• 한방안이비인후피부과학회지
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• 제17권1호
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• pp.154-162
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• 2004

The flowers of Lonicera japonica Thunb. (Caprifoliaceae) have been used as a traditional effective drug in treating bacillary dysentery, purulence. However, the exact role of Lonicera japonica in allergic reaction has not been clarified yet. Immediate hypersensitivity, popularly known as allergy, is a major clinical problem in humans. It has been found that the histamine release from mast cells is an essential step in the pathological process of immediate hypersensitivity. In this study, the effect of aqueous extract of Lonicera japonica (AELJ) on allergic reaction was investigated. AELJ inhibited the compound 48／80-induced anaphylactic reactions and antigen-induced passive cutaneous anaphylaxis (PCA). AELJ in vitro exhibited a dose-dependent inhibition of degranulation in RPMC stimulated by compound 48／80. AELJ also suppressed the morphological changes and the increase of intracellular free calcium level induced by compound 48／80. These results suggest that inhibitory effect of AELJ on allergic reaction may be mediated through the decrease of intracellular free calcium levels, and AELJ importantly contributes to the treatment of anaphylaxis and may be useful for other allergic disease.

• 한국주조공학회지
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• 제25권5호
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• pp.203-208
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• 2005

The main emphasis of this study is to optimize the process variables for manufacturing aluminum foam materials by direct foaming of remelted aluminum scraps. Aluminum foams were fabricated from two different raw materials, pure aluminum and used beverage cans. For both cases, $TiH_{2}$ was used as a foaming agent. Calcium was added as a thickener for the foaming of pure aluminum and no thickener was added for that of used beverage Cans because the pre-existing oxides of the used beverage cans are used as a thickener. Calcium and $TiH_{2}$ content varies from 0.5wt.% to 2.0wt.% and from 0.5wt.% to 1.5wt.%, respectively. The processing conditions, such as the effect of calcium on the melt viscosity, foaming temperature, and the optimum amount of the foaming agent with regard to the melt viscosity were discussed.

• Transactions on Electrical and Electronic Materials
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• 제16권3호
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• pp.135-138
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• 2015

A manganese dioxide (MnO₂) layer and zinc (Zn) layer are used as the cathode and the anode to develop filmtype manganese battery, in which a stack of a MnO₂ layer, gel electrolyte, and Zn layer are sandwiched between two plastic layers. This paper describes the chemical equation of swelling control upon the film-type manganese battery. We examined the reduction of hydrogen formation, by using calcium hydroxide Ca(OH)₂ as an additive in the electrolyte of film-type manganese battery. The phenomena or an effect of reduced hydrogen gas was proven by cyclic voltammogram, X-ray photoelectron spectra (XPS), and volume of hydrogen formation. The amount of H₂ gas generation in the presence of Ca²⁺ ion was reduced from 4.81 to 4.15 cc/g-zinc (14%), and the corrosion of zinc electrode in the electrolyte was strongly inhibited as time passed.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.475-476
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• 2006

Using microwave synthesized HAp nano powder and polymethyl methacrylate (PMMA) as a pore-forming agent, the porous biphasic calcium phosphate (BCP) ceramics were fabricated depending on the sintering temperature. The synthesized HAp powders was about 70-90 nm in diameter. In the porous sintered bodies, the pores having $150-180\;{\mu}m$ were homogeneously dispersed in the BCP matrix. Some amounts of pores interconnected due the necking of PMMA powders which will increase the osteoconductivity and ingrowth of bone-tissues while using as a bone substrate. As the sintering temperature increased, the relative density increased and showed the maximum value of 79.6%. From the SBF experiment, the maximum resorption of $Ca^{2+}$ ion was observed in the sample sintered at $1000^{\circ}C$.

• Restorative Dentistry and Endodontics
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• 제46권4호
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• pp.58.1-58.8
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• 2021

Objectives: This study addresses the effect of using nanoparticles (np) on the antimicrobial properties of bioactive glass (BAG) when used in intracanal medicaments against Enterococcus faecalis (E. faecalis) biofilms. Materials and Methods: E. faecalis biofilms, grown inside 90 root canals for 21 days, were randomly divided into 4 groups according to the antimicrobial regimen followed (n = 20; BAG-np, BAG, calcium hydroxide [CaOH], and saline). After 1 week, residual live bacteria were quantified in terms of colony-forming units (CFU), while dead bacteria were assessed with a confocal laser scanning microscope. Results: Although there was a statistically significant decrease in the mean CFU value among all groups, the nano-group performed the best. The highest percentage of dead bacteria was detected in the BAG-np group, with a significant difference from the BAG group. Conclusions: The reduction of particle size and use of a nano-form of BAG improved the antimicrobial properties of the intracanal treatment of E. faecalis biofilms

• 한국주조공학회지
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• 제26권6호
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• pp.267-271
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• 2006

Metal foam is a class of attractive materials, which exhibits unique combinations of physical, mechanical, thermal, electrical and acoustic properties. In particular, it is light and good at absorbing energy, which makes it attractive in automotive and aerospace applications weight is critical. In this paper, the Mg alloy foam was prepared by melt foaming method by addition of calcium as thickening agent, and $TiH_2$ or $CaCO_3$ powder as blowing agent. The macrostructural observation of foamed Mg showed that the pore structures of Mg alloy foam made by $CaCO_3$ as blowing agent were much better than that of foams made by $TiH_2$ as blowing agent. In addition, this paper showed the possible reason of fabrication magnesium alloy foam in proportion to blowing agent and the porosity range was about 40 to 76% as results value.

