热退火对分子束外延生长的高纯GaAs薄膜中深能级的影响

于2010-11-23批量导入

经典过垒模型在Xe~(q+) +He碰撞中的应用

采用位置灵敏探测和飞行时间技术研究了高电荷态Xe离子 (q =15 ,17,19,2 1,2 3)与He原子碰撞中双电子转移截面与单俘获截面比随入射离子电荷态的变化规律。提出一步过程假定 ,对扩展的经典过垒(ECB)模型进行了修正 ,利用修正模型计算得到的单、双电子转移绝对截面与Andersson等人和Selberg等人的实验结果符合得很好 ,所得截面比与本实验得到的双电子转移截面与单电子俘获截面符合得比较好。

高电荷态Xe离子与He原子碰撞中的电子转移过程研究

采用位置灵敏探测和飞行时间技术研究了高电荷态Xe离子 (q =1 5 ,1 7,1 9,2 1 ,2 3)与He原子碰撞中双电子转移截面与单电子转移截面比随入射离子电荷态的变化规律 .提出一步过程假定 ,对扩展的经典过垒 (ECB)模型进行了修正 ,利用修正模型计算得到的单、双电子转移绝对截面与Andersson等人和Selberg等人的实验结果很好符合 ,所得截面比与本实验得到的双电子转移截面与单电子俘获截面比较好符合

Simulations to design an online motion compensation system for scanned particle beams

Respiration-induced target motion is a major problem in intensity-modulated radiation therapy. Beam segments are delivered serially to form the total dose distribution. In the presence of motion, the spatial relation between dose deposition from different segments will be lost. Usually, this results in over-and underdosage. Besides such interplay effects between target motion and dynamic beam delivery as known from photon therapy, changes in internal density have an impact on delivered dose for intensity-modulated charged particle therapy. In this study, we have analysed interplay effects between raster scanned carbon ion beams and target motion. Furthermore, the potential of an online motion strategy was assessed in several simulations. An extended version of the clinical treatment planning software was used to calculate dose distributions to moving targets with and without motion compensation. For motion compensation, each individual ion pencil beam tracked the planned target position in the lateral aswell as longitudinal direction. Target translations and rotations, including changes in internal density, were simulated. Target motion simulating breathing resulted in severe degradation of delivered dose distributions. For example, for motion amplitudes of +/- 15 mm, only 47% of the target volume received 80% of the planned dose. Unpredictability of resulting dose distributions was demonstrated by varying motion parameters. On the other hand, motion compensation allowed for dose distributions for moving targets comparable to those for static targets. Even limited compensation precision (standard deviation similar to 2 mm), introduced to simulate possible limitations of real-time target tracking, resulted in less than 3% loss in dose homogeneity.

Computational Consequences of Agreement and Ambiguity in Natural Language

The computer science technique of computational complexity analysis can provide powerful insights into the algorithm-neutral analysis of information processing tasks. Here we show that a simple, theory-neutral linguistic model of syntactic agreement and ambiguity demonstrates that natural language parsing may be computationally intractable. Significantly, we show that it may be syntactic features rather than rules that can cause this difficulty. Informally, human languages and the computationally intractable Satisfiability (SAT) problem share two costly computional mechanisms: both enforce agreement among symbols across unbounded distances (Subject-Verb agreement) and both allow ambiguity (is a word a Noun or a Verb?).

Computational Structure of GPSG Models: Revised Generalized Phrase Structure Grammar

The primary goal of this report is to demonstrate how considerations from computational complexity theory can inform grammatical theorizing. To this end, generalized phrase structure grammar (GPSG) linguistic theory is revised so that its power more closely matches the limited ability of an ideal speaker--hearer: GPSG Recognition is EXP-POLY time hard, while Revised GPSG Recognition is NP-complete. A second goal is to provide a theoretical framework within which to better understand the wide range of existing GPSG models, embodied in formal definitions as well as in implemented computer programs. A grammar for English and an informal explanation of the GPSG/RGPSG syntactic features are included in appendices.

The impact of interconnectedness in a triadic relationship between a financial services provider, IFAs, and customers.

