• Proceedings of the Korean Society Of Semiconductor Equipment Technology
• /
• 2007.06a
• /
• pp.179-182
• /
• 2007

Polycrystaline (poly) 3C-SiC thin film on n-type and p-type Si were deposited by APCVD using HMDS, $H_2$, and Ar gas at $1180^{\circ}C$ for 3 hour. And then the schottky diode with Au/poly 3C-Sic/Si(n-type) structure was fabricated. Its threshold voltage ($V_d$), breakdown voltage, thickness of depletion layer, and doping concentration ($N_D$) value were measured as 0.84 V, over 140 V, 61nm, and $2.7{\times}10^{19}\;cm^3$, respectively. The p-n junction diode fabricated by poly 3C-SiC was obtained like characteristics of single 3C-SiC p-n junction diode. Therefore, its poly 3C-SiC thin films are suitable MEMS applications in conjuction with Si fabrication technology.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.22 no.7
• /
• pp.816-825
• /
• 1998

This study surveys the thermal property and air permeability to the weight reduction rate of PET fabrics. For this purpose, 12 kinds of satin and 18 kinds of plain weave fabrics are prepared with change of the physical properties such as weft yarn count, t.p.m. and density. The weight reduction rate was 0%, 12%, 25% and 30%. The warm/cool feeling(Qmax), thermal insulating value(T.I.V.) and thermal conductivity(K) were measured by KES-F7 System and discussed in relation with the weight reduction rate, weft yarn linear density, t.p.m., weft density of fabric and weave structure.

• Applied Chemistry for Engineering
• /
• v.30 no.4
• /
• pp.472-478
• /
• 2019

A stable desalination method of the hardness substance such as $Ca^{2+}$ by controlling the total charge (TC) supplied to the membrane capacitive deionization (MCDI) cell was studied. The adsorption (1.5 V) and desorption (0.0 V) were repeated 30 times while varying the TC in the adsorption process. The concentration and pH of effluent, adsorption and desorption amounts, current densities and cell potentials were analyzed in the desalination process. The maximum allowable charge (MAC) of the carbon electrode used in MCDI cell was measured to be 46 C/g. As a result of operation at TC (40 C/g) below the MAC value, electrode reactions did not occur, resulted in the stable desalination characteristics for a long-term operation. When operating at TCs (50, 60 C/g) above the MAC value, however, the concentration and pH of effluent varied greatly. Also, the scale was formed on the electrode surface due to electrode reactions, and the electric resistance of the cell gradually increased. It was thus concluded that it is possible to remove stably the hardness substance without any electrode reactions by controlling the charge supplied to MCDI cell during the adsorption process.

• Bulletin of the Korean Mathematical Society
• /
• v.50 no.1
• /
• pp.37-56
• /
• 2013

This paper deals with the behavior of positive solutions to the following nonlocal polytropic filtration system $$\{u_t=(\mid(u^{m_1})_x{\mid}^{{p_1}^{-1}}(u^{m_1})_x)_x+u^{l_{11}}{{\int_0}^a}v^{l_{12}}({\xi},t)d{\xi},\;(x,t)\;in\;[0,a]{\times}(0,T),\\{v_t=(\mid(v^{m_2})_x{\mid}^{{p_2}^{-1}}(v^{m_2})_x)_x+v^{l_{22}}{{\int_0}^a}u^{l_{21}}({\xi},t)d{\xi},\;(x,t)\;in\;[0,a]{\times}(0,T)}$$ with nonlinear boundary conditions $u_x{\mid}{_{x=0}}=0$, $u_x{\mid}{_{x=a}}=u^{q_{11}}u^{q_{12}}{\mid}{_{x=a}}$, $v_x{\mid}{_{x=0}}=0$, $v_x|{_{x=a}}=u^{q21}v^{q22}|{_{x=a}}$ and the initial data ($u_0$, $v_0$), where $m_1$, $m_2{\geq}1$, $p_1$, $p_2$ > 1, $l_{11}$, $l_{12}$, $l_{21}$, $l_{22}$, $q_{11}$, $q_{12}$, $q_{21}$, $q_{22}$ > 0. Under appropriate hypotheses, the authors establish local theory of the solutions by a regularization method and prove that the solution either exists globally or blows up in finite time by using a comparison principle.

