WDM 광소자 제작을 위한 S-Bend형 방향성 결합기 설계에 관한 연구

라경태,윤중현,김상덕,최현용,김종빈 조선대학교 전자정보통신연구소 2001 電子情報通信硏究所論文誌 Vol.4 No.2

In this paper, we proposed a waveguide offset-applied S-Bend type directional coupler for reducing loss and complete coupling. Calculation results were gained by effective index method and simulated by beam propagation method. Condition for calculation are as follows. Refractive index difference between core and clad is 0.75%, clad index is 1.444, waveguide separation is 3 ㎛, and curvature radious is 10000 ㎛. As results from simulation, 3 dB coupler and full coupling directional coupler have to introduce a waveguide offset 0.25 ㎛ for minimum insertion loss and complete coupling, and we certificated that waveguide offset affected to insertion loss properties. Hence, we found that a directional coupler for wavelength division (de)multiplexing has to introduce a proper waveguide offset.

채널간 파장간격 Δλ=2nm인 4채널 WDM 광소자 설계 및 특성에 관한 연구

라경태,김필중,윤중현,김상덕,김종빈 조선대학교 전자정보통신연구소 2000 電子情報通信硏究所論文誌 Vol.3 No.1

WDM/FDM is expected to be a basic technology for constructing cost-effectively high-speed and large capacity optical networks in the future, device technologies for supporting WDM/FDM function have begun to be studied actively In this paper, we proposed a 4 channel WDM optical device and simulated it based on Mach-Zehnder Interferometer with channel spacing Δλ=2nm at central wavelength λ =1 55㎛. So, we assumed initial condition that core dimension, 6㎛×6㎛, core index, 1 455, clad index, 1 444 at wavelength 1 55㎛, and the separation between channel waveguides, 4㎛ From this condition, we analyzed a channel waveguide and optical coupler(3㏈ coupler), simulated a single Mach-Zehnder Interferometer, and then designed a 4 channel WDM

닷넷 기반 분석 애플리케이션 성능 향상에 관한 연구 : 웹 기반 중심 Web Based

손경덕,김화종 강원대학교 정보통신연구소 2005 정보통신논문지 Vol.9 No.-

.NET is the fastest-growing development platform in the world. ASP.NET powers some of the biggest web sites and applications. This paper provides end-to-end guidance for managing performance and deep platform knowledge across the .NET Framework technologies. This paper introduces common issues of performance and proposes coding techniques to improve the performance of ASP.NET pages and controls, ADO.NET, and Enterprise Services(COM+). Our performance study shows that these techniques are faster than general programming techniques.

WDM 광소자 개발을 위한 점정합법에 의한 사각형 광도파로 해석

라경태,김상덕,김종빈 조선대학교 에너지.자원신기술연구소 1999 에너지·자원신기술연구소 논문지 Vol.21 No.1

This paper describes a point matching method that is based on an expansion of the electromagnetic field in terms of a series of Bessel and modified Bessel functions multiplied by trigonometric functions. In this method, the electric and magnetic fields inside the waveguide core are matched to those outside the core a t matching points on the boundary to yield matrix equations. The paper presents the results of the computation in the form of curves of the propagation constants. The propagation curves are presented in a form of refractive index independent. Also, the paper presents a energy distribution of various modes relative inside the core to outside the core. As a result of this analysis, we are certain that a point matching method can be used usefully for the analysis of optical device such as multichannel optical filter, optical splitter and combiner, high density FDM/WDM device and etc., based on rectangular optical waveguide whether refractive index difference is large or not.

