bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of precursor concentration on the structural and optical properties of ZnO nanostructures
Authors: Kamaruddin Sharul Ashikin , Sahdan Mohd Zainizan , Chan Kah‐Yoong , Rusop Mohamad , Saim Hashim 
Published: May 2010

AbstractZinc oxide (ZnO) is an emerging material in large area electronic applications such as thin‐film solar cells and transistors. We report on the fabrication and characterization of ZnO nanostructures. ZnO nanostructures have been synthesized using sol–gel immerse technique on oxidized silicon substrates. Different precursor's concentrations ranging from 0.0001 to 0.01 M using zinc nitrate hexahydrate [Zn(NO3)2.6H2O] and hexamethylenetetramine [C6H12N4] has been employed in the synthesis of ZnO nanostructures. The surface morphologies were examined using scanning electron microscope (SEM) and atomic force microscopy (AFM). In order to investigate the structural properties, the ZnO nanostructures were measured using X‐ray diffractometer (XRD). The optical properties of the ZnO nanostructures were measured using photoluminescence (PL) spectrometer.
Optimization of the contact resistance in the interface structure of n‐type Al/a‐SiC:H by thermal annealing for optoelectronics applications
Authors: Ambrosio Roberto , Torres Alfonso , Zuñiga Carlos , Moreno Mario , Mireles Jose 
Published: May 2010

AbstractThe presented work meets the requirements for integration of amorphous silicon carbon films with silicon technology in order to obtain a complete optoelectronic system such as light emitting diodes and its electronic readout circuits. The key enabler for this integration scheme is the low temperature of deposition of a‐SiC:H films and an ohmic behavior in the interface metal/a‐SiC:H. In this work, the optimization of the interface Al/a‐SiC:H films are performed by means of thermal annealing timing. The a‐SiC:H films were deposited by enhanced chemical vapor deposition from CH4/SiH4 and C2H2/SiH4 mixtures. The structural and optical properties of the deposited films are presented. An implantation phosphorous dose was used for doping before fabrication of patterned aluminum contacts. The implanted films were electrically characterized by the transfer length method (TLM) measuring a sheet resistance value as low as 171 MΩ/square. The Schottky behavior was improved to ohmic behavior after several hours in thermal annealing treatments at 350 °C, which allows to obtain a reasonable contact resistance values in the range from 8.6 to 26.8 kΩ.
Preparation of ZnO thin film by the sol–gel method using low temperature ozone oxidation
Authors: Ehara Takashi , Ueno Takaaki , Abe Junya 
Published: May 2010

AbstractZinc oxide thin films have been prepared by the sol–gel method from a 2‐methoxyethanol solution of zinc acetate dihydrate on SiO2 substrates using air, pure oxygen, and 1% ozone in oxygen as oxygen source. In the cases where air or oxygen was used as the oxygen source for thermal annealing, samples annealed at 600 to 800 °C exhibit a (0002) peak in X‐ray diffraction (XRD). A sample annealed at 700 °C exhibited the highest (0002) peak intensity in conventional thermal annealing. However, the case using 1% ozone in oxygen as the atmosphere presented different results. A sample treated in 1% ozone at 100 °C had peak intensity in XRD (0002) comparable with samples annealed at several hundreds of degree in air or oxygen. This result indicates that the high oxidation efficiency of ozone is useful in decreasing the processing temperature of the sol–gel method.
InGaZnO thin‐film transistors with YHfZnO gate insulator by solution process
Authors: Kim Si Joon , Kim Gun Hee , Kim Dong Lim , Kim Doo Na , Kim Hyun Jae 
Published: May 2010

AbstractThin‐film transistors (TFTs) with the indium gallium zinc oxide (IGZO) as a channel layer and the yttrium hafnium zinc oxide (YHZO) as a gate insulator layer were fabricated and both of layers were deposited by solution process. YHZO solution was prepared by dissolving yttrium nitrate, hafnium chloride, and zinc acetate into 2‐methoxyethanol with additional stabilizers. The spin coating and annealing procedures were repeated several times to obtain sufficient thickness for gate insulator in IGZO TFTs. The electrical characteristics of YHZO films were analyzed by capacitance–voltage and leakage current measurements. The dielectric constant was about 16.4 and leakage current density was about 6 × 10−8 A/cm2. In solution‐processed IGZO TFTs with YHZO gate insulator, the field effect mobility, the on‐to‐off current ratio, the threshold voltage, and the subthreshold swing were 0.29 cm2/Vs, ∼105, 3.47 V, and 1.26 V/decade, respectively.
The optical absorption of metal nanoparticles deposited on ZnO films
Authors: Remes Z. , Kromka A. , Vanecek M. , Babcenko O. , Stuchlikova T.‐H. , Cervenka J. , Hruska K. , Trung T. Q. 
Published: May 2010

