Miracle-dz/UniFAR-FTUs huggingface dataset:
Assessment of the Use of Microcrystalline Silicon Materials Grown at Rates Near 15 Å/s as i-layer Material for Single and Multi-Junction Solar Cells

A microwave-based technique has been used to prepare microcrystalline Si (µc-Si) materials rates near 15 A/s. The use of these materials as intrinsic layers (i-layers) for single and multi-junction devices has been assessed. Since the high deposition rates allow for fabrication of the required thicker µc-Si i-layers in a similar amount of time to that used for high quality a-SiGe i-layers (rates of 1-3 A/s), the materials are attractive, low cost replacements for a-SiGe bottom cell i-layers in a-Si/a-SiGe and a-Si/a-SiGe/a-SiGe multi-junction cells. Single-junction nip, a-Si/µc-Si and a-Si/a-SiGe/µc-Si devices have been fabricated. For these devices, the doped and amorphous layers were deposited using conventional rf glow discharge processes and deposition equipment separate from that used to fabricate the µc-Si materials. 7.0% efficiencies have been achieved for single-junction devices while pre-light soaked 9.8 and 11.4% efficiencies have been achieved for the tandem and triple-junction devices, respectively. The single-junction devices exhibit a degradation of only 0-2% after long term (1000 hrs.) of light soaking demonstrating a high degree of stability. Based on the present status, the µc-Si material prepared at high rates qualifies as a reasonable candidate for the i-layer of a bottom cell of a triple-junction device. Improvements in the performance, particularly the FF, will be needed before use in single-junction and tandem devices can be considered.
Compression of iron hydride to 80 GPa and hydrogen in the Earth's inner core

Here we report a new data on the equation of state of iron hydride up to 80 GPa measured by an in situ X‐ray diffraction method. We observed anomalous compression behavior at 30 to 50 GPa, and found that iron hydride might be less compressible above 50 GPa than at lower pressures. The bulk modulus above 50 GPa is larger than that of pure hcp‐iron. Our data support the ab initio calculation suggesting a magnetic transition of iron hydride at around 60 GPa. The density deficit of the Earth's inner core could be explained by dissolution of smaller amount of hydrogen than previously suggested.
Raman study of the solid‐state polymerization of acetylene at high pressure

The mechanism and kinetics of the pressure‐induced polymerization of acetylene were studied by Raman spectroscopy. The polymerization reaction occurred in the orthorhombic phase at room temperature and pressures above 3.5 GPa. Dominant formation of trans‐polyacetylene suggested that the monomer underwent trans opening of the triple bond and polymerized along the diagonal of the bc plane of the unit cell. The reaction was described as an idealized one‐step and one‐dimensional growth process by an Avrami equation with an exponent 1.34.
Protein partitioning in two-phase aqueous polymer systems. 1. Novel physical pictures and a scaling thermodynamic formulation

A new molecular thermodynamic description of the interactions of globular proteins and flexible nonionic polymers, which influence the partition of proteins in two-phase aqueous polymer systems is presented. The changing nature of the polymer solution phase from one of identifiable polymer coils to one of an entangled web or net of polymers, with increasing polymer molecular weight is described. In addition to the novel physical pictures proposed for the interactions of polymers and proteins in two-phase aqeous polymer systems, descriptions are proposed for the free energy of interaction within each of the pictures and this quantity is related through a statistical thermodynamic framework to the experimentally measured protein partition coefficient
A neutron-diffraction study of very pure chromium

Single crystal and polycrystalline samples of pure chro mium (0.01% oxygen, 0.001% nitrogen, 0.0002% metallic impurities by weight) lose the major portion of their antiferromagnetic ordering at 40 deg C, but there remains some residual order in polycrystalline material and this increases with reduction of grain size. In all cases it is concluded that the magnetic moment on the chromium atom, well below the Neel temperature, is about 0.45 mu /sub B/. With addition of 0.5% of iron and 0.16% of nickel the Neel temperature is lowered to 26 deg C. (auth)
Effect of Substituents on Radical Stability in Reversible Addition Fragmentation Chain Transfer Polymerization: An ab Initio Study

