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Fabrication of Si-based Suspending Antenna by Bulk-micromachining and Surface-micromachining TechnologiesHsu, Kuo-Yi 02 September 2010 (has links)
For the application of 802.11a wireless communication system, this thesis aims to develop a novel suspending antenna with periodic structures to reduce electromagnetic wave from substrate using electrochemical deposition, surface micromachining and bulk micromachining technologies.
This research presents two particular structures to increase the bandwidth and the radiation efficient and to reduce the return loss of the antenna, including: (i) the optimum design of periodic structures to restrain electromagnetic wave from substrate and to reduce the return loss of the antenna. To reduce the effective dielectric constant of the silicon substrate and to increase the bandwidth of the antenna, anisotropic etching the backside of the silicon substrate formed regular cavities using bulk-micromachining technology, (ii) to utilize a suspending structure to reduce the power loss through the substrate and to confirm the result using high frequency simulator.
The implemented Si-based suspending antenna with periodic structures were characterized by a commercial network analyzer under 1~8 GHz testing frequency range. All the bandwidth and the return loss of the antenna proposed in this thesis are extracted by the commercial simulation software. Based on the measurement results, the center frequency is equal to 4.85 GHz, the return loss is around -35.5 dB and the bandwidth is equal to 42.9% (3.75~5.8 GHz). Eventually, this thesis successfully develops a low-loss and broadband antenna with novel structures using high frequency simulator and MEMS technologies for 802.11a wireless communication system.
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Development of a Balun with Suspending Structure by MEMS TechnologyDeng, Yu-Ting 16 November 2011 (has links)
Balun is a key component in radio frequency (RF) circuits. The conventional Si-based planar spiral balun presented a high insertion loss. To solve this problem, this thesis firstly develops a Si-based suspending spiral balun using electrochemical deposition and surface micromachining technology for the fourth generation of wireless communication system.
To reduce the power dissipation of the conventional Si-based planar spiral balun, thesis utilized a suspending structure to reduce the power loss through the substrate and dielectric layer. The fabricated suspending spiral balun are constructed by three bottom GSG electrodes, thirty three supporting copper vias and a suspending spiral copper conducting layer. The main fabrication processes in this research including: (1) four thin-film deposition processes, (2) four photolithography processes, (3) two etching processes and (4) two copper electroplating processes. In addition, this thesis used the commercial software (Ansoft HFSS) to analysis the high frequency characteristic of Si-based suspending spiral balun.
The finished Si-based suspending spiral balun were measured by a commercial network analyzer under 2~8 GHz testing frequency range. Based on the measurement results, the value of insertion loss is 1.26 dB at 5.2 GHz, magnitude imbalanced is lower than 0.86 dB, phase imbalanced is less than 3.4 degree and CMRR is more than 30 dB. Finally, this thesis successfully develops a Si-based suspending spiral balun using MEMS technology for the fourth generation wireless communication system.
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Design and Simulation of High Quality-factor Microinductors for Wireless Communication System ApplicationsHung, Kun-ting 11 August 2008 (has links)
This paper aims to design a high-quality-factor suspending micro-inductor and to establish its equivalent circuit model for performance optimization. Two commercial software (Ansoft HFSS and Agilent ADS) are adopts to analysis the influences of quality factor on the geometric parameters and substrate materials. The designed micro-inductors are constructed by one bottom GSG electrode, two supporting copper vias and a spiral suspending copper conducting layer.
As the simulated results of this research, the quality factor of the suspending micro-inductor is increased with the height of air gap, the thickness and width of suspending copper conducting layer and decrease with the number of turns, line space and outer diameter of suspending copper conducting layer. The influences of different shapes of the spiral suspending copper conducting layers on the quality factor of micro-inductors were also investigated. The simulation results well match to the theoretical prediction.
Finally, this thesis has successfully derived two experiential formulas based on the analysis results to estimate quickly the inductance of the suspending micro-inductors with circular and square shape. Compared with the simulation results and realistic measurement results, these experiential formulas demonstrate 94-95% and 90% accuracies respectively.