The aim of this study is to investigate the impact of interconnectedness between a long-term savings and investments provider, Independent Financial Advisers (IFAs) and customers. Ritter’s (2000) framework of the effect of interconnectedness was used to analyse this triadic relationship. Conceptual studies of triadic business relationships are scarce in marketing and organisational research (Blakenburg & Johanson, 1992; Havila, Johnson & Thilenius, 2004; Ritter, 2000). However, the applicability of a triadic relationship has been tested in a number of case studies (Andersson & Mattsson, 2004; Cunningham & Pyatt, 1989; Jaaskelainen, Kuivalainen & Saarenketo, 2000; Narayandas, 2002; Odorici & Corrado, 2004; Pardo & Salle, 1994; Trimachi, 2002). This study was conducted in collaboration with one of the UK’s largest long-term savings and investments providers. A substantial proportion of the provider’s business is conducted through IFAs and thus their significance as a major stakeholder. Indeed, the majority of sales in the long-term savings and investments industry in the UK are realised through IFAs. Academic studies (Gough, 2005; Gough & Nurullah, 2009) have indicated that IFAs are the strongest distribution channel in the industry. Thus, by analysing the impact of the interconnectedness in this relationship, a strategy that can increase the relationship performance can be proposed. However, to the best of the authors’ knowledge, a study that investigates the effect of the interconnectedness in this triadic relationship has not been established. In addition, the regulatory environment which continues to face change such as the recent implementation of Retail Distribution Review (RDR) on 1st January 2013 will make the relationship more rather than less complex.

Effects of High Dissolved Inorganic and Organic Carbon Availability on the Physiology of the Hard Coral Acropora millepora from the Great Barrier Reef

Coral reefs are facing major global and local threats due to climate change-induced increases in dissolved inorganic carbon (DIC) and because of land-derived increases in organic and inorganic nutrients. Recent research revealed that high availability of labile dissolved organic carbon (DOC) negatively affects scleractinian corals. Studies on the interplay of these factors, however, are lacking, but urgently needed to understand coral reef functioning under present and near future conditions. This experimental study investigated the individual and combined effects of ambient and high DIC (pCO2 403 μatm/ pHTotal 8.2 and 996 μatm/pHTotal 7.8) and DOC (added as Glucose 0 and 294 μmol L-1, background DOC concentration of 83 μmol L-1) availability on the physiology (net and gross photosynthesis, respiration, dark and light calcification, and growth) of the scleractinian coral Acropora millepora (Ehrenberg, 1834) from the Great Barrier Reef over a 16 day interval. High DIC availability did not affect photosynthesis, respiration and light calcification, but significantly reduced dark calcification and growth by 50 and 23%, respectively. High DOC availability reduced net and gross photosynthesis by 51% and 39%, respectively, but did not affect respiration. DOC addition did not influence calcification, but significantly increased growth by 42%. Combination of high DIC and high DOC availability did not affect photosynthesis, light calcification, respiration or growth, but significantly decreased dark calcification when compared to both controls and DIC treatments. On the ecosystem level, high DIC concentrations may lead to reduced accretion and growth of reefs dominated by Acropora that under elevated DOC concentrations will likely exhibit reduced primary production rates, ultimately leading to loss of hard substrate and reef erosion. It is therefore important to consider the potential impacts of elevated DOC and DIC simultaneously to assess real world scenarios, as multiple rather than single factors influence key physiological processes in coral reefs.

Recovering a lost inheritance : The marital economy and its absence from the Prehistory of Economics in Britain

Roberts, Michael. 'Recovering a lost inheritance: the marital economy and its absence from the Prehistory of Economics in Britain', in: 'The Marital Economy in Scandinavia and Britain 1400-1900', (Eds) Argen, Maria., Erickson, Amy Louise., Farnham: Ashgate, 2005, pp.239-256 RAE2008

Det individuella möter det kollektiva. Självbiografiskt stoff i barndomsskildringar från det svenska folkhemmet

The subject of the article are autobiographical threads present in Swedish stories about childhood and adolescence published after 1986 that form part of the narrative pertaining to the origins, evolution and decline of the Swedish welfare state (folkhemmet). With reference to such concepts as autobiographical pact, autobiographical novel and auto-fiction, the author discusses the various ways six contemporary Swedish writers (PC Jersild, Kjell Johansson, Susanna Alakoski, Jonas Gardell and Lena Andersson) use their biographies. Special focus is given to the notion of how a cogitation upon individual fate becomes universal when placed in a social context. Another problem analysed by the author is the significance of autobiographical threads for building relationships between the writer and the reader and for the reception of a literary text.

