Miracle-dz/UniFAR-FTUs huggingface dataset:
MNDO parameterized hybrid SLG/SCF method as used for molecular modeling of Zn(II) complexes

The McWeeny's group functions technique is a natural way to introduce local description into quantum chemistry. It can also serve as a basis for constructing numerically effective computational schemes with almost linear scaling of computational costs with the size of a system. In this study, we apply it to the coordination compounds of Zn(II)-containing ligands with nitrogen and oxygen donor atoms. In these compounds, the electron group corresponding to the metal vacant 4s- and 4p-atomic orbitals (AOs) of the Zn 2 ion and its closest coordination sphere formed by the lone pairs (LP) located on the donor atoms naturally separates. This group, designated metal and lone pairs (MLP), is described by the SCF wave function within the hybrid scheme of strictly local geminals/self-consistent field (SLG/SCF). The SLC/ SCF scheme is based on the group function approach combining different descriptions for different electron groups: two-electron two-center bonds are described by geminals (SLG groups), while all the remaining electron groups are described by Slater determinants in the one-electron (SCF) approximation (SCF groups). The original MNDO Hamiltonian parameterization for the Zn atom is adjusted for correct description of geometry of the complexes. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem 106: 2268 -2280, 2006
Metal drift behavior in low dielectric constant organosiloxane polymer

Metal drift into a low dielectric constant (low κ) hybrid organosiloxane (OS) polymer has been investigated using metal/OS/SiO2/Si capacitors. Compared to Cu, Al gate metal capacitors showed larger flatband voltage shifts in the capacitance–voltage (C–V) curves upon bias temperature stressing (BTS). To elucidate the mechanism and source of this bias instability, further BTS experiments were performed with gate metals tantalum and platinum. It is suggested that all these metals, except Pt, drift into the dielectric and the extent of drift appears to be directly related to the metal’s tendency to oxidize. The calculations, assuming singly ionized metal species, show that the charges/cm2 entering the dielectric fall in the order Pt<Cu<Ta<Al. A mechanism is proposed linking the presence of oxygen in OS to the ionization of the metals, and consequent drift through the dielectric under applied electric fields.
Surface Modification of Natural Graphite by Phenolic Resin Carbon Coating for Improvement of Cyclic Performances in Lithium Ion Batteries

Natural graphite was coated with different concentrations of phenolic resin and methane solution. To obtain modified graphite, the coated natural graphite was further carbonized at a temperature of 1000°C for 1 h under a N2 stream after removing the solvent of methane. The surface morphology and microstructure of modified graphite were investigated with scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The computer-controlled constant-current cycler investigated charge and discharge performances. Results showed that the phenolic resin carbon with disordered structure formed on the surface of graphite could protect the graphite from exfoliation and improve its cyclic performances successfully. The reversible capacity and coulombic efficiencies of modified graphite were higher than that of natural graphite during charge and discharge cycling tests at a rate of 50 mA ˙ g-1. It is confirmed that modified graphite has an advantage for an application of high power density lithium ion battery.
Nonlinear femtosecond laser processing of alkylsiloxane monolayers on surface-oxidized silicon substrates

Femtosecond laser patterning of octadecylsiloxane monolayers on surface-oxidized silicon substrates via single-pulse processing at λ=800nm, τ<30fs, and ambient conditions has been investigated. Depending on the laser pulse fluence, local irradiation results in circular spots of distinct size and morphology. At high fluences, a particular rich complexity of distinct surface morphologies is observed including hole, rim, and ripple formation, and a faint boundary area where monolayer decomposition sets in. At low fluences, subwavelength patterning of the organic monolayer is feasible. In particular, at a 1∕e laser spot diameter of 1. 3μm, surface spots with a width down to 300nm are fabricated. Selective processing of the organic monolayer, though, is restricted to a very narrow range of fluences between 1.1 and 1.2J∕cm2. A significantly larger parameter range for selective processing is anticipated in the case of functional monolayers that incorporate aromatic groups. Promising perspectives in femtosecond laser processing of organic monolayers are discussed.Femtosecond laser patterning of octadecylsiloxane monolayers on surface-oxidized silicon substrates via single-pulse processing at λ=800nm, τ<30fs, and ambient conditions has been investigated. Depending on the laser pulse fluence, local irradiation results in circular spots of distinct size and morphology. At high fluences, a particular rich complexity of distinct surface morphologies is observed including hole, rim, and ripple formation, and a faint boundary area where monolayer decomposition sets in. At low fluences, subwavelength patterning of the organic monolayer is feasible. In particular, at a 1∕e laser spot diameter of 1. 3μm, surface spots with a width down to 300nm are fabricated. Selective processing of the organic monolayer, though, is restricted to a very narrow range of fluences between 1.1 and 1.2J∕cm2. A significantly larger parameter range for selective processing is anticipated in the case of functional monolayers that incorporate aromatic groups. Promising perspectives in femtosecond la.
Highly conducting iodine derivatives of polyacetylene: Raman, XPS and x‐ray diffraction studies

