• Korean Journal of Materials Research
• /
• v.5 no.6
• /
• pp.699-705
• /
• 1995

Effect of the grain boundary phases in Si$_3$N$_4$ ceramics on the fracture tonghness has been investigated. The Si$_3$N$_4$-Y$_2$O$_3$-SiO$_2$, (YS) and Si$_3$N$_4$-Y$_2$O$_3$-Al$_2$O$_3$(YA) systems were Can/HIP treated at 1750$^{\circ}C$ and then heat-treated at 1800∼2000$^{\circ}C$. The fracture toughness of the YA system, the grain boundary phase was only glass phase after heat-treatement, was increased. That of the YS system, however, the grain boundary phase was changed from crystalline and glass to glass phase after the heat -treatement above 1900$^{\circ}C$, was abruptly decreased. The reason of the sudden drop of the fracture toughness of the YS system was believed that the change of the grain boundary phases from crystalline and glass to glass phase effected un the fracture behavior.

• Journal of the Korean Ceramic Society
• /
• v.35 no.1
• /
• pp.11-16
• /
• 1998

$VO_2$ thin films have been prepared on borosilicate glass substrate using alkoxide method to characterize the effects of fabricating factors on thermochromic performance. The gel films formed by spin coating were converted to $V_2O_5$ phase during oxidizing heat-tratment and the $VO_2$ phase were formed by reducing heat-treatement. The thermochromic switching properties of $VO_2$ thin films are strongly affected by the crystal phase and microstructure and those could be controlled by reducing heat-treatment conditions. The ther-mochromic switching characteristics of $VO_2$ thin films synthesized were measured at IR (2.5$\mu\textrm{m}$) as the transition temperature of $63^{\circ}C$ the transition width of $3.6^{\circ}C$and the maximum and minimum transmittance of 84% and 14% respectively.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.35D no.3
• /
• pp.46-55
• /
• 1998

This stud demonstrates the profiles of heavy ions (As, Sb) in silicon by high energy (1~10 MeV) implantation. Implanted profiles were measured by SIMS (Cameca 4f) and compared with simulation results (TRIM) program and analytical description method using Pearson function). The experimental results have a little bit deviation with simulation data in the case of As high energy implatation. But in the case of Sb, the experimental results are in good agreement with TRIM data. SIMS profiles are perfectly fitted with a analytical description method only using one pearson function in Sb implantation. but in the case of As, fitted profilesshow with a little bit deviations by channeling effects of SIMS profiles. Thermal annealing for electrical activation of implanted ions was carried out by furnace annealing and RTA(Rapid Thermal Annealing). Concentration-depth profile after heat treatement were measured by SR(Spreading Resistance) method.

• Journal of the Korean Ceramic Society
• /
• v.33 no.6
• /
• pp.700-708
• /
• 1996

TiO2 membranes for microfiltration were prepared on $\alpha$-alumina support tube by slurry coating. The coating layer was obtained by flowing TiO2 slip on the inner surface of the alumina support. TiO2 membranes were heat-treated at 9$25^{\circ}C$ for 2 hrs. The thickness of the unsupported membrane was about 10${\mu}{\textrm}{m}$. The mean pore diameter of the membranes were 0.09 and 0.15${\mu}{\textrm}{m}$ respectively and the pure water flux was 900~1,200ι/m2.hr at room temperature and 1 bar. For a possible application of oily wastewater treatement an kerosene/wa-ter emulsion was separated in terms of flux and removal efficiency. In 60 min of operating time the flux of TiO2 membranes was 50~100 ι/m2.hr and removal efficiency was over 97% at 3kgf/cm2 of operating pres-sure and 600 ml/min of flow rate. TiO2 membranes could be recycled by reheat treatments at $600^{\circ}C$ for 2 hrs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07b
• /
• pp.1062-1065
• /
• 2003

본 연구에서는 초미세 $Y_2O_3:EU^{3+}$ 분말을 이용하여 나노 형광체를 제조하였다. 나노 형광체는 소량의 Eu가 도핑된 $Y_2O_3$ 재질로 구성되어 있다. 형광체 분말의 결정화를 위해 $500{\sim}900^{\circ}C$의 온도로 열처리하였다. 제조된 나노 형광체를 HRTEM으로 관찰한 결과 입자 크기가 열처리 온도에 따라 약 $4{\sim}30nm$의 분포를 나타내었다. 또한 XRD로 결정상을 분석한 결과 주로 입방정 구조로 되어 있고 소량의 단사정 구조가 포함된 $Y_2O_3$ peak가 검출되었다. EDS 분석 결과 약 $6.7{\sim}7.5%$의 Eu가 검출되었다. 약 4nm 크기의 $Y_2O_3:EU^{3+}$ 분말로 제조한 나노 형광체의 발광 특성은 주요 파장대가 612nm인 PL spectrum이 관찰되어, 적색 형광체로서의 $Y_2O_3:EU^{3+}$ 나노 분말이 제조되었다.