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Development of Micro-transformer by MEMS Technology for Microwave Communication SystemSun, Chian-Hao 28 July 2012 (has links)
The conventional planar micro transformers presented very low quality-factor (Q<10) and very high insertion loss (-6 ~ -10 dB) at high operation frequency since most of the microwave power is dissipated through the silicon substrate. To increase the quality-factor and reduce the insertion loss of silicon-based transformers, this dissertation presents a two-port and three-port micro transformers with suspending structure utilizing the micro-electro-mechanical systems (MEMS) technology. The proposed silicon-based transformers are constructed by two winding and suspending micro inductors. Each suspending micro inductor consists of a 0.32 µm-thick TaN/Ta/Cu bottom electrode, a 10 µm-height supporting copper vias and a 6 µm-thick spiral copper conducting layer.
This research adopts the Taguchi method and commercial electromagnetic simulation software (Ansoft-HFSS) to optimize the dimensional specifications of the copper conducting layer. Many high frequency characteristics of the suspending micro transformers are simulated, including the inductance, the magnetic coupling factor, the quality-factor, the magnitude imbalance, the phase imbalance, the common mode rejection ratio (CMRR) and the insertion loss. In this research, the surface micromachining and electrochemical deposition techniques are used to implement the suspending micro transformers. The main fabrication steps include five photolithography and eight thin-film deposition processes.
According to the simulation and measurement results from the commercial network analyzer (Agilent-E8364B) and software (Agilent-ADS), the implemented two-port transformer demonstrates a high magnetic coupling factor (0.78) and a very high quality-factor (Q=17.20) at 5.2 GHz. On the other hand, the proposed three-port transformer presents a low magnitude imbalance (-0.02 dB), a low phase imbalance (1.65¢X), a high CMRR (36.78 dB) and a very low insertion loss (-4.52 dB) under the same operation frequency. In this dissertation, a novel suspending micro transformer has been developed and characterized. The proposed micro transformer is very suitable for being used in the portable microwave communication system due to its small chip size (0.7 mm¡Ñ0.7 mm¡Ñ0.5 mm) and excellent high-frequency characterization.
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Design and Fabrication of High Quality-factor Suspending MicroinductorsJiang, Zong-Nan 27 August 2008 (has links)
For the application of 4G wireless communication system, this thesis
aims to develop a high-quality-factor and low-power-dissipation
suspending micro-inductor using electrochemical deposition and surface
micromachining technologies.
This research presents three technical points to improve the quality
factor and reduce the power dissipation of micro inductor, including (i) to
adopt a low resistivity material (copper) as the conducting layer to
decrease the Eddy current due to the skin effect and reduce the total series
resistance and energy loss, (ii) to utilize a suspending structure to
diminish the power loss through the substrate and (iii) to replace the
silicon wafer with a high resistance substrate (Corning 7740) to compress
effectively the power dissipation in high frequency operation.
The implemented suspending micro-inductors were characterized by a
commercial network analyzer (Agilent E5071C) under 0.5~20 GHz
testing frequency range. All the inductances and quality factors of the
micro-inductors proposed in this thesis are extracted by the Agilent ADS
software. The optimized value of the quality factor is around to 24.9 and
the corresponding inductance is equal to 5.43 nH .
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Polymeric Complexes and Composites for Aerospace and Biomedical ApplicationsZhang, Rui 01 August 2018 (has links)
Polymers, among metals and ceramics, are major solid materials which are widely used in all kinds of applications. Polymers are of particular interest because they can be tailored with desirable properties. Polymer-based complexes and composites, which contain both the polymers and other components such as metal oxide/salts, are playing a more and more important role in the material fields. Such complexes and composites may display the benefits of both the polymer and other materials, endowing them with excellent functionalities for targeted applications.
