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Raman Structural Study Of Olefin Blends
Full text linkWe carried out detailed Raman structural study ofmelt-mixed blends of linear low-densitypolyethylene (PE) and isotactic polypropylene (PP).The relative content of PE in the PE/PP blendsvaried from 13 to 75 %. We show that Ramanspectroscopy can be effectively used for aquantitative analysis of phase and conformationalcompositions of these blends. The changes in thesecompositions due to changing the content of theblend components are discussed. Also, we studied astructure of the amorphous phase of reactor blendsof PE with random ethylene/1-hexene copolymer(CEH)
Laser-induced chemical liquid-phase deposition of copper on transparent substrates
Full text linkLaser-induced chemical liquid phase deposition allows maskless manufacturing of metallic structures on the surface of dielectrics and is prospected to be a promising tool in the field of microelectronics and microfluidics. The aim of the work presented here is to combine this deposition method with a related micro-structuring method known as laser-induced backside wet etching. Fabricating both, microstructured surface structures and subsequent deposition of conducting patterns within the same setup would be an interesting tool for rapid prototyping.To demonstrate the functional principle of this combined approach conductive copper lines were deposited at the backside of both polished and structured soda lime glass substrates by using a focused, scanning ns-pulsed Ytterbium fiber laser at 532nm wavelength. The deposition process is initiated by a photo induced reaction of a CuSO4-based liquid precursor in contact with the backside of the substrate. The obtained metallic copper deposits are crystalline, stable under ambient conditions and have a conductivity in the same order of magnitude as bulk copper
Nanostructure Formation on Solid Surfaces melted by Laser Pulse
Full text linkThe paper describes the model of nanostructureformation on solid surface by nanosecond laserpulses melting the material. Stefan problem withcorresponding boundary conditions is solved incombination with nucleation theory. It is found thattypical size of surface nanostructure formeddepends on energy and duration of laser pulse. Forcomparison of theoretic and experimental resultsvarious industry material (germanium, titanium,zirconia dioxide) pieces irradiated by ArF-laser areshown
Photon-Correlation Spectroscopy in Albumin Water Solutions Containing Gadolinium Ions
Full text linkGadoteric acid and gadodiamide molecules havegadolinium-containing chelate structures that areused in magnetic resonance tomography (MRT). [1].Over the past two decades, they were considered safeand effective for medical imaging. However, recentresults indicate the presence of gadolinium in the skinand soft tissues in patients with renal insufficiency,even with the current hemodialysis [2]. Nephrogenicsystemic fibrosis (NSF), which was described in1997, is a recently discovered rare disease ofunknown etiology that affects patients with renalinsufficiency. The development of NSF was directlylinked to the influence of gadolinium-containingmagnetic resonance contrast agents in 2006 [3]
Self-Q-switched Cr,Nd:ReVO4 (Re=Gd, Y) crystal lasers
Full text linkSelf-Q-switched Cr,Nd:ReVO4 (Re=Gd, Y) crystallasers are demonstrated. The spectroscopic and self-Q-switched laser properties of Cr,Nd:ReVO4 arestudied. Polarized absorption spectra weremeasured at room temperature, which showed thatthe absorption bands display polarization characterand an absorption band of Cr5+ ions at 1110 nmenables the crystals to be self-Q-switched lasermaterials. The maximum pulse energy are achievedto be 1.12 μJ with Re=Gd , and the shortest pulsewidth is 85.8 ns with Re=Y. The results show thatCr,Nd:ReVO4 crystals are new potential self-Qswitchedlaser materials
Supercontinuum Generation over 2 µm
Full text linkEffective supercontinuum generation in fiber mediain spectral range over 2 μm was experimentallydemonstrated. Supercontinuum generation wasobserved in passive optical fibers. Maximumspectral broadening was obtained in germaniumdopedfibers with longest wavelength near 2.7 μm.To provide high spectral density we used opticalfiber amplifiers. Thus supercontinuum generationwas obtained in holmium optical fiber amplifiersmedium with spectral density 10 W/nm, in therange from 2 to 2.5 μm. In thulium fiber amplifiersobserved amplification not only in conventionalrange near 1.8 μm, but in spectral range from 2.3 to2.5 μm, that corresponds to 3H4→ 3H5 opticaltransition possibility in thulium-doped opticalfibers
Fluorescent properties of the kindling fluorescent protein (KFP) at acidic pH values
Full text linkKindling fluorescent protein (KFP) is the photoswitchable protein which can be used in high-resolution microscopy and as a quencher in FRET-sensors. Fluorescent properties of KFP depend on pH value. In this paper we investigate the influence of pH on the spectral properties and kindling/quenching ability of KFP in the acidic pH region.Shift to the acidic region leads to the increase of fluorescence intensity of KFP over time. The excitation spectrum has a new peak near 455nm, giving two peaks - 530 and 590nm – in emission spectrum. We can assume that this maximum corresponds to the appearance of protonated form of the KFP chromophore.Analysis of fluorescence decay curves of KFP in H2O and D2O showed the presence of the kinetic isotope effect, which can be caused by the proton transfer from solvent molecules to the KFP chromophore, confirming the hypothesis that in the acidic pH region protonated form of KFP chromophore appears.At acidic pH irradiation of KFP with green light doesn’t lead to fluorescence increase, while blue light doesn’t quench the fluorescence. It means that KFP is also in the bright form, and there is no conformational states of protein which can be quenched by blue light
Measuring Optical Properties On Rough And Liquid Metal Surfaces
Full text linkFor understanding and optimizing laser processing of metals and alloys the optical properties, especially the absorption of the work piece in function of the temperature up to the liquid phase have to be known [1]. There are several approaches to extend the Drude-Model [2] for optical properties of metal to temperature dependence [3, 4, 5]. However, a verification of these models is difficult due to the lack of sufficient experimental data. Even though measuring optical properties with ellipsometry is well established, such measurements on metals and alloys at elevated temperatures up to the liquid state are very challenging. To collect the optical properties of different metals and alloys like Al, Ti, Ag, Cu and steel in the solid and liquid state a custom-made high-temperature ellipsometer was used. The instrument is also used to investigate the influence of curved and rough surfaces which may occur due to the heating of the samples during the ellipsometric measurements
THz and Raman Spectroscopy in Steroid Chemistry
Full text linkThe terahertz time-domain and Raman spectra of steroids in the region of 0.1-3.5 THz have been measured. Steroids have several intense and specific absorption features in the THz frequency region. The features are uniquely determined by a hormone structure. This allows us to analyze steroids in complex samples such as pharmaceuticals, foodstuffs and biological fluids, and in process of the pharmacological and chemical synthesis
PPLN Crystals for Nonlinear-optical Detection of Terahertz Wave Radiation
Full text linkPeriodically poled lithium niobate crystals can be utilized in nonlinear-optical spectral brightness detectors of terahertz range. In this paper characteristics of detectors were determined by analyzing spectra of spontaneous parametric down- and up-conversion in these crystals
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