• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.8
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• pp.646-651
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• 1998

In this present study, the luminescence characteristics and mechanism of energy $CaTiO_3$:Pr phosphor were studied using disk specimens sintered at various temperatures and envirenment. A single-phase $CaTiO_3$:Pr was synthesized by sintering above 140$0^{\circ}C$ and its crystal structure was found to be perovskite orthorhombic. A dominant peak around 360 nm and a broad peak around 395 nm were observed in the PLE(Photoluminescence Excitation) spectrum of $CaTiO_3$:Pr with fixed emission wavelength at 612 nm, the decay time of 360 nm excitation was found to be longer than that of 395 nm excitation. From this result, it is assumed that the free carrier excited to 360 nm is transferred to 395 nm energy level. Therefore, the decrease in 395 nm intensity observed in CaTiO$_3$:Pr specimens sintered in Ar gas environment induced shorter decay time and improved CL luminescence.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.1
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• pp.36-45
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• 2000

Most researches for impinging jet spray have been focused on under-standing the breakup mechanism of a liquid sheet formed by the collision of jets and modeling the spray breakup using experimental data. For this reason, there have been few studies on the characteristics of the spatial spray distribution which affects significantly the combustion efficiency. Hence, we measured the radial distribution of fuel massflux using a like-doublet type injector. Instead of PDPA(Phase Doppler Particle Analyzer) which has been used only for the point measurement of the drop size of spray, PLIF(Planar Laser Induced Fluorescence) technique was developed lot the 2-D measurement of the massflux distribution of spray Indirect photography technique was also used to verify PLIF data.

• Journal of Life Science
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• v.10 no.2
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• pp.210-217
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• 2000

A kinetic profile of the catalytic domain of stromelysin-1 (SCD) using the fluorescent peptide substrate has been determined by the stopped-flow technique. The pH profile has a pH optimum of about 5.5 with an extended shoulder above pH 7. Three pKa values, 5.0, 5.7, and 9.8 are found for the free enzyme state and two pH independent Kcat/Km values of 4.1$\times$104 M-1 s-1 and 1.4$\times$104 M-1 s-1 at low and high pH, respectively. The profile is quite different in shape with other MMP family which has been reported, having broad pH optimum with two pKa values. The substrate specificity of SCD towards fluorescent heptapeptide substrates has been also examined by thin layer chromatography. The cleavage sites of the substrates have been identified using reverse-phase HPLC method.SCD cleaves Dns-PLA↓L↓WAR and Dns-PLA↓L↓FAR at two positions. However, the Dns-PLA↓LRAR, Dns-PLE↓LFAR, adn Dns-PLSar↓LFAR are cleaved exclusively at one bond. The double cleavages of Dns-PLALWAR and Dns-PLALFAR by SCD are in marked contrast to the close structurally related matrilysin. A notable feature of SCD catalysis agrees with the structural data that the S1' pocket of SCD is deeper than that of matriysin. The differences observed between SCD and matrilysin may form the basis of understanding the structural relationships and substrate specificities of the MMP family in vivo.

• Korean Journal of Materials Research
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• v.31 no.10
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• pp.582-585
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• 2021

Y₂O₃:Eu_x (x = 0.005, 0.01, 0.02, 0.03, 0.05, 0.1 mol) phosphors are synthesized with different concentrations of Eu³⁺ ions by solvothermal method. The crystal structure, surface and optical properties of the Eu doped Y₂O₃ phosphors are investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and photoluminescence (PL) and photoluminescence excitation (PLE) analyses. From X-ray diffraction (XRD) results, the crystal structure of the Eu doped Y₂O₃ phosphor is found to be cubic. The maximum emission spectra of the Eu doped Y₂O₃ phosphors are observed at 0.05 mol Eu³⁺ concentration. The photoluminescence of 615 nm in the Eu doped Y₂O₃ phosphors is associated with ⁵D₀ → ⁷F₂ transition of Eu³⁺ ions. The decrease in emission intensity of 0.1 mol Eu doped Y₂O₃ is interpreted by concentration quenching. The International Commission on Illumination (CIE) coordinates of 0.05 mol Eu doped Y₂O₃ phosphor are X = 0.6547, Y = 0.3374.