3관능성 BPA-3MA를 기질로한 광중합형 치면열구전색재의 물성 연구

박경준,김경남,안광덕,김광만,한동근,전호욱 대한치과기재학회 1998 대한치과재료학회지 Vol.25 No.2

The BPA-3MA(bisphenol-A trimethacrylate) in which one of two hydroxy group was substituted by methacrylate was synthesized by reaction of Bis-GMA with methacryloyl chloride. To investigate the possibility to apply BPA-3MA as matrix of composite resin or pit and fissure sealant, BPA-3MA(3MA) or Bis-GMA(GMA) as matrix, TEGDMA as diluent, CQ as photosensitizer, EDMAB as photoinitiator and 5㎛ pyrogenic silica as filler were used for making experimental sealants. In addition, these experimental sealants were compared to a commercial Concise L/C White sealant(CLW, 3M Co, U.S.A.) for flexural strength, diametral tensile strength, amount of abrasion, surface hardness, water sorption and solubility, and degree of conversion. The flexural strength of CLW was the highest value but there was not significant difference with 3MA. Diametral tensile strength of all 3 groups were similar(p>0.05) and the amounts of abrasion of 3MA and GMA were less than that of CLW(p<0.05). The surface hardness of 3MA was higher than that of GMA(p<0.05) but similar to that of CLW. The water sorption of 3MA was less than that of GMA and CLW(p<0.05) and the solubilities of 3MA and CLW were than that of GMA(p<0.05). GMA and CLW were relatively polymerized well as compared to 3MA. From these results, pit and fissure sealant using trifunctional BPA-3MA as matrix had superior physical and mechanical properties to existing Bis-GMA sealant. Furthermore, it will be possible to develop composite resin having superior properties to existing composite resin.

수술중 수혈환자에 대한 임상적 고찰(Ⅲ)

최세진,서경덕,조희경 충남대학교 의과대학 지역사회의학연구소 1992 충남의대잡지 Vol.19 No.2

Over the Past several decades blood and blood components have been increasingly, recognized as medication rather than innocuous fluids used to replace modest blood lose at operation. But blood transfusions have the potential for many harmful side effects. This study was undertaken to evaluate transfusion accordings to department, sex, preoperative hemoglobin values, blood type, transfusion amounts and blood component therapy. Of a total 34.906 operative cases, 5,793 patients who recived a transfusion during operation were analyze statistically at the Department of anesthesiology, chungnam National University Hospital from January 1985 to September 1992. The results were as Follows : 1) The numbers of transfused patient among the 34,906 operative cases were 5,793 cases (16.57%). 2) The number of male transfused was greater than of female and third decade patients was the greatest incidence among the transfused patients. 3) Mostly hemoglobin value in preoperative state was maintained more than 10 mg/dl (85.75%). 4) The blood types of transfused blood were in the great order of A, B, O, AB type. 5) The percentage of one pint transfusion was gradually decreased and 2~5 pints transfusion was greatest percentage (60.11%). 6) As the amount of blood transfused was increased, the percentage of blood component therapy was increased, and mixed case PRC and FFP was the greatest incidence (46.02%).

판막 질환에서의 심근 섬유화 : 심근 조직을 이용한 형태학적 연구 및 혈청 생화학적 지표의 분석

강수진,박덕우,송재관,박경민,송종민,강덕현,한기훈,송현,이재원,주석중,송명근,김정선 대한순환기학회 2004 Korean Circulation Journal Vol.34 No.2

신경계 질환 환자에 대한 영양보충제 '뉴케어'의 임상적 효과

김용재,박기덕,최경규 梨花女子大學校 醫科大學 醫科學硏究所 1997 EMJ (Ewha medical journal) Vol.20 No.2

연구목적: 질병의 경과에 미치는 영양상태의 중요성은 이미 알려져 있지만, 임상의사가 직접 환자를 대할 때는 영향 결핍 상태를 흔히 간과하게 된다. 본 연구는 연하곤란으로 영양불량 상태에 있는 신경계 질환 환자군에서 영양보충제인 뉴케어를 경구 투여하였을 때, 환자의 질병 회복과 영양상태의 개선에 미치는 임상적 효과를 평가 하고자 하였다. 연구방법: 뇌졸중, 뇌출혈, 노인성 치매 등의 신경계 질환으로 연하장애 상태에 있는 환자들을 대상으로 하여 영양보충제인 뉴케어를 투여한 후 혈액학적, 혈액화학적 변화와 주관적 부작용 등을 평가하였다. 결 과: 연구에 사용한 여러 척도 가운데 혈장 알부민치와 영양지수의 변화가 유의하게 나타났다. 뉴케어를 투여한 군에서 혈장 알부민이 전ㆍ후 각각 44.6 48.2로 전ㆍ후 각각 44.6, 44.1를 보인 대조군에 비해 유의한 증가를 보였다.(p<0.05). 몇 몇에서 설사가 나타나기도 하였으나 투여를 중단할 만한 뚜렷한 부작용은 관찰되지 않았다. 결 론: 이상으로 신경계 질환 환자에서 뉴케어는 혈청 알부민과 영양지수의 증가를 일으켰으며, 안전하고 효율적인 영양보충제로 생각된다. Patients suffering from neurological disorder, such as cerebral infarctoin, often face serious swallowing difficulty and malnutrion. Although the importance of nutritional support has been well demonstrated, malnutrition remains a frequently neglected condition in the clinical setting. In this study, we investigate the effectiveness of enteral nutritional support to neurological patients using nutritional beverage Nucare. 50 patients with acute and chronic neurological disease with eating problem were participated. 27 patients(experimental group : 17, control group :7), fed more than 7 days, were selected and statically analyzed by the changes of hematologic, biochemical parameters and nutritional index compared with control roup(p<0.05), which are good predictors of nutritional and hospital outcome. This suggests that enteral nutritional support with Nucare can improve the nutritional status and clinical outcome of patient with acute and chronic neurological disease.

