Wyniki wyszukiwania - Biblioteka Nauki

1

Zinc oxide as a functional admixture to cement composites

100%

Klapiszewska I. , Ławniczak Ł. , Parus A. , Jesionowski T. , Klapiszewski Ł. , Ślosarczyk A.

Physicochemical Problems of Mineral Processing

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2022

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tom Vol. 58, iss. 2

art. no. 145565

EN

There is an increasing trend in the modern construction industry to use nanomaterials, which allow to improve the performance of construction materials on the one hand, and to shape new properties on the other. This study presents the results of physicomechanical and antibacterial tests for cement composites modified with zinc nanooxide. The main aim of this study was to compare the structural and morphological properties of three selected commercial zinc nanooxides and to determine the influence of the above mentioned nanooxides on the physicomechanical properties of cement composites and the ability to inhibit the activity of gram-positive and gram-negative bacteria as well as fungi. It was shown that commercial nanooxides can significantly differ in terms of physicochemical properties, which depend on their production method. Two of them were characterized by high specific surface areas, which in turn translated into rheological properties of cement mortars. Nanooxides with higher specific surface areas tend to reduce the plasticity of the mortars. According to the literature data, all nanooxides caused a delay in cement binder setting by more than 100%. This resulted in a reduction of the early one-day flexural and compressive strength of the composite. In the later curing period, especially after 7 days of hardening, a significant acceleration of the hydration process was observed in composites with the addition of all nanooxides, which was confirmed by significant increases in mechanical parameters. Nevertheless, the tested nanooxides showed different sensitivity towards microorganisms, which was influenced by both the type of nanooxide and bacteria.

2

ZnO dla fotowoltaiki

100%

Godlewski M. , Łuka G. , Pietruszka R. , Wachnicki Ł. , Witkowski B.

Prace Instytutu Elektrotechniki

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2014

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tom Z. 264

5-13

PL

Mimo znaczącej redukcji kosztów paneli fotowoltaicznych (PV), cena energii wytwarzanej przez baterie słoneczne ciągle jest za wysoka. Możliwe są dwie strategie rozwiązania tej sytuacji – (a) podniesienie wydajności konwersji światła w komórkach fotowoltaicznych lub/i (b) obniżenie kosztów paneli PV poprzez zastosowanie tańszych materiałów lub technologii. W referacie omówione są prace mające na celu: (a) zastąpienie zbyt drogiego ITO warstwami ZnO o przewodnictwie metalicznym, (b) uproszczenie konstrukcji komórek PV oraz (c) znalezienie alternatywnych materiałów.

EN

Despite of a large reductions of costs energy produced by solar panels is still too expensive. There are two approaches to change this situation: by (a) increase of device output and/or (b) reduction of device costs by use of cheaper alternative materials. In this article we discuss the latter approach – (a) replacement of ITO by ZnO with metallic conductivity, (b) change of device architecture, and (c) use of alternative materials.

3

Solution growth of ZnO sub-micro rods enhanced by electric field

100%

Pisarkiewicz T. , Kenig T. , Rydosz A. , Maziarz W.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2011

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tom Vol. 59, nr 4

425-428

EN

Recently the one-dimensional ZnO nanostructures have attracted much attention in gas sensor applications owing to their increased role of the surface. The authors have obtained ZnO rods of sub-micron size using the solution growth method with the growth temperature below 100.C. Investigations indicate that the rods have a well-defined hexagonal morphology and a wurtzite structure. The best uniformity and alignment of the sub-micron crystals was however obtained when electrodeposition from aqueous solution was developed. Sizes of these rods depend on the growth parameters. Moreover electrodeposition leads to a faster growth rate of ZnO sub-micron rods (2 hrs) as compared to the growth from solution (8 hrs). After electrodeposition the rods can be easily reoriented in external electric fields by using substrates with electrodes of appropriate geometry and configuration (dielectrophoretic effect). This enables the preparation of samples which can be used in gas sensor technology.

4

Investigations of highly conducting and transparent Sc doped ZnO films grown by the sol-gel process

100%

Sharma R. , Shishodia P. K. , Wakahara A. , Mehra R. M.

Materials Science Poland

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2009

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tom Vol. 27, No. 1

225--237

EN

Highly transparent and conductive scandium doped zinc oxide (ZnO/Sc) films were prepared on Corning glass 7059 substrates by the sol-gel technique. The influence of scandium concentration (0-1.5 wt. %) and annealing temperature (300-500 °C) on the structural, optical and electrical properties was investigated. The average transmittance was found to be above 89% in the visible region. ZnO/Sc film having 0.5 wt. % of Sc and annealed at 400 °C exhibited a minimum resistivity of 3.52×10-4 ohmocm. The surface morphology of these films examined by SEM and AFM revealed formation of nano rods.

