111 |
Analýza transportních a šumových charakteristik oxidových vrstev na bázi niobu / Noise and Transport Analysis of the Niobium Oxide LayersSita, Zdeněk January 2015 (has links)
Kondenzátor na bázi oxidu niobu je novým typem pasívní součástky, jehož vývoj byl motivován snahou vyřešit hlavní nedostatky tantalového kondenzátoru – omezený zdroj tantalové suroviny a nebezpečí hoření při průrazu. Chování kondenzátoru na bázi oxidu niobu lze stejně jako u tantalového kondenzátoru popsat prostřednictvím reverzní MIS struktury. Pro studium mechanismu transportu nosičů nábojů v dielektriku Nb2O5 a pro stanovení fyzikálních parametrů, které řídí zbytkový proud, bylo využito měření V-A charakteristik v normálním a reverzním módu při 77 a 300K, dále závislosti kapacity ochuzené vrstvy na napětí a frekvenci, teplotní a časové závislosti zbytkového proudu a spektrální hustoty šumu ve frekvenční a časové doméně při různých napětích. Experimentální data potvrdila platnost navrženého pásového diagramu MIS struktury a poskytla jeho klíčové parametry. Bylo ověřeno, že transport nosičů náboje v NbO kondenzátorech je určen ohmickou, Poole-Frenkelovou a tunelovou složkou v normálním módu, a Schottkyho emisí v reverzním módu. V rozsahu standardních aplikačních napětí dominují v normálním módu Poole-Frenkelova emise a v reverzním módu Schottkyho emise. Při vyšších napětích v normálním módu určuje průrazné napětí kondenzátoru tunelový mechanismus. V reverzním módu rozhoduje o odolnosti vůči tepelnému průrazu kondenzátoru výška bariéry mezi dielektrikem a anodou. Bylo zjištěno, že NbO a Tantalové kondenzátory mají stejný mechanismus vodivosti. Specifika NbO anody se projevují pouze v rozdílných hodnotách parametrů pásového diagramu, nikoliv v principech mechanismu transportu nosičů náboje. To vysvětluje základní rozdíl mezi oběma kondenzátory, který je v kvalitě dielektrické vrstvy na přechodu anody a dielektrika. Nižší potenciálové bariéry a vyšší počet defektů v dielektriku, který je způsoben dalším stabilním oxidem, má za následek vyšší zbytkový proud NbO kondenzátoru. Tento jev však nemá žádný vliv na spolehlivost součástky. Teoretické modely a vybrané testovací metody byly použity k volbě vhodných materiálů anody, ke stanovení vhodných dopantů a k optimalizaci technologie anodické oxidace. Byla nalezena korelace mezi parametry transportu nosičů náboje a spolehlivostí, a na základě experimentálních dat byly navrženy optimalizace výrobního procesu kondenzátorů. Lepší porozumění transportním mechanismům v NbO kondenzátorech umožnilo úplný popis nové součástky na bázi oxidu niobu. Byly zdůrazněny silné a slabé stránky této nové technologie a nalezeny nástroje pro optimalizaci procesů, které umožní vyšší spolehlivost a efektivitu NbO kondenzátorů.
|
112 |
Elektrodepozice tenkých tantalových vrstev z iontových roztoků a měření jejich elektrických vlastností / Electrodeposition of thin tantalum layers from ionic liquids and measurement of their electrical propertiesSvobodová, Ivana January 2016 (has links)
The thesis is focused on the electrodeposition of tantalum from ionic solution 1-butyl-1- methylpyrrolidinium bis(trifluoromethylsulfonyl) imide, ([BMP]Tf2N) at 200°C and description of related transfer and kinetic phenomena on the interface between the ionic solution and working electrode. Furthermore, the electrodeposition of tantalum layers in different ionic solutions containing tantalum salts and especially in ([BMP]Tf2N) is introduced. In the last part of the thesis, results of cyclic voltammetry, surface analysis SEM and elemental analysis EDX are discussed. MIS (metal-insulator-semiconductor) structure was determined comprising porous anodic alumina as the insulator and semiconductive TaxOy on the top of the insulator. The electric conductivity of the MIS structures was studied by using amper-volt IV and CV characteristics. The results of the cyclic voltametry, impedance spectroscopy and chronoamperometry are discussed.
