• 한국안전학회지
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• 제29권5호
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• pp.67-73
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• 2014

Construction equipment such as tower crane should be installed in a field without appropriate anchorage to cause a collapse of crane. The anchorage capacity can be varied with Anchor length, concrete strength, anchor diameter, hooked or non hooked these variables will be made and tested in the study. It is shown what anchorage capacity will be more effective case by case. Hooked and non-hooked rebar anchor concrete weight with dia 22mm rebar are shown with initial displacement at 170~220KN of hooked case and 200~210KN of non-hooked one which are linearly increased, without any ductility behavior with almost brittleness. Three(3) same test pieces are almost similarly behaviored without relation to hooked or non-hooked cases. It is found out that the bigger diameter of rebar becomes, the more resistant capacity could be made, but conversely ductility against sudden collapse similar to brittleness becomes the more insufficient. It is also found out that dia 16mm rebar could be more effectively applied to heavy support weight at construction sites.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.387-388
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• 2008

This paper presents the design approach and test results of the Q-band precision subminiature coaxial adaptor based on transmission line theory using multi-step impedance and air-holes to increase its cutoff frequency. In order to increase the frequency performance, the adaptor is designed with hooked structure, fixing step, multi-air-holes, and outer conductor. The return loss increments due to the hooked structure and multi air-holes are minimized to 2 dB and 1.5 dB, respectively. A VSWR(Voltage Standing Wave Ratio) of <1.2 is obtained from DC to 40 GHz, while guaranteeing the durability of the adaptor from room-temperature$(25^{\circ}C)$ to $120^{\circ}C$.

• 한국안전학회지
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• 제30권1호
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• pp.40-46
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• 2015

Many construction equipment or supporting structure should be installed in a field without appropriate anchorage to cause a collapse of those. Anchor length, anchor diameter, hooked or non hooked will be made and tested in the study. This one will be analyzed and compared with the previous study in order to find out some difference, strength by strength, based on this study. Embedded re-bar and the resistant capacity against pulled out force of re bar have been tested and analyzed by concrete design strength and rebar diameter in the study. 21Mpa and 24MPa compressive strength which are used in construction practice have been applied as variables. Those rebars are composed of D13, D16. D22 which are mostly used at construction sites. The followings are summarized as conclusions.1) ductility is not increased as rebar diameter becomes larger under the condition of non-hooked anchorage.2) those are two times of displacement difference between small diameter of rebar and large one with hooked anchorage of rebar while being 1/10 times difference with non-hooked condition but, only 10% difference of maximum load are shown, not conspicuously between hooked and non-hooked condition.3) displacement related to ductility can be three(3) times decreased if only concrete compressive strength and rebar diameter become larger with heavy support weight.

• International Journal of Concrete Structures and Materials
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• 제11권2호
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• pp.391-401
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• 2017

In this study, the effects of water-to-binder (W/B) ratio and replacement ratio of blast furnace slag (BFS) on the compressive strength of concrete were first investigated to determine an optimized mixture. Then, using the optimized high-strength concrete (HSC) mixture, hooked steel fibers with various aspect ratios and volume fractions were used as additives and the resulting mechanical properties under compression and flexure were evaluated. Test results indicated that replacement ratios of BFS from 50 to 60% were optimal in maximizing the compressive strength of steam-cured HSCs with various W/B ratios. The use of hooked steel fibers with the aspect ratio of 80 led to better mechanical performance under both compression and flexure than those with the aspect ratio of 65. By increasing the fiber aspect ratio from 65 to 80, the hooked steel fiber volume content could be reduced by 0.25% without any significant deterioration of energy absorption capacity. Lastly, complete material models of steel-fiber-reinforced HSCs were proposed for structural design from Lee's model and the RILEM TC 162-TDF recommendations.

• Korea-Australia Rheology Journal
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• 제18권2호
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• pp.99-102
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• 2006

Primitive chain network model for block copolymers is used here to simulate molecular dynamics in the entangled state with acceptable computational cost. It was found that i) the hooking procedure rearranging the topology of the entangled network is critical for the equilibrium structure of the system, and ii) simulations accounting for the different chemistry, i.e., with a biased hooking probability based on interaction parameter ${\chi}$ for selection of the hooked partner, generates a reasonable phase diagram.

• 한국어류학회지
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• 제25권1호
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• pp.33-37
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• 2013

한국산 송사리속 2종에 대한 인두골과 인두치의 구조적 차이를 조사하였다. 그 결과 송사리 O. latipes와 대륙송사리 O. sinensis의 인두골은 모두 1쌍의 물방울 모양(stilliform)의 상인두골과 사각형 모양 (rectangular form)의 하인두골로 구성되었다. 특히 송사리와 대륙송사리의 인두치 열수에 있어서 상인두골은 각각 11~12열, 11~12열을 나타냈고 하인두골이 각각 6~7열, 5~6열을 나타냈다. 또한 인두치에서 송사리는 이빨의 끝이 옆으로 휘어지는 후크모양(top-hooked type)인 반면에, 대륙송사리는 이빨의 끝이 원뿔모양(conical type)을 나타났다. 이상과 같이 한국에 분포하는 2종의 송사리는 인두치에서 형태적 차이를 보여 주었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1354-1356
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• 2000

This paper deals with a 300kV dc charging system to be used ?s a voltage source in a circuit breaker synthetic short-circuit-test facility. Cockcroft-walton circuit is used to step up the rectified voltage from a single phase transformer of which primary winding is hooked up to an ac220 wall plug. Two systems with the same ratings have been designed and manufactured. The two system have been made of different supporting structure with different insulating materials. The paper describes a couple of charging schemes, system configurations and the synthetic test circuit in which the developed system is to be used.

