PZT세라믹스에 있어서 길이진동모드의 온도안정성

이개명,현덕수 濟州大學校 産業技術硏究所 2001 산업기술연구소논문집 Vol.12 No.1

Temperature stabilities of dielectric constants and resonant frequencies of the substrates are very important in piezoelectric ceramics oscillators and filters. In this study. it was investigated temperature stability of the length-extensional vibration mode of Pb(Zr_(y)Ti_(1-y)O_(3)+x[wt%]Cr_(2)O_(3) ceramics. The mode can be utilized in fabricating ultra-small 455kHz IF devices. Addition of Cr_(2)O_(3) in morphotrophic phase PZT decreased the variations of dielectric constant. electro-mechanical coupling factor k_(31) and resonant frequency by thermal shock. As additive weight of Cr_(2)O_(3) increased. the temperature coefficient of resonant frequency changed from positive number to negative one. And the composition with zero temperature coefficient of resonant frequency was shifted to the one with increased Cr_(2)O_(3) additive weight by thermal aging.

에이즈 환자에서 발생한 조류형결핵균 뇌수막염 1예

이기덕,박완범,정혜승,강철인,김동민,김홍빈,오명돈,최강원 대한감염학회 2003 감염과 화학요법 Vol.35 No.5

에이즈 환자의 중추신경계 합병증으로 에이즈 바이러스 자체에 의한 합병증, 기회감염, 종양 등이 있다. 저자들은 전신긴장간대발작을 일으킨 31세 남자 에이즈 환자에 발생한 조류형결핵균 뇌수막염을 조직학적 및 미생물학적으로 증명하고, 항비결핵미코박테리아 약제를 고농도로 투여하여 치료하였다. 조류형결핵균 뇌수막염은 결핵성 뇌수막염으로 잘못 진단되면 치명적인 결과를 초래할 수 있으므로, 조직검사를 포함한 적극적인 검사가 필요하다. We report a case of Mycobacterium avium-intraceliuiarae meningoencephalitis found in a 31-year-old patient with AIDS and preexisting disseminated Mycobacterium avium-intracellularae infection. He had been taking highly active antiretroviral therapy and antimycobacterial medications when he developed generalized tonic-clonic seizure. Repeated workups including blood and cerebrospinal fluid examinations and magnetic resonance image (MRI) of the brain revealed nondiagnostic. The diagnosis was made by stereotactic brain biopsy of the nodule, which was detected 9 month after the first seizure attack in brain MRI. Acid-fast bacilli were observed on microscopic exam. Mycobacterium avium-intracellularae was isolated from the biopsy specimen.

PZT세라믹스에 있어서 길이진동모드의 온도안정성

이개명,현덕수 제주대학교 산업기술연구소 2001 尖端技術硏究所論文集 Vol.12 No.1

Temperature stabilities of dielectric constants and resonant frequencies of the substrates are very important in piezoelectric ceramics oscillators and filters. In this study, it was investigated temperature stability of the length-extensional vibration mode of Pb(ZryTi1-y)O3 + x[wt%]Cr2O3 ceramics. The mode can be utilized in fabricating ultra-small 455kHz IF devices. Addition of Cr2O3 in morphotrophic phase PZT decreased the variations of dielectric constant, electro-mechanical coupling factor k31 and resonant frequency by thermal shock. As additive weight of Cr2O3 increased. the temperature coefficient of resonant frequency changed from prositive number to negative one. And the composition with zero temperature coefficient of resonant frequency was shifted to the one with increased Cr2O3 additive weight by thermal aging.

애기마름(Trapa pseudoincisa S. et. Z.)으로부터 sterol 화합물의 분리 및 구조동정

양혜정,송명종,노영덕,김대근,백남인 경희대학교식량자원개발연구소 2007 硏究論文集 Vol.26 No.1

애기마름을 80% MeOH로 추출하고, 얻어진 추출물을 EtOAc, n-BuOH 및 H_(2)O로 용매 분획 하였다. EtOAc 분획으로부터 silica gel과 octadecyl silica gel(ODS) column chromatography를 반복 실시하여 2종의 화합물을 분리하였다. 각 화합물의 화학 구조는 NMR, MS 및 IR 등의 스펙트럼을 데이터를 해석하여, stigmasterol과 stigmasterol 3-O-β-D-glucopyranosyl로 구조 동정하였다. 이화합물은 애기마름에서는 처음 분리되었다. Trapa pseudoincisa was extracted with 80% aqueous MeOH, and the concentrated extract was partitioned with EtOAc, n-BuOH and H_(2)O. Two compounds were isolated from the EtOAc fraction through repeated silica gel and ODS column chromatographies. From the result of spectral data including NMR, MS, IR and GC/MS the chemical structures of the compounds were determined as stigmasterol (compound Ⅰ), and stigmasterol 3-O-β-D-glucopyranosyl (compound Ⅱ). They were isolated from Trapa pseudoincisa for the first time.

분극세기 및 열에이징이 PZT 세라믹스 길이진동모드에 있어서 온도안정성에 미치는 효과

오형철,현덕수,이개명 濟州大學校 情報通信硏究所 2000 情報通信硏究所論文集 Vol.3 No.-

The length extensional vibration mode of a piezoelectric ceramic resonator has the advantage of reduction in its size. In this paper. PZT piezoelectric ceramic specimens with three compositions (Zr/Ti = 56/44, 53/47, 50/50) in Pb(Zr_xTi_(1-x))O₃system were fabricated. We studied effects of poling strength and thermal aging on the vibration mode of the specimens which were poled at 1.5, 2.5, 3.5[KV/㎜] respectively and thermally aged for an hour at 200℃ respectively. The electro-mechanical coupling factor of the length extensional vibration mode increased as poling strength increased. and it decreased after thermal aging. The temperature coefficient of resonant frequency decreased in the 56/44 specimen as poling strength increased after thermal aging. but it increased in the 50/50 specimen. On the conclusion. the changes of poling strength effected on the piezoelectric efficiency and thermal aging contributed to the stabilization of electric dipole structure of the 56/44 specimen.

