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RF MEMS Switches with Novel Materials and Micromachining Techniques for SOC/SOP RF Front EndsWang, Guoan 03 August 2006 (has links)
This dissertation deals with the development of RF MEMS switches with novel materials and micromachining techniques for the RF and microwave applications. To enable the integration of RF and microwave components on CMOS grade silicon, finite ground coplanar waveguide transmission line on CMOS grade silicon wafer were first studied using micromachining techniques. In addition, several RF MEMS capacitive switches were developed with novel materials. A novel approach for fabricating low cost capacitive RF MEMS switches using directly photo-definable high dielectric constant metal oxides was developed, these switches exhibited significantly higher isolation and load capacitances as compared to comparable switches fabricated using a simple silicon nitride dielectric. The second RF MEMS switch developed is on a low cost, flexible liquid crystal polymer (LCP) substrate. Its very low water absorption (0.04%), low dielectric loss and multi-layer circuit capability make it very appealing for RF Systems-On-a-Package (SOP). Also, a tunable RF MEMS switch on a sapphire substrate with BST as dielectric material was developed, the BST has a very high dielectric constant (>300) making it very appealing for RF MEMS capacitive switches. The tunable dielectric constant of BST provides a possibility of making linearly tunable MEMS capacitor-switches. For the first time a capacitive tunable RF MEMS switch with a BST dielectric and its characterization and properties up to 40 GHz was presented. Dielectric charging is the main reliability issue for MEMS switch, temperature study of dielectric polarization effect of RF MEMS was investigated in this dissertation. Finally, integration of two reconfigurable RF circuits with RF MEMS switches were discussed, the first one is a reconfigurable dual frequency (14GHz and 35 GHz) antenna with double polarization using RF MEMS switches on a multi-layer LCP substrate; and the second one is a center frequency and bandwidth tunable filter with BST capacitors and RF MEMS switches on sapphire substrate.
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Zero-level Packaging Of Microwave And Millimeter-wave Mems ComponentsComart, Ilker 01 September 2010 (has links) (PDF)
This thesis presents realization of two shunt, capacitive contact RF MEMS switches and two RF MEMS SPDT switches for microwave and millimeter-wave applications, two zero-level package structures for RF MEMS switches and development trials of a BCB based zero level packaging process cycle.
Two shunt, capacitive contact RF MEMS switches for 26 GHz and 12 GHz operating frequencies are designed, fabricated and consistencies between fabricated devices and designs are shown through RF measurements. For the switch design at 26 GHz and at the operating frequency, return loss in the upstate is measured to be 27.61 dB, insertion loss and isolation in the downstate is measured to be 0.21 dB and 27.16 dB, respectively. For the switch design at 12 GHz and at the operating frequency, return loss in the upstate is measured to be 38.69 dB, insertion loss and isolation in the downstate is measured to be 0.05 dB and 25.84 dB, respectively. Quite accurate circuit models have been obtained for both of the RF MEMS switches. Two RF MEMS SPDT switches, which utilize the shunt, capacitive contact switches as building blocks are designed through circuit simulations. These two designs are fabricated and their RF measurements have been completed. It is shown from circuit model simulations that, the performances of the fabricated devices and desired responses corresponded to each other. For the SPDT switch design at 26 GHz, return loss at the input port is measured to be 12 dB and insertion loss is measured to be 1.24 dB. For the SPDT switch design at 12 GHz, return loss at the input port is measured to be 5.6 dB and insertion loss is measured to be 0.49 dB. The reason behind the unexpectedly bad performances has been investigated and discovered. The bad performances were due to a common mistake in the layouts of both SPDT switches. These mistakes are corrected in the circuit models and expected performances are obtained.
Two different zero-level package structures which use high-resistive Si wafers have been suggested and required design changes have been made on the RF MEMS shunt, capacitive contact switches and SPDT switches in order to minimize the package effects. For this purpose polygonal CPW transitions have been designed and integrated into the designs, followed by the necessary tunings in the switch structures for which EM and circuit simulations are utilized.