Polyacetylene film and bulk samples were prepared by polymerization of acetylene in the presence of a μ‐ (η1:η5‐cyclopentadienyl) ‐tris (η‐cyclopentadienyl) dititanium (Ti–Ti) catalyst in hexane. Conducting films (σR.T.∼25 Ω−1⋅cm−1), or bulk polymer samples (σR.T.∼1 Ω−1⋅ cm−1) were prepared by treatment of the nascent polymer with solutions of iodine in hexane. Raman, x‐ray photoelectron, and x‐ray diffraction techniques were used to characterize these polyacetylene‐iodine derivatives. The measurements are consistent with the presence of iodine in two different forms, I3− and possibly I5−. Although the concentration of the iodine varied in different samples (40%–70% by weight), in all cases the amount of the second species decreases irreversibly upon thermal annealing or the application of high mechanical stresses. X‐ray diffraction measurements suggest that iodine species intercalate in sheets parallel to a close packed plane of the polyacetylene. Valence band x‐ray photoelectron spectroscopy measurement.
Simulation of layered double hydroxide intercalates

A Williamson ether reaction of hydroquinone with (S)2-methylbutyl p toluenesulfonate gives 1,4-bis[(S)-2-methylbutoxy]benzene, 1, in 74 % yield after column chromatography. Subsequent chloromethylation of 1 with HC1 and 36 % formaldehyde in 1,4-dioxane yields pure 1,4-bis (chloromethy1)2,5-bis[(S)-2-methyIhutoxy]henzene, 2. Polymerization of 2 is carried out with K'BuO in dry refluxing 1,4-dioxaue for 5 h. The polymerization is stopped by addition of acetic acid and BMB-PPV is isolated by filtration of the reaction mixture, washing. and drying.
High‐Temperature Wetting of Sapphire by Aluminum

Sessile drop studies of molten aluminum on single-crystal sapphire substrates were conducted to investigate the effects of atmosphere on contact angle, substrate reactions, and interfacial crystal growth. Unlike previous investigations performed briefly in a vacuum environment in a temperature range within 600°C of the aluminum melting point, these experiments were conducted at higher temperatures (1200° to 1600°C) and at 1-atm total pressure over longer experimental times to more closely approach equilibrium conditions. A continuously flowing buffered gas system utilizing high-purity metered mixtures of hydrogen and helium in combination with a thoria ceramic electrolyte sensor were employed to achieve variations of the oxygen partial pressure from 10−19 to 10−15 atm while continuously maintaining the total pressure at 1 atm. At constant temperature, it was found that neither the oxygen partial pressure nor the crystallographic orientation of the sapphire substrate had a significant effect on the observed contact angles. A continuous decrease of acute contact angles and a single reaction ring characterized the 8-h experiments without the alternating spreading and contracting behavior repeatedly reported in the literature. This phenomenon can be attributed to the lower rate of metal evaporation and interfacial reaction at the higher total gas pressure and yet extremely low oxygen partial pressure of these experiments. Profilometric analysis of sapphire substrates subsequent to the removal of the quenched sessile drops indicates a reduction in metal–solid interaction due to the closer approach to equilibrium than in previous studies. An epitaxial orientation with respect to the substrate was observed in α-alumina crystallite formation at the metal–ceramic interface. Experimental evidence suggests that it was formed by a nucleation and growth process during the cooling period.
Raman microspectroscopic evidence that dry‐fixing preserves the temporal pattern of non‐specific differentiation in live human embryonic stem cells

