Refine
Document Type
- Doctoral thesis (14)
- Conference proceeding (1)
Has Fulltext
- yes (15)
Is part of the Bibliography
- no (15)
Year of publication
- 2009 (15) (remove)
Language
- English (15) (remove)
Keywords
- Silicium (2)
- Umweltbezogenes Management (2)
- 60 GHz transceiver (1)
- 60-GHz-Transceiver (1)
- Akinet (1)
- Akinete (1)
- Andō (1)
- Anthropogener Einfluss (1)
- Architectural interpretation (1)
- Architektonische Interpretation (1)
Institute
- FG Experimentalphysik und funktionale Materialien (3)
- FG Systeme (2)
- FG ABWL, insbesondere Investition und Finanzierung (1)
- FG Architekturtheorie (1)
- FG Datenstrukturen und Softwarezuverlässigkeit (1)
- FG Energieverteilung und Hochspannungstechnik (1)
- FG Gewässerökologie (1)
- FG Mechanische Verfahrenstechnik (1)
- FG Sozialwissenschaftliche Umweltfragen (1)
- FG Ökologie (1)
Although phenomenology is primary a philosophical subject discussed by great philosophers such as Lambert, Herder, Kant, Fichte and Hegel, formulated by Husserl as a new way of doing philosophy, and later elaborated by features like Heidegger, Merleau-Ponty, Bachelard, and Gadamer in different ways, it has been used extensively by architectural theoreticians and architects in their investigations and designs. On the one hand, architectural theoreticians have taken phenomenological way of comprehending the world and environment as the departure point for establishing a unique understanding of architecture, city, and man-made environment, and propose a more proper method of analyzing. On the other hand, architects have tried to capture the essence of the things through a phenomenological contemplation, and incorporate their feelings into the architectural works. This dissertation intends to investigate the status of ‘phenomenology’ in the field of architectural theory and practice, study its advantages and disadvantages regarding analyzing and interpreting architectural buildings, propose a more comprehensive method of phenomenological interpretation, and examine it in the case of Langen Foundation Museum designed by Tadao Ando. This study is divided into three main parts of ‘question’, ‘inquiry’, and ‘towards an articulate phenomenological interpretation of architecture’. The first part deals with the question of phenomenology in both philosophy and architecture, and concentrates on the works of the philosophers Edmund Husserl, Martin Heidegger and Maurice Merleau-Ponty, and studies the architectural thoughts of Christian Norberg-Schulz, Juhani Pallasmaa, Kenneth Frampton, and Steven Holl, to introduce the main disadvantages of their phenomenological approach to architecture. The second part deals with the case study of Tadao Ando, and shows that the question of Ando in architecture is a two-fold one; the question of a relationship between theory and practice from one hand, and the question of interpretation and phenomenology on the other. To investigate this matter Ando’s architectural reflections will be introduced in the frame of main-narrative and sub-narratives. In the third part it will be shown that Ando’s reflections on architecture possess deep phenomenological concerns. Then, a new way of phenomenological interpretation – so called phenomenal phenomenology – will be drawn and applied in the case of the Langen Foundation Museum.
Nanotopography development induced by photoelectrochemical in situ conditioning of silicon is followed using a combination of surface sensitive analysis techniques. In an etching study, vertical nanostructure analysis reveals a buried stressed layer within silicon, identified by Brewster-angle analysis (BAA). In conjunction with in system synchrotron radiation photoelectron spectroscopy (SRPES), a superior quality hydrogen terminated Si(111) surface could be prepared by obliteration of the intermediate stressed layer. Using a novel photoelectrochemical structure formation method, a variety of vertical nanotopographies has been generated and analyzed by in situ Brewster-angle reflectometry (BAR) and scanning probe microscopy (SPM). Shaping of the nanostructures became possible by real-time monitoring using BAR. Appearances range from aligned single nanoislands with improved aspect ratio to connected Si nano-networks. A model was developed to describe the nanostructure formation based on stress-induced selective oxidation. Increased local photo-oxidation is found to result in the formation of extended horizontal micro- and nanostructures with fractal properties. Within a defined light intensity range, the structures reveal the azimuthal symmetry of the investigated crystal planes (111), (100), (110) and (113). The observed features could be reproduced using a model that is based on the interplay of stress in silicon, oxidation by light generated excess holes and locally increased etching in fluoride containing solution.
