• Korean Journal of Environmental Agriculture
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• v.21 no.1
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• pp.24-30
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• 2002

Ginseng (Panax ginseng C. A. Meyer) has been cultivated on raised beds with shading condition for 4 to 6 years because of its physiological characteristics. This shading condition maintains relatively stable soil environments protecting from rainfall and direct sunlight. Therefore, pesticides in ginseng growing soil are exposed to far different environment from the general cropping field. To study the behavior of pesticides under this condition, the effect of covering on the persistency of Procymidone in ginseng cultivating soil was investigated by using several shade materials. The most important factor affecting Procymidone persistency in soil under covering was water leakage rates of shade materials.

• Restorative Dentistry and Endodontics
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• v.24 no.2
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• pp.346-355
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• 1999

To evaluate the micro leakage of compomer, 4 materials were divided into 4 groups of 15 cavities each.(Group 1: Z-100, Group 2: Dyarct AP, Group 3: Fuji II LC, Group 4: Compoglass) After the class II cavities were prepared using carbide bur No. 553, all specimen were restored by incremental filling technique. In group 3, Z-100 was filled with a base of a light curing glass-ionomer. After 7 days, all specimens were thermocycled between $5^{\circ}C$ and $55^{\circ}C$ for 500 cycles, followed by placement in 50% silver nitrate dye for 2 hours at $37^{\circ}C$. After rinsed in distilled water, these teeth were immersed in photodeveloping solution and exposed to fluorescent light for 6 hours. Teeth were then washed in distilled water to remove the photodeveloping solution, sectioned mesio-distally and evaluated. The results were as follows : 1. In the cervical portion, there was significant difference between Fuji II LC and other groups(Z-100, Dyract AP, Compoglass), Fuji II LC had the least value.(p<0.05) 2. In the cervical portion, there was not significant difference among Dyract AP, Z-100 and Compoglass. 3. In the occlusal portion, there was not significant difference among Dyract AP, Z-100 and Compoglass. From the results above, In enamel, microleakage of compomer such as Dyract AP and Compoglass resemble to that of composite resin. It is thought that it is due to characteristics of composite resin portion of compomer. But in dentin, microleakage of compomer is higher than that of resin modified glass ionomer cement, it is thought that in compomer, acid-base reaction is not developed with dentin.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.1
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• pp.89-98
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• 2002

Optical current sensor and optical voltage sensor modules were designed and fabricated to improve measurement error and insulation in automatic power distributor By using Faraday effect, optical current sensor with an $\alpha$-iron core was designed and fabricated to minimize current induction of the other phase and was optimized to maintain linearity. Optical voltage sensor was fabricated owing to the pockets effect and adopted spatial electric field type because of small room in an automatic power distributor. To connect a distributor with an external terminal for signal processing, optical multi connector was designed, fabricated and tested for coupling loss and gas leakage. The linearity of optical current sensor for applied current maintains variation of smaller than 2.5% for applied current range from 20A to 700A. The linearity of optical voltage sensor was smaller than 1% for appling voltage from 6.6kV to 19.8kV. Since the measured characteristics are good, these devices can be considered as being applicable in practice.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.5
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• pp.405-412
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• 2004

In this paper, Non-contact power supply(NCPS) with the long primary cable longer than 20m and the large air-gap between the primary and secondary of Non-Contacting Transformer(NCT) is presented. The NCT has a large leakage inductance bigger than its magnetizing inductance because it has low coupling, and it is not efficient for NCPS to transfer the primary energy to the secondary one. In order to improve this problem, the voltage-gain characteristics of the series resonant converter, the parallel resonant converter, and the series-parallel resonant converter are analyzed respectively. In addition, the experimental results of 10kW prototype the series-parallel resonant converter is presented.

