Miracle-dz/UniFAR-FTUs huggingface dataset:
Preferential Oxidation of CO in H2 Stream on Au/TiO2 Catalysts: Effect of Preparation Method

A series of Au/TiO2 catalysts were prepared by either photodeposition or deposition−precipitation methods. The catalysts were characterized by inductively coupled plasma-mass spectrometry (ICP-MS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The catalytic performance of these catalysts was investigated by preferential oxidation of carbon monoxide in a hydrogen stream. A high gold dispersion and narrow size distribution was obtained for Au/TiO2 catalysts prepared by both photodeposition or deposition−precipitation methods. The photodeposition method facilitates the preparation of gold particles as small as 1.5 nm on the support, whereas in the deposition−precipitation method, the gold particles were found to be around 2−3 nm. The catalyst prepared by the photodeposition method showed higher CO conversion and CO selectivity than those prepared by the deposition−precipitation method. The selectivity of CO reacting with O2 decreased with increas.
Termination Rate Coefficients for Radical Homopolymerization of Methyl Methacrylate and Styrene at Low Conversion

A comprehensive and systematic study of overall termination rate coefficients, k t , in low-conversion radical (homo)polymerization of methyl methacrylate and styrene is presented. Values of k t were determined by gravimetric analysis of steady-state experiments, employing 2,2'-azoisobutyronitrile as initiator. The values delivered by this simple method were found to be in qualitative and quantitative agreement with those from more modern and sophisticated techniques for measuring k t . Accordingly, correlations for bulk, low-conversion k t as a function of temperature are given for each monomer. The effects of initiator concentration, c I , and temperature on bulk k t were studied in a controlled way for both monomers. Additionally, ethyl benzene was used as solvent in order to investigate rigorously the effect of monomer concentration, c M , on styrene k t . The trends found by these systematic studies were considered in the light of what is known about the chain-length dependence of termination. Styrene's behavior was always found to be qualitatively in accord with expectation, although the variations of k t with c I and c M were not as strong as should be the case. However its activation energy, 15 kJ · mol- 1 , is shown to be almost perfectly in agreement with theory. Methyl methacrylate, on the other hand, is recalcitrant in that its overall k t does not make manifest the chain-length dependent termination that has been directly measured by other techniques. Possible reasons for these discrepancies are discussed, as are reasons for the difference in values between k t for the two monomers. On the latter topic it is concluded likely that the chain-length dependence of termination at short chain lengths is primarily responsible for styrene having k t that is higher by a factor of about 3, with there also being a contribution that arises from styrene's slower propagation.
Determination of Antimony in Urine by Graphite Furnace Atomic Absorption Spectrometry after Ion Exchange Separation and Solvent Extraction

Trace antimony in urine was determined by atomic absorption spectrometry using a graphite furnace atomizer. The urine was concentrated and digested with HNO_3-HCIO_4-H_2SO_4 in a Teflon beaker. The bulk of the salts and interfering elements was removed by cation exchange and the ammonium pyrrolidinedithiocarbamate-2-methyl-4-pentanone extraction procedure, and finally the organic phase was analyzed by graphite furnace atomic absorption spectrometry. Results of Sb in the NBS reference material agreed with its certified value. Relative standard deviation were about 8.4% at the 1 -μg level. Antimony contents in urine ranged from 0.3 to 1.3 μg l^-1.
Iron octaethyltetraazaporphyrins: synthesis, characterization, coordination chemistry, and comparisons to related iron porphyrins and phthalocyanines

This paper describes the synthesis and characterization of a series of iron octaethyltetraazaporphyrin complexes and a comparison of these substances to related iron porphyrins and phthalocyanines. Experimental evidence provided by magnetic susceptibility measurements, 1 H NMR, EPR, and Mossbauer spectroscopies, cyclic voltammetry, and/or X-ray crystallography indicates the tetraazaporphyrin ligand is a stronger a donor and π acceptor than is a porphyrin ligand
Studies of Poly-β-benzyl-L-aspartate Helix. III. Infrared Spectra of Copolymers of β-Benzyl-L-aspartate with β-p-Methyl, Chloro, Cyano, or Nitrobenzyl-L-aspartate in a Chloroform Solution

