• International Journal of Contents
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• 제11권2호
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• pp.9-14
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• 2015

We propose a new distance measure between 2-dimensional points to provide a total order for an entire point set and to reflect the correct geometric meaning of the naturalness of the point ordering. In general, there is no total order for 2-dimensional point sets, so curve reconstruction algorithms do not solve the self-intersection problem because the distance used in the previous methods is the Euclidean distance. A natural distance based on Brownian motion was previously proposed to solve the self-intersection problem. However, the distance reflects the wrong geometric meaning of the naturalness. In this paper, we correct the disadvantage of the natural distance by introducing a polar-natural distance, and we also propose a new curve reconstruction algorithm that is based on the polar-natural distance. Our experiments show that the new distance adequately reflects the correct geometric meaning, so non-simple curve reconstruction can be solved.

• Journal of applied mathematics & informatics
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• 제41권5호
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• pp.1085-1102
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• 2023

In this study the magneto hydrodynamic (MHD) micro polar fluid flow of a viscous incompressible fluid past a porous medium in the presence of chemical reaction is considered. This work is devoted to investigate the Soret effect and Electromagnetic radiation effect and analyze analytically. In the energy equation the applied magnetic field strength and in the concentration equation the Soret effect are incorporated. The basic PDE (partial differential equations) are reduced to ODE (ordinary differential equations) using non dimensional variables. Then the analytical solution of the dimensionless equations are found using perturbation technique. The features of the fluid flow parameters are analyzed, discussed and explained graphically. The graphical solutions are found using MATLAB R2019b. Skin friction coefficient at the wall, Couple stress coefficient at the plate and the local surface heat flux are also thoroughly examined. Overall, this study sheds light on the complex interplay between physical parameters in the behavior of MHD micro-polar fluid past a porous medium in the presence of chemical reaction.

• Natural Product Sciences
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• 제15권1호
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• pp.1-7
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• 2009

This study was performed to investigate the cell growth inhibitory effect of tissue cultured root of wild Panax ginseng C.A. Mayer (tcwPG). The human stomach carcinoma cell line, MKN 74, was incubated with 70% EtOH extract of tcwPG or Panax ginseng C.A. Mayer (PG) for 24 hrs. tcwPG inhibited cell growth at a concentration of $250{\mu}g/ml$. However, Panax ginseng extract did not inhibit cell growth at the same concentration. We also tested the ethyl acetate and $H_2O$ fractions of tcwPG. The inhibitory effect of the ethyl acetate fraction on cell proliferation in MKN 74 cells was more potent than that of the crude extract, and the inhibitory effect of the $H_2O$ fraction was less than that of the ethyl acetate fraction. When we separated tcwPG into polar and non-polar saponin fractions and then measured cell growth inhibition, the non-polar saponin in tcwPG exhibited cytotoxicity. To compare the effects of tcwPG on various cancer cell lines, we measured cytotoxicity in MKN 74 (stomach cancer cell line), SW 620 (colon cancer cell line) and PC 3 (prostate cancer cell line). All three cell lines showed cell growth inhibition, and the cell growth inhibitory effects were not quite different in the various cell lines. The non-polar saponins of tcwPG arrested PC 3 cells at G1-phase as did Panax ginseng.

• 한국포장학회지
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• 제10권1호
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• pp.7-14
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• 2004

Migration behavior of selected solvents and food samples showed differences of the chemical structures and polarities, the food samples which have similar polar expresses more higher affinity than different polar degrees. Water which is polar has a highest partitioning coefficient values on polar isopropanol, and oil which is nonpolar has highest partitioning value on non-polar toluene. The increasing order of partitioning values was accord with increasing water contents in food samples. It is showed that the wheat flour with 13.2% moisture content has the highest partitioning coefficient values on the isopropanol with -OH. Kp value of sugar showed remarkable lower partitioning coefficient values than other food samples due to high degree crystallinity. This phenomenon can be predictable with ${\delta}$ values, because order of partitioning coefficient values which comes out through the experiment and the sequence of Hildebrand solubility parameter value difference between food sample and printing ink solvent correspond almost. This Hildebrand solubility parameter value can be easily applied to the food package industry because the effect of food-safety can be considered without passing through complicated steps by using this method.

• Journal of Astronomy and Space Sciences
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• 제27권2호
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• pp.97-106
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• 2010

To prepare for a Korean lunar orbiter mission, a precise lunar orbit propagator; Yonsei precise lunar orbit propagator (YSPLOP) is developed. In the propagator, accelerations due to the Moon's non-spherical gravity, the point masses of the Earth, Moon, Sun, Mars, Jupiter and also, solar radiation pressures can be included. The developed propagator's performance is validated and propagation errors between YSPOLP and STK/Astrogator are found to have about maximum 4-m, in along-track direction during 30 days (Earth's time) of propagation. Also, it is found that the lifetime of a lunar polar orbiter is strongly affected by the different degrees and orders of the lunar gravity model, by a third body's gravitational attractions (especially the Earth), and by the different orbital inclinations. The reliable lifetime of circular lunar polar orbiter at about 100 km altitude is estimated to have about 160 days (Earth's time). However, to estimate the reasonable lifetime of circular lunar polar orbiter at about 100 km altitude, it is strongly recommended to consider at least $50\;{\times}\;50$ degrees and orders of the lunar gravity field. The results provided in this paper are expected to make further progress in the design fields of Korea's lunar orbiter missions.

