• 펄프종이기술
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• 제30권1호
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• pp.29-43
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• 1998

This study was to investigate the effect of .compressive load and cyclic humidity(2$0^{\circ}C$, 65% and 90% RH) on the physical and mechanical properties of corrugated board. Corrugated boards in the study were under compressive load and under cyclic humidity, and their properties were compared to those without load. Results were summarized as follows ; 1 Statistically significant correlation was shown between the ring crush of the boards and the compressive strength of cylinder specimen made from the boards. So we could study the compressive behavior of board with cylinder specimen. 2. The boards under the compressive load increased their moisture content and thickness much more than those without load both in constant and in cyclic RH. 3. The compressive and tensile strength of board samples were inversely and closely proportional to the sheet moisture content regardless of their load and humidity history. 4. The moisture content did not show any significant proportionality to the change of burst strength of boards within this experiment. 5. Board reconditioning in standard condition led to the recovery of the strength loss that had occurred under various load and humidity condition. 6. The handsheets prepared from the boards that had experienced compressive load and cyclic humidity, and those with no-load and 65% RH did not show any significant difference in strength properties. No physical damage or load-carrying properties of the wood fiber were observed by the compressive load and cyclic humidity history.

• 한방재활의학과학회지
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• 제26권4호
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• pp.9-21
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• 2016

Objectives This study is to review the effect of herbal medicine on treatment of sciatic nerve injury induced animal models reported in domestic & foreign journals. Methods 5 electronic databases (Pubmed, CAJ, RISS, Oasis, Koreantk) were searched with term as sciatic nerve injury, and animal study reports on sciatic nerve impairment with herbal medicine treatment were extracted. Results 31 articles were reviewd. All studies used SD rat. 26 studies used crush injury at the sciatic nerve using haemostatic forcep and 5 studies used sciatic nerve transection. 15 studies used single herb extract and 16 studies used complex herb medicine. Angelica gigantis radix was the most frequently used herb. Each study showed significant changes of improvement indicators from sciatic nerve impairment. Conclusions Various herb medicine are expected to have positive effects on sciatic nerve impairment.

• 한국식품저장유통학회지
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• 제6권3호
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• pp.303-307
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• 1999

온도 및 습도 변화에 따른 라이너원지의 압축강도 열화를 측정한 결과 압축강도는 온도변화에 영향이 없는 것으로 나타났다. 습도변화의 경우 66% RH에서는 IK원지의 강도저하가 가장 낮은 것으로 나타났다. 93% RH에서는 KA원지의 강도저하가 40%로 가장 낮았으며 SK원지가 56%로 가장 높게 나타났다. 비압축강도의 경우 66% RH에서는 SC 마니라와 IK 원지가, 93% RH에서는 IK원지와 KA원지가 가장 우수하였다. 원 단위 압축강도에서는 습도를 무시할 경우 SK원지가 우수하였으나 66% RH와 93% RH에서는 모두 KA원지가 다른 원지보다 우수한 것으로 나타났다. 따라서 농산물 포장용 라이너로 KA원지를 사용할 경우 경제적이면서도 압축강도가 높은 골판지상자를 제조할 수 있을 것으로 판단된다.

• Elastomers and Composites
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• 제51권1호
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• pp.24-30
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• 2016

Sole in the footwear usually modified with foaming agent on the polymer resin to improve the lightweightness and crush-cushion effect. In this study, we investigated rheological properties for polymer resin filled with the different type and concentration of foaming agent, capsule type foaming agent and organo-chemical foaming agent, under the time sweep test. Curing times of each polymer resin with different kind of foaming agent are delayed than reference material (epoxy resin with curing agent). In case of adding capsule type foaming agent, however, there is appropriate concentration to reduce the curing time, relatively. When foaming agent is activated, foaming force inflates the sample in contrast to condensation force of curing and then axial normal force develop to the (+) direction. Interestingly, by increase concentration of foaming agent, there is a specific point to break down the axial normal force development. The reason for this phenomenon is that coalescence of foams induce the blocking of axial normal force development.

