• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1393-1396
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• 2006

The 1+1 two-photon Resonant Enhanced Multiphoton Ionization (REMPI) spectra of 1,4-dichlorobenzene was obtained from 240 nm through to 250 nm on a laser mass spectrometer. Special care was taken to build up a heatable sample inlet system suitable for detecting a trace semi-volatile organic compound and reducing the memory effort on the inner wall of the inlet system. The detection limits of 1,4-dichlorobenzene in ppbV/V concentration range at certain wavelengths are presented.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.496-505
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• 2000

A semi-infinite parallel crack propagated with constant velocity in two bonded anisotropic strip under anti-plane clamped displacement is analyzed. Using Fourier integral transform a Wiener-Hopf equation is derived. By solving this equation the asymptotic stress and displacement fields near the crack tip are determined, where the results give the more general expression applicable to the extent of the anisotropic material having one plane of elastic symmetry for the parallel crack. The dynamic stress intensity factor and energy release rate are also obtained as a closed form, which are the results applicable to the problem both of dynamic and static crack under the same geometry as this study. The stress intensity factor approaches zero at the critical crack velocity which is less than the shear wave velocity, but in typical case of isotropic or orthotropic material agrees with the velocity of shear wave. Also a circular shear stress around crack tip is considered, from which the stress is shown to be approximately symmetric about the horizontal axis. Referring to the maximum stress criteria, it could be shown that a brenched crack is formed by crack growth as crack velocity increases.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.5
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• pp.697-704
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• 2003

In this paper, the visual tracking system for arbitrary shaped moving object is proposed. The established tracking system can be divided into model based method that needs previous model for target object and image based method that uses image feature. In the model based method, the reliable tracking is possible, but simplification of the shape is necessary and the application is restricted to definite target mod el. On the other hand, in the image based method, the process speed can be increased, but the shape information is lost and the tracking system is sensitive to image noise. The proposed tracking system is composed of the extraction process that recognizes the existence of moving object and tracking process that extracts dynamic characteristics and shape information of the target objects. Specially, active contour model is used to effectively track the object that is undergoing shape change. In initializatio n process of the contour model, the semi-automatic operation can be avoided and the convergence speed of the contour can be increased by the proposed effective initialization method. Also, for the efficient solution of the correspondence problem in multiple objects tracking, the variation function that uses the variation of position structure in image frame and snake energy level is proposed. In order to verify the validity and effectiveness of the proposed tracking system, real time tracking experiment for multiple moving objects is implemented.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.6 s.177
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• pp.1565-1574
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• 2000

Surface edge crack subjected to contact stresses is analysed. A punch with corner radii is considered to press the semi-infinite plane. Partial slip problem is solved when a shear force is applied to the punch. Dislocation density function method is used to solve the present mixed mode crack problem. The crack length of positive K1 is examined, which is affected by the ratio of the flat portion to the total width of the punch. Surface traction during one cycle of the shear force is evaluated to simulate the fretting condition. The compliance change of the contact surface is also investigated during the shear cycle. It is found that the crack grows during only a part of the cycle, which may be termed as effective period of crack growing. A design method for restraining the fretting failure is discussed, from which recommendable geometry of the punch is suggested.

• Environmental Analysis Health and Toxicology
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• v.22 no.2 s.57
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• pp.177-184
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• 2007

Gaseous organochlorine pesticides (OCPs : heptachlor epoxide, p, p'-DDE, ${\gamma}-HCH,\;{\alpha}-chlordane,\;{\gamma}-chlordane$ and trans-nonachlor) concentration was measured using PUF high volume sampler from June, 2000 to June, 2002 in the semi-rural atmosphere. The OCPs concentration in atmosphere, which is estimated by the slope (m) of Clausius-Clapeyron equation and phase-transition energy $({\Delta}H)$, was influenced by revolatilization from environmental matrix (soil, water and tree leaves) and a long range transportation of air mass. But the former affected OCPs concentration more than the latter. The degradation rate constants (k) of OCPs calculated using multiple regression analysis and revised standard temperature method were in good agreement each other. The value of k of ${\gamma}-HCH$ was very low as -0.0007, but the range of k of other components were $-0.00l8{\sim}-0.0038$. The half-life $({\tau})$ which was calculated by k of ${\gamma}-HCH$ was 2.6 years-the longest one, but that of heptachlor epoxide was in 0.5 year-the shortest one. $({\tau})\;of\;{\alpha}-chlordane,\;{\gamma}-chlordane$ and trans-nonachlor in technical chlordane was 1.0, 1.1 and 0.7 year respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.2
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• pp.220-228
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• 2008

