• Korean Journal of Veterinary Research
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• v.38 no.1
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• pp.29-42
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• 1998

$Mg^{2+}$ is one of the most abundant divalent cations in mammalian body(0.2~1.0mM) and the important physiological roles are : first, the cofactor of many enzyme activities, second, the regulator of glycolysis and DNA synthesis, third, the important role of bioenergetics by regulating of phosphorylation, fourth, the influence of cardiac metabolism and function. In this work we have investigated the regulation of the $Mg^{2+}$ induced by ${\alpha}_1-adrenoceptor$ stimulation in perfused guinea pig hearts and isolated myocytes. The $Mg^{2+}$ content of the perfusate or the supernatant was measured by atomic absorbance spectrophotometry. The elimination of $Mg^{2+}$ in the medium increased the force of contraction of right ventricular papillary muscles, and the left ventricular pressure. Phenylephrine also enhanced the force of contraction in the presence of $Mg^{2+}-free$ medium. ${\alpha}_1-Agonists$ such as phenylephrine and methoxamine were found to induce $Mg^{2+}$ efflux in both perfused hearts and myocytes. These effects were blocked by prazosin, an ${\alpha}_1-adrenoceptor$ antagonist. The $Mg^{2+}$ influx could also be induced by phenylephrine and R59022, a diacylglycerol kinase inhibitor. In the presence of protein kinase C(PKC) inhibitors, phenylephrine produced an increase in $Mg^{2+}$ efflux from perfused hearts. Furthermore, $Mg^{2+}$ efflux by phenylephrine was amplified by phorbol 12-myristate 13-acetate(PMA). This enhancement of $Mg^{2+}$ efflux by PMA was blocked by prazosin in perfused hearts. By contrast, the $Mg^{2+}$ influx could be induced by verapamil, nifedipine, ryanodine in perfused hearts, but not in myocytes. $W^7$, a $Ca^{2+}$/calmodulin antagonist, completely blocked the phenylephrine-induced $Mg^{2+}$ efflux in perfused hearts. In conclusion, $Mg^{2+}$ is responsible for the cardiac activity associated with ${\alpha}_1-adrenoceptor$ stimulation. The mobilization of $Mg^{2+}$ is decreased or increased by ${\alpha}_1-adrenoceptor$ stimulation in guinea pig hearts. These responses may be related specifically to the respective pathways of signal transduction. A decrease in $Mg^{2+}$ efflux by ${\alpha}_1-adrenoceptor$ stimulation in hearts can be through PKC dependent and intracellular $Ca^{2+}$ levels.

• Journal of Environmental Science International
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• v.32 no.12
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• pp.899-914
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• 2023

Various seeding materials for cloud seeding are being used, and sodium chloride powder is one of them, which is commonly used. This study analyzed the experimental results of multi-aircraft cloud seeding in connection with Republic of Korea Air Force (CN235) and KMA/NIMS(Korea Meteorological Administration/National Institute of Meteorological Sciences) Atmospheric Research Aircraft. Powdered sodium chloride was used in CN235 for the first time in South Korea. The analysis of the cloud particle size distributions and radar reflectivity before and after cloud seeding showed that the growth efficiency of powdery seeding material in the cloud is slightly higher than that of hygroscopic flare composition in the distribution of number concentrations by cloud aerosol particle diameter (10 ~ 1000 ㎛). Considering the radar reflectivity, precipitation, and numerical model simulation, the enhanced precipitation due to cloud seeding was calculated to be a maximum of 3.7 mm for 6 hours. The simulated seeding effect area was about 3,695 km², which corresponds to 13,634,550 tons of water. In the precipitation component analysis, as a direct verification method, the ion equivalent concentrations (Na⁺, Cl^-, Ca²⁺) of the seeding material at the Bukgangneung site were found to be about 1000 times higher than those of other non-affected areas between about 1 and 2 hours after seeding. This study suggests the possibility of continuous multi-aircraft cloud seeding experiments to accumulate and increase the amount of precipitation enhancement.

