Miracle-dz/UniFAR-FTUs huggingface dataset:
Formation of Germanium Nitride Nanowires on the Surface of Crystalline Germanium

We report on the growth mechanisms of germanium nitride nanowires on the surface of crystalline Ge annealed in hydrazine vapor at different temperatures. In spite of the presence of water (and hence oxygen precursors) in hydrazine, the pure germanium nitride single crystal nanowires were produced in the temperature range of 480–C. At temperatures below C, the clusters were formed first at the Ge surface, followed by the nucleation and growth of nanowires through the Vapor-Liquid-Solid mechanism. The Vapor-Solid growth mechanism was observed at temperatures exceeding C, and Ge3N4 nanobelts were produced instead of nanowires with circular cross-sections. All nanostructures have the alpha germanium nitride structure; however, at the nucleation stage, the presence of beta Ge3N4 phase was also observed in the roots of nanowires.
An in situ Raman spectroscopic study of Na2Si2O5 at high pressures and temperatures: Structures of compressed liquids and glasses

Abstract Raman spectra of Na2Si2O5 glass and Na2Si2O5 liquid have been collected in situ to pressures of 16 GPa at 300 K and 10 GPa at 885 K. In glass compressed at 300 K, bands associated with intertetrahedral bridging 0 atoms decrease in intensity and ultimately become unresolvable above 8 GPa. Over this same pressure range, new peaks appear in the glass between 600 and 800 cm-1; these new features are consistent with the formation of SiO5 or SiO6 polyhedra through the destruction of nonbridging O atoms. Between ∼10 and 16 GPa, band intensities shift, the total integrated Raman scattering intensity of the glass decreases by more than a factor of ten, and the pressure dependence of mode shifts changes. These changes are consistent with a new densification mechanism initiated in the glass above ∼ GPa, probably from the formation of linkages between two or more highly coordinated Si atoms. No vibrations attributed to bridged silica tetrahedra are observed in the liquid above 8 GPa, indicating that at least 50% of the Si in the liquid at 8 GPa is highly coordinated. Upon decompression of thermally quenched samples at 300 K, bands associated with bridged tetrahedra reappear at pressures below 1 GPa. Similarly, glasses that have been compressed only at 300 K and then decompressed have bands associated with bridged tetrahedra. The formation of bands associated with bridged tetrahedra on decompression both in glasses quenched from liquids formed at high-pressure and in glasses compressed at 300 K demonstrates that these species arise from structural reorganizations during decompression. Such reorganizations plausibly involve the breakdown of highly coordinated Si polyhedra and the resultant formation of bridged tetrahedra. The nearly complete decomposition ofthe high-pressure structure in glasses on decompression documents that in situ high-pressure measurements are crucial in deriving accurate constraints on the structure of silicate liquids at high pressure.
Molecular‐beam epitaxial growth of high quality InSb for p‐i‐n photodetectors

We report the growth of high quality InSb p‐i‐n structures which have been optimized using reflection high energy electron diffraction. Optimized InSb p‐i‐n structures of 5.8 μm thickness demonstrated x‐ray full widths at half‐maximums (FWHMs) of 101 and 147 arcsec for GaAs and Si substrates, respectively, and exhibited excellent uniformity and morphology. Prototype InSb p‐i‐n detectors on Si have been fabricated and have demonstrated photovoltaic response at 6.5 μm up to 200 K. A 4.8 μm InSb layer grown on GaAs at a growth temperature of 395 °C and a III/V incorporation ratio of 1/1.2 had an x‐ray rocking curve FWHM of 158 arcsec and a Hall mobility of 92 300 cm2 V−1 s−1 at 77 K.
DDT, DDD, and DDE Dechlorination by Zero-Valent Iron

Traditionally, destruction of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] for environmental remediation required high-energy processes such as incineration. Here, the capability of powdered zero-valent iron to dechlorinate DDT and related compounds at room temperature was investigated. Specifically, DDT, DDD [1,1-dichloro-2,2-bis(p-chlorophenyl)ethane], and DDE [2,2-bis(p-chlorophenyl)-1,1-dichloroethylene] transformation by powdered zero-valent iron in buffered anaerobic aqueous solution was studied at 20 °C, with and without the presence of nonionic surfactant Triton X-114. The iron was successful at dechlorinating DDT, DDD, and DDE. The rates of dechlorination of DDT and DDE were independent of the amount of iron, with or without surfactant. The rates with surfactant present were much higher than without. Initial first-order transformation rates for DDT, DDD, and DDE were determined. For example, the initial first-order rate of DDT dechlorination was 1.7 ± 0.4 and 3.0 ± 0.8 day-1 or, normalized.
A Study of the Diels-Alder Regioselectivity of Substituted Vinyl Cyclohexenes

