Doped silicon under uniaxial tensile strain investigated by PAC

The recent application of strained silicon into transistor design has led to significant progress in increasing the performance of devices. However, up to now little is known about the mechanical behaviour of the strained Si layers and the elastic properties of the deformed semiconductor lattice. The perturbed angular correlation method is ideally suited to study strain related local phenomena in silicon using the acceptor ¹¹¹In as probe. In the past, the influence of external uniaxial strain on In acceptors in pure Si and on donor-acceptor pairs in silicon has been investigated intensively (G. Marx, R. Vianden, Phys. Lett. A210, 364 1996; G. Tessema, PhD thesis, University of Bonn, 2003). In the course of these studies it was found that the unpaired indium probes on regular lattice sites showed an unexpected reaction to uniaxial strain, which depended on the dopant species. Our current experiments reveal that the tension induced local deformation around the In probe atoms also depends on the concentration of the co-implanted donors suggesting a local change of the elastic properties of silicon. In addition, the reaction of the silicon lattice to tensile strain applied along different crystal axes showed strong differences.     

Simplified correlation models for CO/H2 chemical reaction times

This paper provides simplified correlation models for CO/H₂ chemical reaction times. The procedure used for the CO/H₂ simplified modeling utilized the full chemical kinetics mechanism run over a range of temperatures from 700 to 1800 K, pressures from 0.5 to 50 atm, mixtures from 0% to 95% CO, and equivalence ratios from 0.2 to 2.0 to determine ignition (or reaction) time. The correlations for ignition times are given in formulas as functions of equivalence ratio, temperature, and pressure. Two different forms of correlations were obtained, one being a single, overall correlation and the other a two-stage correlation representing regions of high and low temperatures. These correlations are shown to work well over a range of chemical time scales spanning ten orders of magnitude. The correlations are also compared with measured data from the literature.     

包装行业教育的未来

作为战略因素的包装工业 近年来,整个包装工业的地位突然有了巨大的提高,尤其是在亚洲,如中国.     

Electron probe analysis of microdroplets: Factors affecting the proportionality between measured X-ray intensity and concentration

Factors liable to limit the validity of liquid sample analysis by electron microprobe are investigated. For lyophilized samples composed of large 2–6 μm crystals, linear calibration curves may still be obtained for Na, Mg, P, Cl, K and Ca by raising the accelerating voltage to 18 kV, provided the X-ray take-off angle of the electron microprobe is 40°. Routinely prepared lyophilized samples are composed of discrete crystals. Their size is reproducible, depending on the composition of the dried deposit, and ranges from 0.1 to 0.5 μm for deposits mainly composed of NaCl. Within this range, the proportionality of X-ray intensity to concentration is not affected by particle size. The concentration range for which X-ray intensities remain proportional to concentrations is experimentally determined for the six elements above as a function of sample mass thickness and accelerating voltage. For certain elements, the proportionality constant is shown to vary with the composition of the solution. As regards chlorine concentration determinations, analysis of plasma ultrafiltrate and recovery experiments suggest that the proportionality constant is definitely 10% higher for this ultrafiltrate than for standard solutions.     

Optimisation d’un guide d’onde de silicium sur saphir pour l’observation de la bistabilité optique

A silicon on sapphire nonlinear waveguide which can be used for all-optical logic operation is described. A theoretical analysis confirms that the fast switchings experimentally observed using this device result from a competition between electronic and thermal nonlinear effects occurring in silicon. Numerical simulations display the influence of various parameters on the device operation conditions as an optical switch or bistable device.     

Cognitive—behavioral treatment of obsessive thoughts: A controlled study.

