• Korean Chemical Engineering Research
• /
• v.45 no.5
• /
• pp.487-492
• /
• 2007

Using the selective host-guest inclusion of $G_2$[naphthalene disulfonate], the structural isomers of 1,2-dibromobenzene and 1,3-dibromobenzene were separated. As such, 1,3-dibromobenzene was selectively included as guest into the host framework in mixture isomers over 30% fraction of 1,3- dibromobenzene ($X_{1,3-DBB}=0.3$) whereas 1,2-dibromobenzene as guest was selective to the inclusion below $X_{1,3-DBB}=0.3$. This was due to the selectivity of host framework toward the guest molecules playing a role of template to the host framework. From the powder pattern XRD of inclusion compounds crystallized in pure isomer and mixture solutions, the template roles of guest molecules to the host framework were confirmed. Using the DSC, it was found that the more energy was required to release 1,3-dibromobenzene of guest from the host framework than 1,2-dibromobenzene due to the higher thermal stability. The thermal stability of the $G_2NDS$-1,3-dibromobenzene inclusion compound was consistent with the high selectivity of 1,3- dibromobenzene to the host framework in broad range of fraction in the isomer mixture

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.10
• /
• pp.4648-4659
• /
• 2011

Korea experienced rapid urbanization due to high growth of economy. As people left the country and gathered in the city, the size of city has been expanded, resulting in unbalanced development of the land. In addition, it appears in diverse aspects from nationwide phenomenon to the local development in each city unit. In particular, it even tends to become social problems in the metropolitan cities. As a solution for it, this study conducts theoretical consideration on sustainability in the aspect of balanced urban development and suggests measures through analysis on Siheung-city. The result is as follows. First of all, comprehensive approach is required based on sustainability. It is required to derive balanced city development by expanding it to the social, cultural and economic aspects. Second, integrated management policy is required for the original city along with new development. It should be considered together with diverse social and physical aspects. Third, approach from the aspect of city planning is required through consideration on flat city expansion and connection with city space structural. Fourth, in order to foster balanced urban development, it is needed to grope for solutions for imbalanced urban development through the participation of diverse groups such as local residents, private enterprisers, and the non-profit civic groups of the local community along with the mediation among persons interested. And continuous support of administrative authorities should be obtained to create such environment.

• Cartoon and Animation Studies
• /
• s.48
• /
• pp.1-22
• /
• 2017

Independent short animation was the expression method for young animation creators through creative and progressive representation. Since the birth of animation, independent short animation has become a driving force for qualitative development and diversification of animation. This has brought many works to the world that emphasize experimentation and challenges in the history of animation and in countries that have the rich animation resources such as France, Japan, and Canada, they recognize its importance and supports young creators in order to maintain the value of it. However, Korean animations are evaluated the quality of works by the popularity of the children, moreover, companies that focus on developing and selling products, including toys, rather than animation works themselves and public awareness that accepts them are formed throughout the Korean animation industry. Because of these points, Korean animation creators can not express the creative vision for the future and philosophical awareness of the problem and they are trapped in commercial animation markets. In order to re-leap and expand the Korean animation industry, which has reached the saturation level with infant animation, it is necessary to reestablish the value of independent short animations with challenging and experimental characteristics and requires the creative environment and support system for the diversity of Korean animation industries, including the achieving commercial goals through good planning, story development and technological innovation. For this purpose, this paper analyzes the current state of production, screening, distribution, and government support of independent short animation in Korea, and explores the structural problems and solutions.

