• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1745-1750
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• 2013

A novel green aqueous mobile phase modified with room temperature ionic liquids (RTILs) was employed in the absence of volatile organic solvents or ion-pairing reagents to analyze thiamine, a very polar compound, by reverse phase high performance liquid chromatography (RP-HPLC). Due to its strongly hydrophilic nature, thiamine was eluted near the column dead time ($t_0$) using a mobile phase without adding RTILs or ion-pairing reagents, even if a 100% aqueous mobile phase, which has weak elution power under reverse phase conditions, was used. Thus, 1-ethyl-3-methyl-imidazolium hexafluorophosphate ([EMIM][$PF_6$]), which has the strongest chaotropic effect, was selected as a mobile phase additive to improve retention and avoid baseline disturbances at $t_0$. Various mobile phase parameters such as cation moiety, chaotropic anion moiety, pH and concentration of RTILs were optimized to determine thiamine at the proper retention time. Method validation was performed to assess linearity, intra- and inter-day accuracy and precision, recovery and repeatability; all results were found to be satisfactory. The developed method was also compared to the current official United States Pharmacopoeia (USP) and Korean Pharmacopoeia (KP) methods using an organic mobile phase containing an ionpairing reagent by means of evaluating various chromatographic parameters such as the capacity factor, theoretical plate number, peak asymmetry and tailing factor. The results indicated that the proposed method exhibited better efficiency of thiamine analysis than the official methods, and it was successfully applied to quantify thiamine in pharmaceutical preparations.

• Journal of Veterinary Clinics
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• v.20 no.3
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• pp.312-316
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• 2003

This study was performed to investigate the reverse effects of Jen Chung(Ren Thong, Shui Gou, GV-26) electroacupuncture after tiletamime-zolazepam administration in dogs. Seven healthy dogs ranging in weigh from 3.5 to 6.5 kg were used in this experiment. The treatment group was electrostimulated to Jen Chung(+) and Su Liao(Shan Gen, GV-25, -) for 20 minutes after 10 minutes of anesthesia. The control group I was anesthetized with tiletamine-zolazepam. The control group II was electrostimulated to nonacupuncture point for 20 minutes after 10 minutes of anesthesia. Various parameters were evaluated including the onset and recovery time of anesthesia, heart rates, body temperature, respiratory rates and electrocardiogram. The recovery time of the treatment group was shorter than that of the control group I and the control group II(p < 0.05). The treatment group had an increase in the heart rate from 20 minutes to 30 minutes after administration of tiletamime-zolazepam compared to the control group I and control group II(p < 0.05). The decrease in the body temperature was observed in all groups, but the body temperature of the treatment group was higher than the body temperature of the other groups. Respiratory rates gradually increased in all groups, but the treatment group had an increase in the respiratory rates from 20 minutes to 30 minutes after administration of tiletamime-zolazepam compared to the other groups. In the three groups, there was no specific finding on the electrocardiogram. In the result, the electroacupuncture on Jen Chung in dogs was effective for the reversed effects the tiletamine-zolazepam anesthesia 20 minutes after induction.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.221-221
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• 2006

The SMD type P-N junction diode with ceramic package for diode case were fabricated. It was made this diode with simple process from $Al_2O_3$ ceramic chip, solder preform, diode chip, coating reagent and conductive paste for chip terrmination. Its merit is small size, easy manufacture. fast cooling with ceramic case. The electric characteristics of the diode such as reverse recovery time, breakdown voltage, forward voltage, and leakage current were 5 28ns, 1322V, 1.08V, $0.45{\mu}A$.

• Journal of KIISE:Information Networking
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• v.29 no.1
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• pp.77-85
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• 2002

The surge in use of networks has recently increased demands for cryptography. Cryptography, however, can cause various problems because of difficulty of key management. A lot of researchers have been concentrating on the key recovery technique to eliminate the reverse effect of using these kinds of security and to promote positive aspects of using it. They have suggested many key recovery techniques up to the present. we propose a mechanism as a solution, which are employed to reduce the time needed to reconnect SG and the host in Host-to-Gateway in VPNs supporting IPsec, in case they are disconnected. This new mechanism using KRFSH stores information at each session in advance so that users can recall the session information when needed to rebuild the tunnel between SG and the host in a VPN. As a result, the mechanism built into SG will solve the problems above in host-to-gateway VPNs using IPsec.

