$^{13}C$ Nuclear Magnetic Resonance Study of Graphite Intercalated Superconductor $CaC_6$ Crystals in the Normal State

김성훈,강기혁,민병진,이무희,김준성,Kim, Sung-Hoon,Kang, Ki-Hyeok,Mean, B.J.,Ndiaye, B.,Lee, Moo-Hee,Kim, Jun-Sung The Korean Superconductivity Society 2010 Progress in superconductivity Vol.12 No.1

$^{13}C$ NMR (nuclear magnetic resonance) measurements have been performed to investigate the local electronic structure of a superconducting graphite intercalation compound $CaC_6$ ($T_c$ = 11.4 K). A large number of single crystals were stacked and sealed in a quartz tube for naturally abundant $^{13}C$ NMR. The spectrum, Knight shift, linewidth, and spin-lattice relaxation time $T_1$ were measured in the normal state as a function of temperature down to 80 K at 8.0 T perpendicular to the c-axis. The $^{13}C$ NMR spectrum shows a single narrow peak with a very small Knight shift. The Knight shift and the linewidth of the $^{13}C$ NMR are temperature-independent around, respectively, +0.012% and 1.2 kHz. The spin-lattice relaxation rate, $1/T_1$, is proportional to temperature confirming a Korringa behavior as for non-magnetic metals. The Korringa product is measured to be $T_1T\;=\;210\;s{\cdot}K$. From this value, the Korringa ratio is deduced to be $\xi$ = 0.73, close to unity, which suggests that the independent-electron description works well for $CaC_6$, without complications arising from correlation and many-body effects.

홍바리, Epinephelus fasciatus 정자의 미세구조

김성훈,이치훈,송영보,주해성,김형배,이영돈,Kim, Seong-Hoon,Lee, Chi-Hoon,Song, Young-Bo,Ju, Hea-Sung,Kim, Hyung-Bae,Lee, Young-Don 한국현미경학회 2012 Applied microscopy Vol.42 No.2

Ultrastructural characteristics of blacktip grouper, Epinephelus fasciatus spermatozoa were investigated using transmission and scanning electron microscopy. The spermatozoa of E. fasciatus consisted of a spherical head part, a midpiece with cytoplasmic canal entrance and a flagellum with lateral fins. Internal ultrastructurally, the nucleus contains high electron dense chromatin having granular particles and has no acrosome. The centriolar complex lies outside of the nuclear fossa and it is connected by the osmophilic filaments. Also the osmophilic filaments connect between the centriolar complex and the nuclear membrane. The midpiece contains eight to nine spherical mitochondria, cytoplasmic canal and necklaces. The flagellum has a typical 9+2 axonemal structure. The lateral fins contain vesicles and a typical 9+2 axonemal structure. Consequently this study contributes to comparative grouper spermatology and provide useful systematic taxonomic characters. 홍바리, Epinephelus fasciatus 정자의 미세구조적 특징을 주사형 및 투과형 전자현미경으로 관찰하였다. 홍바리 정자는 구형의 두부와 cytoplasmic sleeve와 고리형 cytoplasmic canal 입구 등으로 구성된 중편부 그리고 lateral fin을 갖는 1개의 편모로 구성된 미부로 구별된다. 정자의 핵은 구형이며, 첨체 구조물은 존재하지 않으나 이질 염색질이 과립상 덩어리 형태로 조밀하게 분포하였다. Proximal centriole과 distal centriole은 각각 수레바퀴형의 "9+0"의 축사구조를 보이며 서로 수직으로 osmophilic filaments 연결되어 있고, 핵막과도 연결되어 있었다. 중편부는 구형의 8~9개의 미토콘드리아를 포함하며, 빈공간인 cytoplasmic canal과 편모 원형질막에는 7~8개의 구형 입자를 갖는 necklace가 존재하였다. 미부는 1개의 편모를 갖으며 전형적인 "9+2"의 축사구조를 보였고, 편모에는 다양한 형태의 lateral fins을 관찰할 수 있었다. 홍바리 정자의 미세구조적 특징은 바리과 어류의 정자와 상이하여 계통분류학적 동정의 형질이 될 수 있을 뿐만아니라 정자 세포소기관의 기능적 및 생리학적 연구에 이용될 수 있다고 판단된다.

