• Journal of the Korean Society of Radiology
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• v.16 no.1
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• pp.15-23
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• 2022

3D printing technology is being used in various fields such as medicine and biotechnology, and materials containing metal powder are being commercialized through recent material development. Therefore, this study intends to analyze the photon spectrum during added filtration using 3D printing material during diagnostic X-ray examination through simulation. Among the Monte Carlo techniques, MCNPX (ver. 2.5.0) was used. First, the appropriateness of the photon spectrum generated in the simulation was evaluated through SRS-78 and SpekCalc, which are X-ray spectrum generation programs in the diagnostic field. Second, photon spectrum the same thickness of Al and Cu filters were obtained for characterization of 3D printing materials containing metal powder. In addition, the total photon fluence and average energy according to changes in tube voltage were compared and analyzed. As a result, it was analyzed that PLA-Al required about 1.2 ~ 1.4 times the thickness of the existing Al filter, and PLA-Cu required about 1.4 ~ 1.7 times the thickness of the Cu filter to show the same degree of filtration. Based on this study in the future, it is judged that it can be utilized as basic data for manufacturing 3D printing additional filters in medical fields.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.503-508
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• 2017

Screen X is one of the Premium Large-Format platforms. Screen X projects images and video along the side wall of the theatre that go in synch with the front main screen. It's a different way of immersing the audience. This technique demands film-makers taking the two new "screens" into account when making movies. Screen X is the most obvious feature of viewing content with a range of 270 degrees. Viewers can view the experience of viewing experiences beyond the frame of screen screens by allowing viewers to experience the experience beyond the frame of screen screens, which means screen X can immerse the audiences without 3D glasses. Based on the results of this study, studies of content specifications and how they fit in the screen X are studied, and goals for maximizing the visual effects of the visual effects are studied. Looking forward to future research paper researchers and industry professionals who will benefit from future research papers.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.5
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• pp.481-488
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• 2013

Nitric oxide ($NO_x$) formation characteristics in non-premixed diffusion flames of methane fuels have been investigated experimentally and numerically by adding 10% ammonia to the fuel stream, according to the variation of the oxygen ratio in the oxidizer with oxygen/carbon dioxide and oxygen/nitrogen mixtures. In an experiment of coflow jet flames, in the case of an oxidizer with oxygen/carbon dioxide, the $NO_x$ emission increased slightly as the oxygen ratio increased. On the other hand, in case of an oxygen/nitrogen oxidizer, the $NO_x$ emission was the maximum at an oxygen ratio of 0.7, and it exhibited non-monotonic behavior according to the oxygen ratio. Consequently, the $NO_x$ emission in the condition of oxyfuel combustion was overestimated as compared to that in the condition of conventional air combustion. To elucidate the characteristics of $NO_x$ formation for various oxidizer compositions, 1D and 2D numerical simulations have been conducted by adopting one kinetic mechanism. The result of 2D simulation for an oxidizer with oxygen/nitrogen well predicted the trend of experimentally measured $NO_x$ emissions.

• Journal of the Korean Ceramic Society
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• v.42 no.7 s.278
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• pp.475-482
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• 2005

