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1

Zinc/Zinc Oxide Preliminary Source Assessment.  

National Technical Information Service (NTIS)

A preliminary source assessment of industries with zinc and/or zinc oxide emissions is presented. Brief descriptions of these industries and associated air pollution control equipment are presented. Zinc/zinc oxide emission data were primarily obtained fr...

1987-01-01

2

Performance of aluminum-doped zinc oxide thin films under bending fatigue conditions  

Microsoft Academic Search

Aluminum-doped zinc oxide (AZO) film is a promising candidate for low cost transparent conductive oxide (TCO) applications. It is a viable alternative to indium tin oxide (ITO), the dominant material used in TCO. Although AZO has good electrical and optical properties, its mechanical properties must be thoroughly considered in the design and manufacturing of flexible devices. During the manufacture and

Chien-Yi Peng; Hema Sudarsanam; Mohammad M. Hamasha; Susan Lu; Tara P. Dhakal; Charles R. Westgate

2012-01-01

3

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

4

Co-sputtered Aluminum Doped Zinc Oxide Thin Film as Transparent Anode for Organic Light-emitting Diodes  

Microsoft Academic Search

Aluminum doped zinc oxide (AZO) is a promising transparent conducting oxide (TCO), which have the advantages of low material cost, low toxicity and chemical stability in reducing ambient over ITO. In this report, AZO was grown by sputtering Al target and ZnO target simultaneously, and the Al dopant concentration can be easily tuned by adjusting sputtering power set. The acquired

Haiying Chen; Chengfeng Qiu; Huajun Peng; Zhilang Xie; H. S. Kwok

5

Holographic grating formation in laser-deposited aluminium-doped zinc oxide and indium tin oxide films  

Microsoft Academic Search

Holographic grating formation is demonstrated in films of the transparent and semiconducting materials aluminium-doped zinc oxide (AZO) and indium tin oxide (ITO) produced by pulsed laser deposition. The holographic gratings are induced by UV laser light at 356 nm. The physics and characteristics of grating formation in laser-deposited AZO and ITO films are compared with those of sputter-deposited indium oxide

Birgitte Thestrup; Carsten Dam-Hansen; Jørgen Schou; Per Michael Johansen

2000-01-01

6

Study of high-density AZO ceramic target  

Microsoft Academic Search

Aluminum-doped zinc oxide (AZO) powders and the powders doped with niobium and gallium were prepared by chemical co-precipitation method. The AZO targets with high density were made by molding and atmospheric pressure sintering. The morphologies, microstructure, and electrical property of the AZO targets were characterized by XRD, SEM, and Hall test. The measured results have showed that the resistivity of

Jing Zhang; Weijia Zhang; Erjing Zhao; Havugimana Jean Jacques

7

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

8

Phenolic Azo Dye Oxidation by Laccase from Pyricularia oryzae  

PubMed Central

Laccase oxidation of phenolic azo dyes was examined with a commercially available laccase from Pyricularia oryzae as the model. Methyl-, methoxy-, chloro-, and nitro-substituted derivatives of 4-(4(prm1)-sulfophenylazo)-phenol were examined as substrates for this laccase. Only the substituents on the phenolic ring were changed. Among the dyes examined, only 2-methyl-, 2-methoxy-, 2,3-dimethyl-, 2,6-dimethyl-, 2,3-dimethoxy-, and 2,6-dimethoxy-substituted 4-(4(prm1)-sulfophenylazo)-phenol served as substrates. Preliminary kinetic studies suggest that 2,6-dimethoxy-substituted 4-(4(prm1)-sulfophenylazo)-phenol is the best substrate. Laccase oxidized the 2,6-dimethyl derivative of 4-(4(prm1)-sulfophenylazo)-phenol to 4-sulfophenylhydroperoxide (SPH) and 2,6-dimethyl-1,4-benzoquinone. The 2-methyl- and 2-methoxy-substituted dyes were oxidized to SPH and either 2-methyl- or 2-methoxy-benzoquinone. Six products were formed from laccase oxidation of the 2,6-dimethoxy-substituted dye. Three of them were identified as SPH, 4-hydroxybenzenesulfonic acid, and 2,6-dimethoxybenzoquinone. A mechanism for the formation of benzoquinone and SPH from laccase oxidation of phenolic azo dyes is proposed. This study suggests that laccase oxidation can result in the detoxification of azo dyes.

Chivukula, M.; Renganathan, V.

1995-01-01

9

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

10

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

11

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

12

The physical properties of Al-doped zinc oxide films prepared by RF magnetron sputtering  

Microsoft Academic Search

Al-doped zinc oxide (AZO) films are prepared by RF magnetron sputtering on glass and Si substrates with specifically designed ZnO targets containing different amounts of Al2O3 powder as a doping source. The physical properties of the AZO films are investigated in terms of the preparation conditions, such as Al2O3 content in the target, RF power (PRF), substrate temperature (Ts) and

Ki Cheol Park; Dae Young Ma; Kun Ho Kim

1997-01-01

13

Structural property of polycrystalline silicon films on aluminum-doped zinc oxide-coated glass  

Microsoft Academic Search

The structural properties of crystalline silicon (Si) films on bare and aluminum-doped zinc oxide (AZO)-coated glass substrates were comparatively investigated by X-ray diffractometer, Raman spectroscopy, and transmission electron microscope. It was observed that for the amorphous Si (a-Si) films on bare and AZO-coated glass substrates subjected to five-step rapid thermal annealing (RTA) at 750°C\\/60s, they were both polycrystalline in nature

Weiyan Wang; Jinhua Huang; Xianpeng Zhang; Ye Yang; Ruiqin Tan; Weijie Song

2011-01-01

14

Water electrolysis-induced optical degradation of aluminum-doped zinc oxide films  

Microsoft Academic Search

A type of optical degradation of aluminium-doped zinc oxide (AZO) films due to water electrolysis-induced reduction reaction was reported. An experiment was designed in which AZO films were immersed in a 0.01M NaOH aqueous solution as cathode to electrolyze water. Significant decreases in the optical transmission of the treated samples were observed. Studies by X-ray diffraction and scanning electron microscope

Linggang Fang; Guojia Fang; Wanping Chen; Chun Li; Su Sheng; Shuang Ma; Xingzhong Zhao

2006-01-01

15

Solar photoassisted advanced oxidation process of azo dyes.  

PubMed

Advanced oxidation processes assisted with natural solar radiation in CPC type reactors (parabolic collector compound), was applied for the degradation of three azo dyes: acid orange (AO7), acid red 151 (AR151) and acid blue 113 (AB113). Fenton, Fenton like and ferrioxalate-type complexes showed to be effective for degrade the azo linkage and moieties in different extensions. Initially, the best dose of reagents (Fe(3 + )-H(2)O(2)) was determined through a factorial experimental design, next, using response surface methodologies, the reagent consumption was reduced up to 40%, maintaining in all cases high decolourisation percentages (>98%) after 60 min. of phototreatment. In this work, it was also studied the effect of concentration changes of the influent between 100-300 mg/L and the operation of the photocatalytic process near neutral conditions (pH 6.0-6.5) by using ferrioxalate type complex (FeOx). PMID:19273895

Prato-Garcia, D; Buitrón, G

2009-01-01

16

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

17

Flexible aluminum-doped zinc-oxide thin-film transistor fabricated on plastic substrates  

NASA Astrophysics Data System (ADS)

We have studied processing and characteristics of flexible Aluminum-doped Zinc Oxide thin-film transistors (AZO TFTs) fabricated on plastic substrates using radio frequency (rf) magnetron sputtering. To improve the performance of flexible AZO TFT, we studied effects of device structures on characteristics of the aluminum-doped zinc oxide thin film transistors. The electrical properties of top-gate type and bottom-gate type AZO TFTs were investigated, respectively. The top-gate type AZO TFTs shows a threshold voltage of 1.4 V, a Ion/Ioff current ratio of 1.0×107, a field effect mobility of 28.2 cm2/ V•s, a subthreshold swing of 0.19 V/decade. And the bottom-gate type AZO TFTs shows a threshold voltage of 1.7 V, a Ion/Ioff ratio of 1.0×107, a field effect mobility of 209 cm2/ V•s, a subthreshold swing of 0.16 V/decade, and the off current of less than 10-11A at room temperature. Both TFTs show low threshold voltage, high Ion/Ioff ratio and high field effect mobility. By comparison, the bottom-gate type AZO TFTs shows better characteristics. The flexible AZO-TFT is a very promising low-cost optoelectronic device for the next generation of invisible and flexible electronics due to flexible, transparency, high mobility, and low-temperature processing.

Han, Dedong; Chen, Zhuofa; Zhao, Nannan; Wang, Wei; Huang, Fuqing; Zhang, Shengdong; Zhang, Xing; Wang, Yi

2014-03-01

18

21 CFR 73.2991 - Zinc oxide.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Zinc oxide. 73.2991 Section 73.2991...CERTIFICATION Cosmetics § 73.2991 Zinc oxide. (a) Identity and specifications. The color additive zinc oxide shall conform in identity and...

2009-04-01

19

21 CFR 73.2991 - Zinc oxide.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Zinc oxide. 73.2991 Section 73.2991...CERTIFICATION Cosmetics § 73.2991 Zinc oxide. (a) Identity and specifications. The color additive zinc oxide shall conform in identity and...

2010-04-01

20

Degradation of azo dyes by oxidative processes – Laccase and ultrasound treatment  

Microsoft Academic Search

Azo dyes are of synthetic origin and their environmental fate is not well understood. They are resistant to direct aerobic bacterial degradation and form potentially carcinogenic aromatic amines by reduction of the azo group. This study shows that applying the oxidative processes of enzymatic treatment with laccase and ultrasound treatment, both alone and in combination, leads to dye degradation. Laccase

Michael M. Tauber; Georg M. Gübitz; Astrid Rehorek

2008-01-01

21

Zinc oxide varistors and\\/or resistors  

Microsoft Academic Search

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

Arnold Jr. Wesley D; Walter D. Bond; Robert J. Lauf

1993-01-01

22

Interstitial zinc clusters in zinc oxide  

NASA Astrophysics Data System (ADS)

Doped zinc oxide (ZnO) exhibits anomalous Raman modes in the range of 270 to 870 cm-1. Commonly, the resonance at 275 cm-1 is attributed to the local vibration of Zn atoms in the vicinity of extrinsic dopants. We revisit this assignment by investigating the influence of isotopically purified zinc oxide thin films on the frequency of the vibrational mode around 275 cm-1. For this purpose, undoped and nitrogen-doped ZnO thin-films with Zn isotope compositions of natural Zn, 64Zn, 68Zn, and a 1:1 mixture of 64Zn and 68Zn were grown by pulsed laser deposition. The isotopic shift and the line shape of the Raman resonance around 275 cm-1 are analyzed in terms of three different microscopic models, which involve the vibration of (i) interstitial zinc atoms bound to extrinsic defects, (ii) interstitial diatomic Zn molecules, and (iii) interstitial zinc clusters. The energy diagram of interstitial Zn-Zn bonds in a ZnO matrix is derived from density functional theory calculations. The interstitial Zn-Zn bond is stabilized by transferring electrons from the antibonding orbital into the ZnO conduction band. This mechanism facilitates the formation of interstitial Zn clusters and fosters the common n-type doping asymmetry of ZnO.

Gluba, M. A.; Nickel, N. H.; Karpensky, N.

2013-12-01

23

Zinc oxide varistors and\\/or resistors  

Microsoft Academic Search

Varistors and\\/or resistors are described that include 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

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

1993-01-01

24

Transparent conducting aluminum-doped zinc oxide thin film prepared by sol–gel process followed by laser irradiation treatment  

Microsoft Academic Search

Aluminum-doped zinc oxide (AZO) films were fabricated at a low substrate temperature (300 °C) in air by KrF excimer laser irradiation of sol–gel spin-coated films. Structural, electrical and optical properties of the laser-irradiated films at different laser energies were studied and compared with those prepared by conventional high-temperature processing. The 200 nm laser-irradiated AZO film shows a resistivity of 44×10?3 ?-cm and about

W. M. Tsang; F. L. Wong; M. K. Fung; J. C. Chang; C. S. Lee; S. T. Lee

2008-01-01

25

ENZ waveguide of Al-doped zinc oxide for telecommunication applications  

NASA Astrophysics Data System (ADS)

We investigate the incorporation of an epsilon-near-zero (ENZ) material into a waveguide structure in order to suppress dispersion associated with the interaction of light with material in the core, guiding layer. ENZ metamaterials can provide a mechanism for air-core waveguides by introduction of a cladding medium exhibiting a refractive index less than unity. We study the application of aluminum zinc oxide (AZO), a transparent conducting oxide, as the candidate for ENZ waveguides. For this purpose, we design a metamaterial cladding layer with ENZ properties derived from nanoparticles of AZO, and investigate the resulting loss and dispersion of guided optical signals.

Alisafaee, Hossein; Fullager, Daniel B.; Fiddy, Michael A.

2014-02-01

26

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

27

Zinc oxide varistors and/or resistors  

SciTech Connect

Varistors and/or resistors are described that include 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, W.D. Jr.; Bond, W.D.; Lauf, R.J.

1993-07-27

28

Highly conductive and transparent reduced graphene oxide/aluminium doped zinc oxide nanocomposite for the next generation solar cell applications  

NASA Astrophysics Data System (ADS)

In this paper, aluminum-doped zinc oxide(AZO)/reduced graphene oxide nano-composite thin films are synthesized by a one-pot, solution-processed method. The nanocomposite film has been extensively characterized using scanning electron microscopy (SEM), X-ray-diffraction (XRD), energy dispersive spectroscopy (EDS), Hall effect measurement and UV-Vis spectroscopy. It is found that the controlled addition of reduced graphene oxide into AZO can lower the film's resistivity without causing significant degradation of optical transparency. In addition, nanocomposite films post-annealed at process temperature at 500 °C possesses the lowest resistivity and the highest optical transmittance and that further increases in the annealing temperature degrades the film's property due to nucleation of other phases of the AZO.

Bu, Ian Y. Y.

2013-12-01

29

Zinc oxide nanorods  

NASA Astrophysics Data System (ADS)

Non-lithographic, bottom-up techniques have been developed to advance the state of the art and contribute to the development of new material structures, fabrication methods, devices, and applications using the Zinc Oxide material system as a demonstration vehicle. The novel low temperature catalytic vapour-liquid-solid growth process developed is technologically simple, inexpensive, and a robust fabrication technique offering complete control over the physical dimensions of the nanorod such as its diameter and length, and over the positioning of the nanorods for site-selective growth. By controlling the distribution of the Au catalysts with the use of a self-organized anodized aluminum oxide nanopore membrane as a template, we have been able to synthesize highly ordered, hexagonally packed, array of ZnO nanorods spanning a large area. These nanorods are single crystal, hexagonally shaped, indicative of the wurtzite structure, and are vertically aligned to the substrate. By pre-patterning the template, arbitrary nanorod patterns can be formed. We have also demonstrated the assembly of the nanorods into functional devices using controlled methods that are less resource intensive, easily scalable, and adaptable to other material systems, without resorting to the manipulation of each individual nanostructures. Examples of these devices include the random network device that exploits the common attributes of the nanorods, and those formed using an external field to control the nanorod orientation. Two and three terminal device measurements show that the as-grown nanorods are n-type doped, and that by controlling the external optical excitation and its test environment, the photoconductivity can be altered dramatically. Self assemble techniques such as the spontaneous formation of nanodendrites into complex networks of interconnects were studied. Controlled formation of interconnects achieved by controlling the placement of the catalyst is demonstrated by growing the nanorods on existing ZnO nanorods and on carbon nanotubes creating heterojunctions. Arbitrary controlled heterojunction 3-D networks are envisioned providing increased device functionalities. The nanorods were also integrated with existing devices such as the atomic force microscope tips. Finally, we have developed a base technology for lateral current injection devices often seen as a paradigm shift for optoelectronic devices.

Chik, Hope Wuming

30

Multi-wavelength Raman scattering of nanostructured Al-doped zinc oxide  

NASA Astrophysics Data System (ADS)

In this work we present a detailed Raman scattering investigation of zinc oxide and aluminum-doped zinc oxide (AZO) films characterized by a variety of nanoscale structures and morphologies and synthesized by pulsed laser deposition under different oxygen pressure conditions. The comparison of Raman spectra for pure ZnO and AZO films with similar morphology at the nano/mesoscale allows to investigate the relation between Raman features (peak or band positions, width, relative intensity) and material properties such as local structural order, stoichiometry, and doping. Moreover Raman measurements with three different excitation lines (532, 457, and 325 nm) point out a strong correlation between vibrational and electronic properties. This observation confirms the relevance of a multi-wavelength Raman investigation to obtain a complete structural characterization of advanced doped oxide materials.

Russo, V.; Ghidelli, M.; Gondoni, P.; Casari, C. S.; Li Bassi, A.

2014-02-01

31

Study on the electrical and optical properties of ITO and AZO thin film by oxygen gas flow rate  

Microsoft Academic Search

Transparent conductive oxide (TCO) thin films such as tin doped indium oxide (ITO), zinc doped indium oxide (IZO) and Al doped\\u000a zinc oxide (AZO) have been widely used as transparent electrode for display. ITO and AZO thin films for display was prepared\\u000a by the facing targets sputtering (FTS) system. The FTS method is called a plasma-free sputter method because the

Sang-Mo Kim; You-Seung Rim; Min-Jong Keum; Kyung-Hwan Kim

2009-01-01

32

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

33

Different properties of aluminum doped zinc oxide nanostructured thin films prepared by radio frequency magnetron sputtering  

SciTech Connect

Aluminium doped zinc oxide (AZO) nanostructured thin films are prepared by radio frequency magnetron sputtering on glass substrate using specifically designed ZnO target containing different amount of Al{sub 2}O{sub 3} powder as the Al doping source. The optical properties of the aluminium doped zinc oxide films are investigated. The topography of the deposited films were investigated by Atomic Force Microscopy. Variation of the refractive index by annealing temperature are considered and it is seen that the refractive index increases by increasing the annealing temperature.

Bidmeshkipour, Samina, E-mail: samina204@gmail.com; Shahtahmasebi, Nasser [Ferdowsi University of Mashhad, Department of Physics (Iran, Islamic Republic of)

2013-06-15

34

Effects of starting material of aluminum doped zinc oxide underlayer on the electric properties of palladium doped silver film  

NASA Astrophysics Data System (ADS)

Crystallographic and electric properties of a palladium doped silver (Ag-Pd) layer formed on an aluminum doped zinc oxide (AZO) film in the multilayer system of Ag-Pd(10.5 nm)/AZO(42 nm)/glass were investigated. All of the films in this study were deposited by dc magnetron sputtering. Two kinds of sputtering targets, aluminum doped zinc metal (AZ) and AZO, were used for the deposition of AZO films. The AZ target was sputtered in an oxygen or carbon dioxide atmosphere whereas the AZO target was sputtered in an argon or argon/oxygen atmosphere. The Ag-Pd layers were deposited under the fixed sputtering condition. From x-ray diffraction patterns it was found that the most developed Ag(111) peak appeared in the case of the Ag-Pd film on the AZO layer deposited from the AZ metal target with oxygen. Atomic force microscope observation revealed that the smallest surface roughness was obtained in this case. Electrical resistivity of the Ag-Pd layer changed by up to 17% depending on deposition conditions and the target materials of the underlayer. The Ag-Pd film deposited on the AZO layer from the AZ target in an oxygen atmosphere also showed the lowest resistivity of 7.1×10-6 ? cm. The smallest refractive index of Ag-Pd film was shown by the same sample from an analysis using spectroscopic ellipsometry (SE). Deposition of a thin metal (Zn-Al) overlayer on Ag-Pd/AZO/glass increased the overall resistivity of the multilayer. This may imply the diffusion of zinc atoms into the Ag-Pd layer, however, the resistivity recovery was observed after some storage time, which suggests the effect of an electron scattering at the surface.

Oyama, T.; Maekawa, M.; Yanagisawa, T.

2003-07-01

35

Salicylic acid as a tridentate anchoring group for azo-bridged zinc porphyrin in dye-sensitized solar cells.  

PubMed

Two series dyes of azo-bridged zinc porphyrins have been devised, synthesized, and performed in dye-sensitized solar cells, in which salicylic acids and azo groups were introduced as a new anchoring group and ?-conjugated bridge via a simple synthetic procedure. The representation of the new dyes has been investigated by optical, photovoltaic, and electrochemical means. The photoelectric conversion efficiency of their DSSC devices has been improved compared with other DSSC devices sensitized by symmetrical porphyrin dyes. The results revealed that tridentate binding modes between salicylic acid and TiO2 nanoparticles could enhance the efficiency of electron injection. The binding modes between salicylic acid and TiO2 nanoparticles may play a crucial role in the photovoltaic performance of DSSCs. PMID:24229086

Gou, Faliang; Jiang, Xu; Li, Bo; Jing, Huanwang; Zhu, Zhenping

2013-12-11

36

Efficient indium-tin-oxide free inverted organic solar cells based on aluminum-doped zinc oxide cathode and low-temperature aqueous solution processed zinc oxide electron extraction layer  

NASA Astrophysics Data System (ADS)

Indium-tin-oxide (ITO) free inverted organic solar cells (IOSCs) based on aluminum-doped zinc oxide (AZO) cathode, low-temperature aqueous solution processed zinc oxide (ZnO) electron extraction layer, and poly(3-hexylthiophene-2, 5-diyl):[6, 6]-phenyl C61 butyric acid methyl ester blend were realized in this work. The resulted IOSC with ZnO annealed at 150 °C shows the superior power conversion efficiency (PCE) of 3.01%, if decreasing the ZnO annealing temperature to 100 °C, the obtained IOSC also shows a PCE of 2.76%, and no light soaking issue is observed. It is found that this ZnO film not only acts as an effective buffer layer but also slightly improves the optical transmittance of AZO substrates. Further, despite the relatively inferior air-stability, these un-encapsulated AZO/ZnO IOSCs show comparable PCEs to the referenced ITO/ZnO IOSCs, which demonstrates that the AZO cathode is a potential alternative to ITO in IOSCs. Meanwhile, this simple ZnO process is compatible with large area deposition and plastic substrates, and is promising to be widely used in IOSCs and other relative fields.

Chen, Dazheng; Zhang, Chunfu; Wang, Zhizhe; Zhang, Jincheng; Tang, Shi; Wei, Wei; Sun, Li; Hao, Yue

2014-06-01

37

Growth of Zinc Oxide Nanobelts  

NASA Astrophysics Data System (ADS)

Zinc Oxide is a unique material that has a variety of applications in optoelectronics due to its piezoelectric, optical, and semiconducting properties. The carbothermal reduction of zinc oxide is a common technique used in chemical vapor deposition of nanostructures via the vapor transport mechanism. In this research project, the supply of zinc atom was successfully decoupled from the delivery of the oxidant, molecular oxygen. We have grown various forms of ZnO nanostructures at varying temperatures in a three-zone furnace. The reactions took place at a constant pressure of 200 torr on silicon substrates, each coated with a thin film of gold catalyst. Two-dimensional nano-ribbons were observed to grow best at higher temperatures between 800-1000 C, with the thinnest belts (30 nm) at 800 C. At 1000 C, the belts appear to taper off, resulting in shorter structures. One-dimensional wire growth was predominantly observed at 600 C. We compare our results with previously published syntheses of ZnO nanobelts.

Nowalk, Jamie

2013-03-01

38

Zinc absorption from zinc oxide, zinc sulfate, zinc oxide + EDTA, or sodium-zinc EDTA does not differ when added as fortificants to maize tortillas.  

PubMed

The fortification of staple foods with zinc may play an important role in achieving adequate zinc intakes in countries at risk of zinc deficiency. However, little is known about the relative bioavailability of different zinc compounds that may be used in food fortification. The objective of this study was to measure and compare fractional zinc absorption from a test meal that included a maize tortilla fortified with zinc oxide, zinc sulfate, zinc oxide + EDTA, or sodium-zinc EDTA. A double isotopic tracer ratio method ((67)Zn as oral tracer and (70)Zn as intravenous tracer) was used to estimate zinc absorption in 42 Mexican women living in a periurban community of Puebla State, Mexico. The test meal consisted of maize tortillas, yellow beans, chili sauce, and milk with instant coffee; it contained 3.3 mg zinc and had a phytate:zinc molar ratio of 17. Fractional zinc absorption did not differ significantly between the test groups (ANOVA; P > 0.05). Percent absorptions were (mean +/- SD) zinc oxide, 10.8 +/- 0.9; zinc sulfate, 10.0 +/- 0.02; zinc oxide + EDTA, 12.7 +/- 1.5; and sodium-zinc EDTA, 11.1 +/- 0.7. We conclude that there was no difference in zinc absorption from ZnO and ZnSO(4) when added as fortificants to maize tortillas and consumed with beans and milk. The addition of EDTA with zinc oxide or the use of prechelated sodium-zinc EDTA as fortificants did not result in higher zinc absorption from the test meal. PMID:15867288

Hotz, Christine; DeHaene, Jessica; Woodhouse, Leslie R; Villalpando, Salvador; Rivera, Juan A; King, Janet C

2005-05-01

39

Development of Novel Al-Doped Zinc Oxide Films Fabricated on Etched Glass and Their Application to Solar Cells  

NASA Astrophysics Data System (ADS)

We have successfully developed novel aluminum-doped zinc oxide (AZO-X) films with a high haze ratio by the combined use of an etched glass substrate and wet-etched AZO-X films. The effects of the use of an etched glass substrate and wet-chemical etching on the properties of AZO-X films were investigated. The texture size and rms roughness of these films largely increased with glass surface roughening. Post-treatment using wet chemical etching slightly increased the texture size and rms roughness. The etched glass approach has been found to be a promising method for achieving an AZO-coated glass substrate with a high haze ratio. Using high-haze ratio AZO-X films as the front transparent conductive oxide (TCO) layers in solar cells, we improved the quantum efficiency (QE) of these solar cells particularly in the long-wavelength region. Thus, the AZO-X films deposited on etched glass have a high potential for use as front TCO layers in silicon-based thin-film solar cells.

Hongsingthong, Aswin; Aino, Akehiro; Sichanugrist, Porponth; Konagai, Makoto; Kuramochi, Hideto; Akiike, Ryo; Iigusa, Hitoshi; Utsumi, Kentaro; Shibutami, Tetsuo

2012-10-01

40

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.

41

Combined kinetic and spectroscopic study of oxidation of azo dyes in surfactant solutions by hypochlorite  

Microsoft Academic Search

Combined kinetic, spectroscopic and thermodynamic investigations have been carried out to examine the influence of cationic, anionic and nonionic surfactants upon the oxidation of an azo dye, II, by hypochlorite. Oxidation rates were unaffected by the presence of anionic or nonionic surfactant (SDS or C12E5) either in micellar or submicellar regions: indicating the absence of any specific dye–surfactant interactions. On

John Oakes; Peter Gratton; Toby Gordon-Smith

2000-01-01

42

Bidirectional reflectance of zinc oxide  

NASA Technical Reports Server (NTRS)

This investigation was undertaken to determine original and useful information about the bidirection reflectance of zinc oxide. The bidirectional reflectance will be studied for the spectra between .25-2.5 microns and the hemisphere above the specimen. The following factors will be considered: (1) surface conditions; (2) specimen preparation; (3) specimen substrate, (4) polarization; (5) depolarization; (6) wavelength; and (7) angles of incident and reflection. The bidirectional reflectance will be checked by experimentally determined angular hemispherical measurements or hemispherical measurements will be used to obtain absolute bidirectional reflectance.

Scott, R.

1973-01-01

43

Directed spatial organization of zinc oxide nanostructures  

DOEpatents

A method for controllably forming zinc oxide nanostructures on a surface via an organic template, which is formed using a stamp prepared from pre-defined relief structures, inking the stamp with a solution comprising self-assembled monolayer (SAM) molecules, contacting the stamp to the surface, such as Ag sputtered on Si, and immersing the surface with the patterned SAM molecules with a zinc-containing solution with pH control to form zinc oxide nanostructures on the bare Ag surface.

Hsu, Julia (Albuquerque, NM); Liu, Jun (Richland, WA)

2009-02-17

44

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

45

Photocatalytic activity of nanoparticle gold\\/iron oxide aerogels for azo dye degradation  

Microsoft Academic Search

Nanoparticle gold\\/iron oxide (maghemite) aerogels were used as photocatalysts to degrade Disperse Blue 79 azo dye in water under ultraviolet light illumination. They were characterized by diffuse reflection spectroscopy (DRS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy. Addition of gold species caused the light absorption to shift towards the red visible region, and thus the band

Chien-Tsung Wang

2007-01-01

46

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

47

[Clinical studies on zinc oxide ointment replacing boric acid and zinc oxide ointment (JP8)].  

PubMed

A boric acid and zinc oxide ointment (J.P. VIII) is an unique preparation in Japan, which consist of boric acid (5%), zinc oxide (10%), vegetable oil (usually soybean oil or sesame oil) and yellow wax. The ointment is widely used in the area of Hokkaido, because not only of the customary prescription but also of the characteristic clinical efficiency. However, boric acid has been recognized to be harmful in these days. Therefore, a zinc oxide ointment consisting 10% zinc oxide, soybean oil and white beeswax was tentatively made and evaluated. The zinc oxide ointment presented the same consistency as the boric acid and zinc oxide ointment, measured with penetrometer. The clinical efficiency was also confirmed on six patients with chronic eczema and seven patients with psoriasis vulgaris. The effect on wound healing of the donor site of skin graft was as good as the previous preparation. PMID:6629312

Kubota, K; Kumakiri, M; Miura, Y; Hine, K; Kori, N; Saito, H; Miyazaki, K; Arita, T

1983-07-01

48

Effects of aluminum doping and substrate temperature on zinc oxide thin films grown by pulsed laser deposition  

Microsoft Academic Search

Aluminum-doped zinc oxide (AZO) thin films have been deposited on amorphous fused silica substrates by pulsed laser ablation\\u000a of a Zn:Al metallic targets. We varied the film growth condition such as the substrate temperature and Al concentrations.\\u000a The films were deposited at substrate temperatures ranging from 20 to 600°C with oxygen partial pressure of 1 torr. The characteristics\\u000a of the deposited films

Jae Kyu Song; Seung Min Park

2010-01-01

49

Effects of aluminum doping and substrate temperature on zinc oxide thin films grown by pulsed laser deposition  

Microsoft Academic Search

Aluminum-doped zinc oxide (AZO) thin films have been deposited on amorphous fused silica substrates by pulsed laser ablation of a Zn:Al metallic targets. We varied the film growth condition such as the substrate temperature and Al concentrations. The films were deposited at substrate temperatures ranging from 20 to 600°C with oxygen partial pressure of 1 torr. The characteristics of the

Jae Kyu Song; Seung Min Park

2010-01-01

50

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

51

Degradation of azo dyes by oxidative processes--laccase and ultrasound treatment.  

PubMed

Azo dyes are of synthetic origin and their environmental fate is not well understood. They are resistant to direct aerobic bacterial degradation and form potentially carcinogenic aromatic amines by reduction of the azo group. This study shows that applying the oxidative processes of enzymatic treatment with laccase and ultrasound treatment, both alone and in combination, leads to dye degradation. Laccase treatment degraded both Acid Orange and Direct Blue dyes within 1-5 h but failed in the case of Reactive dyes, whereas ultrasound degraded all the dyes investigated (3-15 h). When applied as multi-stage combinations the treatments showed synergistic effects for dye degradation compared with individual treatments. Bulk light absorption (UV-Vis) and ion pairing HPLC were used for process monitoring. Additionally, mass spectrometry was used to elucidate the structures of intermediates arising from ultrasound treatment. PMID:17967530

Tauber, Michael M; Gübitz, Georg M; Rehorek, Astrid

2008-07-01

52

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

53

Thin zinc oxide and cuprous oxide films for photovoltaic applications  

Microsoft Academic Search

Metal oxide semiconductors and heterojunctions made from thin films of metal oxide semiconductors have broad range of functional properties and high potential in optical, electrical and magnetic devices such as light emitting diodes, spintronic devices and solar cells. Among the oxide semiconductors, zinc oxide (ZnO) and cuprous oxide (Cu2O) are attractive because they are inexpensive, abundant and nontoxic. As synthesized

Seongho Jeong

2010-01-01

54

Growth of zinc oxide nanostructures  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) nanowhiskers have been prepared using a multilayer ZnO(50 nm)/Zn(20 nm)/ZnO(2 mum) structure on a polished stainless steel (SS) substrate by high rate magnetron sputtering. The formation of uniformly distributed ZnO nanowhiskers with about 20 nm dia. and 2 to 5 mum length was observed after a post-deposition annealing of the prepared structure at 300-400^{circ}C. An array of highly c-axis oriented ZnO columns (70-300 nm in dia. and up to 10 mum long) were grown on Si substrates by pulsed laser deposition (PLD) at a high pressure (1 Torr), and Raman studies showed the activation of surface phonon modes. The nanosized powder (15-20 nm) and nanoparticle ZnO films on glass substrate were also prepared by a chemical route. Nanowhiskers showed enhanced UV light detection characteristics, and the chemically prepared ZnO nanoparticle films exhibited good sensing properties for alcohol.

Sreenivas, K.; Kumar, Sanjeev; Choudhary, Jaya; Gupta, Vinay

2005-11-01

55

Photo-rewritable flexible LCD using indium zinc oxide/polycarbonate substrates.  

PubMed

This work presents a photo-rewritable transmissive flexible-LCD based on the alignment effect of the photo-induced adsorption of azo dye on flexible indium zinc oxide/polycarbonate (IZO/PC) substrates. Images can be displayed without applying an external field and rewritten by changing the direction of the writing laser beam while the cell temperature is controlled. By using IZO/PC substrates, the writing and erasing processes can be achieved within 1 min with a high contrast. PMID:21221146

Jau, Hung-Chang; Cheng, Ko-Ting; Lin, Tsung-Hsien; Lo, Yuan-Si; Chen, Jia-You; Hsu, Chain-Wen; Fuh, Andy Ying-Guey

2011-01-10

56

Influence of RF power on magnetron sputtered AZO films  

SciTech Connect

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%Al{sub 2}O{sub 3} 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 Multiplication-Sign 10{sup -4}{omega}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. [Semiconductor Thin Films and Plasma Processing Laboratory, Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076 (India)

2013-02-05

57

Influence of different plasma treatments on electrical and optical properties on sputtered AZO and ITO films  

NASA Astrophysics Data System (ADS)

In this paper, the influence of hydrogen and argon plasma treatment on the electro-optical and structural properties of aluminum-doped zinc oxide (AZO) and indium tin oxide (ITO) films were studied. The films were exposed for different times and at various plasma powers. AZO films did not reduce for all plasma conditions, while ITO films were deteriorated when exposed to hydrogen plasma for even a short treatment time. The argon plasma has little effect on the properties of AZO and ITO films. When the ITO films were exposed to Ar plasma for a long time, however, the optical properties of ITO films were strongly influenced.

Lee, Jaehyung; Lim, Donggun; Yang, Keajoon; Choi, Wonseok

2011-07-01

58

Zinc-indium-oxide: A high conductivity transparent conducting oxide  

Microsoft Academic Search

We report the fabrication and characterization of zinc-indium-oxide films with similar electrical conductivity and better transparency in both the visible and infrared compared with indium–tin–oxide, a widely used transparent conductor in many technological applications. Dramatically superior transmission properties in the 1–1.5 ?m range in particular make zinc–indium–oxide attractive for use in infrared devices, where transparent electrodes are required. Resisitivities as

Julia M. Phillips; R. J. Cava; G. A. Thomas; S. A. Carter; J. Kwo; T. Siegrist; J. J. Krajewski; J. H. Marshall; W. F. Peck Jr.; D. H. Rapkine

1995-01-01

59

Pulsed laser deposition of ITO/AZO transparent contact layers for GaN LED applications.  

PubMed

In this study, indium-tin oxide (ITO)/Al-doped zinc oxide (AZO) composite films were fabricated by pulsed laser deposition and used as transparent contact layers (TCLs) in GaN-based blue light emitting diodes (LEDs). The ITO/AZO TCLs were composed of the thin ITO (50 nm) films and AZO films with various thicknesses from 200 to 1000 nm. Conventional LED with ITO (200 nm) TCL prepared by E-beam evaporation was fabricated and characterized for comparison. From the transmittance spectra, the ITO/AZO films exhibited high transparency above 90% at wavelength of 465 nm. The sheet resistance of ITO/AZO TCL decreased as the AZO thickness increased, which could be attributed to the increase in a carrier concentration, leading to a decrease in the forward bias of LED. The LEDs with ITO/AZO composite TCLs showed better light extraction as compared to LED with ITO TCL in compliance with simulation. When an injection current of 20 mA was applied, the output power for LEDs fabricated with ITO/AZO TCLs had 45%, 63%, and 71% enhancement as compared with those fabricated using ITO (200 nm) TCL for the AZO thicknesses of 200, 460, and 1000 nm, respectively. PMID:21934987

Ou, Sin Liang; Wuu, Dong Sing; Liu, Shu Ping; Fu, Yu Chuan; Huang, Shih Cheng; Horng, Ray Hua

2011-08-15

60

Pulsed laser deposition of ITO/AZO transparent contact layers for GaN LED applications  

NASA Astrophysics Data System (ADS)

In this study, indium-tin oxide (ITO)/Al-doped zinc oxide (AZO) composite films were fabricated by pulsed laser deposition and used as transparent contact layers (TCLs) in GaN-based blue light emitting diodes (LEDs). The ITO/AZO TCLs were composed of the thin ITO (50 nm) films and AZO films with various thicknesses from 200 to 1000 nm. Conventional LED with ITO (200 nm) TCL prepared by E-beam evaporation was fabricated and characterized for comparison. From the transmittance spectra, the ITO/AZO films exhibited high transparency above 90 at wavelength of 465 nm. The sheet resistance of ITO/AZO TCL decreased as the AZO thickness increased, which could be attributed to the increase in a carrier concentration, leading to a decrease in the forward bias of LED. The LEDs with ITO/AZO composite TCLs showed better light extraction as compared to LED with ITO TCL in compliance with simulation. When an injection current of 20 mA was applied, the output power for LEDs fabricated with ITO/AZO TCLs had 45%, 63%, and 71% enhancement as compared with those fabricated using ITO (200 nm) TCL for the AZO thicknesses of 200, 460, and 1000 nm, respectively.

