• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 186
  • 79
  • 77
  • 28
  • 23
  • 11
  • 9
  • 6
  • 6
  • 6
  • 5
  • 5
  • 3
  • 3
  • 2
  • Tagged with
  • 505
  • 285
  • 79
  • 65
  • 50
  • 50
  • 43
  • 43
  • 42
  • 41
  • 35
  • 30
  • 29
  • 28
  • 27
  • 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.
1

Push toy : Development of a toy with movement devices associated to the wheels

Alonso García, María, Serrano Gallego, Sara January 2010 (has links)
This is s Bachelor Degree Project report based on the design of a push toy in collaboration with Playsam. The new design consists of a wooden spacecraft. The toy can be described as a safe toy appropriated for kids within a range of ages between 1 and 3 years old.  The attractive design of the toy will help the children to increase their imagination. It is a dynamic product that, firstly, seems not to be more than a spacecraft with two wheels that needs another foothold to keep staying up. On the other hand, when the kids take it, they will observe that the product can be displaced by the wheels, and they will find an attractive rotational motion that combines two complementary colours. The requirements stated by the company were achieved: -       Firstly, the toy must move one of its parts being it connected to the wheels. The product has two main parts. One of them will rotate regarding to the other one when the child drags it thanks to a designed gear system. -       Secondly, the toy would be made of wood as well as all the company products. The elected wood was beech wood, getting a similar appearance to the Playsam products aesthetic. -       The last requisite of the company was to make the toy easy to handle and manipulate. The anthropometric study organized by the design team guarantees it.  The mediums of the data were considered to build the toy.  It was considered that children less than 18 months will take it by the holes and not the surface. The design team bore the European directive 88/378/EEC for Safety of Toys in mind. It was essential to guarantee the safety of the child.
2

The design and implementation of push pull converter

Chan, Yong-bin 05 September 2008 (has links)
Converter devided into linear converter and switching-mode cinverter. push pull has large hystersis loop,so that it supples large power compared with forward topology.it has another adventage ,is easy to drive than half-bridge or full-bridge .the main purpose of the thesis is to study and design push pull converter . First, it is detail to analysis push pull converter's theorem.afterward the push pull converter is described including the component and circuit design .finally push pull converter is implemented and demonstrated
3

Push toy : Development of a toy with movement devices associated to the wheels

Alonso García, María, Serrano Gallego, Sara January 2010 (has links)
<p>This is s Bachelor Degree Project report based on the design of a push toy in collaboration with Playsam. The new design consists of a wooden spacecraft.</p><p>The toy can be described as a safe toy appropriated for kids within a range of ages between 1 and 3 years old.  The attractive design of the toy will help the children to increase their imagination. It is a dynamic product that, firstly, seems not to be more than a spacecraft with two wheels that needs another foothold to keep staying up. On the other hand, when the kids take it, they will observe that the product can be displaced by the wheels, and they will find an attractive rotational motion that combines two complementary colours.</p><p>The requirements stated by the company were achieved:</p><p>-       Firstly, the toy must move one of its parts being it connected to the wheels. The product has two main parts. One of them will rotate regarding to the other one when the child drags it thanks to a designed gear system.</p><p>-       Secondly, the toy would be made of wood as well as all the company products. The elected wood was beech wood, getting a similar appearance to the Playsam products aesthetic.</p><p>-       The last requisite of the company was to make the toy easy to handle and manipulate. The anthropometric study organized by the design team guarantees it.  The mediums of the data were considered to build the toy.  It was considered that children less than 18 months will take it by the holes and not the surface.</p><p>The design team bore the European directive 88/378/EEC for Safety of Toys in mind. It was essential to guarantee the safety of the child.</p>
4

Photocycloadditionen captodativer Olefine an Indole, Benzo(b)thiophene und -furane

Bauschlicher, Tanja. January 2002 (has links) (PDF)
Duisburg, University, Diss., 2002.
5

Polymères push-pull sur la base de platine ( II ) complexes ou porphyrinzinc ( II ) et des dérivés quinoniques : synthèse et étude photophysique

