Analysis of a 0.1-μm stepping bi-axis piezoelectric stage using a 2-DOF lumped model

Piezoelectric stages are widely used for parts manipulation, including micro-component assembly and bio-cell manipulation. This paper proposes a bi-axis piezoelectric stage based on a friction driven mechanism. The carrier slides on a supporting frame and slider constructed in the same plane as a low-profile stage. The dynamic model of the friction driven is based on a 2-DOF lumped model considering the impact and separation behavior. The first mass is the bulk piezoelectric actuator (slab)—as a vibrator—and the second is the driven slider. The stiffness ratio of the piezoelectric slab-to-the driven slider affects the output force of the slider because of the contact time ratio. Moreover, the stepping size is adjusted according to the duty ratio of the pulse width of the driving signal. The stepping size of 0.1 μm is achieved in the X and Y axes corresponding to 3% and 5% of the duty ratio, respectively, of 512-Hz carrier frequency in 20-Vpp driving signal. When the duty ratio is 100%, the full speed of 18 and 16 mm/s are achieved in the X- and Y-axes, respectively. The dimensions of the piezoelectric stage are 61 × 58 × 21.3 (high) mm³.

     

The Motivating Impact of Informing Women Smokers of a Link Between Smoking and Cervical Cancer: The Role of Coherence.

This research assessed the role of having a coherent explanation of the link between smoking and cervical cancer in motivating women to stop smoking. In the 1st study, women were given a leaflet with either a detailed or a minimal explanation of the link or no leaflet. The leaflets were similarly effective at providing a coherent explanation. In a cross-sectional analysis, having a coherent explanation moderated the relationship between perceived vulnerability and intention: Higher perceived vulnerability to cervical cancer was associated with greater intention to quit smoking only amongst women with a more coherent explanation of the link between smoking and cervical cancer. This rinding was replicated in a 2nd study. These results are consistent with H. Leventhal et al.'s (1997) self-regulatory model, which suggests that motivation to change behavior depends not only on perceiving a threat but also on having a coherent model linking the behavior with the threat. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

One-step pointer forwarding strategy for location tracking indistributed HLR environment

One of the main challenges in personal communication service (PCS) is to locate many mobiles that may move frequently from place to place. Such a system operation is called location tracking. Many network signals flow, and database queries are required to achieve such a task. In addition to the two-level hierarchical strategy in IS-41 and GSM, several strategies have been proposed to improve the efficiency of location tracking. Pointer forwarding was used to reduce the expensive home location register (HLR) accesses. Previously, the distributed HLR scheme was proposed to prevent the HLR from becoming a bottleneck in the signaling network. However, the length of a forwarding pointer chain may be lengthened in a distributed HLR environment. We propose a more efficient strategy to overcome this potential problem. This strategy attempts to migrate the locating chains in a distributed HLR system when a mobile issues a registration operation. As a consequence, the length of any forwarding pointer chain does not exceed one in our strategy. Simulation results indicate that our strategy significantly decreases the locating cost. In fact, this strategy provides an upper bound of location tracking time owing to the fact that the length of any locating path does not exceed one. Furthermore, obsolete entries in local databases visitor location registers can be reclaimed in this strategy     

Synthesis of Solid Phosphate Compounds of Ti(III) and Ti(IV)

Several new methods for the synthesis of TiPO₄ are described. Crystalline phosphate compounds containing boron and titanium in a single III or mixed (III, IV) oxidation states have been synthesized and identified by X-ray diffraction. An additional family of phosphate compounds containing only Ti(III, IV) has also been synthesized and identified. All the compounds exhibit attractive colors, e.g., bright green, blue, purple, and black, and are stable at room temperature in air and in boiling water.