Ou, Sin Liang; Wuu, Dong Sing; Liu, Shu Ping; Fu, Yu Chuan; Huang, Shih Cheng; Horng, Ray Hua

2011-08-01

61

The characteristics of chemical and heat stability properties of chromium–vanadium–aluminum co-doped zinc oxide films for dye-sensitized solar cells  

Microsoft Academic Search

Transparent conducting oxide thin films are used as front contact material for dye-sensitized solar cells. This study investigated the effects of chromium (Cr) and vanadium (V) contents on the chemical and heat stability properties of aluminum-doped zinc oxide (AZO) thin films using pulsed direct current magnetic sputtering on Corning 1737F glass substrates. The experimental results show that Cr and V

Y. C. Lin; C. H. Chang; C. H. Shen; P. W. Wang; Y. C. Lee

2010-01-01

62

A Laboratory Comparison of Four Zinc Oxide-Eugenol Formulations as Restorative Materials.  

National Technical Information Service (NTIS)

The ability of four zinc oxide - eugenol formulations to serve as long-term intermediate restorative materials was investigated. They were: (a) zinc oxide - eugenol, (b) zinc oxide - eugenol + EBA (ethoxybenzoic acid), (c) reinforced zinc oxide - eugenol,...

M. D. Jendresen R. W. Phillips M. L. Swartz

1968-01-01

63

Influence of various thickness metallic interlayers on opto-electric and mechanical properties of AZO thin films on PET substrates  

NASA Astrophysics Data System (ADS)

Various thickness metallic interlayers to improve the opto-electric and mechanical properties of aluminum-doped zinc oxide (AZO) thin films deposited on flexible polyethylene terephtalate (PET) substrates are studied. The effects of the interlayers on the resistance and transmittance of the AZO thin films are discussed. The result shows that the metallic interlayers effectively improve the electric resistance but reduce the optical transmittance of the AZO thin films. These phenomena become more obvious as the interlayer thickness increases. However, the AZO with an aluminum interlayer still behaves an acceptable transmittance. Moreover, mechanical tests indicate that the aluminum interlayer increases the hardness and modulus, and reduce the residual stress of the AZO thin films. In contrast, the silver and copper interlayers decrease the AZO's mechanical properties. Comparing to those without any interlayer, the results show that the best interlayer is the 6 nm thick aluminum film.

Chang, R. C.; Li, T. C.; Lin, C. W.

2012-02-01

64

Hydrometallurgical Processes Development for Zinc Oxide Production from Waelz Oxide  

Microsoft Academic Search

This study is focused on the development of a hydrometallurgical process which allows the zinc recovery from Waelz oxide (WO).\\u000a This process is aimed to zinc oxide production. So, it must allow the production of a widely used compound, mainly in tyre\\u000a and ceramics production processes, from industrial residues such as EAF dusts considered as Toxic and Hazardous Wastes (THWs),

D. Herrero; P. L. Arias; J. F. Cambra; N. Antuñano

2010-01-01

65

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

66

A Facile Cu(I)-Catalyzed Oxidative Coupling of Anilines to Azo Compounds and Hydrazines with Diaziridinone under Mild Conditions  

PubMed Central

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.

Zhu, Yingguang; Shi, Yian

2013-01-01

67

Various post-annealing treatments on aluminum doped zinc oxide films fabricated by ion beam co-sputtering  

NASA Astrophysics Data System (ADS)

Aluminum doped zinc oxide (AZO) films with the aluminum concentration of 1.5 at.% were fabricated by co-sputtering dual metallic targets, Al and Zn, under the oxygen partial pressure of 1.3×10-4 torr. The total pressure was kept at 2.3 ×10-4 torr during the deposition. The poly-crystalline structure, optical property and conductivity of the films were investigated by XRD, UV-VIS-IR spectrometer and Hall measurement, respectively. The more intense ZnO crystallinity of (002), larger grain size, smaller d-spacing and highest carrier concentrations were observed on the as deposited AZO film which had the lowest resistivity of 7.8 ×10-4 ?•cm. Comparing the AZO films post-annealed in atmosphere, in vacuum and in hydrogen ambiance, the structures processed in vacuum and hydrogen ambiance remained the good ZnO crystallinity in the film resulting from the oxygen deficient state of the films after post annealing processes. The better thermal stability of resistivity was observed in the films post-annealed in hydrogen ambiance due to the formation of the shallow donor in the film. Furthermore, the resistivity increased as increasing the post-annealing temperature in atmosphere. When the as-deposited film were post-annealed at temperature of 400 °C, the resistivity was about more than two orders of magnitude than that of the as-deposited film resulting from the decrease of the donor concentration and mobility in the AZO film. The variation of the carrier concentration in the AZO film also shifted the energy band gap. However, the average visible transmittance of all AZO films in this study was above 80 % regardless of the deposition and post-annealing conditions.

Hsu, Jin-Cherng; Chen, Yu-Yun; Chiang, Yueh-Sheng; Cho, Heng-Ying

2013-03-01

68

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

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

Photoemission studies of wurtzite zinc oxide.  

NASA Technical Reports Server (NTRS)

The electronic structure of wurtzite zinc oxide, investigated over the widest possible photon energy range by means of photoemission techniques, is described. Of particular interest among the results of the photoemission study are the location of the Zn 3rd core states, the width of the upper valence bands, and structure in the conduction-band and valence-band density of states.

Powell, R. A.; Spicer, W. E.; Mcmenamin, J. C.

1972-01-01

71

Comparable study on the effect of diluted NH 4Cl solution on the postdeposition surface texture of as-deposited aluminum-doped zinc oxide films by direct current pulse and direct current reactive magnetron sputtering  

NASA Astrophysics Data System (ADS)

Effect of 5.0% diluted NH 4Cl aqueous solution was comparably investigated on the postdeposition surface texture of the as-deposited smooth aluminum-doped zinc oxide (AZO) films by direct current pulse reactive magnetron sputtering (DCP-sputtering) and direct current reactive magnetron sputtering (DC-sputtering). The as-deposited AZO films by DCP-sputtering showed an effective surface texture for light trapping upon the etching of 5.0% diluted NH 4Cl solution, while the as-deposited AZO films by DC-sputtering demonstrated an obscure surface texture upon the same etching treatment. The different result might be attributable to a big difference in film strain and film compactness. The formation of interstitial Zn, interstitial Al and grain boundary is the key to realize effective surface texture for the as-deposited AZO films.

Gao, Xiaoyong; Lin, Qinggeng; Feng, Hongliang; Chen, Yongsheng; Yang, Shie; Gu, Jinhua; Li, Weiqiang; Lu, Jingxiao

2009-05-01

72

LPG sensing performance of nanostructured zinc oxide thin films  

NASA Astrophysics Data System (ADS)

Nanostructured zinc oxide thin films were prepared using ultrasonic spray pyrolysis technique. Zinc acetate was used as a starting precursor. As prepared thin films were characterized using different analytical techniques. The sensing performance of the nanostructured zinc oxide thin films was studied on exposure of various gases. The films were observed to be most sensitive (S= 1727) to LPG at 300°C.

Bari, A. R.; Patil, L. A.

2013-06-01

73

Room temperature deposition of alumina-doped zinc oxide on flexible substrates by direct pulsed laser recrystallization  

NASA Astrophysics Data System (ADS)

In this study, a method combining room temperature pulsed laser deposition (PLD) and direct pulsed laser recrystallization (DPLR) is introduced to deposit transparent conductive oxide (TCO) layer on low melting point flexible substrates. Alumina-doped zinc oxide (AZO), as one of the most promising TCO candidates, has now been widely used in solar cells. However, to achieve optimal, electrical, and optical properties of AZO on low melting point, flexible substrate is challenging. DPLR technique is a scalable, economic, and fast process to remove crystal defects and generate recrystallization at room temperature. It features selective processing by only heating up the TCO thin film and preserve the underlying substrate at low temperature. In this study, AZO thin film is pre-deposited by PLD on flexible and rigid substrates. DPLR is then introduced to achieve a uniform TCO layer on these substrates, i.e., commercialized Kapton polyimide film, micron-thick Al-foil, and sold lime glass (SLG). Both finite element analysis simulation and designed experiments are carried out to demonstrate that DPLR is promising in manufacturing high quality AZO layers without any damage to the underlying flexible substrates. The hall mobility of AZO after DPLR on Kapton and SLG reached 198 cm2/v . s and 398 cm2/v . s respectively, while the carrier concentrations are reduced to 2.68 × 1018 and 4.3 × 1019/cm-2, respectively. These characteristics are exactly what an ideal TCO layer should carry: high conductivity and high transmission. The property changes are due to the reduction of defect density after DPLR.

Zhang, Martin Y.; Nian, Qiong; Cheng, Gary J.

2012-04-01

74

Formation of zinc oxide films using submicron zinc particle dispersions  

SciTech Connect

The thermal oxidation of submicron metallic Zn particles was studied as a method to form nanostructured ZnO films. The particles used for this work were characterized by electron microscopy, x-ray diffraction and thermal analysis to evaluate the Zn-ZnO core shell structure, surface morphology, and oxidation characteristics. Significant nanostructural changes were observed for films annealed to 400 °C or higher, where nanoflakes, nanoribbons, nanoneedles and nanorods were formed as a result of stress induced fractures arising in the ZnO outer shell due to differential thermal expansion between the metallic Zn core and the ZnO shell. Mass transport occurs through these defects due to the high vapor pressure for metallic Zn at temperatures above 230 °C, whereupon the Zn vapor rapidly oxidizes in air to form the ZnO nanostructures. The Zn particles were also incorporated into zinc indium oxide precursor solutions to form thin film transistor test structures to evaluate the potential of forming nanostructured field effect sensors using simple solution processing.

Rajachidambaram, Meena Suhanya; Varga, Tamas; Kovarik, Libor; Sanghavi, Rahul P.; Shutthanandan, V.; Thevuthasan, Suntharampillai; Han, Seungyeol; Chang, Chih-hung; Herman, Gregory S.

2012-07-27

75

Doping in zinc oxide thin films  

Microsoft Academic Search

Doping in zinc oxide (ZnO) thin films is discussed in this dissertation. The optimizations of undoped ZnO thin film growth using molecular-beam epitaxy (MBE) are discussed. The effect of the oxygen ECR plasma power on the growth rate, structural, electrical, and optical properties of the ZnO thin films were studied. It was found that larger ECR power leads to higher

Zheng Yang

2009-01-01

76

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) [Cary, NC; Turk, Brian Scott (Durham, NC) [Durham, NC; Gupta, Raghubir Prasad (Durham, NC) [Durham, NC

2011-06-07

77

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

2013-11-01

78

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

79

Summary Review of Health Effects Associated with Zinc and Zinc Oxide: Health Issue Assessment.  

National Technical Information Service (NTIS)

Zinc is a dense, bluish-white, relatively soft metal used extensively in the galvanizing of iron and steel. Zinc oxide, the most valued of the variety of compounds formed by zinc is used principally in rubber products as an activator in the vulcanization ...

1987-01-01

80

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

81

Photo?assisted hetero?Fenton decolorization of azo dye from contaminated water by Fe–Si mixed oxide nanocomposite  

Microsoft Academic Search

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 °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

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

2011-01-01

82

Synthesis and Photocatalytic Activity of Doped Zinc Oxide Nanoparticles  

Microsoft Academic Search

In this study, we have investigated the effect of doping with cobalt and manganese oxide on the photocatalytic activity of nanoparticulate zinc oxide. Zinc oxide powders with controlled particle size, minimal agglomeration, and controlled chemical composition were manufactured by mechanochemical processing. The photocatalytic activity of the powders was measured using the spin trapping technique with electron paramagnetic resonance spectroscopy. It

Aaron Dodd; Allan McKinley; Martin Saunders; Takuya Tsuzuki

2006-01-01

83

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

84

Preparation and Use of Nano Zinc Oxide in Neoprene Rubber  

Microsoft Academic Search

Zinc oxide (ZnO) of nanometer particle size was prepared by solid-state pyrolytic method. TEM, XRD, and surface area studies showed that the prepared zinc oxide had particle size in the range of 15–30 nm and surface area in the range of 12–30 m\\/g. This nano zinc oxide was used as a curing agent in neoprene rubber. The optimum dosage of ZnO was

P. M. Sabura Begum; K. K. Mohammed Yusuff; Rani Joseph

2008-01-01

85

Defects in zinc oxide nanocrystals  

NASA Astrophysics Data System (ADS)

Defects in ZnO nanocrystals were investigated. While ZnO has potential for optoelectronic applications, the lack reliable p-type doping remains a major challenge. We provide evidence that ZnO nanocrystals contain uncompensated acceptors. IR absorption peaks at liquid-helium temperatures suggest a hydrogenic acceptor with a hole binding energy of 0.4 - 0.5 eV. Electron paramagnetic resonance (EPR) measurements in the dark showed a resonance at g = 2.003, characteristic of acceptors that involve a zinc vacancy. An EPR resonance due to vacancy hydrogen complexes was observed after exposure to light. Using infrared (IR) and photoluminescence (PL) spectroscopy, we have developed a unified model for the acceptor and intragap surface states of ZnO nanocrystals. A PL peak was observed at 2.97 eV, in agreement with the acceptor level observed in the IR. The temperature dependence of the IR absorption peaks, which correspond to a hole binding energy of 0.46 eV, showed an ionization activation energy of only 0.08 eV. This activation energy is attributed to thermal excitation of the hole to surface states 0.38 eV above the valence band maximum. Therefore, while the acceptor is deep with respect to the bulk valence band, it is shallow with respect to surface states. A strong red PL emission centered at 1.84 eV, with an excitation onset of 3.0 eV, is attributed to surface recombination. IR absorption peaks at liquid-helium temperatures, which correspond to electronic transitions of the acceptor, disappeared after exposure to formic acid (HCOOH) vapor. This observation is consistent with electrical compensation of the acceptor by the formate ion. The energy level of the formate ion is estimated to be ˜ 0.9 eV above the valence-band maximum. Room temperature IR measurements show that the formate species are adsorbed on the surface of ZnO nanocrystals. A broad PL peak centered at 3.2 eV, for samples exposed to HCOOH, is attributed to an exciton bound to a formate species. High field EPR measurements of ZnO nanocrystals showed new resonances, in addition to the previously observed line at g = 2.003. We propose a model of two systems with an axial center of g ? = 2.003274 and g? = 2.007471 along with an isotropic center at g = 2.005254. Samples exposed to HCOOH did not show a complete disappearance of the EPR resonances. Instead, a decrease in intensity is observed.

Teklemichael, Samuel Tesfai

86

Active manganese oxide: a novel adsorbent for treatment of wastewater containing azo dye.  

PubMed

A new variety of active manganese oxide was prepared, characterized, and tested for its potential of adsorbing Congo Red, a dis-azo dye, from aqueous solutions. Both equilibrium and kinetics were investigated over different values of process parameters such as temperature (25-45 degrees C), adsorbent loading (0.4-0.6%), initial dye concentration (50-500 mg/L), presence of salts (sodium sulphate, 500 mg/L) and the oxygen content (MnO(x), x=1.2, 1.33 and 2) of the adsorbent. The equilibrium adsorption data were fitted to Langmuir and Freundlich isotherms. Langmuir adsorption capacity of the sorbent (x=1.33) for Congo Red was 38.6 mg/g at room temperature which is substantially higher than those for commercial manganese dioxide, red mud, coir pith, activated carbon, and fly ash. The kinetic data were best interpreted using a pseudo-second order model. The results show that the active manganese oxide used in this work removes the dye by reversible adsorption and has the potential for practical use for remediation of textile industry effluents. PMID:19955624

Chakrabarti, S; Dutta, B K; Apak, R

2009-01-01

87

Electro-oxidation of two reactive azo dyes on boron-doped diamond electrode.  

PubMed

Electrochemical oxidation (decolorization/degradation) of blue and red commercial reactive azo dyes was carried out on boron-doped diamond (BDD) electrode. The effect of various quantities of FeSO(4) was investigated in the electro-Fenton reaction on BDD. Progress of dyes degradation during the electrolysis and electro-Fenton reaction was monitored by UV-visible absorption and by estimation of the chemical oxygen demand (COD). Direct electrolysis showed a limiting capacity for red and blue dye removal even at high current densities, e.g. maximum red color and COD removal were 70 and 20%, respectively at 30 mA cm(-2) after 300 min. Higher red and blue color removal efficiencies were achieved by electro-Fenton oxidation. Current density of 30 mA cm(-2) in the presence of 0.05 mmol/L of FeSO(4) resulted in the red color and COD removal of 98 and 96%, respectively. The optimum FeSO(4) concentration for the electro-Fenton reaction was determined to be 0.05 mmol/L. Instantaneous current efficiency (ICE) in the presence of FeSO(4) was almost three times higher than for experiments carried out without FeSO(4). PMID:22744674

Almomani, Fares; Baranova, Elena A

2012-01-01

88

Zinc absorption by young adults from supplemental zinc citrate is comparable with that from zinc gluconate and higher than from zinc oxide.  

PubMed

The water-soluble zinc salts gluconate, sulfate, and acetate are commonly used as supplements in tablet or syrup form to prevent zinc deficiency and to treat diarrhea in children in combination with oral rehydration. Zinc citrate is an alternative compound with high zinc content, slightly soluble in water, which has better sensory properties in syrups but no absorption data in humans. We used the double-isotope tracer method with (67)Zn and (70)Zn to measure zinc absorption from zinc citrate given as supplements containing 10 mg of zinc to 15 healthy adults without food and compared absorption with that from zinc gluconate and zinc oxide (insoluble in water) using a randomized, double-masked, 3-way crossover design. Median (IQR) fractional absorption of zinc from zinc citrate was 61.3% (56.6-71.0) and was not different from that from zinc gluconate with 60.9% (50.6-71.7). Absorption from zinc oxide at 49.9% (40.9-57.7) was significantly lower than from both other supplements (P < 0.01). Three participants had little or no absorption from zinc oxide. We conclude that zinc citrate, given as a supplement without food, is as well absorbed by healthy adults as zinc gluconate and may thus be a useful alternative for preventing zinc deficiency and treating diarrhea. The more insoluble zinc oxide is less well absorbed when given as a supplement without food and may be minimally absorbed by some individuals. This trial was registered at clinicaltrials.gov as NCT01576627. PMID:24259556

Wegmüller, Rita; Tay, Fabian; Zeder, Christophe; Brnic, Marica; Hurrell, Richard F

2014-02-01

89

The relationship of etching behavior and crystal orientation of aluminum doped zinc oxide films  

NASA Astrophysics Data System (ADS)

Aluminum doped zinc oxide (AZO) transparent conducting films were dynamically deposited on corning glass substrates in an in-line sputtering system operated at mid-frequency sputtering mode with excitation frequency of 40 kHz. This study addressed the surface structure as well as the electrical and optical properties after wet-chemical etching. With the increase of substrate temperature, the dominant orientation of the as-deposited films changes from (0 0 2) to (1 0 3). After wet-chemical etching, due to the quick etching rate of the (0 0 2) plane relative to the (1 0 3) plane, the surface morphology of the films deposited at different temperatures show a transition from craterlike to granular surface morphology. The experimental results demonstrate that the crystal orientation of the as-deposited films plays an important role for the etching behavior of the films.

Ding, J. N.; Ye, F.; Yuan, N. Y.; Tan, C. B.; Zhu, Y. Y.; Ding, G. Q.; Chen, Z. H.

2010-12-01

90

Nanocrystalline copper doped zinc oxide produced from copper doped zinc hydroxide nitrate as a layered precursor  

Microsoft Academic Search

Undoped and copper doped nanostructured zinc oxides were synthesized by using a series of synthetic layered material, undoped and copper doped zinc hydroxide nitrates at various molar percentages of copper (2–10) within the layers as precursors. The layered materials were heat-treated at 500°C to produce zinc oxide nanostructures with crystallite sizes in the range of 23–35nm. Optical studies of the

Mohammad Yeganeh Ghotbi; Narjes Bagheri; S. K. Sadrnezhaad

91

Properties of ITO-AZO bilayer thin films prepared by magnetron sputtering for applications in thin-film silicon solar cells  

NASA Astrophysics Data System (ADS)

In this paper we study the electro-optical behavior and the application of indium-tin oxide (ITO) and aluminum-doped zinc oxide (AZO) bilayer thin films for silicon solar cells. ITO-AZO bilayer thin films were deposited on glass substrates using radio-frequency magnetron sputtering. The experimental results show that a decrease in the electrical resistivity of the ITO-AZO bilayer thin films has been achieved without significant degradation of optical properties. In the best case the resistivity of the bilayer films reached a minimum of 5.075×10-4 ? cm when the thickness of the AZO buffer layer was 12 nm. The ITO-AZO bilayer films were applied as the front electrodes of amorphous silicon solar cells and the short-circuit current density of the solar cells was considerably increased.

Wang, Chao; Mao, Yanli; Zeng, Xiangbo

2013-01-01

92

Annealing and oxidation mechanism of evaporated zinc thin films from zinc oxide powder  

Microsoft Academic Search

Zinc oxide (ZnO) thin films were deposited by thermal evaporation of a high quality ZnO powder; the obtained films were then oxidized in the air. We have systematically investigated the influence of annealing temperature ranged from 100 to 400°C on the films composition and structural and optical properties by using Rutherford Back Scattering (RBS) analysis, X-ray Diffraction (XRD) and UV–Visible

M. S. Aida; E. Tomasella; J. Cellier; M. Jacquet; N. Bouhssira; S. Abed; A. Mosbah

2006-01-01

93

Zinc oxide nanowire networks for macroelectronic devices  

NASA Astrophysics Data System (ADS)

Highly transparent zinc oxide (ZnO) nanowire networks have been used as the active material in thin film transistors (TFTs) and complementary inverter devices. A systematic study on a range of networks of variable density and TFT channel length was performed. ZnO nanowire networks provide a less lithographically intense alternative to individual nanowire devices, are always semiconducting, and yield significantly higher mobilites than those achieved from currently used amorphous Si and organic TFTs. These results suggest that ZnO nanowire networks could be ideal for inexpensive large area electronics.

Unalan, Husnu Emrah; Zhang, Yan; Hiralal, Pritesh; Dalal, Sharvari; Chu, Daping; Eda, Goki; Teo, K. B. K.; Chhowalla, Manish; Milne, William I.; Amaratunga, Gehan A. J.

2009-04-01

94

Recent developments in zinc oxide target chemistry  

SciTech Connect

Zinc oxide targets irradiated with high energy protons at the Los Alamos Meson Physics Facility (LAMPF) contain a number of radioactive spallation products in quantities large enough to warrant recovery. This paper describes methods for recovering {sup 7}Be, {sup 46}Sc, and {sup 48}V from such targets and offers suggestions on possible ways to recover additional isotopes. The proposed methods are based on traditional precipitation and ion exchange techniques, are readily adaptable to hot cell use, and produce no hazardous waste components. The products are obtained in moderate to high yields and have excellent radiopurity.

Heaton, R.C.; Taylor, W.A.; Phillips, D.R.; Jamriska, D.J. Sr.; Garcia, J.B.

1994-04-01

95

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

96

An Electron Paramagnetic Resonance Study of Indium Doped Zinc Oxide.  

National Technical Information Service (NTIS)

Samples of zinc oxide doped with indium have been prepared using the vapor transport method. Concentration of dopant is controlled by appropriate mixing of the oxides of indium and zinc. When ZnO is mechanically damaged, three lines in the EPR spectrum wi...

C. van der Schroeff

1973-01-01

97

Zinc oxide microcapsules obtained via a bio-inspired approach  

Microsoft Academic Search

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

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

2007-01-01

98

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

SciTech Connect

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 (T{sub s}). The films were found to be crystalline with the electrical resistivity close to 1.1 × 10{sup ?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 T{sub s} 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. [Center for Materials Research, Norfolk State University, 700 Park Avenue, Norfolk, Virginia 23504 (United States)] [Center for Materials Research, Norfolk State University, 700 Park Avenue, Norfolk, Virginia 23504 (United States)

2013-10-14

99

Preparation of Naturally Textured Aluminum-Doped Zinc Oxide Films on Flexible Poly(ether sulfone) Substrate by Radio Frequency Magnetron Sputtering  

NASA Astrophysics Data System (ADS)

Transparent conducting oxide (TCO) layers of naturally textured aluminum-doped zinc oxide (AZO) were prepared on flexible poly(ether sulfone) (PES) substrates by controlling the radio frequency (RF) magnetron sputtering power without chemical wet etching, and their morphological, optical, and electrical properties were characterized. Layers with crater structures were formed at a single RF power; whereas at high RF power (2000 W), their surfaces resembled that of chemically wet-etched AZO. Layers were also formed by dual RF sputtering powers: sputtering a 0.15-?m-thick layer at high power and a subsequent 0.45-?m-thick layer at low power produced flakes with larger grains or crater-like structures. The measured visible transmittance of all the layers was >85% --- sufficient for use in amorphous silicon (a-Si) thin-film solar cells. The measured optical and electrical properties of the naturally textured AZO layers are comparable to those of chemically wet-etched AZO layers, suggesting a possible method for fabricating inexpensive flexible a-Si thin-film solar cells in fewer steps.

An, Jae Seok; Shin, Jin Koog; Lee, Jong Ho; Choi, Bum Ho

2013-03-01

100

Zinc oxide nanomaterials for biomedical fluorescence detection.  

PubMed

One-dimensional zinc oxide nanomaterials have been recently developed into novel, extremely effective, optical signal-enhancing bioplatforms. Their usefulness has been demonstrated in various biomedical fluorescence assays. Fluorescence is extensively used in biology and medicine as a sensitive and noninvasive detection method for tracking and analyzing biological molecules. Achieving high sensitivity via improving signal-to-noise ratio is of paramount importance in fluorescence-based, trace-level detection. Recent advances in the development of optically superior one-dimensional materials have contributed to this important biomedical area of detection. This review article will discuss major research developments that have so far been made in this emerging and exciting topical field. The discussion will cover a broad range of subjects including synthesis of zinc oxide nanorods (ZnO NRs), various properties differentiating them as suitable optical biodetection platforms, their demonstrated applicability in DNA and protein detection, and the nanomaterial characteristics relevant for biomolecular fluorescence enhancement. This review will then summarize the current status of ZnO NR-based biodetection and further elaborate future utility of ZnO NR platforms for advanced biomedical assays, based on their proven advantages. Lastly, present challenges experienced in this topical area will be identified and focal subject areas for future research will be suggested as well. PMID:24730276

Hahm, Jong-In

2014-01-01

101

Mechanism of conductivity degradation of AZO thin film in high humidity ambient  

NASA Astrophysics Data System (ADS)

The conductivity stability of aluminum-doped zinc oxide (AZO) films was evaluated in the ambient with different humidity. We found that the conductivity of AZO films is sensitive to the humidity and degrades remarkably in high humidity ambient (90 ± 5% relative humidity) at 60 °C. Hall measurement results show that the conductivity degradation is due to the drop in the carrier concentration, while the carrier mobility is found to remain relatively constant in the high humidity ambient. XPS (X-ray photoelectron spectroscopy) analysis reveals that the oxygen-vacancies in the AZO thin films were greatly reduced in the high-humidity ambient. So, we believe that the high-humidity ambient causes the decrease in the oxygen vacancies and eventually resulted in the decrease in the concentration of the free carriers in the AZO thin films. In this study, a mechanism is proposed to explain the humidity-assist reduction in the oxygen vacancies in the humidity-tested AZO films. In addition, we report that the electrical properties of AZO film can be stabilized by coating a Cr layer on the AZO thin film surface.

Liu, Yen-Shuo; Hsieh, Chih-Yi; Wu, Yen-Ju; Wei, Yu-Shan; Lee, Po-Ming; Hsieh, Hsiu-Ming; Liu, Cheng-Yi

2013-10-01

102

Broadband wide-angle antireflection enhancement in AZO/Si shell/core subwavelength grating structures with hydrophobic surface for Si-based solar cells.  

PubMed

Broadband wide-angle antireflection characteristics of aluminum-doped zinc oxide (AZO)/silicon (Si) shell/core subwavelength grating (SWG) structures with a hydrophobic surface, together with theoretical prediction using a rigorous coupled-wave analysis simulation, were investigated for Si-based solar cells. The AZO films with different thicknesses were deposited on Si SWGs by rf magnetron sputtering method, which forms a shell/core structure. The AZO/Si shell/core SWGs reduced significantly the surface reflection compared to the AZO films/Si substrate. The coverage of AZO films on Si SWGs improved the antireflective property over a wider incident angle. The AZO/Si shell/core SWG structure with a 200 nm-thick AZO layer deposited at an rf power of 200 W exhibited a water contact angle of 123°. This structure also exhibited a low average reflectance of ~2% over a wide wavelength range of 300-2100 nm with a solar weighted reflectance of 2.8%, maintaining a reflectance of < 9.2% at wavelengths of 300-2100 nm up to the incident angle of ?(i) = 70°. The effective electrical properties of AZO films in AZO/Si shell/core SWGs were also analyzed. PMID:21935259

Leem, Jung Woo; Song, Young Min; Yu, Jae Su

2011-09-12

103

Transparent indium zinc oxide ohmic contact to phosphor-doped n-type zinc oxide  

Microsoft Academic Search

Transparent indium zinc oxide (IZO) ohmic contacts to phosphor-doped n-type ZnO have been formed. The resistance, transmittance, and phase reliability of the contacts were investigated. As deposited, an ohmic contact was formed with a specific contact resistance of about 1.1×10-4 Omega cm2 and the transmittance of the ZnO\\/IZO (520\\/350 nm) film was more than 75% in the 450-1100 nm wavelength

Guangxia Hu; Bhupendra Kumar; Hao Gong; E. F. Chor; Ping Wu

2006-01-01

104

Production of nano zinc, zinc sulphide and nanocomplex of magnetite zinc oxide by Brevundimonas diminuta and Pseudomonas stutzeri.  

PubMed

ZnO (Zincite) nanoparticle has many industrial applications and is mostly produced by chemical reactions, usually prepared by decomposition of zinc acetate or hot-injection and heating-up method. Synthesis of semi-conductor nanoparticles such as ZnS (Sphalerite) by ultrasonic was previously reported. In this work, high-zinc tolerant bacteria were isolated and used for nano zinc production. Among all isolated microorganisms, a gram negative bacterium which was identified as Brevundimonas diminuta could construct nano magnetite zinc oxide on bacterial surface with 22 nm in size and nano zinc with 48.29 nm in size. A piece of zinc metal was immersed in medium containing of pure culture of B. diminuta. Subsequently, a yellow-white biofilm was formed which was collected from the surface of zinc. It was dried at room temperature. The isolated biofilm was analysed by X-ray diffractometer. Interestingly, the yield of these particles was higher in the light, with pH 7 at 23°C. To the best of the authors knowledge, this is the first report about the production of nano zinc metal and nano zinc oxide that are stable and have anti-bacterial activities with magnetite property. Also ZnS (sized 12 nm) produced by Pseudomonas stutzeri, was studied by photoluminescence and fluorescent microscope. PMID:24206770

Mirhendi, Mansoureh; Emtiazi, Giti; Roghanian, Rasoul

2013-12-01

105

Characterization of P-type zinc oxide films  

Microsoft Academic Search

Zinc Oxide falls under the classification of transparent conductive oxides. They typical optical transmittance of Zinc Oxide is 90% in the visible wavelength region. Though stoichiometric ZnO is an insulator, due to the presence of internal defects such as Zn interstitials and Oxygen vacancies, it exists as a n-type conductor. The other important property of ZnO which could be used

Madhavi Oleti Kalki Rajan

2004-01-01

106

Photocatalytic paper using zinc oxide nanorods  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) nanorods were grown on a paper support prepared from soft wood pulp. The photocatalytic activity of a sheet of paper with ZnO nanorods embedded in its porous matrix has been studied. ZnO nanorods were firmly attached to cellulose fibers and the photocatalytic paper samples were reused several times with nominal decrease in efficiency. Photodegradation of up to 93% was observed for methylene blue in the presence of paper filled with ZnO nanorods upon irradiation with visible light at 963 Wm-2 for 120 min. Under similar conditions, photodegradation of approximately 35% was observed for methyl orange. Antibacterial tests revealed that the photocatalytic paper inhibits the growth of Escherichia coli under room lighting conditions.

Baruah, Sunandan; Jaisai, Mayuree; Imani, Reza; Nazhad, Mousa M.; Dutta, Joydeep

2010-10-01

107

Rapid synthesis of aligned zinc oxide nanowires.  

PubMed

A solution growth approach for zinc oxide (ZnO) nanowires is highly appealing because of the low growth temperature and possibility for large area synthesis. Reported reaction times for ZnO nanowire synthesis, however, are long, spanning from several hours to days. In this work, we report on the rapid synthesis of ZnO nanowires on various substrates (such as poly(ethylene terephthalate) (PET), silicon and glass) using a commercially available microwave oven. The average growth rate of our nanowires is determined to be as high as 100 nm min(-1), depending on the microwave power. Transmission electron microscopy analysis revealed a defect-free single-crystalline lattice of the nanowires. A detailed analysis of the growth characteristics of ZnO nanowires as functions of growth time and microwave power is reported. Our work demonstrates the possibility of a fast synthesis route using microwave heating for nanomaterials synthesis. PMID:21828660

Unalan, Husnu Emrah; Hiralal, Pritesh; Rupesinghe, Nalin; Dalal, Sharvari; Milne, William I; Amaratunga, Gehan A J

2008-06-25

108

Hydrothermal Sulfidation and Flotation of Oxidized Zinc-Lead Ore  

NASA Astrophysics Data System (ADS)

The sample with smithsonite and cerussite as the main valuable metal minerals is a carbonate-hosted lead-zinc ore in the current study. Hydrothermal sulfidation of oxidized zinc-lead ore was carried out with a particle size of 74 to 58 ?m and the mole ratio of sulfur and zinc of 2.0 at 453 K (180 °C) for 240 minutes, and 73 pct zinc and 86 pct lead sulfidation fraction were achieved. Flotation of the unsulfided sample was ineffective, with less than 55 pct recovery of zinc and lead. After sulfidation, the recoveries of zinc and lead in flotation concentrate were over 92 pct. A flotation concentrate was obtained with zinc and lead content of 41.2 pct and 22.1 pct, respectively.

Li, Cun-Xiong; Wei, Chang; Deng, Zhi-Gan; Li, Xing-Bin; Li, Min-Ting; Xu, Hong-Sheng

2014-06-01

109

Optical and electric properties of aluminum-gallium doped zinc oxide for transparent conducting film  

Microsoft Academic Search

The well-known indium-tin-oxide is not suitable for solar cell, because of the chemical reduction, even without any hydrogen dilution. The inexpensive and non-toxic of transparent conducting Aluminum and Gallium doped ZnO (AZO and GZO) thin films have been investigated for the substitutes for the indium-tin-oxide thin films. AZO performs high transmittance at visible region, however, higher resistance than GZO. In

Meng-Chi Li; Chien-Cheng Kuo; Sheng-Hui Chen; Cheng-Chung Lee

2009-01-01

110

Copper(II)-catalyzed room temperature aerobic oxidation of hydroxamic acids and hydrazides to acyl-nitroso and azo intermediates, and their Diels-Alder trapping.  

PubMed

CuCl(2), in the presence of a 2-ethyl-2-oxazoline ligand, is an effective catalyst for the room temperature, aerobic oxidation of hydroxamic acids and hydrazides, to acyl-nitroso and azo dienophiles respectively, which are efficiently trapped in situ via both inter- and intramolecular hetero-Diels-Alder reactions with dienes. Both inter- and intramolecular variants of the Diels-Alder reaction are suitable under the reaction conditions using a variety of solvents. Under the same conditions, an acyl hydrazide was also oxidized to give an acyl-azo dienophile which was trapped intramolecularly by a diene. PMID:21644530

Chaiyaveij, Duangduan; Cleary, Leah; Batsanov, Andrei S; Marder, Todd B; Shea, Kenneth J; Whiting, Andrew

2011-07-01

111

Nanocrystal indium doped zinc oxide prepared by spray pyrolysis method  

Microsoft Academic Search

Thin films of indium-doped zinc oxide have been prepared by spray pyrolysis of the methanol solution of zinc acetate on heated substrates. As prepared films show hexagonal wurtzite nanocrystal structure. The films have 90 % transmission for wavelength more than 550 nm, but the conductivity depends from the indium doping. Thickness of 500 nm of the films was estimated from

A. Tanusevski; M. Ristova; M. Ristov; V. Georgieva

2007-01-01

112

Diffusion of zinc vacancies and interstitials in zinc oxide  

NASA Astrophysics Data System (ADS)

The self-diffusion coefficient of zinc in ZnO is derived as a function of the chemical potential and Fermi level from first-principles calculations. Density functional calculations in combination with the climbing image-nudged elastic band method are used in order to determine migration barriers for vacancy, interstitial, and interstitialcy jumps. Zinc interstitials preferentially diffuse to second nearest neighbor positions. They become mobile at temperatures as low as 90-130 K and therefore allow for rapid defect annealing. Under predominantly oxygen-rich and n-type conditions self-diffusion occurs via a vacancy mechanism.

Erhart, Paul; Albe, Karsten

2006-05-01

113

Copper(II), nickel(II), cobalt(II) and zinc(II) complexes of 2-[2-(6-methylbenzothiazolyl)azo]-5-dimethylaminobenzoic acid: synthesis, spectral, thermal and molecular modelling studies  

Microsoft Academic Search

Complexes of copper(II), nickel(II), cobalt(II), and zinc(II) with 2-[2-(6-methylbenzothiazolyl)azo]-5-dimethylaminobenzoic acid have been prepared and characterized by elemental analysis, vibrational spectra, magnetic susceptibility measurements, conductance measurements and e.p.r. spectra. Stability constants have been evaluated potentiometrically. Electronic spectra, magnetic susceptibility measurements and molecular modeling studies support a distorted square planar geometry around the metal ions. Vibrational spectra indicate the coordination of the

Bhagwan S. Garg; Rakesh K. Sharma; Ekta Kundra

2005-01-01

114

Bioavailability of Zinc in Wistar Rats Fed with Rice Fortified with Zinc Oxide  

PubMed Central

The study of zinc bioavailability in foods is important because this mineral intake does not meet the recommended doses for some population groups. Also, the presence of dietary factors that reduce zinc absorption contributes to its deficiency. Rice fortified with micronutrients (Ultra Rice®) is a viable alternative for fortification since this cereal is already inserted into the population habit. The aim of this study was to evaluate the bioavailability of zinc (Zn) in rice fortified with zinc oxide. During 42 days, rats were divided into four groups and fed with diets containing two different sources of Zn (test diet: UR® fortified with zinc oxide, or control diet: zinc carbonate (ZnCO3)), supplying 50% or 100%, respectively, of the recommendations of this mineral for animals. Weight gain, food intake, feed efficiency ratio, weight, thickness and length of femur; retention of zinc, calcium (Ca) and magnesium (Mg) in the femur and the concentrations of Zn in femur, plasma and erythrocytes were evaluated. Control diet showed higher weight gain, feed efficiency ratio, retention of Zn and Zn concentration in the femur (p < 0.05). However, no differences were observed (p > 0.05) for dietary intake, length and thickness of the femur, erythrocyte and plasmatic Zn between groups. Although rice fortified with zinc oxide showed a lower bioavailability compared to ZnCO3, this food can be a viable alternative to be used as a vehicle for fortification.

