Miracle-dz/UniFAR-FTUs huggingface dataset:
Towards neutron scattering experiments with sub- millisecond time resolution

Neutron scattering techniques offer several unique opportunities in materials research. However, most neutron scattering experiments suffer from the limited flux available at current facilities. This limitation becomes even more severe if time-resolved or kinetic experiments are performed. A new method has been developed which overcomes these limitations when a reversible process is studied, without any compromise on resolution or beam intensity. It is demonstrated that, by recording in absolute time the neutron detector events linked to an excitation, information can be resolved on sub-millisecond timescales. Specifically, the concept of the method is demonstrated by neutron reflectivity measurements in time-of-flight mode at the Liquids Reflectometer located at the Spallation Neutron Source, Oak Ridge National Laboratory, Tennessee, USA, combined with in situ rheometry. The opportunities and limitations of this new technique are evaluated by investigations of a micellar polymer solution offering excellent scattering contrast combined with high sensitivity to shear.
Satellite structure in the photoelectron spectra of transition-metal compounds

Abstract The electronic structure of high-spin CrCl3 and CrBr3 compounds has been investigated by means of X-ray photoelectron spectroscopy. Satellite features have been observed in the valence-band region and in Cr2p, Cr3s and Cr3p core-level spectra. Photoemission spectra have been analysed in terms of a simple cluster model, leading to estimates of the Coulomb correlation energy, charge transfer energy and hybridization strength. Satellites can be explained in general by a charge-transfer process, if the effective hybridization energy T eff (3.6-3.7 eV) is large enough. However, in the case of Cr3s core-level spectra, the main emission is assigned to unscreened multiplet transitions and final-state screening effects do not seem to contribute to the satellite structure.
Dispersion Polymerization of Methyl Methacrylate in Supercritical CO2

A series of graft copolymers, poly(methyl methacrylate-co-hydroxyethyl methacrylate)-g-poly(perfluoropropylene oxide), was synthesized for application as stabilizers in dispersion polymerization of methyl methacrylate in supercritical carbon dioxide. The backbone, poly(methyl methacrylate-co-hydroxyethyl methacrylate), is effectively insoluble in carbon dioxide and the grafted chains, poly(perfluoropropylene oxide), are completely miscible in carbon dioxide at moderate pressures. The effect of molecular architecture on polymerization rate and PMMA particle size was evaluated by varying the molecular weight of the anchor group (backbone of the copolymer), molecular weight of the CO2-soluble graft chain, and graft chain density. The efficiency of the graft copolymers as dispersants was demonstrated as micron-size polymer beads of molecular weight greater than 100 000 were produced. The results showed that a careful balance between anchor group size (backbone length) and amount of soluble component (either g.
Modified independent component analysis and Bayesian network-based two-stage fault diagnosis of process operations

Statistical fault detection techniques are able to detect fault and diagnose root-cause(s) from the monitored process variables. For complex process operations, it is not feasible to screen all the process variables due to monitoring cost and flooding of alarms. Thus, if a fault is originated from a process variable that is not monitored, conventional statistical techniques are incapable of locating the true root-cause. To relax this limitation, a two-stage fault diagnosis technique is proposed for process operations. In the first-stage, the modified independent component analysis is used for fault detection and to identify the faulty monitored variable. In the second-stage, a Bayesian Network model is constructed considering the process variables and their dependence obtained from the process flow diagram. Evidence is then generated at the network node corresponding to the faulty variable identified in the first-stage. Subsequently, the network is updated and analyzed using deductive and abductive reason.
Nano-Raman spectroscopy with side-illumination optics

