CT performance phantom을 이용한 cone beam형 전산화단층영상의 특성

한충완,김규태,최용석,황의환 대한구강악안면방사선학회 2007 Imaging Science in Dentistry Vol.37 No.3

Purpose : To evaluate the characteristics of (widely used) cone beam computed tomography (CBCT) images. Materials and Methods : Images were obtained with CT performance phantoms (The American Association of Physicists in Medicine; AAPM). CT phantom as the destination by using PSR 9000N™ dental CT system (Asahi Roentgen Ind. Co., Ltd., Japan) and i-CAT CBCT (Imaging Science International Inc., USA) that have different kinds of detectors and field of view, and compared these images with the CT number for linear attenuation, contrast resolution, and spatial resolution. Results : CT number of both PSR 9000N™ dental CT system and i-CAT CBCT did not conform to the base value of CT performance phantom. The contrast of i-CAT CBCT is higher than that of PSR 9000N™ dental CT system. Both contrasts were increased according to thickness of cross section. Spatial resolution and shapes of reappearance was possible up to 0.6 mm in PSR 9000N™ dental CT system and up to 1.0 mm in i-CAT CBCT. Low contrast resolution in region of low contrast sensitivity revealed low level at PSR 9000N™ dental CT system and i-CAT CBCT. Conclusion : CBCT images revealed higher spatial resolution, however, contrast resolution in region of low contrast sensitivity was the inferiority of image characteristics.

五加皮의 效能에 대한 硏究

최민호,이계복,조규원,박진영,김경수,송정석,한종현 한국전통의학연구소 2003 한국전통의학지 Vol.13 No.1

The purpose of this study is to measure the changes of regional cerebral blood flow (rCBF) and blood pressure (BP) of Cortex Acanthopanacis in rats, and to determine the effect of Cortex Acanthopanacis on phenylephrine (PE) induced contraction of isolated rat thoracic aorts. The measurement was continually monitored by laser-doppler flowmeter (Transonic Instrument, USA) and pressure transducer (Grass, USA) in anesthetized adult Sprague-Dawley rats through the data acquisition system composed of MacLab and Macintosh computer. Contractile force was measured with force displacement transducer under 1.5 g loading tension. The result of this experiment was as following; 1. Cortex Acanthopanacis did not effect the changes of rCBF and blood pressure significantly. 2. Contractions evoked by phenylephrine were decreased significantly by Cortex Acanthopanacis 3. L-NNA, ODQ, atropine and indomethacin significantly altered the relaxation of Cortex Acanthopanacis. 4. Propranolol did not change the relaxation of Cortex Acanthopanacis. These results indicate that Cortex Acanthopanacis did not change the rCBF and BP, but Cortex Acanthopanacis can relax PE induced contraction of isolated rat thoracic aorta and that this increasing contraction related to endothelium and various mechanism.

델타변조방식을 이용한 전류형 능동필터의 PWM 신호 발생

김한성,김홍성,최규하,신우석 建國大學校 附設 産業技術硏究所 1993 논문집 Vol.18 No.-

The Delta-Modulation(DM) techniques have been used up to now for both UPS and AC motor drives, which have the advantages of simple circuit, fast response, and insensitivity to load variation and other disturbances. In this paper, the DM techniques are adopted to obtain PWM control signals for active power filters. In the design of delta modluator, the decision of break frequency is the most important, particularly for active power filter application. Both digital simulation and simple experiment are performed to investigate the characteristics of the delta modulator proposed.

개선된 리커런트 신경망을 이용한 등화기

박정규,서동신,최한고 國立金烏工科大學校附設生産技術硏究所 1997 産業技術開發硏究 Vol.13 No.-

An adaptive equalizer in digital communication has been used to reduce intersymbol interference(ISI) and noise via radio and telephone channels. The problem of equalization can be viewed as a classification problem, which seeks to classify an observed channel output into one of the finite symbol points in the data. This paper presents the nonlinear adaptive equalizer using the modified recurrent neural networks(RNNs). The RNN structure used in this paper differs from Jordan's and Elman's RNNs with respect to feedback paths. Comparing with the conventional LMS and the feedforward neural network equalizers, the results of the RNN based equalizer show superier performance in terms of mean square error.

