• Elastomers and Composites
• /
• v.37 no.2
• /
• pp.79-85
• /
• 2002

Ethyl-branched polyethylene [PE(2)] containing 2mole% ethyl branch and three ethylene-propylene rubbers (EPR's) having the same ethylene(E)-propylene(P) molar ratio(E/P=50/50) with different stereoregularity, that is, random EPR (r-EPR), alternating-EPR (alt-EPR) and isotactic-alternating-EPR (iso-alt-EPR) were mixed for the investigation or their properties depending on the stereoregularity. Crystallinity of the prepared blends decreased with increasing content of amorphous EPR because of a decrease in both the degree of annealing and kinetics of diffusion of the crystallizable polymer content. With blend composition, crystallinity was reduced with the stereoregularity in EPR. The thermodynamic interaction parameter(x) for the three blend systems approximately equals to zero near the melting point. These systems were determined to be miscible on a molecular scale near or above the crystalline melting point or the crystalline PE(2). From the measurement of $T_m$ vs. $T_c$, the behavior of PE(2) is mainly due to a diluent effect of EPR component. The spherulite size measured by small angle light scattering (SALS) technique depended upon blend composition, and stereoregularity of EPR. The size of spherulite was enlarged with the content of rubbery EPR and the decrease of stereoregularity in EPR.

• Journal of Radiation Protection and Research
• /
• v.38 no.4
• /
• pp.185-188
• /
• 2013

Heating method using electric heater was used to reduce water content in fingernail clippings. Authors found that low water content is helpful to measure EPR signal of fingernail sample with enhanced variability. Generally, natural dehydration happens in normal room condition at least one month and needs much time for using in experiment. So, artificial heating method is applied in this study for time savings. Fingernail samples were tested to find effect of water content to the EPR signal on microwave power levels for dosimetry. Low water content in fingernail reduced variability of EPR signal and makes it possible to measure accurate EPR signal. It also made it possible to measure constant movement of EPR signals on several microwave power levels. Although this method was difficult to apply directly in fingernail/EPR dosimetry, we, authors, believe that this heating method would be useful to differentiate MIS2 and RIS which are generally located at the same g-factor and almost impossible to be identified with each other.

• Elastomers and Composites
• /
• v.36 no.3
• /
• pp.169-176
• /
• 2001

Ethyl-branched polyethylene[PE(2)] containing 2mole% ethyl branch and three ethylene-propylene rubbers(EPR's) haying the same ethylene(E)-propylene(P) molar ratio(E/P=50/50) with different stereoregularity, that is, random EPR(r-EPR), alternating-EPR(alt-FPR) and isotactic-alternating-EPR(iso-alt-EPR) were mixed for the investigation of their properties depending on the stereoregurarity. The three blends were immiscible at room temperature, and showed the simple additivity effect in density behavior. The melting point depression with blend composition increased in order of PE(2)/r-EPR>PE(2)/alt-EPR>PE(2)/iso-alt-EPR. In the tensile test, this blend systems have the lowest value or the breaking strength at FE(2) fraction of 0.5. This phenomenon results from the greastest separated phase morphology at this blend composition.

• The Korea Journal of Herbology
• /
• v.20 no.2
• /
• pp.159-169
• /
• 2005

Objectives : This study was carried out for the purpose of knowing the effect from anti-arthma action of the abstraction from a extract of Paridis Rhizoma(EPR). In order to know what the effect of controlling an abstraction from Paridis Rhizoma. and about the expression of B cells and Ig E cells, mast cells it was necessary for it to be activated by ovalbumin. Methods : In order to know what the effect was on the organization of cytokine gene expression from The increase and divorce of the B cells and allergic acting by EPR, we found it necessary to examine the BALF. At the same time, as we examined the histamine release by ELISA method, we also examined the effect of EPR. Results : EPR at $100\;{\mu}g/ml$, the highest concentration examined did not have any cytotoxic effects on mLFCs. In FACS analysis, number of granulocyte/lymphocyte, $CD3e^+/CCR3^+,\;CD4^+\;and\;CD23^+/B220^+$ in asthma-induced lung cells were significantly decreased by EPR treatment compared to the control group. In RT-PCR analysis, mRNA expression for CCR3, eotaxin and histamine in asthma-induced lung cells, which was induced by rIL-3 plus rmIL-5 treatments, was significantly decreased by EPR treatment. In ELISA analysis, production levels of IL-4, IL-13 and histamine in asthma-induced lung cells, which were induced by rIL-3 plus rmIL-5 co-treatment, were significantly decreased by EPR treatment. EPR treatments significantly inhibited the proliferation of eosinohils prepared from asthma-induced mouse lung tissues compared to the non-EPR treated control cells. Immunohistochemical analysis revealed that EPR treatment significantly decreased the levels of eosipnphil activation compared to non-treated cells. Conclusion : The present data suggested that Paridis Rhizoma may have an effects on the inhibition of parameters associated with asthma responses in eosinpophils, and thus implicate the possibility for the clinical application of Paridis Rhizoma.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.31 no.3
• /
• pp.167-172
• /
• 2017

