Making Large‐Area Titanium Disulfide Films at Reduced Temperature by Balancing the Kinetics of Sulfurization and Roughening

The synthesis of large‐area TiS₂ thin films is reported at temperatures as low as 500 °C using a scalable two‐step method of metal film deposition followed by sulfurization in an H₂S gas furnace. It is demonstrated that the lowest‐achievable sulfurization temperature depends strongly on the oxygen background during sulfurization. This dependence arises because Ti? O bonds present a substantial kinetic and thermodynamic barrier to TiS₂ formation. Lowering the sulfurization temperature is important to make smooth films, and to enable integration of TiS₂ and related transition metal dichalcogenides—including metastable phases and alloys—into device technology.     

Relationship between basicity and nucleophilicity

The empirical concepts of basicity and nucleophilicity are related but not strictly proportional. Hence, the aim of this study is to help in elucidating the range where both concepts are directly proportional. To do this, the relationship between a recently introduced nucleophilicity index and the proton affinity (PA) of several families of bases has been studied. A good correlation between the PA and the nucleophilicity index using HF and HCN as electrophilic partner has been found. Our studies show that the correlation exists only when the interaction is soft–soft in character and for strong bases with weak acids. However, the relationship is not only valid for exothermic reactions as it has been previously postulated but also for endothermic reactions. Copyright © 2007 John Wiley & Sons, Ltd.     

Decomposition of 1,1-dichloroethene on Pd(111)

The decomposition of 1,1-dichloroethene on Pd(111) is investigated using conventional thermal desorption, laser-induced thermal desorption (LITD), and FT reflection absorption infrared spectroscopy (FT-RAIRS). The decomposition mechanism produces at least three hydrocarbon surface intermediates, including ethylidyne. Thermal desorption results differ between high and low coverages because of relative surface concentrations of Cl and H in combination with kinetic effects.     

Multi-Decision-Makers Equalizer: A Multiobjective Decision Support System for Multiple Decision-Makers

In this paper we present a decision support system that helps to solve multiobjective decision problems considering a multi decision-makers framework. By an iterative procedure this system looks for a single solution that satisfies all decision-makers equally. The negotiation process requires that each decision-maker trade certain benefits in some of the objectives being analyzed for benefits in others. Finally a compromise solution should be obtained.     

Measurement of atmospheric opacity at 278 GHz at McMurdo Station,Antarctica in austral spring seasons, 1986 and 1987

We present a quasi-continuous record of measured atmospheric opacity obtained at 278 GHz (1.1 mm wavelength) from McMurdo Station, Antarctica during austral spring seasons in 1986 and 1987. McMurdo Station, at 78°S, 166°W, is easier to access than the Amundsen-Scott (South Pole) Station, although representing a warmer, sea level site with substantially higher typical opacity: the present record may be of interest to those contemplating mm-wave astronomical or atmospheric observations within the Antarctic region. Observations were made over a 256 MHz bandpass in 1986, during the period August 30 to October 30. In 1987, a 512 MHz bandpass was used, and observations were made during the period September 4 to October 13. All data are reduced to represent opacity in the zenith direction, and measurements were taken approximately every 20 minutes, except during storms or other periods of high opacity. The periods covered represent transitions from the polar winter towards summer conditions, and thus represent neither the best nor the worst that this site has to offer.     

Combinatorial electrochemical synthesis and characterization of tungsten-based mixed-metal oxides

Automated systems for electrochemical synthesis and high-throughput screening of photoelectrochemical materials were developed and used to prepare tungsten-based mixed-metal oxides, W(n)O(m)M(x) [M = Ni, Co, Cu, Zn, Pt, Ru, Rh, Pd, and Ag], specifically for hydrogen production by photoelectrolysis of water. Two-dimensional arrays (libraries) of diverse metal oxides were synthesized by automated cathodic electrodeposition of the oxides on Ti foil substrates. Electrolytes for the mixed oxides were prepared from various metal salts added to a solution containing tungsten stabilized as a peroxo complex. Electrodeposition of the peroxo-stabilized cations gave rise to three distinguishable oxide groups: (1) mixed-metal oxides [Ni], (2) metal-doped tungsten oxides [Pt, Ru, Rh, Pd, Ag], and (3) metal-metal oxide composites [Co, Cu, Zn]. The oxides typically showed n-type semiconducting behavior. Automated measurement of photocurrent using a scanning photoelectrochemical cell showed the W-Ni mixed oxide had the largest relative zero bias photocurrent, particularly at a low Ni concentration (5-10 atomic percent Ni). Pt and Ru were also found to increase the photoactivity of bulk tungsten oxide at relatively low concentrations; however, at concentrations above 5 atomic percent, crystallization of WO(3) was inhibited and photoactivity was diminished. Addition of Co, Cu, and Zn to WO(3) was not found to improve the photoelectrochemical activity.