• Physical Therapy Rehabilitation Science
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• v.11 no.3
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• pp.370-375
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• 2022

Objective: The purpose of this study was to compare the hip joint muscle strength of patients with chronic back pain with lumbar instability and normal subjects. Design: A case control study. Methods: Five types of lumbar instability test were conducted on forty young women with chronic low back pain for more than six months, and those who had 3 or more positive tests were selected as subjects. To select chronic back pain patients with lumbar instability group, aberrant movement patterns during lumbar flexion test (FMT), prone instability test (PIT), posterior-anterior mobility test (PAT), passive lumbar extension test (PLE), and pressure bio-feedback (PBF) were applied. In addition, a digital muscle strength meter was used to measure the hip flexor, extensor, adductor, and abductor muscles of chronic low back pain patients with lumbar instability group (n=20) and normal subject group (n=20). Results: As a result of comparing the hip joint muscle strength between the chronic back pain patient group with lumbar instability and the normal group, there were significant differences in the hip extensor, abductor, and adductor muscles (p<0.05). Conclusions: Patients of chronic back pain with lumbar instability were found to have weak hip joint muscle strength. Therefore, this study suggest that include hip joint strength exercise for functional recovery of chronic back pain patients.

• Journal of Korean Academy of Nursing
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• v.45 no.2
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• pp.280-292
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• 2015

Purpose: In this study a system dynamics methodology was used to identify correlation and nonlinear feedback structure among factors affecting unplanned extubation (UE) of ICU patients and to construct and verify a simulation model. Methods: Factors affecting UE were identified through a theoretical background established by reviewing literature and preceding studies and referencing various statistical data. Related variables were decided through verification of content validity by an expert group. A causal loop diagram (CLD) was made based on the variables. Stock & Flow modeling using Vensim PLE Plus Version 6.0b was performed to establish a model for UE. Results: Based on the literature review and expert verification, 18 variables associated with UE were identified and CLD was prepared. From the prepared CLD, a model was developed by converting to the Stock & Flow Diagram. Results of the simulation showed that patient stress, patient in an agitated state, restraint application, patient movability, and individual intensive nursing were variables giving the greatest effect to UE probability. To verify agreement of the UE model with real situations, simulation with 5 cases was performed. Equation check and sensitivity analysis on TIME STEP were executed to validate model integrity. Conclusion: Results show that identification of a proper model enables prediction of UE probability. This prediction allows for adjustment of related factors, and provides basic data do develop nursing interventions to decrease UE.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2769-2773
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• 2013

Red phosphors $Ca_{(1-1.5x)}Eu_xWO_4$ and $Ca_{(1-2x)}Eu^_xNa_xWO_4$ were synthesized with various concentrations x of $Eu^{3+}$ ions by using a solid-state reaction method. The crystal structure of the red phosphors were found to be a tetragonal scheelite structure with space group $I4_1/a$. X-ray diffraction (XRD) results show the (112) main diffraction peak centered at $2{\theta}=28.71^{\circ}$, and indicate that there is no basic structural deformation caused by the vacancies ${V_{Ca}}^{{\prime}{\prime}}$ or the $Eu^{3+}$ (and $Na^+$) ions in the host crystals. Densities of $Ca_{(1-1.5x)}Eu_xWO_4$ were measured on a (helium) gas pycnometer. Comparative results between the experimental and theoretical densities reveal that $Eu^{3+}$ (and $Na^+$) ions replace the $Ca^{2+}$ ions in the host $CaWO_4$. Also, the photoluminescence (PL) emission and photoluminescence excitation (PLE) spectra show the optical properties of trivalent $Eu^{3+}$ ions, not of divalent $Eu^{2+}$. Raman spectra exhibit that, without showing any difference before and after the doping of activators to the host material $CaWO_4$, all the gerade normal modes occur at the identical frequencies with the same shapes and weaker intensities after the substitution. However, the FT-IR spectra show that some of the ungerade normal modes have shifted positions and different shapes, caused by different masses of $Eu^{3+}$ ions (or $Na^+$ ions, or ${V_{Ca}}^{{\prime}{\prime}}$ vacancies) from $Ca^{2+}$.

