Metallhalogenid-Perowskite (MHPs) sind Halbleiter, die einzigartige photophysikalische Eigenschaften aufweisen, die sie ideal für photovoltaische Anwendungen machen. Techniken werden kontinuierlich entwickelt, um die Leistungsgrenzen der Perowskite weiter zu verschieben. Dennoch weisen diese Materialien verschiedene Herausforderungen auf. Zu diesen gehören eine geringe Stabilität unter einer Vielzahl von äußeren Bedingungen, sowie eine große Diskrepanz zwischen den Wirkungsgraden von Geräten im Labormaßstab und großflächigen Geräten. Zunächst wurden mit Hilfe von Photolumineszenz-Spektroskopie Ladungsübertragungsmechanismen zwischen MHPs und atmosphärischen Gasen untersucht, um deren Einfluss auf die Materialstabilität zu bestimmen. Durch den Vergleich der Emission von verschiedene MHP wurde die Wirkung untersucht, die atmosphärische Gase auf Grenzdefekte im Material haben. Diese Löschungseffekte wurden nachfolgend mit dem Stern-Volmer-Modell analysiert. Es stellte sich heraus, dass ein Teil von der Gase bindet jedoch an die MHPs, wobei teilweise Kristalldefekte passiviert werden und für jedes der Gase Ladungstransfermechanismen vorgeschlagen wurden. Zweitens wurde die Skalierung von MHP-Bauelementen mittels Tintenstrahldruck untersucht. Dazu wurden drei Kristallisationstechniken ausgewertet. Eine davon verwendete eine sequenzielle Abscheidung von zwei Präkursortinten, während die beiden anderen kristallisierte Tinten verwendeten, die in einem Schritt abgeschieden wurden. Die letztgenannten Techniken verwendeten beide niedrige Drücke und bei einer wurde ein kontrollierter Stickstoffstrom auf die Probe angewendet. Solarzellen mit einer Effizienz von 16,8% auf einer Fläche von 0,16 cm² wurden demonstriert. Diese Ergebnisse zeigen ein neuartiges Verfahren zur Untersuchung von strahlungslosen Verlustwegen in MHPs auf. Zusätzlich demonstrieren diese Studien, dass der Tintenstrahldruck eine geeignete Technologie ist, um MHP-Bauelemente zu skalieren. / Metal halide perovskites (MHPs) are semiconductor materials that show unique photophysical properties, making them ideal for photovoltaic applications. Having shown power conversion efficiencies of up to 25.5%, techniques are continuously being developed to push perovskites to unprecedent limits. Yet, these materials present challenges like a low stability under a variety of conditions as well as a large disparity between the efficiencies of lab scale and large area devices. This thesis addresses these two major obstacles. First, charge transfer mechanisms between MHPs and atmospheric gases were studied to determine their effect on the material stability by using photoluminescence spectroscopy. By comparing the emission of MHPs, the effect that molecular oxygen, nitrogen, argon, and water have on boundary defects in the material was studied. These quenching effects were later analyzed using the Stern-Volmer model. It was found that the gases bounce off the surface, but a portion of them bind to the MHPs, in occasions passivating defects on the crystals. Using these results, charge transfer mechanisms were proposed for each one of the gases. Second, scaling of MHP devices was examined using inkjet printing. For this, three crystallization techniques were evaluated. One of them used sequential deposition of two precursor inks, while the other two crystallized ink that was deposited in one step. Both latter techniques used low pressures, below 1 mbar, and only one of them applied a controlled stream of nitrogen to the sample. Using these techniques, the deposition of a 15x15 cm² area as well as a device with an efficiency of 16.8% on an area of 0.16 cm² were demonstrated. These results show a novel procedure to study non-radiative loss paths in MHPs to enhance their stability and performance as devices. Also, they show that inkjet printing is a favorable technology to scale MHP devices and eventually facilitate the mass production of this type of photovoltaic devices.

No description available.

