• International Journal of Precision Engineering and Manufacturing
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• v.9 no.4
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• pp.57-62
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• 2008

The aim of this investigation was to extract the fatigue properties at the designated fatigue life of copper foil and observe the mean stress and stress amplitude effects on both the fatigue life and the corresponding surface morphology. Tensile tests were performed to determine the baseline monotonic material properties of the proportional limit and ultimate tensile strength. Constant amplitude fatigue tests were carried out using a feedback-controlled fatigue testing machine. The mean stress and the stress amplitude were changed to obtain the complete nominal stress-life curves. An atomic force microscope was utilized to observe the relationship between the fatigue damage and the corresponding changes in surface morphology. A Basquin's exponent of-0.071 was obtained through the fatigue tests. An endurance limit of 122 MPa was inferred from a Haigh diagram. The specimen surface became rougher as the number of fatigue cycles increased, and there was a close relationship between the fatigue damage and the surface roughness evolution.

• Composites Research
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• v.28 no.4
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• pp.182-190
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• 2015

The phenomenological evolution laws of damage can be defined either based on residual life or residual strength. The failure of a specimen can be defined immediately after or before fracture. The former is called in this paper by "failure defined by approach I" and the latter "failure defined by approach II." Usually at failure there is a discontinuity of loading variables and, because of this, damage at failure is discontinuous. Therefore the values of damage at failure by two different approaches are not the same. Based on this idea the sequence effects of the phenomenological evolution law of damage given by $dD/dN=g(D)f({\Phi})$ were studied. Thin-walled graphite/epoxy tubes consisting of four of $[{\pm}45]_s$ laminates were used for the experimental study of sequence effects and the effects of mean stress on fatigue life. It was found that the sequence effects in two step uniaxial fatigue for $[{\pm}45]_s$ graphite/epoxy tubular specimen showed that a high-low block loading sequence was less damaging than a low-high one.

• ALGAE
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• v.28 no.2
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• pp.203-211
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• 2013

Dunaliella salina and Dunaliella bardawil are well known for carotenogenesis, the overproduction of carotenoids, under stress conditions. The effect of high light (HL) and low light (LL) on the growth, morphology, photosynthetic efficiency, and the ${\beta}$-carotene and zeaxanthin production of D. salina CCAP 19/18 and D. bardawil was investigated and compared. Both strains showed similar growth kinetics under LL growth condition, but D. salina CCAP 19/18 was faster. As the light intensity increased, D. salina CCAP 19/18 cells were elongated and D. bardawil cells became larger. Both strains showed decrease of the maximum quantum yield of PSII ($F_v/F_m$) and election transport rate (ETR) under HL growth condition and D. salina CCAP 19/18 was less liable to the light stress. Both strains had about 1.8 and 5 times difference in the $O_2$ evolution rate at LL and HL conditions, respectively. The ${\beta}$-carotene and zeaxanthin production were increased as the light intensity increased in both strains. D. bardawil was more sensitive to light intensity than D. salina CCAP 19/18. The possible application of D. salina CCAP 19/18 as a carotenogenic strain will be discussed.

• Molecules and Cells
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• v.22 no.3
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• pp.300-307
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• 2006

Brassica rapa ssp. pekinensis (Chinese cabbage) is an economically important crop and a model plant for studies on polyploidization and phenotypic evolution. To gain an insight into the structure of the B. rapa genome we analyzed 12,017 BAC-end sequences for the presence of transposable elements (TEs), SSRs, centromeric satellite repeats and genes, and similarity to the closely related genome of Arabidopsis thaliana. TEs were estimated to occupy 14% of the genome, with 12.3% of the genome represented by retrotransposons. It was estimated that the B. rapa genome contains 43,000 genes, 1.6 times greater than the genome of A. thaliana. A number of centromeric satellite sequences, representing variations of a 176-bp consensus sequence, were identified. This sequence has undergone rapid evolution within the B. rapa genome and has diverged among the related species of Brassicaceae. A study of SSRs demonstrated a non-random distribution with a greater abundance within predicted intergenic regions. Our results provide an initial characterization of the genome of B. rapa and provide the basis for detailed analysis through whole-genome sequencing.

• Animal Systematics, Evolution and Diversity
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• v.39 no.2
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• pp.72-76
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• 2023

The spider fauna of mountains, including national parks, in Korea was intensively surveyed in 2018-2019. During the seasonal surveys, males of Clubiona bakurovi Mikhailov, 1990 (family Clubionidae Wagner, 1887) and Otacilia ansula sp. nov. (family Phrurolithidae Banks, 1892) were collected from shrub foliage and leaf litter, respectively, in mountainous mixed forests. The males of Otacilia ansula sp. nov. can be easily distinguished from those of other its congeners by the slender and hook-shaped retrolateral tibial apophysis, ovoid distal tegular apophysis, and one dorsal spine on the femur with seven pairs of ventral spines on the tibia of leg I. This study provides descriptions of these two species with diagnosis, measurements, and morphological photographs.

• Animal Systematics, Evolution and Diversity
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• v.37 no.4
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• pp.330-334
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• 2021

The genus Clubiona Latreille, 1804 is the most diverse and largest one in the family Clubionidae Wagner, 1887. Twenty-nine species of the genus have been described in various ecosystems from Korea to date. Clubiona semicircularis Tang, Song and Zhu, 2005 which was formerly only known in China and Clubiona ansa n. sp. were collected with a sweep net on the foliage of the shrubs in mixed forests from mountains and agricultural landscape during a seasonal survey of the spider fauna in Korea. This study describes these two species with a diagnosis, measurements, and morphological illustrations. In addition, the female of C. semicircularis is described with a diagnosis for the first time from the present study.

• Animal Systematics, Evolution and Diversity
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• v.26 no.1
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• pp.79-82
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• 2010

new species Iotrochota rutzleri n. sp. (Demospongiae: Poecilosclerida: Iotrochotidae) was collected from intertidal zone, Sinyangri, Seongsanpo, Jejudo Island, Korea during 2008-2009. Iotrochota rutzleri n. sp. is similar to I. baculifera Ridley, 1884 in composition of spicules and skeletal structure. However, it is different in size of spicules, growth form and colour. All spicules of this new species are smaller than those of the latter.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2005.04a
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• pp.56-56
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• 2005

• Animal Systematics, Evolution and Diversity
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• v.25 no.2
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• pp.145-158
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• 2009

Four species of the genus Atylus belonging to the family Dexaminidae are reported from the eastern and southern coasts of Korea. Three of these species are redescribed as new records of this country: Atylus (Atylus) ekmani (Gurjanova), A. (A.) matsukawaensis Hirayama and Takeuchi and A. (Kamehatylus) japonicus Nagata.

• Animal Systematics, Evolution and Diversity
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• v.24 no.1
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• pp.143-145
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• 2008

The first known males of the spider Alloclubionoides ovatus (Paik, 1976) from Korea are described with detailed illustrations, spination of each leg and trichobothrium patterns. Males have a large conductor expanded curvedly 'p'-shaped with thin membrane of distal end surrounded the linear embolus and slender embolus penetrating tegulum.