Raman microspectroscopy allows the classification of populations of human embryonic stem cells (hESCs) in different stages of differentiation based on the relative intensities of certain amino acid and nucleic acid bands. Here, we report the results of a comparative study of the Raman spectra of live cells versus cells killed and fixed by rapid desiccation, focusing on the ratio of intensities at 757 cm−1 (tryptophan) and 784 cm−1 (DNA and RNA). We observe that the same temporal pattern emerges over a 3-week time course in both sample types. This suggests that prolonged observations of dry-fixed cells can yield high signal-to-noise chemical images that cannot be obtained from colonies of living cells where the time scale of significant biological changes are comparable to the time scale of the measurement. This permits, for example, comparison of the spatial distributions of cells at different stages of differentiation within the same colonies. Copyright © 2010 John Wiley & Sons, Ltd.
Electrospinning of Collagen Type II: A Feasibility Study

Collagen is the natural scaffolding found in all tissues and has been explored extensively for use as a tissue engineering scaffold with limited success. In this feasibility study, the electrospinning of collagen type II and subsequent chondrocyte seeding was investigated for potential use in cartilage tissue engineering. The electrospinning process utilized lyophilized, chicken sternal cartilage collagen type II suspended in 1,1,1,3,3,3 hexaflouro-2-propanol and demonstrated that collagen type II could be electrospun to form nonwoven fibrous mats composed of type II fibers that ranged from 110 nm to 1. 8μm in diameter. The fiber diameter was dependant on the type II concentration in solution with a higher concentration producing the larger diameters. The preliminary chondrocyte seeding study demonstrated that electrospun collagen type II scaffolds support cell growth and are readily infiltrated. In conclusion, the feasibility of collagen type II electrospinning has been demonstrated and the novel scaffolds produced are composed of nano- to micron-scale fiber diameters that have been shown to be compatible with chondrocytes.
Highly stable aprotic ionic-liquid doped anhydrous proton-conducting polymer electrolyte membrane for high-temperature applications

Protic ionic-liquid (IL) based polymer electrolyte membranes (PEMs) have been reported for high-temperature fuel cell applications under anhydrous condition. Herein, we report aprotic IL (1-ethyl-3-methylimidazolium ethyl sulfate (EMIES)) and sulfonated poly(ether ether ketone) (SPEEK) based PEMs for fuel cell application under anhydrous condition. Liberated protons from –SO3H groups (SPEEK) due to ionic interaction with EMIES, were responsible for high conductivity under anhydrous conditions. High ionic interaction between the EMIES and SPEEK led to homogeneous mixing. Prepared SPEEK–IL-70 PEM exhibited 0.57 mS cm−1 conductivity (conductivity of EMIES: 3.445 mS cm−1 at room temperature), which was dramatically increased to 18.94 mS cm−1 at 150 °C under anhydrous condition. This enhancement in conductivity was explained due to the well-connected proton conducting channels formed in the polymer matrix because of good miscibility and interaction with EMIES. High stability and good conductivity of SPEEK–IL composite membranes demonstrated their potential application for high-temperature applications.
Probing Dynamics of Water Mass Transfer in Organic Porous Photocatalyst Water-Splitting Materials by Neutron Spectroscopy

