• Journal of Biosystems Engineering
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• 제16권1호
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• pp.37-48
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• 1991

Rice plants are subjected to various forces such as natural force of wind and mechanical force of cultivating machines. Rheological behavior of the rice stem can be expressed in terms of three variables : stress, relaxation and time. The objectives of this study are to examine stress relaxation, creep and recovery characteristics on the rice stem in case of axial and radial loading. Stress relaxation with time was studied on three levels of loading rate and on four levels of applied stress. The results were summarized as follows : 1. The hysterisis losses of the rice stem distinctly observed at the radial compression in comparison with axial compression. The hysterisis loss implied that the stem to absorbed energy without being deformed beyond the yield point. 2. Ageneralized Maxwell model consisting of three elements gave a good description of the relaxation behavior of the rice stem. Rate of loading was more significant on the observed relaxation behavior within the short relaxation time, but there were little influences of rate of loading on the relaxation time. 3. The stress relaxation intensity and the residual stress increased in magnitude as the applied stress increased, but the relaxation time was little affected by the applied stress. 4. The coefficients of the stress relaxation model showed much differences in the radial compression and the axial compression, especially the higher relaxation stress of the third element was observed in the radial compression. 5. The behaviors of rice stem in creep and recovery test also might be represented by a four element Burger's model. But the coefficients of the creep model were different from those of the recovery model. 6. The steady-state phenomena of creep appeared at the stress larger than 20 MPa in Samkang and 1.8 MPa in Whajin. 7. The elastic modulus of the stem showed the range from 40 to 60 MPa. It could be considered, as a result, the rice stems had viscoelastic properties.

• 한국연초학회지
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• 제7권2호
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• pp.189-197
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• 1985

The purpose of this study is to improve the method and the apparatus for recovering freon-11 used in a process for increasing the filling capacity of tobacco. The first, the theoretical recovery rate of freon-11 was calculated from vapour pressure and thermodynamic properties of freon-11. The second, the usability of theoretical data was evaluated by the comparison between the theoretical data and the experimental data from the pilot plant. The result obtained under the present experiment condition was quite similar to the rate at 15kg/cm2 and 5$^{\circ}C$, but the theoretical data evaluated were 0.1 to 0.3% lower than the experimental data at 20 to 25kg/cm2 and 5$^{\circ}C$. The recovery rate of the cooling and the compression system was about 95% with freon-11 used in this system and that with freon-11 concentrate of waste gas was about 3 to 3.6% at 20 to 25kg/cm2 and 5$^{\circ}C$.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.323-323
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• 2000

In the tandem cold wiling mill, the quality is very in portant, and requirements for thickness accuracy become more strict. However, the mathematical model for prediction of rolling force was not considered an elastic deformation at the entry and delivery side of the contacted area between the worked roll and rolling strip so that there was so difficult to control of the thickness. To overcome this problem, the mathematical model included an elastic deformation of strip has been developed and applied to the field in order to predict the rolling force. The simulated results showed that the end of elastic recovery should be included the model, even if the effect of elastic compression was not important.

• 한국의류산업학회지
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• 제19권6호
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• pp.759-767
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• 2017

This study investigates the improvement of domestic compression stockings by comparing and analyzing the characteristics of materials and fabrics of medical compression stockings developed in Korea and domestic imported compression stockings. Among imported compression stockings currently available in Korea, three brands with high sales rates are selected by countries (USA, Italy, and Germany) to measure the physical and mechanical properties of the material. Medical compression stockings to be analyzed were selected as M size pantyhose included in 20-30mmHg. As a result, the tensile elongation of medical compression stockings selected in this study was the highest in Korean products in the ankle, while the highest in the US was in the thigh, and the elasticity of Italian products was low. The recovery rate of the kidneys was similar for all four ankles. The ankle weight was the highest except for Korean products that showed the highest weight of the thigh and difference from products of other countries. US product also showed high shape stability due to high recovery of tensile strength from high value RT. Italian products showed low banding and shear values; however, shape stability was poor with good drapeability. In Germany, LT and RT values were low, but clothing comfort was considered excellent. In Korea, LT and RT values, banding and shear characteristics were high, and drapeability was poor. Stiffness was good, but recoverability was excellent.

• 한국컴퓨터정보학회논문지
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• 제10권5호
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• pp.187-198
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• 2005

본 논문에서 차세대 IP 네트워크인 Ipv6에서의 효율적인 데이타 전송을 위한 헤더압축 기법을 제안하고자 한다. 기존의 네트워크와 최근 각광받는 무선링크의 대역폭은 제한적인 물리적, 지역적 한계로 인해 점차 줄어들고 있으며 이것은 사용자의 처리율(Throughput)을 감소시키는 큰 요인으로 들 수 있다. 본 논문에서는 기존의 헤더압축방식인 RFC2507기법과 확장된 형태의 헤더압축 기술과 에러 감지시 신속하고 적절한 복구기술에 관하여 중점을 두고 있는 ROHC(RFC3095) 기법에 관하여 기술하였고, 특히 이 기법의 개선에 역점을 두었다. RTP헤더에 포함된 SN, TS의 압축효율과 견고성(Robust)을 향상시키는 확장된 ROHC(Extended ROHC) 알고리즘을 연구하였고, 그 알고리즘을 위한 확장 헤더의 표준을 제시하였으며, 개선된 알고리즘을 시뮬레이션을 통하여 증명하기 위해 비디오 패킷을 대상으로 실험하였다.

• 대한수학회지
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• 제33권4호
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• pp.955-982
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• 1996

In surface compression applications, one of the main issues is how to efficiently store and calculate the computer representation of certain surfaces. This leads us to consider a nonlinear approximation by box splines with free knots since, for instance, the nonlinear method based on wavelet decomposition gives efficient compression and recovery algorithms for such surfaces (cf. [12]).

