• Proceedings of the KIEE Conference
• /
• 1994.07a
• /
• pp.138-140
• /
• 1994

The torque production of SRM is dependent on the variation of inductance which is related to rotor position angle. So the realization of high efficiency SRM is achieved by design of optimal inductance profile appropriate for magnetic capacity of motor. This can be obtained by optimal design of winding number of stator. This paper suggests the design standard of winding number of stator for high efficiency. And this paper shows the experimental results of driving performance of SRM.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2002.10a
• /
• pp.112-119
• /
• 2002

In this paper, an Extended Finite Element Method is proposed by adding discontinuity and singularity enrichment functions to the standard FEM approximation. In this method, the singularity and the discontinuity of the crack are efficiently modeled by using initial regular mesh without refining mesh near the crack tip, so that it enables express the asymptotic stress field near crack tip and crack surface successfully. The developed method was verified by evaluating crack tip stress profile and stress intensity factor of mode Ⅰ/mode Ⅱ fracture problems and the results showed the effectiveness and robustness for fracture problem.

• Environmental Analysis Health and Toxicology
• /
• v.11 no.1_2
• /
• pp.49-57
• /
• 1996

The production of reactive oxygen species on addition of hexavalent chromium (potassium dichromate, $K_2Cr_2O_7$ ) to lung cells in culture was studied using flow cytometer analysis. A Coulter Epics Profile flow cytometer was used to detect the formation of reactive oxygen species after $K_2Cr_2O_7$ was added to A549 cells grown to confluence. The cells were loaded with the dye, 2',7'-dichlorofluorescein diacetate, after which cellular esterases removed the acetate groups and the dye was trapped intracellularly. Reactive oxygen species oxidized the dye, with resultant fluorescence. Increased doses of Cr(VI) caused increasing fluorescence (10-fold higher than background at 200 gM). Addition of Cr(III) compounds, as the picolinate or chloride, caused no increased fluorescence. Electron paramagnetic resonance (EPR) spectroscopic studies indicated that three (as yet unidentified) spectral "signals" of the free radical type were formed on addition of 20, 50, 100 and 200 gM Cr(VI) to the A549 cells in suspension. Two other EPR 'signals" with the characteristics of Cr(V) entities were seen at field values lower than the standard free radical value. radical value.

• International Journal of Fluid Machinery and Systems
• /
• v.4 no.1
• /
• pp.133-139
• /
• 2011

In this paper, Based on Two-dimensional Flow Theory, adopting quasi-orthogonal method and point-by-point integration method to design the impeller of the low specific speed centrifugal pump by code, and using RANS (Reynolds Averaged N-S) Equation with a standard k-${\varepsilon}$ two-equation turbulence model and log-law wall function to solve 3D turbulent flow field in the impeller of the low specific speed pump. An analysis of the influences of the blade profile on velocity distributions, pressure distributions and pump performance and the investigation of the flow regulation pattern in the impeller of the centrifugal pump are presented. And the result shows that this method can be used as a new way in low speed centrifugal pump impeller design.

• The korean journal of orthodontics
• /
• v.15 no.2
• /
• pp.313-325
• /
• 1985

This study was performed to establish the cephalometric standards and growth change of Korean teen-age group by Ricketts analysis. A roentgenocephalometric study was made from 365 subjects, that consist of 159 males, 206 females with normal occlusion, acceptable profile and no history of orthodontic and prosthodontic treatment. The results were as follows: 1. The tables of means, standard deviation from measured values were made. (male, female, both sex). 2. The tables of regression equations from measured values were made to establish the relationship between age and each item. (male, female, both sex). 3. All linear measurements of each item in male were greater than in females. 4. Items which show more linear than any other items were condyle axis, facial axis length, corpus length and upper molar position.

