• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2A
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• pp.174-180
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• 2004

The World Radiocommunication Conference in year of 2000 adopted new Plans as well as Lists for BSS and its feeder-link in the Regions 1 and 3, based on the new technical criteria such as small size of antenna and low satellite power. Since the new Plans and Lists were based on new technical criteria, ITU was requested to review the relevant regulatory procedures and sharing criteria of broadcasting satellite networks contained in Appendices 30 and 30A of Radio Regulations. Korean BSS network at 116$^{\circ}$E was chosen for the study and ITU S/W (MSPACEG) was used. We analyzed the interference effects from adjacent BSS networks to Korean BSS network using parameters of an antenna diameter and polarization of receiving earth station. The analysis shows that it is difficult to co-operate BSS networks both at 116$^{\circ}$E and 113$^{\circ}$E, however, it is possible to use small antenna (i.e. 45cm) in frequency sharing among BSS networks with 6$^{\circ}$ orbital separation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.4
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• pp.401-407
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• 2014

In this paper, the effect of cohesive laws on the finite element analysis of crack propagation using cohesive elements is investigated through three-point bending and double cantilever beam problems. The cohesive elements are implemented into ABAQUS/Standard user subroutines(UEL), and the shape of cohesive law is varied by changing parameters in polynomial functions of cohesive traction-separation relations. In particular, crack propagation behaviors are studied by comparing load-displacement curves of the analysis models which have different shapes of cohesive laws with the same values of fracture energy and cohesive strength. Furthermore, the influence of the element size on crack propagation is discussed in this study.

• Journal of Life Science
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• v.17 no.4 s.84
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• pp.455-461
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• 2007

Assessments of population genetic structure and diversity can be of value in formulating management plans for threatened eelgrass(Zostera maim). Using randomly amplified polymorphic DNA markers, we found evidence of significant genetic structure among the populations of eelgrass sampled at three areas(Geojedo, Gaedo, and Jedo). A highly isolated(>100 km apart) population from the Geojedo had a long genetic distance(0.16), whereas the populations from the Gaedo and Jedo(<10 km apart) exhibited far less distance(0.08). The analysis of similarity within population showed that Geojedo was over 70%, which was of lower value than of Gaedo and Jedo. Based on these results, we realized that heterogeneous population was in accordance with geographic separation. This is caused by limited seed dispersal and interrupted gene flow, although the sample size is small.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.1
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• pp.178-189
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• 1989

An experimental study has been performed to study the effect of the base slant angle of a 1/10 scale two-dimensional vehicle-like body on its wake flow including the recirculating region, where the simplified shape of the body has been originated from a profile of a domestic passenger car. In the case of a Reynolds number based on the length of the model R=7.96*10$^{5}$ , the surface pressure coefficient, the mean velocity and the turbulent stresses have been measured, while the flow visualization technique using wool tuft has been adopted as well. When the base slant angle of the model is 15.deg., the free stream flowing parallel to the slant is observed to be separated from the lower edge of the slant, thus forming the smallest recirculating region. When the base slant angles are 30.deg. and 45.deg., the free streams are separated from the upper edge of the slant and the sizes of the recirculating zones are observed to be almost the same as when the base slant angle is 0.deg. From these observations, it is conjectured that between the base slant angles of 15.deg. and 30.deg. there exists a critical angle at which the size of the recirculating region becomes minimum and as the slant angle becomes larger than this critical angle the separation line moves along the slant towards the rear edge of the roof. Through the flow visualization technique, the existence of the two counter-rotating bubbles in the recirculating region has been clearly observed and verified.

• Applied Biological Chemistry
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• v.43 no.1
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• pp.18-23
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• 2000

stract : Fourteen varieties of glutinous rices were examined on amylopectin fine structure and physicochemical properties of starch granules. The amylopectin chain length distribution and short chain/long chain ratio were investigated by enzymatic treatments followed by high-performance size-exclusion chromatographic separation. Chain length distribution profiles of the isoamylase-debranched amylopectins showed distinct patterns according to varieties. Beongok showed the highest short chain/long chain ratio, while TP2579A1 showed the lowest one. Sharebyeo-152-1-B showed the highest hydrolysis rate to 15% $H_2SO_4$, while Sandong 47 showed the lowest one. Fourteen varieties of rice starch granules showed A-type pattern on X-ray diffractograms. Non-gelitinized starch granules from Keochang 1 and Beongok had almost 100% hydrolysed by glucoamylase for 3 hrs at $370^{\circ}C$.

• Membrane Journal
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• v.30 no.3
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• pp.200-204
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• 2020

1,3,5-benzenetricarbonyl trichloride is a chemical substance in which three acyl chlorides are located at 1,3,5 position in the benzene ring, and is an important chemical for the area where the good physical and chemical properties are required through high degree of crosslinking. In particular, it is possible to form a three-dimensional structure having a certain pore size, it is used in various separation and purification fields. However, the high reactivity of acyl chloride has the advantage of a fast reaction rate, which means that it is difficult to control chemically to have a certain performance in other aspects. Therefore, in this study, we observed how the chemical change of 1,3,5-benzenetricarbonyl trichloride affected the membrane performance.

