플라즈마 표면복합처리한 구상흑연주철의 열피로 특성

정봉용,주대헌,박주승,김명호 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.9

This paper reports an investigation of the characteristics of plasma duplex treated ductile cast irons during thermal fatigue tests on a thermal cycling rig. The thermal fatigue cracking behaviors and microstructure of untreated and plasma surface treated ductile cast irons have been investigated. Both ferrite and pearlite matrix ductile cast irons were evaluated. During the tests, 60 mm long cylinders with 20 mm diameter were subjected to 1,000 high frequency induction heating and water cooling cycles, lasting 7 and 5 sec, respectively. The thermal fatigue damage was evaluated by analyzing different crack dimensions and distribution by light microscopy. The results showed that the plasma surface treatment increased thermal fatigue cracking resistance. When thermal fatigue cracking occurs, the cracks always initiate at the surface of the specimen. The major path of crack propagation is generally along the ferrite grain boundaries. The hardened layer had an effect on the thermal fatigue property. In addition, the ductile cast iron with an pearlite matrix has a better resistance to thermal fatigue than that of ferrite matrix.

혈액투석 환자에게서 발생한 재생불량성 빈혈 1예

정지용,윤나라,강대웅,오종찬,장재현,선길홍,박경희,정종훈,김현리 朝鮮大學校 附設 醫學硏究所 2005 The Medical Journal of Chosun University Vol.30 No.1

Aplastic anemia is a disease characterized by pancytopenia in the peripheral blood and hypocellular bone marrow with the fatty infiltration. The causes of the acquired aplastic anemia were usually related to drugs and immune-related diseases. A 34-years old man was admitted due to general weakness. He has been going hemodialysis for 2 years because of end stage renal disease (ESRD) due to chronic glomerulonephritis. At admission, laboratory tests showed hemoglobin 6.2 g/dL, hematocrit 18.0 %, WBC 5,710mm (neutrophil 71.8%, lymphocyte 19.1%, monocyte 5.9%), reticulocyte 1.9%, platelet 93,000/mm, Fe 12.8 ug/dL, TIBC 204 ug/dL, ferritin 941.47 ng /ml, haptoglobin 0.72 g/L, vitamin B12 508.17 pmol/L, folate 24 ng/mL, total protein 6.54 g/dL, albumin 3.76 g/dL, Alk. pohsphatase 79 IU/L, AST 30.0 IU/L, ALT 39.7 IU/L, total bilirubin 0.57 mg/dl, BUN 79.4 mg/dl and creatinine 10.18 mg/dl. Peripheral blood smear showed the normocytic normochromic anemia with anisocytosis. Anemia was diagnosed but it was irresponsive to the recombinant human erythropoietin (EPO) and blood transfusion. In the bone marrow aspiration smear were there the hypoplastic myeloid and erythroid precursors. The bone marrow biopsy section showed the hypoplasia of all components (10-20%) and the fatty infiltration. We have experienced one case of the idiopathic aplastic anemia in a patient going through hemodialysis and we just report it with documentary records. 저자들은 혈액 투석 중인 환자에서 약물, 면역계 이상등의 원인을 발견할 수 없었음에도 재생 불량성 빈혈이 발생한 1예를 경험하여 문헌 고찰과 함께 보고하는 바이다.

이담자 효모의 세포간 성응집의 특성과 표면단백질의 관련성

정영기,이태호,최용락,강원대 동의대학교 기초과학연구소 1996 基礎科學硏究論文集 Vol.6 No.1

When mating type A and a cells of heterobasidiomycetous yeast Rhodosporidium toruloides were mix-cultured, both of the mating type cells have shown strong agglutination. But this agglutination was not detactable when the A and a cell were cultured separately. From reagglutination made just after the result of disassembling the agglutination by sonication, we knew that the agglutination was sexual-agglutination, not simple physical cell agglutination. The sexual agglutination was progressed actively on logarithmic phase and, in addition, progressed faster on mating type a cell treated with rhodotorucine A. These sexual agglutination have been inhibited by several protease such as trypsin, pronase, chymotrpysin and thermolysin and inhibited by 5 mM DTT as well.