Della Lucia, Ceres Mattos; Santos, Laura Luiza Menezes; Rodrigues, Kellen Cristina da Cruz; Rodrigues, Vivian Cristina da Cruz; Martino, Hercia Stampini Duarte; Pinheiro Sant'Ana, Helena Maria

2014-01-01

115

Bioavailability of zinc in wistar rats fed with rice fortified with zinc oxide.  

PubMed

The study of zinc bioavailability in foods is important because this mineral intake does not meet the recommended doses for some population groups. Also, the presence of dietary factors that reduce zinc absorption contributes to its deficiency. Rice fortified with micronutrients (Ultra Rice®) is a viable alternative for fortification since this cereal is already inserted into the population habit. The aim of this study was to evaluate the bioavailability of zinc (Zn) in rice fortified with zinc oxide. During 42 days, rats were divided into four groups and fed with diets containing two different sources of Zn (test diet: UR® fortified with zinc oxide, or control diet: zinc carbonate (ZnCO3)), supplying 50% or 100%, respectively, of the recommendations of this mineral for animals. Weight gain, food intake, feed efficiency ratio, weight, thickness and length of femur; retention of zinc, calcium (Ca) and magnesium (Mg) in the femur and the concentrations of Zn in femur, plasma and erythrocytes were evaluated. Control diet showed higher weight gain, feed efficiency ratio, retention of Zn and Zn concentration in the femur (p < 0.05). However, no differences were observed (p > 0.05) for dietary intake, length and thickness of the femur, erythrocyte and plasmatic Zn between groups. Although rice fortified with zinc oxide showed a lower bioavailability compared to ZnCO3, this food can be a viable alternative to be used as a vehicle for fortification. PMID:24932657

Della Lucia, Ceres Mattos; Santos, Laura Luiza Menezes; da Cruz Rodrigues, Kellen Cristina; da Cruz Rodrigues, Vivian Cristina; Martino, Hércia Stampini Duarte; Sant'Ana, Helena Maria Pinheiro

2014-01-01

116

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

117

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

2014-04-01

118

Toxicokinetics of zinc oxide nanoparticles in rats  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) nanoparticle have been extensively applied to diverse industrial fields because they possess UV light absorption, catalytic, semi-conducting, and magnetic characteristics as well as antimicrobial property. However, up to date, toxicological effects of ZnO nanoparticles in animal models have not been completely determined. Moreover, little information is available about kinetic behaviors of ZnO nanoparticles in vivo, which will be crucial to predict their potential chronic toxicity after long-term exposure. The aim of this study was, therefore, to evaluate the pharmacokinetics and toxicokinetics of ZnO nanoparticles after single-dose and repeated dose 90-day oral administration in male and female rats, respectively. The blood samples were collected following administration of three different doses (125, 250, and 500 mg/kg) and ZnO concentration was assessed by measuring zinc level with inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The result showed that the plasma ZnO concentration significantly increased in a dose-dependent manner, but decreased within 24 h after single-dose oral administration up to 500 mg/kg, without any significant difference between gender. However, when repeated dose 90-day oral toxicity study was performed, the elevated plasma concentrations did not return to normal control levels in all the cases, indicating their toxicity potential. These findings suggest that repeated oral exposure to ZnO nanoparticles up to the dose of 125 mg/kg could accumulate in the systemic circulation, thereby implying that the NOAEL values could be less than 125 mg/kg via oral intake.

Chung, H. E.; Yu, J.; Baek, M.; Lee, J. A.; Kim, M. S.; Kim, S. H.; Maeng, E. H.; Lee, J. K.; Jeong, J.; Choi, S. J.

2013-04-01

119

Low-index metamaterials comprised of plasmonic dimers of aluminum-doped zinc oxide  

NASA Astrophysics Data System (ADS)

Transparent conducting oxides (TCO) are an interesting class of plasmonic materials, which are under intensive study for their use in low-loss metamaterials and a range of applications such as sensing, imaging and transformation optics. Here, using both full-wave simulations and an equivalent circuit model for pairs of nanoparticles of aluminum doped zinc oxide (AZO), we study the plasmonic effects for low loss low index metamaterials for infrared applications. The behavior of localized surface plasmon resonances (LSPR) of AZO nanoparticle dimers embedded in a host polymer medium is investigated for different dimer orientations with respect to the indicent electromagnetic wave. In doing this, the role of dressed polarizability to enhance and quench the plasmonic effects is also considered. The effects of the nanoparticles relative size and the spacing between them are studied. Understanding these resonances and their dependence on dimer orientations, provides a means to design metamaterial structures for use in the near infrared (NIR) region with epsilon-near-zero properties leading also to low index metamaterials. In our studies, we demonstrate how nanospheres with radii less than 100 nm that are distributed with an average spacing less than their diameter, can result in an effective medium with refractive index less than one. We utilize a full-wave frequency domain finite element method in conjunction with an equivalent-circuit model for the nanoscale dimers in order to describe the spectral response of the bulk low index properties. We also present a statistical analysis to obtain the effective refractive index for incident light having different polarizations.

Alisafaee, Hossein; Cox, P. M.; Fiddy, Michael A.

2013-09-01

120

Surface States Associated with Chemisorbed Species on Zinc Oxide.  

National Technical Information Service (NTIS)

The paper introduces a new method for measuring electronic energy levels (surface states) associated with foreign species on zinc oxide and describes early results. The method is based on electrostatic charging from the gas phase. The surface is shifted f...

S. R. Morrison

1968-01-01

121

Nano-sized layered aluminium or zinc-manganese oxides as efficient water oxidizing catalysts.  

PubMed

Nano-sized layered aluminium or zinc-manganese oxides were synthesized and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrometry, dynamic light scattering and atomic absorption spectroscopy. These oxides showed efficient water oxidizing activity in the presence of cerium(IV) ammonium nitrate as a non-oxo transfer oxidant. Amounts of dissolved manganese, zinc or aluminium, and water oxidation activities of these oxides were reported and compared with other manganese oxides. A mechanism for oxygen evolution and possible roles for zinc or aluminium ions are also proposed. PMID:22565665

Najafpour, Mohammad Mahdi; Pashaei, Babak; Nayeri, Sara

2012-06-21

122

Acetone sensor based on zinc oxide hexagonal tubes  

NASA Astrophysics Data System (ADS)

In this work hexagonal tubes of zinc oxide have been synthesized by co-precipitation method. For structural, morphological, elemental and optical analysis synthesized powders were characterized by using x-ray diffraction, field emission scanning microscope, EDX, UV-visible and FTIR techniques. For acetone sensing thick films of zinc oxide have been deposited on alumina substrate. The fabricated sensors exhibited maximum sensing response towards acetone vapour at an optimum operating temperature of 400°C.

Hastir, Anita; Singh, Onkar; Anand, Kanika; Singh, Ravi Chand

2014-04-01

123

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

124

Direct synthesis of highly crystalline transparent conducting oxide nanoparticles by low pressure spray pyrolysis  

Microsoft Academic Search

In this article, we firstly reported a general preparation method for the production of highly crystallized and single crystalline transparent conducting oxide (TCO) nanoparticles: tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), aluminum-doped zinc oxide (AZO), and gallium-doped zinc oxide (GZO). Low-pressure spray pyrolysis was applied by means of a modified-atomizer and preheated carrier gas. The effects of pyrolysis pressure,

Takashi Ogi; Darmawan Hidayat; Ferry Iskandar; Agus Purwanto; Kikuo Okuyama

2009-01-01

125

Biomedical applications of zinc oxide nanomaterials.  

PubMed

Nanotechnology has witnessed tremendous advancement over the last several decades. Zinc oxide (ZnO), which can exhibit a wide variety of nanostructures, possesses unique semiconducting, optical, and piezoelectric properties hence has been investigated for a wide variety of applications. The most important features of ZnO nanomaterials are low toxicity and biodegradability. Zn(2+) is an indispensable trace element for adults (~10 mg of Zn(2+) per day is recommended) and it is involved in various aspects of metabolism. Chemically, the surface of ZnO is rich in -OH groups, which can be readily functionalized by various surface decorating molecules. In this review article, we summarized the current status of the use of ZnO nanomaterials for biomedical applications, such as biomedical imaging (which includes fluorescence, magnetic resonance, positron emission tomography, as well as dual-modality imaging), drug delivery, gene delivery, and biosensing of a wide array of molecules of interest. Research in biomedical applications of ZnO nanomaterials will continue to flourish over the next decade, and much research effort will be needed to develop biocompatible/biodegradable ZnO nanoplatforms for potential clinical translation. PMID:24206130

Zhang, Y; Nayak, T R; Hong, H; Cai, W

2013-12-01

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

Surface studies of zinc oxide growth on Cu(110)  

NASA Astrophysics Data System (ADS)

Submonolayers to multilayers of zinc and oxygen deposited in UHV on Cu(110) were characterized by Auger electron spectroscopy (AES), low energy electron diffraction (LEED), and temperature programmed desorption (TPD) of CO, CO 2 and zinc. Carbon monoxide adsorbs will on copper at 150 K but only poorly on the oxides of copper and zinc. Carbon dioxide adsorbs on zinc oxide at 150 K but not on copper or oxidized copper. We used a combination of CO and CO 2 adsorption to follow the initial growth of two-dimensional ZnO x islands and the effect of heat and oxygen treatments on these two-dimensional islands. It is shown that heating above 300 K leads irreversibly to three-dimensional islands formation.

Fu, Sabrina S.; Somorjai, Gabor A.

1990-11-01

128

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

129

Synthetic silver oxide and mercury-free zinc electrodes for silver-zinc reserve batteries  

NASA Astrophysics Data System (ADS)

Reserve activated silver oxide-zinc cells were constructed with synthetic silver oxide (Ag 2O) electrodes with Pb-treated zinc electrodes produced by a non-electrolytic process. The cells were tested before and after thermally accelerated aging. At discharge rates up to 80 mA cm -2, the discharge was limited by the Ag 2O electrode, with a coulombic efficiency between 89-99%. At higher rates, the cells are apparently zinc-limited. Test cells were artificially aged at 90°C for 19 h and discharged at 21°C at 80 mA cm -2. No capacity loss was measured, but a delayed activation rise time was noted (192 ms fresh vs. 567 ms aged). The delay is thought to be caused by zinc passivation due to the outgassing of cell materials.

Smith, David F.; Gucinski, James A.

130

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

2012-08-27

131

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

132

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

NASA Astrophysics Data System (ADS)

Zinc self-diffusion was measured in single crystal zinc oxide using nonradioactive 70Zn 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 pO2 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.

Tomlins, Gregory W.; Routbort, Jules L.; Mason, Thomas O.

2000-01-01

133

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.

134

Solvent free synthesis of chalcone and flavanone over zinc oxide supported metal oxide catalysts  

Microsoft Academic Search

Liquid phase Claisen–Schmidt condensation between 2?-hydroxyacetophenone and benzaldehyde to form 2?-hydroxychalcone, followed by intramolecular cyclisation to form flavanone was carried out over zinc oxide supported metal oxide catalysts under solvent free condition. The reaction was carried out over ZnO supported MgO, BaO, K2O and Na2O catalysts with 0.2g of each catalyst at 140°C for 3h. Magnesium oxide impregnated zinc oxide

S. Saravanamurugan; M. Palanichamy; Banumathi Arabindoo; V. Murugesan

2005-01-01

135

Leaching of oxidic zinc materials with chlorine and chlorine hydrate  

NASA Astrophysics Data System (ADS)

Low grade zinc ores and residues were leached in chlorine water and chlorine hydrate water mixtures. It was found that the rate of leaching Adrar ore and Electric Arc Furnace dust obeyed a shrinking core diffusion model, whereas, the rate of leaching of Turkish ore appeared to be controlled by a surface reaction. In all cases, lead leached with the zinc but the iron oxides remained virtually undissolved.

Thomas, B. K.; Fray, D. J.

1981-06-01

136

Lattice dynamical investigations on Zn diffusion in zinc oxide  

Microsoft Academic Search

Zinc self diffusion in bulk zinc oxide is studied by lattice dynamical approach here to get more insight into the diffusion\\u000a in nano ZnO. The results reveal that only cationic self diffusion is dominant over anionic self diffusion and that too by\\u000a single vacancy mechanism. The results are compared with the available experiments and discussed.

P VINOTHA BOORANA LAKSHMI; K RAMACHANDRAN

2011-01-01

137

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

138

Zinc hydroxyacetate and its transformation to nanocrystalline zinc oxide.  

PubMed

The synthesis of nanocrystalline ZnO by thermal decomposition of zinc hydroxyacetate, Zn(5)(OH)(8)(CH(3)CO(2))(2)·nH(2)O, was investigated. The decomposition process was examined using X-ray diffraction, thermogravimetric analysis, mass spectrometry, electron microscopy, Brunauer-Emmett-Teller surface area analysis, and solid-state NMR spectroscopy. Intermediate Zn(5)(OH)(8)(CH(3)CO(2))(2)·nH(2)O phases form at temperatures up to 110 °C from the starting compound Zn(5)(OH)(8)(CH(3)CO(2))(2)·2H(2)O by partial dehydration. At ?110 °C, 4 equiv of ZnO and 1 equiv of Zn(CH(3)CO(2))(2) are formed. Further heating causes Zn(CH(3)CO(2))(2) to decompose to acetone, acetic acid, acetic anhydride, and ZnO. Notably, a portion of Zn(CH(3)CO(2))(2) sublimes during the process. Overall, the product of the calcination is equiaxed ZnO nanocrystals of 20-100 nm diameter. PMID:23249099

Moezzi, Amir; McDonagh, Andrew; Dowd, Annette; Cortie, Michael

2013-01-01

139

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

140

Analysis of cellular responses of macrophages to zinc ions and zinc oxide nanoparticles: a combined targeted and proteomic approach  

NASA Astrophysics Data System (ADS)

Two different zinc oxide nanoparticles, as well as zinc ions, are used to study the cellular responses of the RAW 264 macrophage cell line. A proteomic screen is used to provide a wide view of the molecular effects of zinc, and the most prominent results are cross-validated by targeted studies. Furthermore, the alteration of important macrophage functions (e.g. phagocytosis) by zinc is also investigated. The intracellular dissolution/uptake of zinc is also studied to further characterize zinc toxicity. Zinc oxide nanoparticles dissolve readily in the cells, leading to high intracellular zinc concentrations, mostly as protein-bound zinc. The proteomic screen reveals a rather weak response in the oxidative stress response pathway, but a strong response both in the central metabolism and in the proteasomal protein degradation pathway. Targeted experiments confirm that carbohydrate catabolism and proteasome are critical determinants of sensitivity to zinc, which also induces DNA damage. Conversely, glutathione levels and phagocytosis appear unaffected at moderately toxic zinc concentrations.Two different zinc oxide nanoparticles, as well as zinc ions, are used to study the cellular responses of the RAW 264 macrophage cell line. A proteomic screen is used to provide a wide view of the molecular effects of zinc, and the most prominent results are cross-validated by targeted studies. Furthermore, the alteration of important macrophage functions (e.g. phagocytosis) by zinc is also investigated. The intracellular dissolution/uptake of zinc is also studied to further characterize zinc toxicity. Zinc oxide nanoparticles dissolve readily in the cells, leading to high intracellular zinc concentrations, mostly as protein-bound zinc. The proteomic screen reveals a rather weak response in the oxidative stress response pathway, but a strong response both in the central metabolism and in the proteasomal protein degradation pathway. Targeted experiments confirm that carbohydrate catabolism and proteasome are critical determinants of sensitivity to zinc, which also induces DNA damage. Conversely, glutathione levels and phagocytosis appear unaffected at moderately toxic zinc concentrations. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00319e

Triboulet, Sarah; Aude-Garcia, Catherine; Armand, Lucie; Gerdil, Adèle; Diemer, Hélène; Proamer, Fabienne; Collin-Faure, Véronique; Habert, Aurélie; Strub, Jean-Marc; Hanau, Daniel; Herlin, Nathalie; Carrière, Marie; van Dorsselaer, Alain; Rabilloud, Thierry

2014-05-01

141

Structure and stability of small zinc oxide clusters  

NASA Astrophysics Data System (ADS)

The structure and stability of small neutral and positively charged zinc oxide (ZnO) n clusters ( n = 2-9) have been studied within the density functional theory. For n ? 7, the most stable clusters are shown to be flat rings; for n = 8, 9, the clusters are mainly three-dimensional cage structures. The energies and main channels of fragmentation of the clusters have been determined. It has been found that the fragmentation of the charged clusters with n > 6 occurs predominantly with formation of a (ZnO){4/+} ion, which explains the available mass spectrometric data on ionization of the zinc oxide clusters by electron impact.

Trushin, E. V.; Zilberberg, I. L.; Bulgakov, A. V.

2012-04-01

142

Hydrogen Reduction of Zinc and Iron Oxides Containing Mixtures  

NASA Astrophysics Data System (ADS)

Zinc is a metal of significant technological importance and its production from secondary sources has motivated the development of alternative processes, such as the chemical treatment of electrical arc furnace (EAF) dust. Currently, the extraction of zinc from the mentioned residue using a carbon-containing reducing agent is in the process of being established commercially and technically. In the current study, the possibility of reducing zinc from an EAF dust sample through a H2 constant flux in a horizontal oven is studied. The reduction of a synthetic oxide mixture of analogous composition is also investigated. The results indicated that the reduction process is thermodynamically viable for temperatures higher than 1123 K (850 °C), and all zinc metal produced is transferred to the gas stream, enabling its complete separation from iron. The same reaction in the presence of zinc crystals was considered for synthesizing FeZn alloys. However, for the experimental conditions employed, although ZnO reduction was indeed thermodynamically hindered because of the presence of zinc crystals (the metal's partial pressure was enhanced), the zinc metal's escape within the gaseous phase could not be effectively avoided.

de Siqueira, Rogério Navarro C.; de Albuquerque Brocchi, Eduardo; de Oliveira, Pamela Fernandes; Motta, Marcelo Senna

2013-10-01

143

Thin zinc oxide and cuprous oxide films for photovoltaic applications  

NASA Astrophysics Data System (ADS)

Metal oxide semiconductors and heterojunctions made from thin films of metal oxide semiconductors have broad range of functional properties and high potential in optical, electrical and magnetic devices such as light emitting diodes, spintronic devices and solar cells. Among the oxide semiconductors, zinc oxide (ZnO) and cuprous oxide (Cu2O) are attractive because they are inexpensive, abundant and nontoxic. As synthesized ZnO is usually an intrinsic n - type semiconductor with wide band gap (3.4 eV) and can be used as the transparent conducting window layer in solar cells. As synthesized Cu2O is usually a p - type semiconductor with a band gap of 2.17 eV and has been considered as a potential material for the light absorbing layer in solar cells. I used various techniques including metal organic chemical vapor deposition, magnetron sputtering and atomic layer deposition to grow thin films of ZnO and Cu2O and fabricated Cu2O/ZnO heterojunctions. I specifically investigated the optical and electrical properties of Cu 2O thin films deposited on ZnO by MOCVD and showed that Cu2O thin films grow as single phase with [110] axis aligned perpendicular to the ZnO surface which is (0001) plane and with in-plane rotational alignment due to (220) Cu2O || (0002)ZnO; [001]Cu2O || [12¯10]ZnO epitaxy. Moreover, I fabricated solar cells based on these Cu2O/ZnO heterojunctions and characterized them. Electrical characterization of these solar cells as a function of temperature between 100 K and 300 K under illumination revealed that interface recombination and tunneling at the interface are the factors that limit the solar cell performance. To date solar cells based on Cu2O/ZnO heterojunctions had low open circuit voltages (~ 0.3V) even though the expected value is around 1V. I achieved open circuit voltages approaching 1V at low temperature (~ 100 K) and showed that if interfacial recombination is reduced these cells can achieve their predicted potential.

Jeong, Seongho

144

Paracetamol inhibits copper ion-induced, azo compound-initiated, and mononuclear cell-mediated oxidative modification of LDL.  

PubMed

The effects of paracetamol and sodium salicylate on the susceptibility of LDL to oxidative modification were studied. LDL was subjected to Cu(2+)-, azo compound-, or peripheral blood mononuclear cell-initiated oxidation in the absence and presence of paracetamol and salicylate. Paracetamol (100 mumol/L; 25 micrograms LDL/mL) reduced the rate of formation of conjugated dienes and the amount of conjugated dienes formed during Cu(2+)-induced oxidation by 67% and 58%, respectively. Paracetamol (400 mumol/L; 100 micrograms LDL/mL) reduced the generation of lipid peroxides during Cu(2+)-induced oxidation by 43% (P < .05), the relative electrophoretic mobility in agarose gels by 16% (P < .05), and the amount of oxidized LDL taken up by J774 macrophages by 22% (P < .05). Paracetamol (100 mumol/L; 100 micrograms LDL/mL) reduced the 2,2'-azobis-(2-amidinopropane hydrochloride)-initiated lipid peroxidation by 70% (P < .05) and the relative electrophoretic mobility by 34% (P < .05). Paracetamol (100 mumol/L; 100 micrograms LDL/mL) reduced the amount of lipid peroxides generated in LDL during mononuclear cell-mediated oxidation by 69% (P < .01) and the relative electrophoretic mobility by 38% (P < .01). In comparison, 10 mumol/L alpha-tocopherol reduced the amount of lipid peroxides formed during cellular LDL oxidation and the relative electrophoretic mobility by 52% and 65%, respectively (P < .05). In the absence of paracetamol, SOD and catalase inhibited the modification of LDL (P < .05), suggesting that superoxide anions and hydrogen peroxide might be involved in the cell-mediated modification pathway. In the presence of paracetamol, SOD showed no additional inhibitory effect.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7670947

Nenseter, M S; Halvorsen, B; Rosvold, O; Rustan, A C; Drevon, C A

1995-09-01

145

Oxidation potentials in lead and zinc smelting  

NASA Astrophysics Data System (ADS)

Oxygen sensors based on the solid electrolyte ZrO2 found early and enthusiastic acceptance in the iron, steel, and copper smelting industries. Their adoption for lead and zinc smelting processes has been slower. This paper reviews the general principles of this technology, discusses its application, and suggests what might be expected in its expanded use.

Matousek, Jan W.

2011-12-01

146

Volatile organic compound gas sensor based on aluminum-doped zinc oxide with nanoparticle.  

PubMed

Thick film semiconductor gas sensors based on aluminum-doped zinc oxide (AZO) with nanoparticle size were fabricated to detect volatile organic compound (VOC) existed in building, especially, formaldehyde (HCHO) gas which was known as the cause of sick building syndrome. The sensing materials for screen printing were prepared using roll milling process with binder. The crystallite sizes of prepared materials were about 15 nm through X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). Gas response characteristics were examined for formaldehyde (HCHO), benzene, carbon monoxide, carbon dioxide gas existing in building. In particular, the sensors showed responses to HCHO gas at sub ppm as a function of operating temperatures and gas concentrations. Also, we investigated sensitivity, repeativity, selectivity, and response time of sensor. The transients were very sharp, taking less than 2 s for 90% response. The sensor has shown very stable response at 350 degrees C and followed a very good behavior and showed 60% response in 50 ppb HCHO concentration at 350 degrees C operating temperatures. PMID:23882782

Choi, Nak-Jin; Lee, Hyung-Kun; Moon, Seung Eon; Yang, Woo Seok; Kim, Jongdae

2013-08-01

147

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

148

Various Ways to Reduce Zinc Oxide Levels in S-SBR Rubber Compounds  

Microsoft Academic Search

Because of environmental concerns, the zinc content in rubber compounds has come under scrutiny. The research described in this article encompasses zinc-oxide, various zinc-complexes and alternative metal oxides as activators for sulphur vulcanisation. Regarding zinc complexes, it can be concluded that zinc- m-glycerolate is a good substitute for ZnO as activator for sulphur vulcanisation in s-SBR rubber, without detrimental effects

Geert Heideman; Jacques W. M. Noordermeer; Rabin N. Datta; Baarle van Ben

2006-01-01

149

Relative yield and zinc uptake by rice from zinc sulphate and zinc oxide coatings onto urea  

Microsoft Academic Search

Zinc (Zn) deficiency is prevalent worldwide and is a barrier to achieving yield goals in crops. It is also now recognized\\u000a as a leading risk factor for disease in humans in developing countries. In general, soil application of 5–17 kg of Zn ha?1 year?1 as zinc sulphate (ZnSO4) or more is recommended. However, in developing rice growing countries of Asia, ZnSO4 of

Yashbir Singh Shivay; Dinesh Kumar; Rajendra Prasad; I. P. S. Ahlawat

2008-01-01

150

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

151

Resputtering of zinc oxide films prepared by radical assisted sputtering  

SciTech Connect

Sputtering losses of zinc oxide films prepared by radical assisted sputtering were studied. It was found that the sputtering loss can be very severe in oxygenous sputtering processes of zinc oxide films. In general, resputtering caused by negative oxygen ions dominates the sputtering loss, while diffuse deposition plays a minor role. Resputtering is strongly correlated with the sputtering threshold energy of the deposited films and the concentration of O{sup -} in the sputtering zone. The balance between the oxygen concentration in the sputtering zone and the oxidation degree of the growing films depends on the sputtering rate. Our research suggests that a lower oxygen concentration in the sputtering zone and a higher oxidation degree of the growing films are favorable for reducing the resputtering losses. The sputtering loss mechanisms discussed in this work are also helpful for understanding the deposition processes of other magnetron sputtering systems.

Song Qiuming [Hefei National Laboratory for Physical Science at Microscale and USTC-SHINCRON Joint Laboratory, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); CAS/CUHK Shenzhen Institute of Advanced Integration Technology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518054 (China); Wu Bingjun; Xie Bin; Huang Feng; Li Ming; Wang Haiqian [Hefei National Laboratory for Physical Science at Microscale and USTC-SHINCRON Joint Laboratory, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); Jiang Yousong; Song Yizhou [Shincron Co., LTD., Shinagawa-Ku, Tokyo 140-0011 (Japan)

2009-02-15

152

Spray pyrolysis deposition of cadmium–zinc oxide thin films  

Microsoft Academic Search

Mixed thin film oxides of cadmium and zinc with different compositions were deposited on glass substrates by spray pyrolysis. The effect of the various parameters on the growth and on the film properties is presented. The sample structure was studied by X-ray diffraction (XRD) having found the presence of a cubic phase resembling that of pure CdO XRD pattern for

O. Vigil; L Vaillant; F Cruz; G Santana; A Morales-Acevedo; G Contreras-Puente

2000-01-01

153

Potassium silicate-zinc oxide solution for metal finishes  

NASA Technical Reports Server (NTRS)

Examples of zinc dust formulations, which are not subject to cracking or crazing, are fire retardant, and have high adhesive qualities, are listed. The potassium silicate in these formulations has mol ratios of dissolved silica potassium oxide in the range 4.8 to 1 - 5.3 to 1.

Schutt, J. B.

1970-01-01

154

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

155

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

156

Process for fabricating doped zinc oxide microsphere gel  

DOEpatents

Disclosed are 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.

1991-11-05

157

Synthesis and local structure of doped nanocrystalline zinc oxides  

NASA Astrophysics Data System (ADS)

Nanocrystalline zinc oxides are produced by chemical vapor synthesis and characterized by x-ray diffraction, high resolution transmission electron microscopy, nitrogen sorption, and extended x-ray absorption fine structure. Dopant elements (aluminum, gallium, and indium) influence the particle size of the powders as well as lattice parameters and local structure. The different effects of the three dopant elements are characterized.

Brehm, Joachim U.; Winterer, Markus; Hahn, Horst

2006-09-01

158

Chemical vapor deposition of fluorine-doped zinc oxide  

DOEpatents

Fims of fluorine-doped zinc oxide are deposited from vaporized precursor compounds comprising a chelate of a dialkylzinc, such as an amine chelate, an oxygen source, and a fluorine source. The coatings are highly electrically conductive, transparent to visible light, reflective to infrared radiation, absorbing to ultraviolet light, and free of carbon impurity.

Gordon, Roy G. (Cambridge, MA); Kramer, Keith (Avon Lake, OH); Liang, Haifan (Santa Clara, CA)

2000-06-06

159

Analysis of cellular responses of macrophages to zinc ions and zinc oxide nanoparticles: a combined targeted and proteomic approach.  

PubMed

Two different zinc oxide nanoparticles, as well as zinc ions, are used to study the cellular responses of the RAW 264 macrophage cell line. A proteomic screen is used to provide a wide view of the molecular effects of zinc, and the most prominent results are cross-validated by targeted studies. Furthermore, the alteration of important macrophage functions (e.g. phagocytosis) by zinc is also investigated. The intracellular dissolution/uptake of zinc is also studied to further characterize zinc toxicity. Zinc oxide nanoparticles dissolve readily in the cells, leading to high intracellular zinc concentrations, mostly as protein-bound zinc. The proteomic screen reveals a rather weak response in the oxidative stress response pathway, but a strong response both in the central metabolism and in the proteasomal protein degradation pathway. Targeted experiments confirm that carbohydrate catabolism and proteasome are critical determinants of sensitivity to zinc, which also induces DNA damage. Conversely, glutathione levels and phagocytosis appear unaffected at moderately toxic zinc concentrations. PMID:24788578

Triboulet, Sarah; Aude-Garcia, Catherine; Armand, Lucie; Gerdil, Adèle; Diemer, Hélène; Proamer, Fabienne; Collin-Faure, Véronique; Habert, Aurélie; Strub, Jean-Marc; Hanau, Daniel; Herlin, Nathalie; Carrière, Marie; Van Dorsselaer, Alain; Rabilloud, Thierry

2014-06-01

160

Kinetics of the dissolution of zinc sulfide in an oxidizing slag  

NASA Astrophysics Data System (ADS)

A new concept has been developed for the production of zinc from zinc and complex zinc concentrates. It is a two-stage process involving oxidation of zinc sulfide to oxide and dissolution into slag and the fuming of zinc from the slag by injecting carbonaceous materials into it to produce zinc vapors which can be subsequently condensed in a lead-splash condenser such as those used in the Imperial Smelting Process (ISP). In this paper, the effects of the quantity of air, temperature, and concentrate feed rate have been discussed on the production of zinc-rich slag, which is the first stage of the proposed process.

Gupta, Suresh K.

1990-10-01

161

Biodecolorization of azo dye Remazol orange by Pseudomonas aeruginosa BCH and toxicity (oxidative stress) reduction in Allium cepa root cells.  

PubMed

In this report a textile azo dye Remazol orange was degraded and detoxified by bacterium Pseudomonas aeruginosa BCH in plain distilled water. This bacterial decolorization performance was found to be pH and temperature dependent with maximum decolorization observed at pH 8 and temperature 30 °C. Bacterium tolerated higher dye concentrations up to 400 mg?l(-1). Effect of initial cell mass showed that higher cell mass concentration can accelerate decolorization process with maximum of 92 % decolorization observed at 2.5 g?l(-1) cell mass within 6.5 h. Effect of various metal ions showed Mn has inducing effect whereas Zn strongly inhibited the decolorization process at 5 mM concentration. Analysis of biodegradation products carried out with UV-vis spectroscopy, HPTLC and FTIR confirmed the decolorization and degradation of Remazol orange. Possible route for the degradation of dye was proposed based on GC-MS analysis. During toxicological scrutiny in Allium cepa root cells, induction in the activities of superoxide dismutase (SOD), guaiacol peroxidase (GPX) and inhibition of catalase (CAT) along with raised levels of lipid peroxidation and protein oxidation in dye treated samples were detected which conclusively indicated the generation of oxidative stress. Less toxic nature of the dye degraded products was observed after bacterial treatment. PMID:22948606

Jadhav, Shekhar B; Surwase, Shripad N; Kalyani, Dayanand C; Gurav, Ranjit G; Jadhav, Jyoti P

2012-11-01

162

A statistical experiment design approach for advanced oxidation of Direct Red azo-dye by photo-Fenton treatment.  

PubMed

Advanced oxidation of an azo-dye, Direct Red 28 (DR 28) by photo-Fenton treatment was investigated in batch experiments using Box-Behnken statistical experiment design and the response surface analysis. Dyestuff (DR 28), H(2)O(2) and Fe(II) concentrations were selected as independent variables in Box-Behnken design while color and total organic carbon (TOC) removal (mineralization) were considered as the response functions. Color removal increased with increasing H(2)O(2) and Fe(II) concentrations up to a certain level. High concentrations of H(2)O(2) and Fe(II) adversely affected the color and TOC removals due to hydroxyl radical scavenging effects of high oxidant and catalyst concentrations. Both H(2)O(2) and Fe(II) concentration had profound effects on decolorization. Percent color removal was higher than TOC removal indicating formation of colorless organic intermediates. Complete color removal was achieved within 5min while complete mineralization took nearly 15min. The optimal reagent doses varied depending on the initial dyestuff dose. For the highest dyestuff concentration tested, the optimal H(2)O(2)/Fe(II)/dyestuff ratio resulting in the maximum color removal (100%) was predicted to be 715/71/250 (mgL(-1)), while this ratio was 1550/96.5/250 for maximum mineralization (97.5%). PMID:18555599

Ay, Filiz; Catalkaya, Ebru Cokay; Kargi, Fikret

2009-02-15

163

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) [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)] [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)] [Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States)

2000-01-01

164

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

165

Sulfidation and reduction of zinc titanate and zinc oxide sorbents for injection in gasifier exit ducts  

SciTech Connect

The sulfidation reaction kinetics of fine particles of zinc titanate and zinc oxide with H{sub 2}S were studied in order to test the potential of the sorbent injection hot-gas desulfurization process. Fine sorbent particles with diameter between 0.3 and 60 {mu}m were sulfided with H{sub 2}S and/or reduced with H{sub 2} in a laminar flow reactor over the temperature range of 500-900{degrees}C. Sulfidation/reduction conversion was compared for different particle sizes and sorbents with various porosities and atomic ratios of Zn and Ti. In reduction of ZnO with H{sub 2} and without H{sub 2}S, significant amount of Zn was formed and vaporized, while the presence of H{sub 2}S suppressed elemental Zn formation. This suggests that H{sub 2}S may suppress the surface reduction of ZnO and/or gaseous Zn may react with H{sub 2}S homogeneously and form fine particles of ZnS. Formation and vaporization of elemental Zn from zinc titanate sorbents was slower than from zinc oxide with and without H{sub 2}S.

Ishikawa, K. [Tufts Univ., Medford, MA (United States). Dept. of Chemical Engineering]|[Kawasaki Heavy Industries Ltd., Akashi, Hyogo (Japan). Technical Inst.; Krueger, C.; Flytzani-Stephanopoulos, M. [Tufts Univ., Medford, MA (United States). Dept. of Chemical Engineering; Jl, W.; Higgins, R.J.; Bishop, B.A.; Goldsmith, R.L. [CeraMem Corp., Waltham, MA (United States)

1995-12-31

166

Zinc oxide's hierarchical nanostructure and its photocatalytic properties  

NASA Astrophysics Data System (ADS)

In this study, a new hierarchical nanostructure that consists of zinc oxide (ZnO) was produced by the electrospinning process followed by a hydrothermal technique. First, electrospinning of a colloidal solution that consisted of zinc nanoparticles, zinc acetate dihydrate and poly(vinyl alcohol) was performed to produce polymeric nanofibers embedding solid nanoparticles. Calcination of the obtained electrospun nanofiber mats in air at 500 °C for 90 min produced pure ZnO nanofibers with rough surfaces. The rough surface strongly enhanced outgrowing of ZnO nanobranches when a specific hydrothermal technique was used. Methylene blue dihydrate was used to check the photocatalytic ability of the produced nanostructures. The results indicated that the hierarchical nanostructure had a better performance than the other form.

Kanjwal, Muzafar A.; Sheikh, Faheem A.; Barakat, Nasser A. M.; Li, Xiaoqiang; Kim, Hak Yong; Chronakis, Ioannis S.

2012-02-01

167

Green synthesis of zinc oxide nanoparticles by aloe barbadensis miller leaf extract: Structure and optical properties  

Microsoft Academic Search

Biological methods for nanoparticle synthesis using microorganisms, enzymes, and plants or plant extracts have been suggested as possible ecofriendly alternatives to chemical and physical methods. In this paper, we report on the synthesis of nanostructured zinc oxide particles by both chemical and biological method. Highly stable and spherical zinc oxide nanoparticles are produced by using zinc nitrate and Aloe vera

Gunalan Sangeetha; Sivaraj Rajeshwari; Rajendran Venckatesh

2011-01-01

168

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

169

40 CFR 721.2577 - Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine...  

Code of Federal Regulations, 2010 CFR

...substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine...substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine...substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl...

2009-07-01

170

Zinc coatings for oxidation protection of ferrous substrates  

Microsoft Academic Search

A common phenomenon in the process industries is the oxidation of the exterior surface of steel pipes used in superheated\\u000a steam or hot oils networks. For their protection different coatings could be used. In the present work the performance of\\u000a zinc coatings deposited with hot-dip galvanizing, pack cementation and thermal spraying was considered, in order to protect\\u000a industrial equipment up

G. Vourlias; N. Pistofidis; E. Pavlidou; K. Chrissafis

2007-01-01

171

Growth and process induced dislocations in zinc oxide crystals  

NASA Astrophysics Data System (ADS)

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.

