고정밀저항용 크롬산화박막의 특성

서정환,노상수,이응안,김광호,Seo, Jeong-Hwan,Noh, Sang-Soo,Lee, Eung-Ahn,Kim, Kwang-ho 한국전기전자재료학회 2005 전기전자재료학회논문지 Vol.18 No.3

This paper presents characteristics of CrOx thin-film, which were deposited on $Al_2$O$_3$ wafer by DC reactive magnetron sputtering in an argon-oxide atmosphere for high temperature applications. The present paper deals with a study of the technological characteristics of thin film resistors to provide a control in obtaining temperature coefficients of resistance of given value. The optimized condition of CrOx thin-film were thickness range of 2500 $\AA$ and annealing condition(350 $^{\circ}C$, 1 hr) in oxide partial pressure(3.5${\times}$10$^{-4}$ torr). Under optimum conditions, the CrOx thin-films is obtained a high resistivity, p=340 $\mu$Ωcm, a low temperature coefficient of resistance, TCR=-55 ppm/$^{\circ}C$. The CrOx thin films resistors which were fabricated in this paper had excellent characteristics as high precision resistors.

유해 혼합기체 실시간 현장 분석을 위한 마이크로 가스 크로마토그래피 시스템 연구

서정환 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.05

척수손상환자에서 Alendronate 복용 후 골밀도의 증가

서정환,이루지,고명환,박성희 대한재활의학회 2005 Annals of Rehabilitation Medicine Vol.29 No.2

Objective: The aim of this study was to investigate the changes of bone mineral density (BMD) according to the postinjury duration, walking ability, and to assess the effect of oral alendronate therapy on BMD and biochemical markers in patients with spinal cord injury. Method: Forty-eight subjects with spinal cord injury were enrolled. One tablet of AlendⓇ (10 mg of sodium alendronate) was administered daily for 6 months. After this, all subjects received placebo for 6 months as the same manner. The baseline quantitative assessments of BMD and biochemical bone markers, serum osteocalcin and C-terminal telopeptide of type I collagen (ICTP), were performed before the administration of drug. The follow up assess-ments were performed at 6 and 12 months after drug and placebo administration. Results: The patients treated with oral alendronate showed significantly higher BMD of femur compared with baseline (p<0.05). Also, ICTP showed significant reduction after alendronate therapy. BMD change rate of alendronate therapy was higher in functional ambulation group compared with wheelchair ambulation group. BMD change rate of alendronate therapy was higher than that of placebo administration. Conclusion: Alendronate therapy may be useful in prevention of loss of BMD after spinal cord injury.

Evaluation of Elbow Stretch Reflex Using a Portable Hand-driven Isokinetic System in Normal Adults

서정환,Soon-Won Yook,송철규,고명환,박성희 대한재활의학회 2011 Annals of Rehabilitation Medicine Vol.35 No.4

Objective To evaluate normal healthy persons without spasticity to observe normal findings of the elbow stretch reflex using a newly developed, portable, hand-driven spasticity-measuring system. Method Thirty normal persons without any disease involving the central or peripheral nervous system were enrolled in this study. The portable hand-driven isokinetic system is able to measure the joint angle, angular velocity, electromyographic (EMG) signals, and torque during elbow passive extension-flexion. One set of 10 passive elbow extension and flexion movements was performed for data acquisition at each angular velocity, including 60, 90, 120, 150 and 180 degrees per second (o/sec). Electromyographic data were collected from the biceps brachii and the triceps brachii. Torque data were collected from sensors around the wrist. Results We were able to detect EMG activity and torque in all subjects by using the new portable hand-driven isokinetic system. EMG activity and torque increased with incremental increase of angular velocities. The joint angle of maximal EMG activity according to different angular velocities did not show any signifi cant difference (116o-127o in elbow extension and 37o-66o in elbow flexion). The joint angles of maximal torque according to different angular velocities were not signifi cantly different either. Conclusion Using the portable hand-driven isokinetic system on the elbows of normal subjects, we were able to obtain expected results. By considering our normal findings of the elbow stretch reflex using this system, we propose that the various aspects of spasticity-related data can be measured successfully.

고온용 압저항센서용 크롬산화박막의 특성

서정환,노상수,이응안,정귀상,김광호 한국센서학회 2005 센서학회지 Vol.14 No.2

This paper present characteristics of chromium oxide thin-film as piezoresistive sensors, which were deposited on Si substrates by DC reactive magnetron sputtering in an argon-Oxide atmosphere for high temperature applications. The chemical composition, physical and electrical properties and thermal stability ranges of the CrOx sensing elements have studied. CrOx thin films with a linear gauge factor(GF≒15), high electrical resistivity(ρ=340μΩ㎝) and TCR〈-55ppm/℃ have been obtained. These CrOx thin films may allow high temperature pressure sensor miniaturization to be achieved.

