Characterization and electrochemical properties of CF4 plasma-treated boron-doped diamond surfaces

The effect of CF₄ plasma etching on diamond surfaces, with respect to treatment time, was investigated using scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electrochemical measurements. SEM observations and Raman spectra indicated an increase in surface roughening on a scale of 10–20 nm, and an increase in crystal defect density was apparent with treatment time in the range of 10 s to 30 min. In contrast, alteration of the diamond surface terminations from oxygen to fluorine was found to be rather rapid, with saturation of the F/C atomic ratio estimated from XPS analysis after treatment durations of 1 min and more. The redox kinetics of Fe(CN)₆^3−/4− was also found to be significantly modified after 10 s of CF₄ plasma treatment. This behavior shows that C–F terminations predominantly affect the redox kinetics compared to the effect on the surface roughness and crystal defects. The double-layer capacitance (C_dl) of the electrolyte/CF₄ plasma-treated boron-doped diamond interface was found to show a minimum value at 1 min of treatment. These results indicate that a short-duration CF₄ plasma treatment is effective for the fabrication of fluorine-terminated diamond surfaces without undesirable surface damage.     

Numerical modelling for scattering of waves in three-dimensional cracked material

In this paper, a mathematical model is proposed for the problem of the scattering of plane waves in a three-dimensional cracked materials. Instead of obtaining closed-form solutions as in conventional theoretical analysis methods, this approach, called the Equivalent Nodal Force (ENF) method formulates the mechanical effects of cracks as an equivalent nodal force in a numerical procedure, and physically translates cracked material into an equivalent continuous one. Several mechanical relations between waves and cracks are evident from this method. Also the results of several numerical calculations are presented and these are compared with those obtained by the conventional methods.     

Surface-Chemical Criteria for Optimum Adhesion

According to Bikerman, who attributes failure in adhints to a weak boundary layer, it is almost impossible and meaningless to correlate adhesive strength to surface-chemical properties of adhints. Though his assertion seems to be confirmed by the recent studies of Schonhorn and his coworkers on the methods of CASING and TCR, not a few results have yet been accumulated, which show a close relation between them. In this paper surface-chemical criteria for the optimum adhesion are investigated and the minimum interfacial tension or the maximum wetting pressure is deduced from the published data and our own as a first approximation. It is emphasized that, when critical surface tension γ_c would be used as a measure of surface-chemical properties of solid, its variability according to liquid series (nonpolar, polar and hydrogen bonding liquids) should be carefully taken into consideration. The importance is shown for polyethylene and its fluorine substituted polymers, using newly measured contact angle data and Zisman's data. Results of Levine et al. and Schonhorn et al. on adhesive shear strength with epoxy adhesives are replotted against available values of γ_c obtained by the use of hydrogen bonding liquid (γ_c^c), which are thought to reflect wetting behaviors of epoxy adhesives quite well. Each curve shows a maximum around γ_c^c = 40 dyne/cm with few points falling off the curves.     

Clonality in hepatocellular carcinoma: analysis of methylation pattern of polymorphic X-chromosome-linked phosphoglycerate kinase gene in females

Analysis of X-chromosome inactivation patterns in women has been used to assess the clonality of various tumors. In this report, we analyzed 27 liver tumors in women, including 18 samples obtained by the performance of ultrasonically guided thin-needle biopsies. By analysis of the heterogeneity of phosphoglycerate kinase gene, 11 of 27 (41%) cases were found to be heterozygous at the gene. Of these informative 11 cases with liver tumors, 7 cases were "large" tumors (> 25 mm in diameter) and 4 cases were "small" tumors (< 25 mm in diameter). All 7 large tumors showed monoclonal patterns by the phosphoglycerate kinase gene analysis. Of the 4 small tumors, 2 showed monoclonal, and 2 showed polyclonal patterns. The 2 with monoclonal patterns were pathologically diagnosed as hepatocellular carcinoma despite their small sizes (20 mm and 23 mm). Of the two with polyclonal patterns, the smallest one (15 mm) was diagnosed as benign adenomatous hyperplasia, and the other as hepatocellular carcinoma heavily infiltrated by lymphocytes. These data suggest that analysis of the methylation pattern of the phosphoglycerate kinase gene may be helpful on rare occasions in elucidating the nature of liver tumors but must in fact be used in conjunction with histological appearances to avoid errors secondary to inflammatory infiltrates.     