5

Controllable synthesis of ZnO nanostructures by a simple solution route

100%

Wang J. , He S. , Zhang S. , Li Z. , Yang P. , Jing X. , Zhang M. , Jiang Z.

Materials Science Poland

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2009

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tom Vol. 27, No. 2

477--484

EN

Flower-shaped ZnO nanostructures, composed of ZnO nanorods, and sphere-shaped ZnO nanoclusters, composed of ZnO nanosheets, were synthesized by reacting zinc acetate dehydrate with sodium hydroxide and polyethylene glycol-20000 (PEG-20000) at 180 °C for 4 h in solution. The thickness of individual nanosheets is about 40-60 nm. The nanorods are of hexagonal shape with sharp tips, and have basic diameters of ca. 450-550 nm. The ZnO nanostructures were characterized by scanning electron microscropy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared, and Raman scattering measurements. The results demonstrated that the synthesized products are single crystalline with wurtzite hexagonal phase, the sphere-shaped ZnO grew in the [100] direction and the flower-shaped ZnO grew in the [001] direction.

6

Enhanced gas-sensing performance of Au-modified ZnO nanoparticles synthesized using bamboo cellulose as a template

100%

Li Y. , Zhao F.-X. , Lian X.-X.

Materials Science Poland

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2016

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tom Vol. 34, No. 4

708--714

EN

Au-modified ZnO (Au/ZnO) nanoparticles (NPs) synthesized using bamboo cellulose template and calcination process were characterized using X-ray diffraction, field-emission scanning electron microscopy, and transmission electron microscopy. The gas-sensing performance of Au/ZnO NPs based sensors was also examined. The results indicated that the Au/ZnO NPs exhibited enhanced gas-sensing performance compared with that of pure ZnO. The response of the Au/ZnO NPs to 100 ppm ethanol (50) at 240 °C was nearly 2.7 times higher than that to acetone (18.4) and approximately 12.5 times higher than that to benzene (4.1), carbon monoxide (1.6), hydrogen (1.6), and methane (1.8), respectively, which demonstrated their higher selectivity to ethanol versus other gases. This high response to ethanol could be attributed to the small size, Schottky barrier, and catalysis.

7

Chemical bath deposition and characterization of nanocrystalline ZnO thin films

100%

Kathalingam A. , Ambika N. , Kim M. R. , Elanchezhiyan J. , Chae Y. S. , Rhee J. K.

Materials Science Poland

|

2010

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tom Vol. 28, No. 2

514--522

EN

The subject of this paper is the wet chemical synthesis and characterization of nanocrystalline ZnO thin films. ZnO thin film was deposited on a zinc plate using a chemical bath of zinc acetate (Zn(O2CCH3)2) and ethylenediamine (C2N2H8) at various temperatures. Different substrates were used and their effect on the chemical bath deposition of ZnO were investigated. The effect of pH levels and temperature on the crystalline quality and morphology of the ZnO film are also presented.

8

Optical and electrical characterization of defects in zinc oxide thin films grown by atomic layer deposition

100%

Krajewski T. A. , Łuka G. , Wachnicki Ł. , Jakieła R. , Witkowski B. , Guziewicz E. , Godlewski M. , Huby N. , Tallarida G.

Optica Applicata

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2009

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tom Vol. 39, nr 4

865-874

EN

In the present paper, we discuss the influence of point defects on electrical and optical characteristics of ZnO thin films grown by the atomic layer deposition (ALD) method. The films were grown on glass substrates at low temperature (100-200 °C). We used diethylzinc (DEZn) and deionized water as precursors. Room temperature photoluminescence (RT PL) spectra, secondary ion mass spectroscopy (SIMS), electron dispersive X-ray (EDX) analysis and Hall effect measurements were made for as-grown ZnO layers and for the annealed ones (in air at 300 and 400 °C as well as in N2 atmosphere at 400 °C). The air-annealed ZnO films reveal a substantial reduction of a carrier concentration (up to 4 orders of magnitude - from 1019 to 1015 cm-3) combined with changes in intensity of the defect-related luminescence bands. PL related to deep defects is shifted towards the lower energy range (red light emission) after annealing (in air and nitrogen-rich conditions).

