• Journal of the Korean Wood Science and Technology
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• v.44 no.3
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• pp.295-301
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• 2016

In this study, relationship between seed origin and growth rate of Alnus glutinosa from different seed collection (Yugoslovia, ltaly, United Kingdom, Bulgaria) was investigated with focused on anatomical properties as wood fiber length, vessel element length and diameter. Alnus glutinosa showed diffuse-porous wood with scalariform perforation in alternate pitting. Ray height was 9~11 in tangential section and ray number were 16~26 in cross section. There were no differences on latewood focused on wood fiber length, length and diameter of vessel element, but difference on earlywood. Other than Yugoslavian seed, there was better growth rate with shorter wood fiber and vessel element length on latewood. However, seed from Yugoslovain showed better growth rate with longer wood fiber and vessel element length than other 3 seed orgins.

• Korea journal of population studies
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• v.24 no.1
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• pp.91-121
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• 2001

This paper attempts to investigate the influence of IMF economic crisis on family lives through questionnaire survey of 1001 women in Seoul. According to the results of the survey, we found the following changes that the economic crisis brought to the family lives. With the unemplyment, communication between husbands and wives became more dense in both positive and negative ways. While the possibility of violence and separation beteen husbands and wives was relatively low, violence against the children more directly reflects the economic difficulties . In the economic crisis, relatives are more important resouces for supports than friends and social welfare institutions . Especially the families of the wives are the most important supporters. Through the changes of consumption pattern in economic crisis. we confirmed that the expences for cultural activities, the hospitals and private education have some flexibility. That is, those expences firstly decreased in the economic crisis. Confronting the economic difficulties economic motivation of women to find works became stronger and we saw same possibility of changes of women\`s role pattern by undergoing economic difficulties.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.377-381
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• 2006

This paper describes experimental work to control supersonic jet noise using a mesh screen that is placed at the nozzle exit plane. The mesh screen is a wire-gauze screen that is made of long stainless wires with a very small diameter. The nozzle pressure ratio is varied to obtain the supersonic jets which are operated in a wide range of over-expanded to moderately under-expanded jets. In order to perturb mainly the initial jet shear layer, the hole is perforated in the central part of the mesh screen. The hole size is varied to investigate the noise control effectiveness of the mesh screen. A schlieren optical system is used to visualize the flow fields of supersonic jet with and without the mesh screen device. Acoustic measurement is performed to obtain the OASPL and noise spectra. The results obtained show that the present mesh screen device leads to a substantial suppression of jet screech tones. The hole size is an important factor in reducing the supersonic jet noise. For over-expanded jets, the noise control effectiveness of the mesh screen appears more significant, compared to correctly and under-expanded jets

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.3
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• pp.141-154
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• 1987

The algorithm proposed utilizes the tow-levels technique. In the first level which consists of teeatment only the applied load and design stress as the random variables whose parent distribution has the normal distribution, the cross-sectional areas of the truss members such that the their probabilities of failure have the preseribed failure probabilites are optimized by transforming the nonlinear problem into SUMT, and solving it utilizing modified Newton-Raphson method. In the second level, the geometric shape of truss structure is optimized by utilizing the unidirectional search technique of Powell method which makes it possible to minimize only the objective function. The algorithm proposed is numerically tested for the several truss structures with various shapes and loading conditions. The numerical analysis shows that the rate of decreasing the weight of truss structures is dependent on the prescribed failure probability of the each member of truss structure and the covariance of the applied load and design stress.

• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.76-83
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• 1997

Blends of thermotropic liquid crystalline polymer(TLCP) with poly(ethylene terephthalate) (PET) were prepared by the coprecipitation from a common solvent. The blends were processed through a capillary die at $287^{\circ}C$ to produce a monofilament. Morphology and mechanical, thermal properties of blends and composites were examined by differential scanning calorimetry(DSC), tensile test, optical microscopy and scanning electron microscopy. Crystallization kinetics of the blends were investigated by the isothermal DSC method. The Avrami analyses were applied to obtain the information on the crystal growth geometry and factors controlling the rate of crystallization. In the blends, liquid crystalline phase did not reveal any significant macrophase separation and thermal degradation at the processing temperature. From scanning electron micrographs of cryogenic fracture surfaces of extruded fibers, the TLCP domains were found to be more or less finely dispersed with $0.1{\mu}m$ to $0.2{\mu}m$ in size. Interfacial adhesion between the TLCP and matrix polymer was excellent. Tensile strength and modulus of TLCP/PET in-situ fiber composites were enhanced with increasing draw ratio and LCP content.