뇌졸중 환자의 우울증에 영향을 미치는 요인

김대용,정주호 고신대학교 의과대학 2009 고신대학교 의과대학 학술지 Vol.24 No.2

Background: The diseases are getting increasingly chronic as the fast development of medical and scientific technical advances prolong the human life span. Among many chronic diseases, the apoplexy leads to partial paralysis, speech disorder, perception disorder and paresthesia and motor disturbance. It also causes mental disorder to patients. This research was aimed to check the level of stress perceived by apoplexy patients according to the socioeconomic factors and disease characteristics. Method: Applying the Beck's depression measurement, we surveyed the depression level of 150 inpatients and outpatients who have been currently taken care of by the departments of neurology, neurosurgery and rehabilitation at a university hospital and two general hospitals in Busan. Results: According to this survey, 84 out of 150 patients are estimated to be depressed, accounting 56% of the total samples. The depression level related to the socioeconomic factors is higher in patients who are older, separated from spouse and who have low education level and financial dependence on offsprings. The depression level related to the neurological manifestations is higher in patients who have multiple strokes, long term illness, bilateral paralysis, and other neurological sequelae (particularly gait disturbance). Conclusion: The result suggest that poststroke patients are highly likely to suffer from depression by various socioeconomic factors and neurological manifestations. Therefore, it can be concluded that poststroke patients need not only medical treatments and rehabilitation procedures but also more proactive mental remedies and social supports considering patient's backgrounds and characteristics.

Bi-계 고온초전도 선재의 Jc 향상에 관한 연구(Ⅰ)

정대영,오영우,한일용 慶南大學校 附設 工業技術硏究所 1992 硏究論文集 Vol.10 No.-

Ag가 피복된 Bi-계 고온 초전도 선재의 임계전류밀도(Jc)향상을 위하여 분말 충진법과 아울러 압연과 소결의 혼합공정의 반복법을 사용하였다. 선재에서 높은 Jc를 얻기 위한 요인으로는 높은 고온상(Bi-2223상)분율, 방향화된 미세조직, 입계에선의 강한 결합, 미립의 비 초전도상의 균일한 분포등이다. 압연을 통하여 유된 입자의 방향적 배열화에 의하여 weak-link는 상당히 제거될 수 있었다. 본 연구에서 얻어진 가장 높은 Jc는 77K와 OT에서 6,350 A/cm²의 값이었다. In order to improve the critical current density(Jc)by obtaining well grain-aligned morphology, Ag-sheathed Bi(Pb)-Sr-Ca-Cu-O superconducting tapes were prepared using the powder-in-tube method and a repeatition of the combined process of rolling and sintering. Key factors for obtaining high Jc in the tapes are known to be high content of hegh-Tc phase(Bi-2223 phase), well grain-aligned morphology, good bonding at grain boundaries and uniform dispersion of nonsuperconducting particles. The weak-links could be considerably eliminated by directional grain-alignment induced by rolling. The highest Jc obtained in the present study was 6,350 A/cm²at 77K and OT.

Multiple Spinal Intradural Schwannomas Combined with Sequestered Lumbar Disc Herniation

김대용,김진욱,정주호,조재훈 고신대학교 의과대학 2008 고신대학교 의과대학 학술지 Vol.23 No.2

In this report, we describe a case of multiple intradural schwannomas in the spine combined with a upward sequestered disc herniation at L4-L5. It is often difficult to differentiate this tumor from lumbar disc herniation, especially a sequestered hernia. Gadolinium-enhanced MR images were a useful preoperative examination modality for differentiating these lesions from other diseases. Microscopically, the intradural tumors were successfully removed. The dura maters of the L2 and S1 were opened microsurgically, allowing the nerve fibers involved in the tumor to be identified. The involved fibers were cut around the tumor, and the lesion was resected while the intact nerve fibers were preserved. An upward sequestered lumbar disc herniation at L4-L5 was also successfully removed. Based on histological examination of the resected specimen, the tumors were diagnosed as schwannomas. Microsurgery allowed the tumors to be removed with minimal impairment from cutting of nerve fibers in the each nerve root.

호염세균으로부터 추출한 카로테노이드 색소의 안정성

정영기,최병대 동의대학교 기초과학연구소 2000 基礎科學硏究論文集 Vol.10 No.1

A carotenoid pigment, which was a determinant for food quality, was extracted from a marine halophilic bacteria. The stability of the pigment extract was investigated for a food additive. The optimum temperature for stability was 20℃. The pigment degradation was significantly affected by solvent polarity, however, stable in salvent methanol and ethanol. The pigment degradation was highly sensitive to light and UV exposure.

