Solid-State Thin-Film Sensors Based on Chalcogenide Materials Obtained by Planar Technology and Pulsed Laser Deposition

Methods of silicon planar technology and pulsed laser deposition were applied to fabricate fully solid-state chemical sensors for determining ions of copper, lead, cadmium, thallium, and also sulfide and chloride ions on the basis of thin chalcogenide films as ion-sensitive membranes.     

The quadrupole interaction at iodine impurities in a tellurium matrix derived from β-γ TDPAC experiments

Time differential perturbed angular correlation measurements on the implated single crystal system and , using an allowed - cascade, are reported. The information obtained, determines the orientation of the principal axes system of the electric fieldgradient and its value at room temperature. The results are compared with earlier Mössbauer effect measurements and the binding of an iodine impurity in tellurium is discussed.     

Copper(II) and nickel(II) complexes of 2-formylpyridine 3-piperidinyl-, 3-hexamethyleneiminyl- and 3-azabicyclo[3.2.2]nonylthiosemicarbazones

Summary Copper(II) and nickel(II) complexes of 2-formylpyridine 3-piperidinyl-, 3-hexamethyleneiminyl- and 3-azabicyclo-[3.2.2]nonylthiosemicarbazones were prepared and characterized spectroscopically. ¹H and ¹³C n.m.r. spectra of the thiosemicarbazones and a diamagnetic nickel(II) complex are reported, together with i.r., electronic and e.s.r. spectra of the metal complexes. The thiosemicarbazones and their copper(II) and nickel(II) complexes exhibit considerable growth inhibitory activity against Paecilomyces variotii, but show minimal activity against Aspergillus niger.     

Tuning of Supramolecular Architectures of l‐Valine‐Containing Dicyanoplatinum(II) 2,2′‐Bipyridine Complexes by Metal–Metal, π–π Stacking,and Hydrogen‐Bonding Interactions

A series of newly synthesized dicyanoplatinum(II) 2,2′‐bipyridine complexes exhibits self‐assembly properties in solution after the incorporation of the l ‐valine amino units appended with various hydrophobic motifs. These l ‐valine‐derived substituents were found to have critical control over the aggregation behaviors of the complexes in the solution state. On one hand, one of the complexes was found to exhibit interesting circularly polarized luminescence (CPL) signals at low temperature due to the formation of chiral spherical aggregates in the temperature‐dependent studies. On the other hand, systematic transformation from less uniform aggregates to well‐defined fibrous and rod‐like structures via Pt???Pt and π–π stacking interactions has also been observed in the mixed‐solvent studies. These changes were monitored by UV/Vis absorption, emission, circular dichroism (CD), and CPL spectroscopies, and morphologies were studied by electron microscopy.     

A theoretical model for core-annular flow of a very viscous oil core and a water annulus through a horizontal pipe

A theoretical model has been developed for core-annular flow of a very viscous oil core and a water annulus through a horizontal pipe. Special attention was paid to understanding how the buoyancy force on the core, resulting from any density difference between the oil and water, is counterbalanced. This problem was simplified by assuming the oil viscosity to be so high that any flow inside the core may be neglected and hence that there is no variation of the profile of the oil-water interface with time. In the model the core is assumed to be solid and the interface to be a solid/liquid interface.By means of the hydrodynamic lubrication theory it has been shown that the ripples on the interface moving with respect to the pipe wall can generate pressure variations in the annular layer. These result in a force acting perpendicularly on the core, which can counterbalance the buoyancy effect.To check the validity of the model, oil-water core-annular flow experiments have been carried out in a 5.08 cm and an 20.32-cm pipeline. Pressure drops measured have been compared with those calculated with the aid of the model. The agreement is satisfactory.     

