Miracle-dz/UniFAR-FTUs huggingface dataset:
Multiple transition states in unimolecular reactions: A transition state switching model. Application to the C4H8 +⋅ system

A transition state switching model is developed for use in systems where more than one transition state occurs along the reaction coordinate. The model is cast in the perspective of both the unified statistical theory (UST) of Miller and of variational transition state theory. The basic assumptions are those common to transition state theory and RRKM–QET. A reaction branching analysis leads to reaction probabilities for a number of potential surfaces and appropriate expressions are delineated for both unimolecular and bimolecular reactions. The theory is developed from a microcanonical viewpoint and rigorously conserves both energy E and angular momentum J. Comparison is made with experimental data for the C4H8 +⋅ system where absolute unimolecular rate constants and branching ratios have been measured as a function of energy, bimolecular rate constants, and branching ratios measured at room temperature (the ethylene ion–molecule reaction), the lifetime of C4H8 +⋅ measured when formed by the ethylene ion–.
Development of chemiluminescent biosensing of nucleic acids based on oligonucleotide-immobilized gold surfaces

A chemiluminescent biosensing method was developed based on the immobilization of DNA probes on a gold surface by the self-assembled monolayers technique. The complementary sequence was detected by coupling avidin–alkaline phosphatase to the biotinylated oligonucleotide and measuring the chemiluminescent signal obtained from the hydrolysis of the substrate 3-(2′-spiroadamantane)-4-methoxy-4-(3″-phosphoryloxy)phenyl- 1,2-dioxetane by this enzyme. The method has a wide calibration range of five orders of magnitude and the detection limit is 15 pM (signal-to-ratio = 3). The factors affecting the probe immobilization, target hybridization and sensitivity were investigated. The method was also applied to detect specific DNA fragments relative to the hepatitis B plasmid.
Bulk properties of two‐phase disordered media. III. New bounds on the effective conductivity of dispersions of penetrable spheres

Rigorous upper and lower bounds on the effective electrical conductivity σ * of a two‐phase material composed of equi‐sized spheres distributed with an arbitrary degree of impenetrability in a matrix are obtained and studied. In general, the bounds depend upon, among other quantities, the point/n‐particle distribution functions G(i)n, which are probability density functions associated with finding a point in phase i and a particular configuration of n spheres. The G(i)n are shown to be related to the ρn, the probability density functions associated with finding a particular configuration of n partially penetrable spheres in a matrix. General asymptotic and bounding properties of the G(i)n are given. New results for the G(i)n are presented for totally impenetrable spheres, fully penetrable spheres (i.e., randomly centered spheres), and sphere distributions between these latter two extremes. The so‐called first‐order cluster bounds on σ * derived here are given exactly through second order in the sphere vol.
Algorithms and Platforms for Quantum Science and Technology

The field of quantum science and technology has seen tremendous recent progress. Despite this, building large-scale quantum devices remains daunting as fault tolerance is a distant goal in all current experimental platforms. This dissertation discusses two complementary avenues towards practically relevant quantum technologies. In the first part, we explore physically inspired quantum algorithms that run on near-term devices without quantum error correction. We investigate the robustness of adiabatic quantum algorithms, placing stringent requirements on noise induced by the environment. In addition, we construct quantum algorithms that sample from classical Gibbs distributions. These algorithms elucidate connections between computational complexity and phase transitions and provide physical insight into the origin of quantum speedup. The second part focuses on novel platforms and optical interfaces for quantum applications. We demonstrate that optical resonances in ordered arrays of atoms and atomically thin semiconductors offer a powerful tool to control and manipulate light at both the classical and single-photon level. We further study interactions between optical excitations and charge carriers in two-dimensional semiconductors, which give rise to complex quantum manybody dynamics in a largely unexplored regime.
Prediction of Triple-Point Temperature of Pure Components Using their Chemical Structures

A quantitative structure property relationship study was performed to develop a model for the prediction of triple-point temperature of pure components. For developing this model, 638 pure components were used, and, for whichever, 1664 molecular descriptors were determined. As a standard tool for subset variable selection, genetic algorithm-based multivariate linear regression (GA-MLR) technique was used. The obtained model is a seven parameters multilinear equation that has a squared correlation coefficient of 0.9410 (R2 = 0.9410).
Minimization of interferences in inductively coupled plasma mass spectrometry using on-line preconcentration