Q-행렬에 근거하는 치유교습 순서

김성훈(Sung Hoon Kim) 한국교육평가학회 2020 교육평가연구 Vol.33 No.2

이 연구는 인지진단 결과로 주어지는 미성취 인지요소의 치유교습 순서에 Q-행렬이 어느 정도로 어떻게 결정하는지 탐색하였다. Tatsuoka(2009)가 소개한 인접행렬, 도달행렬, 그리고 영향도표를 이용하여 Q-행렬에 내재하는 인지요소 간의 인과관계를 치유교습의 순서로 개념화하였다. 이 연구 결과로 제안한 Q-행렬의 치유교습 순서 기여도는 그 행렬에 포함된 K개의 인지요소 간 있을 수 있는 모든 인과관계의 수에 대한 실제 Q-행렬에 내재하는 인과관계 수의 비율로 정의하였다. 분석 대상 Q-행렬은 이 이론적 배경에 사용된 예시적 Q-행렬과 실제 Q-행렬 2개다. 후자는 성태제(2018) 연구와 박세진·이현숙(2018) 연구에서 인용하였다. 연구 결론으로서 Q-행렬은 치유교습 순서 결정을 위한 보편적 출발점이 되며; 지식의 위계가 분명한 검사일수록 Q-행렬의 치유교습 순서 기여도는 높을 것이며; 인지진단 결과로 주어지는 인지상태는 Q-행렬의 가정과 충돌할 수 있음 등이 논의되었다. This study was to investigate how and how much does a Q-matrix contribute in deciding the sequence of remedial instruction of the unattained attributes being identified from cognitive diagnostic assessment. Applying the adjacency matrix, reachability matrix, and influence diagram introduced in cognitive assessment context by Tatsuoka (2009), the sequence was defined as the causal relationship among attributes forming a Q-matrix. Three Q-matrices were gone under analysis. They were an example one, one from Sung’s(2018) study, and the other from Park & Lee’s(2018) study. The results were discussed into three conclusions. Firstly, the Q- matrix could provide a objective starting point for a whole sequence of remedial instruction; secondly, the more hierarchical a Q- matrix was the more it helped deciding sequence of remedial instruction; thirdly, knowledge states from cognitive diagnosis might contradict the causal relationship assumptions implied by the Q-matrix.

홍바리, Epinephelus fasciatus의 인공수정 전.후 난문의 미세구조적 변화

김성훈,이치훈,주해성,김형배,이영돈,Kim, Seong-Hoon,Lee, Chi-Hoon,Ju, Hea-Sung,Kim, Hyung-Bae,Lee, Young-Don 한국현미경학회 2011 Applied microscopy Vol.41 No.2

홍바리, Epinephelus fasciatus 난의 인공수정 전 후 난문의 미세구조적 특징을 주사형 전자현미경으로 관찰하였다. 홍바리 난문($6.6{\pm}0.41\;{\mu}m$)은 원통형의 분화구형으로 동물극에 1개가 존재하였다. 난문의 vestibular ridge는 시계방향성을 갖는 6~7개의 나선형의 내벽구조로 구성되었다. 난문의 내벽구조물인 나선형의 vestibular ridge는 인공수정 후 부풀어 올라와 돔(dome)형의 수정구로 분화 형성되었다. 홍바리 난은 부상란으로 난막표면에는 pore 가장자리에 고리형의 nodule과 pore 사이에 돌기형의 nodule이 관찰되었으나, 부착사와 유사한 보조 구조물은 관찰할 수 없었다. 난문 주변부에는 동심원상으로 크기가 다른 pore (0.15~0.55 ${\mu}m$)들이 개구된 형태로 혼재하였고, 수정 후 돔(dome)형의 수정구가 분화 형성되면서 pore들이 닫히는 현상을 보였다. 홍바리 난문의 미세구조적 특징은 바리과 어종간에 형태학적으로 상이하여, 바리과 어류의 계통분류학의 형질로 이용될 수 있다고 판단된다. The micropyles on the prefertilized and artificial fertilized eggs of Epinephelus fasciatus were investigated using scanning electron microscope (SEM). The micropyles ($6.6{\pm}0.41\;{\mu}m$) of E. fasciatus eggs were found in the animal pole and theirs shape were observed as a flat crateriform of cylindrical shape. The micropylar vestibule arranged by 6~7 thickened spiral annuli on the ridge and contributed to differentiate and form fertilization cone for blocking to polyspermy by presenting swollen vestibule structure. As E. fasciatus eggs was pelagic, so chorionic surface was an uneven structures such as circular and fillar form nodules. Especially, various pores (0.15~0.55 ${\mu}m$, 230~270 pores) distributed at the only around micropyles, those pores radiately exhibited regular projection structures showing gill filament-shape. These ultrastructural characters of E. fasciatus eggs can be utilized in a taxonomical cue of grouper species.