The quest for efficient and economically accessible cleaner methods to develop sustainable carbon-free energy sources induced a keen interest in the production of hydrogen fuel. This can be achieved via the water-splitting process and by exploiting solar energy. However, the use of adequate photocatalysts is required to reach this goal. Covalent triazine-based frameworks (CTFs) are potential target photocatalysts for water splitting. Both electronic and structural characteristics of CTFs, particularly energy levels, optical band gaps, and porosities are directly relevant to water splitting and can be engineered through chemical design. Porosity can, in principle, be beneficial to water splitting by providing a larger surface area for the catalytic reactions to take place. However, porosity can also affect both charge transport within the photocatalyst and mass transfer of both reactants and products, thus impacting the overall kinetics of the reaction. Here, we focus on the link between chemical design and water (reactant) mass transfer, which plays a key role in the water uptake process and the subsequent hydrogen generation in practice. We use neutron spectroscopy to study the mass transfer of water in two porous CTFs, CTF-CN and CTF-2, that differ in the polarity of their struts. Quasi-elastic neutron scattering is used to quantify the amount of bound water and the translational diffusion of water. Inelastic neutron scattering measurements complement the quasi-elastic neutron scattering study and provide insights into the softness of the CTF structures and the changes in librational degrees of freedom of water in the porous CTFs. We show that two different types of interaction between water and CTFs take place in CTF-CN and CTF-2. CTF-CN exhibits a smaller surface area and lower water uptake due to its softer structure than CTF-2. However, the polar cyano group interacts locally with water leading to a large amount of bound water and a strong rearrangement of the water hydration monolayer, while water diffusion in CTF-2 is principally impacted by microporosity. The current study leads to new insights into the structure-dynamics–property relationship of CTF photocatalysts that pave the road for a better understanding of the guest–host interaction on the basis of water-splitting applications.
Self-assembled quantum-dot molecules by molecular-beam epitaxy

Self-assembled InAs quantum-dot (QD) molecules having high dot density and aligned dot set structure, which is defined by nanotemplates, were realized by thin capping and regrowth technique in a molecular-beam epitaxy process. Thin capping of GaAs on InAs QDs leads to the creation of nanoholes having a camel-like nanostructure due to anisotropic strain fields along the [11¯0] crystallographic direction and anisotropic surface diffusion accompanying the QD collapse. Regrowth of InAs QDs on the nanohole templates initially results in the formation of QDs with good size uniformity in the middle of features with the shape of propeller blades. This takes place at the regrowth thickness of 0.6 monolayer (ML). The strain at propellers’ edge starts to play its role, creating sets of quantum dots surrounding the initial and centered dots at the regrowth thickness of 1.2 ML. The elongated configuration of propellers’ blades defines the pattern of QD sets having five to six dots on each side. The dot density of the .
Hierarchical Variational Auto-Encoding for Unsupervised Domain Generalization

We address the task of domain generalization, where the goal is to train a predictive model such that it is able to generalize to a new, previously unseen domain. We choose a hierarchical generative approach within the framework of variational autoencoders and propose a domain-unsupervised algorithm that is able to generalize to new domains without domain supervision. We show that our method is able to learn representations that disentangle domain-specific information from class-label specific information even in complex settings where domain structure is not observed during training. Our interpretable method outperforms previously proposed generative algorithms for domain generalization as well as other non-generative state-of-the-art approaches in several hierarchical domain settings including sequential overlapped near continuous domain shift. It also achieves competitive performance on the standard domain generalization benchmark dataset PACS compared to state-of-the-art approaches which rely on observing domain-specific information during training, as well as another domain unsupervised method. Additionally, we proposed model selection purely based on Evidence Lower Bound (ELBO) and also proposed weak domain supervision where implicit domain information can be added into the algorithm.
Improvements in Digestion Protocols for Trace Element and Isotope Determinations in Stream and Lake Sediment Reference Materials (JSd‐1, JSd‐2, JSd‐3, JLk‐1 and LKSD‐1)

Total dissolution is a critical step in geochemical analysis. Despite the number of published protocols, this issue still draws attention for sediment samples, which are particularly difficult to dissolve due to the common occurrence and high abundance of refractory phases such as zircon. We present tests of different chemical digestion procedures carried out on reference materials (RM) of stream (JSd‐1, JSd‐2 and JSd‐3) and lake (JLk‐1 and LKSD‐1) sediments from the Geological Survey of Japan (GSJ) and the Canadian Certified Reference Material Programme (CCRPM). We demonstrate that the fusion technique is not appropriate for our studies as not all elements of interest were recovered and blank levels were too high to permit further Sr and Pb isotopic composition measurements. Similarly, conventional HF+HNO3 dissolution methods were not efficient enough for detrital samples. Our preferred method involved using high pressure Teflon® vessel bombs in association with HClO4. This protocol ensured a complete dissolution of the powder, as well as a complete recovery of trace elements. Moreover, blank levels were sufficiently low that Sr or Pb isotope compositions could be measured from the same mother solution. We also tested the homogeneity of RM powders by performing tests on various amount of powder.
Kinetic Parameters of Binary Iron/Oxidant Pyrolants

