• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.193-194
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• 1998

Recently, evaluation of brain transport of taurine which is possible to effect on Alzheimer's disease has investigated in rats. Also, internal carotid artery perfusion (ICAP) method is very useful for measuring of blood-brain barrier (BBB) permeability in rats. But ICAP has difficulties to evaluate of BBB permeability in mice especially. In the present study examines neuropharmaceutials permeability through the BBB in mice by common carotid artery perfusion (CCAP) method that modify ICAP method and require simple surgery. The external carotid artery (ECA) is cannulated with coagulating pterygopalatine artery (PPA) on ICAP method, while CCA is cannulated without coagulating PPA on CCAP method. The CCAP method require 4-5 fold higher infusion rate than ICAP method because an additional factor of 2 must be incorporated to adjust for fluid loss to the extracerebral circulation.

• Wind and Structures
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• v.21 no.3
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• pp.311-329
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• 2015

A method for analyzing the coupled wind-vehicle-bridge system is proposed that also considers the shielding effect of the bridge tower with triangular wind barriers. The static wind load and the buffeting wind load for both the bridge and the vehicle are included. The shielding effects of the bridge tower and the triangular wind barriers are incorporated by taking the surface integral of the wind load. The inter-history iteration is adopted to solve the vehicle-bridge dynamic equations with time-varying external loads. The results show that after installing the triangular wind barriers in the area of the bridge tower, the bridge response and the vehicle safety factors change slightly. The peak value of the train car body acceleration is significantly reduced when the wind barrier size is increased.

• Journal of Drive and Control
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• v.14 no.4
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• pp.61-70
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• 2017

In this study, an extended-state-observer (ESO) based non-linear servo control is introduced for an electro-hydrostatic actuator (EHA). Almost hydraulic systems not only are highly non-linear system that has mismatched uncertainties and external disturbances, but also can not measure some states. ESO that only use an output signal can be used to compensate these uncertainties and estimate unmeasurable states. To improve the position tracking performance, the barrier Lyapunov function (BLF) that can guarantee an output tolerance is introduced for the position tracking error signal of back stepping control procedures. Finally, the proposed servo control is compared with the proportional-integral (PI) control.

• Journal of the Korean Magnetics Society
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• v.16 no.2
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• pp.130-135
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• 2006

We theoretically demonstrate that the interlayer exchange coupling (IEC) energy can be manipulated by means of an external bias voltage in a $F_1/NM/F_2/S$$(F_1:ferromagnetic,\;NM:nonmagnetic\;metallic,\;F_2:ferromagnetic,\;S:semiconductor\;layers)$ four-layer system. It is well known that the IEC energy between two ferromagnetic layers separated by nanometer thick nonmagnetic layer depends on the spin-dependence of reflectivity to the $F_1/NM/F_2/S$ four-layer system, where the reflectivities at the interface in $NM/F_2$ interface also depends on $F_2/S$ interface due to the multiple reflection of an electron-like optics. Finally, the IEC energy depends on the spin-dependent electron reflectivity not only at the interfaces of $F_1/NM/F_2$, but also at the interface of $F_2/S$. Naturally the Schottky barrier is formed at the interface between metallic ferromagnetic layer and semiconductor, the Schottky barrier height and thickness can be tailored by an external bias voltage, which causes the change of the spin-dependent reflectivity at $F_2/S$ interface. We show that the IEC energy between two ferromagnetic layers can be controlled by an external bias voltage due ti the electron-optics nature using a simple free-electron-like one-dimensional model.

• 전기의세계
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• v.26 no.4
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• pp.68-72
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• 1977

The main purpose of this paper is to study on the nature of the traps in polymer. The polyethlene is typical of polymer material as to be selected for a sample. The current I$_{th}$ are obtained with an small external bias voltage from high density polyethylene which have been treated by the high-field application. Two peaks, P$_{1}$ and P$_{2}$ with maxima near 85.deg. C, respectively, appeared on the current I$_{th}$ spectrum. From the results of experiment, It is clear that The current I$_{th}$ arises from the drift, under the external field, of carriers released from the trap sites by the heating and the trap is surrounded by a potential barrier and trapping proceeds during the high-field treatment. The obtained results can suggest that polyethylene contains trap sites which have an important role in the electrical conduction and breakdown of polymeric materials.rials.

• Transactions on Electrical and Electronic Materials
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• v.17 no.1
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• pp.37-40
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• 2016

Performance enhancement of organic light-emitting diodes (OLEDs) is investigated in a device structure of ITO/TPD/Alq₃/LiF/Al and ITO/TPD/Alq₃/BCP/LiF/Al. Here, bathocuproine (BCP) is used as an electron-transport layer. Current density-voltage-luminance characteristics of the OLEDs show that the performance of the device is better with BCP layer than without BCP layer. The current density, luminance, luminous efficiency, and external-quantum efficiency are improved by approximately 22%, 50%, 2%, and 18%, respectively. Since the BCP layer lowers the electron energy barrier, electron transport is facilitated and the movement of hole is blocked as the applied voltage increases. This results in an increased recombination rate of holes and electrons.

