Dielectric relaxation of high-k oxides

Frequency dispersion of high-k dielectrics was observed and classified into two parts: extrinsic cause and intrinsic cause. Frequency dependence of dielectric constant (dielectric relaxation), that is the intrinsic frequency dispersion, could not be characterized before considering the effects of extrinsic frequency dispersion. Several mathematical models were discussed to describe the dielectric relaxation of high-k dielectrics. For the physical mechanism, dielectric relaxation was found to be related to the degree of polarization, which depended on the structure of the high-k material. It was attributed to the enhancement of the correlations among polar nanodomain. The effect of grain size for the high-k materials'' structure mainly originated from higher surface stress in smaller grain due to its higher concentration of grain boundary.     

Predicted distribution and ecological risk assessment of a "segregated" hydrofluorrother in the Japanese environment

An assessment of HFE-7500, a 'segregated' hydrofluoroether, was conducted to evaluate the potential for exposure to and subsequent effects on humans and wildlife in Japan. The segregated hydrofluoroethers belong to a class of fluorochemicals currently being proposed as replacements for traditional fluorochemicals (CFCs and PFCs) that are currently being used in several industries, in particular, the semiconductor industry. These traditional compounds have been implicated as ozone-depleting or potent "greenhouse gases". The segregated hydrofluoroethers have useful physical and chemical properties, but do not contribute to ozone depletion and have lower "global warming potential" (GWP) indices. Although the physical properties of these materials (low H2O solubility and high vapor pressure) suggest there would be a very low level of risk to aquatic systems, a thorough analysis had not been previously performed. Predicted environmental concentrations (PECs) of HFE-7500 in Japan were determined with the Higashino model, a Gausian puff and plume model that used an approximation of environmental releases to the atmosphere as input to the model. Allowable concentrations to protect aquatic life, wildlife, and humans from noncancer effects were determined as detailed in USEPA's final Water Quality Guidance for the Great Lakes Systems. Potential risk to ecological receptors and humans was determined by calculating hazard quotients and margins of safety. The results of the risk assessment indicate that HFE-7500 poses no significant risk to either aquatic or terrestrial wildlife species or humans living in the Japanese environment. The least margin of safety for any ecological receptor was 100,000, and a margin of safety greater than 100,000,000 for most receptors indicated that HFE-7500 poses no threat to human health. Because of a scarcity of toxicity and exposure data, the risk assessment was based on very conservative assumptions. Therefore, the actual margins of safety for both humans and wildlife could have been 100- to 1,000-fold greater if additional data were available such that less stringent uncertainty factors could be applied. These results suggest that the environmental impact of HFE-7500 should be inconsequential based on the marked improvement in its atmospheric properties relative to the traditional compounds currently in use. Given the short atmospheric lifetime and low global warming potential of this material, its replacement of CFCs and PFCs would result in a net improvement of environmental health and safety.     

Diffusive partitioning tracer test for nonaqueous phase liquid (NAPL) detection in the vadose zone

This paper proposes the theory and practical application of a new partitioning tracer test for nonaqueous phase liquid (NAPL) detection in the vadose zone, which is based on diffusion. A mixture of chlorofluorocarbons as gaseous tracers is injected into the vadose zone to form a point source at the injection point. While the tracers diffuse away, small volumes of gas are withdrawn from the injection point. The quantitative determination of the NAPL saturation is based on a comparison of the concentration decline of tracers with different air-NAPL partitioning coefficients. The test has been evaluated in laboratory sand columns contaminated with dodecane. NAPL in saturations of 0.8-4% of the total porosity have been quantified in a wide range of different water contents. Actual and measured NAPL saturations calculated as an average from four different tracer pairs agreed within +/-30%. The new method was successfully used for repeated NAPL quantification in a large-scale field lysimeter contaminated with artificial kerosene. This rapid and inexpensive test is potentially of value for site investigations especially in combination with soil gas measurements, because it requires similar equipment. Possible applications are source delineation and repeated NAPL quantification in situ during a remediation.     

The role of the corpus callosum in dichotic listening: A combined morphological and diffusion tensor imaging study.

The objective of the present study was to examine the role of the corpus callosum (CC) in dichotic listening. For this purpose, 40 right-handed healthy male participants were assessed with morphological and diffusion tensor imaging, which yielded macrostructural (midsagittal area) and microstructural (mean diffusion, fractional anisotropy) measures of the total CC and predefined subregions. Applying the standard consonant-vowel Bergen Dichotic Listening Test (including 3 different attentional instructions), the authors found dichotic listening performance to be substantially related to the integrity of the CC at both macro- and microstructural levels. Results indicate a dual role of the CC; it is relevant not only for the stimulus-driven (bottom-up) transfer of left-ear input to the left hemisphere but also for its attentional (top-down) modulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Review of Forms of Intersubjectivity in Infant Research and Adult Attachment.