Twenty-nine patients with obsessive-compulsive disorder as diagnosed in accordance with the Diagnostic and Statistical Manual of Mental Disorders (3rd ed., revised; American Psychiatric Association, 1987) who did not have overt compulsive rituals were randomly assigned to treatment and waiting-list conditions. Patients in the treatment condition received cognitive-behavioral therapy consisting of a detailed explanation of the occurrence and maintenance of obsessive thoughts, exposure to obsessive thoughts, response prevention of all neutralizing strategies, cognitive restructuring, and relapse prevention. Compared with waiting-list patients, treated patients improved significantly on measures of severity of obsessions, current functioning, self-report obsessive-compulsive symptoms, and anxiety. When waiting-list patients were subsequently treated, the combined group improved on all outcome measures. Treatment gains were maintained at 6-month follow-up. Results indicate that cognitive-behavioral therapy is effective in the treatment of patients with obsessive thoughts, a group that has often been considered resistant to treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An interface to a reliable packet delivery service for parallelsystems

Modern distributed memory parallel computers provide hardware support for the efficient and reliable delivery of interprocessor messages. This facility needs to be accessed by lightweight protocols that do not waste the performance of the underlying hardware; the heavyweight layering techniques traditionally used in distributed systems are wholly inappropriate. A low-level communication interface is therefore presented which exploits modern architectures effectively, while maintaining a good match to existing parallel programming environments. The interface defines mechanisms to access an asynchronous reliable packet delivery service. It permits messaging protocols to be efficiently synthesized by considering the activity at their end-points alone. This arrangement effectively decouples the implementation of protocols from low-level architectural features, and hence aids the portability of parallel programming environments. Furthermore, the interface allows the communication network to be shared by multiple programming paradigms, giving additional flexibility over existing systems     

Purification and characterization of deep sea sharkCentrophorus squamosus liver oil 1-O-aklylglycerol ether lipids

The 1-O-alkylglycerol composition of the liver oil of the deep sea sharkCentrophorus squamosus, a species which provides edible flesh, has been determined. After various fractionations of the oil, the unsaponifiable fraction was characterized by means of gas chromatography/mass spectrometry, electron impact, and positive-ion chemical ionization. The oil is composed of 60% unsaponifiable matter, containing 45% squalene, 4.5% cholesterol, and 10% of linear saturated and monounsaturated glycerol ethers with 14–18 carbon atoms. After a first separtion by chromatography on silicic acid, monounsaturated glycerol ethers have been separated from the saturated homologues, in particular from 1-O-octadecylglycerol (batyl alcohol) and 1-O-hexadecylglycerol (chimyl alcohol)via urea complexation. This newer application of the urea method, already used in the past to extract saturated from polyunsaturated fatty acids, allowed the purification of the main components of the complex unsaturated glycerol ether fraction, namely, 1-O-octadecen-9′ylglycerol (selachyl alcohol) and 1-O-hexadecen-9′ylglycerol.     

Personality disorders and the outcome of cognitive–behavioural treatment of panic disorder with agoraphobia.

In recent years, cognitive–behavioural interventions have proven to be effective in the treatment of Panic Disorder with Agoraphobia (PDA). However, there is controversy concerning treatment efficacy of PDA for patients with a comorbid diagnosis of Personality Disorder (PD). This study evaluates the impact of a PD on PDA treatment response. 81 patients suffering from PDA were recruited from a cognitive–behavioural group treatment program. Diagnoses on Axis I (N?=?81) and Axis II (N?=?36) were made at treatment onset according to Diagnostic and Statistical Manual of Mental Disorders-III-Revised (DSM-III-R) criteria. Validated questionnaires were used to assess agoraphobia at treatment onset, following treatment, and at the 3 mo follow-up. All patients improved markedly from pretest to posttest and at the 3 mo follow-up. Grouping of patients according to the presence or absence of a personality disorder revealed significant differences between the groups on pre- and posttreatment scores on agoraphobia. Results also reveal that patients with a personality disorder improve more slowly than patients without a personality disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Craze growth in annealed polycarbonate

In a recent paper [5], it was shown that dry polycarbonate craze growth kinetics are compatible with a propagation mechanism based on the creep of craze material. Further confirmation of such a mechanism is found in the lack of variation of crazing kinetics with thermal pretreatment, as opposed to bulk yield stress which is known to vary significantly on annealing.