• Journal of Korean Society for Quality Management
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• v.38 no.2
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• pp.171-179
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• 2010

Pearn et al.(2002) supposed the $C_{pp}$ multiple process performance analysis chart. This chart displays multiple processes with the process variation and process departure on one single chart. But, this chart can not display the distribution of the process variation and process departure and is inappropriate for processes with non-normal distributions. With bootstrapping method, we can display the distribution of the process variation and process departure on the $C_{pp}$ multiple process performance analysis chart.

• The Plant Pathology Journal
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• v.35 no.6
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• pp.684-691
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• 2019

Evolution of adaptive mechanisms to abiotic stress is essential for plant growth and development. Plants adapt to stress conditions by activating the abscisic acid (ABA) signaling pathway. It has been suggested that the ABA receptor, clade A protein phosphatase, SnRK2 type kinase, and SLAC1 anion channel are important components of the ABA signaling pathway. In this study, we report that the shaker type potassium (K⁺) channel, GORK, modulates plant responses to ABA and abiotic stresses. Our results indicate that the full length of PP2CA is needed to interact with the GORK C-terminal region. We identified a loss of function allele in gork that displayed ABA-hyposensitive phenotype. gork and pp2ca mutants showed opposite responses to ABA in seed germination and seedling growth. Additionally, gork mutant was tolerant to the NaCl and mannitol treatments, whereas pp2ca mutant was sensitive to the NaCl and mannitol treatments. Thus, our results indicate that GORK enhances the sensitivity to ABA and negatively regulates the mechanisms involved in high salinity and osmotic stresses via PP2CA-mediated signals.

• Advances in concrete construction
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• v.11 no.2
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• pp.163-171
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• 2021

This paper studies the effect of using multi-scale reinforcement additives on mechanical strengths, damage performance, microstructure, and water absorption of cementitious composites. Small dosages of carbon nanotubes (CNTs) or polypropylene (PP) microfibers; 0.05%, 0.1%, and 0.2% by weight of cement; were added either separately or simultaneously into cement mortar. The experimental results show the ability of these additives to enhance the mechanical behavior of the mortar. The best improvement in compressive and flexural strengths of cement mortar reaches 28% in the case of adding a combination of 0.1% CNTs and 0.2% PP fibers for compression, and a combination of 0.2% CNTs and 0.2% PP fibers for flexure. Adding CNTs does not change the brittle mode of failure of plain mortar whereas the presence of PP fibers changes it into ductile failure and clearly enhances the fracture energy of the specimens. Scanning electron microscopic (SEM) images of the fracture surfaces highlights the role of CNTs in improving the adhesion between the PP fibers and the hydration products and thus enhance the ability of the fibers to mitigate cracks propagation and to enhance the mechanical performance of the mortar.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.4
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• pp.211-215
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• 2003

To examine the localization pattern of phospholipase D2 (PLD2) in the pancreatic islet (the islet of Langerhans) depending on species, we conducted a morphological experiment in the rat and guinea pig. Since individual islets display a typical topography with a central core of B cell mass and a peripheral boundary of A, D, and PP cells, double immunofluorescent staining with a panel of antibodies was performed to identify PLD2-immunoreactive cells in the islets PLD2 immunoreactivity was mainly present in A and PP cells of the rat pancreatic islets. And yet, in the guinea pig, PLD2 immunoreactivity was exclusively localized in A cells, and not in PP cells. These findings suggest a possibility that PLD2 is mainly located in A cells of rodent pancreatic islets, and that the existence of PLD2 in PP cells is not universal in all species. Based on these results, it is suggested that PLD2 may play a significant role in the function of A and/or PP cells via a PLD-mediated signaling pathway.

• BMB Reports
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• v.39 no.6
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• pp.671-676
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• 2006

The holoenzyme of protein phosphatase (PP) from tulip petals was purified by using hydrophobic interaction, anion exchange and microcystin affinity chromatography to analyze activity towards p-nitrophenyl phosphate (p-NPP). The catalytic subunit of PP was released from its endogenous regulatory subunits by ethanol precipitation and further purified. Both preparations were characterized by immunological and biochemical approaches to be PP2A. On SDS-PAGE, the final purified holoenzyme preparation showed three protein bands estimated at 38, 65, and 75 kDa while the free catalytic subunit preparation showed only the 38 kDa protein. In both preparations, the 38 kDa protein was identified immunologically as the catalytic subunit of PP2A by using a monoclonal antibody against the PP2A catalytic subunit. The final 623- and 748-fold purified holoenzyme and the free catalytic preparations, respectively, exhibited high sensitivity to inhibition by 1 nM okadaic acid when activity was measured with p-NPP. The holoenzyme displayed higher stimulation in the presence of ammonium sulfate than the free catalytic subunit did by protamine, thereby suggesting different enzymatic behaviors.

