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제일원리계산방법에 의한 결정 구조에 따른 덩치 망간의 전자 구조와 자성 변화 연구 : 면심입방과체심입방 구조의 망간 fcc and bcc Mn
노태환,홍순철 울산대학교 2002 자연과학논문집 Vol.11 No.2
덩치 망간의 평형상태에서의 결정구조와 자성 구조는 아주 복잡한 것으로 알려져 있다. 본 연구에서는 자성 연구에서 가장 적합한 방법으로 알려져 있는 Full-potential Linearized Augmented Plane Wave(FLAPW) 방법을 사용하여 격자상수의 함수로 면심입방 Mn과 체심입방 Mn의 계산 가능한 자성 상태(상자성, 강자성, 반강자성 상태)의 총에너지를 계산하여 결정구조에 따른 Mn의 자성 변화를 연구하였다. 계산 결과, 면심입방 Mn은 반강자성 상태가 안정하고 체심입방 Mn은 강자성상태가 안정한 것으로 밝혀졌다. 면심입방 Mn과 체심입방 Mn의 평형상태의 격자상수는 각각 6.750, 5.314 a.u. 이었고 자기모멘트는 1.15 μ_B과 0.85 μ_B인 것으로 계산되었다. 면심입방의 경우는 강자성 상태가, 체심입방의 경우는 반강자성 상태가 전혀 안정되지 못하는 것으로 나타났다. Manganese is known to have a very complicated crystal structure due to its complex magnetism. In this study we investigated the magnetism of fee and bcc Mn as functions of lattice constants, using Full-potential Linearized Augmented Plane Wave(FLAPW) method and assuming para-, ferro-, and antifcrro-magnetic states. The anti ferromagnetic and ferromagnetic states were calculated to be energetically stable for fee Mn and bcc Mn, respectively. The lattice constants of fee and bcc Mn at equilibrium are 6.750 and 5.314 a.u. and the magnetic moments are 1.15 and 0.85 μ_B, respectively. The ferro- and antiferro-magnetic states are so unstable (not even metastable) that the states were converged to the other magnetic states in self-consistent calculations.
Irrigation with Microbial-Contaminated Water and Risk of Crop Contamination
최연식,송인홍,권순국,Choi, C. Yeon-Sik,Song, In-Hong,Kwun, Soon-Kuk The Korean Society of Agricultural Engineers 2007 한국농공학회논문집 Vol.49 No.2
The aim of this study was to compare crop contamination between two irrigation methods using microbial-contaminated water. The effect of relative humidity on microbial survival of the three indicator microorganisms was also investigated. Escherichia coli ATCC 25922, Clostridium perfringens ATCC 3624, and coliphage PRD1 were applied to irrigation water to grow cantaloupe, lettuce, and bell pepper. Half of the sixteen plots were subsurface drip irrigated (SDI) and the other half were furrow irrigated (FI). Two relative humidity levels were controlled at 15-65 % and 55-80 % for the dry and humid condition experiments, respectively. Samples of produce, surface soil, and subsurface soil at a depth of 10 cm were collected over a two-week period following the application of the study microorganisms. Overall, greater contamination of both produce and soil occurred in the FI plots. For the SDI plots, preferential water paths and resulting water appearance on the seed beds seemed to be responsible for produce contamination. Relative humidity levels did not appear to affect microbial survival in soil. PRD 1 showed lower inactivation rates than 5. coli in both dry and humid conditions. C. perfringens did not experience significant inactivation over the experimental period, suggesting this microorganism can be an effective indicator of fecal contamination.
FIRST PRINCIPLE CALCULATIONS OF MCD SPECTRA FOR SANDWICHED Co(110) SYSTEMS
Soon C. Hong,Jae Il Lee,R. Wu,A.J. Freeman 한국자기학회 1995 韓國磁氣學會誌 Vol.5 No.5
X-ray magnetic-circular-dichroism (MCD) spectra, orbital (<Lz>) and spin magnetic moments (<Sz>) for Co(110) monolayers a free standing mode or sandwiched between Pd (Pd/1Co/Pd) and Cu layers (Cu/1Co/Cu) are calculated using the thin film full potential linearized augmented plane wave energy band method. In contrast to the double peak structure predicted for the Co(0001) surface, only a minor side peak is found in the MCD spectra for Cu/Co/Cu, while MCD spectra for the other systems show a single peak structure. The MCD sum rules originally derived from a single ion model are found in the band approach to be valid for the systems investigated. However, for the spin sum rule, the magnetic dipole term (<Tz>) is not negligible and needs to be included.
W(110)위에 성장한 Fe 웃층의 전자 및 자기적 성질
홍순철(Soon C. Hong),이재일(Jae Il Lee),A. J. Freeman(A. J. Freeman) 한국자기학회 1991 韓國磁氣學會誌 Vol.1 No.2
The electronic and magnetic structure of Fe overlayers on W(110) is determined by means of the all-electron local spin density full potential linearized augmented plane wave (FLAPW) method with a single slab approach. Charge and spin densities, magnetic moments, contact hyperfine fields, and layer projected density of states (LDOS) are presented. For bilayer Fe coverage, we find magnetic moments to be 2.90 and 2.30 μ_B for the surface and subsurface Fe layers, respectively, corresponding to a 18% enhancement of the total magnetization compared with the calculated bulk value (2.22μ_B);For monolayer coverage the moment is 2.56μ_B which is enhanced by 16% compared to bulk. Unusual changes in the magnetic hyperfine interaction are found in going from a monolayer to a bilayer coverage. Comparison of the results to the theoretical ones of the clean Fe(110) to discuss the hybridization and the negative pressure effects. We discuss our results by comparing them to experimental results.
