• Applied Chemistry for Engineering
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• v.8 no.2
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• pp.320-331
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• 1997

ZSM-5 was crystallized at low temperature and atmospheric pressure using reflux unit. The overall molar composition used in this study was $7.83Na_2O-0.25Al_2O_3-100SiO_2-xTPABr-yH_2O$ where x is 1 and 3 mol, and y is 3000 mol, 3500 mol, and 4000 mol. $2^3$ factorial experiments were performed with the results of kinetics studies, showing $Na_2O$, TPABr, and $H_2O$ as main factors. The result suggested that the concentration of $H_2O$ is the most important. The morphology of final product was very uniform showing well-defined crystals with BET surface area of ca. $410m^2/g$.

• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.68-73
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• 2017

The removal of particulate matter ranging from $0.01{\mu}m{\sim}10{\mu}m$ can be performed by using membrane filters composed of fibers. Electrospinning techniques offer the production of very thin fibers with a uniform fiber diameter over conventional techniques including template synthesis, melt-blown, phase separation, etc. Air filtration will be improved with electrospun membranes due to the open pore structures, high porosity, and large surface area of the membranes. In the present study, filtration efficiency increased with pore size decrease and fiber density increase induced by carbon nanotube and the increased CA (cellulose acetate) concentration during electrospinning process.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.3
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• pp.321-328
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• 1999

Pulmonary blood vessels with diameters of $200{\sim}400\;{\mu}m$ produce considerably more force in response to vasoconstrictor drugs than those which are either smaller or larger. We have therefore investigated whether or not hypoxic pulmonary vasoconstriction (HPV) is more powerful in vessels of these diameters. We have also looked at the possibility that vessels from different regions of the lung respond differently. To do this we have grouped vessels according to their location within the lung as well as by size. We used a small vessel myograph (Cambustion AM10, Cambridge, UK) to study 208 preconstricted $(1\;{\mu}M\;PGF_{2{\alpha}})$ small pulmonary arteries $(300{\sim}800\;{\mu}m$ diameter when stretched to a tension equivalent to 25 mmHg transmural pressure) from 39 rats anaesthetized with 2% inspired halothane. A biphasic contraction was observed in response to hypoxia (ca. 25 mmHg $Po_2).$ The magnitudes of both the first, transient, phase (PT, peak tension) and of the second, sustained, phase (SST, steady state tension) were measured. The latter was measured 40 min after the start of hypoxia. The first phase was most pronounced in vessels with an average diameter of 423 ${\mu}m$ while the second phase was most pronounced in larger vessels (mean diameter 505 ${\mu}m).$ These maximal responses were all seen in vessels somewhat larger than reported by others. The responses of smaller vessels $(400{\sim}500\;{\mu}m)$ did not depend upon their location within the lung, but those of larger vessels $(600{\sim}700\;{\mu}m)$ showed regional differences. Those from the right lobe and those from the base of the lung gave the largest responses. It was especially noticeable that large vessels (631 ${\mu}m$ diameter) from the base of the right lung gave the biggest responses. Thus HPV seems to occur not in a uniform manner, dependent solely to the size of vessels, but it also depends to some degree on the region of the lung from which vessels have been taken. Furthermore, our results suggest that larger vessels, as well as smaller ones, may contribute significantly to HPV.

• Journal of Arbitration Studies
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• v.13 no.2
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• pp.519-546
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• 2004