A semiautomated system is used to preconcentrate Ti, V, Mn, Fe, Co, Ni, Cu, Cd, and Pb, in order to remove high salt matrices. The preconcentration system accepts digests with acid concentrations equivalent to 0.8-1.4% HNO{sub 3}, neutralizes them, and loads them onto a macroporous iminodiacetate resin. The alkali and alkaline-earth metals, along with deleterious anions such as chloride, are washed off the resin before and analyte metals are eluted with nitric acid. A total of 13 isotopes of the analytes are measured. An examination of the apparent concentration efficiencies, as well as the behavior of two internal standard elements added to the eluate stream, indicates that the elution front matrix enhances the inductively coupled plasma mass spectrometry response of the analytes. Investigation of the nature of the blank signal suggests that the detection limits of several of the isotopes could benefit by much larger preconcentration factors, while those of vanadium, copper, cadmium, and lead are currently limited by reagent purity and laboratory contamination. The preconcentration system is evaluated on several simple synthetic matrices, as well as on synthetic seawater and three wastewaters. Digestion of samples containing natural organic chelators is required.
Interest Rate Pegging, Fluctuations, and Fiscal Policy in China

This paper proves in a New Keynesian model that interest rate pegging can explain the unusual business cycle fluctuations in China. It is traditional wisdom that when the nominal interest rate is inflexible, there is no unique equilibrium in macroeconomic models. We prove that a unique equilibrium exists if the nominal rate is pegged for a limited period, after which it switches to a flexible rate regime. The peg alters the propagation of external shocks, magnifies volatility of endogenous variables, and leads to instability of the economy. Besides, the model becomes more unstable when the peg duration extends, and when the pegged rate deviates from steady state. At the same time, fiscal multiplier increases under the peg, indicating fiscal policy may be more effective in mitigating economic fluctuations when monetary policy is restricted by interest rate pegging.
A novel inductively coupled plasma atomic emission spectrometry method for uranium isotope ratio measurements using chemometric techniques

Inductively coupled plasma atomic emission spectrometry was applied for uranium isotope ratio measurement. Even high resolution spectrometers cannot resolve small isotopic shift between 235U and 238U emission lines. Multivariate calibration techniques are useful tools for overcoming spectral overlap. The emission spectra of natural and depleted uranium samples were modelled by the laboratory written PLS-2 program (according to PLS algorithm). Four factors were selected as the optimum number of factors. The PLS model was applied on an independent test set. The results were validated by thermal ionization mass spectrometry (TIMS). A good agreement between the predicted results from the PLS-2 model and the TIMS results were obtained.
Pressure dependence of crystal structure and molecular packing in anthracene

Anthracene molecular crystal has been investigated up to a pressure of 10.5 GPa at room temperature using variable shape variable size Monte Carlo simulations in an isothermal–isobaric ensemble. We have reported various structural quantities, such as cell parameters and unit cell volume, as a function of pressure and compared them with the experimental results [J. Chem. Phys. 119, 1078 (2003)]. The pressure dependence of angles θ, δ and χ which describe the relative packing of molecules in the crystal has been calculated. We report that anthracene molecular crystal does not exhibit any first order phase transition up to a pressure of 10.5 GPa which is consistent with the experimental observations by Oehzelt et al. [Phys. Rev. B 66, 174104 (2002)]. The calculated equation of state (EOS) has been fitted to a Murnaghan-type EOS with good agreement. The calculated bulk modulus and the pressure derivative of bulk modulus are 8.2 GPa and 8.9 respectively which are in agreement with the experimentally calculated.
Fabrication and Optical Property of Self-Organized Honeycomb-Patterned Films

By using self-organization of water droplets formed in casting process of polymers, we have fabricated polymer films with hexagonally ordered micropores, termed honeycomb-patterned films, and attempted to apply them as photonic crystals. Optical properties of the honeycomb films are measured by FT-IR spectroscopy. A broad band attributed to the periodic structure is newly observed in the IR absorption spectrum of the honeycomb film.
Effect of solvent vapor on optical properties of Pr4VOPc in polymethylmethacrylate

Dye‐in‐polymer (DIP) films consisting of soluble Pr4VOPc (vanadyl phthalocyanine having four propyl substituents) dye and polymethylmethacrylate (PMMA) were prepared by spin‐coating process. Pr4VOPc precipitates as a glassy phase in pure PMMA matrix during the film formation. Upon exposure of these DIP films to organic solvent vapor, stable crystalline Pr4VOPc, which has stronger absorption in the near‐IR region and larger nonlinear refractive index n2 than the glassy phase, forms. The organic solvent vapor promotes the solubilization and crystallization of the dye, plastication of the polymer chains, and migration of the dye. The nonlinear refractive index n2 and optical spectra of the DIP films were measured, and the change rule has been discussed in terms of electron transition and molecular packing of Pr4VOPc.
Improved Energy Storage Density in Barium Strontium Titanate by Addition of BaO-SiO2-B2O3 Glass

