• 한국정밀공학회지
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• 제21권8호
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• pp.129-135
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• 2004

This paper discussed on the effect of an intermediate support on the stability of elastic material subjected to dry friction force. It is assumed in this paper that the dry frictional force between a tool stand and an elastic material can be modeled as a distributed follower force. The elastic material on the friction material is modeled for simplicity into an elastic beam on Winkler-type elastic foundation. The stability of beams on the elastic foundation subjected to distributed follower force is formulated by using finite element method to have a standard eigenvalue problem. The first two eigen-frequencies are obtained to investigate the dynamics of the beam. The eigen-frequencies yield the stability bound and the corresponding unstable mode. The considered beams lose its stability by flutter or divergence, depending on the location of intermediate support.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.421-425
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• 2007

In the fabrication of dry adhesive structure, increasing contact-points or contact-area is the primary goal because the adhesive force grows in proportion to the contact-area. The simplest way to extend the contact surface is the fabrication by using soft materials. However, the column-array structure could confront the matting phenomenon which columns are stuck together. Therefore, we need a novel design to reduce the effective stiffness with adequate stiff materials like a gecko's setae. In this study, we propose a novel design for the dry adhesive structure. Moreover, we analyzed whether the adhesive structure conforms the rough surface sufficiently through finite element method adopted the non-bonding interaction as the body force. Also, we fabricated the novel structures via UV lithography and some techniques. In addition, we examined the adhesive force of the novel structures.

• 대한가정학회지
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• 제35권2호
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• pp.111-122
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• 1997

This thesis researched for the conservation of a suit of armor, one glove, one belt, and on knife case that General Jung, Gong-chung had been worn in the early 17 th centuries. The armor was Doojung-kab for the battle. It was made of two kinds of fabrics, one of them was silk satin's outer fabrics, the other was quilt4d cotton's lining. as the armor was made of silk and cotton, it was treated by dry solvents and dry soap. In the dry cleaning method, used solvents were n-hexane, cyclohexane, benzene, and n-decane. the volume ratio of dry soap was 120: 1. The reaction temperature was 30℃, and reaction time was 10 to 30 minutes per one turn. The glove, belt and knife case were made with leather. They were dipped on the polyethyleneglycol 150 saturated solution during 24hours at 50℃ and then dried naturally. They were washed by toluene to remove the untreated pp.E.G. on the surfaces. It was sterilized by two gases of methylenebromide and ethyleneoxied. For the conservation, it was packed thoroughly by ？ polyethylene film sheet without air.

• Journal of Mechanical Science and Technology
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• 제19권4호
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• pp.927-935
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• 2005

In the present paper the dynamics of the structure varying multibody systems caused by stick-slip motion with two-dimensional dry friction are analyzed. The methods to determine friction force both in stick and slip states are described. The direct method of considering the wagon bogie system as a structure varying system was used to consider two dimensional friction at the wheelset-side frame connection. The concept of friction direction angle used to determine the friction force components of two-dimensional dry friction both in the stick and slip motion states was used. A speed depended friction coefficient was used and described approximately by hyperbolic secant function. All switch conditions were derived and friction forces both for stick and slip states. Some simulation results are provided.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.249-251
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• 2001

A novel technology for recycling valuable metals contained in waste dry-battery by vacuum metallurgy was devised by theoretical analysis. On the condition of the total chamber pressure of 1.013$\upsilon$10$^1$Pa, Hg, Cd and Zn are distilled in the temperature range of 773~973K, Pb is volatilized in the range of 1173~1273K while Mn, Cu, Fe and C are remained in residual. MnO$_2$and ZnO are reduced by carbon in waste dry-battery in 773~1273K. Pure metals including Zn, Cd, Hg and Pb can be recovered respectively from their mixed vapor by fractional condensation. Metal Cu and MnO$_2$can be obtained from the residual by hydrometallguical method. The technology can eliminate the pollution of Cd, Hg and Pb to environment.