Infrared studies of the copolymers in a chloroform solution have revealed that, in each series of copolymers, the transition from the left- to the right-handed α-helix simultaneously brings about sharp changes in the characteristic amide frequencies. The frequencies of the NH-stretching, amide I, and amide II bands of the copolymers in the left-handed α-helix are higher by ca. 13 cm−1, ca. 10 cm−1, and ca. 5 cm−1 respectively than those in the right-handed α-helix. The amide bands of the copolymers in the right-handed form lie in the normal frequency ranges as established for α-helical polypeptides. On the contrary, the amide frequencies of poly-β-benzyl-L-aspartate or the copolymers in the left-handed form are anomalous. The anomalous amide frequencies of the lefthanded helix are to be ascribed to the reversal in the helical sense, but not to the particular aspartate group, since the copolyaspartate esters in the right-handed helix exhibit normal amide frequencies. The transition in the helical sense is .
Surface Layer Composition Change under Irreversible Conditions of Particle Beam Action

The simple isothermal problem is formulated to describe the composition of surface layer change during particle beam action. The finiteness of relaxation time for mass flux is taken into account. The analytical solutions for some limiting cases are presented. Numerical solution of total problem is carried out. It is shown that concentration distributions for reactants and for reaction product depend on relation between various physical scales.
N,N-Dimethyl­acetamide complex of aluminium(III) perchlorate

In the title compound, bis­[hexa­kis(N,N-dimethyl­acet­am­ide)aluminium(III)] bis­(N,N-dimethyl­acetamide)ium hepta­kis(perchlorate), [H(C4H9NO)2][Al(C4H9NO)6]2(ClO4)7, the AlIII ion has an octa­hedral coordination environment. The singly charged cation lies on a centre of inversion. One of the anions lies on an inversion centre and is disordered; a second anion is also disordered. Three Al—O—C—N torsion angles deviate significantly from 180°, indicating that the Al—O bonds are displaced from the direction of the lone pair of the sp2 O atom. This is ascribed to the steric hindrance of the ligand in an octa­hedral environment.
Changes in the Surface Chemistry and Adsorptive Properties of Active Carbon Previously Oxidised and Heat-Treated at Various Temperatures. I. Physicochemical Properties of the Modified Carbon Surface

Several active carbon samples with different quantities of surface oxides were obtained by annealing previously oxidised material under vacuum at various temperatures (ranging from 180°C to 900°C). Concentrated HNO3 was used as the oxidiser. The oxygen content, the pH of the aqueous slurry and the concentration of surface functional groups were determined for all the carbons. Spectral studies (FT-IR, XPS) were performed for selected samples. The heterogeneous decomposition of hydrogen peroxide was also studied. The catalytic activity for H2O2 decomposition correlated well with the acid consumption on the carbon materials. A linear relationship was derived between the oxygen reduction potentials and the logarithm of the peroxide decomposition rate constants.
Two dimensional anisotropic etching in tracked glass

We describe in this paper the creation of a two-dimensional pore gradient using hydrofluoric acid (HF) chemical etching of tracked glasses (TGs). The first gradient was along the plane of TGs where the pore diameters of the conical pores were modulated, and a second gradient was formed in pores along the axis of each pore. The 2-D pore gradient in TGs was characterized with optical and electron microscopies. We demonstrate that the pore gradient was formed only when the TGs had a thin layer of polydimethylsiloxane (PDMS) on their surface and when the etching solution was not stirred. The 2-D pore gradient was also found to be dependent upon the TG orientation with respect to the etching solution. Following the reaction between HF and PDMS, the resulting insoluble precipitate was deposited, due to gravity, at the bottom of the vertical TG's etching surface, accruing at the mouths of the pores. This precipitate deposition at pore mouths appeared to hinder the diffusion of HF to the pore surface. This build up also caused the retention of the by-products inside the pores which further suppressed the etching of the glass. The etching process was inhibited more at the bottom of the chips than that at the top presumably due to the formation of a precipitate gradient on TG surface. Using a 2-D pore gradient containing TGs, many different experiments can be performed simultaneously which will improve the throughput rate and aid analysis in many potential applications in materials and life sciences.
A facile route to pyrroles, isoindoles and hetero fused analogues

Enamino acids derived from 1,2-dimethylaminomethylene- or 1,2-hydroxymethylene-carbonyl compounds and amino acids undergo a decarboxylative cyclisation to pyrroles, isoindoles and other fused pyrroles. A two atom ring expansion occurs preferentially with enamino acids from cyclohexane-1,3-diones and α-alkyl-α-amino acids leading to oxocino[2,3-c]pyrroles.
Application of liquid chromatography/mass spectrometry to the qualitative analysis of saponins. II.

