Bi-S 쾌삭강의 칩생성특성

이영문,조삼규,장은실,태원의,심보경 韓國工作機械學會 2000 한국생산제조학회지 Vol.9 No.3

In this study, the characteristics of chip formation of the cold drawn Bi-S free machining steels were assessed. And for comparison, those of the cold drawn Pb-S free machining steel, the hot rolled low carbon steel which has MnS as free machining inclusions and the conventional steels were also investigated. During chip formation, the cold drawn free machining steels show relatively little change in thickness and width of chip compare to those of the conventional carbon steels. And a single parameter which indicates the degree of deformation during chip formation, 'chip cross-section area ratio' is introduced. The chip cross-section area ratio is defined as chip cross-section area is divided by undeformed chip cross-section area. The variational patterns of the chip cross-section area ratio of the materials cut are similar to those of the shear strain values. The shear stress, however, seems to be dependent on the carbon content of the materials. The cold drawn Bi-S and Pb-S steels show nearly the same chip forming behaviors and the energy consumed during chip formation is almost same. A low carbon steel without free machining aids shows poor chip breakability due to its high ductility. By introducing a small amount of free machining inclusions such as MnS, Bi, Pb or merely increasing carbon content the chip breakability improves significantly.

Phenotypic characteristics of<i>Streptococcus iniae</i>and<i>Streptococcus parauberis</i>isolated from olive flounder (<i>Paralichthys olivaceus</i>)

Nho, Seong-Won,Shin, Gee-Wook,Park, Seong-Bin,Jang, Ho-Bin,Cha, In-Seok,Ha, Mi-Ae,Kim, Young-Rim,Park, Yon-Kyoung,Dalvi, Rishikesh S.,Kang, Bong-Jo,Joh, Seong-Joon,Jung, Tae-Sung Oxford University Press 2009 FEMS microbiology letters Vol.293 No.1

<P>The etiological agents of streptococcosis were isolated from diseased olive flounder collected on the Jeju island of Korea. A total of 151 bacterial isolates were collected between 2003 and 2006. The isolates were examined using various phenotypic and proteomic analyses, including sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting, and glycoprotein assays. In addition, isolates were grown on blood agar to assess hemolytic activity, and biochemical assays were performed using the API20 Strep kit. Our results revealed that all isolates were nonmotile, Gram-positive cocci that displayed negative catalase and oxidase activities. Multiplex PCR assays revealed that 43% and 57% of the isolates were Streptococcus iniae and Streptococcus parauberis, respectively. These results were consistent with those of the SDS-PAGE and immunoblot analyses using whole-cell lysates of bacterial isolates. Significant differences were observed with respect to the Voges-Proskauer, pyrrodonyl arylamidase, alkaline phosphatase, and hemolytic activities of the S. iniae and S. parauberis isolates. Isolates of S. iniae displayed uniform profiles in the immunoblot and glycoprotein assays; however, immunoblot assays of S. parauberis isolates (using a chicken IgY antibody raised against a homologous isolate) revealed three distinct antigenic profiles. Our findings suggest that S. parauberis and S. iniae are endemic pathogens responsible for the development of streptococcosis in olive flounder.</P>

독성물질의 세포사 기전 및 세포사 유발물질의 검색법 개발에 관한 연구(Ⅰ) : 독성물질로 인한 파킨슨병 모델에서의 세포사 기전 연구 Study on the cell-death mechanisms of toxin-induced parkinsonism

강태석,김종민,서경원,김영옥,김준규,오재호,이윤동,김규봉,오정자,송연정,임종준,전범석,문전옥,최광식 식품의약품안전청 2000 식품의약품안전청 연보 Vol.4 No.-

