• 한국표면공학회지
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• 제22권4호
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• pp.207-214
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• 1989

The surface morphology and the proferred orientation of the Pb-Sn alloy electrodeposite were investated by the change of electrolysis conditions in pulse current electroplating. The preferred orientation of Pb-phase in alloy deposits was changed in the sequence of (110)longrightarrow(100)or(100)+(111)longrightarrow(111) with increasing peak current density, while that of $\beta$-Sn phase changed from (321)+(301)to(301)+(111) mixed orientation. The surface morphology was closely related to the preferred orientation of alloy electrodeposits. The alloy deposits, which had (100)or(111) for pb-phase and (321)or(100)(301)for $\beta$-Sn sespectively, showed the surface structure of granular crystallites. The alloy deposits whih mixed orientations for both phases had microstructure of closely the closely stacked crysrallites, which was inclined to the surface.

• 한국표면공학회지
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• 제13권4호
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• pp.211-220
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• 1980

Internal stress of electrodeposited metals affect physical and mechanical characteristics of deposits. Internal stress of nickel deposits was reviewed intensively. Important outcomes are as follows. Substrate have an important effect on internal stress of electrodeposit. Origin of its internal stress could be explained mismatch of crystal lattice and coalescence of crystallites. When surface cleaning is not satisfying, instantaneous stress is low but the electrodeposited layer being thickened increasingly stress become to high and peeling phenomenon occurs. Effect of current density and temperature on internal stress is variable. Internal stress increases rapidly at pH 5 and above because of codepositing colloidal materials caused hydrolysis. Concentrations of nickel ion and $H_3BO_3$ ion affect little on internal stress and solution which contains impurities tend to increase stress. Especially impurities of $H_2O_2$ and iron ion have a great effect on internal stress. Additives are divided in two kind. One is increasing tensile stress another is increasing compressive stress. Concentrations of additives have a great effect on internal stress.

• 한국식품과학회지
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• 제16권3호
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• pp.363-367
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• 1984

Streptococcus lactis ATCC 11454 의 protoplast 생성 및 재생에 관하여 조사하였다. Protoplast의 생성은 용균효소로써 리소짐 단독처리 만으로 충분히 가능하였으며 균체의 배양은 20mM DL-트레오닌을 첨가한 배지를 사용하는 것이 좋았으며 생육시기와 리소짐 농도등이 중요한 영양인자였다. 배지조성의 최적화 및 protoplast를 배지에 접종하는 방법을 변형시킴으로써 약 20%정도의 재생효율을 얻을 수 있었다.

• 한국산학기술학회논문지
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• 제5권5호
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• pp.433-437
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• 2004

The MmSH is a process of injecting ABS to produce innovated physical properties compared to the conventional injection process. Physical properties such as thickness and adhesion strength of Ni plate electrolessly coated on a conventional and a MmSH injected ABS have been studied in the pH range 4~8. Thickness of the plate on the MmSH and the conventionally injected ABS appeared to be directly proportional to pH. The ABS processed by the conventional injection showed adhesion strength corresponded to ASTM 4B above pH 5. On the other hand, the ABS processed by the MmSH injection showed a superior adhesion strength corresponded to ASTM 5B above pH 6. It was calculated the shielding effectiveness of above 50 dB in all conditions.

• 한국표면공학회지
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• 제18권3호
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• pp.95-104
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• 1985

A study has been made of preferred orientation, crose sectional microstructure, surface morphology and mechanical properties of copper foils fabricated by electrodeposition on 304 stainless steel plate from copper sulfate baths for high speed plating. The preferred orientation of the copper foils changed from the [110] to the [111] to ture with decreasing bath temperature and increasing cathode current density. The foils with the [110] texture had the field oriented texture type structure and the surface of many asperities grooved approximately perpendicular to the subtrate. A specimen with the [111]+[311] texture had the lower strength than one with the [10] texture, if they were obtained under similar electrolysis conditions.

