• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1021-1025
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• 2009

A novel supramolecular network containing binuclear copper unit $[Cu(phen)_{2}({\mu}-ID\;A)Cu(phen){\cdot}(NO_{3})](NO_{3}){\cdot}4(H_{2}O)$ (1) was synthesized through the self-assembly of iminodiacetic acid ($H_2IDA$) and 1,10-phenanthroline (phen) in the condition of pH = 6. It has been characterized by the infrared (IR) spectroscopy, elemental analysis, single crystal X-ray diffraction, and thermogravimetric analysis (TGA). 1 shows a 2-D supramolecular structure assembled through strong and unique $\pi-\pi$ packing interactions. Density functional theory (DFT) calculations show that theoretical optimized structures can well reproduce the experimental structure. The TGA and powder X-ray diffraction (PXRD) curves indicate that the complex 1 can maintain the structural integrity even at the loss of free water molecules. The magnetic property is also reported in this paper.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.357-361
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• 1999

GOD electrochemically immobilized in PPy/GOD complex have an effect on redox properties of the complex. In the cyclicvoltammetry, GOD shows the redox reaction at the potential below -0.6Y vs. Ag/AgCI. That leads to new peaks in the cyclicvoltammograms in additional to typical PPy peaks. The pH of electrolyte solution during potential swing decreased to 4.4, and then increased to 10. That suggests the redox of GOD for the cycling. As the concentration of GOD was increased, the anodic wave of the new peaks was strong as much as increased. GOD obstructs the diffusion of electrolyte anion because of its net chain. Insulating property of GOD is cause that it made the faradic impedance of complex large in charge transfer. It suggests that increase of the concentration of GOD be against electrochemical coupling. Therefore, the concentration of GOD and electrochemical coupling should be dealt with each other. The apparent Michaelis-lenten constant ( K\`$_{M}$ ) was determined by 30.7 mmol d $m^{-3}$ fur the PPy/GOD complex. The value is of the same order of magnitude as that for soluble glucose oxidase from Aspergillus Niger.r.

• BMB Reports
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• v.41 no.8
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• pp.575-580
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• 2008

Thymocyte-specific transcriptional regulatory systems can be used to better understand the relationship between transcription and V(D)J recombination during early T cell development. In this study, we generated transgenic mice expressing the transactivator Gal4-VP16 or the Gal4 DNA binding domain (Gal4-DBD) under the control of the lck proximal promoter, which is only active in immature thymocytes. From these studies Gal4-VP16 and Gal4-DBD expression was shown to significantly alter thymic cellularity and differentiation without significantly changing the $CD3^+$ thymocyte distribution. Furthermore, the presence of Gal4-VP16 or Gal4-DBD in the transgenic thymocytes retarded the mobility of the Gal4 DNA binding motif as determined by a gel mobility shift assay, suggesting that the developmental alteration did not affect the functional property of the transgenic proteins. These results indicated that lck promoter-driven Gal4-VP16 or Gal4-DBD expression did not affect $CD3^+$ mature thymocytes, thus this system can be applied to study transcriptional regulation of transresponder genes in bigenic mouse model thymocytes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.149-152
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• 1997

High-power piezoelectric materials are being developed for applications such as actuators and ultrasonic motors. In this paper, ferroelectric property of iron-doped 0.57 (Sc$_{1}$2//Nb$_{1}$2/)O$_3$-0.43 PbTiO$_3$. which is the morphotropic phase boundary composition for the PSN-PT system, was investigated. The maximum dielectric constant ( $\varepsilon$$_{33}$/$\varepsilon$$_{0}$ = 2551) and the minimum dielectric loss(tan $\delta$ = 0.51 %) at room temperature were obtained at 01. wt% and 0.3 wt% of iron additions. With additions of the Fe$_2$O$_3$ the electromechanical coupling factor of radial mode k$_{p}$ and the piezoelectric coefficient d$_{33}$ were slightly decreased, on the other hand the mechanical quality factor was increased significantly. The highest mechanical quality factor (Qm= 297) was obtained at 0.3 wt% Fe$_2$O$_3$, which is 4.4 times larger than that of pure 0.57 PSN-0.43PT ceramics. The temperature dependence of the dielectric constant and dielectic loss was observed between 2$0^{\circ}C$ and 35$0^{\circ}C$ .X> .X> .

• Science of Emotion and Sensibility
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• v.15 no.3
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• pp.381-388
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• 2012

The purpose of this study is to check if LED lighting can be used as general lighting and examine the color rendering property of full color RGB LED lighting. CRI is one of the important properties of evaluating lighting. However the present CRI does not fully evaluate LED lightings. Firstly, the performance of a simple task was compared other than comparing CRI values for different lighting. For experimental preparation three types of lightings were used; standard D65 fluorescent tube, general household fluorescent tube, and RGB LED lighting. All three lightings show high error for Purple-Red. All three lightings show similar error for all hues and prove that color discrimination is not affected by the lighting. This proves that LED could be used as general lighting. Secondly, problems of the conventional CIE CRI method are considered and new models are suggested for the new lighting source. Each of the models was evaluated with visual experiment results obtained by the white light matching experiment. The suggested model is based on the CIE CRI method but replaces the color space model by CIELAB, color difference model by CIEDE2000, and chromatic adaptation model by CAT02.