The International Linear Collider offers a lot of different interesting challenges concerning the physics of elementary particles as well as the development of accelerator and detector technologies. In this thesis, we investigate two rather separate topics - the precision measurement of the Higgs boson mass and of its coupling to the neutral gauge boson Z and the research and development of sensors for BeamCal, which is a sub-detector system of the ILC detector. After the Higgs boson has been found, it is important to determine its properties with high precision. We employ the Higgs-strahlung process for this purpose. A virtual Z boson is created in the electron-positron collisions, which emits a Higgs-boson while becoming on-shell. Using the so-called recoil technique, we determine the Higgs boson mass by reconstructing the Z boson momentum and using the center-of-mass energy of the colliding leptons. This technique allows to measure the Higgs boson mass without considering the Higgs boson decay, i.e. it can be applied even to a Higgs boson invisibly decaying. Monte-Carlo studies including a full detector simulation and a full event reconstruction were performed to simulate the impact of a realistic detector model on the precision of the Higgs boson mass and production cross-section measurement. Also, an analytical estimate of the influence of a given detector performance on the Higgs boson mass measurement uncertainty is given. We included a complete sample of background events predicted by the Standard Model, which may have a detector response similar to the signal events. A probabilistic method is used for the signal-background separation. Several other probabilistic methods were used to investigate and improve the measurement of the Higgs-strahlung cross-section and the Higgs boson mass from the recoil mass spectrum obtained after the signal-background separation. For a Higgs boson mass of 120 GeV, a center-of-mass energy of 250 GeV and an integrated luminosity of 50/fb, a relative uncertainty of 10% is obtained for the cross-section measurement, and a precision of 118 MeV for the Higgs boson mass. The original motivation to use the recoil technique for a Higgs boson mass measurement independent on its decay modes could not be completely confirmed. For a Higgs boson mass of 180 GeV and 350 GeV, a statistics corresponding to 50/fb is not sufficient to achieve the necessary significance of the recoil mass peak above the background. The BeamCal is a calorimeter in the very forward region, about 3 m away from the nominal interaction point and surrounding the beam pipe. Due to its location, a lot of beamstrahlung pair particles will hit this calorimeter, representing a challenge for the operational reliability of the sensors under such harsh radiation conditions. We investigated single-crystal and polycrystalline CVD diamond, gallium arsenide and radiation-hard silicon as sensor candidates for their radiation hardness and found that diamond and gallium arsenide are promising. We used a 10 MeV electron beam of few nA to irradiate the samples under investigation up to doses of 5 MGy for diamond, up to about 1.5 MGy for gallium arsenide and up to about 90 kGy for silicon. We measured in regular periods the CCD to characterize the impact of the absorbed dose on the size of the signal, which is generated by electrons of a Sr-90 source crossing the sensor. Additional measurements such as the dark current and the CCD as functions of the voltage completed the characterization of the sensor candidates. For the single-crystal CVD diamond, also the thermally stimulated current was measured to determine amongst others the defect density created by irradiation. In the diamond samples, evidence for strong polarization effects inside the material was found and investigated in more detail. A phenomenological model based on semi-conductor physics was developed to describe the sensor properties as a function of the applied electric field, the dose and the dose rate. Its predictions were compared with the results of the measurements. Several parameters such as time scales and cross-sections were determined using this model, which led to ongoing investigations.
