• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.5
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• pp.643-650
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• 1996

A long term feeding trial was conducted to study the effects of different dietary vitamin C levels on growth and its tissue distributions in juvenile Korean rockfish, Sebastes schlegeli. Prior to the start of feeding trial, fish were fed the basal diet supplementing no L-ascorbic acid for four weeks to minimize their body reserves of vitamin C. Then fish were divided into six groups with triplicates and given one of the laboratory semipurified diets supplementing either 0, 25, 50, 75, 150, or 1500 mg L-ascovbic acid (AA)/kg diet $(C_0,\;C_{25},\;C_{50},\;C_{75},\;C_{150},\;&\;C_{1500})$. Fish fed the $C_0$ diet had lower percent weight gain, feed conversion ratio, specific growth rate, and protein efficiency ratio than did fish fed the other diets (P<0.05). After 28 weeks of feeding trial, tissue AA concentrations of fish fed $C_0$ diet were lower than those of fish fed $C_{1500}$ diet (P<0.05). A large amount of total tissue Ah may be reserved in muscle, but the unit AA concentration seemed to be higher in brain than did the other tissues. The growth performances of fish fed $C_{25}$ diet were not different compared to those of fish fed $C_{50}-C_{1500}$ diets (P>0.05), and diet analysis of vitamin C showed that the $C_{25}$ diet had 65 mg AA/kg diet. Therefore, the present long-term study may suggest that the dietary vitamin C requirement is approximately 65 mg AA/kg diet in juvenile Korean rockfish.

• The Korean Journal of Mycology
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• v.26 no.1 s.84
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• pp.1-7
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• 1998

In order to find relationship within and between entomopathogenic species, analysis of protein band pattern in mycelia of 25 isolates was conducted by UPGMA. The results allowed differentiation of three groups on 85% similarity coefficient. Similarity coefficient within C. militaris was $0.787{\sim}1.000$, C. kyushuensis was 0.958-1.000 and C. pruinosa was 0.993-1.000. C210 and C298 isolates which had somewhat immersed perithecia, comparable to other C. militaris isolates, had 91% similarity. C108, C225-1 and C228 isolates pathogenic on Lepidopterous larvae had 89% similarity. Closely related species to C. militaris were C. kyushuensis and C. pruinosa. And similarity between C. pruinosa and C. kyushuensis was 88%. Similarity between C. bifusispora formed conidia on media and Paecilomyces tenuipes was 89%. C. scarabaeicola pathogenic specifically on adult Scarabaeidae had 82% similarity with above two species. C118 identified as C. militaris showed different protein banding patterns.

• Journal of Bio-Environment Control
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• v.6 no.2
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• pp.110-116
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• 1997

This experiment was conducted to investigate the effects of root zone warming on fruit yield of oriental melon (Cucumis melo L. var. Makuwa) in winter season. Root zone was warmed by hot water flowing through pipe set at 35cm depth from the ridge. Treatments of minimum soil temperature at 20cm depth were 17, 21, $25^{\circ}C$ and non-warming from Jan. 18 to Apr. 18. The results are summarized as follows. 1. The blooming of female flower was faster 1 days in 17$^{\circ}C$ plot, 6 days in 21$^{\circ}C$ plot, and 7 days in $25^{\circ}C$ plot than in control plot and the days from blooming to harvesting were shorter 5 days in 17$^{\circ}C$ plot, 11 days in 21$^{\circ}C$ plot, and 12 days in $25^{\circ}C$ plot than in control plot. 2. Mean fruit weight was the highest in 21$^{\circ}C$ plot, followed $25^{\circ}C$, 17$^{\circ}C$ and control plots, respectively, and flesh thickness was the highest in $25^{\circ}C$ plot, followed by 21, 17$^{\circ}C$ and control plots, respectively. 3. Early and middle-phase yield was the highest in $25^{\circ}C$ plot, followed by 21$^{\circ}C$, 17$^{\circ}C$ and control plots but late yield was the highest in 17$^{\circ}C$ plot, followed by control, 21, and $25^{\circ}C$ plots. Total yield per 10a was higher 33% in 17$^{\circ}C$ plot, 49% in 21$^{\circ}C$ plot, and 37a in $25^{\circ}C$ plots than in control plot, harvested 1, 490kg per 10a. 4. Total yield was highest in 21$^{\circ}C$ plot, followed by $25^{\circ}C$, 17$^{\circ}C$, and control plots. Malformed and fermented fruit rates were the highest in control, followed by 17, 25, and 21$^{\circ}C$ plots and marketable fruit rate was 21, 25, 17$^{\circ}C$, and control plot in order.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.39-42
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• 1999

