• Journal of Pharmaceutical Investigation
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• v.39 no.4
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• pp.299-307
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• 2009

Data exclusivity is one of the most important intellectual property rights of pharmaceuticals. During data exclusivity period, third parties are prohibited from relying on the data which the original company has submitted to regulatory authority for drug application. I investigated data exclusivity systems for pharmaceuticals in the US, EU, Canada and Korea. New chemical entities were usually given the longest periods of data exclusivity compared to drugs with new indication or new formulation, although the protection periods varied by country. For new drugs to be entitled to a data exclusivity, strict conditions should be met. Data exclusivity has also been provided as an incentive to promote clinical investigation and drug development for pediatric population or orphan diseases. In Korea, data exclusivity was adopted in 1995 as an additive provision to "drug re-examination" which is to investigate post-marketing safety information of new drugs. It was introduced with few discussion on the purposes or effects of data exclusivity on pharmaceutical industry and pharmaceutical market in this country. I found that Korea's data exclusivity system falls short of considerations on valuing innovation of pharmaceutical research. It is necessary to improve data exclusivity system in order to promote innovative pharmaceutical development and to balance intellectual property rights protection and access to drugs in this country.

• Membrane Journal
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• v.22 no.3
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• pp.224-233
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• 2012

To improve permeation performance of gas separation membrane, polysulfone hollow fiber membrane was prepared by wet-dry phase inversion method using Triton X-100 as non-ionic additive. And variation of gas permeation behavior by additive was investigated. Various spinning conditions such as air gap, concentration of polymer, dope tank temperature were controlled and these effects were studied. The morphology and gas permeation property of hollow fiber membranes were investigated using scanning electron microscope (SEM) and bubble flow meter respectively. We confirmed that the membranes added with Triton X-100 had a smooth external skin at various air gap length conditions. The macrovoids of these hollow fiber membranes were more developed with increase of air-gap from 4 to 90 cm and that induced higher permeance. The permeance of polysulfone membranes has the higher value at comparatively lower concentration polymer (30 wt% polysulfone) and lower concentration of additive (15 wt% Triton X-100). When temperature in dope tank was controlled, the membranes prepared at $100^{\circ}C$ showed low permeance because of volatilization of additive and solvent.

• Applied Chemistry for Engineering
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• v.8 no.4
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• pp.640-644
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• 1997

We investigated that how both the type and the concentration of coal and the surfactant and the electrolyte added to increase the fluidity of CWM influence rheological characteristics. According to the type of coal, the viscosity of CWM was increased with increasing O/C ratio. Also, the CWM was represented the property of non-Newtonian fluid, having yield stress which was linerarly increased with increasing coal concentration. According to the surfactant used as an additive, the rheological characteristics of CWM was represented the pseudoplastic property as n<1 without relating to the concentration of added surfactants. Also, according to the increase of the amount of electrolyte, n was nearly approached 1. Therfore, we found that CWM opproched Newtonian fluid and that when more than 0.05wt.% of electrolyte were added, yield stress was not shown up.

• Journal of the Korean Applied Science and Technology
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• v.31 no.3
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• pp.486-491
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• 2014

We have been fabricated Thin-walled carbon nanotubes (TWNTs)/amine epoxy additives composite using Eco-friendly solvent system such as supercritical process and dry mixed process. TWNTs/amine epoxy additives composite has used as a curing agent for urethane based bisphenol A type epoxy resin. The thermo-mechanical property of the epoxy resin cured by TWNTs/amine epoxy additives composite is characterized by dynamic mechanical analysis(DMA) and dispersability of the nanotubes in the epoxy matrix is also confirmed by scanning electron microscope(SEM). As a results, the epoxy resin cured by TWNTs/amine epoxy additives composite with supercritical process shows enhanced dispersability of the TWNTs in the matrix and thermo-mechanical property when compare to dry mixed process.

• Communications of Mathematical Education
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• v.37 no.3
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• pp.419-442
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• 2023

This study investigated fifth graders' understanding of variables from a generalized arithmetic and a functional perspectives of early algebra. Specifically, regarding a generalized perspective, we included the property of 1, the commutative property of addition, the associative property of multiplication, and a problem context with indeterminate quantities. Regarding the functional perspective, we covered additive, multiplicative, squaring, and linear relationships. A total of 246 students from 11 schools participated in this study. The results showed that most students could find specific values for variables and understood that equations involving variables could be rewritten using different symbols. However, they struggled to generalize problem situations involving indeterminate quantities to equations with variables. They also tended to think that variables used in representing the property of 1 and the commutative property of addition could only be natural numbers, and about 25% of the students thought that variables were fixed to a single number. Based on these findings, this paper suggests implications for elementary school students' understanding and teaching of variables.