Abstract The regioselectivity of dienes 6a and 6b in Diels-Alder reactions with ethylenic and acetylenic dienophilic was examined and found to be good-excellent. An improved synthesis of diene 6a via a CuSO4 mediated dehydration of the vinyl carbinol precursor is described.
Self-aggregation of Methylene Blue in aqueous medium and aqueous solutions of Bu4NBr and urea

The self-aggregation of Methylene Blue [MB] (1×10−6–4×10−4 M) in water and in aqueous solutions of Bu4NBr (0.1–0.3 M) and urea (0.1–4 M) has been investigated by recording electronic spectra in the wavelength range 550 to 700 nm. Analysis of the spectral data yielded the dimer dissociation constant, and individual characteristic monomer and dimer spectra. By applying the exciton model for the first time, the interaction energy between the MB molecules in the dimer species has been evaluated. Further, information about the dimer geometry and the twist angle between the dipoles of the MB molecules in the dimer species has been obtained. Similar data have also been obtained for solutions of MB in aqueous urea and Bu4NBr solutions. The significant observation is the change in the dimer geometry from sandwich type to end-on-end type in the presence of urea and Bu4NBr. It is observed that the contribution to the interaction energy is mainly from van der Waal's type and dispersion forces, in addition to short-range forces involving multipoles. However, the contribution from hydrogen-bonding interactions between MB and water molecules is found to be significantly low. It is proposed that water structural effects and hydrophobic interactions are the major factors in the phenomenon of aggregation.
δ18O of tree rings of beech (Fagus silvatica) as a record of δ18O of the growing season precipitation

The measurement of δ 18 O in cellulose of tree rings is a potential means to reconstruct δ 18 O variations of precipitation and climate. We present δ 18 O data from cellulose of 3 beech trees ( Fagus silvatica ) growing on a relatively dry site in Switzerland where the roots do not have access to ground water, as well as data of 2 other groups of 4 beech trees each, one from a dry site and the other from a semi-dry site, respectively. The measurements cover the time period from 1934 to 1987 in 3-year-groups for the 1st site and 1965 to 1992 with a 1-year resolution for the other 2 sites. We find a high degree of common variance (61%) between the δ 18 O variations of the 3 trees from the 1st location suggesting a common external cause. The comparison with climate data indicates that spring temperature (April/May/June) is the main influence for the long-term isotope variations, with a temperature coefficient of 0.33‰ per °C, whereas the short-term variations are mainly influenced by the relative humidity, with a coefficient of – 0.13‰ per %. This latter value is about ⅓ of the expected model value which points to leaf water pools with different δ 18 O values influencing the isotopic composition of synthesised carbohydrates or to oxygen exchange with stem water. Tree ring δ 18 O is correlated with δ 18 O in precipitation, and the slope of the linear regression for different months most probably yield information about the growth rate function of the particular tree group. Our results confirm the potential of δ 18 O measurements in tree ring cellulose for climate reconstruction, in particular information about δ 18 O in precipitation can be gained. DOI: 10.1034/j.1600-0889.49. issue1.6. x
Sorption and biodegradation of 17β-estradiol by acclimated aerobic activated sludge and isolation of the bacterial strain.

Abstract Batch experiments were conducted to investigate the sorption and biodegradation behavior of 17β-estradiol (E2) at low μg·L−1 levels by acclimated aerobic activated sludge as well as the effect of temperature on the sorption and biodegradation. Results showed that E2 was completely transformed after 2 h under aerobic conditions. E2 attenuation was achieved by sorption onto the sludge and the subsequent biodegradation by micro-organisms in the activated sludge. Sorption of E2 onto both the inactivated sludge and the activated sludge was well described by both the Freundlich and linear isotherms. The biodegradation of E2 by the acclimated activated sludge can be described by first-order reaction kinetics with the first-order reaction rate constant of 3.49 h−1 at 20°C. The sorption isotherms and biodegradation kinetics indicated that partitioning played a dominant role in the sorption of E2 on the activated sludge. Temperature exerted significant effects on both the sorption and biodegradation of E2.
Interception of Airborne Particles by Tree Plantings