AbstractWe present the optical absorption spectra of metal nanoparticles prepared by thermal annealing of the ultra thin metal films evaporated on polycrystalline ZnO films. The surface morphology, particle size and density were monitored by the atomic force microscopy (AFM) and scanning electron microscopy (SEM). ZnO films with the surface roughness about 10 nm rms deposited on sapphire and immersed in the transparent liquid show negligible optical reflectance, interferences and light scattering and are transparent at wavelengths above 400 nm. The optical absorption of ZnO film in UV region allows to calibrate the photothermal deflection spectra (PDS) both with and without metal nanoparticles and to estimate with high precision the optical absorptance of metal nanoparticles in the visible and near infrared region. The optical absorptance spectra of gold nanoparticles embedded in the non‐absorbing medium can be simulated by effective medium approximation‐EMA (Maxwell‐Garnett model). The maximum of the localized plasmon resonance shifts to longer wavelengths (red shift) when the metal nanoparticles are more tightly packed in the matrix, whereas the size of the nanoparticles determinate the width of the resonance peak. The electron scattering cross section of Au nanoparticles observed by SEM is about two times larger than their diameter.
Hybrid polymer/TiO2 films by in situ hydrolysis condensation of titanium alkoxide precursors for photovoltaic transparent windows
Authors: Davenas Joël , Barlier Vincent , Legaré Véronique‐Bounor , Canut Bruno , Rybak Andrzej , Slazak Agnieszka , Jung Jaroslaw 
Published: May 2010

AbstractPoly(vinylcarbazole)/TiO2 hybrid thin films have been produced by the hydrolysis condensation of titanium alkoxide precursors dispersed in a polymer layer deposited on ITO substrates. Common alkoxide precursors like titanium isopropoxide [Ti(iOPr)4] show a fast hydrolysis beginning during film deposition, which leads to early phase separation. A new TiO2 precursor precursor bearing carbazole groups: titanium tetrakis 9H‐carbazole‐9‐yl‐ethyl‐oxy [Ti(OeCarb)4] has been used to slow down the reactivity of the precursor by a steric hindrance effect. Improved precursor dispersion in the polymer solution is obtained for this new precursor leading to an homogeneous dispersion of the TiO2 phase at the nanoscale in the hybrid film. Rutherford Backscattering Spectrometry has shown that the hydrolysis condensation was effective with the production of carbazol alcohol remaining trapped in the bulk of the film. This residual alcohol leads to an increase of the UV optical absorption of the PVK/TiO2 hybrid films. Improvement of the balance between the two types of photogenerated charges has been shown by surface potential decay experiments upon the formation of a TiO2 conduction network for the transport of electrons. The film is almost transparent above 350 nm opening a new route for the elaboration of semi‐transparent photovoltaic glasses, which can find application on the growing market of energy efficient buildings.
Hydrogen sensing performance dependence on catalytic metal thickness of Pt/AlGaN/GaN Schottky diodes
Authors: Song Junghui , Lu Wu 
Published: May 2010

AbstractThe dependence of catalytic metal thickness in Pt/AlGaN/GaN heterostructure Schottky diodes for high temperature hydrogen sensing is investigated. The decrease of Pt catalytic film thickness at the diodes enhances both the hydrogen sensitivity and the detection limit. As Pt film thickness decreases from 40 nm to 2.5 nm, the H2 detection limit improves from 100 ppb to 60 ppb at 25 °C and the sensitivity increases two to three times over the range of temperature from 25 °C to 500 °C and H concentration from 10 ppb to 5000 ppm. The effect of Pt thickness on the device current modulation by H2 is dependent only on the Schottky barrier height change (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of furostanol glycosides fromTrigonella foenum‐graecumon the reproductive system of male albino rats
Authors: Aswar Urmila , Bodhankar Subhash Laxman , Mohan V. , Thakurdesai Prasad Arvind 
Published: June 2010

