Effects of Pilger Rolling and Heat Treatment on Microstructure and Corrosion Resistance of Ag-electroplated 304 Stainless Steel Tubes

Hyun Park,Woo‑Jin Lee,Jae‑Han Son,Han‑Kyun Shin,Sung‑Kyu Hong,Hyo‑Jong Lee 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

We introduce a cost-effective method that combines electroplating with metal cold working processes to manufacture compositetubes with robust corrosion resistance. First, a 3-step electroplating process was developed to form an adhesive anduniform Ag coating on the outer wall of a 304 stainless steel tube. The process consisted of a Ni-strike step for removing thepassivation layer of the initial 304 tube, Cu deposition for smoothing the surface by adding a buffer layer, and Ag deposition. To reinforce the interfacial adhesion between the electroplated layers and the 304 tube and increase the area of the Ag coating,a pilger rolling or pilger rolling + heat-treatment process was performed after the Ag electroplating process. Scanningelectron microscopy of the composite tubes after each process indicated that the as-deposited Ag coating changed fromhaving a rough to smooth surface after only pilger rolling and with additional heat treatment. Electron backscatter diffractionanalysis of the microstructures and textures of the tubes revealed that dynamic recrystallization occurred extensively duringpilger rolling, resulting in the formation of a relatively defect-free grain structure without heat treatment. Furthermore,electrochemical polarization curves determined that the Ag-coated composite tubes are superior to the uncoated 304 tubein terms of corrosion resistance under Cl−atmosphere, owing to the formation of a AgCl passivation layer during testing. Surface analysis of the composite tubes suggests that the properties of the AgCl passivation layer are related to the grainsize of the Ag coating and the density of plastic-deformation-induced defects.

발열을 동반한 호중구감소증에서 Cefepime 단독투여와 Ceftazidime 및 Tobramycin 병합투여의 효능비교

정현욱,채제욱,강미라,양정채,문치숙,기현균,장현하,오원섭,김기현,백경란,이남용,송재훈 대한감염학회 2004 감염과 화학요법 Vol.36 No.6

목적 : 국내에서 발열을 동반한 호중구감소증이 있는 악성 종양환자에게 경험적 항생제로 베타락탐계 항생제와 아미노배당체의 병합요법의 사용이 일반적이다. Cefepime은 광범위 항균 작용을 가지고 있어, 그람 음성균 뿐만 아니라 그람 양성균에 대해서도 우수한 효과를 나타낸다. 재료 및 방법: 발열을 동반한 호중구감소증이 있는 악성 종양환자를 대상으로 무작위, 공개, 비교 연구를 시행하였다. 대상 환자를 무작위로 cefepime 단독요법군과 ceftazidime 및 tobramycin 병합요법군으로 나누어 투여하고 각각의 임상적 효능과 안전성을 비교하였다. 구강및 인후 점막염이 있는 환자에서 분리된 녹색 연쇄알 구균에 대한 항생제 내성 정도를 조사하였다. 결과 : 대상환자 89명 중 CA 투여군이 48예(53.9%), CT 투여군이 41예(46.1%)이었다. 발열의 유형별로 MDI는 18예(20.2%), CDI는 9예(10.1%), UF는 62예(69.7%)로 두 군 간에 차이가 없었다. CA 투여군과 CT 투여군의 임상적 호전률은 시험약 투여 후 2-4일째 각각 91.7%, 85.4% (P=0.31), 치료 종료 시 각각 91.7%, 100% (P=0.15)로 두 군간에 유의한 차이가 없었다. 치료 종료 시 CA 투여군과 CT 투여군의 세균학적 소실률은 모두 100%로 두 군간의 유의한 차이가 없었다(P=0.78). 점막염이 있는 환자로부터 녹색 연쇄알 구균이 분리된 경우는 25예(28.1%)이었으며, 분리된 녹색 연쇄알 구균은 penicillin, ceftriaxone, cefepime, vancomycin에 모두 감수성을 보였다. 약제 관련 이상 반응의 발생 빈도도 두 군간에 유의한 차이가 없었다. 결론 : 발열을 동반한 호중구감소증이 있는 악성 종양환자의 경험적 항생제로서 cefepime 단독요법은 ceftazidime 및 아미노배당체의 병합요법만큼 효과적이고 안전하였다. Background : Broad-spectrum antibiotic therapy has been recommended as an empirical regimen in cancer patients with febrile neutropenia. Cefepime is a fourth generation cephalosporin with good activity against both gram-positive cocci and gram-negative bacilli. Materials and Methods : To compare the efficacy and safety of cefepime alone with ceftazidime plus tobramycin as empirical regimen for adult cancer patients with febrile neutropenia, a randomized, open label, comparative trial was performed. If the patient showed clinical improvent 72 hours, antibiotic could be changed to oral ciprofloxacin. Clinical and microbiological responses were determined at 72 hours and at the end of therapy. To investigate the antimicrobial resistance of viridans streptococci, swab cultures were obtained from throat in all enrolled patients and antimicrobial susceptibility tests were performed by using microdilution method according to the NCCLS. Results : A total of 89 patients were enrolled. Forty-eight patients received cefepime alone (CA), and 41 patients received ceftazidime plus tobramycin (CT). Demographic and baseline clinical characteristics were similar in both groups (P>0.05). The initial clinical success rate at day 2-4 in group CA (91.7%) was similar with that in CT group (85.4%) (P=0.31). At the end of therapy, the final clinical success rate in CA group (91.7%) was similar to that in CT group (100%) (P=0.15). In 18 patients, with microbiologically defined infections, the eradication rate was 100% in both groups. Adverse events including liver dysfunction (21.3%) and renal dysfunction (2.2%), were similar in both groups (P=0.87). Viridans streptococci were isolated from the throat cultures in 25 cases, and all of these strains were susceptible to penicillin (MIC_(90) 0.12 ㎍/mL), cefepime (1 ㎍/mL), and vancomycin (0.12 ㎍/mL). Conclusion : Efficacy and safety of cefepime monotherapy was comparable to the combination of ceftazidime and tobramycin. It could be used as an alternative empirical regimen for treating cancer patients with febrile neutropenia.