The ability of tree plantings to abate overland movement of particulate pollutants was examined. Estimates of deposition of dust and of total suspended particles indicated that, in comparison to clearcut sites, tree plantings in both urban and rural locations were effective in reducing the amount of particulate matter in the atmosphere. During an 8-month sampling period, the overall reduction of dustfall by deciduous trees was 30% (rural) and 27% (urban). In comparison, rural and urban coniferous stands reduced dustfall by 42 and 38%, respectively. Interception of total suspended particles was 11% for deciduous trees and 13% for conifers at the rural site, and 9% for deciduous trees and 13% for conifers at the urban site.
Cross Sections for Dissociative Ionization of Molecules by Electron Impact

Cross sections for dissociative ionization have been measured as a function of electron energy from threshold to 1000 eV in nine gases (H2, D2, N2, CO, NO, O2, CO2, N2O, and CH4) by collecting those ions reaching the ion collector after passing through a 0.25‐V retarding potential in a total‐ionization tube. Approximate correction is made for the effective solid angle subtended by the ion collector at the electron beam. The results are reported as the fraction of total ionization, and as absolute cross sections for dissociative ionization. At moderately high electron energies (>70 eV), the fraction of total ionization that is dissociated ions with kinetic energy in excess of 0.25 eV, ranges from ∼7% in H2 and D2 to ∼35% in N2O, with other gases intermediate.
Hétérogénéités ellipsoïdales dans un milieu élastique anisotrope

La methode developpee par Eshelby pour resoudre certains problemes relatifs aux champs de contrainte et de deformation des inclusions est ici etendue aux cristaux anisotropes. Le procede est fonde sur l'emploi de la transformation de Fourier et devient tres simple pour les matrices cubiques. A titre d'exemple, nous examinons une application au calcul des constantes elastiques des solides contenant des heterogeneites.
Effect of metal dispersion on the activity and selectivity of Rh/SiO2 catalyst for high pressure CO hydrogenation.

Metal dispersion has a striking influence on the activity and selectivity of Rh/SiO2 for high pressure CO hydrogenation. Decreasing dispersion, turnover frequency of CO conversion does not change significantly with dispersion up to 0.5 but increases abruptly at dispersion of 0.45. CH3OH is produced selectively at high dispersion. C2-oxygenated compounds are produced favorably for dispersion of 0.25–0.45. CH4 formation increases monotonously with decrease of dispersion.
Heavy metal partitioning in sediments from the lagoon of Venice (Italy)

In this study heavy metal pollution in surface sediments of the Lagoon of Venice (Italy) was investigated. Attention was focused on the evaluation of the amounts of heavy metals that can potentially be released into the overlying water column, under particular environmental conditions, thus becoming bioavailable. To this end, the partitioning of heavy metals among different geochemical phases was determined by a procedure of sequential selective extractions. This approach can provide useful information for assessing the risk posed to the Lagoon ecosystem by metal contaminated sediments and for estimating the anthropogenic heavy metal content. In general, higher levels of contamination were found in sediments sampled in areas situated in the proximity of sources of pollutants and in degraded sites, which presented limited water circulation and prevailing anoxic conditions. The results of the sequential extraction procedure showed that partitioning is dependent on the metal considered: in particular, Pb, Cu, Zn and Cd were bound mainly to the most labile phases of sediments, whereas Cr and Ni were found prevalently in the residual fraction.
The wurtzite to rock salt structural transformation in CdSe nanocrystals under high pressure

Structural transformations in CdSe nanocrystals are studied using high pressure x‐ray diffraction and high pressure optical absorption at room temperature. The nanocrystals undergo a wurtzite to rock salt transition analogous to that observed in bulk CdSe. Both the thermodynamics and the kinetics of the transformation, however, are significantly different in finite size. The nanocrystal phase transition pressures vary from 3.6 to 4.9 GPa for crystallites ranging from 21 to 10 A in radius, respectively, in comparison to a value of 2.0 GPa for bulk CdSe. The size dependent data can be modeled using thermodynamics when surface energies are accounted for. Surface energies calculated in this way can be used to understand the dynamic microscopic path followed by atoms during the phase transition. X‐ray diffraction data also shows that unlike bulk CdSe, crystalline domain size is conserved upon multiple transition in the nanocrystals, indicating that the transition only nucleates once in each nanocrystal.
Comparative Phytochemical Evaluation of Dissotis rotundifolia Root and Leaf

