실란 프라이머 도입에 의한 동박-에폭시 계면접착 향상

정경호,이보현,김성훈,Jeong, Gyeong-Ho,Lee, Bo-Hyeon,Kim, Seong-Hun 한국재료학회 1999 한국재료학회지 Vol.9 No.12

In this study, the silane primers were introduced to improve the interface adhesion between copper and epoxy. Especially, the polymer types obtained by solution and emulsifier-free emulsion polymerization of vinyltriethoxysilane and the low molecular weight types of 3-aminopropyltriethoxysilane(3-APTES) and 3-glycidoxypropyltrimethoxysilane(3-GPTMS) were used to improve the adhesion strength between epoxy and copper. Also, the surface of copper was treated by 1,1,1-trichloroethane. According to the results, the interfacial adhesion strength of copper-epoxy increased about 2~5 times with the introduction of silane primer. Also, the optimum treatment time of copper surface was about 10 minutes. Additionally, the adhesion strength as a function of concentration of low molecular weight silane was maximum at about 0.5 vol.% for 3-APTES and about 0.2 vol% for 3-GPTMS.

3차원 근접정보를 이용한 검사시스템의 성능평가와 디자인 고려사항

정경호,Jeong, Gyeong-Ho 대한인간공학회 2004 대한인간공학회지 Vol.23 No.1

Due to economical or technological reasons. humans are responsible for inspection functions in many cases. Humans. however. are rarely perfect. thus allowing non-confirming parts to be processed. As the attributes of interest or the variety of products increases. the inspection system becomes less effective because of the sensory and cognitive limitations of human inspectors. Any means that can support or aid the human inspectors is necessary to compensate for inspection difficulty. Augmented reality (AR) offers a new approach in designing an inspection system as a means to augment the cognitive capability of inspectors by providing the 3D spatial proximity between two information channels. The experimental results suggest that AR might be an effective tool that reduces inspection time without sacrificing the measuring accuracy.

국소적 뇌피질 이형성증의 곡면재구성영상

정경호,이상용,김종수,김영곤,이영환,정수현,Jeong, Gyeong-Ho,Lee, Sang-Yong,Kim, Jong-Su,Kim, Yeong-Gon,Lee, Yeong-Hwan,Jeong, Su-Hyeon 대한영상의학회 2002 대한영상의학회지 Vol.46 No.6

Purpose: To describe curved planar reconstruction imaging (CPRI) and determine its usefulness in the evaluation of focal cortical dysplasia of the brain. Materials and Methods: In 17 cases of focal cortical dysplasia [cortical dysplasia (n=9), schizencephaly (n=5), and heterotopia (n=3)], CPR images were created using a multiplanar reconstruction program and imaging data obtained during T1 magnetizationprepared rapid acquisition gradient-echo MR imaging. We assessed the precise configuration of abnormalities and their relation to adjacent gyri and sulci. Results: CPRI showed the brain cortex as a 2D panoramic image, demonstrating the precise configurations and locations of dysplasia-associated abnormalities and their relation to adjacent gyri and sulci, and the precise shape of the gray-white matter interface. Conclusion: CPRI can provide important radiological information about the extension and configuration of focal cortical dysplasia, and its relation to neighboring cortical structures. We believe that CPRI should form an essential part of the routine investigation of suspected cases of focal cortical dysplasia.

센서,박막재료 (1) : 전처리 조건에 따른 탄소나노튜브의 성장 특성

정경호 ( Jeong Gyeong Ho ),홍병유 ( Hong Byeong Yu ) 한국전기전자재료학회 2003 한국전기전자재료학회 하계학술대회 논문집 Vol.2003 No.1

졸음운전의 자동 검출 및 각성 시스템 개발에 관한 연구

김남균,정경호,김법중,Kim, Nam-Gyun,Jeong, Gyeong-Ho,Kim, Beop-Jung 대한의용생체공학회 1997 의공학회지 Vol.18 No.3

Driving is a complex vigilance task that includes improper lookout, excessive speed and inattention. The primary objective of this research is to detect driver drowsiness so that the driver can be alerted to an impending traffic accident in performance. We developed the automatic detection and warning system during drowsy driving. A drowsiness detection system must be able to monitor driver status and detect the detrimental changes of a driver performance. Eyeblink has been found to be a reliable factor of drowsiness detection in earlier studies. As an additional parameter, we also considered the yawning which often occurs in a low vigilance state and predicts the drowsy state. We used a computer vision method to extract the eyeblink and yawning in the face image sequences. When the drowsy state was detected, the driver was refreshed by alarming device and menthol scent generator after deciding the warning level by fuzzy logic. For the evaluation of our system, we measured the physiological parameters such as EOG and EEG. The results indicated that it is possible to detect and alert the driver drowsiness temporarily or continuously by using our system.

Mn-DPDP 조영증강 자기공명영상: 국소 간 종양 발견에 적합한 영상 기법에 대한 연구

이정민,정경호,조백환,김종수,Lee, Jeong-Min,Jeong, Gyeong-Ho,Jo, Baek-Hwan,Kim, Jong-Su 대한영상의학회 2002 대한영상의학회지 Vol.46 No.4

