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1

Preparation of aluminum-doped zinc oxide (AZO) nano particles by hydrothermal synthesis  

Microsoft Academic Search

Aluminum doped zinc oxide (AZO) nanometric particles were synthesized by hydrothermal method. Aluminum nitrate hydrate, aluminum\\u000a sec-butoxide and zinc nitrate hydrate were used as the starting materials, and n-propanol and 2-butanol were used as solvents.\\u000a Ratio of Al2O3 in ZnO was kept at 10 wt%. Reaction was conducted in a Teflon autoclave at 175–225 °C for 5 h. Ratios of alcohol, H2O

Esin Burunkaya; Nadir Kiraz; Ömer Kesmez; H. Erdem Çamurlu; Meltem Asiltürk; Ertu?rul Arpaç

2010-01-01

2

Electrical properties of aluminum-doped zinc oxide (AZO) nanoparticles synthesized by chemical vapor synthesis  

NASA Astrophysics Data System (ADS)

Aluminum-doped zinc oxide nanoparticles have been prepared by chemical vapor synthesis, which facilitates the incorporation of a higher percentage of dopant atoms, far above the thermodynamic solubility limit of aluminum. The electrical properties of aluminum-doped and undoped zinc oxide nanoparticles were investigated by impedance spectroscopy. The impedance is measured under hydrogen and synthetic air between 323 and 673 K. The measurements under hydrogen as well as under synthetic air show transport properties depending on temperature and doping level. Under hydrogen atmosphere, a decreasing conductivity with increasing dopant content is observed, which can be explained by enhanced scattering processes due to an increasing disorder in the nanocrystalline material. The temperature coefficient for the doped samples switches from positive temperature coefficient behavior to negative temperature coefficient behavior with increasing dopant concentration. In the presence of synthetic air, the conductivity firstly increases with increasing dopant content by six orders of magnitude. The origin of the increasing conductivity is the generation of free charge carriers upon dopant incorporation. It reaches its maximum at a concentration of 7.7% of aluminum, and drops for higher doping levels. In all cases, the conductivity under hydrogen is higher than under synthetic air and can be changed reversibly by changing the atmosphere.

Hartner, Sonja; Ali, Moazzam; Schulz, Christof; Winterer, Markus; Wiggers, Hartmut

2009-11-01

3

Electrical properties of aluminum-doped zinc oxide (AZO) nanoparticles synthesized by chemical vapor synthesis.  

PubMed

Aluminum-doped zinc oxide nanoparticles have been prepared by chemical vapor synthesis, which facilitates the incorporation of a higher percentage of dopant atoms, far above the thermodynamic solubility limit of aluminum. The electrical properties of aluminum-doped and undoped zinc oxide nanoparticles were investigated by impedance spectroscopy. The impedance is measured under hydrogen and synthetic air between 323 and 673 K. The measurements under hydrogen as well as under synthetic air show transport properties depending on temperature and doping level. Under hydrogen atmosphere, a decreasing conductivity with increasing dopant content is observed, which can be explained by enhanced scattering processes due to an increasing disorder in the nanocrystalline material. The temperature coefficient for the doped samples switches from positive temperature coefficient behavior to negative temperature coefficient behavior with increasing dopant concentration. In the presence of synthetic air, the conductivity firstly increases with increasing dopant content by six orders of magnitude. The origin of the increasing conductivity is the generation of free charge carriers upon dopant incorporation. It reaches its maximum at a concentration of 7.7% of aluminum, and drops for higher doping levels. In all cases, the conductivity under hydrogen is higher than under synthetic air and can be changed reversibly by changing the atmosphere. PMID:19801771

Hartner, Sonja; Ali, Moazzam; Schulz, Christof; Winterer, Markus; Wiggers, Hartmut

2009-10-05

4

Zinc Oxide Stabilized Zirconia.  

National Technical Information Service (NTIS)

Zinc oxide stabilized zirconia containing zirconia in cubic phase is prepared by evaporating zirconia and zinc oxide and depositing zirconia and zinc oxide on an atomic scale on a substrate. The stabilized zirconia resists corrosion at high temperatures a...

S. B. Qadri E. F. Skelton P. Lubitz

1997-01-01

5

Some special phenomena observed from in-line sputtered aluminum doped zinc oxide films  

Microsoft Academic Search

In-line sputtered aluminum doped zinc oxide (AZO) films with different substrate temperature have been made. Anisotropic stress of AZO films produced during in-line sputtering was proposed before. This work reports more special phenomena observed from in-line sputtered AZO films attributed to anisotropic stress effect. Three different types of AZO films' surface morphology: a. rounded grain and nearly uniform grain size,

Shang-Chou Chang; Gu-Wei Jian; Sheng-Han Huang; To-Sing Li; Tien-Chai Lin

2010-01-01

6

Zinc oxide overdose  

MedlinePLUS

Zinc oxide is an ingredient in many products, including certain creams and ointments used to prevent or treat minor skin burns and irritation. Zinc oxide overdose occurs when someone accidentally or intentionally ...

7

Development of Novel Aluminum-Doped Zinc Oxide Film and Its Application to Solar Cells  

NASA Astrophysics Data System (ADS)

We have developed novel aluminum-doped zinc oxide films (AZO-X and AZO-HX films) with a high haze value using wet-chemical etching for various times after dc magnetron sputtering, and have investigated their electrical and optical properties, durability under high-humidity condition, and surface morphology. The AZO-X and AZO-HX films showed good balance between transmittance in the near-infrared area and durability under 85 °C--85%RH condition. These novel films also had a higher haze value after wet chemical etching than normal AZO films. The crater size and haze value of the AZO-HX film increased with increasing etching time in comparison with those of the AZO-X film. The haze value of the AZO-HX film was higher than that of the AZO-X film; their values are 90% at 550 nm and 60% at 800 nm. Furthermore, the AZO-HX film was applied in amorphous silicon (a-Si) single-type solar cells as the front electrode. The short-circuit current of the solar cell using the AZO-HX film was higher than that of the solar cell using the AZO-X film. As an optimization-based result, an efficiency as high as 10.2% was obtained, showing that the new AZO-HX film is a promising material for the front electrode of a-Si solar cells.

Kuramochi, Hideto; Akiike, Ryo; Iigusa, Hitoshi; Tamano, Kimiaki; Utsumi, Kentaro; Shibutami, Tetsuo; Sichanugrist, Porponth; Konagai, Makoto

2012-10-01

8

Highly transparent polymer light-emitting diode using modified aluminum-doped zinc oxide top electrode  

NASA Astrophysics Data System (ADS)

We report a novel approach that leads to a significant improvement in the performance of transparent polymer light-emitting diodes (TPLEDs). By introducing a solution-based titanium oxide (TiOx) layer, we have demonstrated that the device performance of TPLEDs using aluminum-doped zinc oxide (AZO) top electrodes is enhanced. The TiOx layer lowers the energy barrier between the luminescent polymer and the AZO top electrode by modifying the WF of the top AZO electrodes. Moreover, the TiOx layer prevents the damage caused by UV radiation and by highly energetic ions generated during the AZO sputtering.

Heum Park, Sung; Hoon Lee, Byoung; Moon Shin, Jong; Jeong, Se-Young; Song, Suhee; Suh, Hongsuk; Lee, Kwanghee

2012-03-01

9

An Evaluation of Zinc Oxide Photovoltaic Devices  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) is attractive for photovoltaic applications due to its conductivity when doped with aluminum and transparency to the visible range of sunlight, i.e. minimized optical and electrical loss. Zinc oxide can form a stable n-n isotype heterojunction with silicon, which is comparable with conventional p-n junctions. The performance of such a junction heavily relies on the Fermi energy tuning of ZnO by Al doping. As an n-type dopant to ZnO, Al greatly improves the conductivity of ZnO. Moreover, Al-doped ZnO (AZO) is relatively abundant and cheap compared to other transparent conductive oxides (TCO), so that potentially the cost of electricity generation ($/KW) can be decreased. In order to boost the poor open circuit voltages resulted from the structures such as ITO/n-Si and AZO/n-Si, a thin 40 nm AZO film was introduced in our design as a buffer layer between the emitter and base. Our goal is to discover what Al content in the buffer layer achieves the optimum performance. Aluminum doped ZnO films were grown by a co-sputtering method which was a combination of RF sputtered ZnO with a fixed power of 300 W and DC sputtered Al with varied powers of 15-40 W. The Al content in AZO increases with increasing power used in Al sputtering. In this research, two types of heterojunction solar cells, ITO/AZO/n-Si and AZO/AZO/n-Si, were fabricated, analyzed and compared. The middle layer of AZO is the buffer layer which has varied Al doping and plays a key role in improving open circuit voltage. For the structure AZO/AZO/n-Si, the top emitter AZO layer has a fixed Al doping of 6.12 wt% at which AZO demonstrates the highest conductivity. With Al doping of the buffer AZO layer ranging from 0-7 wt.%, 6.34 wt.% of Al doping yields the best performance for both types of solar cell structures. At its best performance, ITO/AZO/n-Si demonstrates an open circuit voltage (Voc) of 0.42 V, a short circuit current density (J sc) of 26.0 mA/cm2, and a conversion efficiency of 5.03%, while AZO/AZO/n-Si shows a Voc of 0.3 V, a Jsc of 24.7 mA/cm2 and a conversion efficiency of 3.99%. The device ITO/AZO/n-Si which has 6.34% Al doped ZnO buffer improves the Voc up to 0.42V from 0.2V for the cell without a ZnO buffer layer. Similarly, AZO/AZO/n-Si improves the Voc to 0.3 V from 0.26 V for the cell without a buffer layer. The research results have shown that both types of structure provide higher Voc than the structure without a buffer layer. The increase of Voc can be attributed to the fact that the buffer layer engineers the Fermi level of ZnO to heighten the isotype junction barrier. Our capacitance-voltage (C-V) measurements showed that the junction formed with ZnO and intrinsic Si has the highest barrier height compared to ZnO/nSi or ZnO/pSi junctions. This could imply that reducing the doping density of Si can possibly improve the barrier height at the ZnO/Si interface and therefore improve the open-circuit voltage. To study the carrier transport mechanisms at ZnO/nSi junctions, current-voltage-temperature (I-V-T) measurements were conducted. As a result, in the forward direction, AZO(6.34 wt%)/nSi junction shows a combination of thermionic emission and recombination at intermediate voltages and an existence of space charge limited current (SCLC) at high voltages. On the other hand, AZO(3.49 wt%)/nSi junction has a mechanism of a combination of tunneling and recombination at intermediate voltages and SCLC in the ballistic regime at high voltages.

Wang, Jun

10

Emerging photoluminescence in azo-pyridine intercalated graphene oxide layers  

NASA Astrophysics Data System (ADS)

Inspite of being a potential material for electronic applications graphene possesses very poor optical properties, which need to be modified to make it suitable for optoelectronic devices. To achieve superior optical properties, graphene oxide (GO) sheets are functionalized with azo-pyridine to form a new intercalated structure with an interlayer separation of 0.9 nm. These azo-pyridine intercalated GO sheets show superior optical properties with bright blue emission via excited state intra-molecular proton transfer (ESIPT) which have potential applications in graphene based optoelectronic devices.

Gupta, Abhisek; Saha, Shyamal K.

2012-09-01

11

Process for making hydrogen. [reduction of zinc oxide; reaction of zinc and steam; recycling zinc oxide  

Microsoft Academic Search

A process for making hydrogen is described which comprises reducing zinc oxide to zinc metal, combining the metallic zinc with molten lead and spraying the mixture under pressure to an oxidizer where metallic zinc is reacted with steam to yield hydrogen and zinc oxide, separating the hydrogen product under pressure, separating the zinc oxide from the molten lead, recycling zinc

Seitzer

1975-01-01

12

Reductive cleavage of azo compounds catalyzed by commercial zinc dust using ammonium formate or formic acid  

Microsoft Academic Search

Azo compounds, both symmetric and unsymmetric, are cleaved to amine(s) by using commercial zinc dust and ammonium formate or formic acid in methanol, tetrahydrofuran or dioxane at room temperature. The reductive cleavage occurs without hydrogenolysis or hydrogenation of reducible moieties, such as -OH, -CH3, -OCH3, -COOH, -COCH3, halogen, etc. The cleavage is very fast, clean, cost effective and high-yielding if

Shankare Gowda; K Abiraj; D. Channe Gowda

2002-01-01

13

The effects of oxygen vacancies in space stable aluminum-doped zinc oxide thin films  

Microsoft Academic Search

Polycrystalline ZnO:Al (AZO) thin films are routinely deposited by RF magnetron sputtering. The figures of merit, resistivity (rho) and transmittance (T), of AZO films deposited using an oxide target are heavily dependent upon residual water vapor within the growth chamber Zinc oxide is an inherently n-type material in which the oxygen vacancy (VO) is the main donor defect. The substitution

Craig M. Lennon

2010-01-01

14

Effect of Substrate Temperature on Optical Properties of Aluminum Zinc Oxide Thin Films Deposited by DC Magnetron Sputtering  

Microsoft Academic Search

In the present work Aluminum doped Zinc Oxide (AZO) thin films have been deposited on glass substrates from room temperature to 300°C by direct current (d.c) magnetron sputtering. The effects of substrate temperature on the crystallization behavior and optical properties of the films have been studied. The optical transmittance of aluminum zinc oxide films are obviously influenced by the substrate

B. Rajesh Kumar; T. Subba Rao

2011-01-01

15

Doped zinc oxide microspheres  

DOEpatents

A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

Arnold, Jr., Wesley D. (Oak Ridge, TN); Bond, Walter D. (Knoxville, TN); Lauf, Robert J. (Oak Ridge, TN)

1993-01-01

16

Doped zinc oxide microspheres  

DOEpatents

A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel. 4 figures.

Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

1993-12-14

17

Near-perfect infrared absorption from dielectric multilayer of plasmonic aluminum-doped zinc oxide  

NASA Astrophysics Data System (ADS)

We demonstrated a near-perfect infrared absorber by using nanostructure multilayer of aluminum doped zinc oxide (AZO) and ZnO. The negative real part of permittivity of AZO allows the dielectric multilayer to match the phase of all light reflected. The field amplitudes destructive interference leads to a reflectance closing to zero at ~1.90 ?m. Both experimental and theoretical investigations indicated that the multilayer simultaneously minimized reflectance and transmittance in infrared region, leading to a high absorptance of ~99% at ~1.90 ?m. These AZO metamaterials will bring more opportunities for simplified fabrications and something new towards plasmonics and artificial optics.

Zhang, Yun; Wei, Tiaoxing; Dong, Wenjing; Huang, Chanyan; Zhang, Kenan; Sun, Yan; Chen, Xin; Dai, Ning

2013-05-01

18

An anode with aluminum doped on zinc oxide thin films for organic light emitting devices  

Microsoft Academic Search

Doped zinc oxides are attractive alternative materials as transparent conducting electrode because they are nontoxic and inexpensive compared with indium tin oxide (ITO). Transparent conducting aluminum-doped zinc oxide (AZO) thin films have been deposited on glass substrates by DC reactive magnetron sputtering method. Films were deposited at a substrate temperature of 150?°C in 0.03 Pa of oxygen pressure. The electrical

Denghui Xu; Zhenbo Deng; Ying Xu; Jing Xiao; Chunjun Liang; Zhiliang Pei; Chao Sun

2005-01-01

19

Catalytic Transfer Hydrogenation of Azo Compounds to Hydrazo Compounds Using Inexpensive Commercial Zinc Dust and Hydrazinium Monoformate  

Microsoft Academic Search

Azo compounds are conveniently reduced to hydrazo compounds by using commercial zinc dust and hydrazinium monoformate at room temperature. Many reducible and hydrogenolysable groups like OCH3, OC2H5, OH, COOH, CH3, SO3Na and halogens are tolerated. The reduction is fast, clean, high?yielding and inexpensive.

H. S. Prasad; Shankare Gowda; K. Abiraj; D. Channe Gowda

2003-01-01

20

The oxidation of acid azo dye AY 36 by a manganese oxide containing mine waste.  

PubMed

The oxidative breakdown of acid azo dye acid yellow 36 (AY 36) by a Mn oxide containing mine tailings is demonstrated. The oxidation reaction is pH dependent with the rate of decolorization increasing with decreasing pH. The oxidation reaction mechanism is initiated at the amino moiety and proceeds via successive, one electron transfers from the dye to the Mn oxide minerals. The reaction pathway involves the formation of a number of colorless intermediate products, some of which hydrolyze in a Mn oxide-independent step. Decolorization of the dye is rapid and is observed before the cleavage of the azo-bond, which is a slower process. The terminal oxidation products were observed to be p-benzoquinone and 3-hydroxybenzenesulfonate. The reaction order of the initial decolorization was determined to be pseudo fractional order with respect to pH and pseudo first order with respect to dye concentration and Mn tailings' surface area. PMID:23333488

Clarke, Catherine E; Kielar, Filip; Johnson, Karen L

2012-12-20

21

High rate direct current magnetron sputtered and texture-etched zinc oxide films for silicon thin film solar cells  

Microsoft Academic Search

Aluminum-doped zinc oxide (AZO) films were prepared by in-line direct current (dc) magnetron sputtering on glass substrates. Four types of ceramic targets with 0.5 wt.% or 1 wt.% of aluminum oxide and different preparation methods, namely normal sintered, soft sintered and hot pressed, were employed. The influence of different target manufacturing processes, aluminum concentration and sputtering conditions on AZO films were investigated.

T. Tohsophon; J. Hupkes; H. Siekmann; B. Rech; M. Schultheis; N. Sirikulrat

2008-01-01

22

Characterization of Monolayer Formation on Aluminum-Doped Zinc Oxide Thin Films  

SciTech Connect

The optical and electronic properties of aluminum-doped zinc oxide (AZO) thin films on a glass substrate are investigated experimentally and theoretically. Optical studies with coupling in the Kretschmann configuration reveal an angle-dependent plasma frequency in the mid-IR for p-polarized radiation, suggestive of the detection of a Drude plasma frequency. These studies are complemented by oxygen depletion density functional theory studies for the calculation of the charge carrier concentration and plasma frequency for bulk AZO. In addition, we report on the optical and physical properties of thin film adlayers of n-hexadecanethiol (HDT) and n-octadecanethiol (ODT) self-assembled monolayers (SAMs) on AZO surfaces using reflectance FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), contact angle, and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Our characterization of the SAM deposition onto the AZO thin film reveals a range of possible applications for this conducting metal oxide.

Rhodes,C.; Lappi, S.; Fischer, D.; Sambasivan, S.; Genzer, J.; Franzen, S.

2008-01-01

23

Synthesis of nano-sized powders of transparent conductive aluminum-doped zinc oxide by electrolysis-modified co-precipitation method  

Microsoft Academic Search

Nano-sized powders of transparent conductive aluminum-doped zinc oxide (AZO) have been successfully prepared by electrolysis-modified co-precipitation method. By adding ammonium hydroxide into the precursor solution prepared by electrolytic dissolution of zinc metal in a buffered electrolyte solution of nitric acid and ammonium nitrate with adequate addition of aluminum nitrate, co-precipitate precursors of AZO with particle size between 30 to 60

Hsin-Chun Lu; Chen-Sung Chang; Chia-Wei Li; Yu-Shiang Lin; Chun-Lung Chu; Chi-you Lai

2008-01-01

24

Crystal orientation dependent thermoelectric properties of highly oriented aluminum-doped zinc oxide thin films  

NASA Astrophysics Data System (ADS)

We demonstrate that the thermoelectric properties of highly oriented Al-doped zinc oxide (AZO) thin films can be improved by controlling their crystal orientation. The crystal orientation of the AZO films was changed by changing the temperature of the laser deposition process on LaAlO3 (100) substrates. The change in surface termination of the LaAlO3 substrate with temperature induces a change in AZO film orientation. The anisotropic nature of electrical conductivity and Seebeck coefficient of the AZO films showed a favored thermoelectric performance in c-axis oriented films. These films gave the highest power factor of 0.26 W m-1 K-1 at 740 K.

Abutaha, A. I.; Sarath Kumar, S. R.; Alshareef, H. N.

2013-02-01

25

Self-assembled monolayers assisted thin film growth of aluminum doped zinc oxide by spray pyrolysis method  

NASA Astrophysics Data System (ADS)

In this work, aluminum doped zinc oxide (AZO) were deposited on pristine and self-assembled monolayer (SAM) modified glass substrates by chemical spray pyrolysis technique. The measurements of different parameters showed that modifying the surface of the glass substrates with the different SAMs resulted in excellent nucleation sites for the crystal growth of the AZO thin film. Among the different functional groups, SAMs with CH3 terminal group improves the quality of the film remarkably, while the other groups improve the quality moderately. From the results we observed that our finding suggests a novel approach of improving the quality of AZO films deposited by spray pyrolysis technique.

Aklilu, Muluken; Tai, Yian

2013-04-01

26

Comparative study of sol–gel derived tin-doped indium- and aluminum-doped zinc-oxide coatings for electrical conducting and low-emitting surfaces  

Microsoft Academic Search

Cost-efficient transparent conductive oxide (TCO) compounds based on doped zinc oxide (e.g. aluminum zinc oxideAZO) have been investigated in addition to the well-established functional coatings of doped indium oxide (e.g. indium tin oxide – ITO). The electrical, morphological and optical properties of both types of coatings are compared. For the deposition of transparent conductive oxides, such as tin-doped

M. Rydzek; M. Reidinger; M. Arduini-Schuster; J. Manara

2011-01-01

27

A zinc oxide microwire laser  

Microsoft Academic Search

In this paper, we report stimulated emission from a zinc oxide (ZnO) microcrystal grown by carbothermal evaporation observed by spatially resolved photoluminescence (PL) and high excitation spectroscopy (HES).

C. Czekalla; J. Lenzner; A. Rahm; T. Nobis; M. Grundmann

2007-01-01

28

A zinc oxide microwire laser  

NASA Astrophysics Data System (ADS)

In this paper, we report stimulated emission from a zinc oxide (ZnO) microcrystal grown by carbothermal evaporation observed by spatially resolved photoluminescence (PL) and high excitation spectroscopy (HES).

Czekalla, C.; Lenzner, J.; Rahm, A.; Nobis, T.; Grundmann, M.

2007-05-01

29

Zinc oxide varistors and/or resistors  

DOEpatents

Varistors and/or resistors that includes doped zinc oxide gel microspheres. The doped zinc oxide gel microspheres preferably have from about 60 to about 95% by weight zinc oxide and from about 5 to about 40% by weight dopants based on the weight of the zinc oxide. The dopants are a plurality of dopants selected from silver salts, boron oxide, silicon oxide and hydrons oxides of aluminum, bismuth, cobalt, chromium, manganese, nickel, and antimony.

Arnold, Jr., Wesley D. (Oak Ridge, TN); Bond, Walter D. (Knoxville, TN); Lauf, Robert J. (Oak Ridge, TN)

1993-01-01

30

21 CFR 73.1991 - Zinc oxide.  

Code of Federal Regulations, 2013 CFR

... (a) Identity. (1) The color additive zinc oxide is a white or yellow-white amorphous powder manufactured by the French process (described as the indirect process whereby zinc metal isolated from the zinc-containing ore is vaporized and...

2013-04-01

31

Zinc Oxide Nanowires by Oxidation of Zinc Powder for Ethanol Gas Sensor Application  

Microsoft Academic Search

Zinc oxide nanowires were prepared by oxidation of zinc powder. The oxidation of zinc was performed by heating a tube of zinc powder at various duration times and temperatures. Field Emission Scanning Electron Microscopy (FE-SEM), Energy Disper- sive Spectrometry (EDS) and Transmission Electron Microscopy (TEM) were used to char- acterize the tube. It was found that the diameter of zinc

Chanchai Viriyaworasakul; Sombat Kittikunodom; Supab Choopun; Torranin Chairuangsri; Pongsri Mangkorntong; Nikorn Mangkorntong

32

21 CFR 73.2991 - Zinc oxide.  

Code of Federal Regulations, 2013 CFR

...LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2991 Zinc oxide. (a) Identity and...restrictions. Zinc oxide may be safely used in cosmetics, including cosmetics intended for use in the area of the eye, in...

2013-04-01

33

21 CFR 182.8991 - Zinc oxide.  

Code of Federal Regulations, 2013 CFR

...HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of use. This substance is generally...

2013-04-01

34

21 CFR 582.5991 - Zinc oxide.  

Code of Federal Regulations, 2013 CFR

...AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of...

2013-04-01

35

Field emission from zinc oxide nanopins  

Microsoft Academic Search

Nanostructural zinc oxide pins have been fabricated by vapor transport on copper-coated silicon wafer. The nanopins are composed of hexagonal wurtzite-phase zinc oxide with single crystal quality. The growth process includes two steps: (1) growth of a micron-sized zinc oxide dot on the substrate and (2) growth of a sharp tip from the zinc oxide dot. The field emission of

C. X. Xu; X. W. Sun

2003-01-01

36

Work function determination of zinc oxide films  

Microsoft Academic Search

Zinc oxide-silicon heterojunctions were fabricated using both n and p-type silicon. The zinc oxide films were deposited by magnetron sputtering process at various substrate temperatures to form these devices. The electrical properties of these devices were measured and the work function of the zinc oxide was evaluated

K. B. Sundaram; Ashamin Khan

1996-01-01

37

Zinc oxide multilayers for solar collector coatings  

Microsoft Academic Search

A solar selective coating has been fabricated by capping black zinc oxide with a transparent zinc oxide heat mirror film. Deposition onto glass substrates was accomplished by reactive bias sputtering. The zinc oxide multilayer structure had a solar absorptance of 0.90 and an IR emittance of 0.26. Suggestions are made for significant improvement of solar selective performance.

M. J. Brett; R. R. Parsons; H. P. Baltes

1986-01-01

38

Oxide Solar Cells Fabricated Using Zinc Oxide and Plasma-Oxidized Cuprous Oxide  

NASA Astrophysics Data System (ADS)

Oxide heterojunction solar cells composed of an n-type Al-doped ZnO (AZO) thin film on the surfaces of p-type Cu2O films were fabricated. The Cu2O films of about 0.34 to 1.67 ?m thickness were grown by partial oxidation of a Cu sheet using microwave plasma. The AZO film of 400 nm thickness was deposited by magnetron sputtering. Energy conversion efficiencies of 0.12 to 0.30% were obtained in AZO/Cu2O cells under AM1.5 solar illumination.

Chan, Yi-Ming; Wu, Ya-Ting; Jou, Shyankay

2012-12-01

39

Degradation of azo dye Amido black 10B in aqueous solution by Fenton oxidation process  

Microsoft Academic Search

The degradation of an azo dye Amido black 10B in aqueous solution by Fenton oxidation process has been investigated. The effects of different reaction parameters such as initial pH, the initial hydrogen peroxide concentration ([H2O2]0), the initial ferrous concentration ([Fe2+]0), the initial Amido black 10B concentration ([dye]0) and the temperature on the oxidative degradation of Amido black 10B have been

Jian-Hui Sun; Sheng-Peng Sun; Guo-Liang Wang; Li-Ping Qiao

2007-01-01

40

Effect of Zinc, Zinc Oxide and Zinc Borate on the Flammability of Polycarbonate  

Microsoft Academic Search

Polycarbonate was blended with zinc, zinc borate (2ZnO·3B2O 3·3.5H2O) and zinc oxide. Blends made of zinc\\/polycarbonate and especially zinc borate\\/polycarbonate show major improvement in oxygen index values. Ohio State University (OSU) heat release studies show reduction in heat release only for zinc borate\\/polycarbonate blends compared to virgin polycarbonate. No improvement in smoke suppression was observed from NBS Smoke Chamber studies

Ramazan Benrashid; Gordon L. Nelson; Donald J. Ferm; Leland W. Chew

1995-01-01

41

Influence of grain size on AZO ceramic synthesis  

NASA Astrophysics Data System (ADS)

Aluminum doped zinc oxide (AZO) is a transparent conducting oxide (TCO) with oxygen vacancy mediated carrier density and mobility. Due to low oxygen self-diffusivity, the influence of thermal reducing treatments is strongly dependent on grain size. Electrical resistivity and Seebeck coefficient measurements suggest that mobility changes prevail to increase conductivity by reducing atmosphere anneal.

Vera, C.; Maioco, S.; Rajchenberg, N.; Aragón, R.

2013-03-01

42

The effects of oxygen vacancies in space stable aluminum-doped zinc oxide thin films  

NASA Astrophysics Data System (ADS)

Polycrystalline ZnO:Al (AZO) thin films are routinely deposited by RF magnetron sputtering. The figures of merit, resistivity (rho) and transmittance (T), of AZO films deposited using an oxide target are heavily dependent upon residual water vapor within the growth chamber Zinc oxide is an inherently n-type material in which the oxygen vacancy (VO) is the main donor defect. The substitution of Al onto the Zn sublattice has been shown to enhance the conductivity of AZO; however, this work shows that VO donors play a critical role in the degenerate doping of AZO. Additional oxygen supplied by residual water vapor during growth was found to produce transparent (T>80%) and resistive (rho˜14 O cm) films due to the reduced density of donor species through the filling of VO and the oxidation of Al. Films grown without the presence of additional oxygen exhibited average resistivities on the order of 3x10-3 O cm and optical transmittance values of -60%. An increased density of VO and active Al 3+ donors contribute to the reduced resistivity, whereas metallic Al segregated at grain boundaries negatively affected the film optical properties. Post-deposition anneals in N2 were found to generate additional VO and incorporate of Al into the ZnO lattice. X-ray photoelectron spectroscopy (XPS) measurements of the asymmetric O 1s core level were used to determine the degree of oxygen deficiency within the layers as a function of residual water vapor and post-growth annealing.

Lennon, Craig M.

43

Zinc hydroxide sulphate and its transformation to crystalline zinc oxide.  

PubMed

The thermal transformation of zinc hydroxide sulphate hydrate to zinc oxide has been examined using synchrotron X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and surface area measurements. By collecting X-ray diffraction data in situ, we found that the dehydration of zinc hydroxide sulphate pentahydrate proceeded in discrete steps to form anhydrous zinc hydroxide sulphate. This compound then decomposed to a mixture of zinc oxide and a compound tentatively identified as Zn3(OH)2(SO4)2 at ?235 °C. At ?360 °C, the final dehydroxylation occurred with the formation of zinc oxy-sulphate, Zn3O(SO4)2, which then decomposed to ZnO at about ?800 °C. Interruption of the dehydration process can be used to synthesize the intermediate compounds. PMID:23963063

Moezzi, Amir; Cortie, Michael B; McDonagh, Andrew M

2013-09-24

44

Synthesis of zinc oxide by zinc–air system  

Microsoft Academic Search

An economical and environment friendly zinc–air system route is used for the synthesis of zinc oxide (ZnO) on a zinc (Zn) plate in room temperature. A Zn plate and a single air-cathode are used as the anode and cathode, respectively. It is found that the growth of ZnO increases with increasing electrolyte solution concentration until an optimum concentration is reached.

C. K. Yap; W. C. Tan; S. S. Alias; A. A. Mohamad

2009-01-01

45

Zinc oxide as an ozone sensor  

Microsoft Academic Search

This work presents a study of intrinsic zinc oxide thin film as ozone sensor based on the ultraviolet (UV) photoreduction and subsequent ozone re oxidation of zinc oxide as a fully reversible process performed at room temperature. The films analyzed were produced by spray pyrolysis, dc and rf magnetron sputtering. The dc resistivity of the films produced by rf magnetron

R. Martins; E. Fortunato; P. Nunes; I. Ferreira; A. Marques; M. Bender; N. Katsarakis; V. Cimalla; G. Kiriakidis

2004-01-01

46

Comparative toxicity of a zinc salt, zinc powder and zinc oxide to Eisenia fetida, Enchytraeus albidus and Folsomia candida  

Microsoft Academic Search

The pore water zinc concentration and the calcium chloride extracted zinc fraction are higher in the soils spiked with a zinc salt (ZnCl2) compared to soils spiked with zinc oxide or zinc powder. Based on total zinc concentrations in the soil, the acute toxicity of zinc salt to the compost worm Eisenia fetida, the potworm Enchytraeus albidus and the springtail

Koen Lock; Colin R. Janssen

2003-01-01

47

Electronic Structure of Zinc Oxide and Related Crystals.  

National Technical Information Service (NTIS)

The aim of this investigati on is the elucidation of the electronic energy band structure of zinc oxide and related wurtzite-type crystals, including alloys of zinc oxide and zinc sulfide; zinc sulfide; zinc selenide; and zinc telluride. The principal fea...

F. Herman

1966-01-01

48

Influence of RF power on magnetron sputtered AZO films  

NASA Astrophysics Data System (ADS)

Al-doped Zinc Oxide (AZO) transparent conducting films are prepared on glass substrate by RF magnetron sputtering under different RF power with a 3 inch diameter target of 2 wt% Al2O3 in zinc oxide. The effect of RF power on the structural, optical and electrical properties of AZO films was investigated by X-ray Diffraction (XRD), Hall measurement and UV-Visible spectrophotometry. The XRD data indicates a preferential c-axis orientation for all the films. All films exhibit high transmittance (<90%) in visible region. Films deposited at 60 W power exhibit lowest resistivity of 5.7×10-4?cm. Such low-resistivity and high-transmittance AZO films when prepared using low RF power at room temperature could find important applications in flexible electronics.

Agarwal, Mohit; Modi, Pankaj; Dusane, R. O.

2013-02-01

49

Electronic structure of spinel oxides: zinc aluminate and zinc gallate  

NASA Astrophysics Data System (ADS)

The electronic structure of zinc aluminate (ZnAl2O4) and that of zinc gallate (ZnGa2O4) were studied by the self-consistent tight-binding linearized muffin-tin orbital method with the atomic sphere approximation. The calculated results predict these zinc-based spinel oxides to be direct-gap materials. The direct gap at icons/Journals/Common/Gamma" ALT="Gamma" ALIGN="TOP"/> is found to be 4.11 eV for ZnAl2O4 and 2.79 eV for ZnGa2O4. With reference to the calculated band gap of 5.36 eV for MgAl2O4, the systematic decrease in the gap is attributed to the presence of 3d orbitals of Zn and Ga and the associated p-d hybridization in the upper valence band of zinc aluminate and gallate. Comparison of the contour maps of the electron localization function of ZnAl2O4 and ZnGa2O4 with that of MgAl2O4 clearly shows the bonding to be less ionic in the zinc-based spinel oxides. Finally, the calculations yield a smaller electron effective mass for zinc gallate as compared to that for zinc aluminate, suggesting a higher mobility of electrons in gallate.

Sampath, Suresh K.; Kanhere, D. G.; Pandey, Ravindra

1999-05-01

50

Zinc phosphide-zinc oxide heterojunction solar cells  

Microsoft Academic Search

Zinc phosphide-zinc oxide heterojunction solar cells have been prepared by sputter-depositing ZnO onto a Zn3P2 substrate. An active-area conversion efficiency of 2% has been obtained. In the absence of shunts and by reducing the series resistance of the device, an efficiency of 5% is achievable. The experimental results are discussed in terms of an interface recombination model. It is indicated

P. S. Nayar; A. Catalano

1981-01-01

51

Ferromagnetism of nanostructured zinc oxide films  

NASA Astrophysics Data System (ADS)

The paper presents a review of the causes of the occurrence of ferromagnetic properties in zinc oxide. It is shown that ferromagnetism only occurs in polycrystals at a fairly high density of grain boundaries. The critical grain size is about 20 nm for pure ZnO and over 1000 nm for zinc oxide doped with manganese. The solubility of manganese and cobalt in zinc oxide increases considerably with diminishing grain size. Even at the critical grain size, the ferromagnetic properties depend significantly on the film texture and the structure of intercrystalline amorphous layers.

Straumal, B. B.; Mazilkin, A. A.; Protasova, S. G.; Straumal, P. B.; Myatiev, A. A.; Schütz, G.; Goering, E.; Baretzky, B.

2012-12-01

52

The growth of zinc oxide nanocrystals on the zinc oxide thin film by chemical bath deposition  

Microsoft Academic Search

In the paper the low temperature deposition of zinc oxide called Chemical Bath Deposition (CBD) will be described. Zinc oxide nanocrystals grow on the thin layer of ZnO. In our investigation the thin film of ZnO was deposited using spin coating, on the glass substrate covered with thin film of Indium Tin Oxide (ITO). The goal of our research is

Michal Byrczek; Miroslaw Malewicz; Helena Teterycz

2009-01-01

53

Optical and electrical properties of zinc oxide\\/indium\\/zinc oxide multilayer structures  

Microsoft Academic Search

Zinc oxide\\/indium\\/zinc oxide multilayer structures have been obtained on glass substrates by magnetron sputtering. The effects of indium thickness on optical and electrical properties of the multilayer structures are investigated. Compared to a single zinc oxide layer, the carrier concentration increases from 8×1018cm?3 to 1.8×1020cm?3 and Hall mobility decreases from 10cm2\\/vs to 2cm2\\/vs for the multilayer structure at 8nm of

Le-Chun Ji; Lei Huang; Yang Liu; Yi-Qun Xie; Feng Liu; Ai-Yun Liu; Wang-Zhou Shi

2011-01-01

54

Ferromagnetism of zinc oxide nanograined films  

NASA Astrophysics Data System (ADS)

The reasons for the appearance of ferromagnetic properties of zinc oxide have been reviewed. It has been shown that ferromagnetism appears only in polycrystals at a quite high density of grain boundaries. The critical size of grains is about 20 nm for pure ZnO and more than 40 ?m for iron-doped zinc oxide. The solubility of manganese and cobalt in zinc oxide increases significantly with a decrease in the size of grains. The dependences of the saturation magnetization on the concentrations of cobalt, manganese, and ion are nonmonotonic. Even if the size of grains is below the critical value, the ferromagnetic properties of zinc oxide depend significantly on the texture of films and the structure of amorphous intercrystallite layers.

Straumal, B. B.; Protasova, S. G.; Mazilkin, A. A.; Schütz, G.; Goering, E.; Baretzky, B.; Straumal, P. B.

2013-05-01

55

Highly unsaturated fatty acid might act as an antioxidant in emulsion system oxidized by azo compound.  

PubMed

Now it is recognized that DHA is oxidatively stable fatty acid compared with linoleic acid (LA) in emulsified system, although DHA is oxidatively unstable in a bulk system. In fact, an emulsified mixture of DHA and LA behaves as in a bulk system, namely the oxidative stability of DHA becomes lower than that of LA. Therefore, in this study, tridocosahexaenoate (DDD) and glycerol trilinoleate (LLL) were separately emulsified using TritonX-100 as an emulsifier and DDD emulsion was mixed with the oxidizing LLL emulsion using a water-soluble radical initiator, 2,2'-azobis(2-aminopropane) dihydrochloride. As a result, DHA suppressed the oxidation of LA, while DHA was not significantly oxidized. This suppression ability was examined using glycerol trieicosapentaenoate, glycerol trilinolenate, or glycerol trioleate instead of DDD and it was found that this activity was increased with the increasing number of double bonds in the structure. Furthermore, the same type of experiment was carried out using a lipid-soluble radical initiator, 2,2'-azobisisobutyronitrile and the similar result was obtained. These results indicated that a highly polyunsaturated fatty acid might act as an antioxidant in an emulsion system oxidized by an azo compound. PMID:21099140

Gotoh, Naohiro; Noguchi, Yosuke; Ishihara, Akiko; Yamaguchi, Kaita; Mizobe, Hoyo; Nagai, Toshiharu; Otake, Ikuko; Ichioka, Kenji; Wada, Shun

2010-01-01

56

Second harmonic generation in zinc oxide nanorods  

Microsoft Academic Search

Second-order optical nonlinearities of zinc oxide (ZnO) nanorods grown on quartz substrate were determined by optical second\\u000a harmonic generation (SHG) measurements at 1064 nm fundamental wavelength. The average length of the zinc oxide nanorods ranged\\u000a from 50 nm to 700 nm. By employing the Maker fringes technique, we obtained the second-order nonlinear optical coefficients\\u000a d333 and d311. Their magnitudes and ratio are compared

S. W. Chan; R. Barille; J. M. Nunzi; K. H. Tam; Y. H. Leung; W. K. Chan; A. B. Djuriši?

2006-01-01

57

Second harmonic generation in zinc oxide nanorods  

Microsoft Academic Search

Second-order optical nonlinearities of zinc oxide (ZnO) nanorods grown on quartz substrate were determined by optical second harmonic generation (SHG) measurements at 1064 nm fundamental wavelength. The average length of the zinc oxide nanorods ranged from 50 nm to 700 nm. By employing the Maker fringes technique, we obtained the second-order nonlinear optical coefficients d333 and d311. Their magnitudes and

S. W. Chan; R. Barille; J. M. Nunzi; K. H. Tam; Y. H. Leung; W. K. Chan; A. B. Djurisic

2006-01-01

58

Oxidation of commercial reactive azo dye aqueous solutions by the photo-Fenton and Fenton-like processes  

Microsoft Academic Search

This paper evaluates the degradation of two azo reactive dyes, C.I. Reactive Yellow 84 (RY84) and C.I. Reactive Red 120 (RR120) by photo-Fenton and Fenton-like oxidation. All experiments were performed on a laboratory scale set-up. The effects of different reaction parameters such as initial pH, contact time, effect of light and hydrogen peroxide concentrations on the oxidation of the dye

Mariana Neamtu; Ayfer Yediler; Ilie Siminiceanu; Antonius Kettrup

2003-01-01

59

Wet oxidation of an azo dye: Lumped kinetics in batch and mixed flow reactors  

SciTech Connect

Oxidation of a dilute aqueous solution of a model azo dye pollutant (Orange II) was studied in batch and continuous well-mixed (CSTR) reactors. Both reactors operate at 200--250 C, and total pressures up to 50 bar and at oxygen partial pressure from 10 to 30 bar. The model pollutant concentrations were in a range between 100 and 1,000 mg/L, which may be found in industrial wastewaters. The dye oxidation undergoes parallel-consecutive reaction pathways, in which it first decomposes thermally and oxidatively to aromatic intermediates and via organic acids to the final product carbon dioxide. To develop a kinetic equation capable of predicting organic carbon reduction, all organic species present in solution were lumped by total organic carbon (TOC). The lumped oxidation rate in batch reactor exhibited second-order behavior, whereas in the CSTR is was found linearly proportional to its TOC concentration. The lump behavior in batch reactor was dominated by the refractory low molecular mass aliphatic acids formed during the oxidation.

Donlagic, J.; Levec, J.

1999-12-01

60

Peroxidase-catalyzed oxidation of azo dyes: mechanism of disperse Yellow 3 degradation.  

PubMed

Disperse Yellow 3 [2-(4'-acetamidophenylazo)-4-methylphenol] (DY3) (I) is an important yellow dye used in industry and is also a carcinogen. Earlier we demonstrated that lignin-degrading cultures of white-rot basidiomycete Phanerochaete chrysosporium degrade DY3 to CO2. In this report, we have examined the degradation of DY3 and its naphthol analog, 1-(4'-acetamidophenylazo)-2-naphthol (NDY3) (II) by lignin peroxidase, horseradish peroxidase, and Mn(III)-malonate complex (a manganese peroxidase mimic). Lignin and manganese peroxidases are two extracellular peroxidase produced by ligninolytic cultures of P. chrysosporium and are involved in the degradation of lignin and various other environmental pollutants by this fungus. DY3 oxidation by peroxidases yields 4-methyl-1,2-benzoquinone (III), acetanilide (IV), and a dimer of DY3 (V) as products. NDY3 oxidation yields acetanilide (IV) and 1,2-naphthoquinone (VI). In deuterium incorporation experiments with DY3, 55-67% incorporation of deuterium from dioxane-d8 into acetanilide (IV) is observed. However, when D2O is the donor, deuterium is not incorporated into acetanilide (IV). Based on these results, a mechanism for azo dye degradation is proposed. The H2O2-oxidized forms of a peroxidase oxidize the phenolic ring of DY3, or its analogs, by two electrons to produce a carbonium ion, which is located on the carbon bearing the azo linkage. Water attacks the carbonium ion, producing an unstable intermediate which breaks down to generate 1,2-naphthoquinone (VI) or 4-methyl-1,2-benzoquinone (III) and 4-acetamido-phenyldiazene. O2, H2O2-oxidized peroxidase, or a metal ion, oxidize the phenyldiazene by one electron to produce a phenyldiazene radical, which cleaves homolytically to generate 4-acetamidophenyl radical and molecular nitrogen. The 4-acetamidophenyl radical then abstracts a hydrogen radical from the surroundings to produce acetanilide (IV). DY3 degradation by whole cultures of P. chrysosporium yields acetanilide as the major product. This suggests that lignin peroxidase and manganese peroxidase are involved in the in vivo metabolism of DY3 by P. chrysosporium. PMID:8031141

Spadaro, J T; Renganathan, V

1994-07-01

61

Effect of Zinc and Zinc Borate on Fire Properties of Modified Polyphenylene Oxide  

Microsoft Academic Search

Modified polyphenylene oxide resin (m-PPO) (virgin) and m-PPO flame retarded with triaryl phosphate (FR m-PPO) were blended with zinc borate, zinc, and zinc\\/zinc borate. Both virgin and FR m-PPO containing zinc borate showed a marked reduction in smoke production (flaming and non- flaming-NBS Smoke Chamber). In FR m-PPO a reduction in oxygen index values was seen for zinc borate, except

R. Benrashid; G. L. Nelson; Donald J. Ferm

1993-01-01

62

Facile Cu(I)-catalyzed oxidative coupling of anilines to azo compounds and hydrazines with diaziridinone under mild conditions.  

PubMed

A mild and highly efficient Cu(I)-catalyzed oxidative coupling of anilines is described. Various primary and secondary anilines can be efficiently coupled under mild conditions to the corresponding azo compounds and hydrazines in high yields. This method provides a direct and practical access to these compounds and is also amenable to gram scale with no special precautions to exclude air or moisture. PMID:23545123

Zhu, Yingguang; Shi, Yian

2013-04-01

63

Oxidation of Levafix CA reactive azo-dyes in industrial wastewater of textile dyeing by electro-generated Fenton's reagent  

Microsoft Academic Search

The indirect electrochemical removal of pollutants from effluents has become an attractive method in recent years. Removal (decolorization and mineralization) of Levafix Blue CA and Levafix Red CA reactive azo-dyes from aqueous media by electro-generated Fenton's reagent (Fe2+\\/H2O2) using a reticulated vitreous carbon cathode and a platinum gauze anode was optimized. Progress of oxidation (decolorization and mineralization) of the investigated

Hanaa S. El-Desoky; Mohamed M. Ghoneim; Ragaa El-Sheikh; Naglaa M. Zidan

2010-01-01

64

Decolorization of disperse red 354 azo dye in water by several oxidation processes—a comparative study  

Microsoft Academic Search

The degradation of the Disperse Red 354 azo dye in water was investigated in laboratory-scale experiments, using four advanced oxidation processes (AOPs): ozonation, Fenton, UV\\/H2O2, and photo-Fenton. The photodegradation experiments were carried out in a stirred batch photoreactor equipped with an immersed low-pressure mercury lamp as UV source. Besides the conventional parameters, on acute toxicity test with a LUMIStox 300

Mariana Neamtu; Ayfer Yediler; Ilie Siminiceanu; Matei Macoveanu; Antonius Kettrup

2004-01-01

65

Effect of solvent volume on the physical properties of aluminium doped nanocrystalline zinc oxide thin films deposited using a simplified spray pyrolysis technique  

NASA Astrophysics Data System (ADS)

Aluminium doped zinc oxide (AZO) thin films were deposited by employing a low cost and simplified spray technique using a perfume atomizer from starting solutions having different volumes (10, 20, … , 50 mL) of solvent. The effect of solvent volume on the structural, electrical, optical, photoluminescence (PL) and surface morphological properties was studied. The electrical resistivity of the AZO films is remarkably influenced by the variation in the solvent volume. The X-ray diffraction profiles clearly showed that all the films have preferential orientation along the (0 0 2) plane irrespective of the solvent volume. The crystallite size was found to be in the nano range of 35-46 nm. The optical transmittance in the visible region is desirably high (>85%). The AFM images show columnar morphology with varying grain size. The PL studies revealed that the AZO film deposited from 50 mL of solvent volume has good quality with lesser defect density.

Jabena Begum, N.; Mohan, R.; Ravichandran, K.

2013-01-01

66

Photoluminescent properties of copper-doped zinc oxide nanowires  

Microsoft Academic Search

Copper-doped zinc oxide nanowires were fabricated on copper-coated silicon substrate by sintering a mixture of zinc oxide and graphite powders at high temperature. Copper functioned as a catalyst in the zinc oxide nanowire growth and was incorporated during the growth as a dopant. The size of copper-doped zinc oxide nanowires ranges from 30 to 100 nm in diameter and tens

C X Xu; X W Sun; X H Zhang; L Ke; S J Chua

2004-01-01

67

Electrochemical oxidation of an azo dye in aqueous media investigation of operational parameters and kinetics.  