韓國南海岸에서의 設計波의 決定

金泰麟,崔漢圭 江原大學校 附設 環境硏究所 1990 環境硏究 Vol.7 No.-

南海 沿岸 地上測後所의 過去風速資料와 麟風 記錄으로 부터 過去의 波浪 資料를 推算(Hindcast-ing)하고 이로부터 얻어진 地域別 波向別 年間 最大波浪의 極植 系列로 부터 確率分析을 通하여 深海 設計波를 決定하는 方法이 提案되었다. 南海 沿岸에 來襲하는 큰 波浪은 麟風과 春夏李 李節風에 의해 生成되며 地域別 波向別로 상당한 差異를 보인다. 再現其間이 100年인 設計 有意波의 波高는 深海에서 4.6m~8.8m, 週期는 8.2sec~12.9sec의 範圍 For determination of the design waves at the seven selected sites in the South Sea, a method of hindcasting the past annual largest significant waves from the records of both the sind speed at the nearby weather stations and the weather charts of typhoons are utilized. The design signifi-cant waves in deep water are determined through the extremal probability analysis for three ma-jor wave directions(SW.S.SE) at each site from the annual extremal series of wave heights. Design significant wave height with the return period of 100 years ranged between 4.6m and 8.8m, with the wave period ranging between 8.2 seconds and 12.9 seconds. Through the analysis of weather maps, both the fetches for the wind directions SW-SE along the South Coast and the relationship between the wind speed at sea and the wind speed at the nearby land weather sta-tions for seasonal winds are determined. The wind speed at sea are found to be 0.8-0.9 times the wind speed at the land stations for U_(L)>15㎧. The ratio of the duration-averaged wind speed to the maximum wind speed varies between 0.7-0.9 as a negative exponential fuction for the dura-tion ranging 2<t<13 hours.

한국산 감잎의 Polyphenol 화합물의 생리활성물질의 화학구조 및 효소저해효과

안봉전,최희진,손준호,우희섭,한호석,박정혜,손규목,최청 한국식생활문화학회 2003 韓國食生活文化學會誌 Vol.18 No.5

The lyophilization of the solution extracted from 60 percent of acetone applied to persimmon leaves, the compounding process in accordance with the solution's concentration, and the gel filteration through Sephadex G-50 of biologically activated substances obstructing enzyme activity, such as tyrosinase, xanthine oxidase, and angiotesin converting enzyme (ACE) led to the assumption that polyphenol was the compound serving as biologically activated substances obstructing enzyme activity. Xanthine oxidase involved in pruine metabolism oxidizes hypoxanthine to xanthine and xanthine to uric acid. In the continuous study for natural compound, nine flavan-3-ois have been isolated from the persimmon leaves. The structures of (+)-catechin, (+)-gallocatechin, procyanidin B-1, pyrocyanidin C-1, prodelphinidin B-3, gallocatechin-(4α→8)-catechin, procyanidin B-7-3-O-gallate, procyanidin C-1-3'-3''-3'''-O-trigallate and (-)-epigallocatechin-(4β→8)-epigallocatechin-(4β→8)-catechin were established by NMR and their inhibitory effect on xanthine oxidase activity was investigated. Procyanidin C-1-3'-3''-3'''-O-trigallate showed 94%, 90.69%, 80.90% inhibition at 100(μ)M and inhibited on the angiotension converting enzyme respectively. Procyanidin B-7-3-O-gallate and procyanidin 1-3'-3''-3'''-O-trigallate showed 66%, 63% inhibition at 100(μ)M and inhibited on the xanthine oxidase competitively. Procyanidin C-1-3'-3''-3'''-O-trigallate showed 70% inhibition at 100(μ)M inhibited on the thyrosinase competitively.

미생물 성장 특성에 기초한 독립영양탈질의 화학양론식 연구

이수원,김규동,최영균,김동한,정태학 대한상하수도학회 2004 상하수도학회지 Vol.18 No.2

It is necessary to supply external carbon source for enhancement of biological nitrogen removal from domestic wastewater with low influent C/N ratio. Sulfide was chosen as a cost effective electron donor and reaction stoichiometry for autotrophic denitrification was investigated by conducting bench-scale experiments in this study. Higher sulfur to nitrogen (S/N) ratio than the calculated value from theoretical reaction stoichiometry was required when the anoxic reactor was operated at open condition because dissolved oxygen introduced by surface aeration reacted with sulfide with ease. In addition, higher sulfate production and lower yield of microorganism could be observed under the same condition. It was possible to obtain reliable reaction stoichiometry for autotrophic denitrification by establishing pure anoxic condition. Linear relationship between bacterial growth and consumption of nitrate, sulfide, alkalinity, and sulfate production enabled to derive a relatively correct reaction stoichiometry for autotrophic denitrification when sulfide was used as an electron donor.

