V₂O-B₂O₃-PbO 유리의 전자 상자성 공명연구

노태호,전인,박영민,강재필,김성재,박현진,송승기 명지대학교 자연과학연구소 1996 자연과학논문집 Vol.14 No.-

V₂O??-B₂O₃-PbO 유리의 VO??에 관한 전자 상자성 (EPR) 스펙트럼으 연구하였으며, vanadium이온의 스핀해밀토니안 상수들을 구하였다. 유리시료안의 V₂O??양을 증가시킴에 따라 g??과 g??값은 증가하였으나 A??과 A??값은 감소하였다. 이는 V₂O??수가 증가하면 동일 평면상의 vanadium과 oxygen배위간 결합의 공유성이 증가함을 의미한다. 유리내의 vanadium 4가이온은 정방형 일그러진 8면체를 한 vanadyl착물로 존재한다. Electron Paranmagnetic Resonance(EPR) SPECTRA OF (VO)?? in V₂O??-B₂O₃-PbO glasses have been studied and spin hamiltonian paramenters of vanadium ion have been calculated. It is found that the value of g??and g?? increases while the value of A?? and A?? decreases with an increase of V₂O?? content in the glass samples, showing that the covalency in the in-plane vanadium -oxygen ligand bonds increase with increasing the concentration of V₂O??. The tetravalent vanadium ions exist as vanadyl complexes with tetragonally distorted octahedral sites in the glasses.

고온 초전도체 Y Pr Zn Ba₂Cu₃O의 자기적 성질

김성재,박영민,노태호,전인,강재필,송승기 명지대학교 자연과학연구소 1995 자연과학논문집 Vol.12 No.-

전이 온도가 72K인 Y?Pr?-Zn?Ba?Cu?O?고온 초전도체에 초전도성을 약화시키는 Pr 원소와 Zn를 적절한 비율로 치환하여 자기적 특성을 연구하였다. Zn가 첨가되었을 때의 임계온도(전이온도)는 35~ 44K의 값을 나타내었다. 온도에 대한 비저항의 측정으로 구한 전기적 임계온도와 온도 대 자기 모우먼트 측정으로 구한 자기적 임계온도 값은 거의 비슷했다. 자기이력 곡선으로부터 H?(저임계자기장), H?(고임계자기장)와 반자성 정도를 구했으며, Bean의 모델을 이용하여 임계전류밀도를 구하였다.이러한 자기적 성질들은 시료에 Zn가 첨가되자 급격히 감소되었다. 임계전류밀도의 경우 x=0.0인 시료가 1.6x 10?A/㎠으로 계산되었고, Zn가 첨가된 다른 시료의 임게전류밀도는 3.5x10?~1.3x10?A/㎠범위의 값을 나타내었다. 이것은 시료내에서 Znr가 초전도성을 급격하게 감소시킴을 의미한다. We have studied magnetic property as a substitute appropriate propertation of Zn element for Pr element which reduces superconducting property in high-temperature superconductor Y?Pr??Zn?Ba?Cu?O?? of transition temperature 72K, When Zn is put into it, critical temperature showed the value of measurement at th range of 35 ~44K. The electric critical temperature determinded by the temperature dependence of resistivity had a similar data to the magnetic citical temperature determinded by the temperature dependence of at the range of 35 ~ 44K. The electric critical temperature determined by the temperature dependence of resistivity had a similar data to the magnetic critical temperature determined by the temperature vs. magnetic moment. H?(critical low mgnetic field ), H?(critical high magnetic field), diamagnetic ratio and critical current density calulated by Bean's model from the magnetic hysterisis curve. These properties were abruptly decreased with adding Zn in the samples, Especially , the critical current desity of x=0.0 sample was calculated at 1/6x 10?A/㎠.These mean that Zn in the sample decreases superconduting properties in the sample.

