• Fibers and Polymers
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• 제5권1호
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• pp.19-24
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• 2004

PET yarns textured at different texturing conditions were treated with superheated steam or dry heat at different temperatures for different times. The effects of the treatment conditions on the thermomechanical and structural changes of the yarn were examined by shrinkage, X-ray diffraction and birefringence measurements. With increase in superheated steam temperature, the crystalline orientation factor and birefringence decreased, whereas crystal size increased. Dry heat treatment had a smaller effect on shrinkage and structural properties in comparison with superheated steam treatment. The additional shrinkage after texturing process was investigated. The effect of heat-setting in both media was more significant at $200^{\circ}C$. The time dependence of the properties was not linear.

• 대한본초학회지
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• 제32권5호
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• pp.39-46
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• 2017

Objective : This study was designed to evaluate the hypoglycemic effects of Helianthus tuberosi Rhizoma extracts and its optimum Heat processing conditions Methods : We investigated the Salivary ${\alpha}$-amylase, pancreas ${\alpha}$-amylase and ${\alpha}$-glucosidase inhibitory activities of extracts from Steam Heated Helianthus tuberosi Rhizoma Ext. The inhibitory activities of a 50% EtOH extract of Steam Heated Helianthus tuberosi Rhizoma Ext against ${\alpha}$-glucosidases were evaluated in this study. Inhibiting these enzymes involved in the absorption of disaccharides significantly decreases the postprandial increase in blood glucose level after a mixed carbohydrate diet. Furthermore, the postprandial blood glucose lowering effect of Steam Heated Helianthus tuberosi Rhizoma Ext. was compared to a known type 2 diabetes drug(Acarbose(R)) in a mice model. Steam Heated Helianthus tuberosus L. Ext significantly reduced the blood glucose increase after glucose loading. Results : The results were confirmed by real-time PCR that after treated with Streptozotocin in L6 cells, induced expression of GLUT4, after the steamed Helianthus tuberosus L. Ext. treated, observed its expression was increased. Steam Heated Helianthus tuberosus L Ext treated 4 hours in L6 cells, cytotoxicity was measured in MTT assay. Its toxicity were 5.7%, 9% and 11.3% at the treatment concentration $12.5{\mu}g/m{\ell}$, $25{\mu}g/m{\ell}$, the $50{\mu}g/m{\ell}$ respectively. Conclusions : Overall, the results of this study indicate that Hypoglycemic effect of Helianthus tuberosi Rhizoma caused by the Steam heat treatment, the optimum Heat processing condition is steamming at $121^{\circ}C$ for 30 min, and it will provide the basis for developing a useful dietary supplement for controlling postprandial hyperglycemia.

• 한국기계가공학회지
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• 제9권6호
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• pp.59-65
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• 2010

This study deals with the characteristic of refrigerant for heat-treatment deformation control of SCM415 steel. The control of heat-treatment deformation must need the progress of production parts for an industry machine. Most of the deformation is occurred on unequal cooling. The unequal cooling is occurred by a property of quenching refrigeration. When a heated metal is deposited in the refrigeration, the cooling speed is so slow in early period of cooling because of occurring a steam-curtain. After more cooling, the steam-curtain is destroyed. In this progress, the cooling speed is very fast. The object of this study is to control the deformation of heat-treatment for the part of the industry machine by improving the conditions of quenching. The cooling curves and cooling rates of water, oil and polymer solution are obtained and illustrated. From the characteristics of the quenching refrigerant, the effects of heat-treatments on the thermal deformation and fatigue strength are also investigated.

• Journal of Mechanical Science and Technology
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• 제16권5호
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• pp.647-654
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• 2002

This study deals with the characteristic of quenching refrigerant for heat treatment deformation control of SM45C steel. Heat-treatment deformation must be controlled for the progress of production parts for landing gear. Most of deformation is occurred on inconsistent cooling. The inconsistent cooling is caused by a property of quenching refrigerant. When a heated metal is deposited in the quenching refrigerant, the cooling speed is so slow in early period of cooling because of a steam-curtain. After additional cooling, the steam-curtain is destroyed. In this progress, the cooling speed is very fast. The object of this study is to control the deformation of heat-treatment for landing gear by improving the conditions of quenching. The cooling curves and cooling rates of water, oil and polymer solution are obtained and illustrated. From the characteristics of the quenching refrigerant, the effects of heat-treatments on thermal deformation and fatigue strength are also investigated.

• 열처리공학회지
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• 제13권5호
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• pp.330-336
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• 2000

This study deals with the characteristic of refrigerant for heat-treatment deformation control of SM45C steel. The control of heat-treatment deformation must need the progress of production parts for a landing gear. Most of the deformation is occurred on unequal cooling. The unequal cooling is occurred by a property of quenching refrigeration. When a heated metal is deposited in the refrigeration, the cooling speed is so slow in early period of cooling because of occurring a steam-curtain. After more cooling, the steam-curtain is destroyed. In this progress, the cooling speed is very fast. The object of this study is to control the deformation of heat-treatment for landing gear by improving the conditions of quenching. The cooling curves and cooling rates of water, oil and polymer solution are obtained and illustrated. From the characteristics of the quenching refrigerant, the effects of heat-treatments on thermal deformation and fatigue strength are also investigated.