We describe an apertureless near-field Raman spectroscopy setup that has successfully produced substantial enhancements for a wide variety of samples and achieved a high contrast. The tremendous potential of tip-enhanced Raman spectroscopy (TERS) for nanoscale chemical characterization has been demonstrated by various groups by measuring organic dyes, biological molecules, single-walled carbon nanotubes and silicon. Keys to rapid advances in the application of TERS to pressing scientific problems include the optimization of the method to achieve greater reproducibility and greater enhancement factors if possible, but more importantly, greater imaging contrast. Using a side-illumination geometry, we demonstrate reproducible enhancements of the Raman signal per volume on the order of 103–104 using silver- and gold-coated tips on various molecular, polymeric and semiconducting materials as well as on carbon nanotubes. We have experimentally verified localization of the enhancement to a depth of ∼20 nm. Most importantly, optimization of the polarization geometry makes possible a contrast between the near-field and far-field signals of 900% in the case of silicon—a level that makes the technique attractive for various applications. Copyright © 2005 John Wiley & Sons, Ltd.
Chromatographic Separation of Strontium (II) from a Nitric Acid Solution Containing some Typically Simulated Elements by a Novel Silica‐Based TODGA Impregnated Polymeric Composite in the MAREC Process

Abstract A new kind of macroporous silica‐based N,N,N′,N′‐tetraoctyl‐3‐oxapentane‐1,5‐diamide (TODGA) chelating polymeric adsorption material (TODGA/SiO2‐P) was developed and synthesized by impregnating TODGA molecules into the pores of ∼50 µm SiO2‐P particles to separate strontium effectively from high‐level liquid waste (HLLW). The adsorption of some typically simulated elements Na(I), K(I), Cs(I), Rb(I), Sr(II), Ba(II), and Ru(III) towards TODGA/SiO2‐P adsorbent was investigated by examining the influence of contact time and HNO3 concentration. It was found that with an increase in the HNO3 concentration, the adsorption of Sr(II) onto TODGA/SiO2‐P adsorbent increased quickly from 0.5 M to 2.0 HNO3 and then decreased. TODGA/SiO2‐P exhibited excellent adsorption ability and selectivity for Sr(II) over all of the tested elements, which showed almost no adsorption. Based on the batch experiments, the separation of Sr(II) from a 2.0 M HNO3 solution containing ∼5×10−3 M of the simulated elements was performed by TODGA/SiO2‐P packed column at 25°C and 50°C, respectively. Cs(I), K(I), Ru(III), Ba(III), Rb(I), and Na(I) were found to facilely elute out column and flow into effluent along with feed solution and 2.0 M HNO3 because of no adsorption. Sr(II) adsorbed towards TODGA/SiO2‐P was desorbed sufficiently by distilled water and separated completely from the simulated elements. Its recovery percentage was 100.2% at 25°C and 99.7% at 50°C. Furthermore, the leakage behavior of TODGA from its silica‐based adsorbent was investigated. It was found that the quantity of TODGA leaked was basically equivalent to its solubility in the corresponding HNO3 solution.
Controllable Synthesis of Shuttle‐Shaped Ceria and Its Catalytic Properties for CO Oxidation

Shuttle-shaped ceria was obtained in a high yield via a surfactant octadecylamine and urea assisted solvothermal process. The crystalline structure and morphology were characterized with powder X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM). Preliminary catalytic measurement shows that the shuttle-shaped CeO(2) exhibits an enhanced activity for CO oxidation, which may be attributed to its higher porosity and more oxygen vacancies. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Theorizing on Arab Family Business

The article identifies the distinct characteristics of family businesses in the Arab World and argues that management practice of Arab Family Businesses(AFB) differs significantly from previous testaments of international family business practices. It is also explained that constructs like Namus, Wasta, Diwan, and Asabiyya are vital to distinguish between the international understanding of Family Businesses and Arab Family Businesses. The differentiating factors of Arab clans are precisely the ones that provide competitive advantages and security from competitive pressures. Concepts of knowledge reservoir, social networking, emotional and symbolic capital have a significant influence on family business practice in the Arab world. The main contribution of this article is to develop propositions as a way to both simplify and clarify the key constructs(Namus, Wasta, Diwan & Asabiyyah) in a middle range theory(Arab family business) with the approach of modeling-as-theorizing and to define Arab Family Business.
Diagonalisation d'une classe d'hamiltoniens de spin

