• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.207-207
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• 2011

Amorphous transparent oxide semiconductors (a-TOS) have been widely studied for many optoelectronic devices such as AM-OLED (active-matrix organic light emitting diodes). Recently, Nomura et al. demonstrated high performance amorphous IGZO (In-Ga-Zn-O) TFTs.1 Despite the amorphous structure, due to the conduction band minimum (CBM) that made of spherically extended s-orbitals of the constituent metals, an a-IGZO TFT shows high mobility.2,3 But IGZO films contain high cost rare metals. Therefore, we need to investigate the alternatives. Because Aluminum has a high bond enthalpy with oxygen atom and Alumina has a high lattice energy, we try to replace Gallium with Aluminum that is high reserve low cost material. In this study, we focused on the electrical properties of IZO:Al thin films as a channel layer of TFTs. IZO:Al were deposited on unheated non-alkali glass substrates (5 cm ${\times}$ 5 cm) by magnetron co-sputtering system with two cathodes equipped with IZO target and Al target, respectively. The sintered ceramic IZO disc (3 inch ${\phi}$, 5 mm t) and metal Al target (3 inch ${\phi}$, 5 mm t) are used for deposition. The O2 gas was used as the reactive gas to control carrier concentration and mobility. Deposition was carried out under various sputtering conditions to investigate the effect of sputtering process on the characteristics of IZO:Al thin films. Correlation between sputtering factors and electronic properties of the film will be discussed in detail.

• 한국분말재료학회지
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• 제21권3호
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• pp.215-221
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• 2014

Translucent alumina is a potential candidate for high temperature application as a replacement of the glass or polymer. Recently, due to the increasing demand of high power light emitting diode (LED), there is a growing interest in the translucent alumina. Since the translucent property is very sensitive to the internal defect, such as voids inside or abnormal grain growth of sintered alumina, it is important to fabricate the defect-free product through the fabrication process. Powder injection molding (PIM) has been commonly applied for the fabrication of complex shaped products. Among the many parameters of PIM, the flowability of powder/binder mixture becomes more significant especially for the shape of the cavity with thin thickness. Two different positions of the gate were applied during PIM using the disc type of die. The binder was removed by solvent extraction method and the brown compact was sintered at $1750^{\circ}C$ for 3 hours in a vacuum. The flowability was also simulated using moldflow (MPI 6.0) with two different types of gate. The effect of the flowability of powder/binder mixture on the microstructure of the sintered specimen was studied with the analysis of the simulation result.

• 대한치과보철학회지
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• 제44권4호
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• pp.466-476
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• 2006

Purpose : Colonization of denture soft lining materials by Candida albicans can result in clinical problem, and deterioration of the materials. This study aimed to compare the retention and penetration of C. albicans into four denture soft lining materials commonly used. Materials and methods : Four denture soft lining materials (Coe-comfort$^{(R)}$, Coe-soft$^{(R)}$, GC soft liner$^{(R)}$, and Tissue conditioner$^{(R)}$) discs were prepared to glass slide and dental stone. Adherence of yeast to surfaces was monitored after one hour incubation of standardized washed cell suspension with test disc surfaces. Adherent cells stained with acridine orange were counted fluorescence microscopy. Penetration of yeast into materials bonded with acrylic resin after 1, 2, 3,4, 5, 6 and 7 days incubation was observed through sections stained using acridine orange and estimated to quantitative analysis using radioisotope. Results : There was statistical significance in cell numbers between smooth and rough surfaces(p<0.05). Higher numbers of cells were observed on rough surfaces. There was statistical significance in adherent cell numbers into smooth and rough surfaces individually(p<0.05). According to the increase of incubation periods, the cells penetrated into denture soft lining materials were shown to increase. The differences among all kinds of soft liner were statistically significant(p<0.05),and the largest number of cells penetrated into soft liners was observed in the Coe-soft$^{(R)}$. Conclusion : Initial adherence and penetration of yeast into denture soft lining materials has been influenced by surface roughness and chemical composition of them. The selection of appropriate materials and their fabrication may promote clinical performance.

• Korean Chemical Engineering Research
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• 제48권6호
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• pp.700-703
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• 2010

본 연구에서는 두충나무, 황벽나무 등을 포함하는 수목추출물의 소재특성을 시험하여 화장품 및 피부질환 치료소재로서의 응용 가능성을 조사하였다. 수목추출물의 항산화력은 DPPH 자유라디칼 소거법으로 측정되었으며 저농도에서는 항산화력이 낮았으나, $1000{\mu}g/ml$의 고농도에서는 우수한 항산화제인 비타민 C와 유사하였다. 항균력은 원판확산법으로 측정되었으며, 수목추출물은 피부상재균인 Staphylococcus epidermidis에 대해서는 낮은 항균력을 보이지만, 여드름 유발균인 Propionibacterium acne에 대해서는 높은 항균력을 보여주는 선택성 항균력이 있어, 여드름소재로서 매우 우수한 특성을 나타내었다. 무모생쥐를 이용한 항아토피 시험결과, 수목추출물은 DNCB에 의해 유도된 피부염증을 14일 째 거의 정상상태로 회복시켰으며, 피부내 항체인 IgE의 농도도 대조군에 비해 16% 낮추어주어 항아토피 효과가 우수한 것으로 나타났다. 따라서 수목추출물은 항여드름효과 및 항아토피 효과가 뛰어나서 화장품 혹은 피부질환 치료소재로서 응용 가능성이 매우 높음을 알 수 있었다.