The thermal properties of pyrotechnic mixtures containing iron powder as fuel and KNO3, KClO3, and KClO4 as oxidants are reported. The thermogravimetry–differential thermal analysis results for pure components and corresponding pyrotechnic mixtures revealed that the melting point, decomposition temperature, and rate of oxygen releasing of the oxidants have dominant effects on ignition reaction of the pyrotechnic mixtures. The apparent activation energy and activation parameters for the combustion processes were evaluated from the differential scanning calorimetry experiments. Based on the ignition temperatures obtained and the resulting kinetic data, the thermal reactivity of the pyrotechnic mixtures was found to decrease as in the order Fe + KClO3 > Fe + KNO3 > Fe + KClO4.
Fabrication of a Modified Electrode Based on Fe3O4-Graphene Oxide Hybrid Composite: Applying to Simultaneous Determination of Adenine and Guanine in DNA

A Fe3O4-graphene oxide hybrid composite (Fe3O4GO) was synthesized and used to construct a novel electrochemical sensor for the simultaneous detection of adenine and guanine. The Fe3O4GO based electrochemical sensor exhibits linear ranges of 0.05–25 μM and 0.05–25 μM with detection limits of 4 nM and 3 nM for adenine and guanine, respectively. This method was applied in the determination of guanine and adenine in many samples with satisfying results. The value of (G+C)/(A+T) in DNA was calculated to be 0.7536. The sensor exhibits some advantages, such as rapidity, good reproducibility and long-term stability.
On the Active Surface State of Nickel‐Ceria Solid Oxide Fuel Cell Anodes During Methane Electrooxidation

Solid oxide fuel cells (SOFCs) have grown in recognition as a viable technology able to convert chemical energy directly into electricity, with higher efficiencies than conventional thermal engines. Direct feeding of the SOFCs anode with hydrocarbons from fossil or renewable sources, appears more attractive compared to the use of hydrogen as a fuel. The addition of mixed oxide‐ion/electron conductors, like gadolinium‐doped ceria (GDC), to commonly used nickel‐based anodes is a well–known strategy that significantly enhances the performance of the SOFCs. Here we provide in situ experimental evidence of the active surface oxidation state and composition of Ni/GDC anodes during methane electroxidation using realistic solid oxide electrode assemblies. Ambient pressure X‐ray photoelectron and near edge X‐ray absorption fine structure spectroscopies (APPES and NEXAFS respectively) combined with on line electrical and gas phase measurements, were used to directly associate the surface state and the electrocatalytic performance of Ni/GDC anodes working at intermediate temperatures (700°C). A reduced anode surface (Ce3+ and Ni), with an optimum Ni to Ce surface composition, were found to be the most favorable configuration for maximum cell currents. Experimental results are rationalized on the basis of first principles calculations, proposing a detailed mechanism of the cell function.
The interplay of structure and dynamics in the melting of small clusters

Extensive classical simulations of the melting–freezing transition of small clusters (N=7–33) of rare gas atoms have been performed in which quenching by steepest descent has been coupled to isoergic molecular dynamics. A mechanistic description of the phase change is given in terms of the local potential minima accessed in the transition region and the isomerization pathways for and the frequencies of interwell passages. All of the small clusters, at energies low in the transition range of energy, exhibit some separation (by factors of approximately 5 to 60) of the short time scale for motions about the various potential minima and the longer time scale separating interwell passages. The onset of diffusion is marked by passages over saddles linking the minima. Fully liquid‐like behavior is observed for all the clusters when the time scale separation for the motions no longer exists. The coexistence and magic number phenomena observed in previous simulations are explained in terms of the kinds of potentia.
New Phenylnickel‐(2‐phosphinobenzenesulfonate) Triphenylphosphine Complexes as Highly Active Ethylene Polymerization Catalysts

The first examples of SHOP type nickel(II) catalysts bearing new phosphine chelate ligands comprised of a coordinating sulfonate functional group have been synthesized and structurally characterized. These catalysts show high activities in the polymerization of ethylene and can even be used without phosphine scavengers. Polyethylenes with 15–25 branches per 1000 carbon atoms are produced from ethylene monomer alone.