行政私法理論에 관한 考察

韓堅愚,金鉉峻 慶北大學校 1991 論文集 Vol.51 No.-

위선암에서 p53, c-erbB-2, 그리고 DNA ploidy의 상관관계에 관한 연구

강상균,양승하,김대중,김의한,곽현수 순천향의학연구소 1997 Journal of Soonchunhyang Medical Science Vol.3 No.2

Gastric carcinoma is the most common malignant tumor in korea and many oncogenes have found in gastric carcinoma. The relation between the expression of p53 and c-erbB-2 and the prognosis of patient in gastric adenocarcinoma have studied recently, but it is controversy. To evaluate correlation between the pathologic findings including prognostic factors and the expression of p53 and c-erbB-2, and DNA ploidy, we have performed immunohistochemical staining using 83 cases adenocarcinoma and flow cytometry with 56 cases. The results were as follows; 1) The expression rate of p53 was 45.8% in gastric adenocarcinoma. Differentiated, intestinal, advanced, and lymph node metastatic cases showed higher expression rates than poorly differentiated, diffuse, and non-metastatic cases, without statistically significance. 2) The expression rate of c-erbB-2 was 62.6% in gastric adenocainoma. c-erbB-2 was related to differentiated and intestinal types. Advanced and metastatic cases showed higher expression rates of c-erbB-2 than early and non-metastatic cases, but there was not statistic significance 3) Gastric adenocarcinoma showed correlation of DNA diploidy with poorly differentiated type and aneuploidy with differentiated. 4) DNA diploidy and aneuploidy showed correlation with c-erbB-2 negative and postive cases respectively, but correlation between DNA ploidy with p53 expression was not proved. Above results showed that p53 and c-erbB-2 may be related poor prognosis but there was no statistic significance. DNA aneuploidy and diploidy showed correlation with c-erbB-2 expressed and non-expressed cases, respectively, but not with p53 expression.

인터넷 기업가치평가에 관한 연구

이균봉,손명현 釜山大學校 商科大學 2002 釜山商大論集 Vol.73 No.-

This study is to valuate the internet corporate listed on KOSDAQ. The traditional valuation method based on only historical accounting incomes is not fully adequate for evaluation of internet corporate. Though the initial growth rates of internet companies are very high in their early stages, their operating incomes are very low because of high marketing and investment expenditures. This study was conducted on the samples of 42 firms that have reported their ratios of sales changes in individual company level for 3 years listed on KOSDAQ in 2000. Black-Scholes' option pricing model and DCF model were used to test the difference between the estimated corporate value in this study and real stock price. The result of study is as follows : There is no difference between estimated stock price by option model and real stock price. The result shows the stock price estimated by DCF model didn't explain real stock price. The sensitivity analysis by variables in both model indicates that DCF model is more sensitive than option model. DCF model consist of 4 estimated variables, while option model has only one. It can be interpreted that DCF model produces bigger variable measurement errors compared to option model. But option model is more appropriate to value the internet company's stock price than DCF model.