PubMed

In this research two types of electrochemical reactors for the treatment of simulated wastewaters containing Direct blue 71 azo dye (DB71) were used: (1) Laboratory scale undivided electrolysis cell system (450 mL volume) with one 2 cm x 2 cm platinum plate as the anode placed in the middle of the cell and two 2 cm x 8 cm steel plates (SS-304) as cathodes placed in the sides of the cell 2 cm from the central anode. (2) Pilot scale reactor (9L volume), equipped with two 3 cm x 23 cm stainless steel plates as anode and cathode, with distance of 3 cm apart. The influence of supporting electrolyte, applied voltage and pH were studied. The UV-vis spectra of samples during the electrochemical oxidation showed the rapid decolorization of the dye solution. During the process, the COD and current were measured in order to evaluate the degree of mineralization, energy consumption, current and anode efficiencies. The optimum supporting electrolyte and applied voltage were NaCl (5 g L(-1)) and 15 V. Using the lab scale reactor resulted in complete decolorization and mineralization of the dye solutions after ca. 90 and 120 min, respectively. Similar results were obtained using the pilot plant reactor under the same conditions. The good fit of the data to pseudo-first-order kinetics for COD removal at all applied voltages (except 20 V) was taken as proof of the involvement of indirect oxidation pathways in the process. PMID:19345003

Parsa, J Basiri; Rezaei, M; Soleymani, A R

2009-03-09

68

A Zinc Oxide modified Porous Silicon humidity sensor  

Microsoft Academic Search

In this paper, a relative humidity sensor based on zinc oxide modified porous silicon was discussed. The porous silicon was prepared by electrochemical etching process first. Then the sol-gel precursor of Zinc Oxide was applied to the PS substrates and annealed at 450 degC. By this technique, it is possible to obtain a uniform zinc oxide film on the porous

Tao Jiang; Xiaofeng Zhou; Jian Zhang; Yanling Shi; Tianxing Luo

2006-01-01

69

21 CFR 73.1991 - Zinc oxide.  

Code of Federal Regulations, 2010 CFR

...impurities other than those named to the extent that such impurities may be avoided by good manufacturing practice: Zinc oxide (as ZnO), not less than 99 percent. Loss on ignition at 800 °C, not more than 1 percent. Cadmium (as Cd), not more...

2010-04-01

70

21 CFR 73.1991 - Zinc oxide.  

Code of Federal Regulations, 2010 CFR

...impurities other than those named to the extent that such impurities may be avoided by good manufacturing practice: Zinc oxide (as ZnO), not less than 99 percent. Loss on ignition at 800 °C, not more than 1 percent. Cadmium (as Cd), not more...

2009-04-01

71

Zinc oxide varistors for lightning arrester service  

Microsoft Academic Search

The application of zinc oxide varistors to high power surge arresters for electrical transmission lines is considered, with particular attention to the special measurement problems posed by the application and by the unique properties of these varistors. The development of ZnO varistors and the present theory of ZnO varistor action are discussed. The need for further elaboration of the theory

R. I. Scace

1980-01-01

72

Zinc Oxide Varistors for Lightning Arrester Service.  

National Technical Information Service (NTIS)

The application of zinc oxide (ZnO) varistors to high-power surge arresters for electrical transmission lines is considered, with particular attention to the special measurement problems posed by the application and by the unique properties of these varis...

R. I. Scace

1979-01-01

73

Effect of zinc oxide on yttria doped ceria  

Microsoft Academic Search

Solid electrolyte ceramics consisted of ceria, yttria and zinc oxide has been synthesized through solid state reaction. With the zinc oxide content over 0.4mol.%, this material is able to achieve a relative density of 96% at 1375°C, about 200°C lower than that without zinc oxide. The result of XRD reveals that the lattice parameter increased with the concentration of zinc

Ling Gao; Ming Zhou; Yifeng Zheng; Haitao Gu; Han Chen; Lucun Guo

2010-01-01

74

Low-temperature solution-processed metal oxide buffer layers fulfilling large area production requirements  

NASA Astrophysics Data System (ADS)

This paper is a review of our previous work on the field of low temperature, solution processed metal oxide buffer layers published in various journals. Our work focuses on zinc oxide (ZnO) and aluminum-doped zinc oxide (AZO) as n-type and molybdenum oxide (MoO3) as p-type solution processed buffer layer. In addition to that, we investigate the surface modification of AZO using phosphonic acid-anchored aliphatic and fullerene self assembled monolayers (SAMs).

Stubhan, T.; Litzov, I.; Li, Ning; Wang, H. Q.; Krantz, J.; Machui, F.; Steidl, M.; Oh, H.; Matt, G. J.; Brabec, C. J.

2012-09-01

75

Percutaneous Absorption of Zinc from Zinc Oxide Applied Topically to Intact Skin in Man  

Microsoft Academic Search

The penetration of zinc through normal skin treated with a zinc oxide (25%) medicated occlusive dressing was studied.The mean release rate of zinc to the skin was 5 ?g\\/cm2\\/h. After 48 h of treatment suction blisters were raised by the« Kiistala method. The zinc concentration of the epidermis blister fluid and dermis was increased beneath the zinc dressing compared to

Magnus S. Ågren

1990-01-01

76

Oxidative degradation of azo dyes by manganese peroxidase under optimized conditions.  

PubMed

The application of enzyme-based systems in waste treatment is unusual, given that many drawbacks are derived from their use, including low efficiency, high costs and easy deactivation of the enzyme. The goal of this study is the development of a degradation system based on the use of the ligninolytic enzyme manganese peroxidase (MnP) for the degradation of azo dyes. The experimental work also includes the optimization of the process, with the objective of determining the influence of specific physicochemical factors, such as organic acids, H(2)O(2) addition, Mn(2+) concentration, pH, temperature, enzyme activity and dye concentration. A nearly total decolorization was possible at very low reaction times (10 min) and at high dye concentration (up to 1500 mg L(-)(1)). A specific oxidation capacity as high as 10 mg dye degraded per unit of MnP consumed was attained for a decolorization higher than 90%. Among all, the main factor affecting process efficiency was the strategy of H(2)O(2) addition. The continuous addition at a controlled flow permitted the progressive participation of H(2)O(2) in the catalytic cycle through a suitable regeneration of the oxidized form of the enzyme, which enhanced both the extent and the rate of decolorization. It was also found that, in this particular case, the presence of a chelating organic acid (e.g., malonic) was not required for an effective operation. Probably, Mn(3+) was chelated by the dye itself. The simplicity and high efficiency of the process open an interesting possibility of using of MnP for solving other environmental problems. PMID:12675567

Mielgo, I; López, C; Moreira, M T; Feijoo, G; Lema, J M

77

Anodic Oxidation of Zinc Phosphide  

Microsoft Academic Search

Initial stages of a native oxidation on Zn3P2 by anodization have been investigated for the first time using 3% tartaric acid\\/propylene glycol electrolyte. A constant-current anodization is found to be superior to a constant-voltage anodization because of the rapid growth of the initial stage in the constant-voltage mode in view of controlling thin oxide layers. The surface composition of anodized

Toshikazu Suda; Yoshitada Murata; Shoichi Kurita

1986-01-01

78

Field emission from gallium-doped zinc oxide nanofiber array  

Microsoft Academic Search

Gallium-doped nanostructural zinc oxide fibers have been fabricated by vapor-phase transport method of heating the mixture of zinc oxide, gallium oxide, and graphite powders in air. The zinc oxide fibers grew along [002] direction, forming a vertically aligned array that is predominantly perpendicular to the substrate surface. With a gallium doping concentration of 0.73 at. %, the corresponding carrier concentration

C. X. Xu; X. W. Sun; B. J. Chen

2004-01-01

79

Toxicity of zinc oxide nanoparticles through oral route.  

PubMed

This experiment was aimed to determine the significance of dose by comparing acute oral toxicological potential of nano-sized zinc oxide (20 nm) with its micro-sized zinc oxide. Sprague Dawley rats, 8 to 9 weeks old, were administered with 5, 50, 300, 1000 and 2000 mg/kg body weight (b.w.) of nano- and micro-sized zinc oxide suspended in distilled water once through oral gavage. The effects of the micro- and nano-sized zinc oxide on biochemical and hematological parameters were analyzed on day 14 of administration. The organs were collected for histopathology. Interestingly, inverse dose-dependent increase was noted in aspartate aminotransferase, alanine aminotransferase serum levels of nano-size zinc oxide groups when compared with their micro-sized zinc oxide. Clotting time was effected in all the male groups of nano-size zinc oxide, except in 1000 mg/kg b.w. The incidences of microscopic lesions in liver, pancreas, heart and stomach were higher in lower doses of nano-size zinc oxide compared to higher dose. However, the incidences of above lesions were higher in rats treated with a high dose of micro-sized zinc oxide. We conclude that nano-size zinc oxide exhibited toxicity at lower doses, thus alarming future nanotoxicology research needs to be focused on importance of dose metrics rather following the conventional methods while conducting in vivo experiments. PMID:22033421

Pasupuleti, Surekha; Alapati, Srinivas; Ganapathy, Selvam; Anumolu, Goparaju; Pully, Neelakanta Reddy; Prakhya, Balakrishna Murthy

2011-10-27

80

Zinc oxide nanostructures: growth, properties and applications  

Microsoft Academic Search

Zinc oxide is a unique material that exhibits semiconducting and piezoelectric dual properties. Using a solid–vapour phase thermal sublimation technique, nanocombs, nanorings, nanohelixes\\/nanosprings, nanobelts, nanowires and nanocages of ZnO have been synthesized under specific growth conditions. These unique nanostructures unambiguously demonstrate that ZnO probably has the richest family of nanostructures among all materials, both in structures and in properties. The

Zhong Lin Wang

2004-01-01

81

Zinc oxide varistors for lightning arrester service  

NASA Astrophysics Data System (ADS)

The application of zinc oxide varistors to high power surge arresters for electrical transmission lines is considered, with particular attention to the special measurement problems posed by the application and by the unique properties of these varistors. The development of ZnO varistors and the present theory of ZnO varistor action are discussed. The need for further elaboration of the theory is considered.

Scace, R. I.

1980-01-01

82

Anodic Oxidation of Zinc Phosphide  

NASA Astrophysics Data System (ADS)

Initial stages of a native oxidation on Zn3P2 by anodization have been investigated for the first time using 3% tartaric acid/propylene glycol electrolyte. A constant-current anodization is found to be superior to a constant-voltage anodization because of the rapid growth of the initial stage in the constant-voltage mode in view of controlling thin oxide layers. The surface composition of anodized Zn3P2 was examined by AES and XPS. The oxide layer was identified as a mixture of ZnO, P2O5, and P2O3: the increased [P2O5+P2O3]/[ZnO] ratio of ˜ 1.3 was obtained at acidic and basic pH values, whereas the composition ratio was ˜ 0.2 near a neutral pH value as a result of selective dissolution of either ZnO or POx.

Suda, Toshikazu; Murata, Yoshitada; Kurita, Shoichi

1986-02-01

83

Process for preparing zinc oxide-based sorbents  

DOEpatents

The disclosure relates to zinc oxide-based sorbents, and processes for preparing and using them. The sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents comprise an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, comprising a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

Gangwal, Santosh Kumar (Cary, NC); Turk, Brian Scott (Durham, NC); Gupta, Raghubir Prasad (Durham, NC)

2011-06-07

84

``Magic'' Vicinal Zinc Oxide Surfaces  

NASA Astrophysics Data System (ADS)

The structure of (0001) oriented ZnO single crystal surfaces is investigated by scanning tunneling microscopy. Depending on the preparation conditions, faceting of the crystals into large areas of {101¯4} surface orientation occurs. This restructuring of the surface is shown to be a consequence of dipole compensation and charge neutralization. A new stabilization mechanism of polar oxide surfaces is found which is based on the formation of vicinal surfaces with special electronic and structural properties.

Zheng, Hao; Gruyters, Markus; Pehlke, Eckhard; Berndt, Richard

2013-08-01

85

Copper, silver, gold and zinc, cadmium, mercury oxides and hydroxides  

SciTech Connect

This book provides a compilation of solubility data published up to 1984, including evaluations of the data. Data are presented on the following: copper (I) oxide; copper (II) oxide and hydroxide; silver (I) oxide; silver (II) oxide; gold (III) hydroxide; zinc oxide and hydroxide; cadmium oxide and hydroxide; and mercury (II) oxide.

Dirkse, T.P.

1986-01-01

86

Thermally oxidized zinc oxide nanowires for use as chemical sensors  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) mat-based conductometric devices were fabricated using a thermal oxidation technique. A metallic zinc layer was deposited on the alumina transducer and then oxidized in a controlled atmosphere, in order to obtain ZnO nanostructures. Two different batches of sensors have been prepared, and their sensing performances have been evaluated towards oxidizing and reducing gases. Functional measurements showed very good sensing performances towards ethanol and acetone at 500?° C, and NO2 at 200?° C, indirectly confirming the n-type behaviour of the material. The influence of the humidity on the response has been explored. In practical conditions the interference of humidity is very small, and could be neglected in many applications. Simultaneous measurements on different devices from the same batch confirm the high reproducibility of the response within the batch.

Zappa, D.; Comini, E.; Sberveglieri, G.

2013-11-01

87

Thermally oxidized zinc oxide nanowires for use as chemical sensors.  

PubMed

Zinc oxide (ZnO) mat-based conductometric devices were fabricated using a thermal oxidation technique. A metallic zinc layer was deposited on the alumina transducer and then oxidized in a controlled atmosphere, in order to obtain ZnO nanostructures. Two different batches of sensors have been prepared, and their sensing performances have been evaluated towards oxidizing and reducing gases. Functional measurements showed very good sensing performances towards ethanol and acetone at 500?° C, and NO2 at 200?° C, indirectly confirming the n-type behaviour of the material. The influence of the humidity on the response has been explored. In practical conditions the interference of humidity is very small, and could be neglected in many applications. Simultaneous measurements on different devices from the same batch confirm the high reproducibility of the response within the batch. PMID:24113169

Zappa, D; Comini, E; Sberveglieri, G

2013-10-10

88

Zinc oxide thin-film random lasers on silicon substrate  

Microsoft Academic Search

Room-temperature ultraviolet lasing is demonstrated in mirrorless zinc oxide thin-film waveguides on (100) silicon substrate. Laser cavities, due to closed-loop optical scattering from the lateral facets of the irregular zinc oxide grains, are generated through the post-growth annealing of high-crystal-quality zinc oxide thin films obtained from the filtered cathodic vacuum arc technique. It is found that the lasing wavelength and

S. F. Yu; Clement Yuen; S. P. Lau; H. W. Lee

2004-01-01

89

Study of humidity properties of Zinc Oxide modified Porous Silicon  

Microsoft Academic Search

In this paper, we discussed the humidity sensing behavior of Zinc Oxide modified porous silicon (ZnO\\/PS) composite structure. The porous silicon substrates were prepared by the electrochemical etching process first. Then, by sol-gel technique, it is possible to obtain a uniform Zinc Oxide films on the porous silicon substrates. The electrical conductivities of the porous silicon and Zinc Oxide modified

Tao Jiang; Xiaofeng Zhou; Jian Zhang; Jianzhong Zhu; Xinxin Li; Tie Li

2006-01-01

90

Degradation of Azo Dyes by Trametes villosa Laccase over Long Periods of Oxidative Conditions  

Microsoft Academic Search

The chemical structure of dyes is comprised of a conjugated system of double bonds and aromatic rings. The major classes of dyes have antroquinoid, indigoid, and azo aromatic struc- tures. All of these structures allow strong -* transitions in the UV-visible (UV-Vis) area, with high extinction coefficients that allow us to consider these structures dye chromophores. Of all of these

Andrea Zille; Barbara Gornacka; Astrid Rehorek; Artur Cavaco-Paulo

2005-01-01

91

Influence of growth temperature on electrical, optical, and plasmonic properties of aluminum:zinc oxide films grown by radio frequency magnetron sputtering  

NASA Astrophysics Data System (ADS)

We have investigated the responsible mechanism for the observation of metallic conductivity at room temperature and metal-semiconductor transition (MST) at lower temperatures for aluminum-doped zinc oxide (AZO) films. AZO films were grown on glass substrates by radio-frequency magnetron sputtering with varying substrate temperatures (Ts). The films were found to be crystalline with the electrical resistivity close to 1.1 × 10-3 ? cm and transmittance more than 85% in the visible region. The saturated optical band gap of 3.76 eV was observed for the sample grown at Ts of 400 °C, however, a slight decrease in the bandgap was noticed above 400 °C, which can be explained by Burstein-Moss effect. Temperature dependent resistivity measurements of these highly conducting and transparent films showed a MST at ~110 K. The observed metal-like and metal-semiconductor transitions are explained by taking into account the Mott phase transition and localization effects due to defects. All AZO films demonstrate crossover in permittivity from positive to negative and low loss in the near-infrared region, illustrating its applications for plasmonic metamaterials, including waveguides for near infrared telecommunication region. Based on the results presented in this study, the low electrical resistivity and high optical transmittance of AZO films suggested a possibility for the application in the flexible electronic devices, such as transparent conducting oxide film on LEDs, solar cells, and touch panels.

Dondapati, Hareesh; Santiago, Kevin; Pradhan, A. K.

2013-10-01

92

Model for thickness dependence of mobility and concentration in highly conductive zinc oxide  

NASA Astrophysics Data System (ADS)

The dependences of the 294 and 10 K mobility ? and volume carrier concentration n on thickness (d=25 to 147 nm) are examined in aluminum-doped zinc oxide (AZO). Two AZO layers are grown at each thickness, one with and one without a 20-nm-thick ZnON buffer layer. Plots of the 10 K sheet concentration ns versus d for buffered (B) and unbuffered (UB) samples give straight lines of similar slope, n=8.36×1020 and 8.32×1020 cm-3, but different x-axis intercepts, ?d=-4 and +13 nm, respectively. Plots of ns versus d at 294 K produce substantially the same results. Plots of ? versus d can be well fitted with the equation ?(d)=?(?)/[1+d*/(d-?d)], where d* is the thickness for which ?(?) is reduced by a factor 2. For the B and UB samples, d*=7 and 23 nm, respectively, showing the efficacy of the ZnON buffer. Finally, from n and ?(?) we can use degenerate electron scattering theory to calculate bulk donor and acceptor concentrations of 1.23×1021 cm-3 and 1.95×1020 cm-3, respectively, and Drude theory to predict a plasmonic resonance at 1.34 ?m. The latter is confirmed by reflectance measurements.

Look, David C.; Leedy, Kevin D.; Kiefer, Arnold; Claflin, Bruce; Itagaki, Naho; Matsushima, Koichi; Surhariadi, Iping

2013-03-01

93

Photo-assisted hetero-fenton decolorization of azo dye from contaminated water by Fe-Si mixed oxide nanocomposite.  

PubMed

An aerogel of silica gel dopeyd with 2.86 wt% Fe was prepared by an alkoxide sol-gel method and using tetraethyl orthosilicate as a precursor material. The synthesized aerogel was calcined at 500 degress C to produce nanoparticle solids, and was characterized by XRD, FT-IR and SEM. The nanosized iron-silica gel mixed oxide was tested in the photooxidation of the azo dye Acid Red 14 (AR 14) using 30% aqueous hydrogen peroxide as oxidant and UV light. The 2.86 wt% Fe-loaded SiO2 showed very good efficiency in the decolorization of AR 14. The effects of various parameters including solution pH, catalyst, oxidant and initial dye concentrations on photodegradation were investigated and the optimum conditions were determined. The catalyst was resistant to leaching and could be recycled several times without appreciable loss of activity. PMID:22329154

Rasoulifard, M H; Monfared, H Hosseini; Masoudian, S

2011-10-01

94

Zinc poisoning  

MedlinePLUS

... preservatives, and ointments Rust prevention coatings Vitamin and mineral supplements Zinc chloride Zinc oxide (relatively nonharmful) Zinc acetate Zinc sulfate Heated or burned galvanized metal (releases zinc fumes) ...

95

Zinc oxide nanostructures and nanoengineering  

NASA Astrophysics Data System (ADS)

ZnO is a large band-gap (3.37 eV) semiconductor, a potentially important material for numerous optoelectronic applications. Nanostructures, by definition are the structures having at least one dimension between 1--100 nm. In this thesis we will investigate a brief account of the strategies to grow ZnO nanostructures. Since invariably nanomaterial properties tend to change significantly during scale-up from development on limited volume equipment. Goal of this study is to demonstrate a practical technique which is able to synthesize large quantities of nanowires while keeping the unique properties of nano-sized materials. Using ZnO as an example, we discussed a strategy to produce nanowires in gram quantity. Ability to define position, size, and density of nanostructures on surfaces enable detailed studies of the properties of individual sites as well as collective properties of the assembly. These periodic structures are usually manufactured using electron beam lithography, photolithography, or x-ray lithography techniques. These methods allow fabrication of nanostructures and provide highly reproducible results. However, they are mostly not scalable to large areas, and are limited by a multistage, time-consuming, and expensive preparation procedure. We described an unique technique combining nanosphere self-assembly lithography and vapor-liquid-solid (VLS) approach of fabricating periodic array of catalyst dots in various geometry and subsequently grow vertically aligned ZnO nanowires in a large area hoping to achieve enhanced ultraviolet lasing and many other photonic devices. ZnO being a transparent conducting oxide, the fabrication of ZnO field emitters can be easily integrated with ITO and ZnO thin film fabrication process. Thus a low cost solution for fabrication of field emission display can be realized using ZnO nanowires as field emitters. There have been several demonstrations of using ZnO nanowires as field emitters. However no significant improvement in terms of field enhancement factor or turn on voltage has been achieved. Most of these nanowires were grown on smooth substrate. We will discuss effect of substrate geometry on field emission properties of nanostructures. We choose carbon cloth as an example, where the woven cloth geometry combined with the high aspect ratio of the nanowires significantly improved the field emission property.

Banerjee, Debasish

96

Varistor action in zinc oxide suspension  

NASA Astrophysics Data System (ADS)

In a suspension composed of zinc oxide (ZnO) particles and silicone oil, it is found that the current density dramatically increases above a specific electric field (break down field Eb). In ac measurement, the nonlinear coefficient (?), which characterizes the relationship between current density J and the electric field E as J~E?, changes from ~1 to ~30 when increasing the electric field through Eb. On the basis of the ? value, temperature dependence of Eb, etc., the mechanism of the fluid varistor is briefly discussed.

Negita, K.; Yamaguchi, T.; Tsuchie, T.; Shigematsu, N.

2003-04-01

97

Cyclic voltammetric study of zinc and zinc oxide electrodes in 5.3 M KOH  

Microsoft Academic Search

The behaviour of zinc and zinc oxide in 5.3 M KOH in the presence of alkaline earth oxides, SnO, Ni(OH)2 and Co(OH)2 was examined by cyclic voltammetry. The influence of the alkaline earth oxides was compared with additives of established effects (Bi2O3, LiOH, Na2CO3 and CdO). The alkaline earth oxide each exhibits a distinct behaviour towards zincate. Whereas, a single

R. Renuka; L. Srinivasan; S. Ramamurthy; A. Veluchamy; N. Venkatakrishnan

2001-01-01

98

Electrochemical oxidation of an azo dye in aqueous media investigation of operational parameters and kinetics  

Microsoft Academic Search

In this research two types of electrochemical reactors for the treatment of simulated wastewaters containing Direct blue 71 azo dye (DB71) were used: (1) Laboratory scale undivided electrolysis cell system (450mL volume) with one 2cm×2cm platinum plate as the anode placed in the middle of the cell and two 2cm×8cm steel plates (SS-304) as cathodes placed in the sides of

J. Basiri Parsa; M. Rezaei; A. R. Soleymani

2009-01-01

99

Photochemical oxidation of reactive azo dye with UV–H 2O 2 process  

Microsoft Academic Search

The photooxidation of a chlorotriazine reactive azo dye Reactive Orange 4 has been carried out in the presence of H2O2 using UV-A light. The effects of reaction pH, applied H2O2 dose, UV light power have been studied. These parameters strongly influence the decolourisation and degradation. The increase of initial dye concentration decreases the removal rate. The kinetics of decolourisation and

M. Muruganandham; M. Swaminathan

2004-01-01

100

Elemental vapor-phase synthesis of nanostructured zinc oxide  

Microsoft Academic Search

We systematize experimental data on the elemental vapor-phase synthesis of zinc oxide nanocrystal arrays on substrates. This\\u000a process may yield nanostructures differing in shape and dimensions, in particular, well-aligned ZnO nanorod arrays. A model\\u000a is proposed in which aligned zinc oxide nanorod arrays may grow by the vapor-liquid-solid (VLS) mechanism, and liquid zinc\\u000a nanodroplets forming on the substrate surface at

A. N. Red’kin; Z. I. Makovei; A. N. Gruzintsev; E. E. Yakimov; O. V. Kononenko; A. A. Firsov

2009-01-01

101

Film-type field triode based on zinc oxide  

Microsoft Academic Search

The aim of the present investigation was to prepare and study triode structures based on zinc oxide. So far there has only been one paper on this problem; it related to triodes based on a zinc oxide single crystal [2]. The instrument has a low control transconductance (10 p A\\/V for S V on the sink electrode) and no region

V. V. Mokrousov; V. A. Khanin

1971-01-01

102

Piezoelectric Nanogenerators Based on Zinc Oxide Nanowire Arrays  

Microsoft Academic Search

We have converted nanoscale mechanical energy into electrical energy by means of piezoelectric zinc oxide nanowire (NW) arrays. The aligned NWs are deflected with a conductive atomic force microscope tip in contact mode. The coupling of piezoelectric and semiconducting properties in zinc oxide creates a strain field and charge separation across the NW as a result of its bending. The

Zhong Lin Wang; Jinhui Song

2006-01-01

103

Catalytic conversion of biomass pyrolysis vapours with zinc oxide  

Microsoft Academic Search

Conversion of pyrolysis vapours of pine sawdust was studied in micro and bench scales with zinc oxide catalyst. Three different zinc oxides were screened in a gas chromatograph system using an injection port as a fixed-bed catalytic converter in order to find appropriate reaction conditions by emphasising a high yield of bio-oil. Catalytically treated pyrolysis oils were produced in a

M. I Nokkosmäki; E. T Kuoppala; E. A Leppämäki; A. O. I Krause

2000-01-01

104

The enhanced conductivity of AZO thin films on soda lime glass with an ultrathin Al2O3 buffer layer  

NASA Astrophysics Data System (ADS)

Aluminum doped zinc oxide (AZO) films were deposited by radio frequency (RF) magnetron sputtering on the Al2O3-coated and bare soda lime glass substrates, respectively. The properties of AZO films were analyzed using X-ray diffraction (XRD), atomic force microscope (AFM), Hall effect measurement and ultraviolet-visible (UV-vis) spectrophotometer. The results of XRD measurement showed that all the AZO thin films had a preferentially oriented (0 0 2) peak and the intensity of (0 0 2) peak decreased with increase in the thickness of the Al2O3 buffer layer. The Hall measurement results showed that the conductivity of the AZO film with a 3 nm Al2O3 buffer layer had a remarkable 41.3% increase when compared with that of the single AZO film. The figures of merit from optical transmittance and electrical conductivity for AZO films on the 3 nm Al2O3-coated and bare glass substrates were 5466 and 3772 S cm-1, respectively. All the results suggested that the use of an ultrathin Al2O3 buffer layer effectively improved the quality of AZO film on the glass substrate.

Lu, Linfeng; Shen, Honglie; Jiang, Feng; Yang, Chao; Lin, Long

2010-08-01

105

Interface effects in zinc oxide varistors  

NASA Astrophysics Data System (ADS)

Zinc oxide varistors are electronic ceramic materials whose electrical behavior is dominated by grain boundary interface states. The unique properties of varistor ceramics are determined by the segregation of certain impurity atoms to the grain interface, creating electrical barriers to current flow. At low voltages, electrons transfer over these barriers by thermionic emission. At a critical voltage, electrons transferred over the grain interface have sufficient energy to create minority barriers (holes). These holes act to dramatically decrease the grain boundary electrical barriers leading to the observed rapid increase in current flow. Hole creation has recently been verified by optical means. Measurements of varistor degradation, varistor oxidation-reduction phenomena, and the behavior of primitive varistors with only modest current-voltage nonlinearity indicate that more than one parallel leakage path can control the varistor characteristics at lower currents.

Levinson, L. M.; Phillip, H. R.; Sonder, E.

1986-08-01

106

Application of a structure/oxidation-state correlation to complexes of bridging azo ligands.  

PubMed

Based on data from more than 40 crystal structures of metal complexes with azo-based bridging ligands (2,2'-azobispyridine, 2,2'-azobis(5-chloropyrimidine), azodicarbonyl derivatives), a correlation between the N-N bond lengths (d(NN)) and the oxidation state of the ligand (neutral, neutral/back-donating, radical-anionic, dianionic) was derived. This correlation was applied to the analysis of four ruthenium compounds of 2,2'-azobispyridine (abpy), that is, the new asymmetrical rac-[(acac)(2)Ru1(?-abpy)Ru2(bpy)(2)](ClO(4))(2) ([1](ClO(4))(2)), [Ru(acac)(2)(abpy)] (2), [Ru(bpy)(2)(abpy)](ClO(4))(2) ([3](ClO(4))(2)), and meso-[(bpy)(2)Ru(?-abpy)Ru(bpy)(2)(ClO(4))(3) ([4](ClO(4))(3); acac(-) =2,4-pentanedionato, bpy=2,2'-bipyridine). In agreement with DFT calculations, both mononuclear species 2 and 3(2+) can be described as ruthenium(II) complexes of unreduced abpy(0), with 1.295(5)oxidation of compound 1(2+) was found to mainly involve the central ligand to produce an (abpy(0))-bridged Class I mixed-valent Ru1(III)Ru2(II) species, the first reduction of compound 1(2+) affected both the bridge and Ru1 atom to form a radical complex (1(+)), with considerable metal participation in the spin-distribution. Further reduction moves the spin towards the {Ru2(bpy)(2)} entity. PMID:22837139

Das, Amit; Scherer, Thomas Michael; Mobin, Shaikh M; Kaim, Wolfgang; Lahiri, Goutam Kumar

2012-07-26

107

Photocatalytic degradation for methylene blue using zinc oxide prepared by codeposition and sol–gel methods  

Microsoft Academic Search

Zinc oxide nanoparticle was obtained by zinc hydrate deposited on the silica nanoparticle surface and zinc hydrate was dispersed in starch gel. The structure of zinc oxide particle was characterized by nitrogen adsorption–desorption and XRD, the morphology was observed by TEM. The result showed that the zinc oxide nanoparticle deposited on the silica nanoparticle surface was well-dispersed and less than

Wenzhong Shen; Zhijie Li; Hui Wang; Yihong Liu; Qingjie Guo; Yuanli Zhang

2008-01-01

108

Nucleation effects on structural and optical properties of electrodeposited zinc oxide on tin oxide  

Microsoft Academic Search

Zinc oxide was electrodeposited from oxygenated aqueous solutions of zinc chloride at 80 °C on tin oxide covered glass substrates. A new activation treatment for the substrate is established. This consists in the initial formation, in the deposition solution, of a thin metallic zinc layer (5–50 nm) converted to ZnO by in situ reoxidation. Variable densities of nucleation centers (with

B. Canava; D. Lincot

2000-01-01

109

Decolorization of an azo dye Orange G in aqueous solution by Fenton oxidation process: Effect of system parameters and kinetic study  

Microsoft Academic Search

To establish cost-efficient operating conditions for potential application of Fenton oxidation process to treat wastewater containing an azo dye Orange G (OG), some important operating parameters such as pH value of solutions, dosages of H2O2 and Fe2+, temperature, presence\\/absence of chloride ion and concentration of the dye, which effect on the decolorization of OG in aqueous solution by Fenton oxidation

Sheng-Peng Sun; Cheng-Jie Li; Jian-Hui Sun; Shao-Hui Shi; Mao-Hong Fan; Qi Zhou

2009-01-01

110

Magnetic nanobelts of iron-doped zinc oxide  

SciTech Connect

Magnetic nanobelts of iron-doped zinc oxide were fabricated by vapor-phase transport using zinc oxide, iron oxide, and graphite as source materials. The nanobelts grew mainly along [1010] orientation and enclosed by {+-}(0001) and {+-}(1210) surfaces. The measurements of x-ray diffraction, energy-dispersive x-ray spectroscopy, and high-resolution transmission electron microscopy demonstrated that iron was doped into the nanobelts. As a result, the nanobelts were magnetic.

Xu, C.X.; Sun, X.W.; Dong, Z.L.; Yu, M.B.; Xiong Yongzhong; Chen, J.S. [School of Electric and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore); School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore); Institute of Microelectronics, 11 Science Park Road, Science Park II, Singapore 117684 (Singapore); Data Storage Institute, 5 Engineering Drive 1, Singapore 117684 (Singapore)

2005-04-25

111

Growth and characterization of zinc oxide nanoneedles.  

PubMed

Crystalline zinc oxide (ZnO) nanoneedles were grown on n type Si(100) substrates using different catalyst of variable thicknesses by using thermal evaporation of ZnO and graphite powder in a tube with an Ar as a carrier gas. During the growth the temperature of the substrate was kept around 900-980 degrees C. The growth of ZnO nanoneedles was done by the Vapour-Liquid-Solid (VLS) method. The catalysts used in the experiments were gold (Au) and cobalt (Co). The shape and morphology of the nanoneedles were investigated by Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS) and Raman Spectroscopy. Different shaped nanoneedles were obtained on the catalysts. Raman scattering were used to characterize the structural properties and crystal quality of the obtained nanostructures. The composition details of nanoneedle were studied by XPS. PMID:19916458

Kumari, Puja; Roy, Susanta Sinha; McLaughlin, James

2009-07-01

112

Ultra-thin zinc oxide film on Mo(100)  

Microsoft Academic Search

Zinc oxide films on a single crystal Mo(100) substrate were fabricated by annealing the pre-deposited metal Zn films in 10?5–10?4 Pa O2 ambience at 300–525 K, and were characterized by in situ Auger electron spectroscopy, electron energy loss spectroscopy, low energy electron diffraction and high-resolution electron energy loss spectroscopy. The results show that the atomic ratio of oxygen to zinc in zinc

Kefei Zheng; Qinlin Guo; Mingshan Xue; Donghui Guo; Shuang Liu; E. G. Wang

2007-01-01

113

Photooxidation of azo dye reactive black 5 using a novel supported iron oxide: heterogeneous and homogeneous approach.  

PubMed

Photooxidation of azo dye Reactive Black 5 (RB5) by H202 was performed with a novel supported iron oxide in a batch reactor in the range of pH 2.5-6.0. The iron oxide was prepared through a fluidized-bed reactor (FBR) and much cheaper than the Nafion-based catalysts. Experimental results indicate that the iron oxide can significantly accelerate the degradation of RB5 under the irradiation of UVA light (wavelength = 365 nm). An advantage of the catalyst is its long-term stability, which was confirmed through using the catalyst for multiple runs in the degradation of RB5. In addition, this study focused mainly on determining the proportions of homogeneous catalysis and heterogeneous catalysis in the batch reactor. Conclusively, although heterogeneous catalysis contributes primarily to the oxidation of RB5 during pH 4.5-6.0, the homogeneous catalysis is of increasing importance below pH 4.0 because of the Fe ions leaching from the catalyst to solution. PMID:16749458

Hsueh, C L; Huang, Y H; Wang, C C; Chen, C Y

2006-01-01

114

The enhanced conductivity and stability of AZO thin films with a TiO2 buffer layer  

NASA Astrophysics Data System (ADS)

Aluminum doped zinc oxide (AZO) films were substitutes of the SnO2:F films on soda lime glass substrate in the amorphous thin-film solar cells due to good properties and low cost. In order to improve properties of AZO films, the TiO2 buffer layer had been introduced. AZO films with and without TiO2 buffer layer were deposited on soda lime glass substrates by r.f. magnetron sputtering. Subsequently, one group samples were annealed in vacuum (0.1 Pa) at 500 °C for 120 s using the RTA system, and the influence of TiO2 thickness on the properties of AZO films had been discussed. The XRD measurement results showed that all the films had a preferentially oriented (0 0 2) peak, and the intensity of (0 0 2) peak had been enhanced for the AZO films with TiO2 buffer layer. The resistivity of TiO2 (3.0 nm)/AZO double-layer film is 4.76×10-4 ? cm with the maximum figure merit of 1.92×10-2 ?-1, and the resistivity has a remarkable 28.7% decrease comparing with that of the single AZO film. The carrier scattering mechanism of TiO2 (3.0 nm)/AZO double-layer film had been described by Hall measurement in different temperatures. The average transmittance of all the films exceeded 92% in the visible spectrum. Another group samples were heat treated in the quartz tube in air atmosphere, and the effect of TiO2 thickness on thermal stability of AZO films had been discussed.

Yang, Tianlin; Song, Shumei; Li, Yanhui; Xin, Yanqing; Du, Guiqiang; Lv, Maoshui; Han, Shenghao

2012-12-01

115

A review of zinc oxide mineral beneficiation using flotation method.  

PubMed

In recent years, extraction of zinc from low-grade mining tailings of oxidized zinc has been a matter of discussion. This is a material which can be processed by flotation and acid-leaching methods. Owing to the similarities in the physicochemical and surface chemistry of the constituent minerals, separation of zinc oxide minerals from their gangues by flotation is an extremely complex process. It appears that selective leaching is a promising method for the beneficiation of this type of ore. However, with the high consumption of leaching acid, the treatment of low-grade oxidized zinc ores by hydrometallurgical methods is expensive and complex. Hence, it is best to pre-concentrate low-grade oxidized zinc by flotation and then to employ hydrometallurgical methods. This paper presents a critical review on the zinc oxide mineral flotation technique. In this paper, the various flotation methods of zinc oxide minerals which have been proposed in the literature have been detailed with the aim of identifying the important factors involved in the flotation process. The various aspects of recovery of zinc from these minerals are also dealt with here. The literature indicates that the collector type, sulfidizing agent, pH regulator, depressants and dispersants types, temperature, solid pulp concentration, and desliming are important parameters in the process. The range and optimum values of these parameters, as also the adsorption mechanism, together with the resultant flotation of the zinc oxide minerals reported in the literature are summarized and highlighted in the paper. This review presents a comprehensive scientific guide to the effectiveness of flotation strategy. PMID:23571227

Ejtemaei, Majid; Gharabaghi, Mahdi; Irannajad, Mehdi

2013-03-13

116

Interfacial electron transfer dynamics of photosensitized zinc oxide nanoclusters.  

National Technical Information Service (NTIS)

The authors have prepared and characterized photosensitized zinc oxide (ZnO) nanoclusters, dispersed in methanol, using carboxylated coumarin dyes for surface adsorption. Femtosecond time-resolved emission spectroscopy allows the authors to measure the ph...

K. Murakoshi S. Yanagida M. Capel

1997-01-01

117

Synthesis of epitaxial layers of zinc oxide on nonorienting substrates  

Microsoft Academic Search

The first experiments on the growth of single-crystal layers of zinc oxide on nonorienting substrates (crystalline leucosapphire\\u000a and fused quartz) by chemical transport reactions in a reduced-pressure flow-through reactor in a hydrogen atmosphere is reported.\\u000a To ensure autoepitaxy on a surface of a nonorienting substrate, an optimized intermediate layer of zinc oxide of thickness\\u000a 200–1000 , which provides a texture

B. M. Ataev; I. K. Kamilov; A. M. Bagamadova; V. V. Mamedov; A. K. Omaev; M. Kh. Rabadanov

1999-01-01

118

CO2 gas sensitivity of sputtered zinc oxide thin films  

Microsoft Academic Search

For the first time, sputtered zinc oxide (ZnO) thin films have been used as a CO2 gas sensor. Zinc oxide thin films have been synthesized using reactive d.c. sputtering method for gas sensor applications, in the deposition temperature range from 130-153°C at a chamber pressure of 8?5 mbar for 18 h. Argon and oxygen gases were used as sputtering and

119

Amorphous Zinc-Oxide-Based Thin-film Transistors  

Microsoft Academic Search

Recently, RF-sputtered zinc oxide-based field effect transisters (FETs) have been demonstrated with higher mobilities and performance than amorphous silicon, the dominant material used for display backplanes [1,2]. The low temperature processing possible for zinc oxide-based FETs [3] makes these materials compatible with flexible polymer substrates, but patterning with shadow masks limits feature size and accuracy. This project aims to develop

A. Wang; I. Kymissis; P. Mardilovich; V. Bulovic; C. G. Sodini; A. I. Akinwande

2005-01-01

120

CO 2 gas sensitivity of sputtered zinc oxide thin films  

Microsoft Academic Search

For the first time, sputtered zinc oxide (ZnO) thin films have been used as a CO2 gas sensor. Zinc oxide thin films have been synthesized using reactive d.c. sputtering method for gas sensor applications,\\u000a in the deposition temperature range from 130–153°C at a chamber pressure of 8·5 mbar for 18 h. Argon and oxygen gases were\\u000a used as sputtering and

P. Samarasekara; N. T. R. N. Kumara; M. V. K. Perera

2007-01-01

121

Zinc oxide nanowire rigid platforms on elastomeric substrates.  

PubMed

Zinc oxide nanostructured thin films are transparent semiconducting ceramics increasingly used in a wide range of integrated devices. This paper outlines a simple strategy to integrate arrays of zinc oxide nanostructured thin films on elastomeric substrates using templated patterning. The arrays are robust to large uniaxial strains (up to 20% strain), do not fracture, and maintain electrical functionality. The integration of brittle nanostructured semiconducting materials on elastomeric substrates opens promising routes for the manufacture of deformable and stretchable electronics. PMID:21740041

Bendall, James S; Graz, Ingrid; Lacour, Stéphanie P

2011-07-19

122

Zinc oxide nanoflowers make new blood vessels  

NASA Astrophysics Data System (ADS)

It is well established that angiogenesis is the process of formation of new capillaries from pre-existing blood vessels. It is a complex process, involving both pro- and anti-angiogenic factors, and plays a significant role in physiological and pathophysiological processes such as embryonic development, atherosclerosis, post-ischemic vascularization of the myocardium, tumor growth and metastasis, rheumatoid arthritis etc. This is the first report of zinc oxide (ZnO) nanoflowers that show significant pro-angiogenic properties (formation of new capillaries from pre-existing blood vessels), observed by in vitro and in vivo angiogenesis assays. The egg yolk angiogenesis assay using ZnO nanoflowers indicates the presence of matured blood vessels formation. Additionally, it helps to promote endothelial cell (EA.hy926 cells) migration in wound healing assays. Formation of reactive oxygen species (ROS), especially hydrogen peroxide (H2O2)--a redox signaling molecule, might be the plausible mechanism for nanoflower-based angiogenesis. Angiogenesis by nanoflowers may provide the basis for the future development of new alternative therapeutic treatment strategies for cardiovascular and ischemic diseases, where angiogenesis plays a significant role.It is well established that angiogenesis is the process of formation of new capillaries from pre-existing blood vessels. It is a complex process, involving both pro- and anti-angiogenic factors, and plays a significant role in physiological and pathophysiological processes such as embryonic development, atherosclerosis, post-ischemic vascularization of the myocardium, tumor growth and metastasis, rheumatoid arthritis etc. This is the first report of zinc oxide (ZnO) nanoflowers that show significant pro-angiogenic properties (formation of new capillaries from pre-existing blood vessels), observed by in vitro and in vivo angiogenesis assays. The egg yolk angiogenesis assay using ZnO nanoflowers indicates the presence of matured blood vessels formation. Additionally, it helps to promote endothelial cell (EA.hy926 cells) migration in wound healing assays. Formation of reactive oxygen species (ROS), especially hydrogen peroxide (H2O2)--a redox signaling molecule, might be the plausible mechanism for nanoflower-based angiogenesis. Angiogenesis by nanoflowers may provide the basis for the future development of new alternative therapeutic treatment strategies for cardiovascular and ischemic diseases, where angiogenesis plays a significant role. Electronic supplementary information (ESI) available: See DOI: 10.1039/c2nr32369a

Barui, Ayan Kumar; Veeriah, Vimal; Mukherjee, Sudip; Manna, Joydeb; Patel, Ajay Kumar; Patra, Sujata; Pal, Krishnendu; Murali, Shruthi; Rana, Rohit K.; Chatterjee, Suvro; Patra, Chitta Ranjan

2012-11-01

123

Degradation of commercial azo dyes in water using ozonation and UV enhanced ozonation process  

Microsoft Academic Search

The chemical oxidation of eight non-biodegradable azo dyes by ozonation and photooxidation process was studied in a pilot scale photochemical (UV\\/ozone) reactor. In experiments with ozone bubbling, the degradation of eight azo dyes was found to occur in the absence of UV light. The degradation rate of azo dyes was observed to be first order with respected to both azo

Hung-Yee Shu; Ching-Rong Huang

1995-01-01

124

Atom Probe Tomography of Zinc Oxide Nanowires  

NASA Astrophysics Data System (ADS)

Wide-bandgap zinc oxide (ZnO) semiconductors and nanowires have become important materials for electronic and photonic device applications. In this work, we report the growth of well-aligned single-crystal ZnO nanowire arrays on sapphire substrates by chemical vapor deposition and the development of atom probe tomography, an emerging nanoscale characterization method capable of providing deeper insight into the three-dimensional distribution of atoms and impurities within its structure. Using a metal-catalyst-free approach, the influence of the growth parameters on the orientation and density of the nanowires were studied. The resulting ZnO nanowires were determined to be single crystalline, with diameter on the order of 50 nm to 150 nm and length that could be controlled between 0.5 ?m to 20 ?m. Their density was on the order of high 108 cm-2 to low 109 cm-2. In addition to routine characterizations using scanning and transmission electron microscopy, x-ray diffraction, photoluminescence, and Raman spectroscopy, we developed the atom probe tomography technique for ZnO nanowires, comparing the voltage pulse and laser pulse modes. In-depth analysis of the data was carried out to determine the accurate chemical composition of the nanowires and reveal the incorporation of nitrogen impurities. The current-voltage characteristics of individual nanowires were measured to determine their electrical properties.

Dawahre, Nabil; Shen, Gang; Balci, Soner; Baughman, William; Wilbert, David S.; Harris, Nick; Butler, Lee; Martens, Rich; Kim, Seongsin Margaret; Kung, Patrick

2012-05-01

125

Sliding droplets on superomniphobic zinc oxide nanostructures.  

PubMed

This study reports on liquid-repellency of zinc oxide nanostructures (ZnO NS). The ZnO NS are synthesized by an easy and fast chemical bath deposition technique. Three different nanostructured surfaces consisting of nanorods, flowers, and particles are prepared, depending on the deposition time and the presence of ethanolamine in the reaction mixture. Chemical functionalization of the ZnO NS with 1H,1H,2H,2H-perfluorodecyltrichlorosilane (PFTS) in liquid (PFTS L) and vapor phase (PFTS V) or through octafluorobutane (C(4)F(8)) plasma deposition led to the formation of superomniphobic surfaces. A comprehensive characterization of the wetting properties (static contact angle and contact angle hysteresis) has been performed using liquids composed of deionized water and various concentrations of ethanol (surface tension between 35 and 72.6 mN/m). Depending on the nanostructures morphology, coating nature and liquid employed, high static apparent contact angles ? ? 150-160°, and low contact angle hysteresis ?? ? 0° are obtained. The different ZnO NS are characterized using scanning electron microscopy (SEM) and contact angle measurements. The results reported in this work permit preparation of sliding omniphobic surfaces using a simple and low cost technique. PMID:22053956

Perry, Guillaume; Coffinier, Yannick; Thomy, Vincent; Boukherroub, Rabah

2011-11-30

126

Zinc Oxide Transparent Thin Films For Optoelectronics  

NASA Astrophysics Data System (ADS)

The object of this body of work is to study the properties and suitability of zinc oxide thin films with a view to engineering them for optoelectronics applications, making them a cheap and effective alternative to indium tin oxide (ITO), the most used transparent conducting oxides in the industry. Initially, a study was undertaken to examine the behavior of silver contacts to ZnO and ITO during thermal processing, a step frequently used in materials processing in optoelectronics. The second study involved an attempt to improve the conductivity of ZnO films by inserting a thin copper layer between two ZnO layers. The Hall resistivity of the films was as low as 6.9x10 -5 O-cm with a carrier concentration of 1.2x10 22 cm-3 at the optimum copper layer thickness. The physics of conduction in the films has been examined. In order to improve the average visible transmittance, we replaced the copper layer with gold. The films were then found to undergo a seven orders of magnitude drop in effective resistivity from 200 O-cm to 5.2x10-5 O-cm The films have an average transmittance between 75% and 85% depending upon the gold thickness, and a peak transmittance of up to 93%. The best Haacke figure of merit was 15.1x10-3 O-1. Finally, to test the multilayer transparent electrodes on a device, ZnO/Au/ZnO (ZAZ) electrodes were evaluated as transparent electrodes for organic light-emitting devices (OLEDs). The electrodes exhibited substantially enhanced conductivity (about 8x10-5 O-cm) over conventional indium tin oxide (ITO) electrodes (about 3.2x10-5 O-cm). OLEDs fabricated with the ZAZ electrodes showed reduced leakage compared to control OLEDs on ITO and reduced ohmic losses at high current densities. At a luminance of 25000 cd/m2, the lum/W efficiency of the ZAZ electrode based device improved by 5% compared to the device on ITO. A normalized intensity graph of the colour output from the green OLEDs shows that ZAZ electrodes allow for a broader spectral output in the green wavelength region of peak photopic sensitivity compared to ITO. The results have implications for electrode choice in display technology.

