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1.
In this study, the thermal protective performance of nonwoven fabrics made of Nomex (polyisophthaloyl metaphenylene diamine), PPS (polyphenylene sulfide), P84 (polyimide), and basalt fibers was investigated. The objective was to determine the influence of fiber type, thickness of fabric, and wet on the thermal protective performance of nonwoven fabric. The thermal resistances of different nonwoven fabrics were measured using a dry hot plate instrument, the basalt nonwoven fabrics had a highest thermal resistance in all fabric, and the thermal resistance of nonwoven fabric increased with the increase in thickness. The six nonwoven fabrics were exposed to a hot environment for a few minutes by using a self-designed apparatus. The test results showed that the nonwoven fabrics made with basalt fiber exhibited the best thermal protective performance, and the thermal protective abilities of nonwoven fabrics increased with fabric thickness. Interestingly, nonwoven fabrics with added water were found to be able to keep the fabric surface lower temperature compared to dry fabrics when exposed to a hot environment, indicating the excellent thermal protective performance of wet nonwoven fabrics. 相似文献
2.
Jeya Rajendran T. Lekshmana Thanu Lingam M. Jose S. Jerome Das 《Journal of Thermal Analysis and Calorimetry》2011,103(3):845-851
A single crystal of heptaaqua-p-nitrophenolatostrontium(II) nitrophenol (HNSN) was grown, and the structure was confirmed by UV–Vis–NIR, FT-IR, FT-NMR, and
high-resolution X-ray diffraction (HRXRD) analyses. The dielectric loss, dielectric constant, and the mechanical strength
of the crystal have already been reported. The dynamic, non-isothermal thermal analysis was carried out at different heating
rates, and TG and DTG data were used for the interpretation of the mechanisms and kinetics of decomposition by means of a
model fitting method, Coats–Redfern equation, and a model-free method, Kissinger and Flynn–Wall method. The values of activation
energy (E) and the pre-exponential factor (ln A) of each stage of thermal decomposition at various linear heating rates were calculated. 相似文献
3.
Carina Gargori García Roberto Galindo Llorach Mario Llusar Vicent Maria Angeles Tena Gómez Guillermo Monrós Tomás Jose A. Badenes March 《Journal of Sol-Gel Science and Technology》2009,50(3):314-320
Glasses on SiO2–CaO–ZnO–B2O3–K2O–Al2O3 oxide system modified by addition of titania (0, 3, 5, 12, and 20% w) have been prepared by sol–gel method. The obtained
gels were aged, dried and fired at 600 °C/1 h in order to stabilise the glass. The resulting fired powders were characterised
by UV–Vis–NIR spectroscopy, scanning electron microscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD).
Their photocatalytic capacity on the degradation of Orange II dye has been studied. The XRD and TEM studies indicate that
system becomes amorphous with a nanostructured microstructure. From UV–Vis–NIR results the band gap calculated is around 3.5 eV
for all modified glasses. Photoactivity of powders depends on amount of titania in glass composition and the specific surface
area of prepared samples. The sample with highest surface area and lowest addition of titania (3% w sample) shows similar
activity than commercial anatase used as reference. 相似文献
4.
S. Janarthanan R. Sugaraj Samuel Y. C. Rajan S. Pandi 《Journal of Thermal Analysis and Calorimetry》2012,107(3):1213-1217
Semicarbazone of dl-camphor (SdlC) crystals were grown using methanol as a solvent by slow evaporation solution growth technique at room temperature. Formation
of the product and the presence of various functional groups present in the grown crystal have been identified using FTIR
spectra. Single crystal XRD study was conducted to obtain the crystal structure and lattice parameters. The grown crystal
was subjected to 1HNMR and 13CNMR spectral studies and TG-DTA in order to confirm its structure, purity, and stability, respectively. The optical transparency
of the crystal was tested using UV–Vis–NIR spectroscopy. The nonlinear optical (NLO) property of the grown crystal was confirmed
from the second harmonic generation (SHG) by Kurtz–Perry powder test. 相似文献
5.