2006-12-01

172

A new method for preparation of zinc oxide whiskers  

Microsoft Academic Search

Tetrapod-shaped ZnO whiskers were prepared with high yield and good purity in a short reaction time by a new method, the oxidation of pellets or otherwise shaped metallic zinc at 500–800°C under atmospheric pressure. The reaction conditions were analyzed and compared with other methods. The products were identified by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The results

Zuowan Zhou; Hai Deng; Jing Yi; Shikai Liu

1999-01-01

173

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

174

Bulk Zinc Oxide and Gallium Nitride Crystals by Solvothermal Techniques  

Microsoft Academic Search

We report on recent achievements from the growth of hydrothermal zinc oxide (ZnO) and ammonothermal gallium nitride (GaN).\\u000a A thin-film deposition technique under conditions near the thermodynamic equilibrium, liquid phase epitaxy (LPE) is applied\\u000a for fast screening of dopants and their effects on physical properties of ZnO. In particular, super fast luminescent decay\\u000a will be reported from some donor-acceptor co-doped

D. Ehrentraut; T. Fukuda

175

Surface textured molybdenum zinc oxide for light diffusion enhancement  

Microsoft Academic Search

Surface textures have been fabricated on a molybdenum doped zinc oxide (MZO) film using a shadow mask in a co-sputter process. The surface textures yielded 5.3% and 10.1% of light diffusion in the visible light region for MZO films with a thickness of 100 nm and 200 nm, respectively. Light diffusion in the near infra-red region was slightly less with 4.5% for

Ching-Ming Hsu; Hon-Bin Lin; Wen-Tuan Wu

2009-01-01

176

Electrical and optical properties of zinc oxide for scintillator applications  

Microsoft Academic Search

Zinc oxide (ZnO) is a wide-band-gap semiconductor suitable for many optical and optoelectronic applications. Among these is to use single crystal, powder, or ceramic forms of ZnO as a fast UV scintillator. In this work, the electrical and optical properties of ZnO were studied using photoluminescence, X-ray-induced luminescence, optical absorption, and Hall Effect techniques. This study included single crystal ZnO

Xiaocheng Yang

2008-01-01

177

Controlled Co(II) Doping of Zinc Oxide Nanocrystals  

Microsoft Academic Search

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

S Bohle; C Spina

2011-01-01

178

Zinc oxide nanoparticle and polymer antimicrobial biomaterial composites  

Microsoft Academic Search

Particulate zinc oxide (ZnO) is a known antibacterial agent. Studies show that reducing the size of ZnO particles to nanoscale dimensions further enhances their antibacterial properties. Polymers, like all biomaterials, run the risk of harboring bacteria which may produce an antibiotic-resistant biofilm. The addition of ZnO nanoparticles, to form a composite, may reduce undesirable bacteria activity. The purpose of the

Justin T. Seil; Thomas J. Webster

2010-01-01

179

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

180

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

181

Influence of doping with third group oxides on properties of zinc oxide thin films  

SciTech Connect

The study of modifications in structural, optical and electrical properties of vacuum evaporated zinc oxide thin films on doping with III group oxides namely aluminum oxide, gallium oxide and indium oxide are reported. It was observed that all the films have transmittance ranging from 85 to 95%. The variation in optical properties with dopants is discussed. On doping the film with III group oxides, the conductivity of the films showed an excellent improvement of the order of 10{sup 3} {Omega}{sup -1} cm{sup -1}. The measurements of activation energy showed that all three oxide doped films have 2 donor levels below the conduction band.

Palimar, Sowmya, E-mail: sowmya0124@gmail.com; Bangera, Kasturi V.; Shivakumar, G. K. [National Institute of Technology Karnataka, Thin Film Laboratory, Physics Department (India)

2013-03-15

182

Superior antibacterial activity of zinc oxide/graphene oxide composites originating from high zinc concentration localized around bacteria.  

PubMed

New materials with good antibacterial activity and less toxicity to other species attract numerous research interest. Taking advantage of zinc oxide (ZnO) and graphene oxide (GO), the ZnO/GO composites were prepared by a facile one-pot reaction to achieve superior antibacterial properties without damaging other species. In the composites, ZnO nanoparticles (NPs), with a size of about 4 nm, homogeneously anchored onto GO sheets. The typical bacterium Escherichia coli and HeLa cell were used to evaluate the antibacterial activity and cytotoxicity of the ZnO/GO composites, respectively. The synergistic effects of GO and ZnO NPs led to the superior antibacterial activity of the composites. GO helped the dispersion of ZnO NPs, slowed the dissolution of ZnO, acted as the storage site for the dissolved zinc ions, and enabled the intimate contact of E. coli with ZnO NPs and zinc ions as well. The close contact enhanced the local zinc concentration pitting on the bacterial membrane and the permeability of the bacterial membrane and thus induced bacterial death. In addition, the ZnO/GO composites were found to be much less toxic to HeLa cells, compared to the equivalent concentration of ZnO NPs in the composites. The results indicate that the ZnO/GO composites are promising disinfection materials to be used in surface coatings on various substrates to effectively inhibit bacterial growth, propagation, and survival in medical devices. PMID:24495147

Wang, Yan-Wen; Cao, Aoneng; Jiang, Yu; Zhang, Xin; Liu, Jia-Hui; Liu, Yuanfang; Wang, Haifang

2014-02-26

183

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

184

Oxidative dehydrogenation of butenes over zinc ferrite catalysts  

SciTech Connect

The oxidative dehydrogenation (OXD) of butene over a zinc ferrite catalyst was studied in a batch recirculation and microcatalytic pulse reactor system at temperatures between 300 and 400/sup 0/C. Mechanistic features of the reaction were examined using deuterium-labeled butene and /sup 18/O-labeled carbon dioxide experiments. Solid-state changes in the catalyst were examined through x-ray powder diffraction and Moessbauer spectroscopy. Reaction products consist of 1,3-butadiene, carbon dioxide, water, and butene isomers. Kinetic expressions were constructed for both OXD and deep oxidation reactions based on a two site Langmuir-Hinshelwood model assuming dissociative adsorption for oxygen on one site and competitive adsorption by butene and butadiene on the other. The OXD of perdeuterated butene is slower than that of undeuterated butene, which indicates a significant kinetic isotope effect of 2.7 at 350/sup 0/C. A similar effect was observed for isomerization of cis-2-butene to 1-butene by double bond shift (1.4 at 350/sup 0/C). Apparently, carbon-hydrogen bond cleavage is involved in the rate limiting step for both reactions. Microcatalytic pulse experiments carried out in the absence of gas phase oxygen indicated that the lattice oxygen does not participate in the reaction and that the migration of bulk oxygen to the surface of the catalyst is very slow under these conditions. A similar results was observed in /sup 18/O exchange experiments with C/sup 18/O/sub 2/. The experimental data are consistent with an oxidation-reduction cycle involving Fe/sup +2//Fe/sup +3/ interconversion. Increased catalytic activity at higher temperatures is believed to be due to an enhancement of catalytic activity by iron oxides formed by the decomposition of zinc ferrite into zinc oxide and iron oxide.

Park, T.J.

1987-01-01

185

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

186

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

187

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

188

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

NASA Astrophysics Data System (ADS)

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. Modulation doping was chosen as a possible technique to achieve this outcome. ZnMgO:Al films were grown and characterized as a potential barrier layer in a modulation doped structure. High quality films, rocking curve FWHM ˜1-2°, were grown on c-plane sapphire substrates. The ability of Mg to increase the band gap of ZnO up to a value of 3.76 eV was confirmed. Aluminum was used as a donor in ZnMgO, and maximum carrier concentration levels of ˜1 x 1020 cm-3 were achieved. The wide band gap semiconductor ZnMgO:Al was determined to be a suitable choice as a barrier layer in a modulation doped structure. A one dimensional Schrodinger/Poisson simulation program was used to investigate the influence of the parameters in a modulation doped ZnO/ZnMgO:Al structure on the film properties. The optimum electrical properties were achieved when the active ZnO layer and barrier ZnMgO:Al layer were both in the range of 2-5 nm. The optimum thickness for the ZnMgO spacer layer was calculated to be 1.5 nm. Mobilities as high as 145 cm2/Vs were predicted for the optimum structures, compared to ˜30 cm2/Vs in monolithic ZnO films. The maximum sheet electron density that could be transferred from the doped to the undoped layers was predicted to be ˜10 13 cm-2. Multilayer structures were grown and characterized. Following the trends predicted from the multilayer simulations, a five period multilayer with ZnO and ZnMgO:Al layers of 5 nm had a mobility of ˜33 cm2/Vs and a resistivity of 1.44 x 10-3 O cm, compared to a multilayer with 20 nm thick layers which had a mobility of ˜23 cm 2/Vs and a resistivity of 2.45 x 10-3 O cm. The experimental results were in reasonable agreement with the predictions of the above simulation.

Cohen, David J.

189

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

190

Growth and characterization of transparent conducting nanostructured zinc indium oxide thin films  

Microsoft Academic Search

Transparent conductive oxide (TCO) films have been widely used in various applications, such as for transparent electrodes in flat-panel displays, and in solar cells, optoelectronic devices, touch panels and IR reflectors. Among these, tin doped zinc oxide (ZTO) and indium doped zinc oxide (ZIO) have attracted considerable attention. Particularly, IZO thin film is the best candidate for high-quality transparent conducting

Vipin Kumar Jain; Praveen Kumar; Deepika Bhandari; Y. K. Vijay

2010-01-01

191

Coating zinc oxide submicron crystals on poly(methyl methacrylate) chips and spheres via ultrasound irradiation  

Microsoft Academic Search

Ultrasound irradiation is used for anchoring zinc oxide submicron crystals with a main diameter and length of ?280nm and 470nm, respectively, onto the surface of poly(methyl methacrylate) PMMA chips (2mm diameter), and zinc oxide crystals with a mean diameter and length of ?150nm and 230nm, respectively, onto the surface of the PMMA spheres (1–10?m). The zinc oxide crystals were obtained

Kotlyar Anna; Perkas Nina; Koltypin Yuri; Meyer Meinhard; Zimmermann Werner; Gedanken Aharon

2008-01-01

192

Mechanism of methanol synthesis on copper\\/zinc oxide\\/alumina catalysts  

Microsoft Academic Search

This paper deals with the adsorption and temperature-programmed reaction spectroscopy of (i) formaldehyde on polycrystalline copper, polycrystalline zinc oxide and (ii) methanol on a copper\\/zinc oxide\\/alumina (60:30:10) catalyst. It shows that the energetics of formate hydrogenation\\/hydrogenolysis on the copper component of the catalyst, which is the rate-determining step in methanol synthesis on the copper\\/zinc oxide\\/alumina catalyst, is unaffected by the

M. Bowker; R. A. Hadden; H. Houghton; J. N. K. Hyland; K. C. Waugh

1988-01-01

193

Influences of Urea on Preparation of Zinc Oxide Nanostructures through Chemical Precipitation in Ammonium Hydrogencarbonate Solution  

Microsoft Academic Search

Zinc oxide nanostructures have been successfully prepared through dissolving of micro-sized zinc oxide powder in ammonium hydrogencarbonate solution at 25 ºC, followed by calcination of the resultant precipitates at 350 ºC for 1h. The influence of urea presence on morphology and particle size of the as-prepared zinc oxide was also investigated. The obtained products were characterized by XRD, SEM, FT-IR,

Zahra Monsef Khoshhesab; Mohammad Sarfaraz; Zari Houshyar

2012-01-01

194

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

195

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

196

Synthesis, characterization and optical properties of zinc oxide nanoparticles  

NASA Astrophysics Data System (ADS)

Zinc oxide nanoparticles were synthesized using a simple precipitation method with zinc sulfate and sodium hydroxide as starting materials. The synthesized sample was calcined at different temperatures for 2 h. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and proton-induced X-ray emission (PIXE) analysis. SEM images show various morphological changes of ZnO obtained by the above method. The average crystallite sizes of the samples were calculated from the full width at half maximum of XRD peaks by using Debye-Scherrer's formula and were found to be in the nanorange. EDS shows that the above route produced highly pure ZnO nanostructures. PIXE technique was used for trace elemental analysis of ZnO. The optical band gaps of various ZnO powders were calculated from UV-visible diffuse reflectance spectroscopic studies.

Kumar, Surabhi Siva; Venkateswarlu, Putcha; Rao, Vanka Ranga; Rao, Gollapalli Nagewsara

2013-05-01

197

Zinc protects against oxidative damage in cultured human retinal pigment epithelial cells  

Microsoft Academic Search

This study was undertaken to determine whether bioavailable zinc can influence the effects of oxidative stress on cultured human retinal pigment epithelial (RPE) cells. RPE cells were maintained for 7 d in culture medium containing 14 ?M total zinc, or in medium containing 0.55 ?M total zinc. After 1 week, MTT assays were performed to determine the relative cytotoxicity of

David J Tate; Michael V Miceli; David A Newsome

1999-01-01

198

Acceleration of zinc corrosion in alkaline suspensions containing iron oxides or iron hydroxides  

Microsoft Academic Search

Fast zinc dissolution is of industrial interest in recycling galvanised steel scraps. An acceleration of zinc corrosion in alkaline solutions was observed in the presence of various iron oxides or iron hydroxides. This corrosion was investigated by weight loss, measurements of hydrogen evolution and variation of current in a galvanic cell. The mechanism of this fast zinc corrosion was investigated

V. Alonzo; A. Darchen; D. Hauchard; S. Paofai

2003-01-01

199

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

PubMed Central

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.

2012-01-01

200

Enhancing the electrochemical oxidation of acid-yellow 36 azo dye using boron-doped diamond electrodes by addition of ferrous ion.  

PubMed

This work shows preliminary results on the electrochemical oxidation process (EOP) using boron-doped diamond (BDD) electrode for acidic yellow 36 oxidation, a common azo dye used in textile industry. The study is centred in the synergetic effect of ferrous ions and hydroxyl free radicals for improving discoloration of azo dye. The assays were carried out in a typical glass cell under potentiostatic conditions. On experimental conditions, the EOP was able to partially remove the dye from the reaction mixture. The reaction rate increased significantly by addition of Fe(2+) (1mM as ferrous sulphate) to the system and by (assumed) generation of ferrate ion [Fe(VI)] over BDD electrode. Ferrate is considered as a highly oxidizing reagent capable of removing the colorant from the reaction mixture, in synergistic action with the hydroxyl radicals produced on the BDD surface. Further increases in the Fe(2+) concentration lead to depletion of the reaction rate probably due to the hydroxyl radical scavenging effect of Fe(2+) excess in the system. PMID:19195775

Villanueva-Rodríguez, M; Hernández-Ramírez, A; Peralta-Hernández, J M; Bandala, Erick R; Quiroz-Alfaro, Marco A

2009-08-15

201

Calcium and zinc ion release from polyalkenoate cements formed from zinc oxide/apatite mixtures.  

PubMed

Calcium and zinc ion release from hydroxyapatite-zinc oxide-poly(acrylic acid) (HAZnO-PAA) composite cements into deionised water was investigated as a function of HA content, PAA concentration, PAA molecular weight and maturation time. At any given maturation time, zinc ion release was constant until the HA content was at the maximum loading (60 wt%) resulting in the cement matrix breaking up, allowing exacerbated ion release. The calcium ion release increased with increased HA content in the composite until the maximum loading where the release drops off. Up to this point, the release of both ionic species was proportional to square root time for the initial 24 hour period, indicating that the release is diffusion controlled. In agreement with related data from conventional Glass Polyalkenoate Cements (GPCs), it is the concentration of the PAA, not the molecular weight, that influences ion release from these materials. However, unlike GPCs, the release of the active ions results in a pH rise in the deionised water, more conventionally seen with Bioglass and related bioactive glasses. It is this pH rise, caused by the ion exchange of Zn(2+) and Ca(2+) for H(+) from the water, leaving an excess of OH(-), that should result in a favourable bioactive response both in vitro and in-vivo. PMID:16932866

Towler, M R; Kenny, S; Boyd, D; Pembroke, T; Buggy, M; Guida, A; Hill, R G

2006-09-01

202

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

203

Oxidative Modification of Guanine Bases Initiated by Oxyl Radicals Derived From Photolysis of Azo Compounds  

PubMed Central

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 (O2•?) 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 with observable rates with dG. The O2•? 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 combination of the G(-H)• and O2•? 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) 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.

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

2010-01-01

204

Efficient azo dye degradation by hydrogen peroxide oxidation with metalloporphyrins as catalysts  

Microsoft Academic Search

Degradation of organic dyes is a matter of great environmental concern. Despite many significant efforts and the numerous systems, which have been exploited, the problem is still unsolved due to intrinsically low activity or use of non-convenient chemical reagents. In this work, we describe the use of an oxidative system based on hydrogen peroxide activated by metalloporphyrins as catalysts to

Arménio C. Serra; Cristina Docal; A. M. d’A. Rocha Gonsalves

2005-01-01

205

The synthesis and optical properties of different zinc oxide nanostructures  

NASA Astrophysics Data System (ADS)

The tetrapod-like whiskers (T-ZnO), nanoaeroplanes, nanocombs, nanobelts, bead-like nanoforms and many other forms of hexagonal zinc oxide were synthesized by the chemical deposition process (CVD). From the experimental results it can be seen that the composition of source gases and the speed of oxidation are essential to the growth of each of these morphologies of zinc oxide. By controlling the growth conditions, one novel morphology of ZnO (bead-like nanoform) has been obtained. The ZnO tetrapod-like whiskers were grown without catalysts on the walls of quartz tube. The structure and morphology of the T-ZnO was characterized. All four legs of as-grown ZnO nanotetrapods are needle-like and hexagonal shaped and grow in the ±[0001] direction. The effect of synthesis conditions on the morphology and size T-ZnO was observed. Possible mechanisms of growth were investigated. The lengths of the legs of the tetrapods range from 1 to 15 ?m and diameter varying from 0.03 to 1 ?m during the synthesis. In the photoluminescence spectra T-ZnO clearly shows two maxima at UV and visible regions. The oxygen impurity, particularly, oxygen flow rates mainly influences on increasing (decreasing) at PL peaks. The maximum near of 590-610 nm (˜2 eV), confirming the influence of native defects (oxygen vacancies and interstitials) on the PL intensity and optical quenching exciton peak.

Al Rifai, S. A.; Domashevskaya, E. P.

2013-12-01

206

Zinc oxide hollow microstructures and nanostructures formed under hydrothermal conditions  

SciTech Connect

Zinc oxide low-dimensional hollow structures in the form of hexagonal plates with holes at the center of the {l_brace}0001{r_brace} facets are synthesized in the course of the low-temperature interaction of ZnO precursors with aqueous solutions of potassium fluoride under hydrothermal conditions. Crystals have the shape of single-walled or multiwalled 'nuts.' The high optical quality of the structures is confirmed by cathodoluminescence data at room temperature. The mechanism of the formation of ZnO 'nanonuts' and products of the interaction of the ZnO precursors with KF is proposed.

Dem'yanets, L. N., E-mail: demianets@ns.crys.ras.ru; Artemov, V. V.; Li, L. E.; Mininzon, Yu. M.; Uvarova, T. G. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2008-09-15

207

Random lasing from surface modified films of zinc oxide nanoparticles  

NASA Astrophysics Data System (ADS)

The photoluminescence properties of zinc oxide (ZnO) ceramic thin films, prepared by spin coating of ZnO nanoparticle aqueous suspensions, were studied with emphasis on the influence of film structure and surface morphology on the observation of random laser action. Surface processing employing laser annealing transforms the particulate grain structure of the as-deposited films into a porous channel-like network. This modification was shown to be critical for achieving random laser action as it favors efficient coupling of the pump light into the film material.

Stassinopoulos, A.; Das, R. N.; Giannelis, E. P.; Anastasiadis, S. H.; Anglos, D.

2005-07-01

208

Synthesis and structure analysis of aluminum doped zinc oxide powders  

Microsoft Academic Search

Hexagonal Al-doped zinc oxide (ZnO) powders with a nominal composition of Zn1?x\\u000a Al\\u000a x\\u000a O (0?x?0.028) were synthesized by the co-precipitation method. The contents of the Al element in the samples were measured by the\\u000a inductively coupled plasma-optical emission spectroscopy (ICP-OES) technique. The structures of the Zn1?x\\u000a Al\\u000a x\\u000a O (0?x?0.028) compounds calcined at 1000 and 1200°C have been determined

DengPan Nie; Tao Xue; Yu Zhang; XiangJun Li

2008-01-01

209

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

210

pH-dependent growth of zinc oxide nanorods  

NASA Astrophysics Data System (ADS)

Here we study the effect of pH variation on the dimension and morphology of zinc oxide (ZnO) nanorods grown through hydrothermal process at temperatures less than 100 °C. ZnO nanorods were grown on pre-seeded glass substrates using zinc nitrate hexahydrate as the source of Zn ions and hexamethylenetetramine as the source of hydroxyl ions. The pH of the reaction bath was found to change gradually from 6.4 to 7.3 in 5 h during the growth process. The growth of the ZnO nanorods was observed to be faster, both laterally and longitudinally, when the growth solution was in basic conditions. However, flower petal like ZnO nanostructures were obtained when the growth process was initiated in basic condition (pH 8-12), indicating that initial acidic conditions were required to obtain nanorods with well-defined hexagonal facets. ZnO is known to erode in acidic condition and the final dimension of the nanorods is determined by a competition between crystal growth and etching. ZnO nanorods of different dimensions, both laterally (diameters ranging from 220 nm to 1 ?m) and longitudinally (lengths ranging from 1 to 5.6 ?m) were successfully synthesized using the same concentration of zinc nitrate and hexamine in the reaction bath and the same growth duration of 5 h simply through appropriate control of the pH of the reactant solution between 6 and 7.3.

Baruah, Sunandan; Dutta, Joydeep

2009-04-01

211

Diameter control of ultrathin zinc oxide nanofibers synthesized by electrospinning  

PubMed Central

Electrospinning is a versatile technique, which can be used to generate nanofibers from a rich variety of materials. We investigate the variation of a zinc oxide (ZnO)-polyvinylpyrrolidone (PVP) composite structure in morphology by electrospinning from a series of mixture solutions of ZnO sol–gel and PVP. Calcination conditions for the crystallization of ZnO nanofibers and removal of the PVP component from the ZnO-PVP composite nanofibers were also studied. The progression of the ZnO-PVP composite structure from grains to nanofibers was observed, and ZnO-PVP nanofibers as thin as 29.9?±?0.8 nm on average were successfully fabricated. The size of the resultant ZnO-PVP composite nanofibers was considerably affected by two parameters: the concentrations of zinc acetate and PVP in the precursor solution. The concentration of zinc acetate particularly influenced the diameter distribution of the ZnO-PVP nanofibers. The ZnO-PVP nanofibers could be subsequently converted into ZnO nanofibers of a pure wurtzite phase via calcination in air at 500°C for 2 h.

2014-01-01

212

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...

213

Preparation and gas-sensitivity of ultra-fine zinc-oxide powders from roasted zinc-blended  

Microsoft Academic Search

Ultra-fine zinc oxide is an important versatile semiconductor material, which has attracted attention for its wide range of applications such as solar cell, luminescent and chemical sensors that detect the combustible or toxic gases by virtue of their high sensitivity and stability [1]. The gas sensing mechanism involves the chemisorption of oxygen on the oxide surface followed by charge transfer

Xun Feng; Zhongjun Li; Peiyuan Wang; Yifeng Zhou

2005-01-01

214

A Kinetic study of the reaction of zinc oxide with iron powder  

Microsoft Academic Search

Electric arc furnace (EAF) dusts contain significant quantities of zinc, mostly in the form of zinc oxide. This dust has been\\u000a classified as a hazardous waste due to the presence of lead, cadmium, and hexavalent chromium. It is important that environmentally\\u000a acceptable processes be developed to treat this waste. One possible alternative process would involve reacting the zinc oxide\\u000a in

J. R. Donald; C. A. Pickles

1996-01-01

215

Physical properties of zinc doped tin oxide films prepared by spray pyrolysis technique  

Microsoft Academic Search

The structural and optical properties of pure and zinc doped tin oxide (SnO2) thin films have been studied in detail. Thin films of pure and zinc doped tin oxide (Zn : SnO2) were prepared on Si(1 0 0) and quartz substrates by the spray pyrolysis technique at a substrate temperature of 400 °C. The zinc dopant concentration was varied from

S. Vijayalakshmi; S. Venkataraj; M. Subramanian; R. Jayavel

2008-01-01

216

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

217

Preliminary study on zinc–air battery using zinc regeneration electrolysis with propanol oxidation as a counter electrode reaction  

Microsoft Academic Search

A zinc–air battery using zinc regeneration electrolysis with propanol oxidation as a counter electrode reaction is reported in this paper. It possesses functions of both zincate reduction and electrochemical preparation, showing the potential for increasing the electronic energy utilization. Charge\\/discharge tests and scanning electron microscopy (SEM) micrographs reveal that when a nickel sheet plated with the high-H2-overpotential metal, cadmium, was

Yue-Hua Wen; Jie Cheng; Shang-Qi Ning; Yu-Sheng Yang

2009-01-01

218

The electronic structure of co-sputtered zinc indium tin oxide thin films  

Microsoft Academic Search

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

Paz Carreras; Sebastian Gutmann; Aldrin Antony; Joan Bertomeu; Rudy Schlaf

2011-01-01

219

Direct hydrogenation of aromatic carboxylic acids to their corresponding aldehydes with zinc oxide catalysts  

Microsoft Academic Search

High yields of aromatic aldehydes were obtained by direct hydrogenation of aromatic carboxylic acids over different zinc oxide catalysts having distinctive surface properties. The reaction is carried out in a fixed bed reactor in gas phase at 330–350°C. High selectivity of 96% of benzaldehyde at 100% conversion of benzoic acid was achieved using a zinc oxide catalyst having very weakly

W. F. Hölderich; J. Tjoe

1999-01-01

220

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

221

Triclinic-structure composite oxide containing zinc and tungsten and phosphor  

US Patent & Trademark Office Database

There are provided a composite oxide of a triclinic crystal system comprising zinc and tungsten, and a production method thereof. Further, there is provided a light-emitting material comprising the composite oxide of triclinic crystal system comprising zinc and tungsten.

2009-03-10

222

Heat-Sterilized Silver Oxide-Zinc Cells Cycle Life Studies.  

National Technical Information Service (NTIS)

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 A-h were fabricated using zinc oxide electrodes prepared by th...

J. T. Arms

1973-01-01

223

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

224

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

225

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

226

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

NASA Astrophysics Data System (ADS)

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·3B 2O 3·3.5H 2O. Effects of stirring speed, presence of baffles, amount of seed, particle size and purity of zinc oxide, and mole ratio of H 3BO 3:ZnO on the zinc borate formation reaction were examined at a constant temperature of 85 °C in a laboratory (4 L) and a pilot scale (85 L) reactor. Products obtained from the reaction in both reactors were characterized by chemical analysis, X-ray diffraction, particle size distribution analysis, thermal gravimetric analysis and scanning electron microscopy. The kinetic data for the zinc borate production reaction was fit by using the logistic model. The results revealed that the specific reaction rate, a model parameter, decreases with increase in particle size of zinc oxide and the presence of baffles, but increases with increase in stirring speed and purity of zinc oxide; however, it is unaffected with the changes in the amount of seed and reactants ratio. The reaction completion time is unaffected by scaling-up.

K?l?nç, Mert; Çakal, Gaye Ö.; Ye?il, Sertan; Bayram, Göknur; Ero?lu, ?nci; Özkar, Saim

2010-11-01

227

Ferrate(VI) oxidation of zinc-cyanide complex.  

PubMed

Zinc-cyanide complexes are found in gold mining effluents and in metal finishing rinse water. The effect of Zn(II) on the oxidation of cyanide by ferrate(VI) (Fe(VI)O(4)(2-), Fe(VI)) was thus investigated by studying the kinetics of the reaction of Fe(VI) with cyanide present in a potassium salt of a zinc cyanide complex (K(2)Zn(CN)(4)) and in a mixture of Zn(II) and cyanide solutions as a function of pH (9.0-11.0). The rate-law for the oxidation of Zn(CN)(4)(2-) by Fe(VI) was found to be -d[Fe(VI)]/dt=k[Fe(VI)][Zn(CN)(4)(2-)](0.5). The rate constant, k, decreased with an increase in pH. The effect of temperature (15-45 degrees C) on the oxidation was studied at pH 9.0, which gave an activation energy of 45.7+/-1.5kJmol(-1). The cyanide oxidation rate decreased in the presence of the Zn(II) ions. However, Zn(II) ions had no effect on the cyanide removal efficiency by Fe(VI) and the stoichiometry of Fe(VI) to cyanide was approximately 1:1; similar to the stoichiometry in absence of Zn(II) ions. The destruction of cyanide by Fe(VI) resulted in cyanate. The experiments on removal of cyanide from rinse water using Fe(VI) demonstrated complete conversion of cyanide to cyanate. PMID:17597180

Yngard, Ria; Damrongsiri, Seelawut; Osathaphan, Khemarath; Sharma, Virender K

2007-10-01

228

Nanosized zinc oxide induces toxicity in human lung cells.  

PubMed

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. PMID:23997968

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

2013-01-01

229

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

PubMed Central

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.

2013-01-01

230

Catalytic wet peroxide oxidation of azo dye (Direct Blue 15) using solvothermally synthesized copper hydroxide nitrate as catalyst  

Microsoft Academic Search

Copper hydroxide nitrate (Cu2(OH)3NO3) was synthesized solvothermally in anhydrous ethanol and characterized by XRD, FTIR, TG–DTA and SEM. The peroxide degradation of an azo dye (Direct Blue 15) on this material was evaluated by examining catalyst loading, initial pH, hydrogen peroxide dosage, initial dye concentration and temperature. The leaching of Cu from the copper hydroxide nitrate during the reaction was

Yuzhong Zhan; Xiang Zhou; Bei Fu; Yiliang Chen

2011-01-01

231

1-Dimensional Zinc Oxide Nanomaterial Growth and Solar Cell Applications  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) has attracted much interest during last decades as a functional material. Furthermore, ZnO is a potential material for transparent conducting oxide material competing with indium tin oxide (ITO), graphene, and carbon nanotube film. It has been known as a conductive material when doped with elements such as indium, gallium and aluminum. The solubility of those dopant elements in ZnO is still debatable; but, it is necessary to find alternative conducting materials when their form is film or nanostructure for display devices. This is a consequence of the ever increasing price of indium. In addition, a new generation solar cell (nanostructured or hybrid photovoltaics) requires compatible materials which are capable of free standing on substrates without seed or buffer layers and have the ability introduce electrons or holes pathway without blocking towards electrodes. The nanostructures for solar cells using inorganic materials such as silicon (Si), titanium oxide (TiO2), and ZnO have been an interesting topic for research in solar cell community in order to overcome the limitation of efficiency for organic solar cells. This dissertation is a study of the rational solution-based synthesis of 1-dimentional ZnO nanomaterial and its solar cell applications. These results have implications in cost effective and uniform nanomanufacturing for the next generation solar cells application by controlling growth condition and by doping transition metal element in solution.

Choi, Hyung Woo

232

Zinc oxide and related compounds: order within the disorder  

NASA Astrophysics Data System (ADS)

This paper discusses the effect of order and disorder on the electrical and optical performance of ionic oxide semiconductors based on zinc oxide. These materials are used as active thin films in electronic devices such as pn heterojunction solar cells and thin-film transistors. Considering the expected conduction mechanism in ordered and disordered semiconductors the role of the spherical symmetry of the s electron conduction bands will be analyzed and compared to covalent semiconductors. The obtained results show p-type c-Si/a-IZO/poly-ZGO solar cells exhibiting efficiencies above 14%, in device areas of about 2.34 cm2. Amorphous oxide TFTs based on the Ga-Zn-Sn-O system demonstrate superior performance than the polycrystalline TFTs based on ZnO, translated by ION/IOFF ratio exceeding 107, turn-on voltage below 1-2 V and saturation mobility above 25 cm2/Vs. Apart from that, preliminary data on p-type oxide TFT based on the Zn-Cu-O system will also be presented.

Martins, R.; Pereira, Luisa; Barquinha, P.; Ferreira, I.; Prabakaran, R.; Goncalves, G.; Goncalves, A.; Fortunato, E.

2009-02-01

233

Influence of boron oxide on protective properties of zinc coating on steel  

SciTech Connect

The authors study the properties of zinc coating when boron oxide is added to the melt for galvanization. The authors found that a rise in the degree of initial deformation of the steel leads to the production of varying thickness of the zinc coating. The results show the favorable influence of small amounts of added boron oxide on the corrosion resistance of a zinc coating on cold-deformed high-carbon steel; this influence is also manifested in the case of deformation of the zinc coating itself.

Alimov, V.I.; Berezin, A.V.

1986-05-01

234

Active material redistribution rates in zinc electrodes: Effect of alkaline electrolyte compositions having reduced zinc oxide solubility  

NASA Astrophysics Data System (ADS)

Electrolytes with low hydroxide concentration were tested in 1.35 Ah tri-electrode Zn/NiOOH cells for their ability to reduce zinc redistribution rates. Three electrolytes were evaluated: a 3.5M OH(-) electrolyte, a 3.5M OH(-) to 3.4M F(-) electrolyte, and a hydroxide-borate electrolyte. The electrolytes were chosen to have a ZnO solubility approximately 25% of that in the standard 30% KOH-1% LiOH electrolyte (7.4 M OH(-)). A 6 hour charge rate and a 2.5 hour discharge rate were employed for the Teflon bonded, zinc oxide electrodes, to which 2% PbO was added to reduce hydrogen evolution. It was found that the zinc redistribution rates are lower for the electrolytes with reduced ZnO solubility. In addition, no zinc penetration of the separator occurred for some of the electrolytes, even with overpotentials of 100 to 290 mV. After 125 cycles, none of the cell capacities were limited by the zinc electrode during discharge, less than 2% inactive zinc was found in the zinc electrodes cycled in the hydroxide-fluoride and borate electrolytes.

Nichols, J. T.; McLarnon, F. R.; Cairns, E. J.

1983-11-01

235

Zinc  

MedlinePLUS

... viruses . The body also needs zinc to make proteins and DNA , the genetic material in all cells. ... colitis or Crohn's disease . These conditions can both decrease the amount of zinc that the body absorbs ...

236

a Comprehensive DFT Study of Zinc Oxide in Different Phases  

NASA Astrophysics Data System (ADS)

A density functional study for structural and electronic properties of Zinc Oxide (ZnO), in wurtzite, rock salt and zinc-blende phases has been performed using full potential-linearized augmented plane wave/linearized augmented plane wave plus local ideal orbital (FP-LAPW/L(APW+lo) approach as realized in WIEN2k code. To approximate exchange correlation energy and corresponding potential, a special GGA parameterized by Wu-Cohen has been implemented. Our results of lattice constants, bulk moduli as well as for internal parameter with GGA-WC are found to be more reliable. This study reveals that value of internal parameter decreases with increasing volume whereas computed electronic band structure confirms the direct band gap behavior of ZnO in B4 and B3 phases while indirect band gap behavior in B1 phase. Moreover, two fold degeneracy at the maxima of valence band for B4 and B1 phases whereas three fold for B3 is observed. A detailed comparison with experimental and other first principles studies is also made.

Ul Haq, Bakhtiar; Afaq, A.; Ahmed, R.; Naseem, S.

2012-06-01

237

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

PubMed Central

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.

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

2014-01-01

238

Physiological characterization of the Arabidopsis thaliana Oxidation-related Zinc Finger 1, a plasma membrane protein involved in oxidative stress  

Microsoft Academic Search

The CCCH-type zinc finger proteins are a superfamily containing tandem zinc-binding motifs involved in many aspects of plant\\u000a growth and development. However, the precise role of these proteins involved in plant stress tolerance is poorly understood.\\u000a This study was to examine the regulatory and functional role of the CCCH-type zinc finger protein, AtOZF1 (At2g19810), under oxidative stress. Interestingly, the AtOZF1

Ping Huang; Moon-Soo Chung; Hyun-Woo Ju; Hyun-Seok Na; Dong Ju Lee; Hyeon-Sook Cheong; Cheol Soo Kim

239

Improved conductivity and mechanism of carrier transport in zinc oxide with embedded silver layer  

Microsoft Academic Search

The effects of an embedded silver layer on the electrical and optical properties of zinc oxide (ZnO)\\/silver (Ag)\\/zinc oxide (ZnO) layered composite structures on polymer substrates have been investigated. We have engineered transparent conducting oxide structures with greatly improved conductivity. Optical and electrical properties are correlated with Ag thickness. Film thicknesses were determined using Rutherford backscattering spectrometry. Hall effect, four-point

H. Han; N. D. Theodore; T. L. Alford

2008-01-01

240

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

NASA Astrophysics Data System (ADS)

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 nanostructures could have novel applications in optoelectronics, sensors, transducers and biomedical sciences. This article reviews the various nanostructures of ZnO grown by the solid-vapour phase technique and their corresponding growth mechanisms. The application of ZnO nanobelts as nanosensors, nanocantilevers, field effect transistors and nanoresonators is demonstrated.

Wang, Zhong Lin

2004-06-01

241

Stability of zinc oxide nanofluids prepared with aggregated nanocrystalline powders.  

PubMed

Aqueous zinc oxide (ZnO) suspensions were prepared using a two-step preparation method in which an aggregated nanocrystalline ZnO powder was dispersed in water using a polyelectrolyte. The fluid showed anomalously high thermal conductivity when compared with the Maxwell and Hamilton-Crosser predictions. However, analysis of the particle size distribution showed that the fluid contained aggregated 20 nm crystallites of ZnO with a high volume fraction of particles larger than 100 nm. Sedimentation experiments revealed that particles settled out of the stationary fluid over times ranging from 0.1 hours to well over 10,000 hours. The size of the particles remaining in suspension agreed well with predictions made using Stoke's law, suggesting flocculation was not occurring in the fluids. Finally, a new concept of nanofluid stability is introduced based on the height of the fluid, sedimentation, Brownian motion and the kinetic energy of the particles. PMID:19205207

Leonard, J P; Chung, S J; Nettleship, I; Soong, Y; Martello, D V; Chyu, M K

2008-12-01

242

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

243

Zinc/nickel oxide battery membrane separator studies  

NASA Astrophysics Data System (ADS)

Fourteen different macrocyclic compounds were synthesized for possible use in anionic exchange membranes and several polymerized with polyvinylbenzyl chloride. Two others were used in polyvinyl alcohol (PVA) membranes. Work continued to develop a suitable polymer material for the membranes. PVA could be cross-linked using a crown-ether dialdehyde as a cross-linking agent to produce a membrane with high ionic conductivity (0.02 mho/cm) and reasonable short-term stability in strong caustic solution at room temperatures. Selectivity of the membrane for hydroxide ions was essentially the same as that in the solution itself. Two new fabrication methods for polypropylene membranes were investigated and developed. Development of a two-dimensional code of a zinc-nickel oxide cell was begun.

Bennion, D. N.; Bradshaw, J. S.

