• Journal of the Korean Ceramic Society
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• v.43 no.12 s.295
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• pp.768-774
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• 2006

The microstructure of Ni-YSZ cermets was controlled with fine and coarse starting powders (NiO and YSZ) to obtain a optimum strong and conductive tubular anode support for SOFCs. Three types of cermets with different microstructures, i.e., coarse Ni-fine YSZ, fine Ni-coarse YSZ, and fine Ni-fine YSZ, were fabricated to investigate their electrical and mechanical properties. The cermets from fine NiO powder showed high electrical conductivity due to the enhanced percolation of Ni particles. The cermet by foe Ni and coarse YSZ showed excellent electrical conductivity (>1000 S/cm) despite its high porosity $(\sim40%)$ but it showed poor mechanical strength due to the lack of percolation by YSZ particles and due to large pores. Thus fine NiO and YSZ powders were used to make strong and conductive Ni-YSZ support tube by extrusion. The microstructure of the anode tube was modified by the amount of polymeric additives and carbon black, a pore former. Ni-YSZ tube (porosity $\sim34%$) with the finer microstructure showed better performance both in electrical conductivity (>1000 S/cm) and fracture strength $(\sim140\;MPa)$. Either flat or circular NiO-YSZ tubes with the length from 20 to 40cm were successfully fabricated with the optimized composition of materials and polymeric additives.

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.881-886
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• 2010

A novel Schiff base N-(2,4-dinitro-phenyl)-N'-(1-phenyl-ethylidene)-hydrazine has been synthesized and structurally characterized by X-ray single crystal diffraction, elemental analysis, IR spectra and UV-vis spectrum. The crystal belongs to monoclinic with space group P21/n. The molecules are connected via intermolecular O-$H{\cdots}O$ hydrogen bonds into 1D infinite chains. The crystal structure is consolidated by the intramolecular N-$H{\cdots}O$ hydrogen bonds. weak intermolecular C-$H{\cdots}O$ hydrogen bonds link the molecules into intriguing 3D framework. Furthermore, Density functional theory (DFT) calculations of the structure, stabilities, orbital energies, composition characteristics of some frontier molecular orbitals and Mulliken charge distributions of the title compound were performed by means of Gaussian 03W package and taking B3LYP/6-31G(d) basis set. The time-dependent DFT calculations have been employed to calculate the electronic spectrum of the title compound, and the UV-vis spectra has been discussed on this basis. The results show that DFT method at B3LYP/6-31G(d) level can well reproduce the structure of the title compound.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.6
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• pp.1267-1272
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• 2009

The purpose of this study is to survey the importance of items for the physiological and pathological symptoms for estimating a health condition according to Sasang constitution to establish the SHI(Sasangin Health Index) which will reflect the concept of inherent vitality. We surveyed expert opinion with questionnaires from 20 Sasang constitution specialists. The questionnaire was composed of 57 items on physiological and pathological symptoms and specialist opinions. Each item was marked from A to E according to importance in evaluating health state in each constitution, and if the mean score of an item was over 3.0, the item was regarded as important. Important indexes among physiological symptoms were diet, digestion condition, perspiration condition, frequency of defecation, heat and cold response, and temperature of drinking water in Soeumin, pathologic perspiration and defecation condition in Soyangin, repast, perspiration condition, and the amount of drinking water in Taeeumin, and urination frequency in Taeyangin. Important indexes among pathological symptoms were sighing, indigestion, and abdominal pain in Soeumin, oral condition, chest distress, brash, and amnesia in Soyangin, eye condition, palpitation, and edema in Taeeumin, and vomiting and incapacity of the lower limbs in Taeyangin. There are different health evaluating index and priority order in it according to Sasang constitution.

