• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.2
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• pp.67-72
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• 2005

Overwintering capacity, closely related to winter hardiness, of Chinese milk vetch planted with different sowing times and sowing practices was investigated to improve the incorporation into cropping system in Korea. The tolerance to low temperature was evaluated with $LT_50$ using leaf disc leaching method. Dry weight of CMV was reduced remarkably with delayed planting from Sep. 5 to Oct. 20. The differences in tolerance to freezing temperature were not conspicuous among CMV genotypes, however, the differences between genotype (collections at different regions) were due to the plant architecture, mainly to the leaf angle. The crouching genotype collected at central region of Korean peninsula, which showed excellent freezing tolerant, has planophile leaves. The feature of internal constituents of CMV genotypes did not show any noticeable differences with respect to the freezing tolerance which evaluated by leaf disc leaching experiment. To overcome the poor overwintering capacity, tolerant genotype should be developed by selection with considering the plant architecture. The reduction of CMV growth during overwintering period was ameliorated with furrow-sowing under late-sown condition, therefore, when the CMV is inevitably sown late after recommended time, the seeds should be sown on furrow to overcome the cold stress.

• Textile Coloration and Finishing
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• v.7 no.2
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• pp.24-31
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• 1995

The properties of carbon fibers made from PAN are controlled by the heat treatment conditions. The length changes of high strength homo-PAN and co-PAN (acrylonitrile/acrylamide= 98/2wt% ) fibers under constant tensile stress during heat treatment in nitrogen gas were investigated by measuring the shrinkage behavior. In order to elucidate the relation between the length and fine structure change, the measurements of the crystalline orientation and birefringence index etc. were made for the fibers treated under linear heating up to 27$0^{\circ}C$. There are two regions in the length change with heat treatment temperature. The change in the initial period is mainaly due to the relaxation of amorphous molecular chain confined by the fiber-manufacture process. The length change in later period is considered to arise as cyclization reactions. The co-PAN fibers caused a larger shrinkage, while the onset of the shrinkage change in later period is, shifted to lower temperature. Significant morphological changes are shown to precede onset of the cyclization reactions and also during these reactions.

• Fashion & Textile Research Journal
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• v.7 no.1
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• pp.96-100
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• 2005

The bleaching is one of the worst factors which leads to the damage of the human hair. The cuticle of the human hair is injured by the alkali that is one of the chief ingredients of a bleaching agent. The alkali component of the bleaching solution chemically reacts with human hair, reducing the tenacity and dissolving the cuticle layer. The purpose of this study is to examine the effects of bleaching time and temperature on the physical properties and morphology. The results were as follows. 1. The stress-strain curves for human hair indicated the three distinct regions, such as Hookean region, Yield region and post-Yield region. The tenacity of hair is reduced gradually with an increase of bleaching time. Under these same conditions, elongation of the hair increased. 2. The greatest drop in tenacity for hair occured between $40^{\circ}C$ and $60^{\circ}C$ of bleaching temperature. 3. Compared with the virgin hair, bleached hair showed a slower rate of weight reduction in the TGA thermogram. The rate decreased gradually as the bleaching time and temperature increased. 4. As the bleaching conditions reached time and temperature extremes, the human hair cuticle became more damaged. The cuticle layers seemed to have dissolved, as seen in the SEM photographs.

• Plant Biotechnology Reports
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• v.3 no.2
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• pp.127-134
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• 2009

Members of the NAM-ATAF-CUC (NAC) protein family are plant-specific transcription factors that contain a highly conserved N-terminal NAC-domain and diverse C-terminal regions. They have been implicated in plant development and abiotic stress responses. To identify interacters of rice NAC-domain proteins (OsNACs), we performed yeast two-hybrid screening of rice cDNA library using OsNAC5 as a bait, and the results showed that OsNAC5 interacts with other OsNACs including itself. To delineate an interacting domain, a series of deletion constructs of four OsNACs were made and transformed into yeast in various combinations. The results revealed that the conserved NAC domain of OsNACs plays a primary role in homodimer and heterodimer formation, and a part of C-terminal sequence is also necessary for the interaction. In vitro pull-down assays using recombinant OsNAC proteins verified the dimer formations, together suggesting that OsNACs may act by forming homodimers and/or heterodimers in plants.

• Journal of Soil and Groundwater Environment
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• v.15 no.6
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• pp.1-8
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• 2010

The groundwater level distribution and characteristics of responses to rainfall were examined in the Haean basin of Yangu that has a single stream exit to the east. The groundwater levels showed a circular or elliptical distribution converging the center of the basin with different hydraulic gradients in the north and south regions. The waterlevel elevations exhibited a perfect correlation with topographic elevation ($r^2=0.99$) while the depth to water showed a rather weak correlation ($r^2=0.49$). The water table fluctuation (WTF) method yielded recharge ratios of 6.1~12.65% ($S_y=0.02$) and 15.2~28.5% ($S_y=0.05$). The waterlevels of HG3 well, which is much proximal to a stream, were weakly auto-correlated but they were highly sensitive to direct infiltration from the rainfall event. The shorter regulation times of the HG3 represented a quicker dissipation of the input stress (rainfall).

