• Polymer(Korea)
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• v.32 no.4
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• pp.359-365
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• 2008

We have fabricated a novel thermo-responsive nanofibrous surfaces by grafting PIPAAm by electron beam irradiation onto poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV) nanofibrous mats. The electrospun PHBV nanofiber structures revealed randomly aligned fibers with average diameter of 400 nm. Increased atomic percent of nitrogen was observed on the PIPAAm-grafted PHBV mats after electron beam irradiation determined by ESCA. The amounts of PIPAAm-grafted onto PHBV films were $6.49{\mu}g/cm^2$ determined by ATR-FTIR. The PIPAAm-grafted surfaces exhibited decreasing contact angles by lowering the temperature from 37 to $20^{\circ}C$, while ungrafted PHBV surfaces had negligible contact angle change. This result indicates that PIPAAm surfaces, which are hydrophobic at the higher temperature, became markedly more hydrophilic in response to a temperature reduction due to spontaneous hydration of the surface-grafted PIPAAm. Thermo-responsive nanofibers showed good tissue compatibility. Cultured cells were well detached and recovered from the surfaces by changing culture temperature from 37 to $20^{\circ}C$.

• Fire Science and Engineering
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• v.34 no.2
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• pp.94-96
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• 2020

In November 2013, a case of sustained combustion of a female body was encountered in a Korean farming village. The body was almost completely incinerated from the neck to the knees, and other parts of the body, such as the head, arms, lower legs, and feet, were slightly damaged. The most likely external ignition source was the flame from a matchstick. The elderly woman was found incinerated on the floor of the living room, while other objects in the house were largely undamaged except for having a brown oily or greasy coating. Flammable substances were not detected from the woman's intact pieces of clothing and socks, and her muscular tissues did not contain toxic chemicals. The concentration of carboxyhemoglobin in her peripheral blood was 11% and that of ethyl alcohol in her aqueous humor was below 0.010%. An autopsy failed to determine the exact cause of death because of excessive charring.

• Journal of Navigation and Port Research
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• v.28 no.6
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• pp.481-489
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• 2004

Ship collisions and grounding continue to occur regardless of continuous efforts to prevent such accidents. With the increasing demand for safety at sea and for protection of the environment, it is of crucial importance to be able to reduce the probability of accidents, assess their consequences and ultimately minimize or prevent potential damages to the ships and the marine environment. Numerical simulations for actual collision problem are conducted with a special attention with respect to finite element size, fracture criteria and material properties, which require a careful consideration to improve the accuracy. A parametric analysis varying colliding speed, angle, design loading condition is conducted using nonlinear finite element analysis method for 46,00 dwt Product/chemical carrier. The relationship between the absorbed energy and indentation are derived quantitatively using the insights observed from this study, and a novel design concept for assessing the anti-collision performance are proposed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.715-722
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• 2020

This paper proposes a design verification method based on system dynamics for offshore separation systems. Oil and gas separation systems are key components of offshore oil platforms; these systems determine the competitiveness of engineering, procurement, and construction (EPC) projects, especially in terms of added value. However, previous research on design verification has been limited to the process and deliverables of design. To address this, the study aims to develop a comprehensive design verification method and the associated functions from the perspective of project management, for the entire project life-cycle of offshore structures. The proposed methodology for design verification is expected to contribute toward effective and detailed designs as well as improve the competitiveness of EPC companies in constructing of shore structures during the early design stages. We first analyzed the separation system of the FPSO using the design verification method adopted by advanced countries and compared it with the system dynamics process formalized as ISO 15288. Subsequently, a tailored process for the design verification of the offshore structure was derived. It is shown that the proposed design verification method can be applied to the front-end engineering design process of of shore structures. Moreover, it can contribute toward the successful performance of offshore projects in the future and also minimize design changes and critical risks during the construction of these offshore structures.

• Journal of Navigation and Port Research
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• v.30 no.6 s.112
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• pp.439-446
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• 2006

In ship structures many of the structural plates have cutouts, for example, at inner bottom structure, girder, upper deck hatch, floor and dia-frame etc. In the case where a plate has a cutout it experiences reduced buckling and ultimate strength and at the same time the in-plane stress under compressive load produced by hull girder bending will be redistributed In general, actual ship structure adopted reinforcement of stiffener around the cutout in order to preventing from buckling so it need to examine a buckling and ultimate strength behaviour considering a cutout because In many ship yards used class rule for calculating buckling strength but it is difficult to evaluate perforate stiffened plate with random size. In the present paper, we investigated several kinds of perforated stiffened model from actual ship and then was performed finite element series analysis varying the cutout ratio, web height, thickness and type of cross-section using commercial FEA program(ANSYS) under compressive load.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.1
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• pp.85-91
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• 2004

