• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.551-555
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• 2010

Electrowetting is a versatile tool to handle tiny droplets and forms a backbone of digital microfluidics. Numerical analysis is necessary to fully understand the dynamics of electrowetting, especially in designing electrowetting-based devices, such as liquid lenses and reflective displays. We developed a numerical method to analyze the general contact-line problems, incorporating dynamic contact angle models. The method is based on the conservative level set method to capture the interface of two fluids without loss of mass. We applied the method to the analysis of spreading process of a sessile droplet for step input voltages and oscillation of the droplet for alternating input voltages in electrowetting. The result was compared with experimental data. It is shown that contact line friction significantly affects the contact line motion and the oscillation amplitude. The pinning process of contact line was well represented by including the hysteresis effect in the contact angle models. In level set method, in the mean time, material properties are made to change smoothly across an interface of two materials with different properties by introducing an interpolation or smoothing scheme. So far, the weighted arithmetic mean (WAM) method has been exclusively adopted in level set method, without complete assessment for its validity. We viscosity, thermal conductivity, electrical conductivity, and permittivity, can be an alternative. I.e., the WHM gives more accurate results than the WAM method in certain circumstances. The interpolation scheme should be selected considering various characteristics including type of property, ratio of property of two fluids, geometry of interface, and so on.

• International Journal of Contents
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• v.7 no.3
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• pp.13-18
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• 2011

Oriental medicine statistics are essential in research planning, research evaluation, and policy decision based on objective data. However, integrated administration of such statistics is not presently possible in the oriental medicine field, which has been slow in incorporating information communication technology. In an effort to address this problem, the Korea Institute of Oriental Medicine (KIOM) developed an oriental medicine statistical system in 2009, and the system has been offered in the traditional medicine information portal of OASIS. However, according to a 2010 survey targeting OASIS users, those surveys reported that needs for a system where various statistical data can be extracted via an interactive approach to multidimensional data. As a result of an analysis of the functions of the existing system, it was found that it is necessary to array and arithmetically analyze Stats Value, Drill Up & Drill Down, and Pivot. To this end, the existing DB schema should be redesigned. Based on our analysis result, we redesigned the database into a structure that is applicable to the reverse pivot algorithm. We used J2EE/JSP and a Flex framework to design and develop an oriental medicine statistical system that can provide multidimensional statistical data. Considering that the improved oriental medicine statistical system is planned to be offered by OASIS of KIOM, utilization and value of oriental medicine statistical data are expected to be enhanced.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.284-289
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• 2010

Spectral irradiance of greenhouse covering films that three resins (red, blue, red plus blue) were added to get higher utilization efficiency of sunlight were compared to the normal film in this study. Growth and yield of tomato and pepper grown under the films were also investigated. Transmittance of PAR (photosynthetically active radiation, 400~700 nm) and sunlight (300~1,100 nm) of red or blue resin-added films increased by 5 to 6% and 0.5 to 1.0%, respectively. As compared to the normal film, fruit yield and soluble solid content of tomato and pepper grown under red plus blue resin-added film increased by 15 to 20% and by $0.5^{\circ}Bx$.

• Biomedical Science Letters
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• v.16 no.4
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• pp.365-376
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• 2010

The purpose of this study was to clarify the effect of light emitting diode (LED) irradiation on healing of impaired wound and alteration of mast cells in experimental diabetic rats. Twenty-four male Sprague-Dawley rats were divided into four groups: excision (Ex), excision-LED irradiation (Ex-LED), diabetes + excision (DM) and diabetes + excision + LED irradiation (DM-LED). Diabetes was induced in rats by streptozotocin (STZ) injection (70 mg/kg, single dose) and 6 mm punch excision wounds were created on the back after shaving hair. The LED-irradiated rats were treated to a daily dose of $5\;J/cm^2$ LED (630 nm) light for 11 days after surgery, and were killed at day 1, 3, 7 and 11. The lesion and adjacent skin tissues were excised, fixed with 10% buffered formalin and embedded with paraffin. For evaluation of wound healing, hematoxylin-eosin (HE) and Masson trichrome staining were performed. Mast cells (MCs) were stained with toluidine blue (pH 0.5) and quantified using a computerized image analysis system. The proliferation activity of keratinocyte in skin tissues was analyzed on sections immunostained with proliferative cell nuclear antigen (PCNA). The results showed that wound healing rate, collagen density and neo-epidermis length, number of PCNA-positive cells, fibroblasts and mast cells were significantly higher in the LED-irradiated rats than in the DM and Ex rats throughout the periods of experiment. Exceptionally, the number of MCs was significantly lower at day 11 compared with day 7 after surgery in the all groups. These findings suggest that the LED irradiation may promote the tissue repair process by accelerating keratinocyte and fibroblast proliferation and collagen production in normal rats as well as in diabetic rats, and MCs may play an important role at an early stage of skin wound healing in normal and diabetic rats.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1235-1240
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• 2012

