• Applied Chemistry for Engineering
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• v.28 no.2
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• pp.245-251
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• 2017

In this study, ZnO, which is widely known as a non $TiO_2$ photocatalyst, was synthesized using coprecipitation method and Ag was added in order to improve the catalytic performance. The physicochemical characteristics of the synthesized ZnO and Ag/ZnO particles were checked using X-ray diffraction (XRD), UV-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), photoluminescence (PL), and photocurrent measurements. The performance of catalysts was tested by $H_2$ production using the photolysis of $H_2O$ with MeOH. By adding Ag which plays a role as an electron capture on the ZnO catalyst, the performance increased due to the recombination of excited electrons and holes. In particular, $8.60{\mu}mol\;g^{-1}$ $H_2$ was produced after 10 h reaction over the 0.50 mol% Ag/ZnO.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.1003-1007
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• 2013

Objective: This work aimed to investigate the correlations of tumor-associated macrophages (TAMs) and their subtypes M1 and M2 with liver metastasis of colorectal cancer, and provide useful references for seeking predictors of liver metastasis and studying mechanisms. Methods: 120 patients with colorectal cancer from 2000 to 2009 were divided into low, middle and high liver metastasis groups (group A, B and C, respectively). S-P immunohistochemical staining and microscopic observation were conducted to compare expression in CD68-positive cells (TAMs), CD80-positive cells (M1) and CD163-positive cells (M2) in three groups. Correlations of TAMs, M1, M2, and M2/M1 ratio with clinical and pathological parameters were analyzed. Results: With increase of liver metastatic ability, the number of TAMs decreased gradually, with no significant difference between any two of the three groups (P > 0.05), while the numbers of M1 and M2 were significantly decreased and increased, respectively, with significant difference between any two of three groups (P < 0.05 or P < 0.01). In addition, the M2/M1 ratio increased with increase of liver metastatic ability (P < 0.01). There was no statistical significance of correlation of TAMs with each clinical and pathological parameter. M1 was negatively related with lymphatic metastasis and liver metastatic ability. M2 was positively correlated with preoperative CEA level, lymphatic metastasis, tumor differentiation degree and liver metastatic ability. The same was the case for the M2/M1 ratio. Conclusions: Effects of TAMs on liver metastasis of colorectal cancer do not depend on the total number of TAMs, but on the number and proportion of functional subtypes M1 and M2. M2 number and M2/M1 ratio are more accurate predictors for liver metastasis of colorectal cancer.

• The Journal of the Acoustical Society of Korea
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• v.19 no.4
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• pp.45-51
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• 2000

This paper describes real-time implementation of a multi-channel G.729A speech coder using a 16 bit fixed-point Digital Signal Processor (DSP) and its application to a Voice Mailing Service (VMS) system. TMS320C549 by Texas Instruments was used as a fixed point DSP chip and a 4 channel G.729A coder was implemented on the chip. The implemented coder required 14.5 MIPS for the encoder and 3.6 MIPS for the decoder at each channel. In addition, memories required by the coder were 9.88K words and 1.69K words for code and data sections, respectively. As a result, the developed VMS system that accommodates two DSP chips was able to support totally 8 channels. Experimental results showed that the our multi-channel coder passes all of test vectors provided by ITU-T.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.373-373
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• 2014

Resistive-change random access memory (ReRAM) device is one of the promising candidates owing to its simple structure, high scalability potential and low power operation. Many resistive switching devices using transition metal oxides materials such as NiO, Al2O3, ZnO, HfO2, $TiO_2$, have attracting increased attention in recent years as the next-generation nonvolatile memory. Among various transition metal oxides materials, HfO2 has been adopted as the gate dielectric in advanced Si devices. For this reason, it is advantageous to develop an HfO2-based ReRAM devices to leverage its compatibility with Si. However, the annealing temperature of these high-k thin films for a suitable resistive memory switching is high, so there are several reports for low temperature process including microwave irradiation. In this paper, we demonstrate the bipolar resistive switching characteristics in the microwave irradiation annealing processed Ag/HfO2/Pt ReRAM device. Compared to the as-deposited Ag/HfO2/Pt device, highly improved uniformity of resistance values and operating voltage were obtained from the micro wave annealing processed HfO2 ReRAM device. In addition, a stable DC endurance (>100 cycles) and a high data retention (>104 sec) were achieved.

