• Journal of Life Science
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• v.23 no.12
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• pp.1454-1459
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• 2013

This study investigated the effects that water temperature and the administration of estradiol-17${\beta}$ (E2) had on the sex ratio and growth of the Japanese eel, Anguilla japonica. Glass eels (total length${\fallingdotseq}$6.5 cm) were differentiated into an E2 group and an E2-free group and then they were reared for about four months at three water temperature levels of $20^{\circ}C$, $24^{\circ}C$, and $28^{\circ}C$. The results showed that the young eels survived normally at the rearing water temperature of ${\geq}24^{\circ}C$, and grew to a mean size of 20 cm (total length). In the E2-free group, temperature was not found to increase the sex ratio (feminizing rates); however, the sex ratio of the E2-administrated group was found to be a little higher at a high temperature ($28^{\circ}C$). The growth of the E2 group was lower than the growth of the E2-free group at $24^{\circ}C$ and the E2 concentration levels in the plasma at $24^{\circ}C$ were found to be significant after the end of the E2 administration period (178 days). Therefore, we thought that long-term administration of E2 must be considered to be the reason for growth decline in spite of the prominent sex ratio effect. Our results indicate that temperature was not related to an increase in the feminizing rate (sex ratio) in the Japanese eel, Anguilla japonica, and other environmental factors (rearing density, salinity, etc.) that have the possibility of inducing ovarian differentiation must be investigated.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.2
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• pp.161-174
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• 2011

The purpose of this study was to evaluate the effect of ethanol addition on efficacy of two-step total-etch adhesive under over-wet condition by measurement of remaining volatile part (RVP), microtensile bond strength (${\mu}TBS$), and degree of conversion (DC). Two-step total-etch adhesive, Optibond Solo Plus (Kerr, Orange, USA), was used. Experimental groups were divided into 8 groups: Group 1 (only 10 ${\mu}l$ adhesive), Group 2 (mixture of 3 ${\mu}l$ distilled water and 10 ${\mu}l$ adhesive), From Group 3 to Group 8 (mixture of 3 ${\mu}l$ distilled water, 10 ${\mu}l$ adhesive, and ethanol added in 1 ${\mu}l$ increment from 1 ${\mu}l$ to 6 ${\mu}l$). The mixtures were placed on slide glass and evaporated for 10 s, 30 s, and 60 s by air-drying. The weight of RVP was measured by precision weight. Same procedures were performed for ${\mu}TBS$ test and measurement of DC. The condition of mixed solution was observed under light microscope. For RVP weight, the weights of experimental groups except for group 1 decreased with the increase of air-drying time (p<0.05). The DC increased with the increase of air-drying time in only group 5 and 6 (p<0.05). The ${\mu}TBS$ increased with the increase of air-drying time in group only 5, 6, and 7 (p<0.05). The phase separation was examined and water blisters were diminished with the increase of air-drying time in group 5, 6, 7, and 8. Within the limits of this study, ethanol additionally applied to adhesive decreased RVP and increased DC and ${\mu}TBS$ under over-wet condition. It was shown that the addition of ethanol to two-step total-etch adhesive under over-wet condition would remove water and increase the efficacy of adhesive.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.468-476
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• 2021

This study examined the effects of a hydrothermal pretreatment (HP) on the nutritional values and in vitro fermentation characteristics of tall fescue and corn silage. This study was conducted through a factorial design of 2 (control or HP) × 2 (hay; tall fescue or silage; corn). For the HP, forage was placed into a glass bottle with 20% w/v of water, and the glass bottle was sealed and heated to reach a temperature of 121℃ (0.12 MPa). The solid residue and liquid were collected and oven-dried at 65℃ for three days. The dried materials were tested for in vitro fermentation at 39℃ for 24 and 48 h. The content of ADF increased significantly regardless of the forage type. After in vitro incubation for 24 h, the total VFA content was significantly lower after HP, regardless of the forage type (p ≤ 0.05), and the propionate concentration was increased in corn silage with HP (p ≤ 0.05). After 48 hours of in vitro incubation, the propionate content increased significantly (p ≤ 0.03) in corn silage with HP (p ≤ 0.05), but the butyrate content decreased significantly (p ≤ 0.05). There was no change in the in vitro dry matter and neutral detergent fiber digestibility by HP regardless of the forage type. Therefore, the use of hydrothermally pretreated corn silage could be advantageous for the supply of energy for ruminants.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.204-205
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• 2011

