Miracle-dz/UniFAR-FTUs huggingface dataset:
Ultra‐thin SiO2 on Si IX: absolute measurements of the amount of silicon oxide as a thickness of SiO2 on Si

Results from a study conducted between National Metrology Institutes (NMIs) for the measurements of the absolute thicknesses of ultra‐thin layers of SiO2 on Si are reported. These results are from a key comparison and associated pilot study under the auspices of the Consultative Committee for Amount of Substance. ‘Amount of substance’ may be expressed in many ways, and here the measurand is the thickness of the silicon oxide layers with nominal thicknesses in the range 1.5–8 nm on Si substrates, expressed as the thickness of SiO2. Separate samples were provided to each institute in containers that limited the carbonaceous contamination to approximately < 0.3 nm. The SiO2 samples were of ultra‐thin on (100) and (111) orientated wafers of Si. The measurements from the laboratories which participated in the study were conducted using ellipsometry, neutron reflectivity, X‐ray photoelectron spectroscopy or X‐ray reflectivity, guided by the protocol developed in an earlier pilot study. A very minor correction was made in the different samples that each laboratory received. Where appropriate, method offset values attributed to the effects of contaminations, from the earlier pilot study, were subtracted. Values for the key comparison reference values (agreed best values from a Consultative Committee study) and their associated uncertainties for these samples are then made from the weighted means and the expanded weighted standard deviations of the means of these data. These results show a dramatic improvement on previous comparisons, leading to 95% uncertainties in the range 0.09–0.27 nm, equivalent to 0.4–1.0 monolayers over the 1.5–8.0 nm nominal thickness range studied. If the sample‐to‐sample uncertainty is reduced from its maximum estimate to the most likely value, these uncertainties reduce to 0.05–0.25 nm or ∼1.4% relative standard uncertainties. The best results achieve ∼1% relative standard uncertainty. It is concluded that XPS has now been made fully traceable to the SI, for ultra‐thin thermal SiO2 on Si layers, by calibration using wavelength methods in an approach that may be extended to other material systems. © Crown copyright 2009. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
Hydrodynamics and Mass Transfer in Gas‐Liquid‐Solid Circulating Fluidized Beds

Although extensive work has been performed on the hydrodynamics and gas-liquid mass transfer in conventional three-phase fluidized beds, relevant documented reports on gas-liquid-solid circulating fluidized beds (GLSCFBs) are scarce. In this work, the radial distribution of gas and solid holdups were investigated at two axial positions in a GLSCFB. The results show that gas bubbles and solid particles distribute uniformly in the axial direction but non-uniformly in the radial direction. The radial nonuniformity demonstrates a strong factor on the gas-liquid mass transfer coefficients. A local mass transfer model is proposed to describe the gas-liquid mass transfer at various radial positions. The local mass transfer coefficients appear to be symmetric about the central line of the riser with a lower value in the wall region. The effects of gas flow rates, particle circulating rates and liquid velocities on gas-liquid mass transfer have also been investigated.
Characterization of Thermally Stable AB-type Poly(ether-amide)s Derived from AB-type Monomers by Fluoro Displacement Reaction

Two AB-type monomers 4-fluoro -N-(4-(2-(4-hydroxyphenyl) propan-2-yl) phenyl) benzamide and 4-fluoro -N-(5-hydroxy naphthyl) benzamide were synthesized. The AB-type poly(ether-amide)s (PEAs) were derived by self-polymerization via the nucleophilic aromatic displacement reaction of AB-type monomers. The structure of AB-type monomers and PEAs were confirmed by FT-IR and H1-NMR spectroscopy. The PEAs were characterized by TGA, DSC, XRD, solution viscosity and solubility. X-ray diffraction studies indicated that the poly (ether-amide)s were amorphous. Poly(ether-amide)s exhibited excellent thermal stability and solubility. All the PEAs were readily soluble at room temperature in polar aprotic solvent DMSO, NMP and DMAc and also in less polar solvents such as m-cresol and pyridine.
Kinetic Analysis and Optimization for the Catalytic Esterification Step of PPT Polymerization

