A novel damping scheduling scheme for proximate time optimal servomechanisms in hard disk drives

The proximate time-optimal servomechanism (PTOS) is widely used in hard disk drives because of its simplicity and good performance. There have been many studies to improve PTOSs, though they are complex or need a time-consuming tuning process. Here, we propose a novel damping scheduling PTOS (DSPTOS) for hard disk drives. The proposed algorithm keeps the closed-loop damping coefficient at a predetermined value. Compared to the original PTOS, smaller damping in deceleration will boost the rising speed, and larger damping in the settling phase reduces the overshoot and residual vibrations. Moreover, the DSPTOS maintains the simplicity of the PTOS by introducing just a predetermined damping coefficient. We applied the proposed DSPTOS algorithm to a voice coil motor in a hard disk drive. Through simulations and real-time experiments, we verified the effectiveness of the DSPTOS. In particular, with respect to long stroke seeks, the DSPTOS performs better than the PTOS.     

Sulfide treated GaAs MISFET's with gate insulator of photo-CVDgrown P3N5 film

Sulfide passivated GaAs MISFET's with the gate insulator of photo-CVD grown P₃N₅ films have been successfully fabricated. The device shows the drain current instability less than 22% for the period of 1.0 s ~1.0×10⁴ s, due to excellent properties of sulfide treated P₃N₅/GaAs interface. The effective electron mobility and extrinsic transconductance of the device are about 1300 cm²/V·sec and 1.33 mS, respectively, at room temperature. To estimate the effects of sulfide treatment on P₃N₅/GaAs interfacial properties, GaAs-MIS diodes are also fabricated     

An efficient charge recovery logic circuit

Efficient charge recovery logic (ECRL) is proposed as a candidate for low-energy adiabatic logic circuit. Power comparison with other logic circuits is performed on an inverter chain and a carry lookahead adder (CLA). ECRL CLA is designed as a pipelined structure for obtaining the same throughput as a conventional static CMOS CLA. Proposed logic shows four to six times power reduction with a practical loading and operation frequency range. An inductor-based supply clock generation circuit is proposed. Circuits are designed using 1.0-μm CMOS technology with a reduced threshold voltage of 0.2 V     

Characterization and chromosomal mapping of two pseudogenes of the mouse Pafaha/Lis1 gene: retrointegration hotspots in the mouse genome

This study examines the relationship between trainees' conjugal family experience, current intergenerational family relationships, and the client's perception of the therapeutic alliance. Participants were 74 first practicum family therapy trainees, representing two family therapy programs, and 90 clients. Results indicated a moderately significant relationship between conjugal family experience and trainees' reported intergenerational intimacy with parents. Additionally, clients whose therapists had conjugal family experience reported a slightly more favorable therapeutic alliance than clients whose therapists did not have conjugal family experience. Additionally, trainees with conjugal family experience reported more current intimacy and individuation than nonconjugal trainees and felt less intimidated by their parents.     

High-throughput mass spectrometer using atmospheric pressure ionization and a cylindrical ion trap array

The analytical performance of an atmospheric pressure sampling, multiple-channel, high-throughput mass spectrometer was investigated using samples of a variety of types. The instrument, based on an array of cylindrical ion traps, was built with four independent channels and here is operated using two fully multiplexed channels (sources, ion optics, ion traps, detectors) capable of analyzing different samples simultaneously. Both channels of the instrument were incorporated within the same vacuum system and operated using a common set of control electronics. A multichannel electrospray ionization source was assembled and used to introduce samples including solutions of organic compounds, peptides, and proteins simultaneously into the instrument in a high-throughput fashion. Cross-talk between the channels of the instrument occurred in the detection system and could be minimized to 1-2% using shielding between detector channels. In this initial implementation of the instrumentation, an upper mass/charge limit of approximately 1300 Th was observed (+13 charge state of myoglobin) and unit mass/charge resolution was achieved to approximately 800 Th. The rather limited dynamic range (2-3 orders of magnitude for low-concentration analytes) is due to cross-talk contributions from more concentrated species introduced into a different channel. Analysis of mixtures of alkylamines and peptides is demonstrated, but analysis of mixtures with a wide spread in mass/charge ratios was not possible due to mass discrimination in the ion optics. Further refinement of the vacuum system and ion optics will allow the addition of more channels of parallel mass analysis and facilitate applications in fields such as proteomics and metabolomics.     

Monodispersed spherical colloids of Se@CdSe: synthesis and use as building blocks in fabricating photonic crystals

Monodispersed spherical core-shell colloids of Se@Ag(2)Se have been exploited as a chemical template to synthesize Se@CdSe core-shell particles using a cation-exchange reaction. A small amount of tributylphosphine could facilitate the replacement of Ag(+) by Cd(2+) in methanol at 50 degrees C to complete the conversion within 150 min. The orthorhombic structure of beta-Ag(2)Se changed to a well-defined wurtzite lattice for CdSe. The CdSe shells could be converted back to beta-Ag(2)Se by reacting with AgNO(3) in methanol at room temperature. Because of the uniformity in size and high refractive index associated with the Se@CdSe core-shell colloids, they could serve as a new class of building blocks to fabricate photonic crystals with wide and strong stop bands.     

The dependence of the critical current of Nb3Sn tapes on the direction of a transverse magnetic field

A theoretical and experimental study has been made of the critical current of Nb₃Sn tapes prepared by different methods as a function of direction and magnitude of the applied transverse magnetic field. For different orientations of the magnetic field with respect to the crystal grains the pinning is calculated for hypothetical sinusoidal and ellipsoidal shapes of the grains. By comparing the theoretical and experimental results we conclude that for diffusion-processed Nb₃Sn tapes the grains are almost ellipsoidal, whereas for vapor-deposited tapes they are more sinusoidal. Finally, we explain the possibility of formation of such grain shapes in the process of their creation.