Dissotis rotundifolia is a common medicinal plant in Nigeria. Quantitative phytochemical analyses were carried out in both dry leaf and root samples using spectrophotometric method. The result of phytochemical analysis of the root revealed the presence of alkaloids (463.20±6.70mg/100g), polyphenol (179.80±0.66 mg/100g), flavonoids (144.40±5.60mg/100g), phenol (13100±6.86mg/100g), tannin (126.80±1.76mg/100g), cyanogenic glycoside (75.20±2.20 mg/100g), anthraquinone (40.64±1.26 mg/100g), sapoginin (29.00±0.02 mg/100g), anthocyanin (11.50±1.10mg/100g) and saponin (0.90±0.60 mg/100g). The result also revealed the presence of alkaloids (155.00 ± 38.32mg/100g), phenols (110.80 ± 3.42 mg/100g), polyphenols (139.50 ± 8.08 mg/100g), tannins (89.88 ± 1.84 mg/100g), flavonoids (58.80 ± 5.25 mg/100g), cyanogenic glycosides (58.24 ± 1.76 mg/100g), anthraquinones (27.94 ± 6.04 mg/100g), anthocyanin (13.04 ± 0.87mg/100g), saponins (3.20 ± 0.14mg/100g) and sapoginin (3.09 ± 0.04 mg/100g) in the leaf sample. The results indicate that the leaf and seed of Dissotis rotundifolia contains appreciable amount of bioactive compounds. Medically the presence of these phytochemicals explains the use of these plant parts in ethnomedicine for the management of ailments.
Synthon preferences in cocrystals of cis-carboxamides:carboxylic acids

We study synthon preferences in cocrystals of cis-carboxamides with carboxylic acids using a combination of database analyses, cocrystallisation experiments and theoretical calculations. We classify the cis-carboxamides into three families: primary amides, cyclic amides (lactams) and cyclic imides. Using crystal structure prediction calculations, we sample the phase space of the cocrystals and generate observed as well as non-observed cocrystal structures and synthons in order to compare their relative stability as calculated with the PIXEL method. We conclude our study with a set of rules of synthon preferences derived from our observations and theoretical calculations. Whilst primary amides almost always form heterosynthons with carboxylic acids, cyclic imides seldom crystallise with them and cyclic amides represent a difficult prediction challenge. The study highlights the role played by the side interactions in the stability of the studied synthons.
Fiber-Optic Chemical Nanosensors by Electrostatic Molecular Self- Assembly

A review of optical fiber sensors based on nanostructured coatings fabricated by means of the layer-by-layer electrostatic-self assembly (ESA) method is presented here. The modification of the optical properties of these sensing coatings by the target parameter can induce changes in the reflected or transmitted spectrum. This property can be ex- ploited for the development of refractometers, pH sensors, chemical sensors, biosensors and other applications. In addition to the experiments performed, the theory of some of these phenomena have been also studied in order to understand the behavior of the sensors and to improve their sensing characteristics.
Determination of strontium isotope ratio of brown rice for estimating its provenance

Abstract The strontium isotope ratio (87Sr / 86Sr) of brown rice (Oryza sativa L.) was determined by multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS) in order to evaluate the values of 87Sr / 86Sr for use in the estimation of the area of rice production. Sample solutions were prepared from 5 g of rice samples using the acid (HNO3-HClO4-HF) digestion method. Removal of rubidium from the sample solutions was performed using ion-exchange resin (Dowex 50W X8). The Sr isotope ratios were determined with a precision of < 0.01% (RSD, repetitions = 60) by MC-ICP-MS. Typical analysis time for a single sample was about 15 min, reflecting the high sample throughput. The Sr isotope ratios of the Japanese rice samples ranged from 0.706 to 0.709. The Sr isotope ratios of the Chinese and Vietnamese rice samples (0.710 to 0.711) were slightly higher than those of almost all the Japanese samples. Australian rice showed the highest Sr isotope ratio (0.715 to 0.717) among all the rice samples examined. In contrast, the Sr isotope ratio of Californian rice (0.706) was lower than that of almost all the Japanese samples. The variation in the 87Sr / 86Sr ratios for the rice samples analyzed in this study clearly demonstrated that the Sr isotope ratios could provide a key information for the estimation of rice provenance.
IR Drying of Water-Based Acrylic PSA Adhesives

