• Journal of the Korean Vacuum Society
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• v.12 no.S1
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• pp.92-94
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• 2003

The sputtering yield change of an amorphous Si layer on Si(100) was measured quantitatively for 0.5 keV $O_2^{+}$ and $Ar^{+}$ ion bombardment with in suit MEIS. In the case of 0.5 keV $O_2^{+}$ ion bombardment, at the initial stage of sputtering before surface oxidation, the sputtering yield of Si was 1.4 (Si atoms/$O_2^{+}$) and then decreased down to 0.06 at the ion dose of $3\times10^{16}O_2\;^{+}\textrm{/cm}^2$. In the case of 0.5 keV $Ar^{+}$ ion bombardment, the sputtering yield of Si for the surface normal incidence was 0.56 at the ion dose of 2.5 ${\times}$ 10$^{15}$ $Ar^{+}\textrm{cm}^2$, and rapidly saturated to 1.2 at dose of $7.5\times10^{15}Ar^+\textrm{cm}^2$. For the incidence angle of 80 from surface normal, the sputtering yield of Si was saturated to about 1.4 at the initial stage of sputtering. The surface transient effects, caused by change in sputtering yield at the initial stage of sputtering can be negligible when 0.5 keV $Ar^{+}$ ion at extremely grazing angle was used for sputter depth profiling.g.

• Geomechanics and Engineering
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• v.24 no.1
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• pp.57-65
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• 2021

The effects of initial soil fabric and aspect ratio (AR) on the small-strain stiffness (G0) of granular soils are studied by employing discrete element method (DEM) numerical analysis. Elongated clumps composed of subspheres were adopted, and the G0 values were obtained by DEM simulations of drained triaxial tests under different densities and initial confining pressure (p0). The DEM simulations indicate that the initial soil fabric has an insignificant effect on G0. The effect of the AR on G0 is related to the initial density. Namely, for dense specimens, G0 first increases with increasing AR, reaching a plateau value when the AR ≥ 1.5. However, for loose specimens, G0 gradually increases as the AR increases. Microscopic examination reveals that G0 uniquely depends on the coordination number of the particles (CN-particle) rather than the subspheres (CN-sphere) at the particulate level for the effects of initial soil fabric and AR. Finally, Poisson's ratio ν0 is also determined by CN-particle. In addition, based on data in literature and this study, ν0 can be fitted as ν0 = 5.920(G0/(p0)1/3)-0.99, which can be used to predict ν0 of granular soils based on the measured G0.

• The Journal of Pediatrics of Korean Medicine
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• v.38 no.1
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• pp.78-87
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• 2024

Purpose To develop an educational program using virtual reality (VR) and augmented reality (AR) in oriental medicine education, this study investigated the status of programs currently being used mainly in the fields of medicine, nursing, and dentistry, and was the basis for developing an oriental medicine education program. We plan to use this for future research purposes. Methods To investigate medical simulation education using VR and AR technologies, 72 studies were searched using the ProQuest Central Database (period 1.1.2000 to 10.10.2023.) Of these, 22 were selected for analysis. Results Among the selected studies, the educational fields of the program were 59% (13 studies) in medicine, 32% (7 studies) in nursing, 9% (2 studies) in dentistry, 73% (16 studies) were VR in terms of applied technology, and 27% (6 studies) in AR. Conclusions Recently, research on VRand AR has increased in the medical field. As patient rights and medical environments change, clinical practice education programs using new technologies are needed, in addition to traditional face-to-face practice. Related research is expected to be active in the field of Oriental medicine in the future.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.1
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• pp.106-113
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• 2002

In this paper, breakdown characteristics of pure Kr, Ar and $N_2$gas with gas pressure range were investigated, and the measured values were compared with those in Ar/$N_2$and Kr/$N_2$gas mixtures with pressure varying. Also, various characteristics with gas mixtures in practical incandescent lamps were investigated. Summarizing the experimental results, the breakdown voltages of $N_2$gas were increased than those of Kr and Ar gas with large molecular weight, and the breakdown voltage increased with gas pressure increasing. The breakdown voltages of Ar/$N_2$and Ar/$N_2$gas mixtures were decreased with decreasing the mixtures ratio of $N_2$gas, and corona inception voltage of Kr/$N_2$gas mixtures under non-uniform fields were increased than those of Ar/$N_2$gas mixtures. In case of tactical incandescent lamps, luminous and lifetime of Kr(70%)/$N_2$(30%) gas mixtures were increased about 94[lm] and 380[hr] than those of Ar(70%)/$N_2$(30%) gas mixtures. and injection pressure of gas mixtures with cooling temperature of 20[$^{\circ}C$] in incandescent lamps were increased about 13[%] than those with cooling temperature of 40[$^{\circ}C$].

