Electroluminescent devices based on blended polymeric thin films

This thesis is concerned with the characteristics of organic light-emitting devices based on the polymer poly(2֊methoxy֊5-(5'-ethyIhexyloxy)֊p֊phenylenevinylene) (MEH-PPV).The emissive layer of each device was formed either from pure MEH-PPV or from a blend of MEH-PPV with an electron-transporting small molecule material. A film of either indium tin oxide (ITO) or aluminium-doped zinc oxide (AZO) on glass was used to provide a transparent anode. The pure or blended emissive material was spin-coated from solution onto the anode. Calcium or aluminium cathodes were deposited by thermal evaporation onto the emissive film. The cutrent-voltage, light-voltage, quantum efficiency and stability characteristics of the devices were obtained using purpose-designed measurement equipment. These characteristics were influenced, amongst other factors, by the blend composition. The devices with an aluminium cathode and an emissive layer formed from 50 % MEH-PPV and 50 % PDPyDP had among the best characteristics. Compared with the equivalent unblended devices they averaged 40 times greater light emission, 35 times higher efficiency, and they emitted light for more than 18 days in place of tens of minutes. The half life of the most stable devices was 63 һ which, though much less than the tens of thousands of hours claimed by commercial developers, represents an increase of 30 times that of an unblended device. The increased light emission and quantum efficiency data resulted from the enhanced earner injection and transport provided by the electron transport material. It is suggested that the increased stability was caused by the small molecule material performing the role of a nano-encapsulation around each polymer chain. That is to say, the data suggest that each polymer chain was individually protected from the effects of contaminants such as oxygen and water vapour by the small molecule within the film .The choice of anode material also affected the rate of degradation. The surface morphology of the anode material of devices which had previously been operated for extended periods were analysed using an AFM. Electromigration of ITO anodes to form sharp spikes was not uncommon, particularly in devices with short lifetimes. As-deposited AΖO generally had a smoother morphology than as-deposited ITO. Following device operation fewer electromigtation spikes were observed in AZO than ITO

Results from the Rothamsted reference experiment II Yields of the crops and recoveries of N, P and K from manures and soil 1971-1975

C14

Diploma in Education? Rethinking the Curriculum.

For well over half a century the traditional end-on diploma year has been under fire from university departments, students, and the teaching profession. How is it possible in one year for students to reach adequate levels of knowledge and understanding in a large number of subjects, epistemologicalIy diverse and frequently outside their undergraduate experience? The answer of course, is that it is not possible to believe otherwise is to labour under gross delusion. A university department of education, acting with the best of intentions, cannot give more than cursory attention to even the most essential elements of a preservice programme within an abbreviated academic year

Structure of an anti-Aldol Addition Product of Benzaldehyde and a Pseudoephedrine-Derived O-Silyl Ketene N,O-Acetal

[4S-(4R*,5R*,8R*,9S*)]-2,2,5,6,8-Penta- methyl-4,9-diphenyl- 1,3-dioxa-6-aza-2-silacyclono-nan-7-one, CE2H29NO3Si, Mr = 383.56, monoclinic, P21, a = 6.550 (3), b = 17.318 (6), c = 20.129 (6) A, /3=98.83(3)° , V =2256.2(14) A 3, Z=4, Dx= 1.13 gcm -3, A(Mo Ka) = 0.71073 A,/z = 1.18 cm -1, F(000) = 824, room temperature, R on F = 0.039 for 4305 reflections with Fo 2 > 3cr(Fo2). The two independent molecules in this structure have nearly the same configuration and geometry. The Si atoms are tetrahedrally coordinated, with average Si--C bond distances of 1.842(3)/~ and average Si---O bond distances of 1.636 (7)A; angles at Si differ from 109.5 ° by an average of 3.5 °. The nine-membered rings are fully extended and the planes of the phenyl groups are approximately perpendicular to the nine- membered ring.Chemistry and Chemical Biolog

Inorganic synthesis-structure maps in zeolites with machine learning and crystallographic distances

