• 환경위생공학
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• 제14권4호
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• pp.99-109
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• 1999

Enteropathogenic Yersina enterocolitica is an important cause of human and animal disease. Phenotypic and genotypic characteristics currently used to identify Yersinia enterocolitica are not necessarily sufficient to differentiate pathogenic from non-pathogenic strains or to analyze the epidemiology of yersiniae at a molecular level. To improve the characterization of Yersinia enterocolitica, A total of 65 isolates of Yersinia enterocolitica were examined with bioserotyping, antibiotic susceptibilities, PFGE, PCR-ribotyping. Genomic DNA pattern generated by PFGE are highly specific for different strains of an organism and have significant value in epidemiologic investigations. The PFGE analysis of Not I-digested chromosomal DNA of Y. enterocolitica were performed with a CHEF Mapper(Bio-Rad, USA). Not I generated 19 restriction endonuclease digestion profiles(REDP). PCR-ribotyping, performed with primers complementry to conserved regions of 16S and 23S rRNA gene, generated 13 ribotypes. PCR-ribotyping can be considered a good technich for subtyping strains of Y.enterocolitica.

• 대한수학회지
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• 제57권4호
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• pp.1005-1018
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• 2020

A characterization of the C-projective vector fields on a Randers space is presented in terms of 𝚵-curvature. It is proved that the 𝚵-curvature is invariant for C-projective vector fields. The dimension of the algebra of the C-projective vector fields on an n-dimensional Randers space is at most n(n + 2). The generalized Funk metrics on the n-dimensional Euclidean unit ball 𝔹ⁿ(1) are shown to be explicit examples of the Randers metrics with a C-projective algebra of maximum dimension n(n+2). Then, it is also proved that an n-dimensional Randers space has a C-projective algebra of maximum dimension n(n + 2) if and only if it is locally Minkowskian or (up to re-scaling) locally isometric to the generalized Funk metric. A new projective invariant is also introduced.

• 한국수산과학회지
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• 제19권3호
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• pp.177-182
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• 1986

The dynamic mechanical properties of milk gel were examined as function of temperature, concentrations of milk and enzyme. The real and imaginary parts of the complex rigdity G' and G' were measured at $2\%$ strain and 5 rad/s of frequency. The results showed that the rigidity of milk gel was dependent on the concentration of milk (C) in such a way that $\sqrt{G'}{\propto}C$. It was found that gel point ($t_g$) was dependent on the concentration of milk as $t_g{\propto}C$, and on the concentration of enzyme as $t_g{\propto}\;1/(E)$, The activation energy of enzymatic reaction stage and coagulation stage were $21.1{\pm}5.8\;kcal/mol$ and $26.4{\pm}1.14\;kcal/mol$, respectively.

• Journal of Chest Surgery
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• 제12권3호
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• pp.269-273
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• 1979

Obstruction of the right ventricular outflow tract occurs in many various positions. Recently, obstruction due to anomalous muscle bundle has been clearly recognized. This anomaly is caused by a large anomalous muscle bundle, which creates an obstruction low in the body of the right ventricle and divides it into two chambers. Three cases of double chambered right ventricle were treated surgically utilizing cardiopulmonary bypass in the Department of Chest Surgery, College of Medicine, Seoul National University. 1] All of the 3 cases were female. 2] In 2 cases, FKG findings were RVH and RAD, but in case 2, normal EKG findings. 3] In case 2, no pressure gradient between the inflow portion and outflow portion of the right ventricle was observed, but in case 1 and 3, pressure gradients were 70 and 64 mmHg, respectively. 4] In 2 of the 3 cases, type II VSD was combined to double chambered right ventricle. 5] All of the 3 cases were discharged with symptomatic improvement after operation.

• 한국음향학회지
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• 제17권4호
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• pp.30-37
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• 1998

본 논문은 중공형 층상 복합체 멘드릴(mandrel)을 이용하여 기본 공진주파수가 15kHz이상이고, 우수한 감도 특성을 지닌 광섬유 하이드로폰의 최적 구조를 설계하는 것에 관한 것이다. 유한요소법을 이용하여 Al/foraming 및 Nylon/foaming층상 복합체의 공지주 파수를 분석하여 설계 변수의 범위를 결정하였고, 멘드릴 형상에 따른 광음향 감도 특성을 분석하여 최적구조를 결정하였다. 그 결과로 멘드릴의 외경이 감소할수록, 길이가 증가할수 록 감도가 향상되었다. AL 멘드릴의 경우, 내경/외경 비가 낮을수록, Nylon멘드릴의 경우 내경/외경 비가 높을수록 감도 증가를 위하여 효율적이다. 그리고 결정된 최적구조의 Al/foaming 및 Nylon/foaming멘드릴을 사용한 광섬유 하이드로폰의 감도는 각각 1rad./Pa 대비 약 82dB 및 85.7dB 정도 이었고, Al층상 복합체 보다는 Nylon층상 복합체를 이용하는 것이 고 감도의 광섬유 하이드로폰을 제조하는데 유리함을 알 수 있었다.