In this study, we investigated the effect of Puerariae Radix ethanol extracts (EPR). The effect of the EPR on proliferation of human hair dermal papilla cells(HHDPCs) by MTT assay and observed Expression of mechanisms that regulate cell proliferation extracellular signal-regulated kinase(ERK) and Akt by western blot. The results showed EPR increased the proliferation of HHDPCs and up-regulation phosphorylation of ERK and Akt. ERK and Akt increased by EPR inhibited phosphorylation by PD98059 (ERK inhibitor) and LY294002 (Akt inhibitor), and cell proliferation was also inhibited. These results suggested EPR increases the proliferation of HHDPCs through phosphorylation of ERK and Akt, and therefore is a beneficial effect for the alopecia treatment.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.13 no.3
• /
• pp.1-8
• /
• 2009

This thesis has analyzed the effect of the surge happening in flight on the engine performance, especially on the PW4000 turbofan engine. It is to be judged that the flight surge can occur more often at the time of takeoff than it does en route due to the fact that the engine parameters are prone to fluctuate. EPR is judged to be the most highly sensitive parameter responding when surge occurs. Both Engine rpm and Wf decrease almost simultaneously just like an EPR. During the take-off rolling, N1 vibration is more sensitive than the N2 vibration. Consequently, the surge can be detected by EGT increase, while the other parameters (EPR, rpm, Wf, etc) decrease.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.05a
• /
• pp.236-239
• /
• 2008

This thesis has analyzed the effect of the surge happening in flight on the engine performance of the PW4000 turbofan engine. EPR is judged to be the most highly sensitive parameter responding when surge occurs. Both N1 rpm and N2 rpm decreases almost simultaneously just like an EPR. During the take-off rolling, the N1 vibration is more sensitive than the N2 vibration. Consequently, the surge can be detected by EGT increase, while the other parameters decrease.

• Journal of the Korean Chemical Society
• /
• v.47 no.4
• /
• pp.432-436
• /
• 2003

• Journal of the Korean Magnetic Resonance Society
• /
• v.5 no.1
• /
• pp.13-18
• /
• 2001

Natural alpha radiation produced a stable defect center to certain minerals. Electron Paramagnetic Resonance(EPR) spectroscopy is a powerful tool f3r quantifying this defect center. EPR method has been applied to trace alpha-radiation effect around the uranium ore deposit. The results show that EPR technique can be used to measure rapidly and nondestructively the defect center produced by natural alpha radiation. In general, a good correlation was achieved between defect center concentration and actinide elements(U, Th). These results imply that the concentration of defect center is dependent on the alpha radiation dose over long time scale.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07a
• /
• pp.432-435
• /
• 2003

최근 초고압 케이블 절연체로 XLPE(가교 폴리에틸렌)이 널리 사용되어 지면서 XLPE의 여러 물리 화학적 특성에 따른 절연 성능에 관한 연구가 활발히 이루어지고 있다. 이러한 XLPE 절연층은 제조과정에서 압출과정을 거쳐 도체를 감싸게 되는데 이 과정에서 흐름 패턴으로 나타나는 비등방성(anisotropy)을 띠게된다. 본 논문에서는 초고압 XLPE 케이블에서 시계 방향으로 나타나는 비등방성(anisotropy)이 나타내는 기계-전기적 특성을 인장강도(tensile strength), 트리 개시전압 및 개시시간을 측정한 결과를 토대로 고찰해 보았으며, 이러한 비등방성이 초고압 XLPE 케이블의 절연 성능에 영향을 주는 인자로 고려되어야 함을 알 수 있었다.