Qualitative analysis of crude saponin fractions from Panax ginseng, Panax japonicus and Bupleurum falcatum, as well as authentic saponins, was performed with a new type of liquid chromatography/mass spectrometry (LC/MS) system equipped with a frit-fast atom bombardment (FRIT-FAB) interface. The separation of saponins was achieved on a semi-micro column by gradient high performance liquid chromatography using an acetonitrile and water system as a mobile phase, and the elution profile was monitored by fast atom bombardment mass spectrometry (FAB-MS). The peaks were readily identified from their retention times and negative ion FAB spectra. Thus, LC/MS in the gradient-elution mode was demonstrated to be useful for qualitative analysis of saponins in crude drugs.
Evaluation of yield and nutritive value of kenaf (Hibiscus cannabinus) at various stages of maturity.

The objective of this study was to evaluate potential yield and chemical composition of kenaf as fodder for ruminants. Kenaf (Hibiscus cannabinus), variety Khon-Kaen 50, was planted at seed and row spacing of 30 and 50 cm, respectively. The plants were sampled at 6, 8, 10 and 12 weeks after planting. The findings revealed that dry matter yield and crude protein yield of 6-12 week-old kenaf were 0.12-2.14 and 0.02-0.14 t/ha, respectively (p<0.05). Crude protein (14.34-6.58%) content of kenaf decreased significantly (p<0.05) as harvesting age advanced. On the other hand, neutral detergent fiber (41.99-48.74%) and acid detergent fiber (27.20-30.57%) of kenaf increased statistically (p<0.05) with maturity advanced. The results indicated that 10 week-old kenaf with DM yield of 0.95 t/ha and contained 10% of CP could be used as fodder for ruminants.
Properties of TiO2‐based transparent conducting oxides

The development and properties of titanium dioxide (TiO2)‐based transparent conducting oxides (TCO), which exhibit properties comparable to those of In2–xSnxO3 (ITO), are reviewed in this article. An epitaxial thin film of anatase Ti0.94Nb0. 06O2 exhibited a resistivity (ρ) of 2.3 × 10−4 Ω cm and internal transmittance of ∼95% in the visible light region. Furthermore, we prepared polycrystalline films with ρ of 6.4 × 10−4 Ω cm at room temperature on glass substrates by using sputtering. We focus on characteristics unique to TiO2‐based TCO, such as a high refractive index, high transmittance in infrared, and high stability in reducing atmospheres. Possible applications of TiO2‐based TCOs, as well as the mechanism of the transparent conducting properties found in this d‐electron‐based TCO, are discussed in this review.
Volatile Components of Sapodilla Fruit (Manilkara achras L.)

Abstract The volatile components of sapodilla fruit, which were isolated by simultaneous steam distillation/solvent extraction with diethyl ether, were identified by a combination of retention indices and GC/MS. Sixty-nine constituents were identified in the aroma concentrate, from which methanethiol (32.0%), hexadecanoic acid (26.3%), 3-hydroxy-2-butanone (6.8%), ethyl acetate (6.0%) and isoamyl alcohol (5.9%) were found to be the major constituents.
H-D Isotope and Chain-Length Dependence of Phase Separation in Quenched n-Alkane Binary Combinations in the Crystalline State

Certain binary n-alkane combinations, quenched to room temperature from the comelt, form metastable solid solution crystals that subsequently undergo spontaneous demixing. The degree and rate of phase separation are known to depend upon the chain-length difference of the two components. Recently, we have found that, in addition to the chain-length difference, the isotopic composition (H or D) can also be an important factor affecting the separation. We report here electron diffraction and calorimetric measurements, revealing the relative tendencies for microphase separation for the four possible isotopic combinations in C 30 /C 36 (depending on whether each ingredient is perhydrogenated or perdeuterated). The isotope effect on phase stability is shown to be qualitatively similar to that of changing the chain-length difference, if the volume difference between CH 2 and CD 2 methylene groups, respectively, is expressed in terms of chain length. This trend is explored further for binaries C 30 /C n . , where n' is systematically increased. Measurements made in this study are then compared to those from vibrational spectroscopy.
Ionization of C60 by fast bare-ion impact