Reviews the book, Forms of Intersubjectivity in Infant Research and Adult Attachment by Beatrice Beebe, Steven Knoblauch, Judith Rustin, and Dorienne Sorter (2005). In this book, the authors use their 10 years of collaborative work to produce an in-depth and well-constructed discussion of verbal and nonverbal forms of intersubjectivity as observed in the treatment setting and as evidenced by data generated from more mainstream child development studies. They move beyond the lack of integration between these related though often dramatically disconnected disciplines and build on infant researchers' understanding of "prereflective" caregiver-child interactions to offer a new theory of intersubjectivity that enhances our understanding of the clinical interaction with adult patients. This book is not for those therapists who are interested in learning well-specified, new interventions to use in their psychotherapy practice. It is also not suggested for those clinicians who do not have some background in psychoanalytic theory and practice. It is, however, recommended for those clinicians who work psychodynamically and are interested in developing their awareness of the nonverbal aspects of treatment and the co-construction of the therapeutic encounter. This book would also be useful to those in the field of psychotherapy research as it poses new questions about the nature of the therapeutic process and suggests the importance of examining the role that implicit, nonverbal interactions play in psychotherapy. Beebe, Knoblauch, Rustin, and Sorter's book is well constructed, persuasively argued, and highly recommended. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Validation and application of the WABE code: Investigations of constitutive laws and 2D effects on debris coolability

The WABE-2D model aims at the problem of coolability of degraded core material during a severe accident in a light water reactor (LWR) and describes the transient boil-off and quenching behavior of debris beds. It is being developed in the frame of the KESS code system, which is considered to describe the processes of core heatup, melting, degradation and relocation to the lower plenum as well as the subsequent behavior. The models developed in this frame are being integrated in the German system code ATHLET-CD.An emphasis of the present contribution lies on multidimensional aspects of the cooling behavior. From multidimensional features a significant improvement of overall coolability is expected compared to what is concluded based on classical one-dimensional analyses. Such analyses – also mainly oriented at top cooling conditions – additionally miss the expected importance of interfacial drag which should support coolability in co-current flow situations due to bottom flooding. The latter situation plays a role in the multidimensional behavior expected under realistic conditions. Thus, a further emphasis in the present contribution lies on the constitutive drag laws and their effects in such configurations.Calculations comparing top and bottom flooding and the influence of interfacial friction are presented. An explanation for effects observed in related experiments at Forschungszentrum Karlsruhe is provided based on this influence. The significant increase of dryout heat flux with water inflow from below, driven by a lateral water column, is reproduced and understood. Enhanced cooling due to this and in general by lateral inflow is also demonstrated for reactor scenarios, considering particulate debris in the lower head of the reactor pressure vessel (RPV) of a LWR or in a deep water pool in the reactor cavity of a boiling water reactor (BWR). Cooling by steam flow through local dry zones can establish under lateral water supply to regions below and yield a further extension of coolability. Quenching of hot material is also analyzed. Finally, cases with loss of coolability, dry zone formation and melting are considered, especially in the perspective to analyze melt pool formation in the lower head of the RPV and the history of thermal interaction with the lower head wall. The latter will determine failure possibilities and modes of the RPV.     

优化负荷及发电管理

热电系统或水-热电系统的运营商对运营进行长远规划,从而确定自身发电及采用其他可利用能源的供应量,如以合同形式采购能源.该计划的目的是最小化电力系统的运行成本,或最大化利润.     

(Ba,Ca)TiO3 PTCR Ceramics with LaNiO3 Thin-Film Electrodes: Preparation and Characterization of the Interface

Conductive LaNiO₃ thin film electrodes were deposited by chemical solution deposition (CSD) from nitrate solutions onto polycrystalline Al₂O₃ and (Ba,Ca)TiO₃ PTCR ceramic substrates. The electrical properties of the LaNiO₃ thin film on Al₂O₃ and of the interface consisting of LaNiO₃ and the semiconductive oxide ceramic were investigated. The deposited LaNiO₃ films were about 250 nm thick and consisted of nanosized particles. The resistivity of the LaNiO₃ film was about 3 × 10^-3cm at 20°C. The PTCR ceramic consisted of m sized particles and exhibited an electronic resistivity of about 10 cm at 20°C and a steep increase of the resistivity of a few orders of magnitude above the Curie point at about 120°C. The electrical properties of the LaNiO₃/PTCR interface were dominated by the properties of a barrier layer between the PTCR ceramic and the LaNiO₃ electrode. The potential dependence of the impedance indicated that the barrier layer consisted of a depletion layer within the PTCR ceramic, when the flat band potential of LaNiO₃ on the PTCR ceramic at about –250 mV was exceeded. Additionally the formation of an insulating layer at the LaNiO₃ electrode has to be taken into account.