• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.3
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• pp.347-353
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• 1995

[ $F_o-value$ ] of canned smoked-oyster in cottonseed oil (SOCO) were measured using a microcomputer aided $F_o-value$ measuring system, and the microbiological safety of the canned SOCO was evaluated to optimize the energy consumption. Most of the microorganisms in raw oyster were saprophytes. No microorganisms were detected from the canned SOCO which was pretreated by conventional procedure and sterilized at $110^{\circ}C$ with $F_o-value$ of 5.92min and over. The most heat resistant microflora isolated from the raw oyster was Bacillus sp.. D-value at $121.1^{\circ}C$ and z-value of spores of Bacillus sp. in the SOCO homogenate were 4.10min and $10,91^{\circ}C$, respectively. After 120 days storage at $50^{\circ}C$, no growth of microorganisms was recognized from the canned SOCO with $F_o-value$of 5.92min.

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3317-3320
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• 2012

A novel energetic compound, bifurazano[3,4-b:3',4'-f]furoxano[3'',4''-d] oxacyclohetpatriene (BFFO), was synthesized through special etherification and its structure was determined by single crystal X-ray diffraction. The crystal of $BFFO{\cdot}H_2O$ is monoclinic, space group P2(1)/c with crystal parameters of a = $9.324(4){\AA}$, b = $9.727(4){\AA}$, c = $10.391(4){\AA}$, ${\beta}=106.305(6)^{\circ}$, V = $904.5(6){\AA}^3$, Z = 4, ${\mu}=0.17mm^{-1}$, F(000) = 512 and $D_c=1.866g\;cm^{-3}$. Spectroscopic properties and thermal behaviors of BFFO were studied. BFFO presents good detonation properties.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.157-162
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• 1998

양전자 단층 촬영장치(PET)에 사용되는 주요 양전자 방출 핵종들의 생성 단면적을 평가하였다. 평가한 생성 반응들은 $^{14}$ N(p,$\alpha$)$^{11}$ C,$^{16}$ O(p,$\alpha$)$^{13}$N, $^{14}$ N(d,n)$^{15}$ O,$^{18}$ O(p,n)$^{18}$ F,$^{20}$ Ne(d,$\alpha$)$_{18}$ F 이며, 입사 입자의 에너지 범위는 반응 문턱 에너지부터 약 150 MeV까지이다. 또한 하전입자 범 모니터용 표준 단면적으로서 $^{27}$ Al에 d 및 $^3$He, $\alpha$가 반응하여 $^{22}$ Na가 생성되는 반응의 단면적들을 입사 에너지 약 120 MeV까지 평가하였다. 실험치를 fitting하게나 ALICE95 코드를 이용하여 이론적 계산을 수행하였는데, 평가 단면적의 표준 편차는 10-30%이다 이들 평가 단면적들은 가속기를 이용한 PET용 핵종의 생산율 계산 및 빔 모니터의 표준 단면적으로 사용하기에 적절한 것으로 판단된다.

• Journal of Magnetics
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• v.2 no.2
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• pp.35-37
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• 1997

A sample of YBa2Cu3O7-x fluorinated by a high temperature (400$^{\circ}C$) gas exchange technique has been investigated by means of 19F NMR (nuclear magneti resonance) measurements in both superconducting and normal state. As a result, behaviors characteristic of the superconductor, including a peculiarity in the spin-lattice relaxation rate (1/T1) around 250 K, were observed.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.3
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• pp.1-8
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• 1999

Mixing efficiency of the unlike Impinging split triplet injector(FOOF type) were measured to investigate the effect of the momentum ratio variation. $H_2$O/kerosene were used as a propellant simulant. The maximum mixing efficiency occured at the momentum ratio 1.5 (total mixture ratio 1.89). Calculated mixing efficiency of real propellant LOX/Kerosene showed similar trend but maximum efficiency of characteristic velocity occurs at the momentum ratio 2.0(total mixture ratio 2.17). Although there exist a little discrepancy between calculated mixing efficiency based on simulant cold test and hot fire test results, this calculated mixing efficiency can be used to predict hot fire mixing efficiency.

