Miracle-dz/UniFAR-FTUs huggingface dataset:
Multiple linker Half-squarylium Dyes for Dye-Sensitized Solar Cells; Are Two Linkers Better than One?

The synthesis and full characterization of new half-squaraine dyes (Hf-SQ) containing two or three carboxylate-based linker units is reported and these dyes tested in dye-sensitized solar cell (DSC) devices. The data show improved device efficiency for a Hf-SQ dye with two linkers (η = 5.5%) compared to the highest efficiency Hf-SQ previously reported which had only a single linker (η = 5.0%); this is mainly due to improved Voc. To understand the effects of using multiple dye linker groups, device I–V data have been correlated with single crystal X-ray structural analysis and dye electrical properties (both in solution and adsorbed to TiO2) using UV-visible and ATR-IR spectroscopy along with cyclic voltammetry, and also theoretical studies using density functional theory (DFT) calculations. These data show that positioning the linkers near the dye LUMO and so that this enables complete linker chemisorption are key factors for device performance.
Vanadium Redox-Flow-Battery (VRFB) System Electrolyte Preparation with Reducing Agents

To meet the increasing energy demand, research effort has been devoted to the development of new and renewable energy resources. A Redox-Flow-Battery (RFB) is attractive due to its applications in large-scale energy storage [1]. RFB is a type of rechargeable battery consisting of two tanks of soluble redox reactants, which determine the system energy storage capacity, and the battery stack, which determines the system power capacity. Since the Iron/Chromium (Fe/Cr) RFB was initiated by NASA in 1970s, various redox chemistries have been developed and evaluated, such as polysulphide/bromine RFB, all-vanadium RFB, and others [2]. Among these RFB systems, vanadium redox flow batteries (VRFB) are considered especially attractive, since the electrochemically active reactants are vanadium species in four different oxidation states in both electrolyte solutions. As such, the undesired crosscontamination of anolyte and catholyte through the cell separator is eliminated, although reactant crossover still results in coulombic-efficiency losses.
Photoabsorption in carbon monoxide: Stieltjes–Tchebycheff calculations in the separated‐channel static‐exchange approximation

Theoretical investigations of total and partial‐channel photoabsorption cross sections in carbon monoxide are reported employing the Stieltjes–Tchebycheff (S–T) technique and separated‐channel static‐exchange calculations. Pseudospectra of discrete transition frequencies and oscillator strengths appropriate for individual excitations of each of the six occupied molecular orbitals are constructed using Hartree–Fock core functions and normalizable Gaussian orbitals to describe the photoexcited and ejected electrons. Use of relatively large basis sets of compact and diffuse functions insures the presence of appropriate discrete Rydberg states in the calculations and provides sufficiently dense pseudospectra for the determination of convergent photoionization cross sections from the S–T technique. The calculated discrete vertical electronic excitation spectra are in very good agreement with measured band positions and intensities, and the partial‐channel photoionization cross sections are in correspondingly g.
Spectroelectrochemical Study on the Electrooxidation in Aqueous Medium of some 1,4‐Dihydropyridines: Effects of Substitution in 1‐Position and 4‐Position

Spectroelectrochemical and HPLC characterization of the electrochemical oxidation in aqueous medium of a series of six N-1 and C-4 substituted 1,4-dihydropyridines is presented. Based on the analysis of spectra obtained by in situ spectroscopic measurements it was possible to detect the generation of final oxidation products, which resulted in differences depending of the nature of the substitution on the nitrogen in the dihydropyridine ring. Controlled potential electrolysis (CPE) in aqueous medium was followed by the HPLC technique using EC and PDA detectors. This latter resulted adequately to follow the parent 1,4-DHP derivatives and their respective oxidation products. Electrochemical oxidation of parent N-H substituted 1,4-dihydropyridines generated the corresponding neutral pyridine derivative as final oxidation product. However, the N-ethyl substituted 1,4-dihydropyridine derivatives gave rise to the pyridinium salt derivatives.
Quantitative analysis of aluminium alloys by low-energy, high-repetition rate laser-induced breakdown spectroscopy

