• Bulletin of the Korean Chemical Society
• /
• v.29 no.10
• /
• pp.1973-1976
• /
• 2008

Electronic photodepletion spectrum of dibenzo-18-crown-6 with a potassium ion ($K^+$-DB18C6) was obtained in the gas phase using electrospray ionization and quadrupole ion-trap reflectron time-of-flight mass spectrometry. The spectrum exhibited rather a broad absorption band at 36350 $cm^{-1}$, which was tentatively assigned as the origin of the S1 band. The photodepletion spectrum of $Cs^+$-DB18C6 was also obtained to elaborate the effects of metal cations on electronic and geometric structures of metal cation-DB18C6 complexes. We found that the S1 band of $Cs^+$-DB18C6 was red-shifted by 180 $cm^{-1}$ from that of $K^+$-DB18C6. With the results of quantum theoretical calculations using the density functional theory, we suggested that the red-shift arose mainly from weaker binding of $Cs^+$ to DB18C6 than that of K+, which resulted from a larger size of $Cs^+$ than that of the cavity in DB18C6.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.11a
• /
• pp.498-498
• /
• 2001

Seismic qualification of the Main Control Boards for nuclear power plants has been performed with the guideline of AS ME Section III. US NRC Reg. Guide and IEEE 344 code. The analysis model of the Main Control Boards is consist of beam. shell and mass element by using the finite element method. and, at the same time. the excitation forces and other operating loads for each model are encompassed with respect to different loading conditions. As the fundamental frequencies of the structure are found to be less than 33Hz. which is the upper frequency limit of the seismic load, the response spectrum analysis using ANSYS is performed in order to combine the modal stresses within the frequency limit. In order to confirm the structural and functional integrity of the major components, modal analysis theory is adopted to derive the required response spectrum at the component locations. As all the combined stresses obtained from the above procedures are less than allowable stresses and no mechanical or electrical failures are found from the seismic testing, it concludes the Main Control Boards is dynamically qualified for seismic conditions. Although the authors had confirmed the structural and functional integrity of both Main Control Boards and all the component, in this paper only the seismic analysis of the Main Control Board is introduced.

• Earthquakes and Structures
• /
• v.17 no.5
• /
• pp.477-487
• /
• 2019

Understanding the behavior of skew bridges under the action of earthquakes is quite challenging due to the combined transverse and longitudinal responses even under unidirectional hit. The main goal of this research is to assess the response of skew bridges when subjected to longitudinal and transversal earthquake loading. The effect of skew on the response considering two- and three- span bridges with skew angles varying from 0 to 60 degrees is illustrated. Various pier fixities (and hence stiffness) and cross-section shapes, as well as different abutment's bearing articulations, are also studied. Finite-element models are established for modal and seismic analyses. Around 900 models are analyzed under the action of the code design response spectrum. $Vis-{\grave{a}}-vis$ modal properties, the higher the skew angle, the less the fundamental period. In addition, it is found that bridges with skew angles less than 30 degrees can be treated as straight bridges for the purpose of calculating modal mass participation factors. Other monitored results are bearings' reactions at abutments, shear and torsion demand in piers, as well as deck longitudinal displacement. Unlike straight bridges, it has been typically noted that skew bridges experience non-negligible torsion and bi-directional pier base shears. In a complementary effort to assess the accuracy of the conducted response spectrum analysis, a series of time-history analyses are applied under seven actual earthquake records scaled to match the code design response spectrum and critical comparisons are performed.

• Proceedings of the KAIS Fall Conference
• /
• 2002.11a
• /
• pp.178-180
• /
• 2002

In this Paper, we conducted a experimental study to measure a particle size distribution and mass spectrum with the special instrument such as ISPM and Q-MS. Also, we set up a total measuring system for monitoring the particle in the process chamber.

• Proceedings of the Optical Society of Korea Conference
• /
• 2005.02a
• /
• pp.290-291
• /
• 2005

We have presented a comprehensive effective-mass Hamiltonian for strained Wurtzite semiconductors using k${\cdot}$p method and Kane's model. This theoretical groundwork provides a foundation for investigating the electrical and optical properties of wurtzite strained quantum-well lasers.