• 한국군사과학기술학회지
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• 제24권2호
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• pp.197-203
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• 2021

Mechanical structures of military equipment have been mainly applied with black oxide coating due to the limitation of surface treatment thickness. However, the mechanical structures applied by the black oxide coating treatment is constantly being corroded by calcium chloride and humidity. Since this can cause serious problems in the operation of equipment, a review to improve surface treatment and corrosion resistance is required. Therefore, in this study, surface treatment methods that can enhance corrosion resistance were selected and corrosion resistance performance was verified through experiments describing harsh field conditions. Thus, applying a proven surface treatment method to future military equipment will prevent corrosion.

• 대한족부족관절학회지
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• 제25권4호
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• pp.181-184
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• 2021

End-stage ankle arthritis is a debilitating condition that causes functional limitations and consequently a poor quality of life. Total ankle replacement arthroplasty is a good alternative to arthrodesis for preserving the ankle's range of motion. However, many complications can occur in patients with rheumatoid arthritis and with poor soft tissue and bone conditions. A 61-year-old female experienced spacer subluxation after surgery, which was not reduced by medial soft tissue release and spacer change. Buttress plating was found to be a good treatment option to prevent spacer subluxation and can be considered in patients with rheumatoid arthritis with bone erosion and soft tissue damage.

• 대한가정학회지
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• 제42권3호
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• pp.145-158
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• 2004

Experimental conditions for evaluating chitosan antibacterial activities were established. The chitosan antibacterial activities were measured against the Staphylococcus aureus and evaluated for their application to antibacterial textile finishing. The strain of Staphylococcus aureus used in this experiments was KCTC 1916. The chitosan antibacterial activities were estimated from the bacterial densities or ％reduction of bacteria in chitosan solutions and bacterial culture mixtures after incubation under specific conditions. Six parameters as follows were evaluated to optimize the experimental conditions for measuring antibacterial activities. The different combinations of mixtures according to the different ratios of chitosan solutions to the bacterial cultures showed different antibacterial activities. However, the chitosan antibacterial activities could be evaluated by comparing the data obtained from the same combinations of mixtures. The solvent influence on the chitosan solution antibacterial activities could be eliminated using control solution containing the same concentration of acetic acid. The initial pH of the chitosan -bacterial mixtures also affected the chitosan antibacterial activity; at a higher pH, higher activity in terms of ％reduction of bacteria was observed. In case of the bacterial solution without either the acetic acid or chitosan, the initial pH of the solution did not significantly affect bacterial growth. The ％ reduction of bacteria increased when contact times of bacteria with chitosan in the chitosan -bacterial mixture were expended upto 24 hours. However, the chitosan antibacterial activities could be successfully evaluated at contact time 0 where the chitosan-bacterial mixture was plated immediately after mixing and incubated to measure the bacterial number to 24 hours. Evaluating ％reduction of bacteria in the test mixtures after incubation were not changed when the inoculated bacterial concentrations were 2.3${\times}$10$\^$0/ml to 2.3${\times}$10$\^$6/ml. The optimal range of incubation time of the petri-Dish after plating the chitosan-bacterial mixture was 24 to 72 hours depending on the antibacterial activities of the test solutions.

• 한국수산과학회지
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• 제30권3호
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• pp.367-376
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• 1997

Vibrio vulnificus is a gram-negative, halophilic, oxidase-positive, lactose-positive, motile, rod shaped bacterium that has been associated with primary septicemia and wound infection. Elucidating the growth and survival of V. vulnificus in ecological conditions is of great importance to develop sanitary measure against this microorganism. Thus we simulated the ecological conditions and evaluated the effect. About $10^5\;CFU/ml$ of V. vulnificus was inoculated to fresh water, brackish water $(1\%\;NaCl)$, sea water $(3\%\;NaCl)$, and bottom deposit solution. The same concentration of V. vulnificus was also inoculated to distilled water, $1\%\;NaCl$ solution and $3\%\;NaCl$ solution as controls. These were stored at 4, 15 and $25^{\circ}C$, respectively and were used to assess the effects of temperature and salinity on the survival of V. vulnificus. In fresh water V. vulnificus could not survive regardless of storage temperature. In case of brackish water and sea water survival time of V. vulnificus was the longest at $25^{\circ}C$, and the number of V. vulnificus was decreased most rapidly at $4^{\circ}C$. V. vulnificus survived longer in brackish water than in any other conditions. In bottom deposit solution containing brackish water, the survival time of V. vulnificus was longer and the rate of decline was slower than that in brackish water. These results indicate that both biological and physicochemical factors such as temperature and salinity could affect survival of V. vulnificus. V. vulnificus, damaged in normal fresh water, did not grow on TCBS agar of selective plating medium but grew on BHI agar plate; However, V. vulnificus was recovered by addition of salt and nutrient materials.

