maintaining the intracellular pH by buffering the negative charge of the nucleic acids. We have studied the adaptation of the soil bacterium Bacillus subtilis to life at low potassium concentrations. If the major high-affinity transporters are missing, the bacteria are unable to grow unless

  18. Cefadroxil iodometric determination by potassium hydrogenperoxomonosulfate reaction

    Directory of Open Access Journals (Sweden)

    Юлія Юріївна Сердюкова

    2015-10-01

    Full Text Available Aim. Simple methods of oxidimetric determination of β-lactam antibiotic cefadroxil in pure powder and in capsules, that are based on S-oxidation reactions by potassium hydrogenperoxomonosulphate acid in weak acid medium to S- oxide with following iodometric quantitative determination of the oxydator reagent excess were developed.Materials and methods. A triple potassium salt of caroate acid, 2KHSO5•KHSO4•K2SO4 (commercial «Oxone®» DuPont, production was used as oxidizing agent.Results. By the results of reaction kinetics using iodometric titration it was determined that redox reaction between cefadroxil and potassium hydrogenperoxomonosulfate is quantified and a stoichiometric: 1 mol of cefadroxil is per 1 mol of potassium hydrogen. Quantitative oxidation of Sulfur atom was finished in the time that is less than 1 min. The mean recovery of the main substance in the cefadroxil pure substance was 97.76%, RSD=1.33 % (δ=1.31 %, 1 mL of the standard 0.0200 mol L-1 sodium tiosulphate solution corresponds to 0.003634 g of sodium cefadroxil (C16H17N3O5S which should be 95–102 % in the pure anhydrous substance. The mean recovery of medical preparation “Cefadroxil”, 500 mg is 100.06 %, RSD=0.96 % (δ=1.01 %, which should be 92.5–107.5 %, in anhydrous preparation. The limit detection is С=0.05 mg mL-1. The advantages of the proposed procedure are the ability to assay cefadroxil by the biologically active part of the molecule (alicyclic and tiomethyl sulfur, good recovery and the accuracy of results.Conclusions. The obtained validation data meet the requirements of the State Pharmacopoeia of Ukraine, which indicates the possibility of its introduction in the practice of analytical laboratories analysis, or application during the stepwise control process or manufacturing of drugs quality control during equipment washing

  19. Magnetoelectric coupling of multiferroic chromium doped barium titanate thin film probed by magneto-impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Jyoti, E-mail: shah.jyoti1@gmail.com; Kotnala, Ravinder K., E-mail: rkkotnala@nplindia.org, E-mail: rkkotnala@gmail.com [Multiferroic and Magnetics Laboratory, CSIR-National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India)

    2014-04-07

    Thin film of BaTiO{sub 3} doped with 0.1 at. % Cr (Cr:BTO) has been prepared by pulsed laser deposition technique. Film was deposited on Pt/SrTiO{sub 3} substrate at 500 °C in 50 mTorr Oxygen gas pressure using KrF (298 nm) laser. Polycrystalline growth of single phase Cr:BTO thin film has been confirmed by grazing angle X-ray diffraction. Cr:BTO film exhibited remnant polarization 6.4 μC/cm{sup 2} and 0.79 MV/cm coercivity. Magnetization measurement of Cr:BTO film showed magnetic moment 12 emu/cc. Formation of weakly magnetic domains has been captured by magnetic force microscopy. Theoretical impedance equation fitted to experimental data in Cole-Cole plot for thin film in presence of transverse magnetic field resolved the increase in grain capacitance from 4.58 × 10{sup −12} to 5.4 × 10{sup −11} F. Film exhibited high value 137 mV/cm-Oe magneto-electric (ME) coupling coefficient at room temperature. The high value of ME coupling obtained can reduce the typical processing steps involved in multilayer deposition to obtain multiferrocity in thin film. Barium titanate being best ferroelectric material has been tailored to be multiferroic by non ferromagnetic element, Cr, doping in thin film form opens an avenue for more stable and reliable spintronic material for low power magnetoelectric random excess memory applications.

  20. Structural and optical properties of chromium doped zinc oxide nanoparticles synthesized by sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, Syed Mohd. Adnan, E-mail: adiaks2004@yahoo.co.in [Department of Fundamental and Applied Sciences, Universiti Teknologi Petronas, Bandar Seri Iskandar, Perak (Malaysia); Irshad, Kashif, E-mail: alig.kashif@gmail.com [Department of Mechanical Engineering, Universiti Teknologi Petronas, Bandar Seri Iskandar, Perak (Malaysia); Soleimani, Hassan, E-mail: hassan.soleimani@petronas.com.my, E-mail: noorhana-yahya@petronas.com.my; Yahya, Noorhana, E-mail: hassan.soleimani@petronas.com.my, E-mail: noorhana-yahya@petronas.com.my

    2014-10-24

    Nanosized Cr-doped ZnO nano particles were synthesized by facile sol-gel auto combustion method. The structural and optical properties of Cr-doped ZnO nanoparticles have been investigated by XRD and UV-Vis spectroscopy at room temperature for 0% to 8% concentration. X-ray diffraction analysis reveals that the Cr-doped ZnO crystallizes in a single phase polycrystalline nature with wurtzite lattice. With every % of doping, the peaks are shifting scarcely and doping of Cr is possible up to 7%. After that, the last peak vanishes, that signifies its structure is transmuted from 8% doping. The average crystallite size decreases with increase in Cr concentration (i.e. 28.9 nm for 0% to 25.8 nm for 8%). The UV-Vis spectra of the nanoparticles betoken an incrementation in the band gap energy from 3.401, 3.415, 3.431, 3.437,3.453, 3.514,3.521, 3.530 and 3.538 eV respectively, for 0,1, 2, 3, 4, 5, 6, 7 and 8 % doping concentration.

  1. Order and disorder around Cr(3+) in chromium doped persistent luminescent AB2O4 spinels.

    Science.gov (United States)

    Basavaraju, Neelima; Priolkar, Kaustubh R; Gourier, Didier; Bessière, Aurélie; Viana, Bruno

    2015-04-28

    The X-ray absorption near edge structure (XANES) spectroscopy technique is used to better understand the charging and decharging processes of the persistent luminescence in the Cr(3+)doped AB2O4 spinels (A = Zn, Mg and B = Ga and Al) with low photon energy excitation by visible light. Cr K edge XANES spectra have been simulated for different near neighbour environments around the Cr(3+) recombination centres and compared with the experimental curve. In the Cr(3+):ZnGa2O4 compound, the Cr(3+) local structure corresponds mostly to that of a normal spinel (∼70%), while the rest comprises of a distorted octahedral environment arising from cationic site inversion and a contribution from chromium clustering. This local structure is considerably different in Cr(3+):MgGa2O4 and Cr(3+):ZnAl2O4, where, for both cases, chromium clustering represents the main contribution. The strong correlation between the intensity of persistent luminescence and the percentage of Cr in clusters leads us to infer that the presence of Cr clusters is responsible for the decrease of the intensity of the visible light induced persistent luminescence in the Cr(3+) doped AB2O4 spinels.

  2. Chromium doped TiO2 sputtered thin films synthesis, physical investigations and applications

    CERN Document Server

    Hajjaji, Anouar; Gaidi, Mounir; Bessais, Brahim; El Khakani, My Ali

    2014-01-01

    This book presents co-sputtered processes ways to produce chrome doped TiO2 thin films onto various substrates such as quartz, silicon and porous silicon. Emphasis is given on the link between the experimental preparation and physical characterization in terms of Cr content. Moreover, the structural, optical and optoelectronic investigations are emphasized throughout. The book explores the potencial applications of devices based on Cr doped TiO2 thin films as gas sensors and in photocatalysis and in the photovoltaic industry. Also, this book provides extensive leads into research literature, and each chapter contains details which aim to develop awareness of the subject and the methods used. The content presented here will be useful for graduate students as well as researchers in materials science, physics, chemistry and engineering.

  3. Manganese and chromium doping in atomically thin MoS2

    Science.gov (United States)

    Huang, Ce; Jin, Yibo; Wang, Weiyi; Tang, Lei; Song, Chaoyu; Xiu, Faxian

    2017-03-01

    Recently, two-dimensional materials have been attracting increasing attention because of their novel properties and promising applications. However, the impurity doping remains a significant challenge owing to the lack of the doping strategy in the atomically thin layers. Here we report on the chromium (Cr) and manganese (Mn) doping in atomically-thin {{{MoS}}}{{2}} crystals grown by chemical vapor deposition. The Cr/Mn doped {{{MoS}}}{{2}} samples are characterized by a peak at 1.76 and 1.79 eV in photoluminescence spectra, respectively, compared with the undoped one at 1.85 eV. The field-effect transistor (FET) devices based on the Mn doping show a higher threshold voltage than that of the pure {{{MoS}}}{{2}} while the Cr doping exhibits the opposite behavior. Importantly, the carrier concentration in these samples displays a remarkable difference arising from the doping effect, consistent with the evolution of the FET performance. The temperature-dependent conductivity measurements further demonstrate a large variation in activation energy. The successful incorporation of the Mn and Cr impurities into the monolayer {{{MoS}}}{{2}} paves the way towards the high Curie temperature two-dimensional dilute magnetic semiconductors. Project supported by the National Young 1000 Talent Plan, the Pujiang Talent Plan in Shanghai, the National Natural Science Foundation of China (Nos. 61322407, 11474058, 61674040), and the Chinese National Science Fund for Talent Training in Basic Science (No. J1103204).

  4. Photocatalytic Hydrogen Production over Chromium Doped Layered Perovskite Sr2TiO4.

    Science.gov (United States)

    Sun, Xiaoqin; Xie, Yinghao; Wu, Fangfang; Chen, Hongmei; Lv, Meilin; Ni, Shuang; Liu, Gang; Xu, Xiaoxiang

    2015-08-03

    Layered semiconductor photocatalysts have been found to exhibit promising performance levels, probably linked to their interlayer framework that facilitates separation of charge carriers and the reduction/oxidation reactions. Layered titanates, however, generally demonstrate activities under UV irradiation, and therein lies the strong desire to extend their activity into the visible light region. Here, we investigated a series of layered perovskite by doping Sr2TiO4 with Cr and/or La in the hope to improve their visible light responses. Their crystal structures and other physicochemical properties were systematically explored. Our results show that La and Cr can be successfully accommodated in the layered structure and Cr is an efficient dopant for the extension of visible light absorbance. Much enhanced photocatalytic hydrogen evolution was observed after doping and was found to be composition-dependent. The highest hydrogen production rate approaches 97.7 μmol/h for Sr2Ti0.95Cr0.05O4-δ under full range irradiation (λ ≥ 250 nm) and 17 μmol/h for Sr2Ti0.9Cr0.1O4-δ under visible light irradiation (λ ≥ 400 nm), corresponding to an apparent quantum efficiency of 0.16% and 0.05%, respectively. Theoretical calculation reveals that the improved optical and photocatalytic properties are owing to a newly formed spin-polarized valence band from Cr 3d orbitals. The decreased unit cell parameters, reduced band gaps as well as anisotropic properties of layered architectures are likely the reasons for a better activity. Nevertheless, instability of these compounds in the presence of moisture and CO2 was also noticed, suggesting that protective atmospheres are needed for the storage of these photocatalysts.

  5. Order and disorder around Cr$^{3+}$ in chromium doped persistent luminescence AB$_2$O$_4$ spinels

    OpenAIRE

    Basavaraju, Neelima; Priolkar, Kaustubh R.; Gourier, Didier; Bessière, Aurélie; Viana, Bruno

    2015-01-01

    X-ray absorption near edge structure (XANES) spectroscopy technique is used to better understand the charging and decharging processes of the persistent luminescence in the Cr$^{3+}$ doped AB$_2$O$_4$ spinels (A = Zn, Mg and B = Ga and Al) with low photon energy excitation by visible light. Cr K edge XANES spectra have been simulated for different near neighbour environments around the Cr$^{3+}$ recombination centres and compared with the experimental curve. In Cr$^{3+}$:ZnGa$_2$O$_4$ compoun...

  6. Chromium doping effects on structural and dielectric properties of Mn-Zn cobaltites

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, A. [School of Physics, Vigyan Bhavan, Devi Ahilya University, Khandwa Road Campus, Indore 452001 (India); Department of Physics, MEDICAPS Institute of Science and Technology, Pithampur 45331 (India); Dar, Mashkoor A., E-mail: darmashkoor.phst@gmail.com; Choudhary, P.; Varshney, Dinesh, E-mail: vdinesh33@rediffmail.com [School of Physics, Vigyan Bhavan, Devi Ahilya University, Khandwa Road Campus, Indore 452001 (India); Shah, P. [Amity Institute of Nanotechnology, Amity University, Sector 125, Noida 201303 (India)

    2016-05-06

    The effect of transition metal Cr{sup 2+} ion as a dopant of Zn{sup 2+} in Mn{sub 0.5}Zn{sub 0.5}Co{sub 2}O{sub 4} is investigated. Co-doped Mn{sub 0.5}Zn{sub 0.5-x}Cr{sub x}Co{sub 2}O{sub 4} (x = 0, 0.3 and 0.5) cobaltites were prepared by solid-state reaction route. X-ray powder diffraction (XRD) analysis reveals that the samples prepared are polycrystalline single-phase cubic spinel in structure having a space group Fd3m. An increase in average particle size observed with Cr{sup 2+} doping. However other structural parameters such as X-ray density, micro strain and dislocation density shows almost a similar decreasing trend with increase in Cr{sup 2+}. High value of permittivity ∼10{sup 5} is observed for the parent Mn{sub 0.5}Zn{sub 0.5}Co{sub 2}O{sub 4} and shows a substantial decrease with increase in the Cr{sup 2+} doping. Higher doping of Cr{sup 2+} also increases the dielectric loss and hence limits its technological importance. At lower frequencies ac conductivity has been found to increase with increase in Cr{sup 2+} content.

  7. Modeling removal of accumulated potassium from T-tubules by inward rectifier potassium channels

    NARCIS (Netherlands)

    Wallinga, W.; Vliek, M.; Wienk, E.D.; Alberink, M.J.; Ypey, D.L.; Ypey, D.L.

    1996-01-01

    The membrane models of Cannon et al. (1993) and Alberink et al. (1995) for mammalian skeletal muscle fibers are based upon Hodgkin-Huxley descriptions of sodium, potassium delayed rectifier and leak conductances and the capacitive current taking into account fast inactivation of sodium channels. Now

  8. Role of hemolysis in potassium release by iodinated contrast medium

    Energy Technology Data Exchange (ETDEWEB)

    Hayakawa, K.; Nakamura, T.; Shimizu, Y. [Department of Radiology, Kyoto City Hospital (Japan)

    1999-09-01

    It has been demonstrated that an iodinated contrast medium (CM) causes release of potassium into blood vessel lumina, resulting in an increase in serum potassium. The purpose of the present study was to assess whether this potassium release is due to hemolysis. Fresh human blood was mixed in vitro with CM at a ratio of 10:2. Potassium release rates were determined, and serum haptoglobin and free hemoglobin were measured after 30 min of exposure to CM. To compare the potassium release curve between CM exposure and true hemolysis induced by distilled water, fresh human blood was also mixed with distilled water. The level of serum haptoglobin decreased due to hemodilution. Changes in haptoglobin were not correlated with potassium release rates. The serum free hemoglobin level did not increase significantly, and there was no correlation between changes in the free hemoglobin level and the rate of potassium release. Hemolysis caused by water occurred instantaneously, whereas potassium release caused by CM was a slow response, which was linearly correlated with exposure time. Potassium release from blood cannot be explained by hemolysis. (orig.) With 4 figs., 4 tabs., 3 refs.

  9. Enhancement of Dielectric Breakdown Strength and Energy Conversion Efficiency of Niobate Glass-Ceramics by Sc2O3 Doping

    Science.gov (United States)

    Xiao, Shi; Xiu, Shaomei; Yang, Ke; Shen, Bo; Zhai, Jiwei

    2017-10-01

    Niobate glass-ceramics K2O-SrO-Nb2O5-B2O3-Al2O3-SiO2 (KSN-BAS) doped with different amounts of Sc2O3 have been prepared through a melt quenching/controlled crystallization method, and the influence of the Sc2O3 content on their phase composition, microstructure, dielectric performance, and charge-discharge properties investigated. X-ray powder diffraction results showed that the peak positions of the KSr2Nb5O15 phase shifted to higher angle and the glass-ceramic microstructures were significantly improved by Sc2O3 addition. Based on these results, 0.5 mol.% Sc2O3 doping was found to achieve remarkable enhancement in energy storage density, which reached 9.63 ± 0.39 J/cm3 at dielectric breakdown strength of 1450.38 ± 29.01 kV/cm with high conversion efficiency of ˜ 92.1%. For pulsed power applications, discharge speed of 17 ns and power density of 0.48 MW/cm3 were obtained in the glass-ceramic with 0.5 mol.% Sc2O3. These results could provide a new design strategy for high-performance dielectric capacitors.

  10. Characterization and analysis of finite-beam Bragg diffraction in a periodically poled lithium niobate electro-optic grating.

    Science.gov (United States)

    Chang, J W; Yau, H F; Chung, H P; Chang, W K; Chen, Y H

    2014-08-20

    We report the study, both theoretical and experimental, of the finite-beam Bragg diffraction behavior of an electro-optic (EO) volume grating made of a periodically poled lithium niobate (PPLN) crystal. When a Gaussian laser beam is used, the experimental observations show that the diffraction characteristics of the PPLN EO Bragg device, including the diffraction mode pattern and diffraction efficiency, are closely related to the interaction beam size and applied voltage, which cannot be modeled properly by a simplified theory using the plane-wave approximation. In this work, we have developed a theoretical model for describing the diffraction behavior of a PPLN EO Bragg device based on the coupled-wave theory with the aid of the plane-wave decomposition method. Specifically, we found that it is the angular distribution (or the dephasing bandwidth) of the plane wave elements decomposed from the incident Gaussian beam and grating strength that determine the Bragg coupling behavior of the device. We also identified some other electro-optically induced effects in the PPLN grating as an important mechanism in affecting the diffraction performance of the present device, especially at high working voltages.