역기하렌즈 착용 전 요인들이 착용 후 시력에 미치는 영향

김성훈,이정훈,김춘식,Sung Hoon Kim,Jung Hoon Lee,Chun Sik Kim 대한안과학회 2010 대한안과학회지 Vol.51 No.10

Purpose: To determine whether patient factors (pre-fitting patient’s data) before reverse-geometry lens (RGL) use could be predicting factors for the increase in visual acuity after RGL use. Methods: The authors reviewed out patient records of 805 eyes of 423 patients wearing RGLs from March 2003 to May 2009. The relationship between patient factors on UVA before wearing a RGL examined at follow-ups and the IVA after wearing a RGL were analyzed. Results: The spherical refractive errors and the cylindrical refractive errors showed statistically significant results (p < 0.05). The lower was the refractive error, the greater were the UVA and IVA results. Correlations existed between the corneal astigmatism and UVA or IVA at three months (p < 0.05). The lower was the corneal astigmatism, the greater were the UVA and IVA results. Correlations were observed between the initial visual acuity and IVA, although the initial visual acuity cannot be a predictor. The other factors evaluated did not show statistically significant results (p > 0.05). Conclusions: The refractive error and the corneal astigmatism may be strong predictors of UVA and IVA after RGL use. J Korean Ophthalmol Soc 2010;51(10):1305-1311

흡수선량 측정 시 동종 원통형 이온함에서 이온함 간 변화

김성훈,허현도,최상현,김혁주,임천일,신동오,최진호,Kim, Seong-Hoon,Huh, Hyun-Do,Choi, Sang-Hyun,Kim, Hyeog-Ju,Lim, Chun-Il,Shin, Dong-Oh,Choi, Jin-Ho 한국의학물리학회 2010 의학물리 Vol.21 No.1

물흡수선량에 기반한 표준 측정법을 사용하여 흡수선량을 측정 시에 여러 요인들이 크건, 작건, 미미하건 간에 선량 측정의 정확성에 영향을 미칠 수 있다. 이온함의 선질 보정 인자(the beam quality correction factor) ${\kappa}_{Q,Q_0}$ 값 또한 그 중 한 요인이 될 수 있다. 본 연구에서는 특정 이온함 유형(PTW30013, PTW, Germany)을 선정하여, 국내에서 사용하고 있는 기관들로부터 9개의 이온함을 수집하였다. 동일한 전위계와 전기선으로 9개 이온함을 국내 이차표준기관으로부터 교정을 받았다. 이렇게 교정받은 이온함들을 사용하여 Siemens ONCOR 장비의 광자 빔 6 MV와 10 MV 그리고 전자 빔 12 MeV에 대해 기준 조건하에서 흡수선량을 측정하였다. 이온함 간 선량 값의 최대 차이는 광자 빔 6 MV의 경우엔 2.4%, 10MV의 경우에 0.8%, 전자 빔 12 MeV의 경우엔 0.8%이었다. 6 MV에서의 큰 차이는 측정 과정에 문제가 없었다면, 동일한 ${\kappa}_{Q,Q_0}$ 값을 모든 이온함에 적용한 게 한 요인이 될 수 있다. 이는 또한 외부 독립검사가 왜 중요한지를 보여 주는 예라 하겠다. For the measurements of an absorbed dose using the standard dosimetry based on an absorbed dose to water the variety of factors, whether big, small, or tiny, may influence the accuracy of dosimetry. The beam quality correction factor ${\kappa}_{Q,Q_0}$ of an ionization chamber might also be one of them. The cylindrical type of ionization chamber, the PTW30013 chamber, was chosen for this work and 9 chambers of the same type were collected from several institutes where the chamber types are used for the reference dosimetry. They were calibrated from the domestic Secondary Standard Dosimetry Laboratory with the same electrometer and cable. These calibrated chambers were used to measure absorbed doses to water in the reference condition for the photon beam of 6 MV and 10 MV and the electron beam of 12 MeV from Siemens ONCOR. The biggest difference among chambers amounts to 2.4% for the 6 MV photon beam, 0.8% for the 10 MV photon beam, and 2.4% for the 12 MeV electron beam. The big deviation in the photon of 6 MV demonstrates that if there had been no problems with the process of measurements application of the same ${\kappa}_{Q,Q_0}$ to the chambers used in this study might have influenced the deviation in the photon 6 MV and that how important an external audit is.