• Journal of Microbiology and Biotechnology
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• v.26 no.6
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• pp.1046-1056
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• 2016

RV-23 is a melittin-related antibacterial peptide (MRP) with lower cytotoxicity than either melittin or AR-23, another MRP. The aim of this study was to explore the mechanism of RV-23's antibacterial selectivity and its hemocompatibility. The results showed that all the peptides exhibited lytic activity against Staphylococcus aureus and Escherichia coli, with RV-23 showing the highest potency. Moreover, RV-23 had lower cytotoxicity than melittin or AR-23 at their minimal inhibitory concentration. In addition, CD experiments showed that melittin, RV-23, and AR-23 all had a typical α-helical structure, and RV-23 had the lowest α-helix content. The structural information showed that RV-23 has the lowest hydrophobicity and highest hydrophobic moment. Because hydrophobicity and α-helix content are believed to correlate with hemolysis, the results indicate that the selective lytic activity against bacteria of RV-23 may be due to its low hydrophobicity and α-helicity, which lead to low cytotoxicity without affecting antibacterial activity. Furthermore, RV-23 did not affect the structure and function of blood components such as red blood cells, platelets, albumin, and the blood coagulation system. In conclusion, RV-23 is a cell-selective antibacterial peptide with high hemocompatibility due to its unique structure.

• Applied Biological Chemistry
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• v.43 no.3
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• pp.174-178
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• 2000

To search CDK4/Cyclin D1 enzyme inhibition materials, methanol extracts of native eighty seven plant species in thirty seven families were screened in vitro for their inhibiting activities against CDK4/Cyclin D1 enzyme which are control to the normal cell division cycle in human body. Extracts of Paeonia suffruticosa, Saurus chinensis, Sanguisorba officinalis and Celastrus orbiculatus among them significantly inhibited above fifty percent $(in\;5\;{\mu}g/ml)$ against CDK4/ Cyclin D1 enzyme. Especially, the extracts of P. suffruticosa and S. officinalis showed moderately strong inhibition. Also, cryptotanshinone was identified as active compound from a extracts of Salvia mitiorrhiza by spectroscopic analyses including 2D NMR experiments.

• Parasites, Hosts and Diseases
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• v.57 no.5
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• pp.543-547
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• 2019

Toxoplasma gondii can infect humans worldwide, causing serious diseases in pregnant women and immunocompromised individuals. T. gondii rhoptry protein 13 (ROP13) is known as one of the key proteins involved in host cell invasion. In this study, we generated virus-like particles (VLPs) vaccine expressing T. gondii rhoptry ROP13 and investigated VLPs vaccine efficacy in mice. Mice immunized with ROP13 VLPs vaccine elicited significantly higher levels of T. gondii-specific IgG, IgG1, IgG2a, and IgA antibody responses following boost immunization and challenge infection, whereas antibody inductions were insignificant upon prime immunization. Differing immunization routes resulted in differing antibody induction, as intranasal immunization (IN) induced greater antibody responses than intramuscular immunization (IM) after boost and challenge infection. IN immunization induced significantly higher levels of IgG and IgA antibody responses from feces, antibody-secreting cells (ASCs), $CD4^+$ T, $CD8^+$ T cells and germinal center B cell responses in the spleen compared to IM immunization. Compared to IM immunization, IN immunization resulted in significantly reduced cyst counts in the brain as well as lesser body weight loss, which contributed to better protection. All of the mice immunized through either route survived, whereas all na?ve control mice perished. These results indicate that the ROP13 VLPs vaccine could be a potential vaccine candidate against T. gondii infection.

• Current Optics and Photonics
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• v.2 no.5
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• pp.448-452
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• 2018

A three-wavelength $Pr^{3+}:YLF$ laser at 604 nm, 607 nm and 640 nm simultaneously output by Fabry-Perot (F-P) etalon has been obtained. A 444 nm blue laser diode is used for pumping the $Pr^{3+}:YLF$ crystal, and a 0.1 mm F-P etalon is inserted in the resonator to select wavelength. The theoretical model of three-wavelength $Pr^{3+}:YLF$ laser is established, by adjusting the tilt angle of the etalon, the transmittances of the different wavelengths can be controlled, and the threshold values can be made to equalize by controlling the loss among different wavelengths. In the experiment, when the tilt angle of etalon is $9^{\circ}$ and the optimized length of resonator is 48 mm, the total output power of 25 mW at the three-wavelength is achieved at incident pump power of 7.5 W.

