With the flourishing development of MEMS, it is possible to combine micro-sensors with micro-actuator and apply to the organ transplant in medical fields or as an embedded sensor on buildings or bridges. Generally batteries is are used as the kinetic energy source, but it involves the issue of recycling. Therefore, development of a self-generator utilizing vibrational source from environment is another better choice. This study succeeds in building up the transform mode of electricity in an electro-magnetic vibration-induced micro-generator. The electricity characteristics of micro-generator are obtained by Mathematical software analysis. MEMs technology can be used to fabricate and assemble the microstructure , planar coils and magnetic films. The analytic results of maximum power and minimum volume by using a mathematics model are achieved. The validity of this model is verified by comparing the theoretical and experiment data from the literature.

Récemment, notre laboratoire a identifié un nouveau site commun d'intégration rétrovirale sur le chromosome X chez la souris (S. Landais et al., 2005). Ce site a été associé à un nouveau gène, appelé Kaplan integration site 2 (Kis2), dont l'expression est augmentée dans les cellules tumorales. De façon surprenante, il ne code pour aucune protéine, et produit cinq transcrits d'ARN non codant comportant le précurseur (primiARN) du groupe de six micro-ARN (miARN): miR-106-363 (S. Landais et al., 2007). La compréhension de la fonction des produits de ce gène ainsi que les voies métaboliques dans lesquelles ils sont impliqués pourraient approfondir notre connaissance de la régulation de l'expression des miARN regroupés. L'expression transitoire de ce locus dans des vecteurs d'expression eucaryotes s'est avérée non fructueuse. Afin de contourner cet obstacle, nous avons eu recours à l'infection des cellules par les rétrovirus recombinants contenant le groupe miR-106-363 comme outil permettant l'expression stable du gène d'intérêt. Dans ce travail nous avons établi deux lignées cellulaires, NIH 3T3 (fibroblastes murins) et Ti6 (lymphocytes), qui expriment le gène Kis2 et le groupe miR-106-363 à l'aide de trois constructions rétrovirales. Grâce à la construction pMSCV-Kis2, nous avons surexprimé les miARN du groupe miR-106-363 dans les NIH 3T3 et les Ti6. La construction pLXSN-Kis2 a permis de produire l'un des plus grands transcrits du gène Kis2 (1.7 kb) dans la lignée Ti6. Le test d'indépendance d'ancrage réalisé sur les cellules exprimant le groupe miR-106-363 de façon stable a confirmé son implication dans la transformation maligne et a établi une corrélation entre le niveau d'expression des ces miARN et la gravité de la transformation. L'obtention d'un système d'expression efficace de Kis2/miR-106-363 nous permettra d'étudier plus en détail la fonction de ces miARN, d'identifier leurs cibles et leurs partenaires d'interaction ainsi que d'étudier leur rôle in vivo chez la souris. De plus, les cellules qui expriment le gène de manière stable seront la source infinie du matériel permettant de conduire les expériences à plus grande échelle y compris l'étude des molécules inhibitrices pour le traitement de la leucémie de type T. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : oncogenèse, ARN non codant, miARN, système d'expression rétroviral.

Radiative properties of a material is the core of thermal science and optics, which play critical roles in modern technologies, including microelectronics, energy conversion, and nanotechnology. The key to modify or enhance radiative properties is employing one-, two-, and three-dimensional (1, 2, and 3D) periodic micro/nanostructures. Since their applications are not fully uncovered and very few comprehensive studies are available, the objective of this dissertation is to explore applications of periodic micro/nanostructures with modified radiative properties in modern technologies through both numerically and experimentally investigations. Theses representative applications include the thermal control in rapid thermal processing, the design of a wavelength-selective radiator for thermophotovoltaic systems, and the nanothermal manufacturing. The theoretical foundation of the study is built on the rigorous coupled-wave analysis (RCWA) for numerical calculation of the far-field radiative properties and the electromagnetic field distribution in the near-field regime. Measurements of diffraction efficiencies are conducted on fabricated 1D and 2D periodic silicon microstructures with a laser scatterometer/diffractometer with high angular resolution. The diffraction efficiency can be employed for non-contact surface profile inspection tool because it strongly depends on structure patterns. For better temperature control during rapid thermal processing, the dissertation performs a parametric study on radiation absorption of a generic CMOS device together with its simplified nanoscale structures. The applicability of approximation models, which homogenize micro/nanostructures into a film, is also evaluated. Next, a new concept of complex gratings is proposed for actively tailoring the radiative properties and serving as a thermophotovoltaic (TPV) radiator. The radiator exhibits a wide-band and angle-independent high transverse magnetic wave emittance matching the bandgap of TPV cells so that the energy conversion efficiency can be improved. Furthermore, the nanoscale metallic slit arrays show polarization-dependant enhanced transmission and highly localized electromagnetic energy density, which hold promising potentials in nanothermal manufacturing. Three submicrometer metallic slit arrays are fabricated on top of a silicon substrate. Their spectral transmittance is measured with a Fourier-transform infrared spectrometer and largely agrees with RCWA modeling results. In short, the dissertation clearly demonstrates that precise control and tuning of radiative properties using micro/nanofabrication are not only feasible but also may have numerous technological impacts.

