33 research outputs found
Modulated electron-multiplied fluorescence lifetime imaging microscope: All-solid-state camera for fluorescence lifetime imaging
No full textWe have built an all-solid-state camera that is directly modulated at the pixel level for frequency-domain fluorescence lifetime imaging microscopy (FLIM) measurements. This novel camera eliminates the need for an image intensifier through the use of an application-specific charge coupled device design in a frequency-domain FLIM system. The first stage of evaluation for the camera has been carried out. Camera characteristics such as noise distribution, dark current influence, camera gain, sampling density, sensitivity, linearity of photometric response, and optical transfer function have been studied through experiments. We are able to do lifetime measurement using our modulated, electron-multiplied fluorescence lifetime imaging microscope (MEM-FLIM) camera for various objects, e.g., fluorescein solution, fixed green fluorescent protein (GFP) cells, and GFP-actin stained live cells. A detailed comparison of a conventional microchannel plate (MCP)-based FLIM system and the MEM-FLIM system is presented. The MEM-FLIM camera shows higher resolution and a better image quality. The MEM-FLIM camera provides a new opportunity for performing frequency-domain FLIM.Image Science and TechnologyApplied Science
Comfort
No full textStreven naar comfort of het tegengaan van gebrek aan comfort (discomfort) kan de samenleving veel geld schelen. Comfort is geen luxe. Het is riskant te vertrouwen op ontwerpen die worden aangeboden onder het motto van comfort. Ontwerpers en ergonomen kunnen een unieke aanpak bieden waarin aangetoond wordt hoeveel mensen het product comfortabel zullen vinden. Spreker pleit voor meer kennis aangaande discomfort toe te passen in participatief ergonomische ontwerptrajecten. Ook is nieuwe kennis nodig over de relatie tussen beleving en comfort. Dit kan aan de hand van experimenten waarin vanuit de doelgroep over een zo reëel mogelijke situatie gerapporteerd wordt over comfort
Plasma Etching for Failure Analysis of Integrated Circuit Packages
No full textPlastic integrated circuit packages with copper wire bonds are decapsulated by a Microwave Induced Plasma system. Improvements on microwave coupling of the system are achieved by frequency tuning and antenna modification. Plasmas with a mixture of O2 and CF4 showed a high etching rate around 2 mm3/min. The role of O2 and CF4 in etching molding compound is described. Plastic package with 38 um Cu bond wires and a 2 mm * 3.5 mm die inside is fully decapsulated in 20 minutes. Cu wires remain undamaged after decapsulation proving the efficiency of this method.MicroelectronicsElectrical Engineering, Mathematics and Computer Scienc
Analysis and experimental validation of the figure of merit for piezoelectric energy harvesters
No full textPiezoelectric energy harvesters are at the front of scientific research as enablers of renewable, sustainable energy for autonomous wireless sensor networks. Crucial for this disruptive technology is the achievable output power. Here we show, analytically, that the maximum output energy per unit volume, under a single sinusoidal excitation, is equal to 1/(4 - 2k2) × 1/2dgX2, where k2 is the electromechanical coupling coefficient, d and g are the piezoelectric charge and voltage coefficient, respectively, and X is the applied stress. The expression derived is validated by the experimentally measured output energy for a variety of piezoelectric materials over an unprecedented range of more than five orders of magnitude. As the prefactor 1/(4 - 2k2) varies only between 1/2 and 1/4 the figure of merit for piezoelectric materials for energy harvesters is not k2, as commonly accepted for vibrational harvesters, but dg. The figure of merit does not depend on the compliance, or Young's modulus. Hence we argue that commonly used brittle inorganic piezoelectric ceramics can be replaced by soft, mechanically flexible polymers and composite films, comprising inorganic piezoelectric materials embedded in a polymer matrix.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Novel Aerospace MaterialsStructural Integrity & CompositesEMSD EEMCS Project engineer
Fast Etching of Molding Compound by an Ar/O2/CF4 Plasma and Process Improvements for Semiconductor Package Decapsulation
No full textDecapsulation of a SOT23 semiconductor package with 23 um copper wire bonds is conducted with an especially designed microwave induced plasma system. It is found that a 30%-60% CF4 addition in the O2/CF4 etchant gas results in high molding compound etching rate. Si3N4 overetching which is encountered in plasma decapsulation is solved by an improved etching process. Critical processing parameters are investigated and 350 um thick molding compound on top of the die is removed selectively by pure plasma etching for 6 minutes, which is at least 10 times faster than conventional plasma etchers.MicroelectronicsElectrical Engineering, Mathematics and Computer Scienc
A temperature oscillation instrument to determine pyroelectric properties of materials at low frequencies: Towards elimination of lock-in methods