• Korean Journal of Materials Research
• /
• v.22 no.5
• /
• pp.220-226
• /
• 2012

Pure zirconia and $x$ mol% calcia partially stabilized zirconia ($x$ = 1.5, 3, and 8) nanopowders were synthesized by hydrothermal method with various reaction temperatures for 24 hrs. The precipitated precursor of pure zirconia and $x$ mol% calcia doped zirconia was prepared by adding $NH_4OH$ to starting solutions; resulting sample was then put into an autoclave reactor. The optimal experimental conditions, such as reaction temperatures and times and amounts of stabilizer CaO, were carefully studied. The synthesized $ZrO_2$ and $x$ mol% CaO-$ZrO_2$ ($x$ = 1.5, 3, and 8) powders were characterized by XRD, SEM, TG-DTA, and Raman spectroscopy. When the hydrothermal temperature was as low as $160^{\circ}C$, pure $ZrO_2$ and $x$ mol% CaO-$ZrO_2$ ($x$ = 1.5 and 3) powders were identified as a mixture of monoclinic and tetragonal phases. However, a stable tetragonal phase of zirconia was observed in the 8 mol% calcia doped zirconia nanopowder at hydrothermal temperature above $160^{\circ}C$. To observe the phase transition, the 3 mol% CaO-$ZrO_2$ and 8 mol% CaO-$ZrO_2$ nanopowders were heat treated from 600 to $1000^{\circ}C$ for 2h. The 3 mol% CaO-$ZrO_2$ heat treated at above $1000^{\circ}C$ was found to undergo a complete phase transition from mixture phase to monoclinic phase. However, the 8 mol% calcia doped zirconia appeared in the stable tetragonal phase after heat treatment. The result of this study therefore should be considered as the preparation of 8 mol% CaO-$ZrO_2$ nanopowders via the hydrothermal method.

• Journal of the Korea Institute of Building Construction
• /
• v.11 no.4
• /
• pp.333-344
• /
• 2011

The recent expansion in the number of housing construction projects has been accompanied by substantial improvements in construction quality, which can be attributed to the development of new construction technologies and materials. In apartment complex construction projects, numerous mechanization technologies have been adopted as part of the floor plastering process to counter increasing difficulties in securing labor and the pressing need to reduce lead time, but these have also triggered setbacks such as additional costs or loss of time to fix cracks in or loosening of floor. Cracks developing in the floor of an apartment housing unit, in terms of materials in use, are the products of a complex combination of material makeup, construction workmanship, concrete curing and the protection method. Controlling such elements from the perspective of materials in use may ensure partial success in reducing cracks, but fall short of eliminating them completely. Any attempt to prevent cracks from developing in the first place requires systematic analysis as to their potential causes and viable solutions to reduce them. On this backdrop, this paper aims to provide an analysis of potential causes of cracks found in floor plastering, and consider the mechanism of a crack stop-bar as a fundamental safeguard against them.

• Journal of the Korean GEO-environmental Society
• /
• v.15 no.7
• /
• pp.23-30
• /
• 2014

This paper deals with the characteristics of deformation of the underground corrugated steel plate culverts constructed in the areas where the minimum depth of within 1.5 m soil cover is not secured in the bottom of highways. The underground corrugated steel plate culverts at shallow depth are often designed and constructed with the consideration of the minimum depth of soil cover according to the design standards, which was made in order to minimize any deformation. Additionally, if under unfavorable conditions, slabs are set up for stress relaxation to disperse and minimize the weight of loads transferred to the corrugated steel plate culverts. Nevertheless, if the underground corrugated steel plate culverts are built in areas where the minimum depth of soil cover inevitably cannot be secured, there may occur some deformation. In this paper, a research was carried out to identify the characteristics of deformation in areas where the minimum depth of soil cover is not secured. The result shows that there existed the deterioration of pavement and in its smoothness around the corners of slabs for stress relaxation. To this end, this paper studied the structural stability of the underground corrugated steel plate culverts established in the areas with no minimum depth of soil cover secured, with the consideration of causes and solutions of pavement deterioration.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.3 no.2
• /
• pp.87-96
• /
• 1999

To analyze the dynamic behavior of structure, direct integration and mode superposition may be utilized in time domain analysis. As finite number of frequencies can give relatively exact solutions, mode superposition is preferable in analyzing structural behavior. In non-linear analysis, however, mode superposition is seldom used since time-varying element stiffness changes stiffness matrix, and the change of stiffness matrix leads to the change of essential constants - natural frequencies and mode shapes. In spite of these difficulties, there are some attempts to adopt mode superposition because of low cost compared to direct integration, but the result is not satisfactory. In this paper, a method using mode superposition in non-linear analysis is presented by separating local element stiffness from global stiffness matrix with the difference between linear and non-linear restoring forces to the external force vectors included. Moreover, the hysteresis model changing with the relative deformation in each floor makes it possible to analyze non-linear behavior of structure. The proposed algorithm is applied to shear beam model and the maximum displacement is compared with the result using direct integration method.

