• Bulletin of the Korean Mathematical Society
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• v.60 no.5
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• pp.1265-1280
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• 2023

The aim of this paper is to investigate Betchov-Da Rios equation by using null Cartan, pseudo null and partially null curve in Minkowski spacetime. Time derivative formulas of frame of s parameter null Cartan, pseudo null and partially null curve are examined, respectively. By using the obtained derivative formulas, new results are given about the solution of Betchov-Da Rios equation. The differential geometric properties of these solutions are obtained with respect to Lorentzian causal character of s parameter curve. For a solution of Betchov-Da Rios equation, it is seen that null Cartan s parameter curves are space curves in three-dimensional Minkowski space. Then all points of the soliton surface are flat points of the surface for null Cartan and partially null curve. Thus, it is seen from the results obtained that there is no surface corresponding to the solution of Betchov-Da Rios equation by using the pseudo null s parameter curve.

• Advances in biomechanics and applications
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• v.1 no.2
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• pp.127-141
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• 2014

A preliminary study of a new pulsatile pump that will work to a frequency greater than 1 Hz, is presented. The fluid-structure interaction between a Newtonian blood flow and a piston drive that moves with periodic speed is simulated. The mechanism is of double effect and has four valves, two at the input flow and two at the output flow; the valves are simulated with specified velocity of closing and reopening. The simulation is made with finite elements software named COMSOL Multiphysics 3.3 to resolve the flow in a preliminary planar configuration. The geometry is 2D to determine areas of high speeds and high shear stresses that can cause hemolysis and platelet aggregation. The opening and closing valves are modelled by solid structure interacting with flow, the rhythmic opening and closing are synchronized with the piston harmonic movement. The boundary conditions at the input and output areas are only normal traction with reference pressure. On the other hand, the fluid structure interactions are manifested due to the non-slip boundary conditions over the piston moving surfaces, moving valve contours and fix pump walls. The non-physiologic frequency pulsatile pump, from the viewpoint of fluid flow analysis, is predicted feasible and with characteristic of low hemolysis and low thrombogenesis, because the stress tension and resident time are smaller than the limit and the vortices are destroyed for the periodic flow.

• Microbiology and Biotechnology Letters
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• v.48 no.2
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• pp.193-204
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• 2020

Sixteen acetic acid bacteria (AAB) were isolated from blueberries and citric fruits of the Salto Grande region (Concordia, Entre Rios, Argentina) using enrichment techniques and plate isolation. Enrichment broths containing ethanol and acetic acid enabled maximum AAB recovery, since these components promote their growth. Biochemical tests allowed classification of the bacteria at genus level. PCR-RFLP of the 16S rRNA and PCR-RFLP of the 16S-23S rRNA intergenic spacer allowed further classification at the species level; this required treatment of the amplified products of 16S and 16S-23S ITS ribosomal genes with the following restriction enzymes: AluI, RsaI, HaeIII, MspI, TaqI, CfoI, and Tru9I. C7, C8, A80, A160, and A180 isolates were identified as Gluconobacter frateurii; C1, C2, C3, C4, C5, C6, A70, and A210 isolates as Acetobacter pasteurianus; A50 and A140 isolates as Acetobacter tropicalis; and C9 isolate as Acetobacter syzygii. The bacteria identified by 16S rRNA PCR-RFLP were validated by 16S-23S PCR-RFLP; however, the C1 isolate showed different restriction patterns during identification and validation. Partial sequencing of the 16S gene resolved the discrepancy.

• Journal of the Optical Society of Korea
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• v.15 no.3
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• pp.252-263
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• 2011

In this work, for the first time, the quality of restoration in wide-field microscopy images after deconvolution was analyzed as a function of different Point Spread Functions using one deconvolution method, on a specimen of known size and on a biological specimen. The empirical Point Spread Function determination can significantly depend on the numerical aperture, refractive index of the embedding medium, refractive index of the immersion oil and cover slip thickness. The influence of all of these factors is shown in the same article and using the same microscope. We have found that the best deconvolution results are obtained when the empirical PSF utilized is obtained under the same conditions as the specimen. We also demonstrated that it is very important to quantitatively check the process' outcome using several quality indicators: Full-Width at Half-Maximum, Contrast-to-Noise Ratio, Signal-to-Noise Ratio and a Tenengrad-based function. We detected a significant improvement when using an indicator to measure the focus of the whole stack. Therefore, to qualitatively determinate the best deconvolved image between different conditions, one approach that we are pursuing is to use Tenengrad-based function indicators in images obtained using a wide-field microscope.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.665-668
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• 2017