The effects of the R- and Z-substituents on radical stability in the reversible addition fragmentation chain transfer (RAFT) polymerization process have been studied via high level ab initio molecular orbital calculations. Radical stabilization energies (RSEs) of the RAFT-adduct radicals CH3SC•ZSR and corresponding leaving group radicals R• have been calculated for various combinations of Z = H, Cl, C⋮CH, CHCH2, CN, CF3, NH2, CH3, Ph, Bz, naphthyl, OCH3, OCH2CH3, OCH(CH3)2, and OC(CH3)3 and R = CH2CN, C(CH3)2CN, Bz, CH(Ph)CH3, C(Ph)(CH3)2, CH2COOCH3, CH(COOCH3)CH3, CH2OCOCH3, and CH2CH3. The results were used in combination with the corresponding values of the enthalpies of the fragmentation reactions, CH3SC•(Z)SR → CH3SC(Z)S + •R and CH3SC•(Z)SR → •CH3 + SC(Z)SR, to examine the effects of the substituents on the stability of both the RAFT-adduct radicals and the corresponding thiocarbonyl compounds. The RAFT-adduct radicals are stabilized by electron donation from the two sulfur substituents, and this st.
A study of the structure of highly concentrated phases of DNA by X-ray diffraction

In aqueous solution, pure DNA forms multiple liquid crystalline and crystalline phases whose nature depends on the polymer concentration. The following phase sequence is observed when the DNA concentration increases : isotropic ↦ cholesteric ↦ columnar hexagonal ↦ crystalline phases. The aim of this work is to obtain structural information about the highly concentrated phases formed by 500 A long DNA molecules — in particular about the crystalline phases — by means of X-ray diffraction. We show that in the two-dimensional (2D) ordered hexagonal phase a longitudinal order progressively appears between neighbouring DNA helices leading continuously to a three-dimensional (3D) ordered hexagonal phase. For higher concentrations the specimens undergo a discontinuous transition towards an orthorhombic phase. The characteristic structural parameters of these different phases have been determined. An important result is that the number of nucleotides per helix turn decreases continuously, when the DNA concentration increases, from 10.3±0.1 at the cholesteric ↦ hexagonal transition down to 9±0.1 without any apparent change of the B conformation of the molecules.
Large electric field-induced strain and antiferroelectric behavior in (1-x)(Na 0.5 Bi 0.5 )TiO 3 -x BaTiO 3 ceramics

The dielectric, ferroelectric, and electric field-induced strain response of (1-x)(Na0.5Bi0.5)TiO3-xBaTiO3 (NBT-BT) (0.04 ≤ x ≤ 0.10) ceramics has been systematically investigated as a function of temperature. It is found that ferroelectric and antiferroelectric (AFE)-like behavior can coexist at temperatures significantly lower than the depolarization temperature Td (even down to as low as ambient temperature). Electron microscopy suggests that such behavior results from the electric field-dependence of fine scale octahedral tilt twinning disorder and the associated disorder in the local (ferroic) off-center displacements of the Na/Bi/Ba and Ti ions. The existence of the AFE-like behavior significantly enhances the electric field-induced strain. High bipolar strain of 0.40% and unipolar strain of 0.27% has thereby been achieved at ambient temperature in an NBT-BT, x = 0.07, ceramic. The bipolar and unipolar strains reach almost identical maximum values when the temperature is close to Td. Giant unipolar .
Elaboração de bolo de mel enriquecido com fibras do bagaço da indústria cervejeira