  11. Noise Analysis of Second-Harmonic Generation in Undoped and MgO-Doped Periodically Poled Lithium Niobate

    Directory of Open Access Journals (Sweden)

    Yong Wang

    2008-01-01

    Full Text Available Noise characteristics of second-harmonic generation (SHG in periodically poled lithium niobate (PPLN using the quasiphase matching (QPM technique are analyzed experimentally. In the experiment, a0.78 μm second-harmonic (SH wave was generated when a 1.56 μm fundamental wave passed through a PPLN crystal (bulk or waveguide. The time-domain and frequency-domain noise characteristics of the fundamental and SH waves were analyzed. By using the pump-probe method, the noise characteristics of SHG were further analyzed when a visible light (532 nm and an infrared light (1090 nm copropagated with the fundamental light, respectively. The noise characterizations were also investigated at different temperatures. It is found that for the bulk and waveguide PPLN crystals, the SH wave has a higher relative noise level than the corresponding fundamental wave. For the same fundamental wave, the SH wave has lower noise in a bulk crystal than in a waveguide, and in MgO-doped PPLN than in undoped PPLN. The 532 nm irradiation can lead to higher noise in PPLN than the 1090 nm irradiation. In addition, increasing temperature of device can alleviate the problem of noise in conjunction with the photorefractive effect incurred by the irradiation light. This is more significant in undoped PPLN than in MgO-doped one.

  12. Temperature dependence of small polaron population decays in iron-doped lithium niobate by Monte Carlo simulations

    Science.gov (United States)

    Mhaouech, I.; Guilbert, L.

    2016-10-01

    The population decay of light-induced small polarons in iron-doped lithium niobate is simulated by a Monte-Carlo method on the basis of Holstein's theory. The model considers random walks of both bound polarons (NbLi4+) and free polarons (NbNb4+) ending to deep traps (FeLi3+). The thermokinetic interplay between polaron species is introduced by trapping and de-trapping rates at niobium antisites (NbLi). The decay of the NbLi4+ population proceeds by three possible channels: direct trapping at FeLi3+ sites, hopping on niobium antisites and hopping on Nb regular sites after conversion to the free state. Up to three regimes, each one reflecting the predominance of one of these processes, appear with different activation energies in the Arrhenius plots of the decay time. The influence of FeLi and NbLi concentrations on the transition temperatures is evidenced. For both polaron species, the length of the final hop (trapping length) is found much larger than the usual hopping length and decreases at rising temperature. This trap size effect is a natural consequence of Holstein's theory and may explain some unclear features of polaron-related light-induced phenomena, such as the temperature-dependent stretching exponent of light-induced absorption decays and the anomalous increase of the photoconductivity at high doping levels.

  13. Optical properties of Er{sup 3+}-doped strontium barium niobate nanocrystals obtained by thermal treatment in glass

    Energy Technology Data Exchange (ETDEWEB)

    Haro-Gonzalez, P. [Dep. of Fisica Fundamental Experimental, Electronica y Sistemas, Universidad de La Laguna Avda Astrofisico Franscisco Sanchez, 38206 La Laguna, S/C de Tenerife (Spain)], E-mail: patharo@ull.es; Lahoz, F. [Dep. of Fisica Fundamental Experimental, Electronica y Sistemas, Universidad de La Laguna Avda Astrofisico Franscisco Sanchez, 38206 La Laguna, S/C de Tenerife (Spain); Gonzalez-Platas, J. [Dep. of Fisica Fundamental II, Universidad de La Laguna, 38206 La Laguna, S/C de Tenerife (Spain); Caceres, J.M. [Dep. of Edafologia y Geologia, Universidad de La Laguna, 38206 La Laguna, S/C de Tenerife (Spain); Gonzalez-Perez, S. [Dep. of Fisica Fundamental Experimental, Electronica y Sistemas, Universidad de La Laguna Avda Astrofisico Franscisco Sanchez, 38206 La Laguna, S/C de Tenerife (Spain); Marrero-Lopez, D. [Dep. of Quimica Inorganica, Universidad de La Laguna, 38206 La Laguna, S/C de Tenerife (Spain); Capuj, N. [Dep. of Fisica Basica, Universidad de La Laguna, 38206 La Laguna, S/C de Tenerife (Spain); Martin, I.R. [Dep. of Fisica Fundamental Experimental, Electronica y Sistemas, Universidad de La Laguna Avda Astrofisico Franscisco Sanchez, 38206 La Laguna, S/C de Tenerife (Spain)

    2008-05-15

    Measurements of the optical properties of Er{sup 3+} ions in strontium barium niobate glass and glass ceramics have been carried out. The glasses have been fabricated using a melt-quenching method, and the glass ceramic samples have been obtained from the glass precursor by a thermal treatment. The ceramic samples formed by a glassy phase, and a crystalline phase contains nanocrystals of Sr{sub 1-x}Ba{sub x}Nb{sub 2}O{sub 6} (SBN) doped with Er{sup 3+} ions with a mean size of {approx}50 nm, as confirmed with XRD. Green up-conversion emission has been obtained under excitation at 800 nm, and the temporal evolution of this emission has been reported with the purpose of determining the involved up-conversion mechanism. These optical measures have confirmed that the Er{sup 3+} ions have been incorporated into the SBN matrix, after a thermal treatment, which produced an increment of the up-conversion efficiency.

  14. Structural analysis of lead magnesium niobate using synchrotron powder X-ray diffraction and the Rietveld method.

    Science.gov (United States)

    Bhakar, Ashok; Pandey, Adityanarayan H; Singh, M N; Upadhyay, Anuj; Sinha, A K; Gupta, S M; Ganguli, Tapas

    2016-06-01

    The room-temperature synchrotron powder X-ray diffraction pattern of the single phase perovskite lead magnesium niobate (PMN) has shown significant broadening in the q range ∼ 5-7 Å(-1) compared with standard LaB6 synchrotron powder X-ray diffraction data, taken under similar conditions. This broadening/asymmetry lies mainly towards the lower 2θ side of the Bragg peaks. Attempts to fit this data with the paraelectric cubic phase (Pm\\bar 3m) and the local rhombohedral phase (R3m) corresponding to polar nanoregions (PNRs) are made using the Rietveld method. Rietveld refinements show that neither cubic (Pm\\bar 3m) nor rhombohedral (R3m) symmetry can fit this XRD pattern satisfactorily. The two-phase refinement fits the experimental data satisfactorily and suggests that the weight percentage of the PNRs is approximately 12-16% at room temperature. The unit-cell volume of these rhombohedral PNRs is approximately 0.15% larger than that of the unit cell volume of the paraelectric cubic phase.

  15. Giant electric field tunable magnetic properties in a Co50Fe50/lead magnesium niobate-lead titanate multiferroic heterostructure

    Science.gov (United States)

    Yang, Wei-Gang; Morley, Nicola A.; Sharp, Joanne; Rainforth, W. Mark

    2015-08-01

    Co50Fe50/(0 1 1)-oriented lead magnesium niobate-lead titanate (PMN-PT) multiferroic (MF) heterostructures were fabricated by RF sputtering magnetic films onto PMN-PT substrates. The effect of magnetic layer thickness (30 nm to 100 nm) on the magnetoelectric (ME) coupling in the heterostructures was studied independently, due to the almost constant magnetostriction constant (λ = 40   ±   5 ppm) and similar as-grown magnetic anisotropies for all studied magnetic layer thicknesses. A record high remanence ratio (M r/M s) tunability of 95% has been demonstrated in the 65 nm Co50Fe50/PMN-PT heterostructure, corresponding to a large ME constant (α) of 2.5   ×   10-6 s m-1, when an external electric field (E-field) of 9 kV cm-1 was applied. Such an MF heterostructure provides considerable opportunities for E-field-controlled multifunctional devices.

  16. Surface plasmon polariton boosted photorefractive scattering in indium tin oxide coated Fe-doped lithium niobate slabs

    Science.gov (United States)

    Wang, Hao; Zhao, Hua; Li, Liang; Xu, Chao; Zhang, Jingwen

    2015-03-01

    To study the impact of surface plasmon polaritons on photorefractive effect, indium tin oxide (ITO) thin films were deposited onto Fe-doped lithium niobate (Fe: LiNbO3, LN) slabs. Striking scattering near surface normal (SNSN) of the slabs was observed, increasing with the incident angle of laser beam. The SNSN was so strong that it depleted the transmitted beam. Based on a tentative physical picture of photovoltaic (PV) effect induced electrostatic modification, the electron density of skin layer of ITO film was raised to such a level that surface plasmon polaritons (SPPs) were excited in LN/ITO interface via phase grating mediation. Consequently, the localized intensified electromagnetic fields exerted on the LN slabs and resulted in the SNSN. The impact of the SPPs and SNSN on the photorefractive effect can be seen from over 2.5 times SNSN enhancement in power and as high as 6.0 times boosting of the ratio of the SNSN power to the remaining transmitted one.

  17. Potassium Iodide ("KI"): Instructions to Make Potassium Iodide Solution for Use During a Nuclear Emergency (Liquid Form)

    Science.gov (United States)

    ... Radiation-Emitting Products Vaccines, Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products ... it Email Print Instructions to Make Potassium Iodide Solution for Use During a Nuclear ...

  18. Dialysate Potassium, Serum Potassium, Mortality, and Arrhythmia Events in Hemodialysis: Results From the Dialysis Outcomes and Practice Patterns Study (DOPPS).

    Science.gov (United States)

    Karaboyas, Angelo; Zee, Jarcy; Brunelli, Steven M; Usvyat, Len A; Weiner, Daniel E; Maddux, Franklin W; Nissenson, Allen R; Jadoul, Michel; Locatelli, Francesco; Winkelmayer, Wolfgang C; Port, Friedrich K; Robinson, Bruce M; Tentori, Francesca

    2017-02-01

    Sudden death is a leading cause of death in patients on maintenance hemodialysis therapy. During hemodialysis sessions, the gradient between serum and dialysate levels results in rapid electrolyte shifts, which may contribute to arrhythmias and sudden death. Controversies exist about the optimal electrolyte concentration in the dialysate; specifically, it is unclear whether patient outcomes differ among those treated with a dialysate potassium concentration of 3 mEq/L compared to 2 mEq/L. Prospective cohort study. 55,183 patients from 20 countries in the Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 1 to 5 (1996-2015). Dialysate potassium concentration at study entry. Cox regression was used to estimate the association between dialysate potassium concentration and both all-cause mortality and an arrhythmia composite outcome (arrhythmia-related hospitalization or sudden death), adjusting for potential confounders. During a median follow-up of 16.5 months, 24% of patients died and 7% had an arrhythmia composite outcome. No meaningful difference in clinical outcomes was observed for patients treated with a dialysate potassium concentration of 3 versus 2 mEq/L (adjusted HRs were 0.96 [95% CI, 0.91-1.01] for mortality and 0.98 [95% CI, 0.88-1.08] for arrhythmia composite). Results were similar across predialysis serum potassium levels. As in prior studies, higher serum potassium level was associated with adverse outcomes. However, dialysate potassium concentration had only minimal impact on serum potassium level measured predialysis (+0.09 [95% CI, 0.05-0.14] mEq/L serum potassium per 1 mEq/L greater dialysate potassium concentration). Data were not available for delivered (vs prescribed) dialysate potassium concentration and postdialysis serum potassium level; possible unmeasured confounding. In combination, these results suggest that approaches other than altering dialysate potassium concentration (eg, education on dietary potassium sources and

  19. Changes in erythrocyte contents of potassium, sodium and magnesium and Na, K-pump activity after the administration of potassium and magnesium salts.

    Science.gov (United States)

    Sriboonlue, Pote; Jaipakdee, Sudjai; Jirakulsomchok, Dusit; Mairiang, Eimorn; Tosukhowong, Piyaratana; Prasongwatana, Vitoon; Savok, Sompong

    2004-12-01

    Low potassium and magnesium status and decreased Na, K-pump activity is an endemic condition among rural Northeast Thais. The authors examined the effect of supplementing potassium and magnesium on erythrocyte potassium, sodium and magnesium content and on Na, K-pump activity. Rural Northeast Thai renal stone patients (62) were recruited, divided into four groups and supplemented for one month with potassium chloride (Group1, n = 16), potassium-sodium citrate (Group2, n = 15), chelated magnesium (Group 3, n =16) and potassium-magnesium citrate (Group 4, n =15) in order to achieve 40 mmol potassium, 10 mmol magnesium and 60 mmol citrate daily. After supplementation with potassium (Groups 1, 2 and 4), plasma potassium and Na, K-pump activity rose significantly in Groups 1, 2 and 4, but erythrocyte potassium rose only in Groups 2 and 4. When supplementing elemental magnesium (Groups 3 and 4), the chelated magnesium caused a significant increase in plasma potassium, erythrocyte potassium, sodium and magnesium without a significant increase in Na, K-pump activity. By contrast, potassium-magnesium citrate caused a significant increase in erythrocyte potassium and magnesium and Na, K-pump activity, but depressed erythrocyte sodium. These results suggest the forms of potassium and /or magnesium salts being supplemented should be considered because they affect erythrocyte potassium, sodium and magnesium content and Na, K-pump activity differently.

  20. Potassium cycling and losses in grassland systems : a review

    NARCIS (Netherlands)

    Kayser, M; Isselstein, J

    Cycling of potassium in grassland systems has received relatively little attention in research and practice in recent years. Balanced nutrient systems require consideration of nutrients other than nitrogen (N). Potassium (K) is needed in large amounts and is closely related to N nutrition. In

  1. A novel potassium deficiency-induced stimulon in Anabaena torulosa

    Indian Academy of Sciences (India)

    These proteins contrast with the dinitrogenase reductase of A. torulosa and the glycine betaine-binding protein of E. coli, both of which were osmo-induced to a higher level in potassium-supplemented conditions. The data demonstrate the occurrence of novel potassium deficiency-induced stimulons and a wider role of K+ in ...

  2. Sodium and potassium concentrations in floral nectars in relation to ...

    African Journals Online (AJOL)

    Sodium and potassium concentrations have been measured in nectar from a variety of flowering plants visited by honey bees (Apis mellifera capensis). In 18 plant species the mean sodium concentration was 9,8 ± 1,4 mmol (± S.E.), and the mean potassium concentration was 18,7 ± 4,3 mmol. These results are compared ...

  3. Sodium and potassium concentrations in floral nectars in relation to ...

    African Journals Online (AJOL)

    1989-08-03

    Aug 3, 1989 ... Sodium and potassium concentrations have been measured in nectar from a variety of flowering plants visited by honey bees fApis me/litera capensis). In 18 plant species the mean sodium concentration was 9,8 ± 1,4 mmol (± S.E.), and the mean potassium concentration was 18,7 ± 4,3 mmol.

  4. Potassium Concentration in Blood of Brazilian Athletes Using NAA

    Science.gov (United States)

    Kovacs, Luciana; Zamboni, Cibele B.; Lourenço, Thiago F.; Nunes, Lázaro A. S.; Macedo, Denise V.

    2011-08-01

    In this study the potassium levels in blood were determined in male athletes, age 18 to 26 years, before, during and after the tread mill exercise protocol using Neutron Activation Analyses (NAA). These data are important to check the potassium imbalance in blood during the period of competition preparation.

  5. Haemoglobin and potassium polymorphism in agro-pastoral goats ...

    African Journals Online (AJOL)

    The Chi-square test revealed that the population of goats in the study area was in Hardy- Weinberg equilibrium. The gene frequencies of potassium polymorphism were 0.844 and 0.156 for high (HK) and low potassium (LK) types, respectively. The genotypic frequencies were 0.91 for HK and 0.01 for LK in the overall ...

  6. Evaluation of in vitro antifungal activity of potassium bicarbonate on ...

    African Journals Online (AJOL)

    The effect of increased concentrations of potassium bicarbonate (KHCO3) as a possible alternative to synthetic fungicides for controlling Rhizoctonia solani AG 4 HG-I and Sclerotinia sclerotiorum was evaluated in vitro, in this study. In addition, the effect of potassium bicarbonate on Trichoderma sp., a natural antagonist on ...

  7. Relationship between serum total magnesium and serum potassium ...

    African Journals Online (AJOL)

    Introduction: Potassium and magnesium are the two most abundant intra cellular cations. They play pivotal roles in many essential biological processes. Deficiencies of these electrolytes are of clinical importance in hospitalised patients. Aim: To determine the relationship between serum total magnesium and potassium ...

  8. Potassium silicate-zinc oxide solution for metal finishes

    Science.gov (United States)

    Schutt, J. B.

    1970-01-01

    Examples of zinc dust formulations, which are not subject to cracking or crazing, are fire retardant, and have high adhesive qualities, are listed. The potassium silicate in these formulations has mol ratios of dissolved silica potassium oxide in the range 4.8 to 1 - 5.3 to 1.

  9. Potassium bromate content of some baked breads sold in Kano ...

    African Journals Online (AJOL)

    Background: Potassium bromate is an additive used by some bakers to make the bread rise rapidly, create a good texture in the finished product and to give bulkiness to the dough. Objective: The main objective of this work was to assess the potassium bromate residues of some baked breads sold in some selected local ...

  10. Determination and comparison of vitamin C, calcium and potassium ...

    African Journals Online (AJOL)

    Vitamin C content was determined by 2,6-dichloroindophenol titrimetric method while calcium and potassium were determined by atomic absorption spectroscopy. Results from the study showed inconsistent pattern with respect to vitamin C, calcium and potassium contents in the conventionally and organically grown ...

  11. 40 CFR 721.10021 - Magnesium potassium titanium oxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Magnesium potassium titanium oxide... Specific Chemical Substances § 721.10021 Magnesium potassium titanium oxide. (a) Chemical substance and... titanium oxide (PMN P-01-764; CAS No. 39290-90-9) is subject to reporting under this section for the...

  12. Potassium Bromate Content of Bread Produced in Sokoto Metropolis ...

    African Journals Online (AJOL)

    Fifteen different bread samples were randomly collected from various local bakeries located in Sokoto metropolis. The samples were analysed for presence and quantity of potassium bromate. All the samples were analysed using the redox titrimetric method for the detection of potassium bromate. All the samples contained ...

  13. Accidental Potassium Bromate Poisoning Causing Acute Renal Failure

    OpenAIRE

    Adeleke SI; Asani MO

    2009-01-01

    Accidental poisoning is common in children. Potassium bromate is commonly used additive and raising agent in many edibles especially bread which is a staple food in Nigeria. This communication is that of an unusual case of acute renal failure following accidental ingestion of potassium bromate tablets.

