• 대한임상검사과학회지
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• 제44권3호
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• pp.136-141
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• 2012

The hearts of highly trained athletes show morphologic and electrocardiographic (ECG) changes that suggest the presence of cardiovascular disease, including sinus bradycardia, a striking increase in precordial R-wave or S-wave voltages, ST segment depression, and T-wave inversions. Despite a number of previous observational surveys, the determinants of abnormal ECG patterns in trained athletes remain largely unresolved. In this study, we compared the electrocardiographic characteristics of athletes to determine any sensitive indicators. Comparison between ECG patterns and cardiac physiology was performed in 21 junior athletes and 25 untrained subjects with no signs of cardiac disease. Sinus bradycardia was detected in a subset of athletes but not statistically significant between the athletes ($69.9{\pm}11.1bpm$) and the control ($72.7{\pm}9.9bpm$) group. The mean values of the PR and QTc intervals in the athletes' group were $149.2{\pm}15.4ms$ and $402.3{\pm}28.8ms$, respectively. Also, there were no significantly differences between control group and the athletes' group. In addition, the athletes demonstrated a spectrum of alterations in the 12-lead ECG pattern, including marked increase in precordial R-wave or S-wave voltages ($$SV_1+RV_5{\geq_-}35mm$$, 23.8%), QRS duration ($${\geq_-}90ms$$, 90.5%), suggestive of left ventricular hypertrophy. However, left axis deviation, ST segment depression, and T-wave changes in V5, V6 were not observed in either the athletes or control group. Our findings suggest that sinus bradycardia, precordial R-wave or S-wave voltages, and QRS duration seem to be more sensitively detected in athletes than in control group. Further researches on the electrocardiographic patterns of athletes should be carried out to improve the sensitivity and specificity of diagnostic criteria.

• Asian-Australasian Journal of Animal Sciences
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• 제14권10호
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• pp.1367-1373
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• 2001

This study used fowl sperm from three White Leghom rooster reared at our laboratory. Semen samples were exposed to the magnetic field strengths of from 650 to 5700 Gauss for one. two, or three days to investigate the influence of magnetic field on the orientation of fowl spermatozoa. Fowl spermatozoa were found to orient with their long axis of heads perpendicular to the magnetic field direction. The fowl spermatozoa were initially influenced when magnetic field intensities were from 650 to 5700 Gauss and the highest values (70.67, 72.49 and 71.79%) were found in the 5700 Gauss treatment at one, two, and three days exposure, respectively. Although percentages of the perpendicular oriented fowl spermatozoa increased along with the enhancement of the magnetic field intensity, the degree of orientation was only significantly higher in the treatments having the magnetic field strength from 1500 to 5700 Gauss than that in the control treatment at all exposure time. In addition, the experimental results also showed that the percentages of all orientational types of fowl spermatozoa (perpendicular category including upward perpendicular and downward perpendicular and parallel type consisting of leftward parallel and rightward parallel) in all treatments tended to be stable during exposure time. From the results of this study. it is suggested that (1) the diamagnetic anisotropy of the inside structural components of fowl spermatozoa induce them to orient perpendicular to the magnetic field direction, (2) the degree of orientation increased according to the enhancement of magnetic field strengths, (3) fowl spermatozoa had not an high sensitivity to the magnetic field, and the level of perpendicular orientation of fowl spermatozoa in this study is nearly similar to that of cattle sperm in the study of Suga et al. (2000).

• 한국전기전자재료학회논문지
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• 제17권5호
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• pp.508-514
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• 2004

A fluxgate magnetic sensor consists of a solenoid excitation coil, pick-up coil, and magnetic core. We presents the effect of magnetic core shape in a micromachined fluxgate sensor. To observe the performance of fluxgate sensor with magnetic core side width and gap, side width of 125 ${\mu}{\textrm}{m}$, 250 ${\mu}{\textrm}{m}$, and 500 ${\mu}{\textrm}{m}$ were designed in a rectangular-ring shaped core and the gaps of 0 ${\mu}{\textrm}{m}$, 50 ${\mu}{\textrm}{m}$, and 100 ${\mu}{\textrm}{m}$ were also fabricated in a racetrack shaped core. The solenoid coils and magnetic core were separated by benzocyclobutane(BCB) which had high insulation and good planarization characters. Copper coil patterns of 10 ${\mu}{\textrm}{m}$ width and 6${\mu}{\textrm}{m}$ thickness were electroplated on Ti(300 $\AA$) / Cu(1500 $\AA$) seed layers. 3 ${\mu}{\textrm}{m}$ thick N $i_{0.8}$F $e_{0.2.}$(permalloy) film for the magnetic core was also electroplated under 2000 gauss to induce the magnetic anisotropy. The magnetic core had the high DC effective permeability of ∼1,300 and coercive field of ∼0.1 Oe. Because the magnetic cores of 500 ${\mu}{\textrm}{m}$ side width and 0 gap had a low magnetic flux leakage, high sensitivity of ∼350 V/T were measured at excitation condition of 3 $V_{P-P}$ and 2 MHz square wave. The power consumption of ∼14 ㎽ was measured. The fabricated fluxgate sensor had the very small actual size of 3.0${\times}$1.7 $\textrm{mm}^2$. When two fluxgates were perpendicularly aligned in terrestrial field, their two-axis output signals were very useful to commercialize an electronic azimuth compass for the portable navigation system.m.m.m.