Zn$_{l-x}$Co$_{x}$O (x = 0.05 - 0.20) films were grown on Coming 7059 glass by sol-gel process. A homogeneous and stable Zn$_{l-x}$Co$_{x}$O sol was prepared by dissolving zinc acetate dihydrate (Zn(CH$_{3}$COO)$_{2}$$\cdot$2H$_{2}$O), cobalt acetate tetrahydrate ((CH$_{3}$)$_{2}$$\cdot$CHOH) and aluminium chloride hexahydrate (AlCl$_{3}$ $\cdot$ 6H$_{2}$O) as solute in solution of isopropanol ((CH$_{3}$)$_{2}$$\cdot$CHOH) and monoethanolamine (MEA:H$_{2}$NCH$_{2}$CH$_{2}$OH). The films grown by spin coating method were postheated in air at 650°C for 1 h and annealed in the condition of vacuum (5 $\times$ 10$^{-6}$ Torr) at 300$^{\circ}C$ for 30 min and investigated the nature of c-axis preferred orientation and physical properties with different Co concentrations. Znl_xCOxO thin films with different Co concentrations were well oriented along the c-axis, but especially a highly c-axis oriented Zn$_{l-x}$Co$_{x}$O thin film was grown at 10 at$\%$ Co concentration. The transmittance spectra showed that Zn$_{l-x}$Co$_{x}$O thin films occur typical d-d transitions and sp-d exchange interaction became activated with increasing Co concentration. The electrical resistivity of the films at 10 at$\%$ Co had the lowest value due to the highest c-axis orientation. X-ray photoelectron spectroscopy and alternating gradient magnetometer analyses indicated that no Co metal cluster was formed, and the ferromagnetic properties appeared, respectively. The characteristics of the electrical resistivity and room temperature ferromagnetism of Zn$_{l-x}$Co$_{x}$O thin films suggested the possibility for the application to dilute magnetic semiconductors.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.2
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• pp.220-228
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• 1996

CdTe single crystals were grown by vertical Bridgman method using double furnace with two siliconit heating elements. When the peak temperature of the upper furnace was fixed at $1150^{\circ}C$ and that of the lower furnace was $800^{\circ}C$, the temperature gradient was about $22.5^{\circ}C$/cm. The lattice constant $a_0$ was $6.482\AA$ from the X-ray diffraction and the band gap energy obtained from the optical absorption experiment at room temperature was 1.478 eV. PL spectrum showed that the bound exciton emission peak was resolved into ($A^0,X$) (1.5902, 1.5887 eV), ($h\;D^0$) (1.5918 eV) and ($D^0,X$ (1.5928, 1.5932 eV), and we have also calculated binding energy and ionization energy of the neutral donor and acceptor.

• Journal of the Korean Chemical Society
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• v.25 no.3
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• pp.183-189
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• 1981

Iron and titanium, the major constituents in iron ores, were X-ray spectrometrically determined by using the dilution parameter method. A standard and samples possessing a similar composition were diluted with the diluent $ZrO_2$ to their proper respective ratios. After measuring the intensity of the fluorescent X-ray, the dilution parameter was calculated from the following equation. $Pa=\frac{\frac{I_{as}}{(I_{as})_d}}{D-1}{^{-1}}$The dilution parameters were used to correct the difference between the matrix effect of the standard and that of the sample. The content of the major constituents was calculated, without using any standard calibration curves, from the following equation;$W_a=W_a^*{\cdot}{\frac{I_as}{I_{as}^*}{\cdot}\frac{P_a^*}{P_a}$where asterisks indicate the standard. The results agreed with those of the wet analysis within 2% of relative error, and the precision of the experiment was also tolerably good.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.2
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• pp.90-94
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• 2016

In this work, [$Pb(Mg_{1/2}W_{1/2})_{0.03}(Ni_{1/3}Nb_{2/3})_x(Zr_{0.5}Ti_{0.5})_{0.97-x}O_3-BiFeO_3$] (x=0.02 to 0.12) composition ceramics were fabricated by the conventional soild state reaction method and their microstructure and piezoelectric properties were investigated according to PNN substitution. The addition of small amount of $BiFeO_3$, $Li_2CO_3$, and $CaCO_3$ were used in order to decrease the sintering temperature of the ceramics. The XRD (x-ray diffraction patterns) of all ceramics exhibited a perovskite structure. The sinterability of PMW-PNN-PZT-BF ceramics was remarkably improved using liquid phase sintering of $CaCO_3$, $Li_2CO_3$. However, it was identified from of the X-ray diffraction patterns that the secondary phase formed in grain boundaries decreased the piezoelectric properties. According to the substitution of PNN, the crystal structure of ceramics is transformed gradually from a tetragonal to rhombohedral phase. The x=0.10 mol PNN-substituted PMW-PNN-PZT-BF ceramics sintered at $920^{\circ}C$ showed the optimum values of piezoelectric constant($d_{33}$), piezoelectric figure of merit($d_{33{\cdot}}g_{33}$), planar piezoelectric coupling coefficient($k_p$) and density : $d_{33}=566$ [pC/N], $g_{33}=29.28[10^{-3}mV/N]$, $d_{33{\cdot}}g_{33}=16.57[pm^2/N]$, $k_p=0.61$, density=7.82 [$g/cm^3$], suitable for duplex ultrasonic sensor application.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.190-191
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• 2006