This thesis presents the results of the research based on the Life Cycle Assessment (LCA), with respect to the application of the Energy-using Products (EuP) Directive and the Environmental Management System (EMS). In part A, an introduction and hypotheses of the research are given. In general it will be investigated, whether the environmental techniques such as Environmental Management System and Life Cycle Assessment may be used by the company in Poland as a tool for increasing the competitiveness and creation of the green company’s image. Furthermore, the applicability of these techniques and tools in the framework of the European directive on the Energy-using Products will be shown. In order to understand the requirements of the voluntary environmental tools and binding legal framework, a general description of the Environmental Management Systems (based on the ISO 14001 standards), Life Cycle Assessment (described by the ISO standards of 14040 family) as well as the Energy-using Products directive will be given in Part A. Part B will deal with the results of the LCA based on a case study of a gas-electro cooker produced by FagorMastercook S.A. The LCA evaluation was performed with the help of the SimaPro modelling program. The modelling was divided into two steps. In the first step, only the cooker’s influence on the environment was considered, including the production processes. In the second stage, the use phase processes were added, as well as End-of-Life scenarios specific for the Polish market and situation were applied. The evaluation was based on different Life Cycle Impact Assessment methods. As the result, one could observe, that main impact on the environment was caused by the subassemblies and materials with the highest weight. Furthermore, the use of the metals (ferro and non-ferro) was responsible for the majority of the environmental damage. This damage occurred mainly in the categories relating to the natural resource consumption. As for the second modelling stage, cooking and baking processes were pointed out as the main cause of the environmental damage from the life cycle perspective. The cooker itself had a relatively small importance and contribution to the overall impact. These LCA results were be used as a part of the comprehensive assessment of the environmental performance of the entire company system with the help of Sensitivity Model Prof. Vester (SMPV) software in Part C. The sensitivity analysis was performed in two steps. In the first step, all variables that could influence the functioning of the company (such as financial results, authorities, customers, environment, inhabitants of the city) were taken into consideration. In the second modelling step, only the variables with the most visible influence on the system were taken into consideration (i.e. price, owner, quality, etc.). For both modelling steps, several policy scenarios were developed, taking into consideration various types of interactions between variables and time spans of 15 and 30 years. As the result one could see, that the implementation of the LCA and EMS in the company may help to achieve the strategic goals, such as improvement of the products’ quality, creating the green image of the company, minimising costs and negative influence of the company on the environment. On the other hand, decision makers in the company should be aware of the implementation costs, which may cause the increase of the products’ price and the decrease of the competitiveness on the internal (Polish) and external (European) market. Subsequently, summary and conclusions of the results are presented in Part D. Parts A to D are described in the Volume 1 of the thesis. Appendices are presented in the Volume 2.
In this work, the electrical and luminescence properties of a series of Si based materials used for photovoltaics, microelectronics and nanoelectronics have been investigated by means of electron beam induced current (EBIC), cathodoluminescence (CL), photoluminescence (PL) and electroluminescence (EL). Photovoltaic Si produced by block casting has been investigated by EBIC on wafers sliced from different parts of the ingot. The impact of selected solar cell processing steps on the material properties has been evaluated by EBIC utilizing adjacent wafers from the ingot. The temperature dependence of dislocations’ EBIC contrast was measured to assess the degree of dislocation contamination with impurities, yielding low dislocation contamination for the middle of the block and high contamination in the top and bottom regions. This is in agreement with the impurity distribution in the block. It was found that phosphorus diffusion gettering (PDG) followed by SiN firing greatly reduces the recombination activity of extended defects at room temperature, and improves the bulk property simultaneously. The improvement is attributed to both PDG of metal impurities and a passivation effect of SiN firing. In order to better understand the factors limiting the properties of thin polycrystalline Si layers prepared by the Aluminum induced layer exchange (Alile) technique, epilayers grown on (111) and (100) monocrystalline Si substrates were used as a model system to investigate the impact of processing temperature (Ts) and type of substrate. It was found that no dislocations are formed for epilayers on (100) Si, while a high density of dislocations was detected on epilayers prepared on (111) Si at 450 °C. The dislocation density decreases with increasing TS. The diffusion lengths extracted from the energy dependent EBIC collection efficiencies reveal an improvement of the epilayer quality with increasing TS during growth from 450 °C to 650 °C, and a decrease of the epilayer quality at 700 °C. This is attributed to a reduction of the dislocation density with increasing TS and a formation of precipitates during the process. Precipitate formation of at 700 °C is limited because the metal impurities are very mobile at high TS, resulting in a homogeneous distribution of the impurities. Because the impurities are effective lifetime killers of the minority carriers, so the diffusion length decreases. PL measurements on epilayers grown on Si substrates revealed no characteristic dislocation-related luminescence (DRL) lines at room temperature and 77 K, while intense characteristic DRL lines D1 - D4 have been detected in the sample prepared by the Alile technique. This indicates that dislocations in the Alile sample are relatively clean. The possible reason for the purification of the Alile samples is Al induced gettering during the polycrystalline Si layer growth. The diffusion length in the thin top layer of Si-on-insulator (SOI) samples has been successfully measured by EBIC employing suppression of the surface recombination at the buried oxide layer and at surface of the top layer by biasing. The measured diffusion length is several times larger than the layer thickness. Dislocation networks produced by Si wafer direct bonding have been investigated with regard to their electrical properties by EBIC. The networks were observed to show charge carrier collection and electrical conduction. Inhomogeneities in the charge collection were detected in n- and p-type samples under appropriate beam energy. The EBIC contrast behavior can be understood under the consideration of the positively charged oxide precipitates along with dislocations charged with majority carriers, where the appearance of the contrast in dark or bright depends strongly on the ratio of the collection and the recombination loss of the carriers.The luminescence properties of Si nanostructures (Si nanowires, Si nano rods, porous Si, and Si/SiO2 multi quantum wells (MQWs)) are another important subject of this work. Sub-bandgap infrared (IR) luminescence around 1570 nm has been found in Si nanowires, nano rods and porous Si. PL measurements with samples immersed in different liquid media, for example, in aqueous HF (50%), concentrated H2SO4 (98%) and H2O2 established that the sub-bandgap IR luminescence originates from the Si/SiOx interface. Its origin was explained in terms of a simple recombination model through radiative interface states. EL in the sub-bandgap IR range has been observed in simple diodes prepared on porous Si and MQWs at room temperature. The results show the possibility to fabricate an efficient light emitter around 1570 nm wavelength based on the radiative recombination at the Si/Si oxide interface. Based on the knowledge about radiative transitions via the interface states, an improved understanding of luminescence in dislocated samples was proposed.