• Transactions on Electrical and Electronic Materials
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• 제8권2호
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• pp.67-72
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• 2007

High Pressure Micro Jet (HPMJ) pad conditioning system was investigated as an alternative to diamond disc conditioning in copper CMP. A series of comparative 50-wafer marathon runs were conducted at constant wafer pressure and sliding velocity using Rohm & Haas IC1000 and Asahi-Kasei EMD Corporation (UNIPAD) concentrically grooved pads under ex-situ diamond conditioning or HPMJ conditioning. SEM images indicated that fibrous surface was restored using UNIPAD pads under both diamond and HPMJ conditioning. With IC1000 pads, asperities on the surface were significantly collapsed. This was believed to be due to differences in pad wear rates for the two conditioning methods. COF and removal rate were stable from wafer to wafer using both diamond and HPMJ conditioning when UNIPAD pads were used. Also, HPMJ conditioning showed higher COF and removal rate when compared to diamond conditioning for UNIPAD. On the other hand, COF and removal rates for IC1000 pads decreased significantly under HPMJ conditioning. Regardless of pad conditioning method adopted and the type of pad used, linear correlation was observed between temperature and COF, and removal rate and COF.

• Restorative Dentistry and Endodontics
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• 제27권3호
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• pp.257-269
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• 2002

Objective : The purpose of this study was to evaluate the resin infiltration into dentin of one-bottle adhesive systems and self-etching primer bonded to Class V cavities using confocal laser scanning microscope(CLSM). Material and Methods : Forty Class V cavities were prepared from freshly extracted caries-free Human teeth. These teeth were divided into two groups based on the presence of cervical abrasion: Group I, cervical abrasion : Group II, wedge-shaped cavity preparation. Resin-dentin interfaces were produced with two one-bottle dentin bonding systems-ONE COAT BOND(OCB; Coltene$^R$) and Syntac$^R$SPrint$^{TM}$(SS; VIVADENT)-, one self-etching priming system-CLEARFIL$^{TM}$ SE BOND (SB : KURARAY)- and one multi-step dentin bonding system-Scotchbond$^{TM}$Multi-Purpose (SBMP, 3M Dental Products)-as control according to manufacturers' instructions. Cavities were restored with Spectrum$^{R}$(Dentsply). Specimens were immersed in saline for 24 hours and sectioned longitudinally with a low-speed diamond disc. The resin-dentin interfaces were microscopically observed using CLSM. The quality of resin-infiltrated dentin layers were evaluated by five dentists using 0~4 scale. Results : Confocal laser scanning microscopal investigations using primer labeled with rhodamine B showed that the penetration of the primer occurred along the cavity margins. Statistical analysis using one-way ANOVA followed by Duncan's Multiple Range test revealed that the primer penetration of the group 2(wedge-shaped cavity preparation) was more effective than group 1(cervical abrasion) and that of the gingival interfaces was more effective than the occlusal interfaces. In the one-bottle dentin bonding systems, the resin penetration score of OCB was compatible to SBMP, but those of SS and self-etching priming system, SB were lower than SBMP.

• 대한본초학회지
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• 제32권1호
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• pp.75-81
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• 2017

Objectives : The present study was designed to investigate effects of mixed extracts (9:1, v/v) of Hwangryunhaedoktang, Chamaecyparis obtusa essential oil. We evaluated the antimicrobial and antioxidant activity by manufacturing mixed extracts as the materials for functional medicinal herb cosmetics. Methods : We performed antimicrobial were tested microbes (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Candida albicans, Propionibacterium acnes) by disc diffusion method and measure clear zone. Antioxidant activities were measured by DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity. Results : Antimicrobial activities of mixed extracts against S. epidermideis, P. acnes, S. aureus, E. coli, and Candida. A were $10.9{\pm}3.0mm$, $16.9{\pm}2.0mm$, $9.2{\pm}2.0mm$, $10.3{\pm}1.0mm$, $11.8{\pm}3.0mm$ respectively. The Chamaecyparis obtusa essential oil had the highest antimicrobial activities against S. epidermideis, P. acnes, S. aureus, E. coli, and Candia. A and clear zone of microbes ware $16.7{\pm}3.0mm$, $28.8{\pm}0.2mm$, $15.9{\pm}2.0mm$, $11.5{\pm}1.0mm$, $16.3{\pm}3.0mm$. Hwangryunhaedoktang extract showed antimicrobial activity but only P. acnes and S. aureus The antioxidant activities of the mixed extracts were tested through the evaluation of DPPH radical scavenging activity. The 100 % mixed extracts were found to have 90 % DPPH radical scavenging activity. The mixed extracts was presented similar antioxidant activities compared with that of ascorbic acid. As a result, A mixture extract is expected to have antimicrobial effects and free radical scavenging activity was found. Conclusions : Accordingly, It can be concluded that mixed extracts has the potential to cosmetic material.