주조 포스트의 유지력에 관한 연구

김성훈,조혜원,진태호,Kim Sung-Hoon,Cho Hye-Won,Jin Tai-Ho 대한치과보철학회 1993 대한치과보철학회지 Vol.31 No.4

The purpose of this study was to evaluate the effects of method for construction of cast post and type of dental cement on the retention of cast post. The wax patterns or Duralay resin patterns were used for construction of cast post. The dental cements used in this study were zinc phosphate cement(Fleck's zinc cement, Mizzy INc., U.S.A.), glass ionomer cement(Fuji I, G-C Co., Japan), and resin cement(Panavia-EX, Kuraray Co., Japan) and the retention of cast post was measured with Instron Universal Test Machine(Instron Engineering Co., U.S.A.). The obtained results were as follows : 1. The tensile bond strength of cast posts made by Duralay resin patterns revealed 39.13(kg) with Panavia-EX, 46.40(kg) with phosphate cement, and 37.78(kg) with glass ionomer cement. 2. The tensile bond strength of cast posts made by wax patterns revealed 39.25(kg) with Panavia, EX, 44.12(kg) with phosphate cement, and 40.23(kg) with glass ionomer cement. 3. The tensile bond strength of cast posts made by Duralay resin patterns or wax patterns were not affected by the type of dental cements(P>0.05).

변동하중하의 잔류응력을 고려한 십자형 용접부의 잔존 수명 예측에 관한 연구

김성훈,김경수,이장현,유창혁,유원효,유미지,Kim, Sung-Hoon,Kim, Kyung-Su,Lee, Jang-Hyun,Yoo, Chang-Hyuk,You, Won-Hyo,Yoo, Mi-Ji 대한용접접합학회 2011 대한용접·접합학회지 Vol.29 No.2

This paper deals with the crack propagation life assessment of T-joint welded structure where typical fatigue cracks have been frequently initiated when the marine vessels experience the storm load. Welding residual stresses are calculated to investigate its effects on the fatigue life. Thereafter the residual stress distribution was applied to the AFGROW life prediction program, which incorporated the loading, the welding residual stress, and the geometric shape of the structure. The fatigue tests of the T-joint welded specimen under storm loading show the beach mark clearly generated on the fractured section of the weldment. The crack propagation life estimated based on the beach mark is compared with that of AFGROW to validate the life prediction. Based on the results, the evaluation method of the remaining fatigue life for T-joint fillet weldment of marine vessel's cargo hold with random load or storm load was established.

The effect of captafol on the hematological value, erythrocyte membrane and plasma biochemical value in vitro

김성훈,황화선,차신우,한상섭,노정구,Kim, Sung-hoon,Hwang, Hwa-seon,Cha, Shin-woo,Han, Sang-seop,Roh, Jung-koo The Korean Society of Veterinary Science 1993 大韓獸醫學會誌 Vol.33 No.3

