Preparation of Porous Titania Film by Modified Sol-Gel Method and its Application to Photocatalyst

Sol-Gel derived mesoporous titania films with controlled pore sizes were prepared by surfactant templating. The coating sol was obtained by hydrolysis of Ti(OC₄H₉)₄ in ethanol/HCl solution. The gel films, prepared by spin coating on glass substrate, were dried after immersion in surfactant solutions under an atmospheric pressure. The porous films of anatase with columnar and rectangular structure were obtained after annealing at 500°C. The annealed films are transparent and 80–140 nm in thickness. Refractive indices of the films with surfactant immersion were 10–20% lower than those of the films without immersion. The spacing between the columns or rectangular grains and the grain shape were found to depend on the surfactant species. The pohoto-catalytic activity of the films for the oxidation of NO _x was improved by the surfactant modification.     

The role of octanol in the extraction of hydrochloric acid by trilaurylamine dissolved in benzene

The extraction of hydrochloric acid by trilaurylamine (TLA) dissolved in benzene was studied in the presence and in absence of n-octanol. The extraction of HCl was found to be enhanced by the addition of octanoi to the organic phase. In order to explain this effect by means of the law of mass action, the systems TLA-HCL-benzene and n-octanol-HCl-benzene as well as TLA-octanol-benzene were also studied. It was found that TLA reacts with octanol to form a complex, TLAROH, while the octanol itself associates in benzene to form dimers and tetramers, although it does not extract HCl alone from the dilute solutions used in the present study. The enhancement of the extraction of HCl by TLA upon the addition of n-octanol could be described by the formation of the species TLA·ROH·HCl and its stability constant was determined.     

High performance platinized titanium nitride catalyst for methanol oxidation

Platinized TiN is shown to be a very good catalyst for the electrochemical oxidation of methanol; it does not contain Ru and the CO poisoning effect is alleviated by the presence of TiN.     

Mechanism of signal uncertainty generation for laser-induced breakdown spectroscopy

Relatively large measurement uncertainty severely hindered wide application for laser-induced breakdown spectroscopy (LIBS), therefore it is of great importance to understand the mechanism of signal uncertainty generation, including initiation and propagation. It has been found that the fluctuation of plasma morphology was the main reason for signal uncertainty. However, it still remains unclear what mechanism leads to laser-induced plasma morphology fluctuation. In the present work, we employed three fast-imaging cameras to capture three successive plasma images from a same laser-induced Titanium alloy plasma, which enables us to understand more clearly of the plasma evolution process especially for the early plasma evolution stage when plasma and surrounding gases interact drastically. Seen from the images, the plasma experienced an increasing morphological fluctuation as delay time increased, transforming from a “stable plasma” before the delay time of 100 ns to a “fluctuating plasma” after the delay time of 300 ns. Notably, the frontier part of plasma showed a significant downward motion from the delay time of 150 ns to 200 ns and crashed with the lower part of the plasma, making the plasma flatter and later even splitting the plasma into two parts, which was considered as a critical process for the transformation of “stable plasma” to “unstable plasma”. By calculating the correlation coefficient of plasma image pairs at successive delay times, it was found that the higher the similarity between two plasma at early stage, the more similar at later stage; this implied that the tiny plasma fluctuation earlier than the critical delay time (150–200 ns) was amplified, causing a large plasma fluctuation at the later stage as well as LIBS measurement uncertainty. The initiation of slight fluctuation was linked with Rayleigh–Taylor Instability (RTI) due to the drastic material interpenetration at the plasma-ambient gas interface at earlier stage (before 50 ns). That is, the uncertainty generation of LIBS was proposed as: plasma morphology fluctuation was inevitably trigged by RTI at the early stage and the tiny fluctuation was amplified by the back pressed downward process of plasma frontier material, leading to severe morphology fluctuation as well as LIBS signal uncertainty.     