Nowadays, the components are made more and more small, the flow import or exports through the components are required frequently, so a set of micro-channel is need. The main aim of this paper is to study the effect of different inlet pressure and inlet flow velocity of micro-channel. By using the proposed numerical simulation, the pressure, velocity and equivalent stress inside the micro-channel corresponding to different inlet pressure and inlet velocity can be obtained. Also, the life of micro-channel was discussed also. Due to the size effect of the micro-channel, the boundary condition is set as . The error between the simulated and experiment results in less than 15%.

The push toward the miniaturization of electromechanical devices and the resulting need for micro-power generation (milliwatts to watts) with low-weight, long-life devices has led to the recent development of the field of micro-scale combustion. Since batteries have low specific energy (~200 kJ/kg) and liquid hydrocarbon fuels have a very high specific energy (~50000 kJ/kg), a miniaturized power-generating device, even with a relatively inefficient conversion of hydrocarbon fuels to power, would result in increased lifetime and/or reduced weight of an electronic or mechanical system that currently requires batteries for power. Energy conversion from chemical energy to electrical energy without any moving parts can be achieved by a thermophotovoltaic (TPV) system. The TPV system requires a radiation source which is provided by a micro-combustor. Because of the high surface area to volume ratio for micro-combustor, there is high heat loss (proportional to area) compared to heat generation (proportional to volume). Thus the quenching and flammability problems are more critical in a micro-scale combustor. Hence innovative schemes are required to improve the performance of micro-combustion. In the current study, a micro-scale counter flow combustor with heat recirculation is adapted to improve the flame stability in combustion modeled for possible application to a TPV system. The micro-combustor consists of two annular tubes with an inner tube of diameter 3 mm and 30 mm long and an outer tube of 4.2 mm diameter and 30 mm long. The inner tube is supplied with a cold premixed combustible mixture, ignited and burnt. The hot produced gases are then allowed to flow through outer tube which supplies heat to inner tube via convection and conduction. The hot outer tube radiates heat to the TPV system. Methane is selected as the fuel. The model parameters include the following: diameter d , inlet velocity u , equivalence ratio φ and heat recirculation efficiency η between the hot outer flow and cold inner flow. The predicted performance results are as followings: the lean flammability limit increased from 7.69% to 7.86% and the quenching diameter decreased from 1.3 mm to 0.9 mm when heat recirculation was employed. The overall energy conversion efficiency of current configuration is about 2.56.

With the constantly evolving displayer technology, the liquid crystal displayer (LCD) has become widely utilized on the market. As a result, the demand for high-performance LCDs is on the rise. In addition to the color quality and contrast ratio, the brightness of a LCD is also an important issue in LCD applications. Since light source of the LCD depends on the backlight module, it is important to develop efficient a backlight module to improve the brightness of the LCD. The light guide plate (LGP), which makes use of our previously proposed step micro-structure, has two problems. The first is that the thickness limits the dimension of the LGP. The other is that the complex manufacturing process is not suitable for mass-production. Due to these difficulties, we proposed a new design containing periodic trapezoid micro-structures. The periodic micro-structures can be easily fabricated by the ejection-set process. In addition, the dimension of the LGP will not be limited by this new design. In this thesis, we will analyze the performance of our proposed structure and discuss the factors which might affect the output light intensity of the LGP. We made a few dozen prototyping LGPs and measured the output brightness of produced by these periodic micro-structures. The apparent transparent nature of our proposed LGPs is due to the fact that the dimension of the micro-structure is close to the wavelength. Thus the applications of the new LGPs are no longer limited to the LCD backlight modules. It can be also be used for example, as the reading light plate.

Proefschrift Universiteit van Amsterdam. / Met lit.opg. en samenvatting in het Nederlands.