On June 27, 2002 Canadian Internet Registration Authority (CIRA) launched dot-ca domain name dispute resolution service through BCICAC and Resolution Canada, Inc. The Domain name Dispute Resolution Policy (CDRP) of CIRA is basically modelled after Uniform Domain Name Dispute Resolution Policy(UDRP), while the substance of CDRP is slightly modified to meet the need of Canadian domain name regime and its legal system. Firstly, this article examined CIRA's domain name dispute resolution policy in general. It is obvious that the domain name dispute resolution proceeding is non-binding arbitration to which arbitration law does not apply. However it still belongs to the arbitration and far from the usual mediation process. Domain name arbitrators render decision rather than assist disputing parties themselves reach to agreement. In this respect the domain name arbitration is similar to arbitration or litigation rather than mediation. Secondly it explored how the panels applied the substantive standards in domain name arbitration. There is some criticism that panelists interprets the test of "confusingly similar" in conflicting manner. As a result critics assert that courts' judicial review is necessary to reduce the conflicting interpretation on the test of substantive standards stipulated in paragraph 3 of CDRP. Finally, it analysed the court's position on domain name arbitral award. Canadian courts do not seem to establish a explicit standard for judicial review over it yet. However, in Black v. Molson case Ontario Superior Court applied the UDRP rules in examining the WIPO panel's decision, while US courts often apply domestic patent law and ACPA(Anticyber -squatting Consumer's Protection Act) to review domain name arbitration decision rather than UDRP rules. In conclusion this article suggests that courts should restrict their judicial review on domain name administrative panel's decision at best. This will lead to facilitating the use of ADR in domain name dispute resolution and reducing the burden of courts' dockets.

• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.185-190
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• 2016

Background: In order to measure neutron energy spectra, the conventional Bonner Sphere Spectrometers (BSS) are widely used. In this spectrometer, several measurements with different size Bonner spheres are required. Operators should, therefore, place these spheres in several times to a measurement point where radiation dose might be relatively high. In order to reduce this effort, novel neutron energy spectrometer using an onion-like single Bonner sphere was proposed in our group. This Bonner sphere has multiple sensitive spherical shell layers in the single sphere. In this spectrometer, a band-shaped thermal neutron detection medium, which consists of a LiF-ZnS mixed powder scintillator sheet and a wavelength-shifting (WLS) fiber readout, was looped to each sphere at equal angular intervals. Amount of LiF neutron converter is reduced near polar region, where the band-shaped detectors are concentrated, in order to uniform the directional sensitivity. The LiF-ZnS mixed powder has an advantage of extremely high light yield. However, since it is opaque, scintillation photons cannot be collect uniformly. This type of detector shows no characteristic shape in the pulse height spectrum. Subsequently, it is difficult to set the pulse height discrimination level. This issue causes sensitivity fluctuation due to gain instability of photodetectors and/or electric modules. Materials and Methods: In order to solve this problem, we propose to replace the LiF-ZnS mixed powder into a flexible and Transparent RUbber SheeT type $LiCaAlF_6$ (TRUST LiCAF) scintillator. TRUST LiCAF scintillator can show a peak shape corresponding to neutron absorption events in the pulse height spectrum. Results and Discussion: We fabricated the prototype detector with five sensitive layers using TRUST LiCAF scintillator and conducted basic experiments to evaluate the directional uniformity of the sensitivity. Conclusion: The fabricated detector shows excellent directional uniformity of the neutron sensitivity.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.470-475
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• 2013

Zr-benzendicarboxylate structure, UiO-66 was prepared in 1-L batch scale by using a unique sonochemical-solvothermal combined synthesis method. The produced UiO-66 showed uniform particles of ca. $0.2{\mu}m$ in size with the BET surface area of $1,375m^2/g$ in high product yield (>95%). The UiO-66 showed 198 and 84 mg/g $CO_2$ adsorption capacity at 273 K and 298 K, respectively, with excellent $CO_2$ selectivity ($CO_2:N_2=32:1$) at ambient conditions. The isosteric heat of $CO_2$ adsorption varied from 33 to 25 kJ/mol as the adsorption progressed. The UiO-66 tested for xylene isomer separation in a liquid-phase batch mode confirmed preferential adsorption of the adsorbent for o-xylene over m-, and p-xylene.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.56-60
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• 2018

There have been a lot of study to improve the performance of membrane filters as the removal of particulate matter has been of great interest due to the negative effects. Among the membrane fabrication techniques, the electrospinning technique is the most promising because it can produce uniform fibers ranging from nano to micrometer size. The electrospun membranes will greatly improve the filtration performance due to the high ratio of surface area to volume and the high porosity. In the present study, polystyrene (PS) and cellulose acetate (CA) polymers were used to produce the membranes with carbon nanotube (CNT), showing the filtration performances were improved with the optimal amounts of CNT.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.1
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• pp.1-8
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• 2000