Sensitivities of Entomopathogenic Fungus Aschersonia aleyrodis to Bordeaux Mixtures and Lime Sulfur
Sang Soo Oh,Jeong Heub Song,Soon Yeong Hong,Shin Chan Lee,Seong Keun Kang 한국응용곤충학회 2011 한국응용곤충학회 학술대회논문집 Vol.2011 No.10
Aschersonia aleyrodis was well-known to be a biological control agent for citrus whitefly, Dialeurodes citri. This entomopathogenic fungus is naturally occurred in organic farming citrus orchards in Jeju. Both lime-sulfur and Bordeaux mixtures are extensively used today to control citrus diseases like citrus melanose and citrus scab, especially in organic farming pest management program. The high concentrated lime-sulfur is also used for pest control such as pink citrus rust mite and scale insects. This study was focused to test the conidial germination and sporulation of Aschersonia aleyrodis on potato dextrose agar (PDA) medium containing different concentrations of two fungicides. The conidia of Aschersonia aleyrodis grown on PDA mixed with commercial bordeaux mixtures, CM150-505, at dilution rate 1:200 (water : bordeaux mixture) were well-germinated but not sporulated at all. On the other hand, Aschersonia aleyrodis did not sporulate and germinate on lime sulfur treated PDA medium even at extremely low dilution rate 1:2,048,000 (water : lime sulfur). However, when the mycelial cells grown at 25o C for at least 7 days at soluble starch-tryptone medium were added to PDA, they were well-sporulated even at high dilution rate 1:100 (water : lime sulfur). This result suggested that the spore mixtures of Aschersonia aleyrodis should be applied to field quite long after lime-sulfur spray.
Reduction of Plasma Nitrogen Oxides by Flames of Hydrocarbon Fuel
엄환섭,Soon C. Cho,Il G. Park,Min S. Hong 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.6
Nitrogen oxides generated in a microwave plasma torch are destroyed by a flame of hydrocarbon fuel. A high-temperature plasma torch in the microwave plasma burner produces a high level of nitrogen oxides, which disintegrate in the fuel-burning flame exponentially in terms of the methane flow rate. However, the flame from the fuel combustion generates its own nitrogen oxides, although their concentration levels are considerably lower compared to those from the plasma torch. Theoretical results from an analytical model based on simple gas kinetic data agree reasonably well with experimental data.
( Jae Min Lee ),( Hong Sik Lee ),( Jong Jin Hyun ),( Jung Min Lee ),( In Kyung Yoo ),( Seung Han Kim ),( Hyuk Soon Choi ),( Eun Sun Kim ),( Bora Keum ),( Yeon Seok Seo ),( Yoon Tae Jeen ),( Hoon Jai C 대한간학회 2018 Gut and Liver Vol.12 No.3
Background/Aims: Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is useful for obtaining pancreatic mass samples. The combination of modified techniques (i.e., slow-pull technique and fanning technique) may improve the quality of the sample obtained by EUS-FNA. We investigated the effectiveness of a combined slow-pull fanning technique in EUS-FNA for pancreatic mass. Methods: This prospective comparative study investigated EUS-FNA performed for pancreatic solid masses between August 2015 and July 2016. Pairwise specimens were alternately obtained using the following two techniques for targeted pancreatic lesions: standard suction or slow-pull with fanning. We compared the specimen quality, blood contamination, and diagnostic accuracy of these techniques. Results: Forty-eight consecutive patients were included (29 men; mean age, 68.1±11.9 years), and 96 pancreatic mass specimens were obtained. The slow-pull with fanning technique had a significantly superior diagnostic accuracy than the suction technique (88% vs 71%, p=0.044). Furthermore, blood contamination was significantly reduced using the slow-pull with fanning technique (ratio of no or slight contamination, 77% vs 56%, p=0.041). No difference was observed in the acquisition of adequate cellularity between the groups. In the subgroup analysis, the tumor size and sampling technique were related to the EUSFNA diagnostic accuracy. Conclusions: The slow-pull with needle fanning technique showed a good diagnostic yield for EUS-FNA for pancreatic mass. This technique can be useful for performing EUS-guided sampling for diagnosing pancreatic disease. (Gut Liver 2018;12:360-366)
Antitumor activity of spinasterol isolated from Pueraria roots
Gook-Che Jeon,Myoung-Soon Park,윤도영,C hul-Ho Shin,Hong-Sig Sin,엄수종 생화학분자생물학회 2005 Experimental and molecular medicine Vol.37 No.2
We purified phytoestrogens from Pueraria root (Pueraria mirifica from Thailand and Pueraria lobata from Korea), which is used as a rejuvenat-ing folk medicine in Thailand and China. Dried, powdered plant material was extracted with 100% ethanol and further separated by concentration, filtration, and thin layer silica gel chromatogra-phy. Using the fractions obtained during separa-tion, we first investigated their cytotoxicity in se-veral cancer cel lines from various tissues. The ethanol-extracted components (PE1, PE4) had sig-nificant antiproliferative efects on breast cancer cel lines, including MCF-7, ZR-75-1, MDA-MB-231, SK-BR-3, and Hs578T. Second, we compared flavonoids, sterols, and coumarins from Pueraria root. The known compounds were not as efec-tive, and occured in a diferent polarity region on HPLC. Third, further separation resulted in the isolation of eight diferent components (Sub PE-A to -H). One of these, PE-D, affected the growth of some breast cancer cel lines (MCF-7, MDA- MB-231) in a dose- and time-dependent maner, as wel as the growth of ovarian (2774) and cervical cancer cels (HeLa). Finaly, a transfec-tion assay showed that this component had an estrogenic effect similar to 17βactivates both estrogen receptor α (ERα) and ERβ. The NMR analysis determined that spin-asterol (stigmasta-7, 22-dien-3beta-ol) is an active cytotoxic component of Pueraria root.