Sivaramakrishnan, Karthik

127

Growth and Characterization of Digitally Alloyed Zinc Oxide Based TCOs  

NASA Astrophysics Data System (ADS)

Transparent conducting oxides (TCOs) based on substitutionally doped zinc oxide and novel amorphous oxides offer the potential of high performance and low cost for organic solid-state lighting and organic photovoltaic (OPV) applications. We present studies on digitally alloyed amorphous indium zinc oxide (InZnO) with crystalline gallium doped zinc oxide (GaZnO) and zinc tin oxide (ZnSnO3). The films were grown using pulse laser deposition system with varying oxygen pressure. Alternating layers of two constituent materials are deposited with periodicity of around 5 nm. We find that the composite material has similar conductivity as the constituent species grown at similar conditions but the surface roughness and the work function are determined solely by the terminating layer. We observe that both IZO and GZO terminated stacks result in conductivity of 1.5E3 S/cm, but the surface roughness varies from 0.3 nm to 0.7 nm respectively. We also explore other possible combination of zinc based oxide materials in order to optimize the optical and the electrical properties of TCO for possible application in opto-electronic devices.

Sigdel, Ajaya; Shaheen, Sean; Perkins, John; Ginley, David; Berry, Joseph

2009-10-01

128

Predicting azo dye toxicity  

Microsoft Academic Search

Literature regrading azo dye carcinogenicity was examined to establish, if possible, guidelines to predict the human health risks of new azo dyes. Three different mechanisms for azo dye carcinogenicity were identified, all involving metabolic activation to reactive electrophilic intermediates that covalently bind DNA. In the order of decreasing number of published references, these mechanisms are 1. Azo dyes that are

Mark A. Brown; Stephen C. De Vito

1993-01-01

129

Morphological Control of Metal Oxide-Doped Zinc Oxide and Application to Cosmetics  

NASA Astrophysics Data System (ADS)

Zinc oxide shows excellent transparency and ultraviolet radiation shielding ability, and is used for various cosmetics.1-3 However, it possesses high catalytic activity and lower dispersibility. Therefore, spherical particles of zinc oxide have been synthesized by soft solution reaction using zinc nitrate, ethylene glycol, sodium hydroxide and triethanolamine as starting materials. After dissolving these compounds in water, the solution was heated at 90°C for 1 h to form almost mono-dispersed spherical zinc oxide particles. The particle size changed depending on zinc ion concentration, ethylene glycol concentration and so on. Furthermore, with doping some metal ions, the phtocatalytic activity could be decreased. The obtained monodispersed metal ion-doped spherical zinc oxides showed excellent UV shielding ability and low photocatalytic activity. Therefore, they are expected to be used as cosmetics ingredients.

Goto, Takehiro; Yin, Shu; Sato, Tsugio; Tanaka, Takumi

2012-06-01

130

XPS characterisation of plasma treated and zinc oxide coated PET  

NASA Astrophysics Data System (ADS)

At first, X-ray photoelectron spectroscopy (XPS) analyses of reference and carbon dioxide plasma treated polyethylene terephthalate (PET) were carried out. Significant chemical modifications were outlined in the treated PET surface in comparison with the reference one. The formation of new oxygenated groups was evidenced. These modifications heighten the level of interactions between the polymer substrate and the deposited coating. In a second stage, zinc oxide thin films were elaborated by r.f. magnetron sputtering from a ceramic target and with a reactive gas (mixture of argon-1% oxygen) under optimised conditions on CO 2 plasma treated PET. The interfacial chemistry between the plasma treated PET and the zinc oxide was also studied by XPS. The line shape changes in the high-resolution core level spectra of carbon C1s, oxygen O1s, and zinc (Zn2p3/2, Zn3p), with the progressive deposition of zinc oxide coatings being recorded. The obtained spectra were fitted to mixed Gaussian-Lorentzian components using XPS CASA software. An interaction scheme between the zinc oxide thin layer and its polymer substrate, in the first stage of deposition, was proposed and checked by corroborating the findings of the different XPS spectra and their decompositions. It suggests the formation of Zn sbnd O sbnd C complexes at the interface, which are promoted by an electron transfer from zinc to oxygen in oxygenated species, mainly alcohol groups, generated by the CO 2 plasma treatment of PET.

Amor, S. Ben; Jacquet, M.; Fioux, P.; Nardin, M.

131

Zinc oxide - a material for energy applications  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) is a wide-band-gap semiconductor that has attracted resurgent interest as an electronic material for a range of applications. The efficiency of the emission is higher than more conventional materials such as GaN, making ZnO a strong candidate for energy-efficient white lighting. Another major advantage of ZnO is the fact that, in contrast to GaN, large single crystals can be grown. ZnO has been used as a transparent conductor in solar cells, and is a preferred material in transparent transistors, ``invisible'' devices which could be very useful in products such as liquid-crystal displays. In addition to optoelectronic and electronic devices, ZnO has emerged as a potentially important material for spintronic applications. Despite its numerous advantages and potential applications, ZnO suffers from a relatively high level of donor defects. These compensating impurities prevent p- type doping, which is essential for practical applications. In our work, we have focused on hydrogen donors in bulk ZnO, combining IR spectroscopy with electrical measurements. As dimensions approach the nano-scale, the vastly increased surface-to-volume ratio leads to interesting phenomena. At moderate annealing temperatures (350 C), hydrogen permeates nanoparticles, resulting in a dramatic increase in electrical conductivity, free-carrier absorption, and infrared reflectivity. These results could be relevant to hydrogen sensing and storage applications. To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.NWS07.B1.1

McCluskey, Matthew

2007-05-01

132

An ellipsometric study of oxide film formation on zinc electrodes  

Microsoft Academic Search

A combination of experimental techniques to investigate and compare the growth kinetics, structure, composition and growth mechanism of oxide films on zinc electrodes prepared by anodizations in aqueous solutions of potassium hydroxide and in oxygen in the form of a glow discharge plasma. Electrical measurements and ellipsometry were used to monitor and study the oxide films as they were produced.

C. E. Mueller

1977-01-01

133

Cytochrome P-450 dependent monooxygenases model system: rapid and efficient oxidation of primary aromatic amines to azo derivatives with sodium periodate catalyzed by manganese(III) Schiff base complexes.  

PubMed

Rapid and efficient oxidation of primary aromatic amines was investigated. Mn(III)-salophen catalyst can catalyze the oxidation of primary aromatic amines to azo derivatives with sodium periodate. The ability of various Schiff base complexes in this oxidation system was also investigated. PMID:15358293

Mirkhani, Valiollah; Tangestaninejad, Shahram; Moghadam, Majid; Moghbel, Maryam

2004-09-01

134

Enhanced biocidal activity and optical properties of zinc oxide nanoneedles  

NASA Astrophysics Data System (ADS)

Zinc oxide nanoneedles were successfully synthesized by simple wet chemical method. X-ray diffraction studies reveal the formation of wurtzite-type of ZnO. Optical studies indicate the presence of defects in the form of oxygen vacancies and zinc interstitials. As an application study, this sample was tested for its antibacterial activity. These nanoneedles were found to exhibit excellent biocidal activity against both gram positive and gram negative bacteria.

Ramani, Meghana; Ponnusamy, S.; Muthamizhchelvan, C.

2012-06-01

135

Characterization of zinc oxide and zinc ferrite doped with Ti or Cu as sorbents for hot gas desulphurization  

Microsoft Academic Search

Three series of samples based on zinc oxide and zinc ferrite doped with copper or titanium oxides have been prepared in order to improve their performance as regenerable sorbents for hot gas desulphurization. In each series the oxide concentration was varied over a broad range to enhance the formation of different chemical species. The stability against reducing agents and the

Miguel Pineda; José L. G. Fierro; José M. Palacios; Cristina Cilleruelo; Enrique García; José V. Ibarra

1997-01-01

136

Preparation and properties of transparent conducting zinc oxide and aluminium-doped zinc oxide films prepared by evaporating method  

Microsoft Academic Search

Undoped and aluminium-doped zinc oxide films have been prepared by thermal evaporation of zinc acetate [Zn(CH3COO)2 2H2O] and aluminium chloride [AlCl3] onto a heated glass substrate. The structural and optoelectrical properties of the films have been studied. The effects of heat treatment for the as-deposited films in air and vaccum are investigated. Highly transparent films with conductivity as low as

Jin Ma; Feng Ji; Hong-lei Ma; Shu-ying Li

2000-01-01

137

Optical cavity modes of a single crystalline zinc oxide microsphere.  

PubMed

A detailed study on the optical cavity modes of zinc oxide microspheres under the optical excitation is presented. The zinc oxide microspheres with diameters ranging from 1.5 to 3.0 µm are prepared using hydrothermal growth technique. The photoluminescence measurement of a single microsphere shows prominent resonances of whispering gallery modes at room temperature. The experimentally observed whispering gallery modes in the photoluminescence spectrum are compared with theoretical calculations using analytical and finite element methods in order to clarify resonance properties of these modes. The comparison between theoretical analysis and experiment suggests that the dielectric constant of the ZnO microsphere is somewhat different from that for bulk ZnO. The sharp resonances of whispering gallery modes in zinc oxide microspheres cover the entire visible window. They may be utilized in realizations of optical resonators, light emitting devices, and lasers for future chip integrations with micro/nano optoelectronic circuits, and developments of optical biosensors. PMID:23481759

Moirangthem, Rakesh Singh; Cheng, Pi-Ju; Chien, Paul Ching-Hang; Ngo, Buu Trong Huynh; Chang, Shu-Wei; Tien, Chung-Hao; Chang, Yia-Chung

2013-02-11

138

Preparation of zinc oxide\\/metal oxide multilayered thin films for low-voltage varistors  

Microsoft Academic Search

Zinc oxide\\/metal oxide multilayered composite thin film varistors have been fabricated by the radio-frequency (RF, 13.56MHz) sputtering method and the electrical properties of the films were investigated. After the Au electrode was formed on a quartz substrate by vacuum evaporation, zinc oxide (ZnO) layer was deposited by the RF sputtering with ZnO target at room temperature, Ar partial pressure of

N Horio; M Hiramatsu; M Nawata; K Imaeda; T Torii

1998-01-01

139

Fabrication of lithium-doped zinc oxide film by anodic oxidation and its ferroelectric behavior  

Microsoft Academic Search

A lithium-doped zinc oxide (ZnO) film was obtained by the anodic oxidation of a zinc sheet in a lithium hydroxide (LiOH) solution under an external DC voltage. The formation of the ZnO film on the surface of the Zn sheet is attributed to two simultaneous processes: the electrochemical oxidation of Zn to ZnO, and the chemical dissolution of ZnO. It

Ligang Yu; Gengmin Zhang; Xingyu Zhao; Dengzhu Guo

2009-01-01

140

Process optimization of Al-doped zinc oxide films as a window layer for Cu(In,Ga)Se2 thin film solar cells  

NASA Astrophysics Data System (ADS)

Al-doped zinc oxide (AZO) thin film was deposited by an in-line pulsed-DC magnetron sputtering system for Cu(In, Ga)Se2 (CIGS) solar cell and optimum process conditions were analyzed. Of several process parameters, oxygen ratio to argon gas in the sputtering ambient was intensively investigated. As increasing the oxygen concentration from 0% to 2%, carrier concentration decreased from 4.8 × 1020 to 9.7 × 1017 cm-3 and Hall mobility reduced from 6.1 to 1.1 cm2/Vs. Resultantly, the resistivity of the AZO film increased significantly from 2.2 × 10-3 up to 5.9 × 10-1 ? cm as increasing the oxygen concentration. This was due to the effect of the scattering mechanism depending on the role of the oxygen in the AZO film. The average transmittance in the range of visible light was lowest as about 74% in the film deposited without oxygen. By the way, the optical band gap was obtained with the most large value of 3.6 eV in the film deposited without oxygen. For examining the feasibility as a window layer, the optimal AZO film deposited without oxygen was applied for making the CIGS solar cell. In this CIGS solar cell, the absorber layer was formed by using the rapid thermal annealing method of CuGa/In metal precursors. The cell was satisfactorily operated with the efficiency of 7.69% even though the cell was not optimized for the buffer layer and the composition of the absorber, and had no metal grids and anti-reflection layer.

Li, Zhao-Hui; Kwon, Sang Jik

2013-11-01

141

Epitaxial growth of zinc oxide thin films on silicon (100) substrates with zirconia buffer layer  

Microsoft Academic Search

As an II-VI semiconductor, with wide bandgap and high exciton binding energy, zinc oxide has been favored for the new opto-electronic devices. One of the key issues for such applications is the integration of the zinc oxide onto silicon substrates. In this paper, we report a new integration methodology for depositing high quality zinc oxide thin films on silicon substrates.

Ravi Aggarwal; Chunming Jin; Wei Wei; Jagdish Narayan; Roger J. Narayan

2008-01-01

142

Zinc oxide synergistic systems for the weathering stabilization of polyolefin encapsulants  

Microsoft Academic Search

Zinc oxide is recognized as an unusually effective UV (opacifying) stabilizer for polyolefins, including low and high density polyethylene, polypropylene and ethylene copolymers. Zinc oxide stabilization is superior to organic UV absorbers in efficiency and economics. Synergistic organic additives used jointly with zinc oxide increase outdoor life several fold compared to the organic absorbers. Such synergists include organic phosphites (Polygard),

B. Baum; D. S. Carr

1983-01-01

143

Effect of modifying agents on the hydrophobicity and yield of zinc borate synthesized by zinc oxide  

NASA Astrophysics Data System (ADS)

The aim of this study was to synthesize zinc borate using zinc oxide, reference boric acid, and reference zinc borate (reference ZB) as the seed, and to investigate the effects of modifying agents and reaction parameters on the hydrophobicity and yield, respectively. The reaction parameters include reaction time (1-5 h), reactant ratio (H3BO3/ZnO by mass: 2-5), seed ratio (seed crystal/(H3BO3+ZnO) by mass: 0-2wt%), reaction temperature (50-120°C), cooling temperature (10-80°C), and stirring rate (400-700 r/min); the modifying agents involve propylene glycol (PG, 0-6wt%), kerosene (1wt%-6wt%), and oleic acid (OA, 1wt%-6wt%) with solvents (isopropyl alcohol (IPA), ethanol, and methanol). The results of reaction yield obtained from either magnetically or mechanically stirred systems were compared. Zinc borate produced was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and contact angle tests to identify the hydrophobicity. In conclusion, zinc borate is synthesized successfully under the optimized reaction conditions, and the different modifying agents with various solvents affect the hydrophobicity of zinc borate.

Acarali, Nil Baran; Bardakci, Melek; Tugrul, Nurcan; Derun, Emek Moroydor; Piskin, Sabriye

2013-06-01

144

Zinc oxide microcapsules obtained via a bio-inspired approach  

NASA Astrophysics Data System (ADS)

Hollow zinc oxide microcapsules have been synthesized by a sacrificial template route involving the chemical bath deposition of nanostructured zinc oxide thin films on sulfonate-modified polystyrene microspheres and subsequent removal of the polymer core by dissolution in a solvent or by thermolysis. Scanning electron micrographs show that uniform coating of the templates is achieved when ZnO is deposited from a solution containing zinc acetate, the polymer polyvinylpyrrolidone, and a base in methanol, and that the ZnO shells remain intact after removal of the cores. A focused ion beam is used to cut slices from the spheres and demonstrate their inner morphology and hollowness. X-ray diffraction yields evidence that the shells consist of nanocrystalline ZnO with the zincite structure.

Lipowsky, Peter; Hirscher, Michael; Hoffmann, Rudolf C.; Bill, Joachim; Aldinger, Fritz

2007-04-01

145

Photoexcited emission efficiencies of zinc oxide  

NASA Astrophysics Data System (ADS)

Optoelectronic properties of the II-VI semiconductor zinc oxide (ZnO) have been studied scientifically for almost 60 years; however, many fundamental questions remain unanswered about its two primary emission bands--the exciton-related luminescence in the ultraviolet and the defect-related emission band centered in the green portion of the visible spectrum. The work in this dissertation was motivated by the surprising optical properties of a ZnO nanowire sample grown by the group of Prof. Jie Liu, Department of Chemistry, Duke University. We found that this nanowire sample exhibited defect-related green/white emission of unprecedented intensity relative to near-band-edge luminescence. The experimental work comprising this dissertation was designed to explain the optical properties of this ZnO nanowire sample. Understanding the physics underlying such exceptional intensity of green emission addresses many of the open questions of ZnO research and assesses the possibility of using ZnO nanostructures as an ultraviolet-excited, broadband visible phosphor. The goal of this dissertation is to provide insight into what factors influence the radiative and nonradiative recombination efficiencies of ZnO by characterizing simultaneously the optical properties of the near-band-edge ultraviolet and the defect-related green emission bands. Specifically, we seek to understand the mechanisms of ultraviolet and green emission, the mechanism of energy transfer between them, and the evolution of their emission efficiencies with parameters such as excitation density and sample temperature. These fundamental but unanswered questions of ZnO emission are addressed here by using a novel combination of ultrafast spectroscopic techniques in conjunction with a systematic set of ZnO samples. Through this systematic investigation, ZnO may be realistically assessed as a potential green/white light phosphor. Photoluminescence techniques are used to characterize the thermal quenching behavior of both emission bands in micrometer-scale ZnO powders. Green luminescence quenching is described by activation energies associated with bound excitons. We find that green luminescence efficiency is maximized when excitons are localized in the vicinity of green-emitting defects. Subsequent photoluminescence excitation measurements performed at multiple temperatures independently verified that green band photoluminescence intensity directly correlates with the photogenerated exciton population. The spatial distributions of green-emitting defects and nonradiative traps are elucidated by an innovative combination of quantum efficiency and time-integrated/resolved photoluminescence measurements. By combining these techniques for the first time, we take advantage of the drastically different absorption coefficients for one- and two-photon excitations to provide details about the types and concentrations of surface and bulk defects and to demonstrate the non-negligible effects of reabsorption. A comparison of results for unannealed and annealed ZnO powders indicates that the annealing process creates a high density of green-emitting defects near the surface of the sample while simultaneously reducing the density of bulk nonradiative traps. These experimental results are discussed in the context of a simple rate equation model that accounts for the quantum efficiencies of both emission bands. For both femtosecond pulsed and continuous-wave excitations, the green band efficiency is found to decrease with increasing excitation density--from 35% to 5% for pulsed excitation spanning 1-1000 muJ/cm--2, and from 60% to 5% for continuous excitation in the range 0.01-10 W/cm --2. On the other hand, near-band-edge emission efficiency increases from 0.4% to 25% for increasing pulsed excitation density and from 0.1% to 0.6% for continuous excitation. It is shown experimentally that these changes in efficiency correspond to a reduction in exciton formation efficiency. The differences in efficiencies for pulsed versus continuous-wave excitation are described by changes in the relative

Foreman, John Vincent

146

Zinc oxide quantum dots synthesized by electrochemical etching of metallic zinc in organic electrolyte and their electrochemiluminescent properties  

Microsoft Academic Search

A universal and facile electrochemical etching method for synthesizing nanosized metal oxide semiconductors has been presented by taking the synthesis of ZnO quantum dots (QDs) from metallic zinc as an example. By applying an appropriate potential, metallic zinc was controllably oxidized to Zn2+ ion, the latter (Zn2+) was released into an organic electrolyte and hydrolyzed by trace dissolved water therein,

Lichan Chen; Nengna Xu; Haiyan Yang; Chen Zhou; Yuwu Chi

2011-01-01

147

Micropatterned zinc oxide nanowire substrate preparation and analysis  

Microsoft Academic Search

Zinc oxide (ZnO) nanowires offer a number of properties that are of interest in the field of neural tissue engineering. Materials that exhibit nanoscale surface dimensions have been shown to promote neuron function while simultaneously minimizing the activity of cells that inhibit central nervous system regeneration. Studies demonstrating enhanced neural tissue regeneration in electrical fields and on conductive scaffolds have

Justin T Seil; Diane Hoffman-Kim; Thomas J Webster

2007-01-01

148

Interfacial electron transfer dynamics of photosensitized zinc oxide nanoclusters  

SciTech Connect

The authors have prepared and characterized photosensitized zinc oxide (ZnO) nanoclusters, dispersed in methanol, using carboxylated coumarin dyes for surface adsorption. Femtosecond time-resolved emission spectroscopy allows the authors to measure the photo-induced charge carrier injection rate constant from the adsorbed photosensitizer to the n-type semiconductor nanocluster. These results are compared with other photosensitized semiconductors.

Murakoshi, Kei; Yanagida, Shozo [Osaka Univ. (Japan). Graduate School of Engineering; Capel, M. [Brookhaven National Lab., Upton, NY (United States)] [and others

1997-06-01

149

Anodic oxidation and self-polarization of zinc metal  

Microsoft Academic Search

X-ray diffraction techniques have been applied to study the structural changes and processes which take place when zinc metal is subjected to oxidation and self-polarization at the metal-electrolyte interface. The effect of electrolyte concentration and anodizing voltage on the structure and composition of the ZnO layer formed was investigated.

A. H. Abou El Ela; M. El Bahay; S. M. El-Raghy

1981-01-01

150

Process for fabricating doped zinc oxide microsphere gel  

DOEpatents

A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

Arnold, Jr., Wesley D. (Oak Ridge, TN); Bond, Walter D. (Knoxville, TN); Lauf, Robert J. (Oak Ridge, TN)

1991-01-01

151

Kinetics of fluoride release from zinc oxide-based cements  

Microsoft Academic Search

Considerable attention has been given to the release of the cariostatic fluoride ion from glass-based dental cements (dental silicate and glass ionomer). In these, the total available fluoride content is not precisely known since fluorine is distributed between the cross-linked aqueous salt matrix, partially dissolved glass, and undissolved glass. In analogous cements based on zinc oxide the fluoride is added

R. W. Billington; P. C. Hadley; J. A. Williams; G. J. Pearson

2001-01-01

152

Electron Spin Resonance Study of Hydroperoxide on Zinc Oxide.  

National Technical Information Service (NTIS)

The esr signal observed on zinc oxide (g 1.961) following oxygen treatment at 500C decreases in intensity on exposing the degassed sample to t-butyl hydroperoxide (TBHP) vapors. However, with samples vacuum-outgassed at 500C, the absorption of TBHP leads ...

M. Codell H. Gisser J. Weisberg R. D. Iyengar

1967-01-01

153

Preparation and characterization of lead doped zinc oxide thin films  

NASA Astrophysics Data System (ADS)

Undoped and Lead doped Zinc Oxide thin films were prepared by low-cost Spray pyrolysis technique. XRD and UV-Vis spectroscopy techniques were employed for characterizing the films, as the doping is increased the change in structural properties and optical transmittance is noted.

Valan, I. Inigo; Gokulakrishnan, V.; Stephen, A.; Ramamurthi, K.

2013-02-01

154

Hydrogen sensors based on zinc oxide nanoparticles  

Microsoft Academic Search

Pure ZnO, pure MgO and 5 wt%MgO\\/ZnO nanocomposites were produced by flame spray pyrolysis (FSP) in a single step using zinc naphthenate and magnesium acetate tetrahydrate as Zn and Mg precursors. The particle properties were analyzed by XRD, BET and TEM analyses. The sensing films were prepared by mixing the nanoparticles into an organic paste composed of ethyl cellulose and

Thanittha Samerjai; C. Liewhiran; A. Wisitsoraat; Sukon Phanichphant

2010-01-01

155

Oxidative modification of guanine bases initiated by oxyl radicals derived from photolysis of azo compounds.  

PubMed

Oxidative damage to guanine bases initiated by photolysis of the water-soluble radical generator 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) has been investigated by laser kinetic spectroscopy. In the neutral oxygenated aqueous solutions, 355 nm laser flash photolysis of AAPH generates a whole spectrum of free radicals including 2-amidinoprop-2-peroxyl (ROO(*)), 2-amidinoprop-2-oxyl (RO(*)), and superoxide (O(2)(*-)) radicals. These oxyl radicals with negligible absorption in a near UV-visible range were monitored in the reactions leading to the products with characteristic absorption spectra. This approach reveals that RO(*) radicals induce fast one-electron oxidation of 2'-deoxyguanosine (dG) to form guanine neutral radicals, dG(-H)(*). In contrast, ROO(*) radicals do not react at observable rates with dG. The O(2)(*-) radicals were detected using a classical test reaction with tetranitromethane to form nitroform. The major pathway for formation of the end-products of guanine oxidation is the combination of the G(-H)(*) and O(2)(*-) radicals to form 2,5-diamino-4H-imidazolone (Iz). This mechanism was confirmed by analysis of the end-products produced by oxidation of two substrates: (1) the guanosine derivative 2',3',5'-tri-O-acetylguanosine (tri-O-Ac-G) and (2) the 5'-d(CCATCGCTACC) sequence. The major products isolated by HPLC and identified by mass spectrometry methods were the tri-O-Ac-Iz and 5'-d(CCATC[Iz]CTACC products. PMID:20415485

Shao, Jie; Geacintov, Nicholas E; Shafirovich, Vladimir

2010-05-20

156

Electrodeposited zinc oxide thin films: Nucleation and growth mechanism  

Microsoft Academic Search

The nucleation and growth mechanism of the electrodeposited zinc oxide thin films on fluorine-doped tin oxide (FTO) coated (10–20?\\/cm2) glass substrates from acetate solution, without and with ex situ oxygen bubbling, has been studied by cyclic voltammetry (CV), chronoamperometry (CA) and scanning electron microscopy (SEM) techniques. Ethylene diamine tetra acetic acid (EDTA) was used as a complexing agent. The cyclic

A. I. Inamdar; S. H. Mujawar; S. B. Sadale; A. C. Sonavane; M. B. Shelar; P. S. Shinde; P. S. Patil

2007-01-01

157

Nearly full-dense and fine-grained AZO:Y ceramics sintered from the corresponding nanoparticles.  

PubMed

Aluminum-doped zinc oxide ceramics with yttria doping (AZO:Y) ranging from 0 to 0.2 wt.% were fabricated by pressureless sintering yttria-modified nanoparticles in air at 1,300°C. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis, a physical property measurement system, and a densimeter were employed to characterize the precursor nanoparticles and the sintered AZO ceramics. It was shown that a small amount of yttria doping can remarkably retard the growth of the as-received precursor nanoparticles, further improve the microstructure, refine the grain size, and enhance the density for the sintered ceramic. Increasing the yttria doping to 0.2 wt.%, the AZO:Y nanoparticles synthetized by a coprecipitation process have a nearly sphere-shaped morphology and a mean particle diameter of 15.1 nm. Using the same amount of yttria, a fully dense AZO ceramic (99.98% of theoretical density) with a grain size of 2.2 ?m and a bulk resistivity of 4.6?×?10-3??·cm can be achieved. This kind of AZO:Y ceramic has a potential to be used as a high-quality sputtering target to deposit ZnO-based transparent conductive films with better optical and electrical properties. PMID:22929049

Yang, Ye; Lan, Pinjun; Wang, Muqin; Wei, Tiefeng; Tan, Ruiqin; Song, Weijie

2012-08-29

158

Tensile strain and water vapor transport testing of flexible, conductive and transparent indium–zinc-oxide\\/silver\\/indium–zinc-oxide thin films  

Microsoft Academic Search

Thin film laminates composed of sputtered indium zinc oxide and silver, optimized for conductance and transparency, were tested for water vapor permeation as well as mechanical durability in tension. The ~82nm thick optimized indium–zinc-oxide\\/silver\\/indium–zinc-oxide (IZO\\/Ag\\/IZO) films were >80% transparent in the visible range (400nm–700nm) with measured sheet resistances less than 5?\\/sq. The water vapor permeation measurements using Ca test methods

Arrelaine A. Dameron; David C. Miller; Nathan George; Bobby To; David S. Ginley; Lin Simpson

2011-01-01

159

Octadecanethiol Island Formation on Single Crystal Zinc Oxide Surfaces  

NASA Astrophysics Data System (ADS)

Organic photovoltaic devices, comprised of zinc oxide (ZnO) nanorod electron acceptor arrays intercalated with organic polymers, could lead to low-cost renewable energy generation. Surface modifications of ZnO with octadecanethiol (ODT) monolayers can help to improve charge transfer in such devices. In the present work, single crystals of ZnO provided well-defined oxygen-terminated and zinc-terminated surfaces on which to learn fundamentally about the attachment and growth of ODT. Both bare zinc oxide and ODT-functionalized surfaces were characterized with atomic force microscopy, Fourier transform infrared spectroscopy, x-ray photoemission spectroscopy, and contact angle analysis. ODT seemed to form islands of multilayers on zinc-terminated surfaces, while it formed islands of monolayers on oxygen-terminated surfaces. While ODT was expected to preferentially bond along defects and terraces on oxygen-terminated surfaces, this was not observed. ODT was also expected to more effectively bond to the zinc-terminated surface, which was observed. Finally, surface preparation treatments designed to leave atomically-flat oxygen terminated surfaces were developed. This work was made possible by the National Science Foundation Division of Materials Research and the Renewable Energy Materials Research Science and Engineering Center at the Colorado School of Mines.

Yocom, Andrea

2009-10-01

160

Epitaxial Growth of Zinc Oxide on Single Crystalline Gold Plates  

NASA Astrophysics Data System (ADS)

Although metal-oxide interfaces are the critical components of many electronic and optical devices, it is rare to find epitaxial metal-oxide structures. We demonstrate for the first time, a method for the low temperature, epitaxial growth of zinc oxide (ZnO) on single crystalline gold plates. The gold plates, up to 100?m in width, are grown from a gold-surfactant complex. Even with the large lattice mismatch between (111) gold and (0001) ZnO, we are able to form epitaxial zinc oxide at 90^oC on top of the single crystal gold plates. This epitaxial growth is confirmed using transmission electron microscopy, electron diffraction, and electron backscatterer diffraction. Micro-photoluminescence is also performed to investigate the optical properties of the epitaxial zinc oxide. We remove the grown ZnO membranes from the gold plates using a stamping and etching process. These membranes can potentially be used to fabricate high quality microdisks and photonic crystals. The metal-oxide interfaces that we have fabricated may have the ability to be used in a number of technologically important applications, including as better electrical contacts and for improved light extraction from planar LED structures.

Greenberg, Kathryn; Joo, John; Baram, Mor; Clarke, David; Hu, Evelyn

2012-02-01

161

Degradation of azo dye Procion Red MX5B by photocatalytic oxidation  

Microsoft Academic Search

The photocatalytic oxidation (PCO) of a monoazo dye Procion Red MX-5B under various physico-chemical conditions was investigated. Degradation of the dye by PCO was enhanced by augmentation in UV intensity, titanium dioxide and hydrogen peroxide concentrations but was inhibited by increase in initial dye concentration. The PCO process was affected by pH in a peculiar way. In the presence of

C. M So; M. Y Cheng; J. C Yu; P. K Wong

2002-01-01

162

Zinc self-diffusion, electrical properties, and defect structure of undoped, single crystal zinc oxide  

SciTech Connect

Zinc self-diffusion was measured in single crystal zinc oxide using nonradioactive {sup 70}Zn as the tracer isotope and secondary ion mass spectrometry for data collection. Crystal mass was closely monitored to measure ZnO evaporation. Diffusion coefficients were isotropic with an activation energy of 372 kJ/mol. Zinc self-diffusion is most likely controlled by a vacancy mechanism. Electrical property measurements exhibit a plateau in conductivity at intermediate pO{sub 2} with an increase in reducing atmospheres. An analysis of the defect structure is presented that indicates that oxygen vacancies are probably the intrinsic ionic defects responsible for n-type conductivity in reducing atmospheres. (c) 2000 American Institute of Physics.

Tomlins, Gregory W. [Energy Technology Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Routbort, Jules L. [Energy Technology Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Mason, Thomas O. [Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States)

2000-01-01

163

Structure control of sputtered zinc oxide films by utilizing zinc oxide seed layers tailored by ion beam assisted sputtering  

Microsoft Academic Search

Reactively sputtered zinc oxide thin films typically exhibit a c-oriented (0 0 0 1) texture of low crystalline order when deposited on unheated substrates. The structural order can be significantly improved upon heating the substrates during deposition. Here it will be demonstrated that by utilizing c-textured seed layers, which are grown by an ion beam assisted sputtering (IBAS) process, films

Dominik Köhl; Gomathi Natarajan; Matthias Wuttig

2012-01-01

164

Organic solar cells on indium tin oxide and aluminum doped zinc oxide anodes  

Microsoft Academic Search

The authors compare organic solar cells using two different transparent conductive oxides as anode: indium tin oxide (ITO) and three kinds of aluminum doped zinc oxide (ZAO). These anodes with different work functions are used for small molecule photovoltaic devices based on an oligothiophene derivative as donor and fullerene C60 as acceptor molecule. It turns out that cells on ITO

Kerstin Schulze; Bert Maennig; Karl Leo; Yuto Tomita; Christian May; Jürgen Hüpkes; Eduard Brier; Egon Reinold; Peter Bäuerle

2007-01-01

165

Indium recovery from zinc oxide flue dust by oxidative pressure leaching  

Microsoft Academic Search

Indium was recovered from zinc oxide flue dust (ZOFD) with sulfuric acid by oxidative pressure leaching in an autoclave, and the effects of different technological conditions on indium leaching were studied. Potassium permanganate and hydrogen peroxide were used as oxidants. The atmospheric pressure leaching experiments were also carried out. The experimental results show that the leaching rate of indium can

Xuan-hai LI; Yan-juan ZHANG; Quan-lun QIN; Jian YANG; Yan-song WEI

2010-01-01

166

Decolorization of the azo dye Reactive Black 5 by Fenton and photo-Fenton oxidation  

Microsoft Academic Search

The oxidative decolorization of Reactive Black 5 (RB5) in aqueous solution has been studied using Fenton (H2O2\\/Fe2+) and photo-Fenton (H2O2\\/Fe2+\\/UV) processes. This investigation reveals that both methods can remove the color of RB5. Batch experiments were carried out to investigate the process's optimal operational conditions: pH, H2O2 dosage, Fe2+ dosage, RB5 concentration and optimal [Fe2+]0\\/[H2O2]0\\/[RB5]0 ratio, to obtain the bests

Marco S. Lucas; José A. Peres

2006-01-01

167

Zinc oxide nanowires for biosensor applications  

NASA Astrophysics Data System (ADS)

The current paper is devoted to the fabrication and optimisation of ZnO nanowire (ZnONW) arrays for electrochemical glucose biosensor fabrication. The ZnO nanowires were fabricated by a two-step combination method. This includes radio-frequency (RF) sputtering of the ZnO seeding layer and hydrothermal growth of the nanowires in a solution containing zinc nitrate hexahydrate. Glucose oxidase has been immobilised on the nanowires, for use as the biorecognition molecule. The sensing characteristics of the biosensors based on this fabrication methodology were investigated in phosphate buffer solution using electrochemical techniques.

Gabrielyan, Nare; Paul, Shashi

2011-07-01

168

Improved transparent conducting oxides through modulation-doped zinc oxide\\/zinc magnesium oxide thin films  

Microsoft Academic Search

ZnO is a member of the unique class of materials known as transparent conducting oxides (TCOs). TCOs are currently used for many applications including flat panel displays, solar cells, and energy efficient windows. Of particular interest is the possibility of developing materials that have high electron mobilities, such that conductivities may be increased without loosing transparency in the visible spectrum.

David J. Cohen

2008-01-01

169

Azo dye removal in a membrane-free up-flow biocatalyzed electrolysis reactor coupled with an aerobic bio-contact oxidation reactor.  

PubMed

Azo dyes that consist of a large quantity of dye wastewater are toxic and persistent to biodegradation, while they should be removed before being discharged to water body. In this study, Alizarin Yellow R (AYR) as a model azo dye was decolorized in a combined bio-system of membrane-free, continuous up-flow bio-catalyzed electrolysis reactor (UBER) and subsequent aerobic bio-contact oxidation reactor (ABOR). With the supply of external power source 0.5 V in the UBER, AYR decolorization efficiency increased up to 94.8±1.5%. Products formation efficiencies of p-phenylenediamine (PPD) and 5-aminosalicylic acid (5-ASA) were above 90% and 60%, respectively. Electron recovery efficiency based on AYR removal in cathode zone was nearly 100% at HRTs longer than 6 h. Relatively high concentration of AYR accumulated at higher AYR loading rates (>780 gm(-3) d(-1)) likely inhibited acetate oxidation of anode-respiring bacteria on the anode, which decreased current density in the UBER; optimal AYR loading rate for the UBER was 680 gm(-3) d(-1) (HRT 2.5 h). The subsequent ABOR further improved effluent quality. Overall the Chroma decreased from 320 times to 80 times in the combined bio-system to meet the textile wastewater discharge standard II in China. PMID:23009797

Cui, Dan; Guo, Yu-Qi; Cheng, Hao-Yi; Liang, Bin; Kong, Fan-Ying; Lee, Hyung-Sool; Wang, Ai-Jie

2012-09-04

170

Zinc recovery from sphalerite concentrate by direct oxidative leaching with ammonium, sodium and potassium persulphates  

Microsoft Academic Search

The recovery of zinc from sphalerite concentrate by oxidative leaching with ammonium, sodium and potassium persulphates in sulphuric acid media is reported in this investigation. Effects of particle size, reaction temperature, acid concentration, pulp density (PD) and oxidant concentration on zinc dissolution rate were determined. The results showed that leaching of 95% zinc was achieved from the concentrate of particle

M. N. Babu; K. K. Sahu; B. D. Pandey

2002-01-01

171

Nanocrystalline zinc oxide thin films by novel double pulse single step electrodeposition  

Microsoft Academic Search

An attempt has been made to fabricate nanocrystalline zinc oxide thin films by using double pulse potentiostatic electrodeposition in oxygen saturated zinc acetate bath onto FTO coated conducting glass substrates. Zinc oxide formation mechanism has been studied by using linear sweep voltammetry (LSV) and electrochemical quartz crystal microbalance (EQCM) in presence of oxygen. The influence of pulse parameters like nucleation

A. I. Inamdar; A. C. Sonavane; S. K. Sharma; Hyunsik Im; P. S. Patil

2010-01-01

172

Zinc impregnation of the anodic oxidation layer of 1050 and 2024 aluminium alloys  

Microsoft Academic Search

The porous oxide layer obtained by phosphoric anodic oxidation (PAO) of 1050 and 2024T3 aluminium alloys is modified by impregnation with zinc under alternating voltage. The resulting current against applied voltage relationship shows that a threshold voltage is required to deposit the zinc. Beyond a low critical voltage, VcL, zinc electrocrystallization starts near the barrier layer and grows with time

J. P. Dasquet; J. P. Bonino; D. Caillard; R. S. Bes

2000-01-01

173

Polyurethane–zinc borate composites with high oxidative stability and flame retardancy  

Microsoft Academic Search

Novel polyurethane zinc borate composites were prepared with the main aim to increase the flame retardancy of the polyurethane. It was discovered that the zinc borate had very significant effects on the oxidative stability of the neat polymer which was first observed by oxygen induction time tests and supported with actual weathering chamber tests. The oxidative stability of zinc borate-filled

Basar Y?ld?z; M. Özgür Seydibeyo?lu; F. Seniha Güner

2009-01-01

174

Marginal zinc deficiency increases oxidative DNA damage in the prostate after chronic exercise  

Microsoft Academic Search

Approximately 12% of Americans do not consume the recommended level of zinc and could be at risk for marginal zinc deficiency. Zinc functions in antioxidant defense and DNA repair and could be important for prostate health. We hypothesized that marginal zinc deficiency sensitizes the prostate to oxidative stress and DNA damage. Rats were fed a zinc-adequate (ZA; 30 mg Zn\\/kg) or

Yang Song; Valerie Elias; Andrei Loban; Angus G. Scrimgeour; Emily Ho

2010-01-01

175

Scale-up synthesis of zinc borate from the reaction of zinc oxide and boric acid in aqueous medium  

Microsoft Academic Search

Synthesis of zinc borate was conducted in a laboratory and a pilot scale batch reactor to see the influence of process variables on the reaction parameters and the final product, 2ZnO·3B2O3·3.5H2O. Effects of stirring speed, presence of baffles, amount of seed, particle size and purity of zinc oxide, and mole ratio of H3BO3:ZnO on the zinc borate formation reaction were

Mert Kilinç; Gaye Ö. Çakal; Sertan Yesil; Göknur Bayram; Inci Eroglu; Saim Özkar

2010-01-01

176

Supermicroporous alumina?silica zinc oxides  

SciTech Connect

A new family of porous mixed oxides with pores largely in the 8-20 {angstrom} range have been prepared. TEOS acts as a solvent and as a source of silica to which aluminum butoxide and transition metal acetates are added. Neutral amines are added as templates and to effect hydrolysis. This paper describes the ZnO-Al{sub 2}O{sub 5}-SiO{sub 2} system but similar results have been obtained with other transition metal oxides. An interesting feature of the technique is that the larger the amine template the greater is the surface area of the mixed oxide with only a slight increase in the average pore diameter. Both NMR and atomic pair distribution functional methods have been used to prove the homogeneity of the mixed oxide products. This preparative method complements our earlier report in Chemical Communications on mixed oxides prepared with ZrO{sub 2} and TiO{sub 2} incorporating transition metal oxides.

Shpeizer, Boris G.; Bakhmutov, Vladimir I.; Clearfield, Abraham (TAM)

2008-09-29

177

Ozonation of an azo dye C.I. Remazol Black 5 and toxicological assessment of its oxidation products  

Microsoft Academic Search

The effect of ozonation (20.5 mgl?1) on the degradation processes of an azo dye, Remazol Black 5 (RB5; CI) was studied. Conventional parameters such as chemical oxygen demand (COD), total organic carbon (TOC), pH, conductivity, colour removal, biodegradability (BOD5\\/28), and toxic potential of the dye and its degradation products were monitored during the process. The results obtained indicated that ozonation

Chunxia Wang; Ayfer Yediler; Doris Lienert; Zijian Wang; Antonius Kettrup

2003-01-01

178

The Effect of High Pressure on the Voltage and Current Output of Silver Oxide-Zinc and Mercury Oxide-Zinc Miniature Batteries.  

National Technical Information Service (NTIS)

The open circuit voltage (emf) and the voltage under load of alkaline silver-oxide-zinc and mercuric oxide-zinc miniature batteries have been measured at pressures up to 20 kbars. The emf of these batteries varies with pressure in the manner expected base...

T. N. Andersen B. A. Miner M. H. Ghandehari R. J. Brodd H. Eyring

1969-01-01

179

Solvothermal routes for synthesis of zinc oxide nanorods.  

SciTech Connect

Control of the synthesis of nanomaterials to produce morphologies exhibiting quantized properties will enable device integration of several novel applications including biosensors, catalysis, and optical devices. In this work, solvothermal routes to produce zinc oxide nanorods are explored. Much previous work has relied on the addition of growth directing/inhibiting agents to control morphology. It was found in coarsening studies that zinc oxide nanodots will ripen to nanorod morphologies at temperatures of 90 to 120 C. The resulting nanorods have widths of 9-12 nm average dimension, which is smaller than current methods for nanorod synthesis. Use of nanodots as nuclei may be an approach that will allow for controlled growth of higher aspect ratio nanorods.

Bell, Nelson Simmons

2005-03-01

180

Combinatorial study of zinc tin oxide thin-film transistors  

SciTech Connect

Groups of thin-film transistors using a zinc tin oxide semiconductor layer have been fabricated via a combinatorial rf sputtering technique. The ZnO:SnO{sub 2} ratio of the film varies as a function of position on the sample, from pure ZnO to SnO{sub 2}, allowing for a study of zinc tin oxide transistor performance as a function of channel stoichiometry. The devices were found to have mobilities ranging from 2 to 12 cm{sup 2}/V s, with two peaks in mobility in devices at ZnO fractions of 0.80{+-}0.03 and 0.25{+-}0.05, and on/off ratios as high as 10{sup 7}. Transistors composed predominantly of SnO{sub 2} were found to exhibit light sensitivity which affected both the on/off ratios and threshold voltages of these devices.

McDowell, M. G.; Sanderson, R. J.; Hill, I. G. [Dalhousie University, Department of Physics, Halifax, Nova Scotia B3H 3J5 (Canada)

2008-01-07

181

Zinc ion and neutral emission from single crystal zinc oxide during 193-nm excimer laser exposure  

SciTech Connect

Mass resolved time-of-flight measurements on neutral zinc atoms and zinc ions show energetic ions and neutrals during 193-nm irradiation of single crystals of semiconducting zinc oxide. Typical Zn+ kinetic energies are 3-5 eV. At fluences (energy per unit area per pulse) below 200 mJ/cm2, the ion intensities (per laser pulse) decrease monotonically to low values with laser pulse number. The depletion kinetics change from exponential to second order near 50 mJ/cm2. We attribute this change to the annihilation of defects yielding Zn+ emission when Zn+ or other surface defects become mobile. At fluences between 200 and 300 mJ/cm2, Zn+ emission becomes more sustained due to defects created by the laser. In this same fluence range, we observe the onset of detectable neutral atomic zinc emission. These neutral atoms display Maxwell-Boltzmann kinetic energy distributions w th effective surface temperatures that approach 5000 K as the fluence is raised to 350 mJ/cm2. These high surface temperatures are remarkable given the low etch rates observed at these fluences, suggesting that heated layer is extremely thin. We propose emission mechanisms and experiments to resolve outstanding questions.

Kahn, E. H. [Washington State University; Langford, S. C. [Washington State University; Boatner, Lynn A [ORNL; Dickinson, J. T. [Washington State University

2011-01-01

182

Electron Paramagnetic Resonance of V3+ Ions in Zinc Oxide  

Microsoft Academic Search

The paramagnetic resonance of trace amounts of V3+ in single-crystal hexagonal zinc oxide is reported. The EPR spectrum is fitted with an axially symmetric spin Hamiltonian with five empirically determined parameters: D, gII, g?, A, and B. The spin-Hamiltonian parameters are interpreted in terms of the Racâh parameter B, the crystal-field parameters Dq, Ds, Dt, and the spin-orbit coupling constant

G. Filipovich; A. L. Taylor; R. E. Coffman

1970-01-01

183

Improved zinc oxide film for gas sensor applications  

Microsoft Academic Search

Zinc oxide (ZnO) is a versatile material for different commercial applications such as transparent electrodes, piezoelectric\\u000a devices, varistors, SAW devices etc because of its high piezoelectric coupling, greater stability of its hexagonal phase and\\u000a its pyroelectric property. In fact, ZnO is a potential material for gas sensor applications. Good quality ZnO films were deposited\\u000a on glass and quartz substrates by

S. Roy; S. Basu

2002-01-01

184

Crystalline state and acoustic properties of zinc oxide films  

Microsoft Academic Search

We study the effect of the crystalline state of zinc oxide films, prepared by magnetron sputtering, on the efficiency of SAW transducers based on the layered system textured ZnO film-interdigital transducer (IDT)-fused quartz substrate. The crystalline perfection of the ZnO films was studied by the x-ray method using a DRON-2.0 diffractometer. The acoustic properties of the layered system fused quartz

G. I. Kalnaya; I. F. Pryadko; Yu. A. Yarovoi

1988-01-01

185

Anodic oxidation and self-polarization of zinc metal  

Microsoft Academic Search

X-ray diffraction techniques have been applied to study the structural changes and processes which take place when zinc metal\\u000a is subjected to oxidation and self-polarization at the metal-electrolyte interface. The effect of electrolyte concentration\\u000a and anodizing voltage on the structure and composition of the ZnO layer formed was investigated.

A. H. Abou El Ela; M. El Bahay; S. M. El-Raghy

1981-01-01

186

TOPICAL REVIEW: Zinc oxide nanostructures: growth, properties and applications  

Microsoft Academic Search

Zinc oxide is a unique material that exhibits semiconducting and piezoelectric dual properties. Using a solid-vapour phase thermal sublimation technique, nanocombs, nanorings, nanohelixes\\/nanosprings, nanobelts, nanowires and nanocages of ZnO have been synthesized under specific growth conditions. These unique nanostructures unambiguously demonstrate that ZnO probably has the richest family of nanostructures among all materials, both in structures and in properties. The

Zhong Lin Wang

2004-01-01

187

Electrochemical Deposition of Conductive Superhydrophobic Zinc Oxide Thin Films  

Microsoft Academic Search

A simple method of electrochemical deposition was adopted to prepare conductive hydrophobic zinc oxide (ZnO) thin films. The surface structures were characterized by sanning electron microscopy (SEM) and atomic force microscopy (AFM). Wettability studies revealed that the surface of the as-prepared thin films showed a contact angle (CA) for water of 128.3 ( 1.7°, whereas the superhydrophobic surface with a

Mei Li; Jin Zhai; Huan Liu; Yanlin Song; Lei Jiang; Daoben Zhu

2003-01-01

188

Growth and Process Induced Dislocations in Zinc Oxide Crystals  

SciTech Connect

Zinc oxide crystals were grown using hydrothermal method, and the habit faces were indexed by computing from inter-axial angles of the as grown boules. The dislocation structures were studied using synchrotron white beam X-ray topography. Grown-in dislocations as well as process-induced defects were characterized in the ZnO crystals. Knoop and Vickers micro-hardness were studied on sliced crystal plates. Chemical etching was used to study the dislocations running perpendicular to the wafer.