A industria cervejeira, ao longo de seu processamento, gera grandes quantidades de residuo, um dos mais descartados e o da materia prima utilizada para a preparacao do mosto cervejeiro, conhecido como bagaco de cerveja. Esse residuo constituido por um alto teor fibras e destinado em sua grande maioria para a alimentacao animal. As fibras alimentares vem despertando interesse de especialistas das areas de nutricao e saude por seus beneficios a saude. Foi utilizado mel nas formulacoes por tambem ser um alimento com propriedades beneficas a saude. O consumo de mel no Brasil e considerado baixo comparado a outros paises, a utilizacao do mesmo nas formulacoes possibilita o aumento de seu consumo com uma nova opcao, alem da “in natura”, a forma mais consumida. Esse trabalho teve como objetivo elaborar um produto destinado a alimentacao humana a base de bagaco de cerveja e mel, bem como promover sua avaliacao e estimar o nivel de aceitabilidade. Foram elaboradas duas formulacoes finais, com 7% e 10,5% de bagaco de cerveja. O bagaco de cerveja utilizado apresentou 40% de fibras e os produtos elaborados podem ser denominados como ”rico em fibras” por apresentarem mais de 6% de fibras em sua composicao. Ambas as formulacoes de bolo de mel enriquecido com fibras classificaram-se dentro dos padroes microbiologicos tornando-se seguros ao consumo. O indice de aceitabilidade (IA%) foi maior que 80% nos atributos: impressao global, cor, aroma, textura e sabor. Com os resultados obtidos espera-se valorizacao do residuo, aumentando seu valor agregado e consequentemente, trazendo beneficios para industria cervejeira.
The Release and Bioactivity of Lysozyme from Selected Sol-Gel Derived SiO2 Matrices

Local drug release has many benefits – a steadier distribution, improved compliance, but most importantly it allows the convenient use of protein based molecules as therapeutic agents. Many different types of materials have been studied as drug carriers, including sol-gel derived SiO2 matrices. In this study lysozyme was used as a model protein and its release from prepared SiO2 monoliths and its biological activity thereafter was studied spectroscopically. Sucrose was used in some preparations to assess its ability to function as a protective agent during storing. Lysozyme release and bioactivity was similar in both preparations containing it when tested fresh. In monoliths stored for ten weeks, however, differences were observed in the biological activity of released lysozyme. In the preparations containing sucrose, lysozyme had retained its activity, while it was virtually nil in the preparations containing only lysozyme. This shows that sol-gel derived SiO2 matrices can be used as carriers for small proteins and that sucrose can function as a protective agent in them.
Microscopic protonation equilibria of Poly(amidoamine) dendrimers from macroscopic titrations

Poly(amidoamine) (PAMAM) dendrimers of generations G0, G1, G2, G3, G4, and G6 are investigated by potentiometric (acid−base) titrations. The data are interpreted with a site binding model, which offers the possibility to model the titration curves for all generations of the dendrimers and to describe all dendrimers within a common parameter set. These parameters involve the microscopic ionization constants for each group in the fully deprotonated state and nearest-neighbor pair interaction parameters. From this model we can further obtain all microscopic ionization constants as well as conditional microstate probabilities. The protonation of PAMAM dendrimers first involves protonation of primary amine groups at the outer rim of the dendrimer at high pH, while the tertiary amine groups in the dendrimer core protonate at lower pH. The last group to protonate at low pH is a central tertiary amine.
Large Vacuum Rabi Splitting in Single Self-Assembled Quantum Dot-Nanocavity System

We report on the observation of the strong-coupling regime in a single InGaAs self-assembled quantum dot (QD) and photonic crystal nanocavity system. There was a strong interaction between the QD exciton and discretized photon mode and the strong coupling was manifest in photoluminescence data, which displayed a distinct anti-crossing in temperature tuning measurements. A vacuum Rabi splitting of 180 µeV was observed, which was larger than the values given in previous studies with clear exciton polariton modes. In addition, the exciton-photon coupling strength amounted to about 90 µeV. A distinct energy mixing, which resulted from the reversible photon emission process of a QD, was also observed when the system formed a QD exciton polariton state.
Nonhydrolytic Route for Synthesis of ZnO and Its Use as a Recyclable Photocatalyst

A simple, convenient and versatile synthetic approach has been demonstrated for large-scale synthesis of zinc glycerolate microcrystals having preferential growth along the (100) axis. Glycerol has been used both as a ligand and as a solvent. This glycerolate precursor has subsequently been converted into the hexagonal phase of zinc oxide (ZnO) with wurtzite structure by calcining in air. A number of techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, solid-state 13C NMR spectroscopy, and thermogravimetric analysis (TGA) measurements have been used to investigate the morphology, crystallinity, and structure of the products obtained before and after calcination. Furthermore, the room-temperature photoluminescence (PL) of the ZnO nanocrystals has also been investigated along with rhodamine B degradation. The latter has been used as a probe reaction to evaluate the photocatalytic performance.
Distribution of polycyclic aromatic hydrocarbons among different compartments of a river ecosystem

