• 대한한의학회지
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• 제19권1호
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• pp.165-178
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• 1998

This study was carried out to investigate the protective effects of GaMiHyangSaYukGunJaTang on gastric mucosal lesions caused by indomethacin in rats.The test group was injected with indomethacin after the oral administration of GaMiHyangSaYukGunJaTang, while the control group was injected only with indomethacin. The lipid peroxidation level increased considerably in the control group, but superoxide disnurtase(SOD), catalase and glutathione(GSH) levels remarkably decreased. The following effects induced by indomethacin were observed in the stomach of the control group; mucosa hemoIThagic infarct, mucosa cell necrosis, leukocyte appearance, mucosa hemorrhagic erosion and gastric pit disawearance. In the test group, lipid peroxides level was significantly reduced compared with the control group While SOD, catalase and GSH levels considerably increased. The following effects were also observed in the stomach of the test group; mucosa hemorrhagic infarct, mucosa cell necrosis, leukocyte appearance and mucosa hemorrhagic erosion occured far less and gastric pit disappearance was not observed at all. This results suggest that GaMiHyangSaYukGunJaTang is effective in the remedy of gastric mucosal lesions as GaMiHyangSaYukGunJaTang suppresses the production of the lipid peroxides and free radicals induced by indomethacin and activates SOD, catalase and GSH.

• 한국분말재료학회지
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• 제14권4호
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• pp.238-244
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• 2007

The electrophoretic deposition process of Ni nano-particles in organic suspension was employed for self-repairing of heat exchanger tubes. For this purpose, Ni nano-particles prepared by levitational gas condensation method were dispersed into the solution of ethanol with the addition of dispersant Hypermer KD2. For electrophoretic deposition of Ni nano-particles on the Ni alloy specimen, constant electric fields of 20 and 100 V $cm^{-1}$ were applied to the specimen in Ni-dispersed solution. It was found that as electrophoretic deposition proceeds, the size of the pit or crack remarkably decreased due to the agglomeration of Ni nano-particles at the pit or crack. This strongly suggests that the electrophoretic mobility of the charged particles is larger for the damaged part with a higher current value rather than outer surfaces with a lower current value.

• 한국표면공학회지
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• 제31권5호
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• pp.251-260
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• 1998

Stainless Steel is being used widely for various purposes due to its good corrosion resistance. There have been many researches to produce colored stainless steel by several methods such as anodizing and ion-plating. In this experiment, we $Ti_XN$(C,O) on the films SUS304, aluminium, and glass substrates with DC magentron sputterinng system made by Leybold Hereus, and strdied the structur, corrsion and pit characture of the TiXN observed by TeM image was black and whink and white columnar hed a very fine(200$\AA$) dense sturcture,and the diffraction resistance at the $3{\times}10_6A/\textrm{cm}^2$ and $10_{10}\times{cm}^2$current density were obtained in the under-stoichiometry $Ti_xN$ compound of Ar/$N_2$(Ar:$N_2$=100:6, titanium-rich compound) and the over-stoichiometry compound of Ar/$N_2$((Ar:$N_2$=60:15) respectively. When the thiness was over 1.64$\mu\textrm{m}$, good pit resistance could be obtained and its improvement was especially affected by perfect surfaceface. Typical TiN anodic polarzation curves of very unstable corrosion were observed by $Ti_xN$ film on the glass and perfect film of 3.28$\mu\textrm{m}$ thickness.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.125-125
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• 2010