In this thesis I examine women's participation in the violent revolutionary organization, Weatherman/Weather Underground. My attempt is to uncover Weatherman's view of women's liberation, their differences to the women's liberation movement and examine the practices implemented. I discuss Weatherman, more generally, in the context and circumstances of their emergence from the Students for a Democratic Society in the late sixties. Influenced by popular revolutionary thinkers Weatherman declared itself and its members revolutionaries dedicated to bringing about a socialist revolution in the United States through strategies of guerilla warfare. Weatherman's insistence on revolutionary violence situated masculinity and machismo within the center of their politics and practice. Weatherman promised its female members liberation through violence and machismo in the fight for a socialist revolution. I explore Weatherman's political position on women's liberation and the result of their politics evident in autonomous women's actions and sexual practices. In addition, I contend that Weatherman's politics more generally, and women's participation in Weatherman was shaped by the cultural hegemony of masculinity, termed by Connell as hegemonic masculinity. Exploration of women's participation in political violence is important to the acknowledgment of women as agents of aggression and the gender fluidity they represent. Weatherwomen's acceptance and adoption of masculinity provides an example of gender fluidity in contexts outside of common homosexual, transgendered, or queer representations. Furthermore, varying perceptions of women's liberation during the late sixties and early seventies has yet to be explored outside of the narrow scope of the autonomous feminist movement. Women who participated in the Weatherman/Weather Underground, their politics of women's liberation and methods in which to accomplish liberation have been ignored by historians of feminism and the New Left. This thesis uncovers the politics of women's liberation in the Weatherman/ Weather Underground, through which I examine the meaning of women's liberation, methods of liberation, and the empowered and limited position of women within the Weatherman/Weather Underground.

We analyze a coincidence Stern-Gerlach measurement often discussed in connection with the derivation and illustration of Bell's theorem. The treatment is based on our recent analysis of the original Stern-Gerlach experiment (PCCP, 14, 1677‐1684 (2012)), where it is concluded that it is necessary to include a spin relaxation process to account for the experimental observations. We consider two limiting cases of a coincidence measurement using both an analytical and a numerical description. In on limit relaxation effects are neglected. In this case the correlation between the two spins present in the initial state is conserved during the passage through the magnets. However, at exit the z coordinate along the magnetic field gradient is randomly distributed between the two extreme values. In the other limit T2 relaxation is assumed to be fast relative to the time of flight through the magnet. In this case the z coordinate takes one of two possible values as observed in the original Stern‐Gerlach experiment. Due to the presence of a relaxation process involving transfer of angular momentum between particle and magnet the initially entangled spin state changes character leading to a loss of correlation between the two spins. In the original derivations of Bell's theorem based on a coincidence Stern‐Gerlach setup one assumes both a perfect correlation between the spins and only two possible values for the z‐coordinate on exit. According to the present calculations one can satisfy either of these conditions but not both simultaneously.

A new technique is developed that uses planar laser-induced fluorescence (PLIF) imaging of sublimated naphthalene to image the transport of ablation products in a hypersonic boundary layer. The primary motivation for this work is to understand scalar transport in hypersonic boundary layers and to develop a database for validation of computational models. The naphthalene is molded into a rectangular insert that is mounted flush with the floor of a Mach 5 wind tunnel. The distribution of naphthalene in the boundary layer is imaged by using PLIF, where the laser excitation is at 266 nm and the fluorescence is collected in the range of 320 to 380 nm. To investigate the use of naphthalene PLIF as a quantitative diagnostic technique, a series of experiments is conducted to determine the linearity of the fluorescence signal with laser fluence, as well as the temperature and pressure dependencies of the signal. The naphthalene fluorescence at 297 K is determined to be linear for laser fluence that is less than about 200 J/m². The temperature dependence of the naphthalene fluorescence signal is found at atmospheric pressure over the temperature range of 297K to 525K. A monotonic increase in the fluorescence is observed with increasing temperature. Naphthalene fluorescence lifetime measurements were also made in pure-air and nitrogen environments at 300 K over the range 1 kPa to 40 kPa. The results in air show the expected Stern-Volmer behavior with decreasing lifetimes at increasing pressure, whereas nitrogen exhibits the opposite trend. Preliminary PLIF images of the sublimated naphthalene are acquired in a Mach 5 turbulent boundary layer. Relatively low signal-to-noise-ratio images were obtained at a stagnation temperature of 345 K, but much higher quality images were obtained at a stagnation temperature of 380 K. The initial results indicate that PLIF of sublimating naphthalene may be an effective tool for studying scalar transport in hypersonic flows. / text