9

Otrzymywanie tlenku cynku z wodnych roztworów chlorku cynku i wodorotlenku potasu

100%

Kołodziejczak-Radzimska A. , Jesionowski T.

Przemysł Chemiczny

|

2010

|

tom T. 89, nr 9

1251-1256

10

In vitro evaluation of bioactivity of SiO2-CaO-P2O5-Na2O-CaF2-ZnO glass-ceramics

100%

Riaz M. , Zia R. , Saleemi F. , Bashir F. , Hossain T. , Kayani Z.

Materials Science Poland

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2014

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tom Vol. 32, No. 3

364--374

EN

Zinc is an essential trace element that stimulates bone formation but it is also known as an inhibitor of apatite crystal growth. In this work addition of ZnO to SiO2–CaO–P2O5–Na2O–CaF2 glass-ceramic system was made by conventional meltquenching technique. DSC curves showed that the addition of ZnO moved the endothermic and exothermic peaks to lower temperatures. X-ray diffraction analysis did not reveal any additional phase caused by ZnO addition and showed the presence of wollastonite and hydroxyapatite crystalline phases only in all the glass-ceramic samples. As bio-implant apatite forming ability is an essential condition, the surface reactivity of the prepared glass-ceramic specimens was studied in vitro in Kokubo’s simulated body fluid (SBF) [1] with ion concentration nearly equal to human blood plasma for 30 days at 37 °C under static condition. Atomic absorption spectroscopy (AAS) was used to study the changes in element concentrations in soaking solutions and XRD, FT-IR and SEM were used to elucidate surface properties of prepared glass-ceramics, which confirmed the formation of HCAp on the surface of all glass-ceramics. It was found that the addition of ZnO had a positive effect on bioactivity of glassceramics and made it a potential candidate for restoration of damaged bones.

11

Stability of ZnO nanofibers in processing liquid agents

100%

Stafiniak A. , Boratyński B. , Fronc K. , Elbaum D. , Paszkiewicz R. , Tłaczała M. , Baranowska-Korczyc A.

Materials Science Poland

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2013

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tom Vol. 31, No. 3

312--317

EN

The aim of the research was to determine the impact of developers, removers and solvents on the stability of ZnO nanofibers. Surface imaging of nanofiber morphology was studied using Scanning Electron Microscope. From the obtained results a set of factors which have the least inﬂuence on the etching of ZnO nanofibers during device processing was selected. The dependence of the grains size on the fibers robustness in the liquid solutions was investigated. It was found that the nanofibers calcinated at higher temperatures were more stable. This was due to the grain size of the fiber as the fibers calcinated at higher temperatures revealed larger grain size. The studies have shown that smaller grains were dissolved much faster, leaving the porous core of the ZnO nanofiber.

12

Grain growth kinetics for B2O3-doped ZnO ceramics

100%

Yuksel B. , Ozkan T. O.

Materials Science Poland

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2015

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tom Vol. 33, No. 2

220--229

EN

Grain growth kinetics in 0.1 to 2 mol % B2O3 -added ZnO ceramics was studied by using a simplified phenomenological grain growth kinetics equation Gn = K0 t exp(-Q/RT) together with the physical properties of sintered samples. The samples, prepared by conventional ceramics processing techniques, were sintered at temperatures between 1050 to 1250 °C for 1, 2, 3, 5 and 10 hours in air. The kinetic grain growth exponent value (n) and the activation energy for the grain growth of the 0.1 mol % B2O3 -doped ZnO ceramics were found to be 2.8 and 332 kJ/mol, respectively. By increasing B2O3 content to 1 mol %, the grain growth exponent value (n) and the activation energy decreased to 2 and 238 kJ/mol, respectively. The XRD study revealed the presence of a second phase, Zn3B2O6 formed when the B2O3 content was > 1 mol %. The formation of Zn3B2O6 phase gave rise to an increase of the grain growth kinetic exponent and the grain growth activation energy. The kinetic grain growth exponent value (n) and the activation energy for the grain growth of the 2 mol % B2O3 -doped ZnO ceramics were found to be 3 and 307 kJ/mol, respectively. This can be attributed to the second particle drag (pinning) mechanism in the liquid phase sintering.

13

Photonic structures with grating couplers based on ZnO

100%

Struk P. , Pustelny T. , Gołaszewska K. , Kamińska E. , Borysiewicz M. , Ekielski M. , Piotrowska A.