Multiple-magnetic field 139La NMR and density functional theory investigation of the solid lanthanum(III) halides

Results from a solid-state ¹³⁹La NMR spectroscopic investigation of the anhydrous lanthanum(III) halides (LaX₃; X=F, Cl, Br, I) at applied magnetic fields of 7.0, 9.4, 11.7, 14.1, and 17.6 T are presented and highlight the advantages of working at high applied magnetic field strengths. The ¹³⁹La quadrupolar coupling constants are found to range from 15.55 to 24.0 MHz for LaCl₃ and LaI₃, respectively. The lanthanum isotropic chemical shifts exhibit an inverse halogen dependence with values ranging from −135 ppm for LaF₃ to 700 ppm for LaI₃, which represents nearly half of the total lanthanum chemical shift range. The spans of the magnetic shielding tensors also vary widely, from 35 to 650 ppm for the solid LaF₃ through LaI₃. DFT calculations of the ¹³⁹La electric field gradient and magnetic shielding tensors have been performed and provide a qualitative interpretation of the trends observed experimentally.     

The hydrodynamic stability of core-annular flow of two ideal liquids

The hydrodynamic stability of core-annular flow of two ideal liquids through a pipe is investigated. If the thickness of the annular layer is much smaller than the radius of the pipe, the pipe wall has a strong reducing effect on the growth velocity of possible Rayleigh-Taylor and Kelvin-Helmholtz instabilities at the interface between the two liquids.Shell Research N.V.     

Influence of gas injection on phase inversion in an oil–water flow through a vertical tube

An experimental study has been made of the influence of gas injection on the phase inversion between oil and water flowing through a vertical tube. Particular attention was paid to the influence on the critical concentration of oil and water where phase inversion occurs and on the pressure drop increase over the tube during phase inversion. By using different types of gas injectors also the influence of the bubble size of the injected gas on the phase inversion was studied. It was found that gas injection does not significantly change the critical concentration, but the influence on the pressure drop is considerable. For mixture velocities larger than 1 m/s, the pressure drop over the tube increases with decreasing bubble size and at inversion can become even larger than the pressure drop during the flow of oil and water without gas injection.     

Turbulence statistics from optical whole-field measurements in particle-laden turbulence

Obtaining turbulence statistics in particle-laden flows using optical whole-field measurements is complicated due to the inevitable data loss. The effects of this data loss are first studied using synthetic data and it is shown that the interpolation of missing data leads to biased results for the turbulence spectrum and its derived quantities. It is also shown that the use of overlapping interrogation regions in images with a low image density can lead to biased results due to oversampling. The slotting method is introduced for the processing of particle image velocimetry (PIV) data fields with missing data. Next to this, it is extended to handle unstructured data. Using experimental data obtained by a dual-camera PIV/PTV (particle tracking velocimetry) system in particle-laden grid turbulence, the performance of the new approach is studied. Some preliminary two-phase results are presented to indicate the significant improvement in the statistics, as well as to demonstrate the unique capabilities of the system.An erratum to this article can be found at

---

Synthesis,Electrochemistry, and Photophysical Studies of Ruthenium(II) Polypyridine Complexes with D–π–A–π–D Type Ligands and Their Application Studies as Organic Memories

A new class of ruthenium(II) polypyridine complexes with a series of D–π–A–π–D type (D=donor, A=acceptor) ligands was synthesized and characterized by ¹H NMR spectroscopy, mass spectrometry, and elemental analysis. The photophysical and electrochemical properties of the complexes were also investigated. The newly synthesized ruthenium(II) polypyridine complexes were found to exhibit two intense absorption bands at both high‐energy (λ=333–369 nm) and low‐energy (λ=520–535 nm) regions. They are assigned as intraligand (IL) π→π* transitions of the bipyridine (bpy) and π‐conjugated bpy ligands, and IL charge‐transfer (CT) transitions from the donor to the acceptor moiety with mixing of dπ(Ru^II)→π*(bpy) and dπ(Ru^II)→π*(L) MLCT characters, respectively. In addition, all complexes were demonstrated to exhibit intense red emissions at approximately λ=727–744 nm in degassed dichloromethane at 298 K or in n‐butyronitrile glass at 77 K. Nanosecond transient absorption (TA) spectroscopy has also been carried out, establishing the presence of the charge‐separated state. In order to understand the electrochemical properties of the complexes, cyclic voltammetry has also been performed. Two quasi‐reversible oxidation couples and three quasi‐reversible reduction couples were observed. One of the ruthenium(II) complexes has been utilized in the fabrication of memory devices, in which an ON/OFF current ratio of over 10⁴ was obtained.