Coir-fiber-based fire retardant nano filler has been developed for epoxy resin (ER). At first, the coir fiber was brominated
with saturated bromine water and then treated with stannous chloride solution. After drying, it was grinded to nano dimension
and mix well with ER for composites preparations. FTIR, DSC, and TG techniques were used to characterize the brominated coir
fiber. Gravimetric analysis shows only 10% by mass of bromination on coir fiber. Bromination decreases the thermal stability
of the coir fiber, but it does not affect the final stability of the composites. This study concentrates on the thermal, fire
retardant, and morphological properties of nanocomposites prepared by direct mixing. The fire retardancy properties (smoke
density and limiting oxygen index) of coir–epoxy nanocomposites have increased significantly. 相似文献
6.
A method for the decolourization of coloured cotton fabric dyed with vat dyes, based on exposure to infrared laser light,
has been tested. Pulsed CO2 laser has been used for all experiments. To detect changes in colour shade, reflection data of original and dyed cotton irradiated
at various fluency of infrared laser light were measured on a UV–VIS spectrophotometer, and then colour intensity was calculated
for each vat dye. To observe changes in chemical composition and morphology of fiber surfaces, an analysis was performed by
X-ray photoelectron spectroscopy and scanning electron microscopy due to thermal effects. Thermal stability of vat dyes and
cotton fabric was determined with differential scanning calorimetry method to simulate the heating process during exposure
of samples to the infrared laser irradiation. 相似文献
7.
Alexander A. Nekrasov Oxana L. Gribkova Victor F. Ivanov Anatoly V. Vannikov 《Journal of Solid State Electrochemistry》2010,14(11):1975-1984
With the purpose of determining prospects of possible applications of interpolymer complexes of polyaniline (PANI) with poly(amidosulfonic
acid)s, we have performed a comparative study of polyaniline films prepared by electrochemical polymerization of aniline in
the presence of the polyacids distinguished by different rigidities of the polymer backbone: (1) poly(2-acrylamido-2-methyl-1-propanosulfonic
acid) (flexible backbone); (2) poly-p,p′-(2,2′-disulfoacid)-diphenylen-iso-phthalamid (semi-rigid backbone); (3) poly-p,p′-(2,2′-disulfoacid)-diphelylen-tere-phthalamid (rigid backbone); and (4) a copolymer of the latter two acids with monomer
feed ratio 1:1 (co-PASA). Spectroelectrochemical studies in the UV–vis–NIR range showed that PANI complexes with rigid-chain
polyacids far more effectively modulate absorbance in the Vis–NIR range and can be considered as promising candidates for
“smart windows” development. Due to the presence of bulky unmovable polyacid anion, PANI interpolymer complexes (particularly
those with the semi-rigid-chain polyacids) possess much wider pH range of electroactivity than common PANI, which is of great
importance for biosensor applications. The interpolymer complexes with flexible-chain and semi-rigid-chain polyacids exhibit
good optical response to ammonia vapors at conditions of high humidity, which make them promising materials for the development
of ammonia optical sensors. 相似文献
8.
Jiangbo She Chao Gao Kai Cui Chaoqi Hou Wei Zhao Wei Wei Bo Peng 《Structural chemistry》2008,19(6):905-910
A novel neodymium pentafluoropropionate binuclear complex, Nd(C2F5COO)3 · Phen (Phen: 1,10-phenanthroline), was synthesized and characterized by single-crystal X-ray diffraction, elemental analysis,
FT-IR spectra, UV–Vis–NIR absorption, and PL spectra. Single-crystal data show that the complex bears centrosymmetric dinuclear
structure with a planar ligand configuration. Four carboxylato groups act as η2-chelate-μ2-carboxylato-k1O:k1O′-bridge-ligands, the other two occupy the terminal position as monodentate ligands. At the same time, the C–O distances
appear averaged which indicate the three atoms of carboxylato forming electron-conjugate system. Hydrogen bond and π–π-stacking
link the binuclear to two-dimensional sheet. Optical spectra exhibit the complex possesses typical Nd(III) ion absorption
and photoluminescence emission. 相似文献
9.