Purpose: To assess the diagnostic value of Mn-DPDP for the detection of focal hepatic tumors on MR images and to determine the optimal pulse sequence to maximize its effect. Materials and Methods: Twenty-three patients with 32 focal hepatic tumors were examined by means of 1.5-T MRI. Before and after the intravenous administration of Mn-DPDP, five pulse sequences were used to obtain T1-weighted images: two-dimensional fast low-angle shot (2D FLASH) with/without fat saturation (FS), spinecho (SE), and three-dimensional fast low angle shot reconstruction (3D FLASH) with/without FS. Quantitative assessment involved determination of the signal-to-noise ratio (SNR) of the liver and the tumor, the percentage signal enhancement ratio (PSER) of the liver, and tumor-to-liver contrast to noise ratio (CNR). Pulse sequences were also evaluated subjectively for tumor conspicuity, delineation, and image artifact. In addition, two experienced radiologists compared tumor detection rates between precontrast and postcontrast images. Results: Mn-DPDP had a marked effect on liver SNR and absolute CNR at all pulse sequences (p<0.05). On postcontrast images, PSER and absolute CNR of the liver were highest at 3D FLASH and 2D FLASH FS, respectively, and significantly higher at GRE than at SE (p<0.05). On postcontrast images, the CNR of focal nodular hyperplasia and hepatocellular carcinoma was positive, while that of hemangioma, metastasis and cholangiocarcinoma was negative. The postcontrast CNR of all tumors except hepatocellular carcinoma increased more than 100%. Qualitative studies showed that tumor conspicuity increased significantly at all sequences except SE, and delineation increased significantly except at SE and postcontrast 2D GRE FS. After Mn-DPDP, GRE more effectively demonstrated tumor conspicuity and image artifact than did SE, and GRE other than 2D FLASH FS was also better than SE for tumor dilineation (p<0.05). The sensitivity of all postcontrast images increased and the tumor detection rate at GRE was significantly higher than at SE. Conclusion: Mn-DPDP favorably affects tumor-to-liver contrast, and may be useful in the imaging of focal hepatic tumors, more so with 2D or 3D FLASH pulse sequences than with SE.

Improvement of Polyimide/Epoxy Adhesion Strength from the Modification of Polyimide Surface and Epoxy Adhesive

김성훈,이동우,정경호,Kim, Seong-Hun,Lee, Dong-U,Jeong, Gyeong-Ho Materials Research Society of Korea 1999 한국재료학회지 Vol.9 No.1

In order to minimize flexible printed circuit(FPC), which is used in computer, communication, medical facility, aviation space industry, it is required to improve the interfacial adhesion of polymide/epoxy or polyimide/polyimide consists of FPC. In this study, it was considered to improve the adhesion strength of polyimide/epoxy joint by introducing functional group on polyimide film and improving mechanical property of epoxy. Functional group on polyimide film was introduced by changing polyimide film surface to polyamic acid in KOH aqueous solution. The optimum conditions for surface modification were the concentration of 1M KOH and treatment time of 5min. Also, the optimum adhesion strength of polyimide/epoxy joint was obtained using rubber modified epoxy and polyamic acid as a base resin and curing agent of epoxy adhesive, respectively. The degree of surface modification of polyimide film examined with contact angle measurement of FTIR, thus modification of polyimide to polyamic acid was identified. Fracture surface of plymide/epoxy joint was analyzed by scanning electron microscopy, and modified polyamic acid reimidezed to polymide as increasing curing temperature.

충전 및 미충전 미가교 고무의 탄성반응

이경율 ( Lee Gyeong Yul ),신수 ( Sin Su ),정경호 ( Jeong Gyeong Ho ),윤태호 ( Yun Tae Ho ),강신영 ( Kang Sin Yeong ) 한국고무학회 2003 엘라스토머 및 콤포지트 Vol.38 No.3

Elastic responses on both pure natural rubber melts with different molecular weights and the rubber compounds mixed with various types of carbon blacks were investigated in this study. Furthermore, the degree of bound rubber was measured for various carbon blacks with different sizes and structures in order to study the interaction between the rubber and carbon blacks, and to study the correlation between the interaction and the elastic responses. As a loading amount of carbon black increased, the degree of bound rubber became higher, particularly for carbon-black particles with smaller sizes and higher structures. The elastic responses of the rubber melt filled with carbon black remarkably improved, as compared with those of unfilled rubber melt, specially in carbon black showing higher contents of bound rubber. Stress relaxation was more delayed and recovery behavior became more elastic, as the molecular weight of the rubber melt increased and the size of carbon-black particles was decreased. Permanent set became higher, as the molecular weight of the rubber melts decreased and the size of carbon-black particles increased.

Aneurysm Formation of Cervical Aortic Arch Combined with Subaortic Left Innominate Vein: Case Report

한영민,구자홍,진공용,곽효성,정경호,Han, Yeong-Min,Gu, Ja-Hong,Jin, Gong-Yong,Gwak, Hyo-Seong,Jeong, Gyeong-Ho The Korean Radiological Society 2004 대한영상의학회지 Vol.50 No.1

An asymptomatic 26-year-old man was initially admitted with a suspicious mediastinal mass. On the basis of the contrast-enhanced chest CT findings, aneurysm formation involving the left cervical aortic arch associated with subaortic left innominate vein was diagnosed. The aneurysm was confirmed by MR angiography and DSA. The arch aneurysm was surgically removed. We describe this case, and review the literat

Effectiveness of Low-Dose Erythromycin Therapy in Diffuse Panbronchiolitis: Assessment with Serial Changes on High-Resolution CT and Pulmonary Function Test

Jin, Gong-Yong,Han, Yeong-Min,Lee, Heung-Beom,Gwak, Hyo-Seong,Jeong, Gyeong-Ho,진공용,한영민,이흥범,곽효성,정경호 The Korean Radiological Society 2003 대한영상의학회지 Vol.48 No.6

Purpose: To determine evaluate the clinical effectiveness of low-dose erythromycin (EM) therapy in patients with diffuse panbronchiolitis (DPB), and to correlate the pulmonary function testing (PFT) changes seen at serial high-resolution CT (HRCT) withthe results of post-treatment.