• Journal of Plant Biology
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• 제17권2호
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• pp.53-62
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• 1974

A study was made on the primary production of Lake Changjamot during the spring season of 1973 by menas of the oxygen method. The stratification of temperature and dissolved oxygen were formed in May with the stratified structure of phytoplankton. The range of Secchi disc transparency was from 0.8m to 2.3m during the nine months of this investigation, which was begun in January, 1973. The value was lowest in early June when the phytoplankton blooming reached the peak. The concentration of PO4-P, NH3-N, NO3-N and NO3-N was reduced at the beginning of the phytoplankton blooming and increased again after May except PO4-P. It might have been caused by the inflow of the nitogenous fertilizer from the surrounding agricultural area since May when farming was started. The total amount of chlorophyll-a in the entire water column varied from 25mg/$m^2$ to 277mg/$m^2$ from January till September with the maximum value occurring in early June. These values show a considerable eutrophication of the in comparison with the data obtained in 1969. The daily gross production in the lake varied from a low of 655mgC/$m^2$ to a high of 2,859 mgC/$m^2$ during the spring season and this corresponds to the variation of the amount of chlorophyll. The total amount of daily respiration varied from 650mg C/$m^2$ in winter to 2,307 mg C/$m^2$ in late spring and exceeds gross primary production especially in late May showing the negative balance of daily production and consumption of organic material at that time. In conclusion, Lake Changjamot is a fairly productive and a moderately autotrophic lake and has been eutrophicated much during the past four years.

• The Journal of Advanced Prosthodontics
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• 제1권1호
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• pp.26-30
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• 2009

STATEMENT OF PROBLEM. Qualitative and semi-quantitative methods have been developed for TMJ sound classification, but the criteria presented are completely inhomogeneous. Thus, to develop more objective criteria for defining TMJ sounds, electroacoustical systems have been developed. We used Joint vibration analysis in the BioPAK system(Bioresearch Inc., Milwaukee, USA) as the electrovibratography. PURPOSE. The aim of this study was to examine the TMJ sounds with repect to frequency spectra patterns and the integral > 300 Hz /< 300 Hz ratios via six-months follow-up. MATERIAL AND METHODS. This study was done before and after the six-months recordings with 20 dental school students showed anterior disk displacement with reduction. Joint vibrations were analyzed using a mathematical technique known as the Fast Fourier Transform. RESULTS. In this study Group I and Group II showed varied integral > 300 /< 300 ratios before and after the six-months recordings. Also, by the comparative study between the integral > 300 /< 300 ratios and the frequency spectrums, it was conceivable that the frequency spectrums showed similar patterns at the same location that the joint sound occurred before and after the six-months recordings. while the frequency spectrums showed varied patterns at the different locations that the joint sound occurred before and after six-month recordings, it would possibly be due to the differences in the degree of internal derangement and/or in the shape of the disc. CONCLUSIONS. It is suggested that clinicians consider the integral > 300 /< 300 ratios as well as the frequency spectrums to decide the starting-point of the treatment for TMJ sounds.

• 환경생물
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• 제25권2호
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• pp.88-93
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• 2007

2006년 5월부터 10월까지 국내 농생태계 49지점에서 탐색 수집된 지렁이는 3과 5속 15종 1,846 개체이며 종 구성은 다음과 같다. Amynthas agrestis 20.9%, Amynthas koreanus 20.3%, Amynthas heteropodus 15.4%, Amynthas sp. 8.7%, Drawida japonica 8.0%, Eisenia fetida 7.2%, Amynthas hilgendorfi 7.0%, Bimastos parvus 3.2%, Amynthas hupeiensis 2.5%, Aporrectodea caliginosa 1.8%, Amynthas corticis 1.8%, Aporrectodea tuberculata 1.3%, Eisenia andrei 1.2%, Amynthas sp.20.4%, Amynthas sp. 1 0.3%이다. 종 조성 비율을 보면 이와 같이 왕지렁이속, A. agrestis, A. koreanus, A. heteropodus 3종이 차지하는 개체수는 1,046개체로 전체의 약 56.7%를 차지하는 우리나라 농생태계의 우점종 이다. 성숙 개체와 미성숙 개체의 비율은 1.25:1로 성숙된 개체가 더 많이 출현하였다. Amynthas sp. 1, Amynthas sp. 2는 본 조사를 통하여 처음으로 확인되는 신종 후보로, 여러 외부형질, 특히 malepore의 형태가 지금가지 국내에서 기록된 다른 왕지렁이속에 속하는 종들과는 확연히 구별되는 특징을 갖고 있다.