• Radiation Oncology Journal
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• 제19권2호
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• pp.163-170
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• 2001

목적 : 방사선조사후 세포의 생존 분획은 세포집락 측정기법으로 확인하는 것이 표준이나 많은 비용과 시간이 소요되는 단점을 갖고 있다. 이에 생존 세포의 tetrazolium염의 자색 formazan 침전물로의 환원시키는 능력에 그 기반을 둔 MTT 기법을 사용하여 세포집락 측정기법을 대체하기 위한 기법으로서의 유용성과 그 실행상의 최적조건을 규명하고자 하였다. 방법 : PCI-1, SNU-1066, NCI-H630, RKO등의 세포주에 0, 2, 4, 6, 8, 10 Gy의 방사선을 조사한 후 세포집락 측정 기법과 MTT기법으로 세포 생존 분획을 조사하였다. 세포집락 측정기법은 $25\;cm^2$ 폴리스티렌 배양 플라스크에 방사선량에 따라 다른 수의 세포를 분주한 후 24시간 동안 배양 후 방사선을 조사하였고 이를 $10\~14$일 동안 배양 후 염색하여 생성된 세포집락의 수를 측정하였다. MTT기법은 침전물의 용해과정이 필요없는 Premix WST-1 시약을 이용하여 시행하였다. MTT기법은 각각의 세포주에서 세포수와 흡광도간의 선형관계와 최적 실험조건을 확인한 이후 시행하였다. 이 기법은 방사선을 조사받은 세포에서는 지수적 성장을 회복한 이후와 방사선을 조사받지 않은 세포는 4회 이상의 세포분열을 거친 후에 시행하였다. 세포집락 측정기법 및 MTT기법을 통하여 얻은 세포 생존율을 구한 후 이를 지표로 비교하였다. 결과 : 각 기법으로 얻은 세포 생존율의 표준편차는 $5\%$ 내외였다. 2가지 방법으로 구한 세포 생존율은 t-test로 비교하였을 때 $0\~4\;Gy$에서는 통계적으로 유의한 차이가 없었으며 회귀분석 결과는 선형적 관계가 있었다$(R^2=0.975-0.992)$. MTT 기법의 시행에 최적인 세포수는 배양효율에 따라 다른 것으로 나타났는데, 배양효율이 $30\%$ 이상이면 300개 이하가, $30\%$ 미만인 경우는 $500\~1,000$개가 적당한 것으로 확인되었다. MTT기법은 6 배가시간 경과 이후에 시행하는 것이 세포집락 측정기법과 가장 근접하였으며 적어도 4 배가시간 이후에 시행하는 것이 필요할 것으로 사료되었다. 이에 따르면 배가시간이 3일 이하인 세포주가 세포 민감성 측정방법으로서 MTT 기법이 세포 집락 측정 기법을 대체하여 사용하기에 적합한 것으로 사료되었다. 결론 : 이상에서, MTT기법을 이용하여 방사선조사 후의 세포생존을 측정하기 위해서는 예비실험을 통해 각 세포주에서의 최적의 조건을 찾는 것이 필수적이며 이 조건하에서 MTT기법을 시행해야만 방사선에 의한 세포 민감성 측정에 이용될 수 있음을 확인하였다.