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

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.

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.

$^{13}C$ 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.

Enhancement of Low Temperature Selective Deposition of Diamond Film

김성훈,Kim, Sung Hoon Korean Chemical Society 2001 대한화학회지 Vol.45 No.3

삼차신경통에 대한 미세혈관감압술의 효과

김성훈,최창화,Kim, Sung-Hoon,Choi, Chang-Hwa 대한신경외과학회 2005 Journal of Korean neurosurgical society Vol.37 No.5

Objective: The microvascular decompression(MVD) for trigeminal neuralgia(TN) is known as an effective surgical technique. But the failed MVD cases have been reported in long term follow-up studies. This study is to evaluate the efficacy of MVD through our operative techniques, offending vessels in operative field, failed cases with the review of the literatures. Methods: We analyzed total 63 cases of TN which underwent MVD from 1955 to 2003 according to characters of pain, operative findings, operative results related to causative vessel compression and operative method, progonotic factor. Statistical analysis was performed using paired t-test with SPSS Ver 11.0. Results: In TN, the most common offending vessel was superior cerebellar artery(45.0%). In compression group of nerve root by offending vessel, the cure rate was 91.7%. However, the cure rate of the contact group was 64.7% and the cure rate of the negative group was 37.5%. There was no statistical significance between the degree of compression by vessel and the operative result(p=0.076). In 51 cases with MVD only, the cure rate was 84.3% and in 3 cases with PSR only, 42.8% and in 2 cases with PSR(partial sensory rhizotomy) with MVD, 50.0%. TN recurred in 7 cases within the follow-up period and reoperations(PSR) were added in 2 cases of them. Conclusion: This study shows that MVD provided a high rate of success with a minor risk of complications, which has been regarded as the most safe and effective procedure for trigeminal neuralgia. Additional MVD in recurred TN by severe adhesion of teflon showed poor outcome. But, revisional operation(PSR) in recurred TN showed relatively good outcome. PSR should be considered for treatment of recurrent TN after MVD.

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.

고장력 볼트 이음부의 내부 압축응력 분포

김성훈,이승용,최준혁,장동일,Kim, Sung Hoon,Lee, Seung Yong,Choi, Jun Hyeok,Chang, Dong Il 한국강구조학회 1997 韓國鋼構造學會 論文集 Vol.9 No.2

고장력 볼트 이음부에서의 힘의 전달은 부재간의 압축력 및 볼트축력에 의하여 외력과 균형을 이룸으로서 형성되어지며, 부재간의 압축력, 도입된 축력의 변화 및 미끄러짐하중 등은 볼트 체결부 및 볼트의 유효강성에 지배된다. 이때 유효강성은 일반적으로 접합부의 유효단면적과 탄성계수의 곱으로 나타내어지지만 접합부재의 유효단면적이 어느 정도가 되는지는 판단하기가 쉽지가 않다. 이를 위해서 종래에는 이음부의 탄성변형에 관계하는 유효단면적을 등가중공원통형으로 가정하여 이에 대한 여러 가지 검토가 이루어졌다. 그러나 이러한 제안식들은 설계상의 목적과 복잡한 계산을 피하기 위하여 매우 단순화시킨 것으로 어느 식이 타당한 지는 단정하기가 어려우며 이에 대한 상세한 해석적인 검토 및 실험적인 검증이 요구된다. 따라서, 본 연구에서는 볼트 축력에 의한 접합부재의 유효단면적 산정과 이에 대한 검증을 위하여 고장력 볼트 이음 시험편에 대해 피로시험을 실시하고 반복하중 재하 후의 마찰면의 형상을 관찰하여 유효마찰 영역을 측정하였으며, 유한 요소법에 의해 수치 해석을 실시하여 내부 압축응력의 분포형상을 밝히고 접촉면상에 발생하는 응력 분포영역을 근사화하므로서 마찰면의 형상과 내부 압축응력의 분포영역과의 관계 그리고 유효단면적의 산정 방법을 고찰하였다. The high-tension bolted joints are clamped by the axial force which approaches the yielding strength. The introduced axial force is transmitted to the connection members pass through washer. The transferred load in connections is balanced to the compressive stress of plates, axial force in bolts and the external loads. In this mechanism, the compressive stress and slip load we dominated by the effective stiffness of bolted joints and plates. In general the effective stiffness is specified to product to the effective area and elasticity modulus in connections. In this reason, the conic projection formular which is assumed that the axial force in bolts is distributed to the cone shape and that region is related to the elastic deformation mechanism in connections, was proposed. But it conclude what kind of formula is justified. Therefore in this paper, the fatigue tests are performed to the high tension bolted joints and inspected to the phase on the friction face. And using the FEM and numerical method, it is analyzed and approximated to the compressive stress distribution and its region. Moreover, it is estimated to the effective area and to the relation the friction area to the effective compressive distribution region.

SONET 통신 시스템을 위한 $8{\sim}10.9$ GHz 저 위상 잡음과 넓은 튜닝 범위를 갖는 새로운 구조의 LC VCO 설계

김성훈,조효문,조상복,Kim, Seung-Hoon,Cho, Hyo-Moon,Cho, Sang-Bock 대한전자공학회 2008 電子工學會論文誌-SD (Semiconductor and devices) Vol.45 No.1

In this paper, New LC VCO with $8{\sim}10.9$ GHz Band has been designed using commercial $0.35-{\mu}m$ CMOS technology. This proposed circuit is consisted of the parallel construction of the typical NMOS and PMOS cross-coupled pair which is based on the LC tank, MOS cross-coupled pair which has same tail current of complementary NMOS and PMOS, and output buffer. The designed LC VCO, which is according to proposed structure in this paper, takes a 29% improvement of the wide tuning range as 8 GHz to 10.9 GHz, and a 6.48mW of low power dissipation. Its core size is $270{\mu}m{\times}340{\mu}m$ and its phase noise is as -117dBc Hz and -137dBc Hz at 1-MHz and 10-MHz offset, respectively. FOM of the new proposed LC VCO gets -189dBc/Hz at a 1-MHz offset from a 10GHz center frequency. This design is very useful for the 10Gb/s clock generator and data recovery integrated circuit(IC) and SONET communication applications. 본 논문에서는 $0.35-{\mu}m$ CMOS 공정을 이용 $8{\sim}10.9$ GHz 밴드를 갖는 새로운 구조의 LC VCO를 설계 제안하였다. 이 회로 구성은 LC 탱크 기반의 전형적인 NMOS, PMOS cross-coupled 쌍을 병렬로 구성한 새로운 구조로 상보적인 NMOS와 PMOS 꼬리 전류와 같은 MOS cross-coupled쌍과 출력 버퍼로 구성하였다. 본 논문에서 제시한 구조로 설계된 LC VCO는 8GHz에서 10.9GHz까지로 29%의 증가된 튜닝 범위와 6.48mV의 낮은 전력소모를 가지는 것을 확인하였고 이의 core size는 $270{\mu}m{\times}340{\mu}m$, 시뮬레이션을 통한 VCO의 위상잡음은 1MHz와 10MHz offset에서 각각 -117dBc/Hz와 -137dBc/Hz이다. FOM은 10GHz의 중심 주파수으로 부터 1MHz offset에서 -189dBc/Hz를 가진다. 제안한 설계방법은 10Gb/s급의 클럭과 데이터 복원회로 그리고 SONET 통신응용에 매우 유용하다.