Novel Bonding technologies for wafer-level transparent packaging of MOEMS

Depending on the type of Micro-Electro-Mechanical System (MEMS), packaging costs are contributing up to 80% of the total device cost. Each MEMS device category, its function and operational environment will individually dictate the packaging requirement. Due to the lack of standardized testing procedures, the reliability of those MEMS packages sometimes can only be proven by taking into consideration its functionality over lifetime. Innovation with regards to cost reduction and standardization in the field of packaging is therefore of utmost importance to the speed of commercialisation of MEMS devices. Nowadays heavily driven by consumer applications the MEMS device market is forecasted to enjoy a compound annual growth rate (CAGR) above 13%, which is when compared to the IC device market, an outstanding growth rate. Nevertheless this forecasted value can drift upwards or downwards depending on the rate of innovation in the field of packaging. MEMS devices typically require a specific fabrication process where the device wafer is bonded to a second wafer which effectively encapsulates the MEMS structure. This method leaves the device free to move within a vacuum or an inert gas atmosphere.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing

Novel microstructures and technologies applied in chemical analysis techniques

Novel glass and silicon microstructures and their application in chemical analysis are presented. The micro technologies comprise (deep) dry etching, thin layer growth and anodic bonding. With this combination it is possible to create high resolution electrically isolating silicon dioxide structures with aspect ratio's similar to those possible in silicon. Main applications are chemical separation methods such as high performance liquid chromatography (HPLC) or electrophoresis (HPCE). Beside these channel structures, a capillary connector with very low dead and mixing volume has been designed and fabricated for use in (correlation) electrophoresis, and tested by means of precision of consecutive single injection

Electron Transfer Reaction Through an Adsorbed Layer

We consider electron transfer from a redox to an electrode through and adsorbed intermediate. The formalism is developed to cover all regimes of coverage factor, from lone adsorbate to monolayer regime. The randomness in the distribution of adsorbates is handled using coherent potential approximation. We give current-overpotential profile for all coverage regimes. We explictly analyse the low and high coverage regimes by supplementing with DOS profile for adsorbate in both weakly coupled and strongly coupled sector. The prominence of bonding and anti-bonding states in the strongly coupled adsorbates at low coverage gives rise to saddle point behaviour in current-overpotential profile. We were able to recover the marcus inverted region at low coverage and the traditional direct electron transfer behaviour at high coverage

Current developments of nanoscale insight into corrosion protection by passive oxide films

Oxide passive films are a key for the durability of metals and alloys components as well as a central issue in corrosion science and engineering. Herein, we discuss current developments of the nanometer and sub-nanometer scale knowledge of the barrier properties and adsorption properties of passive oxide films brought by recent model experimental and theoretical investigations. The discussed aspects include (i) the chromium enrichment and its homogeneity at the nanoscale in passive films formed on Cr-bearing alloys such as stainless steel, (ii) the corrosion properties of grain boundaries in early intergranular corrosion before penetration and propagation in the grain boundary network, and (iii) the interaction of organic inhibitor molecules with incompletely passivated metallic surfaces. In all three cases, key issues are highlighted and future developments that we consider as most relevant are identified.Comment: Current Opinion in Solid State and Materials Science, Elsevier, final accepted preprin

Unveiling interactions between DNA and cytotoxic 2-arylpiperidinyl-1,4-naphthoquinone derivatives: A combined electrochemical and computational study

Indexación: Scopus.Three 2-arylpiperidinyl-1,4-naphthoquinone derivatives were synthesized and evaluated in vitro to determine their cytotoxicity on cancer and normal cell lines. In order to establish their possible action mechanism, the electrochemical behaviour of these quinones was examined using cyclic voltammetry (CV) as technique by using a three-electrode setup: a glassy carbon, Ag/AgCl (in 3 M KCl), and platinum wire as working, reference, and counter electrodes, respectively. Kinetic studies were done to determine the control of the reduction reaction and the number of transferred electrons in the process. Furthermore, the addition of dsDNA to the quinone solutions allowed for the observation of an interaction between each quinone and dsDNA as the current-peaks became lower in presence of dsDNA. Otherwise, motivated to support the aforementioned results, electronic structure calculations at the TPSS-D3/6-31+G(d,p) level of theory were carried out in order to find the most favourable noncovalently bonded complexes between quinones and DNA. Noncovalent complexes formed between DNA and 2-arylpiperidinyl-1,4-naphthoquinones and stabilized by π-stacking interactions along with the well-known hydrogen-bonded complexes were found, with the former being more stable than the latter. These results suggest that the intercalation of these quinone derivatives in DNA is the most likely action mechanism. © 2018 King Saud Universityhttps://www.sciencedirect.com/science/article/pii/S1878535218300893?via%3Dihu

The Feasibility of a Fully Miniaturized Magneto-Optical Trap for Portable Ultracold Quantum Technology

Experiments using laser cooled atoms and ions show real promise for practical applications in quantum- enhanced metrology, timing, navigation, and sensing as well as exotic roles in quantum computing, networking and simulation. The heart of many of these experiments has been translated to microfabricated platforms known as atom chips whose construction readily lend themselves to integration with larger systems and future mass production. To truly make the jump from laboratory demonstrations to practical, rugged devices, the complex surrounding infrastructure (including vacuum systems, optics, and lasers) also needs to be miniatur- ized and integrated. In this paper we explore the feasibility of applying this approach to the Magneto-Optical Trap; incorporating the vacuum system, atom source and optical geometry into a permanently sealed micro- litre system capable of maintaining $10^{-10}$ mbar for more than 1000 days of operation with passive pumping alone. We demonstrate such an engineering challenge is achievable using recent advances in semiconductor microfabrication techniques and materialsComment: 23 pages, 10 figure

Inhibition Effect of N, N'-Dimethylaminoethanol on the Corrosion of Austenitic Stainless Steel Type 304

The effect of N,N'-dimethylaminoethanol on the corrosion of austenitic stainless steel type 304 in 3M H2SO4 has been studied by weight-loss method and linear polarization measurement in different concentrations of the compound. The inhibition efficiencies of the inhibitor compound on the corrosion of the stainless steel were evaluated through assessment of the anodic and cathodic polarization curves of the alloy, the spontaneity of the electrochemical process, inhibition mechanism and adsorption isotherm. The inhibitor efficiency increased with increase in the inhibitor concentration. Results obtained reveal that the inhibitor performed effectively on the stainless steel providing good protection against pitting and uniform corrosion in the chloride containing acidic solutions. The compound act through physiochemical mechanism on the stainless steel surface and obeyed Langmuir adsorption isotherm. The values of the inhibition efficiency calculated from the two techniques are in reasonably good agreement. Polarization studies showed that the compounds behave as mixed type inhibitor in the aggressive media