Piezoelectrically actuated tunable capacitor

This paper describes the design, fabrication, and characterization of the first MEMS piezoelectric tunable capacitors employing zinc oxide (ZnO) actuation. Relatively simple design rules for the device-structure optimization for largest deflection are shown from simulation results based on theoretical equations. The ZnO-actuated tunable capacitors are accordingly designed and fabricated with both surface and bulk micromachining techniques. Through the surface micromachining process, sacrificial silicon is removed with XeF/sub 2/, and parylene is successfully used as a supporting layer for a piezoelectric unimorph cantilever. For comparison, other two different structures using plasma-enhanced chemical-vapor deposition (PECVD) SiN and SU-8 as supporting layers are also fabricated. Deflection analyses are performed for three specific structures, among which the parylene-supported one is demonstrated to have the largest displacement and most suitable for tunable capacitor application. For bulk-micromachined tunable capacitor, we have implemented a novel design of a large structure driven by a ZnO unimorph, and obtained a tuning ratio of more than 21:1 (0.46 pF-10.02 pF). This is the highest tuning ratio reported to date for parallel-plate tunable capacitors while requiring an applied voltage of only 35 V.     

Quantitative analysis of organochlorine pesticide residues in Chinese drugs

This paper reports the GC determination of 20 organochlorine pesticides in Chinese drugs Flos Ionicerae and Moluodan etc by the present method of Japan for determinaing pesticide residues. The results suggest that except Folium Isatidis, Radix Codonopsis and Sanqi Pian all accord with the for provisions pesticide residues in Japanese foodstuffs.     

Intracoronary infusion of E6010 has more potent thrombolytic activity than tissue plasminogen activator (t-PA) in dogs: a higher plasma level of E6010 than t-PA causes potent thrombolytic activity

We examined the thrombolytic properties of a novel modified human tissue plasminogen activator (PA) (E6010), in which cysteine 84 is replaced by serine, and which has a prolonged biologic half-life (t1/2). We compared the thrombolytic efficacy of continuous intracoronary (i.c.) infusion of E6010 with that of recombinant human tissue PA (rt-PA) in a canine model with copper coil-induced 1-h-old coronary artery thrombi and also compared the relation between thrombolytic efficacy and plasma clearance represented by pharmacokinetic parameters of i.c.-infused E6010 and rt-PA. Sixty-minute E6010 and rt-PA i.c. infusions were compared. The thrombolytic effects of i.c.-infused E6010 and rt-PA, represented by time to reperfusion (TR), reperfusion rate at 60 min (RR), and reocclusion rates at 60 min after reperfusion (OR) were as follows. E6010: Dose 0.06, 0.15, 0.3 (mg/kg/h); TR 25 +/- 10, 15 +/- 10, 13 +/- 5 (min); RR 100, 100, 100 (%); and OR 0, 0, 17 (%), respectively. Recombinant t-PA: Dose 0.06, 0.15, 0.3 (mg/kg/h); TR 47 +/- 12, 18 +/- 17, 14 +/- 4 (min); RR 50, 75, 100 (%); and OR 100, 33, 33 (%), respectively. These findings indicate that E6010 has more potent thrombolytic activity than rt-PA.(ABSTRACT TRUNCATED AT 250 WORDS)     

工艺参数对陶瓷注射成型的影响与分析

本研究通过改变注射温度，注射压力，保压压力等几个主要参数，对形状，体积不同的注射成型体，试条，圆柱及子部件进行了一系列注射工艺实验。相应地对成型体的密度，弯曲强度及烧结体的密度和强度进行测量，并从陶瓷注射成型混合物的流动行为，热物理特性方面对注射这一复杂过程进行分析，探讨工艺参数对成型过程的内在影响，从而确定合理的注射工艺条件。     

Integration of piezoelectric tunable capacitors and bonded-wire inductors for contactless RF switch and tunable filter

This paper presents the design, fabrication, and characterization of a contactless radio frequency (RF) microelectromechanical system (MEMS) switch, composed of two surface-micromachined piezoelectric tunable capacitors and two bonded-wire inductors. The measured insertion loss and power isolation of the fabricated switch are 2.2 and 10.1 dB, respectively, with a capacitance variation of 4:1 over a narrow bandwidth near 2.2 GHz. This novel approach of using inductors eases the deflection requirement for the deformable bridge of the variable capacitor, and allows piezoelectric ZnO film to be used to deflect the capacitor bridge to vary the air gap, thus yielding a contactless RF switch.     

Convergent Smoothing and Segmentation of Noisy Range Data in Multiscale Space

With few exceptions, most of the existing noise reduction and data segmentation algorithms are only suited to image data. Therefore, an adaptive smoothing algorithm, with model-based masks, within a scale space framework is proposed for range data in this paper. This algorithm smoothes range data that conform to predefined, geometric models, while leaving other data points unaffected. The convergence of the algorithm in yielding dominant features is shown based on its compliance with the anisotropic diffusion concept. The weights of the smoothing masks are adaptively calculated according to the Mahalanobis distances between range data and model-based predictions. These behave as the diffusion coefficient in the anisotropic diffusion equation, thus satisfying the requirements of the causality criterion that no new features are introduced from fine to coarse scales. The computational complexity of this algorithm is examined and compared to that of the well-known RANSAC feature extraction algorithm. Unlike RANSAC, it has the advantage that the computational complexity is less affected by increasing the order of the model, and is independent of the number of model outliers. The proposed algorithm can be used to smooth range data in multiscale space by increasing the number of smoothing iterations. Robust, robot-occlusion-invariant features are then easily extracted from the smoothed data by least squares fitting algorithms.     

Redefining the Diamond Cutting Edge: A Technique that Complements Nano-Metric Surface Generation

Ongoing developments in broadband digital networks and optical devices require mechanical components having nano-metric surface finishes and ultra precision shapes. Such components are processed using the technology of diamond micro-machining in which diamond tools are extensively used. However, these tools are susceptible to chemical attack at high temperatures and induce severe wear, especially when cutting ferrous materials. As a result, these diamond tools need to be redefined (i.e., resharpened) on a regular basis in order to facilitate micro-cutting and to generate nano-metric surface finishes. This paper describes a new way of diamond tool edge re-sharpening and its conditions to achieve both increased accuracy and material removal rate.     

A novel bit-level color image encryption using improved 1D chaotic map

Multimedia Tools and Applications - This paper introduces new simple and effective improved one-dimension(1D) Logistic map and Sine map made by the output sequences of two same existing 1D chaotic...