• Journal of KIISE:Databases
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• v.29 no.6
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• pp.477-491
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• 2002

The broadcast environment has asymmetric communication aspect that is typically much greater communication bandwidth available from server to clients than in the opposite direction. In addition, mobile computing systems generate mostly read-only transactions from mobile clients for retrieving different types of information such as stock data, traffic information and news updates. Since previous concurrency control protocols, however, do not consider such a particular characteristics, the performance degradation occurs when previous schemes are applied to the broadcast environment. In this paper, we propose optimistic concurrency control based on timestamp interval for broadcast environment. The following requirements are satisfied by adapting weak consistency that is the appropriate correctness criterion of read-only transactions: (1) the mutual consistency of data maintained by the server and read by clients (2) the currency of data read by clients. We also adopt the timestamp Interval protocol to check the weak consistency efficiently. As a result, we improved a performance by reducing unnecessary aborts and restarts of read-only transactions caused when global serializability was adopted.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.227-230
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• 1990

The addition of titanium has come to produce an increase in the conductivity of ${\alpha}-Fe_2O_3$ and has been shown NTC ( negative temperature coefficient ) characteristics. Titanium enters the ${\alpha}-Fe_2O_3$ lattice substitutionally as $Ti^{4+}$,thus producing an $Fe^{2+}$ and maintaining the average charge per cation at three. Thus the $Fe^{2+}$ acts as a donor center with respect to the surrounding $Fe^{3+}$ ions. The sintering temperature, compacting pressure and sintering tire have an effect on the electrical properties. C-V and other properties have been measured on polycrystalline samples of ${\alpha}-Fe_2O_3$ containing small deviations from stoichiometry and small amounts of added Titanium. This measurment was made in the course of an investigation of the NTC mechanism in oxides whose cations have a partially filled d-level. C-V and frequency properties have been applied to the measurement of the trap barrier properties at the grain boundary. The double Schottky barrier at the grain boundary is the major cause of the NTC mechanism in NTC thermistor of ${\alpha}-Fe_2O_3$ containing N-type impurity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.290-293
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• 2003

Ohmic contact characteristics of Al ion implanted n-type SiC wafer were investigated. Al ions implanted with high dose to obtain the final concentration of $5{\times}10^{19}/cm^3$, then annealed at high temperature. Firstly, B ion ion implanted p-well region were formed which is needed for fabrication of SiC devices such as DIMOSFET and un diode. Secondly, Al implanted high dose region for ohmic contact were formed. After ion implantation, the samples were annealed at high temperature up to $1600^{\circ}C\;and\;1700^{\circ}C$ for 30 min in order to activate the implanted ions electrically. Both the inear TLM and circular TLM method were used for characterization. Ni/Ti metal layer was used for contact metal which is widely used in fabrication of ohmic contacts for n-type SiC. The metal layer was deposited by using RF sputtering and rapid thermal annealed at $950^{\circ}C$ for 90sec. Good ohmic contact characteristics could be obtained regardless of measuring methods. The measured specific contact resistivity for the samples annealed at $1600^{\circ}C\;and\;1700^{\circ}C$ were $1.8{\times}10^{-3}{\Omega}cm^2$, $5.6{\times}10^{-5}{\Omega}cm^2$, respectively. Using the same metal and same process of the ohmic contacts in n-type SiC, it is found possible to make a good ohmic contacts to p-type SiC. It is very helpful for fabricating a integrated SiC devices. In addition, we obtained that the ratio of the electrically activated ions to the implanted Al ions were 10% and 60% for the samples annealed at $1600^{\circ}C\;and\;1700^{\circ}C$, respectively.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1999.10a
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• pp.56-56
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• 1999

