• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.71-74
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• 2005

The increasement in the floor hight may be one of the most significant problem in the use of precast concrete double slab in the multi-story buildings. The modified double-tees including duct space at the ends of slab were considered in this study. The length and thickness of nib of modified double tee was increased to receive the uniform reaction from rectangular beam, while the original PCI dapped one to receive the point load from inverted tee beam to the leg of double tee. Shear tests were performed on the ends of the modified double tees which were designed by strut-tie model. The modified double tees generally show more ductile flexural failure in the long thickened nib. It is concluded that they show superior failure patterns than that of original dapped one with shear failure.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.267-270
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• 2005

The section of double-tee is considered as one of the most efficient type for flexure. However, the depth of it is bigger then that of other slab systems. The story height of it is also increased because the duct space is required under the double tee in addition to their net depth. Thus, a new modified double-tees with the nib length of 1.58m was suggested in this study. The story height of this one is reduced up to 450mm by including duct space under the nib at the ends of slab. The four ends of the modified two single tees were designed by strut-tie models. Shear tests were performed on them to verify the safety. The ultimate shear strengths of non-prestressed two specimens were larger than the design shear strength by strut-tie models. They were failed in ductile with many distributed flexural crackings. However, the other prestressed two specimens showed much stiffer behaviors, less deflection. and strength than those of prestressed.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.5
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• pp.738-747
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• 1998

The purpose of this study was to compare the positional stability of removable dies using several dowel pin systems. The removable dies were made by using five dowel pin systems: single dowel pin(Group I), single dowel pin and prepared groove on the die base(Group II), two-single dowel pin(Group III), two separate parallel dowel pins with plastic sleeves(Group IV), double straight dowel pins with metal sleeve(Group V). Special aluminum mold was made for specimens, and the dies of specimens removed and replaced thirty times with universal testing machine. Horizontal and vertical shift of dies was measured by Olympus monocular scanning tunneling microscope(STM5). The results were as follows: 1. The vertical shift was larger than the horizontal shift in all the other groups except Group I. 2. Single dowel pin system(Group I) was the most unstable of five dowel pin systems. 3. Double dowel pin systems with steeve(group IV, V) were the most stable of five dowel pin systems. 4. This study indicates that excellent horizontal positional stability is attainable with use of additional groove on the die base or double dowel pin. and excellent vertical positional stability is attainable with use of sleeve.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.4
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• pp.440-451
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• 1998

An experimental study has been conducted to investigate solidification of NH$_{4}$CI-H$_{2}$0 mixtures inside a vertical rectangular enclosure. Solidification process is visualized by the shadowgraph method. Emphasis is placed on the effect of solidification parameters such as the aspect ratio, cooling wall temperature and initial composition. The aspect ratio shows a dominant effect on the number and developing time of the double diffusive layers which reveals the relative strength of solutal convection to thermal convection. Similar flow pattern is observed when the concentration difference between interdendritic liquid and the pure liquid which drives solutal convection is the same regardless of the different cooling wall temperature and initial concentration.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1542-1547
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• 2003

This paper represents the solar collector performance with type of an evacuate double glass, and a copper tube was installed in center of collector to get a solar thermal energy. The one module of solar collector and artificial sun were used in this experiment The distance between artificial sun and solar collector was fixed at 0.5m, and this experimental condition was focused on winter season. The experiments were carried out. three times for getting a accurate data and the heat amount of one module evacuate d solar collector was estimated at out. 48 kcal/hr.

• Journal of the Korean Society of Combustion
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• v.22 no.1
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• pp.1-7
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• 2017

This paper presents an experimental study on the effect of double injection strategies on combustion characteristics in a single-cylinder diesel engine. These studies are applied to the double injection strategies, such as $2^{nd}$ injection timing variations with fixed injection interval (8 degree) and variations of injection pressures with fixed injection timing and intervals. The injection quantity was 7 + 7 mg for double injections, and 14 mg for single injection. When the injection pressure was increased, the ignition delay was shortened, and the ISFC (indicated specific fuel consumption) was increased due to the fast termination of combustion by the shortened energizing duration. In addition, the retardation of injection timings toward TDC (top dead center) caused the reduction of ignition delay and the decrease of ISFC with the decrease of FMEP (friction mean effective pressure).