For the suggested package structures to be produced, two possible process cycles have been studied. One of the process flows was based on KOH anisotropic Si etching and the other one was based on DRIE (Deep Reactive Ion Etching). Great progress has been achieved in the latter process cycle, however this process cycle still needs some more study and it could not be completed in the time required for this thesis study.
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Engineering and improving a molecular switch system for gene therapy applicationsTaylor, Jennifer 24 January 2011 (has links)
Molecular switch systems that activate gene expression by a small molecule are effective technologies that are widely used in applied biological research. Previously, two orthogonal ligand receptor pairs (OLRP) were developed as potential molecular switch systems by modifying nuclear receptors, ligand-activated transcription factors, to bind and activate gene expression with the synthetic ligand LG335 and not with the natural ligand 9-cis retinoic acid (9cRA). The two OLRP previously discovered were RXR variant 130 (I268A, I310A, F313A, and L436F) (also known as GR130) and the RXR variant QCIMFI (Q275C, I310M, and F313I) and (also known as GRQCIMFI).
The OLRP were further developed into molecular switches to provide controlled gene expression and potentially benefit gene therapy applications by replacing the DNA binding domain (DBD) with a Gal4 DBD, a yeast transcription factor. Both molecular switches are able to bind Gal4 RE in response to LG335 and activate expression of a luciferase or GFP reporter gene in either a two- or one-component system. When characterizing the GR130 variant in the two-component system, no activation was observed with the natural ligand 9cRA, and the variant displayed a 19±5-fold activation and a 50 nM EC50 value in the presence of LG335. When the GRQCIMFI variant was evaluated in the two-component system, activation was observed in the presence of LG335 with a 10 nM EC50 value and a 6±2-fold induction, and 9cRA induced activation only at the highest concentration. The GRQCIMFI variant was also characterized with the one-component system containing the reporter gene GFP in a transient transfection as well as through retroviral transduction, displaying green fluorescence in 30% of the cells in the presence of 10 µM LG335.
Several attempts were made to improve the molecular switch system. The VP16 activation domain was fused to GRQCIMFI in an effort to increase the fold induction; however, the addition of the VP16 created a constitutively active protein. Another approach to improve the molecular switch incorporated error-prone PCR to discover a new variant, Q275C, I310M, F313I, L455M (QCIMFILM), which displayed a 10-fold increase in sensitivity towards LG335 with a 5 nM EC50 value. Examination of the L455 position in the crystal structure of RXR revealed this residue is located outside of the ligand binding pocket on helix 12 (H12), but is able to significantly enhance receptor function. In fact, the single variant, L455M, was able to enhance receptor activation, compensate for a nonfunctional variant, as well as influence coactivator association.
The long-term goal of this research is to develop a gene regulation system that would be used in human gene therapy trials. In the process of creating this system a deeper assessment of the nuclear receptor structure and function is made, which can be used for the enhancement and development of transcriptional regulation mechanisms.