Opto-Electronics Review

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2011

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tom Vol. 19, No. 4

462-467

EN

The paper presents investigations concerning the design and realization of photonic structures with grating couplers. The first part of the paper deals with basic theoretical information on photonic structures with grating couplers and their appli- cation in optoelectronics. The further part presents the results of numerical investigations on photonic structures with grating couplers and shows the influence of geometrical parameters on the effectiveness of the input and output of optic power into and out of this photonic structure. The paper also provides the results of experimental investigations on a wideband gap semiconductor, viz. zinc oxide ZnO, as well as its application in planar waveguide structures and photonic structures with grating couplers.

14

Comparative study of ZnO layers prepared by PLD from different targets at various oxygen pressure levels

100%

HaÅ¡ko D. , Bruncko J. , Vincze A. , Uherek F. e.

Open Physics

|

2009

|

tom 7

|

nr 2

345-349

EN

Two series of polycrystalline zinc oxide (ZnO) layers, from Zn or ZnO targets, were grown on silicon (1 1 1) substrates by pulsed laser deposition (PLD) at ambient oxygen pressure levels, stepwise increased from 1 to 35 Pa. For ablation of targets, a pulsed Nd:YAG laser was used. The structural and morphological properties of the layers were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), and secondary ion mass spectrometry (SIMS). The SEM images of ZnO layers in SE mode show a uniform granular structure and modified surface morphology, depending on oxygen pressure. The mean grain size in height and lateral directions decreases with an increase of oxygen pressure from 1 to 5 Pa, while a subsequent rise of oxygen pressure from 5 to 35 Pa will cause an increase in the grain size. The AFM measurement revealed that the surface structures of zinc oxide layers grown from different targets were similar, and the layers formed at an ambient oxygen pressure of 5 Pa exhibited the smallest values of calculated roughness and granularity. SIMS depth profiling analyses confirmed that the ZnO composition was homogenous across the layer, up to the abrupt change of chemical composition at the interface between the ZnO layer and the Si substrate.

15

Preparation, structure and optical properties of transparent conducting gallium-doped zinc oxide thin films

100%

Gu J. H. , Lu Z. , Long L. , Zhong Z. Y. , Yang C. Y. , Hou J.

Materials Science Poland

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2015

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tom Vol. 33, No. 3

470--481

EN

Highly conductive gallium-doped zinc oxide (GZO) transparent thin films were deposited on glass substrates by RF magnetron sputtering. The deposited films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), four-point probe and UV-Vis spectrophotometer, respectively. The effect of growth temperature on the structure and optoelectrical properties of the films was investigated. The results demonstrate that high quality GZO films oriented with their crystallographic c-axis perpendicular to the substrates are obtained. The structure and optoelectrical properties of the films are highly dependent on the growth temperature. It is found that with increasing growth temperature, the average visible transmittance of the deposited films is enhanced and the residual stress in the thin films is obviously relaxed. The GZO films deposited at the growth temperature of 400 degrees C, which have the largest grain size (74.3 nm), the lowest electrical resistivity (1.31 x 10(-3) Omega.cm) and the maximum figure of merit (1.46 x 10(-2) Omega(-1)), exhibit the best optoelectrical properties. Furthermore, the optical properties of the deposited films were determined by the optical characterization methods and the optical energy-gaps were evaluated by extrapolation method. A blue shift of the optical energy gap is observed with an increase in the growth temperature.

16

Briquetting of EAF Dust for its Utilisation in Metallurgical Processes

100%

Magdziarz A. , Kuźnia M. , Bembenek M. , Gara P. , Hryniewicz M.

Chemical and Process Engineering

|

2015

|

tom 36

|

nr 2

263-271

EN

Dust generated at an electric arc furnace during steel production industry is still not a solved problem. Electric arc furnace dust (EAF) is a hazardous solid waste. Sintering of well-prepared briquetted mixtures in a shaft furnace is one of possible methods of EAFD utilisation. Simultaneously some metal oxides from exhaust gases can be separated. In this way, various metals are obtained, particularly zinc is recovered. As a result, zinc-free briquettes are received with high iron content which can be used in the steelmaking process. The purpose of the research was selecting the appropriate chemical composition of briquettes of the required strength and coke content necessary for the reduction of zinc oxide in a shaft furnace. Based on the results of the research the composition of the briquettes was selected. The best binder hydrated lime and sugar molasses and the range of proper moisture of mixture to receive briquettes of high mechanical strength were also chosen and tested. Additionally, in order to determine the thermal stability for the selected mixtures for briquetting thermal analysis was performed. A technological line of briquetting was developed to apply in a steelworks.