Wang, Xiaorong January 2015 (has links)
Résumé : Au cours des dernières décennies, la conception de nouveaux polymères «push-pull» a été le sujet d'intenses recherches pour les cellules photovoltaïques. Cette thèse de doctorat comprend deux sujets principaux de recherche, l'une est la synthèse et la caractérisation de polymères organométalliques contenant l’unité trans-bis(éthynyl)bis(tributylphosphine)platine(II) comme l’un de deux blocs de construction et des dérivés quinoniques et anthraquinoniques agissant respectivement comme donneur et accepteur de densité électronique, et ainsi que des composés modèles correspondants pour fins de comparaison. L’autre sujet traite des polymères contenant l’unité zinc(II)porphyrine (donneur) et les mêmes dérivés quinoniques et anthraquinoniques. Habituellement les polymères «push-pull» conjugués sont tout d'abord étudiés car ils peuvent montrer de nouvelles bandes d’absorption dites bandes de transfert de charge vers le rouge du spectre solaire, démontrant ainsi l’existence de communication électronique à travers la chaine du polymère, mais aussi permettant de collecter plus de photons par le matériau. Ce travail est divisé en quatre chapitres. / Abstract : In recent decades, the design of new « push-pull » polymers has been the subject of intense research for photovoltaic cell applications. This thesis deals with two main subjects, one is the synthesis and characterization of organometallic trans-bis(ethynyl)bis(tributylphosphine)platinum(II), ([Pt]) and quinone or anthraquinone derivatives-based polymers. Some model compounds have been produced as well for comparison purposes. Another issue is the synthesis and characterization of polymers built upon zinc(II)porphyrin units and the same quinone and anthraquinone derivatives respectively acting as donor and acceptor of electronic density. Such «push-pull» polymers are used to be investigated because of their so-called charge transfer absorption bands in the red part of the solar spectrum. This phenomenon is due to the electronic communication over the whole chain. This new band allows the material to collect more photons. The whole work is divided into four chapters.
6

Ab Initio Study of the Rotation around the Carbon-Carbon Double Bond in Push-Pull Systems

Rattananakin, Pornpun 13 May 2006 (has links)
A series of push-pull systems with different electron donors and electron acceptors were investigated. The carbon-carbon double bond rotational barriers for twelve push-pull ethylene derivatives, NH2CH=CHX, NH2H=CHX and -OCH=CHX (acceptors, X = BH2, CN, NO2, and +CH2) were studied by ab initio calculations. The rotational barrier was chosen as a probe for push-pull effects, as push-pull effects would remove electrons from the central double bond. Complete geometry optimizations and calculations of vibrational frequencies were performed for all minima and transition state structures of the twelve systems. The Synchronous Transit-Guided Quasi-Newton (STQN) method was used to search for the transition state structures. The calculations were carried out at B3LYP/6-31++G(d,p) and MP2/6-311++G(d,p) levels of theory. Electron density maps were used to analyze the electron density distribution. The Merz-Singh-Kollman scheme was chosen to calculate electrostatic potential derived charges on atoms. Calculations at the MP2 level suggest that the strongest push-pull effects result from +CH2 with barriers (to conversion to the transorms) of 10.6, 13.2, and 7.3 kcal/mol for NH2CH=CHCH2+, NH2H=CHCH2+, and -OCH=CHCH2+, respectively. These barriers are about 6, 5, and 9 times smaller than that of ethylene at the same level of theory, respectively. Among the other electron acceptors studied, BH2 was stronger than the cyano and nitro substituents but weaker than CH2+. Solvent effects were examined for the NH2CH=CHX system, X = BH2, CN, NO2, and +CH2 with water and dichloromethane as solvents. Calculations were performed at the B3LYP/6-31++G(d,p) level of theory using three different approaches, the Conductor-like Screening Model (COSMO), the Polarizable Continuum Model (PCM) and the Super-Molecular Approach (SMA). When the solvent is water, SMA calculations retained the barrier-height order of gas phase calculations, while COSMO and PCM reversed the order of BH2 and NO2. Results from this research confirm that both solvents lowered the rotational barriers in all cases. The more polar solvent decreases the rotational barrier more than the less polar solvent due to the existing of a dipolar or charge separated transition states of the push-pull systems.
7

