• Journal of Technologic Dentistry
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• v.38 no.2
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• pp.79-84
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• 2016

Purpose: The aim of this study was to make nanomesh on the surface of titanium by potentiostatic technique which was done at the suitable potential level. Methods: In order to find the suitable potential level, use a $25^{\circ}C$ NaCl, NaOH and NH4F solution of 1 M and 5 M as supporting electrolyte, working electrode(positive potential) was contact to the titanium specimen and counter electrode(negative potential) was contact to the Pt substrate. At the transpassive potential which was observed by potentiostatic technique, potentiostatic technique was done for 2hours. Results: As a result, 1 M NaOH solution was suitable as a supporting electrolyte, potentiostatic technique used a $25^{\circ}C$ NaOH solution of 1 M for 2hours, nanomesh was formed. Conclusion: The potentiostatic technique was used $25^{\circ}C$ NaOH solution of 1 M and 5 M as supporting electrolyte for 2hours. Nanomesh was built more uniform and fine in 1 M NaOH solution than 5 M NaOH solution.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.2 no.1
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• pp.1-14
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• 2007

In this paper we investigated the organization of regional business incubation center itself and that of companies in center and scrutinized the problems and obstacles to take self-supporting administration for both of center and companies in it. We classified the companies operating inside the center into four types according to the formation of organizations analyzed them, and proposed some solutions to enhance their operating abilities to obtain elf- supporting administration.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.205-208
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• 2005

Fabrication of large scaled mirror for the telescope application is the most challenging technology in recent year. Sophisticate technologies and know-how in fabrication and measurement are required to overcome the technological obstacles. KRISS(Korea Research Institute for Standards and Science) is now developing a large scaled mirror fabrication facility and KARI(Korea Aerospace Research Institute) is supporting the development. High precision interferometric test is required during the grinding and polishing of mirror to identify the surface profile precisely. The required fabrication accuracy of the mirror surface profile is $\lambda$/50 ms($\sim$10 nm for visible wave length). Thus the measurement accuracy should be far less than 10 m. To get this requirement, it is necessary to provide vibration free environment for the interferometer system and mirror under test. Thus the vibration responses on the mirror supporting table due to external vibration should be minimized by using a special isolation system. And the responses on the top of the tower, which hold the interferometer during test, should be minimized simultaneously. In this paper, we propose the concept design of vibration suppression system for the KRISS mirror fabrication facility.

• Geomechanics and Engineering
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• v.33 no.5
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• pp.439-451
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• 2023

The construction of shield tunnelling in urban sites is facing serious risks from complex and changeable underground conditions. Construction problems in the sand-clay mixed ground have been more reported in recent decades for its poor control of soil loss in tunnel face, ground settlement and supporting pressure. Since the limitations of observation methods, the conventional physical modelling experiments normally simplify the tunnelling to a plane strain situation whose results are not reliable in mixed ground cases which exhibit more complicated responses. We propose a new method for the study of the mixed ground tunnel through which mixed lays are simulated with transparent soil surrogates exhibiting different mechanical properties. An experimental framework for the transparent soil modelling of the mixed ground tunnel was established incorporated with the self-developed digital image correlation system (PhotoInfor). To understand better the response of face stability, ground deformation, settlement and supporting phenomenon to tunnelling excavation in the sand-clay mixed ground, a series of case studies were carried out comparing the results from cases subjected to different buried depths and mixed phenomenon. The results indicate that the deformation mode, settlement and supporting phenomenon vary with the mixed phenomenon and buried depth. Moreover, a stratigraphic effect exists that the ground movement around mixed face reveals a notable difference.

• Journal of the Ergonomics Society of Korea
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• v.35 no.6
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• pp.503-517
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• 2016

Objective: The aim of this study was to evaluate the effectiveness of 3 dimensional contoured pillow through analyzing contact pressure and to suggest its design guidelines through analyzing the posture of head and neck area. Background: The quality of sleep is a very important factor closely related with human's health. To improve the quality of sleep, the verification of design factors affecting the posture of the head and neck is needed, and a pillow design that can induce proper posture is required. Method: This study measured the contact pressures of the two reference groups (bead and cotton pillows) as a method to evaluate the design effectiveness of the contoured pillow. This study proposed 3-dimensional design guidelines by drawing anthropometry (head length) affecting cervical curvature angle (CCA) through the measurement of the participants' cervical curvature angles. Results: In the design effectiveness evaluation, the contact pressure of cervical region was higher than that of a reference group (cotton pillow), and contract area increased, and contract pressure decreased in the shape distributing the occipital region's body pressure. This study proposed pillow's cervical supporting height by percentile of a head length [head length (%tile) (cervical supporting height) affecting the posture of the head and neck: 14.6cm (5%tile) (6.2cm), 15.5cm (25%tile) (6.7cm), 16.4cm (50%tile) (7.1cm), and 19.3cm (75%tile) (8.9cm)]. Conclusion: This study confirmed the contoured pillow's design effectiveness maintaining cervical angle comfortable to sleep with the shape supporting the cervical vertebrae and by reducing the contact load of the occipital region. Also, this study proposed pillow design guidelines based on the 3-dimensional contoured pillow design effectiveness, through which the study laid the foundation for pillow design in a systematic method. Application: The results of this study are expected to be utilized as the basis data by which the optimum pillow type and pillow design according to main percentile can be standardized.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.35 no.3
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• pp.57-66
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• 2023

