Combination of Cobalt and Iron Polypyridine Complexes for Improving the Charge Separation and Collection in Ru(terpyridine)2‐Sensitised Solar Cells

Mixtures of polypyridine Fe^II and Co^II complexes are used as electron mediators in Ru–thienyltpy‐sensitised solar cells (tpy=terpyridine). The use of the metalorganic redox couples allows for improved charge‐collection efficiency with respect to the classical iodide/iodine couple which, when associated to Ru–tpy₂ dyes, usually produces poor performance. The improved charge collection is explained by a combination of effective dye regeneration and decreased recombination with the oxidised electrolyte on the basis of data obtained by transient spectroscopy and photoelectrochemical measurements. The efficiency of the regeneration cascade is also critically dependent upon the ability of the Co^II complex to intercept Fe^III centres, as clearly indicated by chronocoulometry experiments.     

Gas collection efficiency of annular denuders: A spreadsheet-based calculator

Denuders are widely used for atmospheric analysis. Annular denuders are especially well-suited for preconcentration of trace gases compared to simpler single tube designs. While traditionally coated annular denuders have both bounding surfaces that behave as sinks, annular denuders/membrane-based scrubbers with the same basic geometric design and with only one of the annular surfaces functioning as sink (e.g., a membrane tube whose outer surface behaves as a sink disposed within an inert jacket tube) have become common. However, the gas collection efficiency of such devices cannot be expressed as a simple equation with fixed constants and there is no presently available tool to a priori determine the denuder performance or to design denuders with specific removal efficiencies at specific sampling rates. This paper presents a simple to use “spreadsheet calculator” for concentric annular denuders of any dimension based on known solutions to analogous heat transfer problems. The results from the present spreadsheet calculator are compared with results from a commercial computational fluid dynamics package (Fluent™; this takes significant expertise and development effort to run)—the two approaches produce essentially the same results. The present spreadsheet calculator can be used easily and simply without training and will be a useful tool for denuder users and designers.     

A novel class of graded cylinders neutral to host shafts of arbitrary cross-sections under torsion

A novel class of graded cylinders is proposed as neutral inclusions inside host shafts of arbitrary cross-section under Saint-Venant's torsion. The graded cylinder is made of cylindrically orthotropic materials with position varying quantities. The profiles of the two distinct shear moduli in the radial and tangential directions follow specific forms based on an arbitrarily selected function along the radial distance. We show that this type of graded cylinders can serve as universal neutral inclusions within host shafts of arbitrary cross-sections. In addition, we find that the associated warping fields can be exactly determined in terms of simple exponents of the selected function. This suggests that, by tuning the gradation parameter, one can manipulate the warping field of the inserted cylinder without disturbing the fields inside the host shaft. This finding is an original contribution to the existing solvable configurations of composite shafts under torsion.     

普朗克常量测定系统中实验数据的采集和处理

介绍了在光电效应实验系统改造中，关于实验数据的采集和处理方法。     

改进的TOPSIS决策方法在供应商选择中的应用

运用马氏距离替代欧式距离改进传统的TOPSIS方法,解决当属性间存在线性相关时欧式距离失效的缺陷;充分考虑对立集合并引入联系向量距离,解决可能存在的方案距离正理想解和负理想解距离都近的缺陷.然后通过决策者偏好系数将马氏距离和联系向量距离所得结果合成新的相对贴近度,从而同时克服传统TOPSIS方法的以上两个缺陷.最后通过供应商选择的实例来验证方法的有效性.     

$G$-交叉积在$G$-inner作用下的等价刻画

本文给出两个具有相同半格$Y$ 的半格分次弱Hopf代数的$G$-inner 作用的定义, 然后给出两个$G$-交叉积同构的充分必要条件.     

一类广义Heisenberg-Virasoro代数的导子

主要研究了一类非有限分次的广义Heisenberg-Virasoro代数HV,并给出了HV导子的具体结构.为了计算HV的导子Der HV,可以把它分解成内导子adHV和阶为零次的导子(Der HV)_0之和.     

From Lie algebra crossed modules to tensor hierarchies

The present paper, though inspired by the use of tensor hierarchies in theoretical physics, establishes their mathematical credentials, especially as genetically related to Lie algebra crossed modules. Gauging procedures in supergravity rely on a pairing – the embedding tensor – between a Leibniz algebra and a Lie algebra. Two such algebras, together with their embedding tensor, form a triple called a Lie-Leibniz triple, of which Lie algebra crossed modules are particular cases. This paper is devoted to showing that any Lie-Leibniz triple induces a differential graded Lie algebra – its associated tensor hierarchy – whose restriction to the category of Lie algebra crossed modules is the canonical assignment associating to any Lie algebra crossed module its corresponding unique 2-term differential graded Lie algebra. This shows that Lie-Leibniz triples form natural generalizations of Lie algebra crossed modules and that their associated tensor hierarchies can be considered as some kind of ‘lie-ization’ of the former. We deem the present construction of such tensor hierarchies clearer and more straightforward than previous derivations. We stress that such a construction suggests the existence of further well-defined Leibniz gauge theories.     

Improving Data Quality in Traditional Low-Dose Scanning Transmission Electron Microscopy Imaging

It has become very important to study and find optimal conditions for imaging electron-beam (e-beam) sensitive materials in scanning transmission electron microscopy under low electron-dose with high signal-to-noise ratio (SNR). Convergence and collection angles and electron-probe current are essential parameters. However, these parameters have rarely been discussed in a systematic way. In this paper, the illumination and collection conditions are optimized according to the resolution requirement of different materials by adjusting the condenser and intermediate lenses in a commercial transmission electron microscope. To demonstrate the significance of optimizing these parameters, two examples, zeolite MFI and metal–organic framework (MOF) MIL-101, are taken among the sensitive materials, with the most important electron incidences along the [010] and <110> directions, respectively. High SNR atomic resolution images of MFI are obtained with e-beam current as low as 0.50 pA, reaching information transfer for reflection up to 18 0 2 corresponding to d-spacing of 0.11 nm, close to the resolution limit of 0.098 nm from resolvable diffraction limit. MOF MIL-101 is characterized under an even lower e-beam 0.2 pA to avoid severe beam damage. High-quality annular dark and bright field images are obtained, which proves the wide applicability of this method on more e-beam sensitive materials.     

极化诱导实现AlGaN薄膜材料中的超高电子浓度(1020cm-3)掺杂

材料的载流子浓度和迁移率是影响器件性能的关键因素, 变温Hall测试结果证明杂质掺杂AlGaN中的载流子浓度和迁移率随温度 降低而减小.然而极化诱导掺杂的载流子浓度和迁移率不受温度变化的影响.以准绝缘 的GaN体材料作为衬底, 在组分分层渐变的AlGaN中实现的极化诱导掺杂浓度 仅仅在10¹⁷ cm^-3数量级甚至更低. 本研究采用载流子浓度为10¹⁶ cm^-3量级的非有意n型掺杂GaN模板为衬底, 用极化诱导掺杂技术在分子束外延生长的AlGaN薄膜材料中实现了高 达10²⁰ cm^-3 量级的超高电子浓度. 准绝缘的体材GaN半导体作衬底时, 只有表面自由电子作为极化掺杂源, 而非有意掺杂的GaN模板衬底除了提供表面自由电子外,还能为极化电场 提供更多的自由电子"源", 从而实现超高载流子浓度的n型掺杂.