Toluene adsorption characteristics in the adsorption bed packed with activated carbon fiber (ACF) were studied. Experimental apparatus is composed of VOC generation equipment, adsorption bed, and analytical instrument. Breakthrough characteristics were investigated with length of the adsorption bed which consisted of 3 or 5 sheets of the ACF and flow rate when toluene concentration are 400 ppm and 800 ppm respectively. When mass transfer zone (MTZ) comes out of the adsorption bed, toluene concentration is increased sharply and reached plateau region by saturation. Experimental results are compared with semi-empirical gas adsorption model proposed by Yoon and Nelson. In order to investigate the movement of the MTZ with adsorption time in the adsorption bed packed with ACFs, weight increment of each ACF was measured with the location of ACF at each run. When the weight increment of ACF by toluene adsorption which located at the exit of the bed reaches about 20%, toluene started to be detected.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.237-242
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• 2001

The stochiometric mix of evaporating materials for the CuGaSe$_2$ single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, CuGaSe$_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were 610$^{\circ}C$ and 450$^{\circ}C$, respectively The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the CuGaSe$_2$ single crystal thin film, we have found that the values of spin orbit splitting Δ So and the crystal field splitting ΔCr were 91 meV and 249.8 meV at 20 K, respectively. From the Photoluminescence measurement on CuGaSe$_2$ single crystal thin film, we observed free excition (Ex) existing only high quality crystal and neutral bound exiciton (D$^{\circ}$,X) having very strong peak intensity. Then, the full-width-at-half-maximum(FWHM) and binding energy 7f neutral acceptor bound excision were 8 meV and 35.2 meV, respectivity. By Haynes rule, an activation energy of impurity was 355.2 meV

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.101-102
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• 2006

A stoichiometric mixture of evaporating materials for $AgGaS_2$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films. $AgGaS_2$ mixed crystal was deposited on thoroughly etched semi-Insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were $590^{\circ}C$ and $440^{\circ}C$, respectively. The temperature dependence of the energy band gap of the $AgGaS_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=2.7284 eV-(8.695{\times}10^{-4} eV/K)T^2/(T+332 K)$. After the as-grown $AgGaS_2$ single crystal thin films was annealed in Ag-, S-, and Ga-atmospheres, the origin of point defects of $AgGaS_2$ single crystal thin films has been investigated by the photoluminescence(PL) at 10 K.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.1
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• pp.123-132
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• 1999

One of the major difficulties in the seismic analysis of a dam-reservoir system is the treatment of the energy radiation in the upstream direction of the reservoir. In the paper, a new transmitting boundary is presented that can model properly the radiation of energy in the far field direction of a semi-infinite reservoir with constant depth. In the newly developed method, effects of surface wave motion are taken into accounted and the reservoir-foundation interaction is approximately accounted for with an absorbing boundary condition. If a dam has vertical upstream face and the infinitely long reservoir maintains constant depth, then the proposed transmitting boundary can be directly coupled with the model of dam body. In present study, the dam body is assumed to behave elastically and modeled by finite element method. Seismic responses of a dam model are investigated using the newly developed transmitting boundary.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.2
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• pp.235-242
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• 1993

In order to investigate the effects of dietary cellulose and protein levels on chick performance, four semi-purified diets were formulated so as to contain cellulose at levels of 5% (LC) and 20% (HC) in combination with 10% (LP) and 20% (HP) protein, and fed ad libitum to 1-week-old White Leghorn male chicks for 3 weeks. There were no significant differences in feed intake, body weight gain and feed efficiency between the LC-HP and HC-HP groups. All parameters were lower in the LP groups; the HC-LP group consumed very small amount of feed and lost body weight during the experiment. The retention rates of DM, ash, nitrogen and energy were higher in the HP than the LP groups. The triglyceride concentration of carcass was lower in the HC-LP group and that of liver was higher in the LC-LP group. The carcass total cholesterol level was higher in the HC-HP group. The relative weight of most digestive organs was higher in the HP group irrespective of the cellulose level. In conclusion, the chick performance was primarily influenced by dietary protein level, and when the chicks were fed inadequate levels of protein, the low cellulose level gave a better performance than the high cellulose level.