AbstractTrigonella foenum(TF) has long been used in the traditional Indian systems of medicine for the treatment of various ailments. The objective was to study the anabolic and androgenic activity of the furostanol glycosides fraction ofTrigonella foenum‐graecum(Fenu‐FG) in immature castrated male Wistar rats. It was also aimed to investigate the effect of Fenu‐FG on testicular histology in non‐castrated immature rats. The animals (55 ± 5 g) were castrated. The rats were treated with either vehicle, testosterone (10 mg/kg s.c. bi‐weekly) or Fenu‐FG (10 and 35 mg/kg p.o.) once daily for 4 weeks. At the end of the study, blood was withdrawn, serum testosterone and BUN were measured. Animals were killed and reproductive organs were excised and weighed.Fenu‐FG (35 mg/kg p.o.) and testosterone (10 mg/kg, s.c. biweekly) increased the weight of the levator ani muscle as well as body weight. Fenu‐FG (10 or 35 mg/kg p.o.) did not change the testosterone level in castrated rats. Histopathological examination of the testis of non‐castrated rats treated with Fenu‐FG (10, 35 mg/kg p.o.) showed normal architecture of the testis. Fenu‐FG (35 mg/kg p.o.) showed anabolic activity without androgenic activity. Copyright © 2010 John Wiley & Sons, Ltd.
α‐glucosidase inhibition and the in vivo hypoglycemic effect of butyl‐isobutyl‐phthalate derived from the Laminaria japonica rhizoid
Authors: Bu Tong , Liu Ming , Zheng Lanhong , Guo Yuewei , Lin Xiukun 
Published: June 2010

AbstractThe rhizoid of Laminaria japonica is widely used in Chinese medicine as a treatment for diabetes. Therefore, a bioactivity‐tailored isolation and detailed chemical characterization was used to identify the antidiabetes compounds found in the L. japonica rhizoid. Liquid chromatography/mass spectrometry (LC/MS), proton NMR and carbon NMR spectra analyses demonstrated that the active compound was butyl‐isobutyl‐phthalate (BIP). BIP demonstrated a significant concentration‐dependent, non‐competitive inhibitory activity against α‐glucosidase in vitro, with an IC50 of 38 μm. In vivo, the ethyl acetate fraction (EAF) and purified BIP displayed a significant hypoglycemic effect in streptozocin‐induced diabetic mice. The present study indicates BIP could be considered as an α‐glucosidase inhibitor and developed as an important antidiabetes agent for type II diabetes therapy. Copyright © 2010 John Wiley & Sons, Ltd.
The Effect of propolis on Th1/Th2 cytokine expression and production by melanoma‐bearing mice submitted to stress
Authors: Missima F. , Pagliarone A. C. , Orsatti C. L. , Araújo J. P. , Sforcin J. M. 
Published: June 2010

AbstractSince propolis possesses immunomodulatory and antitumoral activities, this work aimed to evaluate its effect on Th1 (IL‐2 and IFN‐γ) and Th2 (IL‐4 and IL‐10) cytokines mRNA expression and production by melanoma‐bearing mice submitted to immobilization stress. C57BL/6 male mice were inoculated with B16F10 cells, treated with propolis and submitted to stress for 14 days. Spleen cells were assessed for Th1/Th2 cytokine expression and production. Stress induced a higher tumor area, while propolis‐treated mice, stressed or not, showed a melanoma development similar to the control. In groups without melanoma, stress or propolis treatment did not affect IL‐2, IL‐4 and IL‐10 gene expression. On the other hand, IL‐2 and IL‐10 expression was inhibited in melanoma‐bearing mice, stressed or not. Th1 cytokine production was also inhibited in melanoma‐bearing mice. Propolis administration to melanoma‐bearing mice submitted to stress stimulated IL‐2 expression, as well as Th1 cytokine (IL‐2 and IFN‐γ) production, indicating the activation of antitumor cell‐mediated immunity. Propolis also stimulated IL‐10 expression and production, which may be related to immunoregulatory effects. The data indicate that propolis exerted an immunomodulatory activity in this assay, which may be related to its antitumoral action in vivo. Copyright © 2010 John Wiley & Sons, Ltd.
Artificial neural network application of modeling failure rate for Boeing 737 tires
Authors: Al‐Garni Ahmed Z. , Jamal Ahmad 
Published: June 2010