Background: Opisthorchis viverrini infection is a serious public-health problem in Southeast Asia. It is associated with a number of hepatobiliary diseases and the evidence strongly indicates that liver fluke infection is the etiology of cholangiocarcinoma. Objectives: This study aimed to investigate Opisthorchis viverrini metacercarial infection in cyprinoid fish collected from 32 districts of Nakhon Ratchasima province, Northeastern Thailand during one year period from February 2010 to February 2011. Methods: A cross-sectional study was conducted, data being collected with pepsin-HCl digestion and stereomicroscope, respectively. Analysis was performed using SPSS Windows Version 12.0. Results: A total of 640 Cyprinidae family fish including 5 species were collected from different study sites, and investigated for O. viverrini metacercariae. The infection rate was 12.3% (79/640), predominantly in Cyclocheilichthys armatus, C. repasson, Puntioplites proctzysron, Hampala macrolepitota and Hampala dispar, respectively. The prevalence of O. viverrini metaceria in Nakhon Ratchasima area was 78.1%, predominantly in Sida and KiaKham Thale So. Conclusion: This findings stress that natural fish species in rural communities are still a source of O viverrini infection and put local people at risk, therefore public awareness and prevention campaigns are urgently required.

• Archives of Plastic Surgery
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• v.38 no.3
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• pp.300-308
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• 2011

Purpose: The goal of reduction mammaplasty is breast with natural cone shape, minimizing scars, well-placed and sensate nipple-areolar area and maintaining breast physiology. In order to satisfy that goal, variable reduction mammaplasty methods are performed, however, two methods such as vertical reduction method and inverted T-scar method are currently most used. We compared indications and advantages of the two methods and set up useful guidlines. Methods: For 15 years from 1995 to 2010, we experienced 84 patients (162 breasts). We performed vertical reduction method as Lejour's superior pedicle technique (45 patients) and inverted T-scar method as Goldwyn's inferior dermal flap technique (39 patients). We evaluated the result of the operation comparing patient's age, amount of resected tissue, complications and post-operative scars of the two methods. Results: The mean age was 36 years and the vertical reduction group was 3 years younger than inverted T-scar group. The mean breast tissue resection amount per one breast, inverted T-scar group (712 gm) was lagger than vertical reduction group (395 gm). Conclusion: There is no ideal method for reduction mammaplasty until now. However, we suggest that guide line, the vertical reduction method is effective for minimal and moderate macromastia in young and middle aged women and inverted T-scar method is appropriate for severe macromastia with ptosis in elderly women. Recently, all procedures tried shorter and smaller scar on the vertical line as small I, J or L shape scar, and inframammary fold as short inverted T-scar.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.30-30
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• 2010

고강도강의 용접성은 저온균열 저항성으로 대변되는데, TMCP강과 HSLA강 등이 개발되면서 고강도강의 저온균열저항성이 크게 향상되어 무예열 용접성이 확보되었다. 그러나 용접재료 측면에서는 그에 상응하는 재료의 개발이 지연되어 강재 개발로 인한 우수한 성능을 충분히 발휘하지 못하고 있으며 용접부의 건전성 문제가 심각하게 인식되고 있다. 이로 인해 고강도강에 적용시킬 수 있는 무예열 용접재료의 필요성이 대두되어 개발이 진행되고 있으며 상용화를 앞두고 있다. 이러한 용접재료의 개발단계에서 합금설계는 가장 중요한 항목으로 합금 조성에 따라 용착금속의 강도 및 인성에 상당한 변화를 가져오기 때문이다. 합금원소 중 Al은 강재의 탈산을 돕기 때문에 가능한 많은 양의 첨가를 요구하지만 적정량 이상을 초과하게 되면 오히려 용착금속의 저온인성 특성에 부정적인 영향을 미치게 된다. 본 연구에서는 고강도 GMA 용착금속의 Al함량을 단계적으로 변화시켜 용착금속 내 최적의 Al의 함량을 찾고자 하였다. 또한 높은 비용 및 많은 시간을 필요로 하는 와이어로드를 제작하지 않고도 Al함량을 조절 할 수 있는 방법을 고안하고자 하였다. 실험의 모재는 HSLA-100강을 사용하였으며 용접재료는 ER120S-G급의 GMA용접 재료를 사용하였다. 모재 성분과의 희석을 방지하기 위해 V-Groove 가공 후 6패스 Buttering 용접을 실시하였고, 다시 Buttering용접부에 V-Groove 가공을 하여 최종 용접을 실시하였다. 이 때 Al함량을 조절하기 위해 최종 용접 개선부 밑면에 홈을 판 후 Al fiber(직경 0.3mm)를 깔고 용접(입열량 20kJ/cm)하여 Al함유량을 총 3가지(0.003~0.04% Al)로 제어하였다. 용접 후 각각의 시편에 대해 미세조직, 충격시험, O/N분석, 성분분석 등의 시험을 수행하여 저온인성과의 상관관계를 알아보았다.