• The Journal of Pediatrics of Korean Medicine
• /
• v.29 no.2
• /
• pp.1-15
• /
• 2015

Objectives In the theory of Korean Medicine, Cicadae Periostracum (CP) has been used to treat skin diseases such as inflammatory dermatitis, tetanus and pruritus. CP can reduce heat and disperse wind. In prior studies, anti-allergic effect and anti-inflammatory effect of CP were reported. However, there has been no report regarding the correlation of CP and allergic contact dermatitis (ACD). This study was performed to show the effects of CP in ACD induced by 2,4-dinitrochlorobenzene (DNCB) in mice. Methods In this experiment, the effects of CP on biological changes were measured, such as changes in ear and spleen weight, ear and dorsum skin thickness, clinical aspect on the dorsum skin and histological changes. The effect of proliferation rate of splenocytes was also investigated in vitro and vivo study. Results In results, CP application (CPA) group and CP application and administration (CPAA) group were significantly restrained in ear weight gain and increase in ear and dorsum skin thickness compared to the control group. In addition, CPA and CPAA group showed diminished erythema, desquamation, bloodstain, and marks. Also, the histological assessment showed that CP treatement diminished thickness of epidermis, hyperkeratosis, pigmentation and parakeratosis. Conclusions In conclusion, these data suggest that CP can decrease symptoms of ACD.

• Journal of the Korean Society for Heat Treatment
• /
• v.5 no.2
• /
• 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.

• Journal of the Mineralogical Society of Korea
• /
• v.29 no.3
• /
• pp.103-111
• /
• 2016

Li-bearing hectorite, one member of trioctahedral smectite, occurred large in quantity and confirmed in Turkey western sedimentary boron deposit. Li-bearing hectorite attracted a particular attention because it is one of potential lithium resources. There have been no consensus for the change of hectorite due to heat and acid treatment although it is very important to use in industrial application. In this study, we examined changes of hectorite after heat and acid treatment as well as acid treatement followed by heating. We used clay ores collected in Bigadic deposit, which contained the highest $Li_2O$ content in Turkey boron deposits. Hectorite showed a strong endothermic reaction at $84^{\circ}C$ due to dehydration of absorbed water and interlayer water and a weak endothermic reaction above $600^{\circ}C$ owing to dehydration of crystallization water. The first endothermic reaction accompanied a large weight loss about 6%. Hectorite decomposed into enstatite, cristobalite and amorphous Fe material at $762^{\circ}C$ with exothermic reaction. When hectorite reacted with 3 kinds of 0.1 M acid during 1 hours, it had a good dissolution efficiency with $H_2SO_4{\geq}HCl$ > $HNO_3$ in order.

• The Korean Journal of Food And Nutrition
• /
• v.15 no.4
• /
• pp.331-336
• /
• 2002

Conformation of soymilk protein was examined to obtain basic information for improved calcium intolerence of soymilk protein partially hydrolyzed with protease. Surface hydrophobicities of three proteins showed the order of SMP(soymilk protein) < SPI(soy protein isolate) < PT-SMP(protease treated soymilk protein). Total thiol group contents of SMP and PT-SMP were similar but larger than that of SPI. Reducing rate of disulfide bond in PT-SMP after 2-mercaptoethanol treatment was laster than that in SMP. And so, this result indicates that PT-SMP may be less compacting due to protease treatement. From circular dichroism result, PT-SMP showed different pattern from SMP and SPI suggesting change of secondary structure by hydrolysis. And analysis of heat denaturating property by DSC showed that denaturation enthalpy of three proteins were all small. Especially enthalpy of PT-SMP was least, and this result suggested that PT-SMP was denatured easily by heating due to less compacting structure.

• Journal of Acupuncture Research
• /
• v.17 no.3
• /
• pp.10-24
• /
• 2000

1. Objectives : Millions of people throuout the world are affected by some form of dry eye disorder. I made researches for more effective treatments for dry eye. 2. Methodes : I refered to occidental and oriental medical records. 3. The results were as follows : Common symptoms of dry eye are dryness, burning, irritation, grittiness, itching, fatigue of eye, photophobia, congestion, mattering and tear. Treatments of dry eye are to clear away heat and fire, remove dampness, replenish Um and promote production of body fluid, tonify the blood and replenish Ki. Acupunctre and moxibustion therapy of dry eye are as follows: Very busy points of traditional regular acupuncture are Sangsong, Chanjuk, Sajukkong, Chongmyong, Sabaek, Tongjaryo, Taeyang, Pungji, Tuimup, Paekoe, Un-gyo, Chonjong, Hapkok, Yangbaek, Kansu, Yanggye, Imup, Chok-samni, Taechung, Kwangmyong, Yang-gok, Uihui, Chohae, Haenggan. Less busy points of it are Oyo, Kuhu, Sungup, Konmyong, Konmyongl, Konmyong2, Sangmyong, SanghaChongmyong, Shinmyong, Osang, Shinjong, Yonghyang, Yaemyong, Chon-yu, Chon-ju, Kwallye, Naebi, Noeho, Tuyu, Mokchang, Ponshin, Shinhoe, Yepung, Okchim, Pungbu, Kokchon, Kollyun, Nae-gwan, Tae-nung, Samumgyo, Sokolkong, Shinsu, Um-gyo, Igan, Chongok, Choktaek, Kyonjungsu, Kokchi, Kongchoe, Kyuum, Kihae, Taekolkong, Taedon, Pino, Pisu, Sabong, Samgan, Kokchi, Shinmun, Shinmaek, Shimsu, Yangno, Aengmun, Yolgyol, Oegwan, Wijung, Chang-gan, Chungjo, Chungdo, Chigu, Chium, Chollyo, Tongni, Pungmun, Haryom. Very busy points of ear-acupuncture are Kan, Bi, Shin, An, Less busy points of it are Shim, Pye, Naebunbe, Mok1, Mok2, Shinmun, Ichom. Useful points of bleeding by needle are Taeyang meridian, Yangmyong meridian, Chono, Chonjong, Paekoe, Sangsong, Chanjuk, Sajukkong, nasal cavity. Useful points of moxibustion are Inchung, Huaryo, Shinchu, Pungmun, Kansu, Shimsu, Kokchi, Kongchoe, Sohae.