• Journal of the Korean Vacuum Society
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• v.5 no.2
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• pp.119-126
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• 1996

The effect of the $O_2$ concentration in the sputtering gas mixture, substate temperature and Ar pressure on the structural and optical properties of 3 mol% YSZ and 8 mol% YSZ thin films deposited by RF magnetron sputtering were investigated . The films were observed to have various crystal structures with different compositions in accordance with the type of the target materials. The size of fine grain-like particles decreased wiht increasing the $O_2$ concentration in the sputtering gas in the case of 3mol% YSZ, while it increased in the case of 8 mol% YSZ . However, the average opticla transmission of 8mol% YSZ, despite of thicker thickness. was higher than that of 3 mol% YSZ. Furthermore, the values of refractive index of 3mol% YSZ increased with increasing the $O_2$ concentration in the sputtering gas on the contrary to those of the 8 mol% YSZ. However, the transmission spectra of 8 mol% YSZ films were not strongly influenced by the substrate temperature and Ar pressure, whereas the refractive index of the YSZ films were strongly affected by the sputtering parameters.

• Journal of the Korean Ceramic Society
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• v.40 no.11
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• pp.1113-1119
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• 2003

We used isopropanol which has low boiling point to prepare thin films at low temperature and changed mole concentration of zinc acetate from 0.3 to 1.3 mol/l. The structural, optical and electrical properties of ZnO thin films with Zn content were investigated. ZnO thin films highly oriented along the c-axis were obtained at Zn concentration of 0.7 mol/l. ZnO thin films with Zn concentration of 0.7 mol/l showed a homogeneous surface layer of nano structure. The transmittance of ZnO thin films by UV-vis. measurement was about 87% under the Zn concentration of 0.7 mol/l, but rapidly decreased over the 1.0 mol/l. The optical band gap energy was obtained from 3.07 to 3.22 eV which is very close to the band gap of bulk ZnO (3.2 eV). The electrical resistivity of ZnO thin films was about 150 $\Omega$-cm that shows little difference with Zn concentration. I-V curves of ZnO thin films exhibited typical ohmic contact properties.

• Journal of the Korean Ceramic Society
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• v.30 no.10
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• pp.791-796
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• 1993

The electro-magnetic properties of the Mn-Zn ferrite single crystal with small variation of Fe2O3 concentration at the high permeability composition, 53mol% Fe2O3-28.5mol% MnO-18.5mol% ZnO, have been studied for the VCR magnetic head application. With the increase of the Fe2O3 concentration, the Fe2+ concentration increased, the specific resistivity decreased, the secondary maximum permeability shifted to the lower temperature, and the initial permeability decreased. It was concluded that the small variation of $\pm$0.5mol% Fe2O3 concentration greatly affected the electro-magnetic properties of Mn-Zn ferrite single crystals. At the composition of 53mol% Fe2O3, the initial permeability was comparatively high (650 at 5MHz) and its temperature dependence was small.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.3
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• pp.11-17
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• 2015

In acid hydrolysis process of biomass saccharification. neutralization of acid hydrolyzate is essential step, which resulted in dissolved cations in glucose solution. Impact of cations to Kluyveromyces marxianus in glucose solution was investigated focused on ethanol fermentation. Either potassium or sodium cations decreased the ethanol fermentation and glucose to ethanol conversion. Glucose consumption by K. marxianus was delayed by increasing potassium cation concentration as completely consumed within 12 h in potassium cation 0.46 mol and 0.92 mol but within 24 h in potassium cation 1.38 mol. Also, ethanol fermentation process was slowed down with increasing concentration of the potassium sulfate. Fermentation of glucose solution to ethanol was more inhibited by sodium cation than potassium cation in glucose solution. Glucose was completely consumed within 24 h in sodium cation 0.95 mol. but at 1.90 mol or 2.84 mol in sodium cation could not finish the fermentation within 48 hour. Ethanol concentration was 22.26 g/L at low sodium cation in glucose solution with complete fermentation within 24 h. With increasing sodium cation in glucose solution, final ethanol concentration was reached at 14.10 g/L (sodium cation con) and 0.21 g/L (sodium cation con), which meant delaying of fermentation by sodium cations.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.3
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• pp.185-191
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• 2014

In this paper, absorption and reaction characteristics of low $CO_2$ and alkanolamines were investigated. As MEA concentrations increase 1, 2 and 3 wt%, $CO_2$ loadings decrease 0.34 mol-$CO_2/mol$-absorbent, 0.32 mol-$CO_2/mol$-absorbent and 0.3 mol-$CO_2/mol$-absorbent, respectively. Also, $CO_2$ loadings decrease from 0.32 mol-$CO_2/mol$-absorbent, 0.30 mol-$CO_2/mol$-absorbent and 0.28 mol-$CO_2/mol$-absorbent as AMP concentrations increase 1, 2 and 3 wt%. Experimental results with blending solutions show that $CO_2$ loading was the highest, 0.52 mol-$CO_2/mol$-absorbent, when 0.5 wt% MEA and 0.5 wt% AMP were blended.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.2
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• pp.87-95
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• 1996