• 대한방사선방어학회:학술대회논문집
• /
• 2009.04a
• /
• pp.152-153
• /
• 2009

• Journal of the Earthquake Engineering Society of Korea
• /
• v.9 no.6 s.46
• /
• pp.13-19
• /
• 2005

Floor response spectra for dynamic response of subsystem such as equipment, or piping in nuclear power plants are usually generated without considering dynamic interaction between main structure and subsystem. This study describes the analytic method in which equipment response spectra can be obtained through dynamic analysis considering equipment-structure Interaction(ESI). In this method, dynamic response of the equipment by this method is based on a dynamic substructure method in which the equipment-structure system is partitioned into the single-degree-ol-freedom system(SDOF) representing the equipment and the equipment support impedance representing the dynamic charactenstics of the structure ai the equipment support. A family of equipment response spectra is developed by applying this method to calculate the maximum responses of a family of SDOF equipment systems with wide banded equipment frequency, damping ratio, and mass. The method is validated by comparing the floor response spectrum from this method with the floor response spectrum generated from the rigorous analysis including equipments on the containment building of a prototypical nuclear power plant. in order to Investigate ESI effect in the response of equipment, response values from the method and the conventional approach without considering ESI are compared for the equipment having the mass less than 1% of the total structural mass. Response spectra from the method showed lower spectral amplitudes than those of the conventional floor response spectra around controlling frequencies.

• Journal of Sericultural and Entomological Science
• /
• v.49 no.1
• /
• pp.8-13
• /
• 2007

Natural indigo colorants were prepared by extraction of Polygonum tinctorium which was harvested just in the blooming season(in the late of July). The components were analyzed by TLC and HPLC, and its structures were analyzed by FT-IR, EI-mass. The results obtained are summarized as follows; The natural indigo powder was dissolved in DMSO and developed in eluent, $CHCI_3/CH_3CN$(8.5:1.5 v/v) by means of TLC for its quality analysis. It was segregated into indirubin as a red colour and indigo as a blue colour. In case of HPLC analysis,. FT-IR spectrum of indirubin showed a peak for NH residue between 3200 and $3300cm^{-1}$. $^1H-NMR$ spectrum for indigo displayed AA'BB' spin system caused by indole structure between 6.5 and 7.7ppm of H4, 5, 6 and 7, and -NH proton for indirubin showed an singlet between 10.88 and 11.0ppm. EI-mass spectrum of indigo and indirubin both disclosed their molecular size as 262 and it implies that these two substances are isomer.

• Korean Journal of Pharmacognosy
• /
• v.41 no.4
• /
• pp.303-307
• /
• 2010

To overcome the limit of morphological method for classification of herbal drug, a novel method to discriminate its origin using pyrolysis mass spectrometry-multivariate analysis was developed. This method was applied successfully to Scutellaria baicalensis Georgi, one of the most popular herbal drug in oriental countries. The ethylacetate soluble fractions were prepared by sonication from pulverized roots of S. baicalensis which were collected from various regions including Korea and China, and subjected to direct insertion probe (DIP) mass spectrometry to achieve mass spectra of pyrolizates of extracts. The probe temperature was elevated from $30^{\circ}C$ to $320^{\circ}C$ at increasing rate $64^{\circ}C/min$, and the average mass spectrum calculated from total ion chromatography (TIC) was obtained. The relative peak intensities versus m/z were subjected to SAS program, and the training set (9 from Korea origin and 22 from China origin) was clustered two groups as its origin. In the test set, 11 samples among total 13 test sample were successfully classified according to their origin by developed method with accuracy of 85%.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2007.11a
• /
• pp.293-296
• /
• 2007

Using the T3 free-piston shock tunnel in ANU, the cavity frequency and flow characteristics of no mass-injection, inclined mass-injection before the cavity, parallel or reverse mass-injection in the cavity are investigated in the case of Mach 3.7 inflow condition. No mass-injection doesn't have the harmonic frequencies but has high amplitude of pressure spectrum at 10 kHz. Inclined mass-injection attenuates the cavity flow fluctuation as disturbing the shear layer reflection at the trailing edge. Parallel mass-injection flow reflects at the trailing edge of the cavity directly hence, increases the cavity flow fluctuation at high injection pressure.