[(t-BuCp)_2PrCl]_2的合成和晶体结构

叔丁基环戊二烯钠和无水三氯化镨在四氢味喃中反应,产物经过甲苯处理,分离得到配合物[(t-BuCp)_2PrCl]_2对该配合物进行了元素分析,红外光谱和~1HNMR表征。同时测得了它的单晶结构。该配体属正交晶系,C_(mca)空间群,晶胞参数为:a=2.378(6)nm,b=0.9565(1)nm,c=1.6455(4)nm,V=3.743nm~3,Z=4。R=0.042。Pr—Cl键长为0.2864nm。Pr-Cent(环中心)为0.2489nm。Pr-Pr(a)为0.4041nm。

钛在草酸溶液中腐蚀行为的XPS研究

本文首次用X-光电子能谱(XPS)技术研究了H_2C_2O_4溶液中钛基的腐蚀行为,对Ti基片的表面和界面进行了XPS表征.实验结果表明:Ti基在80℃,10%的草酸溶液中腐蚀两小时,样品的表面只有Ti~0和TiO存在;经过四小时腐蚀的样品表面主要是TiO_2和少部分Ti~(2+).这与X-衍射分析认为有TiH_(1.042)的结构看法相符。同时,Ti0_2与表面涂层RuO_2都属金红石型结构,因而完全有可能形成牢固的金属阳极材料。

大洋岛屿玄武岩低温蚀变作用及其对大洋过渡金属循环的贡献

用化学方法和ICP—MS方法分别对中、西太平洋海山富钴铁锰结壳产出区玄武岩的主元素、 微量元素和稀土元素(REE)含量进行了测定，结果表明，研究区玄武岩经受了强烈的洋底低温蚀 变作用，主元素成分发生了明显的变化，失去了原岩的特征．样品与新鲜大洋岛屿玄武岩(OIB) 极为相似的稀土元素配分模式和微量元素含量特征表明，所研究的岩石属典型的大洋板内玄武 岩．受洋底低温蚀变作用的影响，样品的Al O。，Fe O。，MnO、K O，P O 含量增加，MgO，FeO 的 含量降低．蚀变作用使大洋岛屿玄武岩中的镁、铁等活动组分大量流失，从而表现出相对富SiO 的特征(标准矿物计算结果中出现石英)． 由于蚀变作用，活动组分的流失使样品的REE相对富 集，而富REE铁锰氧化物在玄武岩气孔和裂隙中的沉淀不仅使样品的REE含量增大，而且引起 轻稀土元素(LREE)与重稀土元素(HREE)分馏，表现为Σf(Ce)／Σf(Yb)值增大． 以REE 富集 机制为基础，对样品中铁锰氧化物的沉淀量和单位质量新鲜玄武岩中活动组分的流失量进行了理 论计算，结果表明，因低温蚀变作用所引起的新鲜玄武岩的单位质量亏损为0．150t0．657，而单 位质量新鲜玄武岩中铁锰氧化物的沉淀量为0．006t0．042．主元素中以铁、镁的流失亏损最为明 显，新鲜玄武岩中铁、镁的流失比例分别为18．28 ～70．95 和44．50％～93．94％ ，超过了岩石 总量的流失亏损比例(15．0 ～65．7 )，因而样品相对贫铁、镁．其他元素的流失量和流失比例 都很好地印证了地球化学研究的结果．样品中铝、钾、磷负的流失量是由于沸石在岩石气孔中的充 填和岩石的磷酸盐化．理论计算结果和地球化学研究都表明，大洋岛屿玄武岩的低温蚀变向海水 提供了大量金属，这是大洋海水中金属循环的重要环节．

Extracted Memory from Temporal Patterns Using Adaptive Resonance and Recurrent Network

We can recognize objects through receiving continuously huge temporal information including redundancy and noise, and can memorize them. This paper proposes a neural network model which extracts pre-recognized patterns from temporally sequential patterns which include redundancy, and memorizes the patterns temporarily. This model consists of an adaptive resonance system and a recurrent time-delay network. The extraction is executed by the matching mechanism of the adaptive resonance system, and the temporal information is processed and stored by the recurrent network. Simple simulations are examined to exemplify the property of extraction.

