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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Integration of a 3.3 kW, AC/DC bidirectional converter using printed circuit board embedding technology / Intégration d'un convertisseur 3.3 kW, AC/DC, bidirectionnel en utilisant la technologie d'enfouissement PCB

Caillaud, Rémy 17 January 2019 (has links)
Les énergies fossiles (Pétrole, Charbon, …) représentent 80 % des énergies consommés. Malheureusement pour l’environnement, elles sont les plus polluantes. Le remplacement actuel des énergies fossiles permet au marché de l’électronique de puissance de grandir d’année en année. L’électronique de puissance permet d’adapter l’énergie électrique à son utilisation finale. Dans la pratique, l’adaptation de l’énergie électrique utilise des convertisseurs. En plus de respecter le volume, l’efficacité et la fiabilité imposés par le cahier des charges pour chaque application, l’électronique de puissance doit aussi permettre de réduire sensiblement les coûts. Le convertisseur doit assurer le fonctionnement électrique du circuit, le support mécanique des composants et la gestion thermique. Le package utilisé par les nouveaux composants à grand gap limite leurs performances. L’intégration des convertisseurs doit développer des méthodes d’interconnexion permettant d’éliminer ce package. L’objectif de la recherche sur l’intégration des convertisseurs est de repousser les limites imposées par un cahier des charges standard tout en assurant ces 3 fonctions principales. Parmi les nombreuses techniques d’intégration, le circuit imprimé (PCB) est mature industriellement, permet la fabrication collective et un assemblage automatisé. L’intégration utilisant le PCB a développé la technique d’enfouissement de puce avec laquelle la puce est directement enfouie dans le PCB sans son package. Cette thèse va étudier la méthode d’enfouissement pour les autres composants nécessaires à la réalisation d’un convertisseur (Condensateurs, Composants Magnétiques). Une optimisation du convertisseur qui doit être réalisé permet de prendre en compte les avantages de cette nouvelle technologie. Un prototype de convertisseur intégré a été réalisé avec des composants utilisant cette technologie. / With the endangering of the environment due to the use of fossil fuels, the power electronics market is growing through the years. The number of applications is increasing in numerous field as, for example, transport (electric car, "more electric" aircraft) or energy (photovoltaic, smart grid). Beyond meeting the volume, efficiency and reliability specifications for each application, power electronics should also reduce substantially costs. Today, the managing of the electric energy uses power electronic converters. The conception of a converter is a multiphysic problem. The converter has to ensure electrical functionality, mechanical support and proper thermal management.The new wide-band gap components are limited in performance by their package. The integration of a converter should use new interconnection methods to avoid the use of packaged components. The trend is to integrate the maximum of components into a single system. This integration can offer benefits such as size and weight reduction, cost saving and reliability improvement by managing the complexity and the high density of interconnection. Among many integration technologies available, Printed Circuit Board (PCB) is well known in the industry, allowing mass production with automated manufacturing and assembly. The PCB integration was developed with the “Die Embedding” technology in which a bare die in embedded directly in the PCB to not use package. This thesis studied the embedding technology on others components necessary to the realization of a converter (Capacitors, Magnetics, …). An optimization of the converter is done taking into account the advantages of this new technology. A prototype of an AC/DC bidirectional converter fully integrated using this technology was realized.
132

Konstrukce dopravníkové nástavby mobilního robotu MiR / Construction of conveyor superstructure of mobile robot MiR

Adámek, Tomáš January 2021 (has links)
The subject of this diploma thesis is the design of a conveyor superstructure of a collaborative mobile robot MiR. The first part is a theoretical research basis focused on mobile collaborative technologies and information related to Mobile industrial Robots. The following is a practical part built on previous acquired knowledge. The key issue of the solution is the logistics transport of the PCB magazine in the field of SMT industry. There are created two structural design variants of the superstructure arrangement for the transport of two binders and the most suitable variant is selected on the basis of the multicriteria basic method. The selected alternative of the conveyor top module is then subjected to design calculations. In order to obtain a comprehensive overview of the prototype production, the following section contains drawing documentation, including relevant comments, an economic cost estimate and a risk analysis.
133

