The interfacial properties of MgCl(2) thin films grown on Si(111)7 x 7

Photoelectron spectroscopy with synchrotron radiation and low energy electron diffraction (LEED) were used in order to study the MgCl(2)Si(111) system. At submonolayer coverage of MgCl(2), a new LEED pattern was observed corresponding to a (sqr rt 3 x sqr rt 3)R30 degrees overlayer superimposed on the underlying reconstructed Si(111)7 x 7. The surface species at this stage are mainly molecular MgCl(2) and MgCl(x) (x<2) or MgO(x)Cl(y) attached to the Si substrate through Cl bridges coexisting with monodentate SiCl. The interfacial interaction becomes more pronounced when the submonolayer coverage is obtained by annealing thicker MgCl(2) layers, whereby desorption of molecular MgCl(2) is observed leaving on the nonreconstructed silicon surface an approximately 0.2 ML thick MgCl(x) layer which again forms the (sqr rt 3 x sqr rt 3 )R30 degrees superstructure.     

Polycyclic Aromatic Hydrocarbons in Wooden Railway Beams Impregnated with Coal Tar: Extraction and Quantification by GC-MS

 An analytical technique for the simultaneous determination of PAHs (polycyclic aromatic hydrocarbons) in wooden railway beams, impregnated with coal tar for their protection, has been developed, based on the effective extraction of the PAHs and their determination by GC-MS. Two extraction techniques, the Soxhlet and the ultrasonic one, using two different solvents, hexane and toluene have been compared for their efficiency for PAHs which can be determined in ppb-ppt range after optimised clean up and enrichment. Several parameters, such as the degree of impregnation of the wooden beams, the effect of sun radiation on the degradation of the PAHs and their migration to the soil have been investigated by following the concentration of the PAHs and that of their methylated products found at various sampling positions. The results are useful for the decision about recycling procedure or their further disposal.     

Low‐Temperature Restructuring Processes in Polyhydrosilanes

Summary: This paper presents the structural influence of the Si H functionality on the physicochemical properties of polysilanes. New low‐temperature restructuring processes were discovered using thermal analysis (TGA, DSC). Photoluminescent (FL) and X‐ray photoelectron spectroscopy (XPS) measurements revealed the optoelectronic properties‐chemical structure relationship of the synthesized polymers.

Highly reactive Si H groups lead to restructuring of the main polysilane chain.     

A framework for mapping the RFID-enabled process redesign in a simulation model

Empowered by the possibility to automatically identify unique product instances, the Radio Frequency Identification (RFID) technology is expected to revolutionize the supply chain processes. However, in view of the numerous possible ways that RFID can be implemented within the supply chain, the issue of supporting the design choices based on a credible assessment between the current (as-is) and the future (to-be) processes has become a matter of considerable concern and debate for both practitioners and academics alike. To design RFID implementations in the supply chain using a robust dynamic analysis, we resort to discrete event simulation. As a result, this paper conceptualizes the ‘RFID-enabled process redesign’ and proposes a framework regarding all possible types of RFID effects when integrating the technology within the supply chain processes. The research design was based on the empirical evidence through three case studies combined with the development of simulation models and on theoretical constructs regarding the information technology (IT)-enabled process redesign.     

Crystallographic report: Diphenylbis(Hpiroxicam)tin(IV), [Ph2Sn(Hpir)2]

The crystal structure of complex [Ph₂Sn(Hpir)₂ ·CH₃CN] shows for the first time chelation to a metal atom of piroxicam through the keto‐enolate oxygen atoms. Copyright © 2004 John Wiley & Sons, Ltd.     

Sub‐Micromolar Pulse Dipolar EPR Spectroscopy Reveals Increasing CuII‐labelling of Double‐Histidine Motifs with Lower Temperature

Electron paramagnetic resonance (EPR) distance measurements are making increasingly important contributions to the studies of biomolecules by providing highly accurate geometric constraints. Combining double‐histidine motifs with Cu^II spin labels can further increase the precision of distance measurements. It is also useful for proteins containing essential cysteines that can interfere with thiol‐specific labelling. However, the non‐covalent Cu^II coordination approach is vulnerable to low binding‐affinity. Herein, dissociation constants (K_D) are investigated directly from the modulation depths of relaxation‐induced dipolar modulation enhancement (RIDME) EPR experiments. This reveals low‐ to sub‐μm Cu^II K_Ds under EPR distance measurement conditions at cryogenic temperatures. We show the feasibility of exploiting the double‐histidine motif for EPR applications even at sub‐μm protein concentrations in orthogonally labelled Cu^II–nitroxide systems using a commercial Q‐band EPR instrument.     

Nanostructure Engineering of Metal–Organic Derived Frameworks: Cobalt Phosphide Embedded in Carbon Nanotubes as an Efficient ORR Catalyst

Heteroatom doping is considered an efficient strategy when tuning the electronic and structural modulation of catalysts to achieve improved performance towards renewable energy applications. Herein, we synthesized a series of carbon-based hierarchical nanostructures through the controlled pyrolysis of Co-MOF (metal organic framework) precursors followed by in situ phosphidation. Two kinds of catalysts were prepared: metal nanoparticles embedded in carbon nanotubes, and metal nanoparticles dispersed on the carbon surface. The results proved that the metal nanoparticles embedded in carbon nanotubes exhibit enhanced ORR electrocatalytic performance, owed to the enriched catalytic sites and the mass transfer facilitating channels provided by the hierarchical porous structure of the carbon nanotubes. Furthermore, the phosphidation of the metal nanoparticles embedded in carbon nanotubes (P-Co-CNTs) increases the surface area and porosity, resulting in faster electron transfer, greater conductivity, and lower charge transfer resistance towards ORR pathways. The P-Co-CNT catalyst shows a half-wave potential of 0.887 V, a Tafel slope of 67 mV dec⁻¹, and robust stability, which are comparatively better than the precious metal catalyst (Pt/C). Conclusively, this study delivers a novel path for designing multiple crystal phases with improved catalytic performance for energy devices.