칼슘과 아연으로 치환된 Y0.8 Pr0.₂ Ba₂ Cu₃ O7_δ 의 전기 및 자기적 성질에 관한 연구

김성재,전인,박영민,강재필,노태호,박현진,최숙자,송승기 명지대학교 자연과학연구소 1996 자연과학논문집 Vol.14 No.-

전이온도가 72K인 고온초전도체 Y?P?B?Cu?O?에서 초전도성을 감소시키는 Pr원소자리에 Ca과 Zn를 적당히 치환시켜 자기적 성질을 연구하였다. 초전도 전이온도(Tc)는 Ca이 치환된 시료의 경우 80~85k의 범위에서 측정되었으며, Zn가 치환된 경우에는 35~49K의 값을 보였다. 비저항의 온도 변화로부터 결정된 전기적 전이온도는 온도에 대한 자기모우먼트으 변화에서 구한 자기적 전이온도와 비슷한 값을 보였다. 자기이력곡선으로부터 Bean의 모델을 이용하여 Hcl(저임계자기장), Hc?(고임계자기장), 반자성정도, 임계전류밀도를 측정하였다. 이러한 성질들은 시료 내에 Ca의 치환량이 많아질수록 증가하였으며, Zn가 많아질수록 급격히 감소하였다. 특히 임계전류밀도는 x=0.0인 시료는 1.60x10?A/㎠이었으며 Ca이 치환된 시료는 1.30~1.98x10? A/㎠, Zn가 첨가된 시료는 3.5x10?~1.3x10?A/㎠의 값으로 계산되었다. 이것은 시료 내에서 Ca은 초전도성을 증가시키고, Zn는 초전도성을 감소시키는 것을 의미한다. We have studied magnetic properties as a appropriate substitute of Ca and Zn element for Prelement which reduces superconducting properties in the high-temperature superconductor Y?Pr?Ba?Cu?O? of transition temperature 72K. When Ca is put into, the critical temperature(Tc)showed the value of measurement at the range of 80~85K while for Zn the Tc had the range of 35~49K. The electric critical temperature determined by the temperature dependence of resistivity had a similar data to the magnetic field), Hc?(high critical magnetic field), diamagnetic ratio and critical current density have observed by Bean's model from the magnetic hysterisis curve. These properties were increased with adding Ca and abruptly decreased with adding Zn in the samples. Especially, the critical current density of x=0.0 sample was calculated at 1.60x10?A/㎠ and those of the other Ca-added samples at the range of 1.30~1.98xA/㎠and those of Zn-added samples at the range of 3.50x10?~1.30x10?A/㎠. These mean that Ca increases supercondecting properties in the sample and Zn element decreases them.

사람 뇌척수액중 Transthyretin의 항산화작용

양성렬,최기오,박종근,류문희,홍석노,김수한,안봉환,이제혁,이민화 대한신경외과학회 1994 Journal of Korean neurosurgical society Vol.23 No.4

Protective effects of human cerebrospinal fluid antioxidants against enzyme inactivation caused by metal-catalyzed oxidation systems were investigated. When purified glutamine synthetase(GS) was incubated with human cerebrospinal fluid(CSF), the enzyme was progressively inactivated. Catalase and EDTA could inhibit the enzyme inactivation by 50-80%. Small-molecular(Mr< -10,000) fraction of CSF inactivated the exogenous GS, but large-molecular(Mr> -10,000) fraction did not. The GS inactivation by the small-molecular fraction was also markedly inhibited by catalase and EDTA. These results suggested that metal-catalyzed oxidation is involved in the GS inactivation by the small-molecular fraction of CSF. Dithiothreitol(DTT) was shown to inhibit almost completely the oxidative inactivation of GS by CSF. However, DTT inhibited only partially the oxidative inactivation of GS caused by small-molecular fraction of CSF. When large-molecular fraction of CSF was separated by anion-exchange HPLC chromatogrpahy, there was a peak of antioxidant activity inhibiting the small-molecular fraction-induced GS inactivation in the presence of DTT. The antioxidant activity was neutralized by monoclonal antibodies to transthyretin. Purified transthyretin was found to efficiently inhibit ascorbate/Cu^(2+)-induced GS inactivation in the presence of DTT. Uric acid and glucose did not show any protective effect on the GS inactivation in the same condition. The above results suggest that metal-catalyzed oxidation occurs normally in human CSF, and that transthyretin may play an important role as a CSF antioxidant in protecting proteins from metal-catalyzed oxidation.