MPTP 독성물질이 도파민성 신경세포에 선택적으로 작용하여 산화성 손상에 의한 신경세포사를 일으키는 것을 이용하여 파킨슨병의 동물모델을 만들고, 이를 통해서 아폼토시스를 비롯한 포사의 기전에 대한 연구 및 너코틴의 신경세포 보호효과 여부를 판정하는 실험을 병행하고자 하였다. 파킨슨꾐의 동물모델을 MPTf 독성 물질을 이용하여 확립하였으며, MPTP(30mgag, i.p.)를 투여한 후 1, 2,3, 4, 5일째 흑질 조직을 채춰하여 tarm로 박걸하여 tyrosine hydroxylase 면역조직화학염색을 수행하여 cell countif우한 결과, control은 57.635ce11s, 1일째 친.OfDells,2일째 57.9±6cells,3일릴 없.3±죠ells, 4일째 49.0츠3cells, 5일째 39.4±Scells료 4, 3일째 뚜렷한 신경세포 수의 감소를 보였다. 신경세포사 기전 규명을 위한 아폼토시스 분걱에서는 벼PTP 투여 후 1, 2, 3, 4, 5일째 조직을 채취하여 Hoechst staining, TUNEL staining을 수곡하였는데 양성 반응을 보인 신경세포는 관찰되지 않아. 아폼토시스로 인한 세포사가 관찰되지 않았다. bIPTP 파킨슨병 동물모델에서 nicotine 보호효과 탐색에 관한 실험은 nicat푸e 0.2mgAg을 5일 퐁안 투여 후 리『fP(30mgag)를 CS7Bt/6 마은스에 복강 내주사로 nicotine과 병용 투여한 후 1, 2, 3, 4, 5일째 뇌를 적출하땄다. 신경세포사가 뚜렷이 관찰되기 시작하는 4, 5일째의 신경세포 수의 감소 정도를 20. 30% 정도 약화시키는 경향을 보였으나, nicotine 보호효과에 대한 추가 실헝이 현재 수행 중에 있다. The cause of Parkinson's disease (PD) is largely unknown. However, free radical toxicit? may plaf a role ip. the degeneration of substantia nigra, which is the Hajorfocus of pathological damages in PD. Recently, a neuroprotective effect of nicotine in PD has been suggested. Therefore, the mechanism of neurodegenerafion and protective potential o( nicotine in PD were investigated in the experimental modeB of Pll using a neurotoxin, C57BL/6mice were administered with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg,j.p.). The degree of neurodegenerafion was determined by immunohistochemical stainiHB oftyrosine hydroxylase (TH). TH-positive cells on nigral sections were found 56.0 ±4, 57.9 ±6,52.315ce11s, 49.0±3cells, and 39,4±Scells at days 1, 2, 3, 4, 5, respectively (controls : 57.6±Scells). Hoechst and TUNEL staining showed no evidence of apoptosis. The exandnation on themice co-adrunistered with nicotine(0.2mgAg) and MPTP(30mgag) revealed a tendency ofnicotine protective effects. At days 4 and 5, the degree of TH-positive cells was decreased by20-30%, In corclusiffn, the role of apoptosis was not evidenced in this MPTP modeB of PB.The possible proteccon by nicotine should be elucidated with further studies.

星湖學派의 陽明學 受容

徐鍾泰(S?h Chong-tae) 한국사연구회 1989 한국사연구 Vol.66 No.-

Lymphoepithelial Carcinoma of the Submandibular Gland - A Case Report

Jang, S.-J Korean Academy of Medical Science 1997 Journal of Korean medical science Vol.12 No.3

Hitachi 747 자동분석기의 실험평가

박종성,황성준,이승관,이창규,이국성,강영태 高麗大學校 倂設 保健大學 保健科學硏究所 1994 保健科學論集 Vol.20 No.1

Comparison of methods studies should compare results by new or proposed method with those by a reference quality method or other generally accepted analytical method for which the performance is documented. The least squares method is frequently used to calculate the slope and intercept of the best line through a set of data points. However, least squares regression slopes and intercepts may be incorrect if the underlying assumptions of the least squares model are not met. Latest in the line of Hitachi systems, the Hitachi 747 is a high volume, random access system. It has capabilities for running states, automatic return of samples with a smaller volume, parameters for serum/plasma and urine, and multitasking capability. We performed method comparison studies against the current method for 8 different analytes with 49 samples for each chemistry. Also, Data analysis was performed according to the Kuwa protocol. The results of statistical studies indicate an acceptable performance over a clinically relevant range. We conclude that the Hitachi 747 analyzer is a reliable, precise and accurate system for routine clinical analytes. Its convenience and simplicity make it superior to the current autoanalyzer for our clinical applications in a hospital setting.