We have studied the effects of La concentration on the optical and electrical properties of lead lanthanum titanate (PLT) thin films by using sol-gel method. Both the optical and electrical properties are greatly affected by the La concentration. The refreactiv eindices of the films varied from 2.23 to 1.93 with varying La concentration in the range from 15 to 33 mol%. The dielectric constants of the films vary form 340 to 870 with varying La concentration in the range form 15 to 33 mol%. Hysteresis loop becomes slimmer with the increase of La concentration form 15 to 28mol% and little fatter again with the increase of La concentration form 28 to 33 mol%. Among the films investigated in this research, PLT(28) thin film shows the best dielectric properties for the application to the dielectrics of ULSI DRAM's. At the frequency of 100Hz, the dielectric constant and the loss tangent of PLT(28) thin films are 940 and 0.08 respectively. Its leakage current density at 1.5${\times}10^{5}$V/cm is 1${\times}10^{-6}A/cm^{2}$. The comparision between the simulated and the experimental curves for the switching transient characteristics shows that PLT (28) thin films behaves like normal dielectrics.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.9
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• pp.911-916
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• 2006

The influence of substrate concentration and hydraulic retention time(HRT) on the hydrogen production by anaerobic microflora was investigated by conducting three series of continuous experiments the individual influences of substrate concentration and HRT. In series I, substrate concentration was increased from 3 to 27 g-glucose/L keeping HRT at 8 hr. Series II and III carried out same condition with series I at HRT of 16 hr and 24 hr, respectively. The effects of HRT and substrate concentration on the hydrogen production yield were analyzed by quadratic model. The maximum hydrogen production yield of 2.05 mol $H_2/mol$ glucose was found at the HRT of 9.6 hr and the substrate concentration of 15.4 g/L. The relationship between HRT and substrate concentration on hydrogen production yield as displayed a saddle shape in the response surface plot. Optimum HRT and substrate concentration are observed at in the range of 5 and 14 hr, at between 13 and 17 g/L, respectively, for the hydrogen production yield being 2 mol $H_2/mol$ glucose. The concentrations of organic acids increased with the increase of the amount of glucose consumption. Acetic acid and butyric acid were the main by-products from the glucose degradation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.3
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• pp.558-564
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• 2012

We fabricated Ga doped ZnO (GZO) thin films on the glass substrate (Eagle 2000) with various of Ga doping concentration and annealing temperatures using sol-gel method, electrical and optical properties were investigated. When the GZO thin films doped with 1 mol% of Ga and annealed at $600^{\circ}C$, the excellent (002) orientation was observed. In the results of Hall measurement, carrier concentration decreased and resistivity increased due to segregation effect with increasing of the Ga doping concentration. The largest carrier concentration and lowest resistivity were $9.13{\times}10^{18}cm^{-3}$ and $0.87{\Omega}cm$, respectively, in the GZO thin films doped with 1 mol% Ga and annealed at $600^{\circ}C$. All films is higher than 80 % in the visible light region. Energy band gap narrowing due to Burstein-Moss effect was observed with increasing of Ga doping concentration from 1 to 4 mol%.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.4
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• pp.21-27
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• 2024

In this study, the corrosion density of tendon was evaluated with changing chloride and hydroxide ions. To simulate an accelerated corrosive environment, wet sand was used instead of concrete, and the tests were conducted considering three levels of chloride concentration (0.0, 0.125, and 0.250mol/l ) and three [Cl^-]/[OH^-] ratios (0.3, 0.6, and 0.9). The corrosion density was measured to 5.13 µA/cm² at 0.0mol/l and increased with the chloride concentration. Additionally, no significant differences were observed over 0.125mol/l of chloride concentration. When [OH^-] increased with a given chloride concentration (0.125mol/l), the corrosion density decreased linearly, showing effective control of corrosion density even at high chloride concentrations. Notably, the measured corrosion amounts were lower than those under of 0.0mol/l condition. Furthermore corrosion density and influencing parameters were normalized with the maximum and minimum results, and the relation between them was analyzed.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.4
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• pp.226-234
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• 2002

A sediment exposure experiment was conducted to investigate the influence of acid volatile sulfides (AVS) and simultaneously extracted metals (SEM) in sediments on the bioavailability and toxicity of Cd, Ni and Zn to a marine polychaetes Neanthes arenaceodentata. The test animals were exposed to contaminated sediments spiked by metal mixtures of Cd, Ni, Zn (0.5～15 $\mu$mol/g of total SEM) in low (～1 $\mu$mol/g), medium (～5 $\mu$mol/g) and high AVS series (～10 $\mu$mol/g) to determine bioaccumulation, mortality and individual growth rate in each treatment after 20 days. Cd and Zn bioaccumulation in test animals increased with increasing of overlying water (OW) concentration controlled by AVS. In contrast, Ni bioaccumulation increased with increase of SEM concentration. Mortalities and growth inhibitions of N. arenaceodentata observed in only treatments with ［SEM-AVS］>0, due to a high level of OW-Zn. With regard to the mortality, the 20-d LC5O value fur OW-Zn was 9.3(8.0$\pm$11.0) $\mu$M. The LOEC (Lowest Observed Effect Concentration) for Tissue-Zn was 7.8 $\mu$mol/g and the NOEC (No Observed Effect Concentration) was 6.2 $\mu$mol/g. Regarding the inhibition of individual growth rate, the LOEC fer Tissue-Zn was 5.9 $\mu$mol/g, and NOEC was 5.1 $\mu$mol/g. In this study, the toxicity of dissolved metals, especially for Zn, was overemphasized due to the reduced distribution coefficients (K$\_$d/s) of metals in the experimental sediments.