• Advances in nano research
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• 제12권4호
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• pp.365-374
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• 2022

Intermediate filaments are the mechanical ropes for both cytoskeleton and nucleoskeleton of the cell which provide tensile force to these skeletons. In providing the mechanical support to the cell, they are likely to buckle. We used conventional Euler buckling model to find the critical buckling force under different boundary conditions which they assume during different functions. However, there are many experimental and theoretical studies about other cytoskeleton components which demonstrate that due to mechanical coupling with the surrounding surface, the critical buckling force increases considerably. Motivated with these results, we also investigated the influence of surface effects on the critical buckling force of intermediate filaments. The surface effects become profound because of increasing ratio of surface area of intermediate filaments to bulk at nano-scale. The model has been solved analytically to obtain relations for the critical forces for the buckling of intermediate filaments without and with surface effects. We found that critical buckling force with surface effects increases to a large extent due to mechanical coupling of intermediate filaments with the surrounding surface. Our study may be useful to develop a unified experimental protocol to characterize the physical properties of Intermediate filaments and may be helpful in understanding many biological phenomenon involving intermediate filaments.

• Structural Engineering and Mechanics
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• 제87권6호
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• pp.541-554
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• 2023

An unbraced cantilever beam subjected to loads which cause bending about the major axis may buckle in a flexuraltorsional mode by deflecting laterally and twisting. For the efficient design of these structures, design engineers require a simple accurate equation for the elastic flexural-torsional buckling load. Existing solutions for the flexural-torsional buckling of cantilever beams have mainly been derived by numerical methods which are tedious to implement. In this research, an attempt is made to derive a theoretical equation by the energy method using different buckled shapes. However, the results of a finite element flexural-torsional buckling analysis reveal that the buckled shapes for the lateral deflection and twist rotation are different for cantilever beams. In particular, the buckled shape for the twist rotation also varies with the section size. In light of these findings, the finite element flexural-torsional buckling analysis was then used to derive simple accurate equations for the elastic buckling load and moment for cantilever beams subjected to end point load, uniformly distributed load and end moment. The results are compared with previous research and it was found that the equations derived in this study are accurate and simple to use.

• Earthquakes and Structures
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• 제25권2호
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• pp.113-123
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• 2023

A novel type of buckling restrained brace with built-up angle steel was developed. The core segment was formed by welding angle steel, and the middle section was reduced by cutting technology to solve the problem that the end of BRB was easy to buckle. The experimental program has been undertaken to study the performance of BRBs with different unbonded materials (silica gel, kraft paper) and different filler materials (ordinary concrete, full light-weight concrete). Four specimens were designed and fabricated for low cycle reciprocating load tests to simulate horizontal seismic action. The failure mode, hysteretic curves, tension-compression unbalance coefficient and other mechanical parameters were compared and analyzed. The finite element software ABAQUS was used to conduct numerical simulation, and the simulation results were compared with the experimental phenomena. The test results indicated that the hysteretic curve of each specimen was plump. Sustaining cumulative strains of each specimen was greater than the minimum value of 200 required by the code, which indicated the ductility of BRB was relatively good. The energy dissipation coefficient of the specimen with silica gel as unbonded material was about 13% higher than that with kraft paper. The experimental results were in good agreement with the simulation results.

• 대한영상의학회지
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• 제81권4호
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• pp.806-831
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• 2020

근골격계의 외상은 소아가 응급실로 내원하는 가장 흔한 원인 중에 하나이다. 소아에서 뼈는 아직 완전히 골화가 되지 않았기 때문에 불완전 골절(소성변형, 생나무 골절, 죔쇠 골절)과 같이 성인과는 다른 영상의학적 특성을 보이기도 하며, 성장판의 손상으로 인해 성장 장애를 유발하기도 한다. 소아는 연령에 따라서 활동 범위나 활동 양상이 다르기 때문에 분만 손상에서부터 낙상, 교통사고에 이르기까지 다양한 기전에 의해서 골절이 발생하며, 각각의 손상기전에 따라 특징적인 골절의 발생 부위 및 골절의 형태를 보이기도 한다. 본 종설에서는 소아의 다양한 근골격계 외상 중 소아에서 흔하게 볼 수 있는 사지 골절의 영상의학적 특성에 대해서 고찰해보고자 한다.

