Towards a generic OLED lifetime model

Abstract— The limitations of t^1/2 lifetime testing for OLED displays are discussed in the context of permanent and recoverable luminance decay. Different pixel drive schemes, operating temperature, and schemes of gray‐level generation are all found to be important in determining the operational lifetime where both permanent and recoverable contributions to the luminance decay exist. In addition, the importance of assessing lifetime with respect to a particular usage model is introduced and a method of lifetime characterization is devised to account for all of the factors discussed. The method measures luminance degradation over a series of operating cycles where the stress factors on the display are randomly generated for each cycle. The luminance degradation is then analyzed with linear regression, and the regression fit coefficients give an understanding of the degradation in different usage models so that an assessment of the display's suitability for a particular application can be made.     

A Novel Organic “Polyurea” Thin Film for Ultralong‐Life Lithium‐Metal Anodes via Molecular‐Layer Deposition

Metallic Li is considered as one of the most promising anode materials for next‐generation batteries due to its high theoretical capacity and low electrochemical potential. However, its commercialization has been impeded by the severe safety issues associated with Li‐dendrite growth. Non‐uniform Li‐ion flux on the Li‐metal surface and the formation of unstable solid electrolyte interphase (SEI) during the Li plating/stripping process lead to the growth of dendritic and mossy Li structures that deteriorate the cycling performance and can cause short‐circuits. Herein, an ultrathin polymer film of “polyurea” as an artificial SEI layer for Li‐metal anodes via molecular‐layer deposition (MLD) is reported. Abundant polar groups in polyurea can redistribute the Li‐ion flux and lead to a uniform plating/stripping process. As a result, the dendritic Li growth during cycling is efficiently suppressed and the life span is significantly prolonged (three times longer than bare Li at a current density of 3 mA cm^?2). Moreover, the detailed surface and interfacial chemistry of Li metal are studied comprehensively. This work provides deep insights into the design of artificial SEI coatings for Li metal and progress toward realizing next‐generation Li‐metal batteries.     

Bridge strike reduction: optimising the design of markings

Cases of high-sided vehicles striking low bridges is a large problem in many countries, especially the UK. This paper describes an experiment to evaluate a new design of markings for low bridges. A full size bridge was constructed which was capable of having its overhead clearance adjusted. Subjects sat in a truck cab as it drove towards the bridge and were asked to judge whether the vehicle could pass safely under the bridge. The main objective of the research was to determine whether marking the bridge with a newly devised experimental marking would result in more cautious decisions from subjects regarding whether or not the experimental bridge structure could be passed under safely compared with the currently used UK bridge marking standard. The results show that the type of bridge marking influenced the level of caution associated with decisions regarding bridge navigation, with the new marking design producing the most cautious decisions for the two different bridge heights used, at all distances away from the bridge structure. Additionally, the distance before the bridge at which decisions were given had an effect on the level of caution associated with decisions regarding bridge navigation (the closer to the bridge, the more cautious the decisions became, irrespective of the marking design). The implications of these results for reducing the number of bridge strikes are discussed.     

Comparison of clay mineral stratigraphy to other proxy palaeoclimate indicators in the Mesozoic of NW Europe

This paper reviews the opportunities and pitfalls associated with using clay mineralogical analysis in palaeoclimatic reconstructions. Following this, conjunctive methods of improving the reliability of clay mineralogical analysis are reviewed. The Mesozoic succession of NW Europe is employed as a case study. This demonstrates the relationship between clay mineralogy and palaeoclimate. Proxy analyses may be integrated with clay mineralogical analysis to provide an assessment of aridity-humidity contrasts in the hinterland climate. As an example, the abundance of kaolinite through the Mesozoic shows that, while interpretations may be difficult, the Mesozoic climate of NW Europe was subject to great changes in rates of continental precipitation. We may compare sedimentological (facies, mineralogy, geochemistry) indicators of palaeoprecipitation with palaeotemperature estimates. The integration of clay mineralogical analyses with other sedimentological proxy indicators of palaeoclimate allows differentiation of palaeoclimatic effects from those of sea-level and tectonic change. We may also observe how widespread palaeoclimate changes were; whether they were diachronous or synchronous; how climate, sea level and tectonics interact to control sedimentary facies and what palaeoclimate indicators are reliable.     

A hybrid system for embedded machine vision using FPGAs and neural networks

This paper presents a hybrid model for embedded machine vision combining programmable hardware for the image processing tasks and a digital hardware implementation of an artificial neural network for the pattern recognition and classification tasks. A number of possible architectural implementations are compared. A prototype development system of the hybrid model has been created, and hardware details and software tools are discussed. The applicability of the hybrid design is demonstrated with the development of a vision application: real-time detection and recognition of road signs.     

