• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.5
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• pp.543-552
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• 2003

The effects of a directionally emitting and reflecting dielectric surface on the wall heat flux and medium temperature distribution are studied. The system is an infinite square duct enclosing an absorbing and emitting medium. The emissivity and reflectivity of opaque and gray wall vary with direction. Combined effect of conductive and radiative heat transfer is analyzed using finite difference and the direct discrete-ordinates method. The parameters under study are conduction to radiation parameter, optical depth, refractive index ratio. The results with directional and diffuse properties deviate each other when the conduction to radiation parameter is less than around 0.01. The wall heat flux differs fur optical thickness less than around 0.1. However, the medium temperature profiles differ for optical thickness greater than around 1. Deviations from diffuse property calculations are larger for hot wall with directional property than cold wall with directional property. As n increases from 1.5, the trend changes are observed fur refractive index ratio about n=6.10

• Korean Journal of Human Ecology
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• v.18 no.3
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• pp.749-756
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• 2009

Keeping abreast with the latest consumer's trends, industries are focusing on sensibility aspects of products to meet consumer's needs. The car(?) seat cover fabrics are more closely related to human senses than anything else. This study attempted to investigate which seat cover fabric can give good feeling to consumers and to analyze their characteristics. Twelve kinds of jacquard fabric used for seat cover were selected. The Kawabata Evaluation System was used to measure the mechanical properties of 12 jacquard fabrics, and tactile sensibility(TS), and preference(P) determined by subjective evaluation of 160 participants were also utilized. The stepwise regression analysis was made to select the most significant mechanical properties, and some models for predicting tactile sensibility and preference was developed. The results are briefly summarized as follows: the most important parameter to choose seat cover fabric is a "hygienic property" and the other parameters are 'materials with color fastness', 'compressive property', 'color', 'antibacterial property', 'easy-care property'. The LogSMD, LogB, LC, EM were selected as significant mechanical properties affecting tactile sensibility. Also, the LC, LogB, LogSMD, LogWC, LogMMD were selected as significant mechanical properties affecting preference.

• Textile Coloration and Finishing
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• v.18 no.6 s.91
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• pp.80-87
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• 2006

Nowadays, interests of ultraviolet(UV) protection increased, since the UV dosage on the earth surface has increased over years. Overdose of UV can cause various skin, eye, and even DNA damages. Therefore, it is need to develop a proper mean to protect human skin and eye from UV radiation. In this study, the UV protective effect of green tea extract dyed fabrics with various fiber types were examined. Green tea has an active moiety called 'catechin' having benzene rings in its structure, which would exert a proper UV protective property. Green tea dyed fabrics showed the increase in UV protection, and silk showed the highest increase in UV protection (from 52.2% to 84.5% in UV-A, from 66.1% to 90% in UV-B). The order of UV-A protection increase is silk, wool, nylon and acrylic, PET, and cotton. The order of UV-B protection increase is silk nylon, wool, acrylic, cotton, and PET. In case of silk and nylon, the UV protection property gradually increased as the concentration of green tea extract increased. As a result, it was proven that green tea extract dyeing can improve UV protection property of dyed fabrics in environment-friendly and biocompatible manners.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.9
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• pp.2470-2480
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• 1996

The energy efficiency and bandwidth efficiency are two important criterion in designing a modulation scheme Especially the constant envelope property must be considered as in the non-linear channel tht exit, for example in the nonlinear amplifiers for satellite repeater. The Q$^{2}$AM(Quadrature Quadrature Amplitude Modulation) is a new modulation scheme which combines the Q$^{2}$PSK(Quadrature Quadrature Phase Shift Keying) scheme which increases the signal space dimension and the QAM scheme which increases the bandwidth efficiency using the multi-level signal. The Q$^{2}$AM scheme has by far superior spectrum efficiency compared with the existing modulation schemes. Applying this scheme in the non-linear communication system increses the bandwidth efficiency but cannot envelop property. In this paper, a new system architecture is suggested which satisfies the large spectrum efficiency and constant envelope property by implementing the linear block coding prior to the Q$^{2}$AM modulation. the system has improved in performance by gaining the constant envelope and the additional coding gain. We able to observe the performance improvement of the suggested system(at BER=10$^{-5}$ ) of 4.4 dB for the 16-QAM and 0.7 dB for the Q$^{2}$PSK under the exact spectrum efficiency.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.1
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• pp.60-66
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• 1996

Bradyrhizobium japonicum with different colony morphology populated in five Yeongnam soils of Korea was examined for intrinsic antibiotic resistance to eight antibiotics, serological property by immunoblot and immunodiffusion, and protein profile differentiation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Colony morphological distribution of one hundred and twenty B. japonicum isolates was 47% for "dry". 41% for "wet", and 12% for "dry/wet" type. The total isolates showed such a strong correlation between the morphology and antibiotic resistance. Colony morphology, which though was dominantly consisted of the same type within a serogroup, wasn't absolutely linked to serological property of B. japonicum. Based on these data, colony morphology was too simple to identify variations with B. japonicum isolates : antibiotic resistance such complicated compared with serological analyses.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.307-310
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• 2001