• Economic and Environmental Geology
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• v.19 no.2
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• pp.147-151
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• 1986

K-Ar ages on biotites have been determined from the Proterozoic Buncheon and Hongjesa granitic rocks in comparison with the Rb-Sr whole-rock ages to investigate the ages of metamorphic events. The Rb-Sr whole-rock ages determinations on the Buncheon and Hongjesa granitoid rocks were previously reported as 2,100Ma and 1,700Ma, respectively. K-Ar ages on biotites separated from the studied rock have revealed three different age groups such as 1) 1,200~1,300Ma, 2) 600~700Ma and 3) 300~400Ma. The Rb-Sr whole-rock ages for the granitic rocks represent the time of emplacement, whereas the K-Ar ages on biotites generally indicate the time of metamorphism or alteration. The large discordance in the two age systems may not be explained as indicating the cooling period of the granitic batholiths. The K-Ar ages on biotites from the granitoid rocks might not be simply interpreted as the age of the last phase of metamorphism, since the granitic rocks had been undergone multistages of amphibolite facies-metamorphism in the Precambrian period. During the multistages of intermediate grade metamorphism, $^{40}Ar$-loss could be inevitably taken place as the metamorphic temperatures went up above the blocking temperature of biotite ($300{\pm}50^{\circ}C$). The results of the K-Ar dating on biotites from this study are probably minimum ages or hydrothermal alteration ages.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.4
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• pp.1140-1146
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• 2004

This study was carried out to investigate the comparison of immunomodualtory effects of water-extracted Ginseng Radix(GR), Pilose Asia-bell(PA), Astragali Radix(AR), Astractylodes Rhizoma alba(AA) and Dioscoreae Rhizoma (DR). The parameter examined to assess apparent immunomodulatory effect of the water-extracted GR, PA, AR, AA and DR included the regulation of Nitric oxide (NO), the expression of Th1/Th2 type cytokine, the change of B cell phenotype. The water-extracted GR, PA, AR, AA and DR inhibited NO production and iNOS protein expression in LPS stimulated RAW 264.7 macrophage cells. In the Th1 and Th2 cytokine expression, the water-extracted GR, PA, AR, AA and DR induced IL-2 and IFNr mRNA gene expression. Therefore, it seems that the water-extracted GR, PA, AR, AA and DR have a inducing effect of Th1 type cytokines. In the Flow cytometry analysis, the water-extracted GR, PA, AR, AA and DR did not change B cell phenotype (CD45R/B220). The water-extracted GR, PA, AR, AA and DR have a reducing effect of immune suppression cause by Methotrexate (MTX), an agent of immune suppression. These results suggest that the immunomodulatory effects of the water-extracted GR, PA, AR, AA and DR may be, in part, associated with the inducing IL-2 and IFNr mRNA gene expression in and regulation of NO production in macrophage cells.

• The Korea Journal of Herbology
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• v.23 no.4
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• pp.91-101
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• 2008

Objectives: In this study, we investigated the inhibitory effects of Ampelopsis Radix methanol(AR-M) extract on allergic inflammation in activated human mast cells and its potential therapeutic or toxic effects. Methods: Ampelopsis Radix(AR) was extracted with 80% methanol. HMC-1 cells, a human mast cell line, were treated with different concentrations of AR-M extract, and then stimulated with PMA plus A23187. The cell toxicity of AR-M extract was determined by MTT assay. The concentrations of $PGE_2$ and cytokines were measured by ELISA. The gene expression of COX-2 and its protein levels were determined by RT-PCR and Western blot. The phosphorylation of ERK MAPK and the NF-${\kappa}B$ activation were determined by Western blot. Results: AR-M extract was significantly inhibited the production of PGE2 and inflammatory cytokines(TNF-${\alpha}$, IL-6 and IL-8) in PMA/A23187-stimulated HMC-1 cells. AR-M extract also attenuated the mRNA expression of COX-2 and its protein induction. Furthermore, AR-M extract attenuated PMA/A23187-induced phophorylation of ERK1/2 MAPK and the NF-${\kappa}B$ p65 subunit translocation into nuclear of HMC-1 cells. AR-M extract significantly decreased PMN A23187-induced release of histamine in a dose-dependent manner. Conclusions: These results indicate that Ampelopsis Radix shows the property of anti-allergic inflammation In vitro through suppressing the production of inflammatory mediators released from mast cells, suggesting have a potential for the treatment of allergic diseases.

