• 한국분말재료학회지
• /
• 제9권6호
• /
• pp.455-462
• /
• 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.

• 열처리공학회지
• /
• 제5권2호
• /
• pp.103-110
• /
• 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
• /
• 제31권4호
• /
• pp.218-224
• /
• 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.

• 혜화의학회지
• /
• 제14권2호
• /
• pp.143-151
• /
• 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
• /
• 제10권2호
• /
• pp.96-105
• /
• 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.

• 한국콘텐츠학회논문지
• /
• 제9권10호
• /
• pp.451-463
• /
• 2009

본 연구의 목적은 태양전지의 변환효율을 높이기 위한 박막형 소재 물질 개발과 전지의 조립과정을 개선 발달시키기 위한 것이다. 이 연구에 사용된 이산화티타니움은 물과 알콕사이드 몰비, 용액 pH의 변화, 분말의 묵힘조건 등 반응조건을 조절한 솔-겔 방법에 의하여 조제되었다. 준비된 이산화티타니움은 $300{\sim}750^{\circ}C$의 열처리조건 범위에서 소결하였다. $600^{\circ}C$의 열조건에서 만들어진 이산화티타니움은 XRD 패턴에서 강한 세기의 아나타제형이 나타났고, $750^{\circ}C$에서 소결되었을 때에는 아나타제형와 루틸형의 혼합물이 나타났다. 또한 소결온도와 묵힘시간 등에 따라 합성된 이산화티타니움의 특성은 묵힘시간이 증가함에 따라 아나타제형 결정으로 변환되는 것을 확인할 수 있었다. 한편 전류밀도는 묵힘시간과 온도에 따라 증가하였고, 변환효율은 전류밀도의 증가로 역시 증가함을 알 수 있었다. 산소분위기하에서 산소와 카드뮴텔루라이드의 화학결합이 생성됨을 관찰할 수 있었고, 카드뮴텔루라이드의 박막위의 산소가 크롬메이트와 하이드라진 처리에 의하여 감소되는 것을 알수 있었다. 결론적으로 공기분위기하에서 $550^{\circ}C$의 급속 소결조건에서 만들어진 카드뮴텔루라이드의 에너지변환효율은 $0.07cm^2$, $1.0cm^2$의 면적에 대해 각각 12.0%, 6.0%로 나타내었다.

• 한국식품영양과학회지
• /
• 제20권5호
• /
• pp.447-454
• /
• 1991

쇠고기 단백질 소화에 미치는 마늘의 영향을 검토하기 위해 마늘첨가량, 숙성기간에 따른 효소소화율 및 소화저해물질(Trypsin Inhibitor, TI)의 변화를 실험하였다. 또한 효소 가수분해물의 gel여과 및 가용성부분의 질소량을 정량하여 단백질의 구조 변화를 확인하였으며, 소화율과 아미노산조성 결과를 토대로 예측소화율(Predicted Digestibility, P-dig.), 계산단백효율비(Computed Protein Efficiency Ratio, C-PER) 및 분별계산단백효율비(Discriminant Computed Protein Efficiency Ratio, DC-PER)를 계산하여 단백질 품질을 평가하였다. 쇠고기단백질 소화율은 첨가되는 생마늘량에 약간 영향을 받으나 최적 참가량은 첨가 후의 가열조건에 의하여 결정된다($96{\pm}1^{\circ}C$, 20분 가열시 쇠고기 : 마늘=100g : 12g, 60분 가열시 쇠고기 : 마늘=100g : 3g) 열변성된 쇠고기에 대한 생마늘의 효과는 없고, 날쇠고기육의 소화에는 생마늘의 효과만 인정되며 이미 가열된 쇠고기육의 소화에는 영향을 미치지 못하였다. 날쇠고기를 $4~6^{\circ}C$에서 숙성시켰을 때, 최대의 소화율을 나타내는 시간은 마늘 첨가량에 따라 달라 날쇠고기 100g에 마늘 3g을 첨가할 경우에는(A) 8시간, 12g일 경우에는(B) 12시간이었다. 마늘과 함께 숙성시킨 쇠고기육은 (A)의 경우 $96{\pm}1^{\circ}C$에서 80분, (B)의 경우 20분 정도 가열했을 때 최대소화율을 나타내었다. Four-enzyme으로 가수분해한 숙성시료에는 2,200 dalton 정도의 저분자량의 peptid가 생성되어 소화가 용이함을 확인했으며, 가용성부분도 소화율에 비례하여 증가하였다. 효소소화율에 비례하여 C-PER은 증가하여 C-PER 2.14(날쇠고기)에서 2.50(마늘과 함께 숙성시킨 시료)로 품질이 개선되었다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
• /
• pp.55-61
• /
• 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.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 춘계학술대회논문집A
• /
• pp.49-54
• /
• 2000

Cr-Mo-V steel is widely used as a material for the turbine structural component in fossil power plants. It is well known that this material shows the various material degradation phenomenons such as temper embrittlement, carbide coarsening. and softening etc. or ins to the severe operation conditions as high temperature and high pressure. These deteriorative factors cause tile change of mechanical properties as reduction of fracture toughness. Therefor it is necessary to evaluate tile extent of degradation damage for Cr-Mo-V steel in life assessment of turbine structural components. In this paper. the electrochemical potentiokinetic reactivation(EPR) test in $50wt%-Ca(NO_3)_2$ solution is performed to develop the newly technique for degradation damage evaluation of Cr-Mo-V steel. The results obtained from the EPR test are compared with those in small punch(SP) tests recommended by semi-nondestructive testing method using miniaturized specimen. The evaluation parameters used in EPR test are tile reactivation current density$(I_R)$ and charge$(Q_{RC})$ reactivation rate$(I_R/I_{Crit},\;Q_R/Q_{Crit})$. The results suggest that $I_R/I_{Crit}$ in these parameters shows a good correlation with SP test results.

• 대한기계학회논문집A
• /
• 제20권9호
• /
• pp.2819-2832
• /
• 1996

The estimation of the remaining life for the aged components in power plant as well as chemical and petroleum plants has been recently concerned. The raw materials used in this study are the 1Cr-1Mo-0.25V steel which intensified P and S compositions along with the nominal compositions of ASTM A 470 standard. Five kinds of specimens with the different degradation levels were prepared by isothermal aging heat treatment at 630.deg.C. The mechanical properties and rotated bending fatigue strength of virgin and aged 1Cr-1Mo-0.25V steel have been investigated through the hardness, tensile, fatigue test, SEM fractograph and EDS analysis at 538.deg.C and room temperature, respectively. Thus the data of aged specimens were compared with those of virgin specimen to evaluate the aging effects. The main results obtained in this study are as follows ; The decrease of the yield and tensile strength due to degradation was distinguished until 50, 000hrs simulated service time. And it was confirmed that the considerable amount of P, Mn, Cr and S was precipitated at the grain boundary of aged material through the SEM and EDS analysis. The rotated bendingd fatigue strength at 538.deg.C of virgin, 25, 000, 50, 000, 75, 000 and 100, 000 hrs aged material was decreased 44.6 %, 49.6 %, 51.5 %, 52.4% and 53.8% than that of virgin material at 10$_{7}$cycles of room temperature, respectively. The major cracks of virgin and aged materials mainly initiated at the inclusions including Si, P and Mn compositions which were located at the outer periphery of the specimen.n.