Miracle-dz/UniFAR-FTUs huggingface dataset:
Methane Oxyforming for Synthesis Gas Production

This article is concerned with the reforming of methane to synthesis gas; a review of the steam reforming Rxn is presented, and the dry reforming and partial oxidation Rxns introduced. Collectively, these processes are known as “oxyforming. ” A background to oxyforming, industrial practice, and some of the most important latest developments will be presented, along with a section on the uses of synthesis gas. The current understanding of the Rxn mechanisms for the three processes and the problem of deactivation by carbon deposition will be discussed in detail. Finally, the economics of synfuel production will be addressed and compared with the production of other fuels, and the future directions and outlook for oxyforming will be forwarded. This article should allow the reader to make comparisons between these three important industrial reactions.
Synthesis of Highly Monodisperse Citrate-Stabilized Silver Nanoparticles of up to 200 nm: Kinetic Control and Catalytic Properties

Highly monodisperse sodium citrate-coated spherical silver nanoparticles (Ag NPs) with controlled sizes ranging from 10 to 200 nm have been synthesized by following a kinetically controlled seeded-growth approach via the reduction of silver nitrate by the combination of two chemical reducing agents: sodium citrate and tannic acid. The use of traces of tannic acid is fundamental in the synthesis of silver seeds, with an unprecedented (nanometric resolution) narrow size distribution that becomes even narrower, by size focusing, during the growth process. The homogeneous growth of Ag seeds is kinetically controlled by adjusting reaction parameters: concentrations of reducing agents, temperature, silver precursor to seed ratio, and pH. This method produces long-term stable aqueous colloidal dispersions of Ag NPs with narrow size distributions, relatively high concentrations (up to 6 × 1012 NPs/mL), and, more important, readily accessible surfaces. This was proved by studying the catalytic properties of as-syn.
Radical Scavenging Activities of Plant Food of Alkyl-oxy and Superoxide Radicals

The spin trapping ability against alkyl-oxy and superoxide radicals was examined using a new reagent 5-(2,2-dimethy-1,3-propoxycyclophosphoryl)-5-methyl-1-pyrroline N-oxide (CYPMPO), a colorless crystalline that is very soluble in aqueous solution. For careful detection of spin adducts, we used borosilicate ESR flat cells. We examined plant specimens from teas, vegetables and fruits. CYPMPO successfully trapped alkyl-oxy and superoxide radicals in the plant extracts. We generated very pure alkyl-oxy radicals by illuminating phosphate buffer solution containing 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and CYPMPO with Hg-Xe arc lamp. Superoxide radicals were similarly generated using hypoxanthine (HPX), diethylene-triamine-pentaacetic acid (DTPA), CYPMPO and xanthenes oxidase (XOD). The spin adducts by CYPMPO were sensitive and very stable. The trapping activity for the alkyl-oxy and superoxide radicals was measured by the 2-amino-5-{[2-[(carboxymethyl)amino]-1-(mercaptomethyl)-2-oxoethyl]amino} 5-oxopentanoic acid (GSH) and superoxide dismutase (SOD) equivalents, respectively. Thus, CYPMPO is useful for its high capability of radical trapping.
Chemical reactions in liquid induced by atmospheric-pressure dc glow discharge in contact with liquid

We experimentally investigated some of the initial reactions in a liquid induced by electron or positive-ion irradiation from an atmospheric-pressure dc glow discharge in contact with the liquid. Aqueous solutions of NaCl, AgNO3, and HAuCl4 are used as the electrolyte. We measured the pH and conductivity in the liquid at approximately 1 cm below the solution surfaces. OH radical generation in the liquid was observed by a chemical probe method. Experimental results showed that electron irradiation of the liquid surface generates OH− in water and that positive-ion irradiation of the liquid surface generates H+ in water even without the dissolution of gas-phase nitrogen oxide. A possible reaction process is qualitatively discussed. In particular, the contribution of charge transfer collision between impinging low-energy positive ions and water molecules to the ionic species in the liquid is used to explain the overall tendency of the experimental results.
Biocorrosion Behavior of Titanium Oxide/Butoxide-Coated Stainless Steel

