Miracle-dz/UniFAR-FTUs huggingface dataset:
Modeling of Sonos Memory Cell Erase Cycle

This paper investigates the Silicon-oxide-nitride-oxide-silicon (SONOS) memory cell erase cycle. A nonquasi-static (NQS) MOSFET model was developed and implemented in software. The model equations were incrementally solved at each time step. During an erase cycle, a negative pulse is applied to the gate which causes Fowler-Nordheim tunneling between the floating gate and channel. The SONOS floating gate voltage, tunneling current, and threshold voltage were characterized during this erase cycle. Comparisons were made between the model predictions and experimental data for the threshold voltage.
Risks of Boron Toxicity in Canola and Lupin by Forms of Boron Application in Acid Sands of South-Western Australia

Boron (B) deficiency frequently occurs on soils that are low in organic carbon (C) (<1.0% organic C), pH (soil pHCa <5.0), and clay content (<5% clay). Acid sands with these soil properties are common in south-western Australia (SWA). Moreover, hot calcium chloride (CaCl2) extractable B levels are commonly marginal in the acid sands of SWA. This study examined the effects of soluble and slow release soil-applied B fertilizer and foliar B sprays on crops most likely to respond to B fertilizer on these soils, canola (oil-seed rape, Brassica napus L.) and lupin (Lupinus angustifolius L.). At 25 sites over three years, canola was grown with (0.34 kg ha-1) or without B applied as borax [sodium tetraborate decahydrate (Na2B4O7·10H2O) 11% B], and this was followed by nine experiments with B rates [0, 0.55, 1.1 kg ha−1, applied as borax or calcium borate (ulexite, NaCaB5O6(OH)6·5(H2O), 13% B] and foliar sprays (0.1% solution of solubor, 23% B) in 2000–2001. A further five sites of B rates and sources experiments were carried out with lupin in 2000–2001. Finally, foliar B sprays (5% B w/v as a phenolic complex) at flowering were tested on seven sites in farmers’ canola crops for seed yield increases. No seed yield increases to soil-applied B were found while foliar B application at flowering increased canola seed yield in only one season across seven locations. By contrast, borax fertilizer drilled with the seed at sowing decreased canola seed yield in nine of 34-farm sites, and decreased lupin yield in two of five trials. Toxicity from drilled boron fertilizer decreased yield could be explained by decreases in plant density (by 22–40%) to values lower than required for optimum seed yield. Seedling emergence was decreased by borax applied at sowing but less so by calcium borate. Foliar B spray application never reduced seed yield due to toxicity effects. Boron fertilizer drilled with the seed increased the B concentration in plant dry matter at early to mid-flowering. Boron application decreased the oil concentration of grain of canola at four sites. The oil yield of canola was significantly decreased at seven sites. Notwithstanding the marginal B levels on acid sands of the SWA region, care needs to be taken on use of borax fertilizer as toxicity was induced in canola and lupin; with 0.34 to 1 kg B ha−1(3-10 kg borax ha−1) at sowing depressing seed yield, mostly by decreasing plant density. Rather than making general recommendation for B fertilizer application based on 0.01M CaCl2 soil extractable B, soil and plant analysis should be used to diagnose B deficiency and B fertilizer use limited to calcium borate or foliar borax rather than soil-applied borax on low B sands.
Sequence Analysis of Polyether-Based Thermoplastic Polyurethane Elastomers by 13C NMR

In this Note we would like to report on the analysis of the microstructure of segmented polyurethanes by 13CNMRmaking use of the signals arising from nonprotonated aromatic carbons which appear to be sensitive to dyads sequence distribution. The polyurethanes here studied were obtained from poly(tetramethylene glycol) (PTMG) as macrodiol soft segment, 1,4-butanediol (BD) chain extender, and 4,40'-methylenediphenyl diisocyanate (MDI) as hard segment.The results obtained in this work provide a relatively simple and reliable method to determine the microstructure of MDI-based thermoplastic polyurethanes by means of the NMR technique.
Mechanism of Photoreductive Extraction of Vanadium in a Liquid−Liquid Extraction System Using Bis(2-ethylhexyl)phosphoric Acid