• Wind and Structures
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• v.32 no.2
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• pp.115-126
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• 2021

The snow cornice mass on the formation zone had triggered avalanches which led to the loss of human life and property. Snow cornice is formed due to flow separation on the leeward side. Effect of lee slope is more prominent in the formation of snow cornices as compared to the windward slope. The analysis of wind flow pattern has been carried out to evaluate the performance of a jet roof. Computational Fluid Dynamics (CFD) analysis of wind flow over a 2D hill model was carried out using RNG based k-∈ turbulence models available in ANSYS Fluent. Effect of varying leeward hill slope (1:2 to 1:6) on flow separation for the given windward slope was observed and a critical slope of 1:4 was found at which the separation zone ceased to exist. The modification of wind flow over a hill due to the installation of jet roof was simulated. It was observed that jet roof had significantly modified the wind flow pattern around hill ridgeline and ultimately snow cornice formation had mitigated. The results of the wind flow pattern were validated with the wind data collected at the experimental site, Banihal Top (Jammu and Kashmir, India). The wind flow simulation over the hill and mitigation of cornice formation by the jet roof has been explained in the present paper.

• Food Science of Animal Resources
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• v.43 no.3
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• pp.540-551
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• 2023

Milk protein concentrate (MPC) is widely used to enhance the stability and texture of fermented dairy products. However, most research has focused on yogurt products, and the effects of MPC on sour cream characteristics remain unknown. Therefore, we investigated the effects of different MPC levels (0%, 1%, 2%, and 3% w/w) on the rheological, physicochemical, microbiological, and aroma characteristics of sour creams in this study. We found that MPC supplementation stimulated the growth of lactic acid bacteria (LAB) in sour creams, resulting in higher acidity than that in the control sample due to the lactic acid produced by LAB. Three aroma compounds, acetaldehyde, diacetyl, and acetoin, were detected in all sour cream samples. All sour creams showed shear-thinning behavior (n=0.41-0.50), and the addition of MPC led to an increase in the rheological parameters (η_a,50, K, G', and G"). In particular, sour cream with 3% MPC showed the best elastic property owing to the interaction between denatured whey protein and caseins. In addition, these protein interactions resulted in the formation of a gel network, which enhanced the water-holding capacity and improved the whey separation. These findings revealed that MPC can be used as a supplementary protein to improve the rheological and physicochemical characteristics of sour cream.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.10a
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• pp.54-54
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• 2003

DLC films were deposited on Si(100) substrates by inductively coupled plasma (ICP) assisted chemical vapor deposition (CVD). A mixture of acetylene (C$_2$H$_2$) and argon (Ar) gases was used as the precursor and plasma source, respectively. The structure of the films was characterized by the Raman spectroscopy. Results from the Raman spectroscopy analysis indicated that the property change of the DLC films is due to the sp$^3$ and sp$^2$ ratio in the films under various conditions such as ICP power, working pressure and RF substrate bias. The hydrogen content in the DLC films was determined by an electron recoil detector (ERB). The roughness of the films was measured by atomic force microscope (Am). A microhardness tester was used for the hardness and elastic modulus measurement. The DLC film showed a maximum hardness of 37㎬. In this work, the relationship between deposition parameters and mechanical properties were discussed.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.11
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• pp.64-72
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• 1996

This paper is aimed to develop an optical method for measuring 3-dimensional shapes of specular objects having curved surfaces. The existing methods measuring the shapes of specular objects have several common disadvantages: they may not work properly if the surface is highly specular like mirror surface or if the reflectance property is not uniform over the surface. And, they often require the a priori knowledege about the surface reflectance. To overcome these disadvantages, the measurement using double pass retroreflection method is proposed in this paper. For this measurement principle, an experimental measuring system is designed and prepared which is composed of a galvanometer scanner, a beam splitter, a laser source, a CCD camera, and a reflector made of retroreflective material. To verify the effectiveness of the measurement system a series of experiments are performaed for various specular objects. The results observed from the experiments show that the developed optical sensing system can be an effective mean of measuring the 3-D shapes of specular objects.

• Journal of Ocean Engineering and Technology
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• v.17 no.2
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• pp.47-53
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• 2003

The development of new materials with light weight and high strength has become vital to the machinery, aircraft and auto industries. However, there are a lot of problems with developing such materials that require such expensive tools, as well as a great deal of time and effort. Therefore, the improvement of fatigue life through, the adoption of residual stress, is the main focus. The compressive residual stress was imposed on the surface according to each shot velocity(1800, 2200, 2600, 3000rpm) based on Shot-peening, which is the method of improving fatigue life and strength. By using the methose mentioned above, we arrived at the following conclusions; 1. The fatigue crack growth rate(da/dN) of the Shot-peened material was lower than that of the Un-peened material. In stage I, $\Delta$K$_{th}$, the threshold stress intensity factor, of the shot-peen processed material is high in critical parts, unlike the Un-peened material. Also m, fatigue crack growth exponent and number of cycle of the Shot-peened material was higher than of the Un-peened material. That is concluded from effect of da/dN. 2. Fatigue life shows more improvement in the Shot-peened material than in the Un-peened material. Compressive residual stress of the surface on the Shot-peen processed operate resistance force of fatigue crack propagation.