1986-03-01

244

Reduction of aromatic nitro compounds with hydrazine hydrate in the presence of an iron oxide\\/hydroxide catalyst. III. The selective reduction of nitro groups in aromatic azo compounds  

Microsoft Academic Search

The study on the range of applications of a cheap iron oxide\\/hydroxide modification as a H-transfer catalyst opened up a promising new route for the selective reduction of nitro groups in aromatic azo compounds. A series of monosubstituted 3- and 4-nitrophenylazobenzenes were reduced selectively by hydrazine hydrate in the presence of the iron oxide\\/hydroxide catalyst. The selectivity for the nitro

Max Lauwiner; Ronny Roth; Paul Rys

1999-01-01

245

Texture and Topography Analysis of Doxycycline Hyclate Thermosensitive Systems Comprising Zinc Oxide  

PubMed Central

To characterize the thermal behavior and texture analysis of doxycycline hyclate thermosensitive gels developed for periodontitis treatment containing zinc oxide prepared by using poloxamer (Lutrol® F127) as polymeric material and N-methyl pyrrolidone was used as cosolvent. The thermosensitive gel comprising doxycycline hyclate, Lutrol® F127, and N-methyl pyrrolidone were characterized for the thermal behavior and texture analysis. The topography of the system after the dissolution test was characterized with scanning electron microscope. Differential scanning calorimetric thermogram exhibited the endothermic peaks in the systems containing high amount of N-methyl pyrrolidone in solvent. The sol-gel transition temperature of the systems decreased as the zinc oxide amount was increased. The addition of doxycycline hyclate, zinc oxide, and N-methyl pyrrolidone affected the syringeability of systems. The addition of zinc oxide into the doxycycline hyclate-Lutrol® F127 systems decreased the diameter of inhibition zone against Staphylococcus aureus, Escherichia coli, and Candida albicans since zinc oxide decreased the diffusion and prolonged release of doxycycline hyclate. From scanning electron microscope analysis, the porous surface of 20% w/w Lutrol® F127 system was notably different from that of gel comprising doxycycline hyclate which had interconnected pores and smooth surfaces. The number of pores was decreased with increasing zinc oxide and the porous structure was smaller and more compact. Therefore, the addition of zinc oxide could increase the syringeability of doxycycline hyclate-Lutrol® F127 system with the temperature dependence. Zinc oxide decreased inhibition zone against test microbes because of prolongation of doxycycline hyclate release and reduced size of continuous cells. Furthermore, zinc oxide also increased the compactness of wall surfaces of Lutrol® F127.

Phaechamud, T.; Mahadlek, J.; Charoenteeraboon, J.

2013-01-01

246

Texture and topography analysis of doxycycline hyclate thermosensitive systems comprising zinc oxide.  

PubMed

To characterize the thermal behavior and texture analysis of doxycycline hyclate thermosensitive gels developed for periodontitis treatment containing zinc oxide prepared by using poloxamer (Lutrol(®) F127) as polymeric material and N-methyl pyrrolidone was used as cosolvent. The thermosensitive gel comprising doxycycline hyclate, Lutrol(®) F127, and N-methyl pyrrolidone were characterized for the thermal behavior and texture analysis. The topography of the system after the dissolution test was characterized with scanning electron microscope. Differential scanning calorimetric thermogram exhibited the endothermic peaks in the systems containing high amount of N-methyl pyrrolidone in solvent. The sol-gel transition temperature of the systems decreased as the zinc oxide amount was increased. The addition of doxycycline hyclate, zinc oxide, and N-methyl pyrrolidone affected the syringeability of systems. The addition of zinc oxide into the doxycycline hyclate-Lutrol(®) F127 systems decreased the diameter of inhibition zone against Staphylococcus aureus, Escherichia coli, and Candida albicans since zinc oxide decreased the diffusion and prolonged release of doxycycline hyclate. From scanning electron microscope analysis, the porous surface of 20% w/w Lutrol(®) F127 system was notably different from that of gel comprising doxycycline hyclate which had interconnected pores and smooth surfaces. The number of pores was decreased with increasing zinc oxide and the porous structure was smaller and more compact. Therefore, the addition of zinc oxide could increase the syringeability of doxycycline hyclate-Lutrol(®) F127 system with the temperature dependence. Zinc oxide decreased inhibition zone against test microbes because of prolongation of doxycycline hyclate release and reduced size of continuous cells. Furthermore, zinc oxide also increased the compactness of wall surfaces of Lutrol(®) F127. PMID:24302791

Phaechamud, T; Mahadlek, J; Charoenteeraboon, J

2013-07-01

247

Effect of zinc supplementation on resistance of cultured human skin fibroblasts toward oxidant stress  

Microsoft Academic Search

In purified system zinc has been shown to have an antioxidant role. Its effects on the resistance of cultured cells towards\\u000a oxidative stress in vitro were examined. Diploid human skin fibroblasts were grown for 21 d in culture media (RPMI 1640 containing\\u000a 15% fetal calf serum) added with different zinc (Zn) concentrations (100, 125, and 150?M as Zinc chlorur ZnCl2).

Marie-Jeanne Richard; Pascale Guiraud; Marie-Therese Leccia; Jean-Claude Beani; Alain Favier

1993-01-01

248

Nano-encapuslated of zinc sulfide:silver with indium tin oxide and aluminum doped zinc oxide for flat panel display applications  

Microsoft Academic Search

Reduction in cathodoluminescent degradation through the application of nanometer thick films of indium tin oxide (ITO) and aluminum doped zinc oxide (ZAO) has been investigated using x-ray photoelectron spectroscopy (XPS), cathodoluminescent degradation, scanning electron microscopy, transmission electron spectroscopy, and optical spectrometry. The partial pressure of water and the oxygen deposition pressure used during the coating process were controlled as parameters

Michael Ollinger

2002-01-01

249

Transparent Oxide Thin-Film Transistors Composed of Al and Sn-doped Zinc Indium Oxide  

Microsoft Academic Search

We have fabricated the transparent bottom gate thin-film transistors (TFTs) using Al and Sn-doped zinc indium oxide (AT-ZIO) as an active layer. The AT-ZIO active layer was deposited by RF magnetron sputtering at room temperature, and the AT-ZIO TFT showed a field effect mobility of 15.6 cm2\\/Vs even before annealing. The mobility increased with increasing the In2O3 content and postannealing

Doo-Hee Cho; Shinhyuk Yang; Chunwon Byun; Min Ki Ryu; Sang-Hee Ko Park; Chi-Sun Hwang; Sung Min Yoon; Hye-Yong Chu

2009-01-01

250

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

SciTech Connect

We report an enhancement effect of ultraviolet illumination on the photoluminescence intensities of zinc oxide thin films. Large-grain <0001>-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 radiation enhancement effect to oxygen desorption on the surface of the zinc oxide thin film. We have proposed a phenomenological model to explain this interesting photoluminescence behavior.

Jin Chunming; Tiwari, Ashutosh; Narayan, Roger J. [Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina 27695-7575 (United States); Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7907 (United States); Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina 27695-7575 (United States)

2005-10-15

251

[Azo derivatives of levorin].  

PubMed

Levorin, an aromatic heptaenic antibiotic and sodium nitrite in solution of acetic acid formed a diazo compound. In the diazo reaction this compound interacted with beta-napthol or H-acid. The resulting azo compounds were readily soluble in organic solvents. In water their nitrites formed true solutions. The biological activity of the azo levorins was 100-200 times lower than that of the initial levorin. The physico-chemical characteristics of the azo levorins are presented. PMID:3947046

Mitrofanov, A A; Shenin, Iu D; Mitrofanova, V G

1986-01-01

252

Development of sealed silver oxide--zinc secondary batteries. Final report  

Microsoft Academic Search

Research and development program was conducted to provide a hermetically sealed silver oxide--zinc battery for use in satellite applications. Problem areas considered were silver migration in cell, battery voltage regulation, zinc particle size and displacement during cycling, gas evolution, and terminal sealing. Sealed cells were designed, constructed, and tested electrically and environmentally.

J. J. Lander; J. A. Keralla

1962-01-01

253

Microstructural investigations and paramagnetic susceptibilities of zinc oxide, europium oxide and their nanocomposite  

Microsoft Academic Search

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 6h. The X-ray diffractograms (XRD) confirmed the formation of desired phases of the

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

2010-01-01

254

Low temperature polymeric precursor derived zinc oxide thin films  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) is a versatile environmentally benign II-VI direct wide band gap semiconductor with several technologically plausible applications such as transparent conducting oxide in flat panel and flexible displays. Hence, ZnO thin films have to be processed below the glass transition temperatures of polymeric substrates used in flexible displays. ZnO thin films were synthesized via aqueous polymeric precursor process by different metallic salt routes using ethylene glycol, glycerol, citric acid, and ethylene diamine tetraacetic acid (EDTA) as chelating agents. ZnO thin films, derived from ethylene glycol based polymeric precursor, exhibit flower-like morphology whereas thin films derived of other precursors illustrate crack free nanocrystalline films. ZnO thin films on sapphire substrates show an increase in preferential orientation along the (002) plane with increase in annealing temperature. The polymeric precursors have also been used in fabricating maskless patterned ZnO thin films in a single step using the commercial Maskless Mesoscale Materials Deposition (M3D(TM)) system.

Choppali, Uma

255

Pharmacokinetics, tissue distribution, and excretion of zinc oxide nanoparticles  

PubMed Central

Background This study explored the pharmacokinetics, tissue distribution, and excretion profile of zinc oxide (ZnO) nanoparticles with respect to their particle size in rats. Methods Two ZnO nanoparticles of different size (20 nm and 70 nm) were orally administered to male and female rats, respectively. The area under the plasma concentration-time curve, tissue distribution, excretion, and the fate of the nanoparticles in organs were analyzed. Results The plasma zinc concentration of both sizes of ZnO nanoparticles increased during the 24 hours after administration in a dose-dependent manner. They were mainly distributed to organs such as the liver, lung, and kidney within 72 hours without any significant difference being found according to particle size or rat gender. Elimination kinetics showed that a small amount of ZnO nanoparticles was excreted via the urine, while most of nanoparticles were excreted via the feces. Transmission electron microscopy and x-ray absorption spectroscopy studies in the tissues showed no noticeable ZnO nanoparticles, while new Zn-S bonds were observed in tissues. Conclusion ZnO nanoparticles of different size were not easily absorbed into the bloodstream via the gastrointestinal tract after a single oral dose. The liver, lung, and kidney could be possible target organs for accumulation and toxicity of ZnO nanoparticles was independent of particle size or gender. ZnO nanoparticles appear to be absorbed in the organs in an ionic form rather than in a particulate form due to newly formed Zn-S bonds. The nanoparticles were mainly excreted via the feces, and smaller particles were cleared more rapidly than the larger ones. ZnO nanoparticles at a concentration below 300 mg/kg were distributed in tissues and excreted within 24 hours. These findings provide crucial information on possible acute and chronic toxicity of ZnO nanoparticles in potential target organs.

Baek, Miri; Chung, Hae-Eun; Yu, Jin; Lee, Jung-A; Kim, Tae-Hyun; Oh, Jae-Min; Lee, Won-Jae; Paek, Seung-Min; Lee, Jong Kwon; Jeong, Jayoung; Choy, Jin-Ho; Choi, Soo-Jin

2012-01-01

256

Chemical states and ferromagnetism in heavily Mn-substituted zinc oxide thin films  

NASA Astrophysics Data System (ADS)

A concentration of Manganese as high as 8% was successfully diluted into Zinc Oxide epitaxial films deposited by pulsed laser deposition. The films showed strong ferromagnetism with a large coercivity. Low temperature X-ray absorption spectroscopy measurements indicated that all the Manganese ions substitute for Zinc sites of the wurtzite lattice in the valency of +2. Photoluminescence measurements excluded the presence of Zinc vacancies, as well as Zn interstitials. All the magnetic moments measured were to ascribe to the formation of bound magnetic polarons, with no other contribution due to Manganese-secondary phases or Zinc vacancy-mediated double exchange interaction.

Shao, Q.; Ku, P. S.; Wang, X. L.; Zapien, J. A.; Leung, C. W.; Borgatti, F.; Gambardella, A.; Dediu, V.; Ciprian, R.; Ruotolo, A.

2014-04-01

257

Zinc oxide thin films and nanostructures for optoelectronic applications  

NASA Astrophysics Data System (ADS)

The objective of this research focuses on investigating optical, electrical, and structural properties of Al doped ZnO (AZO) and developing novel approaches to demonstrate and improve the photovoltaics and photodetectors by introducing AZO nanoscaled structures. ZnO has been widely studied for optoelectronic applications such as light emitting diodes, lasers and photodiodes covering the ultraviolet spectrum because of its wide and direct bandgap and high exciton binding energy. In this research, aluminum doped ZnO films were grown by a dual beam sputtering method which is a combination of RF sputtered ZnO and DC sputtered Al. Various approaches were applied to characterize its optical, electrical and structural modulation in terms of growth parameters and doping parameters. As an n-type dopant, Al doping was controlled from 5x016 to 5x0 20 cm-3 maintaining visible transparency with a wider transparency as Al increased, and high mobility ( 2 ˜ 14 cm2/V.s). For the optoelectric applications, a ZnO/Si heterojunction was demonstrated and studied regarding Al doping effects on the anisotype and isotype junction. An unlikely conventional photovoltaic structure suggested the ZnO/Si solar cell to be advantageous in terms of low cost fabrication process -- low temperature, no diffusion, and large area processing. In this structure, AZO plays a role as a transparent current spreading layer and rectifying junction with silicon (Si). Furthermore, by introducing metal nanostructures inside of the AZO film, light harvesting was enhanced because of plasmonic and light scattering effects ensuring minimized electrical and optical loss within the AZO. To improve photovoltaic performance, a transparent and conductive nanolens array was embedded on ITO film and employed on a conventional Si solar cell using large scale nanoimprint method. The proposed structure provides superior optical transparency beyond 700 nm of wavelength and omnidirectional broadband low reflectivity as well as good electrical conductivity. The nanolens array collimates the long wavelength energy into a shallow depth of Si, showing improved charge collection efficiency. Moreover, wave coupling in the nanolens uncovered region focuses the energy in a more shallow depth as an absorber.

Yun, Juhyung

258

Review of Membrane Separators and Zinc-Nickel Oxide Battery Development.  

National Technical Information Service (NTIS)

After a discussion of membranes and their role in zinc-nickel oxide batteries, possible solutions are reviewed for problems related to membrane separators in these batteries. Experiments to characterize a membrane are also summarized. A bibliography is in...

D. N. Bennion

1980-01-01

259

Preparation and Characterization of Quantum Size Zinc Oxide: A Detailed Spectroscopic Study.  

National Technical Information Service (NTIS)

The synthesis of transparent colloidal suspensions of small zinc oxide particles in water, 2-propanol, and acetonitrile are reported. Quantum(Q)-size effects are observed during particle growth and qualitatively interpreted using a simple molecular orbita...

D. W. Bahnemann C. Kormann M. R. Hoffmann

1987-01-01

260

Flexible and monolithic zinc oxide bionanocomposite foams by a bacterial cellulose mediated approach for antibacterial applications.  

PubMed

The use of self-assembled biomacromolecules in the development of functional bionanocomposite foams is one of the best lessons learned from nature. Here, we show that monolithic, flexible and porous zinc oxide bionanocomposite foams with a hierarchical architecture can be assembled through the mediation of bacterial cellulose. The assembly is achieved by controlled hydrolysis and solvothermal crystallization using a bacterial cellulose aerogel as a template in a non-aqueous polar medium. The bionanocomposite foam with a maximum zinc oxide loading of 70 wt% is constructed of intimately packed spheres of aggregated zinc oxide nanocrystals exhibiting a BET surface area of 92 m(2) g(-1). The zinc oxide bionanocomposite foams show excellent antibacterial activity, which give them potential value as self-supporting wound dressing and water sterilization materials. PMID:24647467

Wang, Peipei; Zhao, Jun; Xuan, Ruifei; Wang, Yun; Zou, Chen; Zhang, Zhiquan; Wan, Yizao; Xu, Yan

2014-05-14

261

Burn-induced oxidative stress is altered by a low zinc status: kinetic study in burned rats fed a low zinc diet  

PubMed Central

As an initial subdeficient status of zinc, considered as an essential antioxidant trace element, is frequent in burned patients, we aim to assess the effects of low zinc dietary intakes on burn induced oxidative stress, in an animal model. After eight weeks of conditioning diets containing 80 ppm (control group) or 10 ppm of zinc (depleted group), Wistar rats were 20% TBSA burned and sampled one to ten days after injury. Kinetic evolutions of zinc status, plasma oxidative stress parameters and antioxidant enzymes were also studied in blood and organs. The zinc depleted diet induced, before injury, a significant decrease in zinc bone level and the increase of oxidative stress markers without stimulation of antioxidant enzyme activity. After burn, more markedly in zinc depleted animals than in controls, zinc levels decreased in plasma and bone, while increasing in liver. The decrease of thiol groups and GSH/GSSG ratio and the depression of GPx activity in liver are also moderately emphasized. Nevertheless, depleted zinc status could not be considered as determining for oxidative damages after burn injury. Further investigations must also be done to enlighten the mechanism of beneficial effects of zinc supplementation reported in burned patients.

Claeyssen, Richard; Andriollo-Sanchez, Maud; Arnaud, Josiane; Touvard, Laurence; Alonso, Antonia; Chancerelle, Yves; Roussel, Anne-Marie; Agay, Diane

2008-01-01

262

Zinc ion enhances GABA tea-mediated oxidative DNA damage.  

PubMed

GABA tea is a tea product that contains a high level of ?-aminobutyric acid (GABA). Previous study has demonstrated a synergistic effect of GABA tea and copper ions on DNA breakage. This study further explored whether zinc (Zn), a nonredox metal, modulated DNA cleavage induced by GABA tea extract. In a cell-free system, Zn(2+) significantly enhanced GABA tea extract and (-)-epigallocatechin-3-gallate (EGCG)- or H(2)O(2)-induced DNA damage at 24 h of incubation. Additionally, low dosages of GABA tea extract (1-10 ?g/mL) possessed pro-oxidant activity to increase H(2)O(2)/Zn(2+)-induced DNA cleavage in a dose-dependent profile. By use of various reactive oxygen scavengers, it was observed that glutathione, catalase, and potassium iodide effectively inhibited DNA degradation caused by the GABA tea extract/H(2)O(2)/Zn(2+) system. Moreover, the data showed that the GABA tea extract itself (0.5-5 mg/mL) could induce DNA cleavage in a long-term exposure (48 h). EGCG, but not the GABA tea extract, enhanced H(2)O(2)-induced DNA cleavage. In contrast, GABA decreased H(2)O(2)- and EGCG-induced DNA cleavage, suggesting that GABA might contribute the major effect on the antioxidant activity of GABA tea extract. Furthermore, a comet assay revealed that GABA tea extract (0.25 mg/mL) and GABA had antioxidant activity on H(2)O(2)-induced DNA breakage in human peripheral lymphocytes. Taken together, these findings indicate that GABA tea has the potential of both pro-oxidant and antioxidant. It is proposed that a balance between EGCG-induced pro-oxidation and GABA-mediated antioxidation may occur in a complex mixture of GABA tea extract. PMID:22264004

Chuang, Show-Mei; Wang, Hsueh-Fang; Hsiao, Ching-Chuan; Cherng, Shur-Hueih

2012-02-15

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

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

265

Kinetics of the reactions of carbon containing zinc oxide composites under microwave irradiation  

Microsoft Academic Search

As a fundamental study for the recycling of EAF dust using microwave heating, the reduction rate of a zinc oxide composite\\u000a by solid carbon under microwave irradiation was investigated. It was found that the reduction of zinc oxide by solid carbon\\u000a under microwave irradiation was much faster than the conventional method, and the activation energy for the reaction under\\u000a microwave

Eunju Kim; Seungyoun Cho; Joonho Lee

2009-01-01

266

Effect of mixing conditions on irritant potency of zinc oxide and sulfur dioxide. [Guinea pigs  

Microsoft Academic Search

Measurement of mechanics of respiration in guinea pigs was used to assess the irritant potency of zinc oxide and sulfur dioxide mixed under different conditions of temperature and humidity. Concentrations were 1-2 mg\\/m³ zinc oxide and 1 ppm sulfur dioxide. Dry conditions of mixing (Chamber RH 30%) either at 24°C in the exposure chamber or at 480°C in a dry

M. O. Amdur; J. F. McCarthy; M. W. Gill

1983-01-01

267

Effect of Mixing Conditions on Irritant Potency of Zinc Oxide and Sulfur Dioxide  

Microsoft Academic Search

Measurement of mechanics of respiration in guinea pigs was used to assess the irritant potency of zinc oxide and sulfur dioxide mixed under different conditions of temperature and humidity. Concentrations were 1-2?mg\\/m zinc oxide and 1?ppm sulfur dioxide. Dry conditions of mixing (Chamber RH 30%) either at 24°C in the exposure chamber or at 480°C in a dry furnace gave

MARY O. AMDUR; JOHN F. McCARTHY; MICHAEL W. GILL

1983-01-01

268

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

269

Zinc oxide nanowire arrays for silicon core/shell solar cells.  

PubMed

The optics of core / shell nanowire solar cells was investigated. The optical wave propagation was studied by finite difference time domain simulations using realistic interface morphologies. The interface morphologies were determined by a 3D surface coverage algorithm, which provides a realistic film formation of amorphous silicon films on zinc oxide nanowire arrays. The influence of the nanowire dimensions on the interface morphology and light trapping was investigated and optimal dimensions of the zinc oxide nanowire were derived. PMID:24922370

Tamang, Asman; Pathirane, Minoli; Parsons, Rion; Schwarz, Miriam M; Iheanacho, Bright; Jovanov, Vladislav; Wagner, Veit; Wong, William S; Knipp, Dietmar

2014-05-01

270

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

271

Physical properties and growth kinetics of co-sputtered indium-zinc oxide films  

Microsoft Academic Search

Indium-doped zinc oxide (IZO) films were fabricated by radio-frequency (RF) magnetron sputtering through co-deposition of zinc oxide (ZnO) and indium (In) at ambient temperature. Transparency of the IZO films is higher than 80% in the visible range while the optical band gap decreases with increasing In dopant concentration. The optimal measured resistivity, Hall mobility and carrier concentration of the film

Changgang Huang; Meili Wang; Quanlin Liu; Yongge Cao; Zhonghua Deng; Zhi Huang; Yuan Liu; Qiufeng Huang; Wang Guo

2009-01-01

272

Intra-shell luminescence of transition-metal-implanted zinc oxide nanowires  

Microsoft Academic Search

Zinc oxide nanowires were grown by vapor transport using the vapor-liquid-solid growth mechanism. The zinc oxide nanowires were implanted with transition metals (Co, Fe or Ni) and subsequently annealed in air at 700 °C for 30 min. Energy-dispersive x-ray spectroscopy and electron energy loss spectroscopy measurements reveal a successful incorporation of the desired transition metals. Transmission electron microscopy analysis of

Sven Müller; Minjie Zhou; Quan Li; Carsten Ronning

2009-01-01

273

Mechanistic study on electrochemical codeposition of mixed zinc–erbium oxide films on the cathodic surface  

Microsoft Academic Search

Erbium doped zinc oxide thin films were prepared from aqueous solutions containing Zn(NO3)2 and Er(NO3)3 by the potentiostatic technique using a three-electrode system. The pH changes at the cathode\\/solution interface were in-situ measured during the electrodeposition process of mixed erbium–zinc hydroxide or oxide films. The solution- and solid-phase speciation distributions of the two metal ions and their hydroxides as a

Jian-Min Zhang; Xiang-Ming Feng

2008-01-01

274

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

275

Zinc Supplementation Prevents Alcoholic Liver Injury in Mice through Attenuation of Oxidative Stress  

PubMed Central

Alcoholic liver disease is associated with zinc decrease in the liver. Therefore, we examined whether dietary zinc supplementation could provide protection from alcoholic liver injury. Metallothionein-knockout and wild-type 129/Sv mice were pair-fed an ethanol-containing liquid diet for 12 weeks, and the effects of zinc supplementation on ethanol-induced liver injury were analyzed. Zinc supplementation attenuated ethanol-induced hepatic zinc depletion and liver injury as measured by histopathological and ultrastructural changes, serum alanine transferase activity, and hepatic tumor necrosis factor-? in both metallothionein-knockout and wild-type mice, indicating a metallothionein-independent zinc protection. Zinc supplementation inhibited accumulation of reactive oxygen species, as indicated by dihydroethidium fluorescence, and the consequent oxidative damage, as assessed by immunohistochemical detection of 4-hydroxynonenal and nitrotyrosine and quantitative analysis of malondialdehyde and protein carbonyl in the liver. Zinc supplementation suppressed ethanol-elevated cytochrome P450 2E1 activity but increased the activity of alcohol dehydrogenase in the liver, without affecting the rate of blood ethanol elimination. Zinc supplementation also prevented ethanol-induced decreases in glutathione concentration and glutathione peroxidase activity and increased glutathione reductase activity in the liver. In conclusion, zinc supplementation prevents alcoholic liver injury in an metallothionein-independent manner by inhibiting the generation of reactive oxygen species (P450 2E1) and enhancing the activity of antioxidant pathways.

Zhou, Zhanxiang; Wang, Lipeng; Song, Zhenyuan; Saari, Jack T.; McClain, Craig J.; Kang, Y. James

2005-01-01

276

Transport of Zinc Oxide Nanoparticles in a Simulated Gastric Environment  

NASA Astrophysics Data System (ADS)

Recent years have seen a growing interest in the use of many types of nano sized materials in the consumer sector. Potential uses include encapsulation of nutrients, providing antimicrobial activity, altering texture, or changing bioavailability of nutrients. Engineered nanoparticles (ENP) possess properties that are different than larger particles made of the same constituents. Properties such as solubility, aggregation state, and toxicity can all be changed as a function of size. The gastric environment is an important area for study of engineered nanoparticles because of the varied physical, chemical, and enzymatic processes that are prevalent there. These all have the potential to alter those properties of ENP that make them different from their bulk counterparts. The Human Gastric Simulator (HGS) is an advanced in vitro model that can be used to study many facets of digestion. The HGS consists of a plastic lining that acts as the stomach cavity with two sets of U-shaped arms on belts that provide the physical forces needed to replicate peristalsis. Altering the position of the arms or changing the speed of the motor which powers them allows one to tightly hone and replicate varied digestive conditions. Gastric juice, consisting of salts, enzymes, and acid levels which replicate physiological conditions, is introduced to the cavity at a controllable rate. The release of digested food from the lumen of simulated stomach is controlled by a peristaltic pump. The goal of the HGS is to accurately and repeatedly simulate human digestion. This study focused on introducing foods spiked with zinc oxide ENP and bulk zinc oxide into the HGS and then monitoring how the concentration of each changed at two locations in the HGS over a two hour period. The two locations chosen were the highest point in the lumen of the stomach, which represented the fundus, and a point just beyond the equivalent of the pylorus, which represented the antrum of the stomach. These points were chosen in order to elucidate if and how two different particle sizes of the same material are transported during digestion. Results showed that particles preferentially collected at Location A; time played a minor role in the separation to the two locations while particle size did not play any role.

Mayfield, Ryan T.

277

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

278

The role of intracellular zinc release in aging, oxidative stress, and Alzheimer's disease  

PubMed Central

Brain aging is marked by structural, chemical, and genetic changes leading to cognitive decline and impaired neural functioning. Further, aging itself is also a risk factor for a number of neurodegenerative disorders, most notably Alzheimer’s disease (AD). Many of the pathological changes associated with aging and aging-related disorders have been attributed in part to increased and unregulated production of reactive oxygen species (ROS) in the brain. ROS are produced as a physiological byproduct of various cellular processes, and are normally detoxified by enzymes and antioxidants to help maintain neuronal homeostasis. However, cellular injury can cause excessive ROS production, triggering a state of oxidative stress that can lead to neuronal cell death. ROS and intracellular zinc are intimately related, as ROS production can lead to oxidation of proteins that normally bind the metal, thereby causing the liberation of zinc in cytoplasmic compartments. Similarly, not only can zinc impair mitochondrial function, leading to excess ROS production, but it can also activate a variety of extra-mitochondrial ROS-generating signaling cascades. As such, numerous accounts of oxidative neuronal injury by ROS-producing sources appear to also require zinc. We suggest that zinc deregulation is a common, perhaps ubiquitous component of injurious oxidative processes in neurons. This review summarizes current findings on zinc dyshomeostasis-driven signaling cascades in oxidative stress and age-related neurodegeneration, with a focus on AD, in order to highlight the critical role of the intracellular liberation of the metal during oxidative neuronal injury.

McCord, Meghan C.; Aizenman, Elias

2014-01-01

279

Rapid isolation of a facultative anaerobic electrochemically active bacterium capable of oxidizing acetate for electrogenesis and azo dyes reduction.  

PubMed

In this study, 27 strains of electrochemically active bacteria (EAB) were rapidly isolated and their capabilities of extracellular electron transfer were identified using a photometric method based on WO3 nanoclusters. These strains caused color change of WO3 from white to blue in a 24-well agar plate within 40 h. Most of the isolated EAB strains belonged to the genera of Aeromonas and Shewanella. One isolate, Pantoea agglomerans S5-44, was identified as an EAB that can utilize acetate as the carbon source to produce electricity and reduce azo dyes under anaerobic conditions. The results confirmed the capability of P. agglomerans S5-44 for extracellular electron transfer. The isolation of this acetate-utilizing, facultative EBA reveals the metabolic diversity of environmental bacteria. Such strains have great potential for environmental applications, especially at interfaces of aerobic and anaerobic environments, where acetate is the main available carbon source. PMID:24648142

Shen, Nan; Yuan, Shi-Jie; Wu, Chao; Cheng, Yuan-Yuan; Song, Xiang-Ning; Li, Wen-Wei; Tong, Zhong-Hua; Yu, Han-Qing

2014-05-01

280

Gas Effect On Plasma Dynamics Of Laser Ablation Zinc Oxide  

SciTech Connect

In order to synthesis zinc oxide thin films and nanostructures, laser ablation of ZnO target into both vacuum and oxygen atmosphere was performed. The gas effect on the plume dynamics was studied for O{sub 2} pressures varied between 10{sup -2} to 70 mbar. Plasma plume evolution was investigated by ICCD camera fast imaging. The plasma was created by a KrF excimer laser ({lambda} = 248 nm, {tau} = 25 ns) at a fluence of 2 J/cm{sup 2}. The light emitted by the plume was observed along the perpendicular to the ejection direction through a fast intensified charge-coupled device (ICCD). We have found that the plasma dynamics is very affected by the gas pressures. The photographs reveal the stratification of plasma into slow and fast components for 0.5 mbar O{sub 2} pressures and beyond. The photographs also show the apparition of hydrodynamic instabilities which are related to chemical reactions between the plasma and the surrounding gas for a certain range of pressures.

Abdelli-Messaci, S.; Kerdja, T.; Lafane, S.; Malek, S. [Advanced Technology Development Center Haouch-Oukil, B. P. 17, Baba Hassen (Algeria)

2008-09-23

281

A transient electron transport analysis of bulk wurtzite zinc oxide  

NASA Astrophysics Data System (ADS)

A three-valley Monte Carlo simulation approach is used in order to probe the transient electron transport that occurs within bulk wurtzite zinc oxide. For the purposes of this analysis, we follow O'Leary et al. [Solid State Commun. 150, 2182 (2010)], and study how electrons, initially in thermal equilibrium, respond to the sudden application of a constant applied electric field. We find that for applied electric field strength selections in excess of 300 kV/cm that an overshoot in the electron drift velocity is observed. An undershoot in the electron drift velocity is also observed for applied electric field strength selections in excess of 700 kV/cm, this velocity undershoot not being observed for other compound semiconductors, such as gallium arsenide and gallium nitride. We employ a means of rendering transparent the electron drift velocity enhancement offered by the transient electron transport, and then use the calculated dependence of the peak transient electron drift velocity on the applied electric field for the design optimization of short-channel high-frequency electron devices.

Hadi, Walid A.; Shur, Michael S.; O'Leary, Stephen K.

2012-08-01

282

Cluster generation under pulsed laser ablation of zinc oxide  

NASA Astrophysics Data System (ADS)

Neutral and cationic Zn n O m clusters of various stoichiometry have been produced by nanosecond laser ablation of ZnO in vacuum and investigated by time-of-flight mass spectrometry. Particular attention was paid to the effect of laser wavelength (in the range from near-IR to UV) on cluster composition. Under 193-nm laser ablation, the charged clusters are essentially substoichiometric with ZnnO_{n-1}+ and ZnnO_{n-3}+ being the most abundant series. Both sub- and stoichiometric cationic clusters are generated in abundance at 532- and 1064-nm ablation whose composition depends on the cluster size. The reactivity of small stoichiometric ZnnOn+ clusters ( n<11) toward hydrogen is found to be high, while oxygen-deficient species are less reactive. The neutral plume particles are mainly stoichiometric with Zn4O4 tetramer being a magic cluster. It is suggested that the Zn4O4 loss is the dominant fragmentation channel of large zinc oxide clusters upon electron impact. Plume expansion conditions under ZnO ablation with visible and IR laser pulses are shown to be favorable for stoichiometric cluster formation.

Bulgakov, Alexander V.; Evtushenko, Anton B.; Shukhov, Yuri G.; Ozerov, Igor; Marine, Wladimir

2010-12-01

283

Fabrication and Electrical Characterization of Zinc Oxide Nanowires  

NASA Astrophysics Data System (ADS)

One dimensional semiconducting zinc oxide (ZnO) nanowires have drawn attractive attentions in the past years. The unique electrical, optical, and piezoelectric properties of ZnO nanowires make them broaden applications ranging from light emitting diode and lasers, solar cells, photodetectors, electron transporters and transistors, to piezoelectric generators. In our research, two-terminal current-voltage (I-V) measurements were conducted to determine the electrical conductivity alternation of the ZnO nanowires under laser irradiation, and various gaseous surroundings. The I-V curves at the temperature ranged from 150 to 300 K were recorded in vacuum. The Arrhenius plot shows perfect linear relation between I and 1/T. The donor lever of the semiconducting nanowire is about 326 meV. We observed that the current increased 50% with laser on in comparison to that with it off; it raised by a factor of four under ambient reductive gas CO. In addition, the I-V behaviors were found to be reversible with those various environments. Further studies on the possible nano- devices such as optical switches and chemical sensors are undergoing.

Zhang, Daqing; Lee, Chun-Hong; Berven, Chris; Katkanant, Vanvilai

2009-03-01

284

Attachment of Quantum Dots on Zinc Oxide Nanorods  

NASA Astrophysics Data System (ADS)

ZnO nanorods grown by hydrothermal technique are of great interest for potential applications in photovoltaic and optoelectronic devices. In this study we investigate the optimization of the optical absorption properties by a low temperature, chemical bath deposition technique. Our group fabricated nanorods on indium tin oxide (ITO) substrate with precursor solution of zinc nitrate hexahydrate and hexamethylenetramine (1:1 molar ratio) at 95C for 9 hours. In order to optimize the light absorption characteristics of ZnO nanorods, CdSe/ZnS core-shell quantum dots (QDs) of various diameters were attached to the surface of ZnO nanostructures grown on ITO and gold-coated silicon substrates. Density of quantum dots was varied by controlling the number drops on the surface of the ZnO nanorods. For a 0.1 M concentration of QDs of 10 nm diameter, the PL intensity at 385 nm increased as the density of the quantum dots on ZnO nanostructures was increased. For quantum dots at 1 M concentration, the PL intensity at 385 nm increased at the beginning and then decreased at higher density. We will discuss the observed changes in PL intensity with QD concentration with ZnO-QD band structure and recombination-diffusion processes taking place at the interface.

Seay, Jared; Liang, Huan; Harikumar, Parameswar

2011-03-01

285

Highly Conducting Transparent Indium-Doped Zinc Oxide Thin Films  

NASA Astrophysics Data System (ADS)

Highly conducting transparent indium-doped zinc oxide (IZO) thin films have been achieved by controlling different growth parameters using radio frequency magnetron sputtering. The structural, electrical, and optical properties of the IZO thin films have been investigated for varied indium content and growth temperature (T G) in order to find out the optimum level of doping to achieve the highest conducting transparent IZO thin films. The highest mobility and carrier concentration of 11.5 cm2/V-s and 3.26 × 1020 cm-3, respectively, have been achieved in IZO doped with 2% indium. It has been shown that as T G of the 2% IZO thin films increase, more and more indium atoms are substituted into Zn sites leading to shift in (002) peaks towards higher angles which correspond to releasing the stress within the IZO thin film. The minimum resistivity of 5.3 × 10-4 ?-cm has been achieved in 2% indium-doped IZO grown at 700°C.

Singh, Budhi; Ghosh, Subhasis

2014-06-01

286

Epitaxial Zinc Oxide Semiconductor Film deposited on Gallium Nitride Substrate  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) is a wide bandgap semiconductor which is very promising for making efficient electronic and optical devices. The goal of this research was to produce high quality ZnO film on gallium nitride (GaN) substrate by optimizing the substrate temperature. The GaN substrates were chemically cleaned and mounted on a ceramic heater and loaded into a vacuum deposition chamber that was pumped down to a base pressure of 3 x 10-7 Torr. The film deposition was preceded by a 30 minute thermal desorption carried in vacuum at 500 ^oC. The ZnO thin film was then sputter-deposited using an O2/Ar gas mixture onto GaN substrates heated at temperatures varying from 20 ^oC to 500 ^oC. Post-deposition annealing was done in a rapid thermal processor at 900 ^oC for 5 min in an ultrapure N2 ambient to improve the crystal quality of the films. The films were then optically characterized using photoluminescence (PL) measurement with a UV laser excitation. Our measurements reveal that ZnO films deposited on GaN substrate held at 200 ^oC gave the best film with the highest luminous intensity, with a peak energy of 3.28 eV and a full width half maximum of 87.4 nm. Results from low temperature (10 K) PL measurements and from x-ray diffraction will also be presented.