Phostungstic acid (PWA) nanoclusters grafted onto high surface area polycrystalline hydrous zirconia powder (PWA/ZrO2) was prepared by wet impregnation method. The zirconia particles were synthesized using a modified sol–gel route. The obtained
material was characterized by X-ray diffraction (XRD), UV–Vis–diffuse reflectance spectroscopy (UV–Vis–NIR–DRS), infrared
spectroscopy (FTIR), transmission electron microscopy (TEM) and sorptometric techniques. XRD study revealed the presence of
tetragonal phase of zirconia in the synthesized sample. TEM study indicates presence of small PWA clusters with size in the
range of 5–15 nm well dispersed on the surface of the ZrO2 particles. The characteristic UV and IR absorption feature of the PWA was retained in the PWA/ZrO2 material. The PWA/ZrO2 material was used as an efficient catalyst for the preparation of octahydroquinazolinones and β-acetamido ketones. The octahydroquinazolinones
were synthesized by the multicomponent condensation of dimedones, urea and aryl aldehydes in ethanol. Similarly, β-acetamido
ketones were synthesized with high yield and purity by four component condensation of aryl aldehydes, enolizable ketones,
and acetyl chlorides in acetonitrile. The protocols developed in this investigation using the PWA/ZrO2 catalyst is advantageous in terms of simple experimentation, high yield and purity of the products and recovery and reutilization
of the heterogeneous catalyst. 相似文献
10.
X. C. Lou X. J. Zhao Y. L. Xiong X. T. Sui 《Journal of Sol-Gel Science and Technology》2010,54(1):43-48
Al–B–NiO thin films were prepared using the sol–gel process and deposited on Indium tin oxide (ITO)-coated glass substrates
via the dip-coating technique for the purpose of developing high performance electrochromic materials. The influence of the
anneal on the structural and electrochromic properties of Al–B–NiO films is reported. Thermogravimetry (TG) and differential
thermal analysis (DTA), cyclic voltammetry measurements (CV), UV spectrophotometer, atomic force microscopy (AFM) and X-ray
diffraction (XRD) have been used to investigate the structural and electrochromic properties. The thickness of the films was
determined by spectrophotometric analysis in 350–1,000 nm wavelength. Results showed that the Al–B–NiO thin films treated
at high temperature have both the excellent electrochromic properties and good reversibility. The transmittance change (ΔT)
of the film treated at 500 °C reaches still ~50% at the wavelength of 550 nm. The microstructure and the surface morphology
were considered to play an important role in the electrochromic properties with different temperatures. 相似文献
11.
S. K. Arya Tanvi Vats Shailesh N. Sharma Kulvir Singh A. K. Narula 《Journal of Thermal Analysis and Calorimetry》2012,107(2):555-560
In this study, we have studied the stability of TiO2–CdSe nanocomposites in which the individual moieties are linked using a bifunctional linker (mercaptopropionic acid). Nanoparticles
of TiO2 and CdSe are synthesized by sol–gel and one pot methods. The equimolar amount of the above particles is utilized to prepare
nanocomposites with and without linker. These samples are characterized for their structural, thermal, and optical properties
using X-ray diffraction (XRD), differential thermal analysis (DTA), thermogravimetric analysis (TG), Fourier transform infra-red
spectroscopy (FTIR), and UV–Vis spectroscopy. The average particle size of TiO2 and CdSe are 16 and 23 nm, respectively. The addition of a bifunctional linker shows remarkable effect on the properties
of TiO2–CdSe nanocomposites. 相似文献
12.
P. S. Epaminondas K. L. G. V. Araújo J. A. Nascimento M. C. D. Silva R. Rosenhaim L. E. B. Soledade N. Queiroz A. L. Souza I. M. G. Santos A. G. Souza 《Journal of Thermal Analysis and Calorimetry》2011,106(2):545-550
Physico-chemical properties, spectroscopy, and thermal analyses were used aiming at evaluating the influence of toasting and
of the flaxseed variety on thermo-oxidative behavior of flaxseed oils. Thermogravimetry (TG) and differential scanning calorimetry
(DSC) were associated to gas chromatography, infrared spectroscopy and UV–Vis spectroscopy, as well as to physico-chemical
analyses to characterize the oils obtained from raw and toasted flaxseeds. No meaningful differences in the thermal and oxidative
stabilities were noticed comparing oils obtained from the brown and the golden flaxseeds. Nevertheless, the UV–Vis spectra
indicated that both flaxseed oils were at the beginning of the oxidation process. The previous toasting of the seeds led to
a higher oxidation for both varieties being harmful to the flaxseed oil quality. 相似文献
13.