Zn를 첨가한 고온초전도체 Y Pr Ba₂Cu₃O 의 Raman 분석

강재필,김성재,박현진,노태호,송승기,박영민,전인 明知大學校 自然科學硏究所 1997 자연과학논문집 Vol.15 No.-

고온초전도제 Y Pr Ba₂Cu₃O 에 Zn를 첨가(x=0.00, 0.05, 0.10, 0.15, 0.20)하여 전이온도 측정, X-ray회절 실험과 Raman 실험을 하였다. Raman 측정결과 다섯 개의 시료가 일반적인 YBCO 초천도체의 Raman 스펙트럼에서 존재하는 다섯 개의 대칭활성모드(115cm¹,150cm¹.340cm¹,440cm¹,504cm¹)가 관측되었다. 이것은 Cu 와 관련된 대칭활성모드의 주파수가 모두 저주파 변위를 나타내어 Zn가 Cu(1)과 Cu(2)에 치환되었음을 의미한다. 저주파 변위 정도는 Zn에 거의 무관했으나, Raman 스펙트럼의 각 피이크의 선폭은 치환된 Zn에 의해 증가했다. 이 결과는 Zn가 Cu자리에 어느 한계 이상은 치환되지 못하고 시료 내에서 불순물상을 형성함을 나타내는 것이다. We measured transition temperature, X-ray diffraction pattern and Raman spectra of Zn added(x=0.00, 0.05, 0.10, 0.15, 0.20) high-T superconductor Y Pr Ba₂Cu₃O All samples have been observed five symmetric activity modes(115cm,150cm¹.340cm¹,440cm¹,504cm¹)which exist in Raman spectrum of general YBCO superconductor. This means Zn is substituted for Cu(1) and Cu(2) due to the fact that symmetric activity mode frequency related with Cu shows low-frequency shift. The degree of low-frequency shift was nearly independent on Zn but line width of Raman spectra peaks were increased by the substituted Zn. This results shows that Zn does not be substituted for Cu-site more than limit value and formes impurity phase in the sample.