In this study, we evaluated the crow's feet of 152 Korean women by using visual assessment established by our research group and mechanical assessment, Skin Visiometer SV 600. The volunteers were divided into 3 groups according to age; the group I of 30's was 43, the group II of 40's was 75, the group III of 50's was 34. The wrinkle score by visual assessment showed tendency to increase according to age and was statistically significant different among those three age groups (P 〈 0.05). But there was no significant difference between the left and the right of crow's feet. The 5 wrinkle parameters (RI, R2, R3, R4, R5) of mechanical assessment varied as age and the Rl, R4, and R5 showed statistically significant difference among three age groups (P 〈 0.05). However there was no significant difference between the left and the right of crow's feet. The volunteers were divided into 3 groups according to wrinkle score; (0-3 grade for group A, 4-6 grade for group B, 7-9 grade for group C). Only R4 and R5 showed significant difference between group A and group C (P 〈 0.05). It was suggested that visual scoring criteria applied in this study was related to R4 and R5 and was useful in investigating in fine wrinkles.

• Journal of the Korean Magnetics Society
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• v.7 no.1
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• pp.13-18
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• 1997

The effects of the various raw material composition and sintered temperature on the physical properties of Ni-Zn ferrite have been investigated. They turned out to be spinel structure by X-ray diffraction and the size of grain from microscope was from 6 ${\mu}{\textrm}{m}$ to 16 ${\mu}{\textrm}{m}$. As the sintering temperature was increased from 1030 $^{\circ}C$ to 1070 $^{\circ}C$, the initial permeability and magnetic induction has increased and the both of Q factor and coercive force has decreased. The coercive force and curie temperature were almost the same at each specimen. Their values were about 0.20 Oe and 220 $^{\circ}C$. The frequency of specimen will used in the range from 400 kHz to 20 MHz. The basic composition of $Ni_{0.14}Zn_{0.64}Cu_{0.22}Fe_2O_4$ (specimen B) sintered at 1050 $^{\circ}C$ shows the best results at magnetic induction($B_r & B_m$).

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.3
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• pp.269-274
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• 1987

A laboratory experiment was conducted to find out the effect of inoculation with plant growth of associative $N_2$-fixing bacteria on the combination of eight different rice seedling with seven different associative $N_2$-fixing bacteria in which were isolated and identified from grasses and rice in saline and reclaimed saline paddy soil. Those were examined in N-free axenic culture medium. The result of this experiment exemplified the contribution of associative $N_2$-fixing bacteria to their host plant were varied much by the combination of rice cultivars and bacterial strains. Acetylene reduction ($N_2$-fixation) activity seems to be more variable with respect to the combination of rice cultivars and bacterial strains. The relationship between acetylene reduction activity and rice performance such as dry matter weight, plant height, root length, and number of root were statistically insignificant. However, in comparision with the control, the dry matter yield of Annapuruna was increased by inoculation of all the seven bacteria strains. Among the seven rice cultivars, the average acetylene reducing activity was the highest in Annapuruna, and Shingwang, and the lowest in IR-8 inoculated with Pseudomonas sp H8. Among the seven bacterial strains the highest acetylene reducing activity was obtained by the combination of Shingwang with Pseudomonas sp H8.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.4
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• pp.359-367
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• 1987

A method for evaluating bacterial chemotactic responses toward several single of combined sugars and sterile mucilage from the different rice cultivars had been tested. Bacterial genus of Azospirillum, Pseudomonas and Agrobacterium were specially identified from the histosphere of different rice cultivars and graminea grasses in saline and reclaimed saline paddy soil. To evaluate chemotaxis of these strains a modification of Fendrik channel method was used. Under this condition Azospirillum lipoferum Ecc 3-1 reacted stereoisomerically fomulating the single migration ring while Agrobacterium radiobacter Ecc 1-1 and Pseudomonas sp Ecc 4-1 did not. Strains specificities of chemotaxis to the single sugar such as D(+)-glucose and D(+)-fructose were less prominent than malic and citric acid. Chemotactic responses to the combined sugar such as D-galacturonic acid and the L-aspartate were found high attracting reaction than other combined sugars. Chemotaxis of associative $N_2$-fixing bacteria to the root exudates of different rice cultivars were differed among bacterial strains and rice cultivars.

• Proceedings of KOSOMES biannual meeting
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• 2005.05a
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• pp.141-146
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• 2005

Ship have cutout inner bottom and girder and floor etc. Ship's structure is used much, and structure strength must be situated, but establish new concept when high stress interacts sometimes fatally the area. There is no big problem usually by aim of weight reduction, a person and change of freight, piping etc. Because cutout's existence grow up in this place, and, elastic buckling strength by load causes large effect in ultimate strength. Therefore, stiffened perforated plate considering buckling strength and ultimate strength is one of important design criteria which must examine when decide structural concept at initial design. Therefore, and, reasonable buckling strength about perforated stiffened plate need to ultimate strength limited design . Calculated ultimate strength varied several web height and cutout's dimension, and thickness in this investigated data. Used program(ANSYS) applied F.E.A code based on finite element method.