• Journal of Astronomy and Space Sciences
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• 제35권2호
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• pp.93-103
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• 2018

Non-specular, vertically upward transit, fast-moving radar echoes are observed in the summer polar upper mesosphere near 90 km using 52 MHz VHF radar at Esrange, Sweden. By resolving maximum echo power movement, the unusual meteor trails propagate vertically upward with taking horizontal displacements at an initial speed of 10 km/s exponentially decreasing with increasing height from 85-89 km, lasting for 3.5 sec. Another upward transit is observed as following a downward transit echo target in about ~1 sec, lasting over 5 sec. The upward motion cannot be explained with the dynamics of penetrating meteors or by atmospheric dynamics. The observation proposes that secondary produced plasma jets occurring from meteor trail are possibly responsible for upward fast moving echoes. The long-lasting (3-5 sec), ascending meteor trails at speeds of a few $10^4m/s$ are distinctive from any previous occurrences of meteors or upper atmospheric electrical discharges in the aspect of long-lasting upward/downward motions. This result possibly suggests a new type of meteor-trail leader discharge occurring in the summer polar upper mesosphere and lower thermosphere.

• 접착 및 계면
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• 제12권1호
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• pp.11-15
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• 2011

본 연구에서는 저독성 용제에 용해도가 있는 열가소성 폴리우레탄(TPU, Thermoplastic Polyurethane)을 합성하고 폴리우레탄 합성시 사용되는 사슬연장제 및 NCO/OH 비에 따른 물성 변화를 알아보았다. 또한 합성된 열가소성 폴리우레탄을 이용하여 난접착재질용 저독성 프라이머를 제조하고 접착특성을 알아보고자 하였다. TPU 합성시 r(NCO/OH) = 2.0 이상인 경우에는 폴리올 및 이소시아네이트의 종류에 관계없이, 저독성 용제에 용해도가 저하되는 결과를 나타냈으며, non polar한 구조를 가지고 있는 접착증진제보다는 polar한 구조를 가지고 있는 접착증진제의 접착력이 우수하게 나타났다.

• Food Science and Biotechnology
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• 제15권3호
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• pp.482-484
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• 2006

The antioxidant activity of Bacillus polyfermenticus SCD was studied by partially purified culture extracts using various methods: ammonium sulfate precipitation, adsorption to Diaion HP-20 columns using polar solvents, and extraction using non-polar solvents. The 1,1-diphenyl-2-picyrylhydrazyl (DPPH) radical scavenging activity of these partially purified fractions was then investigated. The precipitate isolated using 75%-saturated ammonium sulfate was shown to contain about 77.2% DPPH radical scavenging activity. Using the Diaion HP-20 resin adsorption method, the fraction obtained using 60% ethanol and 60% methanol possessed 76.7 and 89.5% DPPH radical scavenging activity, respectively. Fractions obtained by extracting with the non-polar solvents 80 mg/mL chloroform, 80 mg/mL n-hexane, 80 mg/mL ethyl acetate, and 80 mg/mL butanol contained 68.4, 75.0, 70.7, and 87.5% DPPH radical scavenging activity, respectively. Further study is needed to characterize the antioxidant substance(s) released by B. polyfermenticus SCD cultures.

• 한국수정란이식학회지
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• 제21권3호
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• pp.169-175
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• 2006

본 연구에서 돼지 난포란에서 채취된 난모세포들을 체외 성숙 후 세포 손상이 없이 성숙 난모세포의 발생능을 알아낼 수 있는 마커로 극체의 방출이 효과적으로 활용될 수 있는지를 알아보았다. 난모세포를 48시간 성숙 배양 후 극체의 방출 유무를 검사하고, 핵염색하여 염색체의 형태를 검사하였다. 확인된 난모세포들을 $16{\sim}18$시간 추가 배양한 후 7% ethanol로 활성화시키고 $5{\mu}g/ml$ cytochalasin B에 5시간 노출 후 NCSU23 배양액으로 7일간 배양하였다. 극체 방출율은 반복에 따라 $9.9{\sim}52.4%$, 퇴행율은 $21.4{\sim}61.8%$로 변이가 크게 나타났다(p<0.01). 극체를 방출한 난모세포의 핵상은 모두 극체와 19개의 염색체를 가진 제 2 감수분열 중기 핵상을 보여주었으며, 극체를 방출하지 못한 난모세포의 핵상은 핵이 팽화된 상태인 핵형이 39.1%, PCC 형태의 핵상이 19.6%, MI 형태의 핵상이 10.9%, MII이지만 극체가 관찰되지 않거나 매우 작은 상태인 경우가 13%, 핵이 응축된 형태인 경우가 6.5%, 핵이 없는 경우가 8.7%로 나타났다. 퇴행란으로 판단한 난모세포들은 핵염색을 한 결과 역시 세포질 상태가 정상적이지 못한 염색 상태를 보여주었다. 극체 방출 유무를 확인하지 않고 활성화 처리 후 배양하였을 때 분할율은 45.0%, 배반포기까지 발달율은 11.3%였으나, 극체 방출란만을 모아서 활성화처리를 하였을 때 분할율은 94.2%, 배반포기까지 발달율은 42.5%로 급격하게 향상되었다. 이상의 결과로 퇴행란과 극체 미방출란을 제거하고 실험에 활용한다면 배양 효과를 확인하거나 배아 생명 공학에 활용할 때 좀더 유리 할 것으로 사료된다.

• Journal of Communications and Networks
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• 제17권4호
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• pp.328-338
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• 2015

Three areas of ongoing research in channel coding are surveyed, and recent developments are presented in each area: Spatially coupled low-density parity-check (LDPC) codes, nonbinary LDPC codes, and polar coding.