• Journal of Environmental Science International
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• v.26 no.10
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• pp.1147-1153
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• 2017

To maintain a rich biological diversity is important to develop for biomaterial resources such as Korean evergreen broad-leaved tree species, the distribution of which is restricted to the southern part of Korean peninsula. We assessed photosynthetic characteristics of Quercus acuta and Castanopsis sieboldii, the representative evergreen broad-leaved trees in Korea, in order to establish a basis for conservation strategy related to distributional change in evergreen broad-leaved tree species according to climate change. Photosynthetic characteristics were evaluated in the sun and shade leaves of the two species. Sun leaves in both species revealed higher light compensation point and maximum photosynthetic rate compared to the shade leaves. In addition, photosynthetic rate was higher in Q. acuta than C. sieboldii, which was supported by a higher leaf nitrogen content and leaf mass per area. Water use efficiency was also higher in Q. acuta as compared to that in C. sieboldii. Similar photosynthetic rate, however, was shown in photosynthetic response to $CO_2$ concentration in the intercellular space. These results suggest that both species could respond differently to the changing environmental factors including climate change, suggesting the possibility of distributional changes resulting from a differential growth rate.

• KIEAE Journal
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• v.6 no.2
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• pp.3-10
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• 2006

This study assessed the visual performance of luminous environment by the lightshelf. The subject survey method was used and results are presented and analyzed. The lightshelf daylighting system was developed by LAEL at KH University and was applied on the window of a mock-up office. The questionnaire for assessing visual performance contains 9 questions with 7 grade bipolar scales. The experiment was conducted during the bright part of the day from noon to one thirty on June 7, 2006. The questionnaire for assessing visual performance contains 9 questions with 7 grade bipolar scales. During the experiment was carrying out, the work plane illuminance and luminous distribution at surrounding the windows was measured. The semantic differential rating data of experiment were analyzed by t-test and factor analysis using SPSS 12.0 statistics package. The visual performance of the lightshelf was more positive. The factors affecting the visual performance are task performance and visual comfort. The subjects were more comfortable in a room installed with lightshelves on both the task performance and the visual comfort aspect. Therefore, the application of sloped lightshelf daylighting system improves visual performance of luminous environment.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.190-193
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• 2004

Two different diene monomers [dicyclopentadiene (DCPD) and 5-ethylidene-2-norbomene (ENB)] as self­healing agent for polymeric composites were microencapsuled by in-situ polymerization of urea and formaldehyde. The healing agents were investigated by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Exothermic reaction and glass transition temperature from DSC and storage modulus (G') and tan $\delta$ from DMA curves were analyzed for the samples cured for 5 min and 24 h in the presence of different amounts of catalyst. Micorcapsules were successfully formed for both diene monomers. Microcapsules containing the healing agent were manufactured and its thermal properties were characterized by thermo gravimetric analysis (TGA). Optical microscope (OM) and particle size analyzer (PSA) were employed to observe morphology and size distribution of microcapsules, respectively. Comparison of the two self-healing agents and their microcapsules with the two was made in this study.

• Steel and Composite Structures
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• v.33 no.5
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• pp.699-716
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• 2019

In this paper, wave propagations in sigmoid functionally graded (S-FG) plates are studied using new Higher Shear Deformation Theory (HSDT) based on two-dimensional (2D) elasticity theory. The current higher order theory has only four unknowns, which mean that few numbers of unknowns, compared with first shear deformations and others higher shear deformations theories and without needing shear corrector. The material properties of sigmoid functionally graded are assumed to vary through thickness according sigmoid model. The S-FG plates are supposed to be imperfect, which means that they have a porous distribution (even and uneven) through the thickness of these plates. The governing equations of S-FG plates are derived employed Hamilton's principle. Using technique of Navier, differential equations of S-FG in terms displacements are solved. Extensive results are presented to check the efficient of present methods to predict wave dispersion and velocity wave in S-FG plates.

• Korean Journal of Plant Resources
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• v.20 no.6
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• pp.511-517
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• 2007

A stable method for strain distinction using viral RNA 1 structures analyses was developed and compared with the combined RT-PCR and RAPD methods. Seven out of 61 random primers were found to be polymorphic based on RAPD analysis resulting on the differentiation of the 33 BaYMV isolates into four distinct groups according to geographical districts. The first and largest group includes 13 isolate and consists mainly of two-rowed malting barley in Haenam area. The second group had ten collections from inland in west southern. The third group had seven isolates from west southern coastal region, where mainly six-rowed naked barley is cultivated. The last fourth group included three isolates from Gyungnam region in east southern area. Conclusively, RNA 1 analysis proved to be stable and efficient method for strain distinction for Korean BaYMV isolates. Further, results of pathogenicity and RNA 1 structure analyses revealed four groups BaYMV strains and were distributed all over Korea, represented by Naju, Haenam-okcheon, Iksan and Milyang.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.2
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• pp.126-133
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• 2010

