• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.12
• /
• pp.63-70
• /
• 2013

This paper describes a high PSRR low-dropout(LDO) linear regulator for wide frequency range without output-capacitor. Owing to both of the cascode compensation technique and the current buffer compensation technique in nested Miller compensation loop, the proposed LDO not only maintaines high stability but also achieves high PSRR over wide frequency range with reasonable on-chip capacitances. Since the external capacitor is removed by the proposed compensation techniques, the cost for pad is eliminated. The designed LDO works under the input voltage range from 2.5V to 4.5V and provides up to 10mA load current with the output voltage of 1.8V. The LDO was implemented with 0.18um CMOS technology and the area is 300um X 120 um. The measured power supply rejection ratio(PSRR) is -76dB and -43dB at DC and 1MHz, respectively. The operating current is 25uA.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.38 no.10
• /
• pp.699-705
• /
• 2001

Six types of planar thermal converters from TC 1 to TC 6 were designed and fabricated for the purpose of being used as practical standards to alternating current. The respective voltage responses in air and in a vacuum of TC 6, which has the smallest thermal loss, were about 4.03mV/mW and about 6.38 mV/mW. Thermal time constant of TC 6, which has also the smallest heater thermal inertia, was about 8 ms. The respective variations of AC-DC voltage and current transfer errors from sample to sample, which were measured by FRDC(fast reversed DC) method, were about $\pm$0.41 ~$\pm$0.85 ppm and about $\pm$0.15~$\pm$1.16 ppm in the frequent range of 40 Hz~10 KHz with appling 1 V and 5 mA rms sine waves to the converters. All converters investigated exhibited sufficiently low AC-DC transfer errors to be used as practical standards.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.10
• /
• pp.2963-2968
• /
• 2014

We report synthesis and photovoltaic properties of two new conjugated copolymers, PCPDTQxF and PDTSQxF, with 6,7-difluoro-2,3-dihexylquinoxaline unit prepared by Stille coupling reaction. The advantage of 6,7-difluoro-2,3-dihexylquinoxaline based copolymer are high PCEs due to lower HOMO energy level, long wavelength absorption and high hole mobility. The solid films of PCPDTQxF and PDTSQxF showed absorption bands with maximum peaks at about 623 and 493 nm and the absorption onsets at 711 and 635 nm, corresponding to band gaps of 1.74 and 1.95 eV, respectively. The oxidation onsets of the PCPDTQxF and PDTSQxF polymers were estimated to be 0.68 and 0.95 V, which correspond to HOMO energy levels of -5.48 and -5.75 eV, respectively. The PDTSQxF has lower HOMO energy level as compared to PCPDTQxF to lead higher $V_{OC}$ value. The device comprising PCPDTQxF:PCBM (1:2) dissolved to a concentration of 1 wt % in ODCB showed $V_{OC}$ value of 0.62 V, $J_{SC}$ value of $1.14mA/cm^2$, and FF of 0.35, which yielded PCE of 0.25%.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.20 no.6
• /
• pp.591-600
• /
• 1987

To evaluate the detection rate and the density of Vibrio vulnificus by the sample, sampling area and date, 240 sea water samples and marine invertebrates were collected from coastal area of Korea including Pohang, Chungmu, Yeosu, Kunsan, Sihwa and Pusan from March to October, 1986. Eighty two strains oft of 1087 strains isolated from the submitted samples were identified as V. vulnificus. Forty seven of total 240 samples were positive in V. vulnificus which were constituted by 31 out of 138 sea water samples and 16 out of 102 marine invertebrates. Detection rate of V. vulnificus among the invertebrates was high in the crab, Portunus trituberculatus and the ark shell, Anadara broughtonii samples. The samples collected at Kunsan area showed the highest in detection rate of the bacterium as $67\%$ during the study period and the density of V. vulnificus was high in the sea water which was low in salinity.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.226-226
• /
• 2012

The electronic and electrical properties of nickel oxide (NiO) thin films were investigated by reflection electron energy loss spectroscopy (REELS), x-ray photoelectron spectroscopy (XPS), and Hall Effect measurements. REELS spectra revealed that the band gap of the NiO thin film was increased from 3.50 eV to 4.02 eV after annealing the sample at $800^{\circ}C$. Our XPS spectra showed that the amount of Ni2O3 decreased after annealing. The Hall Effect results showed that the doping type of the sample changed from n type to p type after annealing. The resistivity decreased drastically from $4.6{\times}10^3$ to $3.5{\times}10^{-2}$ ${\Omega}{\cdot}cm$. The mobility of NiO thin films was changed form $3.29{\times}10^3$ to $3.09{\times}10^5cm^2/V{\cdot}s$. Our results showed that the annealing temperature plays a crucial role in increasing the carrier concentration and the mobility which leads to lowering resistivity of NiO thin films.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2002.12a
• /
• pp.174-175
• /
• 2002

A ramp-type tunneling magnetoresistance (TMR) junction having structure NiO(60 nm)/pinned Co(10 nm)MiO(60 nm)/barrier SrTiO$_3$(2-10 nm)/free NiFe(10 nm) with the 15 degree slope was investigated. We obtained nonlinear I(V) characteristics for ramp-type tunneling junctions that have distinctive difference with and without applied magnetic field. In the barrier SrTiO$_3$ thickness of 4 nm, the TMR was about 52% at a bias voltage of 50 mV. (omitted)