Awell-validated kinetic scheme has been studied for PPT, poly(propylene terephthalate) polymerization process in batch and semi-batch mode with tetrabutoxytitanium (TBOT), a proven catalyst. Optimization study and analysis for PPT are rare, as the industrial relevance of PPT just became vibrant due to the commercial availability of one of its monomers in industrial scale in the recent past. Correctness of the analysis is checked by a new approach and parameters for the model are estimated from available experimental data. Solubility of terephthalic acid (TPA) is less in reaction medium and this effect is also considered along with the reaction scheme. Several simulations have been performed to see various process dynamics and this ultimately helps in formulating optimization problems. Using recently developed and well tested real-coded non+dominated sorting genetic algorithm-II, a state-of-the art evolutionary optimization algorithm, a couple of three objective optimization problems have been solved and corresponding Pareto sets are presented. Results show remarkably promising aspects of productivity enhancement with an improvement in product quality. Sensitivity analysis for relatively uncertain solubility parameter is also performed to estimate its effect over the proposed optimal solutions.
Cyclic voltammetric study of Co-Ni-Fe alloys electrodeposition in sulfate medium

Electrochemical technique has been used to study the electrodeposition of cobalt, nickel, iron and Co-Ni-Fe alloy on indium tin oxide (ITO) coated glass substrate. To obtain the nucleation mechanism, cyclic voltammetry is used to characterize the Co-Ni-Fe system. The scanning rate effect on the deposition process was investigated. Deposition of single metal occurs at potential values more positive than that estimated stability potential. Based on the cyclic voltammetry results, the electrodeposition of cobalt, nickel, iron and Co-Ni-Fe alloy clearly show that the process of diffusion occurs is controlled by the typical nucleation mechanism.
Optical Sensors for the Determination of Heavy Metal Ions

Diese Arbeit beschreibt die Entwicklung optischer Sensoren fur die Bestimmung von Schwermetallionen in wassrigem Milieu. Ein Sensorprinzip fur die selektive Bestimmung von Kupfer(II) basierend auf der Messung von Fluoreszenzintensitaten wird vorgestellt. Dieses wird anschliesend durch eine Referenzierungsmethode optimiert. Ferner wird ein neues Sensorprinzip im Mikrotiterplattenformat fur die gleichzeitige Bestimmung mehrerer Ionen mit Hilfe von bildgebenden Verfahren prasentiert.
Substrate Induced Thermal Decomposition of Perfluoro-Pentacene Thin Films on the Coinage Metals

The thermal and chemical stability of perfluoropentacene (PFP) thin films grown by organic molecular beam deposition onto the (111)-oriented surfaces of the coinage metals copper, silver, and gold have been studied by means of temperature dependent X-ray photoelectron spectroscopy (XPS) and Near-Edge X-ray absorption fine structure spectroscopy (NEXAFS). Under vacuum conditions, PFP multilayers are completely desorbed at 425 K while molecules in contact with the Au(111) surface remain intact up to 500 K. By contrast, PFP that is in contact with Cu(111) is distinctly distorted and becomes partially defluorinated already upon thermal desorption of multilayers. A pronounced defluorination of PFP also takes place on Ag(111) at temperatures around 440 K, while further heating causes a complete cracking and defluorination. Additional measurements carried out on a regularly stepped silver surface demonstrate that steps are active sites that promote defluorination already at lower temperatures. van der Waals corr.
Ionic Liquids in Oxygen Compression

Ionic liquids are still a relatively new and very promising class of substances which have received increased research attention in recent years. Due to their unique physical and chemical properties these compounds are ideal for use in industrial applications and also offer a variety of very interesting possibilities in process technology, with a high potential of increasing performance and reducing investment and operating costs [1]. Ionic liquids are remarkable for their high chemical inertness and good lubricity. Therefore, one very promising application is the lubricated compression of oxygen as an alternative to the dry compression technique that has to be used because of the extremely high reactivity of pure oxygen with organic lubricating media. A screening of the relevant parameters including thermal stability, flammability, chemical inertness to pure oxygen, corrosiveness, tribological behavior and oxygen solubility was performed. Based on the results obtained, the most suitable ionic liquid was identified and used in a screw compressor setup that achieves a final pressure of 30 bar with a delivery volume of up to 200 Nm 3 /h.
How accurate are molecular mechanics predictions for fullerenes? A benchmark comparison with Hartree-Fock self-consistent field results

