• Bulletin of the Korean Chemical Society
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• v.10 no.6
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• pp.551-554
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• 1989

Quadrupole coupling constants of $^{63}$CU in the high $T_c$ superconductor $YBa_2Cu_3O_7_{-x}$, as determined by NQR or NMR studies, are compared with the values for representative Cu(Ⅱ) complexes determined by analyzing the forbidden lines in their EPR spectra. It is shown that the two NQR lines at 22 and 31 MHz correpsond to the quadrupole coupling constants of a square planar Cu(Ⅱ) complex and a square pyramidal Cu(Ⅱ) complex, respectively.t This result is in agreement with the assignment of these lines to Cu(1) and Cu(2) sites in YBCO based on the NMR spectra of oriented single crystals.

• Journal of the Semiconductor & Display Technology
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• v.20 no.1
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• pp.54-58
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• 2021

The RGO with controllable oxygen functional groups is a novel material as the active layer of resistive switching memory through a reduction process. We designed a nanoscale conductive channel induced by local oxygen ion diffusion in an Au / RGO+GQD / Al resistive switching memory structure. A strong electric field was locally generated around the Al metal channel generated in BIL, and the local formation of a direct conductive low-dimensional channel in the complex RGO graphene quantum dot region was confirmed. The resistive memory design of the complex RGO graphene quantum dot structure can be applied as an effective structure for charge transport, and it has been shown that the resistive switching mechanism based on the movement of oxygen and metal ions is a fundamental alternative to understanding and application of next-generation intelligent semiconductor systems.

• Advances in nano research
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• v.13 no.6
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• pp.599-617
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• 2022

In the present research, for the first time, the vibrational as well as buckling characteristics of a three-layered curved nanobeam including a core made of functionally graded (FG) material and two layers of smart material-piezo-magneto-electric-resting on a Winkler Pasternak elastic foundation are examined. The displacement field for the nanobeam is chosen via Timoshenko beam theory. Also, the size dependency is taken into account by using nonlocal strain gradient theory, aka NSGT. Then, by employing Hamilton's principle, energy procedure, the governing equations together with the boundary conditions are achieved. The solution procedure is a numerical solution called generalized differential quadrature method, or GDQM. The accuracy and reliability of the formulation alongside solution method is examined by using other published articles. Lastly, the parameter which can alter and affect the buckling or vocational behavior of the curved nanobeam is investigated in details.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.4
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• pp.413-418
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• 2020

It is necessary to manage the prediction accuracy of the machine learning model to prevent the decrease in the performance of the grid network condition prediction model due to overfitting of the initial training data and to continuously utilize the prediction model in the field by maintaining the prediction accuracy. In this paper, we propose an automation technique for maintaining the performance of the model, which increases the accuracy and reliability of the prediction model by considering the characteristics of the power grid state data that constantly changes due to various factors, and enables quality maintenance at a level applicable to the field. The proposed technique modeled a series of tasks for maintaining the performance of the power grid condition prediction model through the application of the workflow management technology in the form of a workflow, and then automated it to make the work more efficient. In addition, the reliability of the performance result is secured by evaluating the performance of the prediction model taking into account both the degree of change in the statistical characteristics of the data and the level of generalization of the prediction, which has not been attempted in the existing technology. Through this, the accuracy of the prediction model is maintained at a certain level, and further new development of predictive models with excellent performance is possible. As a result, the proposed technique not only solves the problem of performance degradation of the predictive model, but also improves the field utilization of the condition prediction model in a complex power grid system.

• The Journal of Society for e-Business Studies
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• v.9 no.1
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• pp.209-220
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• 2004

If protocol has fast operations and short key length, it can be efficient user authentication protocol. Lenstra and Verheul proposed XTR. XTR have short key length and fast computing speed. Therefore, this can be used usefully in complex arithmetic. In this paper, to design efficient user authentication protocol we used a subgroup of Galois Field to problem domain. Proposed protocol does not use GF(p/sup 6/) that is existent finite field, and uses GF(p²) that is subgroup and solves problem. XTR-ElGamal based user authentication protocol reduced bit number that is required when exchange key by doing with upside. Also, proposed protocol provided easy calculation and execution by reducing required overhead when calculate. In this paper, we designed authentication protocol with y/sub i/ = g/sup b.p/sup 2(i-1)//ㆍv mol q, 1(equation omitted) 3 that is required to do user authentication.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1004-1009
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• 2003

Electroosmotic flow induced by an applied electrostatic potential field in microchannel is analyzed in this study. The electroosmotic flow is an alternative to pressure driven flow in microchannels, but the usage has been limited to the simple cases. In this study, We analyze electroosmotic flow driven by inhomogeneous surface charge on the channel wall. The surface charge varies along a direction perpendicular to the electric field in order to generate the electroosmotic flow. A numerical results substantiate the highly efficient mixing performance. It is highly the beneficial to fabrication process since only straight microchannel rather than complex geometry is enough to yield efficient mixing.

