• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.2
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• pp.159-165
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• 2016

Recently, active efforts are being made for future Si CMOS technology by various researches on emerging devices and materials. Capability of low power consumption becomes increasingly important criterion for advanced logic devices in extending the Si CMOS. In this work, a junctionless field-effect transistor (JLFET) with ultra-thin poly-Si (UTP) channel is designed aiming the sub-10-nm technology for low-power (LP) applications. A comparative study by device simulations has been performed for the devices with crystalline and polycrystalline Si channels, respectively, in order to demonstrate that the difference in their performances becomes smaller and eventually disappears as the 10-nm regime is reached. The UTP JLFET would be one of the strongest candidates for advanced logic technology, with various virtues of high-speed operation, low power consumption, and low-thermal-budget process integration.

• Korean Journal of Computational Design and Engineering
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• v.21 no.1
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• pp.9-19
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• 2016

Applying human engineering simulation to analyzing work capability and movements of operators during manufacturing is highly demanded. However, difficulty in modeling digital human required for simulation makes engineers to be reluctant to utilize human simulation for their tasks. This paper addresses such problem on human engineering simulation by developing the technology to automatize human modeling with multiple Kinects at different depths. The Kinects enable us to acquire the movements of digital human which are essential data for implementing human engineering simulation. In this paper, we present a system for modeling automation of digital human. Especially, the system provides a way of generating the digital model of workers' movement and position using multiple Kinects which cannot be generated by single Kinect. Lastly, we verify the effects of the developed system in terms of modeling time and accuracy by applying the system to four different scenarios. In conclusion, the proposed system makes it possible to generate the digital human model easily and reduce costs and time for human engineering simulation.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.3
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• pp.265-276
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• 2020

The objective of this study is to develop education programs for cultivating smart aquaculture experts through a education demand survey of industries, high school students, university (graduate) students and field workers. The industry demand analysis was conducted as an in-depth interview on representives from seven companies. Education demand surveys were conducted on 96 students and field workers in the Jeonnam region. Results on the demand survey were analyzed using frequency analysis and cross-analysis. The company representatives responded that they want to participated in internship and retraining programs to proactively secure manpowers with convergence capabilities about smart aquaculture. Seven companies preferred manpowers with basic competencies on ICT (Information and Communications Technologies) or aquaculture. The most respondents in the demand survey want to participate in the education program for experience on advanced technology, self-development and enhancement of work capability. On the other hand, some respondents said that the education is time-consuming and that the education program does not fit their level. Thus, the education program should be developed in a way to minimize the spatial and temporal limitations of education targets and to improve understanding of non-majors by reflecting the demands of human resources in the industrial field.

• Journal of Soil and Groundwater Environment
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• v.22 no.5
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• pp.128-134
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• 2017

This work presents the adsorption capability of green tea and ginseng leaves to adsorb heavy metals such as Cd(II), Cu(II), and Pb(II) in aqueous solution. FT-IR analysis indicates the presence of oxygen containing functional groups (carboxyl groups) in two kinds of leaves. High pH condition was favorable to the adsorption of heavy metal ions due to the enhanced electrostatic attraction and the precipitation reaction of metal ions. The adsorption of Cd(II), Cu(II), and Pb(II) reached equilibrium within 10 min, achieving high removal efficiencies of 80.3-97.5%. The adsorption kinetics data of heavy metal ions were fitted well with the pseudo-second-order kinetic model. The maximum adsorption amounts of Cd(II), Cu(II), and Pb(II) ions were 8, 3.5, and 15 mg/g, respectively, in the initial concentration range from 0.15 to 0.75 mM. Based on the fitting data obtained from isotherm models, heavy metal adsorption by green tea and ginseng leaves could occur via multi-layer sorption.

• Structural Engineering and Mechanics
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• v.66 no.5
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• pp.557-568
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• 2018

An investigation is made in the present work on the post-buckling and geometrically nonlinear behaviors of moderately thick perfect and imperfect rectangular plates made-up of functionally graded materials. Spectral collocation approach based on Legendre basis functions is developed to analyze the functionally graded plates while they are subjected to end-shortening strain. The material properties in this study are varied through the thickness according to the simple power law distribution. The fundamental equations for moderately thick rectangular plates are derived using first order shear deformation plate theory and taking into account both geometric nonlinearity and initial geometric imperfections. In the current study, the domain of interest is discretized with Legendre-Gauss-Lobatto nodes. The equilibrium equations will be obtained by discretizing the Von-Karman's equilibrium equations and also boundary conditions with finite Legendre basis functions that are substituted into the displacement fields. Due to effect of geometric nonlinearity, the final set of equilibrium equations is nonlinear and therefore the quadratic extrapolation technique is used to solve them. Since the number of equations in this approach will always be more than the number of unknown coefficients, the least squares technique will be used. Finally, the effects of boundary conditions, initial geometric imperfection and material properties are investigated and discussed to demonstrate the validity and capability of proposed method.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.359.1-359.1
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• 2016