• 한국진공학회지
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• 제1권1호
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• pp.126-133
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• 1992

E-Beam 기법을 이용하여 증착시킨 Ag doped CdS 박막은 육방정계이고 공기, Ar 분위기에서 $^550{\circ}C$로 열처리한 결과 grain size가 1$mu extrm{m}$ 정도로 성장되었고, Van Der Pauw 방법으로 구한 Hall data로부터 CdS crystal은 n형 반도체이고 상온에서의 carrier 농 도는 2.7 $\times$ 1011cm-3이고 Hall mobility는 5.8 $\times$ 102cm2V-1sec-1정도임을 알 수 있었다. CdS : Ag 박막의 PL spectra는 Gaussian curve를 보여주었고, spectra peak는 파장이 520nm 근처에 위치하고 있으며, CdS : Ag 박막에서의 광전류(pc)와 암전류(dc)의 ratio(pc/dc)는 공기 중에서 열처리한 시료의 값이 크다는 것을 알 수 있었다.

• 센서학회지
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• 제8권6호
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• pp.427-433
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• 1999

본 논문은 페라이트 코어, 여자코일과 픽업코일로 구성된 1축 fluxgate 마그네틱 센서를 제안하였다. 본 마그네토미터는 검출소자, 여자코일을 위한 드라이브 회로, 픽업코일 출력으로부터 DC 자장에 비례한 제 2고조파 성분검출을 위한 신호처리 회로로 구성하여 회로를 설계하고 제작하였다. 코어는 82회의 여자코일을 통해 구형파전압으로 여자하였다. 픽업 코일(150 회)의 제 2고조파 출력은 FFT 스펙트럼 분석기로 측정하였으며, 그 결과를 제 2 고조파 성분 검출을 위한 PSD(phase sensitive detector)단의 출력과 비교하였다. 감도는 구동주파수 2 (kHz)에서 약 50 [V/T]의 결과를 얻었으며, fluxgate 마그네틱 센서의 비선형계수는 약 2.0% 정도였다.

• 한국항공우주학회지
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• 제33권4호
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• pp.47-56
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• 2005

무인기의 INS/GPS/기압고도계 결합항법 시스템에서 수직채널감쇠루프를 사용하여 고도 오차를 보정할 때 비행 고도의 오차를 감소시키기 위해서 기압고도계의 정밀도를 향상시켜야한다. 피토정압관을 사용하여 기압 고도를 측정할 때 비행 속도와 자세 등의 변화에 따라 피토정압관 주위의 압력이 변하여 정압 오차에 의한 기압 고도의 오차를 유발한다. 정압 오차를 보정하기 위하여 풍동 시험과 CFD, 비행 시험 등의 자료를 이용하여 피토정압관 측정 압력의 변화를 분석하고 받음각과 비행 속도에 따른 압력 오차의 모델을 수립하였다. 비행 속도 변화에 의한 오차를 보정하기 위하여 피토정압관의 차압과 차압/정압 비를 사용한 두 가지 오차 모델에 대하여 압력 섭동에 대한 민감도 해석을 하였고 비행 시험에 적용하여 차압/정압 비를 사용한 모델이 고고도 비행 특성이 우수하다는 결론을 얻었다.

• Journal of Oral Medicine and Pain
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• 제41권2호
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• pp.48-53
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• 2016