• Journal of the Korean Society for Library and Information Science
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• v.48 no.3
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• pp.335-351
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• 2014

This study proposes a customized SNS operational strategy for special libraries based on a case study on the Ocean Science Library (OSL) of South Korea. The study conducted an in-depth analysis on an organizational structure, manpower, contents, and promotion. The outcome of SNS operational strategy deducted from this study can be categorized into several items, including: (1) a selection of an appropriate SNS channel, which meets the objective of the operation; (2) a formal division of works for SNS operation; (3) a designation of full-time managers and an establishment of a task force team; (4) a specialization of contents according to specific subjects; (5) on/off-line promotions focused on events, which encourage participations; (6) an improvement of contents through regular log analyses; and (7) a promotion of library website access through SNS, and so on. This research also suggested the strategies for the development of SNS operation: strengthening of communication and cooperation among librarians; distribution of academic and research outcomes of the umbrella organization; enhancement of a role as a communication channel between librarians and users, and carry out a role as a 'social curator.'

• Journal of ILASS-Korea
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• v.20 no.2
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• pp.65-69
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• 2015

In this study, the thermal performance of vehicle's cooling system is experimentally investigated using the water/coolant-based $Al_2O_3$ nanofluids as working fluids. For the purpose, the water/coolant-based $Al_2O_3$ nanofluids are prepared by twostep method with gum arabic. In order to obtain the well-suspended nanofluids, the agglomerated $Al_2O_3$ nanoparticles are precipitated using centrifugal force and the experiments are performed with supernatant of them. The thermal conductivity is measured by transient hot wire method and the thermal conductivity of nanofluids is enhanced up to 4.8% as compared to that of base fluids. Moreover, the cooling performance of water/coolant-based $Al_2O_3$ nanofluids is evaluated using vehicle's engine simulator under the constant RPM condition. The results show that the cooling performance of automobile engine increases up to 5.9% using prepared nanofluids. To investigate the effect of nanofluids on exhaust gas, the $NO_x$ emission is measured during the operation with respect to time and 10.3% of $NO_x$ emission is decreased. The experimental results imply that the water/coolant-based $Al_2O_3$ nanofluids might be used as a next-generation vehicles' coolant

• Journal of the Korean Geosynthetics Society
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• v.16 no.4
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• pp.221-230
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• 2017

We developed a polymer pouch using PVP that is water soluble in the precedent study. Yet melt viscosity was so low that it was not possible to produce hemispheric type which is essential for mass production, therefore we used another material to make the polymer pouch. It enabled to figure out a water-soluble transition and mechanic physical property of PEG that is newly chosen, and to blend the PEG with LLDPE and TALC followed by result. So, we could implement an evaluating property on blended proportion. It is important to find out a proper blending ratio throughout an experiment since its property is different or varied followed by each proportion as a water soluble character is conflict to a solid character. With the blending technique we were able to produce the polymer pouch enhanced for a tensile force and an impact intensity maintaining a water soluble character. We could identify a ground solidity effect of the polymer pouch as a result of a direct shear test using the product developed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.58-58
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• 2009

Uniformity related issues in chemical mechanical polishing (CMP) are within wafer non-uniformity (WIWNU), wafer to wafer non-uniformity (WTWNU), planarity and dishing/erosion. Here, the WIWNU that originates from spatial distribution of independent variables such as temperature, sliding distance, down force and material removal rate (MRR) during CMP, relies to spatial dependency. Among various sources of spatial irregularity, hardness and modulus of pad and surface roughness in sources for pad uniformity are great, especially. So, we investigated the spatial variation of pad surface characteristics using pad measuring system (PMS) and roughness measuring system. Reduced peak height ($R_{pk}$) of roughness parameter shows a strong correlation with the removal rate, and the distribution of relative sliding distance onwafer during polishing has an effect on the variation of $R_{pk}$ and WIWNU. Also, the results of pad wear profile thorough developed pad profiler well coincides with the kinematical simulation of conditioning, and it can contribute for the enhancement of WIWNU in CMP process.