• Elastomers and Composites
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• v.44 no.2
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• pp.164-174
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• 2009

PA66/EPDM/PP-g-MA and PA66/EPDM-g-MA/PP-g-MA composites were manufactured by a modular intermeshing twin screw extruder for enhanced low temperature impact resistance with different content of PP-g-MA. The results showed that composite containing 90 wt% of PA66, 8 wt% of EPDM-g-MA, and 2 wt% of PP-g-MA has a optimum value in the thermal and mechanical properties. The characteristics of the composites were analyzed by TGA, DSC, and SEM. From above results, we established that the low interfacial strength and the impact resistance at low temperature shown in a pre-existing PP/EPDM composite were enhanced by grafting with compatibilizer such as maleic anhydride. These results show the possibility of local manufacturing process and cost down with optimum screw configuration for best mixing quality in the twin screw extruder.

• Electrical & Electronic Materials
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• v.9 no.10
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• pp.1033-1039
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• 1996

Electrical and mechanical properties of polymer sheet at cryogenic temperature have been investigated. Tensile stress(and strain at break) in liquid nitrogen(77K) of 79.7MPa(l.2%) and 117.4MPa(2.05%) are evaluated for films of Polypropylene (PP) and Kapton, respectively. Dielectric loss tangent(tan .delta.) of PP and Kapton films is almost independent of the frequency and tensile stress. Also, field strength of PP film at 77K decreases with increasing the tensile stress.

• Textile Coloration and Finishing
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• v.28 no.2
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• pp.101-108
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• 2016

Polypropylene(PP)/multiwalled carbon nanotubes(MWCNT) nanocomposites films and PP/poly(vinyl alcohol)/CNT nanocomposites films were prepared through melt mixing method by the extruder. The PP/CNT nanocomposites films, which contain CNT of a variable content, were prepared for the first time and research on a appropriate content of the CNT on the PP/CNT nanocomposites films was conducted. The effects of take-up speed of the extruder on the mechanical and chemical properties of the PP/CNT and PP/PVA/CNT nanocomposites film were studied. Field emission scanning electron microscope(FE-SEM) was used to examine the surface morphology and the DSC measurement and tensile test were conducted. It was found that the properties decreased when take-up speed was increased.

• Polymer(Korea)
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• v.39 no.2
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• pp.200-209
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• 2015

In this study, the influence of dilauroyl peroxide on mechanical and thermal properties of different polypropylene (PP) matrices was investigated. Polypropylene matrices, different molecular weight isotactic PP containing 0.01, 0.02, 0.04, 0.06, 0.08, and 0.1 wt% of dilauroyl peroxide (DLP) were prepared by using a single-screw extruder. The effect of the visbreaking agent (DLP) on mechanical, physical, thermal and morphological properties of different molecular weight PP had been studied. Mechanical properties (tensile strength at break point, at yield and elongation at break point), melt flow index (MFI), scanning electron microscope (SEM) and differential scanning calorimetric (DSC) analyses of these matrices were examined. Melting ($T_m$) and crystallization ($T_c$) temperatures, crystallinity ratio (%) and enthalpies were determined. The microstructure of isotactic polypropylene matrix was investigated by scanning electron microscopy (SEM). From SEM analysis, it was observed that the surface disorder increased by the increasing amount of DLP. As a result of DSC analyses, the crystallinity ratio of the PP matrices has varied between 1.64-7.27%. Mechanical properties of the matrices have been improved. Particularly, the mechanical tests of PP have given interesting results when compounded with 0.06-0.08 wt% dilauroyl peroxide (DLP). Mechanical properties and thermal decomposition processes were all changed by increasing the amount of DLP in the matrix structure.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.61-64
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• 2009

This study is reviewed fire resistance characteristics of high strength concrete according to changes in PP fiber mixing ratio and type of fine aggregate, and the results can be summarized as follows. As fire resistance characteristics, all plain crushed sands prevented spalling regardless of increase in mixing ratio of PP fiber. Mixtures other than the plain showed satisfactory spalling prevention when 0.05 % or more of PP fiber was mixed. After the fire resistance experiment, the plain showed 5.5 % of mass loss rate when fiber was not mixed and others could not be measured. According to increase in mixing ratio of fiber, river sand with fineness modulus of 2.2 showed most satisfactory result of 34 %${\sim}$42 %. Mass loss rate after fire resistance experiment was most satisfactory at about 10 % in the plain crushed sand without mixing of fiber, and all other mixes with 0.05 % PP fiber or more showed 5${\sim}$10 % loss rate.