• International Journal of Aeronautical and Space Sciences
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• v.16 no.3
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• pp.347-359
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• 2015

A method of describing the rovibrational energy transitions and coupled chemical reactions in the direct simulation Monte Carlo (DSMC) calculations is constructed for $H(^2S)+H_2(X^1{\Sigma}_g)$ and $He(^1S)+H_2(X^1{\Sigma}_g)$. First, the state-specific total cross sections for each rovibrational states are proposed to describe the state-resolved elastic collisions. The state-resolved method is constructed to describe the rotational-vibrational-translational (RVT) energy transitions and coupled chemical reactions by these state-specific total cross sections and the rovibrational state-to-state transition cross sections of bound-bound and bound-free transitions. The RVT energy transitions and coupled chemical reactions are calculated by the state-resolved method in various heat bath conditions without relying on a macroscopic properties and phenomenological models of the DSMC. In nonequilibrium heat bath calculations, the state-resolved method are validated with those of the master equation calculations and the existing shock-tube experimental data. In bound-free transitions, the parameters of the existing chemical reaction models of the DSMC are proposed through the calibrations in the thermochemical nonequilibrium conditions. When the bound-free transition component of the state-resolved method is replaced by the existing chemical reaction models, the same agreement can be obtained except total collision energy model.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.82-82
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• 2012

Angle-resolved photoemission spectroscopy (ARPES) is a powerful tool to investigate the electronic structure of a single-crystalline solid. After the development of a two-dimensional electron detector, it became a basic experimental method in solid state physics comparable to other powerful tools such as x-ray and neutron scatterings. In this tutorial, I talk briefly on the basic principle of ARPES and its recent and future direction of development.

• Bulletin of the Korean Chemical Society
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• v.14 no.1
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• pp.72-78
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• 1993

The application of time-resolved laser induced fluorescence spectroscopy (TRLIF) to the complexation studies of Eu(III) and Cm(III) with humic substances is described. Using this method, three different spectroscopic characteristics(excitation spectra, emission spectra, and lifetimes) of these aquo ions and their complexes can be directly measured. By observing shifts in the wavelength and changes in the lifetime and intensities of the fluorescence emission, the information on the complexation behavior of humic substances with these trivalent metal cations in an aqueous solution, as well as energy transfer mechanisms, can be obtained. In addition, this method allows precise spectroscopic quantification of the complexation processes at very low concentrations of both components.

• Journal of Korea Multimedia Society
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• v.25 no.1
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• pp.124-134
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• 2022

Based on existing research, the psychological state of Chinese students has become a very significant issue that needs to be resolved. In addition to paying attention to the daily life and study of Chinese students, the psychological problems of Chinese students are also worthy of attention. At the same time, if the existing psychological problems are not resolved in time, serious consequences may result. Based on the ART(Attention Restoration Theory) theory, this article uses VR (Virtual Reality) content as a medium, uses 3D modeling software to build a healing scene that helps Chinese students improve their psychological and emotional state, and presents it in a VR device. To achieve the purpose of improving the psychological and emotional state of Chinese students. According to experimental tests, the VR recovery scene constructed by this method can help improve the psychological mood of Chinese international students who already have subliminal depression. The results of independent sample T-tests after data analysis experiments show that after the intervention of the experiment, the depression of the experimental group is significantly improved compared to the control group. It is proved that the method in this study is effective for the mentality and emotion of Chinese international students who have subliminal depression. There is a significant improvement effect.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.349-352
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• 2006

The plastic deformation of polycrystalline materials is induced by changes of the microstructure when the loading is beyond the critical state of stress. Constitutive models for the crystal plasticity have the common objective which relates microscopic single crystals in the crystallographic texture to the macroscopic continuum point. In this paper, a new consistent tangent stiffness for the anisotropic elasto-viscoplastic analysis of polycrystalline deformation is developed, which can be used in the finite element analysis for the slip-dominated large deformation of polycrystalline materials. In order to calculate the consistent tangent stiffness, the state function is defined based on the consistency condition between the elastic and plastic stress. The rate of shearing increment($\Delta{\gamma}^{\alpha}$) is calculated with satisfying the consistency condition. The consistency condition becomes zero when the trial resolved shear stress($\tau^{{\alpha}^*}$) becomes resolved shear stress($\tau^{\alpha}$) at every step. Iterative method is utilized to calculate the rate of shearing increment based on the implicit backward Euler method. The consistent tangent stiffness can be formulated by differentiating the rate of shearing increment with total strain increment after the instant rate of shearing increment converges. The proposed tangent stiffness is applied to the ABAQUS/Standard by implementing in the ABAQUS/UMAT.