• Wind and Structures
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• v.38 no.1
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• pp.59-74
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• 2024

Large Eddy Simulation (LES) is used to explore the influence of vibration frequency and amplitude on the aerodynamic performance of a rectangular cylinder with an aspect ratio of B/D=5 (B: breadth; D: depth of cylinder) at a Reynolds number of 22,000 near resonance frequency. In smooth flow conditions, the research employs a sequence of three-dimensional simulations under forced vibration with diverse frequency ratios f_e / f_o = 0.8-1.2 (f_e : oscillation frequency; f_o : Strouhal frequency when the rectangular cylinder is stationary ) and oscillation amplitudes A_h/D = 0.05 - 0.3. The individual influences of f_e / f_o and A_h/D on the characteristics of integrated and distributed aerodynamic forces are the focal points of discussion. For the integrated aerodynamic force, particular emphasis is placed on the analysis of the dependence of velocity-proportional component C₁ and displacement-proportional component C₂ of unsteady aerodynamic force on amplitude and frequency ratio. Near the resonance frequency, the dependencies of C₁ and C₂ on amplitude are stronger than that of frequency ratio. For the distributed aerodynamic force, the increase in frequency and amplitude promotes the position of the main vortex core and reattachment to the leading edge in the streamwise direction. In the spanwise direction, vibration enhances the spanwise correlation of aerodynamic force to weaken the three-dimensional effect of the flow field, and a lower frequency ratio and larger amplitude amplify this effect.

• Korean Journal of Crystallography
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• v.13 no.1
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• pp.25-30
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• 2002

The M/sub 1-x/Na/sub 2x/Al₂(BO₃)₂O (M = Ca and Sr) solid solution systems have been shown interstitial solid solutions and continuous substitutional solid solutions. The symmetry around the Eu site of yEu/sup 3+/ : M/sub 1-x/Na/sub 2x/Al/sub 2-y/Mg/sub /(BO₃)₂O (M = Ca and Sr) changes the intensities and the chromaticities of transitions. The Eu/sup 3+/ion can be very bright and efficient and have the desired emission wave-length depending on the site symmetry of the Eu/sup 3+/ion site. As the amount of Na in the Eu/sup 3+/ion doped Ca/sub 1-x/Na/sub 2x/Al₂(BO₃)₂O system increases, the Eu site symmetry is going to be a noncentrosymmetric site. With increasing x, the decreased intensity in the /sup 5/D/sub 0/→/sup 7/F₁(590 nm) transition relates to the low symmetry of the Eus/up 3+/-doped Ca/sub 1-x/Na/sub 2x/Al₂(BO₃)₂O system, because of the Ca-centered octahedron in the CaAl₂(BO₃)₂O compound. The SrAl₂(BO₃)₂O compound also provides an improved chromaticity due to the lower site symmetry of Eu/sup 3+/ion.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.3
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• pp.411-416
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• 1993

We assessed effects of ovine luteinizing hormone (oLH) and follicle-stimulating hormone (oFSH) on the granulose and theca layers from the four largest follicles, $F_1-F_4$ of hens which had been hypophysectomized 12 h before expected ovulation. Ovine LH (0.4 mg), oFSH (0.4 mg) or oLH in combination with oFSH (0.4 mg each) was injected intravenously 6 h after hypophysectomy. Progesterone, testosterone and $estradiol-17{\beta}$ levels of the granulose and theca layers which were removed 6 h after hormone injection, were measured by radioimmunoassay. Progesterone contents of $F_1-F_3$ granulosa layer at 12 h after hypophysectomy were much lower than those of control hens. This reduced progesterone level was restored partially by the injection of oLH alone for $F_1$, while no follicles responded to oFSH treatment. In contrast, the injection of oLH in combination with oFSH resulted in high progesterone content of the granulose layer from all four follicles. Progesterone content of the theca layer was negligible in all treatments. Simultaneous injection of oLH and oFSH also elevated $estradiol-17{\beta}$ level accumulating in the theca layer from all follicles, of which much higher concentrations of $estradiol-17{\beta}$ were observed when comparison were made to each of their corresponding controls. No appreciable change in testosterone contents of two layers was observed in the present experiments. These results suggest that oFSH augments function of oLH to stimulate the production of progesterone in the granulose layer and $estradiol-17{\beta}$ in the theca layer.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.104-104
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• 2000