  14. Top-dressing of Potassium Fertilizers on Safflower

    Directory of Open Access Journals (Sweden)

    Neginsadat Amir Khalili

    2016-10-01

    Full Text Available To determine the effects of potassium foliar application (with two levels, use and non-use from potassium sulphate source and top-dressing application of potassium fertilizer (with two levels, use and non-use from potassium chloride source on number of seeds per capitulum, number of side branch per plant, seed yield, seed oil content, oil yield, seed to coat ratio, plant height and shoot dry weight in three safflower, genotypes including KW.2, Padideh and Goldasht a factorial experiment based on the randomized complete block design (RCBD with three replications, was conducted during 2013 growing season at the Agricultural Research Center of Semnan province (Shahroud. Results showed that the highest average of number of seeds per capitulum (28.70, number of side branch per plant (17.83 and seed to coat ratio (1.47 were found in KW.2 genotype. The highest seed yield (2627.7 kg/ha and oil yield (1350.5 kg/ha were found from potassium sulphate foliar application in Padideh and KW.2 genotypes respectively. The interaction effect of genotype × potassium foliar application was significant for seed and oil yields. In conclusion, it was determined that potassium sulphate foliar application has better impacts on seed and oil yield of safflower genotypes than potassium top-dressing application.

  15. Crystal structure of the sodium-potassium pump

    DEFF Research Database (Denmark)

    Morth, J Preben; Pedersen, Bjørn Panyella; Toustrup-Jensen, Mads S

    2007-01-01

    The Na+,K+-ATPase generates electrochemical gradients for sodium and potassium that are vital to animal cells, exchanging three sodium ions for two potassium ions across the plasma membrane during each cycle of ATP hydrolysis. Here we present the X-ray crystal structure at 3.5 A resolution of the...

  16. Accidental Potassium Bromate Poisoning Causing Acute Renal Failure

    Directory of Open Access Journals (Sweden)

    Adeleke SI

    2009-05-01

    Full Text Available Accidental poisoning is common in children. Potassium bromate is commonly used additive and raising agent in many edibles especially bread which is a staple food in Nigeria. This communication is that of an unusual case of acute renal failure following accidental ingestion of potassium bromate tablets

  17. Effects of Nitrogen, Potassium and Weed Interference on Yield of ...

    African Journals Online (AJOL)

    Parameters studied included bulb weight (g), bulb diameter (cm) and bulb heights (cm). The result indicated significant (P<0.05) effect of potassium, nitrogen and weed interference on the yield of onion. Highest bulb yield was obtained with 250 kg/ha potassium, 150 kg/ha nitrogen and the 4 WAT weeding regime. No bulbs ...

  18. The Effect Of Potassium Bromate On Some Haematological ...

    African Journals Online (AJOL)

    Summary: Potassium bromate used widely in foods has been associated with various complications in humans. However there is paucity of literature on adverse effects on haematological parameters. Thus we decided to carry out an experimental study to determine the effects of potassium bromate on some blood indices ...

  19. Extractability of Potassium from Some Organic Manures in Aqueous ...

    African Journals Online (AJOL)

    The effect of pH, time and concentration on the extractability of potassium from five types of organic manures (cow dung, local chickens, duck and commercial chickens, faeces on bedded and unbedded floor) were studied. Experiments were conducted in water at 40oC. Cumulative extraction curves of potassium resulting ...

  20. Acute toxicity studies of potassium permanganate in Swiss albino mice

    African Journals Online (AJOL)

    Acute toxicity study of potassium permanganate was carried out in Swiss albino mice. Potassium permanganate was administered at dose rate of 0.0, 500, 1000, 1500, 2000, 2500, 3000 and 3500mg/kg body weight to groups 1, 2, 3, 4, 5, 6, 7 and 8, ten per group for LD50 determination. The dead animals were posted for ...

  1. 75 FR 76016 - Determination That AUGMENTIN `125' (Amoxicillin; Clavulanate Potassium) Chewable Tablet and Six...

    Science.gov (United States)

    2010-12-07

    ... HUMAN SERVICES Food and Drug Administration Determination That AUGMENTIN `125' (Amoxicillin; Clavulanate Potassium) Chewable Tablet and Six Other AUGMENTIN (Amoxicillin; Clavulanate Potassium) Drug Products Were... (amoxicillin; clavulanate potassium) drug products listed in this notice were not withdrawn from sale for...

  2. Potassium bromide, KBr/ ε: New Force Field

    Science.gov (United States)

    Fuentes-Azcatl, Raúl; Barbosa, Marcia C.

    2018-02-01

    We propose a new force field for the Potassium Bromide, the KBr/ ε. The crystal density and structure, as well as, the density, the viscosity and the dielectric constant of the solution in water were computed and compared with the experiments and other atomistic models. Next, the transferability of the KBr/ ε and of the NaCl/ ε models is verified by creating the KCl/ ε and the NaBr/ ε models. The strategy was to employ the same parameters obtained for the NaCl/ ε and for the KBr/ ε force fields for the building up of the KCl/ ε and the NaBr/ ε models . The thermodynamic and dynamic properties of these two new models were compared with the experimental

  3. Potassium Capture by Kaolin, Part 1: KOH

    DEFF Research Database (Denmark)

    Wang, Guoliang; Jensen, Peter Arendt; Wu, Hao

    2018-01-01

    The reaction of gaseous KOH with kaolin and mullite powder under suspension-fired conditions was studied by entrained flow reactor (EFR) experiments. A water-based slurry containing kaolin/mullite and KOH was fed into the reactor and the reacted solid samples were analyzed to quantify the K.......47 μm) and fine(D50 = 3.51 μm) kaolin powder at1100 and 1300 °C. The difference was less significant at 900°C. Mullite generated from kaolin captured KOH less effectively than kaolin at temperatures below 1100 °C. However, at 1300 and1450 °C, the amount of potassium captured by mullite became comparable...

  4. Effects of potassium peroxydiphosphate on bone resorption.

    Science.gov (United States)

    Gaffar, A; Alander, C B; Raisz, L G

    1991-10-01

    Potassium peroxydiphosphate (KPDP) is a slowly hydrolyzed pyrophosphate analog that can release hydrogen peroxide during hydrolysis. We tested its effects on the resorption of cultured fetal rat long bones as measured by the release of previously incorporated 45Ca, both by direct addition of KPDP to the medium and after preincubation of KPDP with large-molecular-weight resorbing factors followed by dialysis to reduce the KPDP concentration. With direct addition, KPDP at a concentration of 1 mM could inhibit the resortive response to bacterial lipopolysaccharide (LPS), parathyroid hormone (PTH), prostaglandin E2 (PGE2), and mouse recombinant interleukin-1 (mrIL-1). The response to LPS was partially inhibited at 0.3 mM KPDP. Control resorption in the absence of stimulators was also inhibited. Potassium pyrophosphate at 1 mM was less effective as an inhibitor of bone resorption. The inhibitory effects of KPDP did not appear to be due entirely to nonspecific toxicity since partial recovery occurred after it was removed. There was no significant decrease in [3H]thymidine or [3H]proline incorporation into bones incubated with KPDP at 1 mM for 5 days, but [3H]proline incorporation was decreased at 24 h, suggesting that KPDP may have a general inhibitory effect on bone cells. When media with and without stimulators of resorption were incubated overnight at 4 degrees C with KPDP at 5.8 mM and then dialyzed to bring the concentration to below 0.3 mM, the bone-resorbing activity of PTH, LPS, and mrIL-1 was completely lost. This may have been due to the slow release of hydrogen peroxide; however, preincubation with equimolar concentrations of H2O3 caused only partial inactivation of PTH and LPS. LPS.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Bioinspired Artificial Sodium and Potassium Ion Channels.

    Science.gov (United States)

    Rodríguez-Vázquez, Nuria; Fuertes, Alberto; Amorín, Manuel; Granja, Juan R

    2016-01-01

    In Nature, all biological systems present a high level of compartmentalization in order to carry out a wide variety of functions in a very specific way. Hence, they need ways to be connected with the environment for communication, homeostasis equilibrium, nutrition, waste elimination, etc. The biological membranes carry out these functions; they consist of physical insulating barriers constituted mainly by phospholipids. These amphipathic molecules spontaneously aggregate in water to form bilayers in which the polar groups are exposed to the aqueous media while the non-polar chains self-organize by aggregating to each other to stay away from the aqueous media. The insulating properties of membranes are due to the formation of a hydrophobic bilayer covered at both sides by the hydrophilic phosphate groups. Thus, lipophilic molecules can permeate the membrane freely, while the small charged or very hydrophilic molecules require the assistance of other membrane components in order to overcome the energetic cost implied in crossing the non-polar region of the bilayer. Most of the large polar species (such as oligosaccharides, polypeptides or nucleic acids) cross into and out of the cell via endocytosis and exocytosis, respectively. Nature has created a series of systems (carriers and pores) in order to control the balance of small hydrophilic molecules and ions. The most important structures to achieve these goals are the ionophoric proteins that include the channel proteins, such as the sodium and potassium channels, and ionic transporters, including the sodium/potassium pumps or calcium/sodium exchangers among others. Inspired by these, scientists have created non-natural synthetic transporting structures to mimic the natural systems. The progress in the last years has been remarkable regarding the efficient transport of Na(+) and K(+) ions, despite the fact that the selectivity and the ON/OFF state of the non-natural systems remain a present and future challenge.

  6. Amiodarone Inhibits Apamin-Sensitive Potassium Currents

    Science.gov (United States)

    Turker, Isik; Yu, Chih-Chieh; Chang, Po-Cheng; Chen, Zhenhui; Sohma, Yoshiro; Lin, Shien-Fong; Chen, Peng-Sheng; Ai, Tomohiko

    2013-01-01

    Background Apamin sensitive potassium current (IKAS), carried by the type 2 small conductance Ca2+-activated potassium (SK2) channels, plays an important role in post-shock action potential duration (APD) shortening and recurrent spontaneous ventricular fibrillation (VF) in failing ventricles. Objective To test the hypothesis that amiodarone inhibits IKAS in human embryonic kidney 293 (HEK-293) cells. Methods We used the patch-clamp technique to study IKAS in HEK-293 cells transiently expressing human SK2 before and after amiodarone administration. Results Amiodarone inhibited IKAS in a dose-dependent manner (IC50, 2.67±0.25 µM with 1 µM intrapipette Ca2+). Maximal inhibition was observed with 50 µM amiodarone which inhibited 85.6±3.1% of IKAS induced with 1 µM intrapipette Ca2+ (n = 3). IKAS inhibition by amiodarone was not voltage-dependent, but was Ca2+-dependent: 30 µM amiodarone inhibited 81.5±1.9% of IKAS induced with 1 µM Ca2+ (n = 4), and 16.4±4.9% with 250 nM Ca2+ (n = 5). Desethylamiodarone, a major metabolite of amiodarone, also exerts voltage-independent but Ca2+ dependent inhibition of IKAS. Conclusion Both amiodarone and desethylamiodarone inhibit IKAS at therapeutic concentrations. The inhibition is independent of time and voltage, but is dependent on the intracellular Ca2+ concentration. SK2 current inhibition may in part underlie amiodarone's effects in preventing electrical storm in failing ventricles. PMID:23922993

  7. Amiodarone inhibits apamin-sensitive potassium currents.

    Directory of Open Access Journals (Sweden)

    Isik Turker

    Full Text Available Apamin sensitive potassium current (I KAS, carried by the type 2 small conductance Ca(2+-activated potassium (SK2 channels, plays an important role in post-shock action potential duration (APD shortening and recurrent spontaneous ventricular fibrillation (VF in failing ventricles.To test the hypothesis that amiodarone inhibits I KAS in human embryonic kidney 293 (HEK-293 cells.We used the patch-clamp technique to study I KAS in HEK-293 cells transiently expressing human SK2 before and after amiodarone administration.Amiodarone inhibited IKAS in a dose-dependent manner (IC50, 2.67 ± 0.25 µM with 1 µM intrapipette Ca(2+. Maximal inhibition was observed with 50 µM amiodarone which inhibited 85.6 ± 3.1% of IKAS induced with 1 µM intrapipette Ca(2+ (n = 3. IKAS inhibition by amiodarone was not voltage-dependent, but was Ca(2+-dependent: 30 µM amiodarone inhibited 81.5±1.9% of I KAS induced with 1 µM Ca(2+ (n = 4, and 16.4±4.9% with 250 nM Ca(2+ (n = 5. Desethylamiodarone, a major metabolite of amiodarone, also exerts voltage-independent but Ca(2+ dependent inhibition of I KAS.Both amiodarone and desethylamiodarone inhibit I KAS at therapeutic concentrations. The inhibition is independent of time and voltage, but is dependent on the intracellular Ca(2+ concentration. SK2 current inhibition may in part underlie amiodarone's effects in preventing electrical storm in failing ventricles.

  8. Offset-Free Gigahertz Midinfrared Frequency Comb Based on Optical Parametric Amplification in a Periodically Poled Lithium Niobate Waveguide

    Science.gov (United States)

    Mayer, A. S.; Phillips, C. R.; Langrock, C.; Klenner, A.; Johnson, A. R.; Luke, K.; Okawachi, Y.; Lipson, M.; Gaeta, A. L.; Fejer, M. M.; Keller, U.

    2016-11-01

    We report the generation of an optical-frequency comb in the midinfrared region with 1-GHz comb-line spacing and no offset with respect to absolute-zero frequency. This comb is tunable from 2.5 to 4.2 μ m and covers a critical spectral region for important environmental and industrial applications, such as molecular spectroscopy of trace gases. We obtain such a comb using a highly efficient frequency conversion of a near-infrared frequency comb. The latter is based on a compact diode-pumped semiconductor saturable absorber mirror-mode-locked ytterbium-doped calcium-aluminum gadolynate (Yb:CALGO) laser operating at 1 μ m . The frequency-conversion process is based on optical parametric amplification (OPA) in a periodically poled lithium niobate (PPLN) chip containing buried waveguides fabricated by reverse proton exchange. The laser with a repetition rate of 1 GHz is the only active element of the system. It provides the pump pulses for the OPA process as well as seed photons in the range of 1.4 - 1.8 μ m via supercontinuum generation in a silicon-nitride (Si3 N4 ) waveguide. Both the PPLN and Si3 N4 waveguides represent particularly suitable platforms for low-energy nonlinear interactions; they allow for mid-IR comb powers per comb line at the microwatt level and signal amplification levels up to 35 dB, with 2 orders of magnitude less pulse energy than reported in OPA systems using bulk devices. Based on numerical simulations, we explain how high amplification can be achieved at low energy using the interplay between mode confinement and a favorable group-velocity mismatch configuration where the mid-IR pulse moves at the same velocity as the pump.

  9. Synthesis and characterization of Ca{sup 2+} substituted barium niobate nanopaticles for photocatalytic and luminescence applications

    Energy Technology Data Exchange (ETDEWEB)

    Dudhe, C.M. [Department of Physics, Government Institute of science, Nagpur 440001 (India); Nagdeote, S.B. [Department of Physics, Amolakchand Mahavidhyalaya, Yavatmal 445001 (India); Palikundwar, U.A., E-mail: chandraguptadudhe@gmail.com [Department of Physics, R. T. M. Nagpur University, Nagpur 440033 (India)

    2016-09-15

    Highlights: • Nanoparticles of Ca{sup 2+} (30 mol%) substituted BaNb{sub 2}O{sub 6} were synthesized. • Ca{sup 2+} ions occupy newer 8d Wyckoff positions rather than 4c. • Self-activated photoluminescence was observed. • Excellent H{sub 2} generation tendency from pure water under UV light was also observed. - Abstract: Ca{sup 2+} substituted barium niobate i.e. Ca{sub x}Ba{sub 1-x}Nb{sub 2}O{sub 6} (x = 0.3) compound in nanoparticles form was synthesized by a simple co-precipitation method for the first time and its structural characterization has been done by using powder X-ray diffraction data. Other characterizations were done by using transmission electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy. It was found that the Ca{sub x}Ba{sub 1-x}Nb{sub 2}O{sub 6} (x = 0.3) compound stabilizes in the orthorhombic phase (Pbcn space group) with the lattice parameters a = 14.984 Å, b = 5.761 Å and c = 5.216 Å. A representative TEM image shows the irregular sphere like morphology of the synthesized particles with the size ranging from 70 to 120 nm. The optical band gap energy was found to be 3.74 eV. It was observed that the synthesized nanoparticles exhibit excellent H{sub 2} evolution tendency and self–activated photoluminescence under the excitation of UV light. These activities were assigned to the nanocrystalline nature of the synthesized material.

  10. Reversible redox processes of poly(anilines) in layered semiconductor niobate films under alternate UV-vis light illumination.

    Science.gov (United States)

    Inui, Yoshihisa; Yui, Tatsuto; Itoh, Toshio; Higuchi, Kimitaka; Seki, Takahiro; Takagi, Katsuhiko

    2007-10-25

    The synthesis of polyaniline (PANI) with semiconducting layered niobate (NbO) to form PANI/NbO hybrid materials and their reversible color change under a unique redox process under the influence of UV and/or visible light have been investigated. The in-situ polymerization of anilinium chlorides (ANI) packed in a regular orientation in a bilayer structure within the NbO interlayers led to PANI/NbO hybrid powders by heat treatment using (NH(4))(2)S(2)O(8) as the catalyst. The resulting PANI of these hybrids showed the characteristics of a fully oxidized quinoid form, i.e., pernigranine (PG). The PANI/NbO suspension in H(2)O was cast on a glass substrate to form a PANI/NbO film after evaporation of the water with a good parallel orientation of the NbO layers against the glass substrate. Upon UV light irradiation in the presence of a reductant such as MeOH, the violet-colored PANI (PG) polymers within the NbO interlayers were reduced by the NbO-induced photocatalytic reactions and led to a colorless PANI, i.e., leucoemeraldine (LE). Moreover, the resulting colorless PANI/NbO films reverted back to a blue-colored PANI, i.e., emeraldine (EM), due to oxidation by the surrounding O(2) gas. The PANI/NbO hybrid films were able to retain repetitive and reversible photoinduced patterning for over 50 cycles under such alternate UV and visible light irradiation.

  11. Changes in potassium pools in Paraná soils under successive cropping and potassium fertilization

    Directory of Open Access Journals (Sweden)

    Fabio Steiner

    2015-12-01

    Full Text Available The changes in soil potassium pools under intense cropping and fertilized with potash fertilizer are still little known to the soils of Paraná State. The effects of potassium fertilization and successive cropping on changes in K pools in different soils of Paraná, Brazil, were investigated in this study. Twelve soil samples, collected from the upper layer 0–0.20 m, were fertilized or not with K and subjected to six successive cropping (i.e., soybean, pearl millet, wheat, common beans, soybean and maize. All the crops were grown for 45 days, and at the end of the second, fourth and sixth cropping, the soil from each pot was sampled to determination of the total K, non-exchangeable K, exchangeable K and solution K. The result showed that the soil potassium pools varied widely. Total K concentration ranged from 547 to 15,563 mg kg–1 (4,714 mg kg–1, on average. On the average, structural K, non-exchangeable K, exchangeable K and solution K of the soils constituted 84.0, 11.3, 4.6 and 0.1% of the total K, respectively. Soils differ in the ability to supply potassium to the plants in the short to medium term, due to the wide range of parent material and the degree of soil weathering. When the soils were not fertilized with K, the successive cropping of plants resulted in a continuous process of depletion of non-exchangeable K and exchangeable K pools; however, this depletion was less pronounced in soils with higher potential buffer capacity of K. The concentrations of K non-exchangeable and exchangeable K were increased with the addition of potassium fertilizers, indicating the occurrence of K fixation in soil. After the second cropping, the soil exchangeable K levels remained constant with values of 141 and 36 mg kg–1, respectively, with and without the addition of K fertilizer, reflecting in establishing of a new dynamic equilibrium of K in the soil.