|
113 |
Comprendre l’évolution de la cryosphère et du climat du Pliocène à la transition Plio-Pléistocène / Understanding the cryosphere and climate evolution from Pliocene to Plio-Pleistocene transitionTan, Ning 25 April 2018 (has links)
Cette thèse est consacrée à l’étude de l’interaction cryosphère-climat depuis le milieu du Pliocène jusqu’au quaternaire pendant l’installation pérenne de la calotte groenlandaise. Nous étudions d’abord les causes du développement et de la disparition de l’importante mais courte glaciation qui a eu lieu pendant le stade isotopique marin M2 (MIS M23.264-¬3.312 Ma). Ensuite, dans le cadre du programme international sur la modélisation du Pliocène (PLIOMIP2), nous étudions le climat de la période chaude du Plaisancien moyen(MPWP, 3.3-3.0Ma). Enfin, la troisième période étudiée est la transition Plio-Pléistocène transition (PPT, 3.0-2.5Ma), que nous avons étudiée grâce à un couplage asynchrone entre un modèle de climat et un modèle de calotte. A travers ces différentes périodes, nous avons amélioré la connaissance des relations entrepCO2, tectonique et climat pendant la transition d’un monde chaud et riche en CO2 vers le monde bien plus froid et à faible pCO2 des glaciations quaternaires. Ce résultat montre l’importance de mieux comprendre les relations entre dynamique océanique, pCO2 et climat. / This thesis is devoted tounderstanding the interaction betweencryosphere and climate from the mid Plioceneto the early Quaternary during the onset ofNorthern Hemisphere Glaciation (NHG).Firstly, we investigate the causes for thedevelopment and decay of the large but shortliving glaciation that occurred during MarineIsotope Stage 2 (M2, 3.264-¬3.312 Ma);Secondly, in the framework of the internationalPliocene Model Intercomparison Project(PLIOMIP2), we study the climate of Mid-Piacenzian Warm Period (MPWP, 3.3-3.0Ma).Thirdly, we explore the Plio-PleistoceneTransition (PPT, 3.0-2.5Ma) with anappropriate asynchronously coupled climatecryosphere model. Through these differentperiods, we provide a better understanding ofthe relationship between pCO2, tectonics andclimat during the transition from a warm andhigh-CO2 world to the cold and low-CO2Quaternary glaciations. This work also pointsout the necessity to further study the linkbetween ocean dynamics, carbon cycle andclimate.
|
114 |
Neobvyklé tumory kůže a měkkých tkání / Unusual tumors of the skin and soft tissueHadravský, Ladislav January 2016 (has links)
This doctoral thesis describes unusual skin and soft-tissue tumors, which were the basis of the postgraduate study of Ladislav Hadravský, MD at Medical faculty in Pilsen of Charles University in Prague during 2013 - 2016. It contains documented cases of skin and soft-tissue tumors related to hereditary syndromes, unusual morphology, rare biological behavior, minor causal association with the respective disease, or different phenotypes. These cases were published in journals with the impact factor and in peer-reviewed journals. Regarding skin tumors, the study focused on sebaceous tumors of the skin, which may occur within Muir-Torre syndrome. In the retrospective study of sebaceous skin tumors, two unusual cases were found: the case of aggressive extraocular sebaceous carcinoma on the scalp in a patient with Muir-Torre syndrome and the case of multiple sebaceous skin tumors in a patient with MUTYH-associated polyposis of the colon mimicking Muir-Torre syndrome. As far as soft-tissue tumors are concerned, the study aimed at the morphological comparison of cases of myxoinflammatory fibroblastic sarcoma and pleomorhic hyalinizing angiectatic tumor.
|
115 |
SARS-CoV-2 variants and the risk of pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 among children in GermanySorg, A. L., Schönfeld, V., Siedler, A., Hufnagel, M., Doenhardt, M., Diffloth, Natalie, Berner, Reinhard, Kries, R. v., Armann, J. 08 April 2024 (has links)
Purpose
To investigate the relationship between the risk of pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) in children and the predominance of different SARS-CoV-2 variants of concern (VOC) over time.
Methods
In relation to the Alpha, Delta, and Omicron VOC phases of the pandemic, the risk of developing PIMS-TS was calculated by analyzing data for rtPCR-confirmed SARS-CoV-2 infections reported to the German statutory notification system, along with data captured by a separate, national PIMS-TS registry. Both overall infection rates and age group-specific ratios of PIMS-TS during the different pandemic phases were calculated using the Alpha period as the baseline.
