• Journal of the Korean institute of surface engineering
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• v.47 no.1
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• pp.1-6
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• 2014

The copper deposit on steel plate was prepared by pyrophosphate copper plating solution made with variation of inorganic additive. $NH_4OH$ and $NH_4NO_3$ were used as inorganic additives. The copper layer characteristics - tensile strength, crystallite size and crystal orientation - were evaluated by X-ray diffraction and Universal Test Machine. The presence of ammonium nitrate results in reduction of average roughness value from $0.08{\mu}m$ to $0.03{\mu}m$. In pyrophosphate copper plating solution without Inorganic additive, tensile strength of electrodeposit copper foil was reduced from 600 MPa to 180 MPa after 7 days aging. However, when adding ammonium nitrate, there was almost no change of tensile strength, intensity of crystal orientation - (111), (200) and (220) - and crystallite size (2~30 nm).

• Electrical & Electronic Materials
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• v.10 no.1
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• pp.33-38
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• 1997

The green emitting phosphors of the Field Emission Display(FED), Al codoped ZnGa$_{2}$O$_{4}$:Mn, were synthesized and sintered at high temperature. From X-ray diffraction measurements, it was confirmed that poly crystalline ZnGa$_{2}$O$_{4}$ and ZnAI$_{2}$O$_{4}$ solid solution coexist in Al codoped ZnGa$_{2}$O$_{4}$:Mn. Photoluminescence spectra of Al codoped ZnGa$_{2}$O$_{4}$:Mn show that the main peak position is shifted from 504 nm to 513 nm with the increase of Al concentration. The brightness was improved with the amount of Al dopant. It showed the maximum value at the doping level of 0.03 mole and then, it degraded rapidly. These results are due to the superposition of emission from . ZnGa$_{2}$O$_{4}$:Mn and ZnAI$_{2}$O$_{4}$:Mn.

• Korean Journal of Materials Research
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• v.9 no.3
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• pp.301-306
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• 1999

Cu/Cr/polyimide 계에서 금속박막 두께와 폴리이미드 표면의 플라즈마 전처리 조건에 따른 필 테스트 결과로부터 Park와 Yu의 X-선 측정에 의한 방법과 Moidu등의 이론적 방법을 통애 Cr/polyimide 계면균열의 계면파괴에너지를 구했다. 두 방법으로 구한 박막의 소성일과 계면파괴어네지는 대부분의 경우에 대해 서로 잘 일치하였으며, 이와 같은 실험적 방법과 이론적 방법 모두 계면파괴에너지의 측정에 유용함을 알 수 있었다. 계면파괴에너지는 박막 두께에 거의 무관하였으며, 0.03, 0.036 그리고 0.05 W/$\textrm{cm}^2$의 rf플라즈마 밀도에 대해 각각 $46.8\pm$17.8, $170.3\pm$42.9 그리고 $253.9\pm$44.4 J/$\m^2$의 계면파괴에너지를 얻었다.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.1
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• pp.13-22
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• 2015

Purpose : We investigated the safety of Intrabeam$^{TM}$ system, X-ray unit for Intraoperative Radiotheray (IORT) by measuring surface dose using Optically Stimulated Luminescent Dosimeter(OSLD). Materials and Methods : 30 patients were selected, who were in breast cancer patients and had an operation of breast conserving surgery (BCS). At the inner surface of tumor bed, 20 Gy were described, and 5 Gy at 1cm depth from the inner surface. Along the size of tumor bed which could be decided after resection of tumor, the size of applicator were determined. Usual treatment time were from 18 to 40 minutes. For the measurement of surface doses, OSLD were placed at superior(U1,2), inferior(D1,2), lateral(L1,2) and medial(M1,2) directions from the center of applicator. Each direction, two OSLD were placed at 0.5 cm and 1.5 cm from the center. Mean, maximum, and minimum doses were analyzed to be compared. Results : Mean values were U1 $2.23{\pm}0.80Gy$, U2 $1.54{\pm}0.53Gy$, D1 $1.73{\pm}0.63Gy$, D2 $1.25{\pm}0.45Gy$, L1 $1.95{\pm}0.82Gy$, L2 $1.38{\pm}0.42Gy$, M1 $2.03{\pm}0.70Gy$, and M2 $1.51{\pm}0.58Gy$. Maximum values were 4.34 Gy at U1, and Minimum values were 0.45 Gy at M2. 13.3 % of patient (4pts out of 30) were reported that surface dose were over 4 Gy. Conclusion : The fact that skin dose of all patients were less than 5 Gy based on OSLD measurement showed the safety of Intrabeam$^{TM}$ system. In the relatively small breast volume, the tendency that surface dose was increased had been shown, which was analyzed by the data of patients who irradiated over 4Gy at skin surface. Therefore, for appropriate indication for IORT, it is suggested that breast volume as well as the size and position of tumor should be carfully considered.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.4
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• pp.263-273
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• 2010

