Electrooptic 물질 KTiOPO₄(KTP)의 핵자기공명 연구

한정관(J. K. Han),오동근(D. K. Oh),이창훈(C. H. Lee),이철의(Cheol Eui Lee),김정남(J. N. Kim),김성철(S. C. Kim) 한국자기학회 1996 韓國磁氣學會誌 Vol.6 No.5

We have carried out a ³¹P nuclear magnetic resonance (NMR) study on the electrooptic material KTiOPO₄ (KTP). From the spin-lattice relaxation time (T₁) measurements at 17.9 ㎒ in the temperature range 77-390 K, two phase transitions associated with the change of the dominant charge carriers were observed and the activation energies were obtained in each phase.

특별강연 및 학술연구 발표요지 : 가능성 미생물 Sclerotinia sp., Isolate BWC98-105를 이용한 클로버의 생물적 방제

홍연규 ( Y. K. Hong ),김정남 ( J. N. Kim ),전민구 ( M. G. Jeon ),송석보 ( S. B. Song ),박성태 ( S. T. Park ),송경식 ( K. S. Song ),황재복 한국잡초학회 2006 한국잡초학회 별책(학술대회 초록집) Vol.26 No.2

TSSG 법으로 육성한 LiB₃O5 단결정의 제2조화파 발생 특성

권택용(T. Y. Kwon),오학태(H. T. Oh),주정진(J. J. Ju),백현호(H. H. Baek),김정남(J. N. Kim),윤수인(S. I. Yun) 한국광학회 1994 한국광학회지 Vol.5 No.1

이 연구에서는 TSSG 법으로 육성한 LiB₃O_5(LBO) 단결정의 1064 ㎚ 광에 대한 type Ⅰ 및 type Ⅱ 제 2 조화파 발생(SHG) 특성을 조사하였다. Type Ⅰ SHG의 위상정합각은 θm=90°, φm=11.6°였고 angular acceptance bandwidth는 각각 δθintL½=3.3°-㎝½, θφintL=0.27° -㎝로 측정되었다. Type Ⅱ SHG의 위상정합각은 θm=20°, φm=90° 였고 angular acceptance bandwidth는 각각 δθintL=0.65° -㎝, δφintL½=35° -㎝½로 측정되었다. Type Ⅰ NCPM SHG 온도는 149℃였고 temperature bandwidth ΔTL은 4.8℃ -㎝였다. Nd:YAG 레이저의 peak power 가 171 MW/㎠일때 두께가 2.6 ㎜인 LBO 결정의 SHG 변환효율은 약 1.8%였고, 이차 비선형 계수 d₃₂는 약 0.74±0.05 pm/V로 측정되었다. The characteristics of the type Ⅰ and type Ⅱ SHG in LiB₃O_5 crystals grown by TSSG method have been investigated using 1064 ㎚ beam from a Q-switched Nd:YAG laser. The measured phase matching angles and angular acceptance bandwidths were θm=90°. φm=11.6°, δθintL½=3.3°-㎝½. δφintL=0.27°-㎝ for type Ⅰ SHG and θm=20°, φm=90°, δθintL=0.65°-㎝, δφintL½=3.5°-㎝½ for type Ⅱ SHG, respectively. The type Ⅰ NCPM temperature of 1064 ㎚ beam was found to be 149℃ with the temperature bandwidth ΔTL of 4.8℃ -㎝. An energy conversion efficiency of about 1.8% with 2.6 ㎜ thick LBO crystal at an incident power of 171 MW/㎠ was demonstrated. The measured d₃₂ was 0.74±0.05 pm/V.