Dhanaraj,G.; Dudley, M.; Bliss, D.; Callahan, M.; Harris, M.

2006-01-01

189

Zinc-oxide-based sorbents and processes for preparing and using same  

DOEpatents

Zinc oxide-based sorbents, and processes for preparing and using them are provided. The sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents comprise an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, comprising a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

Gangwal, Santosh Kumar (Cary, NC); Turk, Brian Scott (Durham, NC); Gupta, Raghubir Prasael (Durham, NC)

2010-03-23

190

Nanocrystalline zinc oxide for the decontamination of sarin.  

PubMed

Nanocrystalline zinc oxide materials were prepared by sol-gel method and were characterized by X-ray diffraction, scanning electron microscopy, thermogravimetry, nitrogen adsorption and infrared spectroscopy techniques. The data confirmed the formation of zinc oxide materials of zincite phase with an average crystallite size of approximately 55 nm. Obtained material was tested as destructive adsorbent for the decontamination of sarin and the reaction was followed by GC-NPD and GC-MS techniques. The reaction products were characterized by GC-MS and the data explored the role of hydrolysis reaction in the detoxification of sarin. Sarin was hydrolyzed to form surface bound non-toxic phosphonate on the surface of nano-zinc oxide. The data also revealed the values of rate constant and half-life to be 4.12h(-1) and 0.16 h in the initial stages of the reaction and 0.361 h(-1) and 1.9h at the final stages of the reaction for the decontamination reaction on nanocrystalline ZnO. PMID:19121895

Mahato, T H; Prasad, G K; Singh, Beer; Acharya, J; Srivastava, A R; Vijayaraghavan, R

2008-11-11

191

Induction of nitric oxide-dependent apoptosis in motor neurons by zinc-deficient superoxide dismutase.  

PubMed

Mutations in copper, zinc superoxide dismutase (SOD) have been implicated in the selective death of motor neurons in 2 percent of amyotrophic lateral sclerosis (ALS) patients. The loss of zinc from either wild-type or ALS-mutant SODs was sufficient to induce apoptosis in cultured motor neurons. Toxicity required that copper be bound to SOD and depended on endogenous production of nitric oxide. When replete with zinc, neither ALS-mutant nor wild-type copper, zinc SODs were toxic, and both protected motor neurons from trophic factor withdrawal. Thus, zinc-deficient SOD may participate in both sporadic and familial ALS by an oxidative mechanism involving nitric oxide. PMID:10617463

Estévez, A G; Crow, J P; Sampson, J B; Reiter, C; Zhuang, Y; Richardson, G J; Tarpey, M M; Barbeito, L; Beckman, J S

1999-12-24

192

MOCVD-growth of thin zinc oxide films from zinc acetylacetonate and air  

NASA Astrophysics Data System (ADS)

The metalorganic chemical vapour deposition (MOCVD) of thin zinc oxide films on borosilicate glass and silicon substrates in a hot-wall CVD-reactor (HWR) was studied. Zinc acetylacetonate (Zn(acac)2) and air were used as precursors. The aim of this work was to optimize the deposition parameters, such as pressure and deposition temperature, with respect to the film quality, structure, and homogeneity. Most experiments were performed at atmospheric pressure; this approach avoids the usage of an expensive vacuum system. It turned out that polycrystalline zinc oxide is grown at deposition temperatures above 613 K. Above 823 K, they additionally are c-axis orientated. At atmospheric pressure and lower temperature (<773 K) the film deposition is homogeneously over the whole tube furnace while at higher temperature inhomogeneous film growth and particle formation are observed, indicating a shift of the growth mechanism to the diffusion controlled regime. Although the homogeneity is improved by using higher flow velocities at atmospheric pressure, particle growth cannot be suppressed. Only at reduced pressure, which was 200 mbar in the present case, the deposition at 823 K is kinetically controlled and without particle formation, resulting in the homogeneous growth of well adhering ZnO films with c-axis orientation.

Pflitsch, Christian; Nebatti, Abdelkader; Brors, Georg; Atakan, Burak

2012-06-01

193

Durable zinc oxide-containing sorbents for coal gas desulfurization  

DOEpatents

Durable zinc-oxide containing sorbent pellets for removing hydrogen sulfide from a gas stream at an elevated temperature are made up to contain titania as a diluent, high-surface-area silica gel as a matrix material, and a binder. These materials are mixed, moistened, and formed into pellets, which are then dried and calcined. The resulting pellets undergo repeated cycles of sulfidation and regeneration without loss of reactivity and without mechanical degradation. Regeneration of the pellets is carried out by contacting the bed with an oxidizing gas mixture.

Siriwardane, R.V.

1994-12-31

194

Durable zinc oxide-containing sorbents for coal gas desulfurization  

DOEpatents

Durable zinc-oxide containing sorbent pellets for removing hydrogen sulfide from a gas stream at an elevated temperature are made up to contain titania as a diluent, high-surface-area silica gel, and a binder. These materials are mixed, moistened, and formed into pellets, which are then dried and calcined. The resulting pellets undergo repeated cycles of sulfidation and regeneration without loss of reactivity and without mechanical degradation. Regeneration of the pellets is carried out by contacting the bed with an oxidizing gas mixture.

Siriwardane, Ranjani V. (Morgantown, WV)

1996-01-01

195

Excimer laser interaction with zinc oxide  

NASA Astrophysics Data System (ADS)

When single crystal ZnO is exposed to 193-nm laser photons in vacuum at fluences below 100 mJ/cm2, isolated Zn vacancies are produced due to the emission of energetic Zn+. The pair wise formation of Zn vacancies and Zn+ interstitials is attributed to the photochemical excitation of anti-bonding Zn-O bonds. Interstitial Zn + diffuses to the surface where it is loosely bound to the surface---often atop a photoionizable electron trap; adsorbed Zn+ is emitted when the underlying trap is photoionized. Isolated Zn vacancies also diffuse following the laser pulse. These electron traps can reduce the near-surface free carrier concentration by as much as a factor of five on irradiated samples. At fluences between 150 and 200 mJ/cm2, 193-nm irradiation produces sustained emission of ionic and neutral species. The near-surface region of the irradiated sample becomes increasingly metallic and zinc rich. At fluences in the 250--300 mJ/cm2 range, a slower component of the Zn+ emission appears which is attributed to the excitation of an auto-ionizing state at 12.77 eV. The same excitation also yields Zn atomic light emission, predominately due to transitions on the triplet manifold. Rydberg Zn* atoms in high-lying quantum states appear at a threshold fluence of about 350 mJ/cm2. At fluences greater than or equal to 2 J/cm2, atomic light emission due to optical breakdown is observed.

Khan, Enamul Haque

196

The Transistor Characteristics of Zinc Oxide Active Layer with Different Thickness of Zinc Oxide Thin-Film  

Microsoft Academic Search

ZnO is a wide band gap semiconductor which is used as transparent electrode in solar cells, chemical and gas sensors and light emitting diodes etc. This study examines the semiconductor layers produced by ZnO solution with sol-gel method and spin-coating in zinc oxide (ZnO) thin-film transistors (TFTs). By using spin coating method, the films are deposited on Si substrates. Compared

Hsin-Chiang You; Yen-Wei Tu; Yu-Hsien Lin; Shao-Hui Shieh

2012-01-01

197

Nonohmic Properties of Zinc Oxide Ceramics  

Microsoft Academic Search

Nonohmic properties of ZnO ceramics with five additives of Bi2O3, CoO, MnO, Cr2O3, and Sb2O3 are studied in relation to sintering temperature, additive content, and temperature dependence. The observation of electron photomicrographs and X-ray microanalysis proves a ceramic microstructure such that ZnO and these five oxides form, at the grain boundaries, segregation layers which are responsible for the nonohmic properties.

Michio Matsuoka

1971-01-01

198

A biomimetic approach towards synthesis of zinc oxide nanoparticles.  

PubMed

Using natural processes as inspiration, the present study demonstrates a positive correlation between zinc metal tolerance ability of a soil fungus and its potential for the synthesis of zinc oxide (ZnO) nanoparticles. A total of 19 fungal cultures were isolated from the rhizospheric soils of plants naturally growing at a zinc mine area in India and identified on the genus, respectively the species level. Aspergillus aeneus isolate NJP12 has been shown to have a high zinc metal tolerance ability and a potential for extracellular synthesis of ZnO nanoparticles under ambient conditions. UV-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis, transmission electron microscopy, and energy dispersive spectroscopy studies further confirmed the crystallinity, morphology, and composition of synthesized ZnO nanoparticles. The results revealed the synthesis of spherical nanoparticles coated with protein molecules which served as stabilizing agents. Investigations on the role of fungal extracellular proteins in the synthesis of nanoparticles indicated that the process is nonenzymatic but involves amino acids present in the protein chains. PMID:22382164

Jain, Navin; Bhargava, Arpit; Tarafdar, Jagadish C; Singh, Sunil K; Panwar, Jitendra

2012-03-01

199

Fabrication of zinc oxide, titanium oxide, and organic-entrapped-silica thin films via laser-assisted molecular beam deposition  

Microsoft Academic Search

Thin films of zinc oxide, titanium oxide and nonlinear optical organic chromophores entrapped silica were all fabricated by using a new technique called laser assisted molecular beam deposition (LAMBD). In the cases of the zinc and titanium oxides, molecular oxygen was supersonically expanded into the laser ablated plasma plume of pure metallic targets and then directed towards a substrate. In

W. M. Wijekoon; Paras N. Prasad; James F. Garvey

1995-01-01

200

Zinc oxide thin films deposited by magnetron sputtering with various oxygen\\/argon concentrations  

Microsoft Academic Search

Deposition of zinc oxide thin films onto silicon and thermally oxidized silicon substrates was performed by radio frequency magnetron sputtering. The obtained films were studied in function of percentage of oxygen and argon flow as process gases. Stoichiometric films were obtained in oxygen rich process conditions, which are more suitable to be p-type doped. Growth of zinc oxide films over

L R Damiani; R D Mansano

2012-01-01

201

Large scale synthesis of zinc oxide nanorods by homogeneous chemical vapour deposition and their characterisation  

Microsoft Academic Search

Zinc oxide nanorods in high yield have been prepared by the gas phase oxidation of zinc vapour followed by the collection of the oxide by aerosol condensation. Electron microscopy of the rods showed that these are single crystals with a diameter between 5–50 nm and with lengths over 1 ?m. Luminescence spectra showed a high intensity near band edge emission and a

Revathi Bacsa; Yolande Kihn; Marc Verelst; Jeannette Dexpert; Wolfgang Bacsa; Philippe Serp

2007-01-01

202

Low temperature synthesis of porous copper/zinc oxide  

SciTech Connect

A two-step urea aqueous solution process at a low temperature (90 deg. C) was employed for the preparation of a copper/zinc oxide material. Well defined porous spherical particles with average sizes of around 5 {mu}m in diameter were prepared first and then used as a support for further copper-zinc precipitation. It was found that the particle composition and shape were changed with applied stirring speed (100 rpm or 200 rpm) and that particle size is inversely proportional to the copper content in the particles. The particles preserved their size and shape after the heat treatment. Prepared Cu/ZnO samples showed catalytic activity for the reaction of steam reforming of methane. Samples were characterized by scanning field emission electron microscopy, energy dispersive X-ray analyses, X-ray powder diffraction, surface area analyses, and atomic absorption spectroscopy.

Podbrscek, Peter [National Institute of Chemistry, Hajdrihova 19, SI 1000 Ljubljana (Slovenia); Crnjak Orel, Zorica, E-mail: zorica.crnjak.orel@ki.si [National Institute of Chemistry, Hajdrihova 19, SI 1000 Ljubljana (Slovenia); Macek, Jadran [Faculty of Chemistry and Chemical Technology, Askerceva cesta 5, SI 1000 Ljubljana (Slovenia)

2009-08-05

203

Rare earth doped zinc oxide varistors  

DOEpatents

A varistor includes a Bi-free, essentially homogeneous sintered body of a ceramic composition including, expressed as nominal weight %, 0.2--4.0% oxide of at least one rare earth element, 0.5--4.0% Co{sub 3}O{sub 4}, 0.05--0.4% K{sub 2}O, 0.05--0.2% Cr{sub 2}O{sub 3}, 0--0.2% CaO, 0.00005--0.01% Al{sub 2}O{sub 3}, 0--2% MnO, 0--0.05% MgO, 0--0.5% TiO{sub 3}, 0--0.2% SnO{sub 2}, 0--0.02% B{sub 2}O{sub 3}, balance ZnO. 4 figs.

McMillan, A.D.; Modine, F.A.; Lauf, R.J.; Alim, M.A.; Mahan, G.D.; Bartkowiak, M.

1998-12-29

204

Rare earth doped zinc oxide varistors  

DOEpatents

A varistor includes a Bi-free, essentially homogeneous sintered body of a ceramic composition including, expressed as nominal weight %, 0.2-4.0% oxide of at least one rare earth element, 0.5-4.0% Co.sub.3 O.sub.4, 0.05-0.4% K.sub.2 O, 0.05-0.2% Cr.sub.2 O.sub.3, 0-0.2% CaO, 0.00005-0.01% Al.sub.2 O.sub.3, 0-2% MnO, 0-0.05% MgO, 0-0.5% TiO.sub.3, 0-0.2% SnO.sub.2, 0-0.02% B.sub.2 O.sub.3, balance ZnO.

McMillan, April D. (Knoxville, TN); Modine, Frank A. (Oak Ridge, TN); Lauf, Robert J. (Oak Ridge, TN); Alim, Mohammad A. (Medina, OH); Mahan, Gerald D. (Oak Ridge, TN); Bartkowiak, Miroslaw (Oak Ridge, TN)

1998-01-01

205

Experimental and Molecular Dynamics Simulations of Tribochemical Reactions with ZDDP: Zinc Phosphate–Iron Oxide Reaction  

Microsoft Academic Search

Zinc phosphate glass is considered to be the main constituent of tribofilms generated under boundary lubrication with zinc dialkyldithiophosphate (ZDDP), a well-known antiwear additive. The reaction occurring during friction between zinc phosphate glasses and steel native iron oxide layer is investigated by both an experimental approach and by Molecular Dynamics simulations (MD). The importance of this “tribochemical” reaction in the

Clotilde Minfray; Thierry Le Mogne; Jean-Michel Martin; Tasuku Onodera; Sayaka Nara; Shuko Takahashi; Hideyuki Tsuboi; Michihisa Koyama; Akira Endou; Hiromitsu Takaba; Momoji Kubo; Carlos A. Del Carpio; Akira Miyamoto

2008-01-01

206

A magnetic nanoparticles-zinc oxide/zinc hexacyanoferrate hybrid film for amperometric determination of tyrosine.  

PubMed

A method is described for the construction of a highly sensitive amperometric sensor for the detection of tyrosine, employing a magnetic nanoparticles-zinc oxide/zinc hexacyanoferrate (Fe3O4NP-ZnO/ZnHCF) hybrid film electrodeposited on the surface of a Pt electrode as working electrode. The sensor is based on electrocatalytic mechanism initiated by electrochemical oxidation of the reduced form of the hybrid film at +0.2 V vs. Ag/AgCl followed by completion of chemical oxidation of tyrosine. The sensor showed optimum response within 2 s at pH 2. The working/linear range of the sensor was 0.02-2.76 mM with a detection limit of 4 ?M. The sensor measured tyrosine level in serum, a potential biomarker of phenylketonuria. The working electrode lost only 5 % of its initial activity, when stored at 4 °C, after its regular use over a period of 100 days. PMID:23411873

Narang, Jagriti; Chauhan, Nidhi; Pundir, Shikha; Pundir, C S

2013-02-15

207

Exposure to zinc oxide nanoparticles affects reproductive development and biodistribution in offspring rats.  

PubMed

Understanding reproductive development effects and transferable properties to next generation of zinc oxide nanoparticles is necessary for prevention of its potential risks. To accomplish this, rats were exposed to zinc oxide nanomaterials (500 mg/kg bw) of less than 100 nm beginning 2 weeks before mating to postnatal day 4. In addition, body distribution of zinc concentration was evaluated in dams and offspring. Rat treated with nano-zinc oxide showed reduced number of born/live pups, decreased body weights of pups and increased fetal resorption. Zinc oxide nanomaterials were also distributed to organs such as mammary tissue of dams and liver and kidney of pups. These results indicate that zinc oxide nanoparticles-exposure before and during pregnancy and lactation could pose health risks to pregnant women and their fetus. PMID:23824008

Jo, Eunhye; Seo, Gyounbaek; Kwon, Jung-Taek; Lee, Mimi; Lee, Byoung cheun; Eom, Igchun; Kim, Philje; Choi, Kyunghee

2013-01-01

208

The zinc ferrite obtained by oxidative precipitation method as a catalyst in n-butanol conversion  

SciTech Connect

This paper presents the results of catalytic properties of n-butanol conversion of the zinc ferrite obtained by oxidative precipitation method. The zinc ferrite showed good dehydrogenating activity but also catalyzed consecutive bimolecular condensation of emerged aldehyde particles into symmetrical ketone. The zinc-iron oxide of spinel structure was prepared from ferrous sulfate, which forms as a waste during the titanium dioxide production. The X-ray diffraction methods (XRD, XRF) were used in determining the structure and composition of obtained zinc ferrite, while thermogravimetry (TG-DTG), and differential thermal analysis (DTA) were used in the study of thermal transformations of zinc spinel in air.

Klimkiewicz, Roman [W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, Wroclaw 2 50-950 (Poland)], E-mail: R.Klimkiewicz@int.pan.wroc.pl; Wolska, Jolanta; Przepiera, Aleksander; Przepiera, Krystyna; Jablonski, Maciej [Institute of Chemistry and Environmental Protection, Szczecin University of Technology, Al. Piastow 42, Szczecin 71-065 (Poland); Lenart, Stanislaw [Institute of Materials Engineering, Szczecin University of Technology, Al. Piastow 19, Szczecin 70-310 (Poland)

2009-01-08

209

Defect formation in chlorine-doped zinc oxide  

NASA Astrophysics Data System (ADS)

First-principles pseudopotential calculations have been performed to investigate the chorine-doped zinc oxide. From the calculated results, it is concluded that the ClO is energetically favorable and easy to form under the O-poor condition. Therefore, Cl-doping is an effective method to eliminate the oxygen vacancy in ZnO during the growth. However, the corresponding energy levels of ClO and Cli in band gap are rather deep so that they cannot play a role of donor or acceptor.

Liu, Bo; Gu, Mu; Liu, Xiaolin; Huang, Shiming; Ni, Chen

2013-10-01

210

Biofunctionalization of zinc oxide nanowires for DNA sensory applications  

PubMed Central

We report on the biofunctionalization of zinc oxide nanowires for the attachment of DNA target molecules on the nanowire surface. With the organosilane glycidyloxypropyltrimethoxysilane acting as a bifunctional linker, amino-modified capture molecule oligonucleotides have been immobilized on the nanowire surface. The dye-marked DNA molecules were detected via fluorescence microscopy, and our results reveal a successful attachment of DNA capture molecules onto the nanowire surface. The electrical field effect induced by the negatively charged attached DNA molecules should be able to control the electrical properties of the nanowires and gives way to a ZnO nanowire-based biosensing device.

2011-01-01

211

Thermally stimulated dielectric properties of polyvinylidenefluoride–zinc oxide nanocomposites  

Microsoft Academic Search

Thirty-micrometer thick polyvinylidenefluoride (PVDF)–zinc oxide (ZnO) nanocomposite samples in the mass ratio of ZnO (1–6%\\u000a (w\\/w)) have been prepared by solution mixing method. The nano- and microstructures of PVDF–ZnO nanocomposite of different\\u000a mass ratios were characterized by using high-resolution techniques such as atomic force microscopy (AFM) and scanning electron\\u000a microscopy (SEM). The SEM and AFM images show the presence of

Mulayam Singh Gaur; Ajay Pal Indolia

2011-01-01

212

Highly conducting zinc oxide thin films achieved without postgrowth annealing  

NASA Astrophysics Data System (ADS)

Heavily doped zinc oxide thin films were grown by radio frequency magnetron sputtering. High level of Al doping has been achieved at high growth temperatures (TG), thereby avoiding the need for postgrowth annealing. It is further shown that due to ionized impurity scattering, mobility decreases with increasing TG. Optical transmission spectra show that the bandgap varies from 3.22 to 3.68 eV with increasing Al content due to the combined effect of Burstien-Moss effect and bandgap renormalization.

Singh, Budhi; Khan, Zaheer Ahmed; Khan, Imran; Ghosh, Subhasis

2010-12-01

213

Growth and characterization of electrosynthesised zinc oxide thin films  

SciTech Connect

Zinc oxide (ZnO) films have been electrodeposited from an aqueous solution containing 0.1 M zinc nitrate as the electrolyte with pH around 5{+-}0.1. The deposition was carried out by galvanostatic reduction with an applied cathodic current density in the range between 5 and 20 mA cm{sup -2}. The influence of bath composition on the preparation of ZnO films is studied. The effects of zinc nitrate concentration and cathodic current density on the deposition rate of ZnO films were also studied. An optimum current density of 10 mA cm{sup -2} is identified for the growth of ZnO film with improved crystallinity and optical transmittance. The crystalline structure of the deposits studied by X-ray diffraction reveals the possibility of growing hexagonal ZnO films under suitable electrochemical conditions. The surface morphological studies by scanning electron micrographs revealed the presence of nodular appearance for films deposited at 800 deg. C bath temperatures.

Mahalingam, T.; John, V.S.; Sebastian, P.J

2003-01-25

214

Nanoscale Chemical Imaging of Zinc Oxide Nanowire Corrosion  

SciTech Connect

Nanoscale chemical images of individual bare and alumina-coated zinc oxide nanowires (NWs) were recorded using tip-enhanced second harmonic generation (SHG) spectroscopy before and after exposure to carbon dioxide and water vapor. The NWs were exposed for 0, 2, 4 and 6 days, and images were collected for the same bare nanowire after each two-day exposure period. Corrosion of the bare ZnO NW to zinc carbonate was evident from far-field and near-field SHG images and simultaneously recorded AFM data. The expected zinc carbonate corrosion product is SHG inactive. The AFM profile of the NW showed vertical and lateral expansion in different regions of the nanowire. The lower resolution far-field SHG signal decreased gradually and uniformly. The near-field SHG signal provided a profile of the evolving NW under investigation with a spatial resolution of ~100 nm which is in agreement with the AFM results. In contrast, alumina-coated ZnO NWs that were exposed in the same gas environment showed reduced, but still observable, degradation. The 3-nm thick alumina protective layer may have been insufficient to fully protect the NW, or the coating may have been incomplete. Thicker coatings preclude the tip-enhanced method. Nevertheless, the ability to monitor corrosion on a nanometer scale is a powerful tool for a fundamental understanding of surface chemical processes and should lead to the discovery of protective layers to prevent or delay degradation.

Cimatu, Katherine A [ORNL; Mahurin, Shannon Mark [ORNL; Meyer, Kent A [ORNL; Shaw, Robert W [ORNL

2012-01-01

215

ZINC  

EPA Science Inventory

This report summarizes the available information on zinc as it relates to its effects on man and his environment. Zinc is found in most soils, but some areas are deficient in it. Metallurgic operations contribute to zinc contamination in air, water and soil. Trace amounts of zinc...

216

A combined marginal deficiency of copper and zinc does not exacerbate oxidant stress asssociated with copper or zinc deficiency  

Technology Transfer Automated Retrieval System (TEKTRAN)

Both copper deficiency (Cu-def) and zinc deficiency (Zn-def) result in oxidative stress. Thus, an experiment was conducted to determine whether a marginal Zn-def amplified oxidative stress responses to a marginal Cu-def, or vice versa. Weanling male Sprague-Dawley rats were assigned to groups of 10 ...

217

Anodic oxidation of iron during the purification of sulfate zinc solutions  

Microsoft Academic Search

The anodic oxidation of iron in zinc solutions is carried out using a two-chamber electrolyzer separated by an anionite membrane.\\u000a The positive effect that copper ions in the solution have on the rate and completeness of the oxidation processes is shown.\\u000a This method is effective for cleaning the solutions of zinc production and processing the industrial zinc-containing wastes.

A. S. Kirpikov; S. V. Karelov; S. V. Mamyachenkov; V. A. Sergeev

2008-01-01

218

The oxidation resistance, hardness and constitution of some intermetallic compounds containing zinc  

Microsoft Academic Search

The majority of the binary compounds of zinc with the metals from titanium to copper inclusive has been prepared, hardness tested and oxidized in air at successively higher temperatures. A zinc-ruthenium and some zinc-gadolinium compounds have also been tested. From the oxidation results, the temperature corresponding to a weight change of 1 mg cm-2 over 4h was determined by interpolation.

H. E. N. Stone

1976-01-01

219

The oxidation resistance, hardness and constitution of some intermetallic compounds containing zinc  

Microsoft Academic Search

The majority of the binary compounds of zinc with the metals from titanium to copper inclusive has been prepared, hardness\\u000a tested and oxidized in air at successively higher temperatures. A zinc-ruthenium and some zinc-gadolinium compounds have also\\u000a been tested. From the oxidation results, the temperature corresponding to a weight change of 1 mg cm?2 over 4h was determined by interpolation.

H. E. N. Stone

1976-01-01

220

Investigation of Zinc Oxide nanorods growth on Indium Tin Oxide coated glass substrates  

Microsoft Academic Search

Zinc Oxide nanocrystals were fabricated in chemical bath deposition process by low temperature 95degC, on glass substrates covered with thin film of ITO. Experiments were repeated for different time of crystal growth. The results were investigated with scanning electron microscope and they show the way of nanostructures growth. Experiment exhibits the speed of nanoflowers growth and explains what cause the

Michal Byrczek; Paramaswar Hari; Jackob Donaldson; Helena Teterycz

2009-01-01

221

Preliminary Investigation into the Extraction of Zinc by Direct Oxidative Leaching of High-Manganese Sphalerite.  

National Technical Information Service (NTIS)

The direct oxidation of zinc sulphide ores in the spent electrolyte from zinc electrowinning cells has emerged as a viable alternative to the established practice in which ore is first roasted to form a readily soluble oxide. Laboratory-scale work on the ...

W. A. Nattrass

1983-01-01

222

Piezoelectric crystalline film of zinc oxide and method for making same  

Microsoft Academic Search

Piezoelectric crystalline film on a substrate, which is a crystalline zinc oxide film with a hexagonal crystal structure and a c-axis substantially perpendicular to the substrate surface, the crystalline zinc oxide film containing, as an additive element, uranium. The piezoelectric crystalline films have high resistivity and a smooth surface, and make it possible to produce piezoelectric transducers with good conversion

T. Mashio; H. Nishiyama; T. Ogawa

1980-01-01

223

Photocatalytic degradation of phenol under solar radiation using microwave irradiated zinc oxide  

Microsoft Academic Search

The effect of preparation method on the photocatalytic degradation of phenol using zinc oxides under solar radiation was studied in batch reactors. Zinc oxide was prepared by different methods by varying precipitating agents and the source of precursors and microwave irradiation time and characterized by XRD, surface area, acid sites and crystallite sizes. The photocatalytic reactions were carried out by

K. M. Parida; S. Parija

2006-01-01

224

Characteristics of anodic oxidation of zinc in alkaline solutions under intensified process conditions  

Microsoft Academic Search

A characteristic feature of anodic oxidation of powdered-zinc electrodes in alkaline solutions in storage batteries under heavy discharge conditions is that the process occurs at high polarization (up to 0.3 V) with a small volume of electrolyte per unit area of the reaction surface. A special electrode cell was designed for modeling the oxidation of porous zinc electrode under intensified

Y. L. Gunko; V. N. Flerov; M. G. Mikhalenko; V. I. Shishov

1986-01-01

225

Use of anodic oxide films to control the diffusion of zinc in GaAs  

Microsoft Academic Search

Experiments were performed to diffuse zinc into GaAs through anodic oxide layers of varying thickness and density. Using electrochemical profiling to determine both the electrically active zinc concentration and the diffusion depth with high resolution, the following results were found. The depth of the junction varies inversely with the thickness and the density of the oxide. However, the surface concentration

H. Cutlerywala; R. J. Roedel

1994-01-01

226

Preparation and properties of composite particles made by nano zinc oxide coated with titanium dioxide  

Microsoft Academic Search

In this paper, composite particles of nano zinc oxide coated with titanium dioxide were prepared and characterized by TEM, XRD, XPS and FT-IR, and the properties of the composite particles for photo catalysis and light absorption were studied. Tetrabutyl titanate (TBT) was hydrolyzed in an alcoholic suspension of nano zinc oxide with diethanolamine (DEA) as an additive, resulting in a

W. Wu; Y. W. Cai; J. F. Chen; S. L. Shen; A. Martin; L.-X. Wen

2006-01-01

227

Enhanced zinc oxide and graphene nanostructures for electronics and sensing applications  

Microsoft Academic Search

Zinc oxide and graphene nanostructures are important technological materials because of their unique properties and potential applications in future generation of electronic and sensing devices. This dissertation investigates a brief account of the strategies to grow zinc oxide nanostructures (thin film and nanowire) and graphene, and their applications as enhanced field effect transistors, chemical sensors and transparent flexible electrodes. Nanostructured

Ved Prakash Verma

2010-01-01

228

Divalent silver oxide-zinc cell having a unipotential discharge level  

Microsoft Academic Search

An alkaline silver oxide--zinc cell is described which has a negative electrode, an alkaline electrolyte, a positive electrode comprising divalent silver oxide housed in a positive terminal container, and a separator disposed between the negative electrode and the positive electrode. A discontinuous oxidizable metal, such as a zinc screen, is interposed between the positive electrode and the inner wall of

Kozawa

1975-01-01

229

Highly ordered zinc oxide nanotubules synthesized within the anodic aluminum oxide template  

Microsoft Academic Search

.   Zinc oxide (ZnO) nanotubules were prepared by sol-gel synthesis within the pores of an anodic aluminum oxide (AAO) template.\\u000a Scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED) and\\u000a X-ray Diffraction (XRD) were used to investigate the morphology and crystalloid structures of the ZnO nanotubules. The results\\u000a indicate that polycrystalline ZnO nanotubules are very uniformly assembled

Z. Wang; H. L. Li

2002-01-01

230

Oxidation of isopropylbenzene in presence of zinc and cadmium compounds  

SciTech Connect

This paper examines the electronic structure of zinc and cadmium to try to explain their superior tendency to complex formation to elements of the principal subgroup, alkaline-earth metals. The choice of Zn and Cd for the studies was also prompted by the small amount and contradictory nature of experimental facts relating to the use of their compounds as oxidation catalysts. Isopropylbenzene was used in the experiments and naphthenate salts were used as catalysts. The absence of variable-valence metals in the catalysts was confirmed by atomic emission. It is shown that the differences in catalytic acitvity of compounds of different metals inthe oxidation reaction are associated with difference in the complexing properties of the elements in the catalyst.

Kozlov, S.K.; Potekhin, V.M.; Tovstokhat 'ko, F.I.

1986-06-01

231

Fabrication of zinc oxide microstructures and their properties  

NASA Astrophysics Data System (ADS)

The bitter-melon-like and prism-like zinc oxide (ZnO) microstructures have been synthesized by hydrothermal route. Besides these microstructures, the ZnO material also consists of spherical nanoparticles with narrow size distribution. The as-synthesized ZnO material depicts hexagonal crystal structure. An optical band gap of 2.95 eV is determined from the UV-vis absorption band edge. The prism-like ZnO microstructure shows an ultraviolet near-band-edge emission at about 3.27 eV (380 nm) at room temperature which can be assigned to the radiative annihilation of excitons. The wide-band gap oxide materials like ZnO with short-wavelength PL emission can find application in light emitting devices.

Kumari, Latha; Li, Wenzhi; Vannoy, Charles H.; Leblanc, Roger M.; Wang, Dezhi

2009-03-01

232

Comparative study of aluminium-doped zinc oxide and ruthenium–aluminium co-doped zinc oxide by magnetron co-sputtering  

Microsoft Academic Search

Highly oriented polycrystalline aluminium-doped (Al-doped) and ruthenium–aluminium (Ru–Al) co-doped zinc oxide are prepared on borosilicate glass and polycarbonate (PC) substrates by co-sputtering at room temperature. To investigate the effect of Ru doping, co-sputtering is achieved by varying the sputtering power of Ru target while keeping the sputtering target power of Al-doped zinc oxide unchanged. Atomic force microscopy (AFM) data shows

L. M. Wong; S. J. Wang; W. K. Chim

2010-01-01

233

Properties of zinc oxide at low and moderate temperatures  

NASA Astrophysics Data System (ADS)

The properties of zinc oxide are examined as an analog of gallium nitride over a wide range of temperatures and possible applications. Its economic and environmental advantages are noted, as well as its radiation hardness, compared to group III nitrides. Methods for growing films and nanostructures with high crystal perfection are proposed. In particular, a magnetron technique for layer-by-layer growth of films is implemented which makes it possible to obtain high structural perfection and substantial thicknesses unattainable by several other methods. The feasibility of producing monochromatic UV radiation from films excited by short-wavelength radiation and electrons is demonstrated; this means that they may be useable as short-wavelength radiation sources. Efficient field emission by ZnO nanostructures and films is demonstrated and opens up the prospect of their use in vacuum microelectronics equipment. Nitrogen-doped ZnO films, in particular, have been used to fabricate a phototransistor with a sensitivity two orders of magnitude higher than conventional detectors. The physical basis for creating LEDs for different colors based on ZnO films and solid solutions with CdO is discussed. The importance of studying the physics and technology of zinc oxide-based devices is emphasized.

Lashkarev, G. V.; Karpyna, V. A.; Lazorenko, V. I.; Ievtushenko, A. I.; Shtepliuk, I. I.; Khranovskyy, V. D.

2011-03-01

234

Nanosized Zinc Oxide Induces Toxicity in Human Lung Cells  

PubMed Central

Zinc oxide nanoparticles (ZnO-NPs) are increasingly used in sunscreens, biosensors, food additives, pigments, rubber manufacture, and electronic materials. With the wide application of ZnO-NPs, concern has been raised about its unintentional health and environmental impacts. This study investigates the toxic effects of ZnO-NPs in human lung cells. In order to assess toxicity, human lung epithelial cells (L-132) were exposed to dispersion of 50?nm ZnO-NPs at concentrations of 5, 25, 50, and 100??g/mL for 24?h. The toxicity was evaluated by observing changes in cell morphology, cell viability, oxidative stress parameters, DNA damage analysis, and gene expression. Exposure to 50?nm ZnO-NPs at concentrations between 5 and 100??g/mL decreased cell viability in a concentration-dependent manner. Morphological examination revealed cell shrinkage, nuclear condensation, and formation of apoptotic bodies. The oxidative stress parameters revealed significant depletion of GSH level and increase in ROS levels suggesting generation of oxidative stress. ZnO-NPs exposure caused DNA fragmentation demonstrating apoptotic type of cell death. ZnO-NPs increased the expression of metallothionein gene, which is considered as a biomarker in metal-induced toxicity. To summarize, ZnO-NPs cause toxicity in human lung cells possibly through oxidative stress-induced apoptosis.

Sahu, Devashri; Kannan, G. M.; Vijayaraghavan, R.; Anand, T.; Khanum, Farhath

2013-01-01

235

An assessment of zinc oxide nanosheets as a selective adsorbent for cadmium  

NASA Astrophysics Data System (ADS)

Zinc oxide nanosheet is assessed as a selective adsorbent for the detection and adsorption of cadmium using simple eco-friendly extraction method. Pure zinc oxide nanosheet powders were characterized using field emission scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The zinc oxide nanosheets were applied to different metal ions, including Cd(II), Cu(II), Hg(II), La(III), Mn(II), Pb(II), Pd(II), and Y(III). Zinc oxide nanosheets were found to be selective for cadmium among these metal ions when determined by inductively coupled plasma-optical emission spectrometry. Moreover, adsorption isotherm data provided that the adsorption process was mainly monolayer on zinc oxide nanosheets.

Khan, Sher Bahadar; Rahman, Mohammed M.; Marwani, Hadi M.; Asiri, Abdullah M.; Alamry, Khalid A.

2013-09-01

236

Catalytic oxidation of cumene in presence of phenanthroline monoadducts of zinc(II)  

SciTech Connect

The authors studied catalytic oxidation of isopropylbenzene (IPB) in the presence of a number of previously synthesized phenanthroline monoadducts of zinc(II). The experimental results were compared with data on oxidation of IPB in presence with the corresponding (ZnL2 + phen) mixtures. It is shown that the components of mixed catalysts containing zinc compounds and o-phenanthroline enter into coordination interaction in the cumene undergoing oxidation, and form the corresponding phenanthroline monoadducts. The differences in the catalytic activities of the zinc complexes in cumene oxidation are probably associated with the characteristics of their interaction at the stage of degenerate chain branching.

Kozlov, S.K.; Potekhin, V.M.

1986-12-10

237

Zinc.  

National Technical Information Service (NTIS)

This report summarizes the available information on zinc as it relates to its effects on man and his environment. Zinc is found in most soils, but some areas are deficient in it. Metallurgic operations contribute to zinc contamination in air, water and so...

1978-01-01

238

Marginal zinc deficiency increases oxidative DNA damage in the prostate after chronic exercise.  

PubMed

Approximately 12% of Americans do not consume the recommended level of zinc and could be at risk for marginal zinc deficiency. Zinc functions in antioxidant defense and DNA repair and could be important for prostate health. We hypothesized that marginal zinc deficiency sensitizes the prostate to oxidative stress and DNA damage. Rats were fed a zinc-adequate (ZA; 30 mg Zn/kg) or marginally zinc-deficient (MZD; 5-6 mg Zn/kg) diet for 6 weeks. MZD increased p53 and PARP expression but no change in 8-hydroxy-2'-deoxyguanosine levels was detected. To examine the susceptibility to exogenous oxidative stress, rats fed a ZA or MZD diet were assigned to exercising (EXE) or sedentary (SED) groups for 9 weeks. MZD or EXE alone did not affect oxidative DNA damage in the prostate; however, combined MZD + EXE increased DNA damage in the dorsolateral lobe. PARP and p53 expression was not further induced with MZD + EXE, suggesting that MZD interferes with DNA repair responses to stress. Finally, the addition of phytase to the MZD diet successfully restored zinc levels in the prostate and decreased DNA damage back to ZA levels. Overall, this study suggests that marginal zinc deficiency sensitizes the prostate to oxidative stress and demonstrates the importance of maintaining optimal zinc nutrition in physically active populations. PMID:19836448

Song, Yang; Elias, Valerie; Loban, Andrei; Scrimgeour, Angus G; Ho, Emily

2009-10-28

239

Zinc oxide\\/redox mediator composite films-based sensor for electrochemical detection of important biomolecules  

Microsoft Academic Search

Electrochemical oxidation of serotonin (SN) onto zinc oxide (ZnO)-coated glassy carbon electrode (GCE) results in the generation of redox mediators (RMs) that are strongly adsorbed on electrode surface. The electrochemical properties of zinc oxide-electrogenerated redox mediator (ZnO\\/RM) (inorganic\\/organic) hybrid film-coated electrode has been studied using cyclic voltammetry (CV). The scanning electron microscope (SEM), atomic force microscope (AFM), and electrochemical techniques

Chun-Fang Tang; S. Ashok Kumar; Shen-Ming Chen

2008-01-01

240

Photophysical Behaviors of Single Fluorophores Localized on Zinc Oxide Nanostructures  

PubMed Central

Single-molecule fluorescence spectroscopy has now been widely used to investigate complex dynamic processes which would normally be obscured in an ensemble-averaged measurement. In this report we studied photophysical behaviors of single fluorophores in proximity to zinc oxide nanostructures by single-molecule fluorescence spectroscopy and time-correlated single-photon counting (TCSPC). Single fluorophores on ZnO surfaces showed enhanced fluorescence brightness to various extents compared with those on glass; the single-molecule time trajectories also illustrated pronounced fluctuations of emission intensities, with time periods distributed from milliseconds to seconds. We attribute fluorescence fluctuations to the interfacial electron transfer (ET) events. The fluorescence fluctuation dynamics were found to be inhomogeneous from molecule to molecule and from time to time, showing significant static and dynamic disorders in the interfacial electron transfer reaction processes.

Fu, Yi; Zhang, Jian; Lakowicz, Joseph R.

2012-01-01

241

Structure-dependent mechanical properties of ultrathin zinc oxide nanowires  

PubMed Central

Mechanical properties of ultrathin zinc oxide (ZnO) nanowires of about 0.7-1.1 nm width and in the unbuckled wurtzite (WZ) phase have been carried out by molecular dynamics simulation. As the width of the nanowire decreases, Young's modulus, stress-strain behavior, and yielding stress all increase. In addition, the yielding strength and Young's modulus of Type III are much lower than the other two types, because Type I and II have prominent edges on the cross-section of the nanowire. Due to the flexibility of the Zn-O bond, the phase transformation from an unbuckled WZ phase to a buckled WZ is observed under the tensile process, and this behavior is reversible. Moreover, one- and two-atom-wide chains can be observed before the ZnO nanowires rupture. These results indicate that the ultrathin nanowire possesses very high malleability.

2011-01-01

242

Doped zinc oxide window layers for dye sensitized solar cells  

NASA Astrophysics Data System (ADS)

The present paper reports the fabrication of dye sensitized solar cell (DSSC), where boron doped ZnO (BZO) and aluminum-boron co-doped ZnO (AZB) thin films were used as front window electrodes. The highly crystalline zinc oxide (ZnO) nanoparticles (NPs) synthesized by the sol-gel route were used as host material for the dye. The efficiencies of the DSSCs formed using the BZO and AZB as window layers were obtained to be 1.56 and 1.84%, respectively. The enhanced efficiency in the case of an AZB window layer based DSSC is attributed to the increase in conductivity induced by co-doping of Al and B and an increase in the number of conducting pathways between the window layer and NPs provided by the nanorods. This facilitates a new approach in the window layer (doped ZnO) for DSSC application.

Kumar, Vinod; Singh, Neetu; Kumar, Vijay; Purohit, L. P.; Kapoor, Avinashi; Ntwaeaborwa, Odireleng M.; Swart, Hendrik C.

2013-10-01

243

Aligned ZnO Nanorod Arrays Grown Directly on Zinc Foils and Zinc Spheres by a Low-Temperature Oxidation Method.  

SciTech Connect

Vertically aligned, dense ZnO nanorod arrays were grown directly on zinc foils by a catalyst-free, low-temperature (450-500 C) oxidization method. The zinc foils remain conductive even after the growth of ZnO nanorods on its surface. The success of this synthesis largely relies on the level of control over oxygen introduction. By replacing zinc foils with zinc microspheres, unique and sophisticated urchin-like ZnO nanorod assemblies can be readily obtained.

Gu, Dr Zhanjun [University of Georgia, Athens, GA; Paranthaman, Mariappan Parans [ORNL; Xu, Jun [ORNL; Pan, Zhengwei [University of Georgia, Athens, GA

2009-01-01

244

Band gap energies of solar micro/meso-porous composites of zinc (hydr)oxide with graphite oxides  

NASA Astrophysics Data System (ADS)

The band gap energies of micro/meso-porous zinc (hydr)oxide and its composites with 2 wt. % and 5 wt. % graphite oxides are reported using three optical characterization techniques. The obtained energy gaps (from 2.84 eV to 2.95 eV) of the composites are smaller than that for zinc oxide (~3.2 eV) and zinc (hydr)oxide (~3.06 eV). The band gap narrowing of the composite materials is due to the presence of defects, larger particle size, and weaker confinement. The bonds between zinc (hydr)oxide lattice and the carbon of graphene phase also contribute to this phenomenon. The structural properties of these materials are presented using Transmission Electron Microscopy, Scanning Tunneling Electron Microscopy, X-Ray analysis, and Two-Photon Fluorescence imaging Microscopy.

Islam, SM Z.; Gayen, Taposh; Seredych, Mykola; Mabayoje, Oluwaniyi; Shi, Lingyan; Bandosz, Teresa J.; Alfano, Robert R.

2013-07-01

245

Low temperature electrodeposition of zinc oxide layers as transparent conducting oxide window layers for CIGS solar cells  

Microsoft Academic Search

Electrodeposition of zinc oxide layers has been carried out in simple aqueous solutions at 80°C in presence of zinc ions and dissolved oxygen. Extrinsic n type doping has been proven to be effective by anionic substitution of oxygen by chlorine, using chloride containing electrolytes. Doping level upper values up to 9.1019 cm-3 have been obtained, associated with lateral resistivies in

Jean ROUSSET; Daniel LINCOT

2009-01-01

246

Zinc oxide waveguide produced by thermal oxidation of chemical bath deposited zinc sulphide thin films  

Microsoft Academic Search

ZnO waveguiding layers deposited onto soda lime glass were produced from the thermal oxidation of ZnS thin films elaborated by a carefully conducted chemical bath deposition (CBD) method. X-ray diffraction indicated that ZnO films possessing a polycrystalline hexagonal structure were obtained. M-line spectroscopy was used to determine the refractive index and the thickness of ZnO films which were 1.90 at

E. J Ibanga; C Le Luyer; J Mugnier

2003-01-01

247

Optical properties of zinc peroxide and zinc oxide multilayer nanohybrid films  

NASA Astrophysics Data System (ADS)

Zinc peroxide and zinc oxide nanoparticles were prepared and self-assembled hybrid nanolayers were built up using layer-by-layer (LbL) technique on the surface of glass substrate using the layer silicate hectorite and an anionic polyelectrolyte, sodium polystyrene sulfonate (PSS). Light absorption, interference and morphological properties of the hybrid films were studied to determine their thickness and refractive index. The influence of layer silicates and polymers on the self-organizing properties of ZnO 2 and ZnO nanoparticles was examined. X-ray diffraction revealed that ZnO 2 powders decomposed to ZnO (zincite phase) at relatively low temperatures (less than 200 °C). The optical thickness of the films ranged from 190 to 750 nm and increased linearly with the number of layers. Band gap energies of the ZnO 2/hectorite films were independent from the layer thickness and were larger than that of pure ZnO 2 nanodispersion. Decomposition of ZnO 2 to ZnO and O 2 at 400 °C resulted in the decrease of the band gap energy from 3.75 to 3.3 eV. Concomitantly, the refractive index increased in correlation with the formation of the zincite ZnO phase. In contrast, the band gap energies of the ZnO 2/PSS hybrid films decreased with the thickness of the nanohybrid layers. We ascribe this phenomenon to the steric stabilization of primary ZnO 2 particles present in the confined space between adjacent layers of hectorite sheets.

Seb?k, Dániel; Szabó, Tamás; Dékány, Imre

2009-05-01

248

Effect of food azo dyes tartrazine and carmoisine on biochemical parameters related to renal, hepatic function and oxidative stress biomarkers in young male rats.  

PubMed

Tartrazine and carmoisine are an organic azo dyes widely used in food products, drugs and cosmetics. The present study conducted to evaluate the toxic effect of these coloring food additives; on renal, hepatic function, lipid profile, blood glucose, body-weight gain and biomarkers of oxidative stress in tissue. Tartrazine and carmoisine were administered orally in two doses, one low and the other high dose for 30 days followed by serum and tissue sample collection for determination of ALT, AST, ALP, urea, creatinine, total protein, albumin, lipid profile, fasting blood glucose in serum and estimation of GSH, catalase, SOD and MDA in liver tissue in male albino rat. Our data showed a significant increase in ALT, AST, ALP, urea, creatinine total protein and albumin in serum of rats dosed with tartrazine and carmoisine compared to control rats and these significant change were more apparent in high doses than low, GSH, SOD and Catalase were decreased and MDA increased in tissue homogenate in rats consumed high tartrazine and both doses of carmoisine. We concluded that tartrazine and carmoisine affect adversely and alter biochemical markers in vital organs e.g. liver and kidney not only at higher doses but also at low doses. PMID:20678534

Amin, K A; Abdel Hameid, H; Abd Elsttar, A H

2010-08-03

249

High Rate Zinc Oxide Film Deposition by Atmospheric TPCVD Using Ar\\/Air Plasma Jets  

Microsoft Academic Search

In order to develop a functional film deposition process with a high deposition rate, as a basic study, deposition of zinc oxide film by atmospheric thermal plasma CVD (TPCVD) was carried out. As feedstock, working gas and substrate, ethanol diluted zinc acetate solution, Ar and 430 stainless steel were used. As for the deposition conditions, Ar gas flow rate was

ANDO Yasutaka; KOBAYASHI Akira; TOBE Shogo; TAHARA Hirokazu

250

EFFECT OF NANOSCALE ZINC OXIDE PARTICLES ON THE GERMINATION, GROWTH AND YIELD OF PEANUT  

Microsoft Academic Search

An investigation was initiated to examine the effects of nanoscale zinc oxide particles on plant growth and development. In view of the widespread cultivation of peanut in India and in other parts of the globe and in view of the potential influence of zinc on its growth, this plant was chosen as the model system. Peanut seeds were separately treated

T. N. V. K. V. Prasad; P. Sudhakar; Y. Sreenivasulu; P. Latha; V. Munaswamy; K. Raja Reddy; T. S. Sreeprasad; P. R. Sajanlal; T. Pradeep

2012-01-01

251

Influence Of pH On The Transport Of Nanoscale Zinc Oxide In Saturated Porous Media  

EPA Science Inventory

Widespread use of nanoscale zinc oxide (nZnO) in various fields causes subsurface environment contamination. Even though the transport of dissolved zinc ions in subsurface environments such as soils and sediments has been widely studied, the transport mechanism of nZnO in such e...