• Food Science of Animal Resources
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• v.31 no.4
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• pp.603-608
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• 2011

The objective of this study was to investigate factors related to carcass traits of Hanwoo. In the statistical model developed in this study, slaughterhouse, carcass year, carcass month and sex effects were used as fixed effects and carcass traits (carcass weight, marbling score, loineye muscle area, backfat thickness and meat yield index) as covariations. The grading service data for 285,515 Hanwoo, which were evaluated by Animal Products Grading Service from 2005 to 2007, were used in this study. The partial R-square values of the fixed effects and the marbling score (MS), loineye muscle area, back-fat thickness, meat yield index and carcass weight (CW) on auction prices (AP) of the carcass and carcass price (CP) of the animals were estimated. The most important estimated trait in AP was MS. However, CW is the most important estimated trait on the CP and the MS also has secondly significant effect on the CP. In conclusion, MS as well as CW should maximize the farmer profits and establish a breeding scheme for Hanwoo.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.6
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• pp.501-505
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• 1991

To evaluate the suitability of solid-culm crops for silage, culm characteristics and the variation of solidness in several solid-culm and hollow-culm cultivars of wheat and triticale were examined both in the field and greenhouse. The degree of culm solidness and the voiume of air space in each internodes were measured at heading. The solidness of solid-culm were increased by the development of pith connected with vascular bundles. There was a variation in solidness among the crops tested. The degree of solidness in hollow -culm crops was 14.6% and 15.0% for 'Wonkwang' wheat and 'Shinkihomil' triticale, whereas in solid-culm crops the degree was 77.0-100% for durum wheats, 61. 0-95.8% for bread wheats and 18,7-57,0% for triticales. For 'Golden ball' which had the most solid culms among durum wheats tested higher solidness was observed in the greenhouse than the field, in the high internodes than low ones and in tiller culms than main stems. The solid-culm crops had a smaller air volume in internodes (1.01-2.30ml) than did 'Shinkihomil' (4.85ml) and this characteristics was considered to be advantageous for air removal and lactic fermentation at ensilaging.

• Korean Journal of Ichthyology
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• v.28 no.2
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• pp.67-71
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• 2016

Two Korean Rhodeus bittering fishes are known as having a unique reproduction system that the female deposits its egg inside freshwater mussels. Among them, R. ocellatus and R. uyekii show an ecological difference in feeding items and micro-habitat. Through a light microscope, the visual cells of the retina in the two species were investigated to get information between vision and environment related with habitat. The two fishes' eyes are spherical and R. ocellatus has relatively larger eyes. For the two species, the visual cells of the retina consisted of long single cones, short single cones, unequal double cones and rods. In the cones, all show a row mosaic pattern. Although the two species have a different micro-habitat in the wild, the component of the visual cells was very similar to each other.

• Journal of Radiation Protection and Research
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• v.36 no.2
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• pp.52-58
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• 2011

OSL dating for three hearths having the sequence of use and discard in No. 29 and 29-1 dwelling sites at Sogol cultural site was carried out. Resulting from the deconvolution of natural CW-OSL decay curve and thermal zeroing test, it was turned out that OSL signal was entirely composed of the heat- and light-sensitive fast component with high photoionization cross-section and all quartz OSL signals were thermally bleached under $300^{\circ}C$ which is the minimum temperature related to heating and cooking in Bronze age. After dose recovery test and plateau test, paleodose of each hearth sample was evaluated by using SAR method, and OSL age was determined from the ratio of paleodose to annual dose rate. For the purpose of the precision improvement of OSL age, Bayesian statistics was applied to each hearth's age and the archaeological sequence information. Finally, it could be concluded to the accurate use period of each hearth from the resultant OSL ages.

• Journal of Korea Water Resources Association
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• v.42 no.5
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• pp.425-432
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• 2009

Gongneung Weir 2 was built in 1970s to supply water for irrigation. For a long time, the weir was left uncared because of the land use change of the nearby area. The weir is 1.5 m high, and the stream in which the weir was installed has bed materials of fine sands to fine gravels. In 2006, the local government and residents agreed on uninstalling the weir, and the weir was removed completely on April 14. This paper reports the results of three field investigations for the study of the stream morphology change after the weir removal. Changes in grain size distribution, bed elevation, and cross section before and after the weir removal are provided and discussed. Net amount of sediment deposits within 1 km reach of the stream is estimated, and the results illustrates that the sediment process, leading to an equilibrium of the bed, progressed very swiftly, namely within 45 days.