Metoder för att sända meddelanden från QT Systems fastighetssystem till smarta telefoner / Methods for sending messages from QT Systems' real estate system to smartphones

Jernberg, Johan January 2016 (has links)
Företag har länge kunnat nå ut med information till kunder via traditionella metoder så som sms och e-post. I och med den stora populariteten hos smarta telefoner och sociala medier har information nu blivit extra viktigt. Med detta har det även kommit nyare sätt för företag att kommunicera med sina kunder så som via push-notifikationer till smarta telefoner och webbläsare eller via sociala medier. Projektet beställdes av QT Systems och hade som syfte att ge företaget en bättre inblick i vad de har för möjligheter när det gäller att nå ut med information till deras kunder. Målet med projektet var att finna den metod som bör passa bäst för att just QT Systems fastighetssystem ska kunna notifiera deras användare om olika händelser och att kunna visa att denna går att implementera i detta system. Under arbetets gång bestämdes det att push-notifikationer till en native app skulle vara den bästa lösningen. Det har även gjorts ett ”proof-of-concept” som visar att den valda metoden kommer gå att implementera i QT Systems fastighetssystem och åtminstone nå ut till smarta telefoner som har Android eller iOS som operativsystem. / For a long time companies have been able to reach out to customers by traditionally methods such as SMS or e-mail. The huge rise of popularity in smartphones and social media now makes information more important than ever. With this there are newer ways for companies to communicate with their customers such as push-notifications by native apps and browsers or by social media. This project was ordered by QT Systems with the purpose to give the company a better view of their possibilities when it comes to reaching out with information to their customers. The goal with the project was to find the best method for allowing QT Systems' real estate system to notify their users of certain events and to show that this method can be implemented in this system. During the course of this project it was decided that push-notifications by a native app would be the best solution. A ”proof-of-concept” which shows that this method can be implemented in QT Systems' real estate system and that it can be used for at least Android and iOS smartphones was also done.
8

Architecture for Web Server with Push Capability

Tsai, Ching-Shin 20 July 2001 (has links)
none
9

Analýza motivace a postojů k založení vlastního podnikání na základě push-pull teorie / Analysis of Employee Motivation and Their Attitudes to Establishing Their Own Business Based on Push-pull Theory

Čibenková, Kateřina January 2018 (has links)
The topic of thesis is motivation of experienced employees toward to starting own business. The purpose is to identify the attitudes of respondents to leave their job and decide to start own business within push-pull theory. Research is carried out on the basis of questionnaire which is divided into three parts. Results of thesis will be suggestions for companies to reduce workers leaving the job depending on push factors.
10

Konsumenternas attityd till reklam på Snapchat / The consumers attitude towards advertising on Snapchat

Ekhamn, Jonathan, Tillack, Emelie January 2016 (has links)
Titel: Konsumenternas attityd till reklam på Snapchat Nivå: Kandidatuppsats inom företagsekonomi med inriktning på internationell marknadsföring (15 HP), VT-2016. Författare: Emelie Tillack &amp; Jonathan Ekhamn Handledare: Navid Ghannad Examinator: Hélène Laurell Syfte: Syftet med den här studien är att skapa en ökad kunskap ochförståelse kring konsumenternas attityd till reklam på Snapchat. Metod: Denna uppsats utgår från ett deduktivt förfaringssätt. Detta kombinerat med både en kvantitativ och en kvalitativ ansats harutmynnat i en enkätundersökning samt åtta djupintervjuer med respondenter som är aktiva på Snapchat. Teoretiskt Ramverk: Detta kapitel behandlar teorier om vad en attityd är, en attitydmodell, attityder på sociala medier, integritet samt push och pullmarknadsföring. Empiri: Kapitlet redogör för den empiri som samlats in genom vår enkätundersökning och de åtta djupintervjuerna. Slutsats: Undersökningen visar att konsumenternas attityd till reklam på Snapchat är positiv. Anledningen till detta är att reklamen på Snapchat är frivillig. Genom underhållande och trovärdig reklam ökar konsumenternas positiva attityd. Nyckelord: Snapchat, Attityd, Push &amp; Pull, Integritet, Sociala medier, Reklam

Page generated in 0.0295 seconds