For advanced TFT-LCD manufacturing processes, dry etching of thin-film layers(a-Si, $SiN_x$, SID & gate electrodes, ITO etc.) is increasingly preferred instead of conventional wet etching processes. To dry etch Al gate electrode which is advantageous for reducing propagation delay time of scan signals, high etch rate, slope angle control, and etch uniformity are required. For the Al gate electrode, some metals such as Ti and Nd are added in Al to prevent hillocks during post-annealing processes in addition to gaining low-resistivity($<10u{\Omega}{\cdot}cm$), high performance to heat tolerance and corrosion tolerance of Al thin films. In the case of AI-Nd alloy films, however, low etch rate and poor selectivity over photoresist are remained as a problem. In this study, to enhance the etch rates together with etch uniformity of AI-Nd alloys, magnetized inductively coupled plasma(MICP) have been used instead of conventional ICP and the effects of various magnets and processes conditions have been studied. MICP was consisted of fourteen pairs of permanent magnets arranged along the inside of chamber wall and also a Helmholtz type axial electromagnets was located outside the chamber. Gas combinations of $Cl_2,{\;}BCl_3$, and HBr were used with pressures between 5mTorr and 30mTorr, rf-bias voltages from -50Vto -200V, and inductive powers from 400W to 800W. In the case of $Cl_2/BCl_3$ plasma chemistry, the etch rate of AI-Nd films and etch selectivity over photoresist increased with $BCl_3$ rich etch chemistries for both with and without the magnets. The highest etch rate of $1,000{\AA}/min$, however, could be obtained with the magnets(both the multi-dipole magnets and the electromagnets). Under an optimized electromagnetic strength, etch uniformity of less than 5% also could be obtained under the above conditions.

• The Journal of Pediatrics of Korean Medicine
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• v.24 no.1
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• pp.104-116
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• 2010

Objectives The Medical record consist of symptoms, the cause of a disease, diagnostic studies, medical treatment, prescription, and so on. Doctors can use medical records as data for diagnosis, treatment, and education. Therefore, medical records are beneficial. Methods Translating $\ll$Xiao Er Yao Zheng Zhi Jue$\gg$ into modern Korean, and studying the medical records of Qian Yi(錢乙)'s Medical concept in $\ll$Xiao Er Yao Zheng Zhi Jue$\gg$ were examined. Results Regarding the diagnosis of the pediatric diseases, Si Zhen He Can(四該合參), consider in the eye exam closely. In addition, he closely combined the concept of Wu Zang Bian Zheng(五藏辨證), and diagnosis the pediatric diseases. Wu Zang Bian Zheng(五藏辨證). what Qian-Yi(錢乙) established method was based on Zheng Ti Guan(整體觀) in Huang Di Nei Jing(黃帝內經). Qian-Yi(錢乙) took a close look on Chuang Zhen(瘡疹) which had been an inadequate field in those days. He criticized on the habitual misuse of medications. He treated Ji Jing(急驚) and Man Jing(慢驚) separately; Ji Jing(急驚) as Liang Xie(凉瀉) and Man Jing(慢驚) as Wen Bu(溫補). He proposed Zong Gan Zhu Feng and Xin Zhu Jing(縱肝主風, 心主驚) theory and formulated Jing Feng(驚風) theory as well. He emphasized the treatment to Gong Bu Shang Zheng, Bu Bu Zhi Xie, Xiao Bu Jian Shi(攻不傷正, 補不滯邪, 消補兼施) because he had a clear demonstration to Han Re Xu Shi(寒熱虛實) of the five viscera in the field of Fang yao(方藥). Conclusions Understanding $\ll$Xiao Er Yao Zheng Zhi Jue$\gg$ and its medical records of Qian Yi(錢乙)'s medical concept had quintessential meaning to both modern pediatrician and oriental medical doctors of all medical fields in treating children.

• Journal of Energy Engineering
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• v.28 no.4
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• pp.8-12
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• 2019

Thermal amine scrubbing is the most advanced CO₂ capture technique but its largescale application is hindered due to the large heat requirement during solvent regeneration step. The addition of a solid metal oxide catalysts can optimize the CO₂ desorption rate and thus minimize the energy consumption. Herein, we evaluate the solvent regeneration performance of Monoethanolamine (MEA) and Diethanolamine (DEA) solvents without and with two metal oxide catalysts (TiO₂ and V₂O₅) within a temperature range of 40-86℃. The solvent regeneration performance was evaluated in terms of CO₂ desorption rate and overall amount of CO₂ desorbed during the experiments. Both catalysts improved the solvent regeneration performance by desorbing greater amounts of CO₂ with higher CO₂ desorption rates at low temperature. Improvements of 86% and 50% in the CO₂ desorption rate were made by the catalysts for MEA and DEA solvents, respectively. The total amount of the desorbed CO₂ also improved by 17% and 13% from MEA and DEA solvents, respectively. The metal oxide catalyst-aided regeneration of amine solutions can be a new approach to minimize the heat requirement during solvent regeneration and thus can remove a primary shortfall of this technology.