• 한국재난정보학회 논문집
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• 제12권4호
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• pp.432-439
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• 2016

방호 방폭 보강용 복합재료의 특성상 모델을 구성하고 사용하기 위해서는 재료 각각의 물성치가 필요하며, 이러한 물성 데이터를 도출하기 위해서는 수많은 실험을 통해 도출된 결과를 여러 계산식을 통하여 도출된 값으로 입력해야 하며, 일반적인 재료가 아닌 특수 목적용 소재의 경우는 이를 수행하는데 많은 어려움이 있다. 본 연구에서는 Ansys Workbench 환경에서 제공하는 복합재 적용 물성을 적용하여 ACP와 AUTODYN에서 방호 방폭 보강용 복합섬유 패널의 모델링 및 구조 해석을 수행하였다.

• 대한기계학회논문집A
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• 제31권8호
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• pp.870-879
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• 2007

In this study, various damage modes in bending unimorph piezoelectric composite actuators with a thin sandwiched PZT plate during bending fracture tests have been evaluated by monitoring acoustic emission (AE) signals in terms of waveform and peak frequency as well as AE parameters. Three kinds of actuator specimens consisting of woven fabric fiber skin layers and a PZT ceramic core layer are loaded with a roller and an AE activity from the specimen is monitored during the entire loading using an AE transducer mounted on the specimen. AE characteristics from a monolithic PZT ceramic with a thickness of $250{\mu}m$ are examined first in order to distinguish different AE signals from various possible damage modes in piezoelectric composite actuators. Post-failure observations and stress analyses in the respective layers of the specimens are conducted to identify particular features in the acoustic emission signal that correspond to specific types of damage modes. As a result, the signal classification based on waveform and peak frequency analyses successfully describes the failure process of the bending piezoelectric composite actuator exhibiting diverse failure mechanisms. Furthermore, it is elucidated that when the PZT ceramic embedded actuators are loaded mechanical bending loads, the failure process of actuator specimens with different lay-up configurations is almost same irrespective of their lay-up configurations.

• Ocean and Polar Research
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• 제28권3호
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• pp.287-290
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• 2006

Eye growth and lens diameter of brown croaker Miichthys miiuy were positively allometric between hatching and 180 days post-hatch (d.p.h.). Eye growth in relation to head length and head height was nearly isometric. Eyes were formed completely at 14 d.p.h. At this age, the eye has a crystalline lens, an optic nerve fiber layer, a ganglion cell layer, an inner plexiform layer, an inner nuclear layer, an outer plexiform layer, an outer nuclear layer, an outer limiting membrane, and a pigment epithelium. The essential demands that must be met by the retina in this species pertain to light sensitivity and spatial resolution.

• 패션비즈니스
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• 제3권4호
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• pp.113-129
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• 1999

The purpose of this study is to discover the changes and characteristis of modern knitwears from the 1920's to the 1990's. The result of this study is as follows: The popular knitwears in the 1920's had a simple boxy-line and modern unisex image with a sporty look. The knitwears in the 1930's-1950's had seen more short, feminine detail and texture, fit silhouette with syntheyic fibers. In the 1960's, the knitwears of sporty look and unisex style was popularized by young peaples, and crochet with handkniting by the fiber artists was popularized. In the 1970's-80's, the layered looks and unisex styles of knitwears were popularized by influence of a ecology mood and a woman movemant. And various patterns was developed with the computer machine. The items of outer knitwear was increased by the use of fancy yarns and the knitwears as the total fashion was popularized. In the 1990s, the knitwears had a very forceful characteristics by the mixed style and the technique of design developed into the post-modernism. The key words of the character of the modern knitwears are funtional pursuit, unisex, high value, hightechnique, art. By the change of the life style and the develope of technical innovation, the knitwears will be the key item to leading the fashion in the 21th.

• 한국식품영양과학회지
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• 제21권6호
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• pp.627-632
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• 1992

식이 중의 펙틴이 식이의 상부소화관내 이동 속도에 미치는 영향을 조사하였다. 흰쥐에게 무섬유식이 또는 10% 펙틴식이를 공급하면서 식이의 이동속도 표시물질인 51-Cr를 투여하였다. 51-Cr 투여후 20분부터 6시간까지 정해진 시간 간격을 두고 동물을 희생시켜, 51-Cr이 소화관에서 이동하는 속도를 측정하였다. 51-Cr를 섭취한 뒤 3시간까지 펙틴은 51-Cr이 위에서 소장으로 이동해 나가는 속도를 유의성있게 증가시켰다. 51-Cr을 섭취한 후 3시간과 4시간 사이에 펙틴은 51-Cr이 소장을 통과하여 맹장으로 이동해 나가는 속도를 증가시켰다. 따라서 펙틴이 포도당 부하후 또는 식이섭취후 혈당치와 인슐린치의 급격한 증가를 완화시키는 효과가 펙틴이 상부소화관내 이동속도를 지연시키기 때문이라는 가설은 정확하지 않은 것으로 보인다.

