• Journal of Information Management
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• v.20 no.1
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• pp.66-85
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• 1989

The purpose of this study is to verify the following two hypotheses by using a test collection of 3.815 documents on the subject of chemistry. First hypothesis is that a Markov chain model can be used t9 describe and predict authors' movements among subareas of a discipline. Second hypothesis is that a transition matrix of the Markov chain can be applied to describ the intellectual structure of a discipline en the multidimensional space. The results of this study have shown that the Markov chain is a good model to be used to study the movement of korean chemists in 7 subtopics in chemistry and understand the intellectual structure of chemistry.

• Korean Journal of Food Science and Technology
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• v.27 no.1
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• pp.36-40
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• 1995

Yam(Dioscorea) tubers were used as one of the dietary starches in Korea, China and Japan because of its characteristic properties. Yam tubers were powdered after freeze drying the sliced tubers to investigate carbohydrates. Chemical properties such as proximate components and carbohydrates were studied using three varieties of Korean yams, namely. D. batatas, D. aimadoimo and D. japonica. The proximate components of yam tubers showed that the major components of Korean yam tubers were carbohydrates and moisture. The main components of free sugars in yams were identified as fructose, glucose, sucrose and maltose. In addition to these four sugars, there were two unidentifiable peaks whose areas are too big to ignore. These results were obviously different from other reported data of free sugars in yams. The main components of total sugars were mannose and glucose.

• Korean Journal of Plant Taxonomy
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• v.45 no.4
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• pp.380-390
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• 2015

The morphological characters were observed in six taxa in the genus Dioscorea of Korea (D. polystachya, D. japonica, D. nipponica, D. quinqueloba, D. tenuipes, and D. dokoro). The underground structure and the formation of bulbil were useful characters for separating sect. Enanatiophyllum from sect. Stenophora. The important characters for discriminating taxonomic entities were as follows: the position of the anther and the shape of the pistil in the microstructural characters, including the protuberance of the base of the petiole, the shape and color of the flower, the shape of the fruit, and the shape of the seed wing. Based on the results, a key to Korean Dioscorea is provided and the distribution of these species in Korea is described.

• Resources Recycling
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• v.9 no.5
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• pp.28-32
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• 2000

In this study, the new processing method to produce magnetite for mono-component black toner was studied using spray roaster. The produced magnetite is compared with TMB 125 made by Magnox, USA. When the weight ratio of the ferrous chloride and the ferric chloride is varied from 3:7~7:3 under $N_2$ atmosphere, the 100% major phase of magnetite is obtained. However, when the content of he ferrous chloride is higher than 70wt%, the content of FeO is increased. The phase of $\Gamma-Fe_2O_3$ is shown in th range of over 70wt% of the ferric chloride. The magnetite produced by spray roasting has a saturation magnetization of 80~85 emu/g and a coercivity of 110~130 Oe. The shape of the particle is irregular sphere and hte size of the magnetite is the range of $0.3~0.5\mu\textrm{m}$. It is shown that the magnetite made by spary roasting is enough to apply to the magnetic material of toner.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.9
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• pp.1243-1248
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• 2010

The physiological activities of Strychnos nux-vomica extracts were investigated through the total phenolic contents (TPC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (RSA), comet assay, and $\alpha$-glucosidase inhibitory activity. S. nux-vomica extracts were prepared with methanol, ethanol, and acetone. The methanol extract showed the highest phenolic content (71 mg/100 g gallic acid equivalents). Pretreatment with S. nux-vomica extracts resulted in significant reductions in oxidative DNA damage at all of the concentrations tested ($1{\sim}50\;{\mu}g/mL$). The $\alpha$-glucosidase inhibitory activity of a methanol extract was 12.8% at the concentration of 1 mg/mL. Therefore, these results indicate that S. nux-vomica might be a noble potential candidate exhibiting antioxidant and $\alpha$-glucosidase inhibitory activity.