  12. Potassium Silicate Foliar Fertilizer Grade from Geothermal Sludge and Pyrophyllite

    Directory of Open Access Journals (Sweden)

    Muljani Srie

    2016-01-01

    Full Text Available Potassium silicate fertilizer grade were successfully produced by direct fusion of silica (SiO2 and potasium (KOH and K2CO3 in furnaces at temperatures up to melting point of mixture. The geothermal sludge (98% SiO2 and the pyrophyllite (95% SiO2 were used as silica sources. The purposes of the study was to synthesise potassium silicate fertilizer grade having solids concentrations in the range of 31-37% K2O, and silica in the range of 48-54% SiO2. The weight ratio of silicon dioxide/potasium solid being 1:1 to 5:1. Silica from geothermal sludge is amorphous, whereas pyrophylite is crystalline phase. The results showed that the amount of raw materials needed to get the appropriate molar ratio of potassium silicate fertilizer grade are different, as well as the fusion temperature of the furnace. Potassium silicate prepared from potassium hydroxide and geothermal sludge produced a low molar ratio (2.5: 1 to 3: 1. The potassium required quite small (4:1 in weight ratio, and on a fusion temperature of about 900 °C. Meanwhile, the potassium silicate prepared from pyrophyllite produced a high molar ratio (1.4 - 9.4 and on a fusion temperature of about 1350 °C, so that potassium needed large enough to meet the required molar ratio for the fertilizer grade. The product potassium silicate solid is amorphous with a little trace of crystalline.

  13. Effects of Long-term Fertilization on Potassium Fixation Capacity in Brown Soil

    Science.gov (United States)

    Li, Na; Guo, Chunlei; Wang, Yue; Gao, Tianyi; Yang, Jinfeng; Han, Xiaori

    2018-01-01

    This study concentrated on the research of features of fixation. The objective of this study was to provide theoretical foundation of rational application of potassium fertilizer along with improving fertilizer availability ratio. A 32 years long-term experiment was conducted to evaluate the effects of fertilizer application on potassium changes and the factors affecting K fixation on brown soil by simulation in laboratory. When the concentration of exogenous potassium was in range of 400∼4000 mg·kg-1, potassium fixation capacity increased along with the rise of concentration of exogenous potassium, whereas K fixation rate reduced; Compared with no-potassium fertilizer, application of potassium fertilizer and organic fertilizer reduced soil potassium fixation capacity. Potassium rate and fixation-release of potassium character in soil should be taken into comprehensive consideration for rational fertilization to maintain or improve soil fertility for increasing potassium fertilizers efficiency in agriculture.

  14. Substitution mechanisms and location of Co2+ ions in congruent and stoichiometric lithium niobate crystals derived from electron paramagnetic resonance data

    Science.gov (United States)

    Grachev, V. G.; Hansen, K.; Meyer, M.; Kokanyan, E. P.; Malovichko, G. I.

    2017-03-01

    Electron paramagnetic resonance (EPR) spectra and their angular dependencies were measured for Co2+ trace impurities in stoichiometric samples of lithium niobate doped with rhodium. It was found that Co2+ substitutes for Li+ in the dominant axial center (CoLi) and that the principal substitution mechanism in stoichiometric lithium niobate is 4Co2+ ↔ 3Li+  +  Nb5+. The four Co2+ ions can occupy the nearest possible cation sites by occupying a Nb site and its three nearest-neighbor Li sites, creating a trigonal pyramid with C3 symmetry, as well as non-neighboring sites (e.g. a CoNb-CoLi pair at the nearest sites on the C3 axis with two nearby isolated single Co2+ ions substituted for Li+). In congruent crystals and samples with Li content enriched by vapor transport equilibrium treatment the excess charge of the Co2+ centers is compensated by lithium vacancies located rather far from the Co2+ ions for the dominant axial center or in the nearest neighborhood for low-symmetry satellite centers (the Co2+ ↔ 2Li+ substitution mechanism). The use of exact numerical diagonalization of the spin-Hamiltonian matrices explains all the details of the EPR spectra and gives a value for hyperfine interaction A || that is several times smaller than that obtained using perturbation formulae. The refined values of A and g-tensor components can be used as reliable cornerstones for ab initio and cluster calculations.

  15. Irradiation-induced modification of the material parameters in magnesium-doped lithium niobate; Bestrahlungsinduzierte Modifikation der Materialparameter in Magnesiumdotiertem Lithiumniobat

    Energy Technology Data Exchange (ETDEWEB)

    Jentjens, Lena

    2010-07-01

    In the framework of this thesis the material properties of lithium niobate are directedly influenced by the irradiation with {sup 3}He ions with an energy of 40 MeV. In the first part the irradiation-induced material changes are intensively studied. Long-time stable changes of the refractive index are measured in the range of up to 6.10{sup -3}, which depend on the radiation dose and exhibit until now no saturation behaviour. Accompanied is this change by an also dose-dependent deformation as well as a brownish change of color of the crystals. Furthermore a by several orders of magnitude increased electrical dark- and photoconductivity, which depends on the ion dose and exhibits until now also no saturation behaviour. An effect independent on the ion dose is the reduction of the coercive field strength by about 10%. Furthermore it was stated the quantity of the effects not only depends on the absolute dose, but also on the irradiation direction in view of the crystallographic c-axis. The second part of this thesis deals with the generation of microscopic structures in lithium niobate. By an ion microbeam respectively a shiftable slit aperture the fabrication of refractive-index gratings is pursued. Grating with periodicity lengths in the range of 12-160 {mu}m could until now be detected and promise in comparison with photorefractive gratings the advance of larger stability.

  16. Liquid crystalline nanosheet colloids with controlled particle size obtained by exfoliating single crystal of layered niobate k(4)nb(6)o(17).

    Science.gov (United States)

    Miyamoto, Nobuyoshi; Nakato, Teruyuki

    2004-05-20

    Colloidally dispersed niobate nanosheets with the thickness of 1.8 nm and controlled mean lateral sizes of 0.15-7.8 mum were prepared and their liquid crystallinity was examined. The nanosheet colloids with different lateral sizes were obtained by exfoliation of single crystals of layered niobate K4Nb6O17 and subsequent ultrasonication. Naked-eye and microscope observations of the nanosheet colloids between crossed polarizers revealed liquid crystallinity of the sols characterized by birefringence as functions of the lateral sizes and concentration of the nanosheets. The nanosheet colloids with smaller lateral sizes (0.15-1.9 mum) varied from isotropic to biphasic (isotropic + liquid crystalline), and finally to fully liquid crystalline states as the colloid concentration increased. The phase transition concentrations (from isotropic to biphasic and biphasic to liquid crystalline) decreased with increasing aspect ratio (lateral-to-thickness ratio) of the nanosheets, almost in accordance with the prediction by Onsager theory, indicating that the liquid crystallinity is explained basically by excluded-volume effect between the nanosheets. On the other hand, the colloids with larger lateral sizes (6.2 and 7.8 mum) stably kept liquid crystalline state even at very low concentration (5.1 x 10-6 in volume fraction), which was much lower than that expected from the theory.

  17. Intractable hyperkalemia due to nicorandil induced potassium channel syndrome

    Directory of Open Access Journals (Sweden)

    Vivek Chowdhry

    2015-01-01

    Full Text Available Nicorandil is a commonly used antianginal agent, which has both nitrate-like and ATP-sensitive potassium (K ATP channel activator properties. Activation of potassium channels by nicorandil causes expulsion of potassium ions into the extracellular space leading to membrane hyperpolarization, closure of voltage-gated calcium channels and finally vasodilatation. However, on the other hand, being an activator of K ATP channel, it can expel K + ions out of the cells and can cause hyperkalemia. Here, we report a case of nicorandil induced hyperkalemia unresponsive to medical treatment in a patient with diabetic nephropathy.

  18. Patterns in potassium dynamics in forest ecosystems.

    Science.gov (United States)

    Tripler, Christopher E; Kaushal, Sujay S; Likens, Gene E; Walter, M Todd

    2006-04-01

    The biotic cycling of potassium (K) in forest systems has been relatively understudied in comparison with nitrogen (N) and phosphorus (P) despite its critical roles in maintaining the nutrition of primary production in forests. We investigated the ecological significance of K in forests from a literature review and data synthesis. We focused on (1) describing patterns of the effects of K availability on aboveground growth and change in foliar tissue of tree species from a variety of forests; and (2) documenting previously unreported relationships between hydrologic losses of K and N in forested watersheds from the Americas. In a review of studies examining tree growth under K manipulations/fertilizations, a high percentage (69% of studies) showed a positive response to increases in K availability in forest soils. In addition, 76% of the tree studies reviewed showed a positive and significant increase in K concentrations in plant tissue after soil K manipulation/fertilization. A meta-analysis on a subset of the reviewed studies was found to provide further evidence that potassium effects tree growth and increased tissue [K] with an effect size of 0.709 for growth and an overall effect size of 0.56. In our review of watershed studies, we observed that concentrations of K typically decreased during growing seasons in streams draining forested areas in the Temperate Zones and were responsive to vegetation disturbance in both temperate and tropical regions. We found a strong relationship (r2 = 0.42-0.99) between concentrations of K and N (another critical plant nutrient) in stream water, suggesting that similar mechanisms of biotic retention may control the flow of these nutrients. Furthermore, K dynamics appear to be unique among the base cations, e.g. calcium, magnesium, and sodium, because the others do not show similar seasonal patterns to K. We suggest that K may be important to the productivity and sustenance of many forests, and its dynamics and ecological

  19. Role of Saccharomyces cerevisiae Trk1 in stabilization of intracellular potassium content upon changes in external potassium levels.

    Science.gov (United States)

    Herrera, Rito; Alvarez, María C; Gelis, Samuel; Kodedová, Marie; Sychrová, Hana; Kschischo, Maik; Ramos, José

    2014-01-01

    Saccharomyces cerevisiae cells are able to grow at very different potassium concentrations adapting its intracellular cation levels to changes in the external milieu. Potassium homeostasis in wild type cells resuspended in media with low potassium is an example of non-perfect adaptation since the same intracellular concentration is not approached irrespective of the extracellular levels of the cation. By using yeasts lacking the Trk1,2 system or expressing different versions of the mutated main plasma membrane potassium transporter (Trk1), we show that Trk1 is not essential for adaptation to potassium changes but the dynamics of potassium loss is very different in the wild type and in trk1,2 mutant or in yeasts expressing Trk1 versions with highly impaired transport characteristics. We also show that the pattern here described can be also fulfilled by heterologous expression of NcHAK1, a potassium transporter not belonging to the TRK family. Hyperpolarization and cationic drugs sensitivity in mutants with defective transport capacity provide additional support to the hypothesis of connections between the activity of the Trk system and the plasma membrane H(+) ATPase (Pma1) in the adaptive process. © 2013.

  20. Biology of the KCNQ1 Potassium Channel

    Directory of Open Access Journals (Sweden)

    Geoffrey W. Abbott

    2014-01-01

    Full Text Available Ion channels are essential for basic cellular function and for processes including sensory perception and intercellular communication in multicellular organisms. Voltage-gated potassium (Kv channels facilitate dynamic cellular repolarization during an action potential, opening in response to membrane depolarization to facilitate K+ efflux. In both excitable and nonexcitable cells other, constitutively active, K+ channels provide a relatively constant repolarizing force to control membrane potential, ion homeostasis, and secretory processes. Of the forty known human Kv channel pore-forming α subunits that coassemble in various combinations to form the fundamental tetrameric channel pore and voltage sensor module, KCNQ1 is unique. KCNQ1 stands alone in having the capacity to form either channels that are voltage-dependent and require membrane depolarization for activation, or constitutively active channels. In mammals, KCNQ1 regulates processes including gastric acid secretion, thyroid hormone biosynthesis, salt and glucose homeostasis, and cell volume and in some species is required for rhythmic beating of the heart. In this review, the author discusses the unique functional properties, regulation, cell biology, diverse physiological roles, and involvement in human disease states of this chameleonic K+ channel.

  1. Incommensurate lattice modulations in Potassium Vanadate

    Science.gov (United States)

    Chakoumakos, Bryan; Banerjee, Arnab; Mark, Lumsden; Cao, Huibo; Kim, Jong-Woo; Hoffman, Christina; Wang, Xiaoping

    Potassium Vanadate (K2V3O8) is an S = 1/2 2D square lattice antiferromagnet that shows spin reorientation indicating a strong coupling between the magnetism and its dielectric properties with a promise of rich physics that promises multiferroicity. These tangible physical properties are strongly tied through a spin-lattice coupling to the underlying lattice and superlattice behavior. It has a superlattice (SL) onsetting below Tc = 115 K with an approximate [3 x 3 x 2] modulation. Here we present our recent experiments at TOPAZ beamline at SNS which for the first time proves conclusively that the lattice modulations are incommensurate, with an in-plane Q of 0.315. We will also show our attempts to refine the data using JANA which requires a redefinition of the lattice, as well as the temperature and Q dependence of the superlattice modulation measured using neutrons at HFIR and synchrotron x-rays at APS. Our results are not only relevant for the ongoing search of multifunctional behavior in K2V3O8 but also generally for the superlattice modulations observed in a large family of fresnoites. Work performed at ORNL and ANL is supported by U.S. Dept. of Energy, Office of Basic Energy Sciences and Office of User Facilities Division.

  2. Sea Anemone Toxins Affecting Potassium Channels

    Science.gov (United States)

    Diochot, Sylvie; Lazdunski, Michel

    The great diversity of K+ channels and their wide distribution in many tissues are associated with important functions in cardiac and neuronal excitability that are now better understood thanks to the discovery of animal toxins. During the past few decades, sea anemones have provided a variety of toxins acting on voltage-sensitive sodium and, more recently, potassium channels. Currently there are three major structural groups of sea anemone K+ channel (SAK) toxins that have been characterized. Radioligand binding and electrophysiological experiments revealed that each group contains peptides displaying selective activities for different subfamilies of K+ channels. Short (35-37 amino acids) peptides in the group I display pore blocking effects on Kv1 channels. Molecular interactions of SAK-I toxins, important for activity and binding on Kv1 channels, implicate a spot of three conserved amino acid residues (Ser, Lys, Tyr) surrounded by other less conserved residues. Long (58-59 amino acids) SAK-II peptides display both enzymatic and K+ channel inhibitory activities. Medium size (42-43 amino acid) SAK-III peptides are gating modifiers which interact either with cardiac HERG or Kv3 channels by altering their voltage-dependent properties. SAK-III toxins bind to the S3C region in the outer vestibule of Kv channels. Sea anemones have proven to be a rich source of pharmacological tools, and some of the SAK toxins are now useful drugs for the diagnosis and treatment of autoimmune diseases.

  3. Implementation and evaluation of a nurse-centered computerized potassium regulation protocol in the intensive care unit - a before and after analysis

    NARCIS (Netherlands)

    Hoekstra, Miriam; Vogelzang, Mathijs; Drost, Jose T.; Janse, Marcel; Loef, Bert G.; van der Horst, Iwan C. C.; Zijlstra, Felix; Nijsten, Maarten W. N.

    2010-01-01

    Background: Potassium disorders can cause major complications and must be avoided in critically ill patients. Regulation of potassium in the intensive care unit (ICU) requires potassium administration with frequent blood potassium measurements and subsequent adjustments of the amount of potassium

  4. Evaluating status change of soil potassium from path model

    National Research Council Canada - National Science Library

    He, Wenming; Chen, Fang

    2013-01-01

    .... In this study, plot experiments were designed into different treatments, and soil samples were collected and further analyzed in laboratory to investigate soil properties influence on soil potassium forms...

  5. Effects of different cavity‑disinfectants and potassium titanyl ...

    African Journals Online (AJOL)

    disinfectants and potassium titanyl phosphate (KTP) laser on microtensile bond strength to primary dentin. Chlorhexidine (CHX), propolis (PRO), ozonated water (OW), gaseous ozone (OG) and KTP laser were used for this purpose. Methodology: ...

  6. Thermal decomposition of potassium bis-oxalatodiaqua-indate (III ...

    Indian Academy of Sciences (India)

    2] 3H2O. Thermal decomposition studies show that the compound decomposes first to the anhydrous potassium indium oxalate ... Bio-inorganic Chemistry Laboratories, School of Chemistry, Andhra University, Visakhapatnam 530 003, India ...

  7. Formulation, Characterization and Physicochemical Evaluation of Potassium Citrate Effervescent Tablets

    National Research Council Canada - National Science Library

    Fatemeh Fattahi; Abolfazl Aslani

    2013-01-01

    Purpose: The aim of this study was to design and formulation of potassium citrate effervescent tablet for reduction of calcium oxalate and urate kidney stones in patients suffering from kidney stones. Methods...

  8. Potassium Ferrate: A Novel Chemical Warfare Agent Decontaminant

    National Research Council Canada - National Science Library

    Greene, Russell; von Fahnestock, F. M; Monzyk, Bruce

    2004-01-01

    ..., and/or unsatisfactory CWA destruction efficiencies. Potassium ferrate (K2FeO4) addresses all of these issues through its high oxidation potential, stable shelf life, and benign reduced state, namely iron oxide...

