• Applied Biological Chemistry
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• v.28 no.2
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• pp.98-105
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• 1985

In the sheep and cattle's rumen, facultative anaerobic cellulolytic bacteria were isolated by using Hungate's roll tube technique. In the 21 isolated species, one was screened by its strong cellulolytic activity and identified as Cellulomonas fimi C-14 by investigate morphological, cultural, physiological characteristics and electron microgram. Optimum conditions of the cell growth and enzyme production were pH 6.5 an $30^{\circ}C$, Thiamine and biotin support a good growth of C. fimi C-14. In the enzyme activities, Crystalline cellulose hydrolyzing activity, CMCase activity and ${\beta}-glucosidase$ activity were 20.6, 226.6 and 0.56$(unit{\times}10^3/ml)$ at pH 6.0, $40^{\circ}C$. By addition of fungal cellulase, enzyme activity was increased. Simultaneous Saccharification Fermentation is better than two step fermentation in ethanol yield with Saccharomyces cerevisiae DY2.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.3
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• pp.109-114
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• 2016

Monodispersed $ZnGa_2O_4$ microspheres were synthesized by a facile two-step process consisting of a solvothermal method and calcination process. The prepared monodispersed $ZnGa_2O_4$ microspheres were aggregated into 3D microstructures by self-assembly with a large number of small $ZnGa_2O_4$ particles generated in nucleation. This nucleation and self-assembly making hierarchical microstructures were depended on the concentration of PEG (polyethylene glycol) due to CAC (critical aggregation concentration) theory. And also we controlled the amount of zinc acetate to make pure $ZnGa_2O_4$ phase. Additionally, to fix the optimized calcination condition, sample was characterized by TG-DTA to prove the thermal property in the calcination process and by FT-IR to identify the changes of functional group bonding between each element of the $ZnGa_2O_4$ precursor and oxide calcined at $900^{\circ}C$ for 1 h.

• Journal of the Korean Ceramic Society
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• v.38 no.12
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• pp.1137-1143
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• 2001

In this study, glass-ceramics containing cordierite(2MgO$.$2Al$_2$O$_3$5SiO$_2$) as a major crystalline phase was prepared from MAS (MgO-Al$_2$O$_3$-SiO$_2$) glass system for the application to reflector. Glasses prepared with addition of TiO$_2$as a nucleating agent were crystallized by two-step heat treatment of nucleation and crystal growth. Then nucleation and crystal growth behavior were investigated and the influence of heat treatment schedule on the nature of crystal phases and the diffuse reflectance spectrum was investigated. As a result, cordierite and rutile were precipitated as a major crystalline phases for the glass-ceramics with the nucleation at 750$^{\circ}C$ for 3 hours and then crystallization at 1100$^{\circ}C$ for 5 hours, and this glass-ceramics showed the reflectance over 90% in 570∼2500nm specturm region.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.59.2-59.2
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• 2020

Disks around protostars are the birthplace of planets. The first step toward planet formation is grain growth from ㎛-sized grains to mm/cm-sized grains in a disk, particularly in dense regions. In order to study whether grains grow and segregate at the protostellar stage, we investigate the ALMA Band 3 (3.1 mm) and 7 (0.87 mm) dust continuum observations of the protostellar disk WL 17 in ρ Ophiuchus L1688 cloud. As reported in a previous study, the Band 3 image shows substructures: a narrow ring and a large central hole. On the other hand, the Band 7 image shows different substructures: a non-axisymmetric ring and an off-center hole. The two-band observations provide a mean spectral index of 2.3, which suggests the presence of mm/cm-sized large grains. Its non-axisymmetric distribution may imply dust segregation between small and large grains. We perform radiative transfer modeling to examine the size and spatial distributions of dust grains in the WL 17 disk. The best-fit model suggests that large grains (>1 cm) exist in the disk, settling down toward the midplane, whereas small grains (~10 ㎛) well mixed with gas are distributed off-center and non-axisymmetrically in a thick layer. The low spectral index and the modeling results suggest that grains rapidly grow at the protostellar stage and that grains differently distribute depending on sizes, resulting in substructures varying with observed wavelengths. To understand the differential grain distributions and substructures, we discuss the effects of the protoplanet(s) expected inside the large hole and the possibility of gravitational instability.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.19 no.4
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• pp.414-434
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• 1997