McMaster, Michael; Oder, Tom

2011-04-01

287

Zinc release from atomic layer deposited zinc oxide thin films and its antibacterial effect on Escherichia coli  

NASA Astrophysics Data System (ADS)

Zinc oxide films have been grown by atomic layer deposition (ALD) at different reaction temperatures and in various thicknesses. Zinc-ion release has been examined from the ZnO films in water and in phosphate buffered saline solution (PBS). Additionally, the antibacterial effect has been studied on Escherichia coli. The thickness of the ZnO film or its crystal orientation did not affect the rate of dissolution. ALD grown aluminum oxide films were deposited on top of the ZnO films and they acted as an effective barrier against zinc dissolution. The bacteriostatic effect was not dependent on the film thickness but both 45 nm and 280 nm thick ZnO films significantly reduced bacterial attachment and growth in dark conditions by 99.7% and 99.5%, respectively. The results indicated that photoirradiation is not required for to enhance antibacterial properties of inorganic films and that the elution of zinc ions is probably responsible for the antibacterial properties of the ZnO films. The duration of the antibacterial effect of ZnO can be controlled by accurate control of the film thickness, which is a feature of ALD, and the onset of the antibacterial effect can be delayed by a time which can be adjusted by controlling the thickness of the Al2O3 blocking layer. This gives the possibility of obtaining dual antibacterial release profiles through a nanolaminate structure of these two materials.

Kääriäinen, M.-L.; Weiss, C. K.; Ritz, S.; Pütz, S.; Cameron, D. C.; Mailänder, V.; Landfester, K.

2013-12-01

288

Zinc-oxide charge trapping memory cell with ultra-thin chromium-oxide trapping layer  

SciTech Connect

A functional zinc-oxide based SONOS memory cell with ultra-thin chromium oxide trapping layer was fabricated. A 5 nm CrO{sub 2} layer is deposited between Atomic Layer Deposition (ALD) steps. A threshold voltage (V{sub t}) shift of 2.6V was achieved with a 10V programming voltage. Also for a 2V V{sub t} shift, the memory with CrO{sub 2} layer has a low programming voltage of 7.2V. Moreover, the deep trapping levels in CrO{sub 2} layer allows for additional scaling of the tunnel oxide due to an increase in the retention time. In addition, the structure was simulated using Physics Based TCAD. The results of the simulation fit very well with the experimental results providing an understanding of the charge trapping and tunneling physics.

El-Atab, Nazek; Rizk, Ayman; Nayfeh, Ammar [Institute Center for Microsystems – iMicro, Department of Electrical Engineering and Computer Science (EECS), Masdar Institute of Science and Technology Abu Dhabi (United Arab Emirates)] [Institute Center for Microsystems – iMicro, Department of Electrical Engineering and Computer Science (EECS), Masdar Institute of Science and Technology Abu Dhabi (United Arab Emirates); Okyay, Ali K. [Department of Electrical and Electronics Engineering, Bilkent University, 06800 Ankara (Turkey) [Department of Electrical and Electronics Engineering, Bilkent University, 06800 Ankara (Turkey); UNAM-National Nanotechnology Research Center and Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara (Turkey)

2013-11-15

289

Zinc-oxide charge trapping memory cell with ultra-thin chromium-oxide trapping layer  

NASA Astrophysics Data System (ADS)

A functional zinc-oxide based SONOS memory cell with ultra-thin chromium oxide trapping layer was fabricated. A 5 nm CrO2 layer is deposited between Atomic Layer Deposition (ALD) steps. A threshold voltage (Vt) shift of 2.6V was achieved with a 10V programming voltage. Also for a 2V Vt shift, the memory with CrO2 layer has a low programming voltage of 7.2V. Moreover, the deep trapping levels in CrO2 layer allows for additional scaling of the tunnel oxide due to an increase in the retention time. In addition, the structure was simulated using Physics Based TCAD. The results of the simulation fit very well with the experimental results providing an understanding of the charge trapping and tunneling physics.

El-Atab, Nazek; Rizk, Ayman; Okyay, Ali K.; Nayfeh, Ammar

2013-11-01

290

Zinc oxide synergistic systems for the weathering stabilization of polyolefin encapsulants  

SciTech Connect

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), zinc dialkyldithiocarbamates (Methyl and Ethyl Zimate) and nickel-based UV stabilizers (Cyasorb 1084 and Ferro AM 105). One such system stabilizes the ethylene/vinyl acetate copolymer used as the encapsulant between the silicon and the substrate in flate-plate photovoltaic modules. Such modules have performed satisfactorily for over three years at the Jet Propulsion Laboratory site in sourthern California.

Baum, B.; Carr, D.S.

1983-05-01

291

Prevention of retinal light damage by zinc oxide combined with rosemary extract  

PubMed Central

Purpose Zinc oxide effectively reduces visual cell loss in rats exposed to intense visible light and is known to slow the rate of disease progression in advanced stages of age-related macular degeneration. Our goal was to determine the efficacy of zinc oxide in combination with novel and well-established antioxidants in an animal model of light-induced oxidative retinal damage. Methods One group of male Sprague-Dawley rats was pretreated with zinc oxide with or without a detergent extract of rosemary powder and then exposed to intense visible light for 4–24 h. Another group of animals received zinc oxide combined with rosemary oil diluted with a mixture of polyunsaturated fatty acids (ROPUFA) and a third group was given an antioxidant mineral mix containing zinc oxide, as recommended by the Age Related Eye Disease Study group's first clinical trial (AREDS1). Visual cell survival was determined 2 weeks after intense light treatment by measuring rhodopsin and photoreceptor cell DNA levels and confirmed by retinal histology and agarose gel electrophoresis of DNA. Western analysis was used to determine the effects of zinc and antioxidants on the oxidative stress markers, glial fibrillary acidic protein (GFAP), heme-oxygenase-1 (HO-1), and carboxyethylpyrrole (CEP). Rod and cone opsin and arrestin levels were used as markers of photoreceptor cell function. Results Dark-reared rats treated with 1.3 mg/kg zinc oxide and 17 mg/kg rosemary extract, or with one-half those doses, and exposed to moderate intensity green light retained 75%–85% of the rhodopsin and retinal DNA measured in unexposed rats. These levels were significantly higher than found for zinc oxide or rosemary treatment alone. Rosemary oil was also effective when combined with zinc oxide, but ROPUFA alone was no more effective than the detergent vehicle. Prolonged intense green light led to increases in retinal GFAP and HO-1 levels and to decreases in cone cell opsin and rod and cone arrestins. Rosemary plus zinc treatment reduced the expression of oxidative stress protein markers and enhanced visual cell survival, as shown by improved photoreceptor cell morphology and by decreased retinal DNA degradation. Using higher intensity white light for exposures in cyclic light-reared rats, treatment with an AREDS antioxidant/mineral mixture was found to be ineffective, whereas rosemary extract plus an equivalent dose of zinc oxide was significantly more effective in preserving visual cells. CEP protein adduct formation was reduced by all antioxidant treatments, but rosemary plus zinc oxide also prevented the loss of cone cell opsin and arrestin more effectively than AREDS. Conclusions In the rat model of acute retinal light damage, zinc oxide combined with a detergent extract of rosemary powder or rosemary oil is more effective than treatment with either component alone and significantly more effective than an AREDS mixture containing a comparable dose of zinc oxide. Light-induced oxidative stress in animal models of retinal degeneration can be a useful preclinical paradigm for screening novel antioxidants and for testing potential therapeutics designed to slow the progression of age-related ocular disease.

Darrow, R. M.; Rapp, C. M.; Smuts, J.P.; Armstrong, D.W.; Lang, J. C.

2013-01-01

292

Device performances of organic light-emitting diodes with indium tin oxide, gallium zinc oxide, and indium zinc tin oxide anodes deposited at room temperature.  

PubMed

Thin films of Indium tin oxide (ITO), Gallium zinc oxide (GZO), and Indium zinc tin oxide (IZTO) were deposited on glass substrates by pulsed direct current magnetron sputtering at room temperature. The structural, optical, and electrical properties of the films were investigated towards evaluating their applications as flexible anodes. IZTO films exhibited the lowest resistivity (6.3 x 10(-4) Omega cm). Organic light-emitting diodes (OLEDs) were fabricated using the ITO, GZO, and IZTO films as anode layers. The turn-on voltages at a current density of 4.5 mA/cm2, 5.5 mA/cm2, 6.5 mA/cm2 were 5.5 V, 13.7 V, and 4.7 V for the devices with ITO, GZO, and IZTO anodes, respectively. The best performance was observed with the IZTO film, indicating its suitability as an alternative material for conventional ITO anodes used in OLEDs and flexible displays. PMID:24266182

Lee, Changhun; Ko, Yoonduk; Kim, Youngsung

2013-12-01

293

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

294

Chemical Carcinogenesis: Azo Dyes, Aryl Amines, and Related Compounds.  

National Technical Information Service (NTIS)

This agent-oriented Cancergram deals with carcinogenicity of fluorene derivatives, azo compounds, naphthylamines, nitroguinoline oxides, and other related specific substances (including hair dyes). The scope includes carcinogenicity and modification of ca...

1982-01-01

295

Dual signal amplification of zinc oxide nanoparticles and quantum dots-functionalized zinc oxide nanoparticles for highly sensitive electrochemiluminescence immunosensing.  

PubMed

A novel electrochemiluminescence (ECL) immunosensor for highly sensitive detection of ?-fetoprotein (AFP) based on a dual signal amplification strategy was developed. Zinc oxide (ZnO) nanoparticles were employed as the carriers for immobilizing the capture AFP antibody (Ab1) and CdSe quantum dots (QDs). CdSe QDs-functionalized ZnO nanoparticles were used as the tracer to label the signal AFP antibody (Ab2). CdSe QDs-functionalized ZnO nanoparticles were prepared through an amide dehydration reaction and they were characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. The Ab2 was bound to the CdSe QDs-functionalized ZnO nanoparticles to obtain the detection probe. ZnO nanoparticles could accelerate electron transfer between the detection probe and the electrode, and their large surface area was beneficial for loading more CdSe QDs, leading to an enhanced ECL signal (0.9-fold increase) by a sandwich immunoreaction. This also indicated efficient association of the detection probe on the immunosensor surface. The designed immunoassay showed a wide linear range from 0.5 to 600 ng mL(-1) with a detection limit of 0.48 ng mL(-1) at a S/N ratio of 3 for AFP detection. The ECL immunosensor exhibited good analytical performance and was successfully applied to clinical sample detection, showing a promising application in ECL biosensing. PMID:23882462

Zhang, Jinxing; Liu, Suli; Bao, Jianchun; Tu, Wenwen; Dai, Zhihui

2013-09-21

296

Silver Oxide/Zinc Rechargeable Lithium Cells: A Comparison with High Energy Density Lithium/Lithium Cobalt Oxide.  

National Technical Information Service (NTIS)

Commercial, 30-ampere-hour Silver Oxide/Zinc (AgO/Zn) cells were evaluated for cycle life and charge retention. Results were compared to recently developed 30-ampere-hour Lithium/Lithium Cobalt Oxide (Li/Li(x)CoO2) cells. Prior to cycling at -2 deg C, +23...

H. P. W. Lin C. J. Kelly D. L. Chua C. W. Fleischmann P. H. Smith

1995-01-01

297

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

298

Efficient decolorization of azo dye Reactive Black B involving aromatic fragment degradation in buffered Co2+/PMS oxidative processes with a ppb level dosage of Co2+-catalyst.  

PubMed

In order to generate powerful radicals as oxidizing species for the complete decolorization and degradation of azo dye Reactive Black B (RBB) at near neutral pH (pH 6), homogeneous activation of peroxymonosulfate (Oxone: PMS) by the trace Co2+-catalysts was explored. We not only took advantage of the high oxidation-reduction potential of produced hydroxyl and sulfite radicals but also an opportunity to oxidize RBB to less complex compounds with extremely low dosages, especially the ppb level of the Co2+-catalyst (stoichiometric ratio: [Co2+](0)/[RBB](0)=1.7 x 10(-6)-1.7 x 10(-5); [PMS](0)/[RBB](0)=8-32). Anion effects and pH effects were also carried out and discussed to simulate an actual application such as that of a textile waste stream. Both the degradations of RBB and its derivative aromatic fragments were illustrated successfully at UV-visable absorptions of 591 and 310 nm, respectively, and the possible relationships between them were also proposed and discussed, based on the experimental results. The RBB degradation in this Co2+/PMS oxidative process successfully formulated a pseudo-first-order kinetic model at an isothermal condition of 25 degrees C with or without different anions present. The initial rate and rate constant were calculated under different comparative conditions, and the results indicate that the activity of both RBB decolorization and its degradation are not obviously dependent on the PMS concentration, but rather are related to the Co2+ dosage. PMID:19541412

Huang, Yao-Hui; Huang, Yi-Fong; Huang, Chun-Ing; Chen, Chuh-Yung

2009-10-30

299

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

300

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

301

Optical characterization of gallium nitride and zinc oxide  

NASA Astrophysics Data System (ADS)

The optical properties of Gallium Nitride (GaN) and Zinc Oxide (ZnO) were studied through transmission spectroscopy and photoluminescence. The use of very thin films of less than 0.5 ?m on a transparent sapphire substrate permitted the direct observation of excitons at room temperature and 77 K in both materials. The films used were thin enough that the absorption coefficient was accurately determined above the band gap. The excitonic structure observed was fit with an excitonic model of absorption determining the exciton binding energy, band gaps and valence band splittings. In the case of gallium nitride the recombination constant was also determined. In photoluminescence studies of a bulk single crystal ZnO, line narrowing and modal development was observed indicative of stimulated emission and lasing. The photoluminescence of ZnO nanoparticles was also studied and found to be comparable to the luminescence of single crystal ZnO. Single crystal epitaxial ZnO thin films were deposited by pulsed laser deposition. The as-deposited films were of high quality, but it was found that annealing the films in oxygen could remove the point defects improving the films further. The improvement in the films was quantified through observation of the excitonic structure. It was also found that annealing improved band edge luminescence significantly and reduced defect luminescence. In photoluminescence studies of polycrystalline ZnO films deposited by sputtering on quartz substrates, it was found that ultraviolet laser light can be used to anneal the ZnO. The unannealed portions of the sample did not emit light while the annealed portions emitted light efficiently. Changes in the film morphology were also observed.

Muth, John Franklyn

1998-09-01

302

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

2011-11-01

303

Impacts of humidity and temperature on the performance of transparent conducting zinc oxide.  

SciTech Connect

The impact of humidity and temperature on a zinc oxide based transparent conducting oxide (TCO) was assessed under accelerated aging conditions. An in situ electroanalytical method was used to monitor the electrical properties for a conducting zinc oxide under controlled atmospheric (humidity, temperature and irradiation) conditions. A review of thin film photovoltaic (PV) literature has shown one major failure mode of cells/modules is associated with the ingress of water into modules in the field. Water contamination has been shown to degrade the performance of the TCO in addition to corroding interconnects and other conductive metals/materials associated with the module. Water ingress is particularly problematic in flexible thin film PV modules since traditional encapsulates such as poly(ethyl vinyl acetate) (EVA) have high water vapor transmission rates. The accelerated aging studies of the zinc oxide based TCOs will allow acceleration factors and kinetic parameters to be determined for reliability purposes.

Granata, Jennifer E.; Yaklin, Melissa A.; Schneider, Duane Allen; Staiger, Chad Lynn; Norman, Kirsten

2010-06-01

304

Feeding Low or Pharmacological Concentrations of Zinc Oxide Changes the Hepatic Proteome Profiles in Weaned Piglets  

PubMed Central

Pharmacological levels of zinc oxide can promote growth and health of weaning piglets, but the underlying molecular mechanisms are yet not fully understood. The aim of this study was to determine changes in the global hepatic protein expression in response to dietary zinc oxide in weaned piglets. Nine half-sib piglets were allocated to three dietary zinc treatment groups (50, 150, 2500 mg/kg dry matter). After 14 d, pigs were euthanized and liver samples taken. The increase in hepatic zinc concentration following dietary supplementation of zinc was accompanied by up-regulation of metallothionein mRNA and protein expression. Global hepatic protein profiles were obtained by two-dimensional difference gel electrophoresis following matrix-assisted laser desorption ionization/time-of-flight mass spectrometry. A total of 15 proteins were differentially (P<0.05) expressed between groups receiving control (150 mg/kg) or pharmacological levels of zinc (2500 mg/kg) with 7 down- (e.g. arginase1, thiosulfate sulfurtransferase, HSP70) and 8 up-regulated (e.g. apolipoprotein AI, transferrin, C1-tetrahydrofolate synthase) proteins. Additionally, three proteins were differentially expressed with low zinc supply (50 mg/kg Zn) in comparison to the control diet. The identified proteins were mainly associated with functions related to cellular stress, transport, metabolism, and signal transduction. The differential regulation was evaluated at the mRNA level and a subset of three proteins of different functional groups was selected for confirmation by western blotting. The results of this proteomic study suggest that zinc affects important liver functions such as blood protein secretion, protein metabolism, detoxification and redox homeostasis, thus supporting the hypothesis of intermediary effects of pharmacological levels of zinc oxide fed to pigs.

Bondzio, Angelika; Pieper, Robert; Gabler, Christoph; Weise, Christoph; Schulze, Petra; Zentek, Juergen; Einspanier, Ralf

2013-01-01

305

Magnesium-doped zinc oxide electrochemically grown on fluorine-doped tin oxide substrate.  

PubMed

Nanostructures of magnesium (Mg) doped Zinc oxide (ZnO) were successfully deposited on conducting fluorine-doped tin oxide (FTO) coated glass plates by cathodic electrochemical deposition method at different potentials and temperature conditions. The deposited samples were characterized by XRD and SEM techniques to confirm their structures, morphologies and optical properties. These measurements show that Mg doped ZnO has a wurtzite structure and that the strongest intensity of the (002) peak is found at 60 degrees C and -1.0 V. Tunable transmittance of Mg doped ZnO has a band gap energy from 3.45 eV to 3.82 eV, which is the direct evidence of doping. PMID:22849195

Han, Q F; Jeong, Y I; Heo, J H; Shin, C M; Ryu, H; Park, M S; Lee, W J; Yoon, J H; Yang, J E; Choi, H

2012-04-01

306

Manganese doped Zinc oxide thin film hydrogen gas sensor at reduced operating temperature  

Microsoft Academic Search

During the pas t few decades, semiconductor metal oxide (SMO) gas sensors have become a prime technology in several domestic, commercial, and industrial gas sensing. The semiconductor properties of zinc oxide along with its dopant remain to be trapped fully in its application as gas sensor. With the advent of nanotechnology, miniaturization and high sensitivity happens to be a key

Anjali Chatterjee; Partha Bhattacharjee; P. kumbakar; Nirmal Kumar Roy

2011-01-01

307

Materials Science Cements Containing Syringic Acid Esters- o-Ethoxybenzoic Acid and Zinc Oxide  

Microsoft Academic Search

Fissure caries is reduced when syringic acid is incorporated into a cariogenic diet of rats. It was therefore of interest to synthesize n-hexyl and 2-ethylhexyl syringate and to evaluate the properties of cements with these compounds as ingredients. Liquids containing the esters dissolved in o-ethoxybenzoic acid (EBA) - when mixed with powders made up from zinc oxide, aluminum oxide, and

G. M. Brauer; J. W. Stansbury

1984-01-01

308

Indium-doped zinc oxide thin films deposited by chemical spray starting from zinc acetylacetonate: effect of the alcohol and substrate temperature  

Microsoft Academic Search

Highly conductive and transparent indium-doped zinc oxide thin films were deposited by the chemical spray technique on sodocalcic glass substrates starting from zinc acetylacetonate. The role of the type of alcohols, namely, methanol, ethanol and isopropyl and the substrate temperature on the electrical, structural, surface morphology and optical characteristics of the thin films were studied. The results show that some

A. Maldonado; M. de la Luz Olvera; S. Tirado Guerra; R. Asomoza

2004-01-01

309

Antibacterial properties of composite resins incorporating silver and zinc oxide nanoparticles on Streptococcus mutans and Lactobacillus  

PubMed Central

Objectives Recurrent caries was partly ascribed to lack of antibacterial properties in composite resin. Silver and zinc nanoparticles are considered to be broad-spectrum antibacterial agents. The aim of the present study was to evaluate the antibacterial properties of composite resins containing 1% silver and zinc-oxide nanoparticles on Streptococcus mutans and Lactobacillus. Materials and Methods Ninety discoid tablets containing 0%, 1% nano-silver and 1% nano zinc-oxide particles were prepared from flowable composite resin (n = 30). The antibacterial properties of composite resin discs were evaluated by direct contact test. Diluted solutions of Streptococcus mutans (PTCC 1683) and Lactobacillus (PTCC 1643) were prepared. 0.01 mL of each bacterial species was separately placed on the discs. The discs were transferred to liquid culture media and were incubated at 37? for 8 hr. 0.01 mL of each solution was cultured on blood agar and the colonies were counted. Data was analyzed with Kruskall-Wallis and Mann-Whitney U tests. Results Composites containing nano zinc-oxide particles or silver nanoparticles exhibited higher antibacterial activity against Streptococcus mutans and Lactobacillus compared to the control group (p < 0.05). The effect of zinc-oxide on Streptococcus mutans was significantly higher than that of silver (p < 0.05). There were no significant differences in the antibacterial activity against Lactobacillus between composites containing silver nanoparticles and those containing zinc-oxide nanoparticles. Conclusions Composite resins containing silver or zinc-oxide nanoparticles exhibited antibacterial activity against Streptococcus mutans and Lactobacillus.

Kasraei, Shahin; Sami, Lida; Hendi, Sareh; AliKhani, Mohammad-Yousef; Rezaei-Soufi, Loghman

2014-01-01

310

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

PubMed

An imbalance in the systemic redox status leading to oxidative stress has been an important factor in development of senile cataracts, which is reflected by an increase in serum TBARS and a decrease in plasma SOD activity. Zinc has been an important cofactor required for structural stability of SOD. In the present study the role of serum zinc level and plasma SOD activity was analyzed in senile cataract patients showing significant oxidative stress. Serum TBARS, plasma SOD and serum zinc level was measured in thirty randomly selected senile cataract patients against properly matched controls. Although, the analysis of means showed a significant increase in serum TBARS and decrease in plasma SOD and serum zinc level in cases, but plasma SOD was found to be just significantly correlated (p=0.05) with the serum zinc only in the cases. The results of partial correlation studies and multiple regression analysis, also, showed only a significant correlation and predictable dependence between serum TBARS and plasma SOD, excluding any role of serum zinc level. The present study concludes that it is chiefly the plasma SOD activity, but not the serum zinc level, that determines the proneness of the patients for development of senile cataract. PMID:23105695

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

2007-09-01

311

Morphological, optical, and nonlinear optical properties of fluorine-indium-doped zinc oxide thin films  

Microsoft Academic Search

Chemically sprayed fluorine-indium-doped zinc oxide thin films (ZnO:F:In) were deposited on glass substrates. A mixture of zinc pentanedionate, indium sulfate, and fluoride acid was used in the starting solution. The influence of both the dopant concentration in the starting solution and the substrate temperature on the transport, morphological, linear, and nonlinear optical (NLO) properties were fully characterized with atomic force

O. G. Morales-Saavedra; L. Castañeda; J. G. Bañuelos; R. Ortega-Martínez

2008-01-01

312

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

313

Morphological, optical, and nonlinear optical properties of fluorine-indium-doped zinc oxide thin films  

Microsoft Academic Search

Chemically sprayed fluorine-indium-doped zinc oxide thin films (ZnO:F:In) were deposited on glass substrates. A mixture of\\u000a zinc pentanedionate, indium sulfate, and fluoride acid was used in the starting solution. The influence of both the dopant\\u000a concentration in the starting solution and the substrate temperature on the transport, morphological, linear, and nonlinear\\u000a optical (NLO) properties were fully characterized with atomic force

O. G. Morales-Saavedra; L. Castañeda; J. G. Bañuelos; R. Ortega-Martínez

2008-01-01

314

Improved mobility and conductivity of an Al2O3 incorporated indium zinc oxide system  

Microsoft Academic Search

The investigation of Al2O3 doped indium zinc oxide (83 cation % In-17 cation % Zn), denoted Al2O3-IZO, shows that the conductivity of certain amorphous Al2O3-IZO samples can be 752 S cm-1 with a mobility of 26.5 cm2V-1s-1, 4 times higher than that of IZO (190 Scm-1) with an industrial standard indium and zinc atomic ratio of 83\\/17. Furthermore, by increasing

Jian Sun; Yanhua Huang; Hao Gong

2011-01-01

315

Effect of Zinc Deficiency on Memory, Oxidative Stress and Blood Chemistry in Rats  

Microsoft Academic Search

The effect of zinc deficiency on memory function, oxidative stress and blood chemistry in rats was investigated .Forty-two male (65.0±2.78g) albino Sprague Dawley rats were equally divided into three groups 4 A. B and C. Two experimental diets were formulated, consisting of 4mg ZnSO \\/kg as zinc deficient diet and 4 4 30mg ZnSO \\/kg , as Zn adequate diet.

Osaretin A. T. Ebuehi; Gabriel A. Akande

316

Influence of pH on the transport of nanoscale zinc oxide in saturated porous media  

Microsoft Academic Search

Widespread use of nanoscale zinc oxide (nZnO) in various fields causes subsurface environment contamination. Even though the\\u000a transport of dissolved zinc ions in subsurface environments such as soils and sediments has been widely studied, the transport\\u000a mechanism of nZnO in such environments is poorly understood. In addition, nZnO is often combined with stabilizers or dispersing\\u000a agents to prevent its aggregation

Sushil R. Kanel; Souhail R. Al-Abed

317

Functional finishing of cotton fabrics using zinc oxide soluble starch nanocomposites  

Microsoft Academic Search

Zinc oxide-soluble starch nanocomposites (nano-ZnO) synthesized using water as a solvent and soluble starch as a stabilizer is impregnated onto cotton fabrics to impart antibacterial and UV-protection functions. Nano-ZnO synthesized by reacting zinc nitrate with sodium hydroxide in the presence of soluble starch absorbed strongly at 361 nm due to the quantum confinement effect. The average size of ZnO nanoparticles

Nadanathangam Vigneshwaran; Sampath Kumar; A. A. Kathe; P. V. Varadarajan; Virendra Prasad

2006-01-01

318

Cadmium-induced testes oxidative damage in rats can be influenced by dietary zinc intake  

Microsoft Academic Search

We tested the hypothesis that zinc deficient animals would be characterized by an increased sensitivity to cadmium-induced oxidative damage to the testes. Weanling male rats were given free access to either a control (25 ?g Zn\\/g) or a zinc deficient (0.5 ?g Zn\\/g) diet; or restricted access to the 25 ?g Zn\\/g diet at a level of intake similar to

Patricia I. Oteiza; Viviana N. Adonaylo; Carl L. Keen

1999-01-01

319

Zinc oxide films prepared by sol-gel spin-coating  

Microsoft Academic Search

The d.c. electrical conductivity and optical properties of undoped zinc oxide films prepared by the sol-gel process using a spin-coating technique were investigated. The ZnO films were obtained by 10 cycle spin-coated and dried zinc acetate films followed by annealing in air at 500–575°C. The films deposited on the Pyrex glass substrate were polycrystalline and c-axis oriented. A minimum film

Y. Natsume; H Sakata

2000-01-01

320

Effect of cations and anions on properties of zinc oxide particles synthesized in supercritical water  

Microsoft Academic Search

Hydrothermal synthesis of zinc oxide fine particles from zinc salt (Zn(CH3COO)2, ZnSO4, Zn(NO3)2) and alkali metal hydroxide (LiOH, KOH) aqueous solution was carried out with a Ti alloy batch reactor in supercritical water. Particle size synthesized in LiOH solution was relatively smaller than that in KOH. Emission spectra of the particle produced from ZnSO4 and LiOH aqueous solution shows the

Kiwamu Sue; Kazuhito Kimura; Kenji Murata; Kunio Arai

2004-01-01

321

Enhanced performance of indium zinc oxide thin film transistor by yttrium doping  

NASA Astrophysics Data System (ADS)

The Y3+-doped indium zinc oxide thin film transistor devices were fabricated by the sol-gel spin-coating technique. The Y3+-doped indium zinc oxide thin film transistor operates in n-channel enhancement mode and exhibits a well-defined pinch-off and saturation region. Because yttrium ion possesses lower electronegativity (1.22) and standard electrode potential (-2.372 V), it can act as the carrier suppressor to reduce the carrier concentrations of indium zinc oxide (In:Zn = 1:1) thin films from 1.29 × 1020 to 3.05 × 1014 cm-3 with the increase of Y3+ doping concentrations from 0 to 12 mol%. In addition, Y3+ (12 mol%)-doped indium zinc oxide thin film has the minimal surface roughness (1.067 nm) and lowest trap states (5.14 × 1012 cm-2). Therefore, Y3+ (12 mol%)-doped indium zinc oxide thin film transistor possesses the optimum performance, and its field-effect mobility in the saturated regime, threshold voltage, on-off ratio, and S-factor are 4.76 cm2/Vs, 4.3 V, 1.32 × 106, and 2.9 V/decade, respectively.

Ting, Chu-Chi; Chang, Shiep-Ping; Li, Wei-Yang; Wang, Ching-Hua

2013-11-01

322

Antidiabetic Activity of Zinc Oxide and Silver Nanoparticles on Streptozotocin-Induced Diabetic Rats  

PubMed Central

The use of nanoparticles in medicine is an attractive proposition. In the present study, zinc oxide and silver nanoparticles were evaluated for their antidiabetic activity. Fifty male albino rats with weight 120 ± 20 and age 6 months were used. Animals were grouped as follows: control; did not receive any type of treatment, diabetic; received a single intraperitoneal dose of streptozotocin (100 mg/kg), diabetic + zinc oxide nanoparticles (ZnONPs), received single daily oral dose of 10 mg/kg ZnONPs in suspension, diabetic + silver nanoparticles (SNPs); received a single daily oral dose of SNP of 10 mg/kg in suspension and diabetic + insulin; received a single subcutaneous dose of 0.6 units/50 g body weight. Zinc oxide and silver nanoparticles induce a significant reduced blood glucose, higher serum insulin, higher glucokinase activity higher expression level of insulin, insulin receptor, GLUT-2 and glucokinase genes in diabetic rats treated with zinc oxide, silver nanoparticles and insulin. In conclusion, zinc oxide and sliver nanoparticles act as potent antidiabetic agents.

Alkaladi, Ali; Abdelazim, Aaser Mohamed; Afifi, Mohamed

2014-01-01

323

Extracellular synthesis of zinc oxide nanoparticle using seaweeds of gulf of Mannar, India  

PubMed Central

Background The biosynthesis of metal nanoparticles by marine resources is thought to be clean, nontoxic, and environmentally acceptable “green procedures”. Marine ecosystems are very important for the overall health of both marine and terrestrial environments. The use of natural sources like Marine biological resources essential for nanotechnology. Seaweeds constitute one of the commercially important marine living renewable resources. Seaweeds such as green Caulerpa peltata, red Hypnea Valencia and brown Sargassum myriocystum were used for synthesis of Zinc oxide nanoparticles. Result The preliminary screening of physico-chemical parameters such as concentration of metals, concentration of seaweed extract, temperature, pH and reaction time revealed that one seaweed S. myriocystum were able to synthesize zinc oxide nanoparticles. It was confirmed through the, initial colour change of the reaction mixture and UV visible spectrophotometer. The extracellular biosynthesized clear zinc oxide nanoparticles size 36 nm through characterization technique such as DLS, AFM, SEM –EDX, TEM, XRD and FTIR. The biosynthesized ZnO nanoparticles are effective antibacterial agents against Gram-positive than the Gram-negative bacteria. Conclusion Based on the FTIR results, fucoidan water soluble pigments present in S. myriocystum leaf extract is responsible for reduction and stabilization of zinc oxide nanoparticles. by this approach are quite stable and no visible changes were observed even after 6 months. These soluble elements could have acted as both reduction and stabilizing agents preventing the aggregation of nanoparticles in solution, extracellular biological synthesis of zinc oxide nanoparticles of size 36 nm.

2013-01-01

324

Facile synthesis of zinc hydroxide carbonate flowers on zinc oxide nanorods with attractive luminescent and optochemical performance  

NASA Astrophysics Data System (ADS)

A simple synthesis route was designed to fabricate a functional composite, zinc hydroxide carbonate (ZHC) flowers on zinc oxide (ZnO) nanorods. The hydrolysis of hexamethylenetetramine (HMT) can generate various species which are slowly released and gradually change reaction modes in a Zn(NO3)2/HMT solution. As a result, ZnO nanorods and ZHC flowers can be sequentially synthesized and connect very well under constant experimental conditions. The obtained composite has the advantages of both components and exhibits attractive properties. For instance, ZHC flowers on ZnO nanorods exhibit strong blue emission under the excitation of ultraviolet light, and dye-sensitized solar cells with the annealed composite as photoanode achieve much higher conversion efficiency than pure nanorod arrays.

Mao, Jing; Li, Jia-Jun; Ling, Tao; Liu, Hui; Yang, Jing; Du, Xi-Wen

2011-06-01

325

Facile synthesis of zinc hydroxide carbonate flowers on zinc oxide nanorods with attractive luminescent and optochemical performance.  

PubMed

A simple synthesis route was designed to fabricate a functional composite, zinc hydroxide carbonate (ZHC) flowers on zinc oxide (ZnO) nanorods. The hydrolysis of hexamethylenetetramine (HMT) can generate various species which are slowly released and gradually change reaction modes in a Zn(NO(3))(2)/HMT solution. As a result, ZnO nanorods and ZHC flowers can be sequentially synthesized and connect very well under constant experimental conditions. The obtained composite has the advantages of both components and exhibits attractive properties. For instance, ZHC flowers on ZnO nanorods exhibit strong blue emission under the excitation of ultraviolet light, and dye-sensitized solar cells with the annealed composite as photoanode achieve much higher conversion efficiency than pure nanorod arrays. PMID:21543828

Mao, Jing; Li, Jia-Jun; Ling, Tao; Liu, Hui; Yang, Jing; Du, Xi-Wen

2011-06-17

326

Effect of zinc oxide doping on the structural and optical characterization of nanostructured molybdenum oxide films.  

PubMed

Undoped and zinc oxide (ZnO) doped molybdenum oxide (MoO3) films were prepared by RF magnetron sputtering technique. The influence of doping and post annealing temperature on the structural and optical properties of these films were investigated systematically using X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-VIS spectroscopy and photoluminescence spectroscopy (PL). The XRD patterns indicate the presence of stoichiometric orthorhombic alpha-MoO3 phase in the annealed (573 and 673 K) undoped molybdenum oxide films and in ZnO doped molybdenum oxide film (annealed at 673 K). The crystalline grain size in the films was investigated using Debye Scherrer formula and corrected using Hall-Williamson equation. The SEM and AFM images revealed the distribution of nano leafs, nanorods and nanograins. Nanorods of length 1.4 microm and diameter 149 nm can be observed in ZnO doped films. The optical band gap energy was found to increase with increase in annealing temperature and particle size. These nanostructures show a room temperature PL emission in the UV and visible region. PMID:19928209

Navas, I; Vinodkumar, R; Lethy, K J; Satyanarayana, M; Ganesan, V; Pillai, V P Mahadevan

2009-09-01

327

Biocidal effects of silver and zinc oxide nanoparticles on the bioluminescent bacteria  

NASA Astrophysics Data System (ADS)

The effect of silver and zinc oxide nanoparticles in combination with alginate on bioluminescent Photobacterium leiognathi Sh1 bacteria was investigated. Silver nanoparticles were found to be more toxic than zinc oxide nanoparticles on bioluminescent bacteria. The nanoparticles and their ions released results in the same effect, however, it was absent in combination with alginate. The effective inhibiting concentration (EC50) for silver nanoparticles was found about 0.3 - 0.4 ?g mL-1, which was up to two times larger then for zinc oxide nanoparticles. The absence of sodium chloride in the tested media prevented the formation of colloidal particles of larger size and the effective inhibition concentrations of metal derivatives were lower than in the presence of sodium chloride.

Taran, M. V.; Starodub, N. F.; Katsev, A. M.; Guidotti, M.; Khranovskyy, V. D.; Babanin, A. A.; Melnychuk, M. D.

2013-11-01

328

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

329

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

330

Defect Structures in Zinc\\/Tin Codoped Indium Oxide Transparent Conductors  

Microsoft Academic Search

Tin-doped indium oxide (ITO) and Zinc\\/Tin codoped indium oxide (ZITO) are transparent n-type conducting oxides (TCOs), widely used in such devices as solar panels, electro-active windows, flat panel and liquid crystal displays. The conducting properties of both materials are critically dependent on the defect chemistry. In contrast to ITO, comparatively little is known about the defect chemistry in ZITO. Here

Oliver Warschkow; Ljubomir Miljacic; Jason A. Sese; Thomas A. Mason; Donald E. Ellis

2003-01-01

331

Effect of the temperature on structural and optical properties of zinc oxide nanoparticles.  

PubMed

Zinc nitrate hexahydrate, Zn(NO3)2 x 6H2O was used as a precursor with urea NH2CONH2 to prepare hydrozincite Zn5(CO3)2(OH)6 powder using hydrothermal method for 8 h at 90 degrees C. Zinc oxide (ZnO) nanoparticles (NPs) were prepared by thermal annealing of hydrozincite powder at different annealing temperatures, i.e., 350, 550 750 and 950 degrees C in air for 2 h. The resulting materials were characterized by X-ray diffraction, scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). The optical properties of the products were characterized by Fourier transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy and photoluminescence (PL) spectra. It was found that the particle size increased from - 33 to 250 nm with increasing in the annealing temperatures. FTIR results showed that the standard peaks of zinc oxide were presented at 428.17 and 532.32 cm(-1). Thermal analysis study showed that the primary weight loss starts at - 93 degrees C is due to solvent evaporation. The secondary weight loss, observed at - 378 degrees C, is due to phase transition from hydrated zinc oxide to zinc oxide. The band gaps of the products were in the range - 3.26-3.30 eV. The PL spectrum showed that the as-synthesized ZnO nanoparticles had UV (381 nm) and green (537 nm) emissions. PMID:24758046

Hadia, N M A; García-Granda, Santiago; García, José R

2014-07-01

332

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

333

Synthesis, characterization and luminescence properties of zinc oxide nanostructures  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) represents an important semiconductor material due to its wideband gap (3.37 eV at room temperature), large exciton binding energy (60 meV), high optical gain, and luminescence as well as piezoelectric properties [1]. From the 1960s, ZnO thin films have been extensively studied because of their applications as sensors, transducers and catalysts [2]. Since a few decades, one-dimensional nanostructures have become the focus point in nanoscience and nanotechnology. Nanostructures are considered to have unique physical, chemical, catalytic and optical properties that are profoundly different from their bulk counterparts. Since the discovery of carbon nanotubes (CNTs) in 1991, a string of research activities led to the growth and characterization of nanostructures of various materials including semiconductors such as Si, Ge and also compound semiconductors such as InP, GaAs, GaN and ZnO. ZnO is a versatile material and has shown potential for the synthesis of various types of nanostructures such as nanocombs, nanorings, nanohelices/nanosprings, nanobelts, nanowires and nanocages under specific growth conditions and probably has the richest family of nanostructures among all materials, both in structure and properties. This dissertation presents the synthesis, characterization and luminescence properties of ZnO nanostructures with the development of a PVD system. The nanostructures of ZnO are synthesized on various kinds of substrates such as Silicon, Sapphire and Alumina. We have synthesized a large family of nanostructures such as nanowires, nanorods, nanobelts, aligned nanorods, nanosheets, nanospheres, nanocombs, microspheres, hexagons etc. The nanostructures are then characterized by SEM, EDX, TEM, HRTEM, XRD, Raman Spectroscopy, PL and CL. From the characterization of the materials, we observed that these nanostructures are of good crystalline quality. PL and CL spectra reveal that all the nanostructures emit a ˜380 nm (UV) usually called the near band edge emission and a broad green band related to the defects and surface states at about 500 nm. Ultra-fine nanowires/belts show band edge emission of about 367 nm, with a blue shift of 124 meV relative to the other structures (380 nm). This dissertation gives an overview of the optical properties of ZnO nanostructures, in addition to the issues such as controlled growth, band-gap engineering, synthesis and characterization of these nanostructures.

