• Journal of Microbiology and Biotechnology
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• v.26 no.7
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• pp.1285-1289
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• 2016

A split-column photobioreactor (SC-PBR), consisting of two bubble columns with different sizes, was developed to enhance the photon utilization efficiency in an astaxanthin production process from Haematococcus lacustris. Among the two columns, only the smaller column of SC-PBR was illuminated. Astaxanthin productivities and photon efficiencies of the SC-PBRs were compared with a standard bubble-column PBR (BC-PBR). Astaxanthin productivity of SC-PBR was improved by 28%, and the photon utilization efficiencies were 28-366% higher than the original BC-PBR. The results clearly show that the effective light regime of SC-PBR could enhance the production of astaxanthin.

• Korean Journal of Adult Nursing
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• v.23 no.3
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• pp.221-234
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• 2011

Purpose: The purpose of this study was to identify and describe phenomenological structures of the experiences of dietary life on elderly over 100 years old. Methods: The participants of this research included nine persons over the age of 100 years of age and ten family members who assisted in the dietary regime. Qualitative data were collected by individual in-depth interviews. Data were analyzed using Colaizzi's method of phenomenology. Results: The results of the research provide four categories and nine theme clusters. The categories included a rustic menu consisting of vegetables, grain-oriented traditional food, sensible dining table in harmony with nature, dietary life and emphasis on how to eat. The nine theme clusters were preference for fresh vegetable, preference of cooked potherb, boiled rice and cereal as main staple food, intake of soybeans, preference of native local foods, non-preference of unhealthy foods, select healthy and control food portion sizes for longevity, objection to light eating, and enjoying a meal. Conclusion: The findings of the study offer insight about the nutrition patterns among the people over 100 years of age.

• Journal of the Optical Society of Korea
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• v.13 no.2
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• pp.218-222
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• 2009

In this paper, we report the optical and structural properties of a bilayer circular filter fabricated by a glancing angle deposition technique. The bilayer circular filter is realized by a two-layer $TiO_2$ helical film with layers of opposite structural handedness. It is found that the bilayer circular filter reflects both right and left circularly polarized light with wavelength lying in the Bragg regime. The microstructure of the bilayer circular filter is also investigated using a scanning electron microscope.

• Current Optics and Photonics
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• v.3 no.4
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• pp.285-291
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• 2019

We have studied the behavior of light in the intermediate regime between a single nanoslit and an infinite nanoslit array. We first calculated the optical characteristics of a small number of nanoslits using finite element numerical analysis. The phase variance of the proposed nanoslit model shows a gradual phase shift between a single nanoslit and ideal nanoslit array, which stabilizes before the total array length becomes ${\sim}0.5{\lambda}$. Next, we designed a transmission-enhanced Fresnel zone plate by applying the phase characteristics from the small-number nanoslit model. The virtual-point-source method suggests that the proposed Fresnel zone plate with phase-invariant nanoslits achieves 2.34x higher transmission efficiency than a conventional Fresnel zone plate. Our report describes the intermediate behaviors of a nanoslit array, which could also benefit subwavelength metallic structure research of metasurfaces.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.57.1-57.1
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• 2021

K-SIM (KASI-Simulation) research project is dedicated to develop new numerical techniques in order to theoretically study galaxy formation and evolution. As the first step of the K-SIM, to model tidal stripping of galaxies with a very high resolution in a fully cosmological context, we invented the Galaxy Replacement Technique (GRT) that is very efficient and fast. The high resolution allows us to accurately resolve the tidal stripping process and well describe the formation of ultra-low surface brightness features in the galaxy cluster (㎶ < 32 mag/arcsec^2), such as the intra-cluster light, shells and tidal streams. I'll introduce how the GRT is designed and which science topics in low-surface brightness regime can be visited using the GRT.

• Development and Reproduction
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• v.14 no.1
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• pp.21-25
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• 2010

Nile tilapia (Oreochromis niloticus) are mouth-brooders so that the females holding eggs in their mouth sacrifice their somatic growth for reproduction. For this reason, artificial control of reproduction for the culture of this species has been of interest. Manipulation of photoperiod is an emerging technique for such purpose, but little information is available to establish appropriate photoperiod regime. To obtain necessary basic information, sexually mature females were individually accommodated to glass aquarium, and the spawning activity of these females were monitored for two years under natural photoperiod regime. Female tilapia spawned most frequently on March, April and May when the day length gradually increased from 11 hours to 14 hours and least frequently on September, October, November and December when the day length gradually decreased from 13 hours to less than 10 hours in the first year. The decrease of spawning frequency as day length decreased was also observed in the second year, although the increase of spawning frequency as day length increased was less clear. Spawning of female tilapia was less active when the night was dark due to the disappearance of moonlight (Dark Phase), compared to the Phase of Getting Lighter, Light Phase and Phase of Getting Darker. Results from this study suggest that long day length, particularly increasing phase, is favoured for active spawning of Nile tilapia, and that this species, as a tropical fish species, may utilize changing lunar phases as a secondary environmental cue for reproduction.

