• Journal of IKEEE
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• v.23 no.1
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• pp.193-199
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• 2019

In this study, we have proposed a floating metal guard ring structure based on TCAD simulation in order to enhance the breakdown voltage characteristics of gallium oxide ($Ga_2O_3$) vertical high voltage switching Schottky barrier diode. Unlike conventional guard ring structures, the floating metal guard rings do not require an ion implantation process. The locally enhanced high electric field at the anode corner was successfully suppressed by the metal guard rings, resulting in breakdown voltage enhancement. The number of guard rings and their width and spacing were varied for structural optimization during which the current-voltage characteristics and internal electric field and potential distributions were carefully investigated. For an n-type drift layer with a doping concentration of $5{\times}10^{16}cm^{-3}$ and a thickness of $5{\mu}m$, the optimum guard ring structure had 5 guard rings with an individual ring width of $1.5{\mu}m$ and a spacing of $0.2{\mu}m$ between rings. The breakdown voltage was increased from 940 V to 2000 V without degradation of on-resistance by employing the optimum guard ring structure. The proposed floating metal guard ring structure can improve the device performance without requiring an additional fabrication step.

• Journal of the Korean Geosynthetics Society
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• v.7 no.3
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• pp.17-24
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• 2008

This study is conducted to investigate the possibility of the utilization of the mixed soil formed by mixing stone sludge, bentonite, and residual soil as a soil sealant sustaining both stability and capacity in the barrier system. A series of tests were performed on the mixed soils to evaluate basic properties such as compaction, compressive strength, permeability and CBR of these materials. The results indicates that as the stone sludge content increases, the optimum moisture content increases a little, but the maximum dry density decreases. The compressive strength and CBR decrease, and the cohesion, internal friction angle and expansion ratio increase. When the bentonite content increases, the maximum dry density decreases, and the optimum moisture content, compressive strength and cohesion, internal friction angle, CBR and expansion ratio increase. Mixing ratio of the mixed soil contained with the stone dust more than 10% and the bentonite less than 10% satisfies the standard of the permeability coefficient as the soil sealant.

• Journal of Acupuncture Research
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• v.24 no.6
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• pp.137-148
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• 2007

Objectives : Following central nervous system (CNS) injury, inhibitory influences at the site of axonal damage occur. Glial cells become reactive and form a glial scar, know as gliosis. As well,myelin debris such as MAG inhibits axonal regeneration. Astrocyte-rich gliosis relates to up-regulation of GFAP and CD81, and eventually becomes a physical and mechanical barrier to axonal regeneration. It is postulated that when the astrocytic reaction is absent, regeneration of axons can occur. It was reported that treatment with anti CD81 antibodies enhanced functional recovery in rats with spinal cord injury. Methods : MAG is one of several endogenous axon regeneration inhibitors that limit recovery from central nervous system injury and disease. It was reported that molecules which block such inhibitors enhanced axon regeneration and functional recovery. Results : In this current study, the author investigated the effect of the water extract of Ginseng Radix on the regulation of CD81, GFAP and MAG which increases when gliosis occurs. MTT analysis was performed to examine cell viability, and cell based ELISA, Western Blot and PCR were used to detect the expression of CD81, GFAP and MAG. Immunohistochemistry was also performed to confirm in vivo. Conclusions : We observed that Ginseng Radix significantly down-regulates the expression of CD81, GFAP and MAG by means of cell based ELISA, Western Blot and PCR. In immunohistochemistry, expression of CD81, GFAP and MAG also decreased. Taken together, these results suggest that Ginseng Radix can be a candidate for regenerating CNS injury.

• Korean journal of communication and information
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• v.31
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• pp.167-192
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• 2005

How to facilitate Integrated Marketing Communication (IMC)? An approach to answer this question is to identify an organization's internal and external barriers to IMC and then to resolve them. Eight dimensions emerged from the factor analysis of the barrier items: organizational structure problem, department ego, lack of database, difficulty in analyzing effectiveness, lack of perception on consumer-oriented communication, increasing dependency on an agency, lack of agencies' expertise on IMC, and fear of budget reductions. With regression analyses, this study found that 'organizational structure problem' and 'lack of perception on consumer-oriented communication' were negatively related to IMC and that 'department ego', 'lark of perception on consumer-oriented Communication', 'organizational structure problem', and 'fear of budget reductions' were negatively related to the expectation of IMC usefulness. The findings indicate that organizations surveyed stay at a low level of IMC and urgently needs to resolve internal barriers rather than external ones in order to enhance IMC.