  9. A Simplified Extemporaneously Prepared Potassium Chloride Oral Solution.

    Science.gov (United States)

    Tannous, Elias; Tal, Yana; Amarny, Kamal

    2016-01-01

    Although commercial preparations of oral potassium supplements are usually available, there are times when our Medical Center is faced with situations in which the oral solution of potassium chloride is not available. This solution is necessary for our pediatric outpatients who cannot swallow tablets and need an oral solution. Moreover, there are no studies available which describe an extemporaneously prepared potassium chloride oral solution on which we can rely for assigning a beyond-use date. The aim of this study was to formulate an extemporaneous pediatric oral solution of potassium chloride and to determine the physical and chemical stability of this preparation. We prepared 1 mMoL/mL by withdrawing 25 mL of potassium chloride 14.9%. Ora-Sweet SF was added to 50 mL in a metered flask. The solution was kept refrigerated (2°C to 8°C). Samples were withdrawn to measure potassium concentration, pH, and microbial overgrowth. The test was performed by our biochemical laboratory. The oral solution of potassium chloride 1 mMoL/mL stored at 2°C to 8°C maintained at least 91% of the initial concentration for 28 days. There were no notable changes in pH, and the solution remained physically stable with no visual microbial growth. The oral solution of potassium chloride 1 mMoL/mL prepared in Ora-Sweet and stored at 2°C to 8°C in amber glass bottles is expected to remain stable for 28 days. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

  10. Formulation, Characterization and Physicochemical Evaluation of Potassium Citrate Effervescent Tablets

    OpenAIRE

    Fatemeh Fattahi; Abolfazl Aslani

    2013-01-01

    Purpose: The aim of this study was to design and formulation of potassium citrate effervescent tablet for reduction of calcium oxalate and urate kidney stones in patients suffering from kidney stones. Methods: In this study, 13 formulations were prepared from potassium citrate and effervescent base in different concentration. The flowability of powders and granules was studied. Then effervescent tablets were prepared by direct compression, fusion and wet granulation methods. The prepared tabl...

  11. Optimizing potassium ferrate for textile wastewater treatment by RSM

    Directory of Open Access Journals (Sweden)

    Maryam Moradnia

    2016-08-01

    Full Text Available Background: Application of potassium ferrate is a chemical oxidation approach used for water and wastewater treatment. The aim of this study is to apply central composite design (CCD and response surface methodology (RSM to optimize potassium ferrate consumption in the treatment of wastewater from carpet industries. Methods: Samples in this experimental study were collected from wastewater, originating from a carpet factory. Wastewater sampling was carried out monthly for a period of two seasons. Ferrate oxidation experiments were conducted by means of a conventional jar-test apparatus. The time and speed for mixing were set with an automatic controller. Parameters of study were measured based on given methodologies in Standard method for examining water and wastewater. CCD and RSM were applied to optimize the operating variables including potassium ferrate dosage and pH. Results: Results showed that potassium ferrate concentration (A, pH (B, their interactions (AB and quadratic effects (A2 and B2 were significant in the removal of COD, turbidity, color and TSS from carpet industries effluents. At an optimum point (COD: 160 mg/L of potassium ferrate and pH 4, turbidity: 165 mg/L of potassium ferrate and pH 4, color and TSS: pH 4.5 and 150 mg/L of potassium ferrate removal efficiencies for COD, turbidity, color and TSS were 86, 86, 87 and 89%, respectively. Conclusion: Potassium ferrate has a significant impact on pollutants decomposition and the removal of color from wastewater produced in carpet industries. This process can be employed for the pretreatment or post treatment of wastewaters containing refractory organic pollutants. CCD and RSM are suitable tools for experimental design.

  12. Optimizing potassium ferrate for textile wastewater treatment by RSM

    OpenAIRE

    Maryam Moradnia; Masoud Panahifard; Kavoos Dindarlo; Hamzeh Ali Jamali

    2016-01-01

    Background: Application of potassium ferrate is a chemical oxidation approach used for water and wastewater treatment. The aim of this study is to apply central composite design (CCD) and response surface methodology (RSM) to optimize potassium ferrate consumption in the treatment of wastewater from carpet industries. Methods: Samples in this experimental study were collected from wastewater, originating from a carpet factory. Wastewater sampling was carried out monthly for a p...

  13. Evaluating status change of soil potassium from path model.

    Directory of Open Access Journals (Sweden)

    Wenming He

    Full Text Available The purpose of this study is to determine critical environmental parameters of soil K availability and to quantify those contributors by using a proposed path model. In this study, plot experiments were designed into different treatments, and soil samples were collected and further analyzed in laboratory to investigate soil properties influence on soil potassium forms (water soluble K, exchangeable K, non-exchangeable K. Furthermore, path analysis based on proposed path model was carried out to evaluate the relationship between potassium forms and soil properties. Research findings were achieved as followings. Firstly, key direct factors were soil S, ratio of sodium-potassium (Na/K, the chemical index of alteration (CIA, Soil Organic Matter in soil solution (SOM, Na and total nitrogen in soil solution (TN, and key indirect factors were Carbonate (CO3, Mg, pH, Na, S, and SOM. Secondly, path model can effectively determine direction and quantities of potassium status changes between Exchangeable potassium (eK, Non-exchangeable potassium (neK and water-soluble potassium (wsK under influences of specific environmental parameters. In reversible equilibrium state of [Formula: see text], K balance state was inclined to be moved into β and χ directions in treatments of potassium shortage. However in reversible equilibrium of [Formula: see text], K balance state was inclined to be moved into θ and λ directions in treatments of water shortage. Results showed that the proposed path model was able to quantitatively disclose moving direction of K status and quantify its equilibrium threshold. It provided a theoretical and practical basis for scientific and effective fertilization in agricultural plants growth.

  14. Changes in plasma potassium concentration during carbon dioxide pneumoperitoneum

    DEFF Research Database (Denmark)

    Perner, A; Bugge, K; Lyng, K M

    1999-01-01

    Hyperkalaemia with ECG changes had been noted during prolonged carbon dioxide pneumoperitoneum in pigs. We have compared plasma potassium concentrations during surgery in 11 patients allocated randomly to undergo either laparoscopic or open appendectomy and in another 17 patients allocated randomly...... to either carbon dioxide pneumoperitoneum or abdominal wall lifting for laparoscopic colectomy. Despite an increasing metabolic acidosis, prolonged carbon dioxide pneumoperitoneum resulted in only a slight increase in plasma potassium concentrations, which was both statistically and clinically insignificant...

  15. Potassium application to table grape clusters after veraison increases soluble solids by enhancing berry water loss

    Science.gov (United States)

    Potassium salt solutions were applied twice to clusters of several table grapes cultivars, after the onset of veraison and three weeks later. Potassium bicarbonate, potassium sorbate, and glycine-complexed potassium, a commercial fertilizer product, increased soluble solids content consistently, whi...

  16. Genetic control of potassium content of common bean seeds

    Directory of Open Access Journals (Sweden)

    Nerison Luís Poersch

    2011-06-01

    Full Text Available The objective of this work was to investigate possible maternal effects on potassium content of common bean seeds, as well as to estimate the heritability and selection gains in early hybrid generations for this character and to evaluate the efficiency of genetic selection to improve the nutritional quality of common bean (Phaseolus vulgaris. Crosses with four cultivars from the Mesoamerican gene pool yielded the reciprocal F1 and F2 generations and the backcrossed populations (BCP1 and BCP2. The potassium content of the progenies was measured via nitric‑perchloric digestion and flame photometry. The potassium content in the tested progenies varied from 6.0 to 14.9 g kg-1 dry matter, and no significant maternal effect was observed. The narrow-sense heritability ranged from low (33.26% to intermediate (43.05%. Partial dominance was observed for low potassium content in the seeds. No increase in potassium content was obtained through selection. Breeding common bean plants for increasing potassium content in seeds may be difficult because the local environment strongly influences the character.

  17. Potassium-doped n-type bilayer graphene

    Science.gov (United States)

    Yamada, Takatoshi; Okigawa, Yuki; Hasegawa, Masataka

    2018-01-01

    Potassium-doped n-type bilayer graphene was obtained. Chemical vapor deposited bilayer and single layer graphene on copper (Cu) foils were used. After etching of Cu foils, graphene was dipped in potassium hydroxide aqueous solutions to dope potassium. Graphene on silicon oxide was characterized by X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), and Raman spectroscopy. Both XPS and EDX spectra indicated potassium incorporation into the bilayer graphene via intercalation between the graphene sheets. The downward shift of the 2D peak position of bilayer graphene after the potassium hydroxide (KOH) treatment was confirmed in Raman spectra, indicating that the KOH-treated bilayer graphene was doped with electrons. Electrical properties were measured using Hall bar structures. The Dirac points of bilayer graphene were shifted from positive to negative by the KOH treatment, indicating that the KOH-treated bilayer graphene was n-type conduction. For single layer graphene after the KOH treatment, although electron doping was confirmed from Raman spectra, the peak of potassium in the X-ray photoelectron spectroscopy (XPS) spectrum was not detected. The Dirac points of single layer graphene with and without the KOH treatment showed positive.

  18. The relationship between serum potassium, potassium variability and in-hospital mortality in critically ill patients and a before-after analysis on the impact of computer-assisted potassium control

    NARCIS (Netherlands)

    Hessels, Lara; Hoekstra, Miriam; Mijzen, Lisa J.; Vogelzang, Mathijs; Dieperink, Wim; Oude Lansink, Annemieke; Nijsten, Maarten W.

    2015-01-01

    Introduction: The relationship between potassium regulation and outcome is not known. Our first aim in the present study was to determine the relationship between potassium level and variability in (ICU) stay and outcome. The second aim was to evaluate the impact of a computer-assisted potassium

  19. Crystal Structure of the Sodium-Potassium Pump (Na⁺, K⁺-ATPase) with Bound Potassium and Ouabain

    National Research Council Canada - National Science Library

    Haruo Ogawa; Takehiro Shinoda; Flemming Cornelius; Chikashi Toyoshima

    2009-01-01

    The sodium-potassium pump (Na⁺,K⁺-ATPase) is responsible for establishing Na⁺ and K⁺ concentration gradients across the plasma membrane and therefore plays an essential role in, for instance, generating action potentials...

  20. Tomato yield and potassium concentrations in soil and in plant petioles as affected by potassium fertirrigation

    Directory of Open Access Journals (Sweden)

    FONTES PAULO CEZAR REZENDE

    2000-01-01

    Full Text Available Tomato (Lycopersicon esculentum Mill. cv. Santa Clara was grown on a silt clay soil with 46 mg dm-3 Mehlich 1 extractable K, to evaluate the effects of trickle-applied K rates on fruit yield and to establish K critical concentrations in soil and in plant petioles. Six potassium rates (0, 48, 119, 189, 259 and 400 kg ha-1 K were applied in a randomized complete block design with four replications. Soil and plant K critical levels were determined at two plant growth stages (at the beginning of the second and fourth cluster flowering. Total, marketable and weighted yields increased with K rates, reaching their maximum of 86.4, 73.4, and 54.9 ton ha-1 at 198, 194, and 125 kg ha-1 K , respectively. At the first soil sampling date K critical concentrations in the soil associated with K rates for maximum marketable and weighted yields were 92 and 68 mg dm-3, respectively. Potassium critical concentrations in the dry matter of the petioles sampled by the beginning of the second and fourth cluster flowering time, associated with maximum weighted yield, were 10.30 and 7.30 dag kg-1, respectively.

  1. Potassium channel family in giant motor axons of Aglantha digitale.

    Science.gov (United States)

    Meech, R W; Mackie, G O

    1993-03-01

    1. The simplicity of the jellyfish nervous system makes it an ideal preparation to assess the contributions of different ion channels to behavior. In the giant motor axons of the jellyfish Aglantha digitale, low-threshold spikes elicit slow swimming, whereas escape swimming depends on a higher-threshold, overshooting sodium-dependent action potential. At least three kinetically distinct transient potassium channels (fast, intermediate, and slow) are concerned with spike management in this preparation. 2. In situ recording with patch-clamp micropipettes from clusters of potassium channels provides a means of studying their properties in isolation. The three classes of ion channel were identified in ensemble current averages by their kinetics, their response to a conditioning prepulse and their voltage dependence. All three were highly selective for potassium, and the reversal potential of their unitary currents depended on the level of potassium used to fill the patch pipette. 3. A single potassium permeability coefficient (PK) calculated from the Goldman, Hodgkin, Katz "constant field" equation was used to fit unitary current data from all three channels in concentrations of external potassium < or = 500 mM. 4. Data from ensemble tail currents in seawater indicated that the sodium permeability coefficient (PNa) of channels with either intermediate or slow kinetics was < or = 0.015 PK; preliminary data from channels with fast kinetics suggested that they too had a PNa/PK selectivity of approximately 0.01. 5. We propose that spike management in the giant motor axons of Aglantha depends on three members of a family of potassium-selective ion channels that seem likely to be structurally related.

  2. Combustion aerosols from potassium-containing fuels

    Energy Technology Data Exchange (ETDEWEB)

    Balzer Nielsen, Lars

    1998-12-31

    The scope of the work presented in this thesis is the formation and evolution of aerosol particles in the submicron range during combustion processes, in particular where biomass is used alone or co-fired with coal. An introduction to the formation processes of fly ash in general and submicron aerosol in particular during combustion is presented, along with some known problems related to combustion of biomass for power generation. The work falls in two parts. The first is the design of a laboratory setup for investigation of homogeneous nucleation and particle dynamics at high temperature. The central unit of the setup is a laminar flow aerosol condenser (LFAC), which essentially is a 173 cm long tubular furnace with an externally cooled wall. A mathematical model is presented which describes the formation and evolution of the aerosol in the LFAC, where the rate of formation of new nuclei is calculated using the so-called classical theory. The model includes mass and energy conservation equations and an expression for the description of particle growth by diffusion. The resulting set of nonlinear second-order partial differential equations are solved numerically using the method of orthogonal collocation. The model is implemented in the FORTRAN code MONAERO. The second part of this thesis describes a comprehensive investigation of submicron aerosol formation during co-firing of coal and straw carried out at a 380 MW{sub Th} pulverized coal unit at Studstrup Power Plant, Aarhus. Three types of coal are used, and total boiler load and straw input is varied systematically. Straw contains large amounts of potassium, which is released during combustion. Submicron aerosol is sampled between the two banks of the economizer at a flue gas temperature of 350 deg. C using a novel ejector probe. The aerosol is characterized using the SMPS system and a Berner-type low pressure impactor. The chemical composition of the particles collected in the impactor is determined using

  3. Tetradecacobalt(II)-containing 36-niobate [Co14(OH)16(H2O)8Nb36O106]20- and its photocatalytic H2 evolution activity.

    Science.gov (United States)

    Niu, Jingyang; Li, Fang; Zhao, Junwei; Ma, Pengtao; Zhang, Dongdi; Bassil, Bassem; Kortz, Ulrich; Wang, Jingping

    2014-08-04

    A gigantic Co14-containing 36-niobate, Na12K8[Co14(OH)16(H2O)8Nb36O106]⋅71H2O (1), has been prepared by the hydrothermal method and structurally characterized. Polyanion [Co14(OH)16(H2O)8Nb36O106](20-) (1 a) comprises a central Co7 core, surrounded by another seven isolated Co(2+) ions and six Lindqvist-type (Nb6O19) hexaniobate fragments. This is the first example of a high-nuclear cobalt-cluster-containing polyoxoniobate. The photocatalytic H2 evolution activity of Pt-loaded 1 was observed in methanol solution under irradiation using a 300 W Xe lamp. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Optical isolator based on the electro-optic effect in periodically poled lithium niobate with the addition of a half domain.

    Science.gov (United States)

    Shi, Lei; Tian, Linghao; Chen, Xianfeng

    2012-12-20

    We propose an optical isolator based on the electro-optic (EO) effect of periodically poled lithium niobate (PPLN). When the EO effect occurs in PPLN under a TE field, each domain serves as a half-wave plate under the quasi-phase-matching condition, and PPLN shows optical activity similar to quartz. The introduction of an additional half-domain to the normal PPLN changes the incident azimuth angle of the reflected light. As a result, the reflected light does not return to the original polarization state. Thus, the optical rotation accumulates and optical isolation occurs. The isolator can be employed for all linearly polarized light and has the advantage of being used in a weak-light system with low driving voltage and high isolation contrast.

  5. Generation of 43 W of quasi-continuous 780 nm laser light via high-efficiency, single-pass frequency doubling in periodically poled lithium niobate crystals.

    Science.gov (United States)

    Chiow, Sheng-wey; Kovachy, Tim; Hogan, Jason M; Kasevich, Mark A

    2012-09-15

    We demonstrate high-efficiency frequency doubling of the combined output of two 1560 nm 30 W fiber amplifiers via single pass through periodically poled lithium niobate (PPLN) crystals. The temporal profile of the 780 nm output is controlled by adjusting the relative phase between the seeds of the amplifiers. We obtain a peak power of 34 W of 780 nm light by passing the combined output through one PPLN crystal, and a peak power of 43 W by passing through two cascading PPLN crystals. This source provides high optical power, excellent beam quality and spectral purity, and agile frequency and amplitude control in a simple and compact setup, which is ideal for applications such as atom optics using Rb atoms.

  6. Nonlinear excitations and charge transport in lithium niobate crystals investigated using femtosecond-light gratings; Nichtlineare Anregungen und Ladungstransport in Lithiumniobatkristallen untersucht mit Femtosekunden-Lichtgittern

    Energy Technology Data Exchange (ETDEWEB)

    Maxein, Karl Dominik

    2009-12-15

    Lithium niobate (LiNbO{sub 3}) is a widely employed material in nonlinear optics and photonics. Its usage is hampered by the photorefractive effect, which can destroy beam profiles and phase matching conditions. Existing methods to suppress photorefraction fail for the interesting regime of very high intensities and short pulses. Therefore, the photorefractive effect is investigated using femtosecond laser pulses: By utilizing so-called 2K holography, the occupation of energetically shallow traps is observed to occur in less than 100 fs after a two-photon excitation. Writing of photorefractive gratings into oxidized iron-doped LiNbO{sub 3} is much faster with pulses than with cw light. This is explained by the sensitization of the crystal due to charge trapping in photorefractive centers after nonlinear excitations. Finally, light-induced scattering of pulse light is suppressed compared to the scattering of cw light due to the small coherence length of pulses. (orig.)

  7. Synthesis and photocatalytic activity of rhodium-doped calcium niobate nanosheets for hydrogen production from a water/methanol system without cocatalyst loading.

    Science.gov (United States)

    Okamoto, Yohei; Ida, Shintaro; Hyodo, Junji; Hagiwara, Hidehisa; Ishihara, Tatsumi

    2011-11-16

    Rhodium-doped calcium niobate nanosheets were synthesized by exfoliating layered KCa(2)Nb(3-x)Rh(x)O(10-δ) and exhibited high photocatalytic activity for H(2) production from a water/methanol system without cocatalyst loading. The maximum H(2) production rate of the nanosheets was 165 times larger than that of the parent Rh-doped layered oxide. The quantum efficiency at 300 nm was 65%. In this system, the methanol was oxidized to formaldehyde (main product), formic acid, and carbon dioxide by holes, whereas electrons cause the reduction of water to H(2). The conductivity of the parent layered oxide was decreased by doping, which indicates the octahedral RhO(6) unit in the lattice of the nanosheet functions as an electron trap site. The RhO(6) units in the nanosheet probably also act as reaction sites for H(2) evolution.