On diagonalise une classe a 2 N parametres d'hamiltoniens quadratiques dependant de N spins de grandeur arbitraire. Diverses extensions et applications sont donnees, en particulier celle de l'oscillateur couple a une collection de systemes independants a deux niveaux.
Contrast in transmission X-ray diffraction topographs of growth defects in the core of SrLaGaO4 single crystals

Defects in the core of SrLaGaO4 single crystals, grown by the Czochralski method using a [001]-oriented seed, were studied by transmission X-ray diffraction projection topography. Topographs were taken with radiation from a laboratory source and with high-energy radiation available at the ESRF beamline ID19 in Grenoble. The contrast of the investigated defect images was analysed for various diffraction vectors g and for various values of the product μ0t (μ0 is the linear absorption coefficient and t the crystal thickness). This allowed the contrast formation to be studied as a function of absorption. The results of the analysis confirm the model of crystal lattice deformation around rod-like volume defects in SrLaGaO4 crystals.
Noble Gas Separation by Adsorptive Phenomena in Mass Spectrometry

For precise measurements of noble gases with a mass spectrometer, we need to separate each noble gas by adsorptive phenomena at low temperatures. We made adsorptive experiments for Ar, Kr, and Xe using a cold trap containing a sintered stainless steel filter element. In this paper, we applied a simple model to our experimental observations in order to better understand the adsorptive phenomena on the adsorbent, and obtained the conditions for more efficient separation of individual noble gas. The results suggest that the adsorption curves shift to a higher temperature when we release gas in a smaller volume of the extraction line. This temperature shift is larger for a noble gas with a higher mass. Therefore, small volume of preparation line is suitable for the clear separation of noble gases. It is also shown that the adsorption curve depends on the pressure of gases when the total number of gas atoms in the line is not negligible compared to the maximum number of atoms being adsorbed.
Glutaraldehyde in bio-catalysts design: a useful crosslinker and a versatile tool in enzyme immobilization

Glutaraldehyde is one of the most widely used reagents in the design of biocatalysts. It is a powerful crosslinker, able to react with itself, with the advantages that this may bring forth. In this review, we intend to give a general vision of its potential and the precautions that must be taken when using this effective reagent. First, the chemistry of the glutaraldehyde/amino reaction will be commented upon. This reaction is still not fully clarified, but it seems to be based on the formation of 6-membered heterocycles formed by 5 C and one O. Then, we will discuss the production of intra- and inter-molecular enzyme crosslinks (increasing enzyme rigidity or preventing subunit dissociation in multimeric enzymes). Special emphasis will be placed on the preparation of cross-linked enzyme aggregates (CLEAs), mainly in enzymes that have low density of surface reactive groups and, therefore, may be problematic to obtain a final solid catalyst. Next, we will comment on the uses of glutaraldehyde in enzymes previously immobilized on supports. First, the treatment of enzymes immobilized on supports that cannot react with glutaraldehyde (only inter and intramolecular cross-linkings will be possible) to prevent enzyme leakage and obtain some enzyme stabilization via cross-linking. Second, the cross-linking of enzymes adsorbed on aminated supports, where together with other reactions enzyme/support crosslinking is also possible; the enzyme is incorporated into the support. Finally, we will present the use of aminated supports preactivated with glutaraldehyde. Optimal glutaraldehyde modifications will be discussed in each specific case (one or two glutaraldehyde molecules for amino group in the support and/or the protein). Using preactivated supports, the heterofunctional nature of the supports will be highlighted, with the drawbacks and advantages that the heterofunctionality may have. Particular attention will be paid to the control of the first event that causes the immobilization depending on the experimental conditions to alter the enzyme orientation regarding the support surface. Thus, glutaraldehyde, an apparently old fashioned reactive, remains the most widely used and with broadest application possibilities among the compounds used for the design of biocatalyst.
High performance and negative temperature coefficient of low temperature hydrogen gas sensors using palladium decorated tungsten oxide