252

Controlled Co(II) Doping of Zinc Oxide Nanocrystals  

SciTech Connect

Dopants are non-native atoms commonly used to modify the properties of bulk semiconductors. In this paper we demonstrate that by controlling the addition of cobalt(II) to growing zinc oxide nanocrystals (ZnO NCs) it is possible to modulate the resulting properties. We show that the environment of cobalt may be controlled by varying the synthetic conditions, mainly through varying the time of dopant-precursor addition and concentration. These conditions prove critical to the resulting Co(II) configuration, which affects both the luminescent and photocatalytic properties of the ZnO NCs. Presynthetic doping with 2% Co(II) results in a 98% quenching of the visible emission of ZnO, whereas the same quantity doped post synthesis results in only a 60% quenching. The environment of cobalt in the ZnO wurtzite lattice is identified through UV-vis spectroscopy. The wurtzite structure of the ZnO lattice for all nanocrystalline species is confirmed through X-ray diffraction patterns obtained from a synchrotron radiation source. Postsynthetically doped Co(II) in ZnO NC is demonstrated to have potential applications as an 'on-off' sensor, as exemplified with nitric oxide.

S Bohle; C Spina

2011-12-31

253

Spatial atomic layer deposition of zinc oxide thin films.  

PubMed

Zinc oxide thin films have been deposited at high growth rates (up to ~1 nm/s) by spatial atomic layer deposition technique at atmospheric pressure. Water has been used as oxidant for diethylzinc (DEZ) at deposition temperatures between 75 and 250 °C. The electrical, structural (crystallinity and morphology), and optical properties of the films have been analyzed by using Hall, four-point probe, X-ray diffraction, scanning electron microscopy, spectrophotometry, and photoluminescence, respectively. All the films have c-axis (100) preferential orientation, good crystalline quality and high transparency (? 85%) in the visible range. By varying the DEZ partial pressure, the electrical properties of ZnO can be controlled, ranging from heavily n-type conductive (with 4 mOhm.cm resistivity for 250 nm thickness) to insulating. Combining the high deposition rates with a precise control of functional properties (i.e., conductivity and transparency) of the films, the industrially scalable spatial ALD technique can become a disruptive manufacturing method for the ZnO-based industry. PMID:22171693

Illiberi, A; Roozeboom, F; Poodt, P

2011-12-29

254

Dye-sensitized solid state photovoltaic cell based on composite zinc oxide/tin (IV) oxide films  

NASA Astrophysics Data System (ADS)

Dye-sensitized fully solid state cells having the structure of rough n-type semiconductor film comprising zinc and tin(IV) oxide/Ru-bipyridyl complex/p-CuI are found to generate high short-circuit photocurrents and open-circuit voltages in contrast to the cells of same type made with a single oxide (tin(IV) or zinc). The mechanism involved is explained as suppression recombinations of photogenerated carriers and dye ions resulting from interparticle charge transfer.

Tennakone, K.; Perera, V. P. S.; Kottegoda, I. R. M.; Kumara, G. R. R. A.

1999-02-01

255

Threshold voltage under white light illumination of zinc oxide based TFT in saturation regime  

NASA Astrophysics Data System (ADS)

The zinc oxide thin film transistor was fabricated on a SiO2/Si substrate by sol gel method. Electrical characteristics of the zinc oxide transistor under various illuminations were analyzed. The apparent shifting in threshold voltage of zinc oxide transistor under light illumination was explained as a result of the superposition of a photo-generated current on the dark current overall biases. Our model has been confirmed by demonstrating that the apparent threshold voltages calculated under different illumination intensities are perfectly matched with the experimental results. The model indicates that there is a photo-current associated with the photo-excitation process in zinc oxide thin-film transistor and the apparent threshold voltage under illumination is not the intrinsic threshold voltage of a device as measured in the dark; instead, it is monotonically shifted from the intrinsic value due to the increase in photo-current.

Mansouri, S.; Ben Mansour, N.; El Mir, L.; Al-Hartomy, Omar A.; Al Said, Said A. Farha; Al-Ghamdi, Ahmed A.; Yakuphanoglu, F.

2013-10-01

256

Biofunctionalized Zinc Oxide Field Effect Transistors for Selective Sensing of Riboflavin with Current Modulation.  

National Technical Information Service (NTIS)

Zinc oxide field effect transistors (ZnO-FET), covalently functionalized with single stranded DNA aptamers, provide a highly selective platform for label-free small molecule sensing. The nanostructured surface morphology of ZnO provides high sensitivity a...

B. Bayraktaroglu J. Hagen J. L. Chavez K. Leedy M. O. Stone N. Kelley-Loughnane R. R. Naik S. N. Kim

2011-01-01

257

Total zinc in zinc battery plates by EDTA titration  

Microsoft Academic Search

Zinc battery plate electrodes are analyzed for zinc oxide, zinc chloride, zinc fluoride, zinc carbonate, zinc oxychloride, total zinc, zinc as the metal, and trace metals. A variety of methods are used to determine each of these components. The amount of zinc in each of the zinc compounds is determined by multiplying the percent of the compound by the ratio

Vernon L. Hammersley; Naval Surface

1995-01-01

258

Characterization and optimization of zinc oxide films by r.f. magnetron sputtering  

Microsoft Academic Search

Zinc oxide films were deposited by a r.f. magnetron sputtering using a zinc oxide target. The deposited films were characterized as a function of deposition temperature, pressure, argon-oxygen gas flow ratio, target-substrate distance. The deposition conditions were optimized to give good quality films suitable for the fabrication of surface acoustic wave device. The films deposited at temperatures as low as

K. B. Sundaram; A. Khan

1997-01-01

259

Laser energy density, structure and properties of pulsed-laser deposited zinc oxide films  

Microsoft Academic Search

Zinc oxide thin films were deposited on soda lime glass substrates by pulsed laser deposition in an oxygen-reactive atmosphere at 20Pa and a constant substrate temperature at 300°C. A pulsed KrF excimer laser, operated at 248nm with pulse duration 10ns, was used to ablate the ceramic zinc oxide target. The structure, the optical and electrical properties of the as-deposited films

M. G. Tsoutsouva; C. N. Panagopoulos; M. Kompitsas

2011-01-01

260

Ultraviolet-illumination-enhanced photoluminescence effect in zinc oxide thin films  

Microsoft Academic Search

We report an enhancement effect of ultraviolet illumination on the photoluminescence intensities of zinc oxide thin films. Large-grain -textured zinc oxide thin films were deposited on amorphous-fused silica substrates using pulsed laser deposition. We found that the intensities of excitonic emission and green-band emission increased with ultraviolet light exposure time until a maximum value was achieved. We attribute this ultraviolet

Chunming Jin; Ashutosh Tiwari; Roger J. Narayan

2005-01-01

261

Epitaxial aluminum-doped zinc oxide thin films on sapphire. 1: Effect of substrate orientation  

Microsoft Academic Search

Epitaxial thin films of Al-doped zinc oxide have been grown on sapphire substrates by pulsed laser ablation. The effect of substrate temperature, background pressure of oxygen, and substrate orientation (A, M, R, C) on the orientation relationships between ZnO and sapphire have been evaluated using on- and off-axis X-ray diffractometry. Under all growth conditions zinc oxide, on A- and C-plane

V. Srikant; Valter Sergo; David R. Clarke

1995-01-01

262

Effect of zinc oxide nanoparticles on isothermal cure kinetics, morphology and mechanical properties of EPDM rubber  

Microsoft Academic Search

The morphology, cure behavior and mechanical properties of various ethylene-propylene-diene-monomer (EPDM) rubber containing zinc oxide nanoparticles (nZnO), were investigated comparing to those of EPDM with conventional zinc oxide (cZnO). The X-ray diffraction (XRD) analyses revealed that nZnO had lower grain sizes with respect to cZnO. The field-emission scanning electron microscopy (FESEM) studies showed that unlike the conventional system, the formation

Shahin Akhlaghi; Mohammadreza Kalaee; Saeedeh Mazinani; Effat Jowdar; Ali Nouri; Alireza Sharif; Navid Sedaghat

263

Kinetics of isopropylbenzene oxidation in presence of the catalytic system zinc naphthenate-1,10-phenanthroline  

SciTech Connect

The authors showed earlier that zinc and cadmium compounds activated by the heteroaromatic base 1,10-phenanthroline are effective catalysts of isopropylbenzene (IPB) and cumenyl hydroperoxide (CHP) oxidation. In this communication the authors present experimental data obtained in a study of the kinetics of accumulation of the products of IPB oxidation in presence of the catalytic system zinc naphthenate (ZnNf2)-1,10-phenanthroline (phen) at various temperatures.

Kozlov, S.K.; Tovstokhat'ko, F.I.; Potekhin, V.M.

1986-12-10

264

Surfactant-mediated growth of nanostructured zinc oxide thin films via electrodeposition and their photoelectrochemical performance  

Microsoft Academic Search

Zinc oxide (ZnO) thin films were electrodeposited from an aqueous zinc acetate solution onto fluorine-doped thin oxide (FTO) coated conducting glass substrates. The effect of organic surfactants like polyvinyl pyrrolidone (PVP), sodium dodecyl sulfate (SDS), polyethylene glycol (PEG), ethylene glycol (EG) and polyvinyl alcohol (PVA) on their structural, morphological, optical and photoelectrochemical properties was studied. The x-ray diffraction patterns revealed

A I Inamdar; S H Mujawar; V Ganesan; P S Patil

2008-01-01

265

Preparation of electrically conductive nano-powder of zinc oxide and application to transparent film coating  

Microsoft Academic Search

Preparation, characterization and application of electro-conductive nano-powders of zinc oxide (ZnO) are reported. The aim of the present study is to clarify whether reflection or absorption of near infrared ray (NIR) is effective in the transparent conductive films of zinc oxide. It is shown that, in the case of powder coating films, the NIR is absorbed, while, in the case

T. Izumi; K. Izumi; N. Kuroiwa; A. Senjuh; A. Fujimoto; M. Adachi; T. Yamamoto

2009-01-01

266

Heat-sterilized silver oxide--zinc cells cycle life studies. [4. 2 Ah  

Microsoft Academic Search

A JPL study was conducted to evaluate the cell design parameters that contribute to the cycle life of sealed, heat-sterilized silver oxide--zinc cells. Test cells having a rated capacity of 4.2 Ah were fabricated from zinc oxide electrodes prepared by the sintered Teflon process. Two separator variations were evaluated, one having acrylic acid and the other, methacrylic acid, grafted to

Arms

1973-01-01

267

Synthesis, Characterization and Dielectric Properties of Rodlike Zinc Oxide-Polyimide Nanocomposites  

Microsoft Academic Search

Novel polyimide-rodlike zinc oxide hybrid nanocomposite (PI-RL-ZnO) has been developed from the poly (amic acid) with different weight percentages (1, 3, 5 wt%) of using N-methyl-2-pyrrolidone (NMP) and N,N-dimethylacetamide (DMAc) as aprotic solvents. The prepared zinc oxide-polyimide nanocomposites were characterized for their structure, morphology, and thermal behavior employing Fourier transform infrared spectroscopy (FTIR), scanning electron micrograph (SEM), transmission electron micrograph (TEM),

Sema Vural; Süleyman Köytepe; Turgay Seçkin; ?brahim Ad?güzel

2012-01-01

268

Elaboration and adhesion of zinc oxide coatings on poly-ether-ether-ketone films  

Microsoft Academic Search

Zinc oxide coatings are deposited by r.f. magnetron sputtering from a ZnO target. A systematic study has been made on the influence of the sputtering parameters (oxygen partial pressure, total pressure, and r.f. power) both on the structure and on the chemical composition of the zinc oxide deposits. These thin films exhibit the zincite form with a preferred orientation along

S. Giancaterina; S. Ben Amor; E. M. Bachari; G. Baud; M. Jacquet; C. Perrin

2001-01-01

269

Zinc Dialkyldithiophosphate Oxidation by Cumene Hydroperoxide: Kinetic Studies by Raman and P NMR Spectroscopy  

Microsoft Academic Search

The oxidation of zinc dialkyldithiophosphates (ZDDPs) by cumene hydroperoxide in cyclohexane is studied by Raman and P NMR spectroscopy. The reaction proceeds in two main stages: oxidation of ZDDP to basic ZDDP, and oxidation of basic ZDDP to other products. Observation of phosphorus-containing reaction products by the two techniques yields approximate rate coefficients for the two stages. P NMR spectra

J. L. Paddy; N. C. J. Lee; D. N. Waters; W. Trott

1990-01-01

270

Ordered Nucleation Sites for the Growth of Zinc Oxide Nanofibers  

SciTech Connect

Organic photovoltaics (OPVs) offer a promising route to low cost photovoltaic (PV) technology that can be inexpensively manufactured on a large scale for use in power generation and commercial products. Solar power conversion efficiencies of laboratory scale OPV devices have recently reached ~5%; however, projected efficiencies of at least 10% will be required for commercialization. An analogous approach that has arisen recently that can potentially increase efficiencies employs metal oxide semiconductors as the electron acceptor, creating a hybrid organic-inorganic device. This approach offers the advantage that the conduction band of the oxide can be tuned in a systematic way through doping, thus potentially achieving higher photovoltages in the device. Additionally, nanostructures of these materials can be easily grown from precursor solutions, providing a technique to precisely control the nanoscale geometry. This work focuses on using ZnO, which is known to have high electron mobility (>100 cm2/Vs), as the electron acceptor. Nanofibers of ZnO can be grown from precursors such as zinc acetate or zinc nitrate to form arrays of nanofibers into which a conjugated polymer can be intercalated to form a composite PV device. The morphology of the nanofiber array is critical to the performance of the device, but current methods of nanofiber growth from a flat, polycrystalline nucleation layer allow for little morphological control. To overcome this limitation, we have created ordered arrays of ZnO nucleation sites with controllable size and spacing. Toluene solutions of diblock copolymer micelles with ZnCl2 incorporated into the micellar cores were spin-coated onto glass substrates and etched with an O2 plasma to yield hexagonally ordered arrays of ZnO nanoparticles that functioned as nucleation sites. Changing the concentration of ZnCl2 and the molecular weight and ratio of the diblock copolymer resulted in systematic variation in the size and spacing of the nucleation sites. Thermal anneal treatment provided further modification of the nucleation layer, from which ZnO nanofibers were successfully grown from solution, although at present it is not known if the geometry of the as-grown ZnO nanofibers precisely reflects that of the underlying nucleation layer. This work provides a simple and useful method for potentially controlling the nucleation of ZnO nanofibers to be used in hybrid ZnO/organic nanocomposite PV devices.

Wang, J.; Ginley, D.S.; Shaheen, S.

2006-01-01

271

Enzymatic reduction of azo and indigoid compounds.  

PubMed

A customer- and environment-friendly method for the decolorization azo dyes was developed. Azoreductases could be used both to bleach hair dyed with azo dyes and to reduce dyes in vat dyeing of textiles. A new reduced nicotinamide adenine dinucleotide-dependent azoreductase of Bacillus cereus, which showed high potential for reduction of these dyes, was purified using a combination of ammonium sulfate precipitation and chromatography and had a molecular mass of 21.5 kDa. The optimum pH of the azoreductase depended on the substrate and was within the range of pH 6 to 7, while the maximum temperature was reached at 40 degrees C. Oxygen was shown to be an alternative electron acceptor to azo compounds and must therefore be excluded during enzymatic dye reduction. Biotransformation of the azo dyes Flame Orange and Ruby Red was studied in more detail using UV-visible spectroscopy, high-performance liquid chromatography, and mass spectrometry (MS). Reduction of the azo bonds leads to cleavage of the dyes resulting in the cleavage product 2-amino-1,3 dimethylimidazolium and N approximately 1 approximately ,N approximately 1 approximately -dimethyl-1,4-benzenediamine for Ruby Red, while only the first was detected for Flame Orange because of MS instability of the expected 1,4-benzenediamine. The azoreductase was also found to reduce vat dyes like Indigo Carmine (C.I. Acid Blue 74). Hydrogen peroxide (H(2)O(2)) as an oxidizing agent was used to reoxidize the dye into the initial form. The reduction and oxidation mechanism of Indigo Carmine was studied using UV-visible spectroscopy. PMID:17891390

Pricelius, S; Held, C; Murkovic, M; Bozic, M; Kokol, V; Cavaco-Paulo, A; Guebitz, G M

2007-09-22

272

Zinc oxide nanoparticles show antidiabetic activity in streptozotocin-induced Types-1 and 2 diabetic rats.  

PubMed

Aim: The correlation of diabetes and an imbalance in zinc homeostasis makes zinc-based therapy an attractive proposition. In this study, zinc oxide nanoparticles were evaluated for antidiabetic effects and safety. Materials & methods: Zinc oxide nanoparticles (1, 3 and 10 mg/kg) were tested for antidiabetic activity in streptozotocin-induced Types-1 and 2 diabetic rats. Single-dose pharmacokinetic study, cytotoxicity, hemolysis, acute and subacute toxicity tests, and mechanism-of-action studies were performed. Results: Oral administration of zinc oxide nanoparticles resulted in significant antidiabetic effects - that is, improved glucose tolerance, higher serum insulin (70%), reduced blood glucose (29%), reduced nonesterified fatty acids (40%) and reduced triglycerides (48%). Nanoparticles were systemically absorbed resulting in elevated zinc levels in the liver, adipose tissue and pancreas. Increased insulin secretion and superoxide dismutase activity were also seen in rat insulinoma (RIN5f) cells. Nanoparticles were safe up to a 300 mg/kg dose in rats. Conclusion: Zinc oxide nanoparticles are a promising antidiabetic agent warranting further studies. Original submitted 9 July 2012; Revised submitted 27 November 2012. PMID:23427863

Umrani, Rinku D; Paknikar, Kishore M

2013-02-21

273

40 CFR 721.9538 - Lithium salt of sulfophenyl azo phenyl azo disulfostilbene (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Lithium salt of sulfophenyl azo phenyl azo disulfostilbene...Chemical Substances § 721.9538 Lithium salt of sulfophenyl azo phenyl azo disulfostilbene...substance identified generically as lithium salt of sulfophenyl azo phenyl azo...

2013-07-01

274

Research on Facilitation of Biodegradation of Azo Dye Wastewater by Bioelectrochemical Technology  

Microsoft Academic Search

Active brilliant red X-3B is a kind of azo dye which is difficult to biodegrade. The wastewater with azo dye is of chromaticity depth, high content of organic compounds, water quality changing great, and seriously impacts environment. Bioelectrochemical hydrolysis coupled with biological contact oxidation (BEH-BCO) was used to treat azo dye active brilliant red X-3B simulation wastewater. In this experiment,

Yuhua Zhao; Xiaoyi Cang; Decai Jin; Ruijiao Dong

2011-01-01

275

Zinc oxide nanoparticle removal from wounded human skin.  

PubMed

Aim: Nanoparticle removal from skin is relevant given the concern over topical nanoparticle toxicity. Zinc oxide nanoparticles (ZnO-NPs) are commonly used in sunscreens and their use is currently debated. This study explores the penetration and removal of ZnO-NPs from injured skin. Materials & methods:Ex vivo/in vivo human skin was tape-stripped and/or microneedled followed by ZnO-NP application. After 2 h, treated skin was washed three-times using soapy water. Multiphoton tomography assessed the ZnO-NP signal before and after washing. Results: Washing once removed over 85 and 83% of ZnO-NP signal from ex vivo intact and tape-stripped skin, respectively (p < 0.05) but only 28% (p = 0.5) was removed from puncture sites. A similar trend was found in vivo with removal of 85 and 93% of ZnO-NP signal from intact and tape-stripped skin, respectively (p < 0.05). Conclusion: Washing is effective for the removal of ZnO-NPs from superficial layers of intact and tape-stripped skin, but not from puncture wounds. Original submitted 5 July 2012; Revised submitted 3 October 2012; Published online 7 March 2013. PMID:23463920

Raphael, Anthony P; Sundh, Daniel; Grice, Jeffrey E; Roberts, Michael S; Soyer, H Peter; Prow, Tarl W

2013-03-07

276

Sonochemical approach for rapid growth of zinc oxide nanowalls  

NASA Astrophysics Data System (ADS)

The sonochemical process drives chemical reactions with sound fields by creating extraordinarily high density of energy, pressure and temperatures. The process resulted in a number of unexpected chemical species and thought-provoking results in the recent past. In this paper, we present a new sonochemical approach to synthesize ZnO (zinc oxide) nanowalls (NWalls) on aluminum and alumina coated substrates at room ambient conditions. We achieved highly dense and uniform ZnO NWalls in areas that are coated with Al or Al2O3 (alumina). The synthesis process was shown not to occur on Si, SiO2, Cr, or Ag surfaces. A series of experiments on understanding the growth kinetics offers detailed insight into the growth dynamics over time. Photoluminescence (PL) measurements, UV Vis spectroscopy, and SEM-EDS results confirm NWalls composed of crystalline ZnO that are formed via Al assisted growth induced by phase transformations under extraordinary pressure, temperature, and chemical growth kinetics. The chemical growth method as reported here, is applicable to arbitrary substrates coated with an Al thin film. We demonstrate the applications of the as-formed NWalls in UV photoconductors and gas sensors.

Nayak, Avinash P.; Katzenmeyer, Aaron M.; Gosho, Yasuhiro; Tekin, Bayram; Islam, M. Saif

2012-06-01

277

Characteristics of anodic oxidation of zinc in alkaline solutions under intensified process conditions  

SciTech Connect

A characteristic feature of anodic oxidation of powdered-zinc electrodes in alkaline solutions in storage batteries under heavy discharge conditions is that the process occurs at high polarization (up to 0.3 V) with a small volume of electrolyte per unit area of the reaction surface. A special electrode cell was designed for modeling the oxidation of porous zinc electrode under intensified discharge conditions, and also for selection and rapid verification of the influence of a number of additives on the anodic activity of the zinc electrode in a limited number of alkali. It was shown with the aid of chronoamperometric and potentiodynamic curves with compensation of the ohmic component that anodic oxidation of zinc under heavy discharge conditions proceeds with participation of a solid-phase mechanism.

Gun'ko, Y.L.; Flerov, V.N.; Mikhalenko, M.G.; Shishov, V.I.

1986-08-01

278

Understanding the defect structure of solution grown zinc oxide  

SciTech Connect

Zinc oxide (ZnO) is a wide bandgap semiconducting oxide with many potential applications in various optoelectronic devices such as light emitting diodes (LEDs) and field effect transistors (FETs). Much effort has been made to understand the ZnO structure and its defects. However, one major issue in determining whether it is Zn or O deficiency that provides ZnO its unique properties remains. X-ray absorption spectroscopy (XAS) is an ideal, atom specific characterization technique that is able to probe defect structure in many materials, including ZnO. In this paper, comparative studies of bulk and aqueous solution grown ({<=}90 Degree-Sign C) ZnO powders using XAS and x-ray pair distribution function (XPDF) techniques are described. The XAS Zn-Zn correlation and XPDF results undoubtedly point out that the solution grown ZnO contains Zn deficiency, rather than the O deficiency that were commonly reported. This understanding of ZnO short range order and structure will be invaluable for further development of solid state lighting and other optoelectronic device applications. - Graphical abstract: Highlights: Black-Right-Pointing-Pointer ZnO powders have been synthesized through an aqueous solution method. Black-Right-Pointing-Pointer Defect structure studied using XAS and XPDF. Black-Right-Pointing-Pointer Zn-Zn correlations are less in the ZnO powders synthesized in solution than bulk. Black-Right-Pointing-Pointer Zn vacancies are present in the powders synthesized. Black-Right-Pointing-Pointer EXAFS and XPDF, when used complementary, are useful characterization techniques.

Liew, Laura-Lynn [Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A-STAR), 3 Research Link, Singapore 117602 (Singapore); School of Materials Science and Engineering, Nanyang Technological University, Block N4.1 Nanyang Avenue, Singapore 639798 (Singapore); Sankar, Gopinathan, E-mail: g.sankar@ucl.ac.uk [Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Handoko, Albertus D. [Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A-STAR), 3 Research Link, Singapore 117602 (Singapore); Goh, Gregory K.L., E-mail: g-goh@imre.a-star.edu.sg [Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A-STAR), 3 Research Link, Singapore 117602 (Singapore); School of Materials Science and Engineering, Nanyang Technological University, Block N4.1 Nanyang Avenue, Singapore 639798 (Singapore); Kohara, Shinji [Japan Synchrotron Radiation Research Institute (JASRI), Mikazuki, Sayo, Hyogo 679-5198 (Japan)

2012-05-15

279

Zinc  

MedlinePLUS

... ulcers and promoting weight gain in people with eating disorders such as anorexia nervosa. Some people use zinc ... weight gain and improving depression in people with eating disorders such as anorexia nervosa. Treating hypogeusia, a rare ...

280

Recovery of zinc from leach residues with minimum iron dissolution using oxidative leaching.  

PubMed

Leaching was performed to recover zinc from a zinc leach residue which contained 9.87% Zn and 4.93% Fe. During sulfuric acid leaching, Fe was dissolved as well as Zn which can reduce the Zn extraction efficiency. Leaching the residue in the presence of an oxidizing reagent such as hydrogen peroxide or manganese dioxide significantly reduced the iron content of the leach liquor. Effect of pH, temperature, solid/liquid ratio, reaction time and hydrogen peroxide or manganese dioxide concentration on the recovery of zinc and iron in non-oxidative and oxidative leaching conditions were investigated. By using the optimum oxidative leaching conditions, iron recovery reduced from 70% in non-oxidative leaching to 0.4 and 5% in the presence of MnO(2) and H(2)O(2), respectively, with acceptable Zn recovery. This reduction in the iron content was due to the different iron compounds formed at different conditions. PMID:20516004

Alizadeh, Reza; Rashchi, Fereshteh; Vahidi, Ehsan

2010-06-01

281

Fabrication of lithium-doped zinc oxide film by anodic oxidation and its ferroelectric behavior  

SciTech Connect

A lithium-doped zinc oxide (ZnO) film was obtained by the anodic oxidation of a zinc sheet in a lithium hydroxide (LiOH) solution under an external DC voltage. The formation of the ZnO film on the surface of the Zn sheet is attributed to two simultaneous processes: the electrochemical oxidation of Zn to ZnO, and the chemical dissolution of ZnO. It was also confirmed that Li element was successfully introduced into the lattice of the ZnO film. The curves of the polarization versus applied field were measured to be hysteresis loops, suggesting ferroelectricity of the Li-doped ZnO film. The remanent polarization and the coercive field of the film were measured to be 4.7 x 10{sup -3} C m{sup -2} and 1.2 x 10{sup 7} V m{sup -1}, respectively. This ferroelectricity is believed to be the result of the occupation of off-centered positions in oxygen tetrahedra by the Li{sup +} ions.

Yu Ligang [Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, Beijing 100871 (China); Zhang Gengmin [Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, Beijing 100871 (China)], E-mail: zgmin@pku.edu.cn; Zhao Xingyu; Guo Dengzhu [Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, Beijing 100871 (China)

2009-03-05

282

Novel nanostructure zinc zirconate, zinc oxide or zirconium oxide pastes coated on fluorine doped tin oxide thin film as photoelectrochemical working electrodes for dye-sensitized solar cell.  

PubMed

Zinc zirconate (ZnZrO(3)) (ZZ), zinc oxide (ZnO) (ZO) and zirconium oxide (ZrO(2)) (ZRO) nano-particles were synthesized by simple sol-gel method. ZZ, ZO and ZRO nano-particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-Vis diffuse reflectance spectrum (DRS). Nanoporous ZZ, ZO and ZRO thin films were prepared doctor blade technique on the fluorine-doped tin oxide (FTO) and used as working electrodes in dye sensitized solar cells (DSSC). Their photovoltaic behavior were compared with standard using D35 dye and an electrolyte containing [Co(bpy)(3)](PF(6))(2), [Co(pby)(3)](PF(6))(3), LiClO(4), and 4-tert-butylpyridine (TBP). The properties of DSSC have been studied by measuring their short-circuit photocurrent density (Jsc), open-circuit voltage (VOC) and fill factor (ff). The application of ZnZrO(3) as working electrode produces a significant improvement in the fill factor (ff) of the dye-sensitized solar cells (ff=56%) compared to ZnO working electrode (ff=40%) under the same condition. PMID:23266694

Hossein Habibi, Mohammad; Askari, Elham; Habibi, Mehdi; Zendehdel, Mahmoud

2012-12-05

283

Novel nanostructure zinc zirconate, zinc oxide or zirconium oxide pastes coated on fluorine doped tin oxide thin film as photoelectrochemical working electrodes for dye-sensitized solar cell  

NASA Astrophysics Data System (ADS)

Zinc zirconate (ZnZrO3) (ZZ), zinc oxide (ZnO) (ZO) and zirconium oxide (ZrO2) (ZRO) nano-particles were synthesized by simple sol-gel method. ZZ, ZO and ZRO nano-particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-Vis diffuse reflectance spectrum (DRS). Nanoporous ZZ, ZO and ZRO thin films were prepared doctor blade technique on the fluorine-doped tin oxide (FTO) and used as working electrodes in dye sensitized solar cells (DSSC). Their photovoltaic behavior were compared with standard using D35 dye and an electrolyte containing [Co(bpy)3](PF6)2, [Co(pby)3](PF6)3, LiClO4, and 4-tert-butylpyridine (TBP). The properties of DSSC have been studied by measuring their short-circuit photocurrent density (Jsc), open-circuit voltage (VOC) and fill factor (ff). The application of ZnZrO3 as working electrode produces a significant improvement in the fill factor (ff) of the dye-sensitized solar cells (ff = 56%) compared to ZnO working electrode (ff = 40%) under the same condition.

Hossein Habibi, Mohammad; Askari, Elham; Habibi, Mehdi; Zendehdel, Mahmoud

2013-03-01

284

Copper\\/zinc ratio and systemic oxidant load: effect of aging and aging-related degenerative diseases  

Microsoft Academic Search

There is evidence that copper and zinc have pro-oxidant and antioxidant properties, respectively, so that their imbalance may be expected to condition oxidative stress status. Oxidative stress is relevant in aging and in age-related degenerative diseases. In this study, blood content of copper, zinc, and ceruloplasmin as well as of lipid peroxides were investigated in 81 healthy and 62 disabled

Andrea Mezzetti; Sante D Pierdomenico; Fabrizio Costantini; Ferdinando Romano; Domenico De Cesare; Franco Cuccurullo; Tiziana Imbastaro; Giuseppe Riario-Sforza; Franco Di Giacomo; Giovanni Zuliani; Renato Fellin

1998-01-01

285

Microcrystalline single and double junction silicon based solar cells entirely prepared by HWCVD on textured zinc oxide substrate  

Microsoft Academic Search

Microcrystalline silicon based single junction pin and amorphous-microcrystalline double junction pinpin solar cells were fabricated entirely by hot-wire chemical vapor deposition on textured zinc oxide substrates. The short circuit current density for microcrystalline pin cells shows an increase of 20–25% compared to unetched zinc oxide, indicating a better light trapping on textured zinc oxide substrate. The best initial conversion efficiency

P. Kumar; M. Kupich; W. Bock; R. O. Dusane; B. Schroeder

2006-01-01

286

Compatibility Studies of Some Azo Polymer Blends.  

National Technical Information Service (NTIS)

Azo polymers have many special properties. In the search for new materials for optical applications, such as reversible optical storage and nonlinear optical devices, azo polymers have attracted much attention. Polymers with low azo concentrations are par...

S. Xie A. Natansohn P. Rochon

1994-01-01

287

Desferrioxamine and zinc-desferrioxamine reduce lens oxidative damage.  

PubMed

Our purpose was to investigate the quality and morphology of cultured bovine lenses after exposure to hyperbaric oxygen (HBO) in the presence or absence of desferrioxamine (DFO) or zinc-desferrioxamine (Zn-DFO). Intact bovine lenses were cultured and exposed to HBO of 100% oxygen at 2.5 ATA for 120 min. One hundred and fifty lenses were included in the present study. Lenses were divided into study groups of 25 lenses each: (1a) HBO-exposed lenses; (1b) control lenses extracted from the contralateral eyes of group 1a and exposed to normal room air. (2a) HBO-exposed lenses treated with DFO; (2b) control lenses extracted from the contralateral eyes of group 2a exposed to normal room air in the presence of DFO (3a) HBO-exposed lenses treated with Zn-DFO; (3b) control lenses extracted from the contralateral eyes of group 3a, exposed to normal room air in the presence of Zn-DFO. Lens optical quality and structural changes were assessed. Oxygen toxicity to lenses was demonstrated by decreased light transmission, increase in focal length variability and a decrease in morphological integrity. Light intensity measurements showed a distinct pattern in control lenses. A different pattern was noticed for hyperbaric oxygen-exposed lenses. Focal length variability values were stable in control lenses and increased significantly in oxygen-exposed lenses. Structural damage to lenses was demonstrated by the appearance of bubbles between lens' fibers possibly demonstrating failure of lens tissue to cope with oxygen load. All measured parameters showed that both Zn-DFO and DFO attenuated the oxidative damage. The effect of DFO was small whereas Zn-DFO demonstrated a significantly stronger effect. Treatment of hyperbaric oxygen-exposed lenses with DFO only marginally reduced the oxidative damage. Treatment with Zn-DFO was superior in reducing the oxidative damage to lenses. These results indicate a possible role for Zn-DFO in the prevention of cataracts. PMID:17239855

Schaal, Shlomit; Beiran, Itzchak; Rozner, Hadas; Rubinstein, Irit; Chevion, Mordechai; Miller, Benjamin; Dovrat, Ahuva

2007-01-18

288

Comparison of several advanced oxidation processes for the decolorization of Reactive Red 120 azo dye in aqueous solution  

Microsoft Academic Search

In this study UV\\/TiO2, electro-Fenton (EF), wet-air oxidation (WAO), and UV\\/electro-Fenton (UV\\/EF) advanced oxidation processes (AOPs) have been applied to degrade Reactive Red 120 (RR120) dye in aqueous solution. The most efficient method on decolorization and mineralization of RR120 was observed to be WAO process. Photocatalytic degradation of RR120 by UV\\/TiO2 have been studied at different pH values. At pH

Erdal Kusvuran; Osman Gulnaz; Sibel Irmak; Osman M. Atanur; H. Ibrahim Yavuz; Oktay Erbatur

2004-01-01

289

Role of iron surface oxidation layers in decomposition of azo-dye water pollutants in weak acidic solutions  

Microsoft Academic Search

While decomposition of water pollutants in the presence of metallic iron can be strongly influenced by the nature and structure of the iron surface layer, the composition and structure of the layer produced and transformed in the decomposition process, have been meagerly investigated. The studies presented here establish strong relationships between the composition and structure of the iron oxidized surface

Jerzy A. Mielczarski; Gonzalo Montes Atenas; Ela Mielczarski

2005-01-01

290

A novel reflector of AZO thin films applicable for terahertz devices  

NASA Astrophysics Data System (ADS)

Despite the wide application of transparent conducting oxides in visible range, their properties and application in the terahertz range have not yet been extensively investigated. In this paper, we present a special AZO thin film - made reflector, which possesses both high reflectance in broad terahertz frequency band and high transmittance in visible range. The experimental data of the AZO films was in a good agreement to that of transfer matrix calculations. Meanwhile, the terahertz reflector of the AZO films used as reference was well verified in terahertz reflection measurement. The terahertz reflector of the AZO films is very suitable for the multispectral terahertz systems.

Lai, Wei-En; Zhu, Yao-Hua; Zhang, Huai-Wu; Wen, Qi-Ye

2013-04-01

291

Synthesis, characterization, and optical properties of zinc oxide nanostructures  

NASA Astrophysics Data System (ADS)

Chapter 1. A general introduction is presented that describes the new interdisciplinary field of nanoscience. The various unique properties of nanocrystals are highlighted, and different nanocrystal synthetic techniques are discussed. The importance of a technique that achieves control over nanocrystal size and morphology is stressed. Morphological control over zinc oxide nanocrystals using the "thermal decomposition of metal acetates" method is discussed. The numerous possible morphologies of nanocrystals of zinc oxide are described to illustrate the suitability of ZnO for a study of the relationship between nanocrystal morphology and properties. Chapter 2. A study of the growth, structure, self organization properties, and photoluminescence, of ZnO nanorods with 2 nm diameter is presented. The disparity in relative intensity of X-ray diffraction peaks between the ZnO nanorods and bulk ZnO is modeled using XRD refinement software, and shown to arise from preferred orientation, which occurs due to the nanorod shape. The effect of various synthesis parameters---reaction time, and capping agent to precursor molar ratio---on the nanorod growth and structure is probed using synchrotron X-ray diffraction by monitoring the width and position of the (002) diffraction peak. The stacking properties of the nanorods are studied using small angle X-ray diffraction, which can probe larger scale ordering due to the small angles used. The photoluminescence properties are studied using solution photoluminescence measurements, and strong quantum confinement effects are observed, due to the small diameter of the nanorods. Chapter 3. Morphological control of ZnO nanocrystals based on the coordinating power of the solvent used is presented. The various nano-shapes (nanotriangles, spherical nanoparticles, and nanorods) are studied by TEM and XRD. Using tilting TEM experiments and CrystalMaker models, the three dimensional nature of the nanotriangles is determined. Solution photoluminescence studies showed different PL properties for each nano-shape. The intensity of the green emission, attributed to defects, is found to correspond to the surface area to volume ratio of the nanocrystal, indicating that surface defects give rise to the emission. Control over nanocrystal shape is thus presented as a means to controlling green emission, which is usually unwanted in UV emitting applications. Chapter 4. Spherical ZnO dots of similar diameter with modified surfaces are prepared by introducing different ligands into the synthesis. The PL properties of the nanocrystals are studied, and it is found that dots prepared with solvents that can fill in oxygen vacancies exhibit weaker green emission. Zeta potential measurements confirm that the dots with weaker green emission are less positively charged (less oxygen vacancies). A novel method to calculate the dot diameter based on the energy of the green emission is presented, and the results are in good agreement with TEM measurements. The advantage to this method is the calculation is straightforward, and can be employed regardless of the degree of confinement. Chapter 5. The optical probing of single ZnO nanorods is presented. Near field scanning optical microscopy is employed to beat the diffraction limit of visible light (by placing the sample less than 10 nm from a pinpoint light source) and achieve optical images of individual nanorods. Synthesis of ZnO nanorods of the appropriate size scale for NSOM imaging is addressed. Although photoluminescence from single ZnO nanorods was not detected, in the resulting transmission mode optical images, in which light transmitted through the sample is collected, the nanorods appear brighter than the glass substrate. This anomalous contrast was found to vary with imaging wavelength and the presence of dopants in the nanorods. A model of NSOM transmission mode contrast based on refractive index is adopted to help explain the images, with materials of higher refractive index appearing brighter in transmitted NSOM images than those with a lower refractive i

Andelman, Tamar

292

Tunable infrared absorption and visible transparency of colloidal aluminum-doped zinc oxide nanocrystals.  

PubMed

Plasmonic nanocrystals have been attracting a lot of attention both for fundamental studies and different applications, from sensing to imaging and optoelectronic devices. Transparent conductive oxides represent an interesting class of plasmonic materials in addition to metals and vacancy-doped semiconductor quantum dots. Herein, we report a rational synthetic strategy of high-quality colloidal aluminum-doped zinc oxide nanocrystals. The presence of substitutional aluminum in the zinc oxide lattice accompanied by the generation of free electrons is proved for the first time by tunable surface plasmon absorption in the infrared region both in solution and in thin films. PMID:21970407

Buonsanti, Raffaella; Llordes, Anna; Aloni, Shaul; Helms, Brett A; Milliron, Delia J

2011-10-04

293

Optimization and modeling of zinc borate (2ZnO·3B 2O 3·3.5H 2O) production with the reaction of boric acid and zinc oxide  

Microsoft Academic Search

Production of zinc borate from boric acid was investigated in aqueous media. Zinc oxide and zinc borate are used as seed crystal to convert all the zinc oxide and to get a high reaction rate. The effect of some parameters such as temperature, stirring speed, H3BO3-to-ZnO ratio, % seed crystal\\/(H3BO3+ZnO) and time was studied on zinc borate production by using

Osman Nuri Ata; Enes ?ayan; Bengül Engin

2011-01-01

294

Antibacterial Activity of Dental Composites Containing Zinc Oxide Nanoparticles  

PubMed Central

The resin-based dental composites commonly used in restorations result in more plaque accumulation than other materials. Bacterial biofilm growth contributes to secondary caries and failure of resin-based dental composites. Methods to inhibit biofilm growth on dental composites have been sought for several decades. It is demonstrated here that zinc oxide nanoparticles (ZnO-NPs) blended at 10% (w/w) fraction into dental composites display antimicrobial activity and reduce growth of bacterial biofilms by roughly 80% for a single-species model dental biofilm. Antibacterial effectiveness of ZnO-NPs was assessed against Streptococcus sobrinus ATCC 27352 grown both planktonically and as biofilms on composites. Direct contact inhibition was observed by scanning electron microscopy and confocal laser scanning microscopy while biofilm formation was quantified by viable counts. An 80% reduction in bacterial counts was observed with 10% ZnO-NP-containing composites compared with their unmodified counterpart, indicating a statistically significant suppression of biofilm growth. Although, 20% of the bacterial population survived and could form a biofilm layer again, 10% ZnO-NP-containing composites maintained at least some inhibitory activity even after the third generation of biofilm growth. Microscopy demonstrated continuous biofilm formation for unmodified composites after one day growth, but only sparsely distributed biofilms formed on 10% ZnO-NP-containing composites. The minimum inhibitory concentration of ZnO-NPs suspended in S. sobrinus planktonic culture was 50 ?g/ml. 10% ZnO-NP-containing composites qualitatively showed less biofilm after one day anaerobic growth of a three-species initial colonizer biofilm after when compared to unmodified composites, but did not significantly reduce growth after three days.

Sevinc, Berdan Aydin; Hanley, Luke

2010-01-01

295

Alveolar Epithelial Cell Injury Due to Zinc Oxide Nanoparticle Exposure  

PubMed Central

Rationale: Although inhalation of zinc oxide (ZnO) nanoparticles (NPs) is known to cause systemic disease (i.e., metal fume fever), little is known about mechanisms underlying injury to alveolar epithelium. Objectives: Investigate ZnO NP–induced injury to alveolar epithelium by exposing primary cultured rat alveolar epithelial cell monolayers (RAECMs) to ZnO NPs. Methods: RAECMs were exposed apically to ZnO NPs or, in some experiments, to culture fluid containing ZnCl2 or free Zn released from ZnO NPs. Transepithelial electrical resistance (RT) and equivalent short-circuit current (IEQ) were assessed as functions of concentration and time. Morphologic changes, lactate dehydrogenase release, cell membrane integrity, intracellular reactive oxygen species (ROS), and mitochondrial activity were measured. Measurements and Main Results: Apical exposure to 176 ?g/ml ZnO NPs decreased RT and IEQ of RAECMs by 100% over 24 hours, whereas exposure to 11 ?g/ml ZnO NPs had little effect. Changes in RT and IEQ caused by 176 ?g/ml ZnO NPs were irreversible. ZnO NP effects on RT yielded half-maximal concentrations of approximately 20 ?g/ml. Apical exposure for 24 hours to 176 ?g/ml ZnO NPs induced decreases in mitochondrial activity and increases in lactate dehydrogenase release, permeability to fluorescein sulfonic acid, increased intracellular ROS, and translocation of ZnO NPs from apical to basolateral fluid (most likely across injured cells and/or damaged paracellular pathways). Conclusions: ZnO NPs cause severe injury to RAECMs in a dose- and time-dependent manner, mediated, at least in part, by free Zn released from ZnO NPs, mitochondrial dysfunction, and increased intracellular ROS.

Kim, Yong Ho; Fazlollahi, Farnoosh; Kennedy, Ian M.; Yacobi, Nazanin R.; Hamm-Alvarez, Sarah F.; Borok, Zea; Kim, Kwang-Jin; Crandall, Edward D.

2010-01-01

296

Thermal degradation behavior of selective zinc oxide coatings: An optical modeling approach  

Microsoft Academic Search

Anodically oxidized leaf zinc was exposed to several heat-treatment conditions, and the changes in the optical properties with such exposures were recorded in the form of spectral reflectance curves. The changes in these curves with exposure times were then modeled with several plausible coating structure changes. The approaches included an effective medium approximation and a nonstoichiometric semiconductor oxide model.

A. Scherer; O. T. Inal

1985-01-01

297

Effect of zinc oxide additives on the dielectric properties of steatite materials  

Microsoft Academic Search

The authors assess the effects of zinc oxides on the dielectric properties--specifically the permittivity, the tangent of the dielectric loss angle, and the bulk electrical resistivity--as well as on the sinterability and refractivity of a series of steatite ceramics composed of various ratios of the oxides of magnesium, silicon, aluminium, titanium, iron, barium, zirconium, potassium, and sodium.

A. V. Zonov; F. Ya. Kharitonov

1987-01-01

298

Nitric oxide inhibits the formation of zinc protoporphyrin IX and protoporphyrin IX  

Microsoft Academic Search

The aim of this study was to elucidate the mechanism by which curing agents, especially nitrite, inhibit the formation of zinc protoporphyrin IX (ZPP) in dry-cured hams such as Parma ham. The oxidation–reduction potential of model solutions was increased by the addition of nitrite, but it was not clear whether the formation of ZPP is inhibited by the oxidizing property

Jun-ichi Wakamatsu; Nobutaka Hayashi; Takanori Nishimura; Akihito Hattori

2010-01-01

299

Preparation and catalytic activity of Fe alginate gel beads for oxidative degradation of azo dyes under visible light irradiation  

Microsoft Academic Search

Fe alginate gel beads were prepared by adding sodium alginate aqueous solution drop-wise into the FeCl3 gelling solution using a syringe needle at room temperature, and measured in terms of size, mass and Fe content, then characterized using SEM, XRD, FT-IR, XPS and TGA, respectively. The gel beads were evaluated as the heterogeneous Fenton catalysts for oxidative degradation of two

Yongchun Dong; Wenjing Dong; Yanan Cao; Zhenbang Han; Zhizhong Ding

2011-01-01

300

41—THE EFFECTS OF A POLYETHYLENE OXIDE CONDENSATE AND SOME POLYETHYLENE GLYCOLS ON THE ABSORPTION SPECTRA OF CERTAIN AZO DYES  

Microsoft Academic Search

The presence of Dispersol A, a polyethylene oxide condensate, in an aqueous 1O mg.\\/l. Benzopurpurine 4B solution has a considerable effect upon the absorption spectrum of the dye. The spectral effect is similar to that of pyridine, and is independent of the Dispersol A concentration over the range 0·5 to 10 per cent. The absorption spectra of the dye (10

J. T. Martin; H. A. Standing

1949-01-01

301

Oxidation of 8-oxo-7,8-dihydro-2'-deoxyguanosine by oxyl radicals produced by photolysis of azo compounds.  

PubMed

Oxidative damage to 8-oxo-7,8-dihydroguanine (8-oxoG) bases initiated by photolysis of the water-soluble radical generator 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) has been investigated by laser kinetic spectroscopy. In neutral oxygenated aqueous solutions, 355 nm photolysis of AAPH initiates efficient one-electron oxidation of the 8-oxodG nucleosides directly monitored by the appearance of the 8-oxodG(*+)/8-oxodG(-H)* radicals at 325 nm. The reaction kinetics consist of a mechanism that includes the transformation of the 2-amidinoprop-2-peroxyl radicals (ROO*) derived from photolysis of AAPH to more reactive 2-amidinoprop-2-oxyl radicals (RO*), which directly react with the 8-oxoG bases. The major pathways for the formation of end products of 8-oxoG oxidation include the combination of the 8-oxodG(*+)/8-oxodG(-H)* radicals with superoxide (O(2)(*-)) and ROO* radicals in approximately 1:1 ratios, as demonstrated by experiments with Cu,Zn superoxide dismutase, to form dehydroguanidinohydantoin (Gh(ox)) derivatives. This mechanism was confirmed by analysis of the end products produced by the oxidation of two substrates: (1) the 8-oxoG derivative 2',3',5'-tri-O-acetyl-7,8-dihydroguanosine (tri-O-Ac-8-oxoG) and (2) the 5'-d(CCATC[8-oxoG]CTACC) sequence. The major products isolated by HPLC and identified by mass spectrometry methods were the tri-O-Ac-Gh(ox) and 5'-d(CCATC[Gh(ox)]CTACC products. PMID:20408566

Shao, Jie; Geacintov, Nicholas E; Shafirovich, Vladimir

2010-05-17

302

Highly efficient inverted polymer solar cells with reduced graphene-oxide-zinc-oxide nanocomposites buffer layer  

NASA Astrophysics Data System (ADS)

In this study, we reported a 36% improvement in the performance of inverted solar cells as a result of increased short-circuit current (JSC) obtained using a composition of zinc oxide (ZnO) and reduced graphene oxide (RGO) as an n-type buffer layer. RGO-ZnO nanocomposites show higher electron conductivity than intrinsic ZnO; moreover, they show reduced contact resistance at the interface between the active layer and n-type buffer layer. These factors prevent carrier loss resulting from defects and recombinations in the device, thereby significantly increasing the JSC value for the device. Thus, an efficiency of 4.15% was achieved for inverted solar cells with a controlled RGO-ZnO nanocomposites layer.