The electromagnetic (EM) properties of media, such as propagation, focusing and scattering, strongly rely on the electric permittivity and the magnetic permeability of media. Recently, artificially-created metamaterials (MMs) composed of periodically-arranged unit cells with tailored electric permittivity and magnetic permeability have drawn wide interest due to their capability of adjusting the EM response. MM absorbers using the conventional sandwich structures usually have very high absorption at a certain frequency, and the absorption properties of MMs can be adjusted simply by changing the geometrical parameters of unit cell. In this work, we suggested an incident-angle-independent broadband perfect absorber based on resistive layers. We analyze the absorption mechanism based on the impedance matching with the free space and the distribution of surface currents at specific frequencies. From the simulation, the absorption was expected to be higher than 96% in 1.4-6.0 GHz. The corresponding experimental absorption was found to be higher than 96% in 1.4-4.0 GHz, and the absorption turned out to be slightly lower than 96% in 4.0-6.0 GHz owing to the irregularity in the thickness of resistive layers.

• Smart Structures and Systems
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• v.16 no.5
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• pp.835-851
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• 2015

This paper presents theoretical and experimental evaluation of the structural health monitoring (SHM) capability of piezoelectric wafer active sensors (PWAS) at elevated temperatures. This is important because the technologies for structural sensing and monitoring need to account for the thermal effect and compensate for it. Permanently installed PWAS transducers have been One of the extensively employed sensor technologies for in-situ continuous SHM. In this paper, the electro-mechanical impedance spectroscopy (EMIS) method has been utilized as a dynamic descriptor of PWAS behavior and as a high frequency standing wave local modal technique. Another SHM technology utilizes PWAS as far-field transient transducers to excite and detect guided waves propagating through the structure. This paper first presents how the EMIS method is used to qualify and quantify circular PWAS resonators in an increasing temperature environment up to 230 deg C. The piezoelectric material degradation with temperature was investigated and trends of variation with temperature were deduced from experimental measurements. These effects were introduced in a wave propagation simulation software called Wave Form Revealer (WFR). The thermal effects on the substrate material were also considered. Thus, the changes in the propagating guided wave signal at various temperatures could be simulated. The paper ends with summary and conclusions followed by suggestions for further work.

• Journal of The Korean Association of Information Education
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• v.9 no.2
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• pp.211-219
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• 2005

Several problems occur in reading education in a elementary school. They are the lack of considering the difference of student's capability and diagnosing their reading ability, the review activity focusing on only text and the discontinuation between school and home. Our system is designed and implemented to support leveled reading education using multimedia technology. We can diagnose the student's reading ability exactly and promptly and introduce suitable books considering their ability, and work the proper review activities with this system. It can help the students to interest their reading.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.220-222
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• 2004

Feasibility of BaO-ZnO-$B_2O_3$ (BZB) based glass system in the light of dielectric and thermal expansion properties are reported in the literature. Effects of addition of various types of ceramic fillers to the BZB-based glass on the thermochemical stability and mechanical properties were investigated in the present work. The studied filler-glass system demonstrated a capability to host various types of ceramic fillers to form thermochemically stable microcomposites at the processing temperature suitable for PDP systems. At the same time, mechanical strength of the filler-glass composites was much improved as compared to the glass itself These observations brighten the feasibility of the Pb-free BZB-based glass system as a host to employ various types of crystalline ceramic fillers so that it can be applied to barrier rib material in plasma display panels.

• Journal of Environmental Science International
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• v.2 no.4
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• pp.347-356
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• 1993

The three natural zeolites collected in Yungil-gun, Kyungsangbuk-do, Korea, were analyzed by means of chemical wet methods and X-ray diffraction. The results indicated that the primary species of those zeolites were clinoptilolite mixed with heulandite, feldspar, montmorillonite, and quartz. These zeolites were chemically treated with NaOH, $\textrm{Ca(OH)}_2$, and HCl solution and their differences were also studied with X-ray diffraction method. The capabilities of removing $Cs^+$ and Sr^{2+}$ ions with chemically untreated zeolites, chemically treated zeolites, and also with synthetic zeolites were compared. The effect of other cations in removing Sr^{2+}$ ions was also studied. The experimental results showed that$Cs^+$ and Sr^{2+}$ ions could be removed up to 98% and 95% respectively out of 5 ppm with chemically untrearted natural zeolites. The treatment of 0.02N-$\textrm{Ca(OH)}_2$ and that of 2N-NaOH were most effective In removing $Cs^+$ and Sr^{2+}$ ions, respectively. It was found that the mountaintop of Sangjung 1-dong natural zeolite treated with 2N-NaOH was most efficient in removing Sr^{2+}$ ions mixed with other cations, compared with any other chemically treated and untreated natural zeolites in this work.