With the aim of reducing the dimensions of a laser-induced breakdown spectroscopy (LIBS) apparatus for building a portable instrument, a diode-pumped Nd:YAG mini-laser at high repetition rate was tested as an excitation source for the quantitative analysis of aluminium alloy samples. Moreover, LIBS spectra acquired by using an ICCD-echelle spectrometer detection system were compared with those obtained by a traditional spectrometer coupled to a non-intensified linear array detector. Calibration curves were built and limits of detections were calculated using both detection systems for magnesium, silicon, copper, titanium, manganese, nickel and iron. The results were compared with those obtained by recently proposed LIBS systems based on the use of microchip lasers.
Adsorption of Some Textile Dyes by Hexadecyltrimethylammonium Bentonite

In this study, hexadecyltrimethylammonium (HDTMA) bentonite was synthesized by placing alkylammonium cation onto bentonite. Adsorption of some textile dyes such as Everdirect Supra Yellow PG, Everdirect Supra Orange 26 CG, Everdirect Supra Rubine BL, Everdirect Supra Blue 4BL and Everdirect Supra Red BWS on Na-bentonite and HDTMA-bentonite was investigated. While the Na-bentonite had no affinity for the dyes, the HDTMA-bentonite showed significant adsorption from aqueous solution. The Langmuir and Dubinin-Rasdushkevich (D-R) isotherm equations were applied to the data and values of parameters of these isotherm equations were evaluated. The mean energy of adsorption, E, was also calculated from the adsorption energy constant K' values determined from the D-R isotherm equation.
A comparative study of TiO2 and surface-treated TiO2 nanoparticles on thermal and mechanical properties of poly(ε-caprolactone) nanocomposites

Polymer/inorganic nanocomposites were significant hybrid materials because of their unique properties. The surface of bare nanoparticles (b-TiO2) was modified by aminopropyl trimethoxy silane to obtain grafted TiO2 (g-TiO2) nanoparticles for the improvement of nanoparticles dispersion. The b-TiO2 and resulting g-TiO2 nanoparticles were introduced into poly(e-caprolactone) (PCL) matrix to prepare PCL/TiO2 nanocomposites by in situ polymerization. The effects of b-TiO2 and g-TiO2 nanoparticles on the structure, morphology, and properties of nanocomposites were characterized and compared. The results showed that the crystalline structure of PCL matrix was not affected significantly by adding b-TiO2 or g-TiO2 nanoparticles. The g-TiO2 nanoparticles had a finer dispersion and better compatibility than bare TiO2. The introduction of g-TiO2 into PCL matrix increased the crystallization temperature and improved thermal stability of the nanocomposites with respect to untreated TiO2. The surface-treated nanoparticles played an important role in strengthening mechanical properties of the nanocomposites because of its well dispersion and strong interfacial interaction between the nanoparticles and PCL matrix. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Measuring Stable Carbon Isotope Ratios of Small Samples of Soil‐Respired Carbon Dioxide in a Maize–Soybean Rotation

Abstract Stable carbon (C) isotope analysis of soil‐respired carbon dioxide (CO2) has proven to be useful in studies that attempt to separate heterotrophic (i.e., bulk soil microbial) respiration from autotrophic (i.e., root and root‐associated microbial) respiration. Many studies have relied upon the use of a site that has been under long‐term cultivation of plants using a single photosynthetic pathway (C3 or C4) whereby plants and soils have contrasting δ13C signatures. Relatively large gas samples are normally collected in these studies, and CO2 is concentrated in the laboratory prior to δ13C analysis, thus limiting the number of samples that can be handled at one time. The present study investigated the use of a maize–soybean rotation in which roots were excluded from small areas within the site. Small (12‐mL) gas samples containing soil‐respired CO2 were analyzed without further treatment using an automated cryogenic trap in line with a continuous‐flow delivery system in which a gas chromatography column was interfaced with an isotope ratio mass spectrometer.
Laccase-Nafion Based Biosensor for the Determination of Polyphenolic Secondary Metabolites

A laccase-based biosensor was developed by specific enzyme adsorption on screen-printed working electrodes of DROPSENS cells, and stabilized with Nafion 0.1% membrane. The electrode was characterized with respect to response time, sensitivity, linear range, detection limit, pH dependence, interferences, and long-term stability. The tested substrates were catechol, rosmarinic acid, caffeic acid, chlorogenic acid, and gallic acid. The optimized biosensor proved the following characteristic performances: the apparent Michaelis Menten calculated considering rosmarinic acid substrate 8.3 × 10−6 mol L−1 (r = 0.995, n = 6); the dynamic range of biosensor response for rosmarinic acid 7 × 10−7 − 1.5 × 10−6 mol L−1; the detection limit for rosmarinic acid 1.19 × 10−7 mol L−1 (RSD = 1.08%, n = 3). It was noticed that the biosensor reaches systematically 90% to 94.3% from the response obtained by LC-DAD-ESI-MS for real samples.
Supercritical Fluid Extraction of Pesticide Residues from Strawberries