Stainless steel coated with multilayers of Ti oxide/butoxide was prepared via a layer-by-layer sol-gel deposition process. The successful buildup of the Ti oxide/butoxide coatings was ascertained by X-ray photoelectron spectroscopy and static water contact angle measurements. The differences in corrosion behavior between the Ti oxide/butoxide-coated and the uncoated coupons in a simulated seawater-based modified Baar's medium inoculated with Desulfovibrio desulfuricans under anaerobic conditions were investigated by electrochemical analyses, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). Electrochemical analyses and SEM results revealed that the pristine, the hydroxylated, and the nitric acid-passivated coupons were all vulnerable to biocorrosion due to localized breakdown of the passive film under synergistic attack of Desulfovibrio desulfuricans and biogenic sulfide ions, leading to destructive pitting and crevice corrosion. However, the Ti oxide/butoxide-coated coupons exhibited desirable resistance in the biocorrosion environment and the coating remained relatively stable throughout the exposure period. EDX analysis revealed that the bioactive properties of the Ti oxide/butoxide coating arose from the concomitant deposition of calcium and phosphorous compounds. The increase in resistance of the Ti oxide/butoxide coatings with time was correlated with the increase in nucleation of calcium apatite in electrochemical studies.
Raman Spectrum of Graphite

Raman spectra are reported from single crystals of graphite and other graphite materials. Single crystals of graphite show one single line at 1575 cm−1. For the other materials like stress‐annealed pyrolitic graphite, commercial graphites, activated charcoal, lampblack, and vitreous carbon another line is detected at 1355 cm−1. The Raman intensity of this band is inversely proportional to the crystallite size and is caused by a breakdown of the k‐selection rule. The intensity of this band allows an estimate of the crystallite size in the surface layer of any carbon sample. Two in‐plane force constants are calculated from the frequencies.
Advances in Crystallization Elution Fractionation

Crystallization Elution Fractionation has been optimized to improve resolution power and reduce co-crystallization. Most important step to be optimized is the first separation cycle of Dynamic Crystallization which can be investigated with the help of Crystallization Analysis Fractionation experiments. A new approach to reduce co-crystallization and improve resolution is presented by applying successive cooling and heating cycles in a long column. The new process known as Multiple Crystallization Elution Fractionation adds extended separation at each cooling and heating cycles.
Direct Compositional Analysis of Ordered Domains in Pure and La‐Doped Pb(Mg1/3Nb2/3)O3 by Analytical Electron Microscopy Techniques

The ordered domain structures in Pb(Mg 1/3 Nb 2/3 )O 3 (PMN) and Pb 1-x La x (Mg 1/3 Nb 2/3 )O 3 are identified using high-resolution transmission electron microscopy (HRTEM) and nanobeam diffractometry (NBD). The chemical compositions in the ordered domains and in the disordered matrices are also acquired using energy-dispersive spectroscopy (EDS). The best matching computer-simulated HRTEM image has a Mg 2+ / Nb 2+ ratio of 1/2. There is no obvious chemical composition difference between the ordered domains and the disordered matrices. The number of the normalized total positive valence electrons remains almost constant in the ordered domains and in the disordered matrices for all the samples. The reason for the growth of the ordered domains in La-doped PMN also is discussed.
Equilibrium speciation in moderately concentrated formaldehyde−methanol−water solutions investigated using 13C and 1H nuclear magnetic resonance spectroscopy

We used 13C and 1H NMR spectroscopy to examine the equilibrium speciation in formaldehyde–methanol–water solutions at moderate formaldehyde concentrations such as those used in the synthesis of formaldehyde-based organic gels. Concentrations of small methylene glycol oligomers and their methoxylated forms found in these solutions were quantitatively determined over a range of formaldehyde concentrations and methanol–water ratios, and at temperatures between 10 and 55 °C. Using the measured concentrations, equilibrium constants for methylene glycol dimer and trimer formation as well as methoxylation of these oligomers were calculated. Based on this, we developed a quantitative equilibrium model for calculation of formaldehyde-related species concentrations over a range compositions relevant for formaldehyde based sol–gel processes allowing for more rational design of formaldehyde polymerization systems.
Minireview: A Comeback of Hg‐Derivatives in Protein Crystallography with Cys‐Modification