As research into the growing family of fullerene compounds continues to expand, theoreticians making predictions about these large carbon clusters are interested in reliable approaches to reduce the computational expense of calculations. Here we show that an empirical method, molecular mechanics (MM3), can be effectively used to optimize the geometries of fullerenes and consequently reduce the time required for more elaborate quantum mechanical calculations. Equilibrium structures and heats of formation were predicted for 22 fullerences ranging from C[sub 28] to C[sub 120] using MM3. The MM3 geometries are found to be in good agreement with those obtained by the minimum basis Hartree-Fock self-consistent field (SCF) method. However, the heats of formation obtained with MM3 and SCF are quite different. At the MM3 optimized geometry, an SCF energy point was calculated for each structure and found to be very close to the fully optimized SCF energy. This procedure yields accurate energy differences between isomers at a fraction of the computational cost. We propose other ways of using MM3 to speed ab initio calculations as well. 40 refs., 7 figs., 4 tabs.
Hyperbranched pyridylphenylene polymers based on the first-generation dendrimer as a multifunctional monomer

An A6 + B2 approach was applied for the first time to synthesize novel hyperbranched pyridylphenylene polymers by Diels–Alder cyclocondensation reaction. For this, the first-generation pyridylphenylene dendrimer with six ethynyl functionalities (A6) was used as a branching core for the molecule growth. The phenyl-substituted bis(cyclopentadienone)s (B2) of different structures were used as co-monomer in the reaction. A careful choice of reaction conditions allowed us to obtain high molecular weight polymers without undesirable gelation. The molecular weight of the polymers varied in the range of 10 800–80 100 with a polydispersity degree of 1.69 to 4.07 according to SEC analysis. The 1H and inverse-gated decoupling 13C NMR combined with heteronuclear single quantum correlation and heteronuclear multiple bond correlation measurements were used to estimate the branching degree of the polymers synthesized.
Characterization of the biocide polyhexamethylene biguanide by matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry

The biocide polyhexamethylene biguanide (PHMB) has been characterized by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Previously, no method has been able to provide a detailed structural characterization of PHMB. MALDI-TOF MS was able to detect PHMB oligomers with n ≤ 6. Six different PHMB product types were identified, which possess combinations of amine, cyanoamine, guanidine, or cyanoguanidine end-groups. Postsource decay (PSD) fragmentation was used to confirm the correct assignment of PHMB structure for the dominant PHMB molecular ion. MALDI-TOF MS analysis of a 15N-labeled PHMB confirmed the correct assignment of PHMB molecular ions, and also indicated the existence of a polymerization–depolymerization equilibrium during melt polymerization of the polymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4928–4936, 2006
Equation of state predictions of sorption isotherms in polymeric materials

The ability of the Sanchez-Lacombe equation of state to predict the solubility of small penetrants in rubbery polymer matrices, over a wide range of ambient pressures, is examined critically. The solute chemical potential and, in turn, the resulting predicted isotherms are found to depend strongly on solute equation of state parameter values and on the mixing parameter for polymer-penetrant interactions. The isotherms are less sensitive to polymer equation of state parameters. In the sorption of organic vapors into polymers, the model does not describe well the sorption isotherms at high values of penetrant activity. The model appears to describe sorption isotherms most accurately when both polymer and penetrant equation of state parameters are determined from pure component properties, in the same temperature and pressure range as the sorption data, and when a mixing parameter is used to adjust the fit of the model to the data. © 1993 John Wiley & Sons, Inc.
Spectrofluorimetric Determination of Three Pharmaceutical Thiocompounds and Allopurinol Using Mercurochrome

Abstract A new, simple and sensitive fluorimetric method for the determination of three pharmaceutical thiocompounds: cimetidine, thiabendazole and carbimazole, and also allopurinol, has been presented. The method is based on the fluorescence quenching of mercurochrome (MER) in an aqueous alkaline medium. Calibration graphs correlating the fluorescence difference (Fo-F) or the fluoresence ratio (Fo/F) of MER before (Fo) and after (F) quencher addition versus the concentration of the latter are linear. Such linearity permitted the successful application of
Ternary single‐source precursors for polycrystalline thin‐film solar cells

