• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.173-177
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• 2013

The purpose of this paper is to investigate the influences on mechanical properties of two-stroke cycle motor pistons manufactured by casting, conventional forging and powder forging, through the comparison of characteristics, merits and disadvantages of each forming technology. For each forming technology, the optimal process parameters were determined through the experiments for several conditions, and microstructure, hardness, tensile strength and elongation of pistons are compared and analyzed. In conventional forging process, material temperature was $460^{\circ}C$ and the die temperature was $210^{\circ}C$ for the Al 4032. The optimal condition was found as solution treatment under $520^{\circ}C$ for 5 hours, quenching with $23^{\circ}C$ water, and aging under $190^{\circ}C$ for 5 hours. In powder forging process, the proper composition of material was determined and optimal sintering conditions were examined. From the experiment, 1.5% of Si contents on the total weight, $580^{\circ}C$ of sintering temperature, and 25 minutes of sintering time were determined as the optimal process condition. For the optimal condition, the pistons had 76.4~78.3 [HRB] of hardness, and 500 [MPa] of tensile strength after T6 heat treatment.

• Journal of Powder Materials
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• v.9 no.6
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• pp.455-462
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• 2002

The microstructures and properties of TiC dispersed nickel-base alloy were studied in this work. The alloy prepared by powder metallurgical processing was solution treated, 1st-aged at $880^{\circ}C$ for 16 hours, and then 2nd-aged at $760^{\circ}C$ for 4 hours. Microstucture of sintered specimen showed that TiC particles are uniformly dispersed in Ni base alloy. In the specimen aged at $880^{\circ}C$ for 8 hours, the fine $\gammaNi_3$(Al,Ti) precipitates with round shape are observed and the very fine $\gammaNi_3$(Al,Ti) particles with round shape are precipitated in the specimen aged at $760^{\circ}C$ for 4 hours. The presence of ${\gamma}$precipitates in TiC/Ni base alloy increased the hardness and wear resistance of the specimen. The hardness and wear resistance of the Ni-base with TiC are higher than those of conventional Ni-base superalloy X-750 because of dispersion strengthening of TiC particles. The hardness, transverse rupture strength and resistance of the specimen 2nd-aged at $760^{\circ}C$ for 4 hours are higher than those of 1st-aged specimen due to ultrafine $\gammaNi_3$(Al,Ti) precipitates.

• Journal of the Korean Society for Heat Treatment
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• v.5 no.2
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• pp.103-110
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• 1992

This study is aimed to investigate the effect of various thermomechanical treatments($T_6$, $T_8$ and ITMT) on the microstructure and mechanical properties of an Al-Cu-Li-Ag-Mg-Zr alloy (Weldalite 049) which has been known to strong natural aging response, good weldablity and high strength in $T_6$ sand $T_8$ temper. This experiment was performed by means of differential scaning calorimetry, tensile test, optical and transmission electron microscopy. The tensile strength in the peak aged condition shows 620, 650 MPa in $T_6$ and $T_8$(40% cold work), respectively. Also, The tensile strength is increased with cold working in $T_8$ but decreased at 60% cold working. However, the tensile strength of the intermediate thermomechanical treated speciman(ITMT) is lower than that of $T_6$ temper about 20% but the elongation is higher than two times. It might be predicted that the ITMT is effective processing to improve the toughness of this alloy. In $T_6$, $T_8$ and ITMT, the major strengthening phase is $T_1(Al_2CuLi)$ phases. and the fine $T_1$ phase which are homogeneously precipited in matrix was observed much more in $T_8$ than $T_6$ and ITMT.