The mechanism for the extraction of V, when effected by the photochemical reduction of V(V) to V(IV), was investigated, employing bis(2-ethylhexyl)phosphoric acid as the extractant, n-dodecane as the diluent, and a xenon lamp as the light source. The photochemical reduction of V(V) progresses at a rate that is first order with respect to the concentration of V(V) in both aqueous and organic solutions. Reduction also occurs, in the extraction system, at the interface between the aqueous and organic phases. The observed time-course variation in the distribution ratio with respect to photoirradiation is expressed successfully by a proposed scheme, in which the photochemical reduction of V(V) is a rate-determining step. The organic solution obtained following photoirradiation can be reused for repeated photoreductive extraction−stripping processing.
Amino Acid-Containing Polyacetylenes: Synthesis, Hydrogen Bonding, Chirality Transcription, and Chain Helicity of Amphiphilic Poly(phenylacetylene)s Carrying l-Leucine Pendants

l-Leucine−phenylacetylene adducts 6 and 14 undergo self-association in concentrated solutions and heterocomplexation with solvent molecules through hydrogen bond formation. The adducts are polymerized by rhodium catalysts into poly(4-ethynylbenzoyl-l-leucine methyl ester) (1e) and poly[11-(4-ethynylphenoxy)undecanoyl-l-leucine methyl ester] (2e), with the polymerizations of 6 producing polymers with high molecular weights (Mw up to 1.47 × 106) and high stereoregularity (Z content up to 100%) in high yields (up to 92%). The ester groups of “polyesters” 1e and 2e are selectively hydrolyzed under basic conditions to afford “polyacids” 1a and 2a carrying free leucine pendants. The polymers are thermally stable (up to ∼260 °C) and undergo Z−E isomerization at ∼200 °C. The chirality transcription from the l-leucine pendants induces the chain segments of polymers 1 to helically spiral predominantly in one preferred direction, while the helicity induction processes in 2 are interrupted by the relaxations of the l.
Energy distribution and quantum yield for photoemission from air-contaminated gold surfaces under ultraviolet illumination close to the threshold

The kinetic energy distributions of photo-electrons emitted from gold surfaces under illumination by UV-light close to the threshold (photon energy in the order of the material work function) are measured and analyzed. Samples are prepared as chemically clean through Ar-ion sputtering and then exposed to atmosphere for variable durations before quantum yield measurements are performed after evacuation. During measurements, the bias voltage applied to the sample is varied and the resulting emission current measured. Taking the derivative of the current-voltage curve yields the energy distribution which is found to closely resemble the distribution of total energies derived by DuBridge for emission from a free electron gas. We investigate the dependence of distribution shape and width on electrode geometry and contaminant substances adsorbed from the atmosphere, in particular, to water and hydro-carbons. Emission efficiency increases initially during air exposure before diminishing to zero on a timescale of.
Structure and stability of water chain in a carbon nanotube

Water molecules form a single-file chain structure in a (6, 6) carbon nanotube (CNT), and this stability is different from that of water molecules confined in CNTs with larger diameters, let alone the bulk. Using the molecular dynamics (MD) method and quantum mechanical (QM) calculations, we investigate the characteristics in the context of density dependence of the collective structure and hydrogen bond behavior. The results obtained from MD show that high water density leads to substantially longer hydrogen bond lifetimes. On the other hand, the hydrogen bond lifetime does not noticeably decrease with decreasing density but remains roughly the same when the density is lower than a certain critical value. The mean molecular orientation angle of the water molecule, defined by the angle that comprises the water dipole moment and the CNT axis, is smaller for higher densities, and asymptotically approaches 33° on the low density side. Such an asymptotic nature of the structure and stability stems from non-uniform distribution of water molecules. The mean orientation angle obtained from QM calculations using density functional theory coincides with the MD result. QM analysis also suggests that the charge distribution of water in the CNT originates from the molecular configuration due to spatial confinement rather than strong electronic interaction between water and the CNT.
HYDROGEOLOGICAL INVESTIGATIONS OF CHAPAI NAWABGANJ TOWN OF NAWABGANJ DISTRICT, NORTH-WEST BANGLADESH USING ISOTOPE AND OTHER TECHNIQUES