• Structural Monitoring and Maintenance
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• 제5권3호
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• pp.391-416
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• 2018

The purpose of this article is to strengthen concrete structures using buckling and non-buckling braces. Connection plates are modeled in three shapes including the effect of 1.5t hinge zone length, 2t one and without the zone (1.5t-CP, 2t-CP and WCP). According to the verification performed with ABAQUS software, the connection plates which are superior in ductility and strengthening are found. The results show adding steel braces in concrete moment frames increase the strength and stiffness of the structures up to about 12 and 3 times, respectively. The frame strength increased about 21 and 25 percent with considering the effect of 2t hinge length in connection plates compared to 1.5t-CPs and WCPs. Also the ductility of retrofitted frames with 2t-CP improved 2.06 times more than WCP ones. Thus, 2t-CP sample is the best choice for connecting steel braces to concrete moment frames for retrofitting them. Afterwards, optimum conditions for elemental coating in braces with no buckling are assessed. The length of concrete coatings could be reduced about 30 percent, and buckling did not occur. Therefore, the weight of restraining coating decreased, and its performance improved. It is worth noting that BRBs could be constructed with only steel materials, which have outer steel tubes too. In fact, only the square cross sections of the tube profiles are appropriate for removing the filler concrete, and the rectangular ones are prone to buckle around their weak axis.

• 패션비즈니스
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• 제11권4호
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• pp.204-220
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• 2007

The background of Korean Ethnical Costume was originated from those northern mounted nomadic groups, which was Scythe style Costume Culture. Through the antique records and paintings of tombs bequests hereby describe the forms of Scythian Cotume (1) Headgear : There was Conical Cap(or Pointed Cap), Feathered Cap, and Crown. (2) Clothes : Both Men and Women wore Jacket as upper garment with leftsided collars, narrow sleeves to the length of the hip line. As lower garment, they wore the tight Trousers and Kungo(:窮袴)that was attached with gusset. (3) Belts and Boots : On the upper garment bound the leather Belts that was hanged a hook that was shaped of animal form at the end. Scythian Buckles was divided into six groups, animal-shaped, animal's head shaped, animal fight-shaped, rectangle-shaped, rectangle openwork-shaped, genre scene shaped Buckle. To the Boots, they wore leather boots. (4) Ornaments : Ornaments divided into Dress Trimming(:Gold plaques), Earrings, Necklaces(;Torques), Bracelets, Rings. Scythian Gold Plaques were divided into several types according to the shape, animal style(curved beast shape, profile shape, head reversed over its back shape), round shape, quadrilateral form, star shape, flower shape, crescent shape, bundle shape, human appearance. Earrings consisted of a plain ring and pendant ring was a middle ornament hung from it to a pendants which hung was made of heart shaped leaves of the tree, beads-linked. Scythian Torques were divided into several types according to the shape, Torque with Terminal style, Spiral style, Layers style, Crescent-shaped pectoral style, Crown style. Scythian Bracelet were divided into 4 styles according to the shape, Bracelets with ends shaped like beasts style, Spiral style, Layers style, Crown with openwork style. Rings were rhomb-shaped and animal shaped styleRings (5) Animal motifs used in Scythian ornaments appears that in some cases the work was intended to be purely ornamental, while many times the motifs had symbolic meaning (such as the successful dominance of the aggressor over the victim portrayed in the attack scenes). Magical use of symbols may have been inten-ded to guarantee the power of the aggressor.

• 복식
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• 제63권3호
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• pp.1-16
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• 2013