• Journal of the Korean Vacuum Society
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• v.16 no.3
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• pp.192-196
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• 2007

ZnSe/CdSe/ZnSe single quantum wells with different well thickness were grown by hot wall epitaxy. The quantum well thicknesses were measured by TEM. The critical thickness of single quantum well layer was found to be about $9{\AA}$ from the intensities and the full-width at half maximum of photoluminescence(PL) spectra. When the thickness of quantum wells was less than the critical thickness, the Stoke's shift was confirmed from the comparison between PL and photoluminescence excitation spectra, and it may be due to the exciton binding energy. The PL peak energy dependence on the quantum well thickness was coincident with the theoretical values.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.2
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• pp.76-82
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• 1997

In paper the evenness of planar distribution of mass in a small scale is called formation (orbetter:mass formation). Traditionally formation has been assessed visually, by looking the sheet of paper against transmitted light. Different kinds of optieal testers are being usd to obtain quantitative rankings htat would be independent of the observer but would well correspond to the visual assessment. However, various raw-material and process factors do influence light trans-mittance in paper and do impair the correspondence between basis weight and the optical formation measurement (or visual assessment). As the optical formation test methods do not incorporate an efficient calib ration routine, the formation of the sophisticated paper grades of today the is rather difficult to measure optically and may lead to erroneous results. It may be concluded that the optical measurement is not suitable for paper grades with high filler content. coating, heavy calendering or that are made of heavily beaten pulp, nordoes it apply for dyed or printed papers. For this reason, visual assessment and optical evaluation shoild be replaced with a measurement that gives reliable results independent on paper grode and manufacturing process. Formation measuremend based on beta radiation is suitable for all paper grades regardless to the material contents or process treatment. It is possible to measure even dyed or printed samples. Thonks to a sim ple and relioble calibration, the results are converted to real basis weight balues that remain reliable even with time. The only beta tester commercially available is the AMBERTEC Beta Formation Tester. Formation of paper does vary locally in the web. Typically there exists a formation profile, too similarly to other properties of paper. Therefore, formation should ？ ays be expressed as a mean of a sufficient amount of parallel determinations. All formation measurements should be calibrated against basis weight.

• Archives of Pharmacal Research
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• v.27 no.9
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• pp.901-905
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• 2004

A rapid, sensitive and selective hydrophilic interaction liquid chromatography-tandem mass spectrometric(HILIC-MS/MS) method for the determination of tiapride in human plasma was developed. Tiapride and internal standard, metoclopramide were extracted from human plasma with dichloromethane at basic pH and analyzed on an Atlantis HILIC silica column with the mobile phase of acetonitrile-ammonium formate (190 mM, pH 3.0) (94：6, v/v). The ana-Iytes were detected using an electrospray ionization tandem mass spectrometry in the multi-ple-reaction-monitoring mode. The standard curve was linear (r＝0.999) over the concentration range of 1.00-200 ng/mL. The coefficient of variation and relative error for intra- and inter-assay at three QC levels were 6.4∼8.8％ and -2.0∼3.6％, respectively. The recoveries of tiapride ranged from 96.3 to 97.4％, with that of metoclopramide (internal standard) being 94.2％. The lower limit of quantification for tiapride was 1.00 ng/mL using 1 00 $\mu$L of plasma sample.