• Korean Journal of Food Science and Technology
• /
• v.53 no.3
• /
• pp.304-312
• /
• 2021

The present study aimed to develop new physiologically active ingredients from Angelica gigas. The polysaccharides purified from A. gigas, AGE-2c-I, showed potent anti-complementary activity in a dose-dependent manner. C₃ activation products were identified through crossed immuno-electrophoresis using anti-human C₃ antibodies and the anti-complementary activity of AGE-2c-I under Ca⁺⁺-free conditions suggests that AGE-2c-I may induce complementary activation via both alternative and classical pathways. In addition, AGE-2c-I augmented the production of various cytokines, such as interleukin (IL)-6, IL-10, IL-12, and tumor necrosis factor-α, by peritoneal macrophages. Furthermore, intravenous (i.v.) administration of AGE-2c-I dose-dependently enhanced natural killer cell cytotoxicity against YAC-1 lymphoma. In experimental lung metastasis, prophylactic i.v. administration of AGE-2c-I inhibited lung metastasis by 58% at 100 ㎍/mouse. From the above results, we suggest that AGE-2c-I purified from A. gigas has potent immune system-stimulating activities, and is a potentially promising food ingredient beneficial to human health.

• Journal of the Society of Naval Architects of Korea
• /
• v.60 no.1
• /
• pp.1-9
• /
• 2023

In order to improve the propeller cavitation performance composed of Cavitation Inception Speed (CIS), cavitation extent and pressure fluctuation, it needs to improve the wake distribution that flows into the propeller. The warship propeller cavitation is strongly influenced by the wake created at the V-strut of various appendages. The inflow characteristics of the V-strut were investigated using Computational Fluid Dynamics (CFD) and the twisted angles of the V-strut were aligned with upstream flow. The resistance and self-propulsion tests for the model ship with the existing and modified V-struts were conducted in Towing Tank (TT), and wake distribution, CIS, cavitation observation and pressure fluctuation tests were conducted in Large Cavitation Tunnel (LCT). The propeller behind the modified V-strut showed better cavitation characteristics than that behind the existing V-strut. Another model test was conducted to investigate rudder cavitation performance by the change of the V-strut. The rudder cavitation characteristics were not improved by the change of the operating conditions. On the basis of the present study, it is thought that the stern appendages for better propeller cavitation performance would be developed.

• Food Science and Preservation
• /
• v.17 no.4
• /
• pp.563-570
• /
• 2010

We sought to ferment wine from mulberry (Morus alba) juice. The soluble solid content was $9.5{\sim}14.5^{\circ}brix$ on day 6 of fermentation, and gradually fell later; sugar was not further consumed when $3^{\circ}brix$ was attained. Alcohol content rose dramatically on day 6 of fermentation, being 4.5% (v/v) at fermentation temperatures of 16C and 18C, 6.5% (v/v) at 20C, and 8.0% (v/v) at 25C, rising further to 10.5~11.5% (v/v) on day 48, at higher culture temperatures. Citric acid, malic acid, and oxalic acid were present in mulberries. The levels of both citric and oxalic acid fell after fermentation, whereas malic acid concentration increased. All of fructose, glucose, maltose, and sucrose were fermented. Electron-donating ability (EDA) was elevated to over 90% of the control value in mulberry juice diluted to 40% (v/v). SOD-like activities in juice and wine were 80.1% and 72.1% of the control value. Nitrite-scavenging abilities (NSAs) were 86.2% and 85.2% of control in undiluted juice and wine, respectively. Mulberry juice had an activation level higher than that of mulberry wine, but functionality neither rose nor fell after fermentation. Insensory evaluation, the overall wine score was better than average, at 5.00, demonstrating the commercial potential of mulberry wine.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.3
• /
• pp.222-227
• /
• 2006

RAINBOW(Reduced And Internally Biased Oxide Wafers) are a new class of high-displacement, piezoelectric actuator produced by selectively removing oxygen from one surface of ceramic using a high-temperature chemical reduction process. In this paper, RAINBOW actuator materials of $0.4Pb(Ni_{1/3}Nb_{2/3})O_3-0.6Pb(Zr_{x}Ti_{1-x})O_3$ ceramics were prepared. Its dielectric and piezoelectric properties were investigated in the vicinity of MPB. The piezoelectric properties showed the maximum value of ${\epsilon}r$ = 4871, $d_{33}$ = 610 ($10^{-12}$ m/V), $d_{31}$ = -299 ($10^{-12}$ m/V), $k_{33}$ = $71\%$, Qm = 70, in $0.4Pb(Ni_{1/3}Nb_{2/3})O_{3}-0.6Pb(Zr_{405}Ti_{595})O_3$ composition sintered at $1250^{\circ}C$. The strain - electric field characteristics of RAINBOW actuator were significantly improved comparison with the conventional bulk actuator. The prepared RAINBOW actuator showed about $390\;{\mu}m/100\;V$ displacement.