Nitrogen-doped SiC(3C) (N-SiC(3C)) epliayers were grown on Si(111) substrate at $1250^{\circ}C$ using chemical vapor deposition (CVD) technique by pyrolyzing tetramethylsilane(TMS) in $H_{2}$ carrier gas. SiC(3C) layer was doped using $NH_{3}$ during the CVD growth to be n-type conduction. Physical properties of N-SiC(3C) were investigated by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) patterns, Raman spectroscopy, cross-sectional transmission electron microscopy (XTEM), Hall measurement, and current-voltage(I-V) characteristcs of the N-SiC(3C)/Si(p) diode. N-SiC(3C) layers exhibited n-type conductivity. The n-type doping of SiC(3C) could be controlled by nitrogen dopant using $NH_{3}$ at low temperature.

• The Korean Journal of Mycology
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• v.21 no.3
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• pp.224-229
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• 1993

The optimum temperature for germination of conidia and germ tube elongation were between $20\;and\;30^{\circ}C$ in C. dematium and C. gloeosporioides. Appressoria were fairly formed well at $20^{\circ}C$ despite the delay of conidial germination. At $30^{\circ}C$, both the germination and germ tube elongation are favored, but appressoria were poorly detected to be formed. In C. acutatum, the optimum temperature for germination of conidia was from $20\;to\;30^{\circ}C$, but at $25^{\circ}C$, germ tube elongation are accelerated. The conidia become septate and one or both doughter cells become conidiogenous instead of producing germ tubes and a secondary conidia produced, resulting in an arborescent type of connected conidia. Appressoria are infrequently formed by germinating conida. At $20\;to\;25^{\circ}C$ was the optimum for appressorium formation. But conidia that germinated at $30^{\circ}C$ seemed to lose the ability to form appressoria. The relation of temperature to germination of conidia and appressorium formation in Colletotrichum acutatum, C. dematium and C. gloeosporioides are discussed.

• Journal of Welding and Joining
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• v.14 no.4
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• pp.99-108
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• 1996

The microstructure and bond strength are examined on the SiC/SiC and SiC/mild steel joints brazed by the Ag-Ti based alloys with different Ti contents. In the SiC/SiC brazed joints, the thickness of the reaction layers at the bond interface and the Ti particles in the brazing alloy matrices increase with Ti contents. When Ti is added up to 9 at% in the brazing alloy. $Ti_3SiC_2$ phase in addition to TiC and $Ti_5Si_3$ phase is newly created at the bond interface and TiAg phase is produced from peritectic reaction in the brazing alloy matrix. In the SiC/mild steel joints brazed with different Ti contents, the microstructure at the bond interface and in the brazing alloy matrix near SiC varies similarly to the case of SiC/SiC brazed joints. But, in the brazing alloy matrix near the mild steel, Fe-Ti intermetallic compounds are produced and increased with Ti contents. The bond strengths of the SiC/SiC and SiC/mild steel brazed joints are independent on Ti contents in the brazing alloy. There are no large differences of the bond strength between SiC/SiC and SiC/mild steel brazed joints. In the SiC/mild steel brazed joints, Fe dissolved from the mild steel does not affect on the bond strength of the joints. Thermal contraction of the mild steel has nearly no effects on the bond strength due to the wide brazing gap of specimens used in the four-point bend test. The brazed joints has the average bond strength of about 200 MPa independently on Ti contents, Fe dissolution and joint type. Fracture in four-point bend test initiates at the interface between SiC and TiC reaction layer and propagates through SiC bulk. The adhesive strength between SiC and TiC reaction layer seems to mainly control the bond strength of the brazed joints.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.166-171
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• 2007