Occupational exposure to wollastonite can occur during its mining, processing and using. Wollastonite was analyzed for its physicochemical properties by transmission electron microscope and scanning electron microscope equipped with energy dispersive X-ray spectrometer. Wollastonite fibers were 3.3${\mu}m$ in diameter(av.) and were 30.5${\mu}m$ in length(av.). The atomic composition of wollastonite was Si 56.41% and Ca 43.59%. Respiratory toxicity of wollastonite has been studied in term sequential in Sprague-Dawely rats. UICC chrysotile (average diameter 0.03${\mu}m$, average length 2.93${\mu}m$) was applied as the positive control. The effects of 2mg wollastonite on respiratory system and pathological changes were evaluated after 1, 4, 8, 12 weeks instilled into rat lungs. Inflammation response broke out from 1 week after instilled with wollastonite and the pathological examination further showed increased legions of granulomatous inflammation after 4 weeks, but decreased granulomatous inflammation after 8 weeks, whereas chrysotile induced progressive interstitial granulomatous inflammation and fibrosis as a function of time.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.612-618
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• 1999

Physicochemical properties of amaranth starch were compared with those of waxy rice and waxy corn starches. Amaranth starch granules vary from $1.1{\sim}1.9\;{\mu}m$ in diameter and are polygonal in shape. Total amylose contents from waxy rice, waxy corn and amaranth starches were 0.01, 0.03 and 0.07%, respectively. Swelling power of amaranth starch granule was slightly different from waxy rice. The swelling power of amaranth increased at $70^{\circ}C$. X-ray diffraction patterns of amaranth and other waxy cereal starches showed an A-type crystalline structure. Relative crystallinities of their starches were similar. According to pasting properties by Rapid Visco-Analyzer, amaranth starch showed a very high gelatinization temperature $(75.1^{\circ}C)$ and lower viscosity and higher stability than other waxy cereal starches during heating and cooling cycle. Peak onset temperatures (To) of starches from waxy rice, waxy corn and amaranth in DSC thermograms were $58.7{\sim}64.0$, 67.2 and $71.5^{\circ}C$, respectively, and their peak enthalpies were similar. Enthalpy of reheated amaranth starch after 3 day storage at $4^{\circ}C$ was higher than those of waxy corn and rices starchs.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.12
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• pp.1-8
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• 2006

An experimental study was carried out in order to investigate the influence of Reynolds number on the near-wake of an oscillating airfoil. An NACA 0012 airfoil was sinusoidally pitched at the quarter chord point, and is oscillated over a range of instantaneous angles of attack of $\pm$6$^{\circ}$. An X-type hot-wire probe was employed to measure the near-wake of an oscillating airfoil, and the smoke-wire visualization technique was used to examine the flow properties of the boundary layer. The free-stream velocities were 1.98, 2.83 and 4.03 m/s and the corresponding chord Reynolds numbers were 2.3${\times}10^4$, 3.3$\times$104 and 4.8${\times}10^4$, respectively. The frequency of airfoil oscillation was adjusted to fix a reduced frequency of K=0.1. The results show that the properties of the boundary layer and the near-wake can dramatically be distinguished in the range of Reynolds numbers between 2.3${\times}10^4$ and 3.3${\times}10^4$, on the other hand, it is similar in the cases of Re=3.3$\times$104 and 4.8$\times$104. This is caused by that the unsteady separation point is dramatically delayed in case of Re= 2.3${\times}10^4$.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.25.1-28
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• 2000