• International Commerce and Information Review
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• v.14 no.3
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• pp.253-280
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• 2012

Since China reformed and opened up itself, processing trade system has enormously contributed to chinese economic development and also become driving force of chinese economic growth. However, due to imbalance of industrial distribution, overproduction of labor-intensive product has expanded, and as a result, mass export of low-value-added products has aggravated trade friction. Also, these low-value-added products has caused environmental pollution and brought resource waste. On this, Chinese government start to modify system according to strategy for enhancement of processing trade. In this study, as a countermeasure of the Change of Chinese processing trade system, applicability of the bonded area is suggested. Firstly, even if a company's item is applied to prohibited or restricted items, the company can trade if through the bonded area. Secondly, even if a company has duty of deposit reservation, the company can be exempt from duty of deposit reservation if through the bonded area. Thirdly, as to importing facilities for processing trade, a company can receive more benefit through the bonded area than through outside of the bonded area.

• JSTS:Journal of Semiconductor Technology and Science
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• v.10 no.3
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• pp.213-224
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• 2010

An optically controlled silicon MESFET (OPFET) was fabricated by diffusion process to enhance the quantum efficiency, which is the most important optoelectronic device performance usually affected by ion implantation process due to large number of process induced defects. The desired impurity distribution profile and the junction depth were obtained solely with diffusion, and etching processes monitored by atomic force microscope, spreading resistance profiling and C-V measurements. With this approach fabrication induced defects are reduced, leading to significantly improved performance. The fabricated OPFET devices showed proper I-V characteristics with desired pinch-off voltage and threshold voltage for normally-on devices. The peak photoresponsivity was obtained at 620 nm wavelength and the extracted external quantum efficiency from the photoresponse plot was found to be approximately 87.9%. This result is evidence of enhancement of device quantum efficiency fabricated by the diffusion process. It also supports the fact that the diffusion process is an extremely suitable process for fabrication of high performance optoelectronic devices. The maximum gain of OPFET at optical modulated signal was obtained at the frequency of 1 MHz with rise time and fall time approximately of 480 nS. The extracted transconductance shows the possible potential of device speed performance improvements for shorter gate length. The results support the use of a diffusion process for fabrication of high performance optoelectronic devices.

• The Journal of the Korea Contents Association
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• v.13 no.5
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• pp.58-70
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• 2013

This study focuses on the fact that intrinsic motivation which becomes the force to promote narrative is reinforced as a polyphonic structure through the psychodynamics of fear and desire internalized in a character, and from this perspective, it analyzes character rising strategies shown in Pixar's movie, . To verify fear and desire of a character, this study uses Enneagram personality types theory as the frame of analysis and reaches the following conclusions: (1) The main character, Carl's emotion originated from fear and desire was metaphorized as Muntz and Russell each, so the inside psychodynamics and the outer event visualizing it are set as contrapuntal composition. (2) However, inversely to the enhancement of Carl's polyphonicity, that excellent strategy works as the limit that restricts the psychodynamics of Muntz and Russell to a certain range. Lastly, it is expected that this study will be suggested as a sort of methodology about character rising strategies as turned into the database to which the result of follow-up research will be added, too.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1297-1303
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• 2020

In this study, nuclear radiation shielding and rigidity parameters of Y (0.1-x)B0.6Bi1.8O3La2x glassy system were investigated in order to determine it's suitability for use as nuclear radiation shielding materials. Therefore, a group of bismuth borate glass samples with La₂O₃ additive were synthesized using the technique of melt quenching. According to the results, the increase of the La₂O₃ additive increases the density of the glass samples and the mass attenuation coefficient (μ_m) values, whereas the half-value layer (HVL) and mean free path (MFP) values decrease. The effective atomic number (Z_eff) is also enhanced with an increment of both mass removal cross section for neutron (Σ_R) and absorption neutron scattering cross section (σ_abs). In addition to the other parameters, rigidity parameter values were theoretically examined. The increase of La₂O₃ causes some other important magnitudes to increase. These are the average crosslink density, the number of bonds per unit volume, as well as the stretching force constant values of these glass samples. These results are in concordance with the increase of elastic moduli in terms of the Makishima-Mackenzie model. This model showed an increase in the rigidity of the glass samples as a function of La₂O₃.