Results
The PIMS-TS rate changed significantly over time. When the Alpha VOC was dominant [calendar week (CW) 11 in March–CW 31 in August 2021], the PIMS-TS rate was 6.19 [95% confidence intervals (95% CI) 5.17, 7.20]. When Delta prevailed (CW 32 in August 2021–CW 4 in January 2022), the rate decreased to 1.68 (95% CI 1.49, 1.87). During the Omicron phase (CW 5 in January–CW 16 in April 2022), the rate fell further to 0.89 (95% CI 0.79, 1.00). These changes correspond to a decreased PIMS-TS rate of 73% (rate ratio 0.271, 95% CI 0.222; 0.332) and 86% (rate ratio 0.048, 95% CI 0.037; 0.062), respectively, in comparison to the Alpha period. Rate ratios were nearly identical for all age groups.
Conclusion
The data strongly suggest an association between the risk for PIMS-TS and the prevailing VOC, with highest risk related to Alpha and the lowest to Omicron. Given the uniformity of the decreased risk across age groups, vaccination against SARS-CoV-2 does not appear to have a significant impact on the risk of children developing PIMS-TS.
|
116 |
THE EFFECT OF A NAVIGATIONAL AID ON TRAINING OF A MINIMALLY INVASIVE SURGERY CAMERA TASKVidwans, Ketan 30 July 2012 (has links)
Minimally Invasive Surgery (MIS) differs from Open Surgery as surgeons view the surgical site indirectly on a monitor. The view shown is typically from an angled endoscope off to one side of the surgery (i.e., uncollocated with the view of the hands). This makes camera navigation a challenging ability to learn. MIS thus requires longer training periods, more practice and mental effort to achieve proficiency. Current training setups and Operating Room (OR) environments lack appropriate real-time visual cues for navigation and other perception related information that could help with learning and performance in the OR. The purpose of this research was to design and develop graphical aids for improving understanding of camera navigation and depth perception in a trainer box necessary for enhancing surgeon’s skills to perform endoscopic surgery. For the former, two alternate training methods: 1) using no graphics (control group) and 2) using three different types of graphics conveying different information, were considered for this study. The effectiveness of the training was evaluated by a comparative analysis of different performance measures across all the groups. It was observed that training using graphics did improve the performance of participants in performing a minimally invasive surgery training task. For the latter, the use of a proximity sensor was explored.
|
117 |
EXAMINATION OF THE EFFECT OF DIFFERENT TRAINING METRICS ON PERFORMANCE OF A MINIMALLY INVASIVE SURGERY TRANSFER TASKMadera, Cristofer 10 December 2013 (has links)
The purpose of this experiment was to determine if there existed techniques to more efficiently train prospective surgeons the skills necessary to capably perform minimally invasive surgical procedures. Also, we wanted to know if trainees could be pushed to cognitively define a laparoscopic environment with a novel hand-eye relationship. To explore these questions, a simulation was setup wherein subjects would perform a laparoscopic transfer task and receive active feedback during training. Different subjects would receive different metrics as feedback and a comparison would be made between subjects with respect to standard metrics. Results of this experiment show that all subjects adapt to a laparoscopic environment and that they do so at different rates and to different proficiencies. The difference was shown to be statistically significant. It was concluded that the techniques we utilized were effective enough to claim as useful techniques to utilize in current training systems.
|
118 |
RemnantsJones, Angel D., Mrs. 01 January 2015 (has links)
Angel Jones
Artist Statement
My mixed media collages address issues concerning the outcast, the overlooked, and the underprivileged. My inspirations come from what I experience and perceive around me. My purpose in life is to use my art to address social issues that involve children. For example, I focus my attention on issues ranging from homelessness to mental illness. I am passionate about how vital these concerns are to our success as human beings.
To express my ideas, I layer a variety of materials and textiles. The materials include fragments of photographs, drawings, and objects. The textiles include articles of clothing and fabrics. Recurring symbols and imagery link the individual pieces together. The theme of each work determines the materials and media. While doing research for a piece, new social issues often surface and lead to the next piece.