The energy storage density of a Ba0.4Sr0. 6TiO3 ceramic with the addition of 5–20 vol% glass was investigated. The results show that the improvement of the energy density in glass-added Ba0.4Sr0. 6TiO3 samples arises due to two factors: one is that the breakdown strength is notably improved due to the decrease of the porosity and the reduction of the grain size and pore size in glass-added samples and the other is that the remnant polarization of glass-added samples is decreased. The energy density of the samples containing 5 vol% glass additive was improved by a factor of 2.4 compared with that of pure Ba0.4Sr0. 6TiO3.
Die Intra-Cluster-Correlation im Kontext der Fallzahlschätzung cluster-randomisierter Studien in der Pflegewissenschaft

Bei cluster-randomisierten Interventionsstudien im Rahmen der Pflegeforschung erfolgt die Randomisierung in der Regel nicht uber Individuen sondern uber Pflegeeinheiten, z.B. Stationen. Der Einfluss der Clusterzugehorigkeit auf den Interventionseffekt wird als Intra-Cluster-Correlation (ICC) bezeichnet und ist bereits bei der Fallzahlschatzung zu berucksichtigen. Dieser Wert ist jedoch bei Studienbeginn nicht bekannt, so dass auf bereits veroffentlichte Werte aus vorangegangenen Studien zuruck gegriffen werden muss (Kus et al., 2009). In dieser Arbeit werden verschiedene Schatzer zur Bestimmung der ICC vorgestellt sowie die ICC fur verschiedene Variablen im Rahmen einer Sekundaranalyse ermittelt. Im Theorieteil dieser Arbeit werden die Methode des Hypothesentestens in ihrer Entwicklung sowie die Bedeutung von Signifikanzniveau und Power beschrieben. Die den Untersuchungen meist zugrunde liegenden konventionellen Werte fur Signifikanzniveau und Power werden kritisch hinterfragt. Im Rahmen der Datenanalyse wurde eine Sekundaranalyse der am Lehrstuhl fur Statistik und standardisierte Methoden fur Pflegeforschung der Philosophisch-Theologischen Hochschule Vallendar erhobenen Daten der PiSaar-Studie (Bruhl, Planer, 2013) durchgefuhrt. Auf Grundlage des Common-Correlation-Modells wurde die ICC fur ausgewahlte personenbezogene Variablen mit unterschiedlichen Schatzern bestimmt und verglichen. Die Schatzer wurden sowohl auf die Grundgesamtheit sowie auf heterogene Clustergrosen angewendet. In einem weiteren Schritt wurde untersucht, inwiefern die Eignung der Schatzer von der Erfolgsrate der untersuchten Variablen abhangt. In Form einer Simulationsstudie wurden die ICC mit den untersuchten Schatzern uber alle moglichen Kombinationen aus k=2 und k=3 Clustern sowohl uber alle Wohnbereiche als auch nach gruppierten Wohnbereichsgrosen berechnet. Erganzend werden die berichteten ICC aus der Ulmer Sturzstudie (Kron, 2003) sowie aus zwei Studien von Meyer et al. (2009) und Kopke et al. (2012) zur Fixierung in Altenheimen zusammenfassend dargestellt. Die Ergebnisse zeigen zum einen, dass die ICC hohe Werte annehmen kann, die bei der Fallzahlschatzung nicht unberucksichtigt bleiben durfen. Zum anderen wird deutlich, dass die ICC insbesondere dort hoch ausfallt, wo die Einschatzung des Bewohnerzustandes nicht auf objektiven Daten sondern auf fachlicher Expertise der Pflegefachkrafte beruht. Somit sind die ICC-Werte fur solche Variablen nur sehr begrenzt auf andere Studien ubertragbar. Die sicherste Methode zur Schatzung der ICC im Vorfeld einer Untersuchung bleibt daher die Durchfuhrung einer eigenen Vorstudie. Als einfaches und stabiles Verfahren fur die Ermittlung der ICC hat sich der Varianzanalyse-Schatzer erwiesen.
Medium-Range Order in Sol–Gel Prepared Al2O3–SiO2 Glasses: New Results from Solid-State NMR