The development of thin-film solar cells on flexible, lightweight, space-qualified substrates provides an attractive cost solution for fabricating solar arrays with high specific power (W kg−1). The use of a polycrystalline chalcopyrite absorber layer for thin-film solar cells is considered as the next generation in photovoltaic devices. At NASA GRC we have focused on the development of new single-source precursors (SSPs) and their utility to deposit the chalcopyrite semiconducting layer (CIS) onto flexible substrates for solar-cell fabrication. The syntheses and thermal modulation of SSPs via molecular engineering are described. Thin-film fabrication studies demonstrate that the SSPs can be used in a spray chemical vapor deposition process for depositing CIS at reduced temperatures, and result in electrical properties that are suitable for photovoltaic devices. Copyright © 2002 John Wiley & Sons, Ltd.
Cardiovascular effects induced by α‐terpineol in hypertensive rats

The antihypertensive and antioxidant effects of α-terpineol on hypertensive rats were evaluated in this study. Hypertension was induced in male Wistar rats by oral administration of the NG-nitro-L-arginine methyl ester (L-NAME) 50 mg/kg body weight/day) in drinking water for 1 week. Rats with mean arterial pressure > 140 mmHg were considered hypertensive. In order to evaluate the α-terpineol effect on haemodynamic parameters, rats were treated once a day with different doses of α-terpineol (25, 50, or 100 mg/kg/day) or vehicle for one week. After this time, blood samples were collected and activities of antioxidant enzymes were assessed. Furthermore, the vasorelaxant effect of α-terpineol was also assessed in mesenteric artery rings. Oral administration of α-terpineol was able to reduce mean arterial pressure in up to 38.15 ± 8.7 mmHg. In mesenteric artery rings, α-terpineol (10−9–10−2 M) induced vascular endothelium independent vasodilatation. In addition, rats treated with α-terpineol showed alterations in biochemical parameters indicating an antioxidant effect. Such results suggest that α-terpineol is able to reduce arterial pressure, possibly due to a decrease of vascular resistance, and restore enzymatic antioxidants in L-NAME-induced hypertensive rats. Copyright © 2013 John Wiley & Sons, Ltd.
Thermal Lag, Fusion, and the Compensation Effect during Biomass Pyrolysis†

Results from a numerical model for endothermic biomass pyrolysis, which includes both high activation energy kinetics and heat transfer across a boundary layer to the reacting solid particle, are presented. The model accounts for conventional thermocouple thermal lag and unconventional thermal lag due to heat demand by the chemical reaction (which is governed by Arrhenius kinetics). Biomass fusion, first identified quantitatively by Lede and Villermaux, is shown to be a manifestation of severe thermal lag that results from the chemical reaction heat demand. Over the wide range of conditions studied, the true substrate temperature remains almost constant during pyrolysis, as is the case with compounds undergoing fusion or sublimation at constant pressure. A simple algebraic model, whose derivation presupposes the idea that biomass pyrolysis mimics the melting of a block of ice, accurately predicts the maximum value of thermal lag during pyrolysis. Unidentified thermal lag in TGA experiments lowers the valu.
Reaction products of 2-aminobenzenethiol with some β-diketones

2-Aminobenzenethiol undergoes condensation reactions with several β-diketones (CH3, CF3 and C6H5 substituents) to form benzothiazolines. Conversion to benzothiazines and benzothiazoles occurs in some instances, as documented by the isolation and spectroscopic characterization of the products.
Characterization of PECVD grown porous SiO2 thin films with potential application in an uncooled infrared detector

Plasma-enhanced chemical vapor deposition (PECVD) technology was considered as an excellent thin film deposition dry process in semiconductor device fabrication. Porous SiO2 film as a promising thermal insulation layer used in uncooled infrared detectors was grown directly by PECVD technology. The microstructure and elemental composition of the film were characterized by AFM, EDS, SEM and XPS. The porosity of the film was assessed according to the refractive index measured by ellipsometery. A prototype pyroelectric uncooled detector coated with a porous SiO2 film was evaluated.
A study of the Debye-Stokes-Einstein law in supercooled fluids