A supercritical fluid extraction (SFE) method for the determination in strawberries of a number of commonly used organochlorine insecticides, organophosphorus pesticides, and dichloroanilide fungicides is described. Gas chromatography was used to examine the extracts, with both electron-capture detection and either flame photometric or nitrogen phosphorus detection. Confirmation was performed by gas chromatography-mass spectrometry. The analytes were extracted with supercritical carbon dioxide at 4000 psi and 50 °C with a run time of 20 min, which corresponded to an extraction volume of 20-30 mL of carbon dioxide. In developing the method, the operating parameters of temperature, pressure, extraction time, collection solvent, and sample preparation were optimized. Recoveries ranged from 74 to 126% (with the exception of iprodione), and a method precision of ±3-18% was obtained for spiking levels of 0.08-3.7 mg/kg. The method was validated for the following organochlorine insecticides and organophosphorus pesticides: aldrin, dichloran, dieldrin, p,p'-DDE(TDE), p,p'-DDD, p,p'-DDT, α-endosulfan, β-endosulfan, endosulfan sulfate, diazinon, dichlorvos, ethion, malathion, methyl parathion, methyl pirimiphos, mevinphos E+Z, and parathion; and the following dichloroanilide fungicides: iprodione, procymidone, and vinclozolin. The SFE procedure was quicker, more environmentally friendly, and more cost effective than the traditional solvent extraction methods.
Surface Atomic Structure and Growth Mechanism of Monodisperse {1 0 0}-Faceted Strontium Titanate Zirconate Nanocubes

The highly sensitive and selective properties of monodisperse faceted nanocrystals inherently stem from the atomic and electronic structures on the faceted surfaces. For elemental nanocrystals, the atomic structure on the surfaces is merely determined by the geometric shape itself. However, for compound materials such as alloys and complex oxides, atomic details on the faceted surfaces need to be studied on the atomic level. Here, we demonstrate that the surface atomic structure of faceted nanocrystals of complex oxides, {1 0 0}-faceted strontium titanate zirconate nanocubes, can be unambiguously resolved by aberration-corrected scanning transmission electron microscopy. The resolved surface atomic details reveal a layerwise growth process of the nanocubes, thereby allowing an in-depth understanding of the growth mechanism.
Biofiltration of a styrene/acetone vapor mixture in two reactor types under conditions of acetone overloading

BACKGROUND: Evaluation of the biodegradation interactions between styrene and acetone, two typical paint solvents and vapor phase pollutants differing in water solubility and biodegradability, was conducted both in a trickle bed reactor (TBR) and a biofilter (BF). The loading rate experiments were performed by increasing the acetone concentration in the inlet air while keeping the styrene concentration and loading rate constant. RESULTS: At acetone loading rates (OLAC) between 25 and 35 gc m−3 h−1, the BF featured greater steady state performance characteristics for styrene degradation. At OLAC between 35 and 48 gc m−3 h−1, a decline of removal efficiency (RE) was observed for both pollutants, due to the system's overloading with acetone. Increasing OLAC above 52-55 gc m−3 h−1 in both reactors resulted in drifts of RE and EC over time to much lower values. A step-drop of acetone loading rate back to OLAC of 3 gc m−3 h−1 (gc denotes grams of carbon) resulted in lag periods lasting for several hours. CONCLUSIONS: Two important issues inherent for acetone biofiltration, e.g., from paint booths or polystyrene production, were identified: (1) poor performance at high loadings of this aggressive solvent and (2) acetone back-stripping into the air following periods of high overloading. Copyright © 2012 Society of Chemical Industry
Microwave synthesis and single-crystal-to-single-crystal transformation of magnesium coordination polymers exhibiting selective gas adsorption and luminescence properties