In this dissertation, a great deal of research was conducted to synthesize novel polymers and build polymeric complexes and composites for biomedical and aerospace applications. In chapter 3, two methods were developed and optimized to fabricate sub-micron high-performance polymer particles which were subsequently used to coat onto functional carbon fibers via electrostatic interactions, for the purpose of fabricating carbon fiber reinforced polymer composites. In chapter 4, a novel Pluronic® P85-bearing penta-block copolymer was synthesized and formed complexes with magnetite. The complexes displayed non-toxicity to cells normally but were able to selectively kill cancer cells without killing normal cells when subjected to a low-frequency alternating current magnetic field. Such results demonstrated the potential of such polymeric complexes in cancer treatment. Chapter 5 described the synthesis of several ionic graft copolymers primarily bisphosphonate-containing polymers, and the fabrication of polymer-magnetite complexes. The in-depth investigation results indicated the capability of the complexes for potential drug delivery, imaging, and other biomedical applications. Chapter 6 described additional polymer synthesis and particle or complex fabrication for potential drug delivery and imaging, as well as radiation shielding. / PHD / Polymers, metals, and ceramics are three major classes of solid materials that are used every day and everywhere. Polymers are of particular significance because they can be tailored to possess certain desirable properties, and, hence, they are playing a more and more important role as substitutes for metals and ceramics in a wide array of applications. Engineering and high-performance polymers were synthesized with excellent properties for biomedical and aerospace applications.
Polymers can be fabricated into composites and complexes which contain not only polymers but also other materials, such as metal oxides/salts, carbon fibers, glass fibers, etc. When composites and complexes are made with sufficient stability, the materials may display the advantages of each component, making them more promising for specific applications.
In this dissertation, effort was focused on developing versatile polymer-based complexes and composites for aerospace and biomedical applications. Chapter 3 describes the fabrication of sub-micron high-performance polymer particles by two methods and they were subsequently coated onto functional carbon fibers for making composites. Chapter 4 describes the synthesis of a novel copolymer that formed complexes with magnetite nanoparticles. The complexes were able to selectively kill cancerous cells without killing normal cells when exposed to an external magnetic field, and thus these materials have potential for cancer treatment. Chapter 5 describes the fabrication of phosphonate-bearing ionic copolymer-magnetite complexes and their potential applications in drug delivery, imaging, and other biomedical applications. Chapter 6 describes the synthesis of polymers and their corresponding complexes for potential drug delivery and imaging, as well as potential radiation shielding applications.
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GPU-accelerated Model Checking of Periodic Self-Suspending Real-Time TasksLiberg, Tim, Måhl, Per-Erik January 2012 (has links)
Efficient model checking is important in order to make this type of software verification useful for systems that are complex in their structure. If a system is too large or complex then model checking does not simply scale, i.e., it could take too much time to verify the system. This is one strong argument for focusing on making model checking faster. Another interesting aim is to make model checking so fast that it can be used for predicting scheduling decisions for real-time schedulers at runtime. This of course requires the model checking to complete within a order of milliseconds or even microseconds. The aim is set very high but the results of this thesis will at least give a hint on whether this seems possible or not. The magic card for (maybe) making this possible is called Graphics Processing Unit (GPU). This thesis will investigate if and how a model checking algorithm can be ported and executed on a GPU. Modern GPU architectures offers a high degree of processing power since they are equipped with up to 1000 (NVIDIA GTX 590) or 3000 (NVIDIA Tesla K10) processor cores. The drawback is that they offer poor thread-communication possibilities and memory caches compared to CPU. This makes it very difficult to port CPU programs to GPUs.The example model (system) used in this thesis represents a real-time task scheduler that can schedule up to three periodic self-suspending tasks. The aim is to verify, i.e., find a feasible schedule for these tasks, and do it as fast as possible with the help of the GPU.