• The Korean Journal of Emergency Medical Services
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• v.6 no.1
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• pp.87-102
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• 2002

Injury has now replaced disease as the biggest single cause of death in children after their first birthday. Each day child dies from preventable, unintentional injury and the medical cost of these injury is increasing remarkably. It is necessary to develope injury prevention models to explain, predict, manage, evaluate and analyze the information about accident. The purpose of this paper is, firstly, to investigate parent's actions regarding safety measures at home and secondly, to identify the influencing factors of parents' safety behaviors. The selection of such factors is guided by the theoretical framework of the Pender's Health Promotion Model. Method ; The questionnaire was developed on the basis of other investigations, through pilot testing, peer review, and review by field health workers. The questionnaire was completed by 231 mothers of young children. Data was collected between April and May 2002. Variable Use of three different domains of safety behavior, safety habits, supervision and perception of safety devices, were listed. Mothers were self reported on internal locus of control, mother & child relationships, and marital intimacy. Also the elements of the Health Promotion Model: perceived benefit, barrier, threat, and self-efficacy, were surveyed. Results & discussion The results indicate that most parents take considerable action to reduce household hazards. The constructs derived from the Model were statistically significant differences for a small part of the variables on parental behavior to reduce hazards in the home, such as age, education, economic status, self-efficacy, perceived benefit, internal locus of control. Future studies ought to include social influences, such as expectations, perceived norms, knowledge, and child-related variables, relevant to parental safety measures in their home.

• The Journal of Internal Korean Medicine
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• v.21 no.4
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• pp.615-619
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• 2000

Objective : The prostatic disease is characterized as relatively incurable, chronic and recurrent illness. Because of this property, we have the difficulty in treating this illness. Besides, the drug selectivity is restricted to the specific prostatic membrane, the barrier of prostate. This study was to evaluate the efficency of the activating blood flow and removing blood stasis Method to Prostatic disease. Methods : We investigated 51 prostatic patiens with NIH chronic prostatitis symptom index, digital rectal examination(DRE), expressed prostatic secretion(EPS). After investigation we treated the patients with herb which was aimed to activate the blood flow and remove the blood stasis method to prostatic disease. Results : After the treatment, symptom index score of the prostatic patients was reduced from 11.7 to 7.4. The cure rate of 51 prostatic patients was 76.5%. Also the cure rate of the patients who was treated over 4 weeks was higher than the patients treated below 4 weeks, 87.5% to 66.7% respectively. conclusions : These results indicate that oriental medical theraphy is useful enough to treat the prostatic patients. Therefore, the more research about the herb which has activating blood flow and removing blood stasis effect is necessary.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.1009-1016
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• 2013

Background: The benefits of physical activity are well established and recognized to prevent adults from many chronic diseases and particularly some forms of cancers. Objectives: The present study was conducted to investigate the present status of physical activity among Saudi adults in Al-Ahsa, and to examine the association between the stages of change for physical activity and perceived barriers, and self efficacy. Methods: A cross-sectional study of 242 subjects (118 males and 124 females) attending health centers aged between 20-56 years, were personally interviewed for demographic data, anthropometric measurement, physical activity level, stages of change for physical activity, self efficacy and perceived barriers. Results: Forty eight percent of the females were overweight and 16.9% of the males were obese with no significant difference between the genders for BMI categories. More than half of the females were inactive and 39% of the males were physically active with a significant difference (P=0.007). Twenty percent of the males were in maintenance stage, while similar percentage of the females were in contemplation stage. However the majority of the subjects were in pre-contemplation stage with a significant difference across the stages. Males had a higher mean score of self efficacy and less external barriers of physical activity. The major barrier among the females was lack of time ($7.2{\pm}1.4$) and in the males, lack of motivation ($7.7{\pm}1.4$). The females had less internal ($21.2{\pm}3.8$) barriers comparable to the males ($23.08{\pm}4.7$). Both genders had a significant relationship between stages of changes of physical activity and perceived barriers (internal and external), but in the females no significant difference across the stages was observed for self efficacy unlike the males who had a significant difference for self efficacy and self efficacy categories. Conclusion: The present study provided useful data on stages of change for physical activity and some psychosocial factors (self efficacy and perceived barriers) that can help to tailor strategies aiming at increasing physical activity level according to self efficacy and to the barriers detected, to prevent many chronic diseases including certain types of cancer in Saudi Arabia.