Due to the deployment of various wireless networks originating from CDMA, GSM, and WLAN, it became very convenient to exchange information from one place to another. As compared with the traditional environments for one-way information distribution based on fixed radio frequency bands, the convenient wireless network environments will bring about many changes in positioning technologies based on global navigation satellites. Among the many changes to come, the reconfigurable receiver network is one of the most attractive concepts since it can be tailored to a specific application area among networked robots, formation flying, bridge monitoring, and traffic monitoring. As an initial study to develop a reconfigurable receiver network, this paper deals with the design and implementation of the key elements of the reconfigurable receiver netowork; server, broadcaster, and client. In the designed receiver network, a sever receives and decodes measurements from a reference receiver installed at a known location, a broadcaster processes and transfers the messages from servers to clients and manages connections with servers and clients, a client receives the messages from the broadcaster and performs differential positioning. A real-time experiment result is demonstrated to validate the functionalities of each network element.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.1 no.2
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• pp.190-201
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• 1989

This experimental investigation has been conducted to determine the effects of swirling angle and flow patterns on distributions of void fraction, bubble velocity and two-phase pressure drop in a vertical straight tube. Swirling angles of $0^{\circ}$ (non swirling), $30^{\circ}$, and $45^{\circ}$ were tested with air-water two components over a range of superficial air velocities. A transparent lucite tube of 38mm in internal diameter was used for the test section. The void fraction and bubble velocities were measured by means of a optical fiber probe at the upper part of the swirler in the test section. Pressure drops which seem to be closely related with flow patterns and swirling angle were measured by a differential pressure transducer. It is shown that the probability density functions of pressure drop demonstrate peculiar features for both swirling angles and flow patterns, whereas the distributions of void fraction and bubble velocities are parabolic and flat shape in the vicinity of tube center, respectively except bubbly flow in any swirling angle cases, and the void fraction increases with increasing swirling angle around the center of tube.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.1
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• pp.1-7
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• 1998

The near field radiated from the monopole antenna of the cellular phone was calculated by using the modified finite difference time domain algorithm derived from the integral form of Maxwell's equations. Substituting the near field value into the differential form of Maxwell's equations, SAR's distribution in the human head was obtained. The human head was simulated by a model of 800,000 block cells with dielectric constant and conductivity. The cell size was taken to be 0.5 cm. the transmitted power of the cellular phone was assumed to be 0.6 watts at the frequency of 833 MHz. The distance between the head and the cellular phone was 2.0 cm, the maximum SAR induced in the human head was about 1.5 W/kg and was below the IEEE's upper safety limit of 1.6 W/kg.

• Journal of the Korean Institute of Rural Architecture
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• v.14 no.2
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• pp.67-74
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• 2012

This study investigated that grasped the present state of high-rise apartment on Urban Street color, through the color image estimation effect of primary factor on color image preference. The range of study were high-rise apartment on Urban Street color of land for housing, Sangmu, Woonnam, Shinchang, Pungam, Ilgok, Moonheung district. The method of study put out a model of reference after photography a spot colorimeter BIB test. And the data analyzing was factor analysis, multi regression through Semantic Differential Method, questionnaire. The result of study, the present state of color was used predominate, support color is YR, Y, and stress color is YR, R. Predominate color showed distribution of high luminosity, low freshness and assistance, stress color is middle luminosity, low freshness. And effects of primary factor on color image preference were 'unification', 'comfortableness', 'sophistication'. The result of this study showed that need high luminosity color for comfortableness to improve of high-rise apartment on Urban Street color, harmony of color, harmony of vertical horizontality color scheme pattern, consult square rate of stress color.

• Journal of Powder Materials
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• v.7 no.3
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• pp.143-148
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• 2000

NiAl alloy powders were prepared by mechanical alloying method and bulk specimens were produced using hot isostatic pressing techniques. This study focused on the transformation behavior and properties of Ni-Al mechanically alloyed powders and bulk alloys. Transformation behavior was investigated by differential scanning calorimeter (DSC), XRD and TEM. Particle size distribution and microstructures of mechanically alloyed powders were studied by particle size analyzer and scanning electron microscope (SEM). After 10 hours milling, XRB peak broadening appeared at the alloyed powders with compositions of Ni-36at%Al to 40at%Al. The NiAl and $Ni_3Al$ intermetallic compounds were formed after water quenching of solution treated powders and bulk samples at $1200^{\circ}C$, but the martensite phase was observed after liquid nitrogen quenching of solution treated powders. However, the formation of $Ni_3Al$ intermetallic compounds were not restricted by fast quenching into liquid nitrogen. It is considered to be caused by fast diffusion of atoms for the formation of stable $\beta$(NiAl) phase and $Ni_3Al$ due to nano sized grains during quenching. Amounts of martensite phase increased as the composition of aluminium component decreased in the Ni-Al alloy, which resulted in the increasing damping properties.