While a majority of protein crystal structures are solved by using molecular replacement (MR), it is limited by the available homologous models with sufficient sequence identity. Another popular method is multi-wavelength anomalous diffraction (MAD) that uses Se-Met and synchrotron radiations. However, proteins containing Se-Met are sometimes difficult to obtain and/or crystallize. Consequently, other heavy-atom derivatives are still used in crystal structure determination, while single isomorphous replacement (SIR) and single wavelength anomalous diffraction (SAD) are more popular than conventional multiple isomorphous replacement (MIR). Here, some recent cases of structure determination in which Hg serves as the only heavy-atom type are discussed. For Hg-derivatives, data collection does not need absorption spectrum scanning and it can be carried out using an in-house X-ray source. Derivatization with Hg can start directly by soaking the native crystals in Hg-containing solutions, or use a specific mutant in the active site of an enzyme if it lacks intrinsic free cysteine residues. The rapid advance of bioinformatics and protein engineering has made this strategy of cysteine-dependent Hg-phasing by MIR, SIR and SAD an effective method of choice besides MR and MAD for crystal structure determination.
Characterization and discrimination of saffron by multisensory systems, SPME-GC-MS and UV-Vis spectrophotometry

Different electronic sensor systems coupled with multivariate data analysis were applied to characterize and classify seven saffron samples and to verify their declared geographical origin. The proposed electronic sensing consists of a low-cost electronic nose (E-nose) based on metal oxide semiconductor sensors and a voltammetric electronic tongue (VE-tongue) based on voltammetric sensors. The ability of multivariable analysis methods such as Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA) and Support Vector Machines (SVMs) to classify the saffron samples according to their geographical origin have been investigated. Both PCA and HCA have shown an overlapping of E-nose responses. Moreover, the SVM analysis of the E-nose database reached a 66.07% success rate in the recognition of the saffron sample odour. On the other hand, good discrimination has been reached using PCA and HCA in the VE-tongue characterization case, besides a 100% accuracy in the saffron flavour recognition was attained. To validate the proposed electronic sensing systems, analytical chemical methods such as SPME-GC-MS and UV-Vis spectrophotometry were used. These analytical methods could be helpful tools to identify the composition of volatile compounds of the analysed saffron samples. Moreover, UV-Vis spectrophotometry was also used to determine the non-volatile profile of the samples from different geographic origins. It is demonstrated that the electronic sensing systems' findings are in a satisfactory correlation with the analytical methods. In the light of these results, we might say that the electronic systems offer a fast, simple and efficient tool to recognize the declared geographical origin of the saffron samples.
Betti Reaction of Cyclic Imines with Naphthols and Phenols – Preparation of New Derivatives of Betti's Bases

A large library of aminocycloalkylphenols and -naphthols is obtained by the Betti reaction between activated phenols and naphthols and five- and six-membered cyclic imines. Due to the formation of an intramolecular hydrogen bond in the transition state, the attack takes place regioselectively at the position adjacent to the hydroxy group of the aromatic compounds. X-ray crystallography and chirooptical methods (electronic circular dichroism) were used to ascertain the absolute configuration of two aminoalkylnaphthols obtained, after resolution of the corresponding racemates with (R,R)-tartaric acid. In addition, some aminoalkylnaphthols and-phenols were alkylated at the nitrogen atom to obtain N-methylated products in good yields.
Polymer electrolyte membranes based on sulfonated polysulfone and functionalized layered silicate for direct methanol fuel cell applications

Polymer electrolyte membranes (PEMs) of sulfonated polysulfone (SPSf) and sulfonated montmorillonite (SMMT) have been developed. Sodium montmorillonite (NaMMT) has been sulfonated with 4-sulfophthalic acid and incorporated into the SPSf matrix for further enhancement of proton conductivity. Sulfonation of NaMMT has been confirmed using Fourier transform infrared spectroscopy and X-ray diffraction (XRD) analysis. The XRD patterns proved that the SMMT layers were completely exfoliated within the SPSf matrix. The performances of the PEM in terms of their liquid uptake, oxidative stability, and proton conductivity were investigated. The morphological characterizations have been carried out using scanning electron microscopy and atomic force microscopy. SPSf/SMMT membrane with 5 wt% of SMMT loading showed adequate thermal stability and an improved proton conductivity. The reduction in methanol permeability from 8.9 ×10−5 cm2 s−1 to 2.4 × 10−5 cm2 s−1 has been observed when SMMT loading content increased from 1 wt% to 5 wt%. Direct methanol fuel cell (DMFC) performance showed a power density value of 49 mW cm−2for SPSf/SMMT membrane, indicating its candidature for DMFC applications.
Self-patterning of arrays of ferroelectric capacitors: description by theory of substrate mediated strain interactions