• Korean Journal of Acupuncture
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• v.31 no.4
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• pp.218-224
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• 2014

Objectives : Zizyphus jujuba fruits(ZJF), a traditional Korean medicine has various biological activities such as anti-inflammatory, anti-oxidative and neuro-protective effects. However, it is still unclear whether ZJF has any biological effect on anti-aging. In this study, we examined the effect of ZJF on lifespan and thermal stress in C. elegans. Methods and Results : ZJF water extracts were fermented for 7 days(F7-ZJF) and 14 days(F14-ZJF) by Laetiporus sulphureus to increase secondary metabolites such as aglycone of flavonoids and terpenoids. In the lifespan assay, ZJF water extracts and fermented ZJF were treated on the agar medium plate with age synchronized egg stage of C. elegans. Treatment of F7-ZJF-$200{\mu}g/mL$ with OP-50 E. coli and F14-ZJF-$200{\mu}g/mL$ with OP-50 E. coli significantly increased life span of C. elegans(N2) at thermal stress condition of $25^{\circ}C$. Moreover mRNA levels of lifespan associated HSP 16.1, HSP 70, and HSF-1 were increased at thermal stress condition of $25^{\circ}C$. However, in the equilibration temperature of $20^{\circ}C$ after stress condition of $35^{\circ}C$ for 2 hr, F-14-ZJF-$200{\mu}g/mL$ treatment decreased the levels of heat shock protein in hsp16.2/GFP C. elegans. Conclusions : Our study indicates that prolong role of fermented-ZJF in C. elegans is mediated by control HSPs production.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.4
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• pp.439-445
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• 2001

The destructive method is reliable and widely used lot the estimation of material degradation but, it have time-consuming and a great difficulty in preparing specimens from in-service industrial facilities. Therefore, the estimation of degraded structural materials used at high temperature by nondestructive evaluation such as electric resistance method, replica method, Barkhausen noise method, electro-chemical method and ultrasonic method are strongly desired. Ultrasonic nondestructive evaluation technique has been reported good to attain efficiency of measurement, high sensitivity of measurement, and rapidity and reliability of result interpretation. In this study, it was verified experimentally the feasibility of the evaluation of degraded 2.25Cr-1Mo steel specimens which were prepared by the isothermal aging heat treatment at $630^{\circ}C$ by high frequency longitudinal wave method investigating the change of attenuation coefficient by FFT analysis and wavelet transform. Because of carbide precipitation increase and spheroidization near grain boundary of microstructure to aging degradation, attenuation coefficient had a tendency to increase as degradation proceeded. It was identified possibly to evaluate degradation using the characteristics of high-frequency ultrasonics. Frequency dependence of ultrasonic attenuation coefficient to aging degradation appeared large, which made sure that attenuation coefficient is an important parameter for evaluation of aging degradation.

• Journal of Haehwa Medicine
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• v.14 no.2
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• pp.143-151
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• 2005

Gobjectives and Methods to investigate into the course of incurable and relapse renal stones' differentiation of symptoms and signs and to effectively improve treatment of incurable and relapse renal stones through Oriental Medicine. To search for the papers about treatment of incurable and relapse renal stones from 1994 till 2004, and re-search papers about treatment for indicated differentiation of disease. Result and conclusions : 1. It is the kidney vacuity additionally the deficiency of qi(氣) in middle-burner that the incurable and relapse renal stones' differentiation of disease. 2. The cause is taking an overdose of attacking renal stones to eliminate dampness and heat medicine, aging, chrome disease. a sex act excess, insufficiency of congenital qi(氣), insufficient exercise, wrong treatment and stress. 3. Herb medicines are constituted supplementing kidney drugs for inhibition of renal stone's creation, drugs to diuresis and dissolve calculi, and drugs 10 exclude stasis blood(瘀血) on account of renal stones. 4. Anti-renal stone measures me sufficiently drinking water, not eating greasy food. taking medicine for supplementing kidney, diuresis and dissolve calculi by periods, and drinking substitute water to boll down medical herb as Lysimachiae Herba (金錢草) Polygoni Avicularis Herba(篇蓄).

• Medical Lasers
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• v.10 no.2
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• pp.96-105
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• 2021