극성 [0001] 방향으로 성장된 질화물 기반의 LED (light emitting diode) 는 분극현상에 의해 발생하는 강한 내부 전기장의 영향을 받게 된다. 이러한 내부 전기장은 양자우물 내의 전자와 정공의 공간적 분리를 야기하고 quantum confined Stark effect (QCSE)에 의한 발광 파장의 적색 편이가 발생하며 양자효율의 저하를 가져오게 된다. 이러한 문제를 해결하기 위해 InGaN/GaN이나 AlGaN/GaN 양자 우물구조를 GaN의 m-plane (1$\bar{1}$00) 이나 a-plane (11$\bar{2}$0) 등 비극성면 위에 성장하려는 시도를 하고 있다. 그러나 비극성 면의 비등방성 (anisotropy) 으로 인하여 결정성이 높은 비극성 GaN을 성장하는 데에는 많은 어려움이 있다. GaN 층의 표면을 평탄화하고 결정성을 향상시키기 위해서 저온 GaN 또는 AlN 버퍼층을 성장하는 2단계 방법이나 고온 버퍼층을 이용하여 성장하는 연구들이 많이 진행되고 있다. 본 연구에서는 고온 GaN 버퍼층을 이용하여 기존의 2단계 성장과정을 단순화한 비극성 a-plane GaN을 r-plane 사파이어 기판위에 유기금속 화학증착법 (MOCVD)으로 성장하였다. 사파이어 기판위에 AlN 층을 형성하기 위한 nitridation 과정 후 1030 도에서 두께 45 ~ 800 nm의 고온 GaN 버퍼층을 성장하고 총 박막 두께가 2.7 ~ 3 um 가 되도록 a-plane GaN을 성장하여 표면 양상의 변화와 결정성을 확인하였다. 또한 a-plane GaN 박막 성장 시에 성장 압력을 100 ~ 300 torr 로 조절하며 박막 성장의 변화 양상을 관찰하였다. 고온 GaN 버퍼층 성장 두께가 감소함에 따라 결정성은 증가하였으나 표면의 삼각형 형태의 pit 밀도가 증가함을 확인하였다. 또한 성장 압력이 감소함에 따라 표면 pit은 감소하였으나 결정성도 감소하는 것을 확인하였다. 성장 압력과 버퍼층 성장 두께를 조절하여 표면에 삼각형 형태의 pit이 존재하지 않는 RMS roughness 0.99 nm, 관통전위밀도 $1.78\;{\times}\;10^{10}/cm^2$, XRD 반가폭이 [0001], [1$\bar{1}$00] 방향으로 각 798, 1909 arcsec 인 a-plane GaN을 성장하였다. 이 연구를 통해 고온 GaN 버퍼 성장방법을 이용하여 간소화된 공정으로 LED 소자 제작에 사용할 수 있는 결정성 높은 a-plane GaN을 성장할 수 있는 가능성을 확인하였다.

• 한국결정학회지
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• 제7권1호
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• pp.73-80
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• 1996

단일 온도대역 수평 Bridgman(1-T HB)법에 의해 2인치 직경의 GaAs 단결정을 성장시키기 위하여 그 장치를 설계·제작하였고, undoped, Si-doped 및 Zn-doped 단결정을 성장하였다. 단결정성의 측면에서 성장횟수별 비로 0.73의 단결정성을 보였고, 격자결함 밀도(etch pit density)는 n-type의 경우 평균 5,000/cm2, p-type의 경우 10,000/cm2, 그리고 undoped의 경우 20,000/cm2 정도를 보였다. 한편 undoped GaAs 단결정의 경우, Hall 측정에 의한 carrier 농도가 ∼1×1016/cm3인 것으로 나타나 기존의 이중 온도대역(2-T : double temperature zone) 또는 삼중 온도대역(3-T : three temperature zone) 수평 Bridgman 방식에 비하여 Si 유입량이 절반 수준인 것으로 측정되었다. 따라서 1-T HB 방식에 의하여 2-T나 3-T HB 방법보다 나은 수율을 갖고 더 순도가 높은 GaAs 단결정을 성장시킬 수 있었다.

• 대한수의학회지
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• 제37권3호
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• pp.583-593
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• 1997