Woo Lee, Hyun; Young Oh, Jin; Il Lee, Tae; Soon Jang, Woo; Bum Yoo, Young; Sang Chae, Soo; Ho Park, Jee; Min Myoung, Jae; Moon Song, Kie; Koo Baik, Hong

2013-05-01

303

The interaction of zinc oxide-based dental cements with aqueous solutions of potassium fluoride.  

PubMed

The ability of zinc oxide-based dental cements (zinc phosphate and zinc polycarboxylate) to take up fluoride from aqueous solution has been studied. Only zinc phosphate cement was found to take up any measurable fluoride after 5 h exposure to the solutions. The zinc oxide filler of the zinc phosphate also failed to take up fluoride from solution. The key interaction for this uptake was thus shown to involve the phosphate groups of the set cement. However, whether this took the form of phosphate/fluoride exchange, or the formation of oxyfluoro-phosphate groups was not clear. Fluoride uptake followed radicaltime kinetics for about 2 h in some cases, but was generally better modelled by the Elovich equation, dq(t)/dt = alpha exp(-betaq(t)). Values for alpha varied from 3.80 to 2.48 x 10(4), and for beta from 7.19 x 10(-3) to 0.1946, though only beta showed any sort of trend, becoming smaller with increasing fluoride concentration. Fluoride was released from the zinc phosphate cements in processes that were diffusion based up to M(t)/M(infinity) of about 0.4. No further release occurred when specimens were placed in fresh volumes of deionised water. Only a fraction of the fluoride taken up was re-released, demonstrating that most of the fluoride taken up becomes irreversibly bound within the cement. PMID:18389342

Pawluk, K; Booth, S E; Coleman, N J; Nicholson, J W

2008-04-04

304

Zinc Oxide Nanostructures and High Electron Mobility Nanocomposite Thin Film Transistors  

Microsoft Academic Search

This paper reports on the synthesis of zinc oxide (ZnO) nanostructures and examines the performance of nanocomposite thin-film transistors (TFTs) fabricated using ZnO dispersed in both n- and p-type polymer host matrices. The ZnO nanostructures considered here comprise nanowires and tetrapods and were synthesized using vapor phase deposition techniques involving the carbothermal reduction of solid-phase zinc-containing compounds. Measurement results of

Flora M. Li; Gen-Wen Hsieh; Sharvari Dalal; Marcus C. Newton; James E. Stott; Pritesh Hiralal; Arokia Nathan; Paul A. Warburton; Husnu Emrah Unalan; Paul Beecher; Andrew J. Flewitt; Ian Robinson; Gehan Amaratunga; William I. Milne

2008-01-01

305

Transparent conductive indium-doped zinc oxide films prepared by atmospheric pressure plasma jet  

Microsoft Academic Search

Atmospheric-pressure plasma processing has attracted much interest for industrial applications due to its low cost, high processing speed and simple system. In this study, atmospheric-pressure plasma jet technique was developed to deposit indium-doped zinc oxide films. The inorganic metal salts of zinc nitrate and indium nitrate were used as precursors for Zn ions and In ions, respectively. The effect of

Kow-Ming Chang; Sung-Hung Huang; Chin-Jyi Wu; Wei-Li Lin; Wei-Chiang Chen; Chia-Wei Chi; Je-Wei Lin; Chia-Chiang Chang

2011-01-01

306

Evaluation of serum zinc level and plasma SOD activity in senile cataract patients under oxidative stress  

Microsoft Academic Search

An imbalance in the systemic redox status leading to oxidative stress has been an important factor in development of senile\\u000a cataracts, which is reflected by an increase in serum TBARS and a decrease in plasma SOD activity. Zinc has been an important\\u000a cofactor required for structural stability of SOD. In the present study the role of serum zinc level and

Indranil Chakraborty; Sanjoy Kunti; Mousumi Bandyopadhyay; Anindya Dasgupta; Gopal Deb Chattopadhyay; Sandip Chakraborty

2007-01-01

307

Early Signs of Oxidative Stress in Wheat Plants Subjected to Zinc Deficiency  

Microsoft Academic Search

Anti-oxidative defense systems in wheat plants were studied as a function of zinc deficiency in solution culture under glasshouse conditions. Zinc (Zn) deficiency enhanced cyanide-insensitive superoxide dismutase activity significantly, and decreased the activity of cyanide-sensitive superoxide dismutase before the appearance of visible effects of Zn deficiency. The plants with incipient deficiency of Zn also had significantly higher activities of nonspecific

Parma Nand Sharma; Praveen Kumar; Rajesh Kumar Tewari

2004-01-01

308

Epitaxial growth of zinc oxide thin films on silicon (100) substrates with zirconia buffer layer  

NASA Astrophysics Data System (ADS)

As an II-VI semiconductor, with wide bandgap and high exciton binding energy, zinc oxide has been favored for the new opto-electronic devices. One of the key issues for such applications is the integration of the zinc oxide onto silicon substrates. In this paper, we report a new integration methodology for depositing high quality zinc oxide thin films on silicon substrates. We have developed a novel epitaxial system for this purpose. An yttria stabilized zirconia (YSZ) buffer layer was used for depositing high quality, single crystalline zinc oxide films on Si (100) substrates. The heterostructure was developed with a pulsed laser deposition system. The results show that ZnO films grow epitaxially on YSZ buffered Si (100) substrates, with c-axis perpendicular to the substrate surface. High resolution image demonstrated that the interface between YSZ and ZnO is atomically smooth without any evidence of reaction. These zinc oxide films on Si (100), with YSZ buffer, showed excellent photoluminescence, evidenced with an extremely high exciton emission centered at 377 nm, at room temperature.

Aggarwal, Ravi; Jin, Chunming; Wei, Wei; Narayan, Jagdish; Narayan, Roger J.

2008-10-01

309

Comparing Inhaled Ultrafine versus Fine Zinc Oxide Particles in Healthy Adults  

PubMed Central

Rationale: Zinc oxide is a common, biologically active constituent of particulate air pollution as well as a workplace toxin. Ultrafine particles (< 0.1 ?m diameter) are believed to be more potent than an equal mass of inhaled accumulation mode particles (0.1–1.0 ?m diameter). Objectives: We compared exposure–response relationships for respiratory, hematologic, and cardiovascular endpoints between ultrafine and accumulation mode zinc oxide particles. Methods: In a human inhalation study, 12 healthy adults inhaled 500 ?g/m3 of ultrafine zinc oxide, the same mass of fine zinc oxide, and filtered air while at rest for 2 hours. Measurements and Main Results: Preexposure and follow-up studies of symptoms, leukocyte surface markers, hemostasis, and cardiac electrophysiology were conducted to 24 hours post-exposure. Induced sputum was sampled 24 hours after exposure. No differences were detected between any of the three exposure conditions at this level of exposure. Conclusions: Freshly generated zinc oxide in the fine or ultrafine fractions inhaled by healthy subjects at rest at a concentration of 500 ?g/m3 for 2 hours is below the threshold for acute systemic effects as detected by these endpoints.

Beckett, William S.; Chalupa, David F.; Pauly-Brown, Andrea; Speers, Donna M.; Stewart, Judith C.; Frampton, Mark W.; Utell, Mark J.; Huang, Li-Shan; Cox, Christopher; Zareba, Wojciech; Oberdorster, Gunter

2005-01-01

310

Hot gas desulfurization with oxides of zinc, iron, and vanadium  

SciTech Connect

The objective of this study is to develop an improved sorbent which can reduce H{sub 2}S levels up to 1 ppmv or less, which can stabilize zinc, and produce economically recoverable amounts of elemental sulfur during regeneration. For this purpose, the desulfurization performance of sorbents prepared by the addition of various amounts of V{sub 2}O{sub 5} to the zinc ferrite sorbent is investigated.

Akyurtlu, J.F.; Akyurtlu, A.

1992-01-01

311

Hot gas desulfurization with oxides of zinc, iron, and vanadium  

SciTech Connect

The objective of this study is to develop an improved sorbent which can reduce H{sub 2}S levels up to 1 ppmv or less, which can stabilize zinc, and produce economically recoverable amounts of elemental sulfur during regeneration. For this purpose, the desulfurization performance of sorbents prepared by the addition of various amounts of V{sub 2}O{sub 5} to the zinc ferrite sorbent is investigated.

Akyurtlu, J.F.; Akyurtlu, A.

1992-08-01

312

Palladium-Catalyzed Direct ortho Alkoxylation of Aromatic Azo Compounds with Alcohols.  

PubMed

An efficient and highly regioselective synthesis of 2-alkoxy aromatic azo compounds via palladium(II)-catalyzed alkoxylation of azobenzene derivatives directed by the azo group using alcohols as the alkoxylation reagents and PhI(OAc)2 as the oxidant has been developed. The method is applicable to both primary and secondary alcohols and affords moderate to good yields. PMID:24007335

Yin, Zhangwei; Jiang, Xiaoqing; Sun, Peipei

2013-09-16

313

ZINC  

Technology Transfer Automated Retrieval System (TEKTRAN)

Increasing interest by the public in components of the diet that promote health and well being prompt many questions about zinc. This mineral is a nutrient that plays key roles in regulating many biological functions ranging from cell development to brain function. Concern about the importance of zi...

314

Micro-structural investigations and paramagnetic susceptibilities of zinc oxide, europium oxide and their nanocomposite  

NASA Astrophysics Data System (ADS)

Nanoparticles of zinc oxide (ZnO), europium oxide (Eu2O3) and their nanocomposite system {(ZnO)0.55(Eu2O3)0.45} have been prepared by pyrophoric reaction and chemical co-precipitation methods. The precursor materials used for the synthesis were Zn(NO3)2·6H2O and bulk Eu2O3. For nanocrystallization, the as-prepared samples were annealed at 500 and 600 °C for 6 h. The X-ray diffractograms (XRD) confirmed the formation of desired phases of the nanoparticles of ZnO, Eu2O3 and nanocomposite of {(ZnO)0.55 (Eu2O3)0.45}. Particle sizes of all the samples have been estimated from the width of the XRD peaks using the Debye-Scherrer equation. Particle sizes, crystallographic phases, etc. extracted from the high resolution transmission electron microscopy of a few selected samples are in agreement with those obtained from the XRD. Field emission scanning electron microscopy showed that ZnO nanoparticles are more-or-less spherical in shape. Average magnetic susceptibilities of all the annealed samples measured in the temperature range of 300-14 K indicate that all the samples including the zinc oxide, which is normally diamagnetic in the bulk state, are paramagnetic and the data are tried to analyze by the Curie-Weiss law. Photo-luminescence data recorded at room temperature of all the samples indicate that the optical property of the ZnO nanoparticles are not affected by Eu2O3 nanoparticles in the nanocomposite system though its bulk magnetization is substantially enhanced by incorporating the Eu2O3 nanoparticles.

Modak, S.; Acharya, S.; Bandyopadhyay, A.; Karan, S.; Roy, S. K.; Chakrabarti, P. K.

2010-02-01

315

Epitaxial aluminum-doped zinc oxide thin films on sapphire. 1: Effect of substrate orientation  

SciTech Connect

Epitaxial thin films of Al-doped zinc oxide have been grown on sapphire substrates by pulsed laser ablation. The effect of substrate temperature, background pressure of oxygen, and substrate orientation (A, M, R, C) on the orientation relationships between ZnO and sapphire have been evaluated using on- and off-axis X-ray diffractometry. Under all growth conditions zinc oxide, on A- and C-plane sapphire, grew with the c-axis perpendicular to the substrate. In contrast, on M and R orientations of sapphire, ZnO grew with its c-axis parallel or perpendicular to the substrate depending on the substrate temperature and background pressure employed during growth. In all cases only one unique in-plane relationship between the sapphire substrate and the zinc oxide film was found with the exception of the M-plane at high substrate temperatures.

Srikant, V.; Sergo, V.; Clarke, D.R. [Univ. of California, Santa Barbara, CA (United States). Materials Dept.

1995-07-01

316

BIOCHEMISTRY OF MOBILE ZINC AND NITRIC OXIDE REVEALED BY FLUORESCENT SENSORS  

PubMed Central

Biologically mobile zinc and nitric oxide (NO) are two prominent examples of inorganic compounds involved in numerous signaling pathways in living systems. In the past decade, a synergy of regulation, signaling, and translocation of these two species has emerged in several areas of human physiology, providing additional incentive for developing adequate detection systems for Zn(II) ions and NO in biological specimens. Fluorescent probes for both of these bioinorganic analytes provide excellent tools for their detection, with high spatial and temporal resolution. We review the most widely used fluorescent sensors for biological zinc and nitric oxide, together with promising new developments and unmet needs of contemporary Zn(II) and NO biological imaging. The interplay between zinc and nitric oxide in the nervous, cardiovascular, and immune systems is highlighted to illustrate the contributions of selective fluorescent probes to the study of these two important bioinorganic analytes.

Pluth, Michael D.; Tomat, Elisa; Lippard, Stephen J.

2010-01-01

317

Synthesis and characterization of zinc\\/iron oxide composite nanoparticles and their antibacterial properties  

Microsoft Academic Search

Inorganic metal oxides may serve as effective disinfectants, due to their relatively non-toxic profile, chemical stability and efficient antibacterial activity. Among metal oxide nanoparticles, zinc oxide demonstrates significant bacterial growth inhibition on a broad spectrum of bacteria, mainly by catalysis of reactive oxygen species (ROS) formation from water and oxygen. Aqueous suspensions of ZnO nanoparticles (ZnO nanofluids) are the preferred

Tamar Gordon; Benny Perlstein; Ofir Houbara; Israel Felner; Ehud Banin; Shlomo Margel

2011-01-01

318

EXAMINATION OF THE OXIDATION PROTECTION OF ZINC COATINGS FORMED ON COPPER ALLOYS AND STEEL SUBSTRATES  

SciTech Connect

The exposure of metallic components at aggressive high temperature environments, usually limit their usage at similar application because they suffer from severe oxidation attack. Copper alloys are used in a wide range of high-quality indoor and outdoor applications, statue parts, art hardware, high strength and high thermal conductivity applications. On the other hand, steel is commonly used as mechanical part of industrial set outs or in the construction sector due to its high mechanical properties. The aim of the present work is the examination of the oxidation resistance of pack cementation zinc coatings deposited on copper, leaded brass and steel substrates at elevated temperature conditions. Furthermore, an effort made to make a long-term evaluation of the coated samples durability. The oxidation results showed that bare substrates appear to have undergone severe damage comparing with the coated ones. Furthermore, the mass gain of the uncoated samples was higher than this of the zinc covered ones. Particularly zinc coated brass was found to be more resistant to oxidation conditions in which it was exposed as it has the lower mass gain as compared to the bare substrates and zinc coated copper. Zinc coated steel was also proved to be more resistive than the uncoated steel.

Papazoglou, M.; Chaliampalias, D.; Vourlias, G.; Pavlidou, E.; Stergioudis, G. [Department of Physics, Aristotle University of Thessaloniki, 541 24 Thessaloniki (Greece); Skolianos, S. [Physical Metallurgy Laboratory, Department of Mechanical Engineering, Aristotle University of Thessaloniki, 541 24, Thessaloniki (Greece)

2010-01-21

319

Spectroscopic characterization of zinc oxide nanorods synthesized by solid-state reaction  

NASA Astrophysics Data System (ADS)

Well-crystallized zinc oxide nanorods have been fabricated by single step solid-state reaction using zinc acetate and sodium hydroxide, at room temperature. The sodium lauryl sulfate (SLS) stabilized zinc oxide nanorods were characterized by using X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and photoluminescence spectroscopy. The X-ray diffraction revealed the wurtzite structure of zinc oxide. The size estimation by XRD and TEM confirmed that the ZnO nanorods are made of single crystals. The growth of zinc oxide crystals into rod shape was found to be closely related to its hexagonal nature. The mass ratio of SLS:ZnO in the nanorods was found to be 1:10 based on the thermogravimetric analysis. Blue shift of photoluminescence emission was noticed in the ZnO nanorods when compared to that of ZnO bulk. FT-IR analysis confirmed the binding of SLS with ZnO nanorods. Apart from ease of preparation, this method has the advantage of eco-friendliness since the solvent and other harmful chemicals were eliminated in the synthesis protocol.

Prasad, Virendra; D'Souza, Charlene; Yadav, Deepti; Shaikh, A. J.; Vigneshwaran, Nadanathangam

2006-09-01

320

Defect Mediated Ferromagnetism in Zinc Oxide Thin Film Heterostructures  

NASA Astrophysics Data System (ADS)

Recent developments in the field of spintronics (spin based electronics) have led to an extensive search for materials in which semiconducting properties can be integrated with magnetic properties to realize the objective of successful fabrication of spin-based devices. Since zinc oxide (ZnO) posits a promising player, it is important to elucidate the critical issues regarding the origin and nature of magnetism in ZnO thin film heterostructures. Another critical issue in the development of practical devices based on metal oxides is the integration of high quality epitaxial thin films on the existing technology based on Si (100) substrates, which requires appropriate substrate templates. The present research work is focused on the study of room temperature ferromagnetism (RTFM) caused by intrinsic defects and precise control of RTFM using thermal treatments and laser and ion irradiation. We performed a systematic study of the structural, chemical, electrical, optical and magnetic properties of undoped ZnO films grown under different conditions as well as the films that were annealed in various environments. Oxygen annealed films displayed a sequential transition from ferromagnetism to diamagnetism as a function of the annealing temperature. An increase in the green band intensity has been observed in oxygen annealed ZnO films. Reversible switching of room-temperature ferromagnetism and n-type conductivity have been demonstrated by oxygen and vacuum annealing. Detailed electron energy loss spectroscopy and secondary ion mass spectroscopy studies have been presented to rule out the possibility of external source of magnetism. Electron-Paramagnetic Resonance (EPR) measurements indicate the presence of a broad peak at g=2.01. This would be most consistent with the magnetic moment arising from the oxygen vacancies (g=1.996), although the possible contribution from Zn vacancies (g=2.013) cannot be entirely ruled out. The magnetic moment in these films may arise from the unpaired 2p electrons at the O sites surrounding the zinc vacancy with each nearest-neighbor O atom carrying a magnetic moment ranging from 0.49 to 0.74 muB and the oxygen vacancies may provide the coupling mechanism. Results of EPR study are found to be in agreement with the results of magnetization and conductivity measurements. The effect of UV Excimer laser irradiation on electrical, magnetic and optical properties of ZnO thin films has been studied. Increases in the electrical conductivity and magnetic moment have been controlled precisely with the number of laser pulses, without altering the Wurtzite crystal structure and n-type semiconducting characteristics of the films. The laser-induced ferromagnetism and concomitant conductivity enhancement can be reversed through subsequent thermal annealing. It has also been shown that heavy swift ion irradiation can also create room temperature ferromagnetism in oxygen annealed insulating ZnO films. Saturation magnetic moments increase with increasing ion dose. A systematic study of the thickness dependency of the structural, electrical and magnetic properties of undoped ZnO thin films has been presented. The role of film/substrate interface in magnetism has been discussed. It has been shown by EPR study and oxidative quenching of ferromagnetism that oxygen vacancies are the key mediating defect in ferromagnetic ZnO thin films. Finally growth of epitaxial ZnO on Si (100) substrates has been achieved using a titanium nitride (TiN)/strontium titanate (STO) template layer. It has been shown that TiN can be grown epitaxially on silicon substrates. It was observed that, crystallographic orientations of ZnO on STO can be controlled by the oxygen pressure and substrate temperature during the deposition. The detailed x-ray diffraction, transmission electron microscopy (TEM), electrical and magnetic characterization results for the deposited films have been carried out. The above mentioned methods provide a controlled way to study changes in magnetic, electrical and optical properties of ZnO films and determine the mechanis

Mal, Siddhartha

321

Electrophoretic deposition of aqueous nano-sized zinc oxide suspensions on a zinc electrode  

Microsoft Academic Search

Electrophoretic deposition (EPD) was used to form ZnO deposits. ZnO with an average particle size of 40nm was dispersed in water with the addition of an appropriate amount of anionic polyelectrolyte. Uniform and bubble-free ZnO deposits have been obtained via EPD on a zinc anode in an aqueous suspension. The obtained deposits showed good sinterability.

Fengqiu Tang; Yoshio Sakka; Tetsuo Uchikoshi

2003-01-01

322

Growth of biepitaxial zinc oxide thin films on silicon (100) using yttria-stabilized zirconia buffer layer  

NASA Astrophysics Data System (ADS)

In this work, an approach for integrating zinc oxide thin films with Si(100) substrates using an epitaxial tetragonal yttria-stabilized zirconia buffer layer is reported. Selected area electron diffraction measurements revealed the following epitaxial relationship: [110]YSZ?[100]Si and (001)YSZ?(001)Si. X-ray diffraction studies demonstrated that subsequent growth of the zinc oxide thin film on the yttria-stabilized zirconia buffer layer occurred with the following epitaxial relationship: (0002)ZnO?(001)YSZ. The full width at half maximum value for the (0002) peak of zinc oxide was small (~0.16°), which indicated good crystalline quality. Transmission electron microscopy revealed that the zinc oxide thin film grew epitaxially on an yttria-stabilized zirconia buffer layer in two different orientations, where one orientation was rotated by 30° from the other. The orientation relationship in this case was [1010]ZnO?[100]YSZ or [2110]ZnO?[100]YSZ and (0002)ZnO?(001)YSZ. The biepitaxial growth of the zinc oxide thin film has been explained in the framework of domain matching epitaxy. Optical emission measurements showed a strong excitonic emission peak from the zinc oxide thin film at ~377 nm. Minimal green band emission in the photoluminescence spectrum indicated that the concentration of point defects was low. Integration of epitaxial zinc oxide thin films with Si(100) substrates is an important step toward developing practical applications of zinc oxide in a variety of optoelectronic devices.

Aggarwal, Ravi; Jin, Chunming; Pant, Punam; Narayan, J.; Narayan, Roger J.

2008-12-01

323

The decolorization and mineralization of acid orange 6 azo dye in aqueous solution by advanced oxidation processes: a comparative study.  

PubMed

The comparison of different advanced oxidation processes (AOPs), i.e. ultraviolet (UV)/TiO(2), O(3), O(3)/UV, O(3)/UV/TiO(2), Fenton and electrocoagulation (EC), is of interest to determine the best removal performance for the destruction of the target compound in an Acid Orange 6 (AO6) solution, exploring the most efficient experimental conditions as well; on the other hand, the results may provide baseline information of the combination of different AOPs in treating industrial wastewater. The following conclusions can be drawn: (1) in the effects of individual and combined ozonation and photocatalytic UV irradiation, both O(3)/UV and O(3)/UV/TiO(2) processes exhibit remarkable TOC removal capability that can achieve a 65% removal efficiency at pH 7 and O(3) dose=45mg/L; (2) the optimum pH and ratio of [H(2)O(2)]/[Fe(2+)] found for the Fenton process, are pH 4 and [H(2)O(2)]/[Fe(2+)]=6.58. The optimum [H(2)O(2)] and [Fe(2+)] under the same HF value are 58.82 and 8.93mM, respectively; (3) the optimum applied voltage found in the EC experiment is 80V, and the initial pH will affect the AO6 and TOC removal rates in that acidic conditions may be favorable for a higher removal rate; (4) the AO6 decolorization rate ranking was obtained in the order of O(3)

Hsing, Hao-Jan; Chiang, Pen-Chi; Chang, E-E; Chen, Mei-Yin

2006-11-07

324

Controlled Growth of one-dimensional zinc oxide nanostructures in the pulsed electrodeposition mode  

SciTech Connect

Zinc oxide nanostructures are objects of study in the field of optoelectronics, solar power engineering, nanosensorics, and catalysis. For the purpose of the controlled growth of one-dimensional submicrometer zinc oxide structures in the pulsed electrodeposition mode, the effect of the pulse electrolysis parameters on the morphology of ZnO layers, their optical properties, and structural and substructural characteristics is determined using X-ray diffraction, optical spectrophotometry, and atomic-force microscopy. The possibility of fabricating arrays of ZnO nanowires with different geometrical shapes, perpendicular to the substrate surface, by varying the frequency of cathode-substrate potential pulses is shown.

Klochko, N. P., E-mail: klochko_np@mail.ru; Khrypunov, G. S. [National Technical University 'Kharkiv Polytechnical Institute' (Ukraine); Myagchenko, Yu. O.; Melnychuk, E. E. [Taras Shevchenko National University of Kyiv (Ukraine); Kopach, V. R.; Klepikova, E. S.; Lyubov, V. M. [National Technical University 'Kharkiv Polytechnical Institute' (Ukraine); Kopach, A. V.

2012-06-15

325

Using C??? Sputtering to Improve Detection Limit of Nitrogen in Zinc Oxide  

SciTech Connect

C??? sputtering was firstly used to determine depth profile of nitrogen in zinc oxide materials by time-of-flight secondary ion mass spectrometry (ToF-SIMS). Compared to traditional Cs+ sputtering depth profiling, the C??? sputtering provides over 200 times of effective signal intensity and the detection limit is about 10 times better. In addition, our X-ray photoelectron spectroscopy (XPS) results show that sputtering zinc oxide materials by 10 keV C??? leads to very weak carbon deposition at bottom of the sputter crater.

Zhu, Zihua; Shutthanandan, V.; Nachimuthu, Ponnusamy

2010-05-11

326

Synthesis of Silicon and Zinc Oxide Nanowhiskers and Studies of Their Properties  

NASA Astrophysics Data System (ADS)

The conditions and mechanisms for purposeful pattern formation on the surface of single-crystal silicon wafers by building up silicon or zinc oxide by the vapor-liquid-crystal (VLC) mechanism were studied. For the polished silicon surface we developed a procedure for preparation of areas with randomly distributed nanosized gold metal particles - whisker growth initiators. The arrays of randomly distributed silicon and zinc oxide whiskers were grown. The emission cells with a pointed surface pattern were fabricated. The morphology, structure, and field electron emission properties of the fabricated structures were studied.

Gorbyk, P. P.; Dubrovin, I. V.; Dadykin, A. A.; Demchenko, Yu. A.

327

Migration of point defects and a defect pair in zinc oxide using the dimer method  

SciTech Connect

The migration mechanism and the minimum energy path of vacancies, interstitials and an interstitial-vacancy pair in zinc oxide have been studied by the dimer method. The in-plane and out-of-plane migrations of zinc and oxygen vacancies are found to be anisotropic. The kick-out mechanism is energetically preferred to zinc and oxygen interstitials that can easily migrate through the ZnO crystal lattice. In addition, the migration process of an interstitial-vacancy pair as a complex of an octahedral oxygen interstitial and a zinc vacancy is dominated by an oxygen interstitial/zinc vacancy successive migration. The energy barriers indicate that the existence of oxygen interstitial in the defect pair can promote the mobility of zinc vacancy, whereas the migration of oxygen interstitial is slowed down due to the presence of zinc vacancy. In the end, we show a possible migration path of the interstitial-vacancy pair that can be dissociated through a set of displacement movements.

Chen, Dong; Gao, Fei; Dong, Mingdong; Liu, Bo

2012-09-24

328

Kinetics of decolorization and mineralization of reactive azo dyes in aqueous solution by the UV\\/H 2O 2 oxidation  

Microsoft Academic Search

The photodegradation of three non hydrolysed reactive azo dyes (Reactive red 120, Reactive black 5, Reactive yellow 84) in aqueous solution was investigated in a laboratory-scale batch photoreactor equipped with an immersed low-pressure mercury lamp. Six different doses of hydrogen peroxide, at constant initial concentration of the substrate (100 mg\\/l) were used. The pseudo-first order rate constants have been calculated

Mariana Neamtu; Ilie Siminiceanu; Ayfer Yediler; Antonius Kettrup

2002-01-01

329

Highly flexible, transparent, and low resistance indium zinc oxide–Ag–indium zinc oxide multilayer anode on polyethylene terephthalate substrate for flexible organic light light-emitting diodes  

Microsoft Academic Search

The characteristics of indium zinc oxide (IZO)–Ag–IZO multilayer grown on a polyethylene terephthalate (PET) substrate were investigated for flexible organic light-emitting diodes (OLEDs). The IZO–Ag–IZO (IAI) multilayer anode exhibited a remarkably reduced sheet resistance of 6.93 ?\\/? and a high transmittance of 84.8%, despite the very thin thickness of the IZO (30 nm) layer. In addition, it was shown that electrical and

Sung-Woo Cho; Jin-A Jeong; Jung-Hyeok Bae; Jong-Min Moon; Kwang-Hyuk Choi; Soon Wook Jeong; No-Jin Park; Jang-Joo Kim; Se Hyung Lee; Jae-Wook Kang; Min-Su Yi; Han-Ki Kim

2008-01-01

330

Growth of high-quality, uniform c-axis-oriented zinc oxide nano-wires on a-plane sapphire substrate with zinc oxide templates  

Microsoft Academic Search

High-quality, vertically aligned zinc oxide (ZnO) nano-wires were grown by the vapour-transport method on (112¯0) (a-plane) sapphire substrate covered by a uniform ZnO nano-crystalline seed layer which was deposited in a preceding growth step via simple chemical vapour deposition. A thin layer of close-packed nano-seeds with an average size of 12nm was formed rapidly on the substrate by sublimation and

A. Reiser; V. Raeesi; G. M. Prinz; M. Schirra; M. Feneberg; U. Röder; R. Sauer; K. Thonke

2009-01-01

331

Effect of Zinc Oxide Film Deposition Position on the Characteristics of Zinc Oxide Thin Film Transistors Fabricated by Low-Temperature Magnetron Sputtering  

Microsoft Academic Search

We report on the effect of zinc oxide (ZnO) film deposition position on the characteristics of ZnO thin-film transistors (TFTs) fabricated by magnetron sputtering with no intentional heating of the substrate. We evaluate the properties of ZnO (channel semiconductor) films deposited at various positions with respect to the target position. We show that the film deposition at a position off-centered

Kazushige Takechi; Mitsuru Nakata; Toshimasa Eguchi; Shigeyoshi Otsuki; Hirotaka Yamaguchi; Setsuo Kaneko

2008-01-01

332

Correlation between Electrical Properties and Crystal c-Axis Orientation of Zinc Oxide Transparent Conducting Films  

NASA Astrophysics Data System (ADS)

Al-doped ZnO (AZO) was deposited on an undoped ZnO buffer layer at various deposition temperatures by RF-magnetron sputtering. We controlled the crystal c-axis orientation of AZO using the undoped ZnO buffer layer. With increasing deposition temperature of the undoped ZnO buffer layer, the alignment of the c-axis orientation of the AZO layer improved, and the sheet resistance of the AZO layer decreased. Comparing the electrical properties of the AZO layer with the c-axis orientation, the above correlation was confirmed. It is important to improve the alignment of the c-axis orientation for the improvement of the electrical properties of the AZO layer.

Maejima, Keigou; Shibata, Hajime; Tampo, Hitoshi; Matsubara, Koji; Niki, Shigeru

2012-10-01

333

The in vitro absorption of microfine zinc oxide and titanium dioxide through porcine skin.  

PubMed

Microfine metallic oxides such as titanium dioxide or zinc oxide have been found to be highly protective against harmful UV rays. Because their long-term use could potentially lead to health effects if significant amounts of these microfine metallic oxides would be absorbed through the skin, the in vitro absorption of microfine zinc oxide and titanium oxide in cosmetic formulations through porcine skin was investigated. In the experiments with a microfine zinc oxide formulation, the mean total recoveries of Zn were in the range from 102% to 107% of the total Zn applied. Virtually the total amount of applied Zn was recovered in the first five tape strips. The amounts of Zn found in the skin membrane and the receptor fluid were comparable in untreated, vehicle treated or test substance treated skin preparations. The absorption-time plots from diffusion cells treated with the vehicle did not differ from those treated with the ZnO containing formulation. In the experiments with microfine titanium dioxide formulations T-Lite SF-S and T-Lite SF, mean total recoveries of Ti ranged from 98% to 100% and 86% to 93% of the total Ti applied, respectively. Virtually the total amount of applied Ti could be removed from the skin surface by washing. The amounts of titanium found in the tape strips and skin preparations were in the order of the analytical determination limit. No Ti was found in the receptor fluid at any sampling time. The results show that neither zinc or titanium ions nor microfine zinc oxide or titanium dioxide particles were able to penetrate porcine stratum corneum. Therefore, from the absence of internal exposure we conclude that their use in sunscreens does not pose a health risk. PMID:16182508

Gamer, A O; Leibold, E; van Ravenzwaay, B

2005-09-21

334

Fabrication Process Assessment and Negative Bias Illumination Stress Study of Indium-Gallium-Zinc Oxide and Zinc-Tin Oxide Thin-Film Transistors  

NASA Astrophysics Data System (ADS)

Indium-gallium-zinc oxide (IGZO) and zinc-tin oxide (ZTO) are investigated for thin-film transistor (TFT) applications. Negative bias illumination stress (NBIS) is employed for electrical stability assessment. Unpassivated IGZO and ZTO TFTs suffer from severe NBIS instabilities. Zinc-tin-silicon oxide is found to be an effective passivation layer for IGZO and ZTO TFTs, significantly improving the NBIS stability. NBIS instabilities in unpassivated TFTs are attributed to an NBIS-induced desorption of chemisorbed oxygen from the channel layer top surface, exposing surface oxygen vacancies. A ZTSO layer protects the channel layer top surface from adsorbed gas interactions and also appears to reduce the density of oxygen vacancies. The best device architectures investigated with respect to TFT electrical performance are found to be staggered with aluminum electrodes for unpassivated TFTs and coplanar with ITO electrodes for ZTSO-passivated TFTs. Annealing in wet-O2 is not found to be effective for improving the performance of IGZO or ZTO TFTs or for reducing the post-deposition annealing temperature.

Hoshino, Ken

335

Atmospheric pressure based electrostatic spray deposition of transparent conductive ZnO and Al-doped ZnO (AZO) thin films: Effects of Al doping and annealing treatment  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) and Al-doped ZnO (AZO) thin films were prepared by electrostatic spray deposition method at atmospheric pressure followed by annealing. The effects of annealing and Al doping on the structural, electrical and optical properties of the films were investigated. The results show that films have random orientation with compact hexagonal wurtzite structure. It also implies that the annealing and the Al doping help to improve the electrical conductivity and optical properties as well. The minimum value of resistivity was 1.10 × 10-4 ? cm for 0.5 at. % AZO film and transmittance was greater than 96% in the visible region. The present value of resistivity is comparable to the lowest values for AZO films reported in open literatures. All the films prepared by this method have a good crystalline structure and homogenous surface. We proposed that the substitution of Al in the ZnO lattice has positive effects in terms of increasing the free electron concentration. At atmospheric pressure, the electrospraying method was confirmed to be suitable for the preparation of AZO films with low resistivity and high transmittance.

Mahmood, Khalid; Park, Seung Bin

2013-03-01

336

Corrosion electrochemical behavior of epoxy anticorrosive paints based on zinc molybdenum phosphate and zinc oxide  

Microsoft Academic Search

Electrochemical impedance spectroscopy (EIS) was applied as a principal tool to describe the efficiency of anticorrosive epoxy paints (primers) based on zinc molybdenum phosphate (ZMP) pigment. Steel-coated samples were exposed to a 0.5M NaCl solution. During the study the corrosion potential (Eoc) and Rp values also were monitored every 24h. It is discussed the incorporation of micronized ZnO (1?m) pigment

L. Veleva; J. Chin; B. del Amo

1999-01-01

337

The production of zinc by thermal dissociation of zinc oxide—solar chemical reactor design  

Microsoft Academic Search

We describe the design, fabrication, and preliminary test of a novel solar chemical reactor for conducting the thermal dissociation of ZnO into zinc and oxygen at above 2000 K. The reactor configuration features a windowed rotating cavity-receiver lined with ZnO particles that are held by centrifugal force. With this arrangement, ZnO is directly exposed to high-flux solar irradiation and serves

P. Haueter; S. Moeller; R. Palumbo; A. Steinfeld

1999-01-01

338

High quality ZnO:Al transparent conducting oxide films synthesized by pulsed filtered cathodic arc deposition  

SciTech Connect

Aluminum-doped zinc oxide, ZnO:Al or AZO, is a well-known n-type transparent conducting oxide with great potential in a number of applications currently dominated by indium tin oxide (ITO). In this study, the optical and electrical properties of AZO thin films deposited on glass and silicon by pulsed filtered cathodic arc deposition are systematically studied. In contrast to magnetron sputtering, this technique does not produce energetic negative ions, and therefore ion damage can be minimized. The quality of the AZO films strongly depends on the growth temperature while only marginal improvements are obtained with post-deposition annealing. The best films, grown at a temperature of about 200?C, have resistivities in the low to mid 10-4 Omega cm range with a transmittance better than 85percent in the visible part of the spectrum. It is remarkable that relatively good films of small thickness (60 nm) can be fabricated using this method.

Anders, Andre; Lim, Sunnie H.N.; Yu, Kin Man; Andersson, Joakim; Rosen, Johanna; McFarland, Mike; Brown, Jeff

2009-04-24

339

40 CFR 721.10107 - Naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo-naphthaleneyl]azo]-hydroxy...  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo-naphthaleneyl]azo]-hydroxy-[(methoxy-sulfophenyl)azo], metal salt (generic). 721.10107 Section 721.10107 Protection of...

2010-07-01

340

40 CFR 721.10107 - Naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo-naphthaleneyl]azo]-hydroxy...  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo-naphthaleneyl]azo]-hydroxy-[(methoxy-sulfophenyl)azo], metal salt (generic). 721.10107 Section 721.10107 Protection of...

2009-07-01

341

High-Performance Indium–Gallium–Zinc Oxide Thin-Film Transistors Based on Anodic Aluminum Oxide  

Microsoft Academic Search

Thin-film transistors (TFTs) based on indium- gallium-zinc oxide (IGZO) active layer and anodic aluminum oxide (Al2O3) gate dielectric were investigated. The anodic Al2O3 gate dielectric possesses low leakage current and relatively high dielectric constant. The IGZO TFT based on anodic Al2O3 shows a mobility of as high as 21.6 cm 2 \\/V · s, an on\\/off current ratio of as

Linfeng Lan; Junbiao Peng

2011-01-01

342

A study on the wet etching behavior of AZO (ZnO:Al) transparent conducting film  

NASA Astrophysics Data System (ADS)

This paper studies the wet etching behavior of AZO (ZnO:Al) transparent conducting film with tetramethylammonium hydroxide (TMAH). The optimum optoelectronic film is prepared first using designated RF power, film thickness and controlled annealing heat treatment parameters. The AZO film is then etched using TMAH etchant and AZ4620 photoresist with controlled etchant concentration and temperature to examine the etching process effect on the AZO film optoelectronic properties. The experimental results show TMAH:H 2O = 2.38:97.62 under 45 °C at the average etch rate of 22 nm/min as the preferred parameters. The activation energy drops as the TMAH concentration rises, while the etch rate increases along with the increase in TMAH concentration and temperature. After lithography, etching and photoresist removal, the conductivity of AZO film dramatically drops from 2.4 × 10 -3 ? cm to 3.0 × 10 -3 ? cm, while its transmittance decreases from 89% to 83%. This is due to the poor chemical stability of AZO film against AZ4620 photoresist, leading to an increase in surface roughness. In the photoresist postbaking process, carbon atoms diffused within the AZO film produce poor crystallinity. The slight decreases in zinc and aluminum in the thin film causes a carrier concentration change, which affect the AZO film optoelectronic properties.

Lin, Y. C.; Jian, Y. C.; Jiang, J. H.

2008-02-01

343

Improved electrical transport in Al-doped zinc oxide by thermal treatment  

Microsoft Academic Search

A postdeposition thermal treatment has been applied to sputtered Al-doped zinc oxide films and shown to strongly decrease the resistivity of the films. While high temperature annealing usually leads to deterioration of electrical transport properties, a silicon capping layer successfully prevented the degradation of carrier concentration during the annealing step. The effect of annealing time and temperature has been studied

F. Ruske; M. Roczen; K. Lee; M. Wimmer; S. Gall; D. Hrunski; B. Rech

2010-01-01

344

State-of-Charge Indicator for Zinc-Mercuric Oxide Batteries.  

National Technical Information Service (NTIS)

The feasibility of using a short duration, high current, constant voltage pulse charging technique to predict the state-of-charge of zinc-mercuric oxide cells and batteries was examined. The approach used in the study was (1) determine the test parameters...

D. C. Jones

1972-01-01

345

STUDY OF THE ANODIC OXIDATION PRODUCTS OF IRON-ZINC AND IRONCOPPER ALLOYS AT AMBIENT TEMPERATURE  

Microsoft Academic Search

The anodic oxidation products, at ambient temperature, of alloys with ; the formula 2 Fe-Zn and 2Fe-Cu were studied. The formation of zinc ferrite in ; the first case and of magnetite in the second is shown. (tr-auth);

Trautmann

1963-01-01

346

Zinc oxide semiconductor ceramic with nonlinear electric properties obtained by the coprecipitation method [for varistors  

Microsoft Academic Search

The paper presents a wet synthesis method of doped zinc oxide by coprecipitation in order to obtain a semiconductor ceramic with nonlinear electric properties. The manufacturing of varistor with high electric performances involves the using of high purity materials synthesised by successive purification processes at 99.995% purity level. The solutions purification that contains Zn2+ ions depends on type of starting

E. Andronescu; S. Jinga; C. Onose

2001-01-01

347

Engineering Evaluation of the Zinc-Mercuric Oxide Battery/Nickel-Cadmium Battery Hybrid System.  

National Technical Information Service (NTIS)

Appreciable improvements in the operating characteristics of the zinc mercuric oxide (Zn/HgO) primary battery were obtained at +20F on communication (transmit/receive) type loads by using it in parallel with a nickel cadmium (NiCd) secondary battery. Howe...

D. B. Wood

1974-01-01

348

Synthesis of zinc and cadmium naphthenates, catalysts for the radical-chain oxidation of alkylaromatic hydrocarbons  

SciTech Connect

The authors describe a method for the synthesis and purification of zinc and cadmium naphthenates and determine their respective catalytic effects in the oxidation of alkylaromatics by using isopropylbenzene as a test hydrocarbon. IR, NMR, and atomic emission spectroscopy are used to ascertain the reaction kinetics and yields and the structure of the participating reagents.

Kozlov, S.K.; Potekhin, V.M.

1986-08-20

349

A simple route for photocatalytic degradation of phenol in aqueous zinc oxide suspension using solar energy  

Microsoft Academic Search

In a laboratory study, the effectiveness of zinc oxide-mediated solar photocatalytic degradation of phenol was examined. The effect of various parameters like concentration of substrate, amount of photocatalyst, pH and irradiation time on the efficiency of photocatalytic degradation was studied. The demineralization of substrate was checked by Chemical Oxygen Demand (COD) reduction method. The photocatalytic degradation of phenol was found

S. K. Pardeshi; A. B. Patil

2008-01-01

350

Sulfur-Doped Zinc Oxide (ZnO) Nanostars: Synthesis and Simulation of Growth Mechanism.  

National Technical Information Service (NTIS)

We present a bottom-up synthesis, spectroscopic characterization, and ab initio simulations of star-shaped hexagonal zinc oxide (ZnO) nanowires. The ZnO nanostructures were synthesized by a low-temperature hydrothermal growth method. The cross-section of ...

J. Cho J. J. Simmons Q. Lin S. Yang Y. Cheng

2011-01-01

351

Synthesis of carbon and zinc oxide nanotubes and their applications in electronic devices  

Microsoft Academic Search

Nanostructured materials, including single and multiwalled carbon nanotubes (SWCNTs and MWCNTs), zinc oxide (ZnO) nanotubes (NTs) and graphene, have been successfully synthesized using chemical vapor deposition (CVD) or wet chemistry routines, and used to fabricate nanoelectronic and optoelectronic devices, including field effect transistors (FETs) and heterojunction solar cells. Both nanomaterials properties and devices performances have been characterized. Vertically aligned multiwalled

Kaikun Yang

2010-01-01

352

Correlation between surface area reduction and ultrasonic velocity in sintered zinc oxide powders  

Microsoft Academic Search

Specific surface area and longitudinal wave ultrasonic velocity were measured in zinc oxide (ZnO) powder compacts partially sintered to different pore fractions (P). A linear correlation was observed between the reduction in surface area and the increase in ultrasonic velocity at all P up to the onset of pore closure. During the initial stage of sintering, the ultrasonic velocity increased

L. P. Martin; M. Rosen

1997-01-01

353

Magnetism in polycrystalline cobalt-substituted zinc oxide  

Microsoft Academic Search

We present results of the preparation (by precursor decomposition), characterization (with x-ray diffraction, transmission electron microscopy, and dc magnetization measurements), and detailed computation (using density functional theory) of polycrystalline ZnO with up to 15% substitution of the zinc sites by divalent cobalt. The experimental results indicate the dominant magnetic interaction in well-characterized stoichiometric phases Zn1-xCoxO, x=0.05, 0.10, 0.15, is nearest-neighbor

A. S. Risbud; N. A. Spaldin; Z. Q. Chen; S. Stemmer; Ram Seshadri

2003-01-01

354

Surface Termination Effects on Zinc Oxide Quantum Dots  

Microsoft Academic Search

We investigate the effects of surface terminations on the optical properties of 2-6 nm ZnO quantum dots. Nanocrystals were grown by wet chemical synthesis in a short-chain alcohol solvent from zinc acetate and sodium hydroxide. Quenching of particle growth with various capping agents is necessary to maintain and enhance the unique characteristics of the nanocrystals. We reproduce results of previous

Steve Whitesell; Joe Spalenka; Christopher Jack; Cary Allen; Reuben Collins; Thomas Furtak

2007-01-01

355

AC Conductivity in Bismuth Oxide Doped Nickel-Zinc Ferrites  

Microsoft Academic Search

Substituted nickel zinc ferrites have been prepared in the composition series Ni0.5Zn0.5BixFe2.0-xO4 with x having values in the range 0.05 0.2. The electrical conductivity of the samples has been measured over the temperature range 150 to 300 K at frequencies ranging from 1 kHz to 1 MHz. The ac conductivity shows a variation of omegas where omega is the angular

Mrinal Pal; Pradip Brahma; Dipankar Chakravorty

1998-01-01

356

Octadecanethiol Island Formation on Single Crystal Zinc Oxide Surfaces  

NASA Astrophysics Data System (ADS)

Organic photovoltaic devices, containing ZnO nanorod electron acceptor arrays intercalated with organic polymers, could lead to low-cost solar cells. Surface modifications of ZnO with octadecanethiol (ODT) monolayers have been shown to improve charge transfer in such devices. The present work is an effort to understand these monolayers through studies of ODT on single crystals of ZnO with well-defined oxygen-terminated or zinc-terminated surfaces. Both bare and ODT- functionalized surfaces were characterized with atomic force microscopy, Fourier transform infrared spectroscopy, x-ray photoemission spectroscopy, and water contact angle measurements. ODT seemed to form islands of multilayers on zinc-terminated surfaces and islands of monolayers on oxygen- terminated surfaces. While ODT was expected to preferentially bond along defects and terraces on oxygen-terminated surfaces, this was not observed. ODT was also expected to more effectively bond to the zinc-terminated surface, which was observed. This work was supported by the National Science Foundation Division of Materials Research DMR-0606054, DMR-0907409, and the Renewable Energy Materials Research Science and Engineering Center at the Colorado School of Mines.

Yocom, Andrea; Collins, Reuben; Furtak, Thomas; Baker, Darick; Ohno, Timothy

2010-03-01

357

Methanol and formic acid oxidation in zinc electrowinning under process conditions  

Microsoft Academic Search

The possibility of using methanol or formic acid oxidation as the anode process in zinc electrowinning was examined. The activity\\u000a for methanol and formic acid oxidation on Pt coated high surface area electrodes was investigated over 36 h, at a current\\u000a density used in industry. The activity could be maintained at a constant potential level in a synthetic electrowinning electrolyte\\u000a if

M. Wesselmark; C. Lagergren; G. Lindbergh

2008-01-01

358

Electrochemical treatment of dilute cyanide solutions containing zinc complexes by oxidation at carbon felt (Sigratherm)  

Microsoft Academic Search

The electrochemical oxidation of dilute solutions containing cyanide complexes of zinc using a carbon felt anode is described. The composition of the solution was determined using stability constants for particular complexes. The application of a GFA5 electrode enables the oxidation of cyanides (10 mmol dm-3) in 99.2% at 0.7 V and 30 C (1.5 Qt). Under these conditions, the electrical

A. Socha; E. Ku?mierek; E. Chrze?cija?ska

2002-01-01

359

Fast All-Transparent Integrated Circuits Based on Indium Gallium Zinc Oxide Thin-Film Transistors  

Microsoft Academic Search

We describe the fabrication and characterization of visible transparent small-scale indium gallium zinc oxide (IGZO) integrated circuits. The IGZO channel and indium tin oxide (ITO) contacts and interconnects were pulsed laser deposited at room temperature. Low-temperature (200 ??C ) atomic-layer-deposited Al2O3 was used as the gate dielectric in bottom-gated thin-film transistors with field-effect mobility near 15 cm2\\/V??s. Logic inverters and

Arun Suresh; Patrick Wellenius; Vinay Baliga; Haojun Luo; Leda M. Lunardi; John F. Muth

2010-01-01

360

Oxidative stress and genotoxic effect of zinc oxide nanoparticles in freshwater snail Lymnaea luteola L.  