• Journal of Mechanical Science and Technology
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• v.15 no.1
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• pp.88-97
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• 2001

The present study numerically investigates the fuel-air mixing characteristics, flame structure, and pollutant emission inside a double-swirler combustor. A PSR(Perfectly Stirred Reactor) based microstructural model is employed to account for the effects of finite rate chemistry on the flame structure and NO formation. The turbulent combustion model is extended to nonadiabatic flame condition with radiation by introducing an enthalpy variable, and the radiative heat loss is calculated by a local, geometry-independent model. The effects of turbulent fluctuation are taken into account by the joint assumed PDFs. Numerical model is based on the non-orthogonal body-fitted coordinate system and the pressure/velocity coupling is handled by PISO algorithm in context with the finite volume formulation. The present PSR-based turbulent combustion model has been applied to analyze the highly intense turbulent nonpremixed flame field in the double swirler combustor. The detailed discussions were made for the flow structure, combustion effects on flow structure, flame structure, and emission characteristics in the highly intense turbulent swirling flame of the double swirler burner.

• Journal of Fashion Business
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• v.9 no.4
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• pp.127-144
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• 2005

The aim of this study is to find out the symbol of clothing decorations in Elsa Schiaparalli's design works and there are four major points due to the aim of this study. Firstly, a fantasy is represented through Surrealistic Arts which creates mysterious, secrete, and surprising spirits. In Surrealistic Arts, the fashion of schiaparelli demonstrates a fantasy spirit by using the methods like metaphor, transformation, and re-positioning. Secondly, In Surrealistic paintings, normally double image or different image from symbol immanent were expressed. However, Elsa Schiaparelli used double and multi-image decorations instead that has well-organized formative effect. The mixture of double images can be separated as symbolic mixture, design mixture and expressive mixture. Thirdly, the body parts has represented symbolism and sensuality in Surrealism Arts. Elsa Schiaparelli has demonstrated the expression of modern clothing as passionate, desirable, and powerful. This is the reason why her designs were absolutely different from the previous sihouette-focused clothing. Fourth, there are lots of intentional decoration that are different from actual images, such as transformation, exaggeration, minimization and repettion, as well as, re-location, re-arrangement, line-up arrangement, collage and odd materials.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.337-337
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• 2011

The elecronic absorption and surface morphology evolution of two types of molecular double layer thin films, copper phthalocyanine(CuPc) layer deposited on top of chloro[subphtalocyaninato]boron(III) (SubPc) layer, denoted as SubPc/CuPc, and vice versa, at various thicknesses were invertigated using ultraviolet(UV)-visible spectroscopy and atomic force microscopy (AFM). Both types of double layer structures showed similar broadened absorption patterns in UV-visible region which were well consistent with fitted spectra by a simple linear combination of single layer absorption spectra of two materials. In contrast, the surface morphology of double layer structures was dependent on the order of deposition. For CuPc/SubPc structures, the surface morphology was characterized by elongated grains, characteristic of SubPc thin films, indicating the morphological influence of underlying CuPc layer on subsequent SubPc layer was not large. For SubPc/CuPc structures, however, the underlying SubPc layer acted as a morphological template for the subsequently deposited CuPc layer. It was also observed that the grain size of CuPc layer varied by the thickness of underlying SubPc layer.

• Journal of Species Research
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• v.12 no.3
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• pp.203-211
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• 2023

Five ciliate species of Euplotes were isolated from fresh and coastal water during a sampling survey to identify unrecorded ciliates in South Korea. Their morphology was investigated using live observation, protargol and "wet" silver nitrate staining methods. Brief descriptions and microphotographs of each species and a comparison with related species are provided. Euplotes focardii is characterized by an average size of 65×47 ㎛ after protargol impregnation, 6 dorsal and 3 ventral ridges and dorsal argyrome pattern of double-eurystomus type. Euplotes nobilii shows an average size of 34×20 ㎛ after protargol staining, 6 dorsal and 3 ventral ridges and dorsal argyrome pattern of double-patella type. Euplotes octocarinatus, the only freshwater species described in the present study, is characterized by an average size of 66×46 ㎛ after protargol impregnation, 6 dorsal and 3 ventral ridges and dorsal argyrome pattern of double-patella type. Euplotes petzi has an average size of 43×30 ㎛ after protargol staining, a macronucleus hook-shaped and dorsal argyrome pattern in double-patella type. Euplotes raikovi is characterized by an average size of 40×24 ㎛ after protargol staining, 6 dorsal and 3 ventral ridges and dorsal argyrome pattern of double-patella type.