一柱門의 建築形式에 關한 硏究

정대열,이재환,이용대,예명해 대구대학교 과학기술연구소 2001 科學技術硏究 Vol.8 No.2

The purpose of this study is to discover the architectural type of 「Il-joo-moon」 It deals with 「Il-joo-moon」 that has been built before 1910 in Gyoung-sang province. This study analyzes type of member, jointing method, frame structure method by dividing 「Il-joo-moon」 into four parts such as roof, bracket system, frame structure, podium. The results of this analysis are as follows 1) Roof: The 「Pal-ssac」 style of roof and the 「Matt-bae」 style of roof are dominant and double caves mainly appears. 2) Bracket system: The arrangement of bracket system can be divided into one-line-arrangement and two-line-arrangement. As far as 「Chul-mock-soo」 concerned, 3 or 4 「Chul-mock-soo」 is predominent. 「Tong-jae-gong」 has been used to connect front and back bracket system for some 「Il joo-moon」. When it comes 「jae-gong」, 「Sue-soe」 style, 「Yon-bong」 style and 「Yon-hwa」 style are mainly seen. 3) Frame structure: There are 5 forms in classifying frame structure depending on the jointing method of main-column, diagonal member, sub-column etc. and weight transmission method. 4) Podim: Natural foundation stone is majority. It is judged that 「Il-joo-moon」 has no podium or natural ones, however, it has recently been converted into artificially processed podium in many cases.

이담자균 효모의 성분화 과정중 인지질의 작용과 배지조성의 제한이 성분화에 미치는 영향

정영기,강원대,남수완 동의대학교 기초과학연구소 1997 基礎科學硏究論文集 Vol.7 No.1

The action of phospholipid on the rhodotorucine A(Rh.A) acceptance by heterobasidiomyceteous yeast Rhodospori-dium toruloides mating type a cells and the effect of medium composition during sexual differentiation were investigated. Activation of trigger peptidase(TPase) was very sensitive to the originated phospholipid from R. toruloides and was more sensitive to phospholipid liposome made up of phospholipid. Phospholipid present on the membrane of mating type a cells consists of phospatidylglycerol(PG), phosphatidylethanolamine(PE), phospatidylcholine(PC), phospatidylinositol(PI), and phosphatidylserine(PS) of 12.9, suprisingly 45.4, 11.0, and 13.9%, respectively. As the result of using C-1 and N-1 mediums which limited C and N sources capable of inhibiting the synthesis of phospholipid. it resulted inhibiting sexual differentiation and production of Rh.A from mating type A cells.

말기신부전 환자에서 혈액투석 전후의 QT간격분산 비교

강대웅,정지용,윤나라,안치용,김종오,신병철,정종훈,김현리 朝鮮大學校 附設 醫學硏究所 2006 The Medical Journal of Chosun University Vol.31 No.2

Background: Some cases of QT interval, corrected QT interval (QTc), QT dispersion (QTd) and corrected QT dispersion (QTcd) have been reported in ESRD, but these results are variable and the influence of a hemodialysis is still controversial, In this study, we investigated the effect of hemodialysis on QT and QTc interval and QT and QTc dispersion in patients with ESRD 15 min before and 15 minute after each hemodialysis. Methods: Sixty-seven patients with ESRD (men 33 & women 34) on three-times stable hemodialysis (>3 months) were randomly enrolled. Fifty control subjects with a similar age and normal renal function were enrolled from this hospital. Routine biochemical studies were measured pre- and post dialysis, at the time of the ECG. Plasma Na+, K+, BUN, creatinine, ionized calcium and phosphate were checked. Twelve-lead electrocardiographs were performed at 10㎜/mv and 50㎜/s using a HewIett-Packard Pagewriter 100, before and after a single hemodialysis session.The QT interval was measured from the onset of the QRS complex to the end of the T wave. If the end of the T wave was not clear in a particular lead then it was excluded from analysis. When U waves were present, the end of the T wave was taken as the nadir between the T and U waves. Each QT interval was corrected for heart rate using Bazett's formula (QTc==QT/√(RR)) (ms). The difference between maximal and minimal QT interval duration was defined as QT dispersion (QTd) in each of the 12 leads. Result: This study demonstrates that QT, QTd, QTcd is higher in hemodialysis patients compared with control subjects, and QT and QTd rise postdialysis to levels comparable to those seen acutely following myocardial infarction, when patients are at greatly increased risk of potentially fatal ventricular arrhythmias, Conclusions: QT interval and QT dispersion, markers of risk for arrhythmias and sudden death, are elevated in hemodialysis patients, and rise postdialysis. QT interval and QT dispersion is an easily obtainable, noninvasive, simple, inexpensive, and widely available method of risk stratification in uremic patients receiving chronic dialysis. Additional studies are needed to clarity whether increased postdialysis QT dispersion results in an increased occurrence of arrhythmias.