• Applied Microscopy
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• v.46 no.3
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• pp.127-133
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• 2016

Atom probe tomography is a time-of-flight mass spectrometry-based microanalysis technique based on the field evaporation of surface atoms of a tip-shaped specimen under an extremely high surface electric field. It enables three-dimensional characterization for deeper understanding of chemical nature in conductive materials at nanometer/atomic level, because of its high depth and spatial resolutions and ppm-level sensitivity. Indeed, the technique has been widely used to investigate the elemental partitioning in the complex microstructures, the segregation of solute atoms to the boundaries, interfaces, and dislocations as well as following of the evolution of precipitation staring from the early stage of cluster formation to the final stage of the equilibrium precipitates. The current review article aims at giving a comment to first atom probe users regarding the limitation of the techniques, providing a brief perspective on how we correctly interprets atom probe data for targeted applications.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.272-273
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• 2001

We demonstrate the first separation of neutral molecules using optical forces. Unlike laser atomic cooling or optical tweezers, optical separation technique requires the manipulation of only one component of the molecular motion. Thus the mixtures can be separated, in principle, with less complex schemes. When an Intense nonresonant laser beam is focused onto a beam of molecules, the interaction between the laser electric field and the induced dipole moment of a molecule invokes a mechanical force on the molecule proportional to the field gradient and the molecular polarizability ($\alpha$) to mass (m) ratio $\alpha$/m. (omitted)

• The Journal of Korea Robotics Society
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• v.18 no.1
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• pp.88-92
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• 2023

Lithium-ion batteries are actively used in various industrial sites such as field robots, drones, and electric vehicles due to their high energy efficiency, light weight, long life span, and low self-discharge rate. When using a lithium-ion battery in a field, it is important to accurately estimate the SoC (State of Charge) of batteries to prevent damage. In recent years, SoC estimation using data-based artificial neural networks has been in the spotlight, but it has been difficult to deploy in the embedded board environment at the actual site because the computation is heavy and complex. To solve this problem, neural network lightening technologies such as network pruning have recently attracted attention. When pruning a neural network, the performance varies depending on which layer and how much pruning is performed. In this paper, we introduce an optimized pruning technique by improving the existing pruning method, and perform a comparative experiment to analyze the results.

• Bulletin of the Korean Chemical Society
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• v.14 no.5
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• pp.561-567
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• 1993

The twelve macrocycle (L) complexes of cadmium(II) nitrate have been synthesized: $CdL(NO_3)_2$. All the complexes have been indentified by elemental analysis, electric conductivity measurements, IR and NMR spectroscopic techniques. The molar electric conductivities of the complexes in water and acetonitrile solvent were in the range of 236.8-296.1 $cm^2{\cdot}mol^{-1}{\cdot}ohm^{-1}$ at 25$^{\circ}$C. The characteristic peaks of macrocycles affected from Cd(II) were shifted to lower frequencies as compared with uncomplexed macrocycles. A complex with 1,4,8,11-tetrakis(methylacetato)-1,4,8,11-tetraaza cyclodecane (L4) exhibited two characteristic bands such as strong stretching (1646 $cm^{-1})$, and weaker symmetric stretching band (1384 $cm^{-1})$. NMR studies indicated that all nitrogen donor atoms of macrocycles have greater affinity to cadmium(II) metal ion than do the oxygen atoms. The $^{13}$C-resonance lines of methylene groups neighboring the donor atom such as N and S were shifted to a direction of high magnetic field and the order of chemical shifts were $L_1 < L_2 < L_3 < L_6 < L_4$. Also the chemical shifts values were larger than those of methylene groups bridgeheaded in side-armed groups. This result seems due to not only the strong interaction of Cd(Ⅱ) with nitrogen donors according to the HSAB theory, but weak interaction of Cd(Ⅱ) and COO- ions or sulfur which is enhanced by the flexible methylene spacing group in side-armed groups. Thus, each additional gem-methyl pairs of L_3, L_4\;and\; L_6$ macrocycles relative to $L_1, L_2,\;and\;L_5$ leads to an large enhancement in Cd(II) affinity. ^{13}C$-NMR spectrum of the complex with $L_{12}$ (1,5,9,13-tetracyclothiacyclohexadecane-3,11-diol) reveals the presence of two sets of three resonance lines, and intensities of the each resonance line have the ratio of 1 : 2 : 2. This molecular conformation is predicted as structure of tetragonal complex to be formed by coordinating two sulfur atoms and the other two sulfur atoms which is affected by OH-groups.