• Elastomers and Composites
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• 제40권4호
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• pp.258-265
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• 2005

스포츠화 중창용으로 사용되는 PU, IP 및 PH 등 세가지 종류의 발포체를 일정한 응력으로 반복압축한 후, 반복압축에 따른 발포체의 압축력, 영구변형, 회복력 등에 미치는 영향을 고찰하였다. 발포체의 반복압축에 따른 최대압축력은 PU의 경우는 거의 변화하지 않는 것으로 나타났으나 IP의 경우 최대 압축력은 크게 저하되었다. PU는 반복압축에 따른 발포체의 영구변형은 미소하였으나 PH의 경우 반복압축횟수가 증가함에 따라 현저하게 증가하는 경향을 나타내었다. 경도 45인 발포체를 5만회 반복압축 한 경우 발포체의 영구변형은 PU

• Journal of Biosystems Engineering
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• 제14권3호
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• pp.181-187
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• 1989

The mechanical and rheological properties of agricultural materials which influence the machine design or handling are not completely understood. Agricultural materials do not react in a purely elastic manner, and their responses when subjected to stress and strain appear a combination of elastic and viscous behavior. Many researchers have studied the mechanical and rheological properties of the various agricultural materials, but those properties are available mostly for foreign varieties of agricultural products. Rheological properties of rice seedlings become important to formulate the principles governing their mechanical behavior. The objectives of this study were to experimentally determine the creep and recovery behavior of rice seedlings of one japonica-type and one Indica x japonica hybrid in the transplanting age. The results of this study are summarized as follows; 1. The compression creep and recovery behavior of mat-type seedlings could be described by 4-element Burger's model. 2. The steady-state creep appeared at the stress larger than 0.8 MPa and the logarithmic creep appeared at the stress smaller than 0.8 MPa. 3. In the compression creep test of the rice seedlings, the instantaneous elastic modulus of Burger's model showed the range from 20 to 40 MPa. The higher value of absolute viscosity for the rice seedling explained that the rice seedlings were viscoelastic materials. 4. In the recovery test of the rice seedlings, there was a tendency that the higher permanent strain of all samples was observed under the smaller stress being appeared, and the larger permanent strain in Dongjin was observed than in Samkang.

• 치위생과학회지
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• 제10권6호
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• pp.459-464
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• 2010

본 연구는 실리콘 고무인상재의 보관온도에 따른 작업 시간과 압축 시 변형율, 탄성회복율, 점조도에 관한 물리적 특성에 대해서 평가하였으며, 다음과 같은 결과를 얻었다. 1. 작업시간은 저온의 온도유지장치에서 보관한 인상재가 실온이나 고온에서 보관한 인 상재보다 유의하게 크게 나타났고(P<0.05), 실온과 고온에서 보관한 인상재는 유의차 가 없었다. 2. 압축변형율은 저온 온도유지장치에서 보관한 인상재가 실온이나 고온에서 보관한 인 상재보다 유의하게 컸으며(P<0.05), 실온과 고온에서 보관한 인상재는 유의차가 없 었다. 3. 탄성회복율은 인상재를 보관한 각 저장온도에 따라 유의한 차이가 있는 것으로 나타 났으며(P<0.05), 온도가 높아짐에 따라 증가하였다. 4. 점조도는 인상재를 보관한 각 저장온도에 따라 유의한 차이가 있는 것으로 나타났으 며(P<0.05), 온도가 높아짐에 따라 감소하였다.

• 대한한의학회지
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• 제33권3호
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• pp.133-146
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• 2012

Background: Most antitumor agents have the side effect of chemotherapy-induced peripheral neuropathy (CIPN). Cancer patients who take antitumor agents suffer from CIPN, but there is no known treatment for it. Unlike the central nerve system, the peripheral nerve can self-repair, and the Schwann cell takes this mechanism. Objectives: In this study, we researched the effect of YideungJetong-Tang (YJT) extract on taxol-induced sciatic nerve damage, through in vitro and in vivo experiments. Also, we studied the effect of YJT extract on neurite recovery and anti-inflammatory effect after compression injury of sciatic nerve in vivo. Methods: Vehicle, taxol and taxol+YJT were respectively applied on sciatic nerve cells of rat in vitro, then the cells were cultured. The sciatic nerve cells and Schwann cells were then observed using Neurofilament 200, Hoechst, ${\beta}$ -tubulin, S-$100{\beta}$, caspase-3 and phospho-Erk1/2. CIPN was induced by taxol into the sciatic nerve of rat in vivo, then YJT extract was taken orally. The axons, Schwann cells and neurites of the DRG sensory nerve were then observed using Neurofilament 200, ${\beta}$-tubulin, Hoechst, S-$100{\beta}$, phospho-Erk1/2 and caspase-3. YJT was taken orally after sciatic nerve compression injury, and the changes in axon of the sciatic nerve, Schwann cells and TNF-${\alpha}$ concentration were observed. Results: The taxol and YJT treated group showed significant effects on Schwann cell recovery, neurite growth and recovery. In vivo, YJT compared with control group showed Schwann cell structural improvement and axons recovering effect after taxol-induced Schwann cell damage. After sciatic nerve compression injury, recovery of distal axon, changes of Schwann cell distribution, and anti-inflammatory response were observed in the YJT. Conclusions: Through this study, we found that after taxol-induced neurite damage of sciatic nerve in vivo and in vitro, YJT had significant effects on sciatic nerve growth and Schwann cell structural improvement. In vivo, YJT improved recovery of distal axons and Schwann cells and had an anti-inflammatory effect.