열공형과 비열공형 피질하 혈관성 치매에서 위험인자의 차이에 관한 비교 연구

배희준,정지향,유경호,나덕렬,김상윤,최경규,양동원,손의주,이상도,김재우,박경원,김응규,이재홍,박미영,한일우,함동석,최문성,하충건,최성혜,이애영,이병철,한설희 대한치매학회 2003 Dementia and Neurocognitive Disorders Vol.2 No.2

Backgrounds and Objectives: Vascular dementia is a group of dementing disoders arising from various stroke syndrome. Among these. subcortical ischemic vascular dementia (SIVD) is regarded as a relatively distinct clinical entity. However, MRI patterns of SIVD are not homogenous. In some patients, lacunes are dominant, and in others, subcortical white matter changes are. This study was designed to compare risk factor profiles between SIVD with and without multiple lacunes. Methods: We divided 47 subjects (22 males, mean age. 68 years) recruited from VADAPET (Multicenter Trial For Evaluation Of The Changes In the PET Images Of Subcortical Vascular Dementia Patient) study into two groups one with more than 5 lacunes in deep gray matter (lacune group) and the other with 5 or less(non-lacune group) Clinical characteristics and laboratory findings of two groups were compared. Results: Nineteen of 47 patients (40%) belonged to the lacune group. The lacune and non-lacune groups d d not differ in the following variables: age, hypertension, diabetes mellitus, hyperlipidemia heart disease, history of stroke or TIA, history of trauma or major surgery, family history of hypertension stroke, or dementia, age at diagnosis of dementia, body mass index, white blood cell count, ESR, CRP, fibrinogen, hemoglobin A1C, total cholesterol. LDL cholesterol creatinine, proteinuria, glucosuria, and microhematuria. However, male sex, smoking alcohol. hemoglobin, and HDL cholesterol were possibly associated more with lacune group SIVD than with non-lacune group (p<0 1) Multivariate analyses revealed that smoking, hemoglobin, and HDL cholesterol were independent predictors of SIVD with multiple lacunes Conclusion: Our study suggests that SIVD with multiple lacunes may be significantly different in smoking habits hemoglobin, and HDL cholesterol from SIVD without multiple lacunes.

분광 엘립소메트리의 응용을 위한 0차 Retardation Plate의 Alignment

이용달,박명규,김세덕,방경윤,안일신 한양대학교 이학기술연구소 2000 이학기술연구지 Vol.2 No.

A zero-order retarder was fabricated using two pieces of magnesium fluoride plates. In order to achieve desired zero-order retardation for specific wavelength, both the thickness of plates and the alignment of two fast axes were very important. We found that the alignment should be checked using broad band detection system for spectroscopic application, We devised alignment method by which the two fast axes lie perpendicularly to each other. The periodic oscillation feature in retardation angle versus wavelength disappeared with good alignment. We also developed calibration method to deduce the retardation angle over a wider spectral range using rotating compensator ellipsometer. 두 조각의 마그네슘 플로라이드 판을 이용한 0차 retarder를 제작하였다. 특정한 파장에 대하여 원하는 0차 retardation을 얻기 위해서는 판의 두께와 alignment가 매우 중요하였다. 분광학적인 응용을 위해서는 넓은 파장 영역을 측정할 수 있는 detection system의 사용이 필요하였다. 이를 이용하여 두 판의 fast axes가 서로 수직으로 놓이게 할 수 있는 alignment 방법을 개발하였다. 파장에 대한 retardation 각도에서의 주기적인 진동의 모양은 alignment를 잘하게 되면 사라지게 된다. 또한 rotating compensator ellipsometer를 사용 할 때 넓은 분광영역에 걸친 retardation angle을 측정해 낼 수 있는 calibration 방법을 개발하였다.