This thesis describes the complete design of a low cost 60 GHz front end in SiGe BiCMOS technology. It covers the topics of a system plan, designs of building blocks, designs of application boards and real environment tests. Different LNA and mixer topologies have been investigated and fabricated. Good agreements between measurements and simulations have been achieved by using the self-developed component models. A transceiver front end system is built based on these blocks. A heterodyne architecture with a 5 GHz IF is adopted because it is compatible with the standard IEEE 802.11a, which allows the reuse of some existing building blocks of the 5 GHz transceiver. The transceiver chips are assembled onto application boards and connected by bond-wires. Bond-wire inductances have been minimized by using a cavity and compensated by an on board structure. The front end has been tested by both QPSK and OFDM signals in an indoor environment. Clear constellations have been measured. This was the first silicon based 60 GHz demonstrator in Europe and the second in the world.
In the time of increased awareness about the environment problems by the public opinion and intensive international effort to reduce emissions of greenhouse gases, as well increase of the generation of electrical energy to facilitate industrial growth, the conference offers broad contribution towards achieving the goals of diversification and sustainable development. The scope of the Conference is to promote a Forum, where people involved with electrical power systems may exchange their experiences and present solutions found for actual and future problems. The conference offers prominent academics and industrial practitioners from all over the world the forum for discussion about the future of electrical energy and environmental issues and presents a base for identifying directions for continuation of research.
The research in this thesis focuses on different techniques which can improve efficiency of the symbolic analysis of Petri nets. Reduced ordered interval decision diagrams (ROIDDs) are employed to encode sets of states of k-bounded nets. We discuss implementation of an ROIDD package and special ROIDD operations needed in symbolic algorithms. We study then how to improve efficiency of the reachability analysis and propose a new saturation approach, which exploits the structure of ROIDDs and the structure of k-bounded P/T nets. It manages to keep sizes of intermediate diagrams smaller than other approaches and can drastically improve efficiency of the symbolic analysis. Saturation techniques are applied in the enumeration of strongly connected components and in model checking. Implementation of symbolic model checkers for k-bounded P/T nets are discussed. We consider CTL and a novel LTL model checker. A number of techniques to improve efficiency of the implementation are considered.
