• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.443-455
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• 2013

Electrochemical studies on charge transfer reactions across the interface between two immiscible electrolyte solutions (ITIES) have greatly attracted researcher's attentions due to their wide applicability in research fields such as ion sensing and biosensing, modeling of biomembranes, pharmacokinetics, phase-transfer catalysis, fuel generation and solar energy conversion. In particular, there have been extensive efforts made on developing sensing platforms for ionic species and biomolecules via gelifying one of the liquid phases to improve mechanical stability in addition to creating microscale interfaces to reduce ohmic loss. In this review, we will mainly discuss on the basic principles, applications and future aspects of various sensing platforms utilizing ion transfer reactions across the ITIES. The ITIES is classified into four types : (i) a conventional liquid/liquid interface, (ii) a micropipette supported liquid/liquid interface, (iii) a single microhole or an array of microholes supported liquid/ liquid interface on a thin polymer film, and (iv) a microhole array liquid/liquid interface on a silicon membrane. Research efforts on developing ion selective sensors for water pollutants as well as biomolecule sensors will be highlighted based on the use of direct and assisted ion transfer reactions across these different ITIES configurations.

• Korean Journal of Optics and Photonics
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• v.17 no.1
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• pp.94-98
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• 2006

An optical microphone based on a dual-core fiber collimator and a membrane type micromirror serving as an optical head and a reflective diaphragm respectively was implemented. The micromirror diaphragm is suspended by a thin silicon bar linked with a frame, thus it is subject to a displacement induced by acoustic waves. The optical head incorporating two collimators integrated in a single housing gives light to and receives it from the diaphragm, rendering the optical microphone structure simple and compact. This dual-core collimator having a slowing varying beam profile facilitates the initial alignment of the optical head with the diaphragm, especially the distance between them. For the assembled microphone, the static characteristics were investigated tofind the operation point defined as the optimum distance between the head and the diaphragm, and a frequency response with a variation of about $\pm$5 dB for the range of up to 3kHz was achieved.

• Parasites, Hosts and Diseases
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• v.49 no.2
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• pp.115-123
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• 2011

Toxoplasma gondii Korean isolate (KI-1) tachyzoites were inoculated intraduodenally to BALB/c mice using a silicon tube, and the course of infection and immune responses of mice were studied. Whereas control mice, that were infected intraperitoneally, died within day 7 post-infection (PI), the intraduodenally infected mice survived until day 9 PI (infection with $1{\times}10^5$ tachyzoites) or day 11 PI (with $1{\times}10^6$ tachyzoites). Based on histopathologic (Giemsa stain) and PCR (B1 gene) studies, it was suggested that tachyzoites, after entering the small intestine, invaded into endothelial cells, divided there, and propagated to other organs. PCR appeared to be more sensitive than histopathology to detect infected organs and tissues. The organisms spread over multiple organs by day 6 PI. However, proliferative responses of splenocytes and mesenteric lymph node (MLN) cells in response to con A or Toxoplasma lysate antigen decreased significantly, suggesting immunosuppression. Splenic $CD4^+$ and $CD8^+$ T-Iymphocytes showed decreases in number until day 9 PI, whereas IFN-${\gamma}$ and IL-10 decreased slightly at day 6 PI and returned to normal levels by day 9 PI. No TNF-${\alpha}$ was detected throughout the experimental period. The results showed that intraduodenal infection with KI-1 tachyzoites was successful but did not elicit significant mucosal immunity in mice and allowed dissemination of T. gondii organisms to systemic organs. The immunosuppression of mice included reduced lymphoproliferative responses to splenocytes and MLN cells to mitogen and low production of cytokines, such as IFN-${\gamma}$, TNF-${\alpha}$, and IL-10, in response to T. gondii infection.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.1
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• pp.78-82
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• 2005

Display manufacturing process has adopted RCA cleaning, applying to larger area and coping with environmental issue for last ten years. However, the approaching concept of ozonized, hydrogenised, or electrolyzed water cleaning technologies is within RCA clean paradigm. In this work, only electrolyzed anode water was applied to clean particles and organics as well as metals based on Pourbaix concept, and as a test vehicle, MgO particles were introduced to prove the new concept. The electrolyzed anode water is very oxidative with high oxidation reduction potential (ORP) and low in pH of more than 900 mV and 3.1, respectively. MgO particles were immersed in the anode water and its weight losses due to dissolution were measured with time. Weight losses were in the ranges of 100 to 500 micrograms in 250 ml anode water depending on their ORP and pH. Therefore it was concluded that the cleaning radicals in the anode water was at least in the range of 1 to $5{\times}10^{20}$ ea per 250 ml anode water equivalent to $1{\times}10^{18} ea/cm^2$. Hence it can be assumed that the anode water applied to display cleaning from now on $1{\times}10^{10}$ to $1{\times}10^{15} ea/cm^2$ ranges of contaminants are being treated. In addition, it was observed that anode water did not develop micro-roughness on hydrophobic surface while it did on the native silicon oxide.