  8. Urinary potassium to urinary potassium plus sodium ratio can accurately identify hypovolemia in nephrotic syndrome: a provisional study.

    Science.gov (United States)

    Keenswijk, Werner; Ilias, Mohamad Ikram; Raes, Ann; Donckerwolcke, Raymond; Walle, Johan Vande

    2018-01-01

    There is evidence pointing to a decrease of the glomerular filtration rate (GFR) in a subgroup of nephrotic children, likely secondary to hypovolemia. The aim of this study is to validate the use of urinary potassium to the sum of potassium plus sodium ratio (UK/UK+UNa) as an indicator of hypovolemia in nephrotic syndrome, enabling detection of those patients who will benefit from albumin infusion. We prospectively studied 44 nephrotic children and compared different parameters to a control group (36 children). Renal perfusion and glomerular permeability were assessed by measuring clearance of para-aminohippurate and inulin. Vaso-active hormones and urinary sodium and potassium were also measured. Subjects were grouped into low, normal, and high GFR groups. In the low GFR group, significantly lower renal plasma flow (p = 0.01), filtration fraction (p = 0.01), and higher UK/UK+UNa (p = 0.03) ratio were noted. In addition, non-significant higher plasma renin activity (p = 0.11) and aldosteron (p = 0.09) were also seen in the low GFR group. A subgroup of patients in nephrotic syndrome has a decrease in glomerular filtration, apparently related to hypovolemia which likely can be detected by a urinary potassium to potassium plus sodium ratio > 0.5-0.6 suggesting benefit of albumin infusion in this subgroup. What is Known: • Volume status can be difficult to assess based on clinical parameters in nephrotic syndrome, and albumin infusion can be associated with development of pulmonary edema and fluid overload in these patients. What is New: • Urinary potassium to the sum of urinary potassium plus sodium ratio can accurately detect hypovolemia in nephrotic syndrome and thus identify those children who would probably respond to albumin infusion.

  9. Soil salinity and yield of mango fertigated with potassium sources

    Directory of Open Access Journals (Sweden)

    Marcio A. Carneiro

    Full Text Available ABSTRACT Irrigated fruit crops have an important role in the economic and social aspects in the region of the Sub-middle São Francisco River Valley. Thus, the aim of this study was to evaluate soil salinity and the productive aspects of the mango crop, cv. Tommy Atkins, fertigated with doses of potassium chloride (KCl and potassium sulfate (K2SO4 during two crop cycles (from January to March 2014 and from January to March 2015. The experiment was carried out in a strip-split-plot design and five potassium doses (50, 75, 100, 125 and 150% of the recommended dose as plots and two potassium sources (KCl and K2SO4 as subplots, with four replicates. Soil electrical conductivity (EC, exchangeable sodium (Na+ and potassium (K+ contents and pH were evaluated. In addition, the number of commercial fruits and yield were determined. The fertilization with KCl resulted in higher soil EC compared with K2SO4 fertigation. Soil Na+ and K+ contents increased with increasing doses of fertilizers. K2SO4 was more efficient for the production per plant and yield than KCl. Thus, under the conditions of this study, the K2SO4 dose of 174.24 g plant-1 (24.89 kg ha-1 or 96.8% of recommendation, spacing of 10 x 7 m was recommended for a yield of 23.1 t ha-1 of mango fruits, cv. Tommy Atkins.

  10. Preparation of Potassium Ferrate from Spent Steel Pickling Liquid

    Directory of Open Access Journals (Sweden)

    Yu-Ling Wei

    2015-09-01

    Full Text Available Potassium ferrate (K2FeO4 is a multi-functional green reagent for water treatment with considerable combined effectiveness in oxidization, disinfection, coagulation, sterilization, adsorption, and deodorization, producing environment friendly Fe(III end-products during the reactions. This study uses a simple method to lower Fe(VI preparation cost by recycling iron from a spent steel pickling liquid as an iron source for preparing potassium ferrate with a wet oxidation method. The recycled iron is in powder form of ferrous (93% and ferric chlorides (7%, as determined by X-ray Absorption Near Edge Spectrum (XANES simulation. The synthesis method involves three steps, namely, oxidation of ferrous/ferric ions to form ferrate with NaOCl under alkaline conditions, substitution of sodium with potassium to form potassium ferrate, and continuously washing impurities with various organic solvents off the in-house ferrate. Characterization of the in-house product with various instruments, such as scanning electron microscopy (SEM, ultraviolet-visible (UV-Vis, X-ray diffraction (XRD, and X-ray absorption spectroscopy (XAS, proves that product quality and purity are comparative to a commercialized one. Methylene blue (MB de-colorization tests with in-house potassium ferrate shows that, within 30 min, almost all MB molecules are de-colorized at a Fe/carbon mole ratio of 2/1.

  11. Determinants of renal potassium excretion in critically ill patients: the role of insulin therapy.

    Science.gov (United States)

    Hoekstra, Miriam; Yeh, Lu; Lansink, Annemieke Oude; Vogelzang, Mathijs; Stegeman, Coen A; Rodgers, Michael G G; van der Horst, Iwan C C; Wietasch, Götz; Zijlstra, Felix; Nijsten, Maarten W N

    2012-03-01

    Insulin administration lowers plasma potassium concentration by augmenting intracellular uptake of potassium. The effect of insulin administration on renal potassium excretion is unclear. Some studies suggest that insulin has an antikaliuretic effect although plasma potassium levels were poorly controlled. Since the introduction of glycemic control in the intensive care unit, insulin use has increased. We examined the relation between administered insulin and renal potassium excretion in critically ill patients under computer-assisted glucose and potassium regulation. Prospective observational study. Twelve-bed surgical intensive care unit of a university teaching hospital. Consecutive intensive care unit patients. Potassium and glucose levels were regulated by a computer-assisted decision support system. Both potassium and insulin were continuously administered by syringe pump. Renal potassium excretion was measured daily in the 24-hr urine collections. The 24-hr urinary samples of patients with kidney failure or on renal replacement therapy were excluded. Multivariate analysis with potassium excretion as the dependent variable was performed. In 178 consecutive patients, 1,456 24-hr urinary samples, were analyzed. Mean ± SD plasma potassium was 4.2 ± 0.3 mmol/L, with 79 ± 46 mmol/d of potassium administered and a mean insulin dose of 53 ± 38 U/day. Renal potassium excretion was 126 ± 51 mmol/day. After multivariate analysis correcting for relevant variables (including diuretics, pH, potassium levels and renal sodium excretion), insulin administration was independently and positively associated with renal potassium excretion. Other significant variables were potassium levels, potassium administration, renal sodium and chloride excretion, creatinine clearance, diuretic therapy, pH, known diabetes and intensive care unit admission day (R = .52; p <. 001). Insulin administration is associated with an increase in the renal potassium excretion in critically ill

  12. Potassium [(1S-1-azido-2-phenylethyl]trifluoridoborate

    Directory of Open Access Journals (Sweden)

    Tore Lejon

    2012-08-01

    Full Text Available The title compound, K+·C8H8BF3N3−, is a salt containing the chiral organic trifluoridoborate anion. The organic anions and potassium cations are tightly bound to each other by the coordination K—F [2.654 (3–3.102 (3 Å] and K—N [2.951 (4–3.338 (4 Å] interactions. Thus, the potassium cation adopts a nine-vertex coordination polyhedron, which can be described as a distorted monocapped tetragonal antiprism. In the crystal, the organic anions and potassium cations form layers parallel to (001. Weak C—H...π interactions between neighbouring phenyl rings further stabilize the crystal.

  13. Influence of potassium loading at different reaction temperatures on the NOx reduction process by potassium-containing coal pellets

    Energy Technology Data Exchange (ETDEWEB)

    Agustin Bueno-Lopez; Avelina Garcia-Garcia; Jose Antonio Caballero; A. Linares-Solano [Universidad de Alicante, Alicante (Spain). Departamento de Quimica Inorganica

    2003-02-01

    The activity of potassium-containing coal pellets and the corresponding free-metal char for NOx reduction in an oxygen-rich environment has been investigated by temperature-programmed reactions (TPRs) up to 750{sup o}C, 2 h isothermal reactions in the range of 250 475{sup o}C and lifetime tests, (until the samples were completely consumed), for selected samples and temperatures. An interesting 'reactivity window', where NOx reduction is observed, but carbon conversion is negligible, was found from TPRs experiment for a high potassium content sample, at moderate temperatures. This interval was not observed for the char. The catalytic effect of potassium is more dramatic at high temperatures, therefore, metal loading and reaction temperature are very much interrelated. Lifetime tests provide a very valuable information (average selectivity, profitable use of samples for NOx reduction, etc.), allowing us to check the whole efficiency of the samples. The progressive addition of potassium to the pellets makes samples more effective in terms of: (i) capacity to reduce higher NOx amounts; (ii) maximum NOx conversion values and (iii) higher values of average selectivity. In general, the samples studied, exhibit a maximum temperature, very much dependent on their potassium contents, that must not be exceeded with a view to practical applications. 24 refs., 6 figs., 2 tabs.

  14. Test Requirements and Conceptual Design for a Potassium Test Loop to Support an Advanced Potassium Rankine Cycle Power Conversion Systems

    Energy Technology Data Exchange (ETDEWEB)

    Yoder, JR.G.L.

    2006-03-08

    Parameters for continuing the design and specification of an experimental potassium test loop are identified in this report. Design and construction of a potassium test loop is part of the Phase II effort of the project ''Technology Development Program for an Advanced Potassium Rankine Power Conversion System''. This program is supported by the National Aeronautics and Space Administration. Design features for the potassium test loop and its instrumentation system, specific test articles, and engineered barriers for ensuring worker safety and protection of the environment are described along with safety and environmental protection requirements to be used during the design process. Information presented in the first portion of this report formed the basis to initiate the design phase of the program; however, the report is a living document that can be changed as necessary during the design process, reflecting modifications as additional design details are developed. Some portions of the report have parameters identified as ''to be determined'' (TBD), reflecting the early stage of the overall process. In cases where specific design values are presently unknown, the report attempts to document the quantities that remain to be defined in order to complete the design of the potassium test loop and supporting equipment.

  15. The relationship between serum potassium, potassium variability and in-hospital mortality in critically ill patients and a before-after analysis on the impact of computer-assisted potassium control.

    Science.gov (United States)

    Hessels, Lara; Hoekstra, Miriam; Mijzen, Lisa J; Vogelzang, Mathijs; Dieperink, Wim; Lansink, Annemieke Oude; Nijsten, Maarten W

    2015-01-06

    The relationship between potassium regulation and outcome is not known. Our first aim in the present study was to determine the relationship between potassium level and variability in (ICU) stay and outcome. The second aim was to evaluate the impact of a computer-assisted potassium regulation protocol. We performed a retrospective before-after study including all patients >15 years of age admitted for more than 24 hours to the ICU of our university teaching hospital between 2002 and 2011. Potassium control was fully integrated with computerized glucose control (glucose and potassium regulation program for intensive care patients (GRIP-II)). The potassium metrics that we determined included mean potassium, potassium variability (defined as the standard deviation of all potassium levels) and percentage of ICU time below and above the reference range (3.5 through 5.0 mmol/L). These metrics were determined for the first ICU day (early phase) and the subsequent ICU days (late phase; that is, day 2 to day 7). We also compared potassium metrics and in-hospital mortality before and after GRIP-II was implemented in 2006. Of all 22,347 ICU admissions, 10,451 (47%) patients were included. A total of 206,987 potassium measurements were performed in these patients. Glucose was regulated by GRIP-II in 4,664 (45%) patients. The overall in-hospital mortality was 22%. There was a U-shaped relationship between the potassium level and in-hospital mortality (P <0.001). Moreover, potassium variability was independently associated with outcome. After implementation of GRIP-II, in the late phase the time below 3.5 mmol/L decreased from 9.2% to 3.9% and the time above 5.0 mmol/L decreased from 6.1% to 5.2%, and potassium variability decreased from 0.31 to 0.26 mmol/L (all P <0.001). The overall decrease in in-hospital mortality from 23.3% before introduction of GRIP-II to 19.9% afterward (P <0.001) was not related to a specific potassium subgroup. Hypokalemia, hyperkalemia and

  16. Sodium and potassium lidar system and preliminary result in Brazil

    Science.gov (United States)

    Du, Lifang

    2017-04-01

    This paper reported that the first sodium and potassium lidar was built at November, 2016 in INPE(S23°,W45°) by National Space Science Center, Chinese Academy of Sciences. This system first time realized the potassium and sodium metal layer at the same time above the detection In South America. The lidar system use a powerful pulse YAG laser to pumped two dye lasers at the same time, and join the advanced technology, such as narrow line-width grating technique, efficient laser frequency doubling technique, wavelength automatic locking technique and the double optical fiber in the focal plane for spectra separation technique and so on, which made the 589 nm and 770 nm laser line width to achieve 0.03cm-1 and the laser frequency doubling efficiency to reached above 65%. In this way, the simultaneously detecting the atmosphere at the altitude of 80 110 km by sodium and potassium fluorescence in one lidar facility has been realized. On November 20, 2016, this system began to observation for the first time in Brazil, and it has the detection data of South America about potassium and sodium at the same time. Observed data show that sodium echo photon counting rate is higher than 31874count/160s/96m, potassium echo photon counting rate is higher than 2153count/320s/96m. Comparing with both of at home or abroad, the results are a very good. In particular, the detection results level of potassium take the leading position in the international.

  17. Preparation and Aromatic Hydrocarbon Removal Performance of Potassium Ferrate

    Directory of Open Access Journals (Sweden)

    Wei Guan

    2014-01-01

    Full Text Available This experiment adopts the hypochlorite oxidation method to constantly synthesize potassium ferrate. Under the condition of micropolluted source water pH and on the basis of naphthalene, phenanthrene, and pyrene as research objects, the effects of different systems to remove aromatic hydrocarbons were studied. Various oxidation systems to remove phenanthrene intermediate are analyzed and the detailed mechanisms for removal of phenanthrene are discussed. The study found that the main intermediate of potassium ferrate system to transform phenanthrene is 9,10-phenanthraquinone and its area percentage reached 82.66%; that is, 9,10-phenanthraquinone is the key entity to remove phenanthrene.

  18. [Quantitative determination of penicillins by iodometry using potassium hydrogen peroxymonosulfate].

    Science.gov (United States)

    Blazhevskiĭ, N E; Karpova, S P; Kabachyĭ, V I

    2013-01-01

    The kinetics and stoichiometry of S-oxidation of semisynthetic penicillins (amoxicillin trihydrate, ampicillin trihydrate, sodium salt of oxacillin and ticarcillin disodium salt) by potassium hydrogen peroxymonosulfate in aqueous solutions at pH 3-6 was studied by iodometric titration: 1 mol of KNSO5 per 1 mol of penicillin, the quantitative interaction is achieved in 1 min (time of observation). A unified method was developed and the possibility of quantification of penicillins by the iodometric method using potassium hydrogen peroxymonosulfate as an analytical reagent was shown.

  19. Effet Du Potassium Et Du Deficit Hydrique Modere Sur La ...

    African Journals Online (AJOL)

    Le comportement de 6 génotypes de cette plante, sous deux régimes hydriques, avec ou sans apport de potassium, a été suivi dans des tubes en PVC. Le potassium a été apporté sous forme de KCl ou de K2SO4. Il n\\'y a pas de différence entre les effets du KCl et du K2SO4 sur la transpiration par mg de feuilles sèches ...

  20. Superconductivity in potassium-doped few-layer graphene.

    Science.gov (United States)

    Xue, Mianqi; Chen, Genfu; Yang, Huaixin; Zhu, Yuanhua; Wang, Duming; He, Junbao; Cao, Tingbing

    2012-04-18

    Here we report the successful synthesis of superconducting potassium-doped few-layer graphene (K-doped FLG) with a transition temperature of 4.5 K, which is 1 order of magnitude higher than that observed in the bulk potassium graphite intercalation compound (GIC) KC(8) (T(c) = 0.39 K). The realization of superconductivity in K-doped FLG shows the potential for the development of new superconducting electronic devices using two-dimensional (2D) graphene as a basis material. © 2012 American Chemical Society

  1. Potassium Permanganate as an Alternative for Gold Mining Wastewater Treatment

    Science.gov (United States)

    Ordiales, M.; Fernández, D.; Verdeja, L. F.; Sancho, J.

    2015-09-01

    The feasibility of using potassium permanganate as a reagent for cyanide oxidation in wastewater was experimentally studied. Both artificial and production wastewater from two different gold mines were tested. The experiments had three goals: determine the optimum reagent concentration and reaction time required to achieve total cyanide removal, obtain knowledge of the reaction kinetics, and improve the management of the amount of reagent. The results indicate that potassium permanganate is an effective and reliable oxidizing agent for the removal of cyanide from gold mining wastewater.

  2. Noise controlled synchronization in potassium coupled neural models

    DEFF Research Database (Denmark)

    Postnov, Dmitry E; Ryazanova, Ludmila S; Zhirin, Roman A

    2007-01-01

    The paper applies biologically plausible models to investigate how noise input to small ensembles of neurons, coupled via the extracellular potassium concentration, can influence their firing patterns. Using the noise intensity and the volume of the extracellular space as control parameters, we...... show that potassium induced depolarization underlies the formation of noise-induced patterns such as delayed firing and synchronization. These phenomena are associated with the appearance of new time scales in the distribution of interspike intervals that may be significant for the spatio...

  3. Changes in plasma potassium concentration during carbon dioxide pneumoperitoneum

    DEFF Research Database (Denmark)

    Perner, A; Bugge, K; Lyng, K M

    1999-01-01

    Hyperkalaemia with ECG changes had been noted during prolonged carbon dioxide pneumoperitoneum in pigs. We have compared plasma potassium concentrations during surgery in 11 patients allocated randomly to undergo either laparoscopic or open appendectomy and in another 17 patients allocated randomly...... to either carbon dioxide pneumoperitoneum or abdominal wall lifting for laparoscopic colectomy. Despite an increasing metabolic acidosis, prolonged carbon dioxide pneumoperitoneum resulted in only a slight increase in plasma potassium concentrations, which was both statistically and clinically insignificant....... Thus hyperkalaemia is unlikely to develop in patients with normal renal function undergoing carbon dioxide pneumoperitoneum for laparoscopic surgery....