In thin film silicon solar cells, p-i-n structure is adopted instead of p/n junction structure as in wafer-based Si solar cells. PECVD is a most widely used thin film deposition process for a-Si:H or ${\mu}c$-Si:H solar cells. For best performance of thin film silicon solar cell, the dopant profiles at p/i and i/n interfaces need to be as sharp as possible. The sharpness of dopant profiles can easily achieved when using multi-chamber PECVD equipment, in which each layer is deposited in separate chamber. However, in a single-chamber PECVD system, doped and intrinsic layers are deposited in one plasma chamber, which inevitably impedes sharp dopant profiles at the interfaces due to the contamination from previous deposition process. The cross-contamination between layers is a serious drawback of a single-chamber PECVD system in spite of the advantage of lower initial investment cost for the equipment. In order to resolve the cross-contamination problem in single-chamber PECVD systems, flushing method of the chamber with NH3 gas or water vapor after doped layer deposition process has been used. In this study, a new plasma process to solve the cross-contamination problem in a single-chamber PECVD system was suggested. A single-chamber VHF-PECVD system was used for superstrate type p-i-n a-Si:H solar cell manufacturing on Asahi-type U FTO glass. A 80 MHz and 20 watts of pulsed RF power was applied to the parallel plate RF cathode at the frequency of 10 kHz and 80% duty ratio. A mixture gas of Ar, H2 and SiH4 was used for i-layer deposition and the deposition pressure was 0.4 Torr. For p and n layer deposition, B2H6 and PH3 was used as doping gas, respectively. The deposition temperature was $250^{\circ}C$ and the total p-i-n layer thickness was about $3500{\AA}$. In order to remove the deposited B inside of the vacuum chamber during p-layer deposition, a high pulsed RF power of about 80 W was applied right after p-layer deposition without SiH4 gas, which is followed by i-layer and n-layer deposition. Finally, Ag was deposited as top electrode. The best initial solar cell efficiency of 9.5 % for test cell area of 0.2 $cm^2$ could be achieved by applying the in-situ plasma cleaning method. The dependence on RF power and treatment time was investigated along with the SIMS analysis of the p-i interface for boron profiles.

• The Journal of Engineering Geology
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• v.14 no.3 s.40
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• pp.273-285
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• 2004

The mechanical properties of the Cretaceous tuff distributed in the Goheung area were measured in the laboratory. Tuff (Goehung tuff and Palyeongsan welded tuff) in the study area is classified into vitric tuff with regard to its composition. The specific gravity, the dry density, the water content, the porosity and absorption ratio in tuffs of the study area are 2.51, $2.52(g/cm^2)$, 0.12($\%$), 4.51($\%$) and 1.91($\%$) in means, respectively. In the tuffs, dry densities are in inverse Proportion to Porosities, and absorption ratios are highly proportional with Porosities. The uniaxial compressive strengths(UCS) in the tuffs ranges from 80.4 to 208(MPa) and the average of the strength is 141.1(MPa). According to the engineering classification of intact rock (Deere & Miller, 1966), the tuffs are assigned to the high strength rocks. The point load strength index ($Is_a$) in axial test is 4.2(MPa) on the average, and the point load strength index ($Is_d$) in diametral test is 2.2(MPa) in mean, and the point load strength anisotrophic index($Ia_{(50)}$) by the ratio of $Is_a$ to $Is_d$ is 1.93. There is close linear correlation between the uniaxial compressive strength and point load strength index, and the equation representing the correlation is postulated as follows : UCS = 22 $Is_{(50)}$ +49 (MPa) (r=0.95). It is considered that this equation is a useful tool to estimate UCS for tuff in Goheung area.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.8
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• pp.1128-1133
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• 2002

