• Journal of Microbiology and Biotechnology
• /
• 제23권9호
• /
• pp.1287-1292
• /
• 2013

Extracellular biogenic synthesis of silver nanoparticles with various shapes using the rice bacterial blight bacterium Xanthomonas oryzae pv. oryzae BXO8 is reported. The synthesized silver nanoparticles were characterized by UV-Vis spectroscopy, powder X-ray diffractometry (XRD), scanning electron microscopy, energy dispersive X-ray spectrometry, and high-resolution transmission electron microscopy (HR-TEM). Based on the evidence of HR-TEM, the synthesized particles were found to be spherical, with anisotropic structures such as triangles and rods, with an average size of 14.86 nm. The crystalline nature of silver nanoparticles was evident from the bright circular spots in the SAED pattern, clear lattice fringes in the high-resolution TEM images, and peaks in the XRD pattern. The FTIR spectrum showed that biomolecules containing amide and carboxylate groups are involved in the reduction and stabilization of the silver nanoparticles. Using such a biological method for the synthesis of silver nanoparticles is a simple, viable, cost-effective, and environmentally friendly process, which can be used in antimicrobial therapy.

• 한국자기학회지
• /
• 제13권6호
• /
• pp.226-230
• /
• 2003

제주도 지역의 특정위치를 선정하여 그 위치에서 채취한 화산암과 송이시료를 대상으로 상온에서 X-선형광법을 이용하여 시료의 화학조성을, X-선회절법과 Mossbauer분광법을 이용하여 시료에 함유된 광물, 산화철의 종류, 원자가상태와 자기적 성질을 분석하였다. 화산암과 송이시료는 SiO$_2$와 같은 규산염 광물이 주성분을 이루고 있고, olivine, pyroxene, ilmenite, hematite와 magnetite 등의 광물도 포함되어 있음을 확인하였다. 또한 화산암에 존재하는 철의 원자가 상태의 대부분은 Fe$^{2+}$이었고, 송이는 Fe$^{3+}$ 임을 알 수 있었다.

• Bulletin of the Korean Chemical Society
• /
• 제21권1호
• /
• pp.56-60
• /
• 2000

The mechanism of a matrix modification for the trace determination of volatile lead and bismuth by an electro-thermal atomic absorption spectrophotometry was studied by a X-ray diffractometry (XRD). For the investigation of structures, the ash products of the elements were produced by using a palladium as a matrix modifier with or without aluminum or nickel as an auxiliary modifier. The same charring conditions as in the analysis of samples were applied together with much concentrated solution of analytical elements and modifiers in a graphite furnace to get a large amount of the product for XRD. The XRD patterns showed PbPd3 for lead and BiPd3 for bismuth. These mean that the reaction procedures through the charring and atomization were changed from $Pb^{2+}$ ${\rightarrow}$ PbO ${\rightarrow}$$Pb^0$ to $Pb^{2+}$ ${\rightarrow}$ PbO ${\rightarrow}PbPd_3$ ${\rightarrow}$ Pb o for lead and from $Bi^{3+}$ ${\rightarrow}$ BiO ${\rightarrow}$ Bi o to $Bi^{3+}$ ${\rightarrow}$ BiO ${\rightarrow}$ $BiPd_3$ ${\rightarrow}$ $Bi^0$ for bismuth by the addition of modifiers. The volatile elements were stabilized by the formation of palladium alloys through a charring process. Charring temperatures were raised about 500 $^{\circ}C$ by the alloying and the atomization was also stabilized for the enhancement of sensitivities.

• 분석과학
• /
• 제22권4호
• /
• pp.285-292
• /
• 2009

장기 저장된 탄약은 화공품의 노화에 따른 절심현상(연소 중단)으로 인해 불발 등의 악작용이 발생하게 된다. 탄약에 주로 사용되는 화공품은 초기 에너지를 부여하는 뇌관 화약과 뇌관 화약의 에너지를 받아 지연제를 점화시켜주는 점화제, 일정 시간 동안 연소를 지연시켜주는 지연제 등을 사용한다. 이러한 형태의 탄약에는 뇌관화약, 점화제, 지연제의 순으로 충전되는데 충전된 순서대로 에너지가 전달되어 기능을 발휘하게 된다. 탄약의 절심 현상은 점화제의 연소중단, 점화제로부터 지연제로의 불충분한 에너지 전달, 지연제의 연소 중단 등에 의해 발생하는데, 이러한 현상이 나타나는 요인으로는 각 구성 성분의 낮은 순도,부적절한 혼합비, 입자성 성분의 입자 크기 및 분포, 바인더의 종류, 각 구성 성분의 혼합방법, 장기저장시 흡입된 수분에 의한 구성성분의 가수분해 및 고온에 의한 구성 성분의 화학적 변화 등이 의심된다. 본 연구의 목적은 Zr-Ni계 지연관 결합체를 장기 보관했을 때 점화제 및 지연제에서 나타나는 연소중단현상의 원인을 규명하는 것이다. 이를 위해 본 연구에서는 현장에서 일어나는 절심현상과 일치하는 시험법을 개발하였고, 장-흐름 분획법(field-flow fractionation, FFF)을 이용하여 입자성 성분의 입자 크기와 분포를 조사하였으며, 장기보관에 의한 점화제와 지연제의 화학적인 변화 메커니즘을 조사하기 위하여 열분석(differential scanning calorimetry) 및 XRD, XPS (X-ray diffractometry, X-ray photoelectron Spectroscopy)분석을 수행하였다. XPS 와 XRD data 에 의하면, 점화제의 경우 산소의 1s 결합에너지 위치에서 M-O,M-OH 피크들이 관찰되었다. 이는 산화에 의한 새로운 생성물이 생성되었음을 의미한다. 즉 점화제의 산화에 의해 방출 열량이 감소하여 절심(연소 중단) 현상이 야기된다는 사실을 확인할 수 있었다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1996년도 추계학술대회 논문집
• /
• pp.175-179
• /
• 1996