• International Journal of Fluid Machinery and Systems
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• v.5 no.4
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• pp.168-173
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• 2012

This paper presents a numerical investigation on the aerodynamic performance according to the application of splitter blades in an impeller of a centrifugal fan used for a refuse collection system. Numerical analysis of a centrifugal fan was carried out by solving three-dimensional Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model. A validation of numerical results was conducted by comparison with experimental data for the pressure and efficiency. From analyses of the internal flow field of the reference fan, the losses by the reverse-flows were observed in the region of the blade passage. In order to reduce these losses and enhance fan performance, two splitter blades were applied evenly between the main blades, and centrifugal impellers having the different numbers of the main blades were tested with their application. Throughout the numerical analyses of the centrifugal fan with splitter blades, it was found that the reverse-flow regions in the blade passage can be reduced by controlling the main blade numbers with splitter blades. The application of splitter blades in a centrifugal fan leads to significant improvement in the overall fan performance.

• International Journal of Aerospace System Engineering
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• v.2 no.2
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• pp.19-23
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• 2015

This work deals with the study of buckling and post buckling characteristics of laminated composite plates with and without localized regions of damage. The need of a detailed study on Finite Element Analysis of buckling and post buckling of laminated composite structures considering various aspects enhances the interest among researchers. Mathematical formulation is developed for damaged composite plates using a finite element technique based on Inverse Hyperbolic Shear Deformation Theory. This theory satisfies zero transverse shear stresses conditions at the top and bottom surfaces of the plate and provides a non-linear transverse shear stress distribution. Damage modeling is done using an anisotropic damage formulation, which is based on the concept of stiffness change. The structural elements are subjected to in-plane loading. The computer program is developed in MATLAB environment. The numerical results are presented after through validation of developed finite element code. The effect of damage on buckling and post buckling has been carried out for various parameters such as amount of percentage of damaged area, damage intensity, etc. The results show that the presence of internal flaws will significantly affect the buckling characteristics of laminated composite plates. The outcomes and remarks from this work will assist to address some key issues concerning composite structures.

• Journal of the Ergonomics Society of Korea
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• v.28 no.4
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• pp.83-89
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• 2009

This study was conducted to assess exposure to musculoskeletal disorders risk factors in the cooking & housekeeping jobs in hotel work. PATH (posture, activity, tools and handling) method was used for data collection at the 6 hotel settings in different regions across Korea. From 26 workers, a total of 949 PATH observations were obtained. The highest percent time on non-neutral posture was 78% for pinch grip, followed by 74%(wrist deviation), 52%(trunk posture), 37%(shoulder/arm posture), and 30%(neck posture). The highest percent time in the three HAL variables was 47% for HAL-cat2. The percent time of items in relation to both loads with more than 5kg and contact stress was less than 2%. The hotel workers were not exposed to vibration.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.238.2-238.2
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• 2012

We report the results of KVN-VERA('KAVA'; KVN and VERA Arrary) AGN WG test observation in 2011 and 2012. The results from these commisioning years show that 'KAVA' is able to produce noble images of radio loud AGNs at 22 and 43GHz. This dedicated high frequency VLBI facility will be especially competitive for the regions where conventional low freuquency facilities see the optically thick part of synchrotron radiation. In the second part of this talk, we report the early science activities of the AGN WG. Sgr A*, Jet acceleration zone of M87, extremely young radio galaxies are the prime cadidates of the joint activities. Lastly we will stress how the phase-referencing 'KAVA' does enhance the imaging sensitivity and open new era of VLBI AGN researches.

• Structural Engineering and Mechanics
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• v.14 no.1
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• pp.99-118
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• 2002

The scaled-boundary finite element method is a novel semi-analytical technique, combining the advantages of the finite element and the boundary element methods with unique properties of its own. The method works by weakening the governing differential equations in one coordinate direction through the introduction of shape functions, then solving the weakened equations analytically in the other (radial) coordinate direction. These coordinate directions are defined by the geometry of the domain and a scaling centre. This paper presents a general development of the scaled boundary finite-element method for two-dimensional problems where two boundaries of the solution domain are similar. Unlike three-dimensional and axisymmetric problems of the same type, the use of logarithmic solutions of the weakened differential equations is found to be necessary. The accuracy and efficiency of the procedure is demonstrated through two examples. The first of these examples uses the standard finite element method to provide a comparable solution, while the second combines both solution techniques in a single analysis. One significant application of the new technique is the generation of transition super-elements requiring few degrees of freedom that can connect two regions of vastly different levels of discretisation.