  4. Potassium changes in trained subjects after potassium loading and during restriction of muscular activity and chronic hyperhydration.

    Science.gov (United States)

    Zorbas, Y G; Federenko, Y F; Naexu, K A

    1996-01-01

    The objective of this investigation was to determine whether urinary and plasma potassium changes developed during prolonged hypokinesia (HK) (decreased number of km/d) in endurance-trained subjects could be minimized or reversed with a daily intake of fluid and salt supplementation (FSS). The studies were performed on 30 endurance-trained male volunteers aged 23-26 yr with an average peak oxygen uptake of 65 mL/kg min during 364 d of HK. All volunteers were on an average of 13.8 km/d prior to their exposure to HK. All volunteers were randomly divided into three groups: 10 volunteers were placed continuously under an average of 14.0 km/d (control subjects), 10 volunteers were subjected continuously to an average of 2.7 km/d (unsupplemented hypokinetic subjects), and 10 volunteers were submitted continuously to an average of 2.7 km/d, and consumed daily an additional amount of 0.1 g sodium chloride (NaCl)/kg body wt and 30 mL water/kg body wt (supplemented hypokinetic subjects). During the prehypokinetic period of 60 d and during the hypokinetic period of 364 d, potassium loading tests were performed with 1.5-1.7 mEq potassium chloride/kg body wt, and potassium, sodium, and chloride excretion in urine and potassium, sodium, and chloride in plasma were determined. In the unsupplemented hypokinetic volunteers, urinary excretion of electrolytes and concentrations of electrolytes in plasma increased significantly as compared to the control and supplemented hypokinetic groups of volunteers. It was concluded that daily intake of fluid and salt supplementation had a favorable effect on regulation of urinary and plasma potassium changes in trained subjects during prolonged HK.

  5. Urinary potassium excretion, renal ammoniagenesis, and risk of graft failure and mortality in renal transplant recipients

    NARCIS (Netherlands)

    Eisenga, Michele F.; Kieneker, Lyanne M.; Soedamah-Muthu, Sabita S.; van den Berg, Else; Deetman, Petronella E.; Navis, Gerjan J.; Gans, Reinold O. B.; Gaillard, Carlo A. J. M.|info:eu-repo/dai/nl/073810339; Bakker, Stephan J. L.; Joosten, Michel M.

    2016-01-01

    Background: Renal transplant recipients (RTRs) have commonly been urged to limit their potassium intake during renal insufficiency and may adhere to this principle after transplantation. Importantly, in experimental animal models, low dietary potassium intake induces kidney injury through

  6. Palytoxin and the sodium/potassium pump--phosphorylation and potassium interaction.

    Science.gov (United States)

    Rodrigues, Antônio M; Infantosi, Antonio F C; de Almeida, Antônio-Carlos G

    2009-05-21

    We proposed a reaction model for investigating interactions between K+ and the palytoxin-sodium-potassium (PTX-Na+/K+) pump complex under conditions where enzyme phosphorylation may occur. The model is composed of (i) the Albers-Post model for Na+/K+-ATPase, describing Na+ and K+ pumping; (ii) the reaction model proposed for Na+/K+-ATPase interactions with its ligands (Na+, K+, ATP, ADP and P) and with PTX. A mathematical model derived for representing the reactions was used to simulate experimental studies of the PTX-induced current, in different concentrations for the pump ligands. The simulations allow interpretation of the simultaneous action of Na+/K+-ATPase phosphorylation and K+ on the PTX-induced channels. The results suggest that(i) phosphorylation increases the PTX toxic effect, increasing its affinity and reducing the K+occlusion rate, and (ii) K+ causes channel blockage, increases the toxin dissociation rate and impedes the induced channel phosphorylation, implying reduction of the PTX toxic effect.

  7. Potassium evaluation in blood of Brazilian athletes using NAA

    Energy Technology Data Exchange (ETDEWEB)

    Kovacs, L.; Zamboni, C.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Nunes, L.A.S.; Lourenco, T.F.; Macedo, D. Vaz de [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

    2010-07-01

    Full text: According to nutrition sources an athlete needs per day at least one gram of potassium for keeping the correct mineral balance in the organism. Its deficiency or even instantaneous low concentration in blood can diminish the athlete performance originating nervous irritability, muscular weakness, and mental disorientation and in more several causes cardiac arrhythmias. In this study the K levels in blood were determined in athletes submitted to constant load exercise at treadmill at LABEX (Laboratorio de Bioquimica do Exercicio - UNICAMP, Brazil) using Neutron Activation Analyses (NAA). The blood samples were collected from male athletes, age 18 to 26 years, before and after the physical training. Immediately after the collection an amount of 10 micro liters of whole blood was transferred to the filter paper and dried for a few minutes using an infrared lamp. To determine the concentration of potassium each sample was irradiated in the nuclear reactor (IEA-R1, 2-4MW, pool type) at IPEN and was gamma counted using an HPGe Spectrometer of High Energy Resolution. The concentrations of the selected element, 1525keV related to the potassium activated {sup 42}K, were calculated using in -house software. The potassium levels were evaluated before and after the physical exercise and the data were compared with the normal range. (author)

  8. Extractahility of Potassium from Some Organic Manures in Aqueous ...

    African Journals Online (AJOL)

    Fig l: (imitative Pl\\1mctittn of Native it” from Marlin: Sanples. The usually high solubility and mobility of potassium in aqueous solution is a useful property in its release phenomenon with respect to fertilizer application in crop production, but which could also be a disadvantage since its effect may be short-lived. l'lowever, it is ...

  9. Effect of potassium simplex optimization medium (KSOM) and ...

    African Journals Online (AJOL)

    In this study, we produced cloned transgenic dairy goat based on dairy goat ear skin fibroblast as donor cells for nuclear transfer (NT), which were modified by human lactoferrin (hLF) gene. The developmental competence of NT embryos was compared with either between different embryo culture medium, potassium ...

  10. Formulation and evaluation of sublingual tablets of losartan potassium

    Directory of Open Access Journals (Sweden)

    Nikunj J. Aghera

    2012-05-01

    Full Text Available Objective: Sublingual tablets of Losartan Potassium were prepared to improve its bioavailability, to avoid pre-systemic metabolism in the gastrointestinal tract and hepatic first pass elimination. Methods: The Sublingual tablets were prepared by direct compression procedure using different concentration of Starch 1500 and microcrystalline cellulose. Compatibility studies of drug and polymer were performed by FTIR spectroscopy and DSC. Preformulation property of API was evaluated. Postcompressional parameters such disintegration time, wetting time, water absorption ratio, in vitro drug release and in vivo bioavailability study of optimized formulation were determined. Results: FTIR spectroscopy and DSC study revealed that there was no possible interaction between drug and polymers. The precompression parameters were in acceptable range of pharmacopoeial specification. The disintegration time of optimized formulation (F3 was upto 48 sec. The in vitro release of Losartan Potassium was upto 15 min. The percentage relative bioavailability of Losartan Potassium from optimized sublingual tablets was found to be 144.7 %. Conclusions: Sublingual tablets of Losartan Potassium were successfully prepared with improved bioavailability.

  11. Transmission spectra study of sulfate substituted potassium dihydrogen phosphate

    KAUST Repository

    LI, LIANG

    2013-04-18

    Potassium dihydrogen phosphate (KDP) crystals with different amounts of sulfate concentration were grown and the transmittance spectrum was studied. A crystal with high sulfate replacement density exhibits heavy absorption property in the ultraviolet region which confirms and agrees well with former results. © 2013 Astro Ltd.

  12. Inhibition of large conductance calcium-dependent potassium ...

    African Journals Online (AJOL)

    We tested the hypothesis that Rho-kinase inhibits the large-conductance, calcium and voltage dependent potassium (BKCa) channels thereby promoting vasoconstriction. Our results show that the Rho-kinase inhibitor, Y-27632, induced concentration-dependent relaxation in rat mesenteric artery. The selective BKCa ...

  13. Superconductivity at 18 K in potassium-doped C60

    NARCIS (Netherlands)

    Hebard, A.F.; Rosseinsky, M.J.; Haddon, R.C.; Murphy, D.W.; Glarum, S.H.; Palstra, T.T.M.; Ramirez, A.P.; Kortan, A.R.

    1991-01-01

    The synthesis of macroscopic amounts of C60 and C70 (fullerenes) has stimulated a variety of studies on their chemical and physical properties. We recently demonstrated that C60 and C70 become conductive when doped with alkali metals. Here we describe low-temperature studies of potassium-doped C60

  14. Enhanced apparatus for AC Zeeman experiments with ultracold potassium

    Science.gov (United States)

    Rotunno, Andrew; Du, Shuangli; Fancher, Charles; Pyle, Andrew; Aubin, Seth

    2016-05-01

    Ultracold atomic potassium is an excellent candidate for studies of the AC Zeeman force, due to small hyperfine splittings. These experiments require a sufficient sample of potassium near an atom chip supporting RF currents, and an RF source which can make rapid phase-continuous frequency sweeps for fast manipulation of spin states. We present progress on the construction of laser amplifier system for improved laser cooling and trapping of potassium, development of a frequency-agile RF source, and research on RF-capable atom chips. The laser amplifier system consists of two tapered amplifiers for producing 0.4 W of 767 nm light, with a goal of collecting 107 potassium atoms at 100 μK, which will then be cooled sympathetically with ultracold rubidium. We have constructed a direct digital synthesizer (DDS) to produce 1-400 MHz with Hz-level linewidth and noise level below -60dBc, and the ability to produce fast 100 μs frequency sweeps. We are investigating atom chip designs for supporting large RF currents. Immediate applications include AC Zeeman potentials and traps for atom interferometry, and quantum many-body physics. Work supported by AFOSR, W&M, and in part by AFRL.

  15. Performance Evaluation of Refractory Composite Coatings in Potassium Rich Environment

    Directory of Open Access Journals (Sweden)

    Kristina BRINKIENĖ

    2016-09-01

    Full Text Available A laboratory scale method was used to study the performance of reinforced cement composites in potassium rich environment of biomass combustion. Buckwheat husk (BH was used as potential source of unexploited biomass product applicable as biomass derived fuel. In order to enhance the alkali effect on the properties of the investigated materials, the solution of potassium carbonate (K2CO3 was selected as potassium rich aggressive environment. Two reinforced cement composites as potential repair coatings for restoration of damaged refractory surfaces with different composition of aggregate were used in corrosion tests. Performance of refractory coatings was evaluated by analysing the microstructure of the treated composites as well as mechanical properties. Energy-dispersive X-ray spectroscopy (SEM/EDS and optical microscopy were used to study the microstructure in the corroded region of the refractory coatings. Long term studies in the solution of 1M K2CO3 for 56 months have demonstrated that composite with the additive of fluid cracking catalyst of oil refinery and petrochemical industries is more durable in the potassium rich environment.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.8348

  16. Toward a consensus model of the HERG potassium channel.

    NARCIS (Netherlands)

    Stary, A.; Wacker, S.J.; Boukharta, L.; Zachariae, U.G.; Karimi-Nejad, Y.; Aqvist, J.; Vriend, G.; Groot, B.L. de

    2010-01-01

    Malfunction of hERG potassium channels, due to inherited mutations or inhibition by drugs, can cause long QT syndrome, which can lead to life-threatening arrhythmias. A three-dimensional structure of hERG is a prerequisite to understand the molecular basis of hERG malfunction. To achieve a consensus

  17. Histopathologic effect of potassium bromate on the kidney of adult ...

    African Journals Online (AJOL)

    Objective: We aimed to demonstrate the histopathologic effects of potassium bromate (KBrO ) on the kidney tissues of rats following 3 short-term and long-term exposures. Method: Twenty young wistar rats of weights 180-250g were divided into three groups. The control group A was sub-divided into two groups of three rats ...

  18. Elevated potassium levels in patients with chronic kidney disease

    DEFF Research Database (Denmark)

    Thomsen, Reimar W; Nicolaisen, Sia K; Hasvold, Pål

    2018-01-01

    Background: Data on the true burden of hyperkalemia (HK) in patients with chronic kidney disease (CKD) in a real-world setting are scarce. Methods: The incidence rate of HK [first blood test with an elevated blood potassium level level >5.0 mmol/L] in primary or hospital care was assessed...

  19. Effect of different concentrations of potassium and magnesium on ...

    African Journals Online (AJOL)

    The rate of root colonization by mycorrhizal fungi largely depends on the concentration of nutrient elements in roots and soil. In this study, the effects of different concentrations of potassium and magnesium on mycorrhizal colonization of maize grown in pot cultures were studied. This experiment was performed using natural ...

  20. New nonabsorbable potassium-exchange resins in hyperkalaemia

    NARCIS (Netherlands)

    Roscioni, Sara S.; Lambers Heerspink, Hiddo

    New data suggest that treatment with patiromer or sodium zirconium cyclosilicate for up to 8 weeks reduces plasma potassium levels in hyperkalaemic patients. If proven safe and effective for long-term use, these therapies might be administered together with intensive renin-angiotensin-aldosterone

  1. Does Electroconvulsive therapy aggravate the rise in potassium and ...

    African Journals Online (AJOL)

    Background: Potassium and creatine kinase levels increase after the administration of suxamethonium. This rise may be exaggerated by the combination of suxamethonium fasciculation and the modified tonic/clonic convulsion induced by electroconvulsive therapy. This study compared the magnitude of increase in ...

  2. Effect of nitrogen and potassium fertilization on morpho-agronomic ...

    African Journals Online (AJOL)

    Elephant grass has been proposed for the energy sector as a possible source of renewable energy, because of its high biomass production. The aim of this study was to evaluate the effect of the mineral nutrients nitrogen and potassium on the morpho-agronomic traits (dry mater yield (DMY), percentage of DM (%DM), ...

  3. Characterization of verdete rock as a potential source of potassium

    Directory of Open Access Journals (Sweden)

    Wedisson Oliveira Santos

    2015-08-01

    Full Text Available Potassium is a nutrient found at low levels in Brazilian soils, requiring large inputs of fertilizers to achieve satisfactory crop yields. Brazil has high external dependence and limited reserves of soluble K mineral, which is traditionally exploited for the production of fertilizers. On the other hand, it is common the occurrence in the country of potassium-rich silicate minerals which are not commercially exploited. This study aimed to characterize mineralogically and chemically samples of verdete rock separated into size fractions and evaluate its potential as potassium fertilizer. The mineral composition of verdete rock is based on glauconite, quartz and feldspar. The total K2O content in verdete rock ranged from 5.18 to 9.0 dag/kg. The K content extracted in water or 2% citric acid was 2.4% below the total of K, indicating low reactivity of verdete rock and limitations for direct use as K source. The processes of physical fractionation and sedimentation in water are inefficient to promote the concentration of K in the different verdete rock fractions. The total K content in some samples are considerable and may enable the use of this rock as raw material for production of more reactive potassium fertilizers.

  4. 21 CFR 520.1696d - Penicillin V potassium tablets.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Penicillin V potassium tablets. 520.1696d Section 520.1696d Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES.... Treatment of respiratory, urogenital, skin and soft tissue infections and septicemia caused by pathogens...

  5. Effect of gibberellic acid and potassium nitrate on seed germination ...

    African Journals Online (AJOL)

    Ramonda serbica and Ramonda nathaliae are rare resurrection plants, endemic and relict species from Balkan Peninsula. The effect of gibberellic acid (GA3) and potassium nitrate (KNO3) were conducted to determine the seed germination response for these two species. An experiment was conducted with four ...

  6. 40 CFR 721.638 - Silyl amine, potassium salt (generic).

    Science.gov (United States)

    2010-07-01

    ...). 721.638 Section 721.638 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC... subject to reporting. (1) The chemical substance identified generically as silyl amine, potassium salt... A of this part apply to this section except as modified by this paragraph. (1) Recordkeeping...

  7. Effects of potassium behaviour in soils on crop absorption | Lin ...

    African Journals Online (AJOL)

    Potassium (K) is one of the three major elements that play important roles in plants, such as maintaining turgor of cells, promoting activation of enzymes, and improving efficiency of photosynthesis. The types of K in soil may affect the plant absorption of K. K in soils includes K minerals, K in layered silicates (clay minerals), ...

  8. The mutagenic potentials of potassium bromate and some ...

    African Journals Online (AJOL)

    GREGO

    2007-04-16

    Apr 16, 2007 ... This revealed that potassium bromate is mutagenic in bacteria and could be said to possess carcinogenic potentials. Key words: Food additives, E.coli, Ames spot assay, Mutant strains. INTRODUCTION. Food additives are substances added to preserve flavour or improve the taste and appearance of food.

  9. Characterization of potassium glycinate for carbon dioxide absorption purposes

    NARCIS (Netherlands)

    Portugal, A. F.; Derks, P. W. J.; Versteeg, G. F.; Magalhaes, F. D.; Mendes, A.

    2007-01-01

    Aqueous solutions of potassium glycinate were characterized for carbon dioxide absorption purposes. Density and viscosity of these solutions, with concentrations ranging from 0.1 to 3 M, were determined at temperatures from 293 to 313 K. Diffusivity of CO2 in solution was estimated applying the

  10. the effect of potassium bromate on some haematological parameters ...

    African Journals Online (AJOL)

    Daniel Owu

    wave hair solution (Ueno 2000). Potassium bromate is a substance that has a vapour density of 5.8 (air=1) and density of 3.27. (gcm3) and when in contact with combustible material may cause fire. It is incompatible with organics, reducing agents, aluminum, and finely powdered metals (USEPA 1993). When heated, it.

  11. Yield response of soybeans to levels of nitrogen and potassium ...

    African Journals Online (AJOL)

    A field trail was conducted at the University of Uyo Teaching and Research Farm in a high rainfall area of South eastern Nigeria to assess the yield response soybeans [ Glycine max (L.) Merrill ] to different levels of nitrogen and potassium fertilizers. The results showed that the number of pods/ plant, threshing percentage ...

  12. Syntheses, characterization and crystal structures of potassium and ...

    Indian Academy of Sciences (India)

    Syntheses, characterization and crystal structures of potassium and barium complexes of a Schiff base ligand with different anions. Bhavesh Parmar Kamal Kumar Bisht Pratyush Maiti Parimal Paul Eringathodi Suresh. Special issue on Chemical Crystallography Volume 126 Issue 5 September 2014 pp 1373-1384 ...

  13. Luminescence from potassium feldspars stimulated by infrared and green light

    DEFF Research Database (Denmark)

    Duller, G.A.T.; Bøtter-Jensen, L.