Lucica Viorica Ababei Angela Kriza Cristian Andronescu Adina Magdalena Musuc 《Journal of Thermal Analysis and Calorimetry》2012,107(2):573-584
Ten new mononuclear complexes having general formulae [ML2](ClO4)2, M = Cu(II), Co(II), Ni(II), Mn(II) and Zn(II), [ML2](SO4), M = Co(II), Ni(II) and [ML2(H2O)2](SO4), M = Cu(II), Mn(II) and Zn(II), L = 2-acetyl-pyridyl-isonicotinoylhydrazone have been synthesized and characterized based
on elemental analyses, IR spectroscopy, UV–Vis–NIR, EPR, as well as thermal analysis and determination of molar conductivity
and magnetic moments. The structures of [CoL2](ClO4)2 are accomplished by single crystal X-ray diffraction. The coordination sphere is formed by two N, N, O tridentates 2-acetyl-pyridyl-isonicotinoylhydrazone
ligands, or by two N, O bidentate 2-acetyl-pyridyl-isonicotinoylhydrazone and two water molecules. Biological activity studies
reveal a moderate activity of complexes against gram-negative and gram-positive bacteria. 相似文献
14.
Jerzy Zak Mieczyslaw Lapkowski Stephane Guillerez Gerard Bidan 《Journal of Solid State Electrochemistry》2006,10(3):134-139
An existence of a new, stable oligomer state of the solid film is reported, which is produced under electrochemical conditions.
In this state, a formal charge exchanged in the redox process is about one-half of electron per oligomer molecule. The procedure,
which allows controlling precisely the amount of oligomer on the electrode surface, is proposed that together with the coulometric
evaluation of the electric charge provides the number of electrons involved in a redox process. This is demonstrated for a
case of α-monochloro-substituted regioregular sexi (3-octylthiophene) oligomer (6OTCl). The electrochemical results are discussed
together with UV–Vis–NIR spectroelectrochemical data obtained for both solution and solid phase that support the proposed
interpretation.
相似文献
Mieczyslaw LapkowskiEmail: |
15.
F. Yakuphanoglu A. Karadağ M. Şekerci 《Journal of Thermal Analysis and Calorimetry》2006,86(3):727-731
Thermal properties of the single crystals have been investigated by
thermogravimetry (TG) and differential scanning calorimetry (DSC) techniques.
The thermodynamic parameters such as activation energy and enthalpy and thermal
stability temperature of the samples were calculated from the differential
thermal analysis (DTA) and TG data. The activation energies for first peak
of DTA curves were found as 496.65 (for Cd–Pd) and 419.37 kJ mol–1
(for Zn–Pd). For second peak, activation energies were calculated 116.56
(for Cd–Pd) and 173.96 kJ mol–1 (for
Zn–Pd). The thermal stability temperature values of the Cd–Pd
and Zn–Pd compounds at 10°C min–1
heating rate are determined as approximately 220.7 and 203°C, respectively.
The TG results suggest that thermal stability of the Cd–Pd complex is
higher than that of the Zn–Pd complex. 相似文献
16.
J. Maul A. S. Brito A. L. M. de Oliveira S. J. G. Lima M. A. M. A. Maurera D. Keyson A. G. Souza I. M. G. Santos 《Journal of Thermal Analysis and Calorimetry》2011,106(2):519-523
Copper monoxide (CuO) was successfully obtained by microwave-assisted hydrothermal method, using different conditions—in a
solution without base, in a solution alkalinized with NaOH or with NH4OH. The powders were analyzed by thermal analysis (TG/DTA), X-ray diffraction (XRD), infrared spectroscopy, UV–Visible spectroscopy,
and scanning electronic microscopy. XRD results showed that CuO was obtained with monoclinic structure and without secondary
phases. Thermal analysis and infrared spectra indicated the presence of acetate groups on the powder surface. TG curves also
showed a mass gain assigned to the Cu(I) oxidation indicating that a reduction possibly occurred during synthesis. The high
and broad absorption band in the UV–Vis spectroscopy from 250 to 750 nm indicated the coexistence of Cu(II) and Cu(I), confirming
the Cu(II) reduction, inside the CuO lattice. It was also possible to confirm the Cu(II) reduction by a displacement of the
Me–O vibration bands observed in the IR spectra at around 500 cm−1. 相似文献
17.