Xiognu people were the first of the Central-Asian nomads to establish a nation in 209 B.C. They always moved around looking for places to breed their animals and fertile grounds, so they wore clothes made of fur and leather and covered their tents with felt from the livestock. This research studies on the literatures, costumes and the achievement of archaeological excavation. Furthermore, to investigate on costumes excavated of Xiongnu, we visited the Mongolian National Museum and the Hermitage Museum. A corn-hat made of felt, a felt hat with ear flaps and a golden crown with a bird on the top were unearthed from a tomb of Xiongnu in Inner mongolia. Women usually wore pigtails, and men wore pigtails or ponytails but they cut their hair short when holding a funeral. Many pigtails discovered in Noyon uul tombs can be considered as their funeral customs. The Xiongnu wore a round or v-neck caftan attached straight sleeves reaching knees in the left folded style, and because they always rode horses, having the length of the caftan not go past their buttocks would have made it more convenient for them. During the period of Western Han, Ho refered to Xiongnu and it became a common name for northern races. They used leather belts and an animal-designed buckle was found. Women commonly rouged their cheeks for a vivid and cute look, and many ornaments were excavated including bracelets, rings and decorations made of gold, silver, copper and jade, among which there were hair ornaments used to identify one's class. A horse pattern with wings and a horn of Golmod T20 was substitution for the Schythian use of deer. Patterns or shape of unearthed articles present in the Xiongnu culture in Noyon uul had a close relationship with Altaic, Greek and Persian cultures. The Xiongnu clothing was made of animals' skin and fur, woolen textiles and felt. It was folded to the left for upper garments, and the pants were adjusted using a belt and shoes were made of leather, which was very suitable for protection against the cold and horse riding. Mobility played a significant role in their clothing.

• 복합신소재구조학회 논문집
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• 제5권2호
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• pp.1-8
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• 2014

Fiber reinforced polymeric plastic (FRP) materials have many advantages over conventional structural materials, i.e., high specific strength and stiffness, high corrosion resistance, right weight, etc. Among the various manufacturing methods, pultrusion process is one of the best choices for the mass production of structural plastic members. Since the major reinforcing fibers are placed along the axial direction of the member, this material is usually considered as an orthotropic material. However, pultruded FRP (PFRP) structural members have low modulus of elasticity and are composed of orthotropic thin plate components the members are prone to buckle. Therefore, stability is an important issue in the design of the pultruded FRP structural members. Many researchers have conducted related studies to publish the design method of FRP structures and recently, referred to the previous researches, pre-standard for LRFD of pultruded FRP structures is presented. In this paper, the accuracy and suitability of design equation for the local buckling strength of pultruded FRP I-shape compression members presented by ASCE are estimated. In the estimation, we compared the results obtained by design equation, closed-form solution, and experiments conducted by previous researches.

• 한국재료학회지
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• 제20권9호
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• pp.457-462
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• 2010

Adsorption of a water molecule on a Si (001) surface and its dissociation were studied using density functional theory to study the distribution of -OH fragments on the Si surface. The Si (001) surface was composed of Si dimers, which buckle in a zigzag pattern below the order-disorder transition temperature to reduce the surface energy. When a water molecule approached the Si surface, the O atom of the water molecule favored the down-buckled Si atom, and the H atom of the water molecule favored the up-buckled Si atom. This is explained by the attractions between the negatively charged O of the water and the positively charged down-buckled Si atom and between the positively charged H of the water and the negatively charged up-buckled Si atom. Following the adsorption of the first water molecule on the surface, a second water molecule adsorbed on either the inter-dimer or intra-dimer site of the Si dimer. The dipole-dipole interaction of the two adsorbed water molecules led to the formation of the water dimer, and the dissociation of the water molecules occurred easily below the order-disorder transition temperature. Therefore, the 1/2 monolayer of -OH on the water-terminated Si (001) surface shows a regular distribution. The results shed light on the atomic layer deposition process of alternate gate dielectric materials, such as $HfO_2$.

• 한국공간구조학회논문집
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• 제11권2호
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• pp.71-79
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• 2011

케이블 구조시스템의 경우 자기 평형 상태를 유지하기 때문에 장력이 손실된 특정 케이블을 재긴장을 하지 않으면 구조엔지니어가 요구한 하중보다 더 큰 하중이 다른 케이블에 전달되어 손상을 야기 할 수 있다. 또한, 턴버클을 이용한 재긴장 방법이 기존에 널리 적용되고 있지만 정확한 장력조절과 대구경 케이블에는 적절하지 못하고 인장재의 하중의 크기를 측정하는 것이 어렵다. 따라서 효과적으로 재긴장 할 수 있는 유압식 볼팅 접합부를 개발하고 인장력을 실시간으로 확인할 수 있는 모니터링 시스템을 적용하였다. 본 논문에서는 개발된 시스템의 현장 적용성 실험과 결과를 제시하였다.