STW resonances on corrugated plates of finite thickness

Propagation of surface transverse waves on a corrugated plate has been analysed. Results are presented for both thin and thick isotropic plates, showing that the dispersion curves for the lowest mode correspond in the second case to a semi-infinite substrate. A frequency equation is developed for planar resonators based on this type of wave propagation, applicable to both isotropic and rotated Y-cut trigonal plates.     

计算机辅助设计大大简化了功率因素变换器的设计

由于能源调节的持续增长，电源变得越来越复杂。人们意识到需要一个更简单的方式进行设计时，出现了计算机辅助设计工具。这篇文章就论述了此工具如何很快产生一个连续导通模式升压功率因素校正设计的优势。全部设计已经得到证实，并且会提供一些相关的公式。     

DUV-induced micro and nanopatterning of polymer plasma deposited films

A simple method is described for patterning polymer surfaces with reactive groups. This entails pulsed plasma deposition of anhydride functionalized films, followed by DUV irradiation using a ArF excimer laser. Micro and nano-scale patterning was demonstrated, leading to well defined structures with controlled chemistry and/or geometries. We investigated the chemical changes induced by DUV irradiation. Among other parameters, we demonstrated that the covalent attachment of an amine terminated nucleophile via the aminolysis improved significantly the DUV photosensitivity. Using this approach it was possible to create combinatorial patterned surfaces. In particular such patterned polymer films appear as excellent candidate to study the effect of nanostructuration on the development of biofilms.     

Integrated structure and control design for mechatronic systems with configuration-dependent dynamics

This paper considers the optimal design of mechatronic systems with configuration-dependent dynamics. An optimal mechatronic design requires that, among the structural and control parameters, an optimal choice has to be made with respect to design specifications in the different domains. Two main challenges are treated in this paper: the non-convex nature of the optimization problem and the difficulty in modeling serial machines with flexible components and their embedded controllers. The optimization problem is treated using the direct design strategy which considers simultaneously structural and control parameters as variables and adopts non-convex optimization algorithms. Linear time-invariant and gain-scheduling PID controllers are addressed. This methodology is exploited for the multi-objective optimization of a pick-and-place assembly robot with a gripper carried by a variable-length flexible beam. The resulting design tradeoffs between system accuracy and control efforts demonstrate the advantage of an integrated design approach for mechatronic systems with configuration-dependent dynamics.     

Efficient Scattering Calculations in Complex Backgrounds

The utilization of the Green's tensor associated with a complex optical background (surface, cavity or stratified medium) leads to a dramatic reduction of the computation effort associated with scattering calculations in that background. This approach is illustrated with examples where a mere change of the background Green's tensor makes possible the investigation of completely different physical situations. Two different discretization approaches are compared and similarities between the Green's tensor technique and the Method of Lines are emphasized; in the latter, the utilization of analytic solutions in one specific direction also reduces the discretization of the system.     

Registration and real-time visualization of transcranial magnetic stimulation with 3-D MR images

This paper describes a method for registering and visualizing in real-time the results of transcranial magnetic stimulations (TMS) in physical space on the corresponding anatomical locations in MR images of the brain. The method proceeds in three main steps. First, the patient scalp is digitized in physical space with a magnetic-field digitizer, following a specific digitization pattern. Second, a registration process minimizes the mean square distance between those points and a segmented scalp surface extracted from the magnetic resonance image. Following this registration, the physician can follow the change in coil position in real-time through the visualization interface and adjust the coil position to the desired anatomical location. Third, amplitude of motor evoked potentials can be projected onto the segmented brain in order to create functional brain maps. The registration has subpixel accuracy in a study with simulated data, while we obtain a point to surface root-mean-square error of 1.17+/-0.38 mm in a 24 subject study.     

A patient-mounted robotic platform for CT-scan guided procedures

In this paper, we present a novel robotic assistant dedicated to medical interventions under computed tomography scan guidance. This compact and lightweight patient-mounted robot is designed so as to fulfill the requirements of most interventional radiology procedures. It is built from an original 5 DOF parallel structure with a semispherical workspace, particularly well suited to CT-scan interventional procedures. The specifications, the design, and the choice of compatible technological solutions are detailed. A preclinical evaluation is presented, with the registration of the robot in the CT-scan.     

Adaptive gain and delay mismatch cancellation for LINC transmitter

Linear amplification with Nonlinear Component (LINC) transmitter architecture is an efficient solution for high efficiency amplification of signals. Nonetheless, this solution suffers both from gain impairment and delay mismatch between the two signal paths. Indeed, a mismatch in propagation time between the paths degrades the quality of the transmit signal but also disrupts the convergence of the gain correction algorithm resulting in a degradation of its performance. In this paper, we present an adaptive algorithm based on a gradient descent formulation for the identification and correction of these delays. We also demonstrate its effectiveness when applied prior to the gain adjustment procedure. The identification approach is preferred here, to ensure monitoring facilities.     

JP3D compressed-domain watermarking of still and volumetric medical images

Digital watermarking can be used as data hiding technique to interleave medical images with patient information before transmitting and storing applications. While digital image watermarking and lossy compression methods have been widely studied, much less attention has been paid to their application in medical imaging situations, due partially to speculations on loss in viewer performance caused by degradation of image information. This article describes an hybrid data hiding/compression system, adapted to medical imaging. The central contribution is to integrate blind watermarking, based on turbo trellis-coded quantization, to JP3D encoder. The latter meets conformity condition, with respect to its antecedents JPEG2000 coders. Thus, the watermark embedding can be applied on two-dimensional as well as volumetric images. Results of our method applied to magnetic resonance and computed tomography medical images have shown that our watermarking scheme is robust to JP3D compression attacks and can provide relative high data embedding rate whereas keep a relative lower distortion.     

Measurement of fractional order model parameters of respiratory mechanical impedance in total liquid ventilation

This study presents a methodology for applying the forced-oscillation technique in total liquid ventilation. It mainly consists of applying sinusoidal volumetric excitation to the respiratory system, and determining the transfer function between the delivered flow rate and resulting airway pressure. The investigated frequency range was f ∈ [0.05, 4] Hz at a constant flow amplitude of 7.5 mL/s. The five parameters of a fractional order lung model, the existing "5-parameter constant-phase model," were identified based on measured impedance spectra. The identification method was validated in silico on computer-generated datasets and the overall process was validated in vitro on a simplified single-compartment mechanical lung model. In vivo data on ten newborn lambs suggested the appropriateness of a fractional-order compliance term to the mechanical impedance to describe the low-frequency behavior of the lung, but did not demonstrate the relevance of a fractional-order inertance term. Typical respiratory system frequency response is presented together with statistical data of the measured in vivo impedance model parameters. This information will be useful for both the design of a robust pressure controller for total liquid ventilators and the monitoring of the patient's respiratory parameters during total liquid ventilation treatment.