Type inference and strong static type checking for Promela

The Spin model checker and its specification language Promela have been used extensively in industry and academia to check the logical properties of distributed algorithms and protocols. Model checking with Spin involves reasoning about a system via an abstract Promela specification, thus the technique depends critically on the soundness of this specification. Promela includes a rich set of data types including first-class channels, but the language syntax restricts the declaration of channel types so that it is not generally possible to deduce the complete type of a channel directly from its declaration. We present the design and implementation of Etch, an enhanced type checker for Promela, which uses constraint-based type inference to perform strong type checking of Promela specifications, allowing static detection of errors that Spin would not detect until simulation/verification time, or that Spin may miss completely. We discuss theoretical and practical problems associated with designing a type system and type checker for an existing language, and formalise our approach using a Promela-like calculus. To handle subtyping between base types, we present an extension to a standard unification algorithm to solve a system of equality and subtyping constraints, based on bounded substitutions.     

High-Throughput Screening for High Affinity Antibodies

The UCB SLAM process described here has had a positive and dramatic effect on the way we select therapeutic candidate antibodies. An example of the number of cells that can be screened using UCB SLAM is shown in Table 2. UCB previously used the hybridoma method to generate antibodies for both research and for therapy.^{[5] and [6]} This method, we believed, was not particularly amenable to automation, due to the large amount of cell culture involved in both setting up the fusion and then maintaining the hybridoma cell lines, although this approach has been adopted by others.⁷ The in vitro culture of B cells, combined with the process automation has allowed many more antibodies to be screened, with hybridoma only those B cells that have fused with the myeloma are available for screening, this is only a small proportion of the total number of B cells. UCB SLAM B cell cultures can be screened a week after they are set up compared with 2–3 weeks for hybridoma. Advances in the molecular biology have allowed us to move away from the time-consuming dilution cloning of cells to select antibodies; the antibody genes can be isolated, sequenced, and recombinant antibody transiently expressed in 2 weeks. The method does not require a species specific, myeloma cell line as a fusion partner, which means there is no constraint on B cell source species. The lack of a B cell fusion event means that a highly efficient sampling of the B cell repertoire can be achieved. We have found the process to be applicable to generating research reagents, high quality antibodies to animal target antigens.⁸ These research reagents can be raised to different target antigen epitopes than used in both in vitro and in vivo mechanistic and disease models. The research reagents are a significant aid to investigate the complex biology of our targets. The lack of species-specific fusion partners makes this approach a challenge for hybridoma, particularly when there is a need to generate antibodies to mouse and rat antigens.     

Metamodel-based collaborative optimization framework

This paper focuses on the metamodel-based collaborative optimization (CO). The objective is to improve the computational efficiency of CO in order to handle multidisciplinary design optimization problems utilising high fidelity models. To address these issues, two levels of metamodel building techniques are proposed: metamodels in the disciplinary optimization are based on multi-fidelity modelling (the interaction of low and high fidelity models) and for the system level optimization a combination of a global metamodel based on the moving least squares method and trust region strategy is introduced. The proposed method is demonstrated on a continuous fiber-reinforced composite beam test problem. Results show that methods introduced in this paper provide an effective way of improving computational efficiency of CO based on high fidelity simulation models.     

The Deutsch–Jozsa problem: de-quantisation and entanglement

The Deutsch–Jozsa problem is one of the most basic ways to demonstrate the power of quantum computation. Consider a Boolean function f : {0, 1} ⁿ → {0, 1} and suppose we have a black-box to compute f. The Deutsch–Jozsa problem is to determine if f is constant (i.e. f(x) = const, "x ? {0,1}ⁿf(x) = \hbox {const, } \forall x \in \{0,1\}^n) or if f is balanced (i.e. f(x) = 0 for exactly half the possible input strings x ? {0,1}ⁿx \in \{0,1\}^n) using as few calls to the black-box computing f as is possible, assuming f is guaranteed to be constant or balanced. Classically it appears that this requires at least 2 ⁿ⁻¹ + 1 black-box calls in the worst case, but the well known quantum solution solves the problem with probability one in exactly one black-box call. It has been found that in some cases the algorithm can be de-quantised into an equivalent classical, deterministic solution. We explore the ability to extend this de-quantisation to further cases, and examine with more detail when de-quantisation is possible, both with respect to the Deutsch–Jozsa problem, as well as in more general cases.     

Site-specific attachment to recombinant antibodies via introduced surface cysteine residues

Many diagnostic and therapeutic applications of monoclonal antibodiesrequire the covalent linking of effector or reporter moleculesto the immunoglobulin polypeptides. Existing methods generallyinvolve the non-selective modification of amino acid side chains,producing one or more randomly distributed attachment sites.This results in heterogeneous labelling of the antibody moleculesand often to a decrease in antigen-binding due to the modificationof residues close to the antigen-binding site. We report a novelstrategy for site-specifically labelling antibodies throughsurface cysteine residues. Examination of molecular structureswas used to identify amino acids of the C_H1 domain of the IgGheavy chain that were accessible to solvent but not to largermolecules. Site-directed mutagenesis was used to substitutecysteine residues at these positions in the heavy chain of amouse/human chimaeric version of the tumour-binding monoclonalantibody, B72.3. Expression of the modified antibody genes inmammalian cells yielded correctly assembled proteins that hadthiol groups in pre-determined positions and showed no lossof antigen-binding activity. One of the mutants was used todemonstrate the site-specific attachment of a radio-iodinatedligand to the chimaeric B72.3 antibody.