• Journal of Korea Water Resources Association
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• v.40 no.8
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• pp.643-654
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• 2007

This study proposes and evaluates a methodology for deriving the rainfall intensity- duration-frequency relationship for durations less than 10 minutes used for designing drainage systems in small urban catchments and roads. The method proposed in this study is based on the Moupfouma distribution, which has been evaluated by applying it to the rainfall data at the meteorological Seoul station. Summarizing the results is as follows: (1) The frequency analysis results using minutely rainfall data was found not to be corresponded with the extrapolation of that by the Ministry of Construction and Transportation (2000). (2) The annual maxima minutely rainfall data derived by applying the Moupfouma distribution to the accumulated 60-minute data was found to well reproduce the characteristics of those of observed. (3) The rainfall intensity-duration-frequency relationship derived by applying the Moufouma distribution to the accumulated 50-minute data and hourly data was found insignificant.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.1
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• pp.37-46
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• 2017

Thermal Marangoni flow has been observed inside droplets on heated surfaces, finally resulting in a coffee stain effect. This study aims to visualize and control the thermal Marangoni flow by employing periodic vertical vibration. The variations in the contact angle and internal volume of the droplet as it evaporates is observed by using a combination of continuous light and a still camera. With regard to the internal velocity, the particle image velocimetry system is applied to visualize the internal thermal Marangoni flow. In order to estimate the internal temperature gradient and surface tension on the surface of a droplet, the theoretical model based on the conduction and convection theory of heat transfer is applied. Thus, the internal velocity increases with an increase in plate temperature. The flow directions of the Marangoni and gravitational flows are opposite, and hence, it may be possible to control the coffee stain effect.

• Journal of IKEEE
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• v.24 no.2
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• pp.453-460
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• 2020

This paper, UHF band integrated communication antenna for ship communication is designed as a flat type that can be mounted on the integrated mast among integrated communication antennas such as integrated communication, ship communication, broadcasting, and telephone of the ship. The unified mast mounted antenna is an integrated communication antenna applied to the Navy's KDDX, which is an optimized type of integrated communication antenna including a 'composite slope' structure including operational capability, survivability, and improved operability and maintainability. The existing rotary radar and a plurality of monopole-type communication antennas were changed from an irregularly attached shape to the mast exterior to an integrated mast shape including a flat-type integrated communication antenna. the radar reflection area index (RCS) is significantly lowered and compared to overseas products. The goal is to develop a gain broadband antenna.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.7
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• pp.695-701
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• 2013

The suppression of a thermocapillary flow (Marangoni flow) by a nonionic surfactant is experimentally investigated for evaporating pure water droplets on hydrophobic substrates. The experiment shows that as the initial concentration of the surfactant increases, the velocity and lifetime of the flow monotonically decrease. The result confirms the no-slip boundary condition at a liquid-air interface, which is explained on the basis of the previous model regarding the effect of surfactants on the no-slip condition. Interestingly, at an initial concentration much less than a critical value, it is found that depinning of the contact line occurs during the early stage of evaporation, which is ascribed to a reduction in the contact angle hysteresis owing to the presence of the Marangoni flow.

• Korean Journal of Food Science and Technology
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• v.17 no.3
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• pp.219-222
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• 1985

Fatty acid patterns were determined for 11 and 19 brands of household margarines from the local markets in Korea in 1983 and 1984, respectively. Gas-liquid chromatographic analyses on OV-275 column showed that the average content of total trans fatty acids was 18% ranging from 6.2 to 35.5% for the margarines produced in 1983. The prototype of trans fatty acids was trans-octadecenoic acid. There was a small amount of c, t-or t, c-octadecadienoic, whereas there were practically no t, t-octadecadienoic acid. Trans fatty acids was increased in proportion to linoleic acid contents. For the margarines produced in 1984.. percentage of trans fatty acids tended to decrease, while that of linoleic acid was increased as compared with the corresponding values for the 1983 products. Thus, the P/S ratio was increased markedly in the soft type margarines produced in 1984. However, Korean margarines contained seemingly less linoleic acid than that contained in Japanese margarines.