The eighteenth-century British novel derived its purpose, structure, and theory of characterization from the life-history, in the form of biography or autobiography. In eighteenth-century Britain both the novel and the life-history emerged in recognizably modern forms. Like the life-history, the novel maintained as its purpose the Horatian maxim that art should both instruct and entertain. Moreover, the novel and the life-history shared the same structure, as each novel purported to be the biography or autobiography of the title character of the work. Finally, the novel and the life-history adopted the same theories of characterization for the major as well as minor characters within the works.However, life-writing was at this time in a period of transition from the static to the dynamic theory of characterization. This transition came as a result of a significant change in the view of the source of personality. In the static life-history the central subject, as well as the minor figures, possessed an innate, unchanging personality. Thus when Plutarch wrote of Alexander or of Julius Caesar, these figures were depicted as men born to greatness. However, each was imperfect, possessing in the Aristotelian sense a tragic flaw. In the main this theory was significant because it placed no value on what was later to be considered so important in the development of personality-the individual's experiential life.In direct contrast to the static theory, the dynamic view of personality was the result of Cartesian and Lockean psychology which saw personality as the direct result of not the innate but instead the experiential processes. The experiences of the central character, rather than exemplifying innate qualities, now were seen as shaping and delineating that personality. The application of this new theory to both the modern novel and life-history produced a central character or characters growing according to the dynamic theory, though the minor characters remained "type" characters in accordance with the static theory.Therefore, the sources of the British eighteenth-century novel lay both in the dynamic biographies and autobiographies of the Restoration and Eighteenth Century and in the classical life-writers beginning with Plutarch and Josephus, as well. In this study the primary classical works analyzed are Josephus, the portrait of Herod in the Jewish Antiquities and his own in The Life; Plutarch's "Julius Caesar" and Suetonius' "Julius Caesar"; St. Augustine's Confessions; Dante's Vita Nuova; and the transitional Autobiography of Benvenuto Cellini. The adoption of the new dynamic theory is illustrated in two life-histories: Colley Cibber's Apology and Samuel Johnson's Life of Savage.The application of the dynamic theory to eighteenth-century autobiographical novels is exemplified by Samuel Richardson's Pamela and Tobias G. Smollett's Roderick Random. Though there was a complex psychological portrait of Richardson's Pamela Andrews, with a number of moral digressions, there were little character development and few digressions in Smollett's novel.A far more complex treatment of the theories of personality occurred in Laurence Sterne's Tristram Shandy. As narrator Tristram centered the work upon the four.crucial accidents that had formed his personality, and on those other three dynamic characters who were connected with these misfortunes--the Shandy brothers and Parson Yorick. In contrast, minor characters such as Dr. Slop were drawn according to the static theory. The digressions within the work were encased within a comic-satiric framework. Thus the two theories of personality--static and dynamic--which informed eighteenth-century life-writing served also as the principal source for characterization in the eighteenth-century British autobiographical novel.

