Vapor-Phase Self-Assembled Monolayers for Anti-Stiction Applications in MEMS

We have investigated the anti-stiction performance of self-assembled monolayers (SAMs) that were grown in vapor phase from six different organosilane precursors: CF₃(CF₂)₅(CH₂)₂SiCl₃ (FOTS), CF₃(CF₂)₅(CH₂)₂Si(OC₂H₅)₃ (FOTES), CF₃(CF₂)₅(CH₂)₂Si(CH₃)Cl₂ (FOMDS), CF₃(CF₂)₅(CH₂)₂Si(CH₃)₂Cl (FOMMS), CF₃(CF₂)₇(CH₂)₂SiCl₃ (FDTS), and CH₃(CH₂)₁₇(CH₂)₂SiCl₃ (OTS). The SAM coatings that were grown on silicon substrates were characterized with respect to static contact angle, surface energy, roughness, nanoscale adhesive force, nanoscale friction force, and thermal stability. The best overall anti-stiction performance was achieved using FDTS as precursor for the SAM growth, but all coatings show good potential for solving in-use stiction problems in microelectromechanical systems devices.     

Expression of a dominant-negative mutant human insulin receptor in the muscle of transgenic mice

To examine the in vivo effects of a kinase-deficient mutant human insulin receptor, we used the muscle creatine kinase promoter to express a putative dominant-negative receptor: Ala1134-->Thr (Moller, D. E., Yokota, A., White, M. F., Pazianos, A. G., and Flier, J. S. (1990) J. Biol. Chem. 265, 14979-14985) in transgenic mice. Two lines were generated, where receptor expression was restricted to striated muscle and was increased by 5-12-fold in skeletal muscle. Transgenic gluteal muscle insulin receptor kinase activity was reduced by approximately 80% after maximal in vitro insulin stimulation. Glycogen content in this muscle was reduced by 45% in transgenic mice. Insulin levels were approximately 2-fold higher, and glucose concentrations were 12% higher in transgenics fed ad libitum. Transgenic mice exhibited reduced in vivo sensitivity to low dose (0.1 milliunits/g) intravenous insulin. In isolated soleus muscles from transgenics, where mutant receptors were expressed at lower levels, insulin-stimulated receptor kinase activity was reduced by 42%, but insulin-stimulated 2-deoxyglucose uptake was unaffected. These results indicate that (i) overexpression of a kinase-deficient human insulin receptor in muscle causes dominant-negative effects at the level of receptor kinase activation, (ii) impairment of insulin-stimulated muscle receptor tyrosine kinase activity can cause decreased insulin sensitivity in vivo, (iii) kinase-defective receptor mutants may be used to create novel animal models of tissue-specific insulin resistance.     

Condensation Detection Using a Wirelessly Powered RF-Temperature Sensor

The formation of condensation on windshields can be counteracted and even prevented through the concerted use of an automobile heating, ventilation, and air-conditioning (HVAC) system. By anticipating the formation of dew, through the temperature of the windshield and dew point in the cabin, a condensation-free windshield can be ensured. A new approach toward a system for condensation detection is reported. It uses an actively powered humidity sensor, as well as a remotely and wirelessly powered temperature sensor system. The wirelessly powered temperature detector, which may be embedded in the windshield of an automobile, obtains its energy via an inductively coupled magnetic field and simultaneously transmits data through a load-modulation technique. Such a system approach offers advantages in terms of cost, system life, and maintenance, in comparison with existing wired systems and other wireless solutions. The system is implemented using off-the-shelf components and is discretely designed around application-specific resonant tanks. The resonant tanks were mathematically characterized and compared with measured values. The read range of the wirelessly powered condensation detector at a frequency of 13.56 MHz is more than 4 cm while consuming a maximum power of approximately 2 mW. The application of this technology as part of a climate-control system is discussed in this paper. System concept, design considerations, and prototype characterization are also included.     