The characterization of monolithic SiC and SiCf/SiC composite materials fabricated by NITE and RS processes was investigated in conjunction with the detailed analysis of their microstructure and density. The NITE-SiC based materials were fabricated, using a SiC powder with average size of 30 nm. RS- SiCf/SiC composites were fabricated with a complex slurry of C and SiC powder. In the RS process, the average size of starting SiC particle and the blending ratio of C/SiC powder were $0.4\;{\mu}m$ and 0.4, respectively. The reinforcing materials for /SiC composites were BN-SiC coated Hi-Nicalon SiC fiber, unidirectional or plain woven Tyranno SA SiC fiber. The characterization of all materials was examined by the means of SEM, EDS and three point bending test. The density of NITE-SiCf/SiC composite increased with increasing the pressure holding time. RS-SiCf/SiC composites represented a great decrease of flexural strength at the temperature of $1000\;^{\circ}C.$

• Journal of Sensor Science and Technology
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• v.16 no.4
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• pp.319-323
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• 2007

This paper describes the mechanical characteristics of poly 3C-SiC thin films grown on Si wafers with thermal oxide. In this work, the poly 3C-SiC thin film was deposited by APCVD method using only Ar carrier gas and single precursor HMDS at $1100^{\circ}C$. The elastic modulus and hardness of poly 3C-SiC thin films were measured using nanoindentation. Also, the roughness of surface was investigated by AFM. The resulting values of elastic modulus E, hardness H and the roughness of the poly 3C-SiC film are 305 GPa, 26 GPa and 49.35 nm respectively. The mechanical properties of the grown poly 3C-SiC film are better than bulk Si wafers. Therefore, the poly 3C-SiC thin film is suitable for abrasion, high frequency and MEMS applications.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.1
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• pp.1-6
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• 1981

In this study, sesame oil was chosen as the experimental sample and analysed for its triglyceride composition by high-performance liquid chromatography(HPLC) in combination with gas liquid chromatography(GLC). The triglycerides were separated from sesame oil by liquid chromatographies on Bio-Beads SX-2 and on Sephadex LH-20, and fractionated into five groups on the basis of their partition numbers by reverse phase HPLC on a column packed with $\mu-Bondapak$ C18 using methanol-chloroform mix-ture as a solvent. Each of these collected fractions gave one to three peaks in the GLC chromatograms according to the acyl carbon number of the triglyceride, and fatty acid composition of the triglyceride was also analysed by GLC. From the results, it was found that the sesame oil consists with twenty one kinds of triglyceri-des, and the major triglycerides of sesame oil are those of $(2\;{\times}\;C18:1,\;C18:2\;;\;17.1\%),\;(C18:1,\;2{\times}C18:2\;;\;17.0\%),$ $(3\;{\times}\;C18:2\;;\;17.0\%),\;(3\;{\times}\;C18:1\;;\;10.9\%),$ $(3\;{\times}\;C18:2\;;\;9.6\%),\;(C16:0,\;C18:1,C18:2\;;\;7.9\%),$ $(C16:0,\;2\;{\times}\;C18:1\;;\;7.4\%),\;(C16:0,\;2\;{\times}\;C18:2\;;\;6.8\%),$ $(C18:0,\;C18:1,\;C18:2\;;\;3.1\%),\;(2\;{\times}\;C18:0,\;C18:2\;;\;1.5\%)$ $(C18:0,\;2\;{\times}\;C18:1\;;\;1.4\%),\;(C16:0,\;C18:0,\;C18:1\;;\;1.3\%),$ $(2\;{\times}\;C16:0,\;C18:1\;;\;1.2\%),\;and\;(C16:0,C18:0,\;C18:2\;;\;1.0\%)$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.6
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• pp.487-490
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• 2010

This paper describes the elecrtical and optical characteristics of $N_2$ doped porous 3C-SiC films. Polycrystalline 3C-SiC thin films are anodized by $HF+C_2H_5OH$ solution with UV-LED exposure. The growth of in-situ doped 3C-SiC thin films on p-type Si (100) wafers is carried out by using APCVD (atmospheric pressure chemical vapor deposition) with a single-precursor of HMDS (hexamethyildisilane: $Si_2(CH_3)_6)$. 0 ~ 40 sccm $N_2$ was used for doping. After the growth of doped 3C-SiC, porous 3C-SiC is formed by anodization with $7.1\;mA/cm^2$ current density for anodization time of 60 sec. The average pore diameter is about 30 nm, and etched area is increased with $N_2$ doping rate. These results are attributed to the decrease of crystallinity by $N_2$ doping. Mobility is dramatically decreased in porous 3C-SiC. The band gaps of polycrystalline 3C-SiC films and doped porous 3C-SiC are 2.5 eV and 2.7 eV, respectively.