• Animal cells and systems
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• 제16권6호
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• pp.479-487
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• 2012

Biological attachment device is optimized in insect legs for attachment onto the variety of natural substrate. We have studied the microstructural characteristics of the tarsal appendages in the ladybug Harmonia axyridis using scanning electron microscopy to reveal the attachment system of their legs. The attachment devices are composed of claws and adhesive pads. The claws are connected with pretarsal segment, and their apical diverged hooks are developed to hold rough substrates. In contrast, the adhesive pads have an adhesive function onto smooth surface. The pads are interspersed at the ventral part of each tarsomere, and are composed of two kinds of hairy setae. The discoid tip seta (DtS) has a spoon-shaped endplate usually with a rounded concave structure, whereas the pointed tip seta (PtS) has a pointed tip, usually with a hooked endplate. While the PtS is broadly localized concentrically on the marginal area of both the proximal and distal pads, the DtS can be seen at the central areas of each adhesive pad except for the hind legs. Our findings demonstrate the presence of the direction-dependence pattern of the fibrillar system as well as a functional modification of the tenent setae to achieve proper contact with almost any kind of substrates.

• 콘크리트학회지
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• 제11권2호
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• pp.209-220
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• 1999

터널의 숏크리트 라이닝이나 포장 콘크리트 보강용으로 요접철망(wire mesh)을 대신해서 강섬유가 사용되고 있다. 본 연구에서는 강섬유 보강으로 인한 인성평가 대상 구조물을 slab panel 구조($60{\times}60{\times}10$cm)로 하고, 강섬유 혼입률은 콘크리트 용적의 0.5% ~ 2%로 다양화하였다. 이 때 사용한 강섬유는 Dramix ZC type으로 직경은 0.8mm, 길이는 60mm이다. 강섬유 효과의 상대평가를 위한 용접철망(wire mesh)보강은 상면, 하면, 상하면 보강으로 하였다. 이들 실험 결과를 각국의 인성 평가 방법으로 비교 검토한 결과 슬래브(slab) 시험체 적용을 위한 EFNARC의 방법은 25mm의 처짐까지 측정하는 것이 너무 큰 것으로 평가되었고, 보의 휨인성 평가법을 적용하여 검토한 결과에서는 Johnston(II)방법에 의한 $I_{5.5}$ 가장 적절하였으며, JCI-SF4방법에서 지간의 1/150까지 측정하는 것은 너무 작았다. 또한 강섬유로 용접철망(wire mesh)을 효과적으로 대치할 수 있음을 알 수 있었고, 인성효과에 유용한 강섬유 혼입량은 0.5% ~ 1%범위에 있는 것으로 나타났다.

• 한국산학기술학회논문지
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• 제19권10호
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• pp.648-654
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• 2018

본 노면에 설치되어있는 맨홀의 지속적인 관리를 위해서는 맨홀의 개폐가 쉬워야 한다. 가혹한 조건하에 있는 맨홀은 틀과 커버가 고착되어 개폐가 어렵기 때문에 맨홀을 열 때 부양이 가능한 맨홀이 요구된다. 본 연구에서는 잠금식 맨홀을 부양식 맨홀로 개선하기 위한 부양 기구의 설계를 진행하였다. 잠금식 맨홀의 기구는 중앙에 위치한 볼트를 돌리면 볼트와 연결된 허브가 하강하고, 허브와 연결되어 있는 후크를 회전시키게 된다. 후크의 끝단이 맨홀 틀에 걸리도록 되어있다. 본 연구에서는 맨홀의 부양이 가능하도록 후크에 보조장치를 설치하도록 하였다. 부양 기능을 수행할 후크의 항복응력의 70%를 기준으로 약 300kg의 부양력을 지지할 수 있도록 구조를 설계하였다. 유한요소법을 이용한 구조해석을 통하여 형상 설계를 수행하였다. 우선 단순화된 2차원 모델로 1차 기초설계를 수행하고, 3차원 모델을 통하여 부착위치와 형상을 설계하였다. 설계된 형상에 대하여 구조적 문제점을 찾아보기 위하여 3D 프린팅을 통하여 축소 모델을 출력하였고, 기능이 작동함을 확인하였다. 최종적으로 가공을 통하여 부양 기구를 제작하여 기존의 잠금식 맨홀에 적용한 결과 평균 6.1 mm 정도의 부양이 가능함을 확인하였다.