Distribution of PAHs in a river ecosystem was studied by sampling of four abiotic compartments (surface water, suspended matter, pore water and sediments) under two different hydro‐logical conditions. PAHs were detected at significant concentrations in both the solid and aqueous phase of the river ecosystem. Water concentrations were relatively low despite greater contamination of sediments. Lower MW PAHs were prevailing in the dissolved phase, higher MW PAHs in particulate materials. Concentrations of PAHs in surface waters were greater in summer than in fall. PAHs composition in the sediments was found to be relatively uniform across sites reflecting combustion generated PAH profile. Correlation and multivariate statistical analysis have shown differences between PAH patterns in solid and water samples. In aquatic samples and suspended matter, principal component analysis distinguished two separated groups of PAHs with different distribution depending on their molecular weight. In‐situ partition coefficients between the solid and aqueous phase did not differ very much between seasons. The role of organic carbon for PAHs partitioning to sediments in situ was examined. PAHs concentrations correlated to OC content only in summer. In‐situ Kocs were up to two orders of magnitude greater than tabulated Kocs based on the equilibrium partitioning model. The main reasons are the lower availibility of PAHs bound to particles from combustion sources to partition into the aqueous phase and dynamic conditions in the river ecosystem which do not enable the full equilibrium to appear.
Optimization of a Sequential Anaerobic-Aerobic Treatment of a Saline Fishing Effluent

Optimization of a sequential anaerobic-aerobic treatment system to determine ideal reactor sizes for reduction of organic matter (COD) in fishing effluents to legal standards at minimal costs was performed. Calculations for the sequential degradation of effluents for a base case were carried out by an objective function involving process optimization and investment-operation cost related to treatment yield in each reactor. Process optimization considering individual equipment volumes based on biological kinetics gave a minimum total volume for a conversion yield of 0.77 in the anaerobic reactor. The objective function turned out a monotonous decreasing function within the 0–85% conversion yield range of the anaerobic digester. The minimum total cost was found at the superior limit (85%) of the conversion range. Exclusion of the anaerobic step increases by eight times the cost to reach the same level of COD reduction shown by sequential treatment. Experiments at bench scale showed that this system reduces the COD of a base case effluent to 600 mg l−1, but the final nitrogen content (810 mg 1−1) remains far above the legal limit (50 mg l−1). Parametric sensitivity analysis showed that total annual cost is an increasing exponential function of the COD concentration, an increasing linear function of the energy cost, a decreasing linear function of the COD legal limit and is almost insensitive to oxygen cost. However, aerobic degradation is 27% cheaper by using oxygen instead of aeration. Implementation of the sequential system requires an annual capital investment of US$ 196,000 year−1 and a discounted operation cost of US$ 138,000 year−1. The cost of a plant designed to comply with the COD legal limit (160 mg l−1) is relatively low as it would only increase the price of fishmeal by 1.0% per tonne.
A configurational-bias approach for the simulation of inner sections of linear and cyclic molecules

A novel Monte Carlo technique, the rebridging configurational-bias (RCB) method, has been developed to rearrange inner sections of chain molecules having strong intramolecular interactions along the backbone. The ability of sampling inner chain segments is important for the simulation of systems with low concentration of chain ends, such as polymers and molecules with cyclic structures. In the RCB method, inner segments are removed and then regrown site-by-site in a configurational-bias fashion. However, a short preliminary simulation is carried out to calculate weighting functions based on histograms of the separation distance between pairs of sites along the chain; these functions are used to bias the trial positions of growing inner sites so as to promote efficient chain closure. A look-ahead search scheme is employed for the sampling of the last two sites to increase the overall acceptance rate of the reconstruction process. The validity and performance of the new algorithm were tested by studying linear alkane systems of various chain lengths. Fast conformational equilibration was observed, from the level of local bond orientations to the level of the chain end-to-end vector orientations. Cyclic alkanes containing from 8 to 100 carbon atoms were also studied by using the RCB method. Our results for the conformational properties of cyclooctane are generally consistent with previous molecular dynamics (MD) results and with experimental data. The vapor–liquid coexistence curve of cyclooctane was also mapped out by using the RCB method in conjunction with a histogram reweighting technique for the analysis of isothermal–isobaric simulations.
Synthesis and characterization of new methacrylate-type hydrogels containing 2-tert-butylamino ethyl groups for sorption purposes