Financial globalization is an inherent feature of today’s economies. But the positive impact of financial globalization has been limited and some puzzling evidence has been found recently. To explain these puzzles, Stulz argued that finance is critically affected by Twin Agency Problems: firstly, the controlling shareholders can use their power for their own benefit but at the expense of outside investors. Secondly, the state rulers can use their power to improve their own welfare at the expense of all shareholders. When these agency problems worsen, diffuse ownership is inefficient and ownership concentration is the best choice. Ownership concentration inversely limits a country’s ability to benefit from financial globalization. On the basis of Stulz’s theory and remaining the central role of the Twin Agency Problems in fostering ownership concentration, this study relaxes some simplified assumptions in Stulz’s model and develops a more practical one. According to this developed model, the following solutions from the theoretical research are suggested for the government to solve the agency problems: improving the legal sense through education; increasing the expected profitability with active economic policies; strengthening the constraint on the expropriators through laws and regulations; implementing the above three strategies together; lastly, improving the investor protection during the development of financial market. This paper also makes an empirical investigation in China. On the basis of the data from 1481 Chinese companies listed in Shanghai, Shenzhen or New York, it is found that more than 70 % of the companies are ownership concentrated. More than halve of them are controlled by the state and nearly 20% are controlled by families. The average degree of ownership concentration in China is more than 30%, which is higher than most other Asian countries. It was argued that listing abroad can decrease the ownership concentration, but the evidence in China shows that the companies listed abroad are more concentrated than those listed only inland. The investigation of the profitability reveals that the companies listed abroad are not more profitable than those listed inland, but the difference of the profitability between these companies is much less, which means the companies listed abroad are more reliable as a whole, because bad companies are strictly forbidden to step into the market. The investigation of the relationship between capital scale and ownership concentration shows that the companies with greater capital scale are more concentrated and most of the giant companies are controlled by the government. Because in a country without advanced financial market the capital can be collected from the public is limited and the huge companies could only be financed by the state. The smaller companies are easier to become ownership dispersed. The research of the relationship between ownership concentration and profitability reveals that family held companies are more profitable than state held ones; the widely held companies have the lowest profitability. Although most of the dispersed companies have a poor performance, some of them are really good. The research of the ownership structures finds out that the companies with indirect dispersed structure or foundation held structure are more profitable and the deviation of profitability of these companies is much less than the pyramid structure. Another discovery is that most of the companies with indirect dispersed structure are held by hundreds of or even more than thousand of the employees of the listed company. The reasons why these companies are more profitable are the lower separation of voting rights from cash flow right and the more ownership encouragement. In the employee held companies, the ownership is dispersed to all the managers and almost all employees, and all of them are encouraged to do well and to act as monitors for each other. So, it is difficult for the top managers to steal from the company. Through all these empirical research the following suggestions to resolve the twin agency problems are obtained: not relying on foreign financial market but concentrating on the advancement of legal sense, laws and regulations inland; strictly examining the companies which apply to be listed on the exchange and prevent the bad companies from going into the market; beginning the decentralization of ownership with relative smaller companies; transforming the state holding company into employee holding dispersed company; eliminating or decreasing the separation of voting rights from cash flow rights; encouraging and supervising the managers by given more managers stocks or shares of the company.
Over the last decade or so, there has been an increasing need to acknowledge the role played by local resource users in environmental decision making and to incorporate their perceptions in the management of natural resources. This has led to the development of various methods of assessing environmental attitudes and of natural resource valuation. Most of these studies have been conducted in developed countries and have utilised economic methods of valuation. This study highlights the environmental attitudes and values of a very important group of stakeholders - women - and the significance of taking these into consideration in the management of local coastal natural resources. Using respondents from two Ghanaian coastal communities, Bortianor and Moree, the study also investigated poverty-coastal natural resource linkages and how this knowledge can be used to improve Natural Resource Management in Ghana. In proposing specific policy options for managing the coastal environment an examination of formal, informal institutional and legal framework was also done. Primary data was collected by means of focus group discussions, personal interviews and participant observations. A total of 304 women (151 from Bortianor and 153 from Moree) took part in the study. The results showed that the study communities had poor access to basic amenities such as potable water, schools, health facilities as well as basic sanitation services. Their livelihood patterns revolve around the availability of coastal natural resources such as fish and fuel wood. The attitudinal scale used to assess environmental attitudes achieved adequate internal consistency with Cronbach’s (1951) Alpha reliability coefficients of 0.729 in Bortianor and 0.735 in Moree. The environmental attitudes of respondents were overwhelmingly positive; this however did not match the state of affairs in the area. The study showed that positive attitudes do not always result in pro-environmental behaviour. In the study areas poverty, low educational levels and other social and cultural practices could also influence the ability of respondents to translate the generally positive environmental attitudes into positive environmental action. The section on environmental values assessed the environmental values of respondents through the relative importance they placed on the different benefits derived from coastal natural resources. It also prioritised environmental issues or concerns in the study areas from the perspectives of the respondents. Rather than use a simple ordinal ranking of all objects, the paired comparison approach was used. The study showed that in both areas respondents placed the greatest importance on the coastal natural resources as sources of wealth creation and food. When it came to environmental concerns, it was not surprising that issues of safe drinking water, available fish and good sanitation were most important to respondents. From the results it was argued that since coastal natural resources as sources of food and income ranked highest, developing activities and policies that add value to the fishery industry, generate income and improve the standard of living of respondents would be most effective. Improving their standard of living could shift their focus from more utilitarian values to that of more pro-natural resource values. After examining existing institutional capacities and respondents’ perceptions of who should manage local coastal natural resources, the study concludes by using the findings to make some practical policy recommendations.