• 전기학회논문지
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• 제60권2호
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• pp.301-308
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• 2011

This paper deals with the coupled electromagnetic-mechanical field analysis for short-circuit electromagnetic force of the dry-type transformer. The short-circuit currents are calculated using external circuit in accordance with short-circuit test equipment. According to short-circuit current, the generated magnetic leakage flux density in dry-type transformer model is calculated by finite element method. The radially-directed electromagnetic forces in windings are calculated using electromagnetic field analysis and then axially-directed electromagnetic forces in windings are calculated using electromagnetic-mechanical field analysis. The calculated axially-directed electromagnetic forces in high voltage winding are compared to those of measured ones and showed good agreement with experimental results.

• 한국정밀공학회지
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• 제21권11호
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• pp.179-185
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• 2004

The effect of viscous damping on stability of beam resting on an elastic foundation subjected to a dry friction force is analytically studied. The beam resting on an elastic foundation subjected to dry friction force is modeled for simplicity into a beam resting on Kelvin-Voigt type foundation subjected to distributed follower load. In particular, the effects of four boundary conditions (clamped-free, clamped-pinned, pinned-pinned, clamped-clamped) on the system stability are considered. The critical value and instability type of columns on the elastic foundation subjected to a distributed follower load is investigated by means of finite element method for four boundary conditions. The elastic foundation modulus, viscous damping coefficient and boundary conditions affect greatly both the instability type and critical load. Also, the increase of damping coefficient raises the critical flutter load (stabilizing effect) but reduces the critical divergence load (destabilizing effect).

• 대한기계학회논문집A
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• 제28권2호
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• pp.143-148
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• 2004

This paper discussed on the stability of elastic material subjected to dry friction force for low boundary conditions: clamped free, clamped-simply supported, simply supported-simply supported, clamped-clamped. It is assumed in this paper that the dry frictional force between a tool stand and an elastic material can be modeled as a distributed follower force. The friction material is modeled for simplicity into a Winkler-type elastic foundation. The stability of beams on the elastic foundation subjected to distribute follower force is formulated by using finite element method to have a standard eigenvalue problem. It is found that the clamped-free beam loses its stability in the flutter type instability, the simply supported-simply supported beam loses its stability in the divergence type instability and the other two boundary conditions the beams lose their stability in the divergence-flutter type instability.

• 한국초지조사료학회지
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• 제18권2호
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• pp.113-122
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• 1998

This experiment was conducted to establish the cultural method of triticale(Triticum Secalotriticum Saratoviense Meister) as a whole crop silage by evaluating the effect of seeding date and nitrogen fertilization rate on forage yields and feeding value. Heading date, flowering date, and the dough stage of development came significantly earlier as triticale was seeded earlier. Soilage, dry matter yields and percent dry matter significantly varied with seeding dates and crude ash, NFE and TDN. However, TDN yield was significantly reduced by delayed seeding. Macromineral contents were not affected by seeding date. Soilage, dry matter yield, and percent dry matter significantly increased as nitrogen fertilization rate increased. The contents of crude protein, crude fat, crude ash, NFE, TDN and TDN yield also significantly increased. In contrast, crude fiber content of triticale decreased with increasing N fertilization rate.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.215-216
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• 2019

The following conclusions were reached through the research on the development of the required performance extraction tools for the application and utilization of various construction methods of lightweght dry wall. 1) Performance required for walls of apartment buildings can be divided into safety, habitation, durability and productivity. Among these, horizontal load resistance, shock resistance, anti-seismic performance, insulation, and acoustic characteristics are the main performance that correspond to dry walls. In addition, safety related to toxic gases and contaminants are required according to recent eco-friendly requirements. 2) To select a wall according to the required performance of an inner wall applied to an apartment, a map tool in the form of 2D matrices was constructed to enable the required performance to be applied, indicating that the wall location and wall material and its differentiating according to the old method.