Indirect fluorescent antibody test(IFAT) and enzyme-linked imuunosorbent assay (IgG-ELISA) as serological diagnostic tools were conducted to evaluate the usefulness for diagnosis of canine babesiosis infected with Babesia gibsoni in domestic various dog breeds, american pit bullterrier, military shepherd, and mongrel dogs. The results obtained from this study were abstracted as follows. The nonionic detergent Triton X-100 and absorbent bio-bead $SM_2$ were useful reagents for the preparation of pure merozoite antigen of B gibsoni to be used in ELISA. The optimum reaction in ELISA was shown when the protein concentration of ELISA antigen was measured as 625ng/ml and the conjugate concentration was diluted into 1/6000 fold. The average OD value of ELISA in sera determined with negative responses in IFAT was measured as $0.255{\pm}0.051$(490nm) and the cut - off value of OD was determined as 0.399(490nm). The serum antibodies in both of IFAT and ELISA were detected on one week after artificially infected with B gibsoni and these high antibody titers, 512X in IFAT and 1024X in ELISA, were long lasted until 15 weeks after infection. The reproducibility of reaction and stability of the antigen absorbed microtitration polystyrene plate preserved in $4^{\circ}C$ refrigerator and $-20^{\circ}C$ freezer, respectively could be lasted until 135 days after storage. The positive rates in IFAT by dog breeds were shown 8.1%(60/744 heads) in mongrel dogs, 81.3%(78/96 heads) in american pit bullterrier and 15.6%(15/96 heads) in military shepherd, while the positive rate in ELISA shown 17.6%(131/744 heads) in mongrel dogs, 83.3%(80/96 heads) in american pit bullterrier and 36.5%(35/96 heads) in military shepherd, respiectively. In the total of 936 heads surveyed with IFAT and ELISA the positive rates in IFAT and ELISA were 16.4%(153/936 heads) and 26.3%(246/936 heads), respectivily. Agreement of reactions between IFAT and ELISA was shown 82.4% in 936 dog sera. The specificity and sensitivity of ELISA reaction were 83.5% and 76.5%, respectively. From the conclusion obtained in this study it was evaluated that IFAT and ELISA were useful as highly specific, sensitive and stable serelogical tools for the diagnosis of canine babesiosis in Korea.

• Carbon letters
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• 제6권4호
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• pp.227-233
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• 2005

Carbonization products C1, C2, C3, C4 and C5 were prepared by the carbonization of date pit in limited air, at 500, 600, 700, 800 and $1000^{\circ}C$, respectively. C1-V-600, C3-V-600, C1-V-1000 and C3-V-1000 were prepared by thermal treatment of C1 and C3 under vacuum at 600 and $1000^{\circ}C$. The textural properties were determined from nitrogen adsorption at 77 K and from carbon dioxide adsorption at 298 K. The surface pH, the FTIR spectra and the acid and base neutralization capacities of some carbons were investigated. The amounts of surface oxygen were determined by out-gassing the carbon-oxygen groups on the surface as $CO_2$ and CO. The adsorption of water vapor at 308 K on C1, C2, C3 and C4 was measured and the decomposition of $H_2O_2$ at 308 K was also investigated on C1, C2, C3, C4 and C5. The surface area and the total pore volume decreased with the rise of the carbonization temperature from 500 to $1000^{\circ}C$. The adsorption of water vapor is independent on the textural properties, while it is related to the amount of acidic carbon-oxygen groups on the surface. The catalytic activity of $H_2O_2$ decomposition does not depend on the textural properties, but directly related to the amount of basic carbon-oxygen complexes out-gassed as CO, at high temperatures.

• 한국식품저장유통학회지
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• 제6권2호
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• pp.137-142
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• 1999

마늘의 저장조건을 저온(3$\pm$1$^{\circ}C$, 80$\pm$5% RH, LT), 움(9$\pm$6$^{\circ}C$, 80$\pm$5% RH, PT) 및 상온(14$\pm$11$^{\circ}C$, 67$\pm$5% RH, AT)으로 구분하여 9개월간 물리화학적 품질 변화를 조사하였다. 저장 중 마늘의 발아율은 저온조건에서는 상대적으로 낮게 나타났으나 움식 및 상온저장에서는 높게 나타나 이상의 조건에서는 발아억제 방안이 요구되었다. 마늘의 부패율은 저장 7개월 째인 이듬해 3월까지는 낮았으나 그 이후에는 저장조건에 상관없이 급격히 부패되었다. 마늘의 중량은 저장기간이 경과됨에 따라 저장 온ㆍ습도의 변화에 따라 감소하였으며, 특히 외부발아와 더불어 줄어드는 경향이 심하였다. 저온저장에서 수분함량은 이듬해 5월까지 큰 변화가 없었으나 움식 및 상온저장에서는 이듬해 1월부터 상당히 감소되었다. 전당의 함량은 완만하게 감소되는 편이었으나 환원당 함량은 이듬해 3월부터 외부발아 현상과 비례하여 급격히 증가되었다. 마늘의 vitamin C 함량은 저장 중 큰 변화가 없었으나 이듬해 봄부터 발아현상과 더불어 증가되었다. 이상의 결과에서 볼 때 마늘의 저장은 이듬 3월경이 물리화학적 변화가 가장 왕성한 한계 시점이라고 생각되며, 이 한계점을 극복하기 위한 저장조건의 적용이 요구되고 있다.