Attila Gáspár István Bácsi Erika F. Garcia Mihály Braun Frank A. Gomez 《Analytical and bioanalytical chemistry》2009,395(2):473-478
The goal of this work was to increase the sensitivity of a UV–Vis spectrophotometer by decreasing the background noise and
lengthening the optical path. A microphotometer has been modified to precisely select very small parts of a microfluidic channel
pattern of a chip and to measure light absorbance on a magnified area of the selected part of the channel. The viability of
combining a projection microscope and a spectrophotometer for external absorbance measurements on disposable PDMS chips was
studied. Besides the external direct detection above a microfluidic channel, the optical pathlength was lengthened by detecting
in the region of the perpendicular exit port. Increasing the cross-sectional area of the zone of irradiation improved the
signal-to-noise ratio and the limits of detection (LOD). 相似文献
18.
C. R. Dockery A. R. Stefan A. A. Nieuwland S. N. Roberson B. M. Baguley J. E. Hendrix S. L. Morgan 《Analytical and bioanalytical chemistry》2009,394(8):2095-2103
Systematic designed experiments were employed to find the optimum conditions for extraction of direct, reactive, and vat dyes
from cotton fibers prior to forensic characterization. Automated microextractions were coupled with measurements of extraction
efficiencies on a microplate reader UV–visible spectrophotometer to enable rapid screening of extraction efficiency as a function
of solvent composition. Solvent extraction conditions were also developed to be compatible with subsequent forensic characterization
of extracted dyes by capillary electrophoresis with UV–visible diode array detection. The capillary electrophoresis electrolyte
successfully used in this work consists of 5 mM ammonium acetate in 40:60 acetonitrile–water at pH 9.3, with the addition
of sodium dithionite reducing agent to facilitate analysis of vat dyes. The ultimate goal of these research efforts is enhanced
discrimination of trace fiber evidence by analysis of extracted dyes.
Figure Fitted absorbance response surface for extraction of a direct dye, C. I. yellow 58, using a ternary solvent system. 相似文献
19.
Krzysztof Kurzak Iwona Kuźniarska-Biernacka Cristina Freire 《Structural chemistry》2010,21(2):377-383
The bis(N-2-pyridyl-salicylaldiminato)cobalt(II) complex ([Co(sap)2]), a reddish-pink crystalline compound has been characterized by elemental analysis, molar conductivity, cyclic voltammetry,
and Vis–NIR spectroscopy. Combination of all techniques indicates a tetrahedral geometry for the complex in solid state and
in the solvents used. Electronic spectroscopy was used to determine the ligand–field parameters as well as chromaticity coordinates;
for discrimination of color changes CIE and CIELAB color spaces have been applied. 相似文献
20.
Thaila T Kumararaman S 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,82(1):20-24
The nonlinear optical single crystals of doped sulphamic acid (SA) were grown from aqueous solution by doping with NaCl and KCl using slow evaporation method. Powder X-ray diffraction studies confirm that the grown crystals belong to orthorhombic system. The density and melting point measurements of the grown crystals were determined by floatation technique and capillary tube method, respectively. The range of optical transmittance was ascertained by recording the UV–Vis–NIR spectrum. Atomic absorption study reveals the presence of dopants in the doped crystals. The thermal analyses indicated that the doped SA crystals are more stable than pure crystals. The Vicker's microhardness studies revealed that the dopants increased the hardness of the crystals. SHG efficiency studies of the crystals are found to be increased in the presence of NaCl and KCl dopants. 相似文献