Fine Mapping and Candidate Gene Analysis of Small Round Grain Mutant in Rice

서정환,Yogendra Bordiya,이찬미,고희종 한국육종학회 2017 Plant Breeding and Biotechnology Vol.5 No.4

Grain size and panicle architecture are important traits determining yield. Here we report a new allele of DEP2 (dense and erect panicle 2) which has a pleiotropic effect on grain size/shape and panicle architecture. A small round grain and erect panicle mutant was obtained by treating japonica cultivar Hwacheong waxy with MNU (N-methyl-N-nitrosourea). Through fine mapping sequence analysis, we identified the single nucleotide substitution in the mutant, which caused splicing error of the first intron, on previously reported DEP2 locus in rice. Since the dep2-1 and dep2-2 have been reported in previous studies, we named this new allele as dep2-3. The dep2-3 mutant manifested reduced grain size and plant height, dense and erect panicle and erect plant architecture. When we crossed the mutant with wild type, panicle and grain of F1 plant showed intermediate phenotype, indicating that dep2-3 showed incomplete dominance, which was not reported in the previous study. Scanning electron microscopy (SEM) results showed that increase in width of mutant grain was due to the increased width of glume cells. Paraffin section of peduncle revealed that outgrowth in outer layer of peduncle compared to inner layer caused the erectness of the panicle. Our results collectively indicated that the dep2-3 might play a significant role in the regulation of grain size/shape and formation of vascular bundles.

훅송과 한국의 대중음악

서정환 대중서사학회 2012 대중서사연구 Vol.- No.27

이 글은 신한류의 중심인 케이 팝에 대해 훅송을 중심으로 살펴보고자 한다. 훅송은 스타시스템에 의해 양산된, 소위 아이돌이라 불리는 걸그룹과 보이그룹에 의해 주로 연행되는 특유의 음악으로 볼 수 있으며음악 형식적인 측면에서는 극단적으로 후렴구를 강조하는 서사구조를지닌다. 실제로 우리는 훅송을 후렴구를 강조하는 중독성 있는 상업적인 음악으로 이해하며 사용하고 있다. 일반적으로 훅송은 그것이 지니고 있는 극단성과 단순성으로 인해 비판적으로 인식되기도 하지만 훅송에 대한 체계적 분석은 찾아보기 힘들다. 하지만 훅송의 본질인 훅에 대한 재해석을 시도함으로써 우리는 훅송에 대한 새로운 접근을 유도할 수 있다. 훅은 ‘우리가 어떤 하나의 곡을듣는 순간부터 그 곡에 대해 기억하는 여러 부분들’로 정의될 수 있다. 훅송 역시 훅에 대한 이러한 정의를 참고하여 후렴구를 포함한 음악내·외적인 모든 부분에서 총체적으로 접근할 수 있을 것이다. 훅송은 단순히 후렴구를 강조하는 노래로만은 볼 수 없으며 훅송에서 나타나는반복과 단순성 역시 반드시 부정적으로만은 볼 수 없다. 왜냐하면 반복에 의한 단순성이 결국 음악의 다른 요소들을 이끌어내며 음악의 새로운 지평을 열어줄 수 있는 가능성을 내포하고 있기 때문이다. 훅송에는 기존 음악 양식의 한계에 대한 대중의 욕망이 반영되어 있다. 이것은 또한 이 시대 전체의 사회 현상과 맞물려 있는 것이기도 하다. 훅송에서 나타나는 형식과 서사의 파괴 역시 동일한 맥락에서 파악할 수 있다. 최근의 노래에서 서사적인 의미를 찾는 것은 힘들 수 있지만 이러한 무의미성을 의미가 없는 것으로 볼 것이 아니라 그 자체로의미 있는 독특한 리듬, 비트를 형성하는 것으로 생각할 수도 있을 것이다. 이것은 가사 대신 다른 음악 요소들을 통해 메시지를 전달하는 것으로 볼 수 있으며 한편으로는 가사를 숨기는 방식, 즉 또 다른 형태의 서사 방식으로 이해할 수 있다. 따라서 훅송은 단순히 전통적인 음악분석관점인 멜로디나 화성의 분석을 넘어 양식적인 측면에 있어 하나의 개성 있는 음악스타일로 인식할 수 있을 것이다. 훅송은 그것의 핵심인 훅으로 대표되는 음악이며 한편으로는 요소요소에 훅들이 숨겨져 있는 음악으로 볼 수도 있다. 비록 이 음악 양식이 현 시점에서 비난받을 수 있을지 몰라도 한국의 대중음악 전반에 중요한 영향을 끼치고 있음을 부인할 수 없을 것이다. 따라서 훅송은 이 시대를 대표하는 하나의 양식으로 재평가될 필요가 있다.

보행이상을 보인 환아들에 대한 고찰

서정환,문재호,박윤길,전세일 大韓再活醫學會 1992 Annals of Rehabilitation Medicine Vol.16 No.2

초음파 센서 기반의 선외기 방향 제어 시스템 구현

서정환,김장원,정동원 한국정보기술학회 2019 Proceedings of KIIT Conference Vol.2019 No.11

Medical chilling device designed for hypothermic hydration graft storage system: Design, thermohydrodynamic modeling, and preliminary testing

서정환 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.2

Hypothermic hydration graft storage is essential to reduce the metabolic demand of cells in vitro. The alleviated metabolic demandsreduce the emergence rate of anaerobic metabolism generating adenosine triphosphate (ATP) energy that creates free radicals. The excessivefree radicals can damage cells and tissues due to their highly oxidative power with molecules. Current cooling systems such as aconventional air cooling system and an ice pack system are inappropriate for chilling cell tissues in vitro because of inconvenience in useand inconsistent temperature sustainability caused by large size and progressive melting, respectively. Here, we develop a medical chillingdevice (MCD) for hypothermic hydration graft storage based on thermo-hydrodynamic modeling and thermal electric cooling technology. Our analysis of obtained hydrodynamic thermal behavior of the MCD revealed that the hypothermic condition of 4°C was continuouslymaintained, which increased the survival rates of cells in vitro test by reduced free radicals. The validated performance of theMCD promises future development of an optimal hypothermic hydration graft storage system designed for clinical use.