Purpose: The purpose of this study was to compare the differences in clinical signs and symptoms, and psychological profiles of temporomandibular joint osteoarthritis (TMJ OA) between juvenile and adult patients. Methods: Two-hundred eighty-three TMJ OA patients who visited the Orofacial Pain Clinic of Seoul National University Dental Hospital were classified by juvenile (153 patients; mean age $14.2{\pm}1.7$ years, range 9-16 years) and adult (130 patients; mean age $34.0{\pm}2.8$ years, range 30-40 years) groups, and compared the clinical symptoms based on the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) axis I guidelines including Graded Chronic Pain (GCP) scale, mandibular range of motion, and the associated symptoms. Psychological profiles were also evaluated using the Symptom Checklist 90-Revision (SCL-90-R). Results: Juvenile patients reported lower pain intensity and a lower prevalence of headache and clenching than adult patients. Their mandibular range of motion was also higher than adult patients. Juvenile patients showed a lower percentage of patients with T-score above 50 in somatization (SOM), obsessive-compulsive (O-C), interpersonal sensitivity (I-S), and paranoid ideation (PAR) than adults. Based on the GCP scale, the percentage of the high disability group was lower in juveniles. Conclusions: Juvenile TMJ OA patients generally showed milder clinical symptoms than adults. Adult patients showed higher prevalence of psychological problems and higher disability than juvenile patients. Age should be considered in evaluation and treatment of TMJ OA patients to achieve better treatment results and understanding its pathophysiology.

• 한국통신학회논문지
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• 제31권11A호
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• pp.1053-1058
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• 2006

본 논문은 GE-PON 등 FTTH용 광액세스망 시스템에 사용되는 저가격 광모듈 제작을 위하여, 1.31/1.49um 양방향 구성의 하이브리드집적 PLC칩을 사용한 효율적인 광모듈 패키징 기술을 제안하였다. 수동 광섬유정렬기술과 nonhermetic 플라스틱 패키지 기술을 적용하여 광모듈을 제작하였으며, 광결합효율과 전기-광학적 특성을 측정하였다. 제작된 광모듈의 광결합효율은 광축정렬 허용오차 40um내에서 0.5dB이하의 광결합손실을 나타내었고, -24dBm 이하의 수신감도와 광출력 1.5mW이상, 소광비 10dB이상, tracking error 0.3dB이하의 온도특성이 GE-PON ONU용 광모듈 규격을 만족함을 확인하였다.

• 센서학회지
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• 제29권6호
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• pp.407-411
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• 2020

In this study, we propose an array-type gas sensor with high selectivity and response using multiple oxide semiconductors. The sensor array was composed of SnO₂ and In₂O₃, and the detection characteristics were improved by using Pt, Au, and Pd catalysts. All samples were deposited directly on the Pt interdigitated electrode (IDE) through the e-beam evaporator glancing angle deposition (GAD) method. They grew in the form of well-aligned nanorods at off-axis angles. The prepared SnO₂ and In₂O₃ nanorod samples were exposed to CH₃COCH₃, C₇H₈, and NO₂ gases in a 300℃ dry condition. Au-decorated SnO₂, Au-decorated In₂O₃, and Pd-decorated In₂O₃ exhibited high selectivity for CH₃COCH₃, C₇H₈, and NO₂, respectively. They demonstrated a high detection limit of the sub ppb level computationally. In addition, measurements from each sensor were executed in the 40% relative humidity condition. Although there was a slight reduction in detection response, high selectivity and distinguishable detection characteristics were confirmed.

• Journal of Korean Neurosurgical Society
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• 제60권5호
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• pp.567-576
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• 2017

Objective : Preoperative parameters including the T1 slope (T1S) and C2-C7 sagittal vertical axis (SVA) have been recognized as predictors of kyphosis after laminoplasty, which is accompanied by posterior neck muscle damage. The importance of preoperative parameters has been under-estimated in anterior cervical discectomy and fusion (ACDF) because there is no posterior neck muscle damage. We aimed to determine whether postoperative subsidence and pseudarthrosis could be predicted according to specific parameters on preoperative plain radiographs. Methods : We retrospectively analyzed 41 consecutive patients (male : female, 22 : 19; mean age, $51.15{\pm}9.25years$) who underwent ACDF with a stand-alone polyether-ether-ketone (PEEK) cage (>1 year follow-up). Parameters including SVA, T1S, segmental angle and range of motion (ROM), C2-C7 cervical angle and ROM, and segmental inter-spinous distance were measured on preoperative plain radiographs. Risk factors of subsidence and pseudarthrosis were determined using multivariate logistic regression. Results : Fifty-five segments (27 single-segment and 14 two-segment fusions) were included. The subsidence and pseudarthrosis rates based on the number of segments were 36.4% and 29.1%, respectively. Demographic data and fusion level were unrelated to subsidence. A greater T1S was associated with a lower risk of subsidence (p=0.017, odds ratio=0.206). A cutoff value of T1S<$28^{\circ}$ significantly predicted subsidence (sensitivity : 70%, specificity : 68.6%). There were no preoperative predictors of pseudarthrosis except old age. Conclusion : A lower T1S (T1S<$28^{\circ}$) could be a risk factor of subsidence following ACDF. Surgeons need to be aware of this risk factor and should consider various supportive procedures to reduce the subsidence rates for such cases.