Groundwater of Chapai Nawabganj town has been studied using hydrogeological, hydrochemical and environmental isotope (δ 18 O, δ 2 H, δ 13 C, 3 H and 14 C) data. Aquifer underneath the study area is divided into unconfined to semi-confined Holocene alluvial floodplain aquifer and confined Plio-Pleistocene Dupi Tila sandstone aquifer. Chemical composition of groundwater is characterized by high concentrations of Mg 2+ , Na + , Ca 2+ , HCO 3 - , Fe Total , and low concentrations of Mn 2+ , NO 3 - and PO 4 3- . Groundwater samples are mainly Mg-Ca-HCO 3 and Na-Mg-Ca-HCO 3 types and Na-Mg-Ca-Cl-HCO 3 type of water is also found at some places. Based on Cl - and SO 4 2- concentrations groundwater is normal chloride and normal sulphate water, respectively. In terms of SAR and EC values water is excellent for irrigation purpose. The isotopic composition also suggests some segregation of groundwater from the different aquifers and indicates different ages of recharge. DOI: http://dx.doi. org/10.3329/jbas.v38i2. 21338 Journal of Bangladesh Academy of Sciences, Vol. 38, No. 2, 131-142, 2014
Internal structure of layer-by-layer adsorbed polyelectrolyte films : a neutron and X-ray reflectivity study

Ultrathin polymer films were physisorbed to surface-modified Si wafers by electrostatic deposition of polyelectrolytes from aqueous solutions. For the first it has been demonstrated that the preparation procedure, which involves repeated dipping of the substrate into solutions of polycations and polyanions in an alternating sequence, leads to the deposition of continuous molecular layers that form a polymer film with a well-defined supramolecular structure
Sorption of dissolved organic carbon by hydrous aluminum and iron oxides occurring at the confluence of deer creek with the Snake River, Summit County, Colorado

Organic solute sorption by hydrous iron and aluminum oxides was studied in an acidic, metal-enriched stream (the Snake River) at its confluence with a pristine stream (Deer Creek). From 1979 to 1986, typically 40% of the dissolved organic carbon (DOC) was removed from solution by sorption onto aluminum and iron oxides, which precipitate as the two streamwaters mix. Upstream DOC concentrations, which increase during snowmelt, were identified as the most significant variables in a multiple regression for determining the DOC concentration below the confluence, and the extent of Al and Fe precipitation was much less significant
High balanced ambipolar charge carrier mobility in benzodipyrrolidone conjugated polymers

A series of alternating donor–acceptor polymers, consisting of diphenyl-benzodipyrrolidone (BDP) and oligothiophene were synthesized and used in top-gate bottom-contact organic field-effect transistors. The BDP polymers exhibit ambipolar charge transport with high and balanced mobilities up to 0.21 cm2 V−1 s−1 for holes and 0.18 cm2 V−1 s−1 for electrons. Increasing the length of the oligothiophene reduces the electron mobility roughly by an order of magnitude per thiophene unit, but the hole mobility remains high. This behaviour is explained using DFT calculations by a strong localization of the electrons on the BDP units.
Intrinsic stress and stress gradients at the SiO2/Si interface in structures prepared by thermal oxidation of Si and subjected to rapid thermal annealing

This paper reports on a study of the intrinsic stress and strain in thin films of SiO2 prepared by the thermal oxidation of crystalline silicon. We focus on the relationship between the inhomogeneity of thin‐film properties and the thermal history of the oxide film, including both film growth and thermal annealing. We show that this film can be inhomogeneous in the sense that oxide formed initially at the silicon–silicon dioxide (Si/SiO2) interface has been annealed at the growth temperature for the time required for film growth, whereas newly formed oxide at the growth interface has not been annealed for any appreciable period. We demonstrate that thermal annealing cannot completely remove the thickness dependence in the strain induced by the mismatch between the molar volumes of silicon and silicon dioxide at the growth interface, subject to constraints introduced by the chemical bonding structure at that interface. Based on laser‐beam deflection and photoreflectance measurements, we show that there is .
Role of Mycorrhiza in a Wheat–Flax versus Canola–Flax Rotation: A Case Study

Early-season growth of flax (Linum usitatissimum L.) was reduced in the field following canola (Brassica napus L.) compared to rotation with wheat (Triticum aestivum L.). This effect was associated with reduced formation of arbuscular mycorrhizae in flax caused by rotation with canola. Greater uptake of copper (Cu), phosphorus (P), and zinc (Zn) was seen for flax after wheat. Mycorrhizal stimulation of uptake of these elements likely relates to their immobility in soil. The ratio of biomass of flax after wheat to flax after canola was 1.6. Corresponding ratios of nutrient uptake were 1.5 to 1.8 for Cu, P, and Zn but were between 1.2 and 1.4 for macronutrients other than P. These data illustrate the importance of consideration of a range of nutrients for concentration, uptake, and ratios of uptake among treatments to evaluate the impact of arbuscular mycorrhizae. Rotation of flax after canola should be avoided.
Correlation of the Rates of Solvolysis of Phenyl Fluorothionoformate