Zeolites are inorganic materials known for their diversity of applications, synthesis conditions, and resulting polymorphs. Although their synthesis is controlled both by inorganic and organic synthesis conditions, computational studies of zeolite synthesis have focused mostly on organic template design. In this work, we use a strong distance metric between crystal structures and machine learning (ML) to create inorganic synthesis maps in zeolites. Starting with 253 known zeolites, we show how the continuous distances between frameworks reproduce inorganic synthesis conditions from the literature without using labels such as building units. An unsupervised learning analysis shows that neighboring zeolites according to our metric often share similar inorganic synthesis conditions, even in template-based routes. In combination with ML classifiers, we find synthesis-structure relationships for 14 common inorganic conditions in zeolites, namely Al, B, Be, Ca, Co, F, Ga, Ge, K, Mg, Na, P, Si, and Zn. By explaining the model predictions, we demonstrate how (dis)similarities towards known structures can be used as features for the synthesis space. Finally, we show how these methods can be used to predict inorganic synthesis conditions for unrealized frameworks in hypothetical databases and interpret the outcomes by extracting local structural patterns from zeolites. In combination with template design, this work can accelerate the exploration of the space of synthesis conditions for zeolites

TA treatment of depression : a hermeneutic single-case efficacy design study - ‘Anna’

This study is the first of a series of seven, and belongs to the second Italian systematic replication of findings from two previous series (Widdowson 2012a, 2012b, 2012c, 2013; Benelli, 2016a, 2016b, 2016c) that investigated the effectiveness of a manualised transactional analysis treatment for depression through Hermeneutic Single- Case Efficacy Design (HSCED). The therapist was a white Italian woman with 8 years of clinical experience and the client, Anna, was a 33-year old white Italian woman who attended 16 sessions of transactional analysis psychotherapy. Anna satisfied DSM-5 criteria for mild persistent depressive disorder (dysthymia) with anxious distress. The conclusion of the judges was that this was a good-outcome case: the dysthymic symptoms improved over the course of the therapy and were maintained in the ‘healthy’ range at the 6-month followup, the client reported a positive experience of the therapy and described important changes in intrapsychic and interpersonal patterns. In this case study, transactional analysis treatment for depression has proven its efficacy in treating persistent depressive disorder

TA treatment of depression : a hermeneutic single-case efficacy design study - ‘Caterina’

This study is the second of a series of seven, and belongs to the second Italian systematic replication of findings from two previous series (Widdowson 2012a, 2012b, 2012c, 2013; Benelli, 2016a, 2016b, 2016c) that investigated the effectiveness of a manualised transactional analysis treatment for depression through Hermeneutic Single-Case Efficacy Design. The therapist was a white Italian woman with 10 years of clinical experience and the client, Caterina, was a 28-year old white Italian woman who attended 16 sessions of transactional analysis psychotherapy. Caterina satisfied DSM-5 criteria for major depressive disorder with generalized anxiety disorder. The conclusion of the judges was that this was an outstanding good-outcome case: the depressive symptoms showed an early clinical and reliable improvement, maintained till the 6 months follow-up, accompanied by reductions in anxiety symptoms, global distress and severity of personal problems. Adherence to the manualised treatment for depression appears good to excellent. In this case study, transactional analysis treatment for depression has proven its efficacy in treating major depressive disorder in comorbidity with anxiety disorder

Efficient High-Order Space-Angle-Energy Polytopic Discontinuous Galerkin Finite Element Methods for Linear Boltzmann Transport

We introduce an $hp$-version discontinuous Galerkin finite element method (DGFEM) for the linear Boltzmann transport problem. A key feature of this new method is that, while offering arbitrary order convergence rates, it may be implemented in an almost identical form to standard multigroup discrete ordinates methods, meaning that solutions can be computed efficiently with high accuracy and in parallel within existing software. This method provides a unified discretisation of the space, angle, and energy domains of the underlying integro-differential equation and naturally incorporates both local mesh and local polynomial degree variation within each of these computational domains. Moreover, general polytopic elements can be handled by the method, enabling efficient discretisations of problems posed on complicated spatial geometries. We study the stability and $hp$-version a priori error analysis of the proposed method, by deriving suitable $hp$-approximation estimates together with a novel inf-sup bound. Numerical experiments highlighting the performance of the method for both polyenergetic and monoenergetic problems are presented.Comment: 27 pages, 2 figure

Overview of the JET ITER-like wall divertor

The work presented draws on new analysis of components removed following the second JET ITER-like wall campaign 2013–14 concentrating on the upper inner divertor, inner and outer divertor corners, life- time issues relating to tungsten coatings on JET carbon fibre composite divertor tiles and dust/particulate generation. The results show that the upper inner divertor remains the region of highest deposition in the JET-ILW. Variations in plasma configurations between the first and second campaign have altered ma- terial migration to the corners of the inner and outer divertor. Net deposition is shown to be beneficial in the sense that it reduces W coating erosion, covers small areas of exposed carbon surfaces and even encapsulates particles.EURATOM 633053RCUK Energy Programme EP/I50104