AbstractThis paper presents an application of artificial neural network (ANN) technique for conducting the reliability analysis of Boeing 737 tires. For this purpose, an ANN model utilizing the feed‐forward back‐propagation algorithm as a learning rule is developed. The inputs to the neural network are the flight operational time and the number of landings as independent variables and the output is the failure rate of the tires. Two years of data are used for failure rate prediction model and validation. Model validation, which reflects the suitability of the model for future predictions, is performed by comparing the predictions of the model with that of Weibull regression model. The results show that the failure rate predicted by the ANN is closer in agreement with the actual data than the failure rate predicted by the Weibull model. The present work also identifies some of the common tire failures and presents representative results based on the established model for the most frequently occurring tire failure. Copyright © 2010 John Wiley & Sons, Ltd.
Impoverishment of YOY‐fish assemblages by intense commercial navigation in a large Lowland river
Authors: Huckstorf V. , Lewin W.‐C. , Mehner T. , Wolter C. 
Published: June 2010

AbstractNavigation‐induced physical forces have been suggested to modify the structure of riverine fish assemblages by impeding especially the recruitment of littoral bound species. To investigate the effect of vessel frequency on fish, we compared the composition and seasonal succession of young‐of‐the‐year (YOY) fish assemblages in three similarly degraded river reaches differing in average vessel passages (2, 6 and 41 per day). Fish were caught by electrofishing biweekly between May and September.Multivariate tests were used to analyse differences between YOY‐fish assemblages and hurdle regression models applied to determine abiotic factors predicting fish occurrence and abundance. Roach (Rutilus rutilus) and perch (Perca fluviatilis) densities were compared. Roach larvae remain in the littoral zone while perch larvae shift to the pelagic zone immediately after hatch. YOY‐fish assemblage structure substantially changed along the traffic intensity gradient. In the high traffic intensity reach, species number and total fish density were markedly reduced compared to the other reaches. Roach densities were lowest in the high traffic intensity reach whereas perch densities did not decline along the gradient. Hurdle regressions confirmed a stronger effect of commercial navigation traffic intensity on roach than on perch. The total zooplankton biomass was highest in the high traffic intensity reach.Our results provide empirical evidence that intensive commercial navigation impoverishes fish assemblages in width‐restricted waterways. They underlined that in particular those species that have their first nursery habitats in shoreline areas were more affected by intensive commercial navigation than species whose larvae live predominantly pelagic. The results indicate that the negative effect of intensive navigation on riverine fish results primarily from the navigation‐induced hydraulic disturbances along the banks. Therefore, mitigation of navigation‐induced hydraulic forces is required to prevent degradation of fish communities in waterways. Copyright © 2010 John Wiley & Sons, Ltd.
Depth profiling of lamella‐phase diblock copolymers using SIMS
Authors: Lee Yeonhee , Lee Jihye , Lim Weon Cheol , Shin Kwanwoo , Kim Kang‐Jin 
Published: June 2010

AbstractThe morphology from symmetric diblock copolymers of poly(styrene‐b‐propylmethacrylate) (PS‐PPrMA), where polystyrene (PS) block was perdeuterated near the copolymer/air and copolymer/substrate interfaces and in the bulk, was characterized by using time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS). Elemental depth profiles measured in the negative ion mode by a Cs+ primary ion beam demonstrate variations in hydrogen, deuterium, carbon, oxygen and hydrocarbons within the diblock copolymer according to the depth. The annealed deuterated poly(styrene‐b‐propylmethacrylate) (dPS‐PPrMA) copolymer samples showed a decrease in the deuterated PS secondary ion peak intensity as compared to the as‐cast samples. TOF‐SIMS depth profiling was obtained for the lamellar morphology of dPS‐PPrMA which is found to orient parallel to the surface of the substrate. This preferential orientation resulted in a periodic variation in the composition of each block that continued through the entire copolymer film with thickness of 700 and 2100 Å. Temperature‐dependent annealing studies on dPS‐PPrMA thin film on the silicon substrates were performed to investigate the lower critical ordering transition (LCOT) properties of diblock copolymers. Copyright © 2010 John Wiley & Sons, Ltd.
Surface hydrophilization of SU‐8 by plasma and wet chemical processes
Authors: Walther Ferdinand , Drobek Tanja , Gigler Alexander M. , Hennemeyer Marc , Kaiser Michael , Herberg Helmut , Shimitsu Tetsuji , Morfill Gregor E. , Stark Robert W. 
Published: June 2010