The medium-range order of 0.5Al2O3–xSiO2 glasses (1 ≤ x ≤ 6) prepared via a new sol–gel route from the Al lactate precursor has been studied by 29Si and 27Al single- and double-resonance solid-state NMR techniques. For high-alumina samples Si–O–Al connectivities are detected by 29Si MAS NMR as well as by 29Si{27Al} rotational echo adiabatic passage double-resonance (REAPDOR) spectroscopy. To boost the signal-to-noise ratio, the REAPDOR experiment was combined with a Carr–Purcell–Meiboom–Gill (CPMG) echo train acquisition. While all five silicon units Q(4)mAl (0 ≤ m ≤ 4) are detectable in appreciable concentrations for x = 1, the spectra indicate that the average number of Al species bound to silicon, ⟨mAl⟩, gradually decreases toward higher x values, as expected. The 27Al MAS NMR spectra reveal four-, five-, and six-coordinated aluminum in these glasses. For x ≥ 3, the Al species detected are essentially independent of sample composition indicating a constant structural environment of Al. In contrast, for.
Recent Developments in the Assessment of Thermal Risks of Chemical Processes

In the past two decades, the assessment of thermal risks linked to the practice of chemical reactions on an industrial scale has made great progress. Nowadays chemists understand these risks and are able to assess them. Nevertheless, incidents still occur which indicate that some weaknesses still exist, especially in risk management systems. Recent developments aim at providing production staff with improved tools for the assessment of these risks and also for training purposes. Furthermore, for some special situations, more specific and more accurate experimental techniques and estimation methods are required. In the present paper, some recent developments realized in our safety research laboratories are reviewed.
Implementation of Radioactive 85Kr for Ventilation Rate Measurements in Dairy Barns

Quantifying gaseous emissions from naturally ventilated animal buildings is a particularly difficult task and associated with large uncertainties. One aspect is to measure the ventilation rate and then to quantify the gaseous emissions. Therefore, the ventilation rate was determined by two methods, simultaneously. Fifteen field experiments were carried out to study the ventilation rate in a naturally ventilated dairy barn located in Northern Germany during three consecutive winter seasons. The air exchange rates and then the ventilation rates were determined by the decay of the radioactive tracer Krypton-85, and the carbon dioxide (CO2) balance which is the reference method. Afterwards, the results were compared with each other by developing a linear regression model and carrying out Pearson correlation analysis. During each field experiment, continuous measurements of gas concentrations (NH3, CO2, CH4, and N2O) inside and outside the building and 85Kr tracer gas experiments were carried out. Meanwhile, the microclimatic and climatic conditions were measured and recorded. The tracer gas technique was further developed for better application through winter measurements. Where, eight combination factors were tested which are: 85Kr line release source vs. 85Kr point release source, average a-values vs. sum impulses, selected radiation counters vs. all radiation counters. The differences between the reference method and the eight factor combinations were tested using the ANOVA model. The results showed that the best factor combinations were: (1) line release source considering the impulses recorded by selected radiation counters and implementing the sum method of all impulses where high R-square value of 0.82 and reliable parameter estimate of 1.00±0.19 were found for this combination, and (2) point release source considering the impulses recorded by all radiation counters and implementing the sum method of all impulses where high R-square value of 0.91 and reliable parameter estimate of 1.19±0.15 were found for this combination. The average gaseous emissions through the different winter seasons, subject to the reference method, were 2.9, 14.5, 1785, and 1.6 g h-1 AU-1 for NH3, CH4, CO2, and N2O respectively.
Comparative experimental study of methane adsorption on multi-walled carbon nanotubes and granular activated carbons

In this study, methane storage capacity of granular activated carbons (GACs) and two types of multi-walled carbon nanotubes (MWCNTs) was investigated and compared. An experimental apparatus consisting a dual adsorption vessel was set up for measurement of equilibrium adsorption of methane on adsorbents using volumetric technique at pressure range of 0–50 bar at different temperatures. The first type of MWCNs has shown lower methane uptake (4.5 mmol g−1) compared to GACs (6.5 mmol g−1) at the temperature of 283.15 K and the pressure of 50 bar, while 33 mmol g−1 of methane storage capacity was achieved using the second type of MWCNTs that is much higher than methane storage on GACs at the same operating conditions. The superior uptake performance for the second type of MWCNTs can be attributed to its specific characteristics such as smaller pore size and higher pore volume. The experimental data of adsorption were almost equally well described by Langmuir, Freundlich and Sips equations to determine the model isotherms. The isosteric heat of methane adsorption on the adsorbent was calculated based on Clausius–Clapeyron and the Sips isotherm model using the experimental data at different temperatures. Results revealed that the isosteric heat of methane adsorption on MWCNTs was lower than the heat of methane adsorption on GACs. Low values obtained for isosteric heats of adsorption indicated dominance of physisorption mechanism for all adsorbents. In general, the obtained data indicated that some well-structured MWCNTs with uniform and narrow size distribution as well as higher pore volume are potential materials for methane storage and deserve further study.
Ba2NiTeO6 – eine neue Verbindung in der Reihe der hexagonalen Perowskite