• 한국결정성장학회지
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• 제27권1호
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• pp.47-56
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• 2017

본 연구에서는 Alumina 골재를 사용한 fly ash-blast furnace slag계 Geopolymer의 내열성 건축자재로서의 사용 가능성을 검토하기 위하여 고온조건에서의 열적 특성에 대하여 조사하였다. 모든 배합조건에서 Geopolymer 경화체의 표면 크랙은 $800^{\circ}C$까지는 관찰되지 않았으며, 이것은 열처리 전후 강도의 변화가 작은 것과 일치한다. 또한, $800^{\circ}C$까지 고로슬래그의 혼합비율이 60 wt%일 때 잔존압축강도가 가장 우수한 것으로 나타났다. Geopolymer 경화체의 주요 수화 생성물은 $20{\sim}35^{\circ}$(2theta) 범위의 비정질 halo 패턴과 원재료의 mullite($3Al_2O_3{\cdot}2SiO_2$)와 quartz($SiO_2$)가 확인되었다. 비정질 halo 패턴은 Geopolymer 축중합 반응에 의해서 생성된 aluminosilicate gel이며, $800^{\circ}C$까지는 aluminosilicate gel의 halo 패턴이 유지되고 있음을 알 수 있다. $1,000^{\circ}C$에서 aluminosilicate gel의 패턴은 사라지며 열처리온도의 증가와 함께 gehlenite, calcium silicate, calcium aluminum oxide, microcline와 같은 결정상이 관찰되었다.

• 자원리싸이클링
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• 제26권1호
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• pp.37-42
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• 2017

이산화탄소 저감을 위한 유효한 방법 중의 하나로 칼슘규산염 광물의 간접탄산염화 공정이 보고되고 있다. 이 공정은 염산, 질산 등의 산에 의하여 칼슘규산염으로부터 칼슘성분을 침출하는 단계와 이산화탄소에 의한 침출용액의 탄산염화 단계의 두 과정으로 구성된다. 침출용매로 초산수용액을 사용하는 경우에는 침출용액을 이산화탄소로 탄산염화 하는 과정에서 초산이 재생성 되어 침출단계로 순환되어 침출용매로 재사용될 수 있다. 제철 및 제강슬래그와 같은 산업부산물은 칼슘규산염을 많이 함유하고 있어 간접탄산염화공정의 원료로 사용될 수 있다. 본 연구에서는 초산수용액에 의한 국내 전기로제강슬래그의 침출효율을 조사하기 위하여, 초산수용액 농도, 침출온도 및 침출시간 등의 침출조건 변화에 따른 침출실험을 수행하였다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.152-152
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• 2017

Titanium and its alloys have been widely used for biomedical applications. However, the use of the Ti-6Al-4V alloy in biomaterial is then a subject of controversy because aluminum ions and vanadium oxide have potential detrimental influence on the human body due to vanadium and aluminum. Hence, recent works showed that the synthesis of new Ti-based alloys for implant application involves more biocompatible metallic alloying element,such as, Nb, Hf, Zr and Mo. In particular, Nb and Hf are one of the most effective Ti ${\beta}$-stabilizer and reducing the elastic modulus. Plasma electrolyte oxidation (PEO) is known as excellent method in the biocompatibility of biomaterial due to quickly coating time and controlled coating condition. The anodized oxide layer and diameter modulation of Ti alloys can be obtained function of improvement of cell adhesion. Silicon (Si) and magnesium (Mg) has a beneficial effect on bone. Si in particular has been found to be essential for normal bone and cartilage growth and development. In vitro studies have shown that Mg plays very important roles in essential for normal growth and metabolism of skeletal tissue in vertebrates and can be detected as minor constituents in teeth and bone. Therefore, in this study, Si and Mg coatings on the hydroxyapatite film formed Ti-29Nb-xHf alloys by plasma electrolyte oxidation has been investigated using several experimental techniques. Ti-29Nb-xHf (x= 0, 3, 7 and 15wt%, mass fraction) alloys were prepared Ti-29Nb-xHf alloys of containing Hf up from 0 wt% to 15 wt% were melted by using a vacuum furnace. Ti-29Nb-xHf alloys were homogenized for 2 hr at $1050^{\circ}C$. The electrolyte was Si and Mg ions containing calcium acetate monohydrate + calcium glycerophosphate at room temperature. The microstructure, phase and composition of Si and Mg coated oxide surface of Ti-29Nb-xHf alloys were examined by FE-SEM, EDS, and XRD.

• Bulletin of the Korean Chemical Society
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• 제33권6호
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• pp.1845-1850
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• 2012

Layered metal hydroxides (LMHs) containing calcium were synthesized by coprecipitation in solution having two different trivalent metal ions, iron and aluminum. Two mixed metal solutions ($Ca^{2+}/Al^{3+}$ and $Ca^{2+}/Fe^{3+}$ = 2/1) were added to sodium hydroxide solution and the final pH was adjusted to ~11.5 and ~13 for CaAl-and CaFe-LMHs. Powder X-ray diffraction (XRD) for the two LMH samples showed well developed ($00l$) diffractions indicating 2-dimensional crystal structure of the synthesized LMHs. Rietveld refinement of the X-ray diffraction pattern, the local structure analysis through X-ray absorption spectroscopy, and thermal analysis also confirmed that the synthesized precipitates show typical structure of LMHs. The chemical formulae, $Ca_{2.04}Al_1(OH)_6(NO_3){\cdot}5.25H_2O$ and $Ca_{2.01}Fe_1(OH)_6(NO_3){\cdot}4.75H_2O$ were determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Particle morphology and thermal behavior for the synthesized LMHs were examined by field emission scanning electron microscopy and thermogravimetricdifferential scanning calorimetry.