A series of new magnesium coordination polymers, [Mg2(BTEC)(H2O)4]·2H2O (1), [Mg2(BTEC)(H2O)6] (2), and [Mg2(BTEC)(H2O)8] (3) (BTEC = 1,2,4,5-benzenetetracarboxylate anion), were synthesized from magnesium nitrate and 1,2,4,5-benzenetetracarboxylic acid with variable ratios of organic base under microwave-assisted solvothermal reactions at the temperature of 180 (1) or 150 °C (2 and 3). The results from crystal structure analysis showed that 1 was a 3D metal–organic framework, 2 a 2D layer, and 3 a 1D ladder structure. In addition, heating 1 at the temperature of 150 °C would convert it to 1a which can be a novel single-crystal-to-single-crystal transformation of coordination polymer. Single crystal of 1a has a new 3D structure with formula [Mg15(BTEC)6(HBTEC)2(H2O)12]·4H2O, containing unsaturated magnesium sites. Further gas adsorption experiments revealed that 1a undergoes a highly selective sorption of hydrogen instead of nitrogen gases. Photoluminescence studies also displayed that 1a emits extra strong green luminescence around 510 nm under the excitation of ultraviolet light.
An Efficient and Recycling Catalyst for the One-Pot Three-Component Synthesis of Substituted 3,4-Dihydropyrimidin-2(1H)-ones

The Biginelli one-pot three-component cyclocondensation was applied in this work to prepare 3,4-dihydropyrimidinone and its analogues using the first derivative of lead, Pb(NO3)2, as a recycling catalyst, from a diversity of aromatic aldehydes, β-ketoesters and urea. The reaction was carried out in refluxing acetonitrile and afforded the target molecules in good to excellent yields. The method offers several advantages including high yields of the products, short reaction times and easy experimental workup procedure
Towards the engineering of enantioselective properties of supported platinum catalysts

Understanding the sub-molecular structure of conformationally complex adsorbed molecules is still a difficult task for experimentalists interested in the structure of modified surfaces, therefore first principles calculations can be a fundamental tool for the investigation of structural details otherwise impossible to identify. Density functional theory (DFT) calculations of the adsorption of cinchonidine (CD) and O-phenyl-cinchonidine (OPhCD) have been performed, using large metal clusters to simulate the metal surface and a zero order regular approximation (ZORA) Hamiltonian to account for relativistic effects due to the heavy nuclei involved. The local geometry of chiral surface sites formed by CD was investigated in detail and discussed in relation to the reaction of enantioselective hydrogenation of activated ketones on cinchona modified platinum. Also, the relevant conformations of OPhCD were investigated and the resulting structure of the chiral sites is discussed and compared to those obtained for the parent alkaloid CD. The adsorption behavior on platinum of a series of substituted anisoles was also investigated, in order to evince the effect that phenyl substitution might have on the relative proportion of surface conformers in substituted OPhCD ethers, that have been shown to possess interesting enantioswitching properties when used as surface modifiers in the enantioselective hydrogenation of activated ketones on cinchona alkaloid modified platinum. A correlation between conformational distribution of the modifiers and the selectivity of the catalyst is proposed.
Removal of Phenol by Immobilization of Trametes versicolor in Silica–Alginate–Fungus Biocomposites and Loofa Sponge

Fil: Carabajal, Maira Lia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Micologia y Botanica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micologia y Botanica; Argentina
A Study on in vitro Anthelmintic Activity of Aqueous and Alcoholic Extracts of Memecyclon malabaricum Leaves against Pheritima posthuma

Aqueous and ethanol extracts from the leaves of Memecyclon malabaricum were investigated for their anthelmintic activity against Pheritima posthuma. Three concentrations (20, 40, 60 mg/ml) of each extracts were studied in activity, which involved the determination of time of paralysis and time of death of the worms. Both the extracts exhibited highly significant anthelmintic activity at highest concentration of 60 mg/ml. Piperazine citrate was included as standard reference and normal saline as control. The anthelmintic activity of aqueous and ethanol extracts of Memecyclon malabaricum has therefore been demonstrated for the first time.
Laser-induced Fluorescence Triple-integration Method Applied to Hydroxyl Concentration and Fluorescence Lifetime Measurements

We report quantitative hydroxyl concentrations obtained by using a new laser-induced fluorescence triple-integration method (LIFTIME), which is capable of rapid and continuous fluorescence lifetime measurements via a unique photon-counting technique. LIFTIME has been convolved with picosecond time-resolved laser-induced fluorescence to permit the rapid monitoring of instantaneous species concentrations in flames. Here, LIFTIME is used to measure hydroxyl concentrations and fluorescence lifetimes at a sampling rate of 1 Hz in eight premixed laminar flat flames and in one laminar opposed flow diffusion flame. Fluorescence lifetimes as a function of axial position are generally obtained with less than 5% uncertainty, while concentrations at the same locations are obtained with less than 10% uncertainty (95% confidence interval). The hydroxyl concentration measurements are shown to agree well with modeling predictions and with previous laser-saturated fluorescence measurements. The measurements are also compa.
Structural support of the external tubes in double-wall carbon nanotubes