Angular distributions of the ionization of C60 due to bare ion impact are calculated in the plane-wave Born approximation. The core of C4+ ions in C60 is frozen to a jellium sphere and 240 valence electrons are treated by the Kohn-Sham formalism. Two approximations are employed: one that omits the electron correlation in a static local density frame and another that incorporates the correlation through the linear time-dependence. Strong effects of the correlation on the dipole as well as the non-dipole contributions to the angular distribution are found.
Molecular theory for mixed micelles

A molecular theory for the formation of mixed micelles is developed here as an extension of our earlier theory for single-component micelles. The theory permits the calcuiation of the cmc, the average micelle size, and the average micelle composition as well as the size and the composition distribution of micelles in mixed surfactant systems. Central to the theory is an explicit molecular thermodynamic expression for the Gibbs energy of formation of the mixed micelle. This Gibbs energy of micelle formation, which is composition dependent, can be decomposed into bulk and interfacial components. The bulk component includes the free energy contributions arising from the transfer of the surfactant tail from water to th'e micelle. The interfacial component includes the free energy contributions due to the micellar core-water interfacial energy, the steric repulsions between the head groups at the micelle surface, and the electrostatic repulsions between the head groups at the micelle surface. If the Gibbs energy of micelle formation is a linear function of the micelle composition, then the excess Gibbs energy is zero and the surfactant mixture behaves ideally. On the other hand, if the Gibbs energy of micelle formation has a nonlinear dependence on the micelle composition, then the excess Gibbs energy is nonzero and the surfactant mixture displays nonideal micellization behavior. It is shown that the bulk component of the Gibbs energy of micelle formation depends linearly on the micelle composition and hence does not account for any nonideal behavior displayed by the mixed micelles. In contrast, the interfacial component has a nonlinear dependence on the composition of the mixed micelle and thus constitutes the source of the observed nonidealities in mixed micellar systems. Therefore, surfactant mixtures displaying markedly nonideal micellization behavior are those for which the interfacial interactions show significant composition dependence. Illustrative results based on this molecular theory are obtained for a number of binary mixtures and are compared against the available experimental data.
Polyaniline nanotubes with rectangular-hollow-core and its self-assembled surface decoration: high conductivity and dielectric properties

Polyaniline (PANI) nanotubes with a rectangular hollow core and decorated outer surface-wall with self-assembled nanobeads and triangular flakes of PANI have been synthesized in the presence of ZnO NPs by a sonochemical approach. This is the first example of the formation of well-defined hollow PANI nanotubes with a rectangular hollow interior. The hollow PANI nanotubes have an average length of ca. 10 μm and a hollow core with rectangular geometry. Nanobeads of PANI with diameter ca. 50 nm have been decorated/self-assembled on the surface of the outer wall of rectangular hollow PANI nanotubes to obtain a “Date-tree-like” 3D structure. The crystal structure has been characterized through XRD. The conduction bands and electronic environment have been confirmed through Raman, FT-IR, UV-Vis-NIR, XPS and EPR. Impedance measurements of rectangular hollow PANI nanotubes demonstrate their higher electrical conductivity (σ = 1.1 ± 0.1 × 10−4 S m−1 to 3.0 ± 0.23 × 10−3 S m−1) and dielectric properties, depending on the frequency range compared to the PANI particles synthesized in the presence of H+ and solid PANI fibres. PANI nanotubes with this novel rectangular hollow core structure and surface decorated texture are a unique type of nanostructure, which can be used in various conductive polymer based device applications.
The asymptotic asymmetric-top rotational partition function

The high-temperature asymptotic expansion of the rotational partition function of a rigid asymmetric-top molecule can be written in the form where g is the mean nuclear statistical weight and g ζ is a nuclear statistical weight factor associated with the principal axis ζ. The asymptotic expansion of Q′, which is calculated by two different methods, is expressed in the formulation of McDowell as where Here, α, β and γ are the dimensionless temperature-reduced rotational constants hcA/kT, hcB/kT and hcC/kT, and each sum is over the three cyclic permutations of (α, β, γ). For the Q′ζ, the principal asymptotic approximations are obtained, confirming results in the 1955 dissertation of Woolley.
Surface modification of polypropylene by radiation grafting of hydrophilic monomers: Physicochemical properties