• Annals of Clinical Neurophysiology
• /
• v.19 no.1
• /
• pp.28-33
• /
• 2017

Background: Previous studies of radial nerve conduction study (NCS) did not present how to measure the length of the radial nerve across the elbow, and did not even mention how to manage the spiral course of the nerve. This study aimed to applicate the most reliable method to measure the length of the radial nerve during NCS. Methods: Three points (A, B, and C) were determined along the relatively straight course of the radial nerve. The distance was measured using three different methods: L1) straight distance corresponding to the A-C distance, L2) sum of the distances corresponding to the A-B-C distance, L3) based on the L2, but the elbow is flexed at a $45^{\circ}$ angle. We compared the three methods of distance measurement and the calculated nerve conduction velocities (V1, V2, and V3) in normal healthy subjects. Results: 19 normal participants were enrolled. The mean value for method L1, L2 and L3 were $22.5{\pm}1.8cm$, $24.0{\pm}2.1cm$, and $23.2{\pm}2.1cm$ (p < 0.001). Calculated conduction velocities using those distance measurement methods as follows (p < 0.001): V1 ($60.9{\pm}2.7m/s$), V2 ($64.6{\pm}3.3m/s$), and V3 ($63.4{\pm}3.9m/s$). V2 was significantly greater than V1 and V3 (p < 0.001, p = 0.010, respectively). Conclusions: The distance measurement using a stopover point near the lateral epicondyle between two stimulus points in position of a fully extended elbow with forearm pronation is the most appropriate posture for radial motor NCS.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.59 no.3
• /
• pp.253-257
• /
• 2010

The frequency is an important operation parameter for the control, protection, and stability of a power system. The frequency as a key index of power quality can be indicative of system abnormal conditions and disturbances. Due to the sudden change in generation and loads or faults in power system, the frequency is supposed to deviate from its nominal value. It is essential that the frequency must be maintained very close to its nominal frequency. An accurate monitoring of the power frequency is essential to optimal operation and prevention for wide area blackout. As most conventional frequency estimation schemes are based on DFT filter, it has been pointed out that the gain error could cause defects when the frequency is deviated from nominal value. This paper presents an advanced frequency estimation technique using gain compensation to improve the performance of DFT filter based techniques. To evaluate performance of the proposed algorithm, the 765kV T/L system in Korea is simulated by EMTP-RV software. The proposed technique can reduce the gain error caused when the power system frequency deviates from nominal value.

• Journal of the Korean Vacuum Society
• /
• v.12 no.1
• /
• pp.16-19
• /
• 2003

Ni thin films on the p-InP (In) substrates were grown at room temperature by using the ion beam-assisted deposition. In order to determine the work function of the Ni thin films, the $\gamma$values were measured as functions of the acceleration voltages by using Ne, Ar, $N_2$. and Xe ion sources. The dependences of the values on various gases and on the acceleration voltages of the focused ion beam were obtained to determine the work function of the Ni thin films. The value of the work function of the Ni thin films grown on the p-InP (100) substrate was 5.8 eV ~ 5.85 eV. These results provide important information on the electronic properties of Ni thin films grown on p-InP (100) substrates at room temperature.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.12 no.3
• /
• pp.135-146
• /
• 2008

In this study, the effect of epoxy mortar panel as the shear strengthening material of reinforced concrete beam is investigated by loading test. The main variables are the kind of strengthening material, the amount of reinforcement and the spacing of CFS(Carbon Fiber Sheet) stirrups. The design method to use epoxy mortar panel as shear strengthening of reinforced concrete beam took the shear capacity as the form of the sum of $V_c$, $V_s$, $V_{sheet}$ and $V_p$. By making a comparison between the values calculated by the proposed shear strength prediction formula and those from the loading test results, the mean value was 1.10 and the standard deviation was 8.16%.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.11
• /
• pp.3399-3404
• /
• 2013

