http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
미주신경 전기자극이 심박변이도와 스트레스호르몬 분비에 미치는 효과 - 파일럿 연구
문현주 ( Moon Hyunju ),조성학 ( Cho Sunghak ) 대한통합의학회 2018 대한통합의학회지 Vol.6 No.3
Purpose: Stress tends to cause sympathetic hyperactivity and increase blood cortisol levels. The vagus nerve is a parasympathetic nerve that is involved in relaxing the body. The purpose of this study was to investigate the effects of electrical stimulation of the vagus nerve on stress hormone (cortisol) levels and heart rate variability (HRV) in humans. Methods: A total of 10 healthy subjects participated in the pilot experiment. All subjects underwent electrical vagus nerve stimulation for 20 minutes in the cymba conchae of the left ear. An electro cardiogram meter was used to measure HRV. Blood samples were collected and analyzed for cortisol levels. The standard deviation of all normal N-N intervals (SDNN), root mean square of successive differences (RMSSD), low frequency, high frequency, and cortisol levels were compared in pre and post mean values after the intervention. Data were analyzed using the Wilcoxon’s signed-rank test. Results: Coritsol levels were observed to decrease after vagus nerve electrical stimulation. The mean SDNN and RMSSD values were increased after the intervention, but not significantly. Conclusion: Vagus nerve electrical stimulation has been shown to increase the ability of the parasympathetic nerve to adapt to upward regulation and stress. Vagus nerve electrical stimulation could thus be an effective treatment for modern social psychological stress control.
김재구(Jaegu Kim),조성학(Sunghak Cho),장원석(Wonseok Chang),나석주(Suck-Joo Na),황경현(Kyunghyun Whang) 한국레이저가공학회 2007 한국레이저가공학회지 Vol.10 No.4
In this paper, we suggested the femtosecond laser processing using the mask which makes Gaussian spatial beam distribution to a normalized distribution by Fresenel diffraction. Holography pattern of the size of 320 × 320 ㎛² on the Cr thin film on glass substrate with a pixel size of 5 × 5 ㎛² was fabricated according to the pattern generated by the iterative Fourier transform algorithm (IFTA) algorithm. We analysed the damage threshold with an assumption the power distribution as Gaussian profile as 45 mJ/㎠, The regenerated image of letters through the diffractive pattern was well recognized at the screen.
민복기(Bokki Min),김재구(Jaegu Kim),조성학(Sunghak Cho),최두선(Doosun Choi),황경현(Kyunghyun Whang) 한국레이저가공학회 2008 한국레이저가공학회 학술대회 논문집 Vol.2008 No.-
This paper presents the method to fabricate a roll mold with microstructure using DPSS(diode pumped solid-states) UV laser. DPSS laser ablation makes it possible to micromachine by controlled energy density and pulse repetition rate of laser. But, In case of metal ablation, molten debris is caused by thermal damage. Hence, We suggest the process of the ablation of a photoresist(PR) coated on roll mold. And we design a roll coater for laminating the photoresist onto the curby surface of a copper roll mold. The microstructure on roll mold is fabricated by controlled laser pulse energy, pulse repetition rate, rotation speed and rotation number of roll. We compare and analyze the quality of microstructure by the wet etching process with the quality by the direct write process.
DPSS UV laser와 습식 식각을 이용한 금형강 미세 가공
민경익(Kyoungik Min),김재구(Jaegu Kim),조성학(Sunghak Cho),최두선(Doosun Choi),황경현(Kyunghyun Whang) 한국레이저가공학회 2009 한국레이저가공학회지 Vol.12 No.3
This paper describes the method for the fabrication of micro dot array on a plastic mold steel using DPSS (diode pumped solid-states) UV laser and wet etching process. We suggest the process of the ablation of a photoresist (PR) coated on plastic mold steel and wet etching process using solutions of various concentrations of FeCl3, HNO3 in water as etchants. This method makes it possible to fabricate metallic roller mold because the microstructures are directly fabricated on the metal surface. In the range of operating conditions studied, 17 μJ laser pulse energy and 50 ms laser exposure time, an etchant containing 40wt% FeCl3, 5wt% HNO3 and etch time for 45 s gave the 10 ㎛ of micro dot pattern on plastic mold steel.
레이저에 의해 패터닝 된 바늘과 탄성중합체와의 마찰 효과
김재구(Jaegu Kim),노승국(Seungkook Ro),박종권(Jongkweon Park),조성학(Sunghak Cho),황경현(Kyunghyun Whang) 한국레이저가공학회 2012 한국레이저가공학회지 Vol.15 No.3
The friction force of patterned needle in elastomer have been investigated to verify the application for bio and plastic industry. The micro pattern on the needle surface were prepared by 266 nm, 20 ns laser and 800 nm, 220 fs laser, which were able to generate the different surface roughness. The friction force was measured by the load cell of 10 N capacity. As the results, the friction force of no patterned needle is almost constant during the needle penetrates the silicone rubber sample. However, the needle having asperities shows the variation of the friction force. The higher the surface roughness is, the smaller the friction force is until the surface roughness is very high. In our experiment conditions, the reduction of the friction force by 20 % compared to no pattern needle was achieved with straight and 50 μm discrete line generated by 266 nm, 20 ns laser.
장원석(Wonseok Chang),최무진(Moojin Choi),김재구(Jaegu Kim),조성학(Sunghak Cho),황경현(Kyunghyun Whang) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
Self-Assembled Monolayers(SAMs) by alkanethiol adsorption to thin metal film are widely being investigated for applications as molecular recognition, selective binding of enzyme to surfaces, coating layer for corrosion protections or friction reduction and in fabrication of micro structure of bio molecular. In this study, standard positive photoresist techniques were adapted to generate micro/nano patterns of gold film using SAMs and femtosecond laser (200fs). SAMs formed by the adsorption of alkanethiols onto gold substrate with 100㎚ thickness are employed as very thin photoresist. We present the fabrication of thin film that has heterostructure of two different kinds of thiol by maskless laser patterning of organic SAMs. And this method also extend to nanoscale patterning using near-field scanning optical microscopy coupled with femtosecond laser.
클로로메틸 폴리이미드(CMPI) 박막과 근접장 나노 프로브 레이저 패터닝을 이용한 미세 형상 가공 기술
최무진(Moo Jin Choi),장원석(Wonseok Chang),김재구(Jaegu Kim),조성학(Sunghak Cho),황경현(Kyunghyun Whang ) 한국정밀공학회 2004 한국정밀공학회 학술발표대회 논문집 Vol.2004 No.10월
Photo-induced surface alignment is charming as a non-contact photo-patternable alignment technology which can be used in the next generation of displays, such as large area, multi-domain. For decades, many polymer film have been investigated and developed to be used in the photo alignment. Among these photoreactive materials, recently developed polyimide, Chloromethylated Polyimide(CMPI) now became the focus of interests in this area because of its high photosensitivity and superior thermal stability. In this report, we present micro patterning method to form the nanoscale structure by Mask-Less laser patterning using this CMPI film and NSOM probe.