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A scanning ion conductance microscopy assay to investigate interactions between cell penetrating peptides and pore-suspending membranesSaßen, Christoph 22 October 2013 (has links)
Die Rasterionenleitfähigkeitsmikroskopie (scanning ion conductance microscopy, SICM) stellt eine kontaktfreie Methode zur Ermittlung sowohl der Topographie als auch lokalen Ionenleitfähigkeit einer Oberfläche dar. Besonders vorteilhaft ist die Vermeidung mechanischer Beeinflussung bei der Untersuchung flexibler Strukturen, z.B. Lipiddoppelschichten wie Zellen oder künstlich erzeugter Lipidmembranen. Porenüberspannende Membranen (pore-suspending membranes, PSMs) verbinden als ein Beispiel für Modellsysteme eine hohe Stabilität mit lateraler Mobilität und dem Vorhandensein wässriger Kompartimente ober- und unterhalb der Doppelschicht, wie sie auch in der Natur gefunden werden. Ein wichtiges Forschungsgebiet stellt die Untersuchung der Wechselwirkung von Peptiden, besonders zellpenetrierenden Peptiden (cell penetrating peptides, CPPs), mit Lipiden und anderen Membranbestandteilen dar. Häufig untersuchte Beispiele sind Melittin, Hauptbestandteil des Giftes der Honigbiene Apis mellifera, sowie Penetratin, dritte Helix der Antennapedia Homöodomäne von Drosophila melanogaster.
Generalisierte Protokolle zur Herstellung lösungsmittelfreier PSMs werden vorgestellt. Riesige unilamellare Vesikel (giant unilamellar vesicles, GUVs) unterschiedlicher Lipidzusammensetzung wurden hierzu auf porösem Siliziumnitrid (Si3N4), welches mit Cholesterylpolyethylenoxythiol (CPEO3, hydrophob) bzw. Mercaptoethanol (ME, hydrophil) funktionalisiert worden war, gespreitet. Verwendet wurden GUVs aus reinen Phosphatidylcholin (PC)-Lipiden sowie aus Mischungen von PC-Lipiden mit Cholesterol und PC-Lipiden mit Phosphatidylserin (PS)-Lipiden. Der Erfolg des Spreitvorgangs wurde durch Abbilden mittels konfokaler Rasterlasermikroskopie (confocal laser scanning microscopy, CLSM) und SICM verifiziert.
Der Hauptteil dieser Arbeit behandelte die Entwicklung und Anwendung CLSM- und SICM-basierter CPP-Titrationsassays zur Aufklärung des Einflusses der Substratfunktionalisierung und der Lipidzusammensetzung der Membranen auf die Wechselwirkung zwischen Melittin bzw. Penetratin und den Lipiddoppelschichten. CLSM-Experimente wurden mit Melittin auf allen zur Verfügung stehenden PSMs sowohl auf hydrophob als auch hydrophil funktiona-lisierten Substraten durchgeführt, während Penetratin auf den drei unterschiedlichen PSMs auf hydrophil funktionalisierten Substraten verwendet wurde. Ein Reißen der Membranen wurde im Fall hydrophil funktionalisierter Substrate für beide Peptide im Bereich von 1–3 µM beobachtet. Bei hydrophob funktionalisierten Substraten induzierte eine dreifach geringere Melittinkonzentration die Zerstörung der Membranen. Sowohl auf hydrophob als auch auf hydrophil funktionalisierten Substraten wurde bei einem Cholesterolanteil von 10% eine Erhöhung der zum Reißen notwendigen Melittinkonzentratin erhalten, während bei 20% PS-Anteil eine Verschiebung zu geringeren Konzentrationen evident wurde. SICM-Experimente wurden mit Melittin auf PC/Cholesterol-PSMs auf hydrophob und hydrophil funktionalisierten Substraten und mit reinen PC-PSMs auf hydrophil funktionalisierten Membranen durchgeführt. Es wurden keine signifikanten Konzentrationsunterschiede beobachtet; die gefundenen Konzentrationsbereiche jedoch stimmten mit denen der CLSM-Experimente überein. Darüberhinaus wurde vor dem Reißen der Membranen ein Ansteigen der Porentiefe gefunden, das mit einer erhöhten Membranpermeabilität korrespondiert.