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Physiology of Escherichia coli in batch and fed-batch cultures with special emphasis on amino acid and glucose metabolismHan, Ling January 2002 (has links)
<p>The objective of this work is to better understand themetabolism and physiology of<i>Escherichiacoli</i>(W3110) in defined medium cultures with thelong-term goal of improving cell yield and recombinant proteinproductivity.</p><p>The order of amino acid utilization in<i>E. coli</i>batch cultures was investigated in a medium with16 amino acids and glucose. Ser, Pro, Asp, Gly, Thr, Glu andAla were rapidly consumed and depleted at the end of theexponential phase, while His, Arg, Val, Met, Ile, Leu, Phe, Lysand Tyr were consumed slowly during the following linear growthphase. The uptake order correlated to the maximum specificconsumption rate. Of the rapidly consumed amino acids onlyglyine and threonine improved growth when added individually.Serine was the first amino acid to be consumed, but inhibitedglucose uptake initially, which presumably is related to thefunction of PTS. Valine inhibited cell growth could be releasedby isoleucine. The critical medium concentration of valinetoxicity was 1.5 - 3 µmol L<sup>-1</sup>. Valine uptake was associated with exchange ofisoleucine out of the cells.</p><p>Glycine significantly increased the cell yield,<i>Y</i><sub>x/s,</sub>and growth rate of<i>E. coli</i>in batch cultures in a glucose-mineral medium.Maximum effect occurred at pH 6.8, at 6 - 12 mmol L<sup>-1</sup>glycine, and below 1.15 g dw L<sup>-1</sup>.<sup>13</sup>C NMR technique was employed to identify [1-<sup>13</sup>C], [2-<sup>13</sup>C]and [1,2-<sup>13</sup>C]acetate in the cultures supplied with [2-<sup>13</sup>C]glycine. The NMR data revealed that littledegradation of added glycine occurred, and that serine/glycinebiosynthesis was repressed below 1.15 g dw L<sup>-1</sup>, implicating that glycine was a source ofglycine, serine, one-carbon units, and threonine. Above 1.15 gdw L<sup>-1</sup>, 53% of the consumed glycine carbon was excretedas acetate. Degradation of glycine was associated with anincreased uptake rate, cleavage by GCV, and degradation of bothglycine- and glucose-derived serine to pyruvate. This switch inmetabolism appears to be regulated by quorum sensing.</p><p>A cell density-dependent metabolic switch occurred also inthe central metabolism. A 2 - 3 fold decrease in mostglycolytic and TCA cycle metabolites, but an increase inacetyl-CoA, occurred after the switch. The acetate productionrate decreased throughout the culture with a temporary increaseat the switch point, but the intracellular acetate poolremained relatively constant.</p><p>Two mixtures of amino acids were fed together with glucosein fed-batch cultures of<i>E. coli</i>W3110 pRIT44T2, expressing the recombinantprotein ZZT2. One mixture contained 20 amino acids and theother 5 so-called 'protein amino acids': Ala, Arg, Met, His andPhe. Although the amino aids increased the cell yield anddecreased the proteolysis rate in both cases, ZZT2 productionwas decreased. A decrease of ZZT2 synthesis rate is consideredto be the reason. Further studies of the 5 amino acidsindicated that a few amino acids disturb metabolism.</p><p>Carbon mass balances were calculated in glucose limitedfed-batch cultures of<i>E. coli</i>. In the end, the carbon recovery was ~90% basedon biomass, CO<sub>2</sub>and acetate, but ~100% if the all carbon in themedium was included. Outer membrane (OM) constituents,lipopolysaccharide, phospholipids, and carbohydratescontributed to 63% of the extracellular carbon. Little celllysis occurred and the unidentified (~30%) carbon was assumedto constitute complex carbohydrates. A novel cultivationtechnique Temperature-Limited Fed-Batch (TLFB) is developed toprevent OM shedding in high-cell density cultures.</p><p><b>Keywords</b>: Escherichia coli, amino acids, glycine, quorumsensing, metabolic switch, metabolite pools, carbon balance,outer membrane, lipopolysaccharide, batch culture, fed-batchculture</p>
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Millimeter-wave integrated circuit design in silicon-germanium technology for next generation radarsSong, Peter 08 June 2015 (has links)
In this thesis, the circuits which comprise the front-end of a millimeter-wave transmit-receive module are investigated using a state-of-the-art 90 nm SiGe BiCMOS process for use in radar remote sensing applications. In Chapter I, the motivation for a millimeter-wave radar in the context of space-based remote sensing is discussed. In addition, an overview of Silicon-germanium technology is presented, and the chapter concludes with a discussion of design challenges at millimeter-wave frequencies. In Chapter II, a brief history of radar technology is presented - the motivations leading to the development of the transmit-receive module for active electronically scanned arrays are discussed, and the critical components which reside in nearly every high-frequency transmit-receive module are introduced. In Chapter III, the design and results of a W-band single-pole, double-throw switch using SiGe p-i-n diodes are discussed. In particular, the design topology and methods used to achieve low-loss and high power handling over a wide matching bandwidth without sacrificing isolation are described. In Chapter IV, the design and results of a W-band low-noise amplifier using SiGe HBT's are discussed. The design methodologies used to achieve high gain and exceptional noise performance over a wide matching bandwidth are described. Concluding remarks and a discussion of future work are in Chapter V.