To investigate the contributions of intrinsic membrane properties to the spontaneous activity of medial vestibular nucleus (MVN) neurons, we assessed the effects of blocking large and small calcium-activated potassium channels by means of patch clamp recordings. Almost all the MVN neurons recorded in neonatal $(P13{\sim}P17)$ rat were shown to have either a single deep after-hyperpolarization (AHP; type A cells), or an early fast and a delayed slow AHP (type B cells). Among the recorded MVN cells, immature action potential shapes were found. Immature type A cell showed single uniform AHP and immature B cell showed a lack of the early fast AHP, and the delayed AHP was separated from the repolarization phase of the spike by a period of isopotentiality. Application of apamin and charybdotoxin (CTX), which selectively block the small and large calcium-activated potassium channels, respectively, resulted in significant changes in spontaneous firings. In both type A and type B cells, CTX (20 nM) resulted in a significant increase in spike frequency but did not induce bursting activity. By contrast, apamin (300 nM) selectively abolished the delayed slow AHP and induced bursting activity in type B cells. Apamin had no effect on the spike frequency of type A cells. These data suggest that there are differential roles of apamin and CTX sensitive potassium conductances in spontaneous firing patterns of MVN neurons, and these conductances are important in regulating the intrinsic rhythmicity and excitability.

• Economic and Environmental Geology
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• v.18 no.2
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• pp.139-150
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• 1985

Skarn at the Dielette formed largely in calc-silicate hornfels at the contact with the Flamanville granite. The skarn consists mainly of garnet and pyroxene, and less frequently vesuvianite. Traversing toward calc-silicate hornfels wall rock from a central zone of the skarn, the general sequence of formation of mineral assemblages is: (1) dark brown garnet (2) pale brown garnet-vesuvianite-pyroxene, and (3) pyroxene-prehnite-scapolite-wollastonite envelopes (designated as transition zone) developed between skarn and calc-silicate hornfels. The central zone of the skarn consists mainly of dark brown garnets (garnet I) that contain little or no pyroxene. The pale brown garnet (garnet II) is associated with pyroxene and vesuvianite. The sequence of these garnets results from the zonal growth outward. There is an abrupt discontinuity in composition between garnet I formed in early stage and garnet II in late stage, while each garnet shows relatively uniform composition. At the zone in contact with the granite, the iron contents of garnets decrease toward the marginal zone of the skarn, from an average value of 36 mole % andradite in garnet I to 18 mole % andradite in garnet II. At the zone distant from the granite, the andradite component decreases from 28 mole % in garnet 1 to 19 mole % in garnet II. The variation of the iron contents of pyroxenes is also similar to that of garnets. The sharp discontinuity in composition of garnets and pyroxenes suggests that the skarn of study area was formed by infiltration metasomatic process. The results of the analyses of mineral assemblages of the transition zone by chemical potential diagrams suggest that the transition zone was made by the diffusion of the elements Ca, K and Fe from the skarn to the calc-silicate hornfels contact zone. The estimated temperatures and $Xco_2$ for the formation of the transition zone show $300^{\circ}C$$440^{\circ}C$ and $0.07{\pm}0.05<Xco_2<0.02{\pm}0.01$ at 1 Kb respectively.

• Applied Chemistry for Engineering
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• v.34 no.2
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• pp.121-125
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• 2023

Casein is a milk protein and one of the most important nutrients in milk. The composition is over 80% in cow's milk and about 20~45% in human's milk. Casein is highly biocompatible and biodegradable, so it has been studied for various biomedical materials applications as well as drug delivery systems. It is widely known that casein can be prepared as nanoparticles in the presence of the Ca²⁺ metal ion. Because casein is amphiphilic, hydrophobic drugs could be loaded inside to form a protein-based drug delivery system. In this study, we studied the optimum conditions for casein nanoparticle formation using natural metal ions present in the body, such as calcium, magnesium, zinc, and iron. It was confirmed that nanoparticles have a uniform size of around 150 nm and negative zeta potential values. In addition, it was demonstrated that casein nanoparticles have a cell viability of more than 80% and efficient intracellular uptake properties using confocal microscopy. From the results, it was also shown that the casein nanoparticles prepared using various metal ions have the potential to be biocompatible drug delivery carriers.