MOS소자의 크기가 작아짐에 따라 gate 유전막의 두께 또한 얇아져야 한다. 두께가 얇아짐에 따라 gate 유전막으로써 기존의 SiO2는 direct tunneling으로 인해 높은 누설전류를 수반한다. 그래서 높은 유전상술르 가지는 물질들에 대한 연구의 필요성이 대두되고 있다. 그중 CVD-Ta2O5는 차세대 MOSFET소자기술에 있어서 높은 유전상수($\varepsilon$r+25)와 우수한 step coverage 때문에 각광을 받고 있는 물질중에 하나이다. 본 연구에서는 Ta2O5를 gate를 유전막으로 사용하고 RTN처리와 wet oxidation을 접목시켜 이들의 전기적인 특성을 향상시킬 수 있었다. p-형 wafer 위에 D2와 O2를 사용하여 SiO2(100 )를, NH3를 이용하여 Nitridation(10 )을 전처리로써 각각 실시하였고 그 위에 MOCVD방법으로 Ta2O5를 80 성장시켰다. 첫 번째 시편은 45$0^{\circ}C$ 10min동안 wet oxidation을 시켰고, 두 번째 시편은 $700^{\circ}C$ 60sec동안 NH3 분위기에서 RTN 처리를 하였다. 세 번째 시편은 동일조건으로 RTN 처리후 wet oxidation을 하였다. 그 후 각각의 시편을 capacitor를 제작하고 그 전기적 특성을 관찰하였다. Wet oxidation만을 시킨 시편은 as-deposited Ta2O5 시편에 비해서 -1.5V에서 누설전류는 약 2~3 order정도 감소되었고 accumulation 영역에서의 capacitance 값은 oxide층의 성장(5 )을 무시하면 거의 변화하지 않았다. RTN처리만 된 시편의 경우는 -1.5V에서 누설전류는 2~3order 정도 증가되었지만, accumulation 영역에서 capacitance 값은 거의 2qwork 증가하였다. 이 두가지 공정을 접목시킨 즉 RTN 처리후 wet oxidation 처리된 시편의 경우는 as-deposited Ta2O5 시편에 비해서 -1.5V에서 누설전류는 1 order 정도 감소하였고, accumulation 지역에서의 capacitance 값은 약 2배 증가하였다. 즉 as deposited Ta2O5 시편의 accumulation 지역의 capacitance 값은 12.8 fF/um2으로써 그 유효두께는 27.0 이었지만, RTN 처리후에 wet oxidation 시킨 시편의 accumulation 지역의 capacitance값은 21.2fF/um2으로써 그 유효두께는 16.3 이 되었다. 결론적으로 as deposited Ta2O5 시편에 RTN 처리후 wet oxidation을 실시한 결과 capacitance 값이 약 2배정도 증가하였고 누설전류는 약 1 order 정도 감소됨을 확인하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.989-999
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• 2006

In this paper, numerical analysis method to perform linear dynamic analysis of bridge considering the road surface roughness and bridge-vehicle interaction when vehicle is moving on bridge is presented. The vehicle and bridge are modeled as three-dimension where contact length of tire and pitching of tandem spring are considered and single truck with 2-axles and 3- axles, and tractor-trailer with 5-axles are modeled as 7-D.O.F., 8-D.O.F., and 14-D.O.F., respectively. Dynamic equations of vehicle are derived from the Lagrange's equation and solution of the equation is obtained by Newmark-${\beta}$ method. The surface roughness of bridge deck for this analysis is generated from power spectral density (PSD) function. Beam element for the main girder, shell element for concrete deck and rigid link between main girder and concrete deck are used. The equations of the motion of bridges are solved by mode-superposition procedures. The proposed procedure is validated by comparing the results with the experimental data by Whittemore and Fenves.