Short-Wave Infrared HgCdTe Electron Avalanche Photodiodes for Gated Viewing

Short-wave infrared (SWIR) HgCdTe electron avalanche photodiodes (eAPDs) with different doping profiles have been characterized for use in SWIR gated viewing systems. Gated viewing offers enhanced image contrast in scenes with clutter from the foreground or background. HgCdTe-based eAPDs show exponential gain–voltage characteristics and low excess noise and are, therefore, well suited for active imaging applications. The gain achievable at a fixed reverse voltage varies with the bandgap of the Hg_1?xCd_xTe detector material. We analyze current–voltage and gain–voltage plots measured on SWIR Hg_1?xCd_xTe eAPDs with x?=?0.45, corresponding to a cutoff wavelength of 2.55 μm at 150 K. The cutoff has been chosen as a trade-off between achievable APD gain and operating temperature for SWIR gated-viewing systems with target distances of about 1000 m. Focal plane arrays with a readout-integrated circuit featuring a fast internal clock have been built and their performance with respect to gated viewing applications has been evaluated on a laboratory demonstrator for short distances. Future plans for a field demonstrator for distances up to 1000 m are described briefly at the end.     

Thermally excited silicon microactuators

A cantilever-type micromachined silicon actuator based on the bimetal effect used extensively for the fabrication of temperature-controlled electrical switches is described. The silicon actuator consists of a Si-metal sandwich layer and an integrated poly-Si heating resistor as a driving element. Due to the low heat capacity of the transducer element, a high temperature increase per input power unit can be achieved. For a (Si-Au)-cantilever-type actuator, 500-μm long and several micrometers thick, a specific deflection of approximately 0.1 μm/K at the free end has been measured. The design considerations, fabrication process, and experimental results of the actuator are discussed     

Pulsed, laser-induced holographic coupling gratings for waveguides made of cross-linkable polymers

We report a simple and efficient laser-pulse technique for producing surface-relief gratings in polymer waveguides. The gratings are created in the non-cross-linked sample areas of waveguides by exposure to the interference pattern of frequency-doubled Nd:YAG laser pulses in a dual-beam interferometer. Since light does not affect the cross-linked portions of the samples, our technique is particularly appropriate for channel waveguides created by selective bleaching and/or cross linking.     

Magnetic films for electromagnetic actuation in MEMS switches

Microsystem Technologies - This paper investigates the fabrication of magnetic films via electroplating to be applied into electromagnetic actuated micro electro-mechanical systems (MEMS) switches....     

GMES4Mining: GMES-based Geoservices for Mining to Support Prospection and Exploration and the Integrated Monitoring for Environmental Protection and Operational Security

The GMES4Mining R&D project started in summer 2011 with the purpose of supporting management in all phases of a mining cycle. In most states of the European Union, the mines are in phases of operation or reclamation, but in other countries there is an interest in prospecting and exploring new areas for mining. In order to support the implementation of legal responsibilities, GMES4Mining investigates the potential of innovative remote sensing technologies for mining monitoring, prospection and exploration. In an early phase of this GMES4Mining project, a detailed query on the users’ requirements on remote sensing was performed. Currently, spaceborne radar data and ground measurements are tested for an early detection of slope slides in operational mines, slope stability in dumps, surface ground movements and subsidence. Satellite- and air-borne optical remote sensors are meant to monitor changes in ground water depth, directly through the estimation of soil moisture or indirectly by mapping changes in vegetation, both in the exploitation and the reclamation phases. For the scope of the GMES4Mining project two study sites were selected in the northern part of the German Ruhrgebiet. An important scope of the project is to report the quality of data and methods. Moreover, the results of the research will be integrated in a spatial data infrastructure (SDI) and disseminated via a web portal. This paper gives an introduction to the project and its different parts.     

Photo‐aligned anisotropic optical thin films

Abstract— Photo‐alignment of anisotropic optical thin films enables realization of novel optical elements, which were not feasible up until now. Photo‐aligned anisotropic thin films can be applied to rigid or flexible substrates, which may be flat or curved. The optical performance of such films can be tailored to application‐specific requirements by introducing tilt profiles of the optical axis and/or generate patterned retarders with continuous or periodical in‐plane variation of the optical axis.