• Journal of the Korean Chemical Society
• /
• v.57 no.2
• /
• pp.227-233
• /
• 2013

A series of newer substituted-imidazolidine derivatives 3a-k were synthesized and assayed in vivo to investigate their anti-inflammatory, analgesic and antiulcer activity. The results of biological evaluation revealed that the three compounds, 4-[1,3-bis(4-hydroxy-3-methoxybenzyl)-2-imidazolidinyl]phenyldiethylamine (3g), 4-[1,3-bis(3-Ethoxy-4-hydroxybenzyl)-2-imidazolidinyl] phenyldiethylamine (3h) and 4-(1,3-bis(benzo[d][1,3]dioxol-5-ylmethyl)-4-methylimidazolidin-2-yl)-N,N-diethylbenzenamine (3j) were good in their anti-inflammatory and analgesic actions. Additionally these derivatives showed superior GI safety profile as compared to that of the standard drug in terms of low severity index. The results are statistically treated for its significance.

• Proceedings of the KSR Conference
• /
• 2002.05a
• /
• pp.220-227
• /
• 2002

Now, Korea National Railroad is planning many ways to increase the maximum operating speed of train up to 200km/h by 2010. Among those ways, connecting conventional line with the KTX is the strongest alternative. Mostly, conventional lines are consisting of both KS50N and KS6O rail. However, the excessive abrasion might be occurred between wheel and rail when the KTX designed to operate on UIC60 is operating on the conventional line. On this study, new standard of 60kg-class rail considered suitability for both KTX and wheel used in conventional line is presented. It seems to be an effective solution for increasing maintenance costs expected when commercial speed of conventional line is increasing.

• Proceedings of the KSR Conference
• /
• 2005.11a
• /
• pp.394-399
• /
• 2005

Embedded rail track can be described as a track structure that is completely covered within pavement. Rail supported continually on a concrete slab or concrete plinth. There are many kinds of types such as non-resilient track and resilient track, super resilient embedded track (floating slab). Embedded rail track is generally the standard for light rail transit routes because this track has many advantages such as reducing noise, maintenance cost and weight of track. In this paper, decision of track profile is restricted by the optimum levels of the flangeway and the gap between the rail head and the pavement surface of depressing tread zone. By result of this study, embedded rail track can reduce corrosion of rail, internal stress and rail deflection.

• Proceedings of the ESK Conference
• /
• 1993.04a
• /
• pp.49-57
• /
• 1993

국가기간전산망의 주전산기의 사용자 인터페이스의 표준화는 사용자와 개발자들에게 일관성 있도 호환성 있는 환경을 제공하여 사용자와 개발자의 생산성을 향샹시키는 것을 목적으로 한다. 표준 사용자 인터페이스에 의한 일관성 있는 사용자 인터페이스는 한번 익숙해지면 사용자가 쉽게 다른 응용프로그램을 사용할 수 있도록 해주며, 표준 응용프로그램 인터페이스(Application Program Interface: API)는 응용프 로그램의 이식성을 향상시켜 개발자의 생산성을 높인다. 본 연구는 주전산기의 사용자 인터페이스중에서 특히 국제적으로 표준화가 활발히 진행되고 있는 그래픽 사용자 인터페이스(Graphical User Interface: GUI)를 우리 환경에 맞게 지원하기 위하여 필요한 표준규약을 정한다. 이 표준규약은 분산환경 혹은 네트워크를 지원 하는 국가기간전산망 주전산기의 비트맵(Bitmap) 그래픽 사용자 인터페이스에 적용되는 것을 목적으로 한다.

• Journal of the Korea Society of Computer and Information
• /
• v.21 no.9
• /
• pp.157-163
• /
• 2016

In this paper, I had studied to focus on the NCS(National Competency Standard) course in the development process of NCS-based curriculum and designed and developed 'Digital Color Correction' course. 'Digital Color Correction' course was come up with in process of development of NCS-based curriculum in a department of university that aims to educate video-broadcasting experts who lead the advanced digital age. The course developed in this paper follows criteria of NCS and is designed to step in course-profile, instruction and evaluation. Also I made an analysis of learning effects after applying to class. And I compared and analyzed NCS-class and non NCS-class. As a result of comparison, NCS-class is better than non NCS-class in student attitude for learning and evaluation method.