Stochastic unit commitment problem

The electric power industry is undergoing restructuring and deregulation. We need to incorporate the uncertainty of electric power demand or power generators into the unit commitment problem. The unit commitment problem is to determine the schedule of power generating units and the generating level of each unit. The objective is to minimize the operational cost which is given by the sum of the fuel cost and the start‐up cost. In this paper we propose a new algorithm for the stochastic unit commitment problem which is based on column generation approach. The algorithm continues adding schedules from the dual solution of the restricted linear master program until the algorithm cannot generate new schedules. The schedule generation problem is solved by the calculation of dynamic programming on the scenario tree.     

Linear bipolar OTAs employing exponential‐law circuits

This paper presents design of linear bipolar OTAs, which are composed of two function blocks; one is an exponential‐law circuit and the other is a core cell. Multi‐tanh cells are employed as the core cell. This kind of OTA has lower power dissipation relatively to the conventional multi‐tanh cell. According as the order of the multi‐tanh core cell becomes higher, the number of circuit realization for the core cell increases. For example, we have two OTAs for the core circuit of an emitter‐coupled pair and four OTAs for the doublet core cell. Thus, we consider the generalized OTAs for an arbitrary order n of the core cell and obtain a formula to give the realization number of the linear OTAs for n. According to the formula, there must be eight OTAs in the case of n=3. All of the eight OTAs are examined. Analysis and simulation results show that the OTAs have advantage in their characteristics, such as linear input range, power dissipation, noise, and frequency response. Copyright 2004 John Wiley & Sons, Ltd.     

Schematic Influences on Category Learning and Recognition Memory.

The results from 3 category learning experiments suggest that items are better remembered when they violate a salient knowledge structure such as a rule. The more salient the knowledge structure, the stronger the memory for deviant items. The effect of learning errors on subsequent recognition appears to be mediated through the imposed knowledge structure. The recognition advantage for deviant items extends to unsupervised learning situations. Exemplar-based and hypothesis-testing models cannot account for these results. The authors propose a clustering account in which deviant items are better remembered because they are differentiated from clusters that capture regularities. The function of clusters is akin to that of schemas. Their results and analyses expose connections among research in category learning, schemas, stereotypes, and analogy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predictive Simulation of Deformation and Failure of Peat-Calcareous Soil Layered Ground Due to Multistage Test Embankment Loading

The continuous behaviour of a ground-embankment system from the stage of deformation up to failure was predicted with respect to an actual test embankment that had been constructed in stages on a soft ground made up of peat and calcareous soil. The behaviour prediction was carried out by employing soil-water coupled finite deformation analysis, which also included simulation of the embankment construction process. The information used in the analysis was limited to such things as the results of soil tests on soil materials (peat and calcareous soil) sampled from the ground, including their sensitivity ratios, and the embankment's construction history. The SYS Cam-clay model was used in the constitutive equations of the soils to determine the material constants of the soils and the initial conditions of the ground, and the computations were performed under plane strain conditions. As a result, the computed profiles of W-type ground settlement and of slip surfaces running through the embankment were found to be in good overall agreement with the actual profiles measured at the site. Furthermore, we found that this slippage is attributable to the undrained shear response of the soil elements in the calcareous soil layer, where slippage begins to occur during embankment loading. In other words, the slippage is caused by the rapid softening behaviour caused by the degradation of structure after the effective stress ratio reaches the vicinity of the critical state line.     

Measurement of High-Temperature Elastic Properties of Ceramics Using a Laser Ultrasonic Method

Young's modulus and Poisson's ratio of SiC ceramics at temperatures >1400°C were obtained using a laser ultrasonics method that included a Fabry-Pérot interferometer (LUFP). At temperatures <1000°C, Young's modulus and Poisson's ratio measured using the LUFP method agreed well with those measured using standard contact methods, such as the resonance method and the ultrasonic pulse method. These results showed that the LUFP method is a powerful tool for measuring high-temperature elastic properties of advanced ceramics in a noncontact manner.