Évaluation des technologies d'impression 3D pour le développement d'antennes directives à large bande passante pour les liaisons backhaul en bandes millimétriques V et E / Evaluation of 3D printing technologies for the development of wide-band directive antennas for millimeter wave backhaul links in E and V frequency bands

Nachabe, Nour 06 December 2018 (has links)
Face à la demande croissante de débits de données de plus en plus élevées, l’une des principales solutions proposées par la 5G est de densifier le réseau en y intégrant notamment de nouvelles « Small cells ». La réorganisation de l’architecture du réseau mobile pour s’adapter à l’intégration poussée de ces Small cells, fait naître la problématique de la connexion backhaul entre les stations de bases desservant les Small cells et le cœur de réseau. Ainsi, des liaisons backhaul de plusieurs Gb/s de données sont nécessaires pour pouvoir assurer un débit de données d’au moins 100Mb/s à l’utilisateur qui est l’un des objectifs fixés pour la 5G. Les solutions de connexion backhaul sans fils ont un avantage indiscutable face aux coûts de déploiements de fibres optiques qui sont très élevés. Pour augmenter la capacité spectrale des liaisons sans fils, l’utilisation des fréquences millimétriques au-delà de 6 GHz caractérisées par des larges bandes passantes sera prochainement discutée pour la 5G durant le World Radiocommunication Conference 2019. Parmi ces fréquences, les bandes V (57-66GHz) et E (71-76 GHz et 81-86 GHz) ont un intérêt indéniable grâce aux larges bandes passantes disponibles ainsi qu’aux conditions de licenciement peu exigeantes. Les travaux développés dans cette thèse consistent à concevoir des antennes directives à large bande passante permettant d’établir les liens backhaul point-à-point sans fils (LoS). En exploitant les technologies de fabrications à faibles coût telles que l’impression 3D et Printed Circuit Board (PCB) sur des substrats FR4, la conception de deux types d’antenne directives a été étudiée à savoir des antennes lentilles et des antennes réseaux. / In order to address the ever-increasing demand of higher data rates, adding small cells to the existing macrocells infrastructure is one of the most important milestones of the 5G roadmap. With the integration of small cells and the re-organization of the network topology, backhaul bottleneck is the main challenge to address in the near future. Facing the costs of deployments of fiber optic connections, point-to-point wireless backhaul links using millimeter wave (mmW) frequencies are gaining prominence. 5G future frequencies, to be discussed under the World Radiocommunication Conference 2019 (WRC-19) open-up the way towards mmW frequency band where large bandwidths are naturally available. The high bandwidths available at these frequencies enable several Gbps data rate backhaul links, which is un utmost necessity to respect the 100 Mbps user-experienced data rate promised by the 5G standard. Millimeter-wave frequencies in V and E-bands unlicensed/light licensed spectrum are considered as primary candidates for backhaul links. In addition to the light license regime, the high free space path loss experienced at these frequencies is rather beneficial to limit the interference between small cells links. Moreover, the high available bandwidths at V and E-bands enable to achieve multi Gb/s links without using complex modulation schemes. In this thesis, we focused our research study on developing high gain wide-band antennas usable in point-to-point backhaul links in a Line of Sight (LoS) context. Leveraging cost-efficient technologies like 3D printing and Printed Circuit Board (PCB) on FR4 substrates, we studied two high-gain antenna types: lens antennas and flat array antennas.
134

Dopplersensor för rörelsedetektering / Motion Detection with Doppler Sensor

Lindberg, Anton, Strid, Mikael January 2015 (has links)
Inom miljöer med krav på hög säkerhet såsom kärnkraftverk behövs ett billigt och pålitligt alternativ för att snabbt och enkelt kunna detektera obehöriga individer vid intrång. Föreliggande rapport beskriver arbetet kring utveckling av en rörelsedetektor som har funktionen att detektera obehöriga personer inom områden där de inte har tillträde. Det slutliga målet med detta arbete är att konstruera en programmerbar krets som arbetar med signalerna från rörelsesensorn HB100, som utan underhåll kan täcka stora ytor. Arbetet har avgränsas till elektronikdesign, filterkonstruktion, EMC samt programmering av den färdiga kretsen. / Within environments with high demands on security like nuclear power plants there is a high demand on a cheap and reliable system for detection of unauthorized individuals of intrusion. This report describes the work on the development of a motion detection system using the doppler effect. The ultimate goal of this work is to design a programmable circuit that works with signals from the motion sensor HB100, which without maintenance can cover large areas. The work has been limited to electronic design, filter design, EMC and programming of the complete circuit.
135

