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고온 초전도체 Y₁Ba₂Cu₃O_7-δ(CdO)_x의 핵사중극 상호작용 연구
전인,김복수,노태호,김영훈,서용문,송승기,박영민 명지대학교 자연과학연구소 2000 자연과학논문집 Vol.19 No.-
CdO가 첨가된 고온 초전도체 Y1Ba2CU3O7-δ(CdO)x(x=0.00,0.09,0.22,0.34,0.42,0.49)를 고상 반응법으로 제작하여 상온에서 Cu 핵사중극 공명 실험을 하였다. 구리-산소 평면에 있는 63Cu(2)의 핵사중극 공명 진동수는 31.13∼31.39 MHz이고, 65Cu(2)의 공명 진동수는 28.82∼29.06 MHz이었다. 이러한 공명 진동수는 χ가 증가할수록 높은 진동수 방향으로 이동하였다. 63Cu(2)과 65Cu(2)의 NQR 공명 진동수의 비는 모든 시료가 1.08로 63Cu과 65Cu의 핵 사중극 모멘트의 비와 같았다. 구리-산소 사슬에 있는 63Cu(1)의 공명 진동수는 22.15~22.36 MHz에서 관측되었는데, χ에 따른 공명 진동수의 이동 경향은 63Cu(2)과 65Cu(2)의 경우와 비슷하였다. 선폭은 63Cu(2)과 65Cu(2)그리고 63Cu(1)의 경우 모두 약 200∼300 kHz고, 전반적으로 χ가 증가할 수록 감소하였다. 스핀-에코 방법으로 구한 스핀-스핀 이완 시간 T2는 χ가 증가함에 따라 약간씩 증가하였다. We have studied Cu-NQR in CdO-mixed high-Tc superconductor Y1Ba2Cu3O7-δ(CdO)x(x=0.00, 0.09, 0.22, 0.34, 0.42, 0.49) at room temperature prepared by solid state reaction method. In the Cu-O plane, 63Cu(2)-NQR frequencies were measured to be in the range of 31.13-31.39 MHz and those of 65Cu(2) were in the range of 28.82-29.06 MHz. The position of spectrum-peaks shifted to the higher frequency with increasing χ. The ratio of 63Cu(2) and 65Cu(2)-NQR frequencies have the value of 1.08 which is equal to the ratio of 63Cu(2) and 65Cu(2) nuclear quadrupole moment for all samples. The resonance frequencies of 63Cu(1) in the Cu-O chain have been observed in the range of 22.15-22.36 MHz and the tendency of resonance frequency behaviour with χ were nearly the same for both 63Cu(2) and 65Cu(2). The line-widths of 63Cu(2), 65Cu(2) and 63Cu(1) were observed to the value of 200∼300 kHz and they decreased with increasing χ. The spin-spin relaxation time T2 obtained by spin-echo method increased slightly with increasing χ.
산전 태아사망 환자에서의 Mycoplasma hominis와 Viridans streptococcus감염 1예
김윤숙,문성택,전섭,김종수,최승도,선우재근,배동한 순천향의학연구소 2007 Journal of Soonchunhyang Medical Science Vol.13 No.1
Mycoplasma hominis was isolated from a Bartholin's gland abscess 70 years ago, and ureaplasmas were isolated from the genital tract about 20 years later. Subsequently, reports incriminating mycoplasmas in the known adverse outcomes of pregnancy have been reported. Without doubt these genital mycoplasmas are able to invoke an inflammatory response and take part in the cascade of events that culminate in preterm birth. Amniotic fluid infection results in considerable pregnancy wastage in the pregnancy. In these cases Gram-positive organisms, especially group B streptococcus and Streptococcus viridans were the most common pathogens isolated. In our case, the patient has fever and vaginal discharge at 14+4 weeks gestation and two days after intrauterine fetal death was seen. The vaginal culture and sensitivity shown Mycoplasma hominis and Vihdans streptococcus. We experienced a case of Mycoplasma hominis and Viridans streptococcus infection in a patient with intrautehne fetal death and report with a brief review of literatures.
77K와 상온에서 CO(NH₂)₂의 ¹⁴N Pulsed NQR 연구
강재필,박영민,전인,김성재,최숙자,박현진,송승기,서용문 명지대학교 자연과학연구소 1996 자연과학논문집 Vol.13 No.-
77K와 상온에서 CO(NH₂)₂분말 시료의 ??N Pulsed NQR실험을 하여 위와 아래 공명 진동수, 핵 사중극 결합상수, 비대칭 인자, 스핀-스핀 완화시간, 결정 격자 진동에서의 평균 비틀림 진동수, 진동자의 관성 모먼트 등을 구하였다. 공명 진동수의 온도 의존성은 전형적인 Bayer이론의 격자 진동에 의한 주파수 변화를 보였다. Bayer-Kushida이론의 고온근사식을 실험값에 적용하여 OK에서 공명 진동수 ν??와 ν??를 구했으며, 77K와 상온에서의 스핀-스핀 완화시간 T₂를 관측했다. 상온에서 T₂의 감소는 결정 내의 reorientation motion과 관련이 있을 것으로 보인다. Upper and lower resonance frequencies, nuclear quadrupole coupling constants, asymmetry parameters, spin-spin relaxation time, average torsional frequency in the crystal lattice motion and moment of inertia in the oscillator are found for CO(NH₂)₂powder sample by using ??N Pulsed NQR(Nuclear Quadrupole Resonance) technique at 77K and room temperature. Temperature dependence of resonance frequencies showed frequency variation in agreement with the typical Bayer's theory in lattice motion. Resonance frequencies ν?? and ν?? at OK were obtained by fitting the high temperature approximation of Bayer-Kushida theory to the experimental data and spin-spin relaxation time (T₂) was observed at 77K and room temperature. Decrease of T₂at room temperature was explained by the effect of reorientational motion in the crystal lattice.
Seung Mun Jeon,Gun Hee Jang,Won Seo Lee IEEE 2014 IEEE transactions on magnetics Vol.50 No.11
<P>We propose a novel double helical magnetic micromachine (DHMM) to achieve drug-enhanced unclogging abilities for occlusive vascular diseases (OVDs) in human blood vessels. The proposed DHMM can generate navigating and mechanical drilling motions actuated by an external rotating magnetic field (ERMF). It can also deliver a clot-busting drug to a target point (clogged area) and can precisely release the drug toward the clogged area. We derive rotational dynamic constraint equations for selective manipulation of the navigating, drug releasing, and mechanical drilling motions of the DHMM by controlling the ERMF. We then prototype the DHMM and demonstrate these motions to show the validity of the proposed DHMM and manipulation methods.</P>