Khan, Aurangzeb

334

Evaluation for Application of Built-in Type Zinc Oxide Gapless Surge Arresters for Power System Equipments  

Microsoft Academic Search

This paper deals with the development and application of built-in type zinc oxide gapless surge arresters for power system equipments. Built-in type surge arresters developed by the authors have been in service within power equipments on power systems without any apparent problems. The technical problems for practical use, their solutions, and future applications of zinc oxide gapless surge arresters are

Y. Harumoto; Y. Tsuda; M. Kobayashi; M. Mizuno; T. Aoki

1987-01-01

335

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

336

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.

337

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

338

Electrochemical self-assembly of oriented zinc oxide film from polyethylene oxide containing electrolyte.  

PubMed

Oriented nanopillar ZnO crystals were firstly fabricated by the potentiostatic cathodic electrodeposition technique on conducting glass substrates from polyethylene oxide (PEO) containing zinc nitrate solutions at low temperature (343 K). The mechanism for PEO-assisted electrochemical growth of ZnO hexagonal columus was proposed and confirmed by scanning electron microscopy, X-ray diffraction and UV-visible spectrophotometer measurements. It was observed that the concentration of PEO played an important role in the morphology and size of ZnO crystals. The structure and optical studies indicated that the addition of PEO not only influenced crystal growth habit but also improve the optical properties of ZnO. PMID:19435038

Ju, Xiaohui; Feng, Wei; Fujii, Akihiko; Ozaki, Masanori

2009-03-01

339

Inhibition of human pulpal gelatinases (MMP-2 and MMP-9) by zinc oxide cements.  

PubMed

The interaction between metal ions and the oral environment is a major subject matter in dental research. Matrix metalloproteinases (MMPs) have been implicated in several pathological and physiological processes such as, periodontal tissue destruction, root caries, dentin calcification and pulpal inflammation. The aim of this work was to test the effect of zinc released from zinc oxide-eugenol (ZOE) cements, on the activity of the major pulpal gelatinolytic MMPs. Pulpal explants were cultured overnight in Dulbecco's Modified Eagle Medium and the activity of secreted enzymes was analysed by gelatin zymography in buffer conditioned with diverse ZOE cements. Phenanthroline, a zinc chelator, was used to revert the inhibition of MMPs caused by zinc. The major gelatinolytic proteinases present in the conditioned media were characterized as MMP-2 and MMP-9 by immunoprecipitation. All ZOE cements inhibited MMPs activity, whereas phenanthroline could partially revert the inhibition caused by plain ZOE and Intermediate Restorative Material (IRM). PMID:15210026

Santos, M C L G; de Souza, A P; Gerlach, R F; Trevilatto, P C; Scarel-Caminaga, R M; Line, S R P

2004-07-01

340

Zinc stable isotope fractionation upon accelerated oxidative weathering of sulfidic mine waste.  

PubMed

Accelerated oxidative weathering in a reaction cell (ASTM D 5744 standard protocol) was performed over a 33 week period on well characterized, sulfidic mine waste from the Kidd Creek Cu-Zn volcanogenic massive sulfide deposit, Canada. The cell leachate was monitored for physicochemical parameters, ion concentrations and stable isotope ratios of zinc. Filtered zinc concentrations (<0.45 ?m) in the leachate ranged between 4.5 mg L(-1) and 1.9 g L(-1)-potentially controlled by pH, mineral solubility kinetics and (de)sorption processes. The zinc stable isotope ratios varied mass-dependently within +0.1 and +0.52‰ relative to IRMM 3702, and were strongly dependent on the pH (rpH-d66Zn=0.65, p<0.005, n=31). At a pH below 5, zinc mobilization was governed by sphalerite oxidation and hydroxide dissolution-pointing to the isotope signature of sphalerite (+0.1 to +0.16‰). Desorption processes resulted in enrichment of (66)Zn in the leachate reaching a maximum offset of +0.32‰ compared to the proposed sphalerite isotope signature. Over a period characterized by pH=6.1 ± 0.6, isotope ratios were significantly more enriched in (66)Zn with an offset of ? 0.23‰ compared to sphalerite, suggesting that zinc release may have been derived from a second zinc source, such as carbonate minerals, which compose 8 wt.% of the tailings. This preliminary study confirms the benefit of applying zinc isotopes alongside standard monitoring parameters to track principal zinc sources and weathering processes in complex multi-phase matrices. PMID:24784733

Matthies, R; Krahé, L; Blowes, D W

2014-07-15

341

Heat-sterilized silver oxide-zinc cells: Cycle life studies  

NASA Technical Reports Server (NTRS)

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 A-h were fabricated using 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 irradiated polyethylene film. Significant results of this study include the following: (1) cycle life in excess of 300 cycles was attained; (2) a zinc oxide/silver stoichiometric ratio of 1.5 resulted in greater cycle life than a ratio of 1.1, and similar cycle life to cells having a ratio of 2; (3) cells having methacrylic acid grafted separators suffered somewhat less in capacity loss due to zinc electrode shape change than cells having acrylic acid type; (4) use of acrylic acid grafted separators was slightly superior to the methacrylic acid type in respect to silver penetration; and (5) the inclusion of a layer of potassium titanate paper adjacent to the zinc electrodes resulted in cells that achieved higher cycle life before any of the group failed than that reached by cells of any other construction.

Arms, J. T.

1973-01-01

342

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

343

Magnetic Mn substituted cobalt zinc ferrite systems: Structural, electrical and magnetic properties and their role in photo-catalytic degradation of methyl orange azo dye  

NASA Astrophysics Data System (ADS)

The present work focuses on the effect of replacement of Fe3+ ions by the Mn3+ ions in cobalt zinc ferrites (Co0.6Zn0.4MnxFe2-xO4 (0.2, 0.4, 0.6, 0.8 and 1.0) on the structural, magnetic, electrical and catalytic properties. Powder X-ray diffraction studies confirmed that all the samples possessed cubic spinel structure with Fd-3m space groups. The saturation magnetization was found to decrease with increase in Mn3+ ions concentration. The drift mobility of all compositions was found to decrease with increase in temperature which could be attributed to the semiconductor nature of nanoferrites. The photo-catalytic activity of all the nanoferrites was evaluated by the degradation of methyl orange dye and it was observed that the degradation of methyl orange dye was enhanced with increase in Mn3+ ions concentration from 0.2 to 1.0. This might be due to the octahedral site preference and higher redox potential of manganese ion as compared those of iron.

Bhukal, Santosh; Bansal, S.; Singhal, Sonal

2014-07-01

344

Characterization of indium tin oxide and al-doped Zinc oxide thin films deposited by confocal RF magnetron sputter deposition  

Microsoft Academic Search

Thin film properties (resistivity, sheet resistance, optical transmissivity, stability testing under RH85\\/85C conditions and film stress) were measured for indium tin oxide (ITO) and Al-doped Zinc Oxide (ZnO) (2 wt.% Al doped target) films deposited using a confocal RF magnetron sputtering system. A comparison was made between sample biasing and high temperature conditions with respect to these properties. The sample

S. Jay Chey; Wei Liu; Min Yuan; David B. Mitzi

2009-01-01

345

The effect of substrate temperature on filtered vacuum arc deposited zinc oxide and tin oxide thin films  

Microsoft Academic Search

Zinc oxide (ZnO) and tin oxide (SnO2) thin films were deposited on commercial microscope glass and UV-fused silica (UVFS) substrates using a filtered vacuum arc deposition (FVAD) system. During the deposition, the substrates temperature was kept at room temperature (RT) or at 400°C. The film structure, surface morphology, and composition were determined using X-ray diffraction (XRD), atomic force microscopy (AFM),

E. Çetinörgü; S. Goldsmith; R. L. Boxman

2007-01-01

346

Microstructure, electrical properties, and degradation behavior of praseodymium oxides-based zinc oxide varistors doped with Y2O3  

Microsoft Academic Search

The microstructure, electrical properties, and degradation behavior of Pr-based zinc oxide varistors, which are composed of Zn-Pr-Co-Cr-Y oxides were investigated according to Y2O3 additive content in the range 0.5–4.0 mol%. The majority of the Sadded Y2O3 were segregated at the multiple ZnO grain junctions and grain boundaries. The average grain size was markedly decreased in the range 27.3–8.6 µm with

Choon-Woo Nahm; Choon-Hyun Park

2000-01-01

347

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

348

Characterization and photocatalytic activity of nanostructured indium tin oxide thin-film electrode for azo-dye degradation  

Microsoft Academic Search

Photocatalytically active indium tin oxide thin film electrodes were prepared by electron beam evaporation technique onto a glass substrate having thickness 120 nm. Degradation of reactive dye yellow direct 42 has been performed using photoeletrocatalysis. A biased potential is applied across indium tin oxide photoelectrode illuminated by UV light. The best experimental conditions were found to be dye concentration 1.0×10?5 mol L?1,

Mohammad Hossein Habibi; Nasrin Talebian; Jong-Ha Choi

2006-01-01

349

Indium-doped zinc oxide thin films prepared by rf magnetron sputtering  

Microsoft Academic Search

Indium-doped zinc oxide films have been prepared by rf magnetron sputtering, using ZnO targets containing up to 10 wt. % In2O3. Room temperature resistivity of the deposited films was found to decrease by about four orders of magnitude as the In2O3 content was increased from 0 to 10 wt. %.

I. Shih; C. X. Qiu

1985-01-01

350

Hydrogen Embrittlement of Steel in Metal Finishing Processes of Black Oxide and Zinc Phosphatize.  

National Technical Information Service (NTIS)

Static load tests were conducted with notched, steel tensile specimens after processing in black oxide (specification MIL-C-13924 Class 1) and also after processing in zinc phosphatize solution (specification MIL-P-16232C Type Z), to determine embrittleme...

R. H. Wolff

1966-01-01

351

Influence of DC magnetron sputtering parameters on the properties of amorphous indium zinc oxide thin film  

Microsoft Academic Search

Amorphous or crystalline indium zinc oxide (IZO) thin films, which are highly transparent and conducting, were deposited by DC magnetron sputtering. X-Ray diffraction technique was used for analyzing microstructures of the films, and also differential thermal analysis was performed for observing their crystallization behavior. The IZO thin films prepared were crystallized at much higher temperature than ITO films were. The

Yeon Sik Jung; Ji Yoon Seo; Dong Wook Lee; Duk Young Jeon

2003-01-01

352

Disruption of self-assembly and altered mechanical behavior in polyurethane\\/zinc oxide nanocomposites  

Microsoft Academic Search

The addition of less than 1vol%, 33nm zinc oxide nanoparticles into a polyurethane matrix resulted in approximately 40% decrease in the Young's modulus, 80% decrease in strain at fracture, and 50% decrease in the storage modulus, but at the same time resulted in an ?11°C increase in the glass transition temperature of the polymer. These results appear to contradict the

Junrong Zheng; Rahmi Ozisik; Richard W. Siegel

2005-01-01

353

Gas sensing properties of zinc oxide thin films prepared by spray pyrolysis  

NASA Astrophysics Data System (ADS)

Metal oxide semiconductors are widely employed as potential materials for the development of sensing devices for poisonous and inflammable gases. The change in resistivity of active material is exploited as a sensing parameter. A large volume of research work has been carried out in the last few decades on sensors and potential sensor materials. The advent of nanostructured materials has given a new impetus to the sensor research. Preparation and sensing response of zinc oxide thin films towards alcohol has been reported in this paper. Zinc oxide thin film has been prepared by using spray pyrolysis, using zinc acetate and methanol as the starting materials. The thin film was characterized for morphology and structure by using x-ray diffractometer (XRD) and field emission scanning electron microscope (FESEM) techniques. The results indicated that the ZnO particles are crystallized in the wurtzite hexagonal phase, which were well distributed in the films. Prepared zinc oxide thin film was exposed to different alcohols to check its gas sensing behaviour at different temperatures.

Singh, Onkar; Kohli, Nipin; Singh, Manmeet Pal; Anand, Kanika; Singh, Ravi Chand

2012-06-01

354

Zinc(II) oxide solubility and phase behavior in aqueous sodium phosphate solutions at elevated temperatures.  

National Technical Information Service (NTIS)

A platinum-lined, flowing autoclave facility is used to investigate the solubility/phase behavior of zinc(II) oxide in aqueous sodium phosphate solutions at temperatures between 290 and 560 K. ZnO solubilities are observed to increase continuously with te...

S. E. Ziemniak M. E. Jones K. E. S. Combs

1990-01-01

355

Development of Zinc-Oxide Non-Linear Resistors and Their Applications to Gapless Surge Arresters  

Microsoft Academic Search

Compared with conventional surge arresters which consists of silicon carbide valve elements and series gaps, the new gapless arrester utilizing a zinc oxide valve element offers more excellent characteristics. Meidensha has developed a new gapless arrester series with the rated voltages of 4.2 to 280 kV. Because of its compactness and gapless feature, this series is considered to be applicable

M. Kobayashi; M. Mizuno; T. Aizawa; M. Hayashi; K. Mitani

1978-01-01

356

Analytical and Experimental Approach to the Voltage Distribution on Gaoless Zinc-Oxide Surge Arresters  

Microsoft Academic Search

Studies on voltage distributions on gapless zinc-oxide surge arresters were conducted with both analysis and experiments. The analysis was conducted by the finite element method. A procedure advantageous in accuracy and computation time was proposed for analysis of fields involving floating potential metals needed for the design of arresters.

M. Oyama; I. Ohshima; M. Honda; M. Yamashita; S. Kojima

1981-01-01

357

Effect of water vapour on gallium doped zinc oxide nanoparticle sensor gas response  

Microsoft Academic Search

Zinc oxide is a wide band gap (~3.4 ev) semiconductor material, making it a promising material for high temperature applications, such as exhaust and flue environments where NO and NO2 monitoring is increasingly required due to stricter emission controls. In these environments water vapour and background levels of oxygen are present and, as such, the effect of humidity on the

Ruth Pearce; Fredrik Söderlind; Alexander Hagelin; P.-O. Kall; R. Yakimova; A. Lloyd Spetz; E. Becker; M. Skoglundh

2009-01-01

358

Intra-shell luminescence of transition-metal-implanted zinc oxide nanowires.  

PubMed

Zinc oxide nanowires were grown by vapor transport using the vapor-liquid-solid growth mechanism. The zinc oxide nanowires were implanted with transition metals (Co, Fe or Ni) and subsequently annealed in air at 700 degrees C for 30 min. Energy-dispersive x-ray spectroscopy and electron energy loss spectroscopy measurements reveal a successful incorporation of the desired transition metals. Transmission electron microscopy analysis of implanted and annealed zinc oxide nanowires shows a strongly damaged zinc oxide lattice but no formation of transition metal-rich secondary phases. The as-grown nanowires show a strong and intensive near-band edge emission and a moderately structured green luminescence band. After ion implantation, the structured green luminescence band increases in intensity and new sharp luminescence lines appear in the red luminescence region. Those sharp transitions are due to intra-shell 3d transitions of iron and cobalt in the corresponding Fe- and Co-doped ZnO samples. PMID:19420513

Müller, Sven; Zhou, Minjie; Li, Quan; Ronning, Carsten

2009-04-01

359

The Relative Oxidation Inhibition Performance of Some Neutral and Basic Zinc Dithiophosphate Salts  

Microsoft Academic Search

Recent engine testing on separate neutral and basic zinc dithiophosphates (ZnDTPs) showed a difference in valve train wear performance, with the neutral ZnDTP giving statistically better wear inhibition in Sequence VE tests. Since the literature was lacking on the oxidation inhibition performance of the separate neutral and basic salts, we systematically examined the relative antioxidancy of several neutral and basic

E. S. Yamaguchi; A. Onopchenko; M. M. Francisco; C. Y. Chan

1999-01-01

360

Subcutaneous Connective Tissue Reaction to Methacrylate Resin–based and Zinc Oxide and Eugenol Sealers  

Microsoft Academic Search

IntroductionAn evaluation was made of the connective tissue reaction in rats after subcutaneous implantation of methacrylate resin-based sealers (EndoREZ [Ultradent Products, Inc, South Jordan, UT] with a polymerization accelerator and RealSeal [Sybron Dental Specialties, Orange, CA]) and Pulp Canal Sealer (Sybron Dental Specialties), a zinc oxide and eugenol-based sealer used as the control.

Osvaldo Zmener; Cornelis H. Pameijer; Gabriel A. Kokubu; Daniel R. Grana

2010-01-01

361

Dependence of resistivity on structure and composition of AZO films fabricated by ion beam co-sputtering deposition  

NASA Astrophysics Data System (ADS)

The correlation between the resistivity and the structure/composition in the aluminum doped zinc oxide (AZO) films fabricated by the ion beam co-sputtering deposition at room temperature was investigated. The various compositions of AZO films were controlled by the sputtered area ratio of Al to Zn target. The structure, Al concentrations and resistivities of the as-deposited films were determined by X-ray diffractometer (XRD), energy dispersive spectrometer (EDS) and four-point probe station, respectively. The lowest resistivity of the deposited film was 5.66 × 10 -4 ?-cm at the 0.7 wt.% aluminum concentration. The most intense ZnO (0 0 2) diffraction peak, the largest grain size, the longest mean free path, and the highest free carrier concentration in the film result in the lowest resistivity of 5.66 × 10 -4 ?-cm at room temperature; simultaneously, the thermal stability of the resistivity of the AZO film as a function of the sample temperature was investigated. Below 200 °C the film's resistivity was almost kept at a fixed value and the lowest resistivity of 4.64 × 10 -4 ?-cm at 247 °C was observed.

Chen, Yu-Yun; Hsu, Jin-Cherng; Wang, Paul W.; Pai, Yao-Wei; Wu, Chih-Yuan; Lin, Yung-Hsin

2011-02-01

362

Effect of AZO seed layer on electrochemical growth and optical properties of ZnO nanorod arrays on ITO glass.  

PubMed

We report the structural and optical properties of ZnO nanorod arrays (NRAs) grown by an electrochemical deposition process. The ZnO NRAs were grown on indium tin oxide (ITO) coated glass substrates with a thin sputtered Al-doped ZnO (AZO) seed layer and compared with ones directly grown without the seed layer. The growth condition dependence of ZnO NRAs was investigated for various synthetic parameters. The morphology and density of the ZnO NRAs were accordingly controlled by means of zinc nitrate concentration and growth time. From photoluminescence results, the ultraviolet emission was significantly enhanced after thermal treatment. For ZnO NRAs grown on ITO glass without the seed layer, the diffuse transmittance was enhanced despite the reduction in the total transmittance, indicating a high haze value. By using a thin AZO seed layer, the well-aligned ZnO NRAs on AZO/ITO glass are controllably and reproducibly synthesized by varying the growth parameters, exhibiting a total transmittance higher than 91% in the visible wavelength range as well as good optical and crystal quality. PMID:21979460

Lee, Hee Kwan; Kim, Myung Sub; Yu, Jae Su

2011-11-01

363

Effect of AZO seed layer on electrochemical growth and optical properties of ZnO nanorod arrays on ITO glass  

NASA Astrophysics Data System (ADS)

We report the structural and optical properties of ZnO nanorod arrays (NRAs) grown by an electrochemical deposition process. The ZnO NRAs were grown on indium tin oxide (ITO) coated glass substrates with a thin sputtered Al-doped ZnO (AZO) seed layer and compared with ones directly grown without the seed layer. The growth condition dependence of ZnO NRAs was investigated for various synthetic parameters. The morphology and density of the ZnO NRAs were accordingly controlled by means of zinc nitrate concentration and growth time. From photoluminescence results, the ultraviolet emission was significantly enhanced after thermal treatment. For ZnO NRAs grown on ITO glass without the seed layer, the diffuse transmittance was enhanced despite the reduction in the total transmittance, indicating a high haze value. By using a thin AZO seed layer, the well-aligned ZnO NRAs on AZO/ITO glass are controllably and reproducibly synthesized by varying the growth parameters, exhibiting a total transmittance higher than 91% in the visible wavelength range as well as good optical and crystal quality.

Lee, Hee Kwan; Kim, Myung Sub; Yu, Jae Su

2011-11-01

364

Infrared spectroscopy of zinc oxide and magnesium nanostructures  

Microsoft Academic Search

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

Win Maw Hlaing Oo

2007-01-01

365

Nanocrystalline zinc oxide: Pyrolytic synthesis and spectroscopic characteristics  

NASA Astrophysics Data System (ADS)

Nanocrystalline and microcrystalline ZnO powders are synthesized by the pyrolysis of organic zinc salts in the presence of a reducing catalyst represented by a porous cellulose carrier. The specimens obtained are characterized by X-ray powder diffraction, energy dispersive analysis, scanning electron microscopy, and pulse cathodoluminescence. Lasing characteristics of the specimens are studied. The synthesis conditions, under which specimens with the crystallite morphology optimal for a low-threshold lasing are obtained, are found.

Demyanets, L. N.; Li, L. E.; Lavrikov, A. S.; Nikitin, S. V.

2010-01-01

366

Morphologies of zinc oxide particles and their effects on photocatalysis  

Microsoft Academic Search

ZnO powders with different morphologies were synthesized by alkali precipitation, organo-zinc hydrolysis, and spray pyrolysis. Acetaldehyde decomposition was used as a probe reaction to evaluate the photocatalysis of these ZnO powders. We investigated the relationship between photocatalytic activity and crystallinity, surface area, or morphology. Results indicate that the photocatalytic activity of ZnO powder depends on crystallinity rather than surface area

Di Li; Hajime Haneda

2003-01-01

367

Extracting indium and preparing ferric oxide for soft magnetic ferrite materials from zinc calcine reduction lixivium  

Microsoft Academic Search

A hydrometallurgical process for indium extraction and ferric oxide powder preparation for soft magnetic ferrite material\\u000a was developed. Using reduction lixivium from high-acid reductive leaching of zinc oxide calcine as raw solution, copper and\\u000a indium were firstly recovered by iron powder cementation and neutralization. The recovery ratios of Cu and In are 99% and\\u000a 95%, respectively. Some harmful impurities that

Jing He; Mo-tang Tang; Cun Zhou; Sheng-nan Wu; Yong-ming Chen; Tao Wang; Ling Huang

2011-01-01

368

Silicon metal-semiconductor–metal photodetector with zinc oxide transparent conducting electrodes  

Microsoft Academic Search

Transparent conducting oxides thin layers, due to their optical and electrical properties, can be used as transparent electrodes in various optoelectronic devices. We present a metal-semiconductor–metal photodiode (MSM-PD) on silicon as optically active layer with zinc oxide (ZnO) thin layer as interdigitated Schottky transparent electrodes. The advantage of using a ZnO thin layer as Schottky electrodes consists in the improvement

E. Budianu; M. Purica; F. Iacomi; C. Baban; P. Prepelita; E. Manea

2008-01-01

369

A study of mercuric oxide and zinc-air battery life in hearing aids.  

PubMed

The requirement to phase out mercuric oxide (mercury) batteries on environmental grounds has led to the widespread introduction of zinc-air technology. The possibility arises that high drain hearing aids may not be adequately catered for by zinc-air cells, leading to poor performance. This study investigated the hearing aid user's ability to perceive differences between zinc-air and mercury cells in normal everyday usage. The data was collected for 100 experienced hearing aid users in field trials. Users report 50 per cent greater life for zinc-air cells in high power aids and 28 per cent in low power aids. The average life of the zinc-air cells range from 15 days in high power to 34 days in low power aids. Users are able to perceive a difference in sound quality in favour of zinc-air cells for low and medium power aids. The hearing aid population is not disadvantaged by phasing out mercury cells. PMID:9373545

Sparkes, C; Lacey, N K

1997-09-01

370

Electrical effect of titanium diffusion on amorphous indium gallium zinc oxide  

NASA Astrophysics Data System (ADS)

In this work, thermal diffusion phenomenon of Ti into amorphous indium gallium zinc oxide (?-IGZO) was carefully investigated with secondary ion mass spectroscopy, I-V, and Rs 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 ?-IGZO during the oxidation of Ti, the number of oxygen vacancies working as electron-donating sites in ?-IGZO was dramatically increased, contributing to the decrease of resistivity (?) from 1.96 ? cm (as-deposited ?-IGZO) to 1.33 × 10-3 ? cm (350 °C annealed ?-IGZO).

Choi, Seung-Ha; Jung, Woo-Shik; Park, Jin-Hong

2012-11-01

371

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

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 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...

2010-07-01

372

Photoresponse of p-type zinc-doped iron(III) oxide thin films.  

PubMed

Stable zinc-doped iron(III) oxide thin films that exhibit p-type behavior were synthesized by spray pyrolytic deposition (SPD) on conducting indium-doped tin oxide-coated glass substrate. The highest photocurrent density of 1.1 mA/cm2 was observed at an illumination intensity of 40 mW/cm2 at -0.8 V vs Pt for zinc-doped p-Fe2O3 samples prepared at an optimum substrate temperature of 663 K using an optimum spray time of 70 s. A quantum efficiency of 21.1% at 325 nm was found for SPD samples prepared using a dopant concentration of 0.0088 M zinc nitrate hexahydrate. X-ray diffraction results showed structures of alpha-Fe2O3 and ZnFe2O4. A direct band gap energy of 2.2 eV was found from monochromatic photocurrent density data and agrees closely with the band gap obtained from UV-vis absorption. The X-ray photoelectron spectroscopy results also confirm the presence of zinc dopant (4.0 atomic %) in thin films of zinc-doped p-Fe2O3. PMID:15315424

Ingler, William B; Baltrus, John P; Khan, Shahed U M

2004-08-25

373

Zinc Oxide Surge Arresters and HVDC 125kV-upgrade 500kV Converter Stations  

Microsoft Academic Search

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

Shingo Shirakawa; Takayuki Kobayashi; Yoshinao Matsushita; Takehisa Sakai; Hironori Suzuki; Yuzo Ozaki

2009-01-01

374

Surface morphology and electrical transport of rapid thermal annealed chromium-doped indium zinc oxides: The influence of zinc interstitials and out-diffusion  

NASA Astrophysics Data System (ADS)

We investigate the complex impedance (CI) spectra of chromium-doped indium zinc oxide (CIZO) films with different rapid thermal annealing (RTA) temperatures. The CI spectra drawn from the impedance contributions of Zn-O and In-O bondings in CIZO films were analyzed by two sets of parallel resistance and capacitance components in series. The result demonstrates that zinc interstitials controls electron concentration and transition of electrical transport from semiconducting to metallic. At higher RTA temperature, high-density zinc interstitial promotes Zn atom diffusion from the surface, modifying surface morphology.

Hsu, C. Y.

2013-12-01

375

Lactic acid aided electrochemical deposition of c -axis preferred orientation of zinc oxide thin films: Structural and morphological features  

NASA Astrophysics Data System (ADS)

Compact and homogeneous c-axis preferred orientation of zinc oxide (ZnO) films on indium tin oxide (ITO) coated glass have been prepared electrochemically at -1.2 V vs. Ag|AgCl in a weak acidic condition from 0.06 M Zn(NO 3) 2 with 3 mM lactic acid (LA) added. LA was found having strong influence on the electrodeposition of c-axis preferred orientation of zinc oxide films. Other experimental variables such as deposition temperature, potential, and precursor concentration were also conducted in this article. Among these variables, it was found that precursor concentration of zinc nitrate influenced significantly on growth direction and crystal diameter of zinc oxide. Cyclic voltammetry was used to observe the electrochemistry of the deposition. Crystallinities of the films were examined by X-ray diffractometer. The morphologies of zinc oxide films were observed with a field emitting scanning electron microscope. Optical characteristics of zinc oxide layers were measured with UV-vis spectrophotometer. The band gap of the deposited zinc oxide thin films was evaluated from the Tauc relationship of ( ?h?) 2 vs. h?, which was found to be 3.31 eV.

Whang, Thou-Jen; Hsieh, Mu-Tao; Tsai, Jia-Ming; Lee, Shyan-Jer

2011-09-01

376

Laser prepared organic heterostuctures on glass/AZO substrates  

NASA Astrophysics Data System (ADS)

This paper presents some studies about the bi-layer organic heterostructures realized with zinc phthalocyanine (ZnPc) as donor layer and 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA) as acceptor layer, on substrate of glass covered by Al doped ZnO (AZO) layer. These heterostructures have been prepared using laser techniques: pulsed laser deposition (PLD) in an atmosphere of oxygen for AZO films deposition and matrix assisted pulsed laser evaporation (MAPLE) for organic films deposition. The influence of the deposition conditions on the transmission of the organic films has been analysed. The effect of the oxygen plasma treatment, with duration of 5 min and 10 min, on the surface topography, structural and optical properties of AZO layers deposited by PLD and, as consequence, on the optical and electrical properties of the single layer (ZnPc) and bi-layer (ZnPc/NTCDA) organic heterostructure, deposited by MAPLE, was investigated.

Stanculescu, Anca; Socol, Marcela; Rasoga, Oana; Mihailescu, Ion N.; Socol, Gabriel; Preda, Nicoleta; Breazu, Carmen; Stanculescu, Florin

2014-05-01

377

Physical vapor deposited zinc oxide nanoparticles for direct electron transfer of superoxide dismutase  

Microsoft Academic Search

This communication describes a novel and facile approach to direct electron transfer of copper, zinc–superoxide dismutase (Cu, Zn–SOD) at a physical vapor deposited zinc oxide (ZnO) nanoparticles surface. SOD exhibits quasi-reversible electrochemical behavior in phosphate buffer solution (PBS, pH 7.25), with apparent formal potential of 195.2±4.6mV vs. Ag|AgCl and high heterogeneous electron rate constant of 10.4±1.8s?1. Electrochemical results indicate that

Zifeng Deng; Yang Tian; Xia Yin; Qi Rui; Haiqing Liu; Yongping Luo

2008-01-01

378

High-stability oxygen sensor based on amorphous zinc tin oxide thin film transistor  

NASA Astrophysics Data System (ADS)

This research presents a sol-gel derived zinc tin oxide thin film transistor (TFT) as a high-stability oxygen sensor. Due to its high sensitivity, oxygen has been traditionally regarded as having a negative influence on the electrical characteristics of zinc-based TFTs; however, TFTs can also act as an oxygen sensor. After illumination with visible light in oxygen-rich ambient, a significant increase in drain current of nearly 104 times occurs with fixed gate and drain voltages. It is expected that an optimized method of illumination can help to reset the electrical characteristics or distinguish the on/off state of this reliable oxygen sensor.

Chen, Yu-Chun; Chang, Ting-Chang; Li, Hung-Wei; Chung, Wan-Fang; Wu, Chang-Pei; Chen, Shih-Ching; Lu, Jin; Chen, Yi-Hsien; Tai, Ya-Hsiang

2012-06-01

379

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

380

Cytosolic Superoxide Dismutase (SOD1) Is Critical for Tolerating the Oxidative Stress of Zinc Deficiency in Yeast  

Microsoft Academic Search

Zinc deficiency causes oxidative stress in many organisms including the yeast Saccharomyces cerevisiae. Previous studies of this yeast indicated that the Tsa1 peroxiredoxin is required for optimal growth in low zinc because of its role in degrading H2O2. In this report, we assessed the importance of other antioxidant genes to zinc-limited growth. Our results indicated that the cytosolic superoxide dismutase

Chang-Yi Wu; Janet Steffen; David J. Eide; Julian Rutherford

2009-01-01

381

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

382

Physico-chemical characterization and photocatalytic activity of zinc oxide prepared by various methods.  

PubMed

Zinc oxide was prepared by different methods by varying precipitating agents, the source of the salt precursors and the microwave irradiation time and was characterized by XRD, BET-surface area, surface acidity and crystallite sizes. The photocatalytic reactions were carried out under solar radiation in batch reactors towards oxidation of 4-nitrophenol and reduction of Cr(VI) by varying different parameters such as irradiation time, pH of the solution, catalyst amount and substrate concentration and the activities were correlated with the physico-chemical parameters. Zinc oxide samples prepared by microwave irradiation and calcined at 300 degrees C exhibit highest surface area, acid sites and lowest crystallite sizes and show highest activity towards photocatalytic reactions. PMID:16423360

Parida, K M; Dash, S S; Das, D P

2006-06-15

383

Electrical and optical properties of doped tin and zinc oxide thin films by atmospheric pressure chemical vapor deposition  

SciTech Connect

Zinc oxide and tin oxide films have been deposited by atmospheric pressure chemical vapor deposition. Zinc oxide films doped with fluorine have higher mobility and higher visible transmission than those doped with the Group III elements (B, Al, Ga). A ZnO:F film with a sheet resistance of 5 [Omega]/square has an average visible absorption of about 3%. Various doped zinc oxide films were compared with each other and with SnO[sub 2]:F films through their Figure of Merit, which is defined as the ratio of the conductivity over the visible absorption coefficient. Zinc oxide films doped with fluorine have the highest Figure of Merit and are very promising as transparent electrodes for solar cells with high cell efficiency.

Hu, J.; Gordon, R.G. (Department of Chemistry, Harvard University, Cambridge, Massachusetts 02138 (United States))

1992-12-01

384

Oxidation of 8-Oxo-7,8-dihydro-2?-deoxyguanosine by Oxyl Radicals Produced by Photolysis of Azo Compounds  

PubMed Central

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 are consisted with 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 (O2•?) and ROO• radicals in approximately 1:1 ratios, as demonstrated by experiments with Cu, Zn superoxide dismutase to form dehydroguanidinohydantoin (Ghox) 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-acetylguanosine (tri-O-Ac-G), 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-Ghox and 5?-d(CCATC[Ghox]CTACC products.

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

2010-01-01

385

Differential impact of zinc deficiency on phagocytosis, oxidative burst, and production of pro-inflammatory cytokines by human monocytes.  

PubMed

Zinc deficiency has a fundamental influence on the immune defense, with multiple effects on different immune cells, resulting in a major impairment of human health. Monocytes and macrophages are among the immune cells that are most fundamentally affected by zinc, but the impact of zinc on these cells is still far from being completely understood. Therefore, this study investigates the influence of zinc deficiency on monocytes of healthy human donors. Peripheral blood mononuclear cells, which include monocytes, were cultured under zinc deficient conditions for 3 days. This was achieved by two different methods: by application of the membrane permeable chelator N,N,N',N'-tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) or by removal of zinc from the culture medium using a CHELEX 100 resin. Subsequently, monocyte functions were analyzed in response to Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. Zinc depletion had differential effects. On the one hand, elimination of bacterial pathogens by phagocytosis and oxidative burst was elevated. On the other hand, the production of the inflammatory cytokines tumor necrosis factor (TNF)-? and interleukin (IL)-6 was reduced. This suggests that monocytes shift from intercellular communication to basic innate defensive functions in response to zinc deficiency. These results were obtained regardless of the method by which zinc deficiency was achieved. However, CHELEX-treated medium strongly augmented cytokine production, independently from its capability for zinc removal. This side-effect severely limits the use of CHELEX for investigating the effects of zinc deficiency on innate immunity. PMID:24823619

Mayer, Lena S; Uciechowski, Peter; Meyer, Sören; Schwerdtle, Tanja; Rink, Lothar; Haase, Hajo

2014-06-25

386

Evaluation of growth and biochemical indicators of Salvinia natans exposed to zinc oxide nanoparticles and zinc accumulation in plants.  

PubMed

The adverse effects of zinc oxide nanoparticles (ZnO NPs) with an average diameter of 25 nm on the aquatic plant Salvinia natans (L.) All. were determined. Growth, superoxide dismutase (SOD) activity, catalase (CAT) activity, peroxidase activity, and chlorophyll content of the plants were measured after 7 days of exposure to different concentrations of ZnO NPs (1 to 50 mg L(-1)). The particle distribution in the culture medium (without plants) during the first 24 h was determined using a Nanotrac 250 particle analyzer. We also investigated the zinc accumulation in leaves and roots of the plant after 7 days of exposure. Exposure to 50 mg L(-1) ZnO NPs significantly increased SOD and CAT activities (P??0.05). NPs completely precipitated at the bottom of the container at 8 h except for the portions of dissolution and aggregation on the roots. ZnO NPs at a concentration of 50 mg L(-1) can adversely affect S. natans, and their stress is affected by their aggregation and dissolution. PMID:23860598

Hu, Changwei; Liu, Xu; Li, Xiuling; Zhao, Yongjun

2014-01-01

387

A more efficient pathway for synthesis of zinc-doped superparamagnetic iron oxide nanocrystals with enhanced saturation magnetization  

Microsoft Academic Search

Zinc-doped superparamagnetic iron oxide nanocrystals (Zn-SPIONs) with enhanced saturation magnetization have been successfully synthesized using iron-oleate and zinc-oleate as precursors through facial hydrothermal approach. The synthetic procedure is new and more convenient compared with thermal decomposition method which requires expensive solvent, protective atmosphere and well-controlled heating rate.