PubMed

Understanding the toxic effects of nanoparticles on aquatic organism is the biggest obstacle to the safe development of nanotechnology. However, little is known about the toxic mechanisms of zinc oxide nanoparticles (ZnONPs) in freshwater snail Lymnaea luteola (L. luteola). This study was designed to investigate the possible mechanisms of genotoxicity induced by ZnONPs in freshwater snail L. luteola. ZnONPs (32 ?g/ml) elicited a significant (p<0.01) reduction in glutathione (42.10% and 61.40%), glutathione-S-transferase (25.60% and 40.24%) and glutathione peroxidase (21.73% and 39.13%) with a concomitant increase in malondialdehyde level (54.50% and 57.14%; p<0.01) and catalase (34.88% and 52.56%; p<0.01) in digestive gland of L. luteola after 24 and 96 h exposure, respectively. However, a statistically significant (p<0.01) induction in DNA damage was observed by the comet assay in digestive gland cells treated with ZnONPs for 24 and 96 h. Thus, the results demonstrate that ZnONPs induce genotoxicity in digestive gland cells through oxidative stress. Freshwater snail L. luteola may be used as suitable test model for nanoecotoxicological studies in future. PMID:22917558

Ali, Daoud; Alarifi, Saud; Kumar, Sudhir; Ahamed, Maqusood; Siddiqui, Maqsood A

2012-08-08

361

The cytotoxic effects of titanium oxide and zinc oxide nanoparticles oh Human Cervical Adenocarcinoma cell membranes  

NASA Astrophysics Data System (ADS)

The importance of titanium dioxide (TiO2) and zinc oxide (ZnO), inorganic metal oxides nanoparticles (NPs) stems from their ubiquitous applications in personal care products, solar cells and food whitening agents. Hence, these NPs come in direct contact with the skin, digestive tracts and are absorbed into human tissues. Currently, TiO2 and ZnO are considered safe commercial ingredients by the material safety data sheets with no reported evidence of carcinogenicity or ecotoxicity, and do not classify either NP as a toxic substance. This study examined the direct effects of TiO2 and ZnO on HeLa cells, a human cervical adenocarcinonma cell line, and their membrane mechanics. The whole cell patch-clamp technique was used in addition to immunohistochemistry staining, TEM and atomic force microscopy (AFM). Additionally, we examined the effects of dexamethasone (DXM), a glucocorticoid steroid known to have an effect on cell membrane mechanics. Overall, TiO2 and ZnO seemed to have an adverse effect on cell membrane mechanics by effecting cell proliferation, altering cellular structure, decreasing cell-cell adhesion, activating existing ion channels, increasing membrane permeability, and possibly disrupting cell signaling.

Mironava, Tatsiana; Applebaum, Ariella; Applebaum, Eliana; Guterman, Shoshana; Applebaum, Kayla; Grossman, Daniel; Gordon, Chris; Brink, Peter; Wang, H. Z.; Rafailovich, Miriam

2013-03-01

362

The synthesis of zinc oxide nanoparticles from zinc acetylacetonate hydrate and 1-butanol or isobutanol.  

PubMed

ZnO nanoparticles of different sizes, from 20 to 200 nm in length, and morphologies, nanorods and coral-like structures, were synthesized via a simple one-pot synthesis by refluxing an oversaturated solution of zinc acetylacetonate hydrate in 1-butanol and isobutanol. On the basis of (1)H and (13)C NMR experiments, the reactions in both alcohols were found to proceed via the alcoholytic C-C cleavage of the acetylacetonate ligand, followed by the hydrolytic formation of the reactive Zn-OH intermediate from the water molecules present in the precursor hydrate species and/or those released during the condensation cycle. The zinc acetylacetonate conversion into ZnO in isobutanol is significantly slower than in the case when 1-butanol was used as both the medium and the reagent. FE-SEM studies showed that in 1-butanol the growth of the rod-shaped particles occurs via the agglomeration of ZnO primary particles that are less than 10 nm in size. The morphology of the particles formed in the isobutanol is time dependent, with the final coral-like structures developing from initially formed bundle-like structures. PMID:20347448

Ambrozic, Gabriela; Skapin, Sreco D; Zigon, Majda; Orel, Zorica Crnjak

2010-03-06

363

Oxidative stress in the pathogenesis of canine zinc-responsive dermatosis.  

PubMed

Zinc deficiency causes skin diseases both in humans and in animals. The underlying pathogenic mechanisms remain unclear, but a growing body of evidence indicates a role for zinc in skin protection against free radical-induced oxidative damage. The immunohistochemical expression of heat shock proteins (HSPs; Hsp27, Hsp72, Hsp73 and Hsp90), Cu/Zn superoxide dismutase (SOD), metallothionein (MT), Ki-67 antigen and active caspase-3 were evaluated in normal canine skin and in samples from eight dogs with zinc-responsive dermatosis. All investigated HSPs showed intense cytoplasmic immunostaining in the affected epidermis. Focal nuclear positivity of Hsp72 was also detected in keratinocytes. Although Cu/Zn SOD expression was similar to that observed in normal skin, MT immunoreactivity occurred in both the cytoplasm and the nucleus of basal cells in normal skin but was absent from the affected epidermis. Caspase-3 activation was also absent in the involved epidermis, which revealed a high Ki-67 index (a 3.5- to 9-fold increase compared with normal skin). These results support the hypothesis that cellular response to stress, particularly oxidative stress, is involved in the pathogenesis of skin lesions in canine zinc-responsive dermatosis. The lack of MT immunoreactivity in the affected epidermis may be indicative of low zinc levels, thus resulting in vulnerability to oxidative damage. In contrast, high expression levels of HSPs in skin during zinc deficiency may confer protection against a variety of dangerous stimuli, contributing to inhibition of apoptosis and to cell cycle regulation of proliferating keratinocytes. PMID:20723188

Romanucci, Mariarita; Bongiovanni, Laura; Russo, Anita; Capuccini, Silvia; Mechelli, Luca; Ordeix, Laura; Della Salda, Leonardo

2010-08-16

364

Physiology and biochemistry of reduction of azo compounds by Shewanella strains relevant to electron transport chain  

PubMed Central

Azo dyes are toxic, highly persistent, and ubiquitously distributed in the environments. The large-scale production and application of azo dyes result in serious environmental pollution of water and sediments. Bacterial azo reduction is an important process for removing this group of contaminants. Recent advances in this area of research reveal that azo reduction by Shewanella strains is coupled to the oxidation of electron donors and linked to the electron transport and energy conservation in the cell membrane. Up to date, several key molecular components involved in this reaction have been identified and the primary electron transportation system has been proposed. These new discoveries on the respiration pathways and electron transfer for bacterial azo reduction has potential biotechnological implications in cleaning up contaminated sites.

Gu, Ji-Dong

2010-01-01

365

Zinc supplementation in the elderly subjects: effect on oxidized protein degradation and repair systems in peripheral blood lymphocytes.  

PubMed

Aging has been associated with zinc deficiency, leading to chronic inflammation and subsequent oxidative stress, especially in the immune system. The increased oxidative stress provokes the accumulation of oxidized proteins, raising the problem of the efficacy of intracellular protein maintenance systems responsible for the elimination of oxidatively modified proteins. Our objective was to analyse the effect of zinc supplementation in the elderly on protein maintenance in peripheral blood lymphocytes. The status of the proteasome, which is in charge of oxidized protein degradation and the repair enzymes peptide methionine sulfoxide reductases, which can reverse methionine oxidation in proteins, were analysed on peripheral blood lymphocytes collected from 20 elderly subjects (age range between 59 and 85 years old) before and after zinc supplementation (10mg of zinc per day for 48+/-2 days). A decrease of oxidized protein content in zinc supplemented subjects was observed and was associated with an increase of expression levels and/or activities of proteasome and methionine sulfoxide reductases. Our results indicate that zinc treatment could enhance the anti-oxidative defences of peripheral blood lymphocytes by increasing the activities of protein maintenance systems responsible for the elimination of oxidatively modified proteins. PMID:18054192

Cabreiro, Filipe; Perichon, Martine; Jatje, Jolanta; Malavolta, Marco; Mocchegiani, Eugenio; Friguet, Bertrand; Petropoulos, Isabelle

2007-10-25

366

Zinc oxide and metal phthalocyanine based hybrid P-N junction diodes  

NASA Astrophysics Data System (ADS)

Hybrid p-n junction diode based on zinc oxide (ZnO) and metal phthalocyanine (MePc) has been demonstrated using highly conducting Al doped ZnO as transparent electrode. Three different MePcs: copper phthalocyanine, zinc phthalocyanine (ZnPc), and cobalt phthalocyanine are used as p-type layer in hybrid p-n junction. It is found that most desirable performance can be achieved in ZnO/ZnPc based hybrid p-n junction. The depletion region in hybrid p-n junctions has been measured using current-voltage and capacitance-voltage characteristics.

Singh, Budhi; Ghosh, Subhasis

2013-09-01

367

Influence of background concentration induced field on the emission rate signatures of an electron trap in zinc oxide Schottky devices  

Microsoft Academic Search

Various well-known research groups have reported points defects in bulk zinc oxide (ZnO) [ND (intrinsic): 1014-1017 cm-3] naming oxygen vacancy, zinc interstitial, and\\/or zinc antisite having activation energy in the range of 0.32-0.22 eV below conduction band. The attribution is probably based on activation energy of the level which seems not to be plausible in accordance with Vincent et al.,

Hadia Noor; P. Klason; S. M. Faraz; O. Nur; Q. Wahab; M. Willander; M. Asghar

2010-01-01

368

40 CFR 721.5930 - Phenylenebis[imino (chlorotriazinyl)imino(substituted naphthyl)azo(substituted phenyl)azo, sodium...  

Code of Federal Regulations, 2010 CFR

...imino (chlorotriazinyl)imino(substituted naphthyl)azo(substituted phenyl)azo, sodium salt (generic name). 721.5930 Section...imino (chlorotriazinyl)imino(substituted naphthyl)azo(substituted phenyl)azo, sodium salt...

2010-07-01

369

Effects of Zinc Supplementation on Plasma Copper/Zinc Ratios, Oxidative Stress, and Immunological Status in Hemodialysis Patients  

PubMed Central

Background: Patients undergoing hemodialysis (HD) have low plasma levels of zinc (Zn), high plasma levels of copper (Cu), and exhibit increased oxidative stress, inflammation, and immune abnormalities. We evaluated the effects of Zn supplementation on abnormal plasma Cu/Zn ratios and clinical outcomes in HD patients. Design and Methods: Patients on long-term HD with lower than normal plasma concentrations of Zn (< 80 mg/dL) were randomized to receive daily oral Zn supplements (n = 40) or no supplements (n = 25) for eight weeks. Age- and sex-matched healthy individuals served as a control group (n = 38). A number of clinical parameters were measured before and after the supplementation period. Results: Compared with healthy subjects, patients had significantly elevated plasma Cu concentrations and Cu/Zn ratios, as well as higher levels of oxidative stress and pro-inflammatory cytokines. Patients who received Zn supplements for eight weeks had higher plasma concentrations of Zn and lower concentrations of Cu, along with reduced Cu/Zn ratios, oxidative stress status, and inflammatory responses compared to patients who did not receive Zn. Patients receiving Zn also showed significantly higher percentages of CD4 and CD19 lymphocytes, and elevated CD4/CD8 ratios. Conclusions: Zn supplementation ameliorates abnormally high plasma Cu/Zn ratios and may reduce oxidative stress, improve inflammatory status, and maintain immune function in patients undergoing long-term HD.

Guo, Chih-Hung; Wang, Chia-Liang

2013-01-01

370

Surface Termination Effects on Zinc Oxide Quantum Dots.  

NASA Astrophysics Data System (ADS)

We investigate the effects of surface terminations on the optical properties of 2-6 nm ZnO quantum dots. Nanocrystals were grown by wet chemical synthesis in a short-chain alcohol solvent from zinc acetate and sodium hydroxide. Quenching of particle growth with various capping agents is necessary to maintain and enhance the unique characteristics of the nanocrystals. We reproduce results of previous work and expand on characterization of naked and surface terminated ZnO quantum dots. The nanoparticle properties were investigated by UV absorption spectrophotometry, photoluminescence, infrared spectroscopy, scanning electron microscopy , and atomic force microscopy techniques.

Whitesell, Steve; Spalenka, Joe; Jack, Christopher; Allen, Cary; Collins, Reuben; Furtak, Thomas

2007-03-01

371

Measurement of valence band structure in boron-zinc-oxide films by making use of ion beams  

SciTech Connect

Measurement of valence band structure in the boron-zinc oxide (BZO) films was developed using the secondary electron emission due to the Auger neutralization of ions. The energy distribution profile of the electrons emitted from boron-zinc-oxide films was measured and rescaled so that Auger self-convolution arose; thus, revealing the detailed structure of the valence band and suggesting that a high concentration of boron impurity in BZO films may enhance the transition of electrons and holes through the band gap from the valence to the conduction band in zinc oxide crystals; thereby improving the conductivity of the film.

Uhm, Han S.; Kwon, Gi C.; Choi, Eun H. [Department of Electrophysics, Kwangwoon University, Seoul 139-701 (Korea, Republic of)

2011-12-26

372

Nuclear microprobe investigation of the penetration of ultrafine zinc oxide into intact and tape-stripped human skin  

NASA Astrophysics Data System (ADS)

Ultrafine metal oxides, such as titanium dioxide and zinc oxide are widely used in cosmetic and health products like sunscreens. These oxides are potent UV filters and the small particle size makes the product more transparent compared to formulations containing coarser particles. In the present work the penetration of ultrafine zinc oxide into intact and tape-stripped human skin was investigated using nuclear microprobe techniques, such as proton induced X-ray spectroscopy and scanning transmission ion microscopy. Our results indicate that the penetration of ultrafine zinc oxide, in a hydrophobic basis gel with 48 h application time, is limited to the stratum corneum layer of the intact skin. Removing the stratum corneum partially or entirely by tape-stripping did not cause the penetration of the particles into the deeper dermal layers; the zinc particles remained on the surface of the skin.

Szikszai, Z.; Kertész, Zs.; Bodnár, E.; Major, I.; Borbíró, I.; Kiss, Á. Z.; Hunyadi, J.

2010-06-01

373

A Zinc Oxide Nanorod Ammonia Microsensor Integrated with a Readout Circuit on-a-Chip  

PubMed Central

A zinc oxide nanorod ammonia microsensor integrated with a readout circuit on-a-chip fabricated using the commercial 0.35 ?m complementary metal oxide semiconductor (CMOS) process was investigated. The structure of the ammonia sensor is composed of a sensitive film and polysilicon electrodes. The ammonia sensor requires a post-process to etch the sacrificial layer, and to coat the sensitive film on the polysilicon electrodes. The sensitive film that is prepared by a hydrothermal method is made of zinc oxide. The sensor resistance changes when the sensitive film adsorbs or desorbs ammonia gas. The readout circuit is used to convert the sensor resistance into the voltage output. Experiments show that the ammonia sensor has a sensitivity of about 1.5 mV/ppm at room temperature.

Yang, Ming-Zhi; Dai, Ching-Liang; Wu, Chyan-Chyi

2011-01-01

374

Investigation of phosphorus and arsenic as dopants in polycrystalline thin films of zinc oxide  

NASA Astrophysics Data System (ADS)

The use of implanted phosphorus and arsenic has been systematically investigated and compared with implanted boron as n-type dopants in thin films of polycrystalline zinc oxide. For a given heat-treatment schedule and without fluorine co-doping, the steady-state resistivity of the phosphorus-doped ZnO is found to be consistently lower than that of the boron-doped ZnO. Both are in turn lower than that of the arsenic-doped ZnO. A resistivity of 3 m? cm has been obtained for a phosphorus dose of 1016/cm2, if activated at 500 °C for 5 min in nitrogen. Direct exposure to an oxidizing ambience during a heat-treatment resulted in an increase in the resistivity of the phosphorus- or arsenic-doped zinc oxide thin films. However, the kinetics of the oxidation and reduction of arsenic in zinc oxide are found to be significantly slower than those of phosphorus or boron. Thin-film transistors with self-aligned phosphorus-doped source/drain regions and channel-lengths as short as 2 ?m have been realized and characterized.

Ye, Zhi; Wong, Man

2013-01-01

375

Effect of Annealing Temperature on the Surface Morphology and Electrical Properties of Aluminum Doped Zinc Oxide Thin Films Prepared by Sol-Gel Spin-Coating Method  

Microsoft Academic Search

Aluminum doped zinc oxide thin films were prepared through sol gel and spin coating technique from zinc acetate dihydrate and aluminum nitrate nanohydrate in alcoholic solution. The electrical properties and surface morphology study are investigated for the thin films annealed at 350~500 °C. Zinc oxide thin films deposited on glass and silicon substrates were characterized using electron microscopy (SEM) and

M. H. Mamat; S. Amizam; H. A. Rafaie; H. Hashim; A. Zain Ahmed; S. Abdullah; M. Rusop

2008-01-01

376

40 CFR 721.5930 - Phenylenebis[imino (chlorotriazinyl)imino(substituted naphthyl)azo(substituted phenyl)azo, sodium...  

Code of Federal Regulations, 2013 CFR

...naphthyl)azo(substituted phenyl)azo, sodium salt (generic name). 721.5930...naphthyl)azo(substituted phenyl)azo, sodium salt (generic name). (a) Chemical...naphthyl)azo (substituted phenyl) azo, sodium salt (PMN P-95-274) is...

2013-07-01

377

Fabrication and characterization of graphene oxide/zinc oxide nanorods hybrid  

NASA Astrophysics Data System (ADS)

This work presented a hybrid architecture of graphene oxide (GO)/ZnO nanorods (ZNs) with ZNs attached parallel onto GO sheets. ZNs were synthesized by refluxing zinc acetate dehydrate in methanol solution under basic conditions followed by surface modification of 3-aminopropyl triethoxysilane (ATS), and then the preformed ZNs were attached onto GO sheets by reaction of the amino groups on the outer wall of ZNs with the carboxyl groups on the GO surface. Transmission electron microscopy (TEM) image of the as-prepared hybrid reveals the morphology of the architecture of GO/ZNs hybrid. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) ultraviolet-visible (UV-vis) and fluorescence spectroscopy were also performed to characterize the structure and properties of the GO/ZNs hybrid. It was shown that ZNs maintained their initial morphology and crystallinity in the hybrid and the luminescence quenching of yellow-green emission of ZNs confirmed the electron transfer from excited ZnO to GO sheets.

Yang, Yang; Liu, Tianxi

2011-08-01

378

Atomic and molecular emissions of the laser-induced plasma during zinc and zinc oxide target ablation  

SciTech Connect

Optical emission spectroscopic investigations of the plasma produced during KrF excimer laser ablation of Zn and ZnO targets, in vacuum and in oxygen gas environment, are presented. The plume luminescence is mainly due to Zn excited atoms and ions, but the contribution of atomic and molecular oxygen, as well as of particulates, cannot be neglected. In particular, we detect emissions in the spectral regions around 380 and 530 nm, corresponding to the UV and green photo-luminescence bands of the zinc oxide. Moreover, we study the temporal evolution of atomic and ionic ejected species by space- and time-resolved spectroscopy and analyze the results by means of empirical models, in order to infer information about plasma dynamics.

Acquaviva, S.; D'Anna, E.; De Giorgi, M. L. [Department of Physics, University of Salento, via Arnesano, 73100 Lecce (Italy)

2007-10-01

379

Effect of Zinc and Nitric Oxide on Monocyte Adhesion to Endothelial Cells under Shear Stress  

PubMed Central

This study describes the effect of zinc on monocyte adhesion to endothelial cells under different shear stress regimens, which may trigger atherogenesis. Human umbilical vein endothelial cells were exposed to steady shear stress (15 dynes/cm2 or 1 dyne/cm2) or reversing shear stress (time average 1 dyne/cm2) for 24 hours. In all shear stress regimes, zinc deficiency enhanced THP-1 cell adhesion, while heparinase III reduced monocyte adhesion following reversing shear stress exposure. Unlike other shear stress regimes, reversing shear stress alone enhanced monocyte adhesion, which may be associated with increased H2O2 and superoxide together with relatively low levels of nitric oxide (NO) production. L-NG-Nitroarginine methyl ester (L-NAME) treatment increased monocyte adhesion under 15 dynes/cm2 and under reversing shear stress. After reversing shear stress monocyte adhesion dramatically increased with heparinase III treatment followed by a zinc scavenger. Static culture experiments supported the reduction of monocyte adhesion by zinc following endothelial cell cytokine activation. These results suggest that endothelial cell zinc levels are important for the inhibition of monocyte adhesion to endothelial cells, and may be one of the key factors in the early stages of atherogenesis.

Lee, Sungmun; Eskin, Suzanne G.; Shah, Ankit K.; Schildmeyer, Lisa A.; McIntire, Larry V.

2011-01-01

380

Zero photoelastic zinc tin phosphate glass without lead oxide.  

PubMed

The photoelastic constant (PEC) is evaluated for 15 zinc tin phosphate glasses in a series of xZnO-(67-x)SnO-33P(2)O(5) where x is 0-30 mol. % at 0.5-7 mol. % intervals. The phase retardation of polarized light, passing through a disk sample with applying various uniaxial loads, was measured for PEC determinations by using a frequency stabilized transverse Zeeman He-Ne laser as a polarized light source. The substitution of ZnO for SnO results in the increase of PEC from negative to positive values in the range of -1.43 and +1.45×10(-12) Pa(-1). The minimum PEC value of 0.04±0.02×10(-12) Pa(-1) was experimentally obtained in the 18.5 mol. % ZnO-48.5 mol. % SnO-33 mol. % P(2)O(5) glass. PMID:23073411

Yamamoto, Naoki; Saitoh, Akira; Takebe, Hiromichi

2012-10-15

381

The protective nature of passivation films on zinc: surface charge  

Microsoft Academic Search

The influence of oxide surface charge on the corrosion performance of zinc metals was investigated. Oxidised zinc species (zinc oxide, zinc hydroxychloride, zinc hydroxysulfate and zinc hydroxycarbonate) with chemical compositions similar to those produced on zinc during atmospheric corrosion were formed as particles from aqueous solution, and as passive films deposited onto zinc powder, and rolled zinc, surfaces. Synthesized oxides

Tim H Muster; Ivan S Cole

2004-01-01

382

Oxidation of zinc in alkaline solutions studied by electrochemical impedance spectroscopy  

SciTech Connect

Electrochemical dissolution and passivation reactions of zinc have been studied in 1.0 M KOH solutions by electrochemical impedance spectroscopy. Equivalent circuits have been worked out by simulating the impedance data and using the results to model the dissolution and passivation reactions. A Tafel plot constructed from the charge-transfer resistances provides an exchange current of 0.11 A/cm{sup 2} and an {alpha} value of 0.36 for zinc oxidation. The maximum rate of zinc oxidation is observed at about {minus}1.30 V vs. the Hg/HgO reference electrode as judged from the charge-transfer resistance minimum obtained from impedance measurements. A negative polarization resistance with a reverse semicircle on the Nyquist plot illustrates the transition process from an active to passive potential region at {minus}1.10 V. At high anodic over-potentials, the zinc electrode behaved as a semiconductor electrode due to a compact ZnO passive film formed on the electrode surface.

Cai, M.; Park, S.M. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Chemistry

1996-12-01

383

Electrochemistry of the Zinc-Silver Oxide System. Part 2: Practical Measurements of Energy Conversion Using Commercial Miniature Cells.  

ERIC Educational Resources Information Center

Summarizes the quantitative relationships pertaining to the operation of electrochemical cells. Energy conversion efficiency, cycle efficiency, battery power, and energy/power density of two types of zinc-silver oxide cells are discussed. (YP)

Smith, Michael J.; Vincent, Colin A.

1989-01-01

384

Electrochemistry of the Zinc-Silver Oxide System. Part 2: Practical Measurements of Energy Conversion Using Commercial Miniature Cells.  

ERIC Educational Resources Information Center

|Summarizes the quantitative relationships pertaining to the operation of electrochemical cells. Energy conversion efficiency, cycle efficiency, battery power, and energy/power density of two types of zinc-silver oxide cells are discussed. (YP)|

Smith, Michael J.; Vincent, Colin A.

1989-01-01

385

Sulfur Dioxide and Nitrogen Dioxide Adsorption on Zinc Oxide and Zirconium Hydroxide Nanoparticles and the Effect on Photoluminescence.  

National Technical Information Service (NTIS)

Nanoparticulate zinc oxide and micron-size zirconium hydroxide powders have been exposed to sulfur dioxide and nitrogen dioxide by flowing the gases, diluted with nitrogen, over powder samples. X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, a...

A. Mukherjee G. W. Peterson J. Im J. Singh J. E. Whitten

2012-01-01

386

Antibacterial Activity of Zinc Oxide-Coated Nanoporous Alumina.  

National Technical Information Service (NTIS)

Nanoporous alumina membranes, also known as anodized aluminum oxide membranes, are being investigated for use in treatment of burn injuries and other skin wounds. In this study, atomic layer deposition was used for coating the surfaces of nanoporous alumi...

J. Daniels M. R. Bayati P. E. Petrochenko S. Stafslien S. A. Skoog

2012-01-01

387

Porous zinc oxide films: Controlled synthesis, cytotoxicity and photocatalytic activity  

Microsoft Academic Search

The anodic oxidation technique was successfully carried out to fabricate porous ZnO films. Energy dispersive X-ray and scanning electron microscope indicated that the anodic oxidation time was the key factor to control surface pore density, which varied from 0.2±0.01% to 59.8±5.4%. The cytotoxicity study indicated that porous ZnO films displayed the pore density-dependent cytotoxicity on the metabolism and spread of

Hua-Jie Wang; Yuan-Yuan Sun; Ying Cao; Xue-Hong Yu; Xiao-Min Ji; Lin Yang

388

Effect of Triaryl Phosphate, Zinc and Zinc Borate on Fire Properties of High Impact Polystyrene and High Impact Polystyrene-Polyphenylene Oxide Blend (Modified-Polyphenylene Oxide  

Microsoft Academic Search

Samples of m-PPO (virgin and flame retarded) and high impact polystyrene blended with zinc and zinc borate (2ZnO·3B2O3·3.5H 2O), were pre pared. The effect of triaryl phosphate on the flame retardancy of PPO-HIPS in conjunction with zinc and zinc borate was studied.For polystyrene zinc borate shows some reduction in smoke generation. Zinc, however does not show any effect on smoke

Ramazan Benrashid; Gordon L. Nelson; Donald J. Ferm

1994-01-01

389

Influence of dietary carbohydrate on zinc-deficiency-induced changes in oxidative defense mechanisms and tissue oxidative damage in rats  

Microsoft Academic Search

The aim of this study was to determine the effect of dietary carbohydrate type on the expression of zinc (Zn) deficiency in\\u000a rats with respect to tissue oxidative damage and defense mechanisms. Rats were fed diets containing adequate (+Zn) or low\\u000a concentrations (-Zn) of Zn. Both fructose- and glucose-based diets were tested. Pair-fed controls were also studied to evaluate\\u000a changes

Sun H. Kim; Carl L. Keen

1999-01-01

390

Recent Developments in Aromatic Azo Polymers Research.  

National Technical Information Service (NTIS)

The photochemical and thermal cis to trans isomerization of aromatic azo groups covalently bonded within polymers and its practical consequences as well as some other recent applications are reviewed. The kinetics and mechanism of the isomerization of azo...

S. Xie A. Natansohn P. Rochon

1993-01-01

391

Growth of biepitaxial zinc oxide thin films on silicon (100) using yttria-stabilized zirconia buffer layer  

Microsoft Academic Search

In this work, an approach for integrating zinc oxide thin films with Si(100) substrates using an epitaxial tetragonal yttria-stabilized zirconia buffer layer is reported. Selected area electron diffraction measurements revealed the following epitaxial relationship: [110]YSZ||[100]Si and (001)YSZ||(001)Si. X-ray diffraction studies demonstrated that subsequent growth of the zinc oxide thin film on the yttria-stabilized zirconia buffer layer occurred with the following

Ravi Aggarwal; Chunming Jin; Punam Pant; J. Narayan; Roger J. Narayan

2008-01-01

392

Optical and electrical properties of zinc oxide thin films with low resistivity via Li–N dual-acceptor doping  

Microsoft Academic Search

Zinc oxide thin films with low resistivity have been deposited on glass substrates by Li–N dual-acceptor doping method via a modified successive ionic layer adsorption and reaction process. The thin films were systematically characterized via scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction, ultraviolet-visible spectrophotometry and fluorescence spectrophotometry. The resistivity of zinc oxide film was found to be

Daoli Zhang; Jianbing Zhang; Zhe Guo; Xiangshui Miao

2011-01-01

393

Characteristics of zinc oxide thin films prepared by r.f. magnetron-mode electron cyclotron resonance sputtering  

Microsoft Academic Search

Zinc oxide thin films were reactively deposited on glass substrates by r.f. magnetron-mode sputtering employing electron cyclotron resonance (ECR) plasma, and their crystallographic characteristics, electrical resistivity and optical properties were characterized. Single-phase zinc oxide thin films were deposited at very low gas pressures of 10?2 Pa in an O2 and Ar mixed gas atmosphere. They exhibited a c-axis orientation of

T. Inukai; M. Matsuoka; K. Ono

1995-01-01

394

Novel texturing method for sputtered zinc oxide films prepared at high deposition rate from ceramic tube targets  

Microsoft Academic Search

Sputtered and wet-chemically texture etched zinc oxide (ZnO) films on glass substrates are regularly applied as transparent front contact in silicon based thin film solar cells. In this study, chemical wet etching in diluted hydrofluoric acid (HF) and subsequently in diluted hydrochloric acid (HCl) on aluminum doped zinc oxide (ZnO:Al) films deposited by magnetron sputtering from ceramic tube targets at

E. Bunte; H. Zhu; J. Hüpkes; J. Owen

2011-01-01

395

Effects of channel stoichiometry and processing temperature on the electrical characteristics of zinc tin oxide thin-film transistors  

Microsoft Academic Search

Thin-film transistor (TFT) structures with zinc tin oxide channel layer are fabricated and electrically characterized; zinc tin oxide composition (Zn:Sn ratio) and post-deposition anneal temperature are varied so as to explore their effects on electrical performance. Channel mobility and turn-on voltage are extracted from measured electrical characteristics, thus mapping TFT performance (for the process and structure used here) across the

R. L. Hoffman

2006-01-01

396

Effect of morphology and crystallite size on solar photocatalytic activity of zinc oxide synthesized by solution free mechanochemical method  

Microsoft Academic Search

Zinc oxide crystallites were synthesized by two steps, solution free mechanochemical method. In order to obtain zinc oxide of different morphology and crystallite size, calcination temperature was varied from 400 to 900°C. These photocatalysts are then characterized by X-ray diffraction (XRD), Scanning Electron Micrograph (SEM), Energy dispersive X-ray spectra (EDXS), Fourier transform infrared spectra (FT-IR) and UV–Visible spectrophotometer. X-ray diffraction

S. K. Pardeshi; A. B. Patil

2009-01-01

397

A confocal microscopy study of the very early cellular response to oxidative stress induced by zinc phthalocyanine sensitization  

Microsoft Academic Search

Oxidative stress has been involved in several biological and pathological processes. Reactive oxygen species have been shown to play both beneficial and deleterious roles. The present work contributes to the understanding of the very early events of cellular response to oxidative stress. Oxidative stress was produced intracellularly by light activation of zinc phthalocyanine (ZnPc) at a light dose that did

Eleni Alexandratou; Dido Yova; Spyros Loukas

2005-01-01

398

Thermal oxidation of n-type ZnN films made by r f sputtering from a zinc nitride target, and their conversion into p-type films  

Microsoft Academic Search

Transparent p-type thin films, containing zinc oxide phases, have been fabricated from the oxidation of n-type zinc nitride films. The zinc nitride thin films were deposited by rf-magnetron sputtering from a zinc nitride target in pure N2 and pure Ar plasma. Films deposited in Ar plasma were conductive (resistivity 4.7×10?2 ? cm and carrier concentrations around 1020 cm?3) Zn-rich ZnxNy films of low

V. Kambilafka; P. Voulgaropoulou; S. Dounis; E. Iliopoulos; M. Androulidaki; V. Šály; M. Ruzinsky; E. Aperathitis

2007-01-01

399

High-performance transistors based on zinc tin oxides by single spin-coating process.  

PubMed

Films of zinc tin oxide (ZTO), grown from solutions with zinc acetate dehydrate and tin(II) 2-ethylhexanoate dissolved in 2-methoxyethanol, have been used to fabricate thin-film transistors in combination with solution-processed aluminum oxide as the gate insulator. And the nonhomogeneity of the single-layer ZTO films, caused by both ZTO film-substrate interaction and surface crystallization, has been studied, which is essential to achieve high performance transistors. In the bottom-contact thin-film transistor based on a Sn-rich layer of ZTO, a high mobility of 78.9 cm(2) V(-1) s(-1) in the saturation region has been obtained, with an on-to-off current ratio of 10(5) and a threshold gate voltage of 1.6 V. PMID:23210920

Zhao, Yunlong; Duan, Lian; Dong, Guifang; Zhang, Deqiang; Qiao, Juan; Wang, Liduo; Qiu, Yong

2012-12-18

400

Effect of annealing temperature on PL spectrum and surface morphology of zinc oxide thin films  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) thin films were produced by thermal oxidation of Zn layers (200 nm thickness) which were coated on Si (1 0 0) substrate by DC magnetron sputtering. In order to study the effect of annealing temperature on photoluminescence (PL) properties and the surface morphology of the ZnO samples, the annealing temperature range of 500-700 °C was employed. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) for investigation of surface morphology of the ZnO samples were carried out. The surface statistical characteristics of these ZnO thin films are then evaluated against data which outcome from AFM. SEM and AFM results indicated that the annealing temperature produces larger grains and rough surfaces at higher temperatures. The results of PL spectra represent an increase in interstitial zinc with increasing annealing temperature.

Zendehnam, A.; Mirzaee, M.; Miri, S.

2013-04-01

401

Formation of copper centers in a sensitized zinc oxide-polyvinyl alcohol system  

SciTech Connect

A substantial drop in the use of silver by the photographic industry may be brought about by replacing the conventional silver halides with low-silver and silver-free photographic materials. Of the silver-free photosensitive layers the most comparable to silver halogens in ultraviolet sensitivity is one comprising a dispersion of zinc oxide powder in polyvinyl alcohol (PVA), sensitized by components of a copper physical developer. This paper reports methods for forming latent image centers in a zinc oxide-PVA system sensitized by components of a copper physical developer. The derivatographic analysis was carried out on a Paulik Derivatograph. Electron spin resonance spectra were taken on a Bruker spectrometer at 77 K.

Gerleman, N.G.; Osipov, D.P.; Shagisultanova, G.A.

1988-11-10

402

The electronic structure of co-sputtered zinc indium tin oxide thin films  

SciTech Connect

Zinc indium tin oxide (ZITO) transparent conductive oxide layers were deposited via radio frequency (RF) magnetron co-sputtering at room temperature. A series of samples with gradually varying zinc content was investigated. The samples were characterized with x-ray and ultraviolet photoemission spectroscopy (XPS, UPS) to determine the electronic structure of the surface. Valence and conduction bands maxima (VBM, CBM), and work function were determined. The experiments indicate that increasing Zn content results in films with a higher defect rate at the surface leading to the formation of a degenerately doped surface layer if the Zn content surpasses {approx}50%. Furthermore, the experiments demonstrate that ZITO is susceptible to ultraviolet light induced work function reduction, similar to what was earlier observed on ITO and TiO{sub 2} films.

Carreras, Paz; Antony, Aldrin; Bertomeu, Joan [Departament de Fisica Aplicada i Optica, Universitat de Barcelona, 08028 Barcelona (Spain); Gutmann, Sebastian [Department of Chemistry, University of South Florida, Tampa, Florida 33620 (United States); Schlaf, Rudy [Department of Electrical Engineering, University of South Florida, Tampa, Florida 33620 (United States)

2011-10-01

403

Infrared spectroscopy of zinc oxide and magnesium nanostructures  

NASA Astrophysics Data System (ADS)

Impurities in ZnO nanoparticles and Mg nanorods were investigated. ZnO nanoparticles were prepared by a reaction of zinc acetate and sodium hydrogen carbonate. The presence and source of CO2 impurities in ZnO nanoparticles were studied by infrared (IR) spectroscopy. Isotopic substitution was used to verify the vibrational frequency assignment. Isochronal annealing experiments were performed to study the formation and stability of molecular impurities. The results indicate that the molecules are much more stable than CO 2 adsorbed on bulk ZnO surfaces. IR reflectance spectra of as-grown and hydrogen-annealed ZnO nanoparticles were measured at near-normal incidence. The as-grown particles were semi-insulating and showed reflectance spectra characteristic of insulating ionic crystals. Samples annealed in hydrogen showed a significant increase in electrical conductivity and free-carrier absorption. A difference was observed in the reststrahlen line shape of the conductive sample compared to that of the as-grown sample. The effective medium approximation was applied to model the reflectance and absorption spectra. The agreement between the experimental results and the model suggests that the nanoparticles have inhomogeneous carrier concentrations. Exposure to oxygen for several hours led to a significant decrease in carrier concentration, possibly due to the adsorption of negative oxygen molecules on the nanoparticle surfaces. Cu doped ZnO nanoparticles were prepared by using a zinc acetate/copper acetate precursor. The electronic transitions of Cu2+ ions were observed in the IR absorption spectrum at low temperatures. The high resistivity property of ZnO:Cu nanoparticles was observed. Magnesium hydroxide thin layers were formed by a chemical reaction between magnesium nanorods and water. IR spectroscopy showed hydroxide (OH) vibrational modes. The assignment was verified by reactions with heavy water which produced the expected OD vibrational frequency. A Fano interference was detected for hydroxide layers formed on metallic magnesium. For hydroxide layers on insulating magnesium hydride, however, the line shape was symmetric and no Fano resonance was observed. The results show that the hydroxide layer is thin such that the vibrational motion couples to the free electron continuum of the magnesium metal.

Hlaing Oo, Win Maw

404

From zinc nanowires to zinc oxide nanowires: a low substrate-temperature approach  

Microsoft Academic Search

We report here a simple two-step approach to produce ZnO nanowires, i.e. preparing Zn nanowires by evaporating Zn powder in a low vacuum and then oxidizing it to ZnO in air. This approach is very simple, catalyst free, and is capable of growing ZnO nanowires at low substrate temperatures; e.g. the substrate temperature for preparing Zn nanowires was ~200°C, and

Jingguo Liu; Zhengjun Zhang; Xin Su; Ye Zhao

2005-01-01

405

In situ monitoring of sputtered zinc oxide films for piezoelectric transducers  

Microsoft Academic Search

We report the application of in situ ellipsometry to monitor the growth by RF reactive sputtering of zinc oxide thin film piezoelectric transducers on silicon substrates. To establish the effect of substrate temperature on film quality and piezoelectric activity, films were grown at substrate temperatures of 100–300°C. Films of refractive index as high as 1.940 are achieved compared with refractive

N. K. Zayer; R. Greef; K. Rogers; A. J. C. Grellier; C. N. Pannell

1999-01-01

406

Substrate induced modifications in the structural and optical properties of zinc oxide thin films  

NASA Astrophysics Data System (ADS)

Zinc oxide thin films were grown on two different substrates (quartz and ITO coated glass) using RF sputtering technique. X-ray diffraction study confirms the formation of hexagonal wurtzite phase of the grown films. The optical properties of the thin films studied using UV-Vis spectroscopy technique show no change in the optical band gap of the grown films, however the enhancement in absorption edge is observed for the films grown on ITO coated glass substrate as compared to quartz.

Kumar, Parmod; Malik, Hitendra K.; Asokan, K.

2013-06-01

407

Copolymerization of Carbon Dioxide and Propylene Oxide with Zinc Catalysts Supported on Carboxyl-Containing Polymers  

Microsoft Academic Search

Polymer-supported zinc catalysts were prepared by the reaction of di-ethylzinc with polymers containing carboxyl groups. The catalysts were employed in the alternating copolymerization of carbon dioxide and propylene oxide to give poly(propylene carbonate) of high molecular weight. Copolymers of styrene and acrylic acid were shown to be better catalyst supports than poly(acrylic acid) and some other polymers. Maximum activity was

Li-Ban Chen; Hai-Sheng Chen; Jian Lin

1987-01-01

408

Carbothermic reduction of zinc sulfide in the presence of calcium oxide and lithium carbonate  

Microsoft Academic Search

The carbothermic reduction of zinc sulfide in the presence of calcium oxide and lithium carbonate was studied using a thermogravimetric\\u000a analysis system (TGA), an X-ray diffractometer (XRD), an atomic absorption spectrometer (AAS), a carbon and sulfur determinator\\u000a (CSD), an elemental analyzer (EA), a scanning electron microscope (SEM) and a surface area analyzer (SAA). Experimental results\\u000a revealed that the reaction rate

Y. C. Peng; C. I. Lin; H. K. Chen

2007-01-01

409

Aggregation of Zinc Protoporphyrin in Anodized Aluminum Oxide (AAO) Nanoporous Environments  

Microsoft Academic Search

The aggregation behavior of zinc protoporphyrin (ZnPP) inside nanoporous environments of anod- ized aluminum oxide (AAO) has been investigated through observation of the variation of UV\\/visible ab- sorption and emission spectra of the system. The Soret band in the absorption spectrum of ZnPP\\/AAO thin-film samples becomes much broader than that observed for ZnPP\\/THF solutions, and the relative in- tensity of

Jin-Shyong Lina; Yu-Chying Chen; Chien-Chon Chen; Eric Wei-Guang Diau; Tzeng-Feng Liu

410

Comparison of electrodeposited and sputtered intrinsic and aluminium-doped zinc oxide thin films  

Microsoft Academic Search

Intrinsic zinc oxide (i-ZnO) and aluminium-doped ZnO (ZnO:Al) are components of high-efficiency copper indium gallium diselenide solar cells. This paper examines both of these materials grown by two different techniques, namely radio frequency sputtering and electrodeposition (ED) for comparison and a better understanding. X-ray diffraction showed all materials to be polycrystalline and hexagonal (wurtzite) ZnO. Scanning electron microscopy indicated crystallites

J S Wellings; A P Samantilleke; P Warren; S N Heavens; I M Dharmadasa

2008-01-01

411

Biomimetic zinc oxide replica with structural color using butterfly (Ideopsis similis) wings as templates  

Microsoft Academic Search

Nano-structured colorful zinc oxide (ZnO) replicas were produced using the wings of the Ideopsis similis butterfly as templates. The ZnO replicas we obtained exhibit iridescence, which was clearly observed under an optical microscope (OM). Field emission scanning electron microscope analysis shows that all the microstructure details are maintained faithfully in the ZnO replica. A computer model was established to simulate

Wang Zhang; Di Zhang; Tongxiang Fan; Jian Ding; Jiajun Gu; Qixin Guo; Hiroshi Ogawa

2006-01-01

412

Mechanism of local stress release in armchair single-wall zinc oxide nanotube under tensile loading  

Microsoft Academic Search

The deformation mechanism of zinc oxide (ZnO) nanotube has been first examined by molecular dynamics. The result demonstrated\\u000a that ZnO nanotubes relax it excess strain via the phase transformation from an armchair structure to a fourfold-coordinated\\u000a structure, then to a zigzag structure, which is started by a slip deformation. In contrast to carbon, silicon carbide, and\\u000a boron nitride nanotubes, they

Wen-Jay Lee; Jee-Gong Chang; Shin-Pon Ju; Chia-Hung Lee

413

Long wet stand silver oxide-zinc cell tests (phase 1)  

Microsoft Academic Search

Specially built twenty ampere-hour, silver oxide-zinc cells were stored wet and charged at different temperatures for up to two years to determine capacity retention as a function of storage time and separator material. A total of 505 cells were fabricated using two to four layers of RAI P-2291 (40\\/60) or four layers of Fibrous Sausage Casing (FSC) as the separator

M. P. Dougherty

1975-01-01

414

Analysis of a conducting channel at the native zinc oxide surface  

Microsoft Academic Search

The electrical properties of high-resistivity zinc oxide (ZnO) bulk and epi-samples are strongly influenced by the sample ambient. Bulk samples that are highly resistive in ambient air can be reversibly transformed into a high conducting state under vacuum. As an explanation we suggest a conducting electron channel at the ZnO surface. Under vacuum this channel appears upon annealing. Exposure to

Oliver Schmidt; Arnd Geis; Peter Kiesel; Chris. G. Van de Walle; Noble M. Johnson; Andrey Bakin; Andreas Waag; Gottfried H. Döhler

2006-01-01

415

Modified Zinc Oxide for the Direct Synthesis of Propylene Carbonate from Propylene Glycol and Carbon dioxide  

Microsoft Academic Search

A series of modified zinc oxide catalysts were prepared and their catalytic activities were evaluated by the direct synthesis\\u000a of propylene carbonate from propylene glycol and carbon dioxide in the presence of acetonitrile, which acted as not only the\\u000a solvent but also the dehydrating reagent in the reaction. The reusability test indicated that the modified catalysts had the\\u000a high stability.

Shiyong Huang; Shuigang Liu; Junping Li; Ning Zhao; Wei Wei; Yuhan Sun

2007-01-01

416

High performance transparent thin film transistors based on indium gallium zinc oxide as the channel material  

Microsoft Academic Search

The fabrication of high performance amorphous indium gallium zinc oxide (IGZO) transparent thin film transistors (TTFT) and their bias stress stability is presented. N-channel enhancement mode devices were fabricated with an extracted field effect mobility of ~ 11-15 cm2 V-1s-1, on\\/off current ratios > 107, subthreshold gate voltage swing of 0.20-0.25 V\\/decade, low off-state currents and good saturation. Low and

A. Suresh; P. Wellenius; J. F. Muth

2007-01-01

417

Enhanced field emission characteristics of zinc oxide mixed carbon nano-tubes films  

Microsoft Academic Search

A composite material of Zinc oxide and carbon nano-tubes (ZnO–CNTs) paste was synthesized by mixing multi-wall CNTs, ZnO nano-grains and organic vehicles. The microstructures and the morphologies of screen-printed films were characterized by field-emission scanning electron microscope. Results show that ZnO flakes geometrically matched with CNTs by filling into the interspaces of CNTs or directly covering upon CNTs. The field

J. Y. Pan; C. C. Zhu; Y. L. Gao

2008-01-01

418

395-nm and 790-nm femtosecond laser ablation of aluminum-doped zinc oxide  

Microsoft Academic Search

We used 395-nm and 790-nm femtosecond laser pulses to deposit aluminum-doped zinc oxide films by pulsed laser deposition. Electrical resistivity of the films was lowered (5.6 x 104(Omega) cm) at 200 degree(s)C for the 395-nm laser pulses, while maintaining the optical transparency. In addition, the deposition rate increased six times. Optical emission was measured to compare the plumes generated by

Masayuki Okoshi; Kouji Higashikawa; Mitsugu Hanabusa

2000-01-01

419

Resistive Switching Characteristics of Sol–Gel Zinc Oxide Films for Flexible Memory Applications  

Microsoft Academic Search

Unipolar resistive switching devices are investigated for nonvolatile memory applications in a metal-insulator-metal structure in which the insulator layer is based on sol-gel-derived zinc oxide (ZnO) films prepared by a simple spin-coating process followed by thermal annealing. Fast programming ( les 50 ns) and a high off-to-on resistance ratio ( ges 104) is demonstrated. The influences on the switching behaviors

Sungho Kim; Hanul Moon; Dipti Gupta; Seunghyup Yoo; Yang-Kyu Choi

2009-01-01

420

Growth of zinc oxide films by a novel ultrasonic nebulization and pyrolysis method  

Microsoft Academic Search

Films of ZnO have been grown on various substrates by an ultrasonic nebulization and pyrolysis method. The resulting films were characterized by x-ray diffraction, optical and electrical measurements. They were found to be single-phase, homogeneous, and uniform in thickness. These films are comparable in quality to films prepared by more elaborate methods. Zinc oxide films are useful in a number

P. Wu; Y. M. Gao; R. Kershaw; K. Dwight; J. Baglio; A. Wold

1989-01-01

421

Fabrication of a TiO2-BDD heterojunction and its application as a photocatalyst for the simultaneous oxidation of an azo dye and reduction of Cr(VI).  