The specific rates of solvolysis of phenyl fluorothionoformate (PhOCSF, 1) have been determined in 22 pure and binary solvents at . The extended Grunwald-Winstein equation has been applied to the specific rates of solvolysis of 1 over the full range of solvents. The sensitivities (l = and m = ) toward the changes in solvent nucleophilicity and solvent ionizing power, and the values are similar to those previously observed for solvolyses of acyl haloformate esters, consistent with the addition step of an additionelimination pathway being rate-determining. The large negative values for the entropies of activation are consistent with the bimolecular nature of the proposed rate-determining step. The results are compared with those reported earlier for phenyl chloroformate and chlorothionoformate esters and mechanistic conclusions are drawn.
Corresponding states analysis of the critical points in binary solutions of room temperature ionic liquids

A systematic study of liquid–liquid phase transitions in mixtures of room temperature ionic liquids (RTIL) with nonionic solvents of different dielectric constant is presented. We report phase diagrams and the location of the critical points in the binary systems. The salts are 1-alkyl-3-methylimidazolium tetrafluoroborates and hexafluorophosphates with butyl-, hexyl-, octyl- side chains. The solvents are water, n-alcohols (n = 1 − 16), branched alcohols, and dialcohols. A corresponding state analysis of the data is carried out in terms of the variables of the restricted primitive model (RPM), which considers ionic fluids as equal-sized charged hard spheres in a dielectric continuum. The reduced critical temperatures are found to depend almost linearly on the dielectric constant of the solvent. The data of all investigated systems are represented by a master plot, which indicates a continuous crossover from a Coulomb driven phase transition, reasonably described by the RPM, towards a phase transition determined by hydrophobic interactions.
Six-dimensional ab initio potential energy surfaces for H3O+ and NH3: Approaching the subwave number accuracy for the inversion splittings

New potential energy surfaces are calculated for the hydronium ion using high-order coupled cluster ab initio methods. Large basis sets are used especially for the inversion part of the full surface. Electronic energies obtained with different correlation consistent basis sets are extrapolated to the infinite basis set limit. Core-valence and first order relativistic effects are also included. The influence of these two contributions and basis set sizes on both the inversion barrier height and equilibrium geometry are investigated thoroughly. The same methods are also adopted for ammonia in order to further improve a recently published surface [J. Chem. Phys. 118, 6358 (2003)]. The vibrational eigenvalues are calculated variationally both for the symmetric and asymmetric isotopomers using exact six-dimensional kinetic energy operators and successive basis set contractions. With the new surfaces, the mean absolute deviations obtained for all experimentally observed inversion splittings for different isotop.
Thin‐Layer Chromatography of Nucleotides

Thin-layer chromatography of nucleotides on DEAE- and ECTEOLA-cellulose is superior to the methods of seperation in use up to the present. Using dilute hydrochloric acid, and without a gradient elution technique, it is possinle to acheive a group seperation of monodi-, and tri-phosphates as well as subfractionation within these groups depending on the basicity of the nucleobases. Thin-layer chromatography is appreciably more sensitive than paper chromatography; 5×10−4 mole adenine neuclotides can be still be detected. The total quantity of material that can be chromatographed without tailing is greater in this procedure than that with paper chromatography; a mixture consisting of 1 μmole ATP and ADP per starting spot can be resolved with ease . Hence the procedure can also be applied for micro-scale preparative seperations . A mixtures of 10−2 μmole ADP and ATP, respectively, can be seperated completely in four to ten minutes.
Determination of the crystallographic orientation of cubic media to high resolution using optical harmonic generation

Using the tensorial characteristic of optical harmonic generation it is shown that the crystallographic orientation of centrosymmetric and noncentrosymmetric cubic media can be determined to within ±0.1°. As an illustration of the technique the orientation of vicinal GaAs(001) and Si(111) single‐crystal wafers is obtained using second‐ and third‐harmonic generation, respectively, with a continuously mode‐locked Ti:sapphire laser operating at 775 nm. Intensity measurements were taken as a function of the wafer azimuthal angle and are fit to a truncated Fourier series derived from a phenomenological theory.
Double Photoionization of Endohedrally Confined Atoms