• Korean Journal of Veterinary Research
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• v.32 no.4
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• pp.543-553
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• 1992

Properties of unitary ATP-sensitive $K^+$ channels were studied using planar lipid bilayer technique. Vesicles were prepared from bullfrog (Rana catesbeiana) skeletal muscle. ATP-sensitive $K^+$ (K (ATP)) channels were identified by their unitary conductance and sensitivity to ATP. In the symmetrical solution containing 200mM KCI, 10mM Hepes, 1mM EGTA and pH 7.2, single K (ATP) channels showed a linear current-voltage relations with slight inward rectification. Slope conductance at reversal potential was $60.1{\pm}0.43$ pS(n=3)). Micromolar ATP reversibly inhibited the channel activity when applied to the cytoplasmic side. In the range of -50~＋50 mV, the channel activity was not voltage-dependent, but the channel gating within a burst was more frequent at negative voltage range. Varying the concentrations of external/internal KCl(mM) to 40/200, 200/200, 200/100 and 200/40 shifted reversal potentials to $-30.8{\pm}2.9$(n=3), $-1.1{\pm}2.7$(n=3), 10.5 and 30.6(mV), respecrivety. These reversal potentials were close to the expected values by the Nernst equation, indicating nearly ideal selectivity for $K^+$ over $Cl^-$. Under bi-ionic conditions of 200mM external test ions and 200mM internal $K^+$, the reversal potentials for each test ion/K pair were measured. The measured reversal potentials were used for the calculation of the releative permeability of alkali cations to $K^+$ ions using the Goldman-Hodgkin-Katz equation. The permeability sequence of 5 cations relative to $K^+$ was $K^+$(1), $Rb^+$(0.49), $Cs^+$(0.27), $Na^+$(0.027) and $Li^+$(0.021). This sequence was recognized as Eisenman's selectivity sequence IV. In addition, modelling the permeation of $K^+$ ion through ATP-sensitive $K^+$ channel revealed that a 3-barrier 2-site multiple occupancy model can reasonably predict the observed current-voltage relations.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.700-702
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• 2005

A 5.0-inch transmissive type plastic TFT arrays were successfully fabricated on a plastic substrate at the resolution of $400{\times}3{\times}300$ lines (100ppi). All of the TFT processes were carried out below $150^{\circ}C$ on PES plastic films. After thin film deposition using PECVD, thin film failures such as film delamination and cracking often occurred. For successful growth of thin films (about 1um) without their failures, it is necessary to solve the critical problem related to the internal compressive stress (some GPa) leading to delamination at a threshold thickness value of the films. The Griffith's theory explains the failure process by looking at the excess of elastic energy inside the film, which overcomes the cohesive energy between film and substrate. To increase the above mentioned threshold thickness value there are two possibilities: (i) the improvement of the interface adhesion (for example, through surface micro-roughening and/or surface activation), and (ii) the reduction of the internal stress. In this work, reducing a-Si layer film thickness and optimizing a barrier SiNx layer have produced stable CVD films at 150oC, over PES substrates

• Journal of the Korean Solar Energy Society
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• v.37 no.4
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• pp.35-47
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• 2017

Energy efficiency solutions are being pursued as a sustainable approach to reducing energy consumption and related gas emissions across various sectors of the economy. Vacuum Insulation Panel (VIP) is an energy efficient advanced insulation system that facilitates slim but high-performance insulation, based on a porous core material evacuated and encapsulated in a barrier envelope. Although VIP has been applied in buildings for over a decade, it wasn't until recently that efforts have been initiated to propose and adopt a global standard on characterization and testing of VIP. One of the issues regarding VIP is its durability and aging due to pressure and moisture dependent increase of the initial low thermal conductivity with time; more so in building applications. In this paper, the aging of commercially available VIP was investigated experimentally; thermal conductivity was tested in accordance with ISO 8302 standard (guarded hot box method) and long-term durability was estimated based on a non-linear pressure-humidity dependent equation based on study of IEA/ECBCS Annex 39, with the aim of assessing durability of VIP for use in buildings. The center-of-panel thermal conductivity after 25 years based on initial 90% fractile with a confidence level of 90 % for the thermal conductivity (${\lambda}90/90$) ranged from 0.00726-0.00814 (W/m K) for silica core VIP. Significant differences between manufacturer-provided data and measurements of thermal conductivity and internal pressure were observed.