• Journal of Periodontal and Implant Science
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• 제50권1호
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• pp.56-66
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• 2020

Purpose: A stability-measuring device that utilizes damping capacity analysis (DCA) has recently been introduced in the field of dental implantology. This study aimed to evaluate the sensitivity and reliability of this device by measuring the implant stability of ex vivo samples in comparison with a resonance frequency analysis (RFA) device. Methods: Six implant beds were prepared in porcine ribs using 3 different drilling protocols to simulate various implant stability conditions. Thirty-six pork ribs and 216 bone-level implants measuring 10 mm in height were used. The implant beds were prepared using 1 of the following 3 drilling protocols: 10-mm drilling depth with a 3.5-mm-diameter twist drill, 5-mm drilling depth with a 4.0-mm-diameter twist drill, and 10-mm drilling depth with a 4.0-mm-diameter twist drill. The first 108 implants were external-connection implants 4.0 mm in diameter, while the other 108 implants were internal-connection implants 4.3 mm in diameter. The peak insertion torque (PIT) during implant placement, the stability values obtained with DCA and RFA devices after implant placement, and the peak removal torque (PRT) during implant removal were measured. Results: The intraclass correlation coefficients (ICCs) of the implant stability quotient (ISQ) results obtained using the RFA device at the medial, distal, ventral, and dorsal points were 0.997, 0.994, 0.994, and 0.998, respectively. The ICCs of the implant stability test (IST) results obtained using the DCA device at the corresponding locations were 0.972, 0.975, 0.974, and 0.976, respectively. Logarithmic relationships between PIT and IST, PIT and ISQ, PRT and IST, and PRT and ISQ were observed. The mean absolute difference between the ISQ and IST values on a Bland-Altman plot was -6.76 (-25.05 to 11.53, P<0.05). Conclusions: Within the limits of ex vivo studies, measurements made using the RFA and DCA devices were found to be correlated under a variety of stability conditions.

• Biomolecules & Therapeutics
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• 제28권1호
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• pp.83-91
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• 2020

Tryptamines are monoamine alkaloids with hallucinogenic properties and are widely abused worldwide. To hasten the regulations of novel substances and predict their abuse potential, we designed and synthesized four novel synthetic tryptamine analogs: Pyrrolidino tryptamine hydrochloride (PYT HCl), Piperidino tryptamine hydrochloride (PIT HCl), N,N-dibutyl tryptamine hydrochloride (DBT HCl), and 2-Methyl tryptamine hydrochloride (2-MT HCl). Then, we evaluated their rewarding and reinforcing effects using the conditioned place preference (CPP) and self-administration (SA) paradigms. We conducted an open field test (OFT) to determine the effects of the novel compounds on locomotor activity. A head-twitch response (HTR) was also performed to characterize their hallucinogenic properties. Lastly, we examined the effects of the compounds on 5-HTR1a and 5-HTR2a in the prefrontal cortex using a quantitative real-time polymerase chain reaction (qRT-PCR) assay. None of the compounds induced CPP in mice or initiated SA in rats. PYT HCl and PIT HCl reduced the locomotor activity and elevated the 5-HTR1a mRNA levels in mice. Acute and repeated treatment with the novel tryptamines elicited HTR in mice. Furthermore, a drug challenge involving a 7-day abstinence from drug use produced higher HTR than acute and repeated treatments. Both the acute treatment and drug challenge increased the 5-HTR2a mRNA levels. Ketanserin blocked the induced HTR. Taken together, the findings suggest that PYT HCl, PIT HCl, DBT HCl, and 2-MT HCl produce hallucinogenic effects via 5-HTR2a stimulation, but may have low abuse potential.