• 한국표면공학회지
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• 제15권1호
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• pp.11-18
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• 1982

80% Ni-Permalloy is soft magnetic material with high initial permeability and low magnetic coercive force Hc, and is used to computer memory cores and minirelays of communication e-ngineering. In this paper 80 Permalloy thin film on copper cathode was alloy-deposited from Watts so-lution contatining FeSO4$.$7H2O. The amount of FeSO4$.$7H2O in the solution, pH, temperature of the solution and plating current density were varied as parameters and the resulting comp-osition changes of deposited film were analyzed electrochemically with respect to the parame-ters. From the above procedure electroplating conditions for deposition of 80 Permalloy were est-ablished as following: 17-21 g/$\ell$ of FeSO4$.$7H2O in Watts solution, current density 1.0-2.0 Amp/dm2, pH 2.5-3.0 and temperature range of 50-60$^{\circ}C$.

• 한국분말재료학회지
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• 제22권6호
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• pp.432-437
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• 2015

The en-riched $^{58}Ni$ powders are dissolved in acid solution and coated on a Cu target for proton irradiation at cyclotron to produce $^{57}Co$ radioisotope. The condition of the plating bath and the coating process are determined using the en-riched powders. To establish the coating conditions for $^{57}Co$, non-radioactive Co ions are dissolved in an acid solution and electroplated on to a rhodium plate. The thermal diffusion of electroplated Co into a rhodium matrix was studied to apply a $^{57}Co$ Mssbauer source. The diffusion depth from surface to matrix of Co is depended on the annealing temperature and time. The deposited Co atoms diffuse completely into a rhodium (Rh) matrix without substantial loss at an annealing temperature of 1200 for 4 hours.

• 한국표면공학회지
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• 제48권4호
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• pp.131-135
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• 2015

We investigated the surface morphology and the change of Ag concentration for SnAg electrodeposits according to the current density using labmade and commercial plating solutions. The concentration of Ag in the SnAg electrodeposits decreased with increasing the current density. The Ag concentrations at the conditions of over $50mA/cm^2$ were below 3 wt% and the surface was relatively smooth. Cu pillar bump was fabricated by using SnAg electroplating, and it was reflowed at $240^{\circ}C$ for 90 sec. The cross-sectional microstructure was investigated by using EBSD measurement and it was found that the grain size of SnAg became smaller by increasing the number of reflow treatments.

• 한국미생물·생명공학회지
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• 제13권2호
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• pp.145-149
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• 1985

전분자원의 효율적 이용을 위한 방법의 일환으로 분리동정된 전분이용성 효모 H. anomala var. anomala FRI YO-32와 S. cerevisiae와의 세포융합가능성을 검토하기 위하여, 두 효모원형질체의 재생을 위한 최적조건들이 검토되었다. S. cerevisiae에 비하여 FRI YO-32균주의 원형질체가 삼투압안정성이 더 좋았으며 원형질체 재생에 영향을 주는 중요한 인자로서 agar와 삼투압안정제의 농도, 원형 질체 배양방법 등이 검토되었다. 또한 원형 질체 형성을 위한 효소처리 시간이 길어질수록 원형 질체 형성수율은 증가하나 재생효율은 감소하였다.

• 한국표면공학회지
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• 제19권3호
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• pp.83-91
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• 1986

Codeposited of boron nitride(BN) particle dispersed into electroless nickel-phosphours (Ni-P) and nickel-boron(Ni-B) platings were studied for the purpose of developing the wear resistance and lubricity. BN can be codeposited from electroless nickel plating bath with $NaH_2PO_2$ and $NaBH_4$ as the reducing agents. Most dispersolids were distributed uniformly in the Ni-P and Ni-B matrix. Abrasion loss decreased with increasing amount of codeposits and reached a constant value 2.4 percent by volume percent of BN particle. The wear resistance and the friction coefficient of the heat treated BN composite coatings were improved about three times than that of as-coatings. The BN composite coatings were more wear resistance than hard chromium. Ni-B-BN composite coatings showed lower wear resistance and friction coefficient than Ni-P-BN. The BN content of the deposite was found to be 2.4 v/o for these optium conditions.

