Graphite formation on Ni film by chemical vapor deposition

Thin film formation of graphite by chemical vapor deposition using 2-methyl-1,2′-naphthyl ketone as a starting material was carried out on Ni film substrates. On Ni films directly deposited on quartz glass, the graphite films were obtained when the Ni film thickness was above 1 000 Å and above 5 000 Å at 700 °C and 1 000 °C, respectively. Depositions on thinner Ni film substrates comprise amorphous carbon (a-C) or graphite tubes which was owing to the thermal coagulation of the Ni film into droplets. On the other hand, graphite film was obtained on the Ni film with thickness 10 Å when a-C was inserted between the Ni film and the quartz glass. The coagulation of the Ni film is considered to be avoided by inserting a-C layer.     

Potential bile acid metabolites. 24. An efficient synthesis of carboxyl-linked glucosides and their chemical properties

A facile and efficient synthesis of the carboxyl-linked glucosides of bile acids is described. Direct esterification of unprotected bile acids with 2,3,4,6-tetra-O-benzyl-d-glucopyranose in pyridine in the presence of 2-chloro-1,3,5-trinitrobenzene as a coupling agent afforded a mixture of the α- and β-anomers (ca. 1∶3) of the 1-O-acyl-d-glucoside benzyl ethers of bile acids, which was separated effectively on a C₁₈ reversedphase chromatography column (isolated yields of α- and β-anomers are 4–9% and 12–19%, respectively). Subsequent hydrogenolysis of the α- and β-acyl glucoside benzyl ethers on a 10% Pd−C catalyst in acetic acid/methanol/EtOAc (1∶2∶2, by vol) at 35°C under atmospheric pressure gave the corresponding free esters in good yields (79–89%). Chemical specificities such as facile hydrolysis and transesterification of the acyl glucosides in various solvents were also discussed.     

On the probability theory on MV algebras

 The paper contains a review of some results concerning probability theory on MV algebras (laws of large numbers, central limit theorem, martingale convergence theorem). Also some algebraic and methodical aspects are discussed.     

WO3/BiVO4 composite photoelectrode prepared by improved auto-combustion method for highly efficient water splitting

We report on the improvement in the water splitting efficiency of a WO₃/BiVO₄ composite photoelectrode by the application of an improved auto-combustion method to the preparation of porous BiVO₄ thin films. The unique feature of this preparation method is the addition of both NH₄NO₃, as a strong oxidizing agent, and an organic additive into BiVO₄ precursor solution. The local decomposition heat of the organic additive and oxidizing agent created a porous film with small, highly crystalline BiVO₄ particles. The photoelectrode has many advantages over existing ones, such as the high light-harvesting efficiency (LHE), a single BiVO₄ phase, the facile access of the holes to the photoelectrode/electrolyte interface, and the ease of water and oxygen diffusion. The maximum incident photon-to-current efficiency (IPCE) was estimated to be 64% (at 440 nm, 1.23 V vs. RHE) and the applied bias photon-tocurrent efficiency (ABPE) reached as high as 1.28%. This ABPE value is highest among all oxide semiconductor photoelectrodes reported previously, except for the case of a stacking photoelectrode system.     

Enhanced production of hydroxymethylfurfural from fructose with solid acid catalysts by simple water removal methods

This paper demonstrates two simple ways to increase 5-hydroxymethylfurfural (HMF) yield (selectivity) in fructose dehydration with various solid acid catalysts. One is a water removal from the reaction mixture by a mild evacuation at 0.97 × 10⁵ Pa; it increases HMF yield for various catalysts (heteropoly acid, zeolite, and acidic resin). The removal of water suppresses two undesired reactions: the hydrolysis of HMF to levulinic acid and the reaction of partially dehydrated intermediates to condensation products. The other method is a decrease in the particle (bead) size of the resin (Amberlyst-15). The crushed and sieved Amberlyst-15 powder in a size of 0.15–0.053 mm shows 100% HMF yield at high fructose concentration (50 wt.% in DMSO), which is to our knowledge the highest yield to date. Near-infrared spectroscopic characterization of adsorbed water suggests that the enhanced yield can be caused by an improved removal of adsorbed water in a small-size resin particle.     

Evaluation of selective plating media for the detection of heat- or freeze-injured Staphylococcus aureus

The efficacy of Baird-Parker (BP) agar, mannitol-salt-egg yolk (MSEY) agar and mannitol salt (MS) agar in detecting Staphylococcus aureus FRI-100 heated at 52 degrees C for 20 min in 100 mmol/L potassium phosphate buffer was determined. Brain heart infusion agar with 1% pyruvate (BHIP agar) supported the highest recovery of injured cells and was used as the control medium. Of the three selective media, significantly higher recovery of heat-injured cells was observed on BP agar than MSEY agar, and the poorest recovery was observed on MS agar (p < 0.05). Low recovery of unheated cells was obtained for MS compared with other media (p < 0.05). A reduction in populations occurred gradually in reagent-grade water stored for 14 days at -20 degrees C. There was no significant difference between BHIP agar and MS agar in the number of freeze-injured cells recovered from 1 to 14 days.     

PACVD-Beschichtung von Druckgußwerkzeugen unter ökonomischen und ökologischen Gesichtspunkten

Application of Wear Resistant PACVD-Coatings in Aluminium Diecasting under Economical and Ecological Aspects Aluminium pressure diecasting is a frequently applied manufacturing process for the near netshape production of precision parts. State of the art production techniques still demand considerable amounts of die lubricants. But the side effects of these lubricants include a decrease in surface quality of the cast part as well as a prolongation of the casting cycle time. The job quality decreases and the waste and exhaust disposal during production and application of lubricants is ecologically risky. In this study different wear resistant coating systems have been developed in order to minimize the use of die lubricants in the casting process while at the same time increasing the service life of the diecasting tools. Nitrides, carbides and borides of titanium were synthesized by means of DC-pulse-PACVD. The influence of the process parameters gas composition, pressure, voltage and pulse/pulse repetition ratio was investigated. Compositional analysis was performed by analytical methods such as XRD, EDS, WDS and SIMS. Hardness, adhesion and friction behaviour of the layers were determined in order to describe their mechanical properties. The wetting angle was determined and the corrosion resistance was evaluated in dip tests in aluminium melt. A selection of the best coatings was then compared in diecasting praxis tests under tightened-up conditions reducing the amount of lubricants. TiN, Ti(B,N), TiC and multilayers of the system Ti-C-N were deposited exhibiting a wide range of stoichiometry. The coatings reached hardness values of up to 4400 HK0.005 and the friction coefficient μ was in the range of 0.3. In the diecasting praxis test the amount of die lubricant could be reduced by 97%. Under most severe conditions all layer types led to a minimum increase in the lifetime of the tool of factor 60 compared to an untreated dummy. A strong dependence on the layer type and on its stoichiometry could be observed. Ti(B,N) as the most successful coating in this study has not yet shown any sign of failure and already achieved an increase in lifetime of 300 times.