Self-patterning presents an appealing alternative to lithography for the production of arrays of nanoscale ferroelectric capacitors for use in high density non-volatile memory devices. However current levels of registration achieved experimentally are far from adequate for this application. To provide a guide for experiment we have applied the theories developed for self-patterning of semiconductor nanocrystals to two self-patterning systems of potential interest for ferroelectric memory applications, metallic bismuth oxide on bismuth titanate and ferroelectric lead zirconate titanate on strontium titanate.
Photo-Cross-Linkable PNIPAAm Copolymers. 5. Mechanical Properties of Hydrogel Layers

Atomic force microscopy (AFM) was used to study the mechanical properties of photo-cross-linked, temperature-responsive hydrogel layers in water. Photo-cross-linkable linear polymers based on N-isopropylacrylamide and 2-(dimethylmaleimido)-N-ethyl-acrylamide were spin-coated to produce uniform thin films of cross-linked responsive hydrogels. These films were imaged using AFM, and force−distance curves were used to measure the temperature-dependent elastic modulus. The volume phase transition of the hydrogel layers is constrained by the presence of a fixed substrate, and the length scale of these effects is related to the modulus. These materials were also studied with surface plasmon resonance and optical waveguide spectroscopy to determine the polymer volume fraction as a function of the temperature. The modulus varies as a function of the polymer volume fraction and is in good agreement with previous measurements on bulk hydrogels. The effect of the cross-linking density and degree of ionization on the .
Electronic spectra of jet-cooled tropolone. Effect of the vibrational excitation on the proton tunneling dynamics

The laser fluorescence excitation spectra and single vibronic level fluorescence spectra have been measured for jet‐cooled tropolone (–OH) and tropolone (–OD). The ν’11(a1), ν12(a1), and ν’19(a2), modes have been newly identified in the excitation spectrum of tropolone (–OH), in addition to the previously observed ν13(a1), ν’14(a1), ν25(b1), and ν’26(b1) modes. The tunneling doublet splittings of these modes in the A 1B2 state have been determined to investigate the effect of the vibrational excitation on the proton tunneling dynamics. The tunneling splitting is highly mode specific. The ν13(a1) and ν’14(a1) skeletal deformation modes are strongly coupled to the proton transfer coordinate and enhance tunneling, whereas the ν19(a2) skeletal twisting mode as well as ν’25(b1) and ν26(b1) out‐of‐plane bending modes diminish tunneling. The ν’11(a1) C–C stretching and ν12(a1) C–C–C bending modes are considered to be weakly coupled to the proton transfer coordinate, because the tunneling splittings of these mod.
A comparative study of defect states in evaporated and selenized CIGS(S) solar cells

Current‐voltage, admittance spectroscopy, and drive‐level capacitance profiling measurements were taken on Cu(In1−xGax)(Se1−ySy)2 solar cell devices. The devices were made using two different types of absorbers. One set of absorbers was deposited via physical vapor deposition, while the other set of absorbers was made by selenization of metal precursors. Additionally, each type of absorber was completed with one of two different types of buffer treatments: a CdS layer or a cadmium partial electrolyte surface modification. The devices with the evaporated absorbers had larger values of VOC, higher carrier densities, lower densities of trapping defects, and likely shallower gap states. Results were qualitatively similar for the CdS and partial electrolyte buffers. Copyright © 2005 John Wiley & Sons, Ltd.
Optimization of extinction efficiency of gold‐coated polystyrene bead substrates improves surface‐enhanced Raman scattering effects by post‐growth microwave heating treatment

