超超临界机组锅炉用不锈钢管表面冷作硬化处理对其抗蒸汽氧化性能的影响

通过对一组运行了4年的不锈钢过热器管样内表面机加工区和非机加工区氧化皮的结构和形貌特征进行对比分析,探讨内表面冷作硬化处理对于超超临界机组锅炉用不锈钢管蒸汽氧化性能的影响.结果表明,内表面冷作硬化处理对于改善细晶TP347H FG和Super304奥氏体不锈钢在相对较低温度蒸汽中的抗氧化性能非常有效,但在600℃左右高温蒸汽中Super304管样内表面冷作硬化效应消失,除冷作硬化试样氧化皮的总体厚度略薄外,氧化皮的结构形貌特征与未冷作硬化处理的管样没有多大区别.另外,含Cr量大于22%的SAVE25具有非常优秀的抗蒸汽氧化性能,其机加工区域和未机加工区域的蒸汽氧化行为没有任何区别.     

Generating experimental designs involving control and noise variables using genetic algorithms

Efficient estimation of response variables in a process is an important problem that requires experimental designs appropriated for each specific situation. When we have a system involving control and noise variables, we are often interested in the simultaneous optimization of the prediction variance of the mean (PVM) and the prediction variance of the slope (PVS). The goal of this simultaneous optimization is to construct designs that will result in the efficient estimation of important parameters. We construct new computer‐generated designs using a desirability function by transforming PVM and PVS into one desirability value that can be optimized using a genetic algorithm. Fraction of design space (FDS) plots are used to evaluate the new designs and six cases are discussed to illustrate the procedure. Copyright © 2009 John Wiley & Sons, Ltd.     

Steam oxidation of X20CrMoV121: Comparison of laboratory exposures and in situ exposure in power plants

X20CrMoV121 is a 12% Cr martensitic steel which has been used in power plants in Europe for many decades. Specimens have been removed from superheater tubes to investigate long‐term exposure with respect to steam oxidation. These tubes have been exposed for various durations up to 135 000 h in power plants in Denmark at steam temperatures varying from 450–565 °C. This paper collates the data, compares oxide morphologies and assesses to what extent parabolic kinetics can be used to describe the oxidation rate. The steam oxidation behaviour has been investigated in the laboratory in an Ar‐46%H₂O mixture at 500, 600 and 700 °C for 336 h. It was observed that the morphology of the oxide layers was strongly influenced by temperature, and some of the same morphologies are also observed for power plant specimens. However, the temperatures at which they occur were different for plant and laboratory specimens, e.g. the presence of Cr rich bands within the oxide occurred at a lower temperature in the plant than in the laboratory. In addition there is a greater variety of oxide morphologies for long‐term plant specimens compared to laboratory specimens.     

Identity and spirituality: A psychosocial exploration of the sense of spiritual self.

The authors examined the structure and content of adults' sense of spiritual identity by analyzing semistructured interviews with 13 spiritually devout men and 15 devout women, ages 22 to 72. Individuals' responses to the Role-Related Identity Interview (G. T. Sorell, M. J. Montgomery, & N. A. Busch-Rossnagel, 1997b) were content analyzed and rated on the role-related spiritual identity dimensions of role salience and flexibility. Individuals were categorized as spiritually foreclosed, achieved, or in moratorium, on the basis of their motivational, affective, self-evaluative, and behavioral investments in spiritually defined roles and their reflectiveness about and behavioral changes in role-related spiritual identity. Similarities and differences within and between spiritual identity status groups were observed, suggesting a variety of ways that spiritual identity provides a sense of continuity as well as a domain for adult developmental change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Folding pathway of a lattice model for proteins

The folding of a protein-like heteropolymer is studied by using direct simulation of a lattice model that folds rapidly to a well-defined "native" structure. The details of each molecular folding event depend on the random initial conformation as well as the random thermal fluctuations of the polymer. By analyzing the statistical properties of hundreds of folding events, a classical folding "pathway" for such a polymer is found that includes partially folded, on-pathway intermediates that are shown to be metastable equilibrium states of the polymer. These results are discussed in the context of the "classical" and "new" views of folding.     

Kinematic data on primate head and neck posture: implications for the evolution of basicranial flexion and an evaluation of registration planes used in paleoanthropology

Kinematic data on primate head and neck posture were collected by filming 29 primate species during locomotion. These were used to test whether head and neck posture are significant influences on basicranial flexion and whether the Frankfurt plane can legitimately be employed in paleoanthropological studies. Three kinematic measurements were recorded as angles relative to the gravity vector, the inclination of the orbital plane, the inclination of the neck, and the inclination of the Frankfurt plane. A fourth kinematic measurement was calculated as the angle between the neck and the orbital plane (the head-neck angle [HNA]). The functional relationships of basicranial flexion were examined by calculating the correlations and partial correlations between HNA and craniometric measurements representing basicranial flexion, orbital kyphosis, and relative brain size (Ross and Ravosa [1993] Am. J. Phys. Anthropol. 91:305-324). Significant partial correlations were observed between relative brain size and basicranial flexion and between HNA and orbital kyphosis. This indicates that brain size, rather than head and neck posture, is the primary influence on flexion, while the degree of orbital kyphosis may act to reorient the visual field in response to variation in head and neck posture. Regarding registration planes, the Frankfurt plane was found to be horizontal in humans but inclined in all nonhuman primates. In contrast, nearly all primates (including humans) oriented their orbits such that they faced anteriorly and slightly inferiorly. These results suggest that for certain functional craniometric studies, the orbital plane may be a more suitable registration plane than Frankfurt "Horizontal."     

Cultural factors related to the peer review of teaching

Since 1994, the American Association for Higher Education Peer Review of Teaching Project has sought to popularize the notion that teaching is both a scholarly activity and community property to be shared with and critiqued by the larger academic community. In order to accomplish these goals, each of the three academic units at the twelve participating universities developed a pilot project that conformed to its own institutional, academic unit, and disciplinary culture. At a large Midwestern university, the academic units of mathematics, history, and nursing developed different projects. Each of these projects took account of the unit's specific culture, and this fact helps to account, in large part, for each project's success.     

A Mg(2+)-dependent endonuclease is responsible for internucleosomal DNA fragmentation in human B lymphoblastic IM9 cells

We have identified a Mg(2+)-dependent endonuclease activity from human B lymphoblastic IM9 cell lysates and nuclei using autodigestion method and DNA-native-polyacrylamide gel electrophoresis (DNA-native-PAGE) nuclease assay system. The level of the endonuclease activity in cell lysates was significantly decreased at certain stage by treatment of the cells with cycloheximide. However, the enzyme activity consistently remained for over 12 hours in the isolated nuclei of the apoptotic IM9 cells. The Mg(2+)-dependent endonuclease isolated from the nuclei by native-PAGE elution was able to catalyze the conversion of supercoiled plasmid DNA into linear form. This particular endonuclease activity was not detected in cycloheximide treated-U937 cells. Several lines of experimental evidence suggest that the Mg(2+)-dependent endonuclease localized in the nucleus may be responsible for the DNA fragmentation of apoptotic IM9 cells.