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“Should I switch?” Controversies created by an advice columnLehman, Sandra Elizabeth 05 January 2011 (has links)
In 1990’s, the circumstances of being a contestant on a popular game show were published in a trendy question and answer column in Parade Magazine. If contestant switched from the initial choice to a second choice offer by the host, would the chances of winning the desired prize be increase? The columnist’s response to the reader sparked a good deal of controversy among mathematicians. Shortly after the publication of this answer, articles appeared in various mathematical publications some supporting and some refuting the columnist’s answer.
This document reports the results of research into the controversy generated by some of the probability problems used on Let’s Make a Deal game show. Using a variety of approaches and assumption, the author attempts to formulate mathematical proof to explain the correct answer to the contestant’s question, “Should I switch?” / text
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Analysis of high performance interconnect in SoC with distributed switches and multiple issue bus protocolsNarayanasetty, Bhargavi 26 July 2011 (has links)
In a System on a Chip (SoC), interconnect is the factor limiting Performance,
Power, Area and Schedule (PPAS). Distributed crossbar switches also called as
Switching Central Resources (SCR) are often used to implement high performance
interconnect in a SoC – Network on a Chip (NoC). Multiple issue bus protocols like AXI
(from ARM), VBUSM (from TI) are used in paths critical to the performance of the
whole chip. Experimental analysis of effects on PPAS by architectural modifications to
the SCRs is carried out, using synthesis tools and Texas Instruments (TI) in house power
estimation tools. The effects of scaling of SCR sizes are discussed in this report. These
results provide a quick means of estimation for architectural changes in the early design
phase. Apart from SCR design, the other major domain, which is a concern, is deadlocks.
Deadlocks are situations where the network resources are suspended waiting for each
other. In this report various kinds of deadlocks are classified and their respective mitigations in such networks are provided. These analyses are necessary to qualify
distributed SCR interconnect, which uses multiple issue protocols, across all scenarios of
transactions. The entire analysis in this report is carried out using a flagship product of
Texas Instruments. This ASIC SoC is a complex wireless base station developed in 2010-
2011, having 20 major cores. Since the parameters of crossbar switches with multiple
issue bus protocols are commonly used in SoCs across the semiconductor industry, this
reports provides us a strong basis for architectural/design selection and validation of all
such high performance device interconnects.
