• 한국광학회지
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• 제17권1호
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• pp.54-59
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• 2006

본 논문에서는 집적 광학 광도파로 소자 기술을 적용하여 생화학 물질의 성분을 정밀하게 측정 가능한 광소자로서 폴리머 광도파로와 브래그 격자를 이용하는 구조를 최초로 제안하였다. 유효굴절률법과 전송행렬법을 이용하여 최적의 감도를 가지는 브래그 격자 광도파로를 설계하였으며 코아와 하부 클래딩의 굴절률이 각각 1.540, 1.430인 폴리머를 이용하여 코아 두께가 $3{\mu}m$ 인 구조의 반전립 광도파로를 제작하였다. 코아 층까지 완성된 도파로 위에 레이저 빔 간섭계와 플라즈마 에칭을 이용하여 격자를 형성한 뒤 격자표면에 20 nm 두께의 Au층을 증착하고 칼릭사린(calixarene) 단분자층을 만들어 바이오센서를 제작하였다. 제작된 광센서를 이용하여 PBS(phosphate bufferedsaline) 용액에 함유된 $K^+$의 농도에 따라 브래그 반사픽이 단파장으로 이동하는 것을 관찰할 수 있었다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권1호
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• pp.6-10
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• 2001

In this study, we investigated the optical properties of sub-wavelength a-Si thin film transmission gratings, especially the polarization effect, the phase difference and the birefringence by using linearly polarized He-Ne laser beam (632.8nm). The a-Si transmission grating of the thickness $of < 0.1 \mum$ with four-type period($\Lambda = 0.4 \mum and 0.6 \mum$ for sub-wavelength and $\Lambda = 1.0 \mum and 1.4 \mum$ for above-wavelength) on quartz substrates have been fabricated using 50 KeV Ga+ Focused-Ion-Beam(FIB) Milling and $CF_4$Reactive-Ion-Etching(RIE) method. Finally, we obtained the trating array of a-Si thin film with a period $0.4 \mum, 0.6 \mum, 1.0 \mum, 1.4 \mum$ which have nearly equal finger spacing and width, sucessfully. Especially, for gratings with $\Lambda = 0.6 \mum(linewidth=0.25 \mum, linespace=0.35\mum), the \etamax at \theta_в=17.0^{\circ}$ is estimated to be 96%. As the results, we believe that the sub-wavelength grating arrayed a-Si thin film has the applicability as the optical device and components.

• Korea-Australia Rheology Journal
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• 제17권3호
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• pp.117-123
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• 2005

Background: Reduced deformability of red blood cells (RBCs) may play an important role on the pathogenesis of chronic vascular complications of diabetes mellitus. However, available techniques for measuring RBC deformability often require washing process after each measurement, which is not optimal for day­to-day clinical use at point of care. The objectives of the present study are to develop a device and to delineate the correlation of impaired RBC deformability with diabetic nephropathy. Methods: We developed a disposable ektacytometry to measure RBC deformability, which adopted a laser diffraction technique and slit rheometry. The essential features of this design are its simplicity (ease of operation and no moving parts) and a disposable element which is in contact with the blood sample. We studied adult diabetic patients divided into three groups according to diabetic complications. Group I comprised 57 diabetic patients with normal renal function. Group II comprised 26 diabetic patients with chronic renal failure (CRF). Group III consisted of 30 diabetic subjects with end-stage renal disease (ESRD) on hemo-dialysis. According to the renal function for the diabetic groups, matched non-diabetic groups were served as control. Results: We found substantially impaired red blood cell deformability in those with normal renal function (group I) compared to non-diabetic control (P = 0.0005). As renal function decreases, an increased impairment in RBC deformability was found. Diabetic patients with chronic renal failure (group II) when compared to non-diabetic controls (CRF) had an apparently greater impairment in RBC deformability (P = 0.07). The non-diabetic cohort (CRF), on the other hand, manifested significant impairment in red blood cell deformability compared to healthy: control (P = 0.0001). Conclusions: The newly developed slit ektacytometer can measure the RBC deformability with ease and accuracy. In addition, progressive impairment in cell deformability is associated with renal function loss in all patients regardless of the presence or absence of diabetes. In diabetic patients, early impairment in RBC deformability appears in patients with normal renal function.