We study the double electronic emission by photon impact from ground state of two-electron atoms in the center of a model spherical fullerene, which is described by a square-well shell. Cross-sections for different well depth are computed within a separable model for the final state, and a configuration interaction state for the initial one. Triple differential cross-sections show a strong dependence on the well depth and on the energy of the emitted electrons, due to the delocalization of the electrons in the initial state. The fullerene potential also allows higher angular momenta partial waves to be included in the process, which modifies the well-known two-lobe cross-section from isolated atom.
Correlation of Solubilities and Entrainer Effects for Fatty Acids and Higher Alcohols in Supercritical Carbon Dioxide Using SRK Equation of State with Association Model

Solubilities of fatty acids (myristic acid, palmitic acid and stearic acid) and higher alcohols (cetyl alcohol, stearyl alcohol and arachidyl alcohol) in supercritical CO2, and the entrainer effect (ethanol or octane) on their solubilities, are correlated by the Soave-Redlich-Kwong equation of state with an association model. It is assumed that the system consists of supercritical CO2, solute monomer, solute dimer, hydrogen bonding species between solute monomer and entrainer, and entrainer. The mole fractions of these species are determined by the equilibrium constants for dimerization of palmitic acid, and those for hydrogen bonding species between palmitic acid and ethanol obtained from FTIR spectroscopic study. The calculated results agreed with the experimental data.
Removal of boron from aqueous solution using magnesite and bentonite clay composite

AbstractThe removal of boron from industrial effluents using the composite was studied in batch equilibration technique. The effects of equilibration time, adsorbent dosage, concentration and pH on removal of boron were investigated. The experiments demonstrated that boron removal is optimum at 30 min of agitation, 1 g of dosage and 20 mg L−1 of ion concentration. Adsorption of boron by the composite was independent of pH. The adsorption data fitted well into both Langmuir adsorption isotherm and Freundlich adsorption isotherm hence proving monolayer and multilayer adsorption. The kinetic studies reported that the data favours pseudo-second-order reaction than first order hence proving chemisorption. Under optimized conditions, the composite was able to remove boron to below World Health Organization (WHO) water quality guidelines. Henceforth, it was concluded that this comparative study will be helpful for further application in the treatment of boron-contaminated water.
Control of the formation of rod-like ZnO mesocrystals and their photocatalytic properties

Mesocrystals usually assume properties differing from that of nanocrystals with the same compositions due to their unique morphologies and size region. In the work, a simple wet chemical procedure was developed for the preparation of mesocrystals consisting of ZnO nanoparticles. By simply mixing the aqueous solutions of zinc acetate [Zn(Ac)2], sodium hydroxide (NaOH), and tartaric acid (TA) at certain temperatures, composites of zinc hydroxide nanoparticles and tartaric acid, Zn(OH)2–TA, with rod-like morphology were obtained. After being annealed in air at certain temperatures, the mesocrystals composed of ZnO nanoparticles were generated, which inherited the rod-like morphology of the Zn(OH)2–TA composites. The chemical composition, crystalline structure and morphology of as-prepared ZnO mesocrystals were characterized using scanning electron microscopy, X-ray powder diffraction, FT-IR, and thermogravimetric analysis. Their photocatalytic properties were also investigated. It was illustrated that, in comparison with the individual ZnO nanoparticles, the ZnO mesocrystals show decent photocatalytic performance to the photodegradation of methyl orange and the photoreduction of Cr6+.
Monte Carlo simulation of micelle formation in block copolymer solutions

Short block copolymers in selective solvents (bad for A-block, good for B-block) are modeled by flexible bead-spring chains, where beads interact with short range Morse potentials of variable strength. It is shown that already very short chains (N A = N B = 2) exhibit a rather well-defined critical micelle concentration (cmc). The mass distribution of the micelles and their gyration tensor components as well as their internal structure are studied. It is shown that the relaxation time increases exponentially with the strength E AA of the attractive energy between the A-monomers, and thus frozen-in micelles of medium size are obtained when E AA is chosen too large. Our results are compared to studies of related but somewhat different models.