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Search Results: 1 - 10 of 51429 matches for " Won Jin Lee "
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Generic Lightlike Submanifolds of an Indefinite Cosymplectic Manifold
Dae Ho Jin,Jae Won Lee
Mathematical Problems in Engineering , 2011, DOI: 10.1155/2011/610986
Abstract: Lightlike geometry has its applications in general relativity, particularly in black hole theory. Indeed, it is known that lightlike hypersurfaces are examples of physical models of Killing horizons in general relativity (Galloway, 2007). In this paper, we introduce the definition of generic lightlike submanifolds of an indefinite cosymplectic manifold. We investigate new results on a class of generic lightlike submanifolds of an indefinite cosymplectic manifold .
A Basic Inequality for the Tanaka-Webster Connection
Dae Ho Jin,Jae Won Lee
Journal of Applied Mathematics , 2012, DOI: 10.1155/2012/231416
Abstract: For submanifolds tangent to the structure vector field in Sasakian space forms, we establish a Chen's basic inequality between the main intrinsic invariants of the submanifold (namely, its pseudosectional curvature and pseudosectional curvature on one side) and the main extrinsic invariant (namely, squared pseudomean curvature on the other side) with respect to the Tanaka-Webster connection. Moreover, involving the pseudo-Ricci curvature and the squared pseudo-mean curvature, we obtain a basic inequality for submanifolds of a Sasakian space form tangent to the structure vector field in terms of the Tanaka-Webster connection.
Constancy of $φ-$holomorphic scetional curvature in generalized $g.f.f-$manifolds
Jae Won Lee,Dae Ho Jin
Mathematics , 2011,
Abstract: Tanno [6] provided an algebraic characterization in an almost Hermitian manifold to reduce to a space of constant holomorphic sectional curvature, which he later extended for the Sasakian manifolds as well. In this present paper, we generalize the same characterization in generalized $g.f.f-$manifolds.
The kernel of $Burau(4) \otimes Z_p$ is all pseudo-Anosov
Sang Jin Lee,Won Taek Song
Mathematics , 2004,
Abstract: We show that the kernel of $Burau(4) \otimes Z_p$, the reduced Burau representation with coefficients in $Z_p$ of the 4-braid group $B_4$, consists only of pseudo-Anosov braids.
Diffraction by Dielectric-Loaded Multiple Slits in a Conducting Plane: TM Case
Dong-Jin Lee;Soo-Ji Lee;Won-Seok Lee;Jong-Won Yu
PIER , 2012, DOI: 10.2528/PIER12081311
Abstract: A new and exact series solution for the scattering and coupling problems by dielectric-loaded multiple slits in a perfectly conducting screen is presented. The case of normal incidence and TM polarization is considered. The scattered and transmitted elds are represented in terms of an in nite series of radial modes. By applying the appropriate boundary conditions, the coecients of scattered and transmitted elds are obtained and some numerical results are given.
The clinical utility of tuberculin skin test and interferon-γ release assay in the diagnosis of active tuberculosis among young adults: a prospective observational study
Ji Eun Lee, Hee-Jin Kim, Sei Won Lee
BMC Infectious Diseases , 2011, DOI: 10.1186/1471-2334-11-96
Abstract: We prospectively enrolled 166 young participants 20-29 years of age with suspected active TB in a military hospital of South Korea. The TST and QFT-IT were performed for all participants.Of the 143 patients included in the analysis, active TB was diagnosed in 100 (69.9%). There were 141 male patients, none of whom had immunosuppressive disease. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of TST were 94% (95% CI, 87-98%), 88% (95% CI, 74-96%), 95% (95% CI, 88-98%), and 86% (95% CI, 72-94%), respectively. The sensitivity, specificity, PPV, and NPV of the QFT-IT were 93% (95% CI, 86-97%), 95% (95% CI, 81-99%), 98% (95% CI, 92-99%), and 84% (95% CI, 69-93%), respectively. No significant differences were found between the TST and QFT-IT in any statistic.Both the TST and QFT-IT showed high sensitivity and specificity in differentiating active TB from other diseases. The diagnostic accuracy of these two tests did not differ significantly when applied to this clinical population of young, immunocompetent adults in whom neonatal BCG vaccination was common, there was no history of previous TB and in whom suspicion of TB was high.ClinicalTrials.gov: NCT00982969Tuberculosis (TB) is an important public health problem worldwide. In 2007, there were 9.27 million cases of TB, and 1.3 million deaths occurred among HIV-negative TB cases [1]. South Korea has an intermediate TB burden; the incidence of new cases is 90 per 100 000 people per year despite an intensive effort for disease control [2]. A prompt and accurate diagnosis is critical for effective control and management of TB, but conventional diagnostic methods have their limitations. Completion of mycobacteria culture takes 3-8 weeks on solid medium and 7-21 days in liquid medium [3,4]. The sensitivity of acid-fast bacilli (AFB) smears is low [3]. The polymerase chain reaction test is often used for rapid microbiological diagnosis of TB, but its sensitivity for smear-negat
Magnetization dynamics driven by angle-dependent spin-orbit spin transfer torque
Seo-Won Lee,Kyung-Jin Lee
Physics , 2015,
Abstract: Spin-orbit spin transfer torque allows an efficient control of magnetization by an in-plane current. Recent experiments found that the spin-orbit torque has strong dependence on the magnetization angle [Garello et al., Nature Nanotechnol. 8, 587 (2013); Qiu et al., Sci. Rep. 4, 4491 (2014)]. We theoretically investigate magnetization switching and domain wall motion in a perpendicularly magnetized layer, induced by angle-dependent spin-orbit torque. We obtain analytic expressions of the switching current and domain wall velocity, in agreement with numerical results. Based on the expressions, we find that the spin-orbit torque increasing with the polar angle of magnetization is beneficial for both switching and domain wall motion. Our result will serve as a guideline to design and interpret switching and domain wall experiments based on spin-orbit torque.