• Korean Journal of Acupuncture
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• 제33권1호
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• pp.1-11
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• 2016

Objectives : When we understand the characters of certain person or object, we try to follow each one's or its past up. Korean Journal of Acupuncture is one of the most significant journal in acupuncture study fields in Korea. To understand the trends of study in acupuncture study fields, I made a subject with Korean Journal of Acupuncture. Methods : I made an evaluation and classification for all 713 articles' headline from vol. 17(2000 year) to vol.32(2015 year). Results : 1. Experimental Reseach : There were major portion articles for pharmaco-acupuncture study out of studies for acupuncture, moxibustion, chiropratics, devices and so on. 2. Bibliographical Research and Basic Theory Research : There were major portion articles for medians and acu-point study out of studies for article review and text book itself. Also, there were major portion articles for meridian and acupuncture study out of studies for Qigong, pulse, anatomy and so on. 3. Clinical Research : There were major portion articles for acupuncture study out of studies for moxibustion, chiropratics, devices, complex treatments and so on. 4. Others : There were major portion articles for diagnosis and measurement devices out of acupuncture, laser, pulsing device and so on. Also, there were surveys for recognition of patients and medical services and evaluations for measuring diagnosis utility and those effects. Conclusions : With thise results, I hope that several researchers could consider scope and subject when they submit articles for Korean Journal of Acupuncture.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.183-183
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• 2011

Multiferroic materials have been widely studied in recent years, because of their abundant physics and potential applications in the sensors, data storage, and spintronics. $BiFeO_3$ is one of the well-known single-phase multiferroic materials with $ABO_3$ structure and G-type antiferromagnetic behavior below the Neel temperature $T_N$ ~ 643 K, but the ferroelectric behavior below the Curie temperature $T_c$~1,103 K. In this study, the $BiFe_{1-x}Ni_xO_3$ (x=0 and 0.05) bulk ceramics were prepared by solid-state reaction and rapid sintering with high-purity $Bi_2O_32$, $Fe_3O_4$ and NiO powders. The powders of stoichiometric proportions were mixed, as in the previous investigations, and calcined at 450$^{\circ}C$ for $BiFe_{1-x}Ni_xO_3$ for 24 h. The obtained powders were grinded, and pressed into 5-mm-thick disks of 1/2-inch diameter. The disks were directly put into the oven, which has been heated up to 800$^{\circ}C$ and sintered in air for 20 min. The sintered disks were taken out from the oven and cooled to room temperature within several min. The phase of samples was checked at room temperature by powder x-ray diffraction using a Rigaku Miniflex diffractometer with Cu K${\alpha}$ radiation. The Raman measurements were carried out by employing a hand-made Raman spectrometer with 514.5-nm-excitation $Ar^+$ laser source under air ambient condition on a focused area of 1-${\mu}m$ diameter. The field-dependent magnetization measurements were performed with a superconducting quantum-interference-device magnetometer.

• 로봇학회논문지
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• 제8권1호
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• pp.29-36
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• 2013

This paper presents a sensitivity optimization of a MEMS (microelectromechanical systems) gyroscope for a magnet-gyro system. The magnet-gyro system, which is a guidance system for a AGV (automatic or automated guided vehicle), uses a magnet positioning system and a yaw gyroscope. The magnet positioning system measures magnetism of a cylindrical magnet embedded on the floor, and AGV is guided by the motion direction angle calculated with the measured magnetism. If the magnet positioning system does not measure the magnetism, the AGV is guided by using angular velocity measured with the gyroscope. The gyroscope used for the magnet-gyro system is usually MEMS type. Because the MEMS gyroscope is made from the process technology in semiconductor device fabrication, it has small size, low-power and low price. However, the MEMS gyroscope has drift phenomenon caused by noise and calculation error. Precision ADC (analog to digital converter) and accurate sensitivity are needed to minimize the drift phenomenon. Therefore, this paper proposes the method of the sensitivity optimization of the MEMS gyroscope using DEAS (dynamic encoding algorithm for searches). For experiment, we used the AGV mounted with a laser navigation system which is able to measure accurate position of the AGV and compared result by the sensitivity value calculated by the proposed method with result by the sensitivity in specification of the MEMS gyroscope. In experimental results, we verified that the sensitivity value through the proposed method can calculate more accurate motion direction angle of the AGV.