This report can be used as a seed for the development of an interface tool for
architects. For a given architecture, the tool suggests architectural modifications, and
reports deadlock situations. This new tool will aid architects to close design problems and
bring provide a competitive specification very early in the design cycle. A working
algorithm for the tool development is included in this report. / text
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Stochastic modeling and simulation of biochemical reaction kineticsAgarwal, Animesh 21 September 2011 (has links)
Biochemical reactions make up most of the activity in a cell. There is inherent stochasticity in the kinetic behavior of biochemical reactions which in turn governs the fate of various cellular processes. In this work, the precision of a method for dimensionality reduction for stochastic modeling of biochemical reactions is evaluated. Further, a method of stochastic simulation of reaction kinetics is implemented in case of a specific biochemical network involved in maintenance of long-term potentiation (LTP), the basic substrate for learning and memory formation. The dimensionality reduction method diverges significantly from a full stochastic model in prediction the variance of the fluctuations. The application of the stochastic simulation method to LTP modeling was used to find qualitative dependence of stochastic fluctuations on reaction volume and model parameters. / text
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Meticulous control of the T3SS of Yersinia is essential for full virulence / Minutiös kontroll av Yersinias T3SS är essentiellt för fullständig virulensBjörnfot, Ann-Catrin January 2011 (has links)
The type III secretion system (T3SS) of pathogenic Yersinia pseudotuberculosis is involved in virulence. The syringe-like secretion system spans both bacterial membranes and is responsible for the ability of Yersinia to transfer toxic proteins (Yop proteins) into the eukaryotic target cell. The T3SS is believed to have evolved from the flagellum and regulation of the T3SS is a complex event that involves a series of regulatory proteins, whereby two are YscP and YscU. In a regulatory model, called the substrate specificity switch, both proteins act together to ensure proper T3SS structure and function by regulating a stop in YscF needle protein export with a shift to Yop effector secretion. YscU undergoes autoproteolysis at a conserved motif consisting of amino acids Asparagine-Proline-Threonine-Histidine (NPTH). Processing generates a C-terminal 10 kDa peptide, YscUCC. Processing is crucial for proper T3SS regulation and function both in vitro and in vivo. Full-length YscU does not support Yop secretion and after cleavage, YscUCC remains attached to the rest of YscU and acts as a negative block on T3S. Relief of this negative block is suggested to occur through displacement of YscUCC from the rest of YscU. Thorough control of many different cellular processes is brought by the heat shock proteins (HSPs) DnaK and DnaJ. Due to their multiple regulatory functions, mutations in the hsp-genes lead to pleiotropic effects. DnaK and DnaJ are essential for proper flagellum driven motion of bacteria, but more so; they ensure proper Yersinia T3SS function in vivo. Furthermore, DnaJ interacts with YscU and may be directly involved in T3SS regulation. Virulence of Yersinia is regulated on many levels. A previously identified virulence associated protein, VagH, is now characterized as an S-adenosyl-methionine dependent methyltransferase. The targets of the methylation activity of VagH are release factors 1 and 2 (RF1 and RF2), that are important for translation termination. The enzymatic activity of VagH is important for Yop secretion and a vagH mutant up-regulates a T3SS negative regulatory protein, YopD. Furthermore, a vagH mutant is avirulent in a mouse infection model, but is not affected in macrophage intracellular survival. The importance of VagH in vivo makes it a possible target for novel antimicrobial therapy.
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What would be the efficient ways for Switch Pac to increase potential demand and capitalize on green attitudes and behavior in the Swedish market?Curtolo, Anna, Bruning, Andrea January 2008 (has links)
Date: 6/16/2008 Institution: School of Sustainable Development of Society and Technology, Mälardalen University, Västerås (Sweden) Authors: Brüning, Andrea 830111 Västerås Curtolo,Anna 820517 Västerås Tutor: Tobias Eltebrandt Title: A Study of Switch Pac: what would be the efficient ways for Switch Pac to increase potential demand and capitalize on green attitudes and behavior in the Swedish market? Problem: What would be the efficient ways for Switch Pac to increase potential demand and capitalize on green attitudes and behavior in the Swedish market? Purpose: The aim of our project is to see the potential of Switch Pac’s oxo-biodegradable plastic bags on the Swedish market by capitalize on green attitudes and behaviour. Method: The report is based on primary data collected through questionnaires (end consumer/ B2B customers). For the investigation of Switch Pac’s macro- and microenvironment secondary data was used (books, journals, newspaper and the Internet) Conceptual Framework: The conceptual framework consists of certain models to investigate the following topics: Consumer behavior AIDA-Model STP-Model Switch Pac´s business environment PESTEL Conclusion/ Recommendations: In our conclusion based on our frameworks PESTEL, AIDA and STP we concluded that peoples’ awareness regarding environmental friendly plastic bags are not very high based on our questionnaire. The efficient ways for Switch Pac to increase potential demand is to target the customer in the age range from 20 – 49 years and cooperate with supermarkets and (department) stores. Furthermore, Switch Pac needs to position its products in the consumers mind through create brand awareness by using certain elements of the marketing mix model.
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