• Restorative Dentistry and Endodontics
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• v.26 no.6
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• pp.464-484
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• 2001

When restoring a tooth, the dentist tries to choose the ideal material for existing situation. One criterion that is considered is its suitability for restoring coronal strength. As more tooth structure is removed, the cusps are weakened and susceptible to fracture. Further, this increased deformation may cause the formation of intermittent gaps at the margin between the hard tissue and the restoration, facilitating marginal leakage. The improvements in ceramic materials now make it possible for alternatives to amalgams, composites, and cast metal to be of offered for posterior teeth. Of the materials used, ceramics most closely approximates the properties of enamel. The introduction of computer-aided design/computer-aided manufacture(CAD/CAM) systems to restorative dentistry represents a major technological breakthrough. It is possible to design and fabricate ceramic restorations at a single appointment. Additionally, CAD/CAM systems eliminate certain errors and inaccuracies that are inherent to the indirect method and provide an esthetic restoration. The aim of this investigation was to study the loading characteristics of CAD/CAM ceramic inlay and to compare the stress distribution and displacement associated with different designs of cavity(the isthmus width and cavity depth). A human maxillary left first premolar was prepared with standard mesio-occlusal cavity preparation, as recommended by the manufacturer Ceramic inlay was fabricated with CEREC 2 CAD/CIM equipment and cemented into the prepared cavity. Three dimensional model was made by the serial photographic method. The cavity width was varied $\frac{1}{3}$, $\frac{1}{2}$ and $\frac{2}{3}$ of intercuspal distance between buccal and lingual cusp tip. The cavity depth was varied 1.5mm and 2.3mm. So six models were constructed to simulate six conditions. A point load of 500N was applied vertically onto the first node of the lingual slope from the buccal cusp tip. The stress distribution and displacement were solved using ANSYS finite element program(Swanson Analysis System). (omitted)

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.6
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• pp.445-449
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• 2020

Non-volatile memory is approaching its fundamental limits with the Si₃N₄ storage layer, necessitating the use of alternative materials to achieve a higher programming/erasing speed, larger storage window, and better data retention at lower operating voltage. This limitation has restricted the development of the charge-trap memory, but can be addressed by using high-k dielectrics. The paper reviews the doping of nitrogen, titanium, and yttrium on high-k dielectrics as a storage layer by comparing MONOS devices with different storage layers. The results show that nitrogen doping increases the storage window of the Gd₂O₃ storage layer and improves its charge retention. Titanium doping can increase the charge capture rate of HfO₂ storage layer. Yttrium doping increases the storage window of the BaTiO₃ storage layer and improves its fatigue characteristics. Parameters such as the dielectric constant, leakage current, and speed of the memory device can be controlled by maintaining a suitable amount of external impurities in the device.

• Journal of Korean Vacuum Science & Technology
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• v.4 no.3
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• pp.73-77
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• 2000

Single crystal and polycrystalline Si thin films were doped with phosphorus by a 2-zone diffusion method to develop the low-resistivity polycrystalline Si electrode for a hemispherical grain. Solid phosphorus source was used in order to achieve uniformly and highly doped surface region of polycrystalline Si films having rough surface morphology. In case of 2-zone diffusion method, it is proved that the heavy doping near the surface area can be achieved even at a relatively low temperature. SIMS analysis revealed that phosphorus doping concentration in case of using solid P as a doping source was about 50 times as that of phosphine source at 750$^{\circ}C$. Also, ASR analysis revealed that the carrier concentration was about 50 times as that of phosphine. In order to evaluate the electrical characteristics of doped polycrystalline Si films for semiconductor devices, MOS capacitors were fabricated to measure capacitance of polycrystalline Si films. In ${\pm}$2 V measuring condition, Si films, doped with solid source, have 8% higher $C_{min}$ than that of unadditional doped Si films and 3% higher $C_{min}$ than that of Si films doped with $PH_3$ source. The leakage current of these films was a few fA/${\mu}m^2$. As a result, a 2-zone diffusion method is suggested as an effective method to achieve highly doped polycrystalline Si films even at low temperature.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.257-257
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• 2010