• 설비공학논문집
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• 제12권10호
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• pp.932-940
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• 2000

An experimental study on evaporative heat transfer characteristics in micro-fin tubes before and after expansion process has been performed with R-22. Single-grooved micro-fin tubes with outer diameter of 9.52 mm were used as test sections, and it was uniformly heated by applying direct current to the test tubes. Experiments were conducted at mass flow rates of 20 and 30 kg/hr. For each mass flow rate condition, evaporation temperature was set at 5 and $15^{\circ}C$and heat flux was changed from 6 to 11 kW/$m^2$ The evaporative heat transfer coefficient of micro-fin tubes after expansion is decreased because of the crush of fins and enlargement of inner diameter compared to that before expansion. Convective boiling effect decreased remarkably at higher quality range in the micro-fin tube after expansion, and the difference of the heat transfer coefficient in micro-fin tubes before and after expansion was greater for higher quality region. The evaporative heat transfer coefficient of the micro-fin tube after expansion was 19.9% smaller on the average than that before expansion.

• Structural Engineering and Mechanics
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• 제78권1호
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• pp.31-39
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• 2021

To investigate numerically the effect of all parameters on the outcome of an aircraft impact into robust engineering structures like nuclear power plant containments is a tedious task. In order to reduce the problem to a manageable size, we propose a single dimensionless parameter, the damage potential, to characterize the main features of the impact. The damage potential, which is the ratio of the initial kinetic energy of the aircraft to the work required to crush it, enables us to find the crucial parameter settings that need to be modelled numerically in detail. We show in this paper that the damage potential is indeed the most important parameter of the impact that determines the time-dependent reaction force when either finite element (FE) modelling or the Riera model is applied. We find that parameters that do not alter the damage potential, like elasticity of the target, are of secondary importance and if parameters are altered in a way that the damage potential remains the same then the course of the impact remains similar. We show, however, that the maximum value of the reaction force can be higher in case of elastic targets than in case of rigid targets due to the vibration of the target. The difference between the Riera and FE model results is also found to depend on the damage potential.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1993년도 추계학술대회논문집
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• pp.243-251
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• 1993

With the recent issuance of a dynamic side impact test regulation in the Federal Motor Vehicle Safety Standard in the United States of America, many aspects of occupant protection in side impact crashes have been under investigation. Many investigations of real world accidents, crash test results and simulation studies have established that in side impact crashes of passenger cars, thoracic and pelvic injuries of occupant are, large part, caused by occupants' impact against the interior side of the vehicle, primarily the door. This paper is concerned with the development of a lumped mass computer model, which simulates the interaction of a struck car door and an adjacent seated occupant in side impacr, based CTP code which has been successfully used in vehicle and occupant simulation. New model developments include elimination of influence of vehicle side structure stiffness in the occupant injury responses. The model was used to investigated the effect of various door padding characteristics on occupant responses to improve vehicle safety performance. The evaluation of different crush properties of door padding have also focused to understand of behavior of impacted occupant. Results from simulations, The effects of both material coefficients $C_{f}$ and p were illustrated in terms of occupant injury criteria TTI and pelvis.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권5호
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• pp.375-395
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• 2006