임베디드 소프트웨어의 개발은 실제 어플리케이션이 수행되는 대상 시스템이 아닌 호스트 시스템에서 개발되기 때문에 개발 중 테스팅을 수행하기 어렵다. 또한 대상 시스템에서 어플리케이션이 실행될 때 결함 또는 오류가 발견되면 이를 재현하기 어렵다. 이러한 문제를 해결하기 위한 기존의 연구로는 RTOS 시뮬레이터를 사용하거나 모니터링 시스템을 추가하여 임베디드 소프트웨어의 동작을 확인한다. 하지만 RTOS 시뮬레이터는 기능 테스트만 가능하고 실직적인 시간 추정이 불가능하다. 또한 임베디드 소프트웨어에 모니터링 시스템을 추가하게 되면 어플리케이션의 동작에 영향을 주기 때문에 실시간 시스템의 제약 조건을 확인하기 어렵다. 따라서 본 논문에서는 임베디드 소프트웨어의 RIOS 기반 어플리케이션 구조를 제안하여 호스트 시스템에서 대상 시스템의 테스팅과 모니터링이 가능함을 보인다.

• Bulletin of the Korean Mathematical Society
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• v.42 no.1
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• pp.75-85
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• 2005

In this paper, the visco-Da-Rios equation; (0.1) ($$\frac{{\partial}{\gamma}}{{\partial}t}=\frac{{\partial}{\gamma}}{{\partial}s}{\bigwedge}\frac{D}{ds}\frac{{\partial}{\gamma}}{{\partial}s}+{\nu}\frac{{\partial}{\gamma}}{{\partial}s}$$) is investigated on 3-dimensional complete orientable Riemannian manifolds. The global existence of solution is discussed by trans-forming (0.1) into a cubic nonlinear Schrodinger equation for complete orient able Riemannian 3-manifolds of constant curvature.

• Toxicological Research
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• v.11 no.2
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• pp.223-227
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• 1995

This study was conducted to investigate the metallothionein (MT) induction by Lonicerae rios in cadmium chloride intoxication. The results were as follows: Generally, detoxication effects by Lonicerae fios extract increased to the increase of extract concentrations. When 90 mg/kg dosage of Lonicerae fios extract was administered, it showed the highest antitoxic effects in metallothionein induction. From the above results, Lonicerae rios extract increased metallothionein concentration and decreased the toxicity of cadmium in liver.

• Toxicological Research
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• v.12 no.1
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• pp.41-46
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• 1996

This study was performed to investigate the antitoxic component in methanol fraction of Lonicerae fios. The results were as follows: 1. When a 500 ppm of water soluble fraction of Lonicerae flos was administered, it showed the highest antitoxic effect. 2. Generally, detoxication effects by methanol fraction of Lonicerae fios increased. When the ethyl acetate soluble fraction of Lonicerae rios was administered, it exhibited the highest antitoxic effect against the toxicity of cadmium in Liver. 3. The combined administration of cadmium and methanol fraction of Lonicerae rios significantly increased metallothionein in liver compared to administration of cadmium only. This phenomenon was more remarkable when the ethyl acetate soluble fraction of Lonicerae fios was administered with cadmium chloride.

• Journal of Mechanical Science and Technology
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• v.16 no.11
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• pp.1367-1378
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• 2002

This paper investigates observability properties of strapdown INS aided by a GPS antenna array. The motivation to consider a GPS antenna array is that the lever-arms between the GPS antennas and IMU play an important role in the estimation of vehicle attitude and biases of IMU. It is shown that time-invariant INS error models are observable with measurements from at least three GPS antennas. It is also shown that time-varying error models are instantaneously observable with measurements from three antennas. Numerical simulation results are given to show the effectiveness of multiple GPS antennas on estimating vehicle attitude and biases of IMU when IMU has considerable magnitude of biases.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.7
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• pp.1185-1192
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• 2003

Governing parameters for determination of the location of crack initiation and direction of crack initiation were investigated by performing fretting fatigue tests and analysis on Al 2024-T351. Fatigue tests were carried out using biaxial fatigue machine. It was shown that the dominant fatigue crack tended to initiate at the outer edge of one of the four bridge pads, growing at an angle beneath a pad, before turning perpendicular to the orientation of the axial load. Distribution of stresses generated during fretting fatigue loading along the interface was calculated by elastic FE simulation. It can be known that the location of crack initiation can be predicted by using the maximum tangential stress range. Futhermore, the crack initiation direction can also be predicted by a maximum tangential stress range.