In order to understand the economic feasibility of an offshore wind farm, this paper analyzed the differences in LCOE (levelized cost of energy) according to the support type and construction method of the substructure in terms of LCOE and sensitivity analysis was conducted according to the main components of LCOE. As for the site to be studied, the Southwest Offshore Wind Farm was selected, and the capital expenditures were calculated according to the size of the offshore wind farm and the installation unit. As a result of the sensitivity analysis, major components showed high sensitivity to availability, turbine related cost, weighted average cost of capital and balance of system related cost. Moreover, the post-piling jacket method, which was representatively applied to the substructure of the offshore wind farm in Korea, was selected as a basic plan to calculate the capital expenditures, and then the capital expenditures of the pre-piling jacket method and the tripod method were calculated and compared. As a result of analyzing the LCOE, it was confirmed that the pre-piling jacket method of the supporting structure lowers the LCOE and improves economic feasibility as the installation number of turbines increases.

• Proceedings of the Korean Information Science Society Conference
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• 2010.11a
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• pp.151-152
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• 2010

• Analytical Science and Technology
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• v.11 no.4
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• pp.260-265
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• 1998

Spherical, ${\mu}m$-sized particles of barium titanyl oxalate were prepared by thermal decomposition of dimethyl oxalate in acidic barium and titanium solutions. Precipitation was carried out in the presence of several supporting anions. Spherical particles having a specific type of particle size distribution. i.e., unimodal or bimodal distribution, with mean size in the range of $0.2{\sim}3{\mu}m$, were formed depending on the supporting anions, oxalate ion generation rate and aging time. Particles of barium titanyl oxalate settled on the bottom of the beaker at the aging time of 120 min grew to the critical monosize of about $1.5{\sim}3{\mu}m$. XRD spectra and chemical analyses of barium titanate showed that barium titanyl oxalate with high qualities could be synthesized by choosing chloride ion as a supporting anion and increasing the reaction temperatures.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.4
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• pp.117-124
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• 2015

As recent developing computing environments, service is provided without time or place's limitation, and it is constituted dynamically. Above all, in terms of education supporting system, there is need to conceive user's information and provide optimal service as to right with applying context awareness under Ubiquitous computing environment. It should have groundwork based on user location and time. It is requires service providing based on user location under the condition of class to offer appropriate service with the context. In addition, context information providing technology is needed to offer right education support service in the class, where are different context information. Hence, in this research it is suggested education supporting system to provide context-based for instructor. The framework of this system has a foundation within previous work about Multi-agent based Distributed Framework. To examine implementation of context-based education supporting system in Ubiquitous computing environments suggested by this report, arranging system can fit information relates to instructor's location for service applying in the class.

• Nuclear Engineering and Technology
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• v.28 no.1
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• pp.17-26
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• 1996

The in-reactor fuel rod support conditions against the fretting wear-induced damage can be evaluated by residual spacer grid spring deflection or rod-to-grid gap. In order to evaluate the impact of fuel design parameters on the fretting wear-induced damage, a simulation methodology of the in-reactor fuel rod supporting conditions as a function of burnup has been developed and implemented in the GRIDFORCE program. The simulation methodology takes into account cladding creep rate, initial spring deflection, initial spring force, and spring force relaxation rate as the key fuel design parameters affecting the in-reactor fuel rod supporting conditions. Based on the parametric studies on these key parameters, it is found that the initial spring deflection, the spring force relaxation rate and cladding creepdown rate are in the order of the impact on the in-reactor fuel rod supporting conditions. Application of this simulation methodology to the fretting wear-induced failure experienced in a commercial plant indicates that this methodology can be utilized as an effective tool in evaluating the capability of newly developed cladding materials and/or new spacer grid designs against the fretting wear-induced damage.