I detta examensarbete ville vi undersöka vad barnen som till synes inte leker med andra barn gör och hur några förskollärare talar om dessa barn.I undersökningen har fokus legat på samspelet mellan barn-barn vilket undersökts genom observationer. De vuxnas tankar och syn på hur de kan/bör förhålla sig till dessa barn har framställts genom intervjuer. Vi har gjort observationer och vuxenintervjuer på en förskola belägen i centrala Stockholm. Förskolan har vi valt att namnge till Skogsmullen och avdelningarna namngav vi till Ugglan och Björnen. För att få ännu en infallsvinkel har vi intervjuat en utbildare inom synsättet Vägledande samspel, som bland annat bottnar i psykoanalytikern Daniel Sterns begrepp. Det empiriska materialet har vi valt att koppla och analysera i relation med Sterns teorier och begrepp. Resultatet i vår studie visar att barnen är aktiva i sitt görande, genom bland annat iakttagande och ensamlek. Under intervjuerna framkom två olika saker, det första var att barn kan välja att iaktta lek och det andra var att de kan behöva ett stöd för att våga ge sig in i leken. / In this thesis work, we wanted to look into what the children do that don’t seem to play with other children.We also wanted to investigate how the preschool teachers talk about these children. In this survey focus has been on the interaction between children which has been examined through observations.The thoughts of the adults and their view of how they coould/should relate to children that don´t seem to take part in the play has been brought forward through interviews. We have made observations and interviews in a preschool in central Stockholm. We have named the preschool ”Skogmullen” and the department ”Ugglan” and ”Björnen”.To get yet another perspective, we have intervued an educator in “International Child Development Programme“ that is grounded in (profession) Daniel Stern's concept. We have choosen to connect and analyse the empiric material in relation to Stern's theories and concept.The results of our survey shows that the children are active in what they are doing when playing alone. During the interviews it was emphasised that children can choose to observe or they may need support to participate in the play.

Theoretical models for the electrokinetics of weakly permeable porous colloidal particles are absent from the literature. The understanding of this topic will be advanced through a systematic analysis of the standard electrokinetic equations, resulting in a theory for the electrophoretic mobility of weakly permeable porous colloidal particles. / The standard electrokinetic equations are employed to model the flux of solvent and ions outside the porous particle. To be consistent with this approach, the flux of solvent and ions in the pores must also be governed by the standard electrokinetic equations. However, in practice, only transport phenomena on the particle scale are observed and it is sufficient for information regarding pore-scale behaviour to be retained purely in the form of averaged quantities. To complete the theoretical description, the standard electrokinetic equations outside the particle must be coupled to particle-scale transport equations inside the particle via boundary conditions at the porous/free-fluid interface. / It has been shown experimentally and theoretically for coupled Stokes and Darcy flows, that the correct interfacial boundary condition for the tangential external flow is given by the Beavers-Joseph-Saffman (BJS) condition. The effect of the BJS boundary condition on the hydrodynamic drag on an oscillating porous particle is investigated. It is found that the particle may be regarded as impermeable with a slip length independent of frequency, and the resulting drag is significantly reduced in comparison with an equivalent impermeable particle that does not exhibit a slip length. / The transport of a general electrolyte solution through a rigid porous body subjected to a static (d.c.) electric field is studied. The pore-scale description is given by the standard electrokinetic equations, including the effects of ion diffusion, electromigration and convection. Homogenization theory is used to derive transport equations that capture the particle-scale behaviour. It is proven that the transport coefficient tensors obey Onsager’s reciprocal relations and the diagonal coefficient tensors are positive definite. / New interfacial boundary conditions are derived using conservation arguments supplemented by Stern-layer theory. When combined with the particle-scale transport equations, these boundary conditions incorporate four principal effects into the standard electrokinetic model: solvent slip and Stern-layer ionic conduction at the interface, and macroscopic ionic conduction together with the electroosmotic flow of solvent through the particle. / The method of matched asymptotic expansions is then used to construct an approximate solution to the aforementioned system, in the thin double-layer limit. An expression for the electrophoretic mobility of a weakly permeable colloidal sphere is produced that consists of a generalization of Smoluchowski’s formula to encompass porous particles, and a next order correction. For the first time, the effects of solvent slip and Stern-layer ionic conduction within the porous/free-fluid interface, in conjunction with macroscopic ionic conduction and electroosmosis through the particle, are exhibited. It is shown that solvent slip at the porous interface is overwhelmingly the dominant effect on the mobility of weakly permeable porous colloidal particles.

Thesis (Ph. D.)--Lehigh University, 1998. / Includes vita. Includes bibliographical references (leaves 256-271).

Universiẗat, Diss., 1999--München.