Site occupancy and annealing behavior of helium in high purity copper

High purity copper has been cyclotron-irradiated with alpha particles to inject roughly 200 at ppm helium. Changes in the lattice parameter due to the helium injection and subsequent isochronal annealing are reported and discussed in terms of the site occupancy of atomic helium and precipitation to form bubbles. The results are interpreted in terms of an earlier model in which the injected helium is present as a stable defect consisting of two or more helium atoms in a single vacant lattice site.     

Designer deletion strains derived from Saccharomyces cerevisiae S288C: a useful set of strains and plasmids for PCR-mediated gene disruption and other applications

A set of yeast strains based on Saccharomyces cerevisiae S288C in which commonly used selectable marker genes are deleted by design based on the yeast genome sequence has been constructed and analysed. These strains minimize or eliminate the homology to the corresponding marker genes in commonly used vectors without significantly affecting adjacent gene expression. Because the homology between commonly used auxotrophic marker gene segments and genomic sequences has been largely or completely abolished, these strains will also reduce plasmid integration events which can interfere with a wide variety of molecular genetic applications. We also report the construction of new members of the pRS400 series of vectors, containing the kanMX, ADE2 and MET15 genes.     

Applications of advanced oxidation processes: present and future.

The use of advanced oxidation processes (AOPs) to remove pollutants in various water treatment applications has been the subject of study for around 30 years. Most of the available processes (Fenton reagent, O3 under basic conditions, O3/H2O2, O3/UV, O3/solid catalyst, H2O2/M(n+), H2O2/UV, photo-assisted Fenton, H2O2/solid catalyst, H2O2/NaClO, TiO2/UV etc.) have been investigated in depth and a considerable body of knowledge has been built up about the reactivity of many pollutants. Various industrial applications have been developed, including ones for ground remediation (TCE, PCE), the removal of pesticides from drinking water, the removal of formaldehyde and phenol from industrial waste water and a reduction in COD from industrial waste water. The development of such AOP applications has been stimulated by increasingly stringent regulations, the pollution of water resources through agricultural and industrial activities and the requirement that industry meet effluent discharge standards. Nevertheless, it is difficult to obtain an accurate picture of the use of AOPs and its exact position in the range of water treatment processes has not been determined to date. The purpose of this overview is to discuss those processes and provide an indication of future trends.     

Thyroid cancers

We have analysed factors that influenced on the patient survival in 195 cases of thyroid cancer. The survival is essentially influenced by the histology, the papillary forms (survival after 15 years: 83.1-93%) and follicular cancers (survival after 15 years: 84-94%) having an excellent evolution. The non-differentiated and mixed cancers have a very severe prognosis that is independent of the complex therapy that have been used (survival after 5 years: 17.1% in non-differentiated forms and 32.5% in mixed ones). The prognosis is better in subjects under the age of 45 and in female subjects. The cancers in the 1-st and 2-nd stage of tumor extension have a better evolution that those in the 3-rd stage. In differentiated cancers, the total or subtotal thyroidectomy followed by radioiodine administration determine the best survival.     

A free energy functional for thermorheologically simple materials

Summary A systematic procedure developed byColeman for establishing thermodynamically consistent constitutive equations is used to develop the thermomechanical constitutive equations for the stress and dissipation functions for thermoheologically simple materials. A comparison is made with similar expressions developed using phenomenological model theory. The influence of thermorheologically simple behavior is illustrated in the solution of the problem of a solid rod undergoing torsional oscillations with temperature dependent properties.

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Eine Darstellung der freien Energie thermorheologisch-einfacher Werkstoffe

Zusammenfassung Eine vonColeman entwickelte systematische Methode zur Aufstellung thermodynamisch konsistenter Werkstoffgleichungen wird zur Bestimmung der Werkstoffgleichungen für Spannungsund Dissipationsfunktion thermorheologisch-einfacher Werkstoffe verwendet. Ein Vergleich mit ähnlichen Ausdrücken phänomenologischer Theorien wird durchgeführt. An Hand der Lösung des Problems eines Torsionsschwingers mit temperaturabhängigen Werkstoffeigenschaften wird der Einfluß des thermorheologisch-einfachen Verhaltens erläutert.

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With 3 Figures     

High-contrast plasma-electrode Pockels cell

A plasma-electrode Pockels cell (PEPC) has been developed for use on the OMEGA extended performance (EP) laser system that can be used in a high-contrast optical switch, as required for isolation of the system from retroreflected pulses. Contrast ratios reliably exceeded 500:1 locally everywhere in the clear aperture. The key to achieving this improvement was the use of circular windows simply supported on compliant O rings, which is shown to produce very low stress-induced birefringence despite vacuum loading. Reliable operation was achieved operating at a relatively high operating pressure, low operating pressures being found to be strongly correlated to occurrences of local loss of plasma density.     

剪切下交联研究

研究剪切下交联情况，将交联过程描述为4个连续阶段，最后一阶段得到均匀分散的微凝胶颗粒，低毒交联体系（聚丙烯酰胺共聚物/Al^3 ）的实验结果证明，交联剂浓度，pH值，流变仪狭缝大小和剪切速率等因素对交联时间和凝胶的最终剪切黏度等理化性能都有影响，通过控制合适的剪切条件，可以制备新型分散凝胶体系。     

A Weighted Nearest Neighbor Algorithm for Learning with Symbolic Features

In the past, nearest neighbor algorithms for learning from examples have worked best in domains in which all features had numeric values. In such domains, the examples can be treated as points and distance metrics can use standard definitions. In symbolic domains, a more sophisticated treatment of the feature space is required. We introduce a nearest neighbor algorithm for learning in domains with symbolic features. Our algorithm calculates distance tables that allow it to produce real-valued distances between instances, and attaches weights to the instances to further modify the structure of feature space. We show that this technique produces excellent classification accuracy on three problems that have been studied by machine learning researchers: predicting protein secondary structure, identifying DNA promoter sequences, and pronouncing English text. Direct experimental comparisons with the other learning algorithms show that our nearest neighbor algorithm is comparable or superior in all three domains. In addition, our algorithm has advantages in training speed, simplicity, and perspicuity. We conclude that experimental evidence favors the use and continued development of nearest neighbor algorithms for domains such as the ones studied here.