Papers by Keyword: Room Temperature

Abstract: High-quality SnO₂ thin-film materials capable of detecting H₂S gas of low concentrations at room temperature was demonstrated in this paper. We employed aerosol-assisted chemical vapor deposition process for the deposition of SnO₂ thin films on alumina substrates with pre-patterned electrodes. The gas-sensing performances of the films prepared under different deposition conditions were systematically compared and analyzed. When SnCl₂·2H₂O was used as the precursor, a response sensitivity of 98.4 toward 50 ppm of H₂S at room temperature was achieved. At room temperatures, the resistance upon the H₂S gas exposure could recover to 90% of the initial resistance of the sensor when the H₂S gas flow was turned off.

Abstract: The silicon carbide thin film formation process, completely performed at room temperature, was developed by argon plasma and a chemical vapor deposition using monomethylsilane gas. Silicon-carbon bonds were found to exist in the obtained film, the surface of which could remain specular after exposure to hydrogen chloride gas at 800 oC. The silicon dangling bonds formed at the silicon surface by the argon plasma are considered to react with the monomethylsilane molecules at room temperature to produce the amorphous silicon carbide film.

Abstract: We have developed a new, simple, green and very reproducible aqueous synthesis method for the preparation of different sizes CdTe QDs without the use of any pyrophoric organometallic precursors. Transmission electron microscope image demonstrates the shape, monodispersity, average size and size distribution. Two different sizes CdTe QDs are mixed and standing for three months in aqueous solution. Through UV-Vis absorption spectroscopy and fluorescence spectrum detection, we confirm Ostwald ripening process can also occur in CdTe QDs mixed solution for a long time at room temperature.

Abstract: The quadratic orthogonal rotation design with 3 factors was used to study the effect of sodium hypochlorite, sodium sorbate and calcium propionate solutions on the chestnut, and to establish the function model with 3 factors. The analysis on this model showed that the order of the effect of 3 factors was as follows: Calcium propionate > Sodium sorbate >Sodium hypochlorite; In this test, for getting over 55% good-fruit rate, respectively, the optimum sodium hypochlorite concentration was 11.4％－19.5％, sodium sorbate concentration was 2.67％－39.9％, calcium propionate concentration was 1.09％－2.71％.

Abstract: The preparation and characteristics of ZnO(Zinc oxide) co-sputtered TaO (Ta oxide) electrodes(ZTO) grown on glass substrates using a specially designed composite target for use in organic solar cells are described. It was found that both the electrical and optical properties of the ZTO films were critically dependent on the Ar/O2 flow ratio and sputtering power. In addition, all ZTO electrodes show amorphous structure regardless of the Ar/O2 flow ratio, due to the low substrate temperature. We obtained the ZTO electrode with sheet resistance of 30 Ohm/square and average optical transmittance of 80% in room temperature. The conversion power efficiency by using ZTO electrode at optimized conditions is 2.6 %.

Abstract: Eight years ago recrystallization of OFE (oxygen-free electronic) copper was examined in detail using various techniques. In 2008 exactly the same material was measured using EBSD microscopy. The deformed state and fully recrystallized state have been analyzed and compared with data obtained eight years ago. The stored energy (SE) estimated by Image Quality (IQ) analysis was compared in these two cases. A significant amount of recovery took place in the sample, but only in some texture components. Some others present more or less the same SE as eight years ago. The textures of recrystallized samples were compared. We observed that the difference in SE distribution between the two deformed state has an influence on the final textures after recrystallization. Our study confirms the hypothesis that if a grain (orientation) has distinctly lower SE than other orientations - it has the highest growth preference (threshold hypothesis). Such grains (orientations) are dominant in the recrystallization texture.

Abstract: A rod-like liquid crystal (LC) N,N-(terephthalylidene) bis (4-n-butylaniline) (TB4A) was synthesized by one step at room temperature. The synthesized TB4A were investigated with nuclear magnetic resonance, fourier transform infrared spectrometer and ultraviolet-visible spectrophotometry, differential scanning calorimetry and polarizing optical microscopy. Our results demonstrated that the TB4A can form nematic, smectic A, smectic C, smectic F and smectic G LC phases.

Abstract: Effect of cationic polymer on granulation and COD removal efficiency in lab scale UASB reactors was examined, treating low-strength wastewater (COD 300-500mg l^-1) at room temperature. It was shown that cationic polymer was more effective for enhancing sludge granulation and COD removal efficiency as compared to the control experiment (without additives). After day 166 of operation, the amount of granules size above 0.5mm accounted for 32.1% of total sludge, higher than that of control experiment (19.3%). At 1.03 kg COD m^-3 d^-1 of OLR and 9.8 h of HRT, the effluent VFA had a maximum value of 168mg l^-1 and 240mg l^-1 in Reactor A and B respectively. The polymer-amended reactor took 36days to receive 1.44 kg COD m^-3 d^-1 of OLR at the 7.8 h of HRT, shorter than the control reactor (54days). The two reactors obtained above 80% in COD removal efficiency. It is shown that UASB reactor can also achieve higher COD removal treating low strength wastewater at room temperature.

Abstract: Magnesium alloys are poor in ductility at room temperature and it is known that the cold working is very difficult. Therefore, the development of forming methods, especially at normal temperature, is highly expected [1]. In this paper, AZ91 magnesium block were accelerated more than 100 m/s and the magnesium alloy was well deformed into the die gap. The cross-sectional microstructure was characterized and the deformation of the magnesium was discussed.

Abstract: A series of experiments were conducted to evaluate the feasibility that commercially pure titanium (CP-Ti) was pressed for multiple passes by equal channel angular pressing (ECAP) at room temperature. Samples of CP-Ti were processed at room temperature using the dies with channel angles of 90° and 120°, respectively. First, each billet was processed 4 passes by ECAP using a die with an angle of 120° and a ram speed of 0.5mm s-1. And in order to eliminate residual stress, immediate annealing at 473 K for an hour was conducted between two adjacent passes. Second, CP-Ti was successfully processed by ECAP for up to 8 passes using the same die and a ram speed of 2 mm s-1 by controlling the flow of metal. Finally, CP-Ti was successfully achieved using a conventional die with an angle of 90° between the channels at room temperature. Each billet was processed for two passes with a ram speed of 26 mm s-1. These experiments show that CP-Ti may be processed by ECAP at room temperature and special attention was paid on improvements in the yield stress, ultimate strength and micro-hardness of ECAPed-Ti that are slightly higher than the improvements attained after pressing at elevated temperatures.