용매의 선택에 따른 전도성 Polyaniline의 자기적 성질변화

오응주,서정선,노태호,류광선,정상국,송승기 명지대학교 자연과학연구소 1994 자연과학논문집 Vol.11 No.-

Polyaniline(emeraldine base:EB)를 pH에 따라 HCI로 1차 doping을 한후ESR을 사용하여 자기적 성질을 조사했다.또한 emeraldine base를 camphorsulfonic acid(HCSA), dodecylbenzene sulfonic acid(HDBSA)등의 산으로 1차 doping 시키고 이것을 m-cresol, acetic acid, 및 formic acid에 녹여 2차 doping을 한 후 SQUID 를 이용하여 자기적 성질을 측정하였다. Doping에 사용된 HCI용액의pH가 감소함에 따라 ESR 신호의 강도가 증가하였으며, 이로부터 doping에 따라 상자성을 나타나게 하는 화학종이 가타다는 것을아타내고 있다.m-cresol내에서 HCSA 및 HDBSA로 각각 doping된 EB-CSA/m-cresol 과 EB-DBSA/m-cresol 시료 무두 상자성을 나타내었고, 온도가 증가함에 따라 자하율값이 감소하는 경향을 나타내었다.χ?값은 2.18x10?과 7.87x10?emu/mol2-rings unit 보이며 두 스핀에 대한 Fermi 에너지 level(E?)에서의 상태밀도를 나타내는 N(E?)는 0.67과 0.24 상태(eV/2-rings unit?)로 나타났다.Camphorsulfonic ascid(HCSA)로 doping 된 EB를 m-cresol, acetic acid 및 chloroform 등 다른 용매에서 처리시 관찰된 자화율의 변화를 온도에 의존하지 않는 χ?값과 온도에 의존하는 χ? 값으로 구분하여 curie spin의 온도의존성을 규명하였다. Dependency of magnetic properties of polyaniline(emeraldine base:EB)on the pH of HCI used in doping was inverstigated by electron spin resonance spectroscopy. Emeraldine base doped with functionalized acid (primary dopant) such as camphorsulfonic acid (HCSA), dodecylbenzene sulfonic acid(HDBSA) was processed in various solvents (m-cresol, acetic acid, formic acid etc.)into homogeneous solution and free standing film and its magnetic properties were measured by SQUID. The intensity of ESR signal was increased with decrese in pH of HCL solution and paramagnetic behavior of doped polyaniline due to the formation of polaron upon doping could be confoirmed from these results. The same g value of 2.004±0.001 measured for all of the samples means that the chemical species which show paramagnetism are sasme. Polyanilines doped with HCSA and HDBSA in m-cresol showed paramagnetism and decrease in susceptibility with increase in temperature. χ? value was appered 2.18x10? and 7.87x10? emu/mol2-rings unit and N(E?) which is density of states at Fermi energy level for two spins was 0.67 and 0.24 state eV? 2rings unit? respectively. The changes in susceptibility of polyanilines doped with HCSA in m-cresol, acetic acid, formic acid etc. were divided into temperature independent χ? term and temperature dependent χ? term and temperature dependency of curie spin concentration was examined.

A Structure of Heterogeneous Request Handing Agent for ATM Switch Management Network

Sung Kee Noh 대한전자공학회 1997 ITC-CSCC :International Technical Conference on Ci Vol.- No.-

An Architecture of Agent System over ATM Network

Sung Kee Noh 한국통신학회 1997 Asia-Pacific Conference on Communications Vol.- No.-

P059 : CyPPA inhibits melanogenesis through activation of the ERK signaling pathway

( Sang Hyung Lee ),( Tai Kyung Noh ),( Sung Eun Chang ),( Mi Woo Lee ),( Jee Ho Choi ),( Kee Chan Moon ),( Hong Il Cho ),( Seung Hyun Bang ) 대한피부과학회 2014 대한피부과학회 학술발표대회집 Vol.66 No.2

Background: CyPPA is known as a positive modulator of SK2 and 3, which is found in HTS (high throughput screening for melanogenesis inhibitors). However, the effects of CyPPA on melanogenesis are not well known. Objectives: we evaluated CyPPA and impact on melanogenesis-related ERK signaling pathways. Methods: Mel-ab mouse melanocyte cells and human melanocytes were used to examine the effects of CyPPA on melanogenesis. To ascertain the CyPPA effect, microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase related protein (TRP) 1 and TRP 2 were examined by Western blotting and RT-PCR. We also investigated the phosphorylation of ERK, which is related to melanin regulation. Results: These results showed that melanin content and tyrosinase activity were significantly reduced in both cells without cytotoxicity. However, as it does not affect the activity of mushroom tyrosinase, CyPPA does not seem to be a direct inhibitor of tyrosinase. The level of MITF, Tyrosinase, TRP1 and TRP 2 expression were decreased. CyPPA induced phosphorylation of ERK and specific ERK phosphorylation inhibitor, PD98059, partially recovered the CyPPA-mediated inhibition of proteins associated with melanin synthesis such as MITF, TRP1, and TRP2. Conclusion: These results suggest that CyPPA inhibits melanogenesis through activation of the ERK signaling pathway.

Determination of Pyraclostrobin and Trifloxystrobin Residues in Red Pepper Powder Processed from Raw Red Pepper

Noh, Hyun Ho,Kwon, Hyeyoung,Lee, Hyo Sub,Ro, Jin-ho,Kyung, Kee Sung,Moon, Byeong-chul Springer-Verlag 2019 Food analytical methods Vol.12 No.1