Abstract Smaller companies have less manpower then larger companies to manage administrative tasks. EU has made it possible for member states to reduce the accounting and audit requirements for small companies and Sweden introduced the option of voluntary audit from the fiscal year of 2011 for micro-entities that do not exceed the threshold values of 3 employees, 3 MSEK turnover and 1.5 MSEK balance sheet total. The values are lower than in other countries with voluntary audit. Due to this, previous research on voluntary audit was conducted on larger companies than Swedish micro-entities. The determinant factors for voluntary audit are therefore different in these micro-entities than in SMEs. The purpose of our study is to find what the decision-makers in micro-entities perceive as their reason to retain or dismiss their auditor as it became voluntary.As a starting point, we theorize that some of the relevant factors in previous studies on voluntary audit in SMEs can also have significance for micro-entities. Furthermore, that the relationships between the auditor and client can affect the decision whether to keep the auditor or not, especially as the companies are small enough for the decision-maker to have regular contact with the auditor and the small size of Skellefteå where we conduct the interview study. Our sample is eleven micro-entities in Skellefteå, out of which three have retained their auditor and intend to keep them in the company, four who are registered with an auditor but will not have an auditor next year, three who dismissed their auditor as soon as possible and one who was started after the law came into action and had never had auditor nor accountant. The determining factor for voluntary audit is in all but one case the advice of the auditor or accountant. No other factor was found to have any effect of magnitude.Previous research in the area have found connections between factors such as debt level, firm size, separation of ownership and management, non-audit services, external demand for audited financial statements and net benefits of audit. As the micro-entities in our sample have little or no debt and no separation of ownership and management we found that these factors are irrelevant to the choice of voluntary audit in our sample. Most of the companies perceive these as factors that would be relevant in a larger company, however. It is the largest firms (by turnover) that have kept their auditor, but do not mention this as a determining factor. Almost all companies have non-audit services from the audit firm, which do not seem to affect the voluntary audit decision. Those who had or will dismiss their auditor see no additional benefits by having an auditor than by having an accountant, which is also supported by the fact that only two companies could mention any benefit with audit aside from external demands from the government or tax authority. All companies believe that there are external demands for audited financial statements, but this was not found to be a determining factor.Relationship factors such as trust, interdependence and service quality do not determine the choice for voluntary audit, but do determine if the companies asked the auditor or accountant for advice on retaining or dismissing their auditor. We found that the decision-makers in the micro-entities all asked the professional they have the best and closest relationship with if they should have voluntary audits, and as all auditors replied to continue with the audit whereas all accountants did not consider it as necessary, relationships can definitely be seen as a contributing, but not determining, factor for voluntary audit.

This thesis demonstrates the effect of micro-damage healing on stress and displacement fields in the vicinity of a crack tip in the material that tend to self-heal. The micro-damage healing model is modeled by incorporating time-dependent traction within the crack faces. This time-dependent traction occurs in a small zone referred to as healing process zone. The effect of the micro-damage healing on crack propagation in elastic media is investigated by deriving analytical relations for Stress Intensity Factor (SIF) when micro-damage healing mechanism is in effect. It is shown that the larger values of both healing process zone and bonding strength decrease the value of SIF near the crack tip. In order to clearly capture this phenomenon, a novel technique based on complex variables is used to derive the equations to calculate the stress and displacement fields in elastic media. Using the third correspondence principle, which is suitable in analyzing the crack shortening (healing phenomenon), the corresponding results of stress and displacement fields in elastic media are converted into viscoelastic media. Since asphalt has time-dependent material properties, the viscoelastic result is more accurate than the elastic. It is shown that an increase in the value of both healing process zone and bonding strength results in a decrease in the stress and displacement fields near the crack tip. Finally, the effect of using different coefficients in defining the bonding strength and relaxation time is evaluated. Asphalt concrete pavements are concurrently subjected to mechanical and environmental loading conditions during their service life. Applied mechanical and environmental loadings gradually degrade properties of asphalt concrete pavements. However, under specific conditions, asphalt concrete has the potential to heal and regain part of its strength. Identifying a model for the healing process is crucial. This proposed model is not dependent on the test methods that empower its usage in computational modeling. Moreover, this research considers both effects of instantaneous healing (a result of wetting) and time-dependent bond strength (a result of molecular diffusion between the crack faces), using the complex-variable method. Schapery (1989) considered only instantaneous healing and regarded it as the total bond strength. Therefore, considering both effects of instantaneous and time-dependent bond-strength makes this model superior with respect to the analogous model. It is hoped that this research provides insight on the healing mechanism at micro-scale.

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