• Journal of Convergence Society for SMB
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• v.3 no.2
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• pp.9-17
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• 2013

Android applications market has increased rapidly due to the popularity of smart phones. In order to high competitiveness in the application market should be high productivity, reduce cost. And short development cycle is required because of increased the android applications demand. Owing to develop applications in short time, the requirements analysis, design process are able to omitted. But in the case of reuse application at development phase, involved many problems because omit document or design. so target of this paper is android application source code that omit document or design. we propose architecture recovery techniques from android application source code by reverse engineering with identify functions are reused. We expect that increase productivity and reduce development cost, smooth maintain by proposed technique.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.67-68
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• 2008

In this study we have developed a packaged silicon carbide power diode with blocking voltage of 2kV. PiN diodes with 7 field limiting rings (FLRs) as an edge termination were fabricated on a 4H-SiC wafer with $30{\mu}m$-thick n-epilayer with donor concentration of $1.6\times10^{15}cm^{-3}$. From packaged PiN diode testing, we obtained reverse blocking voltage of 2kV, forward voltage drop of 4.35V at 100A/$cm^2$, on-resistance of $6.6m{\Omega}cm^2$, and about 8 nanosec reverse recovery time. These properties give a potential for the power system application.

• The KIPS Transactions:PartC
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• v.8C no.6
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• pp.775-782
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• 2001

Recently the use of Linux OS is increasing to tremendous figures. But due to the fact that Linux is distributed on an open-source policy, the need of security is an upcoming question which leads to widespread development of security on a Linux based environment. Cryptography, however, can cause various problems because of difficulty of key management. A lot of researchers have been concentrating on the key recovery technique to eliminate the reverse effect of using these kinds of security and to promote positive aspects of using it. In this thesis I am suggesting an mechanism based on the key recovery technique, as a method to save time in recovery and resetting a disconnection between two end-users through IPSec (IP Security) protocols in a VPN (Virtual Private Network) environment. The main idea of the newly suggested mechanism, KRFSH (Key Recovery Field Storage Header), is to store the information of the session in advance for the case of losing the session information essential to establish a tunnel connection between a SG and a host in the VPN environment, and so if necessary to use the pre-stored information for recovery. This mechanism is loaded on the IPSec based FreeS/WAN program (Linux environment), and so the VPN problem mentioned above is resolved.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.516-520
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• 1991

This paper presents a comparative analysis of two inverter power supply topologies for induction heating and melting applications. The comparison is based on criteria such as resonant condition, component ratings, minimum and maximum operating frequencies, operation under varying load conditions, inverter starting current, and diode reverse recovery time. The voltage source series/parallel resonant inverters are found to offer the best overall performance with respect to converter utilization.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.16-17
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• 2005

Local lifetime control by ion implantation has become an useful tool for production of modern power devices. In this work, punch-through diodes were irradiated with protons for the high speed power diode fabrication. Proton irradiation was executed at the various energy and dose conditions. Characterization of the device was performed by I-V, C-V and Trr measurement. We obtained enhanced reverse recovery time characteristics which was about 45% of original device and about 73% of electron irradiated device. The measurement results showed that proton irradiation was able to effectively reduce minority carrier lifetime.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2089-2091
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• 2000

Pulsed power systems consist of a capacitor bank, an isolated high-voltage charging power-supply, high-current bus-work for charging and discharging and a control system. In such pulsed power systems, the operating-lifetime of the capacitors is closely dependent on the voltage reversal. Hence, most capacitor-discharging systems includes crowbar circuits. The crowbar circuit prevents the capacitor recharging with reverse voltage. Usually it consists of crowbar resistors and high pulse-current diode-stacks connected in series. The requirements for the diode-stacks are fast-recovery time and high-voltage and large-current ratings, which results in the high cost of the pulsed-power system. This paper presents a protection scheme of a charging and discharging system of a 500kJ capacitor bank using a low-cost crowbar circuit and safety-fuses.