• Environmental Analysis Health and Toxicology
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• 제18권4호
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• pp.287-294
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• 2003

출아형 효모 Saccharomyces cerevisiae RAD3 유전자는 절제회복 및 세포의 생존에 필수적이며, DNA dependent ATPase와 DNA-RNA helicase활성을 가지고 있는 것으로 알려져 있다. 본 연구는 분열형 효모 Schizosaccharomyces pombe에서 절제회복과 세포의 생존에 필수적인 출아형 효모 RADS유전자와 유사한 유전자를 S. pombe genomic DNA library에서 분리하여 그 특성을 연구하였다. 분리한 RADS 유사유전자를 HRD3 유전자라 명명하였다. 발현 vector pET3a를 이용하여 분리한 HRD3 유전자를 과 발현하였을 때 HRD3단백질은 숙주단백질의 합성 억제 또는 분해 촉진을 유발하여 숙주세포인 대장균에 독성 효과를 나타냄이 관찰되었다. HRD3유전자와 lacZ유전자를 융합시킨 여러 가지 재조합 vector를 만들어 이들 융합단백질을 분리하였다. 이 결과 HRD3단백질의 카르복실 말단 부위가 DNA회복기능과 대장균에서의 독성효과를 나타내는 중요한 부위로 생각된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.284-286
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• 1999

The 7-dial inductive voltage divider (IVD) which is divided the in put voltage precisely upto 10-7 were fabricated by using the toroidal cores made of super-mumetal strips of 0.025 mm thick and special decade switches. The cores ate of the initial permeability of 200,000 and magnetic flux density of 0.5 T. The in phase and quadrature ratio errors are evaluated to less than ${\pm}4{\times}10^{-7}$ and ${\pm}5{\times}10^{-6}$ rad. respectively. The fabrication techniques used are more discussed in this paper.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.401-402
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• 2017

넓은 범위의 토크-속도 특성을 가지는 직류기는 소형에서부터 대형까지 다양한 산업분야에서 폭넓게 사용되고 있다. 이러한 직류기 중 영구자석으로 자기장을 형성하는 영구자석 직류기 (Permanent magnet dc motor, PMDC motor)의 제어방식에 대해 비교 분석했다. 가장 대중적으로 사용되고 있는 진폭 변조 방식 (PWM, Pulse Width Modulation)과 벅-부스트 컨버터 (Buck-Boost converter)를 이용한 직류기 제어 방식에 대해 비교했다. PWM 방식은 인버터를 이용하여 펄스폭을 변조하였고, 벅-부스트 컨버터를 이용하는 방식은 스위치의 듀티비를 제어하여 직류 전압의 크기를 조절하였다. 시뮬레이션 결과 벅-부스트 컨버터를 이용한 방식이 PWM 방식보다 5 rad/s 까지 정착 시간은 54.4 % 단축되었지만, 전력 소모는 194 % 증가하는 결과를 얻었다.

• International Journal of Automotive Technology
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• 제8권5호
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• pp.593-598
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• 2007

A new continuously variable transmission for bicycles(B-CVT) is developed by using a traction drive mechanism having inner and outer spherical rotors. The B-CVT has high power efficiency, large torque capacity, improved drivability and good packageability. The ratio change mechanism for the B-CVT is very simple, in contrast with other traction drive CVTs. After completing a conceptual design, a performance analysis and a detail design, a prototype of the B-CVT has been manufactured. The prototype has rated power of 100 watts, pedal speed of 6 rad/s and an overall speed ratio of 1.0-4.0. A bench test and an actual bicycle test have been performed to verify the practicability of the B-CVT.

• International Journal of Automotive Technology
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• 제6권5호
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• pp.467-473
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• 2005

A continuously variable transmission (CVT) with an inner spherical traction drive was conceptually designed for bicycle usage. The range of the overall speed ratio is from 1.0 to 4.5. The rated power and pedal speed are 100 Watts and 6 rad/s, respectively. The peculiar packageability, high-level power efficiency and high torque capacity were considered in the design process. A compact CVT that can be installed within a $244\times125\times160mm^3$ space and is above 0.9 in efficiency for the rated values was numerically designed. The distribution of efficiency according to the input torque and input speed were calculated. Gradeability in the prescribed operation mode was simulated.