기주특이적 생물제제를 이용한 잡초방제 기술

홍연규(Yeon Kyu Hong),이봉춘(B. C. Lee),송석보(S. B. Song),박성태(S. T. Park),김정남(J. N. Kim),전민구(M. K. Koo),김인섭(I. S. Kim) 한국잔디학회 2006 한국잔디학회 정기총회 및 학술발표회 Vol.19 No.-

The term mycoherbicide originated in the 1970's to differentiate this strategy from classical strategy of relying upon self-perpetuation introduced organisms for weed control. Interest in bioherbicides is hightened in particular by the increasing costs of chemical herbicides, lack of adequate chemical control for some weeds and the social concerns about the widespread use of pesticides. After release, a classical biocontrol agent is expected to become a permanent part of its new environment and it is vital to ensure, as far as possible, that it will do more good than harm there. This is done through risk assessment, which invariably includes host range testing. Contemporary biological control system includes the use of fungi to control weeds in agricultural ecosystems and forests. Biological control agent (BCA) of weeds that are highly virulent and specific to target weeds, and able to be produced massively by artificial culture could be applied like chemical herbicides over the weeds. The approach of mycoherbicide(BCA)is differed from the classical approach in which plant pathogens are released through natural spread. The use of pathogenic fungi as classical biological control agents for weeds began in 1971. To date, 26 species of fungi, originating from 15 different countries, have been used as classical BCA against over 26 species of weeds in seven countries. Information is presented on the performance of these pathogens in the field after release, compared with predictions made on the basis of prerelease host-range testing. The mechanisms and evolution of plant resistance are discussed in relation to risk assessment. No reports were uncovered of deliberately introduced fungi unexpectedly attacking non-target plants after release. Indeed, host-range testing results have often proved conservative, with a number of examples of pathogens attacking non-target plants in prerelease tests, but not being recovered from these species in the field. It is concluded that risk assessments based on rigorous host-range testing, combined with a good understanding of the taxonomy, biology, and ecology of the agent, the target weed, and non-target species, can ensure that the introduction of exotic pathogens is a safe and environmentally benign method of weed control. However, many pathogens have not been successfully used in practice as mycoherbicide to date despite the extensive researches and developments. Of the 80 weed control projects, 71 involved fungi, 6 involved viruses, and 3 each involved bacteria and nematodes. Charudattan added the list 153 mycoherbicide projects recently. One estimated that 30 weeds might be controlled with mycoherbicides by the year 2000, without taking into account the potential genetic engineering and other advances in biotechnology. Developed under such a definition, many mycoherbicides were considered which have shown their potentials in the laboratory or greenhouse, but most of them have been ineffective in the field. In addition, for some mycoherbicide candidates, control efficacy was not consistent from year to year or from field to field. These contradictions indicate lack of understanding of one or more important ecological factors or mechanisms contributing to the suppression of weeds by plant pathogens in the field. It is necessary to understand what are the suitable conditions of temperature and relative humidity to control the target weed with plant pathogen before applying in field. Nevertheless, under field conditions dew formation and its duration are difficult to predict. In the studies of biological control of weed with pathogens, there are some notable examples. Most weed species are hosts for many endemic pathogens, thus, a potential pathogen must be selected as a BCA. Daniel et al.suggested that these pathogens must ; (1) be able to produce abundant and durable inoculum in artificial culture, (2) be genetically stable and specific for the target weed, and (3) be able to infect and kill the

희토류 원소를 첨가한 LiNbO₃단결정의 磁氣的性質

김영제,김장환,김정남,이재현 부산대학교 1982 자연과학논문집 Vol.34 No.-

Magnetic susceptibilities of lithium niobate single crystals doped with rare earth elements(Eu, Sm and Dy) were measured by Faraday method in the range from -170℃ to 20℃. While samples LiNbO₃:Eu and LiNbO₃:Sm showed diamagnetism, samples LiNbO₃:Dy showed paramagnetism in the same range of temperature. Also we attempted to calculate dopant concentrations from the fitted data with Langevin paramagnetic formula.