Captafol은 phthalimide계통의 항진균제로써 difolatan이란 상품명으로 개발되어 과일, 채소의 탄저병 및 원목 등의 곰팡이 구제에 널리 사용되고 있는 것으로 국내에서도 두번째로 많이 생산, 사용되는 품목이나 독성실험에 관한 보고는 거의 없는 상태이다. 이에 본 연구에서는 captafol 자체에 대한 독성기전의 일부를 확인하고자 동물체내에서 일어나는 여러가지 대사작용이 배제된 시험관내에서 실험을 수행하였다. 랫트 혈액을 후대정맥으로 부터 채혈하여 4개의 시험관에 $2.5m{\ell}$씩 분주한 후 captafol 농도가 $0.1{\times}10^{-4}M$, $1{\times}10^{-3}M$, $1{\times}10^{-2}M$이 되도록 한 ethanol용액 $25{\mu}{\ell}$씩 넣고 $CO_2$ incubator에서 2시간 동안 부드럽게 혼합하여 혈액학적 성상 및 적혈구 취약성 시험을 수행하였다. 또한 원심분리하여 얻어진 혈장에서 생화학적 성상 등을 조사한 결과 다음과 같은 성적을 얻었다. 1. 적혈구수 및 hematocrit치는 captafol 투여량에 비례적으로 유의한(p<0.05) 감소를 나타내었다. 2. 적혈구막 취약성 실험에서 $1{\times}10^{-3}M$ 및 $1{\times}10^{-2}M$ 농도에서 대조군에 비하여 유의한(p<0.01) 증가를 나타내었다. 3. 혈장내 potassium이온의 농도는 captafol의 투여량에 비례적으로 증가하였다. 4. Total bilirubin 및 creatine kinase가 대조군에 비하여 각각 증가 및 감소하였다. The effect of captafol on the hematological value, erythrocyte membrane and plasma biochemical value was investigated using blood of SPF Sprague-Dawley male rats in vitro. For the anticoagulations, we used 0.5mg of heparin per $10m{\ell}$ of blood from vena cava. Three con-centrations($0.1{\times}10^{-4}M$, $1{\times}10^{-3}M$ and $1{\times}10^{-2}M$) captafol in ethanol were added to the each $2.5m{\ell}$ blood so that the linal concentration of ethanol was 1%. The blood contained with each concentration of captafol was incubated at $37^{\circ}C$ C for 2 hours under 5% $CO_2$ gas The whole blood and plasma were examined for hematological vaJues, erythrocyte membrane damage and biochemical values, respectively. The results obtained were summarized as follows ; 1. The number of RBC in $1{\times}10^{-2}M$ group and the concentration of MCHC in $1{\times}10^{-3}M$ group were significantly (p<0.05) decreased and increased from that of control values, respectively. The percentage of Hct was significantly (p<0.05) decreased with dose-response. 2. Erythrocyte fragility rate of $1{\times}10^{-3}M$ and $1{\times}10^{-2}M$ group were significantly (p<0.01) increased from that control with dose response. 3. Potassium ion level of $1{\times}10^{-2}M$ was significantly (p<0.05) increased from that of control. 4. The concentration of total bilirubin in the $1{\times}10^{-3}M$ and $1{\times}10^{-2}M$ groups were significantly increased from that of control. The enzyme level of creatine kinase in $1{\times}10^{-2}M$ group was significanlty (p<0.05) decreased from control value.

점진적 체중지지와 보행속도 증가 훈련이 뇌졸중 환자의 보행에 미치는 효과

김성훈,최종덕,Kim, Sung-Hoon,Choi, Jong-Duk 대한물리치료학회 2013 대한물리치료학회지 Vol.25 No.5

Purpose: The aim of this study was to evaluate the effect of progressive body weight decrease combined with increasing level of overground walking speed training for patients with chronic stroke. Methods: Eighteen subjects with chronic stroke were composed of the control group (5% body weight support combined with increasing speed training) and the experimental group (progressive body weight decrease with increasing speed training); three sets, three times per week over a period of four weeks. Results: Significant differences in terms of comfortable gait speed (CGS) and the rate of change of CGS were observed between the control and experimental groups (p<0.05). However, no significant difference in the dynamic gait index was observed between the control and experimental groups (p>0.05). A significant difference in the 6 minute walking test (6MWT) was observed for the experimental group, and a significant difference in the rate of change for the 6MWT was observed between the control and experimental groups (p<0.05). Conclusion: The progressive body weight decrease combined with increasing in level of overground walking speed training may be a better and more effective method for community walking and reintegration.