Piezoelectrically actuated four-bar mechanism with two flexible links for micromechanical flying insect thorax

In this paper, a piezoelectrically actuated four-bar mechanism with two flexible links is proposed to be used in a micromechanical flying insect robot wing thorax for stroke amplification. PZT-5H- and PZN-PT-based unimorph actuators are utilized at the input link of the four-bar for a compact and lightweight thorax transmission mechanism. The kinematics and dynamics of the proposed wing structure with two parallel four-bar mechanisms are analyzed, optimal four-bar link size selection method is introduced, and quasistatic forces generated at the wing are computed for evaluating the feasibility of the design. Using laser micromachining and folding techniques, prototype four-bar structures are constructed. In the experiments, for a 10/spl times/1/spl times/0.12 mm/sup 3/ PZT-5H actuator-based four-bar mechanism, the stroke amplification of around 20 - 25 is held, and an attached polyester wing is resonated at 29 Hz with around 90/spl deg/ flapping motion. These results match closely with the predicted theoretical values.     

Robust decoding of variable-length encoded Markov sources using a three-dimensional trellis

In this letter, we present an improved index-based a-posteriori probability (APP) decoding approach for the error-resilient transmission of packetized variable-length encoded Markov sources. The proposed algorithm is based on a novel two-dimensional (2D) state representation which leads to a three-dimensional trellis with unique state transitions. APP decoding on this trellis is realized by employing a 2D version of the BCJR algorithm where all available source statistics can be fully exploited in the source decoder. For an additional use of channel codes the proposed approach leads to an increased error-correction performance compared to a one-dimensional state representation.     

Extractive Properties of Synergistic Mixtures of Dipicolinic Acid Diamides and Chlorinated Cobalt Dicarbollide

Extraction of Cs, Sr, Eu, U, Np, and Am with mixtures of dipicolinic acid diamides with chlorinated cobalt dicarbollide was studied. A synergistic effect was revealed.     

An Acoustic Converter Used to Measure Ionizing Radiation Energy Loss

A monitor is proposed based on ultrasonic production when ionizing radiation passes through a medium. The recording element is a 0.2 mm aluminum plate mounted in a ceramic acoustic converter AC in the form of a wedge of thickness 2 mm. The low plate thickness minimizes the beam parameter distortion, while special technology used in the AC provides high sensitivity. The device has been calibrated in the proton beam from the ITEP accelerator at 200 MeV with 2·10⁹–6·10¹⁰ particles in a pulse and a pulse length of 70 nsec.     

Theoretical analysis of cladding-mode waveguide dispersion and its effects on the spectra of long-period fiber grating

A new method to control the free spectral range (FSR) of a long-period fiber grating (LPFG) is proposed and theoretically analyzed. As the refractive index decreases radially outward in the silica cladding by graded doping of fluorine, waveguide dispersion in the cladding modes was modified to result in the effective indexes change and subsequently the phase-matching conditions for coupling with the core mode in a LPFG. Enlargement of the FSR in a LPFG was theoretically confirmed.     

Multilayer power printed structures suitable for controlling EMI noises generated in power converters

Electromagnetic interference (EMI) noises generated in power converters are diffused on the surface of conductors. This means influences occur from radiated EMI noises emitted from power transmission lines as well as conducted EMI noises transmitted from them. EMI noises diffusing on the surface of conductors are generally difficult to control using conventional concentrated constant theory. Thus, a new approach based on distributed constant circuit theory is needed in order to control EMI noises. A power converter structure to control EMI noises using multilayer power printed circuit technology is studied in this paper. A structure which can control EMI noises should simultaneously satisfy two conditions, i.e., one to shut down and one to attenuate EMI noises. The structure satisfying these conditions is studied through simulations using the Transmission-Line Modeling Method. The simulations show that the diffusion of EMI noises is controlled by dividing the flow of currents produced by EMI noises into the horizontal and perpendicular directions. That is, the horizontal current flow is controlled inside using the differences in the resistance produced from differences between inner and outer diameter of power transmission lines and the perpendicular current flow can be controlled by properly designing the thickness of the dielectric layer sandwiched between P-and N-power transmission lines with the symmetrical structure. Moreover, it is confirmed by simulations and experiments that the attenuation of EMI noises is affected by the width of the power transmission lines. It is expected that the results obtained in this paper can provide important rules when designing power converters with EMI noise control functions which use the multilayer power printed circuit technology.     

Analogue switch for very low-voltage applications

A new analogue switch suitable for operation at very low-voltage supply in a standard CMOS technology is presented. The proposed switch is based on 'quasi-floating-gate' transistors and has a simple and compact structure. For illustrative purposes, two sample-and-hold circuits operating from a single supply voltage close to the threshold voltage of a transistor, and using the proposed technique, are presented. Experimental results obtained from prototypes in a 1.5 /spl mu/m CMOS technology are provided.