• Journal of Surface Science and Engineering
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• v.29 no.6
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• pp.809-815
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• 1996

$Y_2O_3$-based metal-insulator-semiconductor (MIS) structure on p-Si(100) has been studied. Films were prepared by UHV reactive ionized cluster beam deposition (r-ICBD) system. The base pressure of the system was about $1 \times 10^{-9}$ -9/ Torr and the process pressure $2 \times 10^{-5}$ Torr in oxygen ambience. Glancing X-ray diffraction(GXRD) and in-situ reflection high energy electron diffracton(RHEED) analyses were performed to investigate the crystallinity of the films. The results show phase change from amorphous state to crystalline one with increasingqr acceleration voltage and substrate temperature. It is also found that the phase transformation from $Y_2O_3$(111)//Si(100) to $Y_2O_3$(110)//Si(100) in growing directions takes place between $500^{\circ}C$ and $700^{\circ}C$. Especially as acceleration voltage is increased, preferentially oriented crystallinity was increased. Finally under the condition of above substrate temperature $700^{\circ}C$ and acceleration voltage 5kV, the $Y_2O_3$films are found to be grown epitaxially in direction of $Y_2O_3$(1l0)//Si(100) by observation of transmission electron microscope(TEM). Capacitance-voltage and current-voltage measurements were conducted to characterize Al/$Y_2O_3$/Si MIS structure with varying acceleration voltage and substrate temperature. Deposited $Y_2O_3$ films of thickness of nearly 300$\AA$ show that the breakdown field increases to 7~8MV /cm at the same conditon of epitaxial growing. These results also coincide with XPS spectra which indicate better stoichiometric characteristic in the condition of better crystalline one. After oxidation the breakdown field increases to 13MV /cm because the MIS structure contains interface silicon oxide of about 30$\AA$. In this case the dielectric constant of only $Y_2O_3$ layer is found to be $\in$15.6. These results have demonstrated the potential of using yttrium oxide for future VLSI/ULSI gate insulator applications.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.12
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• pp.668-673
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• 2015

Alumina-based catalysts with different Ce loadings were studied in the decomposition of $CF_4$ using microwave heating system. Heating material of microwave system used Silicon Carbide. The crystallographic phases of catalysts were investigated by XRD and decomposition rates of $CF_4$ were examined by GC-TCD. The catalysts of 10 wt% Ce modified $Al_2O_3$ showed higher $CF_4$ decomposition rate than un-modified $Al_2O_3$ for $500^{\circ}C$ reaction temperature. The k value of catalysts shows the order of $Ce(20)/Al_2O_3=Ce(0)/Al_2O_3<Ce(5)/Al_2O_3<Ce(10)/Al_2O_3$. XRD patterns of $Ce(0)/Al_2O_3$ were no difference before and after the reaction and showed $Al_2O_3$ phases. With the increase in Ce loadings, $CeO_2$, $AlF_3$ of XRD peaks was observed. The results was indicated that Ce modifed $Al_2O_3$ than un-modifed $Al_2O_3$ was decreased reaction temperature to $200^{\circ}C$ with same decomposition rate. Also the appropriated cerium sulfate loadings on $Al_2O_3$ were 5~10 wt%.

• Journal of Korea Technology Innovation Society
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• v.16 no.2
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• pp.476-505
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• 2013

Korea government has established and pursued green technology development strategy as the core of green growth, for example, withdrawal of 27 key green technologies through 'green technology research and development comprehensive plan ('09.1)' since 'low carbon green growth' was proposed as a new national development paradigm. In this study, we performed the Delphi survey of technology levels of 131 strategic product and service technologies derived from 27 key green technologies, utilizing large-scale group of green technology experts. The survey of technology level among main five nations resulted in the world's leading nation (US) versus EU (99.4%), Japan (95.3%), Korea (77.7%), China (67.1%) and Korea was ranked fourth. The technology gap between the world's leading nation (US) and Korea is 4.1 years behind EU (3.9 years) and Japan(3.1 years), but 2.1 years earlier than China. For our nation, key green technologies with high technology level are 'improved light water reactor (90.1%)', 'silicon-based solar cell (85.0%)', 'high-efficiency low-emission car (84.5%)' in order. Depending on the investment type of key green technologies, technology level is represented as short-term (85.0%), mid-term (77.3%) and long-term (71.1%) in order, indicating that lower technology level requires mid-to long-term investment and that the investment type is set appropriate.