Crosslinked poly[2-(tert-butylamino)ethyl methacrylate] (PtBAEMA) hydrogels were synthesized by 60Co-γ-radiation-initiated simultaneous polymerization and crosslinking of 2-(tert-butylamino)ethyl methacrylate in bulk and in aqueous solutions. The results showed that the gelation percentage decreased with increasing water content. The structural and thermal characterizations of the hydrogels were accomplished with several techniques, including Fourier transform infrared spectroscopy, swelling measurements, thermogravimetry, and differential scanning calorimetry. The effects of time, pH, temperature, and ionic strength on the swelling behavior were also investigated. Swelling equilibrium was attained in 2–3 days. PtBAEMA hydrogels originally swelled to 350% (by volume) in deionized water, but this value reached 3000% around pH 2.0. PtBAEMA hydrogels were reversibly affected by the change in temperature within the temperature range of 4–70°C. The swelling ratios of the gels decreased with increasing ionic strength. As a result, PtBAEMA hydrogels show stimuli-responsive properties depending on the characteristics of the environment, and they are being considered for adoption as some kind of carrying material for separation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
INORGANIC SYNTHESIS AND INDUSTRIAL INORGANIC CHEMISTRY Complex Formation in the Course of Synthesis of Zinc Oxide from Citrate Solutions

Complex formation of zinc(II) with citric acid in acidic medium was studied by pH-potentiometric titration at various metal to acid ratios. The speciation diagrams of the complexes in relation to pH were plotted, and the stability constants of the complexes were determined. Precursors of the synthesis of metal oxide materials were prepared at two reactant ratios. A scheme of the precursor thermal decomposition based on data of derivatography and IR spectroscopy was suggested, and the compositions of compounds formed during decomposition were determined.
A new method for the analysis of phenolic groups in lignins by ʹH NMR spectrometry

H& I SUMMARY: Phenolic groups in lignins were analysed by 'H NMR spectrometry at 400 and 500 MHz (DMSO-d6 solution, temperature 300 K). Under these conditions the majority of the signals from protons in phenolic hydroxyl groups are found in the spectral range 6 8.0-9.3. Most carbonyl-conjugated phenols give signals at 6 values >9.3; the corresponding types of lignin units constitute only a very small fraction of the phenolic groups. The number of phenolic groups in milled wood lignin (MWL) from spruce was estimated as 0.24/phenylpropane unit; phenolic groups in biphenyl and diary1 ether structures constituted about 20% of the total number of phenolic groups. Spectra of MWL from birch exhibited separate peaks for phenols in guaiacyl units (628.8) and syringyl units (628.2); the total number of phenolic groups was estimated as 0.18/phenylpropane unit. The proportion of phenols in guaiacyl units was larger than that of syringyl units.
Dynamics of the activated dissociative chemisorption of N2 on W(110): a molecular beam study

Molecular beam techniques have been used to study the dissociative chemisorption of nitrogen on W(110). Chemisorption probabilities have been measured as a function of incidence angle θi and kinetic energy Ei surface coverage and temperature. In addition, angular scattering distributions have been measured for a range of conditions and LEED has been used to examine surface structure. The initial (zero coverage limit) sticking probability is found to depend strongly on the incidence energy, scaling approximately with Ei, rather than with the velocity component normal to the surface. This probability is ≤3×10−3 for Ei≤30 kJ mol−1, and rises by more than a factor of 100 by ∼100 kJ mol−1, where it levels off at ∼0.35. It is argued that this behavior arises due to a strong chemical interaction prior to the barrier to dissociation. Angular scattering distributions revealed predominately quasispecular scattering with evidence as well for a diffuse component at low energies. The sticking probability falls steadil.