Developing new adsorbents for the passive sampling of organic pollutants in the atmosphere : comparison with existing systems / Développement de nouveaux adsorbants pour l'échantillonnage passifs de polluants organiques dans l'atmosphère : comparaison avec des systèmes existants

Levy, Marine 21 October 2016 (has links)
Les matériaux actuellement utilisés comme capteurs passifs de polluants atmosphériques, la mousse de polyuréthane et la résine XAD®-2, ne sont optimisés ni pour l'adsorption de composés polaires ni pour le captage de particules. Pour remédier à ces limitations, la mousse de carbure de silicium (SiC) est proposée comme alternative. Plusieurs campagnes de mesures ont été mises en place pour comparer SiC et XAD®-2. Les composés recherchés étaient des HAP, des PCB et des pesticides.Une méthode d'analyse combinant ASE, SPE et SPME a été développée et optimisée pour ces polluants. Celle-ci permet d'atteindre de faibles limites de détection et quantification pour les composés recherchés.Les campagnes réalisées montrent que la mousse de SiC est toujours plus efficace que la résine XAD®-2 pour le piégeage de composés particulaires et polaires. De plus, la SiC peut être greffée avec du carbone ou des nanotubes de carbone pour augmenter sa surface spécifique, ce qui la rend également plus performante pour l'adsorption de composés volatils. Les débits d'échantillonnage moyens de la mousse ont été calculés et sont comparable aux valeurs rapportées dans la littérature pour la résine XAD®-2. / Materials currently used as passive samplers for atmospheric pollutants, polyurethane foam and XAD®-2 resin, are not suited ta trapping polar compounds nor particles. Ta overcome these limitations, silicon carbide (SiC) foam is presented as an alternative. Several sampling campaigns monitoring PAH, PCB and pesticides were done ta compare SiC and XAD®-2. An analytical method coupling ASE, SPE and SPME was developed and optimised for these pollutants. lt allowed low limits of detection and quantification ta be reached for all compounds of interest.Sampling campaigns showed that SiC foam is consistently more efficient than XAD®-2 resin at trapping particulate and polar compounds. Moreover, SiC foam can be grafted with carbon or carbon nanotubes ta increase its specific surface area, which also makes it better at adsorbing volatile compounds. Average sampling rates were calculated for SiC foam and they are comparable ta the values reported in the literature for XAD®-2 resin.
136

Undersökning av stabilitet och noggrannhet hos kapacitans baserade fuktgivare i ett varierande klimat