• International Journal of Concrete Structures and Materials
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• 제11권2호
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• pp.247-259
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• 2017

This paper presents a fatigue assessment model that was developed for corroded reinforced concrete (RC) beams strengthened using prestressed carbon fiber-reinforced polymer (CFRP) sheets. The proposed model considers the fatigue properties of the constituent materials as well as the section equilibrium. The model provides a rational approach that can be used to explicitly assess the failure mode, fatigue life, fatigue strength, stiffness, and post-fatigue ultimate capacity of corroded beams strengthened with prestressed CFRP. A parametric analysis demonstrated that the controlling factor for the fatigue behavior of the beams is the fatigue behavior of the corroded steel bars. Strengthening with one layer of non-prestressed CFRP sheets restored the fatigue behavior of beams with rebar at a low corrosion degree to the level of the uncorroded beams, while strengthening with 20- and 30%-prestressed CFRP sheets restored the fatigue behavior of the beams with medium and high corrosion degrees, respectively, to the values of the uncorroded beams. Under cyclic fatigue loading, the factors for the strengthening design of corroded RC beams fall in the order of stiffness, fatigue life, fatigue strength, and ultimate capacity.

• Structural Engineering and Mechanics
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• 제28권6호
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• pp.727-747
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• 2008

In the framework of the SPEAR (Seismic PErformance Assessment and Rehabilitation) research Project, an under-designed three storey RC frame structure, designed to sustain only gravity loads, was subjected, in three different configurations 'as-built', Fiber Reinforced Polymer (FRP) retrofitted and rehabilitated by reinforced concrete (RC) jacketing, to a series of bi-directional pseudodynamic (PsD) tests under different values of peak ground acceleration (PGA) (from a minimum of 0.20g to a maximum of 0.30g). The seismic deficiencies exhibited by the 'as-built' structure after the test at PGA level of 0.20g were confirmed by a post - test assessment of the structural seismic capacity performed by a nonlinear static pushover analysis implemented on the structure lumped plasticity model. To improve the seismic performance of the 'as-built' structure', two rehabilitation interventions by using either FRP laminates or RC jacketing were designed. Assumptions for the analytical modeling, design criteria and calculation procedures along with local and global intervention measures and their installation details are herein presented and discussed. Nonlinear static pushover analyses for the assessment of the theoretical seismic capacity of the structure in each retrofitted configuration were performed and compared with the experimental outcomes.

• Advances in concrete construction
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• 제5권5호
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• pp.539-561
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• 2017

In this study, the effects of initial damage of concrete columns on the post-repair performance of reinforced concrete (RC) columns strengthened with carbon-fiber-reinforced polymer (CFRP) composite are investigated experimentally. Four kinds of compression-damaged RC cylinders were reinforced using external CFRP composite wraps, and the stress-strain behavior of the composite/concrete system was investigated. These concrete cylinders were compressed to four pre-damaged states including low -level, medium -level, high -level and total damage states. The percentages of the stress levels of pre-damage were, respectively, 40, 60, 80, and 100% of that of the control RC cylinder. These damaged concrete cylinders simulate bridge piers or building columns subjected to different magnitudes of stress, or at various stages in long-term behavior. Experimental data, as well as a stress-strain model proposed for the behavior of damaged and undamaged concrete strengthened by external CFRP composite sheets are presented. The experimental data shows that external confinement of concrete by CFRP composite wrap significantly improves both compressive strength and ductility of concrete, though the improvement is inversely proportional to the initial degree of damage to the concrete. The failure modes of the composite/damaged concrete systems were examined to evaluate the benefit of this reinforcing methodology. Results predicted by the model showed very good agreement with those of the current experimental program.

• Computers and Concrete
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• 제21권6호
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• pp.607-622
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• 2018

A non-linear finite element model (FEM) was constructed using a three-dimensional software (ATENA-3D) to investigate the effect of strengthening on the behavior of prestressed hollow-core (PHC) slabs with or without openings. The slabs were strengthened using near surface mounted (NSM)-carbon fiber reinforced polymer (CFRP) strips. The constructed model was validated against experimental results that were previously reported by the authors. The validated FEM was then used to conduct an extensive parametric study to examine the influence of prestressing reinforcement ratio, compressive strength of concrete and strengthening reinforcement ratio on the behavior of such slabs. The FEM results showed good agreement with the experimental results where it captured the cracking, yielding, and ultimate loads as well as the mid-span deflection with a reasonable accuracy. Also, an overall enhancement in the structural performance of these slabs was achieved with an increase in prestressing reinforcement ratio, compressive strength of concrete, external reinforcement ratio. The presence of openings with different dimensions along the flexural or shear spans reduced significantly the capacity of the PHC slabs. However, strengthening these slabs with 2 and 4 (64 and $128mm^2$ that represent reinforcement ratios of 0.046 and 0.092%) CFRP strips was successful in restoring the original strength of the slab and enhancing post-cracking stiffness and load carrying capacity.

• 한국축산식품학회지
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• 제41권6호
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• pp.983-996
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• 2021

This study explored the physicochemical, textural, and sensorial properties of a meat analog (MA) as compared to beef and pork meats. Results illustrate that MA patties had lower moisture, fat, and protein content, as well as higher ash and crude fiber than beef and pork. Likewise, MA patties had a higher pH, lightness (L^*), and redness (a^*) than either beef or pork. Pork meat exhibited the highest released water (RW) and cooking loss (CL) values, followed closely by MA with beef displaying the lowest values. Regardless of patty type, the post-cooking diameter patties were reduced significantly (p<0.05). However, the Warner-Bratzler shear force (WBSF), hardness, chewiness, and gumminess of beef were significantly higher than that of either pork or MA. The visible appearance of MA patties had more porous and loose structures before and after cooking. Consequently, based on sensory parameters, MA patties demonstrated the higher values for appearance and firmness, followed by beef and pork respectively, although the difference was not statistically significant. Therefore, the current study demonstrated that some physicochemical, textural, and sensory characteristics of beef and pork exhibited the most similarity to MA.