The whole plant of crop maize was chopped and ensiled in airtight 1-L capacity glass jars to determine the influence of residual sugar on anaerobic yeast growth and on the fermentation of lactic acid by L. buchneri in whole crop maize silage. There were a total of six treatments used in this experiment as follow: added 25 g de-mineralised water per kg chopped maize serving as control (con), 37.5 g glucose solution containing 12.5 g glucose ($g_1$), 75 g glucose solution containing 25 g glucose ($g_2$), 25 g L. buchneri suspension intended for $10^6$ cfu $g^{-1}$ (L.b.), $g_1+L.b.$ and $g_2+L.b.$ All silos were stored in the dark at $20^{\circ}C$ until end of experiment. Jars were opened on duplicates at day 2, 7, 14, 28, 56 or triplicates at day 91 after ensiling for measuring the pH, microbiological enumeration and fermentative products. Results indicated that acidification rates for all silages were very fast, no difference occurred among treatments before day 28. After day 28 the pH values for silages inoculated by L. buchneri. with or without sugar tended to increase especially for treated only with L. buchneri, resulting in higher (p<0.01) finial pH than uninoculated silages. Compared with control silage, the added sugar significantly (p<0.01) increased dry matter (DM) loss, L. buchneri enhanced (p<0.01) DM loss further at different sugar existence. Silages inoculated by L. buchneri only or in combination with sugar addition contained less (p<0.01) lactic acid than the correspondent silages without inoculation with L. buchneri. In comparison with control, ethanol production is about 3 or 6 fold higher due to addition 12.5 or 25 g glucose per kg chopped maize at ensiling. The added sugar resulted in less acetic acid concentration (p<0.01) than control, but inoculation with L. buchneri increased (p<0.01) acetic acid than correspondent uninoculated silages at different sugar levels. No butyric acid and propionic acid were found in uninoculted silages, silages inoculated with L. buchneri. produced more propionic acid, 1-propanol and butyric acid. Lactobacilli counts were not influenced by added sugar, but increased (p<0.01) with inoculation of L. buchneri. The added sugar increased significantly (p<0.01) the yeast count, whereas L. buchneri showed the contrary effect. No differences were found in the aerobic stability among all treatments. In conclusions, 1) the added sugars encourage the growth of yeast and yeasts convert extra sugar into ethanol in maize silages. 2) The added sugars and L. buchneri do not influence the aerobic stability of silages stored in anaerobic silos.

• Journal of agriculture & life science
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• v.46 no.3
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• pp.119-127
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• 2012

For the promotion of the evaporative cooling efficiency of hot air in greenhouse in summer, a fog sprayer consisted of a high volume spraying two-fluid nozzle with turbo fan and a blowing fan was set up at 2.2 m height from bottom of small glass greenhouse and tested to estimate the possibility of the greenhouse cooling. The mean droplet size and the volume sprayed by one of fog sprayer were $29{\mu}m$ and $160m{\ell}/min$. All the droplets sprayed and blown by the fog sprayer were evaporated within 2 m radius. The result from the cooling test that two sprayers set up in glass greenhouse of plane area $228m^2$ was represented lower cooling effect that the temperature and relative humidity of inside air of greenhouse were $28.8^{\circ}C$ and 87.5% when those of outside air of greenhouse were $30.2^{\circ}C$ and 81.2%. Through investigation of literatures and results of the cooling test, it was estimated that the water spraying rate of evaporative cooling of single span greenhouse with 50% light curtain and with air change rate of 1 volume/min was $10m{\ell}/min/m^2$ so that the inside air temperature may cool down $2{\sim}3^{\circ}C$ on the basis of $35^{\circ}C$ atmospheric temperature in summer of south korean area.

• Journal of the Korean Society of Radiology
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• v.14 no.7
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• pp.981-989
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• 2020

In this study, a self-made customized phantom was used to quantitatively measure the change in CT number and noise according to the change of pitch. In order to acquire an image using the phantom, the inside of the phantom was filled with sterile distilled water. Inside the glass tube, a solution obtained by diluting the ratio of normal saline and contrast medium to 100%(NS), 400:1, 200:1, 100:1, 50:1, respectively, was placed and imaged. At this time, the pitch was divided into steps of 0, 0.35, 0.7, 1.05, and 1.4 for each dilution ratio of the solution and imaged, respectively. One-way ANOVA analysis were performed to verify whether the mean of the CT number and noise values measured in all ROIs by dilution ratio showed a significant difference according to the change in pitch. As a result of the experiment, there was no statistically significant difference in the change of the CT number according to the change in the pitch for each dilution ratio, but the noise value tended to increase with the increase of the pitch, and showed a statistically significant difference. In the spiral image acquisition of CT, noise can be changed to a significant level depending on the pitch. Therefore, it will be necessary to set the quality evaluation items and criteria for CT images using the spiral image acquisition method.