A new accepter unit, pyrrolo[3,2-b]pyrrole-2,5-dione, was prepared and utilized for the synthesis of the conjugated polymers containing electron donor-acceptor pair for OPVs. Pyrrolo[3,2-b]pyrrole-2,5-dione unit, regioisomer of the known pyrrolo[3,4-c]pyrrole-1,4-dione, is originated from the structure of stable synthetic pigment. The new conjugated polymers with 1,4-diphenylpyrrolo[3,2-b]pyrrole-2,5-dione, thiophene and carbazole were synthesized using Suzuki polymerization to generate P1 and P2. The solid films of P1 and P2 show absorption bands with maximum peaks at about 377, 554 and 374, 542 nm and the absorption onsets at 670 and 674 nm, corresponding to band gaps of 1.85 and 1.84 eV, respectively. To improve the hole mobility of the polymer with 1,4-bis(4-butylphenyl)-pyrrolo[3,2-b]-pyrrole-2,5-dione unit, which was previously reported by us, the butyl group at the 4-positions of the N-substituted phenyl group was substituted with hydrogen and methyl group. The field-effect hole mobility of P2 is $9.6{\times}10^{-5}cm^2/Vs$. The device with $P2:PC_{71}BM$ (1:2) showed $V_{OC}$ value of 0.84 V, $J_{SC}$ value of 5.10 $mA/cm^2$, and FF of 0.33, giving PCE of 1.42%.

• Korean Journal of Poultry Science
• /
• v.21 no.3
• /
• pp.157-168
• /
• 1994

This study was carried out to elucidate the time course variation of vitamin $D_{3}$ (V$D_{3}$) and 25-hydroxyvitamin $D_{3}$ [25(OH)$D_{3}$] contents in the liver and skeleton of 3-wk old broiler chicks when treated with different UV irradiation procedure. Day-old Hubbard chicks were fed vitamin D deficient diet for 3 wk and exposed to medium wave ultraviolet(UVB) light with different irradiation procedures. Procedure I was 30 min continuous irradiation(O.204 mJ /$cm^{2}$) and Procedure II was three seperate 10 min irradiation with 12 h intervals, and Procedure III was three seperate 10 min irradiation with 24 h intervals. The liver and skeleton samples were collected at 10 different times between 0000~2400 h after the last irradiation. The V$D_{3}$ and 25(OH)$D_{3}$ fractions wereseparated by Sep-Pak silica cartridge and the concentrations were determined by normal phase HPLC. The mean content of V$D_{3}$ in the liver of the birds treated by Procedure II was 6.68 ng /g, which was higher than 5.60 and 5.30 ng /g from Procedure I and Ill, respectively(P<.O5). With regard to the effect of elapsed time after UVB irradiation on the V$D_{3}$ concentration of the liver, 96 h treatment showed the highest value(13.08 ng/g)(P<.05). There was a significant(P$D_{3}$ were significantly(P$D_{3}$ in the skeleton of tibia and femur, there were no significant differences among Procedure I, II and III, but significant differences were found among those from various elapsed time after irradiation, The highest value was shown at 96 h(O.99 ng /g) treatment, and interaction between irradiation procedure and elapsed time was not significant. With regard to the mean content of 25(OH)$D_{3}$ in bone, the Procedure II(18.79 ng /g) and III(17.73 ng /g) showed higher values than Procedure I did (P<.05), and the 12 h elapsed time showed the highest value(31.17 ng /g) among 10 treatments (P<.05), however, there was no significant interaction between exposing procedure and elapsed time. In conclusion, the Procedure II would he more desirable than Procedure I or III to produce more V$D_{3}$ and 25(OH)$D_{3}$ in the liver and skeleton of birds by exposing to the UVB light. Also, it was verified that 25(OH)$D_{3}$ increases more quickly than V$D_{3}$ in both tissues tested and is utilized more quickly to recover from the rickets of chicks.