Gas sensors based on a noble metal–semiconductor are widely used, and they show a positive temperature response to hydrogen below 400 °C. In this study, a catalytically activated hydrogen sensor is obtained based on Pd decorated WO3 nanoplates constructed by a solvothermal method. An insight into the role of Pd catalyst in the outstanding performance is provided by comparing the sensing properties of this sensor with those of a traditional one made from the same pristine WO3. The pure WO3 sensor exhibits poor selectivity and low sensitivity to hydrogen. In contrast, the observed response of the as-produced sensor is up to 843 at a low operating temperature of 80 °C; the response value is even greater than that of WO3 sensors at high temperatures (250–400 °C). In addition, the Pd-loaded WO3 sensors show excellent selectivity towards H2 in comparison to other common gases (CH4, C3H6O, C2H6, C3H8O and NH3). The significantly improved performance is thoroughly explained in terms of the adsorption–desorption mechanism and chemical kinetics theories. Furthermore, an interfacial model demonstrated in this report indicates that the interfacial barrier between WO3 nanoparticles can be a novel effect for excellent gas sensing performance.
Kritischer Koeffizient, Dichte des gesättigten Dampfes und Verdampfungswärme. Untersuchungen über eine Erweiterung des Theorems der übereinstimmenden Zustände. Teil III

Nach dem Theorem der ubereinstimmenden Zustande in seiner erweiterten Fassung besteht eine eindeutige Beziehung zwischen dem kritischen Koeffizienten und dem kritischen Parameter, wofur eine der Erfahrung angepaste Gleichung angegeben wird. Ebenso werden Tabellen aufgestellt, die die Bestimmung des Kompressibilitatsfaktors (der die Abweichungen des gesattigten Dampfes vom Zustand des idealen Gases angibt) und der durch die kritische Temperatur dividierten molaren Verdampfungswarme in Abhangigkeit von dem kritischen Parameter und der reduzierten Temperatur ermoglichen. Die Regeln von Cederberg und Hildebrandt zur Berechnung der Verdampfungsentropie werden vom Standpunkt des erweiterten Korrespondenzprinzips aus erortert und verbessert bzw. widerlegt. Im Anschlus an eine einfache Formel fur die Verdampfungswarme der Flussigkeit am absoluten Nullpunkt wird auf die Bedeutung der Einfuhrung des kritischen Parameters hingewiesen.
Importance of Intersystem Crossing in the S(3P, 1D) + H2 → SH + H Reaction†

A “mixed” representation approach in conjunction with a trajectory surface-hopping method is used to study intersystem crossing effects in the S + H2 reaction. These calculations are based on high-quality potential surfaces that we have determined for the two lowest triplet states of SH2 and globally determined spin−orbit coupling matrix elements that are obtained from CASSCF calculations. A previously determined surface for the lowest singlet state (Ho, T.-S.; Hollebeek, T.; Rabitz, H.; Chao, S. D.; Skodje, R. T.; Zyubin, A. S.; Mebel, A. M. J. Chem. Phys. 2002, 116, 4124) is also used. We find that in contrast to the O(3P) + H2 reaction, which we studied previously at the same level, there is significant intersystem crossing in the S(3P) + H2 reaction. In particular, for the reaction starting from triplet S + H2 close to the threshold, the dominant mechanism involves intersystem crossing to the singlet state prior to encountering the triplet barrier, and as a result, the thermal rate constant at low tem.
Synthesis and Characterization of Poly(methyl methacrylate)-b-Polystyrene/TiO2 Nanocomposites Via Reversible Addition-Fragmentation Chain Transfer Polymerization