Fe/Si(100) 2×1의 초기 계면에 대한 연구

이상균,장현덕,오진호,박종윤 성균관대학교 기초과학연구소 1995 論文集 Vol.46 No.1

Si(100) 2×1 표면 위에 SPE 법으로 성장된 철 실리사이드의 형성에 대해 연구하였다. 성장된 박막은 중착량과 열처리 온도에 따라 XPS와 RHEED를 사용하여 특징 지워졌다. 상온으로 유지되는 기판 위에 증착 직후의 Fe 층은 Stranski-Krastanov의 성장모드에 따라 성장하였다. low coverage(6분)로 증착한 후, 400℃로 열처리한 시료에서 spotty 2×2 RHEED 패턴이 관측되었다. 이는 매우 낮은 coverage에서도 실리사이드가 형성됨을 확인시켜 주는 결과이다. 또, medium coverage(45분)로 증착된 후, 400℃에서 열처리한 시료에서는 매우 streaky한 패턴이 관측되었다. 이 streaky 패턴은 적층 박막의 매끄러운 표면을 의미한다. 선호되는 박막의 적층 성향은 방위각 편향 β-FeSi_2[010]//Si<110>를 갖는 β-FeSi_2(100)/Si(100)이며, A-type으로 정의되어진다. high coverage에서는 여러 실리사이드가 형성되었으나 RHEED 패턴은 diffuse spot과 높은 background만이 관측되었다. 이는 형성된 실리사이드가 기판과 적층 성장을 하지 않음을 나타낸다. 청정한 Si(100) 2×1으로의 회복은 1100℃ 이상의 온도에서 실현되었다. The formation of the iron silicide grown on Si(100) 2×1 by SPE have been studied accordingly to the changes of Fe deposition amount and annealing temperature using XPS and RHEED. The as-deposited Fe layer was grown with a Stranski-Krastanov growth mode. At the low coverage, the spotty 2×2 RHEED pattern was observed at 400℃. Thus we confirm the formation of the β-FeSi_2 even at the low coverage. At the medium coverage, the RHEED pattern at 400℃ was very streaky 2×2. This well-developed streaky are characteristic of a smooth surface of an epitaxial film. The preferred epitaxial relationship was found to be β-FeSi_2(100)/Si(100) with β-FeSi_2[010]//Si<110>, which is referred to the A-type orientation. At the high coverage, several silicides were observed, but the RHEED pattern of diffuse spot and high background were observed, which means that the silicides did not form the epitaxy with the substrate. Clean Si(100) 2×1 was recovered after annealing at 1100℃.

40ㆍ50대 일부 남성근로자의 골감소증 및 골다공증 유병실태와 위험요인

장윤균,서현주,진영우,정미선,성숙희,박두용,김종순,김수근 大韓産業醫學會 2006 대한직업환경의학회지 Vol.18 No.2

목적: 최근 국내에서도 골다공증과 관련된 생활양식의 규명에 관한 연구가 이루어지고 있으나, 아직까지 남성 골다공증에 대한 연구가 활발하게 이루어지지 않아 40, 50대 남성근로자를 대상으로 유병률을 파악하고, 골감소증 및 골다공증 관련 위험요인을 확인하고자 하였다. 방법: 원자력발전소에 근무하는 40, 50대 남성 근로자 2,073명을 대상으로 2004년 3월~7월 기간동안 생활습관을 파악하기 위하여 자기기입식 전산입력 방식으로 최종학력, 흡연여부, 음주여부, 신체활동 횟수를 조사하였고, 골밀도검사, 체성분검사(체지방률, 허리-엉덩이둘레비), 신체계측(신장, 체중)을 시행하였고, 골밀도 검사는 Osteosys사의 EXE-3000을 이용하여 종골부위를 측정하였고, 체지방률, 허리-엉덩이 둘레비는 Biospace사의 Inbody 3.0을 이용하여 측정하였다. 통계분석은 골감소증 및 골다공증의 관련요인을 분석하기 위해 다중로지스틱회귀분석을 시행하였다. 결과: 연구대상자의 골감소증 및 골다공증 유병률은 22.8%와 3.0%이었으며, 골감소증 및 골다공증의 관련요인으로는 연령이 증가할수록, 흡연자이거나 과거흡연자일 경우, 체질량지수가 25 kg/m^(2) 미만일 경우, 30분 이상 신체활동 횟수가 주 3회 미만일 경우가 유의한 연관성이 있었다. 결론: 성인 남성 40, 50대의 골감소증 및 골다공증의 유병률이 높은 편이었으며, 골감소증 및 골다공증으로 이환을 예방하기 위하여 금연, 활발한 신체활동을 촉진하여 골밀도를 개선시키는 생활습관으로의 변화를 권고해야 할 것이다. Objective: This study was conducted to investigate the prevalence and risk factors of osteopenia and osteoporosis in 40-59 year-old male workers working at nuclear power plants. Methods: Bone density, body composition, and anthropometry data were analyzed for 2,073 subjects were carried out from March 2004 to July, 2004. Educational level, smoking status, drinking status and frequency of physical activity were investigated by self-reported questionnaires through internet to identify lifestyles related to bone mass density. Bone mass density was measured by EXE-3000 of Osteosys Co. And body fat percentage, and waist-to-hip ratio by inbody 3.0 of Biospace Co. Results: The prevalence of ostepeniaosteopenia and osteoporosis was 22.8% and 3.0%, respectively. According to multinominal multinomial logistic regression analysis, age, smoking status (current smoker and former smoker), low body mass index (< 25kg/m^(2)), and frequency of physical activity were significantly associated with osteopenia and osteoporosis. Conclusions: The prevalence of ostcopenia and osteoporosis wasseemed high for the, when it was inferred from subjects' age compared to the results of previous studies. The This study results suggeststhat it is necessary for 40-59 year-old male workers to stop smoking, and exercise regularly in order to prevent osteopenia and osteoporosis.