A parameterized complex-number multiplier (PCMUL) core IP (Intellectual Property), which can be used as an essential arithmetic unit in baseband signal processing of digital communication systems, is described. The bit-width of the multiplier is parameterized in the range of 8-b~24-b and is user-selectable in 2-b step. The PCMUL_GEN, a core generator with GUI, generates VHDL code of a CMUL core for a specified bit-width. The IP is based on redundant binary (RB) arithmetic and a new radix4 Booth encoding/decoding scheme proposed in this paper. It results in a simplified internal structure, as well as high-speed, low-power, and area-efficient implementation. The designed IP was verified using Xilinx FPGA board.

• Korean Journal of Materials Research
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• v.29 no.8
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• pp.477-482
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• 2019

The magnetic properties and electronic structures of the B20 crystal structure MnGe and MnSi were investigated using the density functional theory with local density approximation. The low symmetry of the B20 crystal structure plays a very important role to make electromagnetic characteristics of these materials. The important result of the calculations is that it can be observed the appearance of a pair of gaps in the density of states near the Fermi level in both compounds. These features are results from d-band splitting by the low symmetry of the crystal field from B20 crystal structure. It can be seen that there is half-metallic characteristics from the density of states in both compounds. The calculation shows that the value of magnetic moment of MnGe is 5 times bigger than that of MnSi even though they have same crystal structure. The electronic structures of paramagnetic case have a very narrow indirect gap just above the Fermi level in both compounds. These gaps acquire some significance in establishing the stability of the ferromagnetic states within the local density approximation. Calculation shows that the Mn 3d character dominates the density of states near the Fermi level in both materials.

• Communications of the Korean Mathematical Society
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• v.10 no.2
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• pp.305-315
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• 1995

The class $R_{\gamma-1,p}(A,B,\alpha)$ for $-1 \leq B < A \leq 1,\gamma > (B -1)p+(A_B)(p-\alpha)/1-B$ and $0 \leq \alpha < p$ consisting of p-valently analytic functions in the open unit disc is defined with the help of convolution technique. We study containment property, integral transforms and a sufficient condition for an analytic function to be in $R_{\gamma-1,p}(A,B,\alpha)$.

• Journal of the Korean Magnetics Society
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• v.26 no.3
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• pp.76-80
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• 2016

CoSiB is the amorphous ferromagnetic material and multilayer consisting of CoSiB and Pd has perpendicular magnetic anisotropic property. PMA has strong advantages for STT-MRAM. Moreover, amorphous materials have two advantages more than crystalline materials: no grain boundary and good thermal stability. Therefore, we studied the magnetic properties of multilayers consisting of the $Co_{75}Si_{15}B_{10}$ with PMA. In this study, we investigated the magnetic property of the [CoSiB (3, 4, 5, and 6) ${\AA}$/Pd(11, 13, 15, 17, 19,and $24{\AA})]_5$ multilayers and found the annealing temperature dependence of the magnetic property. The annealing temperature range is from room temperature to $500^{\circ}C$. The coercivity and the saturation magnetization of the CoSiB/Pd multilayer system have a close association with the annealing temperature. Moreover, the coercivity especially shows a sudden increasing at the specific annealing temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.594-597
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• 1999

The new green and red phosphors for PDP application activated by T $b^{3+}$ and E $u^{3+}$ were synthesized, and their photoluminance properties were investigated. It was found that the brightness of $Al_3$Gd $B_4$ $O_{12}$ :T $b^{3+}$ green phosphor under 147nm VUV irradiation was higher than that of commercial Z $n_2$ $SiO_4$:M $n^{2+}$ phosphor. But the emitting intensity of A1$_3$Gd $B_4$ $O^{12}$ :E $u^{3+}$ red phosphor was inferior to the commercial (Y,Gd)B $O_3$:E $u^{3+}$. $Al_3$Gd $B_4$ $O_{12}$ Phosphor had a strong excitation band at 160nm associated with the host absorption, and also the photoluminance excitation intensity of $Al_3$Gd $B_4$ $O_{12}$ :T $b^{3+}$ was higher than that of Z $n_2$ $SiO_4$:M $n^{2+}$, but the intensity of $Al_3$Gd $B_4$ $O_{12}$ :E $u^{3+}$ phosphor was smaller than (Y,Gd)B $O_3$:E $u^{3+}$ phosphor In the VUV range. C $e^{3+}$ co-doping in A1$_3$Gd $B_4$ $O^{12}$ :E $u^{3+}$ and substitution of $Al^{3+}$ by G $a^{3+}$ A1$_3$Gd $B_4$ $O^{12}$ :E $u^{3+}$ phosphor were tried, but they did not improved the optical property .d the optical property .ty .