Though many genetic and epigenetic alterations have been identified in hamster oral carcinogenesis model, there is no information about the possible role of transforming growth factor related with oral cancer. The purpose of this paper was to find the expression patterns of transforming growth factor alpha and beta during the stages of complete oral carcinogenesis model in hamster. 0.5% 9, 10-dimethyl-1, 2-benzanthracene(DMBA) in mineral oil was topically applied to the buccal pouch of 75 hamster three times a week during the experimental periods. The experimental animals were subdivided into two groups of control and experiment. Only the mineral oil was applied to the control group. 0.5% DMBA in mineral oil was applied to the experimental groups of 6, 8, 10, 12, 14, 16, 18 and 20 weeks. The expression of the $TGF-{\alpha}$ and $TGF-{\beta}$ protein were evaluated by the distribution and intensity of positive cells during the carcinogenesis using the immunohistochemical study. The following results were obtained ; 1. The buccal pouch epithelium of hamster was histologically changed to the dysplasia at 6, 8, 10 weeks, carcinoma in situ at 12 weeks, and squamous cell carcinoma at 14 weeks. 2. The expression of the $TGF-{\alpha}$ was restricted to the parabasal and basal layers of the normal and dysplastic mucosa, but those positive cells were extended to the spinous layers of the epithelium in the carcinoma. 3. The degree of $TGF-{\alpha}$ expression was markedly decreased in the carcinoma at 16, 18, 20. The strong positive staining in the center of cancer islands and weak positive staining in periphery of tumor were seen at the stage of squamous cell carcinoma. 4. The positive index of the $TGF-{\alpha}$ had a tendency to increase with DMBA- applied time. There was a statistically significant difference between 12, 18, 20 experimental group and control group (p<0.05). 5. The expression of the $TGF-{\beta}$ was shown at the cytoplasm of all control and experimental groups, and the parabasal and basal layers of the normal and dyslastic mucosa, but it was shown at the basal layers of the epithelium in the carcinoma. 6. $TGF-{\beta}$ was expressed diffusely at 16, 18, 20 experimental group. The strong positive staining in the center of cancer islands and positive staining in periphery of tumor were seen at the stage of squamous cell carcinoma. From the above findings, the expression of $TGF-{\alpha}$ and ${\beta}$ in oral carcinogenesis model seems to have two formal stages, the first being an overexpression step as reaction to uncontrolled growth and the second being one in which external protein accumulate in the surrounding stroma and intracytoplasm. Overexpression of $TGF-{\alpha}$ and ${\beta}$ may have important cooperative roles for the promotion of cancer and factor of prognosis.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.235-235
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• 2003

The development of a buffer layer is an important issue for the second -generation wire, YBCO coated metal wire. The buffer layer demands not only on the prohibition of the reaction between YBCO and metal substrate, but also the proper lattice match and conductivity for high critical current density (Jc) of YBCO superconductor, In order to satisfy these demands, we suggested CaRuO3 as a useful candidate having that the lattice mismatches with Ni (200) and with YBCO are 8.2% and 8.0%, respectively. The CaRuO3 thin films were deposited on Ni substrates using various methods, such as e-beam evaporation and DC and RF magnetron sputtering. These films were investigated using SEM, XRD, pole-figure and AES. In e-beam evaporation, the deposition temperature of CaRuO3 was the most important since both hi-axial texturing and NiO formation between Ni and CaRuO3 depended on it. Also, the oxygen flow rate had i[n effect on the growth of CaRuO3 on Ni substrates. The optimal conditions of crystal growth and film uniformity were 400$^{\circ}C$, 50 ㎃ and 7 ㎸ when oxygen flow rate was 70∼100sccm In RF magnetron sputtering, CaRuO3 was deposited on Ni substrates with various conditions and annealing temperatures. As a result, the conductivity of CaRuO3 thin films was dependent on CaRuO3 layer thickness and fabrication temperature. We suggested the multi-step deposition, such as two-step deposition with different temperature, to prohibit the NiO formation and to control the hi-axial texture.