• YAKHAK HOEJI
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• v.35 no.3
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• pp.203-215
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• 1991

Using the calorimetric [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT)assay, we evaluated the chemosensitivity of 8 anticancer drugs{vincristine(VCR), vinblastine(VBL), adriamycin(ADR), cisplatin(CPDD), etoposide(VP-16), cytosine arabinoside(ara-C), bleomycin (Bleo) and cyclophosphamide(CYC)} and the cytotoxicity-enhancing effects of ($\pm$)-ar-turmerone and the extracts of the crude drugs {Lithospermum eythrorhizon(LE) and Scutellaria baicalensis (SB)} on the above mentioned anticancer drugs against HL-60 and KG-1 cells among 8 anticancer drugs, VCR, VBL, ADR, and CPDD inhibited the growth of both cell lines by more than 50%, while VP-16, ara-C, Bleo, and CYC were less effective. ($\pm$)-ar-Turmerone had significant inhibitory effects against both cell lines, showing the ID$_{50}$ values of 11.730 $\mu\textrm{g}$/ml and 0.292 $\mu\textrm{g}$/ml for HL-60 and KG-1 cells. respectively. But the extracts of LE and SB roots showed no significant cytotoxic effects. According to ID$_{50}$ values, the cytotoxicities of VCR, VBL and ADR against HL-60 were enhanced two, eight and three times by mixing ($\pm$)-ar-turmerone, five, seven and three times by adding the extract of LE root, and twenty, six and three times by mixing the extract of SB root, respectively. The cytotoxicities of the above mentioned drugs against KG-1 cell were enhanced two, seven and three times by mixing ($\pm$)-ar-turmerone, two, three and three times by combining wilth the extract of LB root, and two, five and two times by adding the extract of SB root, respectively. The cytotoxicity-potentiating effects of ($\pm$)-ar-turmerone and the extracts of LE and SB roots against HL-60 cell were greater than KG-1 cell.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.41-43
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• 1999

Among the feffoelectric thin films that have been widely investigated for ferroelectric random access memory (FRAM) applications, SrBi$_2$Ta$_2$$O_{9}$ thin film is appropriate to memory capacitor materials for its excellent fatigue endurance. However, very few studies on etch properties of SBT thin film have been reported although dry etching is an area that demands a great deal of attention in the very large scale integrations. In this study, the a SrBi$_2$Ta$_2$$O_{9}$ thin films were etched by using magnetically enhanced inductively coupled Ar/CHF$_3$ plasma. Etch properties, such as etch rate, selectivity, and etched profile, were measured according to gas mixing ratio of CHF$_3$(Ar$_{7}$+CHF$_3$) and the other process conditions were fixed at RF power of 600 W, dc bias voltage of 150 V, chamber pressure of 10 mTorr. Maximum etch rate of SBT thin films was 1750 A77in, under CHF$_3$(Ar+CHF$_3$) of 0.1. The selectivities of SBT to Pt and PR were 1.35 and 0.94 respectively. The chemical reaction of etched surface were investigated by X-ray photoelectron spectroscopy (XPS) analysis. The Sr and Ta atoms of SBT film react with fluorine and then Sr-F and Ta-F were removed by the physical sputtering of Ar ion. The surface of etched SBT film with CHF$_3$(Ar+CHF$_3$) of 0.1 was analyzed by secondary ion mass spectrometer (SIMS). Scanning electron microscopy (SEM) was used for examination of etched profile of SBT film under CHF$_3$(Ar+CHF$_3$) of 0.1 was about 85˚.85˚.˚.

• Allergy, Asthma & Immunology Research
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• v.10 no.6
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• pp.662-674
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• 2018

Purpose: Group 2 innate lymphoid cells (ILC2s) have been implicated in the pathogenesis of allergic disease. However, the effect of allergen-specific immunotherapy (AIT) on ILCs remains to be clarified. The aim of this study was to evaluate the levels of ILC subsets in allergic rhinitis (AR) patients in response to house dust mite (HDM)-specific immunotherapy. Methods: We enrolled 37 AR patients undergoing AIT (16 responders and 11 non-responders) for 2 years, 35 HDM AR patients and 28 healthy subjects. Peripheral blood mononuclear cells (PBMCs) were analyzed by flow cytometry to identify ILC subsets. Stimulation of ILC2s with recombinant allergen-specific protein was used to determine ILC2's activation (CD69 expression). Results: Responder AIT patients and healthy subjects had a decreased frequency of circulating ILC2s compared to non-responder AIT and AR patients. Conversely, ILC1s from responder AIT patients and healthy subjects showed increased frequency compared to non-responder AIT and AR patients. The frequency of ILC3s natural cytotoxicity receptor $(NCR)^+$ and $NCR^-$ in responder AIT patients was significantly lower compared to AR patients and healthy subjects. The ILC1: ILC2 proportion in responder AIT patients was similar to that of healthy subjects. PBMCs from patients who were responders to AIT had a significantly lower expression of the activation marker CD69 on ILC2s in response to allergen re-stimulation compared to AR patients, but no difference compared to non-responder AIT patients and healthy subjects. Conclusions: We propose that AIT might affect ILC responses. The activation of ILC2s was reduced in AR patients treated with AIT. Our results indicate that a relative ILC1/ILC2 skewed response is a possible key to successful AIT.