Investigating the impurity structure for Fe3+ ions doped into rutile titanium dioxide single crystal

The local environment around Fe³⁺ centers in rutile TiO₂ crystals is studied by employing fourth-order perturbation theory formula based on the dominant spin–orbit coupling mechanism. The zero-field splitting parameters (ZFSPs) D and E and crystal field parameters are modeled for the Fe³⁺ ions not only at the substitution Ti⁴⁺ site, but also at the interstitial site with local symmetry D_2h. In order to acquire the best agreement between the calculated ZFSPs and those measured by electron magnetic resonance, the model parameters are adjusted on the basis of several approaches. This enables us to determine the feasible values of the structural distortions resulting from dopant Fe³⁺ ions. Consequently, it is confirmed that Fe³⁺ ions substitute for Ti⁴⁺ sites in rutile TiO₂ crystals.     

Palladium-catalyzed alkoxycarbonylation of (Z)-2-en-4-yn carbonates leading to 2,3,5-trienoates

Pd(0)-catalyzed carbonylation of (Z)-2-en-4-yn carbonates in the presence of a balloon pressure of CO in an alcohol donates vinylallenyl esters with an exclusively E-configuration and in high yields. The fact that no such reactivity could be observed with E-configured enyne carbonates may indicate that the reaction is promoted via the cooperative coordination of palladium with both alkynyl and carbonate moieties.     

Isolable, gold carbonyl complexes supported by N-heterocyclic carbenes

Cationic gold carbonyl complexes supported by N-heterocyclic carbene ligands, SIDipp and IDipp, have been synthesized. [(SIDipp)Au(CO)][SbF(6)] has a linear, two-coordinate gold center. [(SIDipp)Au(CO)][SbF(6)] and [(IDipp)Au(CO)][SbF(6)] display ?ν(CO) values at 2197 and 2193 cm(-1), respectively. Computational studies on [(SIMe)Au(CO)](+) indicate the presence of a strong Au(I)-CO bond.     

Supports of Weighted Equilibrium Measures and Examples

We analyze the supports of weighted equilibrium measures in ? ⁿ . We give explicit examples of families of compact sets which arise as the support of a weighted equilibrium measure for some admissible weight w. These examples also give new constructions of plurisubharmonic functions in the Lelong class. We also include a list of open problems on the support of extremal measures which are related to solutions of Monge–Ampère equations.     

Evaluating Mohr–Coulomb yield criterion for plastic flow in model metallic glasses

The yielding of metallic glasses (MGs) is generally considered to be dependent on pressure or normal stress, which is usually described by the Mohr–Coulomb yield criterion. Experimentally, the orientation of the shear band angle or fracture angles in MG is roughly 40° to 42° in uniaxial compression and 50° to 59° in uniaxial tension, both with respect to the loading direction. However, the amounts of deviation from the maximum shear stress direction (45°) under uniaxial tension and compression are quite different, which seems to be inconsistent with the Mohr–Coulomb yield criterion. Here we carried out molecular dynamics simulations to study the incipient plasticity of model Dzugutov glasses subjected to various uniaxial and biaxial stress states. The yield points are defined as the sharp rise of the population of atoms participating in non-affine deformations, in addition to the traditional offset method. The yield surfaces thus created agree well with the Mohr–Coulomb yield criterion. Furthermore, the orientations of the embryonic shear bands (instead of the fully-grown shear bands, or fracture planes) are measured, which also follow predictions based on the Mohr–Coulomb criterion. Our simulation results call for orientational measurement of incipient shear bands in experiments to critically examine the Mohr–Coulomb yield criterion in MG systems.     

Total synthesis of 7'-desmethylkealiiquinone

The total synthesis of an analogue of the marine alkaloid kealiiquinone has been completed through application of an intramolecular Diels-Alder reaction of an imidazole-containing enyne. Oxidative aromatization of the lactone adduct and N-methylation facilitates C2-oxidation via the imidazolium salt. Conversion of the lactone to the phthalaldehyde derivative and then to the dihydroxybenzoquinone was achieved via a reaction with glyoxal in the presence of KCN. Esterification of the vinylogous diacid and deprotection provided 7'-desmethylkealiiquinone.