Human Papillomavirus에 감염된 에이즈 환자에게 발생한 항문암 2예

이창섭,박완범,이기덕,장희창,강철인,박소연,김지현,김홍빈,오명돈,최강원 대한감염학회 2005 감염과 화학요법 Vol.37 No.1

We report two cases of anal cancer in patient with acquired immunodeficiency syndrome infected by human papillomavirus (HPV). One patient presented with huge anal abscess of long duration which developed after incomplete resection of anal warts 2 years ago and the other patient presented with anal bleeding. They were diagnosed as having anal squamous cell carcinoma. Highly oncogenic HPV 69 and 16 were detected by HPV-DNA chip on the previous specimen of warts and anal cancer tissue, respectively. The possibility of anal cancer should be considered in patients infected with human immunodeficiency virus who present anal problems such as anal abscess, anal bleeding, or condyloma accuminatum in anus. 항문암은 HIV 감염자에게 발생하는 빈도가 비감염자에 비해 더 높다. HIV 감염자에게 항문암의 발생 빈도가더 높은 까닭은 항문 성교와 이로 인해서 발생하는 human papillomavirus (HPV) 감염이 이들 환자에게 더 흔하기 때문이라고 생각한다. 항문의 농양, 첨규 콘딜로마로 내원한 HIV 감염자에게서 항문암을 진단하였으며, 이환자로부터 2년 전에 수술로 떼어낸 첨규 콘딜로마 조직에서 HPV 유전형 69를 발견하였다. 또한, 항문 출혈로병원을 방문한 HIV 감염자에게서 항문암을 진단하였으며, 조직 생검으로 얻은 종양 조직에서 HPV 유전형 16를발견하였다. HIV 감염자에게 항문의 농양, 첨규 콘딜로마, 항문 출혈 등의 임상 증상이 발생하면 HPV와 관련된항문암을 감별해야 하겠다.

표준치료에도 불구하고 3차례나 반복해서 발생한 삼일열 말라리아

이해영,한주용,이기덕,박완범,김성한,강철인,문정주,오명돈,최강원 대한감염학회 2002 감염 Vol.34 No.6

황색포도구균의 균혈증에서 초기 항생제 치료가 예후에 미치는 영향

김성한,박완범,이기덕,강철인,최영주,김홍빈,박상원,김의석,오명돈,김의종,최강원 대한감염학회 2002 감염 Vol.34 No.5

성인의 만성 기침에 대한 감별진단으로서의 백일해

박완범,박상원,이기덕,이창섭,장희창,김홍빈,김의종,오명돈,최강원 대한감염학회 2004 감염과 화학요법 Vol.36 No.6

목적 : 백일해는 소아기에 발생하는 전염병으로 오랫동안 알려져 왔다. 그러나, 미국과 유럽에서는 1990년대에 들면서 성인에서도 백일해가 유행하며, 만성 기침 환자의 20% 정도가 백일해를 앓는 것으로 보고하고 있다. 저자들은 국내에서 성인 만성기침의 원인으로 백일해의가능성을 확인하고자 하였다. 재료 및 방법 : 2002년 9월부터 2003년 5월까지 서울의 일개 대학보건진료소 또는 일개 시립병원 외래를 방문한 환자 중 기저 폐질환 없이 1주 이상 기침을 하는 성인을 대상으로 Bordetetlla pertussis에 대한 배양검사와 중합효소 연쇄반응검사(PCR)를 시행하였다. 결과 : 1주 이상의 기침을 하는 성인 102명 중 배양검사에서 양성인 환자는 없었으나 3명(2.7%)에서 PCR 양성이었으며 이들 모두 3주 이상 기침이 지속되었고 백일해의 특징적인 증상을 호소하였다. 결론 : 국내에도 성인에서 백일해가 발생하고 있음을 확인하였고 따라서 성인 만성기침의 원인으로 백일해를 감별 진단해야 한다. Background : Pertussis was long considered a childhood illness. However, in the last two decades, it has been reported as a cause of prolonged cough in adolescents and adults in other countries. Infection of Bordetella pertussis was prospectively searched among adults with a persistent cough. Materials and Methods : Adult patients, who visited either the outpatient clinic of a municipal hospital or a university health service center due to cough of more than six days' duration without underlying pulmonary disease, from September 2002 to May 2003, were enrolled. The culture and polymerase chain reaction (PCR) were used for confirming of B. pertussis infection. Results : 102 adult patients with persistent cough were evaluated. 3 (2.9%) patients were PCR positive for B. pertussis. There were no patients with positive culture. All patients with positive PCR had one or more classic symptoms of pertussis and their cough persisted for 3-7 weeks. Conclusion : We confirmed the morbidity of pertussis in Korean adults with persistent cough. Pertussis should be considered as a differential diagnosis of chronic cough in adults.

간경변증 환자에서 Escherichia colli 균혈증 합병 시 간기능 장애에 따른 C-reactive protein 생성 능력에의 영향

박완범,강철인,김동민,이기덕,장희창,김흥빈,오명돈,이효석,최강원 대한감염학회 2003 감염과 화학요법 Vol.35 No.5