Grufman, Samuel January 2023 (has links)
Studien gick ut på att undersöka och ta fram relativa luftfuktighetsgivare som ger godkända mätvärden mellan [5%, 95%] relativ luftfuktighet med klimatkammare som referens. Med syftet att ersätta företagets givare i deras NDIR koldioxidsensor. Den skulle ersättas då deras nuvarande luftfuktighetsgivare gav felaktiga värden när klimatet gick mot antingen väldigt torrt eller fuktigt. Det är väsentligt att luftfuktighetsgivaren fungerar eftersom företaget använder värdena från givaren för att ge korrekta koldioxidmätningar i deras NDIR sensor. Detta är möjligt eftersom koldioxidhalter har visats sig påverkas av den relativa luftfuktigheten. Givarna införskaffades och monterades på PCB’s. Kod utvecklades för insamling av data genom I2C och SPI kommunikation. Givarna kördes sedan i en klimatkammare som svepte luftfuktigheten mellan [5%, 95%]. Värdena illustrerades i Matlab genom grafer. Givare 2 visade sig ge bäst värden på hela spannet jämfört med resterande givare. Den hade absolut minst avvikelse vid extrempunkterna, samt låg nära referensvärdet vid resterande luftfuktigheter i svepet [5%, 95%]. / The purpose of the study was to examine and bring forth a relative humidity sensor which gives approved values for the span between [5%, 95%] relative humidity with the climate chamber as the reference point. The goal was to replace the companies relative humdity sensor in their NDIR carbon dioxide sensor. It was to be replaced because their current sensor gave incorrect values when the climate was really humid or dry. It’s of value that the sensor gives correct values because the company uses relative humdity readings to correct their carbon dioxide reading in their NDIR sensor. The reason this works is because the carbon dioxide levels has been showed to correlate with the relative humidity. The sensors were studied and bought. They were mounted on top of PCB’s. Code was developed to gather data from I2C and SPI communication. The sensors was then put into an climate chamber and got swept between [5%,95%] relative humidity. The values were illustrated in Matlab through graphs. Sensor 2 proved to give the best values on the entire span [5%, 95%] relative humidity in comparison to the other sensors in the study. It had the least added error of all the sensors at dry/humid climates and was really close to the reference value at the other points of span [5%, 95%] relative humidity.
137

Demontering av ett mekaniskt låssystem med CAN 2.0 : En fallstudie i hur en CAN-buss kan användas inom dörrlåssystem

Hassan, Mahad, Edelsvärd, Fredrik January 2020 (has links)
Låssystem kan minska risken för inbrott och stöld, och vara ett verktyg för behöriga personer att få tillgång till lokaler och rum. Därför är det viktigt att moderna låssystem är pålitliga, öppnar snabbt och är säkra. Detta examensarbete undersöker om CAN (Controller Area Network) är ett idealt kommunikationsprotokoll för ett säkerhetssystem av dörrlås, med syftet att utföra en fallstudie av CAN-protokollet. Detta sker genom att analysera ett låssystem från ASSA vars kommunikationsprotokoll mellan styroch låsenhet misstänktes använda CAN-protokollet mellan dess styrenhet och låsenhet. Slutsatsen av analysen var att låssystemet från ASSA inte kommunicerade via CAN. För att bevisa dettaåterskapades signaler med elektriska standardinterface RS-485. Det sista steget vara att utveckla ett eget låssystem med CAN som kommunikationsprotokoll, och sedan skulle de två låssystem jämföras. För att testa detta programmeras två kretskort av typen ESP32-PoE till en styrenhet och en låsenhet. Ett låssystem designades på ett kopplingsdäck innan den ersattes av två PCBs. Slutresultatet var ett motorlås och en styrenhet som konstruerades och validerades i ett kopplingsdäck. Av de två kretskorten som utvecklades fungerade kontrollenheten som förväntat, medan låsenheten hade problem med dess motor. Den kunde dock klara av dess andra uppgifter som att läsa signaler från styrenheten via en 10 meter kabel och läsa signaler från dess dörrläge givande magnetsensor. Det demonterade låssystemet sänder signaler snabbare, och öppnar låset ungefär lika snabbt, men är inte lika säker som den kommersiella låssystemet för att CAN har restriktiva säkerhetsåtgärder. / Lock systems can reduce the risk of burglary and theft, and be a tool for authorized persons to access premises and rooms. Therefore, it is important that modern lock systems are secure, reliable and open quickly. This thesis investigates whether CAN (Controller Area Network) is an ideal communication protocol for a door lock security system. This is done by analyzing a mechanical lock system from ASSA which was suspected of using CANbus as a communication protocol between the control unit and lock unit. Then the lock and control units were analyzed. The conclusion of the analysis is that the lock system did not communicate via CAN. To prove this, signals were re-created with the electrical standard interface RS-485.The final step was to construct a lock system with CAN as a communication protocol, and then the two lock systems would be compared.To test this, two ESP32-PoE development boards are programmed into a controller and a locking device. A mechanical door lock system was designed on a breadboard before being replaced by two PCBs. Of the two circuit types that were developed, the control unit worked as expected, while the motorlock unit had problems with it’s motor. However, it was able to handle its other tasks such as reading signals from the controller via a 10 meter cable and reading signals from its door locating magnetic sensor. The disassembled lock system sends signals faster, and opens the lock approximately as quickly, but is not as secure as the commercial CAN lock system has restrictive security measures.
138