AbstractWetting properties and surface roughness of SU‐8 can be modified by wet chemical and plasma processes. These processes result in an enhanced wettability that can be attributed to an increase of CO and COO groups at the surface. Wet chemical etching with ceric ammonium nitrate (CAN) rendered the SU‐8 surface hydrophilic. However, it also led to the accumulation of cerium species on the surface, which may interfere with biochemical reactions in the device. Surface activation could also be achieved with a low‐temperature atmospheric argon plasma, which left a smooth surface. Treatment of SU‐8 with oxygen plasma led to a stable hydrophilization and an increased surface roughness. Owing to oxygen plasma processing, antimony species were accumulated which could be removed with a cleaning step. In order to maintain the hydrophilization after oxygen plasma treatment for storage, or over several wetting cycles, the surface can be coated with a protein‐resistant graft copolymer (PLL‐g‐PEG). Copyright © 2010 John Wiley & Sons, Ltd.
Comparison of Bi1+, Bi3+ and C60+ primary ion sources for ToF‐SIMS imaging of patterned protein samples
Authors: Dubey Manish , Brison Jérémy , Grainger David W. , Castner David G. 
Published: June 2010

AbstractImaging time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) has been used to study protein bound to a photolithographically patterned, commercial poly(ethylene glycol) (PEG)‐based polymer film. The effect of different ion sources on the fragmentation pattern from this sample was analyzed with respect to the surface sensitivity of characteristic protein fragments and contrast in the ion images. The method demonstrates that, under similar fluence (below the static limit), Bi3+ provides better surface sensitivity for low mass fragments, and the best image contrast, as compared to Bi1+ and C60+ ion sources. Principal component analysis (PCA) was utilized to process depth profiles for this sample and shows that a primary ion fluence of approximately 20 × 1012 ions/cm2 is required to etch through the adsorbed protein layer. Copyright © 2010 John Wiley & Sons, Ltd.
Quantitative analysis of the surface composition of mixed self‐assembled monolayers using ToF‐SIMS and FT‐IR analyses
Authors: Min Hyegeun , Yu Hyunung , Son Miyoung , Moon Dae Won , Lee Tae Geol 
Published: June 2010

AbstractMixed self‐assembled monolayers (SAMs) consisting of different molecules have been used to modify surface wettability, functionalize end groups for chemical binding, and control adsorption of proteins, DNA, or cells. In these applications, control over the quantification of the surface composition of a mixed SAM is especially important when designing biochips and biosensors. Previously, we presented a method by which ToF‐SIMS can be used to quantify the composition of two adsorbates with acetylene and propene functional groups from their secondary ion yield ratio in mixed SAMs on gold substrates. We concluded that although the ion yield ratio of the two adsorbates in mixed SAM was not equal to the mole fraction of Diyne (‐acetylene) and Diene (‐propene) in a solution, this was due to a different secondary ion formation, and not to the difference in the amount of adsorbates on the surface. In this study, we revisit the same sample system, this time applying a FT‐IR technique to test the accuracy of our previous findings. We found that the absorbances of the acetylene and propene functional groups neatly and linearly correlated with the mole fraction in the solution, which were consistent with our previous conclusions. We also used this methodology to quantify mixed silane SAMs on a silica surface. Our study shows that the ToF‐SIMS and FT‐IR techniques can complement one another and be useful to quantify mixed SAMs on various substrates. Copyright © 2010 John Wiley & Sons, Ltd.
Protection of magnesium alloy weldment using arc‐sprayed aluminum coatings and its postheat treatment
Authors: Liu Liming , Xu Rongzheng 
Published: June 2010

AbstractArc‐sprayed Al coatings and its postheat treatment are applied to Mg alloy weld joints to improve its corrosion resistance. Effects of postheat treatment on the corrosion character of coating, tensile strength of weld joints, and adhesive strength between coating and weld joint are studied. The research results show that arc‐sprayed Al coatings are successfully deposited on the surface of the Mg alloy weld joint by arc spraying technology. The coating is mechanically bonded to the weld joint. But after a postheat treatment, the coating and the joint are metallurgically bonded due to the formation of AlMg intermetallic compounds diffusion layer. At the same time, the corrosion resistance of Al‐coated Mg alloy weldment with PHT is higher than without PHT. In addition, the tensile strength of the weld joint is hardly affected by the postheat treatment. Copyright © 2010 John Wiley & Sons, Ltd.