PubMed

A TiO2-boron doped diamond (TiO2-BDD) heterojunction was employed as a photocatalyst to simultaneously oxidize an azo dye C.I. reactive yellow 15 (RY15) and reduce hexavalent chromium (Cr(VI)). This heterojunction was fabricated first by depositing a BDD film on a Ti sheet in a hot filament chemical vapor deposition reactor, followed by covering a layer of TiO2 in a metal-organic chemical vapor deposition system. The morphology of this heterojunction was characterized by using a scanning electron microscope (SEM). X-ray diffraction (XRD), Raman spectroscopy, and current-voltage (I-V) measurement were used to characterize its structures. Additionally, the characterization of surface photovoltage showed that the TiO2-BDD heterojunction exhibited a higher photovoltage response and a better ability for charge separation than the photocatalyst of TiO2 directly deposited on a Ti sheet (TiO2-Ti). The photocatalytic experiments revealed that the kinetic constants for the oxidation of RY15 and the reduction of Cr(VI) were, respectively, increased by 85 and 71% when the photocatalyst of TiO2-Ti was replaced by the TiO2-BDD heterojunction. Meanwhile, a significant synergy was confirmed in the simultaneous oxidation of RY15 and reduction of Cr(VI). The enhanced photocatalytic ability of the TiO2-BDD composite could be attributed to the heterojunction. The possible photocatalytic mechanism was also discussed. PMID:18546724

Yu, Hongbin; Chen, Shuo; Quan, Xie; Zhao, Huimin; Zhang, Yaobin

2008-05-15

422

Weatherability and Leach Resistance of Wood Impregnated with Nano-Zinc Oxide  

NASA Astrophysics Data System (ADS)

Southern pine specimens vacuum-treated with nano-zinc oxide (nano-ZnO) dispersions were evaluated for leach resistance and UV protection. Virtually, no leaching occurred in any of the nano-ZnO-treated specimens in a laboratory leach test, even at the highest retention of 13 kg/m3. However, specimens treated with high concentrations of nano-ZnO showed 58-65% chemical depletion after 12 months of outdoor exposure. Protection from UV damage after 12 months exposure is visibly obvious on both exposed and unexposed surfaces compared to untreated controls. Graying was markedly diminished, although checking occurred in all specimens. Nano-zinc oxide treatment at a concentration of 2.5% or greater provided substantial resistance to water absorption following 12 months of outdoor exposure compared to untreated and unweathered southern pine. We conclude that nano-zinc oxide can be utilized in new wood preservative formulations to impart resistance to leaching, water absorption and UV damage of wood.

Clausen, Carol A.; Green, Frederick; Nami Kartal, S.

2010-09-01

423

Gaseous species as reaction tracers in the solvothermal synthesis of the zinc oxide terephthalate MOF-5.  

PubMed

Gaseous species emitted during the zinc oxide/zinc hydroxide 1,4-benzenedicarboxylate metal organic framework synthesis (MOF-5, MOF-69c) have been used to investigate the reaction scheme that leads to the framework creation. Changes of the gas-phase composition over time indicate that the decomposition of the solvent diethylformamide occurs at least via two competing reaction pathways that can be linked to the reaction's overall water and pH management. From isotope exchange experiments, we deduce that one of the decomposition pathways leads to the removal of water from the reaction mixture, which sets the conditions when the synthesis of an oxide-based (MOF-5) instead of an hydroxide-based MOF (MOF-69c) occurs. A quantitative account of most reactants and byproducts before and after the MOF-5/MOF-69c synthesis is presented. From the investigation of the reaction intermediates and byproducts, we derive a proposal of a basic reaction scheme for the standard synthesis zinc oxide carboxylate MOFs. PMID:17455926

Hausdorf, Steffen; Baitalow, Felix; Seidel, Jürgen; Mertens, Florian O R L

2007-04-25

424

Influence of particle size of nano zinc oxide on the controlled delivery of Amoxicillin  

NASA Astrophysics Data System (ADS)

A great effort has been exerted to develop drug carriers aiming at satisfying the requirements, such as safety, greater efficiency, predictable therapeutic response, and prolonged release period. The present study aims at developing the use of zinc oxide nanoparticles as a carrier as a function of particle size for amoxicillin drug delivery system. The amoxicillin-loaded zinc oxide nanoparticles have a good antibacterial activity against infectious Gram-positive and Gram-negative bacteria. Zinc oxide nanoparticles have been prepared by wet chemical precipitation method varying the pH values. Particle size and morphology of the as-prepared ZnO powders are characterized by X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscope. Drug loading, in vitro drug release and antibacterial activity have been analyzed. Maximum zone of inhibition is observed for Staphylococcus epidermis. The results show that inhibitory efficacy of drug-loaded ZnO nanoparticles is very much dependent on its chosen concentration, drug loading, and size.

Palanikumar, L.; Ramasamy, S.; Hariharan, G.; Balachandran, C.

2013-10-01

425

Enhanced zinc oxide and graphene nanostructures for electronics and sensing applications  

NASA Astrophysics Data System (ADS)

Zinc oxide and graphene nanostructures are important technological materials because of their unique properties and potential applications in future generation of electronic and sensing devices. This dissertation investigates a brief account of the strategies to grow zinc oxide nanostructures (thin film and nanowire) and graphene, and their applications as enhanced field effect transistors, chemical sensors and transparent flexible electrodes. Nanostructured zinc oxide (ZnO) and low-gallium doped zinc oxide (GZO) thin films were synthesized by a magnetron sputtering process. Zinc oxide nanowires (ZNWs) were grown by a chemical vapor deposition method. Field effect transistors (FETs) of ZnO and GZO thin films and ZNWs were fabricated by standard photo and electron beam lithography processes. Electrical characteristics of these devices were investigated by nondestructive surface cleaning, ultraviolet irradiation treatment at high temperature and under vacuum. GZO thin film transistors showed a mobility of ˜5.7 cm2/V·s at low operation voltage of <5 V and a low turn-on voltage of ˜0.5 V with a sub threshold swing of ˜85 mV/decade. Bottom gated FET fabricated from ZNWs exhibit a very high on-to-off ratio (˜106) and mobility (˜28 cm2/V·s). A bottom gated FET showed large hysteresis of ˜5.0 to 8.0 V which was significantly reduced to ˜1.0 V by the surface treatment process. The results demonstrate charge transport in ZnO nanostructures strongly depends on its surface environmental conditions and can be explained by formation of depletion layer at the surface by various surface states. A nitric oxide (NO) gas sensor using single ZNW, functionalized with Cr nanoparticles was developed. The sensor exhibited average sensitivity of ˜46% and a minimum detection limit of ˜1.5 ppm for NO gas. The sensor also is selective towards NO gas as demonstrated by a cross sensitivity test with N2, CO and CO2 gases. Graphene film on copper foil was synthesized by chemical vapor deposition method. A hot press lamination process was developed for transferring graphene film to flexible polymer substrate. The graphene/polymer film exhibited a high quality, flexible transparent conductive structure with unique electrical-mechanical properties; ˜88.80% light transmittance and ˜1.1742O/sq k sheet resistance. The application of a graphene/polymer film as a flexible and transparent electrode for field emission displays was demonstrated.

Verma, Ved Prakash

426

Zinc Oxide Surge Arresters and HVDC 125kV-upgrade 500kV Converter Stations  

NASA Astrophysics Data System (ADS)

Gapless Metal (Zinc) Oxide Surge Arresters for a.c. systems contribute to the insulation co-ordination based on the suppression of lightning surges and switching surges. These gapless metal oxide surge arresters using ZnO elements are effective to HVDC systems. This paper describes basic characteristics of ZnO (zinc oxide) elements for d.c. systems and applications of gapless surge arresters to HVDC 125kV frequency converters, HVDC 250kV, upgrade HVDC 500kV converter stations, and HVDC 500kV cables of Japan through the experience of developments and applications of gapless metal oxide surge arresters.

Shirakawa, Shingo; Kobayashi, Takayuki; Matsushita, Yoshinao; Sakai, Takehisa; Suzuki, Hironori; Ozaki, Yuzo

427

Solution-processed indium gallium zinc oxide thin-film transistors with infrared irradiation annealing  

NASA Astrophysics Data System (ADS)

In this paper, an infrared annealing method was proposed for solution-processed indium gallium zinc oxide films. The optimized IGZO thin-film transistors (TFTs) exhibited a field-effect mobility of 2.04 cm2 (Vs)-1, on-off current ratio of 1.52×106 and subthreshold swing of 0.84 V/dec. Spectroscopic analysis confirmed that the infrared irradiation could enhance the removal of organic species and dehydroxylation. The results suggest that infrared annealing method is a potential process for low-temperature preparation of solution-processed oxide semiconductor layers and dielectric layers, and can be applied to the fabrication of TFT devices.

Pu, Haifeng; Zhou, Qianfei; Yue, Lan; Zhang, Qun

2013-10-01

428

Influence of aromatic substitution patterns on azo dye degradability by Streptomyces spp. and Phanerochaete chrysosporium.  

PubMed Central

Twenty-two azo dyes were used to study the influence of substituents on azo dye biodegradability and to explore the possibility of enhancing the biodegradabilities of azo dyes without affecting their properties as dyes by changing their chemical structures. Streptomyces spp. and Phanerochaete chrysosporium were used in the study. None of the actinomycetes (Streptomyces rochei A10, Streptomyces chromofuscus A11, Streptomyces diastaticus A12, S. diastaticus A13, and S. rochei A14) degraded the commercially available Acid Yellow 9. Decolorization of monosulfonated mono azo dye derivatives of azobenzene by the Streptomyces spp. was observed with five azo dyes having the common structural pattern of a hydroxy group in the para position relative to the azo linkage and at least one methoxy and/or one alkyl group in an ortho position relative to the hydroxy group. The fungus P. chrysosporium attacked Acid Yellow 9 to some extent and extensively decolorized several azo dyes. A different pattern was seen for three mono azo dye derivatives of naphthol. Streptomyces spp. decolorized Orange I but not Acid Orange 12 or Orange II. P. chrysosporium, though able to transform these three azo dyes, decolorized Acid Orange 12 and Orange II more effectively than Orange I. A correlation was observed between the rate of decolorization of dyes by Streptomyces spp. and the rate of oxidative decolorization of dyes by a commercial preparation of horseradish peroxidase type II, extracellular peroxidase preparations of S. chromofuscus A11, or Mn(II) peroxidase from P. chrysosporium. Ligninase of P. chrysosporium showed a dye specificity different from that of the other oxidative enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)

Pasti-Grigsby, M B; Paszczynski, A; Goszczynski, S; Crawford, D L; Crawford, R L

1992-01-01

429

Doped nanostructured zinc oxide films grown by electrodeposition.  

PubMed

ZnO thin films doped with either In or Al are n-type oxide materials of interest for application in electronic devices and thin-film solar cells. In this work, the doped ZnO films were electrodeposited at 80 degrees C from an aqueous solution on polycrystalline conductive Indium Tin Oxide covered glass substrates. The incorporation of the dopants into the ZnO film has been verified by energy dispersive X-ray spectrum, X-Ray diffraction and optical transmission analysis. The optical and surface structure properties of the ZnO doped films are strongly affected by the In and Al concentrations in the electrodeposition solution as evidenced by optical transmission and reflection measurements, and scanning electron microscopy. PMID:20352804

Donderis, V; Orozco, J; Cembrero, J; Curiel-Esparza, J; Damonte, L C; Hernández-Fenollosa, M A

2010-02-01

430

Electrical effect of titanium diffusion on amorphous indium gallium zinc oxide  

SciTech Connect

In this work, thermal diffusion phenomenon of Ti into amorphous indium gallium zinc oxide ({alpha}-IGZO) was carefully investigated with secondary ion mass spectroscopy, I-V, and R{sub s} measurement systems and HSC chemistry simulation tool. According to the experimental and simulated results, the diffused Ti atoms were easily oxidized due to its lowest oxidation free energy. Since oxygen atoms were decomposed from the {alpha}-IGZO during the oxidation of Ti, the number of oxygen vacancies working as electron-donating sites in {alpha}-IGZO was dramatically increased, contributing to the decrease of resistivity ({rho}) from 1.96 {Omega} cm (as-deposited {alpha}-IGZO) to 1.33 Multiplication-Sign 10{sup -3}{Omega} cm (350 Degree-Sign C annealed {alpha}-IGZO).

Choi, Seung-Ha [School of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Development Group of Oxide Semiconductor, Samsung Display, Yongin 446-711 (Korea, Republic of); Jung, Woo-Shik [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Park, Jin-Hong [School of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

2012-11-19

431

Acceptor conductivity in bulk zinc oxide (0001) crystals  

NASA Astrophysics Data System (ADS)

ZnO is a promising wide bandgap semiconductor. Its renowned and prominent properties as its bandgap of 3.37eV at 4.2K; its very high excitonic binding energy, 60meV; its high melting temperature, 2248K constitute the basis for the recently renewed and sustained scientific interests in the material. In addition to the foregoing, the availability of bulk substrates of industrially relevant sizes provides important opportunities such as homoepitaxial deposition of the material which is a technological asset in the production of efficient optoelectronic and electronic devices. The nemesis of wide bandgap materials cannot be more exemplified than in ZnO. The notorious limitation of asymmetric doping and the haunting plague of electrically active point defects dim the bright future of the material. In this case, the search for reliable and consistent acceptor conductivity in bulk substrates has been hitherto, unsuccessful. In the dissertation that now follows, our efforts have been concerted in the search for a reliable acceptor. We have carefully investigated the science of point defects in the material, especially those responsible for the high donor conductivity. We also investigated and herein report variety of techniques of introducing acceptors into the material. We employ the most relevant and informative characterization techniques in verifying both the intended conductivity and the response of intrinsic crystals to variation in temperature and strain. And finally we explain deviations, where they exist, from ideal acceptor characteristics. Our work on reliable acceptor has been articulated in four papers. The first establishing capacitance based methods of monitoring electrically active donor defects. The second investigates the nature of anion acceptors on the oxygen sublattice. A study similar to the preceding study was conducted for cation acceptors on the zinc sublattice and reported in the third paper. Finally, an analysis of the response of the crystal to hydrostatic strain and its recovery when such strain enforces a collapse of its crystallinity is reported in the fourth paper. For the sake of brevity and the need to be concise, our supplementary investigations on extrinsic donor conductivity is deferred to other journal publications.

Adekore, Bababunmi Tolu

432

Copper-zinc-cobalt-aluminium-chromium hydroxycarbonates and mixed oxides  

SciTech Connect

Hydroxycarbonate precursors with different Cu/Zn/Co/Al/Cr atomic ratios were preared by coprecipitation of the metal nitrates with a stoichiometric amount of NaHCO{sub 3} under controlled conditions of temperature, stirring, and pH. Cu-Zn-Co-Al-Cr mixed oxides were obtained by decomposition of the precursors at different temperatures (623, 723, and 973 K in air). The characterization has been performed by X-ray powder diffraction (XRPD), diffuse reflectance spectroscopy in the UV-VIS-NIR region (DRS), thermal analysis (TGA/DTA), BET surface area determination, and measurements of magnetic susceptibility.

Morpurgo, S.; Jacono, M.L.; Porta, P. [Universita La Sapienza, Rome (Italy)

1996-03-01

433

Lung injury in guinea pigs caused by multiple exposures to submicron zinc oxide mixed with sulfur dioxide in a humidified furnace  

Microsoft Academic Search

Sulfur dioxide, water vapor, and ultrafine particles rich in oxides of zinc and other surface?deposited trace elements are important products of coal combustion. In order to study the toxicity of zinc oxide generated under conditions simulating combustion, guinea pigs were exposed in a nose?only apparatus for 3 h on 6 consecutive days to 6 mg\\/m of submicron zinc oxide particles

Michael W. Conner; Hua F. Lam; Adrianne E. Rogers; Shelley Fitzgerald; Mary O. Amdur

1985-01-01

434

Silver ions induce oxidative stress and intracellular zinc release in human skin fibroblasts.  

PubMed

Silver compounds used as topical antimicrobial agents are known to exert toxic effects on skin cells. The aim of this study was to investigate whether the toxicity of silver ions, in analogy to other transition metal ions, depends on pro-oxidant effects. We treated human skin fibroblasts with concentrations of AgNO(3) not affecting cell proliferation, mitochondrial activity, or cell viability and found that Ag(+) strongly increases the production of reactive oxygen species, including superoxide anion radicals. These effects correspond to a strong decrease in intracellular reduced glutathione and to an increased susceptibility to H(2)O(2)-induced cell death. In addition, AgNO(3) down-regulates the expression of antioxidant genes such as the transcription factor Nrf2 and its target gene glutamate-cysteine ligase catalytic subunit. Furthermore Ag(+) induces a transient intracellular zinc release and increases the mRNA and protein expression of the zinc-binding protein metallothionein by activating the metal-responsive transcription factor 1, as verified by RNA interference. In conclusion, we show for the first time that Ag(+) induces oxidative stress and affects intracellular zinc homeostasis in human skin fibroblasts. The understanding of the mechanism involved in silver toxicity might contribute to new strategies for managing the therapy of skin infections. PMID:19733233

Cortese-Krott, Miriam M; Münchow, Meike; Pirev, Elvis; Hessner, Florian; Bozkurt, Ahmed; Uciechowski, Peter; Pallua, Norbert; Kröncke, Klaus-D; Suschek, Christoph V

2009-09-03

435

Preparation of ciprofloxacin-coated zinc oxide nanoparticles and their antibacterial effects against clinical isolates of Staphylococcus aureus and Escherichia coli.  

PubMed

In the present research study, ciprofloxacin-coated zinc oxide nanoparticles were prepared using a precipitation method. The nature of interactions between zinc oxide nanoparticles and ciprofloxacin (CAS 85721-33-1) was studied by Fourier transform infrared spectroscopy. The results show that the carbonyl group in ciprofloxacin is actively involved in forming chemical--rather than physical--bonds with zinc oxide nanoparticles. Also the antibacterial activity of free zinc oxide nanoparticles and ciprofloxacin-coated zinc oxide nanoparticles have been evaluated against different clinical isolates of Staphylococcus aureus and Escherichia coli. The free zinc oxide nanoparticles did not show potent antibacterial activity against all test strains. In contrast, only the low concentrations of ciprofloxacin-coated zinc oxide nanoparticles (equivalent to the sub-minimum inhibitory concentrations of pure ciprofloxacin) considerably enhanced the antibacterial activity of zinc oxide nanoparticles against different isolates of Staphylococcus aureus and Escherichia coli (4 to 32 fold increase). The result is of particular value, since it demonstrates that, by using biocompatible zinc oxide nanoparticles in combination therapy, lower amounts of antibiotics may be needed. PMID:21950151

Seif, Sepideh; Kazempour, Zahra Bahri; Pourmand, Mohammad Reza; Shahverdi, Hamid Reza; Amanlou, Massoud; Bazl, Roya; Nazari, Zeynab Esmail; Shahverdi, Ahmad Reza

2011-01-01

436

Bio-Fabrication of zinc oxide nanoparticles using leaf extract of Parthenium hysterophorus L. and its size-dependent antifungal activity against plant fungal pathogens  

NASA Astrophysics Data System (ADS)

The study reports the synthesis and characterization of zinc oxide nanoparticles from weed plant by a novel method. The aim of this work is to synthesize zinc oxide nanoparticles from Parthenium hysterophorus L. by inexpensive, ecofriendly and simple method. Highly stable, spherical and hexagonal zinc oxide nanoparticles were synthesized by using different concentrations of 50% and 25% parthenium leaf extracts. Both the concentrations of the leaf extract act as reducing and capping agent for conversion of nanoparticles. Formation of zinc oxide nanoparticles have been confirmed by UV-Vis absorption spectroscopy, X-ray diffraction (XRD), Fourier trans-form infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis with energy dispersive X-ray analysis (EDX). SEM, TEM and EDX analysis reveals that spherical and hexagonal zinc oxide nanoparticle sizes were 27 ± 5 nm and 84 ± 2 nm respectively and chemical composition of zinc oxide were present. We synthesized different sized zinc oxide nanoparticles and explored the size-dependent antifungal activity against plant fungal pathogens. Highest zone of inhibition was observed in 25 ?g/ml of 27 ± 5 nm size zinc oxide nanoparticles against Aspergillus flavus and Aspergillus niger. Parthenium mediated zinc oxide nanoparticles were synthesized and proved to be good antifungal agents and environment friendly.

Rajiv, P.; Rajeshwari, Sivaraj; Venckatesh, Rajendran

2013-08-01

437

Preparation, characterization and properties of novel covalently surface-functionalized zinc oxide nanoparticles  

NASA Astrophysics Data System (ADS)

Novel covalently surface-modified zinc oxide (ZnO) nanoparticles (NP) (ZHIE) were successfully prepared, which have organic chains composed of hydrophilic amide and urethane linkages, and terminal amino groups on the surfaces, using zinc acetate monohydrate. FTIR spectroscopy, X-ray analysis and TEM observation suggested that the resultant ZHIE NPs have the mean sizes of about 10 nm in diameters, the organic chains linking the amino groups in the terminals and wurtzite crystal structure. UV-vis absorption spectrum of the ZHIE NPs in methanol showed maximum absorption band at 348 nm, supporting the TEM observations. Photoluminescent spectrum measurements depicted that the ZHIE NPs show broad visible emission band on the basis of trapped-electron emission. Cytotoxicity and phagocytosis assays suggested that the ZHIE NPs are noncytotoxic, and the ZHIE-labeled zymosan particles derived by conjugation of the ZHIE NPs with zymosan are internalized into the cells and generate fluorescence based on the ZHIE NPs.

Sato, Moriyuki; Harada, Hajime; Morito, Shigekazu; Fujita, Yasuhisa; Shimosaki, Shunsuke; Urano, Takeshi; Nakamura, Morihiko

2010-05-01

438

Morphological impact of zinc oxide layers on the device performance in thin-film transistors.  

PubMed

Zinc oxide thin-films are prepared either by spin coating of an ethanolic dispersion of nanoparticles (NP, diameter 5 nm) or by spray pyrolysis of a zinc acetate dihydrate precursor. High-resolution electron microscopy studies reveal a monolayer of particles for the low temperature spin coating approach and larger crystalline domains of more than 30 nm for the spray pyrolysis technique. Thin-film transistor devices (TFTs) based on spray pyrolysis films exhibit higher electron mobilities of up to 24 cm2 V(-1) s(-1) compared to 0.6 cm2 V(-1) s(-1) for NP based TFTs. These observations were dedicated to a reduced number of grain boundaries within the transistor channel. PMID:21116548

Faber, Hendrik; Klaumünzer, Martin; Voigt, Michael; Galli, Diana; Vieweg, Benito F; Peukert, Wolfgang; Spiecker, Erdmann; Halik, Marcus

2010-11-29

439

Hot gas desulfurization with sorbents containing oxides of zinc, iron, vanadium and copper  

SciTech Connect

The main objective of this research is to evaluate the desulfurization performance of novel sorbents consisting of different combinations of zinc, iron, vanadium and copper oxides; and to develop a sorbent which can reduce H{sub 2}S levels to less than 1 ppmv, which can stabilize zinc, making operations above 650{degrees}C possible, and which can produce economically recoverable amounts of elemental sulfur during regeneration. This objective will be accomplished by evaluating the sorbent performance using fixed-bed and TGA experiments supported by sorbent characterization at various reaction extents. In the seventh quarter, the screening of the promoted sorbents in the packed bed reactor was continued. The results of this work were presented at the 1992 University Coal Research Contractors, Review Conference at Pittsburgh, PA.

Akyurtlu, A.; Akyurtlu, J.F.

1992-01-01

440

Hot gas desulfurization with sorbents containing oxides of zinc, iron, vanadium and copper  

SciTech Connect

The main objective of this research is to evaluate the desulfurization performance of novel sorbents consisting of different combinations of zinc, iron, vanadium and copper oxides; and to develop a sorbent which can reduce H{sub 2}S levels to less than 1 ppmv, which can stabilize zinc, making operations above 650{degrees}C possible, and which can produce economically recoverable amounts of elemental sulfur during regeneration. This objective will be accomplished by evaluating the sorbent performance using fixed-bed and TGA experiments supported by sorbent characterization at various reaction extents. The work done in the fourth quarter can be summarized as follows: (1) Calibration of the gas chromatograph for low and high H{sub 2}S and SO{sub 2} is completed. (2) The determination of surface areas and densities of the promoted sorbents is completed. (3) Preliminary screening of the promoted sorbents in the packed bed reactor has started.

Akyurtlu, A.

1991-10-01

441

Highly conductive indium zinc oxide prepared by reactive magnetron cosputtering technique using indium and zinc metallic targets  

SciTech Connect

Zn-doped In{sub 2}O{sub 3} film is frequently deposited from an oxide target; but the use of metallic target is increasingly expected as preparing the film with comparable properties. This work aimed to prepare a highly conductive and transparent Zn-doped In{sub 2}O{sub 3} thin film on Corning Eagle{sup 2000} glass substrate by magnetron cosputtering method using indium and zinc targets. Structural characterization was performed using x-ray diffraction and x-ray photoelectron spectroscopy. The film had an amorphous structure when the film was prepared on an unheated substrate, but had an In{sub 2}O{sub 3} polycrystalline structure when the film was deposited on 150 and 300 deg. C substrates. The electrical properties of the film were greatly affected by annealing; the Zn-doped In{sub 2}O{sub 3} film had a low resistivity of 6.1x10{sup -4} {Omega} cm and an average transmittance of 81.7% when the film was deposited without substrate heating and followed a 600 deg. C annealing.

Tsai, T. K.; Chen, H. C.; Lee, J. H.; Huang, Y. Y.; Fang, J. S. [Department of Materials Science and Engineering, National Formosa University, Huwei, Yunlin 632, Taiwan (China); LinCo Technology, Taichung 407, Taiwan (China); Department of Materials Science and Engineering, National Formosa University, Huwei, Yunlin 632, Taiwan (China)

2010-05-15

442

Nitric Oxide and Zinc-Mediated Protein Assemblies Involved in Mu Opioid Receptor Signaling.  

PubMed

Opioids are among the most effective analgesics in controlling the perception of intense pain, although their continuous use decreases their potency due to the development of tolerance. The glutamate N-methyl-D-aspartate (NMDA) receptor system is currently considered to be the most relevant functional antagonist of morphine analgesia. In the postsynapse of different brain regions the C terminus of the mu-opioid receptor (MOR) associates with NR1 subunits of NMDARs, as well as with a series of signaling proteins, such as neural nitric oxide synthase (nNOS)/nitric oxide (NO), protein kinase C (PKC), calcium and calmodulin-dependent kinase II (CaMKII) and the mitogen-activated protein kinases (MAPKs). NO is implicated in redox signaling and PKC falls under the regulation of zinc metabolism, suggesting that these signaling elements might participate in the regulation of MOR activity by the NMDAR. In this review, we discuss the influence of redox signaling in the mechanisms whose plasticity triggers opioid tolerance. Thus, the MOR C terminus assembles a series of signaling proteins around the homodimeric histidine triad nucleotide-binding protein 1 (HINT1). The NMDAR NR1 subunit and the regulator of G protein signaling RGSZ2 bind HINT1 in a zinc-independent manner, with RGSZ2 associating with nNOS and regulating MOR-induced production of NO. This NO acts on the RGSZ2 zinc finger, providing the zinc ions that are required for PKC/Raf-1 cysteine-rich domains to simultaneously bind to the histidines present in the HINT1 homodimer. The MOR-induced activation of phospholipase ? (PLC?) regulates PKC, which increases the reactive oxygen species (ROS) by acting on NOX/NADPH, consolidating the long-term PKC activation required to regulate the Raf-1/MAPK cascade and enhancing NMDAR function. Thus, RGSZ2 serves as a Redox Zinc Switch that converts NO signals into Zinc signals, thereby modulating Redox Sensor Proteins like PKC? and Raf-1. Accordingly, redox-dependent and independent processes weave together to situate the MOR under the negative control of the NMDAR. PMID:23666425

Rodríguez-Muñoz, María; Garzón, Javier

2013-05-11

443

Effect of Annealing Temperature on the Surface Morphology and Electrical Properties of Aluminum Doped Zinc Oxide Thin Films Prepared by Sol-Gel Spin-Coating Method  

NASA Astrophysics Data System (ADS)

Aluminum doped zinc oxide thin films were prepared through sol gel and spin coating technique from zinc acetate dihydrate and aluminum nitrate nanohydrate in alcoholic solution. The electrical properties and surface morphology study are investigated for the thin films annealed at 350~500 °C. Zinc oxide thin films deposited on glass and silicon substrates were characterized using electron microscopy (SEM) and current-voltage (I-V) measurement scanning for surface morphology and electrical properties study respectively. The SEM investigation shows that zinc oxide thin films are denser at higher annealing temperature. The result indicates electrical properties of aluminum doped zinc oxide thin films are improved with annealing temperatures. The resistivity of aluminum doped zinc oxide thin films are decreased with annealing temperature up to 500 °C.

Mamat, M. H.; Amizam, S.; Rafaie, H. A.; Hashim, H.; Ahmed, A. Zain; Abdullah, S.; Rusop, M.

2008-05-01

444

Effect of annealing temperature on the surface morphology and electrical properties of aluminum doped zinc oxide thin films prepared by sol-gel spin-coating method  

SciTech Connect

Aluminum doped zinc oxide thin films were prepared through sol gel and spin coating technique from zinc acetate dihydrate and aluminum nitrate nanohydrate in alcoholic solution. The electrical properties and surface morphology study are investigated for the thin films annealed at 350{approx}500 deg. C. Zinc oxide thin films deposited on glass and silicon substrates were characterized using electron microscopy (SEM) and current-voltage (I-V) measurement scanning for surface morphology and electrical properties study respectively. The SEM investigation shows that zinc oxide thin films are denser at higher annealing temperature. The result indicates electrical properties of aluminum doped zinc oxide thin films are improved with annealing temperatures. The resistivity of aluminum doped zinc oxide thin films are decreased with annealing temperature up to 500 deg. C.

Mamat, M. H.; Hashim, H.; Rusop, M. [Faculty of Electrical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

2008-05-20

445

Property control of expanding thermal plasma deposited textured zinc oxide with focus on thin film solar cell applications  

Microsoft Academic Search

Property control of expanding thermal plasma deposited textured zinc oxide is demonstrated considering intrinsic, i.e. bulk, and extrinsic transparent conducting oxide quality relevant for application in thin film amorphous silicon pin solar cells. Particularly the interdependence of electrical conductivity, film composition and film morphology, i.e. structure, feature shape and roughness of the surface, is addressed. Control of film composition is

R. Groenen; J. Loffler; J. L. Linden; R. E. I. Schropp

2005-01-01

446

Effect of the Electrolyte Concentration on the Reversibility of a Nickel Oxide Electrode in a Nickel-Zinc Battery  

Microsoft Academic Search

The degree of charging of a nickel oxide electrode composed of spherical nickel hydroxide in a nickel-zinc battery was studied\\u000a in anodic oxidation of the electrode in KOH solutions of different concentrations, containing hydroxozincate ions.

Z. P. Arkhangel'skaya; A. V. Krasnobryzhii; M. M. Loginova; T. B. Kas'yan; E. V. Apollonova

2005-01-01

447

Functional zinc oxide nanostructures for electronic and energy applications  

NASA Astrophysics Data System (ADS)

ZnO has proven to be a multifunctional material with important nanotechnological applications. ZnO nanostructures can be grown in various forms such as nanowires, nanorods, nanobelts, nanocombs etc. In this work, ZnO nanostructures are grown in a double quartz tube configuration thermal Chemical Vapor Deposition (CVD) system. We focus on functionalized ZnO Nanostructures by controlling their structures and tuning their properties for various applications. The following topics have been investigated: (1) We have fabricated various ZnO nanostructures using a thermal CVD technique. The growth parameters were optimized and studied for different nanostructures. (2) We have studied the application of ZnO nanowires (ZnONWs) for field effect transistors (FETs). Unintentional n-type conductivity was observed in our FETs based on as-grown ZnO NWs. We have then shown for the first time that controlled incorporation of hydrogen into ZnO NWs can introduce p-type characters to the nanowires. We further found that the n-type behaviors remained, leading to the ambipolar behaviors of hydrogen incorporated ZnO NWs. Importantly, the detected p- and n- type behaviors are stable for longer than two years when devices were kept in ambient conditions. All these can be explained by an ab initio model of Zn vacancy-Hydrogen complexes, which can serve as the donor, acceptors, or green photoluminescence quencher, depend on the number of hydrogen atoms involved. (3) Next ZnONWs were tested for electron field emission. We focus on reducing the threshold field (Eth) of field emission from non-aligned ZnO NWs. As encouraged by our results on enhancing the conductivity of ZnO NWs by hydrogen annealing described in Chapter 3, we have studied the effect of hydrogen annealing for improving field emission behavior of our ZnO NWs. We found that optimally annealed ZnO NWs offered much lower threshold electric field and improved emission stability. We also studied field emission from ZnO NWs at moderate vacuum levels. We found that there exists a minimum Eth as we scale the threshold field with pressure. This behavior is explained by referring to Paschen's law.(4) We have studied the application of ZnO nanostructures for solar energy harvesting. First, as-grown and (CdSe) ZnS QDs decorated ZnO NBs and ZnONWs were tested for photocurrent generation. All these nanostructures offered fast response time to solar radiation. The decoration of QDs decreases the stable current level produced by ZnONWs but increases that generated by NBs. It is possible that NBs offer more stable surfaces for the attachment of QDs. In addition, our results suggests that performance degradation of solar cells made by growing ZnO NWs on ITO is due to the increase in resistance of ITO after the high temperature growth process. Hydrogen annealing also improve the efficiency of the solar cells by decreasing the resistance of ITO. Due to the issues on ITO, we use Ni foil as the growth substrates. Performance of solar cells made by growing ZnO NWs on Ni foils degraded after Hydrogen annealing at both low (300°C) and high (600°C) temperatures since annealing passivates native defects in ZnONWs and thus reduce the absorption of visible spectra from our solar simulator. Decoration of QDs improves the efficiency of such solar cells by increasing absorption of light in the visible region. Using a better electrolyte than phosphate buffer solution (PBS) such as KI also improves the solar cell efficiency. (5) Finally, we have attempted p-type doping of ZnO NWs using various growth precursors including phosphorus pentoxide, sodium fluoride, and zinc fluoride. We have also attempted to create p-type carriers via introducing interstitial fluorine by annealing ZnO nanostructures in diluted fluorine gas. In brief, we are unable to reproduce the growth of reported p-type ZnO nanostructures. However; we have identified the window of temperature and duration of post-growth annealing of ZnO NWs in dilute fluorine gas which leads to suppression of native defects. This is the first experimental effort on pos

Prasad, Abhishek

448

Effect of zinc and iron ions on the electrochemistry of nickel oxide electrode: Slow cyclic voltammetry. Technical report  

SciTech Connect

Porous sintered nickel oxide electrodes were prepared by cathodic electroprecipitation from metal nitrate solutions and characterized by slow (0.1 mV/s) voltammetry in 6 mol/l KOH. Presence of iron or zinc ions resulted in decrease of electrode charging ability and similar changes in voltammograms were observed for both ions. Removal of iron or zinc ions and introduction of lithium ions partially restored the electrode and corresponding voltammogram to original conditions. Presence of cobalt in the electrode material diminished substantially the influence of zinc ions on the electrode properties.... Storage batteries, Power sources, Membrane transport, Ion transport, Nafion.

Krejci, I.; Vanysek, P.

1993-04-07

449

Nitric oxide inhibits the formation of zinc protoporphyrin IX and protoporphyrin IX.  

PubMed

The aim of this study was to elucidate the mechanism by which curing agents, especially nitrite, inhibit the formation of zinc protoporphyrin IX (ZPP) in dry-cured hams such as Parma ham. The oxidation-reduction potential of model solutions was increased by the addition of nitrite, but it was not clear whether the formation of ZPP is inhibited by the oxidizing property of nitrite. The effect of nitric oxide (NO) produced from nitrite on the formation of ZPP was examined. The amount of ZPP formed was decreased by the addition of NO donors. The amount of protoporphyrin IX (PPIX), which is the precursor of ZPP, was also decreased by the addition of NO donors. It is concluded that NO produced from nitrite inhibited the formation of PPIX and ZPP was therefore not formed in cured meat products with the addition of nitrite or nitrate. PMID:20374763

Wakamatsu, Jun-ichi; Hayashi, Nobutaka; Nishimura, Takanori; Hattori, Akihito

2009-08-22

450

Study of structural and electrical properties of zinc oxide and Al-doped zinc oxide thin films deposited by DC sputtering  

NASA Astrophysics Data System (ADS)

Transparent conducting aluminum-doped and undoped ZnO thin films have been deposited by direct current (DC) sputtering technique from ZnO target onto glass substrate at room temperature and 400 °C. X-ray diffraction analysis shows that all films have a preferential growth along the c-axis of the hexagonal structure. The average grain size increases with the increasing deposition temperature and the doping of thin films. Analysis with AFM shows an improvement of the surface with the doping of thin films and deposition temperature. The root main square (RMS) surface roughness increases with deposition temperature. Al-doped ZnO (AZO) thin films have a lower electrical resistivity than that of ZnO thin films. 1/f noise measurement shows that ZnO thin film is more homogeneous than that of AZO.

Barhoumi, Amira; Yang, Liu; Sakly, Nawfel; Boughzala, Habib; Leroy, Gérard; Gest, Joël; Carru, Jean-Claude; Guermazi, Samir

2013-05-01

451

Tapered aluminum-doped vertical zinc oxide nanorod arrays as light coupling layer for solar energy applications  

Microsoft Academic Search

Tapered aluminum-doped vertical zinc oxide nanorod arrays have been prepared by using simple electrodeposition at 75°C from an aqueous solution of zinc nitrate and aluminum nitrate. Two substrates were used, i.e., copper indium gallium (di)selenide solar cells and a solar thermal absorber. The resulting nanorod arrays were of high optical quality, indicting their applicability as a light coupling layer via

Jie Chen; Hong Ye; Lorenz Aé; Yang Tang; David Kieven; Thorsten Rissom; Julia Neuendorf; Martha Ch. Lux-Steiner

2011-01-01

452

Coaxial nanocables of p-type zinc telluride nanowires sheathed with silicon oxide: synthesis, characterization and properties  

Microsoft Academic Search

Coaxial nanocables with a single-crystalline zinc telluride (ZnTe) nanowire core and an amorphous silicon oxide (SiOx) shell have been synthesized via a simple one-step chemical vapor deposition (CVD) method on gold-decorated silicon substrates. The single-crystal ZnTe nanowire core is in zinc-blende structure along the [111] direction, while the uniform SiOx shell fully covers the core with no observable pin-hole or

Y. L. Cao; Y. B. Tang; Y. Liu; Z. T. Liu; L. B. Luo; Z. B. He; J. S. Jie; Roy Vellaisamy; W. J. Zhang; C. S. Lee; S. T. Lee

2009-01-01

453

Greener syntheses of metallic nanoparticles and zinc oxide nanopowders  

NASA Astrophysics Data System (ADS)

In recent years, nanotechnology and nanomaterials synthesis have attracted a great deal of attention in the scientific community. Nanomaterials display size and morphology-related optical properties that differ from their bulk counterparts and therefore can be used for many applications in different fields such as biomedicine, electronics, antibacterial agents, and energy. Attempts to fabricate different morphologies of metallic and metal oxide nanoparticles (NPs) have successfully yielded attractive nanostructures such as particles, rods, helices, combs, tetra-pods, and flowers, all displaying properties mainly related to their enhanced surface area and/or aspect ratios. Most of the above mentioned nanomaterials productions have employed harsh synthetic routes such as high temperatures, low pressures, and the use of costly equipments. Here we show how a greener approach to nanomaterials synthesis is feasible with both minimization of aqueous precursors, energy and employment of a multi-block heater for temperature control. We present in this thesis several methods for the preparation of NPs of several materials that focus on minimizing the environmental impact of the synthesis itself. First, we describe the use of the toroidal form of plasmid DNA as a rigid narrowly dispersed bio-polymeric nanocavity, which mold the formation of disc-shaped nanoparticles of several types of metals. This approach exploits several properties of plasmid DNA: (a) DNA affinity for metal cations, (b) toroidal plasmid DNA structures which are favored by metal ionic binding, and (c) the ability to vary plasmid size. Herein, we present a complementary synthetic method based on a kinetic approach wherein the plasmid DNA acts as a template to initiate and control the formation of Au and other metallic NPs by incubation at elevated temperatures. Also reported herein is a simple, scalable hydrothermal method to make ZnO NPs that exploits temperature to precisely control the range of pH values of an organic amine buffer. The presence or absence of ethylenediaminetetraacetic acid in the tris(hydroxymethyl)aminomethane buffer further modulates the morphology of the ZnO nanomaterials since both compounds can serve as nucleating sites, and as stabilizing agents that prevents agglomeration.

Samson, Jacopo

454

Improved separators for silver oxide-zinc and silver oxide-cadmium cells for spacecraft applications. Final report, June 28 1963September 27, 1964. [30 to 45% KOH  

Microsoft Academic Search

The objective of the contract was to develop new and improved membranes for separators in sealed silver oxide-zinc and silver oxide-cadmium cells for spacecraft application. These cells contain highly concentrated (30 to 45%) potassium hydroxide. Conventionally, the separator material most generally used has been regenerated cellulose, cellophane. Several membranes were found superior to cellophane in overall performance. Films of six

H. L. Pfluger; H. E. Hoyt

1964-01-01

455

Thermodynamic and catalytic properties of solid solutions of copper and zinc oxides  

SciTech Connect

The central problem in the estimation of the thermodynamic data characterizing of solid phase is associated with the consideration of the parameters of fine crystal structure, chemical and phase composition. The analysis of thermodynamic and catalytic properties of the specimens based on copper and zinc oxides was performed in relation to the CuO/ZnO ratio with the aim to determine the solid solution stability, to estimate the energy of rearranging the nearest neighbor structure and the energy conditioned by the microcrystallinity and the defectiveness of the crystal state.

Smirnov, N.N.; Shirokov, Yu.G.; Artamonov, A.V.; Il`in, A.P.

1995-10-20

456

Chemical Etching of Zinc Oxide for Thin-Film Silicon Solar Cells  

PubMed Central

Abstract Chemical etching is widely applied to texture the surface of sputter-deposited zinc oxide for light scattering in thin-film silicon solar cells. Based on experimental findings from the literature and our own results we propose a model that explains the etching behavior of ZnO depending on the structural material properties and etching agent. All grain boundaries are prone to be etched to a certain threshold, that is defined by the deposition conditions and etching solution. Additionally, several approaches to modify the etching behavior through special preparation and etching steps are provided.

Hupkes, Jurgen; Owen, Jorj I; Pust, Sascha E; Bunte, Eerke

2012-01-01

457

The conductivity and magnetic properties of zinc oxide thin films doped with cobalt  

SciTech Connect

The magnetic properties, temperature dependences of the resistivity, Hall constant, and magnetoresistance of epitaxial zinc oxide films doped with cobalt are studied. The ferromagnetism of the films is observed at room temperature. The conduction and magnetoresistance of the films are attributed to transport of electrons in the conduction band at high temperatures and to hopping transport at low temperatures. With increasing concentration of cobalt dopants, the resistivity of the films increases and the concentration of electrons decreases. This is due to the increase in the ionization energy of donor states because of the increase in the energy of exchange interaction between electrons at donor states and electrons of the d shell of cobaltions.

Kytin, V. G., E-mail: kytin@mig.phys.msu.ru; Kulbachinskii, V. A.; Glebov, D. S.; Burova, L. I. [Moscow State University, Faculty of Physics (Russian Federation); Kaul, A. R.; Reukova, O. V. [Moscow State University, Faculty of Chemistry (Russian Federation)

2010-02-15

458

Mapping of two-photon luminescence amplification in zinc-oxide microstructures  

SciTech Connect

The mapping of two-photon excited luminescence in aggregations of free-standing zinc oxide microrods has been carried out at room temperature. Two-photon luminescence spectra in the excitonic region for individual microrods have been recorded. The luminescence intensity exhibits a power-law dependence on the optical pump power with the exponent n > 2. This fact, along with the existence of a threshold power above which the dependence in the exciton region deviates from a quadratic one, indicates the onset of light amplification in individual ZnO microrods and the conditions preceding laser oscillation.

Semin, S. V., E-mail: sv_semin@mail.ru; Sherstyuk, N. E.; Mishina, E. D. [Moscow State Technical University of Radio Engineering, Electronics and Automation (Russian Federation); Gherman, C.; Kulyuk, L. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Rasing, Th. [Radboud University Nijmegen, Institute for Molecules and Materials (Netherlands); Peng, L.-H. [National Taiwan University, Department of Electrical Engineering and Institute of Photonics and Optoelectronics (China)

2012-03-15

459

Effects of Different Precursor's Concentration on the Properties of Zinc Oxide Thin Films  

SciTech Connect

Zinc oxide (ZnO) thin films were successfully grown on silicon substrate with different molarities, by a sol-gel method. In the process, the molarities were varied from 0.2-1.0 M and it was found that increasing in molarities had affected the structure of ZnO thin films. The properties of the thin films were characterized and studied by ultraviolet-visible spectroscopy (UV-Vis) and photoluminescence spectrometer (PL). It was found that the molarities affect the optical properties of the resultant ZnO thin films.

Malek, M. F.; Zakaria, N.; Sahdan, M. Z.; Mamat, M. H. [Faculty of Electrical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Khusaimi, Z. [NANO-SciTech Centre, Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Rusop, M. [Faculty of Electrical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre, Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

2010-07-07

460

Structural and optical properties of zinc oxide film using RF-sputtering technique  

SciTech Connect

This paper reports the fabrication of zinc oxide (ZnO) film using RF-sputtering technique. Determination of the structural properties using High Resolution X-ray Diffraction (HRXRD) confirmed that ZnO film deposited on silicon (Si) substrate has a high quality. This result is in line with the Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) which were used to image the morphology of the film, in which a rough surface was demonstrated. Photoluminescence (PL) emission is included to study the optical properties of ZnO film that shows two PL peak in the UV region at 371 nm and in visible region at 530 nm respectively.

Hashim, A. J.; Jaafar, M. S.; Ghazai, Alaa J. [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 Pinang (Malaysia); Physics Department, Science College, Thi-Qar University (Iraq)

2012-11-27

461

Origin of ferromagnetism enhancement in bi-layer chromium-doped indium zinc oxides  

SciTech Connect

This work demonstrates that by controlling the rapid thermal annealing temperature, amorphous chromium-doped indium zinc oxide films develop an amorphous-crystalline bi-layer structure and show magnetization up to {approx}30 emu/cm{sup 3}. The crystalline layer arises from significant out-diffusion of Zn from surfaces, leading to a large difference in the Zn:In ratio in amorphous and crystalline layers. Doped Cr ions in amorphous and crystalline layers form different valence configurations, creating a charge reservoir which transfers electrons through amorphous-crystalline interfaces and in turn enhances ferromagnetism.

Hsu, C. Y. [Physics Department, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China)

2012-08-06

462

Zinc oxide nanostructures with metal particles based on surface plasmons for optoelectronic device applications  

NASA Astrophysics Data System (ADS)

We fabricate various ZnO (zinc oxide) nanostructures, such as nanorods, nanotips and nanoflowers, as well as ZnO subwavelength grating structures for applications in optoelectronic devices such as solar cells, light emitting diodes, and biosensors. The optical properties are theoretically analyzed using the rigorous coupled-wave analysis method. The fabricated ZnO nanostructures are of wurzite crystal structure. The reflection and absorption characteristics depend strongly on the shape and geometry of Zn nanostructures. The ZnO nanostructures with Au (or Ag) particles, based on surface plasmons, are also investigated.

Yu, Jae Su; Ko, Yeong Hwan; Lee, Hee Kwan; Leem, Jung Woo

2011-02-01

463

Synthesis and magnetic properties of one-dimensional zinc nickel oxide solid solution.  

PubMed

A novel facile method has been demonstrated for large-scale synthesis of zinc-oxide-based one-dimensional solid solution with a series percentage of nickel dopant. The obtained Zn1-xNixO nanorods were characterized by X-ray diffraction, transmission electron microscopy, selected area electron diffraction, and energy dispersed X-ray spectroscopy. The result shows that the obtained Zn1-xNixO nanorods are single crystalline with the Ni2+ dopants occupying tetrahedral Zn2+ cation sites of wurtzite ZnO. Moreover, the Zn1-xNixO nanorods exhibit robust high-Curie-temperature (TC) ferromagnetism at 300 K. PMID:17447736

Zhang, Xiao Li; Qiao, Ru; Qiu, Ri; Li, Yan; Kang, Young Soo

2007-04-21

464

395-nm and 790-nm femtosecond laser ablation of aluminum-doped zinc oxide  

NASA Astrophysics Data System (ADS)

We used 395-nm and 790-nm femtosecond laser pulses to deposit aluminum-doped zinc oxide films by pulsed laser deposition. Electrical resistivity of the films was lowered (5.6 x 104(Omega) cm) at 200 degree(s)C for the 395-nm laser pulses, while maintaining the optical transparency. In addition, the deposition rate increased six times. Optical emission was measured to compare the plumes generated by 395-nm and 790-nm laser pulses. We found that the emission from ions was suppressed relative to neutral atoms. Also the kinetic energy of ejected species was nearly doubled for the 395-nm laser pulses.

Okoshi, Masayuki; Higashikawa, Kouji; Hanabusa, Mitsugu

2000-11-01

465

Effect of Ultraviolet Light on Hybrid Zinc Oxide Polymer Bulk Heterojunction Solar Cells  

Microsoft Academic Search

Compared to conjugated polymer poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) sol