The Effect of a 2,2',4,4'-Tetrachlorobiphenyl (PCB 47) and 3,3',4,4'-Tetrachlorobiphenyl (PCB 77) Mixture on Enzymes Involved in the Synthesis of Catecholamines in the Rat Adrenal Gland

Pillai, Mahesh R. 07 August 2008 (has links)
No description available.
139

CAN BUS USED FOR DATA ACQUISITION SYSTEM CONTROLS (AUTOMOTIVE SOLUTION FOR AIRCRAFT PROBLEM)

Johnson, Bruce, Smith, John 10 1900 (has links)
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / This paper discusses using the CAN (Control Area Network) Bus protocol for control and status of flight test data acquisition systems. The application of the CAN (Control Area Network) on an F/A-18 aircraft will be discussed in detail.
140

PCB乾燥設備之策略行銷分析 / Strategic Marketing Analysis of pcb dry machine

葉步章, Yeh, Stanley Unknown Date (has links)
印刷電路板PCB(Printed circuit board)為電子產品之載體,截至目前為止尚無可以在市場取代印刷電路板地位之應用出現, 消費性電子產品未來朝向輕薄化發展,例如穿戴式裝置、智慧家庭、物聯網應用等等,汽車也朝向高度電子化發展,各種安全感知以及自動化駕駛需求,車用電子也是未來應用領域,這些新技術發展皆須要使用印刷電路板。 台灣印刷電路板最早始於1969年美商安培公司來台設廠生產,發展至今已有四十多年歷史,由於印刷電路板的製造涵蓋複雜的工藝與流程,因此需要使用許多製程設備,早期設備皆為國外進口,後來因台灣工業技術提升以及精密機械供應鏈日趨完善,在印刷電路板的製程設備,進口設備廠商,逐漸被台灣廠商所取代,其中乾燥製程設備為印刷電路板製作流程不可或缺並難以取代的需求,2000年隨著台灣印刷電路板廠大舉西進移往中國大陸,台灣印刷電路板製程設備製造商隨之擴展版圖,迄今十餘年除了台廠之間的競爭逐漸也面臨到中國當地廠商的競爭。 本研究以策略行銷4C架構來探討印刷電路板乾燥製程設備商個案A公司的現有策略,並以降低外顯單位效益成本、買者資訊搜尋成本、買者道德危機成本、買者專屬陷入成本等交換成本為目標,擬定個案公司A未來的策略。 / Printed circuit board (PCB) as the carrier of electronic products, there is no substitute in the market to replace its position of what the printed circuit board applications can deliver so far. The trend of consumer electronic products tend to be light and thin such as wearable devices, smart home, internet of thing applications and etc. Printed circuit board is also getting widely used in cars as demand driven from development of electronic automation, various security awareness and self-driving needs. The future of automotive electronics applications and the development of these new technologies drive the needs of essential use of printed circuit board. Printed circuit board manufacturing of Taiwan was first built in 1969, American companies- Ampex came to Taiwan to set up production manufactures and has over 40 years of history as of now. Since the manufacturing of printed circuit board requires complex processes and procedures, therefore there is a need of specific equipment where they can only be imported from overseas. Later on as Taiwan's industrial technology has advanced and supply chain of precision machineries have improved, the previously imported process equipment used for manufacturing the printed circuit board are gradually replaced by Taiwanese manufactured ones. Since year of 2000, printed circuit board manufacturing industry has been moved to Mainland China, Taiwan manufacturers are able to extend the production across the region but in a meanwhile they are gradually facing a stronger competition from the Chinese manufacturers in the last 10 years. In this study, we are using 4C architecture of strategic marketing to explore the case of printed circuit board drying process equipment manufacturer – A company existing strategy. In order to develop a strategy for the future of the company, my study is striving to achieve the exchange cost effectiveness, reducing cost of utility, cost of information search, cost of moral hazard and cost of asset specify.

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