• Analytical Science and Technology
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• v.30 no.1
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• pp.1-9
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• 2017

Starch is a mixture of amylose (AMY) and amylopectin (AMP) which are different in physical properties such as molar mass (M), rms radius ($R_g$) and hydrodynamic diameter ($d_H$). The rheological and functional properties of starch are influenced by various factors including the molecular size, molar mass distribution (MD) and the concentration ratio of AMY and AMP. It is also important to analyze proteinaceous material in starch as they affect the flavor and texture of food to which starch is added. In this study, asymmetrical flow field-flow fractionation (AF4) was employed for separation and quantitation of AMY and AMP in starches (Amaranth, potato, taros and quinoa). AF4 was coupled with a multi-angle light scattering (MALS) and a refractive index (RI) detector for determination of the absolute M, MD and molecular structure. It was found that AMP has the M and $R_g$ ranging $3.7{\times}10^7{\sim}6.5{\times}10^8g/mol$ and 84 ~ 250 nm, respectively. Also the existence of branch was confirmed in higher M. In addition, proteinaceous material in starch was analyzed by AF4 coupled with a fluorescence detector (FS) after fluorescence-labeling. AF4-FS with fluorescence-labelling showed a potential for investigation on existence of proteinaceous material and the interaction between proteinaceous material and polysaccharide in starch.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.4
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• pp.466-475
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• 2010

This study intends to present a direction for the better reforming of fishers'onboard living conditions and proposals for preparing for ratification of the Work in Fishing Convention by means of making a comparison between standards on recent national fishing vessel accommodation facilities and standards on the Work in Fishing Convention and Its Recommendation, 2007, ILO. For the most part of standards on national fishing vessel accommodation facilities are somewhat insufficient to satisfy the provisions in Annex III of the Convention. Considering by items on fishing vessel accommodation facilities, the standards on insect protector, noise and vibration, heating and air conditioning, lighting, persons per sleeping room, recreational facility are not provided in national law. Headroom, separation of accommodation, sleeping room floor area, mattress size, mess room, galley and food storage are partially sufficient for the Convention. In case of sanitary facilities, national standards are not sufficient for the Convention. The other side, facilities related safety of ship and crew such as emergency escape etc., are fully sufficient for the Convention. These insufficiencies caused by different types of fishing vessel depend on originality of fishing method and practices. In the comparison between equivalent tonnage about vessel's length on convention and calculated tonnage of national existing fishing vessel, the difference are 226tons about length 24m and 501tons about length 45m. For that reason, headroom, persons per sleeping room, cabin of sicker and injured, sanitary facilities may decide to use gross tonnage in place of length (L) and the alleviating measure basis of convention. But in case of standards on sanitary facilities which are unsufficient for the Convention, specially in coastal fishing vessel length basis should be adopted with alleviating basis for less than length 24m.

• Applied Chemistry for Engineering
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• v.5 no.2
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• pp.305-312
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• 1994

The fed-batch process which combinded high selectivity of affinity chromatography and membrane process was developed. The mixture of trypsin and chymotrypsin, having almost the same molecular weight and the chemical structure, were used as model enzymes. The water soluble polymer having more affinity for trypsin and celluose acetate membrane gelated in 50vol.% ethanol for removing free enzymes and retentating trypsin-affinity polymer complex simutaneously were used in this system. The membrane pore size was controlled by ethanol concentration in the gellation bath, and the affinity polymer was prepared by polymerization of acrylamide with N-acryloyl-m-aminobenzamidine at $4^{\circ}C$. The trypsin could be effectively concentrated by utilizing an affinity polymer and a prepared UF-50 ultrafiltration membrane. As a result, 86% purity trypsin was recovered by the current purification process.

• Journal of Biosystems Engineering
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• v.14 no.4
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• pp.272-281
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• 1989

It is desirable for the vertical wind tunnel which can build uniform air flow across the vertical duct to be used for the purpose of the investigation of the aerodynamic properties of grains. This study was conducted to examine how the air velocity profile in the vertical duct is influenced by the various alternations of the elements of the wind tunnel, and to prepare design guidance of the vertical wind tunnel which can be used for investigating aerodynamic properties of grains. In addition, several tests were conducted to locate the test section which can be applicable for determining the terminal velocity of grain. The following conclusions were obtained from the study: 1. The size and the location of the outlet of the plenum chamber should be determined such that the outlet air flow is less affected by the air flow and the back pressure by the side wall of the chamber. 2. The honeycomb was not helpful for attaining uniform air flow in case that the air flow profile at the bottom of the vertical duct is serverely different from the ideal one. 3. Even though considerable pressure drop was resulted from the screens installed within the vertical duct, the screens were helpful for attaining uniform air flow in the duct. 4. It is desirable for the test section to be located at the position that not only the air flow of the duct is not disturbed by the distorted back pressure in the plenum chamber, but also less boundary layer is developed.