No full textPyroelectric properties of materials can be accurately determined by applying a new digital signal processing method on the discrete sampled data obtained with a temperature oscillation technique. The pyroelectric coefficient is calculated from the component of the generated current 90? out of phase with respect to the sinusoidal temperature wave. The novelty of the proposed approach lies in the signal analysis procedure which implements a simple Fast Fourier transform that filters residual noise through convolution, and calculates the phase difference between the peaks of the temperature and current waves. The new idea requires relatively simple hardware and enables very accurate measurement of the pyroelectric coefficient of materials at ultra low frequencies, 1–250 mHz, without using costly lock-in amplifiers.Aerospace Structures & MaterialsAerospace Engineerin
Clearing the Road for ISA Implementation? Applying Adaptive Policymaking for the Implementation of Intelligent Speed Adaptation
No full textIntelligente Snelheid Assistent of ISA is de benaming voor een categorie in-vehicle systemen die bestuurder helpen om zich te houden aan de lokale snelheidslimiet (m.a.w. die er voor zorgen dat bestuurder niet te hard rijdt, of er zelfs voor zorgen dat de bestuurder nooit meer te hard kan rijden). De vele (veld) testen die in het verleden gedaan wijzen er allemaal op dat ISA een grote bijdrage zou kunnen leveren aan de verkeersveiligheid. Ondanks het grote potentieel (experts schatten dat een begrenzende ISA in Nederland jaarlijks meer dan 200 doden kan schelen) is ISA tot op de dag van vandaag niet geïmplementeerd. Om beter om te gaan met de onzekerheden die nog spelen rond de implementatie van ISA systemen en om uiteindelijk te komen tot duurzaam beleid met betrekking tot ISA implementatie wordt in het proefschrift een conceptuele aanpak gehanteerd die Adaptive Policymaking (APM) heet. APM is erop gericht om adaptief beleid te maken door vooraf na te denken over de onzekerheden die spelen en de manier waarop het beleid kan falen. Vervolgens wordt het beleid adaptief gemaakt door te bepalen op welke manier er gereageerd moet worden om de uiteindelijke beleidsdoelen te halen (beleid aanpassen, flankerend beleid maken, etc.). In dit proefschrift wordt onderzocht of APM geschikt is voor het ontwerpen van ISA implementatiebeleid voor Nederland. De resultaten laten zien dat ISA klaar is om geïmplementeerd te worden. Beleidsmakers zouden om kunnen gaan met de onzekerheden die spelen door op kleine schaal te beginnen met implementeren en als de tijd verstrijkt geleidelijk het beleid aan te passen aan de nieuwe kennis en omstandigheden (adaptief beleid). APM is een beleidsaanpak die daarbij zou kunnen helpen. De resultaten laten zien dat het ontwerpen van adaptief ISA implementatiebeleid met behulp van APM de kansen vergroot dat het ontworpen beleid, ondanks de onzekerheden die er nog zijn, de vooraf gedefinieerde beleidsdoelen haalt (in het geval van ISA een reductie in het aantal verkeersdoden, gewonden en ongevallen met schade). Desondanks geven de geraadpleegde experts ook aan dat ontwikkelde adaptieve ISA implementatiebeleid hoogstwaarschijnlijk strandt in de besluitvormingsfase (dus dat er geen beslissing over implementatie kan worden genomen). Dit komt omdat het expliciteren van de onzekerheden die nog spelen rondom de implementatie van ISA ertoe zal leiden dat politici helemaal geen beslissing kunnen of durven nemen. ? Intelligent Speed Adaptation (ISA) is an in-vehicle system that supports the driver of a vehicle in complying with the local speed limit (In other words, that helps the driver to comply with the legal speed limit, or make sure the driver cannot drive faster than the speed limit). There is strong evidence that ISA has a great potential when it comes to contributing to traffic safety. However, ISA implementation is being delayed because of many uncertainties. Despite the large potential (it is estimated that a restricting ISA could save up to 200 lives per year in the Netherlands), ISA systems are not implemented yet. This dissertation focuses on the application of a conceptual approach called Adaptive Policy making (APM). APM is designed to develop policies that can be adapted over time, adaptive policies change as the external conditions change. In this dissertation the applicability of APM for ISA implementation in the Netherlands is researched, by operationalizing, applying, and evaluating the APM approach (for the case of ISA). The results show that ISA is ready to be implemented. Policymakers can deal with the uncertainties that still exist by starting to implement ISA on a small scale, and, as time proceeds, gradually adapt the ISA implementation policy to changing conditions. APM is an approach that could support that process. The results also show that designing adaptive ISA implementation policies with APM increases the chance that the policy will be a success, and reaches the predefined goals. (In case of ISA these goals would be: a reduction in the number of accidents, reduction of fatalities due to road accidents, etc.) Despite this experts also indicate that the developed adaptive ISA implementation policy will cause difficulties in the decision making process, and probably results in the fact that decision makers cannot take a decision at all. (It is indicated that making the uncertainties that surround ISA implementation explicit will be counter-productive for the decision making process).Multi Actor SystemsTechnology, Policy and Managemen
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