The surface of polypropylene was modified by the post-irradiation grafting of acrylic acid (AAc), N,N-dimethylacrylamide (DMA) and mixtures of AAc (DMA) and a quaternary ammonium salt (QAS). The polypropylene sheets were activated by electron beam radiation before the grafting reaction. The degree of grafting was determined by weighing and the surface hydrophilicity was measured by measuring the water contact angles. The presence of oxygen and nitrogen was demonstrated by XPS. The surface charge and the isoelectric point were determined by the streaming potential method. The grafting of DMA, like that of AAc, depended on monomer availability, but the monomer did not permeate into the polypropylene bulk. For the same surface hydrophilicity, depending on the nature of the monomer or comonomer grafted, it is possible to modulate the physicochemical characteristics which determine the phenomena governing adhesion, and probably to adapt them to a given application.
The Janus-like behaviour of sulfur in substituted diquinoline inclusion crystal structures

The crystal structures of the methylene-bridged diquinolines 1,2 are compared to those of their newly synthesised thia-substituted analogues 9,10. As expected from our molecular design, neither non-brominated compound 1 nor 9 shows inclusion properties, but the dibrominated structures 2 and 10 act as versatile lattice inclusion host molecules. All our crystal structures of the methylene-bridged compounds 1,2 contain an (EF)6 centrosymmetric dimeric building block, built from three different types of aryl edge-face (EF) interactions. The crystal structures of the thia-compounds 9,10 also involve (EF)6 dimers, but fall into two distinct types. In one group, the sulfur atom effectively mimics the methylene group and isostructural compounds result across the two series. The second group is comprised of structures that are markedly dissimilar between the two series, even though the sulfur substituent does not play an overt role in the molecular packing. These similarities and differences are examined in crystal engineering terms.
Measurements of Water Solubilities and 1-Octanol/Water Partition Coefficients and Estimations of Henry's Law Constants for Brominated Benzenes

The water solubilities (Sw) at various temperatures from 283 K to 308 K and 1-octanol/water partition coefficients (Kow) for four brominated benzenes (1,4-dibromobenzene, 1,2,4-tribromobenzene, 1,2,4,5-tetrabromobenzene, and hexabromobenzene) were measured by either the generator-column or the shake-flask method and the high-performance liquid chromatography method, respectively. These solubility data revealed not only the temperature dependence of Sw, in the form of the enthalpy of solution (ΔsolH), but also the effect of bromine substitution on Sw and ΔsolH. To estimate the activity coefficients (γw) of the brominated benzenes in water from the present Sw data, enthalpies of fusion and melting points for those compounds were measured with a differential scanning calorimeter. Henry's Law constants (Hw) of the brominated benzenes were derived assuming that the obtained γw represented the infinite dilution activity coefficients (γw∞). Some physicochemical characteristics of brominated benzenes were also su.
Drastic change of the electrical resistivity related to the novel magnetic phase transition in α-Sm2S3

Magnetization and electrical resistivity of α-Sm2S3 have been investigated by using single crystals. The temperature dependence of the magnetization; M(T), demonstrates a magnetic transition at around T = 4.5 K. The M(T) shows abrupt rise below 5K with decreasing temperature in the low magnetic filed of H = 100 Oe. Zero-field-cooled M(T) shows a sudden decrease with marking a maximum at 4.5 K, while field-cooled M(T) keeps steady rising around this temperature. The magnetization M(H) in the magnetic field along the c-axis shows a ferromagnetic hysteresis at the lower temperature than TC = 4.5 K, although its magnitude is much smaller than the value for the full Sm3+ moment. The resistivity ρ(T) indicates a double peak having the maxima at T = 4.65 and 3.3 K in no magnetic field. The ratio of ρ(4.65 K) to ρ(6.0 K) is extremely large as it exceeds 100. The double peak diminishes rapidly with increasing magnetic field. The negative giant magneto-resistance effect having the magneto-resistance ratio of −99 % at H = 10 kOe has been observed at T = 4.5 K.