An analysis of political efficacy socialisation among threshold voters in the Republic of Ireland

The spread of democracy in the latter part of the twenty first century has been accompanied by an increasing focus on its perceived performance in established western democracies. Recent literature has expressed concern about a critical outlook among younger cohorts which threatens their political support and engagement. Political efficacy, referring to the feeling of political effectiveness, is considered to be a key indicator of the performance of democratic politics; as it refers to the empowerment of citizens, and relates to their willingness to engage in political matters. The aim of this thesis is to analyse the socialisation of political efficacy among those on the threshold of political adulthood; i.e., 'threshold voters'. The long-term significance of attitudes developed by time of entry to adulthood for political engagement during adulthood has been emphasised in recent literature. By capturing the effect of non-political and political learning among threshold voters, the study advances existing research frames which focus on childhood and early adolescent socialisation. The theoretical and methodological framework applied herein recognises the distinction between internal and external political efficacy, which has not been consistently operationalized in existing research on efficacy socialisation. This research involves a case study of 'threshold voters' in the Republic of Ireland, and employs a quantitative methodology. A study on Irish threshold voters is timely as the parliament and government have recently proposed a lowering of the voting age and an expansion of formal political education to this age group. A project-specific survey instrument was developed and administered to a systematic stratified sample of 1,042 post-primary students in the Cork area. Interpretation of the results of statistical analysis leads to findings on the divergent influence of family, school, associational, and political agents/environments on threshold voter internal and external political efficacy.

Eficiencia de la capacitancia y altura de canopeo comprimido (con disco) para estimar biomasa forrajera

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Atomistic studies of interactions between the dominant lattice dislocations and γ/γ-lamellar boundaries in lamellar γ-TiAl

This paper reports on atomistic simulations of the interactions between the dominant lattice dislocations in ?-TiAl (<1 0 1] superdislocations) with all three kinds of ?/?-lamellar boundaries in polysynthetically twinned (PST) TiAl. The purpose of this study is to clarify the early stage of lamellar boundary controlled plastic deformation in PST TiAl. The interatomic interactions in our simulations are described by a bond order potential for L10-TiAl which provides a proper quantum mechanical description of the bonding. We are interested in the dislocation core geometries that the lattice produces in proximity to lamellar boundaries and the way in which these cores are affected by the elastic and atomistic effects of dislocation-lamellar boundary interaction. We study the way in which the interfaces affect the activation of ordinary dislocation and superdislocation slip inside the ?-lamellae and transfer of plastic deformation across lamellar boundaries. We find three new phenomena in the atomic-scale plasticity of PST TiAl, particularly due to elastic and atomic mismatch associated with the 60° and 120° ?/?-interfaces: (i) two new roles of the ?/?-interfaces, i.e. decomposition of superdislocations within 120° and 60° interfaces and subsequent detachment of a single ordinary dislocation and (ii) blocking of ordinary dislocations by 60° and 120° interfaces resulting in the emission of a twinning dislocation.

Lethal and sublethal toxicity of ammonia to native, invasive, and parasitised freshwater amphipods

In lethal and sublethal ammonia toxicity tests, we examined differences in tolerance of three species of freshwater amphipods, one native and two invasive in Ireland. The native Gammarus duebeni celticus was slightly less tolerant to ammonia than the invasive G. pulex (96h LC50 = 1.155 and 1.544 mg l(-1), respectively), while another invader, Crangonyx pseudograeilis, had the lowest tolerance (LC50 = 0.36 mg l(-1)). Parasitism of G. pulex by the acanthocephalan Echinorhynchus truttae greatly reduced the tolerance of the invader to ammonia (LC50 = 0.381 mg l(-1)). Further, precopula pair disruption tests indicated that G. d. celticus was more sensitive to ammonia than G. pulex at sublethal levels. We discuss these results in the context of the ecological replacements of native by invader amphipods. (C) 2004 Elsevier Ltd. All rights reserved.