The Thought and Literary Achievement of Hong Tae-yong

KIM TAE-JOON,S?l Sun-bong(번역자) The Academy of Korean Studies 1988 Korea Journal Vol.28 No.5

Sulfur‐Infiltrated Micro‐ and Mesoporous Silicon Carbide‐Derived Carbon Cathode for High‐Performance Lithium Sulfur Batteries

Lee, Jung Tae,Zhao, Youyang,Thieme, Sö,ren,Kim, Hyea,Oschatz, Martin,Borchardt, Lars,Magasinski, Alexandre,Cho, Won‐,Il,Kaskel, Stefan,Yushin, Gleb WILEY‐VCH Verlag 2013 ADVANCED MATERIALS Vol.25 No.33

<P><B>Novel nanostructured sulfur (S)–carbide derived carbon (CDC) composites</B> with ordered mesopores and high S content are successfully prepared for lithium sulfur batteries. The tunable pore‐size distribution and high pore volume of CDC allow for an excellent electrochemical performance of the composites at high current densities. A higher electrolyte molarity is found to enhance the capacity utilization dramatically and reduce S dissolution in S‐CDC composite cathodes during cycling.</P>

Abnormal photoluminescence properties of GaN nanorods grown on Si(111) by molecular-beam epitaxy

Park, Young S,Kang, Tae W,Taylor, R A IOP Pub 2008 Nanotechnology Vol.19 No.47

<P>We have studied the photoluminescence properties of GaN nanorods grown on Si(111) substrates by radio-frequency plasma-assisted molecular-beam epitaxy. The hexagonal shaped nanorods with lateral average diameters from 30 to 150 nm are obtained by controlling the Ga flux with a fixed amount of nitrogen. As the diameters decrease, the main emission lines assigned as donor bound excitons are blueshifted, causing a spectral overlap of this emission line with that of the free exciton at 10 K due to the quantum size effect in the GaN nanorods. The temperature-dependent photoluminescence spectra show an abnormal behaviour with an ‘S-like’ shape for higher diameter nanorods. The activation energy of the free exciton for GaN nanorods with different diameters was also evaluated.</P>

Measurement of burr removal rate and analysis of machining parameters in ultrasonic assisted dry EDM (US-EDM) for deburring drilled holes in CFRP composite

Kurniawan, Rendi,Thirumalai Kumaran, S.,Arumuga Prabu, V.,Zhen, Yu,Park, Ki Moon,Kwak, Ye In,Mofizul Islam, Md.,Ko, Tae Jo Elsevier 2017 MEASUREMENT -LONDON- Vol.110 No.-

<P><B>Abstract</B></P> <P>An ultrasonic assisted dry electrical discharge machining (US-EDM) process in a gaseous fluid medium was proposed to remove the burrs formed on the exit region of a drilled hole. In preliminary experiment, three different electrode tools (copper, brass, and aluminum) were utilized. In secondary experiment, US-EDM and dry-EDM were compared and performed using the copper tool. US-EDM parameters, such as capacitance (C), pulse-on time (T<SUB>ON</SUB>), and vibration amplitude (A<SUB>p-p</SUB>) were considered as functions of the predicted burr removal rates (BRRs) model. Based on signal to noise (S/N) ratio analysis, machining parameters C=10<SUP>−2</SUP> µF, T<SUB>ON</SUB> =150µs, and A<SUB>p-p</SUB> =4.919µm provided the optimal BRR. The BRR was affected the most by capacitance, followed by pulse-on time and ultrasonic vibration amplitude. The copper tool provided a higher BRR than other tools. US-EDM is considerably effective when T<SUB>ON</SUB> is low and the performance of US-EDM is better than that of Dry-EDM. Scanning electron microscopy (SEM) analysis showed that the US-EDM method created a heat-affected zone surrounding the machined surface of the deburred exit hole in range of 200µm–500µm.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The novelty of a burr removal rate (BRR) model was proposed and validated in this study. </LI> <LI> The influence of the US-EDM process parameters on the BRR value was studied. </LI> <LI> The relationship between the input and output processes was evaluated statistically. </LI> <LI> The optimal machining parameter for the BRR value was validated. </LI> <LI> The comparison between US-EDM and Dry-EDM process was evaluated. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>