• Journal of Korea Port Economic Association
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• v.28 no.1
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• pp.203-227
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• 2012

Based on the review of the existing studies, this study built the conceptual framework describing the structural relationships among port service quality dimensions(port internal service quality, external service quality, interaction quality), customer satisfaction, customer trust and customer loyalty. In specific, switching barrier was included as moderator in customer satisfaction and customer loyalty relationships. The subjects are the customers who use the Busan New Port. A survey using 317 customers was conducted, Confirmatory factor analysis was conducted to test the validity of the measurement model, and AMOS analysis approach was used to gain important insights into how customer retention in the port business can be ensured. Results in this paper indicate that customer trust and satisfaction are identified as antecedents of the port service quality dimensions. Customer satisfaction positively influences trust. Customer trust and satisfaction positively influence loyalty. Switching barrier positively moderates the relationship of customer satisfaction and customer loyalty. Finally, this study suggests that the implications of these findings and offers directions for future research.

• Journal of the Korean Institute of Rural Architecture
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• v.25 no.4
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• pp.37-44
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• 2023

As a basic study to analyze the relative importance of external space in urban development projects, this study selects evaluation indicators for external space planning and then analyzes systematic external space planning through expert surveys. The scope of the study is to examine the criteria of evaluation items for external space derived from existing studies and to suggest the importance and priority of evaluation items. As a research method, we reviewed the legal and research literature on landscape planning and external space-related guidelines, and conducted a primary review of external space planning evaluation items analyzed by questionnaire. The reviewed items were again reviewed and selected through expert group discussions (FGI). The selected evaluation items were surveyed by expert groups and analyzed in depth using the hierarchical analysis method (AHP). Looking at the relative importance of the calculated sub-items, among the 17 sub-items, 'planning open space' (.096) is the largest, followed by 'pedestrianization' (.082), 'linking with adjacent buildings, streets, parks, and green areas' (.077), 'securing public space through various planning techniques such as linking with pedestrian paths' (.066), 'Plan the placement, form, and scale of buildings in consideration of the identity of the destination' (.065), 'Plan buildings, streets, parks, and green spaces in an integrated and holistic manner' (.065), 'Harmonize with the surrounding environment (landscape)' (.063), 'Harmonize with surrounding buildings and apply landscape planning in urban planning' (.063), 'Entrances and lower floors of buildings are planned as parks for users and pedestrians' (.060), 'Preserve and expand green areas and establish maintenance plans for urban greening' (.054), 'Form the basis for a comfortable life for urban residents by providing long-term development directions' (.047), 'Activate community activities and plan pedestrian environments and streetscapes considering human scale' (.047), 'Establish and propose basic directions for urban greening' (.046), 'Plan buildings, streets, parks, and green areas considering the hierarchy and characteristics of the landscape structure' (.045), 'Plan for integrated land use' (.045), 'Create green axes in connection without cutting them due to development activities' (.044), and 'Apply barrier free design' (.034).

• YAKHAK HOEJI
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• v.42 no.2
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• pp.196-204
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• 1998

The blood-brain barrier (BBB) of rats was modificated opening reversibly by infusing a hyperosmotic solution of arabinose (1.6 molal) into the right external carotid artery. Pre vious studies demonstrated that permeability was increased maxmmally in the first 15 min and remained slightly elevated at 1 hr. As control reference, saline was used. In the present study, to evaluate the effects of osmotic BBB opening on the BBB trasport according to hydrophilic or hydrophobic characteristics of drugs. And the differences of the uptakes of these compounds to right (treated osmotic opening) and left (untreated) hemispheres in same rats were compared each other following injection of 8 mCi per rat of $^{99m}Tc$-ethylene triamine pentaacetic acid (DTPA) as hydrophilic drug or 5mg/kg of phenytoin as hydrophobic drug mto the right external carotid artery of rats between two groups (1.6 molal arabinose vs saline). The uptakes of $^{99m}Tc$-DTPA and phenytoin in the right cerebral hemispheres were increased to about thirty three times and twice rather than those in the left cerebral heimspheres, respectively. And PAs (permeability X capillary surface area) were also increased from a control mean of 2.11${\times}10^{-4}$ (Untreated) to 6.98${\times}10^{-3}\;sec^{-1}$ (treated osmotic opening for $^{99m}Tc$-DTPA and 0.29 to 0.17 $sec^{-1}$ for phenytoin, respectively. From the results of present study, it is noted that osmotic opening of BBB is more effective in the brain delivery of hydrophilic drugs rather than that of hydrophobic drugs.

• The Journal of Sustainable Design and Educational Environment Research
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• v.18 no.3
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• pp.16-27
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• 2019

Based on basic studies on the current status index of BF certification application for school facilities according to the BF certification implementation, this study sought to improve the direction of the different BF certification evaluation indexes for school facilities by investigating and analyzing the status of BF Reservation Certification for elementary schools. A comparative analysis of the status and evaluation indexes of 30 elementary schools in the Gyeongsang region that included indicators of external and internal facilities, sanitary facilities, guidance facilities, and other facilities indicated that school facilities are insufficient to discriminate based on criteria and thus need to be updated for accurate grading. For school facilities that are open for anyone to use, quality improvement should be induced by improving standards and adjusting points for items that earn middle and lower grades.