Purpose: Lingual nerve (LN) damage may be caused by either tumor resection or injury such as wisdom tooth extraction, Although autologous nerve graft is sometimes used to repair the damaged nerve, it has the disadvantage of necessity of another operation for nerve harvesting. Moreover, the results of nerve grafting is not satisfactory. The nerve growth factor (NGF) is well-known to play a critical role in peripheral nerve regeneration and its local delivery to the injured nerve has been continuously tried to enhance nerve regeneration. However, its application has limitations like repeated administration due to short half life of 30 minutes and an in vivo delivery model must allow for direct and local delivery. The aim of this study was to construct a well-functioning $rhNGF-{\beta}$ adenovirus for the ultimate development of improved method to promote peripheral nerve regeneration with enhanced and extended secretion of hNGF from the injured nerve by injecting $rhNGF-{\beta}$ gene directly into crush-injured LN in rat model. Materials and Methods: $hNGF-{\beta}$ gene was prepared from fetal brain cDNA library and cloned into E1/E3 deleted adenoviral vector which contains green fluorescence protein (GFP) gene as a reporter. After large scale production and purification of $rhNGF-{\beta}$ adenovirus, transfection efficiency and its expression at various cells (primary cultured Schwann cells, HEK293 cells, Schwann cell lines, NIH3T3 and CRH cells) were evaluated by fluorescent microscopy, RT-PCR, ELISA, immunocytochemistry. Furthermore, the function of rhNGF-beta, which was secreted from various cells infected with $rhNGF-{\beta}$ adenovirus, was evaluated using neuritogenesis of PC-12 cells. For in vivo evaluation of efficacy of $rhNGF-{\beta}$ adenovirus, the LNs of 8-week old rats were exposed and crush-injured with a small hemostat for 10 seconds. After the injury, $rhNGF-{\beta}$ adenovirus($2{\mu}l,\;1.5{\times}10^{11}pfu$) or saline was administered into the crushed site in the experimental (n=24) and the control group (n=24), respectively. Sham operation of another group of rats (n=9) was performed without administration of either saline or adenovirus. The taste recovery and the change of fungiform papilla were studied at 1, 2, 3 and 4 weeks. Each of the 6 animals was tested with different solutions (0.1M NaCl, 0.1M sucrose, 0.01M QHCl, or 0.01M HCl) by two-bottle test paradigm and the number of papilla was counted using SEM picture of tongue dorsum. LN was explored at the same interval as taste study and evaluated electro-physiologically (peak voltage and nerve conduction velocity) and histomorphometrically (axon count, myelin thickness). Results: The recombinant adenovirus vector carrying $rhNGF-{\beta}$ was constructed and confirmed by restriction endonuclease analysis and DNA sequence analysis. GFP expression was observed in 90% of $rhNGF-{\beta}$ adenovirus infected cells compared with uninfected cells. Total mRNA isolated from $rhNGF-{\beta}$ adenovirus infected cells showed strong RT-PCR band, however uninfected or LacZ recombinant adenovirus infected cells did not. NGF quantification by ELISA showed a maximal release of $18865.4{\pm}310.9pg/ml$ NGF at the 4th day and stably continued till 14 days by $rhNGF-{\beta}$ adenovirus infected Schwann cells. PC-12 cells exposed to media with $rhNGF-{\beta}$ adenovirus infected Schwann cell revealed at the same level of neurite-extension as the commercial NGF did. $rhNGF-{\beta}$ adenovirus injected experimental groups in comparison to the control group exhibited different taste preference ratio. Salty, sweet and sour taste preference ratio were significantly different after 2 weeks from the beginning of the experiment, which were similar to the sham group, but not to the control group.

• Journal of Ginseng Research
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• 제27권3호
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• pp.103-109
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• 2003

