• Journal of Korean Neurosurgical Society
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• v.46 no.4
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• pp.317-321
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• 2009

Objective : In the thoracic spine, insertion of a pedicle screw is annoying due to small pedicle size and wide morphological variation between different levels of the spine and between individuals. The aim of our study was to analyze radiologic parameters of the pedicle morphometry from T1 to T8 using computed tomographic myelography (CTM) in Korean population. Methods : For evaluation of the thoracic pedicle morphometry, the authors prospectively analyzed a consecutive series of 26 patients with stable thoracic spines. With the consent of patients, thoracic CTM were performed, from T1 to T8. We calculated the transverse outer diameters and the transverse angles of the pedicle, distance from the cord to the inner cortical wall of the pedicle, and distance from the cord to the dura. Results : Transverse outer pedicle diameter was widest at T1 ($7.66{\pm}2.14\;mm$) and narrowest at T4 ($4.38{\pm}1.55\;mm$). Transverse pedicle angle was widest at T1 ($30.2{\pm}12.0^{\circ}$ and it became less than $9.0^{\circ}$ below T6 level. Theoretical safety zone of the medial perforation of the pedicle screw, namely, distance from the cord to inner cortical wall of the pedicle was more than 4.5 mm. Conclusion : Based on this study, we suggest that the current pedicle screw system is not always suitable for Korean patients. Computed tomography is required before performing a transpedicular screw fixation at the thoracic levels.

• Journal of the Korean Society of Costume
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• v.61 no.6
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• pp.131-145
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• 2011

The purpose of this study is to provide preliminary data on strategies to create a domestic prestige brand based on Korean traditional designs. This study also deals with how to promote this brand around the world. The two points mentioned above will be accomplished by examining the characteristics of the brand '3.1 Phillip Lim' which succeeded in both design and marketing during a short period of time. The method of the study will be followed. Firstly, the basic design and philosophical background of Phillip Lim was investigated, after reviewing the global luxury market and current status of overseas expansion of Korean designers through paper study and antecedent workups. Secondly, for the practical stage, design characteristics and marketing strategies were reviewed with the collections of '3.1 Phillip Lim'. Three factors found in '3.1 Phillip Lim's design success are as follows: First, practical and simple designs using fabrics of high quality. Second, handcraft elements and interesting details that differentiates his design identity. Third, femininity expressed in the feminine silhouette and color. The marketing elements that made '3.1 Phillip Lim' as a successful brand are: First, differentiated positioning as a luxurious contemporary brand. Second, brand promotion through various collaborations. Third, the gradual expansion of women's, men's, kids' apparel to accessory, lingerie and the stable flagship stores. Thus, '3.1 Phillip Lim' has combined modern and classic styles using high quality fabrics and practical designs with unique details. Through it's differentiated marketing strategy targeting New York's market, which prefers popular 'luxury contemporary brand's rather than high-end luxury brands, this brand's creativity and commercial aspects contributed to make '3.1 Phillip Lim' into a luxury brand that represents New York fashion. Korean designers who seek to enter the global fashion industry should consider applying Korean traditional designs on global designs to make favorable products and localize these products according to regional characteristics.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.490.1-490.1
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• 2014

The ZnO nanowire (NW)-based nanogenerators (NGs) can have rectifying current and potential generated by the coupled piezoelectric and semiconducting properties of ZnO by variety of external stimulation such as pushing, bending and stretching. So, ZnO NGs needed to enhance durability for stable properties of NGs. The durability of the metal electrodes used in the typical ZnO nanogenerators(NGs) is unstable for both electrical and mechanical stability. Indium tin oxide (ITO) is used as transparent flexible electrode but because of high cost and limited supply of indium, the fragility and lack of flexibility of ITO layers, alternatives are being sought. It is expected that carbon nanotube and Ag nanowire conductive coatings could be a prospective replacement. In this work, we demonstrated transparent flexible ZnO NGs by using CNT/Ag nanowire hybrid electrode, in which electrical and mechanical stability of top electrode has been improved. We grew vertical type ZnO NW by hydrothermal method and ZnO NW was coated with hybrid silicone coating solution as capping layer to enhance adhesion and durability of ZNW. We coated the CNT/Ag nanowire hybrid electrode by using bar coating system on a capping layer. Power generation of the ZnO NG is measured by using a picoammeter, a oscilloscope and confirmed surface condition with FE-SEM. As a results, the NGs using the CNT/Ag NW hybrid electrode show 75% transparency at wavelength 550 nm and small change of the resistance of the electrode after bending test. It will be discussed the effect of the improved flexibility of top electrode on power generation enhancement of ZnO NGs.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.241.1-241.1
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• 2014