• Journal of Photoscience
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• v.3 no.3
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• pp.141-145
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• 1996

The heat generated by nonradiative decay dynamics induces thermal lens effect. From such an effect, photodynamic properties of solutions can be investigated with two-color pulsed thermal lens experiments which have the time resolution of down to nanoseconds. In this study, using nanosecond two-color thermal lens method, we investigated the triplet state of benzophenone and the singlet oxygen state dynamics in various oxygen concentration solvents. The measured triplet state lifetimes, singlet oxygen relaxation times and singlet oxygen formation quantum yields are in good agreement with the reference values. From these parameters the existence of the triplet exciplex formation between benzophenone and benzene is proved, and it is also suggested that the relaxations of triplet states of benzophenone undergo coupled dynamics with some of singlet oxygens in oxygen-rich conditions.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.9
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• pp.1432-1440
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• 1997

The flexibility as well as the stiffness is required to perform mechanical function of a structure such as compliant mechanisms, which can be applied to MEMS(Micro-Electro-Mechanical Systems), flexible manufacturing devices, and design for no assembly. In this paper, the optimal design problem to achieve both structural flexibility and stiffness is formulated using multi-objective function, and the optimization problem is resolved by using Finite Element Method(FEM) and Sequential Linear Programming(SLP). Design examples of compliant mechanisms are presented to validate the design method.

• Journal of Advanced Research in Ocean Engineering
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• v.4 no.1
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• pp.16-24
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• 2018

This paper addresses the heading control of an offshore floating storage and regasification unit (FSRU) using a resolved motion and acceleration control (RMAC) algorithm. A turret moored vessel tends to have the slewing motion. This slewing motion may cause a considerable decrease in working time in loading and unloading operation because the sloshing in the LNG containment tank might happen and/or the collision between FSRU and LNGC may take place. In order to deal with the downtime problem due to this slewing motion, a heading control system for the turret moored FSRU is developed, and a series of model tests with azimuth thrusters on the FSRU is conducted. A Kalman filter is applied to estimate the low-frequency motion of the vessel. The RMAC algorithm is employed as a primary heading control method and modified I-controller is introduced to reduce the steady-state errors of the heading of the FSRU.

• BMB Reports
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• v.55 no.3
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• pp.113-124
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• 2022

Single-cell RNA sequencing (scRNA-seq) has greatly advanced our understanding of cellular heterogeneity by profiling individual cell transcriptomes. However, cell dissociation from the tissue structure causes a loss of spatial information, which hinders the identification of intercellular communication networks and global transcriptional patterns present in the tissue architecture. To overcome this limitation, novel transcriptomic platforms that preserve spatial information have been actively developed. Significant achievements in imaging technologies have enabled in situ targeted transcriptomic profiling in single cells at single-molecule resolution. In addition, technologies based on mRNA capture followed by sequencing have made possible profiling of the genome-wide transcriptome at the 55-100 ㎛ resolution. Unfortunately, neither imaging-based technology nor capture-based method elucidates a complete picture of the spatial transcriptome in a tissue. Therefore, addressing specific biological questions requires balancing experimental throughput and spatial resolution, mandating the efforts to develop computational algorithms that are pivotal to circumvent technology-specific limitations. In this review, we focus on the current state-of-the-art spatially resolved transcriptomic technologies, describe their applications in a variety of biological domains, and explore recent discoveries demonstrating their enormous potential in biomedical research. We further highlight novel integrative computational methodologies with other data modalities that provide a framework to derive biological insight into heterogeneous and complex tissue organization.

• Structural Engineering and Mechanics
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• v.52 no.1
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• pp.205-220
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• 2014

This paper is concerned with the modification of multidisciplinary feasible formulation for MDO problems using the integrated coupled approximate models. A drawback of conventional MDFs is the numerical difficulty in decomposing the design variables and deriving the coupled equations of state. To overcome such a drawback of conventional methods, the coupling in analysis and design is resolved by approximating the state variables in each discipline by the response surface method and by modifying the optimization formulation using the corresponding integrated coupled approximate models. The validity, reliability and effectiveness of the proposed method are illustrated and verified through two optimization problems, a mathematical MDF problem and the multidisciplinary optimum design of suspension unit of wheeled armored vehicle.