|
119 |
Properties and evolution of dense structures in the interstellar medium / Propriétés et évolution des structures denses en milieu interstellaireParikka, Anna 28 September 2015 (has links)
Mon travail de thèse présente deux types de structures denses : des sources froides compactes détectées par Planck et des condensations denses dans une région de photodissociation (PDR), à savoir la Barre d’Orion. Les deux types de structures sont étroitement liées à la formation des étoiles. Les sources froides sont étudiées comme objets potentiellement gravitationnellement liés, c’est-à-dire comme objets préstellaires. La Barre d’Orion est intéressante en tant que PDR à fort champ UV (G0 ∼104) prototypique, avec plusieurs disques protoplanétaires connus, éclairés par les jeunes étoiles du Trapèze.D’abord, je présente un article publié dans A&A: The Physical state of selected cold clumps. Dans cet article, nous avons comparé les observations du continuum de la poussière par Herschel provenant de l’open time key program Galactic Cold Cores (Herschel) aux observations de raies moléculaires par le radiotélescope de 20-m de l’Onsala Space Observatory en Suède. Les objets ont été sélectionnés en fonction de leur luminosités et faibles températures de couleur des poussières (T∼10−15 K). Nous avons calculé les masses du viriel et de Bonnor-Ebert et les avons comparées aux masses déduites à partir des observations. Les résultats indiquent que la plupart des objets froids observés ne sont pas nécessairement préstellaires.Dans mon étude de la Barre d’Orion, j’utilise des observations de l’instrumentPACS d’Herschel du programme Unveiling the origin and excitation mechanisms of the warm CO, OH and CH+ . Je présente des cartes de 110” ×110” du cation méthylidyne (CH+ J=3-2), des doublets de OH à 84 μm, et des raies de CO á hauts J (J=19-18). C’est la première fois que ces traceurs des PDR ont présentés avec une telle résolution spatiale et un tel rapport signal-sur-bruit.La répartition spatiale de CH+ et OH montre la même structure de la Barre qui a été vue dans d’autres observations. La morphologie du CH+ et H2 confirme que la formation et l’excitation de CH+ est fortement dépendante du H2 excité vibrationnellement. Le maximum d’émission de OH84 μm correspond à un objet brillant jeune, identifié comme le disque protoplanetaire 244-440.Je présente également des transitions rotationnelles de CO de moyenne (∼20 K) et haute (∼1000 K) énergie. La morphologie de l’émission du CO rotationnellement excité est corrélée avec la présence des petites structures denses irradiées. Nous établissons le lien entre le coeur de ces structures, tracé en CS J=2-1 par Lee et al. (2013) et H 13 CN par Lis and Schilke (2003) et le bord de la PDR, tracé en CO J=19-18 et le H 2 vibrationnellement excitée. Nous montrons également que le CO est principalement excité par le chauffage UV. / In this thesis I present a study of two kinds of dense ISM structures: compact cold sources detected by Planck and dense condensations in a photodissociation region (PDR), namely the Orion Bar detected by ground-based and Herschel telescopes. Both kinds of structures are closely related to star formation. The cold sources are investigated as potentially gravitationally bound, prestellar, objects. The Orion Bar is a highly FUV-illuminated (G0=104) prototypical PDR, with several known protoplanetary disks, illuminated by the young Trapezium stars.First I introduce a paper published in A&A: The Physical state of selected cold clumps. In this paper we compared the Herschel dust continuum observations from the open time key program Galactic Cold Cores to ground based molecular line observations from the 20-m radio telescope of the Onsala Space Observatory in Sweden. The clumps were selected based on their brightness and low dust color temperatures (T=10-15 K). We calculated the virial and Bonnor-Ebert masses and compared them to the masses calculated from the observations. The results indicate that most of the observed cold clumps are not necessarily prestellar.Then I move on to the warm and dense condensations of the ISM. In my study of the Orion Bar, I use observations from PACS instrument on board Herschel from the open time program Unveiling the origin and excitation mechanisms of the warm CO, OH and CH+. I present maps of 110”x110” of the methylidyne cation (CH+ J=3-2), OH doublets at 84 µm, and high-J CO (J=19-18). This is the first time that these PDR tracers are presented in such a high spatial resolution and high signal-to-noise ratio. The CH+ and OH have critical densities (1010 cm-3) and upper level energy temperatures (250 K). In addition the endothermicity of the CH+ + H2 reaction (4300 K) that forms CH+ is comparable to the activation barrier of the O + H2 reaction (4800 K) forming OH. Given these similarities it is interesting to compare their emission. The spatial distribution of CH+ and OH shows the same clumpy structure of the Bar that has been seen in other observations. The morphology of CH+ and H2 confirms that CH+ formation and excitation is strongly dependent on the vibrationally excited H2, while OH is not. The peak in the OH 84 µm emission corresponds to a bright young object, identified as the externally illuminated protoplanetary disk 244-440.Finally, I study the high-J CO in the Orion Bar. I also introduce low- and mid-J CO observations of the area. The high-J CO morphology shows a clumpy structure in the Bar and we establish a link between the dense core of the clumps, traced in CS J=2-1 by Lee et al. (2013) and in H13CN by Lis and Schilke (2003). We also show that the high-J CO is mainly excited by the UV heating.