Chen Feng; Wenbo Bu; Jianlin Shi

2010-01-01

388

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

389

Polymer light-emitting diodes with amorphous indium-zinc oxide anodes deposited at room temperature  

Microsoft Academic Search

The authors report on the performance of polymer-based light-emitting diodes, LEDs, using amorphous zinc oxide-doped indium oxide, IZO, as anode. In particular, LEDs with poly[(2-methoxy-5-(2?-ethyl-hexyloxy)-1,4-phenylene vinylene] as electroluminescent layer and aluminium cathodes, show higher efficiency with this IZO anode (0.015cd\\/A) than with indium-tin oxide (ITO) (0.010cd\\/A). Inspite of the higher resistance of this IZO electrode, compared with ITO, the fact

Gabriel Bernardo; Gonçalo Gonçalves; Pedro Barquinha; Quirina Ferreira; Graça Brotas; Luís Pereira; Ana Charas; Jorge Morgado; Rodrigo Martins; Elvira Fortunato

2009-01-01

390

Chemism and kinetics of the oxidation of zinc-calcium oxysulfide  

NASA Astrophysics Data System (ADS)

The sequence of phase transformations and the kinetics of the solid-phase (heating to 1273 K) oxidation of zinc-calcium oxysulfide CaZnSO with air are determined by thermodynamic, thermogravimetric, mass spectrometric, and X-ray diffraction analyses. The oxidation process is shown to be accompanied by the formation of the CaSO4 and ZnO phases depending on the heating conditions, as well as by the formation of CaO with SO2 evolution. The two-stage oxidation of CaZnSO is interpreted by the Avrami-Erofeev kinetic equations with activation energies of 190 and 422 kJ/mol.

Gulyaeva, R. I.; Selivanov, E. N.; Mansurova, A. N.

2013-05-01

391

Zinc oxide nanorods modified indium tin oxide surface for amperometric urea biosensor.  

PubMed

ZnO nanorods (ZnONR) grown onto indium-tin-oxide (ITO) coated glass surface using zinc nitrate hexahydrate/hexamethylenetetramine (HMT) in aqueous phase has been utilized for urea biosensor. Urease (Urs) was immobilized onto ZnONR/ITO at physiological pH via electrostatic interactions between Urs and ZnO to fabricate Urs/ZnONR/ITO bioelectrode. ZnONR/ITO electrode has been characterized using XRD, FE-SEM techniques and Urs/ZnONR/ITO bioelectrode using electrochemistry. The XRD and FE-SEM measurements confirm the formation of ZnO nanorods in wurtzite structure. Cyclic voltammetric and amperometric measurements on the Urs/ZnONR/ITO biolectrode for urea concentrations in the range of 1-20 mM reveal 0.4 microA mM(-1) sensitivity, with a response time of 3 seconds, and a detection limit of 0.13 mM. The Michaelis-Menten constant (Km) was calculated to be 9.09 mM. Results indicate that ZnO nanorods provide suitable microenvironment for urease immobilization and can be utilized in biosensor design and other biological applications. PMID:22103068

Palomera, Netzahualcóyotl; Balaguera, Marcia; Arya, Sunil K; Hernández, Samuel; Tomar, Maharaj S; Ramírez-Vick, Jaime E; Singh, Surinder P

2011-08-01

392

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

393

Effect of zinc and nitric oxide on monocyte adhesion to endothelial cells under shear stress.  

PubMed

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/cm(2) or 1 dyne/cm(2)) or reversing shear stress (time average 1 dyne/cm(2)) for 24 h. 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 H(2)O(2) and superoxide together with relatively low levels of nitric oxide (NO) production. L-N(G)-Nitroarginine methyl ester (L-NAME) treatment increased monocyte adhesion under 15 dynes/cm(2) 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. PMID:22009315

Lee, Sungmun; Eskin, Suzanne G; Shah, Ankit K; Schildmeyer, Lisa A; McIntire, Larry V

2012-03-01

394

Zinc oxide nanoflower prepared by wet colloid chemical method  

NASA Astrophysics Data System (ADS)

Flower-like ZnO nanostructure of novel morphologies has been fabricated by a simple wet colloid chemical method. A two-step wet chemical process has been used to prepare ZnO nanoflower on glass substrates using zinc acetate dihydrate [Zn(CH3COO)2?2H2O] at room temperature. Growth structure of the nanoflowers has been investigated by SEM. UV-Vis absorption spectrum shows an absorption band at 355 nm due to nanosize ZnO. Photoluminescence spectrum exhibits two emission peaks - one at 351 nm corresponding to band gap excitonic emission and another located at 470 nm due to the presence of ionized oxygen vacancies.

Mahato, S.; Das, S.; Kar, A. K.

2014-04-01

395

Investigation of low-zinc-solubility electrodes and electrolytes in zinc/silver oxide cells  

NASA Astrophysics Data System (ADS)

The cycle-life performance of the Zn/AgO cell is limited by high rates of Zn active material redistribution (shape change) and Zn dendrite growth. Reduced-zinc-solubility electrolytes, prepared by adding F -, CO 32-, BO 33- and PO 43- salts to aqueous KOH solutions, were used in 5 A h Zn/AgO cells to determine their effect on cell lifetimes. Ca(OH) 2 additions to the Zn electrode were also evaluated in cells of the same capacity and mass as the calcium-free cells. It was found that all of the anion additives to KOH electrolytes resulted in lower cell capacities and shorter lifetimes, which could be attributed the formation of soluble Ag-containing salts and subsequent degradation of the Ag electrode performance. The calcium-containing Zn electrode was found to significantly improve the performance of the Zn/AgO cell by promoting higher capacities, especially over the initial 20 cycles. The higher capacities could be attributed to the formation of a calcium zincate complex, crystals of which were found in the cycled Zn electrodes.

Chen, Jenn-Shing; McLarnon, Frank R.; Cairns, Elton J.

396

The role of pH variation on the growth of zinc oxide nanostructures  

NASA Astrophysics Data System (ADS)

In this paper we present a systematic study on the morphological variation of ZnO nanostructure by varying the pH of precursor solution via solution method. Zinc acetate dihydrate and sodium hydroxide were used as a precursor, which was refluxed at 90 °C for an hour. The pH of the precursor solution (zinc acetate di hydrate) was increased from 6 to 12 by the controlled addition of sodium hydroxide (NaOH). Morphology of ZnO nanorods markedly varies from sheet-like (at pH 6) to rod-like structure of zinc oxide (pH 10-12). Diffraction patterns match well with standard ZnO at all pH values. Crystallinity and nanostructures were confirmed by high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) pattern, which indicates structure grew along [0 0 0 1] direction with an ideal lattice fringes distance 0.52 nm. FTIR spectroscopic measurement showed a standard peak of zinc oxide at 464 cm -1. Amount of H + and OH - ions are found key to the structure control of studied material, as discussed in the growth mechanism.

Wahab, Rizwan; Ansari, S. G.; Kim, Young Soon; Song, Minwu; Shin, Hyung-Shik

2009-02-01

397

Gills are an initial target of zinc oxide nanoparticles in oysters Crassostrea gigas, leading to mitochondrial disruption and oxidative stress.  

PubMed

The increasing industrial use of nanomaterials during the last decades poses a potential threat to the environment and in particular to organisms living in the aquatic environment. In the present study, the toxicity of zinc oxide nanoparticles (ZnONP) was investigated in Pacific oysters Crassostrea gigas. The nanoscale of ZnONP, in vehicle or ultrapure water, was confirmed, presenting an average size ranging from 28 to 88nm. In seawater, aggregation was detected by TEM and DLS analysis, with an increased average size ranging from 1 to 2?m. Soluble or nanoparticulated zinc presented similar toxicity, displaying a LC50 (96h) around 30mg/L. High zinc dissociation from ZnONP, releasing ionic zinc in seawater, is a potential route for zinc assimilation and ZnONP toxicity. To investigate mechanisms of toxicity, oysters were treated with 4mg/L ZnONP for 6, 24 or 48h. ZnONP accumulated in gills (24 and 48h) and digestive glands (48h). Ultrastructural analysis of gills revealed electron-dense vesicles near the cell membrane and loss of mitochondrial cristae (6h). Swollen mitochondria and a more conspicuous loss of mitochondrial cristae were observed after 24h. Mitochondria with disrupted membranes and an increased number of cytosolic vesicles displaying electron-dense material were observed 48h post exposure. Digestive gland showed similar changes, but these were delayed relative to gills. ZnONP exposure did not greatly affect thiol homeostasis (reduced and oxidized glutathione) or immunological parameters (phagocytosis, hemocyte viability and activation and total hemocyte count). At 24h post exposure, decreased (-29%) glutathione reductase (GR) activity was observed in gills, but other biochemical responses were observed only after 48h of exposure: lower GR activity (-28%) and levels of protein thiols (-21%), increased index of lipid peroxidation (+49%) and GPx activity (+26%). In accordance with ultrastructural changes and zinc load, digestive gland showed delayed biochemical responses. Except for a decreased GR activity (-47%) at 48h post exposure, the biochemical alterations seen in gills were not present in digestive gland. The results indicate that gills are able to incorporate zinc prior (24h) to digestive gland (48h), leading to earlier mitochondrial disruption and oxidative stress. Our data suggest that gills are the initial target of ZnONP and that mitochondria are organelles particularly susceptible to ZnONP in C. gigas. PMID:24745718

Trevisan, Rafael; Delapedra, Gabriel; Mello, Danielle F; Arl, Miriam; Schmidt, Eder C; Meder, Fabian; Monopoli, Marco; Cargnin-Ferreira, Eduardo; Bouzon, Zenilda L; Fisher, Andrew S; Sheehan, David; Dafre, Alcir L

2014-08-01

398

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

399

Water oxidation catalysts and pH sensors based on azo-conjugated iridium/rhodium motifs.  

PubMed

Herein we report the molecular structures and electronic properties of ionic, hydrophobic half-sandwich complexes with formula [?(5)-Cp*Ir(L)(Cl)](OTf) (), [?(5)-Cp*Rh(L)(Cl)](OTf) (), [?(5)-Cp*Ir(L)(H2O)](OTf)2 () and [?(5)-Cp*Rh(L)(H2O)](OTf)2 (), where L is 1-(2-pyridylazo)-2-naphthol. The electrochemical properties of these complexes have been investigated, and they displayed good electronic properties for use as water oxidation catalysts. Interestingly, the color of their solutions is unambiguously transformed from brown to green at pH = 12; the color changes of , and are especially apparent. For this reason, their use as pH sensors for detecting solution pH values can be explored. PMID:24828473

Yu, Wei-Bin; He, Qing-Ya; Shi, Hua-Tian; Pan, Yan; Wei, Xianwen

2014-07-22

400

The histopathology of rat lung following exposure to zinc oxide/hexachloroethane smoke or installation with zinc chloride followed by treatment with 70% oxygen.  

PubMed Central

The effects of inhaled zinc oxide/hexachloroethane smoke (11,580 mg x min/m3) and intratracheally instilled zinc chloride (2.5 mg/kg body weight) have been studied in rat lung. The effects of subsequent treatment with 70% oxygen have been studied after both procedures. Both the inhalation of the smoke and instillation of zinc chloride produced similar effects that included pulmonary edema, alveolitis and, at a later stage, some fibrosis. After zinc chloride instillation, the pathological changes largely spared the periphery of the lung, while following smoke inhalation they were more diffuse. Subsequent oxygen administration had little effect on the development or progression of the pathological changes. Images FIGURE 5. FIGURE 6. FIGURE 7. FIGURE 8.

Brown, R F; Marrs, T C; Rice, P; Masek, L C

1990-01-01

401

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

402

Cytotoxicity of cultured macrophages exposed to antimicrobial zinc oxide (ZnO) coatings on nanoporous aluminum oxide membranes  

PubMed Central

Zinc oxide (ZnO) is a widely used commercial material that is finding use in wound healing applications due to its antimicrobial properties. Our study demonstrates a novel approach for coating ZnO with precise thickness control onto 20 nm and 100 nm pore diameter anodized aluminum oxide using atomic layer deposition (ALD). ZnO was deposited throughout the nanoporous structure of the anodized aluminum oxide membranes. An 8 nm-thick coating of ZnO, previously noted to have antimicrobial properties, was cytotoxic to cultured macrophages. After 48 h, ZnO-coated 20 nm and 100 nm pore anodized aluminum oxide significantly decreased cell viability by ?65% and 54%, respectively, compared with cells grown on uncoated anodized aluminum oxide membranes and cells grown on tissue culture plates. Pore diameter (20–200 nm) did not influence cell viability.

Petrochenko, Peter E.; Skoog, Shelby A.; Zhang, Qin; Comstock, David J.; Elam, Jeffrey W.; Goering, Peter L.; Narayan, Roger J.

2013-01-01

403

Carrier transport in polycrystalline transparent conductive oxides: A comparative study of zinc oxide and indium oxide  

Microsoft Academic Search

Highly doped indium-tin oxide films exhibit resistivities ? as low as  1.2×10?4 ? cm, while for ZnO films resistivities in the range of 2 to 4×10?4 ? cm are reported. This difference is unexpected, if ionized impurity scattering would be dominant for carrier concentrations above 1020 cm?3. By comparing the dependences of the effective Hall mobility on the carrier concentration of ZnO and

Klaus Ellmer; Rainald Mientus

2008-01-01

404

Influence of Roughness Surfaces on Third-Order Nonlinear-Optical Properties of Erbium-Doped Zinc Oxide Thin Films  

Microsoft Academic Search

Zinc oxide (ZnO) and erbium-doped zinc oxide (ZnO:Er) thin films were deposited on heated glass substrates using the spray pyrolysis technique. Third-order nonlinear-optical properties of the thin films have been investigated using the third harmonic generation (THG) at wavelength of 1064 nm in picosecond regime. The dependence of third-order nonlinear susceptibility and transmission characteristics on the thin films roughness has been

M. Alaoui Lamrani; M. El Jouad; M. Addou; T. El Habbani; N. Fellahi; K. Bahedi; M. Ebn Touhami; Z. Essaidi; Z. Sofiani; B. Sahraoui; A. Meghea; I. Rau

2008-01-01

405

Advantages of using amorphous indium zinc oxide films for window layer in Cu(In,Ga)Se 2 solar cells  

Microsoft Academic Search

The advantages of using indium zinc oxide (IZO) films instead of conventional Ga-doped zinc oxide (ZnO:Ga) films for Cu(In,Ga)Se2 (CIGS) solar cells are described. The electrical properties of IZO are independent of film thickness. IZO films have higher mobility (30–40cm2\\/Vs) and lower resistivity (4–5×10?4?cm) compared to ZnO:Ga films deposited without intentional heating, because the number of grain boundaries in amorphous

Moe Warasawa; Akira Kaijo; Mutsumi Sugiyama

406

Effect of the carrier gas composition on the electrical and luminescent properties of CVD-grown zinc oxide films  

NASA Astrophysics Data System (ADS)

The electrical and luminescent properties of zinc oxide films grown by CVD on sapphire substrates with different carrier gases are investigated. It is found that hydrogen, oxygen, and ammonia used as a carrier gas in the growth process insignificantly influence the defect structure and impurity content in the crystal. Only hydrogen decreases the density of radiative recombination centers responsible for the green luminescence band typical of zinc oxide.

Bagamadova, A. M.; Zobov, E. M.; Omaev, A. K.

2014-05-01

407

Effect of aluminum and indium co-doping on zinc oxide films prepared by dc magnetron sputtering  

Microsoft Academic Search

Aluminum and indium co-doped zinc oxide (AIZO) thin films were prepared by direct current (dc) magnetron sputtering on glass substrate in pure argon atmosphere. Three inches of zinc oxide ceramic with 0.5wt.% of aluminum and indium doping was used as a target in static mode. The influence of sputtering conditions i.e. substrate–target distance, pressure and power on AIZO films was

T. Tohsophon; N. Wattanasupinyo; B. Silskulsuk; N. Sirikulrat

2011-01-01

408

Solution-processed zinc-tin-oxide thin-film transistor by electrohydrodynamic spray  

NASA Astrophysics Data System (ADS)

Solution-processed zinc-tin-oxide film was coated by electrohydrodynamic (EHD) jet. By using EHD spray technique, zinc-tin-oxide (ZTO) TFT was prepared and characterized for the first time. The optimized process parameters were as follows: an electrical voltage of 3 KV to apply nozzle, a solution pursing of 0.032 µ l per sec, a distance of 45 mm between nozzle and substrate for 30 sec with a 0.3 M of ZTO solution. The electrical properties were obtained as follows; a mobility of 2.0 cm2/Vs, a current ratio Ion/Ioff of 105, a threshold voltage of -10 V, a subthreshold slope of 1.74 V/dec. Based on this result, more in-depth research should be performed in this specific area for further development and electronic applications.

Kwack, Young-Jin; Choi, Woon-Seop

2012-06-01

409

Mechanism of ferromagnetism in non-magnetic ion-doped zinc oxides  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) that contains non-magnetic ionic dopants, such as nitrogen (N)-doped zinc oxide (ZnO:N), has been observed to exhibit ferromagnetism. Ferromagnetism is proposed to arise from the Coulomb excitation in the localized states that is induced by the oxygen vacancy, V O. A model based on the Coulomb excitation that is associated with the electron-phonon interaction theoretically explains the ferromagnetic mechanism of ZnO:N. This study reveals that the ferromagnetism will be induced by either deep localized states with a small V O concentration or shallow localized states with a high V O concentration. Additionally, electron-phonon coupling either suppresses the ferromagnetism that is induced by the deep donor states of V O or enhances the ferromagnetism that is induced by the shallow donor states of V O.

Sun, Shih-Jye; Yu, Chang-Feng; Hsu, Hua-Shu; Chou, Hsiung; Du, Ai-Jun

2014-01-01

410

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

411

Theoretical study of structural, optical and electrical properties of zirconium-doped zinc oxide  

Microsoft Academic Search

The structural, optical and electrical properties of zirconium-doped zinc oxide have been investigated by first principle calculations. Three possible structures including substitutional Zr for Zn (ZrZn), interstitial Zr (Zri) and substitutional Zr for O (ZrO) are considered. The results show that the formation energy of ZrZn defect is the lowest, which indicates that ZrZn defect forms easier and its concentration

Fenggong Wang; Maoshui Lv; Zhiyong Pang; Tianlin Yang; Ying Dai; Shenghao Han

2008-01-01

412

Engineering evaluation of the zinc-mercuric oxide battery\\/nickel-cadmium battery hybrid system  

Microsoft Academic Search

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. However, at 70F, the Zn\\/HgO battery-NiCd battery hybrid system failed to provide as much capacity as the Zn\\/HgO battery alone because of overcharge during the

D. B. Wood

1974-01-01

413

Voltage-controlled DC reactive magnetron sputtering of indium-doped zinc oxide films  

Microsoft Academic Search

Transparent and conducting indium-doped zinc oxide (IZO) films were deposited by DC reactive magnetron sputtering from Zn+2.5 at.% In alloy target. Stabilization of the operating point in the transition region was achieved by means of controlling the cathode voltage. The discharge current and the argon flow were kept constant. The drift of the cathode voltage was compensated for by induced

H. Czternastek; A. Brudnik; M. Jachimowski; E. Kolawa

1992-01-01

414

Electron weak localization, and electron–phonon interaction in amorphous zinc-doped indium oxide films  

Microsoft Academic Search

We have systematically investigated the temperature dependence of resistivity ? and Hall coefficient RH of indium zinc oxide films with thickness d=350 nm in the temperature range 2.0 K to 300 K. Specimen films with ??3?17 ?? m (300 K) show metallic characteristics (??T) at temperatures above 100 K. At low temperatures below 20 K, the resistivity slightly increases with decreasing temperature because of the quantum effects

K. Makise; M. Funaki; B. Shinozaki; K. Yano; Y. Shimane; K. Inoue; H. Nakamura

2008-01-01

415

Nanostructured Zinc Oxide Particles in Chemically Modified Electrodes for Biosensor Applications  

Microsoft Academic Search

Zinc oxide (ZnO) has received considerable attention because of its unique optical, semiconducting, piezoelectric, and magnetic properties. ZnO nanostructures exhibit interesting properties including high catalytic efficiency and strong adsorption ability. Recently, the interest has been focused toward the application of ZnO in biosensing because of its high isoelectric point (9.5), biocompatibility, and fast electron transfer kinetics. Such features advocate the

S. Ashok Kumar

2008-01-01

416

Electronic properties of a zinc oxide nanotube under uniaxial tensile strain: a density functional theory study  

Microsoft Academic Search

In this article, density functional theory calculations were employed to investigate the electronic properties of (4,4) armchair\\u000a zinc oxide single-walled nanotubes (ZNONTs) under uniaxial mechanical deformations. It was found that the highest-occupied\\u000a molecular orbital and the lowest-unoccupied molecular orbital gap and the value of radial buckling will both decrease linearly\\u000a with the increase of axial strain. The elongation of the

Shin-Pon Ju; Meng-Hsiung Weng; Chia-Hung Lee

417

A highly selective ammonia gas sensor using surface-ruthenated zinc oxide  

Microsoft Academic Search

Preparation and characterisation of a highly selective surface-ruthenated zinc oxide sensor for ammonia in trace levels is demonstrated. The introduction of some RuO linkages on the surface of ZnO leads to a dramatic enhancement in the sensitivity (S) to 1000 ppm level of ammonia at 300°C (S=440) as compared to the similar response obtained for pure ZnO (S=1.5). A systematic

M Aslam; V. A Chaudhary; I. S Mulla; S. R Sainkar; A. B Mandale; A. A Belhekar; K Vijayamohanan

1999-01-01

418

Photocatalytic self-cleaning properties of cellulosic fibers modified by nano-sized zinc oxide  

Microsoft Academic Search

Nano-sized zinc oxide was synthesized and deposited onto cellulosic fibers using the sol–gel process at ambient temperature. The prepared materials were characterized using several techniques including scanning electron microscopy, transmission electron microscopy, diffuse reflectance spectroscopy, X-ray diffraction and thermogravimetric analysis. X-ray diffraction studies of the ZnO-coated fiber indicate formation of the hexagonal crystal phase which was satisfactory crystallized on the

Hadi Fallah Moafi; Abdollah Fallah Shojaie; Mohammad Ali Zanjanchi

2011-01-01

419

Zinc oxide nanoparticles cause nephrotoxicity and kidney metabolism alterations in rats  

Microsoft Academic Search

Although zinc oxide nanoparticles (ZnO NPs) have been widely used, their potential hazards on mammalian and human remain largely unknown. In this study, the biochemical compositions of urine and kidney from the rats treated with ZnO NPs (100, 300 and 1000 mg\\/kg, respectively) were investigated using H nuclear magnetic resonance (NMR) technique with the pattern recognition of partial least squares-discriminant analysis.

Guangyan Yan; Yina Huang; Qian Bu; Lei Lv; Pengchi Deng; Jiaqing Zhou; Yanli Wang; Yanzhu Yang; Qiangqiang Liu; Xiaobo Cen; Yinglan Zhao

2012-01-01

420

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

421

Transparent and conductive aluminum doped zinc oxide films prepared by mid-frequency reactive magnetron sputtering  

Microsoft Academic Search

In this study, aluminum doped zinc oxide films were prepared by reactive mid-frequency (MF) magnetron sputtering (Leybold TwinMagTM) at deposition rate of approx. 9 nm\\/s and substrate temperature of 100 to 300°C. Process stabilization in the metallic mode was performed by the control of plasma impedance due to adjustment of oxygen flow. Metallic Zn:Al targets with different aluminum content were

B. Szyszka

1999-01-01

422

Mechanical properties and morphology of nylon 11\\/tetrapod-shaped zinc oxide whisker composite  

Microsoft Academic Search

Nylon 11\\/tetrapod-shaped zinc oxide whisker (T-ZnOw) composites were prepared via melt blending in a co-rotating twin-screw extruder. The mechanical properties, morphology and crystal structure were investigated. The tensile strength was increased by 15.7% as adding of 15phr T-ZnOw, while the optimum values of room temperature and low temperature (?40°C) notched Izod impact strength was increased by 281% and 65% as

Guosheng Hu; Yalin Ma; Biaobing Wang

2009-01-01

423

Low-Friction Coatings of Zinc Oxide Synthesized by Optimization of Crystal Preferred Orientation  

Microsoft Academic Search

The crystal preferred orientation of zinc oxide (ZnO) coatings on stainless steel substrates was precisely controlled by a\\u000a combinatorial sputter-coating system. ZnO coatings were analyzed by X-ray diffraction spectroscopy, and surface and interfacial\\u000a cutting analysis methods. The frictional properties of the coatings in a vacuum, the atmosphere, oil of n-hexadecane, and oil doped with palmitic acid molecules were observed. Different

Masahiro Goto; Akira Kasahara; Masahiro Tosa

424

Modeling and experimental study of nanoelectromechanical oscillator using single zinc oxide nanowire  

Microsoft Academic Search

This paper reports a novel nanoelectromechanical oscillator using a single zinc oxide (ZnO) nanowire suspended across two micromachined Au electrodes. The oscillator is self-driven into a motion that is self-detected by using a field effect transistor (FET) configuration and a lock-in detection method. A continuum electromechanical model is established to realize a theoretical analysis on the oscillator and the primary

R. Zhu; D. Q. Wang; S. Q. Xiang; Z. Y. Zhou; X. Y. Ye

2008-01-01

425

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

426

Quantitative trait analysis of the development of pulmonary tolerance to inhaled zinc oxide in mice  

Microsoft Academic Search

BACKGROUND: Individuals may develop tolerance to the induction of adverse pulmonary effects following repeated exposures to inhaled toxicants. Previously, we demonstrated that genetic background plays an important role in the development of pulmonary tolerance to inhaled zinc oxide (ZnO) in inbred mouse strains, as assessed by polymorphonuclear leukocytes (PMNs), macrophages, and total protein in bronchoalveolar lavage (BAL) phenotypes. The BALB\\/cByJ

Scott C Wesselkamper; Lung Chi Chen; Terry Gordon

2005-01-01

427

The repeated dose toxicity of a zinc oxide\\/hexachloroethane smoke  

Microsoft Academic Search

Mice, rats and guinea pigs were exposed to the smoke produced by ignition of a zinc oxide\\/hexachloroethane pyrotechnic composition, 1 h\\/day, 5 days\\/week, at three different dose levels, together with controls. The animals received 100 exposures except for the high dose guinea pigs, which underwent 15 exposures, because of high death rate during the first few days of exposure. The

T. C. Marrs; H. F. Colgrave; J. A. G. Edginton; R. F. R. Brown; N. L. Cross

1988-01-01

428

PULMONARY EFFECTS OF INHALED ZINC OXIDE IN HUMAN SUBJECTS, GUINEA PIGS, RATS, AND RABBITS  

Microsoft Academic Search

Occupational exposure to freshly formed zinc oxide (ZnO) particles (<1.0?µm aerodynamic diameter) produces a well-characterized response known as metal fume fever. An 8-hr threshold limit value (TLV) of 5?mg\\/m has been established to prevent adverse health effects because of exposure to ZnO fumes. Because animal toxicity studies have demonstrated pulmonary effects near the current TLV, the present study examined the

Terry Gordon; Lung Chi Chen; Jonathan M. Fine; Richard B. Schlesinger; Wei Yi Su; Tracy A. Kimmel; Mary O. Amdur

1992-01-01

429

Electrically Conductive Zinc Oxide (ZnO) Nanostructures Prepared by Sol-gel Spin-coating  

Microsoft Academic Search

The electrically conductive zinc oxide (ZnO) nanostructures prepared by sol-gel spin coating are presented. This project has been focused on electrical, optical and surface morphology properties of Al (aluminium) doped ZnO thin film. The effect of Al doping concentration at 0?5 at.% on the Al doped ZnO Thin film properties have been investigated. This project involves 3 processes which are

M. H. Mamat; A. S. Rodzi; M. Rusop

2011-01-01

430

Electrically Conductive Zinc Oxide (ZnO) Nanostructures Prepared by Sol-gel Spin-coating  

Microsoft Academic Search

The electrically conductive zinc oxide (ZnO) nanostructures prepared by sol-gel spin coating are presented. This project has been focused on electrical, optical and surface morphology properties of Al (aluminium) doped ZnO thin film. The effect of Al doping concentration at 0~5 at.% on the Al doped ZnO Thin film properties have been investigated. This project involves 3 processes which are

M. H. Mamat; A. S. Rodzi; M. Rusop

2011-01-01

431

Review of membrane separators and zinc-nickel oxide battery development  

SciTech Connect

After a discussion of membranes and their role in zinc-nickel oxide batteries, possible solutions are reviewed for problems related to membrane separators in these batteries. Experiments to characterize a membrane are also summarized. A bibliography is included to show what is being done in the field of battery research to develop practical membranes for use in Ni/Zn or Ag/Zn batteries. (LEW)

Bennion, D.N.

1980-10-01

432

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

433

Enhancement of LPG sensing properties in nanocrystalline zinc oxide thin film by high electronic excitation  

Microsoft Academic Search

We present an efficient detection of liquefied petroleum gas (LPG) using zinc oxide (ZnO) thin films irradiated with swift heavy ions (SHI) of 120MeV Au9+ ions. The nanostructured ZnO thin films on ITO glass substrates were synthesized using a simple, low cost, and efficient successive ionic layer adsorption and reaction (SILAR) technique. The as-synthesized thin films were annealed at 250°C

Ravikiran B. Birajadar; Arindam Ghosh; Anil Ghule; Fouran Singh; Ramphal Sharma

434

Effects of proton irradiation on indium zinc oxide-based thin-film transistors  

Microsoft Academic Search

In this research, we performed a high-dose proton-beam irradiation process to investigate the effect of irradiation on the performance of indium-doped zinc oxide-based thin-film transistors (IZO-TFTs) by controlling their electrical and structural properties. The resistivity of IZO thin films dramatically increased with increasing proton-irradiation doses up to ?1014cm?2, after which the resistivity recovered to a level similar to as-deposited IZO

Yeon-Keon Moon; Sih Lee; Dae-Yong Moon; Woong-Sun Kim; Byung-Woo Kang; Jong-Wan Park

2010-01-01

435

Tailoring of room temperature excitonic luminescence in sol–gel zinc oxide–silica nanocomposite films  

Microsoft Academic Search

Zinc oxide–silica (ZnO\\/SiO2=20:80, molar ratio) nanocomposites consisting of ZnO nanoparticles embedded in a dielectric matrix were prepared by a sol–gel technique (spin coating). Optical transmittance, Raman effect and photoluminescence measurements of the composites indicated effective capping of the ZnO nanoparticles (radii 1.4–1.5 nm) in the host showing practically no variation of particle size with the post-deposition-annealing treatments. The blue shift

S. Chakrabarti; D Das; D Ganguli; S Chaudhuri

2003-01-01

436

Electrically conductive zinc oxide (ZnO) nanostructures prepared by solgel spin-coating  

Microsoft Academic Search

The electrically conductive zinc oxide (ZnO) nanostructures prepared by sol-gel spin coating are presented. This project has been focused on electrical, optical and structural properties of Al doped ZnO thin film. The effects of Al doping concentration at 0~5 at.% on the Al doped ZnO thin film properties have been investigated. This project involves 3 processes which are thin film

M. H. Mamata; M. Rusop; Z. Zulkifli

2010-01-01

437

Well-crystallized zinc oxide quantum dots with narrow size distribution  

Microsoft Academic Search

In this study, pulsed laser ablation, online annealing, and following size classification using a differential mobility analyzer\\u000a (DMA) were employed to fabricate quantum dots (QDs) of zinc oxide (ZnO). The irregularly shaped ZnO particles were obtained\\u000a at annealing temperature less than 873 K, which gradually transformed into spherical QDs with increasing the annealing temperature.\\u000a Finally, ZnO QDs with narrow size distribution

Keigo Suzuki; Masashi Inoguchi; Keisuke Kageyama; Hiroshi Takagi; Yukio Sakabe

2009-01-01

438

Influence of some donor–acceptor couples on surface conductivity of aluminum doped zinc oxide  

Microsoft Academic Search

Zinc oxide is a wide-band semiconductor, which exhibits n-type conductivity that can be stabilised by using dopants pertaining to the third group b like Al3+. The conductivity of thick layers of doped material was tested in the presence of donor–acceptor couples, namely oxygen, water, CO and NO2 and their influence was related to the charge transfer reactions, which take place

M. Mezzanotte; R. Palombari

2005-01-01

439

Microstructural, magnetic and crystal field investigations of nanocrystalline Dy 3+ doped zinc oxide  

Microsoft Academic Search

Dy3+ doped zinc oxide was prepared by co-precipitation method. The as-prepared samples were annealed at different temperatures to obtain the samples with different particle sizes. The crystallographic phases of all the samples were confirmed by X-ray diffraction (XRD) patterns. Rietveld analysis of the XRD pattern of the sample annealed at 80°C showed that most of the Dy3+ ions were substituted

A. Bandyopadhyay; S. Modak; S. Acharya; A. K. Deb; P. K. Chakrabarti

2010-01-01

440

Fabrication and properties evaluation of aluminum and ruthenium co-doped zinc oxide thin films  

Microsoft Academic Search

Aluminum and ruthenium co-doped zinc oxide transparent conducting thin films were grown on polyethylene terephthalate substrate at 20°C by RF magnetron sputtering method. The structural and physical properties of the films were investigated with respect to variation of discharge power density. The XRD and FESEM results show that the film with 3.6W\\/cm2 power density has the best crystallinity and larger

Boen Houng; Chi Shiung Hsi; Bing Yi Hou; Shen Li Fu

2008-01-01

441

Thermal stability of polyacetal/ethylene-octene copolymer/zinc oxide nanocomposites  

NASA Astrophysics Data System (ADS)

In this work we investigate binary blends of polyoxymethylene and ethylene octene copolymer (EOC) and their composites with nanostructured zinc oxide (ZnO). EOC content in the composites varies from 0 to 50 wt. %. The amount of ZnO filler in the composites is changed in the interval from 0 to 5 wt. %. Thermal properties of composites are investigated with thermogravimetric analysis and differential scanning calorimetry. It is observed that ZnO addition increases thermal stability of the investigated composites.

Grigalovica, A.; Merijs Meri, R.; Zicans, J.; Ivanova, T.; Grabis, J.

2013-12-01

442

Performance Evaluation of Indium Zinc Oxide Thin Films for Flexible Organic Light-emitting Device Applications  

Microsoft Academic Search

In this report, high-quality indium zinc oxide (IZO) films (60-220 nm) were first grown on hardness poly-carbonate (HPC) substrate by ion-assisted deposition (IAD) dc magnetron sputtering without a post deposition annealing treatment. The electrical, optical, and structural properties of these films were investigated as a function of substrate temperature, oxygen pressure, and film thickness. IAD dc magnetron sputtering provides very

Chin-Ying Chen; Jyh-Jier Ho

2006-01-01

443

Deposition of zinc oxide thin films for application in bulk acoustic wave resonator  

Microsoft Academic Search

High quality piezoelectric zinc oxide (ZnO) thin films were deposited on (100)-oriented silicon substrate by reactive rf magnetron sputtering for bulk acoustic wave resonator. In order to improve the ZnO thin films quality, structural and electrical characteristics have been compared before and after annealing in helium (He) by X-ray diffraction and reflection coefficient S11 measurements. Scanning electron microscopy (SEM) was

G. Ferblantier; F. Mailly; R. Al Asmar; A. Foucaran; F. Pascal-Delannoy

2005-01-01

444

Studies on the mutagenicity of a zinc oxide-hexachloroethane smoke.  

PubMed

1. A suitable method has been developed for generating atmospheres of zinc oxide/hexachloroethane smoke (ZnHCE). 2. The smoke was investigated using the Ames test and the micronucleus assay. 3. It was weakly mutagenic to the bacteria, but in the bone marrow no increases in micronuclei were detected up to toxic levels of the smoke. 4. The method used here could be applied to other pyrotechnic mixtures which give rise to complex mixtures of products. PMID:1673625

Clode, S A; Riley, R A; Blowers, S D; Marrs, T C; Anderson, D

1991-01-01

445

First-principles study of zinc oxide honeycomb structures  

NASA Astrophysics Data System (ADS)

We present a first-principles study of the atomic, electronic, and magnetic properties of two-dimensional (2D), single and bilayer ZnO in honeycomb structure and its armchair and zigzag nanoribbons. In order to reveal the dimensionality effects, our study includes also bulk ZnO in wurtzite, zincblende, and hexagonal structures. The stability of 2D ZnO, its nanoribbons and flakes are analyzed by phonon frequency, as well as by finite temperature ab initio molecular-dynamics calculations. 2D ZnO in honeycomb structure and its armchair nanoribbons are nonmagnetic semiconductors but acquire net magnetic moment upon the creation of zinc-vacancy defect. Zigzag ZnO nanoribbons are ferromagnetic metals with spins localized at the oxygen atoms at the edges and have high spin polarization at the Fermi level. However, they change to nonmagnetic metal upon termination of their edges with hydrogen atoms. From the phonon calculations, the fourth acoustical mode specified as twisting mode is also revealed for armchair nanoribbon. Under tensile stress the nanoribbons are deformed elastically maintaining honeycomblike structure but yield at high strains. Beyond yielding point honeycomblike structure undergo a structural change and deform plastically by forming large polygons. The variation in the electronic and magnetic properties of these nanoribbons have been examined under strain. It appears that plastically deformed nanoribbons may offer a new class of materials with diverse properties.

Topsakal, M.; Cahangirov, S.; Bekaroglu, E.; Ciraci, S.

2009-12-01

446

Effects of morphology on photocatalytic performance of Zinc oxide nanostructures synthesized by rapid microwave irradiation methods  

NASA Astrophysics Data System (ADS)

In this study, two different chemical solution methods were used to synthesize Zinc oxide nanostructures via a simple and fast microwave assisted method. Afterwards, the photocatalytic performances of the produced ZnO powders were investigated using methylene blue (MB) photodegradation with UV lamp irradiation. The obtained ZnO nanostructures showed spherical and flower-like morphologies. The average crystallite size of the flower-like and spherical nanostructures were determined to be about 55 nm and 28 nm, respectively. X-ray diffraction (XRD), scanning electronic microscopy (SEM), Brunauer-Emmett-Teller (BET), room temperature photoluminescence (RT-PL) and UV-vis analysis were used for characterization of the synthesized ZnO powders. Using BET N2-adsorption technique, the specific surface area of the flower-like and spherical ZnO nanostructures were found to be 22.9 m2/gr and 98 m2/gr, respectively. Both morphologies show similar band gap values. Finally, our results depict that the efficiency of photocatalytic performance in the Zinc oxide nanostructures with spherical morphology is greater than that found in the flower-like Zinc oxide nanostructures as well as bulk ZnO.

Kajbafvala, Amir; Ghorbani, Hamed; Paravar, Asieh; Samberg, Joshua P.; Kajbafvala, Ehsan; Sadrnezhaad, S. K.

2012-04-01

447

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 reacti