글쓰기 교육과 한문 교육의 앞으로의 방향

손병국,오정란,조규일,최기용,한지현 광운대학교 인문사회과학연구소 2000 인문사회과학논문집 Vol.29 No.-

상염색체우성 다낭신의 임상경과 및 합병증

이상주,이영모,이한규,최대은,박기현,이강욱,신영태 충남대학교 의학연구소 2001 충남의대잡지 Vol.28 No.2

Autosomal dominant polycystic kidney disease(ADPKD) is one of most common hereditary disorder. It is potentially fatal and the major mobilities are hypertension and renal failure. To elucidate clinical characteristics and outcomes of ADPKD, 67 ADPKD patients were analyzed retrospectively. The male to female ratio was 48 years for males and 42 years for females. The factors leading to the dignosis of ADPKD were flank or abdominal pain (46%), palpable abdominal mass (24%), incidental findings (18%), gross hematuria and headache. Urinalysis result showed hematuria (31%), proteinuria (19%), pyuria (18%). Among renal complications hypertension (67%) was the most common. Other complications were urolithiasis (16%) upper urinary tract infection (9%), cyst infection (7%). Azotemia was observed in 24% of cases. Echocardiography showed left ventricular hypertrophy in 24% and valvular regurgitation in 18% of cases, but there was no mital valve prolapse. Cerebrovascular events occurred in 6 cases (2 cases of intervertebral hemorrhage and 4 cases of cerebral infarction). Hipatic cyst were observed in 64% of cases. Eighteen cases culminated in end stage renal failure (ESRF) at an of 47. According to this study, the most common complications of ADPKD was hypertension (67%), ESRF (27%), and cerebrovascular event (9%). Hypertension was more frequently observed in increased creatinine group than normal.

Cutaneous Infection by Geotrichum candidum

Choi, Han Gyu,Seo, Seong Jun,Hong, Chang Kwun,Ro, Byung In 대한의진균학회 1999 대한의진균학회지 Vol.4 No.1

Geotrichum candidum은 세계적으로 분포하는 효모균으로 토양과 분변 등에서 발견되고 드물게 면역이 감소된 환자에서 폐감염, 아구창, 설사 등을 일으키는 것으로 알려져 있다. 분절포자 (arthroconidia)를 형성하는 것을 특징으로 하며, 형태학적으로 Coccidioides immitis, Trichosporon beigelii, Blastoschizomyces capitatus와 매우 유사하여 감별을 요한다. 환자는 20세 여자로 내원 7개월 전 등산 중 바위에 의하여 찰과상을 받은 일주일 후 발생한 좌측전경골부의 삼출을 동반한 소양성 인설성 홍반을 주소로 내원 하였다. 병변부에서 시행한 KOH도말 검사상 균사가 반복적으로 관찰되었고 인설과 생검조직을 각각 Sabouroud 포도당 한천배지에 배양한 결과 집락은 비교적 빨리 자라며, 중앙부는 분말형을 보이고 가장자리는 젖빛유리 모양을 나타내었다. 배양한 균집락을 lactophenol cotton blue로 염색후 광학현미경 관찰상 진성 균사와 난형 또는 사방형의 분절포자가 관찰되었으나 분절포자에서 발아하는 분아포자(blastospore)는 관찰되지 않았다. 균주는 37℃ 배양에서 실온보다 느리게 집락을 형성하였으며, Vitek YBC검사상 urease음성, 탄수화물 동화검사는 glucose와 galactose에 양성을 보였다. 조직생검에서 각질층에 균사와 포자가 관찰되었고 진피층의 혈관주위에 호중구 침윤과 핵진이 관찰되었으며, 혈관벽내의 섬유소양 괴사가 관찰되었다. 이상의 임상과 조직소견, 균의 형태학적, 생화학적 검사로 Geotrichum candidum에 의한 표재성 진균증으로 동정하였다. 치료로 itraconazole 일일 200mg 경구 투여와 isoconazole nitrate 1% cream 국소 도포를 병합하여 치료 하였다. 병변은 치료에 느리게 반응하여, 2주후 균은 음전되었으며 4주후 약간의 색소 침착을 남기고 소실되었으며 현재 재발 없이 추적 관찰 중이다. [Kor] Med Myco1 4(1): 69-74]