Superconductivity of Y_(1.2) Ba_(0.8)CuO_(4-y)

Jang, M.S.,Y.W Park,Kim, J.W.,Kim, J.N.,Ro, J.H.,Kim, H.K. 부산대학교 기초과학연구소 1988 부산대학교 기초과학연구소 연구논문집 Vol.8 No.-

새로운 Y-Ba-Cu 산화물 세라믹의 초전도성을 연구하기 위해 전기저항, 자화율 그리고 열전력을 측정했으며, 우리의 2가지 시료에 대해 일치되는 결과를 얻었다. 90K 근방에서 초전도성 상전이가 일어났으며, 상전이 온도는 시료에 부하된 전류밀도에 대해 매우 민감했다. 그리고 열전력 측정 결과에 의하면 상전이 점 부근에서 phonon 방출의 증가를 보이므로 P-형 초전도체이다.

Gadolinium 및 Vanadium을 첨가한 LiNbO₃단결정의 자기적 성질에 관한 연구

정현선,김장환,김정남,이재현 부산대학교 1983 자연과학논문집 Vol.35 No.-

Single crystals of lithium niobate doped with gadolinium(Gd) and vanadium(V) were grown. Magnetic susceptibilities of these samples were measured by Faraday method in the temperature range from 120K to 300K. The magnetic susceptibilities of LiNbO_(3): Gd show Langevin paramagnetism. The measurements of LiNbO_(3): V show diamagnetism. Through the annealing process magnetic property of LiNbO_(3): V is changed from diamagnetism to Langevin paramagnetism.

천이원소(Cr,Fe,Ni)를 첨가한 LiNbO₃단결정의 자기적 성질

김장환,김정남,이재현,옥치일 부산대학교 물성연구소 1983 물성연구소연구논문집 Vol.2 No.-

Magnetic susceptibilities of single crystal LiNbO₃doped with transition elements (Cr, Fe and Ni) were measured by Faraday magnetometer in the range from 100k to 400k. The data of annealed crystal LibO₃:Fe are quite different from those of unannealed ones. The concentrations of impurities (Cr, Fe and Ni) in the four samples can be calculated by comparing the data with the Curie's law.

태양에너지 사용을 위한 집열계통면 개발

윤수인,노동택,노지현,김정남 부산대학교 물성연구소 1982 물성연구소연구논문집 Vol.1 No.-

The measured solar absorptance and spectral emittance of the nickel black and chrome black coatings prepared by lectroplating at various plating current densities were reported. The cyclic heating and cooling technique was mployed for the absorptance measurement of these coatings. The nickel black coating with α=0.87 and ε(100℃)=0.25 was obtained by plating at 30℃ for 5minutes with the current density of 0.1A/dm². Where as the best chrome black coating with α=0.89 and ε(100℃)=0.21 was achieved by plating at 20℃ for one minute with the current density of 100A/dm². Accelerated humidiry and themal durabilitys test result on these coatings was also reported.

LiNbO₃ 단결정 표면의 Chemical Etching에 관한 연구

진광수,김정남,이재현 부산대학교 물성연구소 1984 물성연구소연구논문집 Vol.3 No.-

LiNbO₃단결정의 X, Y, Z _ 면상에 chemical etching을 하여 여러가지 etch pit와 hillock pattern을 얻었다. 본 실험에서 사용한 etchant는 이미 알려진 HF, HNO₃를 모체로 하여 CH₃COOH, KBr, Li₂CO₃, Nb₂O_(5) 그리고 H₂SO_(6)중에서 한가지 또는 두가지를 첨가한 것을 사용함으로써 선명한 etch pattern을 얻었다. 그리고 이결정의 각 면에 생긴 etch pattern들을 좌표측에 따라 입체적으로 그려서 정리하고, ion배열을 조사하였다. The etch pits and hillocks are produced on the different crystallographic planes in LiNbO₃single crystal by the chemical etching. Various new compositions of CH₃COOH, KBr, Li₂CO₃, Nb₂O_(5) and H₂SO₄are tried to find the reliable etchant for X, Y, and Z-planes of LiNbO₃single crystals. Furthermore the relationship of ethcing morphology with the ionic arrangement on each crystallographic plane are discussed.