The reorientation of a nearly spherical paramagnetic tracer dissolved in supercooled o-terphenyl is studied by electron spin resonance in the range 200 K 300 K the rotational correlation time follows the Debye - Stokes - Einstein law. On decreasing the temperature, the rotational motion of the probe and the viscosity decouple. In particular, in the region around T = 290 K it is found that with .
A novel approach to determine leucomalachite green and malachite green in fish fillets with surface‐enhanced Raman spectroscopy (SERS) and multivariate analyses

The use of illegal fish drugs, such as malachite green (MG) in aquaculture has raised growing concerns over the safety of aquatic food products, and sensitive and rapid methods for detection of these drugs in fish muscle are much needed. Simplified extraction methods coupled with surface-enhanced Raman spectroscopy were used for analysis of MG and its metabolite leucomalachite green (LMG) in tilapia fillets containing 0–50 ng g−1 LMG or MG. Principal component analysis and partial least squares (PLS) regression were used for spectral data analyses. High sensitivity (MG or LMG could be detected at 1–2 ng g−1 levels) and PLS models with good predictability [root mean square error of validation (RMSEV) = 1.97–2.21 ng g−1, R2 = 0.984–0.988] were possible with suitable sample extraction methods. The simplest extraction method developed provided an RMSEV of 9.32 ng g−1 and R2 of 0.788, and although this was not ideal, detection of MG and LMG at 5 ng g−1 level with this method could reduce sample throughput time and provide for faster detection of LMG and MG. Copyright © 2012 John Wiley & Sons, Ltd.
Allelopathic Effects of Chromolaena Odorata L. (R. M. King and Robinson – (Awolowo Plant’)) Toxin on Tomatoes (Lycopersicum esculentum Mill)

Allelopathic effects of Chromolaena odorata L. (R. M. KING AND ROBINSON) aqueous leaf extract and residues incorporated in the soil on the growth and water status of Lycopersicon esculentum Mill were studied. Significant growth reductions in Lycopersicon esculentum were observed from additions of C. odorata aqueous – leaf extract at concentrations as low as 1g fresh weight in 40ml of water. Reduction in growth was accompanied by decreases in leaf water potential. Incorporation of C. odorata leaf material into the soil in which L esculentum Mill seedlings were germinated and grown caused significant depression in growth over the 2-week test period with addition of 2g residue to 80g soil. Allelochemicals released from C. odorata plants and residue are suggested as a possible explanation for yield reductions in crops in fields where C. odorata plants are present. One mechanism of toxic action on seedlings involved interference with water balance
High-resolution spectroscopy of difference and combination bands of SF6 to elucidate the ν3 + ν1 − ν1 and ν3 + ν2 − ν2 hot band structures in the ν3 region

The strong infrared absorption in the ν3 S–F stretching region of sulphur hexafluoride (SF6) near 948 cm−1 makes it a powerful greenhouse gas. Although its present concentration in the atmosphere is very low, it is increasing rapidly, due to industrial pollution. The ground state population of this heavy species is only 32% at room temperature and thus many hot bands are present. Consequently, a reliable remote-sensing spectroscopic detection and monitoring of this species require an accurate modelling of these hot bands. We used two experimental set-ups at the SOLEIL French synchrotron facility to record some difference and combination bands of SF6: (1) a new cryogenic multiple pass cell with 93 m optical path length and regulated at 163 ± 2 K temperature and (2) the Jet-AILES supersonic expansion set-up. With this, we could obtain high-resolution absorption spectra of the ν3 − ν1, ν3 − ν2, ν1 + ν3 and ν2 + ν3 bands at low temperature. These spectra could be assigned and analysed, thanks to the SPVIEW and XTDS computer programs developed in Dijon. We performed two global fits of effective Hamiltonian parameters. The first one is a global fit of the ground state, ν2, ν3, ν3 − ν2, ν2 + ν3, 2ν3 and 2ν3 − ν3 rovibrational parameters, using the present spectra and previous infrared, Raman and two-photon absorption data. This allows a consistent refinement of the effective Hamiltonian parameters for all the implied vibrational levels and a new simulation of the 2ν3 + ν2 − ν2 hot band. The second global fit involves the present ν3 − ν1 and ν1 + ν3 lines, together with previous ν1 Raman data, in order to obtain refined ν1 parameters and also ν1 + ν3 parameters in a consistent way. This allows to simulate the ν3 + ν1 − ν1 hot band.