• Food Science and Preservation
• /
• v.11 no.4
• /
• pp.496-502
• /
• 2004

Purified acorn starch was obtained from alkali precipitation method. Acorn amylose and acorn amylopectin were fractionated from purified acorn starch by butanol improvement method. Gel permeation chromatography (GPC) was used to measure molecular weight distribution of acorn starch, acorn amylose, acorn amylopectin and corn starch, corn amylose, corn amylopectin. GPC measurement diagrams were obtained by each retention time. And then, we used DMSO and DMF as solvent, pullulan as standard material. We calculated the Number-average molar mass (Mn), Weight-average molar mass (Mw) and polydispersity from molecular weight distribution of each sample. As a result of estimating molecular weight using GPC, Mw of amylose has small value than Mw of amylopectin. From this fact, the molecular structural aspects of amylose and amylopectin were predicted and it was in good agrement with the tendency of polydispersity by GPC. The polydispersity of starch had big value than amylose and amylopectin, from this result, it might be known that the range of molecular weight appeared broad by heterogeneous properties of two components. The viscosity of purified acorn starch, amylose, amylopectin seperated from acorn starch, was decreased by increasing the shear rate and raising the temperature exponentially. Acorn starch solutions exhibited pseudoplastic power law fluid behavior.

• Journal of Gifted/Talented Education
• /
• v.26 no.1
• /
• pp.211-230
• /
• 2016

The study aimed to investigate the characteristics of algebraic thinking of the mathematically gifted students and search for how to teach algebraic thinking. Research subjects in this study included 93 students who applied for a science gifted education center affiliated with a university in 2015 and previously experienced gifted education. Students' responses on an algebraic item of a creative thinking test in mathematics, which was given as screening process for admission were collected as data. A framework of algebraic thinking factors were extracted from literature review and utilized for data analysis. It was found that students showed difficulty in quantitative reasoning between two quantities and tendency to find solutions regarding equations as problem solving tools. In this process, students tended to concentrate variables on unknown place holders and to had difficulty understanding various meanings of variables. Some of students generated errors about algebraic concepts. In conclusions, it is recommended that functional thinking including such as generalizing and reasoning the relation among changing quantities is extended, procedural as well as structural aspects of algebraic expressions are emphasized, various situations to learn variables are given, and activities constructing variables on their own are strengthened for improving gifted students' learning and teaching algebra.

• Journal of the Korean institute of surface engineering
• /
• v.49 no.6
• /
• pp.513-520
• /
• 2016

Many surface protection methods have been developed to apply to constructional steels which have been used under severe corrosive environments. One of these methods, hot dip galvanizing is being widely used to the numerous constructional steels such as a guard rail of high way, various types of structural steel for manufacturing ship and for some other industrial fields etc.. Recently, the cost of zinc is getting higher and higher, thus, it is considered that improvement of hot dip galvanizing process to reduce the cost of production should be developed possibly. In this study, additives such as acid cleaning solution, $NH_4OH$, $Al(OH)_3$ and $H_2O_2$ were added to flux solution, and omission of water washing treatment after acid cleaning was investigated with some types of flux solutions added with some additives mentioned above. The decrement of pH by adding the acid cleaning solution could be controlled due to neutralization reaction with addition of $NH_4OH$. The flux solution added with both $NH_4OH$ and $Al(OH)_3$ exhibited nearly the same color and pH value as those of orignal flux solution with no added, and the sample dipped to the flux solution which was added with additives mentioned above indicated a relatively good corrosion resistance compared to other samples. However, the flux solution added with $NH_4OH$, $Al(OH)_3$ and $H_2O_2$ exhibited a different color, sediment and a bad corrosion resistance. Consequently, it is considered that omission of water washing treatment may be able to perform by adding optimum additives to the original flux solution.