Ab initio study of Heusler alloys Co2XY (X = Cr,Mn, Fe; Y = Al,Ga) under high pressure

The structural, electronic, and magnetic properties of ferromagnetic Heusler alloys Co₂XY (X?=?Cr, Mn, Fe; Y?=?Al, Ga) have been investigated by means of the all-electron full-potential linearized augmented plane wave method within the generalized gradient approximation for the exchange and correlation potential. The main focus of this study is to elaborate the changes brought about in the electronic and the magnetic properties by applied pressure. The calculated total spin magnetic moments of all the compounds are found to be in good agreement with experiments. Out of these compounds, Co₂CrAl is found to be perfectly half-metallic (HM) and the other compounds are found to be nearly HM. Thus the HM to metal transition was observed at 75?GPa pressure for Co₂CrAl and the nearly half-metal to half-metal transition was observed at 40?GPa and 18?GPa for Co₂CrGa and Co₂MnAl, respectively, while no transition is observed in other compounds under investigation. It can be clearly seen that pressure affects the minority spin states rather than the majority states, leading to a slight reconstruction of the minority spin states with a shift in the Fermi level driving the above-mentioned transition.     

HRTEM observation of interfacial dislocations at faceted Al–Pb interfaces

Al–Pb ribbons containing 1?at.%?Pb have been produced by melt-spinning and subsequently investigated by high-resolution transmission electron microscopy. It is shown that the lattice mismatch of about 22% between the nanometre-sized Pb inclusions and the surrounding Al matrix is accommodated by a periodic array of misfit dislocations at the Al–Pb interface. The closing failures of Burgers circuits drawn around misfit dislocations on {111} and {100} facets identify the corresponding Burgers vectors as (a ₀/4)? 211 ? and (a ₀/2)? 110?, respectively. The Burgers vector of (a ₀/4)? 211? corresponds to the projected edge part of a 60° (a ₀/2)? 110? dislocation. The Pb inclusions themselves appear to be free of defects.     

Information on Information: Recent Curriculum Reform

Recent curriculum reform in western educational systems has seen a major emphasis on electronic technology, but reform literature seldom problematises the form that this new education should take in this new mode of information. From the particular case of New Zealand it is argued that knowledge has been replaced by information, knowing that (something is the case) by knowing how (acquiring skills), while electronic writing tends to be treated as a mere extension of print literacy. However, the information economy is a major force restructuring not only the curriculum but, also, our social and cultural relations, established notions of knowledge, authority, and rights, and our notions of subjectivity. The purpose of this paper is to problematise this move to information in the new electronic technologies.     

Electronic Monitoring of Medication Adherence: When Is High-Tech Best?

The accurate measurement of medication adherence is challenging, particularly in pediatrics. Electronic monitoring has been proposed as a possible gold standard for medication adherence measurement. Electronic monitoring permits the evaluation of patterns of medication use and dose-response relationship and may be a useful part of adherence promotion interventions. The use of these devices, however, is not without costs and cautions including, expense, malfunctioning, and interference with existing adherence routines. This review examines the costs and benefits of using electronic monitoring of adherence as well as the reliability and validity of electronic monitoring in general and, where possible, for specific devices (i.e., MEMS, MDIlog, and Doser). Finally, we provide recommendations for quality control protocols to minimize many of the problems encountered when using such devices. Ultimately, the choice of adherence measurement strategy should be based on the goal of the study and the resources available.     

移动支付对大学生冲动性消费行为的影响——来自ERP的实验证据

为寻找移动支付影响冲动性消费的电生理证据,实验采用两难选择的虚拟购物任务,通过2(支付方式)×2(产品类型)被试内实验设计,结合ERP技术比较移动支付和现金支付下的冲动消费及相关电生理指标。实验数据显示:(1)移动支付下参与者的购买意愿高于现金条件;(2)对享乐品的购买,移动支付下的购买意愿、购买率高于现金支付,而对实用品两种支付下无差异;(3)决策阶段头皮左侧发现,移动支付下享乐品的LPP波幅正于实用品,而现金支付下二者LPP波幅无差异;(4)N2波幅上存在Buy/No Buy效应。结果表明:移动支付促进了享乐品的冲动性消费,决策阶段左侧脑区的LPP波幅可作为其电生理指标,N2波幅表征买与不买。     

Potential fluctuations in phase change memory materials

Long-range potential fluctuations have been quantified in amorphous and crystallised thin films of a family of Ge–Sb–Te (GST) chalcogenide glasses. Among the compositions studied, the width of the potential fluctuations is the smallest for amorphous Ge₂Sb₂Te₅. This is also the most robust material in terms of the number of write–erase cycles for GST films when used as phase change memory materials. A plausible explanation for this observation is given and a criterion for selecting suitable compositions in optical memory devices is proposed.