One of the critical issues for applications of flexible organic thin film transistors (OTFTs) for flexible electronic systems is the electrical stabilities of the OTFT devices, including variation of the current on/off ratio ($I_{on}/I_{off}$), leakage current, threshold voltage, and hysteresis, under repetitive mechanical deformation. In particular, repetitive mechanical deformation accelerates the degradation of device performance at the ambient environment. In this work, electrical stabilities of the pentacene organic thin film transistors (OTFTs) employing multi-stack hybrid encapsulation layers were investigated under mechanical cyclic bending. Flexible bottom-gated pentacene-based OTFTs fabricated on flexible polyimide substrate with poly-4-vinyl phenol (PVP) dielectric as a gate dielectric were encapsulated by the plasma-deposited organic layer and atomic layer deposited inorganic layer. For cyclic bending experiment of flexible OTFTs, the devices were cyclically bent up to $10^5$ times with 5mm bending radius. In the most of the devices after $10^5$ times of bending cycles, the off-current of the OTFT with no encapsulation layers was quickly increased due to increases in the conductivity of the pentacene caused by doping effects from $O_2$ and $H_2O$ in the atmosphere, which leads to decrease in the $I_{on}/I_{off}$ and increase in the hysteresis. With encapsulation layers, however, the electrical stabilities of the OTFTs were improved significantly. In particular, the OTFTs with multi-stack hybrid encapsulation layer showed the best electrical stabilities up to the bending cycles of $10^5$ times compared to the devices with single organic encapsulation layer. Changes in electrical properties of cyclically bent OTFTs with encapsulation layers will be discussed in detail.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.5
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• pp.1117-1125
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• 2006

A study is made on the chest pain in the perspective of Hyungsang medicine. The following are the conclusions produced by the examination on the clinical cases of chest pain. Excessive atmospheric influences (wind, rain, cold and summer heat) are the exogenous causes of chest pain. The endogenous causes are diet, dwelling, sexual life and emotions. Persons of bird type are attacked by the chest pain because of emotional depressions. Those of running animal type get sick of chest pain when wood checks earth. Those of turtle type are a afflicted with chest pain due to depression and stagnation of Ki. Those of fish type suffer from chest pain when the ministerial fire of the liver and kidney becomes hyperactive. Chest pain is causes by leakage of Jung for the Jung kwa person, by stagnation of Ki for the Ki kwa person, by flaming fire due to deficiency of Yim for the Shin kwa person and Dy failure of water and fire in complementing each other for the Hyul kwa person. Chest pain often occurs to persons with the following characteristics upward nose, Dig eyes, chapped lips, pronounced foot of nose, red or yellow complexion, frowning face and wrinkles on the nasal radix. Among the six meridian types, chest pain is often found in the persons of Yangmyung and Taeum meridians. Women suffer from chest pain more often than men because breast is a center of life to her.

• Journal of Korean Neurosurgical Society
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• v.56 no.3
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• pp.211-217
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• 2014

Objective : In Korea, early vertebroplasty (EVP) or delayed vertebroplasty (DVP, which is performed at least 2 weeks after diagnosis) were performed for the treatment of acute osteoporotic compression fracture (OCF) of the spine. The present study compared the outcomes of two surgical strategies for the treatment of single-level acute OCF in the thoracolumbar junction (T12-L2). Methods : From 2004 to 2010, 23 patients were allocated to the EVP group (EVPG) and 27 patients to the DVP group (DVPG). Overall mean age was $68.3{\pm}7.9$ and minimum follow-up period was 1.0 year. Retrospective study of clinical and radiological results was conducted. Results : No significant differences in baseline characteristics were observed between the two groups. As expected, mean duration from onset to vertebroplasty and mean duration of hospital stay were significantly longer in the DVPG ($17.1{\pm}2.1$ and $17.5{\pm}4.2$) than in the EVPG ($3.8{\pm}3.3$ and $10.8{\pm}5.1$, p=0.001). Final clinical outcome including visual analogue scale (VAS), Oswestry Disability Index, and Odom's criteria did not differ between the two groups. However, immediate improvement of the VAS after vertebroplasty was greater in the EVPG ($5.1{\pm}1.3$) than in the DVPG ($4.0{\pm}1.0$, p=0.002). The proportion of cement leakage was lower in the EVPG (30.4%) than in the DVPG (59.3%, p=0.039). In addition, semiquantitative grade of cement interdigitation was significantly more favorable in the EVPG than in the DVPG (p=0.003). Final vertebral body collapse and segmental kyphosis did not differ significantly between the two groups. Conclusion : Our findings suggest that EVP achieves a better immediate surgical effect with more favorable cost-effectiveness.