• Journal of The Korean Astronomical Society
• /
• v.4 no.1
• /
• pp.9-16
• /
• 1971

The asymmetry of received intensity pattern within the bandwidth is derived from the analogy of the intensity distribution of two-slit interference. This suggests that the length of $\frac{1}{2}{\lambda}$ delay line should be adjusted to the slightly upper frequency than the central frequency of the radio telescope with a wide bandwith. Some strange communication signals and man-made noises prevented us from obtaining the discernible information from the observed data for the sun. To overcome this difficulties, it is necessary to alter the operating frequency and site. It will be fo1lowed to measure the angular dimensions of the superposed radio sources by changing the distance between two antennas.

• Publications of The Korean Astronomical Society
• /
• v.14 no.2
• /
• pp.79-81
• /
• 1999

We have made an extensive mapping of the $^{13}CO$ J=1-0 transition line in the dark cloud L1535. We also constructed the $100{\mu}m$ IRAS map in the region. We found a semi-detached cloud component of $^{13}CO$ in the northeast direction of the $^{13}CO$ main cloud which forms a dumbbell-like structure. This additional component with an angular size of $20'\times16'$ has not been observed before in any molecular surveys of the cloud. The IRAS map shows a similar structure with two intensity peaks whose positions coincide with those of the $^{13}CO$ clouds.

• Steel and Composite Structures
• /
• v.37 no.2
• /
• pp.137-150
• /
• 2020

In this research work, the analytical rotating vibration for functionally graded shell with ring supports are restricted to some volume fraction laws based on Rayleigh-Ritz technique. The frequencies of functionally grade cylindrical shells have been investigated for the distribution of material composition of material with two kinds of material. Stability of a cylindrical shell depends highly on these aspects of material with ring supports. The frequency behavior is investigated with fraction laws versus circumferential wave number, length-to-radius and height-to-radius ratios. The frequencies are higher for higher values of circumferential wave number. The frequency first increases and gain maximum value with the increase of circumferential wave mode. Moreover, the effect of angular speed is also investigated. It is examined that the backward and forward frequencies increases and decreases on increasing the ratio of height- and length-to-radius ratios.

• Journal of Magnetics
• /
• v.10 no.4
• /
• pp.133-136
• /
• 2005

The NiMn/NiFe bilayer structure which was short time annealed in order to induce unidirectional anisotropy were studied as a function of annealing temperature. The maximum exchange bias field of NiMn/NiFe bilayer was presented at $250^{\circ}C$ after short time annealing process with no external field. The appearance of exchange bias was due to phase transformation of NiMn layer. In plane angular dependence of a resonance field distribution which measured by FMR was analysed as a combined effect of unidirectional anisotropy and uniaxial anisotropy. The resonance field and the line width from FMR measurement were also analysed with annealing temperature.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.31-32
• /
• 2007

In this paper, a fault section detection method is proposed for ungrounded system in the case of a single line-to-ground fault. A conventional method is used for faulted feeder selection according to the angular relationship between zero-sequence currents of the feeders and zero-sequence voltage of the system. Fault section detection is based on the comparison of phase angle of zero-sequence current. Proposed method has been testified in a demo system by Matlab/Simulink simulations. Based on Distribution Automation System(DAS), Feeder Remote Terminal Unit(FRTU) is used to collect those necessary data, at present a demo system is under developing using Manufacturing Message Specification (MMS) in IEC61850 standard.

• Proceedings of the KIEE Conference
• /
• 1995.07a
• /
• pp.18-20
• /
• 1995

This paper describes a 7.5T magnetic flux density superconducting wiggler that minimize net angular deflection and displacement of an electron rotating along the orbit at storage ring in Pohang Light Source. It consist of dipole superconducting magnet,high uniformity flux distribution due to current source supply,cryostat,vacuum chamber,measurement system. In this paper magnet design procedure, manufacturing, experimental results are contained.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.6
• /
• pp.131-138
• /
• 2004

The objective of this paper is to decide optimal location of a pin-hole to minimize stress concentration around the hole in a rotating disc. The focus of this investigation is to evaluate the effect of pin-hole on stress distribution around the hole using optimum design technique and finite element analysis. Design variables are the radial and the angular location of pin-hole from center of the hole and objective function is the maximum stress around hole in a rotating disc. Using first order method of optimization technique, we found that the maximum equivalent stress around the hole with optimized pin-hole could be reduced by 15.1% compared to that without pin-hole.

• Advances in materials Research
• /
• v.8 no.2
• /
• pp.83-102
• /
• 2019

The present research deals with the time harmonic deformation in transversely isotropic magneto thermoelastic solid with two temperature (2T), rotation and without energy dissipation due to inclined load. Lord-Shulman theory has been formulated for this mathematical model. The entire thermo-elastic medium is rotating with a uniform angular velocity. The Fourier transform techniques have been used to find the solution to the problem. The displacement components, stress components and conductive temperature distribution with the horizontal distance are computed in the transformed domain and further calculated in the physical domain using numerical inversion techniques. The effect of time harmonic source and rotation is depicted graphically on the resulting quantities.

• Advances in materials Research
• /
• v.7 no.2
• /
• pp.105-118
• /
• 2018

Magnesium and its alloys are attracted towards all engineering applications like automotive, marine, aerospace etc. due to its inherent high strength to weight ratio. But, extensive use of Mg alloys is limited to the current scenario because of low wear and corrosion resistance behavior. However, equal channel angular press is one of the severe plastic deformation technique which has been effective method to improve the wear and corrosion resistance by achieving fine grain structure. In this study, the effect of grain refinement on wear and corrosion resistance of AZ80 Mg alloys were investigated. The wear behavior of the coarse and fine-grained Mg alloys was examined through $L_9$ orthogonal array experiments in order to comprehend the wear behavior under varies control parameters. It was shown that ECAPed alloy increased the wear and corrosion resistance of the Mg alloy through the formation of fine grain and uniform distribution of secondary ${\beta}-phase$. Also, the performance of AZ80 Mg alloy for these changeswas discussed through SEM morphology.

• Coupled systems mechanics
• /
• v.9 no.6
• /
• pp.521-538
• /
• 2020

The present study is concerned with the thermoelastic interactions in a two dimensional homogeneous, transversely isotropic thermoelastic solid with new modified couple stress theory without energy dissipation and with two temperatures in frequency domain. The time harmonic sources and Hankel transform technique have been employed to find the general solution to the field equations.Concentrated normal force, normal force over the circular region, thermal point source and thermal source over the circular region have been taken to illustrate the application of the approach. The components of displacements, stress, couple stress and conductive temperature distribution are obtained in the transformed domain. The resulting quantities are obtained in the physical domain by using numerical inversion technique. Numerically simulated results are depicted graphically to show the effect of angular frequency on the resulted quantities.