    1993-01-01

    A series of experiments are reported which investigate stimulated luminescence from potassium feldspar. The aim is to provide a basic phenomenological description of the response of the material to stimulation by heat, infrared radiation (875 DELTA 80 nm) and a green light wavelength band from 5 15...

  14. Synthesis and crystal structure of trinuclear potassium(I) complex ...

    African Journals Online (AJOL)

    A furazan-based trinuclear potassium(I) complex derived from the oxy-bridged bis(gem-dinitro)furazan (OBNF) and triaminoguanidinium (TGA) units was synthesized and characterized by elemental analyses, nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy. The single crystal X-ray structure of the ...

  15. Response of Cassava Variety TMS/98/0505 to Potassium ...

    African Journals Online (AJOL)

    Two field experiments were used to study the response of a low cyanide cassava variety TMS/98/0505 to potassium fertilizer and time of harvest in a tropical ultisol in south eastern Nigeria in 2005/06 and 2006/07. In each year, a split plot design was adopted for the experiment with treatments arranged in a randomized ...

  16. Syntheses, characterization and crystal structures of potassium and ...

    Indian Academy of Sciences (India)

    Syntheses, characterization and crystal structures of potassium and barium complexes of a Schiff base ligand with different anions. BHAVESH PARMARa, KAMAL KUMAR BISHTa,b, PRATYUSH MAITIc, PARIMAL PAULa,b, and ERINGATHODI SURESHa,b,∗. aAnalytical Discipline and Centralized Instrument Facility, ...

  17. Cloning and expression analysis of potassium channel gene NKT3 ...

    African Journals Online (AJOL)

    Potassium (K+) is the predominant inorganic ion of plant cells. K+ channels in higher plant cells play an important role in regulating the influx and efflux of K+ from cells, and activity of these channels might be involved in plant stress resistance. A completely new K+ channel gene of Nicotiana tabacum was obtained through ...

  18. ( Leveillula taurica ) on tomato by foliar sprays of liquid potassium ...

    African Journals Online (AJOL)

    A foliar application of soluble silicon (liquid potassium silicate) was tested for the control of powdery mildew of tomato for 2 years in the field conditions on susceptible cultivar Alida F1. Powdery mildew in field-grown staked tomato, caused by Leveillula taurica was significantly controlled by a foliar spray of either K2SiO3 or ...

  19. Acute toxicity of potassium permanganate to fingerlings of the ...

    African Journals Online (AJOL)

    Laboratory static bioassays were conducted to determine the 96-h LC50 and the lethal levels of concentrations of the aquaculture therapeutant, potassium permanganate (KMnO4) on fingerlings (mean weight, 6.24 ± 0.15 g and mean length, 4.25 ± 0.07 cm) of the African catfish, Clarias gariepinus. A total number of one ...

  20. Effect of Metformin on Potassium-adapted and Nonadapted Diabetic ...

    African Journals Online (AJOL)

    Purpose: To assess the effects of potassium adaptation on some biochemical parameters in diabetic rats treated with metformin. Methods: Diabetes was induced via intraperitoneal administration of streptozotocin in potassiumadapted and non-adapted rats and, then metformin (350 mg/kg) was administered orally.

  1. Mechanism of Proarrhythmic Effects of Potassium Channel Blockers

    DEFF Research Database (Denmark)

    Skibsbye, Lasse; Ravens, Ursula

    2016-01-01

    Any disturbance of electrical impulse formation in the heart and of impulse conduction or action potential (AP) repolarization can lead to rhythm disorders. Potassium (K(+)) channels play a prominent role in the AP repolarization process. In this review we describe the causes and mechanisms...

  2. Late termination of pregnancy by intracardiac potassium chloride ...

    African Journals Online (AJOL)

    Objectives. To report our experience with intracardiac potassium chloride (KCl) injection as a method of feticide for severe congenital abnormalities beyond 24 weeksf gestation. Method. A retrospective chart review. Patient demographics and types of fetal anomalies were analysed according to the groups that accepted

  3. Urinary sodium and potassium excretion, mortality, and cardiovascular events.

    Science.gov (United States)

    O'Donnell, Martin; Mente, Andrew; Rangarajan, Sumathy; McQueen, Matthew J; Wang, Xingyu; Liu, Lisheng; Yan, Hou; Lee, Shun Fu; Mony, Prem; Devanath, Anitha; Rosengren, Annika; Lopez-Jaramillo, Patricio; Diaz, Rafael; Avezum, Alvaro; Lanas, Fernando; Yusoff, Khalid; Iqbal, Romaina; Ilow, Rafal; Mohammadifard, Noushin; Gulec, Sadi; Yusufali, Afzal Hussein; Kruger, Lanthe; Yusuf, Rita; Chifamba, Jephat; Kabali, Conrad; Dagenais, Gilles; Lear, Scott A; Teo, Koon; Yusuf, Salim

    2014-08-14

    The optimal range of sodium intake for cardiovascular health is controversial. We obtained morning fasting urine samples from 101,945 persons in 17 countries and estimated 24-hour sodium and potassium excretion (used as a surrogate for intake). We examined the association between estimated urinary sodium and potassium excretion and the composite outcome of death and major cardiovascular events. The mean estimated sodium and potassium excretion was 4.93 g per day and 2.12 g per day, respectively. With a mean follow-up of 3.7 years, the composite outcome occurred in 3317 participants (3.3%). As compared with an estimated sodium excretion of 4.00 to 5.99 g per day (reference range), a higher estimated sodium excretion (≥ 7.00 g per day) was associated with an increased risk of the composite outcome (odds ratio, 1.15; 95% confidence interval [CI], 1.02 to 1.30), as well as increased risks of death and major cardiovascular events considered separately. The association between a high estimated sodium excretion and the composite outcome was strongest among participants with hypertension (P=0.02 for interaction), with an increased risk at an estimated sodium excretion of 6.00 g or more per day. As compared with the reference range, an estimated sodium excretion that was below 3.00 g per day was also associated with an increased risk of the composite outcome (odds ratio, 1.27; 95% CI, 1.12 to 1.44). As compared with an estimated potassium excretion that was less than 1.50 g per day, higher potassium excretion was associated with a reduced risk of the composite outcome. In this study in which sodium intake was estimated on the basis of measured urinary excretion, an estimated sodium intake between 3 g per day and 6 g per day was associated with a lower risk of death and cardiovascular events than was either a higher or lower estimated level of intake. As compared with an estimated potassium excretion that was less than 1.50 g per day, higher potassium excretion was

  4. Nutritional and taste characteristics of low-potassium lettuce developed for patients with chronic kidney diseases

    OpenAIRE

    Yoshida, Takuya; Sakuma, Kozue; Kumagai, Hiromichi

    2014-01-01

    Dietary potassium restriction is recommended for chronic kidney disease (CKD) patients with hyperkalemia. Boiling or soaking vegetables in water is known to decrease their potassium content. However, these methods can also reduce the quantity of other nutrients. Recently, low-potassium (LK) lettuce has been developed for CKD patients with hyperkalemia. This study compared the potassium content, other nutritional values, and taste characteristics of LK lettuce with those of normal lettuce. The...

  5. Kinetics and Mechanism of the Oxidation of Menthol by Potassium Bromate in Acidic Solution

    OpenAIRE

    Ravikant na; Ms. Meena; Shrikant Sharma

    2014-01-01

    No suitable method is available for the estimation of menthol, hence in all kinetic results reported in this chapter, menthol was in excess over potassium bromate and the stoichiometry was also determined under the experimental conditions where menthol (substrate) was in excess over potassium bromate (oxidant). Present study was focused on the analysis of kinetics and mechanism of oxidation of neomenthol by potassium bromate in acidic medium. For oxidizing neomenthol, potassium bromate stock ...

  6. Kinetics and Mechanism of the Oxidation of Neomenthol by Potassium Bromate in Acidic Solution

    OpenAIRE

    Ravikant na

    2014-01-01

    Present study was focused on the analysis of kinetics and mechanism of oxidation of neomenthol by potassium bromate in acidic medium. For oxidizing neomenthol, potassium bromate stock solution (5.0×10─2 mol. dm─3) was prepared by dissolving exactly weighed quantity of potassium bromate in doubly distilled water. The suitable reaction mixtures were prepared and left at 313 K for over 24 hours to ensure complete oxidation of neomenthol15. The unreacted potassium bromate was determined iodometri...

  7. Glycyrrhetinic acid decreases plasma potassium concentrations in patients with anuria.

    Science.gov (United States)

    Serra, Andreas; Uehlinger, Dominik E; Ferrari, Paolo; Dick, Bernhard; Frey, Brigitte M; Frey, Felix J; Vogt, Bruno

    2002-01-01

    ABSTRACT. Licorice-associated hypertension is thought to be due to increased renal sodium retention. The active compound of licorice, glycyrrhetinic acid (GA), inhibits renal 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) and by that mechanism increases access of cortisol to the mineralocorticoid receptor that causes renal sodium retention and potassium loss. In addition, a direct vascular effect of 11beta-HSD activity has recently been incriminated to promote hypertension, a contention based on in vitro observations. This investigation was designed to establish whether this extrarenal effect of 11beta-HSD is relevant for BP regulation and potassium concentrations in plasma. In a prospective, double-blind, cross-over study, seven patients with anuria on chronic hemodialysis were randomly assigned after a baseline period of 2 wk to placebo or GA (1 g/d) for 2 wk, separated by a washout phase of 3 wk. The ratio of plasma cortisol/cortisone, determined by gas chromatography-mass spectrometry, increased in all patients after GA intake (F = 9.705; P < 0.004), which indicates inhibition of 11beta-HSD. Twenty-four-hour BP values did not change throughout the study. The increase of the plasma cortisol/cortisone ratio was paralleled by a decline in the plasma potassium concentration in every patient. The mean +/- SD plasma potassium concentration decreased from 5.5 +/- 0.6 mM/L at baseline to 4.9 +/- 0.7 and 4.5 +/- 0.8 mM/L after 1 and 2 wk on GA, respectively (F = 9.934, P < 0.003). Extrarenal 11beta-HSD activity influences serum potassium concentrations but does not regulate BP independently of renal sodium retention.

  8. 21 CFR 520.1696b - Penicillin G potassium in drinking water.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Penicillin G potassium in drinking water. 520....1696b Penicillin G potassium in drinking water. (a) Specifications. When reconstituted, each milliliter contains penicillin G potassium equivalent to 20,000, 25,000, 40,000, 50,000, 80,000, or 100,000 units of...

  9. 40 CFR 180.1177 - Potassium bicarbonate; exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Potassium bicarbonate; exemption from... FOOD Exemptions From Tolerances § 180.1177 Potassium bicarbonate; exemption from the requirement of a tolerance. The biochemical pesticide potassium bicarbonate is exempted from the requirement of a tolerance...

  10. Availability and Release Kinetics of Nonexchangeable Potassium in Some Calcareous Soils of Fars Province

    Directory of Open Access Journals (Sweden)

    S. Abdi

    2014-12-01

    Full Text Available Sum of exchangeable and solution forms of soil potassium is widely used to determine potassium availability for plants. Reliability of these methods is not enough in soils that contain 2:1 phyllosilicates. Additional to exchangeable potassium, nonexchamgeable potassium also has an important role in plant nutrition. Limited information about availability and release kinetics of nonexchangeable potassium in calcareous soils of Fars province is available. For this purpose, some extractants including ammonium acetate, boiling nitric acid, 0.1M nitric acid, 2M sodium chloride and water were evaluated to prediction of potassium availability for corn in 10 calcareous soils of Fars province. Release kinetics of nonexchangeable potassium was studied using 15 successive 15-min extraction with 0.01M calcium chloride. Kinetics models describing nonexchangeable potassium release rate including zero order, first order, second order, third order, parabolic diffusion, power function and ellovich were evaluated. Results showed that 1M neutral amonium acetate, 0.1M aitric acid, water and 2M sodium chloride extractants had high correlation with corn potassium uptake. Amount of potassium released among studied soils was vary in the range of 243 to 814 mg kg-1. According to R2 and SE, kinetics of nonexchangeable potassium release was described with power function, parabolic diffusion and ellovich equations satisfactorily. According to this fact that constant rate of parabolic diffusion and ellovich models had significant correlations with corn potassium uptake, it is recommended that these two models are suitable for use in these studied soils.

  11. 40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

    Science.gov (United States)

    2010-07-01

    ...) derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection of Environment...) derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant new uses subject...) derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is subject to reporting under this section...

  12. Blood pressure response to changes in sodium and potassium intake: a metaregression analysis of randomised trials

    NARCIS (Netherlands)

    Geleijnse, J.M.; Kok, F.J.; Grobbee, D.E.

    2003-01-01

    The objective of the study was to assess the blood pressure response to changes in sodium and potassium intake and examine effect modification by age, gender, blood pressure, body weight and habitual sodium and potassium intake. Randomised trials of sodium reduction or potassium supplementation and

  13. POTASSIUM CHANNELS IN HYPOKALEMIC PERIODIC PARALYSIS - A KEY TO THE PATHOGENESIS

    NARCIS (Netherlands)

    LINKS, TP; SMIT, AJ; OOSTERHUIS, HJGH; REITSMA, WD

    1. A possible role for the ATP-sensitive potassium channels in the pathogenesis of hypokalaemic periodic paralysis was investigated. 2. We assessed insulin release and muscle strength after intravenous glucose loading with and without the potassium channel opener pinacidil and the potassium channel

  14. [Assessment of total body potassium and water for therapeutic control of maldigestion syndromes (author's transl)].

    Science.gov (United States)

    Lehr, L; Schober, O; Pichlmayr, R

    1980-01-01

    Severe intracellular potassium depletion was found with maldigestion (short bowel, high output fistula, M. Crohn, colitis ulcerativa) when total body potassium and water measurement were taken. Serum potassium levels were misleading. These methods are of particular value in planning and conducting a preoperative infusion therapy to correct the documented deficit.

  15. [Effects of different potassium fertilizer application periods on the yield and quality of Fuji apple].

    Science.gov (United States)

    Lu, Yong-li; Yang, Xian-long; Li, Ru; Li, Shui-li; Tong, Yan-an

    2015-04-01

    In order to ascertain the effects of potassium fertilizer application periods on apple production, we conducted a field experiment and analyzed the differences in apple yield, fruit quality, potassium fertilizer use efficiency, and nutrient concentrations in leaves and fruits among treatments with differences in timing of potassium application. The results indicated that, compared with no potassium-applied treatment (CK), all potassium fertilizer application treatments significantly increased the apple yield by 4.3%-33.2%, meanwhile, it also obviously improved the fruit quality. In comparison with the application of 100% potassium fertilizer as a base, the application of 50% or 100% of potassium fertilizer at the fruit enlargement stage (the remaining 50% applied as a base or after flowering) significantly increased the apple yield by 20.5% - 27.7% and improved the fruit quality. Compared with the application 100% potassium fertilizer at the stage of fruit enlargement, the evenly split application as base flowering stage and at the fruit enlargement: stage not only contributed to a higher yield, better quality and higher potassium use efficiency, but also maintained a relatively stable potassium concentration level in leaves. However, the split potassium fertilizer application at the flowering and fruit enlargement stages resulted in the significant decrease in concentration of calcium in fruit, which would be negative to fruit quality. In conclusion, our research suggested that evenly split application of potassium fertilizer as a base and at the fruit enlargement stage was the suitable period for apple production in Fuji apple orchards in this region.

  16. Impact of potassium iodide on thyroidectomy for Graves' disease: Implications for safety and operative difficulty.

    Science.gov (United States)

    Randle, Reese W; Bates, Maria F; Long, Kristin L; Pitt, Susan C; Schneider, David F; Sippel, Rebecca S

    2018-01-01

    Potassium iodide often is prescribed prior to thyroidectomy for Graves' disease, but the effect of potassium iodide on the ease and safety of thyroidectomy for Graves' is largely unknown. We conducted a prospective, cohort study of patients with Graves' disease undergoing thyroidectomy. For the first 8 months, no patients received potassium iodide; for the next 8 months, potassium iodide was added to the preoperative protocol for all patients. Outcomes included operative difficulty (based on the Thyroidectomy Difficulty Scale) and complications. We included a total of 31 patients in the no potassium iodide group and 28 in the potassium iodide group. According to the Thyroidectomy Difficulty Scale, gland vascularity decreased in the potassium iodide group (mean score 2.6 vs 3.3, P = .04), but there were no differences in friability, fibrosis, or size of the thyroid or in overall difficulty of operation (P = not significant for all). Despite similar operative difficulty, patients prescribed potassium iodide were less likely to experience transient hypoparathyroidism (7% vs 26%, P = .018) and transient hoarseness (0% vs 16%, P = .009) compared with the no potassium iodide group. Potassium iodide administration decreases gland vascularity, but does not change the overall difficulty of thyroidectomy. Preoperative use of potassium iodide solution was, however, associated with less transient hypoparathyroidism and transient hoarseness, suggesting that potassium iodide improves the safety of thyroidectomy for Graves' disease. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. 40 CFR 415.110 - Applicability; description of the potassium metal production subcategory.

    Science.gov (United States)

    2010-07-01

    ... potassium metal production subcategory. 415.110 Section 415.110 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Potassium Metal Production Subcategory § 415.110 Applicability; description of the potassium metal production subcategory. The provisions of this subpart are applicable to discharges...

  18. 40 CFR Appendix A to Part 425 - Potassium Ferricyanide Titration Method

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Potassium Ferricyanide Titration... Appendix A to Part 425—Potassium Ferricyanide Titration Method Source The potassium ferricyanide titration... faded to a pale yellow, and continue the titration to the disappearance of the blue color. Calculate the...

  19. Changes in urinary potassium excretion in patients with chronic kidney disease

    Directory of Open Access Journals (Sweden)

    Yuichiro Ueda

    2016-06-01

    Conclusion: This study demonstrated that urinary potassium excretion decreased with reductions in renal function. Furthermore, urinary potassium excretion was mainly affected by urinary sodium excretion and estimated glomerular filtration rate in patients with CKD, whereas the presence of diabetes mellitus and use of renin–angiotensin–aldosterone system inhibitors were not associated with urinary potassium excretion in this study.

  20. Potassium homeostasis during exercise in domestic species: the role of the sodium-potassium pump in skeletal muscle

    NARCIS (Netherlands)

    Everts, Maria E.

    2001-01-01

    In 1997, Jens Christian Skou was awarded the Nobel prize in Chemistry for his discovery and elegant description, some 40 years earlier, of the sodium-potassium (Na+,K+) pump in crab nerve fibres [37]. It is now widely accepted that this cation transport system is essential for cell function, and