Freeze-dried, mucoadhesive system for vaginal delivery of the HIV microbicide, dapivirine: Optimisation by an artificial neural network

Dapivirine mucoadhesive gels and freeze-dried tablets were prepared using a 3 x 3 x 2 factorial design. An artificial neural network (ANN) with multi-layer perception was used to investigate the effect of hydroxypropyl-methylcellulose (HPMC): polyvinylpyrrolidone (PVP) ratio (XI), mucoadhesive concentration (X2) and delivery system (gel or freeze-dried mucoadhesive tablet, X3) on response variables; cumulative release of dapivirine at 24 h (Q(24)), mucoadhesive force (F-max) and zero-rate viscosity. Optimisation was performed by minimising the error between the experimental and predicted values of responses by ANN. The method was validated using check point analysis by preparing six formulations of gels and their corresponding freeze-dried tablets randomly selected from within the design space of contour plots. Experimental and predicted values of response variables were not significantly different (p > 0.05, two-sided paired t-test). For gels, Q(24) values were higher than their corresponding freeze-dried tablets. F-max values for freeze-dried tablets were significantly different (2-4 times greater, p > 0.05, two-sided paired t-test) compared to equivalent gets. Freeze-dried tablets having lower values for X1 and higher values for X2 components offered the best compromise between effective dapivirine release, mucoadhesion and viscosity such that increased vaginal residence time was likely to be achieved. (C) 2009 Elsevier B.V. All rights reserved.

Dissonances in self-reported health and mortality across denominational groups in Northern Ireland

Measures of self-reported health status are increasingly used in research and health policy. However, the inherent subjectivity of the responses gives rise to lingering concerns about their utility, especially across national and cultural boundaries. In this study we use religious denomination as a proxy for Scottish ancestry within Northern Ireland and demonstrate significant differences in levels of self-reported ill-health that are not fully reflected in mortality risks. These findings mirror the differences between Scotland and Northern Ireland previously shown in ecological studies and provide more definitive evidence that even within the United Kingdom factors other than morbidity levels influence the perception and reporting of health status. Possible explanations for the dissonance between morbidity and mortality levels are discussed and the reasons for a preference for socio-economic rather than cultural factors are described. (C) 2010 Elsevier Ltd. All rights reserved.

Surface modification of poly(ε-caprolactone) using a dielectric barrier discharge in atmospheric pressure glow discharge mode

The role of roughening and functionalization processes involved in modifying the wettability of poly(e-caprolactone) (PCL) after treatment by an atmospheric pressure glow discharge plasma is discussed. The change in the ratio of Cdouble bond; length as m-dashO/C–O bonds is a significant factor influencing the wettability of PCL. As the contact angle decreases, the level of Cdouble bond; length as m-dashO bonds tends to rise. Surface roughness alterations are the driving force for lasting increases in wettability, while the surface functional species are shorter lived. We can approximate from ageing that the increase in wettability for PCL after plasma treatment is 55–60% due to roughening and 40–45% due to surface functionalization for the plasma device investigated.

The Economic Costs of Health Service Treatments for Asbestos-Related Mesothelioma Deaths

This article explores the complex and neglected picture of occupational and environmental disease healthcare costs specifically relating to asbestos. Diagnosed mesothelioma cases in Scotland in one calendar year were used to investigate the subject in greater depth. Data from UK sources on asbestos disease types recorded in 2000 and their disease treatment costs were obtained. Acute care economic costs of these diseases are estimated. One hundred and twenty diagnosed, recorded, and treated cases of asbestos-related diseases occurred in 2000 in Scotland. Mesothelioma accounted for 100 cases and directly cost Scottish National Health Service hospitals an estimated 942,038 pounds. The estimated UK figure in 2000 was at least 16,014,646 pounds because official figures for diagnosed and recorded deaths from mesothelioma are running at over 1700 a year with rises predicted for 2010 of 2000 deaths. By 2003, 50,000 people in the UK had died from diagnosed and recorded mesothelioma since records began. Earlier disease treatment costs would have been significantly lower than those in 2000 but, at 2000 prices, cost to the UK was roughly 471,019,000 pounds in acute hospital expenditure. Figures for primary care costs, including caregiver costs, are incomplete or unknown. These disease costs are substantial and have some international generalizability. Treatment patterns and costs vary greatly. Many lung cancer cases due to asbestos exposure occur globally for each mesothelioma case. Hence figures provided in this article are certain to be gross underestimates of the total health service and personal economic costs of asbestos illness and treatment in Scotland.