We have investigated optical properties of Si/graded-$Si_{1-x}Ge_x$/Si heterostructures grown by reduced pressure chemical vapor deposition. Compared to standard condition using Si(100) substrate and growth temperature of $650^{\circ}C$, Si(111) resulted in low growth rate and high Ge mole fraction. Also samples grown at higher temperatures exhibited increased growth rate and reduced Ge mole fraction. The features regarding both substrate temperature and crystal orientation, representing high incorporation of silicon supplied from gas stream played as a key parameter, illustrate that reaction control were prevailed in this process growth condition. Using secondary ion mass spectroscopy and spectroscopic ellipsometry, microscopic changes in atomic components could be analyzed for Si/graded-$Si_{1-x}Ge_x$/Si heterostructures.

• Journal of Advanced Navigation Technology
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• v.28 no.2
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• pp.193-200
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• 2024

This paper describes the design and development of a transmit receiver module(TRM) for mounting on X-band SAR of the NEXTSat-2. The TRM generates the chirp signal with required bandwidth through the DDS in X-band and performs frequency conversion, combination for the signal to transmit and be received and frequency synthesis. Tx path of the TRM produces signals of total 28 bandwidths up to 96.8 MHz and has output signal level of more than + 9.37 dBm. Rx path of the TRM has minimum noise figure of 15.7 dB. The measurement results show that required requirements are satisfied. The TRM is installed on the NEXTSat-2 flight model(FM), launched by KSLV-II(Nuri) on May 23, 2023 and currently operational.

• Journal of Animal Environmental Science
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• v.13 no.1
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• pp.21-28
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• 2007

This experiment was conducted to determine the effect of feed intake and water consumption on milk yield and manure production in milking cows. The average feed intake(dry matter) of milking cows were 19.5kg/hd/d. Spring(23.9kg) and fall(22.1kg) feed intake rates when higher than in the summer(17.0kg) and winter(15.3kg/hd/d). The average water consumption of milking cows were $77.2\ell/hd/d$. Summer showed the highest value$(85.5\ell/hd/d)$ and winter showed the lowest value$(62.2\ell/hd/d)$. The average milk yield during spring, summer, fall, and winter was 30.8, 24.0, 25.4, and 23.7kg/hd/d, respectively. Milk yield during spring was found to be statiscally greater than for the other seasons. Manure production of milking cows during spring, summer, fall, and winter was 64.4, 63.5, 60.4, and 51.0kg/hd/d, respectively. Consequently, a relatively high correlation between milk yield and water consumption$(R^2=0.7742)$, milk yield and feed intake$(R^2=0.7459)$, water, consumption and urine production$(R^2=0.7422)$, feed intake and feces production$(R^2=0.6044)$, and milk yield and feces production$(R^2=0.6920)$ were observed in milking cows. The other hand, correlation between water consumption and feces production$(R^2=0.2950)$, feed intake and urine production $(R^2=0.1985)$, and milk yield and urine production$(R^2=0.2335)$ were found to be relatively low. Therefore, correlation equation between milk yield and feed intake, milk yield and water consumption can be estimated from : $Y=0.1919X_1+11.181(R^2=0.7742),\;Y=0.8568X_2+9.3067(R^2=0.7459)$(Y=milk yield $X_1=water$ consumption, $X_2=feed$ intake).