Results of infrared drying of an acrylic microsphere adhesive coating are presented. The effect of IR drying on adhesive coating was analyzed by Fourier transform infrared spectroscopy (FTIR). The adhesion strength was tested by peel adhesion measurement. Drying was experimentally carried out on materials dried to the same moisture extent at different operating conditions. The power of IR heating source, time of drying, and distance between adhesive coating and heating source were varied. The developed phenomenological model was compared with existing empirical models.
Bond strength and sulfur isotopic fractionation in coexisting sulfides

9Bond strengths in sulfides are estimated from heats and free energies of formation, lattice energies, and other indirect, largely empirical methods.9 Sequences, from greatest to least enrichment in S-34, predicted from bond strength, are pyrite, sphalerite, chalcopyrite, galena; and pyrite, pyrrhotite, chalcopyrite, bornite, chalcocite. Where a reasonable amount of data exists, the systematic and consistent patterns in naturally occurring coexisting sulfides indicate an approach to isotopic equilibrium, and validate the use of estimates of bond strength to predict fractionation patterns among sulfides formed under equilibrium conditions.
GAS-LIQUID DISPERSION WITH PITCHED BLADE TURBINES

Abstract The performance of pitched blade turbines in a gas-liquid dispersion has been studied. The two-phase hydrodynamics, gassed power consumption and mass transfer properties have been examined using six blade open turbines with blade angles from 30 to 60 degrees to the horizontal, mounted for down flow. There are two distinct regimes by which gas leaving the sparger reaches the impeller: at low gas rates this is indirect via the recirculation loops, while at higher gas flow rates the flow is direct. The transition between these regimes is reflected in power consumption and mass transfer characteristics and is related to the formation of large cavities behind the blades. It was also concluded that, with respect to mass transfer efficiency, a pitched blade turbine is at least as good as a Rushton turbine.
Responses of Canola Morphological and Agronomic Characteristics to Zeolite and Zinc Fertilization under Drought Stress

Research was performed during the 2010 and 2011 growing seasons to investigate the effect of zeolite and zinc (Zn) foliar application on the qualitative characteristics and oil yield of canola cultivars at different moisture regimes. A factorial split-plot experiment was performed on the basis of the randomized complete block design with three replications in the Seed and Plant Improvement Institute, Karaj, Iran. The treatments were as follows: (1) irrigation (I), complete (I1), and restricted (I2) at the pod formation stage, (2) zeolite (Z), 0 (Z1), and 15 t ha−1 (Z2), and (3) Zn, zinc sulfate concentrations of 0%, 0.1%, and 0.2 % (Zn1, Zn2, and Zn3) at the pod formation stage. These treatments were applied on Licord, RGS003, and Opera cultivars. The results show that the simple effect of treatments were statistically significant for all assessed traits at P < 0; as well as the interaction effects of Z and Zn (P < 0.01) and the interaction effects of I and cultivar (P < 0.01). The greatest rates of all studied traits were obtained by applying Z2Zn2 (15 ton ha−1 zeolite and 0.1% Zn sulfate) in both irrigation regimes. The rates of grain yield, biological yield, and harvest index improved by 43.82%, 73.99%, and 30.04%, respectively, using a combined application of Z and Zn. Therefore, based on the low cost of natural Z and a low Zn intake, these treatments could be used to enhance the performance of canola, especially in regions that are exposed to water stress.
Uncertainty quantification in thermochemistry, benchmarking electronic structure computations, and Active Thermochemical Tables

The accepted convention for expressing uncertainties of thermochemical quantities, followed by virtually all thermochemical tabulations, is to provide earnest estimates of 95% confidence intervals. Theoretical studies frequently ignore this convention, and, instead, provide the mean absolute deviation, which underestimates the recommended thermochemical uncertainty by a factor of 2.5–3.5 or even more, and thus may vitiate claims that “chemical accuracy” (ability to predict thermochemical quantities within ±1 kcal/mol) has been achieved. Furthermore, copropagating underestimated uncertainties for theoretical values with uncertainties found in thermochemical compilations produces invalid uncertainties for reaction enthalpies. Two groups of procedures for determining the accuracy of computed thermochemical quantities are outlined: one relying on estimates that are based on experience, the other on benchmarking. Benchmarking procedures require a source of thermochemical data that is as accurate and reliable as possible. The role of Active Thermochemical Tables in benchmarking state-of-the-art electronic structure methods is discussed. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. International Journal of Quantum Chemistry published by Wiley Periodicals, Inc.