We report a novel post-growth microwave treatment approach to selectively modify the surface morphologies of gold (Au) films coated on the polystyrene (PS) bead substrates for effectively improving the surface-enhanced Raman scattering (SERS) effect on the analytes. The discrete dipole approximation (DDA) model was introduced to evaluate the enhancement effects by calculating the localized electromagnetic field distribution and extinction efficiency based on the sizes of the trenches and voids, and the surface roughness of the modified Au–PS bead substrates. The SERS performance of microwave-modified Au–PS substrates on rhodamine 6G (Rh 6G) and saliva yields at least 10-fold improvements in SERS intensities compared to the as-grown substrates, which is also in agreement with theoretical predictions by DDA modeling. This work demonstrates both experimentally and theoretically the efficacy of the microwave heating treatment on modifying the Au–PS bead substrates for the realization of high SERS performance in biomedical applications. Copyright © 2009 John Wiley & Sons, Ltd.
Identification of Transfer Functions in Feedback System and Inverse Problem

A unified theory of identification in a feedback system is presented from the viewpoint of inverse problem on reactor noise. A power reactor described by a 4 block feedback model is expressed in terms of equivalent correlation functions as a 5 block feedback model with an additional loop, if one of subsystems of the reactor becomes unstable, however, the total system is stable by negative feedback effects, and if noise sources are not independent. The addition of a loop in the feedback system leads errors in estimation of open loop transfer functions. In the case, modified open loop transfer functions are identified instead of original ones. From the viewpoint of reactor diagnosis, notes on system identification are discussed on an open loop transfer function in a low power reactor and on effects of diagonalization in covariance space of noise sources.
A Comparative Study of Methanol to Olefin over CHA and MTF Zeolites

H-SSZ-13 (CHA) and H-UTM-1 (MTF) zeolites have been synthesized, characterized, and employed as catalysts for the methanol-to-olefin (MTO) reaction. Both zeolites have eight-membered rings, and their structures and acidities are characterized by 27Al magic-angle spinning (MAS) NMR, NH3−TPD (temperature-programmed desorption), and in-situ IR spectroscopy. In-situ IR spectroscopy indicates that methanol is efficiently activated on the Bronsted acid sites of both zeolites. At 673 K, the methanol is quantitatively converted to hydrocarbons, mainly ethene and propene, over H-SSZ-13, whereas H-UTM-1 only initially gives a small amount of alkenes, the main product being dimethyl ether. It is proposed that the limited space in the cages of the MTF zeolite prevents formation of intermediate polymethylbenzenes and thereby also formation of hydrocarbons, whereas the cage size in the CHA type zeolite, which is active, is large enough to accommodate polymethylbenzenes.
Enantioselective Synthesis of Non-Natural Aromatic α-Amino Acids

We present two complementary methods for the stereoselective synthesis of non-natural alpha-amino acids with aromatic or heteroaromatic side chains. One approach is based on the chemical transformation of methionine, whereas the other applies the stereoselective Myers alkylation of glycine. The resulting product types differ in the linker length between glycine and the aromatic substituent. Since methionine and pseudoephedrine are available in both absolute configurations, R- or S-configured enantiopure amino acids with either C(2) or C(3) linkers can be obtained on gram scales. In each case the key step of the synthesis is hydroboration of the unsaturated building blocks 9 and 17, followed by palladium-catalyzed Suzuki cross-coupling with aryl halides. Attention must in certain cases be paid to the stereochemical integrity when basic Suzuki conditions are applied. Our initial difficulties are reported as well as the final "racemization-proof" procedures. The protecting groups chosen for the alpha-amino acids should be compatible with solid-phase peptide synthesis. This was confirmed by the successful synthesis of a series of tripeptides.
Thermodynamics and Molecular Dynamic Simulations of Three-phase Equilibrium in Argon (V6)

SUMMARY Very simplified equations of state (EOS) are proposed for a system involving argon and consisting of a perfect solid and a perfect liquid composed of single spherical molecules in which Lennard –Jones interactions are assumed. Molecular dynamics simulations of this system w ere performed to determine the temperature and density dependencies of the internal energy and pressure and the supercooled liquid state was also examined. The internal energy and pressure were found to be almost linear as functions of temperature at a fix ed volume. The density dependencies of coefficients for pressure and the internal energy are written by linear functions of number density for simplicity and for ease of use.