Background and Objectives Skin aging is reportedly associated with regulation in collagen and elastin synthesis. This study investigated the potential of combining light-emitting diode (LED) treatments using a 630-nm and 850-nm LED with simultaneous microcurrent application. Materials and Methods The dorsal skin of female pigs was treated with a home-use device. We examined the treatment effects using photography, thermocamera, microscopic pathology, and histological examination to determine the mechanism of action, efficacy, and safety of the procedure. A histological observation was performed using hematoxylin and eosin, Masson's trichrome, Victoria blue, and immunohistochemical staining. We also used the Sircol soluble collagen and elastin assay kit to measure the amounts of collagen and elastin in the porcine back skin tissue after 2 and 6 weeks. Results Evaluation by visual inspection and devices showed no skin damage or heat-induced injury at the treatment site. Histological staining revealed that accurate treatment of the targeted dermis layer effectively enhanced collagen and elastin deposition. Collagen type I, a protein defined by immunohistochemical staining, was overexpressed in the early stages of weeks 2 and 6. Combined therapy findings showed the superior capability of the 630-nm and 850-nm LED procedures to induce collagen; in contrast, elastin induction was more pronounced after microcurrent treatments. Conclusion The home-use LED device, comprising a combination of 630-nm and 850-nm LEDs and microcurrent, is safe and can be used as an adjunctive treatment for self-administered facial rejuvenation.

• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.451-463
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• 2009

The purpose of this research is to develop thin film materials and fabrication process for efficient $TiO_2$/CdTe solar cells. In this work photocatalyst titanium dioxide was prepared by sol-gel procedure according to reaction condition, the mole ratio of $H_2O$/TTIP, pH of solution and aging condition of powder. The prepared titanium dioxide was thermally treated from 300 to $750^{\circ}C$. Maximum intensity of anatase phase of titanium dioxide was achieved by calcination at $600^{\circ}C$ for 2 hr. And it was mixture of anatase and rutile phase when temperature of calcination was $750^{\circ}C$. It has been known that the properties of synthesized titanium dioxide according to aging time and calcination temperature was converted to anatase phase crystal on increasing of aging time. Also the current density has been increased with aging time and temperature, the efficiency has been increased with because of reason on above results. The formation of chemical bonding on oxygen and cadmium telluride under oxygen circumstances had been observed, and oxygen of thin film surface on cadmium telluride had been decreased with the treatment of chromate and hydrazine. As results had been shown that the energy conversion efficiency of cadmium telluride use by rapidly treatmented heat at the condition of $550^{\circ}C$ under air circumstance got 12.0%, 6.0% values according to $0.07cm^2$, $1.0cm^2$ surface area, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.5
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• pp.447-454
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• 1991

Chopped garlic was added to beef to determine its effect on the protein digestion during storage and heat treatment. The digestibility of raw beef without garlic was not significantly changed during storage at $4^{\circ}C$, but increased as garlic added and aging time increased. The optimal aging time and amount of garlic added was varied with heating time. Trypsin inhibitor did not change the digestibility of beef due to its thermal inactivation. Gel chromatography revealed that the lower molecular weight peptides(2,200~6,150 dalton) were shown in beef-garlic mixture through aging and heating procedure. When aged beef with garlic was digested with four-enzyme system, the soluble portion was increased significantly in comparison with that from raw beef without garlic. Protein quality of beef, as measured by computed PER(C-PER), was improved from 2.14 of raw beef to 2.50 of aged beef with chopped garlic.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05b
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• pp.55-61
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• 2002

Ultra-fine particles of $SnO_{2}$ was synthersized by the sol-gel powder processing using tin(II) chloride dihydrate$(SnCl_{2}{\cdot}2H_{2}O)$ and ethanol$(C_{2}H_{5}OH)$ as raw materials. Gel powders can be obtained by drying of sol at $120^{\circ}C$ after aging 72hrs and 168hrs. The amount of $SnO_{2}$ phase was increased with temperature because of the evaporation of volatile components, and the creation of $SnO_{2}$ phase was almost done by the heat treatment at $700^{\circ}C/30min$ The grain sizes after firing are about 20-30nm, and it showed the narrow distribution of grain size. The specimens to measure electrical properties were fabricated by the thick film screen printing technique on the alumina substrates. The conductance of $SnO_{2}$ was increased with temperature up to $380^{\circ}C$ by the typical conduction mechanism of semiconducting ceramics. There was a region of constant conductance between about $200^{\circ}C$ and $380^{\circ}C$ due to the increment of electron concentration with temperature and the annihilation of conduction carriers by the absorption and electron trapped-ionization of oxygen on the surface of $SnO_{2}$, It was finally showed the intrinsic behaviors above $450^{\circ}C$. The sensing properties of response time, recovery, and sensitivity of CO were improved with aging time.