Investigation on the insecticidal limonoid content of commercial biopesticides and neem extract using solid phase extraction  [PDF]
Ji-Won Lee, Cho-Long Jin, Ki Chang Jang, Geun-Hyoung Choi, Hee-Dong Lee, Jin Hyo Kim
Journal of Agricultural Chemistry and Environment (JACEN) , 2013, DOI: 10.4236/jacen.2013.24012
Abstract: Neem extract is an alternative insecticide for organic farming and is an allowed component for commercial biopesticide in Korea. However, crop protection properties are not consistent in commercial products. In this report, quantitative analysis of commercial biopesticides for the four insecticidal limonoids of neem extract-azadirachtin A, azadirachtin B, deacetylsalannin and salannin, was conducted through solid phase extraction method with lipophilic-hydrophilic balanced material. The recoveries of the four limonoids ranged from 80.5% to 105%, and their limit of quantitation ranged from 0.028 mg/L to 0.356 mg/L. On the five imported neem extracts, the total contents of the four bioactive limonoids extracted were from 321 mg/L to 5810 mg/L, but there were big variations in the relative composition of the limonoids. The total limonoidal concentrations in 23 commercial bio-pesticides made from neem showed from below LOQ to 7190 mg/L with significant differences in the relative composition. These differences determine the biopesticide’s efficacy on pests, therefore, tracking the active ingredients is necessary for the quality control of commercial bio-pesticides.
Comparison of Depth Dose Distributions Using Cerenkov Fiber-Optic Dosimeter and Monte Carlo Simulation for HDR Brachytherapy  [PDF]
Sang Hun Shin, Young Beom Song, Mingeon Kim, Hye Jin Kim, Wook Jae Yoo, Kyoung Won Jang, Bongsoo Lee
Journal of Applied Mathematics and Physics (JAMP) , 2016, DOI: 10.4236/jamp.2016.48157
In this study, we fabricated a Cerenkov fiber-optic dosimeter (CFOD) without any scintillator to measure Cerenkov radiation signals owing to gamma-rays. The relative depth dose (RDD) distributions of Ir-192 HDR brachytherapy source were obtained by using the CFOD based on a subtraction method and the RDD curve was compared with the simulation result of Monte Carlo N-particle extended transport code (MCNPX). Finally, we demonstrated that the CFOD can be used to measure real-time dose information for HDR brachytherapy.
Two New Marine Sponges of the Genus Haliclona (Haplosclerida: Chalinidae) from Korea
Dong Won Kang,Kyung Jin Lee,Chung Ja Sim
Animal Systematics, Evolution and Diversity , 2013, DOI: http://dx.doi.org/10.5635/ased.2013.29.1.51
Abstract: Two new marine sponges, Haliclona (Haliclona) tonggumiensis n. sp. and H. (Reniera) sinyeoensis n. sp., in the family Chalinidae were collected from Ulleungdo Island and Gageodo Island, Korea from 2007 to 2009. Haliclona (Haliclona) tonggumiensis n. sp. is similar to H. (H.) simulans (Johnston, 1842) in shape, but the former differs in its ectosomal skeleton structure and spicules’ shape and size. The ectosomal skeleton of H. (H.) tonggumiensis n. sp. is absent, but that of H. (H.) simulans is very regularly arranged, and has tangential reticulation with oxea. The spicule shape of H. (H.) tonggumiensis n. sp. is slender, but that of H. (H.) simulans is short and cigar-shape. The new species have two sizes of oxea, but H. (H.) simulans has one size of oxea. Haliclona (Reniera) sinyeoensis n. sp. resembles H. (R.) tubifera (George and Wilson, 1919) in the growth form and choanosomal skeleton structure. However, the new species has two kinds of oxea in size, but H. (R.) tubifera has only one size.
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