• The Korean Journal of Physiology
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• v.14 no.1
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• pp.1-5
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• 1980

This study was under taken to investigate the influences of predictable or unpredictable stress upon gastric ulceration, and the hippocampectomy upon the ulceration order the stressful conditions. Sixty male albino rats(Sprague-Dawley strain) were divided equally into 3 groups: One was the hippocampal group(N=20) which received hippocampal ablation by suction, another was the cortical control group(N =20) which received partial cortical ablation over the hippocampus, and a third was the normal control group(N=20). Each group was further divided into two subgroups: One was the predicted subgroup(N=10) in which animals could predict the imminent stressful stimuli by hearing a sound(1,000 Hz, 2 sec in duration) 3 sec before the onset of the stress, and the other was the unpredicted subgroup(N=10). After starvation for 24 hours, but water ad libitum, each rat received the electric stimulation(3 mA, 60 Hz, 2 sec in duration, and once per minute in average) for 6 hours via a pair of electrodes attached on the tale. The electric stimulation served as the stress causing the gastric ulcer. Five hours after completion of stimulation, the stomach filled with the physiological saline was removed under deep anesthesia and spread out on a small glass plate. The numbers of the ulcer in each stomach were counted and the shape was examined under the dissecting microscope. Results obtained were as follows: 1. The mean numbers of the ulcer of the predicted subgroups were significantly larger than those of the unpredicted subgroups in the normal control and the cortical control groups, but there was no difference between the values of the two subgroups in the hippocampal group. 2. The mean numbers of the ulcer of the predicted subgroups in the normal control and the cortical control groups were larger(but not significant) than that in the hippocampal group. It is inferred from the above results that the prediction of the stress strengthens the effect of the stress on the gastric ulceration, and the hippocampus facilitates the effect of the prediction of the stress.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.2
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• pp.226-241
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• 2000

Recently a new generation of crown and bridge veneering resins containing submicron glass fillers was introduced. These ultrasmall particle hybrid composite materials distinguish themselves, compared with conventional microfill crown and bridge resins, through improved mechanical properties. It is claimed that these composites are suitable for metal free crowns and even bridges using fiber reinforcement. The purpose of this study was to evaluate the effect of thermal cycling on the tensile strength of the following veneering composites: Artglass(Heraeus Kulzer Co., Wehrheim, Germany), Estonia(Kuraray Co.. Japan), Sculpture(Jeneric Pentron Co., Wallingford, U.S.A.), and Targis(Ivoclar Co., Schaan Liechenstein). According to manufacturer's instructions, rectangular tensile test specimens measuring $1.5{\times}2.0{\times}4.5mm$ were made using a teflon mold. Whole specimens were divided into two groups. One group was dried in a desiccator at $25^{\circ}C$ for 10 days, and another group was subjected to thermal cycling($10,000{\times}$) in water($5/55^{\circ}C$). All test specimens were placed in a universal testing machine and loaded until fracture with a crosshead speed of 0.5mm/min. Weibull analysis and Tukey's test were used to analyze the data. The fracture surfaces of specimens were observed in SEM and the aliphatic C=C absorbance peak of Estenia and Targis resin was analyzed using Fourier transform infrared(FTIR) spectroscopy. Within the limitations imposed in this study, the following conclusions can be drawn: 1. Both in drying condition and thermal cycling condition, the highest tensile strength was observed in Estenia testing group(p<0.05). 2. The strength data were at to single-mode Weibull distribution, and the Weibull modulus of all veneering composite resin specimens increased after thermal cycling treatment. 3. After thermal cycling test, the highest tensile strength was observed in the Estenia group, and the lowest value was observed in the Targis group. The tensile strength values showed the significant differences between each group(p<0.05) 4. The aliphatic C=C absorbance peak of Estonia and Targis resin was decreased after light curing, and there was no distinct change after thermal cycling.