거울형 자계 구조를 갖는 진공 여과 아크 증착법을 이용한 증착 변수에 따른 다이아몬드상 탄소 박막의 증착 및 물성 분석

박창균,엄현석,서수형,박진석 漢陽大學校 工學技術硏究所 2000 工學技術論文集 Vol.9 No.1

본 논문에서는 거울형 자계 구조를 갖는 진공 여과 아크법을 이용하여 다이아몬드상 카본 박막을 증착하였다. 음극 근처에 영구자석과 자기요크를 사용하여 음극 표면에서의 아크 스팟의 이동도와 아크 플라즈마의 안정도를 증진시킬 수 있었다. 증착압력과 기판전압을 변화시켜 증착 하였으며 이에 따른 물성의 변화를 분석하였다. 그 결과 증착압력 3×10-4 Torr와 기판전압 -50V에서 가장 높은 sp3/sp2 분율을 얻을 수 있었다. 또한 500℃까지 열처리에 따른 박막의 열적 안정성을 평가하였다. DLC films are deposited by using an FCVA deposition system with a mirror-type magnetic field configuration. Permanent magnets and magnetic yokes around the cathode have been observed to enhance the mobility of arc spots on the cathode and the stability of arc plasma. Effects of reactor pressures and substrate biases on structural properties of DLC films deposited are investigated. The results show that the highest sp3/sp2 fraction is obtained when the films are deposited at a pressure of 3 × 10-4 Torr and a bias voltage of -50 V. The variation of the structural properties due to thermal stress up to 500 ℃ is also examined.

위선암에서 p53과 EGFR 및 PCNA 발현에 관한 연구

강현욱,양승하,강상균 순천향의학연구소 1997 Journal of Soonchunhyang Medical Science Vol.3 No.1

Expression of oncogene in the gastric adenocarcinoma was considered as a determinant factor of cancer progression or prognosis by some authors, however, the results were so fluctuated according to the authors that there was no uniform agreement in their clinicopathological correlation as well as in its practical application. To evaluate correlation between the pathologic finding and the expression of p53, EGFR and PCNA, immunohistochemical studies were performed on paraffin-embedded sections of 84 gastric adenocarcinomas. Pathologic findings were classified as 4 subgroups by their histologic types, differentiation, invasion and lymph node metastasis. The correlation of PCNA labelling index with various clinicopathologic factors and oncogene expression was studied. The results were as follows; 1. p53 expression was seen in 47cases(55.56%) of gastric carcinoma, and correlation between p53 expression with tumor type, differentiation, invasion and lymph node metastasis was not proved. EGFR positive expression was found in 37(44.05%) cases and was increased in advanced gastric carcinoma, and cases of lymph node metastasis. 2. Co-expression of p53 and EGFR was observed in 18 cases(33.33%), suggesting existence of both oncogene in the same case, while both negative cases were 18 cases(33.33%) that suggest the possibility of presence of the other factors. 3. PCNA labelling index was higher in advanced gastric carcinoma and in cases of lymph node metastasis, but there was no statistical significance. 4. There was no statistical significance between PCNALI and p53 expression. 5. PCNALI and EGFR expression was parallel with pathologic finding such as differentiation, progression and metastasis of the carcinoma, these results suggest that there was significant correlation between PCNALI and EGFR. 6. PCNALI was statistically significant between two groups of both p53 and EGFR positive and both negative. 7. PCNALI showed statistical significance between EGFR positive and negative groups in cases of lymph node metastasis. In summary, the value of p53 expression as a prognostic factor was still doubtful but EGFR and PCNA expression tended to be associated with tumor progression and seemed to be objective and reliable prognostic factors, respectively. Combined method of EGFR and PCNA thought to be more helpful in preoperative decision or prediction of prognosis in gastric carcinoma.

蠶糞의 成分에 關한 硏究

주현규,박면용,김문주,민경찬 건국대학교 1974 學術誌 Vol.17 No.1