• Journal of Power Electronics
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• v.19 no.5
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• pp.1108-1121
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• 2019

The non-inverting buck-boost converter (NIBB) is a step-up and step-down DC-DC converter suitable for wide-input-voltage-range applications. However, when the input voltage is close to the output voltage, the NIBB needs to operate in the buck-boost mode, causing a significant efficiency reduction since all four switches operates in the PWM mode. Considering both the current stress limitation and the efficiency optimization, a novel design methodology for the optimal phase-shift modulation of a NIBB in the buck-boost mode is proposed in this paper. Since the four switches in the NIBB form two bridges, the shifted phase between the two bridges can serve as an extra degree of freedom for performance optimization. With general phase-shift modulation, the analytic current expressions for every duty ratio, shifted phase and input voltage are derived. Then with the two key factors in the NIBB, the converter efficiency and the switch current stress, taken into account, an objective function with constraints is derived. By optimizing the derived objective function over the full input voltage range, an offline design methodology for the optimal modulation scheme is proposed for efficiency optimization on the premise of current stress limitation. Finally, the designed optimal modulation scheme is implemented on a DSPs and the design methodology is verified with experimental results on a 300V-1.5kW NIBB prototype.

• Geomechanics and Engineering
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• v.29 no.2
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• pp.145-154
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• 2022

Complex geological conditions have a great influence on the mining of coalbed methane (CBM), which affects the extraction efficiency of CBM. This investigation analyzed the complicated geological conditions in the Liujia CBM block of Fuxin. A geological model of heterogeneities CBM reservoirs was established to study the influence of strike direction of igneous rocks and fault structures on horizontal well layout. Subsequently, the dual-porosity and dual-permeability mathematical model was established, which considers the dynamic changes of porosity and permeability caused by gas adsorption, desorption, pressure change. The results show that the production curve is in good agreement with the actual by considering gas seepage in matrix pores in the model. Complicated geological structures affect the pressure expansion of horizontal wells, especially, the closer to the fault structure, the more significant the effect, the slower the pressure drop, and the smaller the desorption area. When the wellbore extends to the fault, the pressure expansion is blocked by the fault and the productivity is reduced. In the study area, the optimal distance to the fault is 70 m. When the horizontal wellbore is perpendicular to the direction of coal seam igneous rock, the productivity is higher than that of parallel igneous rock, and the horizontal well bore should be perpendicular to the cleat direction. However, the well length is limited due to the dense distribution of igneous rocks in the Liujia CBM block. Therefore, the horizontal well pumping in the study area should be arranged along the direction of igneous rock and parallel plane cleats. It is found that the larger the area surrounded by igneous rock, the more favorable the productivity. In summary, the reasonable layout of horizontal wells should make full use of the advantages of igneous rock, faults and other complex geological conditions to achieve the goal of high and stable production.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.70-70
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• 2023

유자의 번식방법은 세 가지로 알려져 있다. 유자 대목의 유자를 접목하는 방법과 탱자 대목의 유자를 접목하는 방법, 유자의 종자를 파종하여 유자나무를 번식하는 방법 등이 있다. 이러한 번식 방법 가운데 가장 많이 활용되고 있는 유자의 번식 방법은 탱자 나무 대목에 유자를 접목하여 생산하는 방법이다. 실제로 유자의 생산물을 비교해보면 과일의 크기는 유자나무에 유자를 접목시킨 유자나무에서 대체적으로 과일이 크고 색깔도 진노랑색이다. 과일이 제일 작은 번식 방법은 유자 종자를 파종하여 유자를 생산하는 방법이다. 또한, 유자 접목 방법에 따른 유자의 생산 연령은 실생번식보다 접목방법이 훨씬 빠르다. 즉, 과일의 형태와 색깔, 향 등이 번식 방법에 따라서 다소 차이를 나타내고 있다. 따라서, 이러한 번식 방법에 따른 유자의 과육으로부터 항균 활성에 차이를 분석하고자 본 실험을 실시하였다. 3종의 항균실험을 실시한 결과 대부분의 균 종류의 결과를 보면 실생 번식에서 다소 양호한 항균활성을 나타내었다. 유자 대목의 유자를 접목한 유자의 과육도 비교적 항균활성이 좋게 나타났다. 탱자 대목에 유자를 접목하여 얻어진 유자 과육의 항균 활성은 다른 번식 방법에 비하여 다소 미흡한 항균 활성 결과를 나타내었다. 따라서, 이러한 결과들로 미루어볼 때 번식 방법에 따른 유자 과육의 항균 활성은 균 종류별 차이가 나는 것으로 판단되었다. 따라서, 이러한 결과들로 미루어 볼 때 향후 과피의 항균 활성을 조사한다면 더 좋은 결과를 확보할 수 있을 것으로 생각된다