Comparative evaluation of serologic tests for celiac disease: a European initiative toward standardization.

BACKGROUND: Serologic methods have been used widely to test for celiac disease and have gained importance in diagnostic definition and in new epidemiologic findings. However, there is no standardization, and there are no reference protocols and materials. METHODS: The European working group on Serological Screening for Celiac Disease has defined robust noncommercial test protocols for immunoglobulin (Ig)G and IgA gliadin antibodies and for IgA autoantibodies against endomysium and tissue transglutaminase. Standard curves were linear in the decisive range, and intra-assay variation coefficients were less than 5% to 10%. Calibration was performed with a group reference serum. Joint cutoff limits were used. Seven laboratories took part in the final collaborative study on 252 randomized sera classified by histology (103 pediatric and adult patients with active celiac disease, 89 disease control subjects, and 60 blood donors). RESULTS: IgA autoantibodies against endomysium and tissue transglutaminase rendered superior sensitivity (90% and 93%, respectively) and specificity (99% and 95%, respectively) over IgA and IgG gliadin antibodies. Tissue transglutaminase antibody testing showed superior receiver operating characteristic performance compared with gliadin antibodies. The K values for interlaboratory reproducibility showed superiority for IgA endomysium (0.93) in comparison with tissue transglutaminase antibodies (0.83) and gliadin antibodies (0.82 for IgG, 0.62 for IgA). CONCLUSIONS: Basic criteria of standardization and quality assessment must be fulfilled by any given test protocol proposed for serologic investigation of celiac disease. The working group has produced robust test protocols and reference materials available for standardization to further improve reliability of serologic testing for celiac disease.

Guidelines on the standards for the training of specialised health professionals dealing with breast cancer.

According to EUSOMA position paper 'The requirements of a specialist breast unit', each breast unit should have a core team made up of health professionals who have undergone specialist training in breast cancer. In this paper, on behalf of EUSOMA, authors have identified the standards of training in breast cancer, to harmonise and foster breast care training in Europe. The aim of this paper is to contribute to the increase in the level of care in a breast unit, as the input of qualified health professionals increases the quality of breast cancer patient care.

Flexible and robust run-time configuration for self-managing systems

This paper describes a methodology for deploying flexible dynamic configuration into embedded systems whilst preserving the reliability advantages of static systems. The methodology is based on the concept of decision points (DP) which are strategically placed to achieve fine-grained distribution of self-management logic to meet application-specific requirements. DP logic can be changed easily, and independently of the host component, enabling self-management behavior to be deferred beyond the point of system deployment. A transparent Dynamic Wrapper mechanism (DW) automatically detects and handles problems arising from the evaluation of self-management logic within each DP and ensures that the dynamic aspects of the system collapse down to statically defined default behavior to ensure safety and correctness despite failures. Dynamic context management contributes to flexibility, and removes the need for design-time binding of context providers and consumers, thus facilitating run-time composition and incremental component upgrade.

Scalable and efficient graph colouring in 3 dimensions using emergence engineering principles

This paper describes ways in which emergence engineering principles can be applied to the development of distributed applications. A distributed solution to the graph-colouring problem is used as a vehicle to illustrate some novel techniques. Each node acts autonomously to colour itself based only on its local view of its neighbourhood, and following a simple set of carefully tuned rules. Randomness breaks symmetry and thus enhances stability. The algorithm has been developed to enable self-configuration in wireless sensor networks, and to reflect real-world configurations the algorithm operates with 3 dimensional topologies (reflecting the propagation of radio waves and the placement of sensors in buildings, bridge structures etc.). The algorithm’s performance is evaluated and results presented. It is shown to be simultaneously highly stable and scalable whilst achieving low convergence times. The use of eavesdropping gives rise to low interaction complexity and high efficiency in terms of the communication overheads.

Models of advertising standardisation and adaptation: it's time to move the debate forward

Advertising standardisation versus adaptation has been discussed in some detail in the marketing literature. Despite previous attempts, there is still no widely-used decision-making model available that has been accepted by marketing practitioners and academics. This paper examines the development of this important area by reviewing six prominent models in the advertising standardisation/adaptation literature. It shows why there has been a lack of development in the current literature and why it is crucial to address this problem. Important areas for future research are suggested in order to find a solution