• 한국통신학회논문지
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• 제35권12B호
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• pp.1236-1243
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• 2010

광통신 네트워크 유지보수에 사용되는 광섬유 선로 감시 장치인 OTDR 방식으로 구성된 광섬유 센서장치를 이용하여 광섬유 외곽 경비 시스템을 제작하고 특성을 평가하였다. OTDR 하나로 400m의 광 펜스를 감지하기 위하여 중심파장은 1310nm이며, 출력전력이 +15dBm인 펄스 레이저를 사용하였다. MPU 보드에 고속의 32비트 프로세서인 S3C2440을 탑재하여 알고리즘 처리에 따른 성능 향상을 도모하였다. 제작결과 최대 오차는 최대거리인 10km 구간 시험에서 0.84m이었고, 모든 구간에서 합격기준인 ${\pm}1m$를 만족하였다. 광 펜스 이상 감지 후 경보시간은 3초 이내로 확인하였다. 1차 침입 후에 2차 침입이 발생했을 경우 이를 효과적으로 감시하기 위한 2차 침입감지와 다중점 측정을 위하여 광스위치를 OTDR안에 내장시켰다. 광스위치를 이용하여 효과적으로 2차 침입감지와 다중점 측정이 가능함을 보였다.

• 한국광학회지
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• 제18권6호
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• pp.441-446
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• 2007

OLED 소자는 유리기판과 공기 층의 경계면에서 발생하는 전반사와 ITO-유기층으로 형성되는 광도파로를 따라 진행하는 도파모드 결합으로 인해 내부에서 생성된 빛의 80% 이상이 외부로 추출되지 못하게 된다. 본 연구에서는 마이크로 렌즈 어레이와 회절격자 레지스트 층을 이용하여 소자 내부에서 손실되는 빛을 외부로 추출시킴으로써 OLED의 발광효율을 향상시킨다. 마이크로 렌즈 어레이를 이용하여 유리기판-공기 전반사로 인해 내부에 갇히는 빛을 외부로 출력시키고, ITO 와 유기물 사이에 회절격자 레지스트 층을 삽입하여 ITO-유기층 광도파로에 갇힌 빛들을 수직방향으로 추출될 수 있도록 하였다. 제작된 OLED 소자에 전류밀도 $20mA/cm^2$를 인가한 경우, 마이크로 렌즈 어레이를 적용한 OLED에서 22%의 효율 개선을 얻었고, 회절격자 레지스트 층을 가지는 OLED 의 경우 41%의 효율개선을 얻을 수 있었다.

• 대한공간정보학회지
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• 제10권3호
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• pp.89-97
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• 2002

45(GNSS, SIIS, GIS, ITS) 기술의 핵심이 되는 공간정보의 상호 공유 극대화를 위하여 원격지 공간 데이터 공유 및 제공을 위하여 45-Van 시스템을 개발해오고 있다. 45-Van 시스템은 GPS/IMU, 레이저, CCD 영상, 무선통신기술을 통합 연계하여 현장에서 GIS용 DB 정보 등과 같은 45 핵심 DB정보 및 정확한 위치 정보를 직접 획득 생산이 가능하다. 즉, 4S-Van은 GPS와 IMU의 통합으로 카메라의 위치 및 자세를 결정하며, 두 대의 CCD카메라로 전방을 촬영하여, 공간전방 교회법(Space Intersection)으로 피사체의 위치해석을 하게 되고 기존의 벡터 DB 체계와 호환됨으로써 데이터베이스의 구축 및 현장활용이 가능하도록 할 수 있는 기술이다. 또한 적외선 카메라 및 무선 통신 기술을 활용한 다양한 응용이 가능하다. 본 논문에서는 GPS, CCD 카메라, IMU의 차량 탑재에 의한 45-Van 설계와 기능에 대하여 살펴본다.

• Physical Therapy Rehabilitation Science
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• 제4권1호
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• pp.49-54
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• 2015

Objective: Cervical stabilization exercises are frequently to improve strength and endurance of cervical muscles. The purpose of this study was to identify changes in head repositioning accuracy (HRA) and neck proprioception through cervical stabilization exercises in healthy adults. Design: One group pretest-posttest design. Methods: Thirteen participants with no previous history of neck pain or injury to the cervical spine were recruited. HRA was measured by equipment including laser pointer, helmet, eye patch and marking pens. The distance between the spot where the beam had stopped and the center of the graph paper was measured three times with the averaged value used as the head repositioning accuracy. Neck proprioception was measured by a cervical range of motion device (CROM). Subjects wore the CROM tester and were to look straight ahead while bending his/her neck. Subjects were instructed to perform extension, lateral flexion and rotation, and the values were then measured and recorded. The measurements were performed pre-intervention, and after cervical stabilization exercise. Results: There was no significant difference on HRA after intervention. In addition, there was no significant difference on neck proprioception compared with pre-intervention. Conclusions: The present study did not identify any effect on HRA and neck proprioception of cervical stabilization exercise. Further investigations are required to elucidate this in old aged participants and patients with neck pain.