The large-area high-power radio-frequency (RF) driven ion sources based on the negative hydrogen (deuterium) ion beam extraction are the major components of neutral beam injection (NBI) systems in future large-scale fusion devices such as an ITER and DEMO. Positive hydrogen (deuterium) RF ion sources were the major components of the second NBI system on ASDEX-U tokamak. A test large-area high-power RF ion source (LAHP-RaFIS) has been developed for steady-state operation at the Korea Atomic Energy Research Institute (KAERI) to extract the positive ions, which can be used for the NBI heating and current drive systems in the present fusion devices, and to extract the negative ions for negative ion-based plasma heating and for future fusion devices such as a Fusion Neutron Source and Korea-DEMO. The test RF ion source consists of a driver region, including a helical antenna and a discharge chamber, and an expansion region. RF power can be transferred at up to 10 kW with a fixed frequency of 2 MHz through an optimized RF matching system. An actively water-cooled Faraday shield is located inside the driver region of the ion source for the stable and steady-state operations of RF discharge. The characteristics and uniformities of the plasma parameter in the RF ion source were measured at the lowest area of the expansion bucket using two RF-compensated electrostatic probes along the direction of the short- and long-dimensions of the expansion region. The plasma parameters in the expansion region were characterized by the variation of loaded RF power (voltage) and filling gas pressure.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.23-26
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• 2012

In MANET, the nodes, configuring a path, act as routers and they have various mobilities. If the path is broken by a node's moving, a new path has to be found again. For this reason, the node with high mobility should be excluded from configuring a path as far as possible. In this paper, we propose an algorithm which excludes nodes with high mobility from constructing a path by collecting and managing the information of mobility. As the result, the proposed algorithm provides more stable paths. In this algorithm, we appends MRecord Field and Relieve Field in the routing table to collect and manage the mobility information by extending current AOMDV. In addition, we add Mbl Field to RREP (Route Reply) message to adapt the collected information to configure the real path.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.5
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• pp.472-481
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• 2002

In this paper, the instantaneous flux Is applied to control the position of the SRG (Switched Reluctance Generator) without position sensor. The position information of the rotor is required in the drive of SRG. These data are generally obtained by a shaft encoder or resolver. In some cases, the EMI(Electro Magnetic Interference), vibration, thermal, and humidity environments may cause the difficulties in maintaining the satisfactory performance for the position detection. Therefore, the elimination of the position and speed sensor is needed. In this paper, a new method for the position estimation of the SRG is proposed. The estimation of the flux is calculated by using the measured voltage and current. The rotor position gets from the flux profile. The output voltage is also controlled constantly by PR control algorithm. These methods are verified by computer simulations md experiments using DSP. Experimental results certificate that the proposed method is able to control the SRG stable, and keep the output voltage constant in spite of changing of the load.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.1
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• pp.17-24
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• 2004

The starter of the turbo generator is composed of a high speed generator(HSG), an inverter and a boost converter instead of a gearbox, a DC motor and a low-voltage battery in the starter of the turbo shaft generation system. Because turbo generator is needed a high speed motoring at start-up, high speed generator has a low leakage inductance and inverter need a high DC link voltage. In this study, for developing the stater of a turbo generator, a boost converter with a high capacity was developed to convert high voltage from a low battery voltage. And for controlling a high frequency current to be injected to a motor winding with a low leakage inductance, the inverter with a high precision and a high speed operation was designed and for a stable ignition, the starting algorithm of a turbo generator was proposed. Turbo generator was started by the starter developed to verify the performances.

• Journal of the Korea Institute of Building Construction
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• v.17 no.5
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• pp.429-435
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• 2017

The aim of the research is, for normal strength range concrete mixture, to evaluate the fluidity development and robustness of the mixture depending on various water reducers. Although a usage of water reducer has been essential to make a concrete under the current conditions of worsen aggregate quality, selection of appropriate performance of water reducer is significant. Hence, in this research, regarding the normal strength range mortar, three different performance of water reducers were evaluated in aspects of securing fluidity, and robustness, rheological behaviors. Additionally, for the concrete mixture, the fluidity change was evaluated depending on unit water content for each different water reducer, and the water reducing performance with manufacturing cost was compared and analyzed. By the result of this research, it is expected to provide a case of determining appropriate kind of water reducer and to contribute on conditions of securing sufficient fluidity with stable quality and economical advantage.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.54-57
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• 2003

[ $HfO_xN_y$ ] films using a hafnium tertiary-butoxide $(Hf[OC(CH_3)_3]_4)$ in plasma and $N_2$ ambient were prepared to improve the thermal stability of hafnium-based gate dielectrics. A 10% nitrogen incorporation into $HfO_2$ films showed a smooth surface morphology and a crystallization temperature as high as $200^{\circ}C$ compared with pure $HfO_2$ films. The $TaN/HfO_xN_y/Si$ capacitors showed a stable capacitance-voltage characteristics even at post-metal annealing temperature of $1000^{\circ}C$ in $N_2$ ambient and a constant value of 1.6 nm EOT (equivalent oxide thickness) irrespective of an increase of PDA and PMA temperature. Leakage current densities of $HfO_xN_y$ capacitors annealed at PDA temperature of 800 and $900^{\circ}C$, respectively were approximately one order of magnitude lower than that of $HfO_2$ capacitors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2588-2595
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• 2013

In a traditional hydraulic elevator, elevator car is descended by down control valve, and the oil hydraulic energy must be lost during the descending stroke. In this paper, the performance characteristics of the hybrid type energy saving unit, is used to save the hydraulic energy which is lost during the descending stroke, for a hydraulic elevator are studied. The energy can be reused as the auxiliary power. The results show that the performance characteristics, such as the pressure, flow rate, output current and voltage, efficiency, and the energy recovery rate of the unit are stable and good as the energy recovery rate is 54%, and the energy saving unit is useful to reuse the saved energy during the descending stroke of elevator car. Also, it was confirmed that the energy saving unit can be deployed on a commercial scale.