A diblock copolymer, poly(methyl methacrylate)-b-polystyrene (PMMA-b-PS), was grafted onto the surface of nano-titania (nano-TiO2) successfully via reversible addition-fragmentation chain transfer (RAFT) polymerization. The surface of TiO2 nanoparticles was modified initially by attaching dithioester groups to the surface using silane coupling agent 3-(chloropropyl)triethoxy silane and sodium ethyl xanthate. The polymerization of methyl methacrylate and styrene were then initiated and propagated on the TiO2 surface by RAFT polymerization. The resulting composite nanoparticles were characterized by means of XPS, FT-IR, 1H NMR and TGA. The results confirmed the successful grafting of poly(methyl methacrylate) (PMMA) and diblock copolymer chains onto the surface of TiO2. The amount of PMMA grafted onto the TiO2 surface increased with the polymerization time. Moreover, the kinetic studies revealed that the ln([M]0/[M]), where [M]0 is the initial and [M] is the time dependent monomer concentrations, increased linearly with the polymerization time, indicating the living characteristics of the RAFT polymerization.
Comments on the Nucleation Theorem

Abstract A critical analysis of the nucleation theorem in its different formulations is presented. A new formulation of the nucleation theorem, mathematically widely equivalent to the form given by Oxtoby and Kashchiev in 1994, is developed. This formulation is, however, more easily applicable to the interpretation of experimental results as compared with the original expressions given by Kashchiev and Oxtoby. It can be utilized straightforwardly also in cases where the original version cannot be employed and allows, in addition, a variety of further theoretical developments. It is shown, moreover, first in the framework of Gibbs' theory of heterogeneous systems that the nucleation theorem holds not only for critical clusters but for clusters of arbitrary sizes as well. The new formulation of the nucleation theorem is applied then to the analysis of different cases of phase formation. It is demonstrated, as a first application, that the original formulation of the nucleation theorem by D. Kashchiev (J. Chem. Phys.76, 5098 (1982)) can be extended to multicomponent systems as well. The conditions of validity of this particular formulation are discussed both for the original version (developed for one-component systems) and the generalization to multicomponent systems considered here. It turns out that the original formulation of the nucleation theorem is strictly valid only for incompressible cluster phases (i.e., for systems, strictly speaking, nonexistent in nature). Approximately, it may be employed for real systems as well but only in the limit of moderate supersaturations. As additional illustrations, the new general formulation of the nucleation theorem is applied then to different special cases of interest, analyzed and not analyzed before. A comparison with previous studies on similar topics is made. It is shown further that an alternative thermodynamic derivation of the nucleation theorem both for clusters of critical as well as for arbitrary sizes can be given at certain specified conditions based on the van der Waals approach to the description of heterogeneous systems. Finally, the limits of validity of the nucleation theorem are analyzed with respect to its applicability to real systems; i.e., the problem is discussed to what extent the nucleation theorem may give an adequate description of properties of critical clusters determining the nucleation process in real systems or in computer models of nucleation phenomena.
The collapse transition of semiflexible polymers. A Monte Carlo simulation of a model system

Monte Carlo simulations have been performed on a diamond lattice model of semiflexible polymers for a range of flexibilities and a range of chain lengths from 50 to 800 segments. The model includes both repulsive (excluded volume) and attractive segment–segment interactions. It is shown that the polymers group into two classes, ‘‘flexible’’ and ‘‘stiff. ’’ The flexible polymers exhibit decreasing chain dimensions as the temperature decreases with a gradual collapse from a loose random coil, high temperature state to a dense random coil, low temperature state. The stiffer polymers, on the other hand, exhibit increasing chain dimensions with decreasing temperature until at a critical temperature there is a sudden collapse to an ordered high density, low temperature state. This difference is due to the relative strength of the segment–segment attractive interactions compared to the energetic preference for a trans conformational state over a gauche state. When the attractive interaction is relatively strong (.
Solid-State NMR Studies of the Structure of Graphite Oxide

Graphite oxide (GO) and its derivatives have been studied using 13C and 1H NMR. The 13C NMR lines at 60, 70, and 130 ppm are assigned to C−OH, C−O−C, and >CC CC< double bonds are relatively stable, while C−OH groups may condense to form C−O−C (ether) linkages. There are at least two magnetically inequivalent C−OH sites, and the structure does not necessarily possess long-range order. Water molecules interact very strongly with the structure. The results reveal a number of new structural features.