In this study, $Y_2O_3$ thin films were etched with inductively coupled plasma (ICP). The etch rate of $Y_2O_3$ , and the selectivity of $Y_2O_3$ to YMnO$_3$were investigated by varying $Cl_2$/($Cl_2$+Ar) gas mixing ratio. The maximum etch rate of $Y_2O_3$ , and the selectivity of $Y_2O_3$ to YMnO$_3$ were 302/min, and 2.4 at $Cl_2$/($Cl_2$+Ar) gas mixing ratio of 0.2 repetitively. In x-ray photoelectron spectroscopy (XPS) analysis, $Y_2O_3$ thin film was dominantly etched by Ar ion bombardment, and was assisted by chemical reaction of Cl radical. These results were confirmed by secondary ion mass spectroscopy(SIMS) analysis. YCl, and $YC_3$ existed at 126.03 a.m.u, and 192.3 a.m.u, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.25-28
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• 2000

In this study, $Y_2$O$_3$ thin films were etched with inductively coupled plasma (ICP). The etch rate of $Y_2$O$_3$, and the selectivity of $Y_2$O$_3$ to YMnO$_3$ were investigated by varying Cl$_2$/(Cl$_2$+Ar) gas mixing ratio. The maximum etch rate of $Y_2$O$_3$, and the selectivity Of $Y_2$O$_3$ to YMnO$_3$ were 302/min, and 2.4 at Cl$_2$/(Cl$_2$+Ar) gas mixing ratio of 0.2 repectively. In x-ray photoelectron spectroscopy (XPS) analysis, $Y_2$O$_3$ thin film was dominantly etched by Ar ion bombardment, and was assisted by chemical reaction of Cl radical. These results were confirmed by secondary ion mass spectroscopy(SIMS) analysis. YCI, and YCl$_3$ existed at 126.03 a.m.u, and 192.3 a.m.u, respectively

• Journal of the Korean Society of Radiology
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• v.81 no.5
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• pp.1151-1163
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• 2020

Purpose This study aimed to evaluate changes of subprosthetic pannus on cardiac CT and determine its relationship to echocardiographic findings in patients with mechanical aortic valve replacement (AVR). Materials and Methods Between April 2011 and November 2017, 17 AVR patients (56.8 ± 8.9 years, 12% male) who showed pannus formation on CT and had undergone both follow-up CT and echocardiography were included. The mean interval from AVR to the date of pannus detection was 10.5 ± 7.1 years. In the initial and follow-up CT and echocardiography, the pannus extent and echocardiographic parameters were compared using paired t-tests. The relationship between the opening angle of the prosthetic valve and the pannus extent was evaluated using Pearson correlation analysis. Results The pannus extent was significantly increased on CT (p < 0.05). The peak velocity (3.9 ± 0.8 m/s vs. 4.2 ± 0.8 m/s, p = 0.03) and mean pressure gradient (36.4 ± 15.5 mm Hg vs. 42.1 ± 15.8 mm Hg, p = 0.03) were significantly increased. The mean opening angles of the mechanical aortic leaflets were slightly decreased, but there was no statistical significance (73.1 ± 8.3° vs. 69.4 ± 12.1°, p = 0.12). The opening angle of the prosthetic leaflets was inversely correlated with the pannus extent (r = -0.57, p < 0.001). Conclusion The pannus extent increases over time, increasing transvalvular peak velocity and the pressure gradient. CT can be used to evaluate the pannus extent associated with hemodynamic changes that need to be managed by surgical intervention.