• Reproductive and Developmental Biology
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• 제30권3호
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• pp.163-167
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• 2006

The purpose of the present study was to establish culture conditions for the in vitro study of the neonatal piglet Sertoli cell. Isolation for the culture of Sertoli cell was established using collagenase and pancreatin digestion of testicular tissues. The effects of various culture media, fetal bovine serum(FBS), follicular stimulating hormone(FSH), epidermal growth factor(EGF) and insulin-transferrin-sodium selenite(ITS) on growth of neonatal piglet Sertoli cells were investigated. The mitogenic effects of Dulbecco's modified Eagle's medium+Ham's F-12 medium was higher than other media used in this experiment. The addition of 1% FBS in cultures was necessary for attachment of Sertoli cell clusters. However, except FBS and EGF, FSH and ITS did not stimulate Sertoli cell proliferation. When Sertoli cells isolated from neonatal piglets were cultured in Dulbecco's modified Eagle's medium+Ham's F-12 medium supplemented with 1% FBS, FSH EGF and ITS, the yield and plating efficiency of Sertoli cells were largely increased. Confluency of Sertoli cells was reached as early as 4 days of culture. The method described here reduces or eliminates many of the drawbacks of the conventional procedures used to isolate and culture of Sertoli cells, thus providing a useful tool in studies of growth kinetics and regulation of cell proliferation in vitro.

• 한국표면공학회지
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• 제27권4호
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• pp.193-206
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• 1994

A wear behavior of electroless (Ni-P-X, X: SiC, $Al_2O_3$, Diamond) composite coating layers, formed under various conditions on commerical grade low carbon steel, has been investigated using Taber abrasion tester and scanning electron microscope. Several factors, which are type of particles, co-deposited content, particle size, distribution of particles and heat-treatment, influenced the wear resistance. The wear resistance of the composited coating layers after heat-treatment at $400^{\circ}C$ for 1 hr was increased 70 times with diamond, 15 times with SiC and 8 times with $Al_2O_3$, compared with the electroless nickel plating layer without heat-treatment.

• 한국재료학회지
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• 제16권10호
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• pp.639-646
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• 2006

Over the last two decades, microbiologically influenced corrosion (MIC) of metallic materials has received considerable attention due to its serious effects on industrial field. In this context, it is important to devise control methods which inhibit biofilm formation on various metallic compounds and are compatible with environment. It was change of various conditions (duty cycle, current density, $AgNO_3$ concentration and pH) for injection of Ag particles in anodized Aluminum alloy pore using pulsed current. Optimal condition was obtained by means of FE-SEM, ICP analysis etc. The antibacterial metal's specimen were manufactured under optimal condition and this specimen were tested the antibacterial characterization and anticorrosion characterization. In result of test, we can confirmed that the antibacterial characterization and anticorrosion characterization of the specimens of injected Ag particles in anodized Aluminum alloy pore using pulsed current were better than the anodized Aluminum alloy specimens.

• 한국재료학회지
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• 제19권6호
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• pp.337-343
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• 2009

In this study, we optimized Pb-free Sn/Ni plating thickness and conditions were optimized to counteract the environmental regulations, such as RoHS and ELV(End-of Life Vehicles). The $B_{10}$ life verification method was also suggested to have been successful when used with the accelerated life test(ALT) for assessing Pb-free solder joint life of piezoelectric (PZT) ceramic resonator. In order to evaluate the solder joint life, a modified Norris-Landzberg equation and a Coffin-Manson equation were utilized. Test vehicles that were composed of 2520 PZT ceramic resonator on FR-4 PCB with Sn-3.0Ag-0.5Cu for ALT were manufactured as well. Thermal shock test was conducted with 1,500 cycles from $(-40{\pm}2)^{\circ}C$ to $(120{\pm}2)^{\circ}C$, and 30 minutes dwell time at each temperature, respectively. It was discovered that the thermal shock test is a very useful method in introducing the CTE mismatch caused by thermo-mechanical stress at the solder joints. The resonance frequency of test components was measured and observed the microsection views were also observed to confirm the crack generation of the solder joints.

• 한국표면공학회지
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• 제33권4호
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• pp.222-228
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• 2000

The life time of cutting tool was studied in the relation with the properties of TiN coating tools. The purpose of this study is to compare the cutting conditions of the TiN coated tools with those of the non-coated tools and to find out the optimal cutting condition of the TiN coated tool. The coated tools were prepared by the sputtering process at $4$\times$10^{-3}$Torr. When the cutting speed is increased 22.2% from 90m/min, the limited life of coating bite was decreased by 60.61%, but non-coating bite was decreased by 64.05%. In the tool lifetime equation of the coated tools "a"(exponent of feed rate) was not much changed in comparison with that of the non-coated tools but "n" (exponent of tool′s life) was increased by 9.3% and "b" (exponent of cutting depth) was increased by 2.4%. It was thought to be that TiN coated tools was used for higher cutting speed than non-coated tools to improve the lifetime of the coated tools.