• Journal of Korea Port Economic Association
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• v.29 no.2
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• pp.39-61
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• 2013

China, a leader of regional economies in North-East Asia, helps to integrate a single shipping market and affects diversely main ports in the region through affecting the flows of container transshipment, strategies of shipping companies for port calling and shipping networks. This study examines competition and cooperation among the hub ports in the region through studying examples of the three Chinese hub ports -Hong Kong, Shanghai, and Tianjin- and concludes some implications of status change of hub ports in the region after scrutinising development process of the Chinese main hub ports and the historic interaction of port development among these ports. The characteristics of growth pattern of three ports are as follows. The port of Hong Kong constructs step by step the container facilities in accordance with demand growth and prefers stabilisation of operation and management through scale enlargement of port facilities. Even though demand grows continually, the port of Shanghai continued its defensive attitude towards facility expansion till the 1990s and has tried to get economies of scale in enlargement of port facilities. The port of Tianjin, similarly as the two other ports, expands serially its facilities and utilizes the capacity concentration and functional specialisation of facilities. The analysis of panel data and panel regression of three hub ports implicates that each port has its own specific demand and shows that the interaction of container handling among three ports was weak in 1980s and has become stricter and stronger since 1990.

• Survey Research
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• v.7 no.1
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• pp.55-84
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• 2006

This study has classified development stages (Embryonic-Growth-Maturity) of mobile telecommunication industry based on Industry Life Cycle theory. There are two steps to be analyzed in this study, In the first step, cluster was investigated through cluster analysis using mobile density to categorize development stages of mobile telecommunication industry. In the second step, we compared on indexes of market structure, market efficiency and market performance to find out characteristics of each stage of development. The results are as follows. First, HHI is higher at embryonic stage than at growth and maturity stages, Second, ARPU(Average Revenue Per User) and RPM(Revenue Per Minute) are getting higher as the stages move on. Third, EBITDA margins, an index of market performance, is decreasing along the three stages. Finally, this study presents a clue to define the stage of development of mobile telecommunication industry and build a proper strategy for the market change.

• Food Science of Animal Resources
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• v.22 no.1
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• pp.59-65
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• 2002

This study was carried out to evaluate the effect of whey protein concentrate-80%(WPC-80) and whey protein isolate(WPI) on the growth of B. bifidum Bb-11. Whey proteins($\alpha$-lactalbumin, $\beta$-lactoglobulin) were digested with trypsin, then their hydrolyzates were separated into three fractions (>10,000Da, 3,000∼10,000Da, <3,000Da) by two-step ultrafiltration process with Centriprep 10 and Centricon-30. These three fractions by molecular weight were evaluate growth-promoting effects for the B. bifidum Bb-11. The results obtained were summarized as follows; The growth rate of B. bifidum Bb-11 tended to increase by supplementation of WPC-80 to basal medium, but decreased by supplementation of WPI. Two whey proteins were hydrolyzed by trypsin at 40$\^{C}$ for 6 hrs, and three fractions were collected by UF treatment and concentrated by Centricon-30. Collected concentrations of protein of F-I and F-II and F-III from $\alpha$-lactalbumin were 11.53mg, 7.79mg, and 5.21 mg and those of protein from $\beta$-lactoglobulin were 4.13mg, 5.30mg, and 9.351mg, respectively. Three fractions of $\alpha$-lactalbumin hydrolyzates promoted the growth rate of B. dbifidum Bb-11. Growth promoting activities of hydrolyzates(F-I and F-II) with molecular weight below 10,000Da were stronger than that of hydrolyzate(F-III) above 10,000Da. However, there was no significant difference between the hydrolyzate F-I and F-II. Three fractions of $\beta$-lactoglobulin hydrolyzates improves the growth rate of B.bifidum Bb-ll. The growth of B.bifidum Bb-ll was decreased after 24 hr incubation by supplementation of either F-II or F-III fraction compared to basal Whey medium, but maintained the enhancement by supplementation of F-I.

• Journal of the Korean Magnetics Society
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• v.20 no.5
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• pp.191-195
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• 2010

We have investigated the effect of the removal of an initial oxide layer and the anodization time on the growth of the porous alumina layer. The porous alumina layer was fabricated by two-step anodization process with phosphoric acid. We have observed the changes in the uniformity of the pore structure by varying the removing time of the initial oxide layer after the first anodization with phosphoric acid and chromic acid, and noted that its uniformity improves with the removing time. We have also determined the thickness of the alumina layer after the final anodization process and found that the thickness increases linearly with the anodization time. Under 150 V of anodization voltage with phosphoric acid, the growth rate of the porous alumina layer is determined to be 22.5 nm/min.