|
120 |
Client Information Needs of MFIs : A Case Study of ASA BangladeshAhmed, Juber January 2010 (has links)
Abstract Title: Client Information Needs of MFIs: A Case Study of ASA Bangladesh Author: Juber Ahmed Academic Advisor: Dr. Klaus Solberg Søilen Department: School of Management, Blekinge Institute of Technology Course: Master Thesis in Business Administration Purpose: To enrich the knowledge base of client’s needs of financial services and assessing the tools MFIs used to collect clients’ information and how they utilized the information for developing new products and services or modifying existing products and services or their terms and conditions to meet the needs of financial services of their clientele. Also how MFIs organized and managed the information and how they categorized their clients using that information. Method: The investigation conducted from both a theoretical and an empirical point of view. The deductive approach used for the study and the case study method deployed. I studied ASA which is an MFI renowned in Bangladesh and beyond. At first, I had gone through a secondary research for collecting a number of successful methods and standard types of information used by successful MFIs from existing literature. In primary research, I interviewed 10 Managers (Assistant Directors) for ASA to determine which of the methods found in the literature were more effective for collecting clients’ information for them and also asked them to add their ideas to the list. At last I asked interviewees to rate the methods and results presented in this paper. Theory: This study was an exploratory one where I discussed the related aspects for the study - Microfinance, Client Assessment, Clients of Microfinance, Information needs and Management Information System. Findings: The study showed that ASA utilized client information for developing their credit products and services and based on number of loans taken by the clients they categorized their clients and modified or developed new products and services for each category of clients. Although ASA executed several tools for collecting client information but the managers think that their staffs’ collection of information from regular meeting with clients was more effective than others for modifying products’ terms and conditions and modifying or developing new products and services to their women and small enterprise clients. The conducted study also revealed that in ASA impact study was necessary to know clients’ overall level of satisfaction but management needed specific information on what aspects of ASA and its credit products and services clients preferred and did not prefer and the reasons of the preferences. Also they needed action plan to address clients’ specific concerns, so they needed the information on a continual basis and they were successful to achieve this continuous flow of information. For ASA, the best way to get this type of information would be through client satisfaction Focus Group Discussions (FGDs), although they utilized several tools but not often as discussed in part 3 in chapter 5. ASA owned an MIS (AMMS) for monitoring and managing clients’ information and they utilized this to categorize their clients based on the collected information about their number of loans. Conclusion: This study revealed that ASA served only women and small enterprise clientele that included the vulnerable non-poor and could contribute to the profitability of ASA. There was no attempt to diversify the products to include all poor that should be the goal of microfinance to alleviate poverty. Moreover client treated as individual client but the loans used to fulfill household or family needs of the clients. There were tools for collecting information on household about impact of credit programs participation but they took seldom effort for collecting information of the household money management or in other words how they utilized the loans for variety of household needs. There is lack of access to a variety of financial services for poor clients, even though MFIs are mostly serving vulnerable non-poor instead of taking consideration of all categories of poor. It revealed from the study that MFIs could gain long term success by serving specific market segment but it should not be only focus of MFIs, their initiative should be to include all poor in their clients profile with a priority to a specific market segment. This could help them to become sustainable and to minimize risks by spreading it in different market segments. The study found that ASA considered FGDs as an effective tool for collecting clients’ information as their staffs and managers were familiar with this tool, moreover it was cost effective for them. It observed that they seldom followed Tool Selection Process and it was the top management that decided over the tools, the decision might influence by internal and external interest groups and the competition. MFIs should organize client information in a way so that they could be able to manipulate the specific client information to serve client better and to take effective decision, although it is imperative to argue that they may like to serve the wealthier clients. This research paper is also presenting some important findings from existing literature of microfinance and a number of recommendations based on the study experience and scholars opinions from existing microfinance study that may help MFIs to prepare themselves to adopt client-oriented approach by utilizing client assessment tools to fulfill the needs of financial services of their clients that may hopefully include all poor irrespective of their categories.
|
Page generated in 0.0313 seconds