• 한국수소및신에너지학회논문집
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• 제22권4호
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• pp.546-551
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• 2011

The corrosion on steam generator tubes of the secondary side of pressurized water reactor inhibits heat transfer. One of the most efficient techniques improving the heat transfer performance of a nuclear electric generation is a corrosion control. The environmental parameters mostly affecting corrosion are materials and chemical additives. It seems that no further corrosion occurs in steels with Polyacrylic acid polymer dispersant treatment. Polyacrylic acid forms a protective coating with uniform thickness on metal surface. Polyacrylic treatment appears to be the most convenient way to enhance the thermal performance by the thermal conductivity improvement in steam generators.

• 한국가구학회지
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• 제11권2호
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• pp.1-6
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• 2000

This study was carried out to investigate the effect of steaming on mechanical properties of heat-compressed wood specimens. The specimens for this mechanical strength tests were prepared to super-heated steam treatment after compression to the radial direction of sonamu (Pinus densiflora). The specimen's size is $50(L)mm{\times}20(R)mm{\times}17(T)mm$. Steaming temperature and treatment time is $120^{\circ}C$ and 20, 40, 60, 80, 100 minutes, respectively. Modulus of elasticity(MOE) in compressive test is directly proportional to steaming time. On the other hand, modulus of elasticity in bending test between steaming and not steaming after heat-compressed wood is similar irrespective of steaming time. The reason for this phenomenon is not clear yet.

• Journal of the Korean Wood Science and Technology
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• 제29권4호
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• pp.9-15
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• 2001

본 연구는 $100^{\circ}C$ 이상의 고온영역에서 증기처리에 의한 소나무(Pinus densiflora)재와 라디아타소나무(Pinus radiata)재의 전단강도를 조사하였다. 본 연구에서 사용한 열처리 조건은 온도조건 $100^{\circ}C$부터 $200^{\circ}C$까지 $20^{\circ}C$ 간격으로 6조건과 시간조건 5, 10, 20, 30분의 4조건이었으며, 폭쇄처리기를 사용하였다. 고온에서 증기처리에 의해 목재구성요소의 감소가 전단강도의 감소로 나타나고 목질재료의 광범위한 가소화를 진행시키는 것으로 판단된다. 목재의 전단강도는 증기처리시간에 따라서 점차적으로 감소한다는 것을 알 수 있었다. 10분 이상의 증기처리시간일 경우 온도가 올라갈수록 전단강도의 감소가 눈에 띄게 커졌다. 고온에서 증기처리에 의한 연화는 목재가공성 향상에 필요하다고 생각된다.

• 대한기계학회논문집B
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• 제24권7호
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• pp.994-1001
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• 2000

The dynamic behavior of a single-pressure heat recovery steam generator and turbine system for the combined cycle power plant is simulated on the basis of one-dimensional unsteady governing equations. A water level control and a turbine power control are also included in the calculation routine. Transient response of the system to the variation of gas turbine exit condition is simulated and effect of the turbine power control on the system response is examined. In addition, the effect of the treatment of inertia terms(fluid inertia and thermal inertia of heat exchanger metal) on the simulated transient response is investigated.

• Journal of Photoscience
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• 제8권1호
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• pp.19-22
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• 2001

It was reported that Red ginseng contains specific ginsenoside-Rg$_2$,-Rg$_3$,-Rh$_1$and -Rh$_2$, which show various pharmacological effects. However, production of these specific ginsenosides from Red ginseng is not commercially applicable because of high cost of the raw material, roots. This work was carried out to examine the production of Red ginseng specific ginsenosides from Agrobacterium-transformed hairy roots. Hairy roots were induced from 3 year-old root segment of Korean ginseng (Panax ginseng C.A. Meyer) after infection with Agrobacterium rhizogenes A4. Among many lines of hairybroots, KGHR-8A was selected. Steam heat treatment of hairy roots was resulted in the changes of ginsenoside composition. Eleven ginsenosides were detected in heat-treated hairy roots but eight in freeze dried hairy roots. In heat treated hairy root, content of ginsenoside-Rb$_1$,Rb$_2$,Rc, Rd, Re, Rf, and Rg$_1$were decreased compared to those of freeze dried hairy roots. However, heat treatment strongly enhanced the amount of Red ginseng specific ginsenogides (ginsenoside-Rg$_2$,-Rg$_3$,-Rh$_1$and -Rh$_2$). Amounts of ginsenoside-Rg$_3$,-Rh$_1$and -Rh$_2$ in heat-treated hairy roots were 2.58, 3.62 and 1.08 mg/g dry wt, respectively, but these were detected as trace amount in hairy roots without heat treatment. Optimum condition of heat treatment for the production of Red ginseng specific ginsenoside was 2 h at 105$^{\circ}C$. This result represents that Red ginseng specific ginsenoside can be producted from hairy roots by steam heat treatment.