Die Struktur der Verbindung (Ba2)(12) (NiIITeVI)(6)O6 wurde mit Hilfe von Einkristall-Rontgen-Beugungsdaten ermittelt und bis zu einem R-Wert von 2,9% verfeinert. Ba2NiTeO6 kristallisiert rhomboedrisch (Raumgruppe R3m) mit a = 5,797 und c = 28,595 A fur die trigonal aufgestellte Elementarzelle, die sechs Formeleinheiten enthalt. Sie besteht aus dichtest gepackten BaO3-Schichten mit einer Stapelfolge hhcchhcc…. In der resultierenden 12-Schichtenstruktur sind die Sauerstoffoktaeder schichtweise alternierend von Ni und Te besetzt. Gruppen von jeweils drei flachenverknupften Oktaedern sind uber TeO6-Oktaeder, die nur Eckenverknupfungen zeigen, miteinander verbunden. Von den drei flachenverknupften Oktaedern ist jeweils das mittlere mit Te besetzt, die auseren mit Ni. Die Bindungsverhaltnisse werden mit Hilfe der Ligandenfeldspektren im Vergleich zu ahnlichen Verbindungen diskutiert. Es wird gezeigt, das sich der Ligandenfeldparameter Δ entgegen den Voraussagen der elektrostatischen Kristallfeldtheorie auch dann sehr erheblich andern kann (etwa 30%), wenn die Ni — O-Abstande praktisch gleich bleiben. Ein solcher Effekt ist unter gewissen strukturell-geometrischen Voraussetzungen immer dann zu beobachten, wenn man die Bindungsverhaltnisse innerhalb der NiO6-Oktaeder mittelbar durch die Substitution eines s2p6-(W6+) durch ein d10-konfiguriertes Kation (Te6+) in der kationischen Umgebung der Ni2+-Ionen andert. Ba2NiTeO6 — a novel compound in the series of hexagonal perovskites (Ba2)(12)(NiTe)(6)O6 crystallizes in the rhombohedral space group R3m with a = 5.797 and c = 28.595 A for the unit cell in the trigonal setting, which contains 6 formula units. The crystal structure was solved by single crystal X-ray diffraction and refined down to R = 2.9%. It can be described by 12 close-packed BaO3 layers alternating in the sequence hhcchhcc…, with an ordered occupation of the octahedral lattice sites by Ni and Te atoms. Groups of three octahedra, which are connected with one another by common faces, are linked with each other by TeO6 octahedra via common corners. The central octahedra of these face-linked groups are occupied by Te, the outer ones by Ni. The bonding within the NiO6 polyhedra is discussed on the basis of the ligand field spectra and compared to similar compounds. It is shown that there can be an appreciable change of the ligand field parameter Δ (30%) even when the Ni — O distances are nearly equal — in contrast to the predictions of the crystal field theory. Effects of this kind are observed under certain structural conditions, when the bonding within the NiO6 polyhedra is changed indirectly by substitution of atoms with a noble gas configuration (W6+) by atoms with a d10-configuration (Te6+) in the cationic environment of Ni2+.
Coalescence of Air Bubbles in Aqueous Solutions of Ionic Surfactants in Presence of Inorganic Salt

This work presents a study on adsorption characteristics of two anionic (SDS and SDBS) and one cationic (CTAB) surfactants at air–water interface in presence of inorganic salt (NaCl). Coalescence of air bubbles in these solutions is studied by measuring the rest time of air bubbles at flat air–water interface. Significant effects of salt on surface tension and coalescence are observed. Surface tension is reduced in presence of salt and rest time is increased. The stochastic model developed earlier by Ghosh and Juvekar (2002; Chem Eng Res Des, 80: 715–728) fits the rest time distributions very well. A comparison of seven film-drainage models with the mean values of these distributions is presented. It is observed that these models, within the limitations of the simplifying assumptions behind their development, can not predict the values of rest time accurately.