• Archives of Plastic Surgery
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• v.36 no.4
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• pp.437-444
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• 2009

Purpose: Transgender is a disorder of gender identity, who have appropriate chromosomal, hormonal and anatomical characteristics corresponding to their sexual phenotype but feel strongly with respect to their sexual identity, that they belong to the opposite sex. There is a persistence discomfort and sense of inappropriateness about one's assigned sex in a person who has reached puberty. Transgender is a psychiatric problem, but surgical method provides more satisfactory adjustment for patients. In gender reassignment surgery for female to male transgender, mastectomy, nipple reduction, hysterectomy, oophorectomy and phalloplasty are included. And as the final operation, recommended for scrotoplasty and artificial testes insertion. So we investigated the necessity and method of scrotoplasty in the final operation of female to male transgender. Method: The authors have long term follow-up of 75 cases female to male transgender during January, 1991 to February, 2008. Among them, 13 cases were evaluated in this study. During phalloplasty, the labium major skin preserved. And this labium majoral skin flap was made for the neoscrotum. At least six months later, artificial testes were inserted in neoscrotum with local anesthesia. Middle sized (3 cm diameter) artificial testes(silicon gel or carving soft silicone implant) were used because of the limitation of the neoscrotum. We evaluated the questionnaire and interview about the postoperative satisfaction in configuration of reconstructed scrotum, and the necessity of operation, the postoperative psychosocioeconomic improvement and limitation of body exposure activities such as swimming, public bathing. Results: Based on this study, satisfaction of reconstructed scrotum after scrotoplasty was improved(92%). The necessity of scrotoplasty was in 92.3% and the postoperative psychosocioeconomic well - being improvement was 77% in answers. Less limitation of activities requiring body exposure was 54% in answers. Most of the patients were satisfied with the results of surgical operation inspite of the operative procedure had some postoperative complications. Conclusion: This study was reported that the scrotoplasty in female to male transgender is not only a conversion of external genitalia but also an improvement of psychosocial state. Most patients sincerely hope to this operation, so we improve our surgical method for more good results.

• Journal of radiological science and technology
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• v.39 no.4
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• pp.595-600
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• 2016

The diagnostic multileaf collimator(MLC) was designed for patient dose reduction in diagnostic radiography We used monte carlo simulation code (MCNPX, LANL, USA) to evaluate efficiency of shielding material for making diagnostic MLC as preliminary study. The diagnostic radiography unit was designed using SRS-78 program according to tube voltage (80,100,120 kVp) and acquired energy spectrums. The shielding material was SKD11 alloy tool steel that is composed of 1.6% carbon(C), 0.4% silicon(Si), 0.6% manganese (Mn), 5% chromium (Cr), 1% molybdenum(Mo) and vanadium(V). The density of it was $7.89g/cm^3$.Using tally card 6, we calculated the shielding efficiency of MLC according to tube voltage. The results was that 98.3% (80 kVp), 95.7 %(100 kVp), 93.6% (120 kVp). We certified efficiency of diagnostic MLC fabricated from SKD11 alloy steel by monte calro simulation. Based on the results, we designed the diagnostic MLC and will develop the diagnostic MLC for reduction of patient dose in diagnostic radiography.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.170-170
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• 2010

Thin-film transistors (TFT) have become the key components of electronic and optoelectronic devices. Most conventional thin-film field-effect transistors in display applications use an amorphous or polycrystal Si:H layer as the channel. This silicon layers are opaque in the visible range and severely restrict the amount of light detected by the observer due to its bandgap energy smaller than the visible light. Therefore, Si:H TFT devices reduce the efficiency of light transmittance and brightness. One method to increase the efficiency is to use the transparent oxides for the channel, electrode, and gate insulator. The development of transparent oxides for the components of thin-film field-effect transistors and the room-temperature fabrication with low voltage operations of the devices can offer the flexibility in designing the devices and contribute to the progress of next generation display technologies based on transparent displays and flexible displays. In this thesis, I report on the dc performance of transparent thin-film transistors using amorphous indium tin zinc oxides for an active layer. $SiO_2$ was employed as the gate dielectric oxide. The amorphous indium tin zinc oxides were deposited by RF magnetron sputtering. The carrier concentration of amorphous indium tin zinc oxides was controlled by oxygen pressure in the sputtering ambient. Devices are realized that display a threshold voltage of 4.17V and an on/off ration of ${\sim}10^9$ operated as an n-type enhancement mode with saturation mobility with $15.8\;cm^2/Vs$. In conclusion, the fabrication and characterization of thin-film transistors using amorphous indium tin zinc oxides for an active layer were reported. The devices were fabricated at room temperature by RF magnetron sputtering. The operation of the devices was an n-type enhancement mode with good saturation characteristics.