High-pressure Raman studies of double-wall carbon nanotubes (DWCNTs) and their parent single-wall carbon nanotubes provide experimental evidence of the structural support of carbon nanotubes due to the encapsulation of smaller diameter tubes in their interior. The structural support is manifested by the reduced slope of the radial breathing mode frequency of the external tubes in DWCNTs, which further decreases at higher pressures as the inner–outer tube (intratube) interaction increases.
Influence of the electrokinetic behaviors of abrasive ceria particles and the deposited plasma-enhanced tetraethylorthosilicate and chemically vapor deposited Si_3N_4 films in an aqueous medium on chemical mechanical planarization for shallow trench isolation

The effects of the electrokinetic behavior of abrasive ceria particles suspended in an aqueous medium and the deposited plasma-enhanced tetraethylorthosilicate (PETEOS) and chemical vapor deposition (CVD) Si_3N_4 films on chemical mechanical planarization (CMP) for shallow trench isolation were investigated. The colloidal characteristics of ceria slurries, such as their stability and surface potential, in acidic, neutral, and alkaline suspensions were examined to determine the correlation between the colloidal properties of ceria slurry and CMP performance. The surface potentials of the ceria particles and the PETEOS and CVD Si_3N_4 films in an aqueous suspending medium were dependent on the pH of the suspending medium. The differences in surface charges of ceria particles and the PETEOS and CVD Si_3N_4 films have a profound effect on the removal rate and oxide-to-nitride selectivity of CMP performance.
Diffusion in three‐component gas mixtures

A solution to the Stefan-Maxwell diffusion equations for equimolal countercurrent diffusion in a three-component gas mixture is obtained which is similar in form to Gilliland's equation for diffusion of two gases through a third inert gas. The important features of both types of diffusion are investigated and the conditions under which the following phenomena occur are determined: (1) diffusion barrier (the rate of diffusion of a component is zero even though its concentration gradient is not zero); (2) osmotic diffusion (the rate of diffusion of a component is not zero even though its concentration gradient is zero); (3) reverse diffusion (a component diffuses against the gradient of its concentration). A generalized driving force which describes these phenomena is introduced, and approximate equations are developed which give the individual rates of diffusion directly.
REARRANGEMENT OF DIMETHYLCARBENE TO PROPENE : STUDY BY LASER FLASH PHOTOLYSIS AND AB INITIO MOLECULAR ORBITAL THEORY

Laser flash photolysis (Nd:YAG laser, 355 nm, 35 mJ, 150 ps) of dimethyldiazirine and dimethyldiazirine-d6 produces dimethylcarbene (DMC) and dimethylcarbene-d6 (DMC-d6), respectively. The carbenes were trapped with pyridine to form ylides which absorb around 364 nm. It was possible to resolve the growth of the ylides as a function of pyridine concentration in Freon-113, α,α,α-trifluoromethylbenzene, and perfluorohexane as a function of temperature. The observed rate constant (kobs) of ylide formation was linearly dependent on the concentration of pyridine in all solvents and at all temperatures. From plots of kobs versus [pyridine] it was possible to extract values of kpyr (the absolute rate constant of reaction of the carbene with pyridine) and τ, the carbene lifetime in the absence of pyridine, and their associated Arrhenius parameters. In Freon-113 and α,α,α-trifluoromethylbenzene the carbenes decay both by rearrangement and by reaction with solvent. In perfluorohexane the carbene decay appears to be .
Near-infrared optical imager for cerebral blood flow and oxygenation detection

This paper describes the theory and the apparatus on our newly developed 64 channel optical imager that enables imaging of three components, indocyanine green (ICG), oxyHb and deoxyHb. Knowledge on blood flow is obtainable using ICG as a blood flow indicator that is to be introduced via injection. ICG has a strong absorption at 805nm, therefore the changes in ICG is detectable with NIR spectroscopy separating from oxyHb and deoxyHb using proper three wavelengths. In addition to the system description, it describes an animal experiment and a phantom test for the validation study. It discusses independence features of ICG on Hb values. Using a simple quasi Lambert Beer's law, it proved the excellent separation of the three components. It also discusses the factors that affect the performance of signal separation.