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The impact of suspending labor status on organizational culture of uniformed personnel of public administration in Greece. The case study of Municipal PoliceParaskevas, Theodoros 22 July 2022 (has links)
La cultura organizacional es un fenómeno multidimensional que desempeña un papel importante tanto en las organizaciones públicas como privadas, ya que explica “cómo se hacen las cosas” en el entorno de cada organización, mientras que sus variaciones afectan a casi todo en el funcionamiento de las organizaciones. Las organizaciones tienen que hacer frente a transformaciones externas e internas, y en este proceso pueden producirse todo tipo de cambios, ya que los directivos y los empleados dejan atrás una situación anterior para pasar a una situación nueva que teóricamente se considera mejor o más beneficiosa. Un cambio no siempre tiene el mismo sentido para los miembros de la organización, ya que la percepción del cambio puede variar entre los distintos integrantes de la misma. En este sentido, cada cambio puede desencadenar un sinfín de expectativas negativas o positivas, relacionadas con la percepción de los miembros de la organización sobre los beneficios, las amenazas, las pérdidas, las transferencias de poder y las ganancias que se producirán. Además, la percepción del cambio por parte de cada empleado genera toda una serie de sentimientos, pensamientos e intenciones de comportamiento frente al cambio, en función del estrés del empleado provocado por el propio cambio. La reacción afectiva, cognitiva y conductual del personal ante los futuros cambios impuestos guarda relación con los precedentes y con la cultura organizativa imperante. En nuestro estudio, se investigan estos aspectos pero circunscritos al caso de un servicio del sector público. Investigamos cómo la percepción del cambio por parte de los empleados afecta a su estrés, así como el papel mediador de su cultura en la relación cambio-estrés. Más específicamente, esta investigación gira en torno al personal uniformado de la Administración del Gobierno Local, en concreto de la agencia de la Policía Municipal. Nuestros hallazgos muestran la existencia de repercusiones en el estrés de los empleados tras un cambio radical, excesivo y masivo en el statu quo de su servicio. La mezcla prominente de culturas del personal influye en la forma en que el cambio afecta al estrés del personal uniformado. La cultura burocrática-empresarial actúa como un factor directo e indirecto que reduce el estrés de los empleados, mientras que la cultura autoritaria-tecnocrática coexistente aumenta el nivel de estrés. También se examinan otros componentes de la cultura organizacional, como la moral de los empleados, el compromiso y la satisfacción en el trabajo, otros elementos que tienen una importante relación con la adaptación de los empleados a la organización como el rendimiento, el cumplimiento de los objetivos organizacionales y la eficacia, así como la relación de éstos con la cultura. Se ha comprobado que la moral y el compromiso de los empleados parecen verse afectados positivamente por tipos de cultura como la burocrática-empresarial y la autocrática-empresarial, pero que disminuyen con las culturas autoritaria-tecnocrática y burocrática-autocrática, o que no están relacionados en lo que respecta al compromiso con el último tipo de cultura. Además, se confirman las relaciones positivas de la moral con el compromiso y la satisfacción laboral. No se ha encontrado un papel mediador directo, sino sólo indirecto, de la moral en la relación entre la satisfacción laboral de los empleados y el compromiso de los mismos, al mismo tiempo que existe una mediación indirecta de la moral de los empleados en el modo en que la cultura burocrática-empresarial tiene un efecto positivo en el compromiso de los empleados y también la mediación indirecta de la moral en la influencia negativa de la cultura autoritaria-tecnocrática en el compromiso de los empleados.
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Stabilität und laterale Mobilität von porenüberspannenden Membranen auf porösen Siliziumsubstraten / Stability and lateral mobility of pore-suspending membranes on porous silicon substratesWeiskopf, Daniela 30 April 2009 (has links)
No description available.
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