• Progress in Superconductivity
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• v.11 no.2
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• pp.83-86
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• 2010

There are theoretical and experimental evidences for the pseudo-gap in electron doped cuprates being due to interaction between electrons and anti-ferromagnetism(AFM). A remaining issue is on how AFM correlates with pseudo-gap, and eventually with superconductivity. To elucidate the issue, we have performed temperature dependent angle-resolved photoemission studies of an e-doped cuprate superconductor $Sm_{2-x}Ce_xCuO_4$(SCCO) x=0.18 at 20K and 150K. In the case of $Nd_{2-x}Ce_xCuO_4$, the most well known e-doped cuprate, pseudo-gap disappears at around 100 K for x=0.17. Our experimental result reveals that the pseudo-gap of SCCO exists even at 150K for x=0.18. This result implies that the AFM of SCCO survives even in x=0.18, which agrees with previously reported phase diagram of SCCO. Yet, the superconductivity disappears around x=0.18 for both NCCO and SCCO in spite of the difference in the magnetic order. This result sheds a light on the disappearance of superconductivity on the over-doped side.

• Progress in Superconductivity
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• v.11 no.2
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• pp.152-157
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• 2010

We have fabricated the low noise liquid helium(LHe) dewar with a different shape of thermal shield to apply the 64-channel SQUID(Superconducting Quantum Interference Device) gradiometer. The first shape of thermal shield was made of an aluminum plate with a wide width of 100 mm slit and the other shape was modified with a narrow width of 20 mm slit. The two types of dewars were estimated by comparing the thermal noise and the signal-to-noise ratio(SNR) of magnetocardiography(MCG) using the $1^{st}$ order SQUID gradiometer system cooled each dewar. The white noise was different as a point of the dewar. The noise was increased as close as the edge of dewar, and also increased at the thermal shield with the more wide width slit. The white noise of the dewar with thermal shield of 100 mm slit was 6.5 fT/$Hz^{1/2}$ at the center of dewar and 25 fT/$Hz^{1/2}$ at the edge, and the white noise of the other one was 3.5 - 7 fT/$Hz^{1/2}$. We measured the MCG using 64-channel SQUID gradiometer cooled at each LHe dewar and compared the SNR of MCG signal. The SNR was improved of 10 times at the LHe dewar with a modified thermal shield.

• Progress in Superconductivity
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• v.11 no.2
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• pp.106-111
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• 2010

Sapphire resonators with $YBa_2Cu_3O_{7-\delta}$ (YBCO) endplates have provided a way to realize extremely high quality factor due to the extremely low dielectric loss of sapphire and conductive loss of YBCO films, which enables to measure the low surface resistance of superconductor films at microwave frequencies. We present microwave properties of HTS sapphire resonators designed for measuring the surface resistance of HTS films at millimeter-wave frequencies by using the two-resonance mode dielectric resonator method. Despite enhanced surface resistance ($R_S$) of YBCO films due to the quadratic frequency dependence of the $R_S$, the unloaded quality factor ($Q_0$) of the $TE_{021}$ mode sapphire resonator still appears to be well above $1\;{\times}\;10^6$ at a mm-wave frequency of 38 GHz at 10 K. However, it appears that the $TE_{012}$ mode $Q_0$ is unexpectedly low despite that the corresponding resonance peak looks uncoupled with parasitic modes. We discuss possible reasons for the unexpected results using the surface resistance at the $TE_{021}$, $TE_{012}$, and $TE_{011}$ mode frequencies.