• The Journal of Fisheries Business Administration
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• v.32 no.2
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• pp.51-72
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• 2001

This study intends to review the development of Squid Angling Fisheries of Korea and Japan and subsequent changes in the fisheries regime as well as management conditions and to examine reorganization directions. Although catches and productivity are all increasing in Korea and Japan as the squid resource in the East Sea is improving, the number of fishing vessels and the conditions of fisheries management are showing a symmetrical relationship. The former is increasing in Korea and decreasing in Japan while the latter is aggravating in Korea and rather stable in Japan. And while the competition between the two countries for more fishing grounds and catches are not that serious since the resource is relatively increasing, the catch and price competition with other domestic fisheries is a more significant problem. Furthermore, even though light restriction is implemented in both countries in order to suppress over-competition, it is adopted as a means to curtail management costs and block over-investment rather than to adjust international or inter-fisheries circumstances. Japan has been implementing the TAC system on squid resources since 1998. However, it has a different meaning than as a resource management method in its original sense because it is based on the highest catch level of the past and takes into consideration the fishermen's management conditions. In case of Korea, it is necessary to establish a plan to strengthen its fisheries management competence to address its shrinking catch in the Japanese waters. The developments mentioned so far have appeared amidst the increase of squid resources, and if such conditions disappear, problems such as international allocation of catches and fishing seasons, access to fishing grounds, and domestic conflicts among different fisheries will emerge.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.8
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• pp.1301-1309
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• 2020

Objective: To evaluate the use of nurse sows and post-weaning nutrition strategies for low wean weight (WW) pigs on lifetime growth and efficiency. Methods: Animals (n = 270) were assigned to one of five treatments at 28 d. Low WW pigs (<6 kg) were either weaned and offered a special dietary regime recommended for low WW pigs (WEAN) or placed on a nurse sow (NURSE) and weaned at 49 d. Normal WW pigs (9 kg) (NORM) were also weaned at 28 d. After weaning, NORM and NURSE pigs were offered either a 'high' (4 kg/pig of starter 1 diet followed by 8 kg/pig of starter 2 diet) or 'low' (8 kg/pig of starter 2 diet) starter diet allowance in a 2×2 factorial arrangement. A typical grower diet was then offered, followed by a typical finisher diet until 147 d of age. Results: NORM pigs where heavier throughout their life compared to NURSE pigs (91.4 kg vs 76.2 kg at 147 d; p<0.001). WEAN pigs were heavier at 70 d compared to NURSE pigs (23.9 kg vs 21.0 kg; p<0.001), but there was no significant difference at 147 d between NURSE and WEAN treatments. NURSE pigs had reduced feed intake throughout the finishing period (1.6 kg/d; p<0.001) compared to WEAN (2.0 kg/d) and NORM (1.9 kg/d) pigs. Feed conversion ratio (FCR) of NURSE (2.20) was lower than NORM and WEAN during the finishing period (2.40 and 2.79, respectively). Conclusion: Extended (up to 49 d) nursing for low WW pigs resulted in improved FCR during the finishing period, but no overall improvement in growth rate compared to low WW pigs weaned at 28 d and offered a specialised starter regime. Normal WW pigs where significantly heavier than low WW pigs throughout the study.

• Convergence Security Journal
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• v.17 no.2
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• pp.127-135
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• 2017

Today, Kim Jong-un, the third-hereditary regime in North Korea, is committing Nuclear Provocation more aggressively than the past when Kim Il-sung and Kim Jong-il dominated. Past South Korea government had suggested plans to restrain the provocation from North Korea and bring stabilization in the Korean Peninsula. However, consequentially it was limited to the primary role of the President. When President Trump takes over the government in February 2017, it has attracted the expectation about the issues occurred on the Korean Peninsula due to the pledge that he promised during the presidential election and his govern style. However, various speeches about the Korean Peninsula that he spoke recently made situations depressed about what South Korean currently encounters. Furthermore, previous regime in North Korea has laid the foundation for Kim Jong-un to be obsessed more on the nuclear and missile which has led him to provoke more imprudently by highlighting the light weight, advanced, and various kinds of nuclear and missiles. Thus, we would like to propose counter measures in order for South Korean government to handle and solve the issues that they encounters by themselves based on North Korea's Nuclear Provocation instead of relying on other countries to get involved and help.

• Journal of the Korean Vacuum Society
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• v.14 no.3
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• pp.143-146
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• 2005

A new method of x-ray photon correlation spectroscopy (XPCS) using coherent x-rays is developed recently for probing the dynamics of surface height fluctuations as a function of lateral length scale. This emerging technique applies the principles of dynamic light scattering in the x-ray regime. The short wavelength and slow time scales characteristic of XPCS extend the phase space accessible to scattering studies beyond some restrictions by light and neutron. In this paper, we demonstrate XPCS to study the dynamics of surface fluctuations in thin supported polymer films. We present experimental verification of the theoretical predictions for the wave vector and temperature dependence of the capillary wave relaxation times for the supported polymer films at melt for the film thicknesses thicker than 4 times of the radius of gyration of polymer. We observed a deviation from the conventional capillary wave predictions in thinner films. The analysis will be discussed in terms of surface tension, viscosity and effective interactions with the substrate.