Ferroelectric SrBi$_2$Ta$_2$$O_{9}$ thin films were fabricated by tole Sol-Gel method using a spin-on coating with MOD(Metal Organic Dccomposition) solution on Pt/Ti/SiO$_2$/Si(100) substratcs. The films were anncalcd at 80$0^{\circ}C$ for one hour in oxygen atmosphere. The effects of Bi/Ti mole ratios on crystalline orientations, surface morphologies, and subface composition SBT thin films with a Bi/Ta mole ratios from 1.1 to 1.3 were investigated using X-ray Diffractometry (XRD). Atomic Force (AFM), X-Ray Photoelectron Spectroscopy(XPS). Ferroelectric properties of these films were also measured.d.

• 한국세라믹학회지
• /
• 제44권11호
• /
• pp.650-654
• /
• 2007

[ $SnO_2$ ]-doped $TiO_2$ thin films were prepared from tin (IV) bis (acetylacetonate) dichloride and titanium diisopropoxide bis (acetylacetonate) with pluronic P123 or degussa P25 as a structural-directing agent. These hydrolyzed sol were spin coated onto Si(100) wafer substrate. The microstructure, morphology and bonding states of thin films were studied by field-emission scanning electron microscopy (FE-SEM), X-ray diffractometry (XRD), and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of these films was investigated by using indigo carmine solution.

• 한국재료학회지
• /
• 제18권3호
• /
• pp.143-147
• /
• 2008

Fe compounds in scoria as distributed in the south-western area of Jeju Island were investigated using X-ray fluorescence spectroscopy, X-ray diffractometry, and $^{57}Fe$ $M{\ddot{o}}ssbauer$ spectroscopy. The samples were prepared from four parasite volcanoes. It was found that these samples are typical basalt comprised of $SiO_2$, $Al_2O_3$, Fe, and silicate minerals. The $M{\ddot{o}}ssbauer$ spectra showed doublets for olivine, pyroxene, and ilmenite as well as sextets for hematite and magnetite. The valence state of Fe is chiefly a 3+ charge state with a slight 2+ charge state. It is expected that these results will add to the body of information related to the formation mechanisms of Jeju Island.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2008년도 추계학술대회 초록집
• /
• pp.47-47
• /
• 2008

Cr and AlSi (Si=20 and 66 at.%) target들을 이용하여 Closed-field unbalanced magnetron sputtering (CFUBMS)으로 증착된 주기($\Lambda$)가 2.3 nm에서 8.0nm인 CrN/AlSiN multilayer coatings의 crystal structure, 화학적 조성, 및 기계적 특성을 glow discharge optical emission spectroscopy (GDOES), X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS) and nano-indenter 등의 분석장비를 이용하여 분석하였다. 고온안정성을 시험하기 위하여 $800^{\circ}C$와 $1000^{\circ}C$ 공기중 에서 30분 열처리하였다. CrN/AlSiN multilayer coatings의 고온안정성은 Si조성이 증가함에 따라 향상되었다. Si이 18.2 at.%함유된 coating이 가장 우수한 고온안정성을 갖고 있다.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2012년도 춘계학술발표회 논문집
• /
• pp.295-295
• /
• 2012

The $TiO_2$ films were prepared in the $H_2SO_4$ solution containing $NH_4F$ at different anodic voltages, to compare the photocatalytic performances of titania for purification of waste water. The microstructure was characterized by a Field-emission scanning electron microscopy (FE-SEM) and X-ray diffractometry (XRD). Chemical bonding states and co-doped elements of F and N were analyzed using surface X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of the co-doped $TiO_2$ films was analyzed by the degradation of aniline blue solution. From the result of diffuse reflectance absorption spectroscopy(DRS), it is indicated that the absorption edge of the F-N-codoped $TiO_2$ films shifted toward visible light area, and the photocatalytic reaction of $TiO_2$ was improved by doping an appropriate contents of F and N.

• Mass Spectrometry Letters
• /
• 제14권3호
• /
• pp.110-115
• /
• 2023

The reaction of (COD)PdCl₂ with new C₃-symmetric tridentate L (COD = 1,5-cyclooctadien; L = 1,3,5-tris(picolinoyloxyethyl)cyanurate) in a mixture of acetone and dichloromethane produces single crystals consisting of unprecedented monometallacyclic [PdCl₂(L)]. This cyclic compound arises from trans-chelation of two of three donating pyridyl groups of L, while the third pyridyl group remains uncoordinated. Electrospray ionization mass spectrometry (ESI-MS) data on L exhibited the major peak corresponding to [C₂₇H₂₄N₆O₉ + H⁺]⁺. Fast atom bombardment mass spectrometry (FABMS) data on [PdCl₂(L)], however, showed the mass peak corresponding to the L instead of the present palladium(II) compound species, due to the insolubility and dissociation in solution. The physicochemical properties of the present palladium(II) compound were fully characterized by means of infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy, thermal analysis, single-crystal X-ray diffraction (SC-XRD) measurement.