17

Influence of polysorbate 80 on the flotation of zinc oxide ores with amines

100%

Xie Q. , Wang D. , Han Z. , Tao H. , Liu S.

Physicochemical Problems of Mineral Processing

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2022

|

tom Vol. 58, iss. 1

149--158

EN

In this study, the influence of polysorbate 80 on zinc oxide flotation was investigated with an amine collector. The results indicated that the pretreatment of amines with polysorbate 80 enhanced the Zn grade and recovery obtained using zinc oxide flotation. Desliming prior to flotation is not suggested based on the results of this study. The appropriate temperature for flotation was as low as 8 °C, and this flotation method also could be applied to different types of zinc oxide ores. Under optimum flotation conditions, a concentrate with a Zn grade of 48.34% and a Zn recovery of 95.97% was obtained.

18

Photodegradation Kinetics of o-Nitroaniline (ONA), m-Nitroaniline (MNA), p-Nitroaniline (PNA), p-Bromoaniline (PBrA) and o-Chloroaniline (OCIA) in Aqueous Suspension of Zinc Oxide

100%

Habibi M. , Tangestaninejad S. , Khaledisardashti M.

Polish Journal of Chemistry

|

2004

|

tom Vol. 78 / nr 6

851-859

EN

Photodegradation of several aniline derivatives including o-nitroaniline (ONA), m-nitroaniline (MNA), p-nitroaniline (PNA), p-bromoaniline (PBrA) and o-chloroaniline (OClA) have been studied in aqueous solution using zinc oxide. Rate constants spane the range from 6.46×10-3 min-1 to 2.59×10-2 min-1. The slower degradation rate of p-bromoaniline (PBrA), 6.46×10-3 min-1 could be related to oxidation potential of the corresponding aromatic rings. The Langmuir-Hinshelwood (L-H) rate constant kr and adsorption constant, (KA) for all five aniline derivatives are reported.

19

Crystal growth of nanostructured zinc oxide nanorods from the seed layer

100%

Adetoye B. O. , Alabi A. B. , Akomolafe T. , Managutti P. B. , Coppede N. , Villani M. , Calestani D. , Zappetini A. , Maurizio C.

Materials Science Poland

|

2018

|

tom Vol. 36, No. 3

477--482

EN

One-dimensional (1D) zinc oxide (ZnO) nanostructures (nanorods) were synthesized on a glass slide and fluorine-doped tin oxide (SnO2/F or FTO) coated glass (FTO/glass) by a wet chemical method. The structural, morphological and optical analyses of the as-deposited ZnO nanostructures were performed by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and UV-Vis spectroscopy, respectively. The XRD results showed that the nanostructures as-deposited on the glass and the FTO/glass substrates were of ZnO wurtzite crystal structure, and the crystallite sizes estimated from the (0 0 2) planes were 60.832 nm and 64.876 nm, respectively. The SEM images showed the growth of densely oriented ZnO nanorods with a hexagonal-faceted morphology. The UV-Vis absorption spectrum revealed high absorbance properties in the ultraviolet range and low absorbance properties in the visible range. The optical energy band gap of the ZnO nanostructure was estimated to be 3.87 eV by the absorption spectrum fitting (ASF) method.

20

Microstructural study of MBE-grown ZnO film on GaN/sapphire (0001) substrate

100%

Li H. , Sang J. , Liu C. , Lu H. , Cao J.

Open Physics

|

2008

|

tom 6

|

nr 3

638-642

EN

Single crystalline ZnO film is grown on GaN/sapphire (0001) substrate by molecular beam epitaxy. Ga2O3 is introduced into the ZnO/GaN heterostructure intentionally by oxygen-plasma pre-exposure on the GaN surface prior to ZnO growth. The crystalline orientation and interfacial microstructure are characterized by X-ray diffraction and transmission electron microscopy. X-ray diffraction analysis shows strong c-axis preferred orientation of the ZnO film. Cross-sectional transmission electron microscope images reveal that an additional phase is formed at the interface of ZnO/GaN. Through a comparison of diffraction patterns, we confirm that the interface layer is monoclinic Ga2O3 and the main epitaxial relationship should be $$ (0001)_{ZnO} \parallel (001)_{Ga_2 O_3 } \parallel (0001)_{GaN} $$ and $$ [2 - 1 - 10]_{ZnO} \parallel [010]_{Ga_2 O_3 } \parallel [2 - 1 - 10]_{GaN} $$.