• Tribology and Lubricants
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• v.28 no.2
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• pp.81-92
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• 2012

To product multi-grade oil like engine oil, a sort of mineral base oil is mixed with a fundamental additive liquid package and a polymer liquid as viscosity index improver in order to improve the lubricating property of oil. That is, engine oil is the mixture of more than two fluids. In this paper, it will be systematically organized the governing equation describing non-Newtonian thermo-hydrodynamic lubrication related with the mixture of incompressible fluids based on the principle of continuum mechanics. Then, in order to find how the thermal analysis effect on the bearing performance lubricated with the mixture of multi-fluids, it will be compared to the performances between the mixture of each liquid to be blended and multi-grade engine oil as a single fluid in a high speed journal bearing. It is found that, in the case of lower viscosity oil, the difference of pressure distribution between the above two cases turns out to be existed, even if the load capacity is same level.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.5
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• pp.60-67
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• 2011

Hemicelluloses pre-extracted from Korean mixed wood chip were investigated as a wet-end additive. Hemicelluloses dissolved in hot water and alkali solution were isolated by ethyl alcohol precipitation from pre-extractives. They showed molecular weight of 9,000 ~ 27,000 g/mol as revealed by size exclusion chromatography. The reduction of molecular weight through hot water extraction was caused by autohydrolysis. Chemical composition of the hemicelluloses were analyzed with high-performance liquid chromatography and UV-Vis spectroscopy. As the surface charge of isolated hemicelluloses were negative, the adsorption of hemicelluloses onto softwood unbleached kraft pulp fiber was promoted by poly-DADMAC. The physical properties of handsheets increased as the molecular weight of hemicellulose increased. On the other hands, the optical property decreased with hemicellulose adsorption.

• Journal of Ocean Engineering and Technology
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• v.22 no.4
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• pp.46-50
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• 2008

Super duplex stainless steel has along life in severe environments because of its strength and corrosion resistance. If 0.2$\sim$0.3% Nitrogen in aninterstitial solid solution is added, the austenite structure is reinforced. This improves the solid solution hardening and the anticorrosionability. In this study, the mechanical properties and structures of the super duplex stainless steel with the 0.2% N additive were investigated to determine the effect of various volume fractions on the austenite phase. The various volume fractions and distributions of the austenite structure in the applied test specimens were obtained by changing the heat treatment temperature and cycle. The characteristics by amounts of the $\sigma$ phase obtained from the precipitation heat treatment were alsoinvestigated. From the results, when the austenite volume fraction increases, the tensile strength decreases and elongation increases. And the $\sigma$ phase was rapidly increased by increasing the heat treatment time. When the volume fraction of the $\sigma$ phase increased, tensile strength increased.

• Elastomers and Composites
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• v.51 no.3
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• pp.175-180
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• 2016

Influence of amino acidic chemical on properties of maleic anhydride-grafted ethylene-propylene-diene terpolymer/zinc oxide (EPDM-g-MAH/ZnO) composites was investigated. 4-Aminosalicylic acid (ASA), 4-amino-2-methoxybenzoic acid (AMBA), 12-aminolauric acid (ALA), and glutamine (Gln) were employed as the amino acidic chemicals. Though small quantity (0.5 phr) of the amino acidic chemical was added to the EPDM-g-MAH/ZnO composite, the properties were notably changed. By adding the amino acidic chemical, the percent crystallinity and apparent crosslink density were reduced. Order of the percent crystallinity was related to that of the $pK_a$ values of amino acidic chemicals. By adding the amino acidic chemical, the basic tensile properties were on the whole improved. The experimental results were explained by the $pK_a$ values of amino acidic chemicals, change of zinc ionomer formation, and interactions between the additive and EPDM-g-MAH chain.

• Journal of the Korean Ceramic Society
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• v.39 no.12
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• pp.1119-1123
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• 2002

Nanostructured spinel NiZn ferrites were prepared by the sol-gel method from metal nitrate raw materials. Analyses by X-ray diffraction and scanning electron microscopy showed the average particle size of NiZn ferrite was under 50 nm. The single phase of NiZn ferrites was obtained by firing at 250${\circ}C$, resulting in nanoparticles exhibiting normal ferrimagnetic behavior. The nanostructured $Ni_{1-X}Zn_XFe_2O_4$ (x=0.0∼1.0) were found to have the cubic spinel structure of which the lattice constants ${\alpha}_2$ increases linearly from 8.339 to 8.427 ${\AA}$ with increasing Zn content x, following Vegard's law, approximately. The saturation magnetization $M_s$ was 48 emu/g for x=0.4 and decreased to 8.0 emu/g for higher Zn contents suggesting the typical ferrimagnetism in mixed spinel ferrites. Pure NiZn ferrite phase substituted by Cu was observed before using the additive but hematite phase was partially appeared at $Ni_{0.2}Zn_{0.2}Cu_{0.6}Fe_2O_4$. On the other hand, the hematite phase in this NiZn Cu ferrite was disappeared after using the additive of acethyl aceton with small amount. The saturation magnetization Ms of $Ni_{0.2}Zn_{0.8-y}Cu_yFe_2O_4$(y=0.2∼0.6) as measured was about 51 emu/g at 77K and 19 emu/g at room temperature, respectively.