실험적으로 좌골신경에 압궤손상을 유발한 흰쥐에 홍삼사포닌을 투여하여 손상된 말초신경의 회복에 미치는 홍삼사포닌의 효과를 광학현미경과 전자현미경적 관찰을 통한 조직ㆍ형태학적 평가를 실시한 결과 다음과 같은 결론을 얻었다. 1. 손상된 신경재생에 가장 유효한 홍삼사포닌의 농도를 확인하기 위하여 50 mg/kg, 100mg/kg, 150mg/kg의 홍삼사포닌을 3주간 투여한 결과 150 mg/kg의 홍삼사포닌이 가장 효과적이었다. 2. 홍삼사포닌이 신경재생에 미치는 영향을 알아보고자 150 mg/kg의 홍삼사포닌을 1주 간격으로 1주부터 3주까지 투여한 결과 총 유수신경섬유 수는 홍삼사포닌 투여군에서는 1주에서 2주 사이에 급격히 증가를 하고 3주에서는 약간 감소하는 경향을 나타내었으나 대조군에서는 1주에서 3주까지 꾸준히 증가하는 경향을 나타내었다. 총 유수신경섬유 수가 홍삼사포닌 투여군에 비하여 대조군이 현저히 적은 양이지만 증가하는 양상을 보이는 것은 축삭절단만 시키고 신경 연결을 완전히 절단하지 않았기 때문에 어느 정도 자연회복이 이루어지고 있음을 의미한다. 그러나 홍삼사포닌 투여군에서는 대조군 보다 많은 수의 유수신경섬유 수를 가지고 이로 인해 홍삼사포닌은 말초신경 손상 시 재생에 효과가 있음을 알 수 있다. 특히 홍삼사포닌 투여군에서 1주와 2주 사이에 큰 차이를 나타내는 것은 신경 재생의 초기 단계에 효과를 나타내는 것으로 생각된다. 이상의 결과를 종합하면 말초신경 손상 시 홍삼사포닌을 투여하는 것은 자연 회복의 속도를 촉진시키는 효과가 있으므로 신경손상 시 홍삼사포닌을 투여하는 방법을 임상에 적용한다면 조기에 신경재생을 유도할 수 있을 것이라고 사료된다.다.X>$_4$ ratio도 대조그룹 대비 RFEY-1.0, RFEY-3.0, RFEY-5.0의 투여그룹은 각각 39.5%, 67.3% 및 96.3%의 유의적인 증가효과가 인정되었다. 이상의 실험 결과를 종합해 볼 때 장미열매 추출물을 주재로 한 장미 요구르트의 항스트레스작용은 매우 효과적일 것으로 기대된다.cetate, jupinene, $\delta$-cadinene, germa acrene, farnesol 등이 검출되었고 원자방출검출기 (AED)를 이용하여 분석한 결과, 특이적인 황화합물 및 질소화합물 등이 검출되지 않았다.한 수술 전 평가 등을 통해 중장기 개통률을 향상시킬 수 있다.25^{\circ}C$에서 49.30% (76.66mg/kg)로 나타나 주로 $25^{\circ}C$ 이하에서 발현한 것으로 나타났다. 3. 배양온도에서 검지 된 뷰틸산의 량은 6일 동안 돈분에서 1,463.87mg/kg, 계분에서 96.72mg/kg, 우분에서 129.18mg/kg이 발현되었으며 돈분의 경우 93.31%(1,365.95mg/kg)가 $25^{\circ}C$에서 발현되었고 이 중 87.92%가 3일령, 4일령과 6일령에 집중적으로 나타났다. 계분의 경우 $37^{\circ}C$ 처리구에서 76.60%(74.09 mg/kg)로 발현되었고 이 중 88%가 1일령, 2일령과 5일령에 집중적으로 나타났다. 우분의 경우 61.55%(79.51mg/kg)가 $25^{\circ}C$에서 발현되었고 이 중 89.6%가 1일령, 3일령과 4일령에 집중적으로 나타났다. 4.

• Journal of the Korean Wood Science and Technology
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• 제28권1호
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• pp.71-79
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• 2000

산화전분을 골판지 구성원지인 표면라이너지와 이면라이너지에 각각 코팅하고 물성변화를 조사하였다. 산화전분 코팅에 의해 골판지 믈성과 관련된 각 라이너지의 물성이 개선되었고 링 크러시 강도의 경우 표면라이너지보다 이면라이너지에서 개선의 효과가 더욱 컸으며 도공하지 않은 경우에 비해 최대 19.7%의 증가를 보였다. 비교적 낮은 도공량으로도 파열지수는 증가하였으며 일정 수준의 도공량 이상에서는 더 이상 증가하지 않는 것으로 조사되었다. 파열강도가 증가함에 따라 링 크러시 강도도 증가하는 경향을 보였다. 표면라이너지, 이면라이너지 각각 1.41g/$m^2$, 1.58g/$m^2$의 도공량에 이를 때까지 TEA는 크게 증가하였으며 인장강도가 증가함에 따라 링 크러시 강도도 대체적으로 증가되었다. 낮은 도공량에서 stiffness가 증가하였으며 도공처리로 라이너지의 투기도는 감소하였지만 원지 간 결합에 장애를 일으킬 만큼의 염려는 없을 것으로 판단되었다.