Plasma chemistries for dry etching of NiFe and NiFeCo

Plasma chemistries based on chlorine, bromine, or iodine have been investigated for inductively coupled plasma etching of NiFe and NiFeCo. There is clear evidence of a chemically enhanced etch mechanism with both Cl₂- and I₂- based mixtures, with no enhancement present for Br₂ chemistries. Etch yields are typically low (≤0.25), emphasizing the need for high ion fluxes in order to achieve practical material removal rates.     

Polypropylene alloy filaments dyeable with disperse dyes

Polypropylene fibres which can be conventionally dyeable using disperse dyes have been prepared by alloying with nylon 6 and a polypropylene grafted maleic anhydride compatibiliser during extrusion. The dyeing performance of fibres containing various amounts of these components has been assessed.     

The current injection method for AC plasma display panel (PDP) sustainer

A new concept of energy recovery for a plasma display panel (PDP) is proposed. Different from conventional LC resonant sustaining drivers, the current built up before inverting the polarity of the panel electrodes is utilized to change the panel polarity together with energy previously charged in panel capacitance. This operation provides zero-voltage switching of switches and reduction of electromagnetic interference by rejecting the surge current when the sustain switches are turned on. The buildup current helps to reduce the transition time of the panel polarity and may produce more stable light waveforms. This method is suitable for a PDP sustaining driver requiring stable light emission characteristic while it maintains low circuit loss like the series-resonant-type energy recovery circuit which is known to be a very effective method.     

RF, DC, and reliability characteristics of ALD HfO/sub 2/-Al/sub 2/O/sub 3/ laminate MIM capacitors for Si RF IC applications

High-performance metal-insulator-metal capacitors using atomic layer-deposited HfO/sub 2/-Al/sub 2/O/sub 3/ laminate are fabricated and characterized for RF and mixed-signal applications. The laminate capacitor can offer high capacitance density (12.8 fF//spl mu/m/sup 2/) up to 20 GHz, low leakage current of 4.9/spl times/10/sup -8/ A/cm/sup 2/ at 2 V and 125/spl deg/C, and small linear voltage coefficient of capacitance of 211 ppm/V at 1 MHz, which can easily satisfy RF capacitor requirements for year 2007 according to the International Technology Roadmap for Semiconductors. In addition, effects of constant voltage stress and temperature on leakage current and voltage linearity are comprehensively investigated, and dependences of quadratic voltage coefficient of capacitance (/spl alpha/) on frequency and thickness are also demonstrated. Meanwhile, the underlying mechanisms are also discussed.     

External Cavity Lasers Composed of Higher Order Gratings and SLDs Integrated on PLC Platform

Very compact 4‐channel 200‐GHz‐spacing external cavity lasers (ECLs) were fabricated by hybrid integration of reflection gratings and superluminescent laser diodes on a planar lightwave circuit chip. The fifth‐order gratings as reflection gratings were formed using a conventional contact‐mask photo‐lithography process to achieve low‐cost fabrication. The lasing wavelength of the fabricated ECLs matched the ITU grid with an accuracy of ×0.1 nm, and optical powers were more than 0.4 mW at the injection current of 80 mA for all channels. The ECLs showed single mode operations with more than 30 dB side lobe suppression.     

Poly(cytidylic acid) and poly(adenylic acid) analogues: synthesis and catalytic activity for hydrolysis of dinucleotides and nucleic acids

Poly(cytidylic acid) and poly(adenylic acid) analogues, resembling closely the structures of the natural polymers, were synthesized by the alternating cyclocopolymerization of a nucleoside derivative and acrylic anhydride, and subsequent hydrolysis. The polymers catalyzed the cleavage of dinuleotides and nucleic acids (DNA and RNA). Poly(cytidylic acid) and poly(adenylic acid) analogues accelerated the hydrolysis of GpG and TpT, respectively, faster than other dinucleotides due to the base pairing.     

Individual substitutions of clustered arginine residues of the sensor kinase KdpD of Escherichia coli modulate the ratio of kinase to phosphatase activity

Escherichia coli responds to K+ limitation or high osmolarity by induction of the kdpFABC operon coding for the high affinity K+-translocating Kdp-ATPase. KdpD, the sensor kinase of this system, is a bifunctional enzyme catalyzing the autophosphorylation by ATP and the dephosphorylation of the corresponding response regulator KdpE. Here we demonstrate that individual replacements of clustered arginine residues located close to transmembrane domain TM4 modulate the ratio of kinase to phosphatase activity. Thus KdpD-Arg511 --> Gln is characterized by an increase in the kinase activity and a loss of the phosphatase activity. However, when Arg at position 511 is replaced with Lys, activities of the corresponding protein are comparable with wild-type KdpD. In contrast, replacement of arginine residues at positions 503, 506, or 508 with glutamine or lysine causes a decrease of the kinase and an increase of the phosphatase activities. Changes of the activities of these KdpD proteins correspond with alterations in kdpFABC expression. Thus KdpD-Arg511 --> Gln causes constitutive expression of kdpFABC. KdpD proteins with Arg replacements at positions 503, 506, or 508 are unable to respond to osmolarity, whereas the sensing of K+ limitation is not influenced. Simultaneous replacement of arginine residues 508 and 511 or 506, 508, and 511 with glutamine leads to a decrease of the phosphatase activity. However, kdpFABC expression is dependent on K+ and osmolarity. Finally, when Arg513 is replaced with glutamine the amount of KdpD detected in the membrane is drastically reduced. These results imply that there is an equilibrium between the kinase and phosphatase activities of KdpD, which can be shifted by the replacement of one arginine residue. An electrostatic switch mechanism within the protein is proposed through which the ratio of kinase to phosphatase is regulated. Finally, these results lend support to the notion that KdpD can be activated by two distinct stimuli, K+ limitation and osmolarity.     

Pinch-Off Voltage-Adjustable High-Voltage Junction Field-Effect Transistor

In this letter, a novel type of high-voltage n-channel junction field-effect transistor (JFET) was designed using a conventional n-channel laterally diffused metal-oxide-semiconductor (n-LDMOS) without changing any step in the process. High-voltage JFET can be a start-up device in power factor correction, dc-ac converters, and ac-dc converters for providing a self-powered circuit and minimizing standby power losses without gate control because of its negative threshold voltage. Experimental results show that an n-LDMOS with this JFET structure can achieve a reverse blocking voltage of more than 700 V with very low leakage current. The pinch-off voltage can be designed by changing n-well width to meet the circuit requirement.     

Semiactive Neurocontrol for Seismic Response Reduction Using Smart Damping Strategy

A new semiactive control strategy that combines a neurocontrol system with a smart damper is proposed to reduce seismic responses of structures. In the proposed semiactive control system, the improved neurocontroller, which was developed by employing a training algorithm based on a cost function and a sensitivity evaluation algorithm to replace an emulator neural network, produces the desired active control force, and then a bang-bang-type controller clips the control forces that cannot be achieved by a smart damper (e.g., a variable orifice damper, controllable fluid damper, etc.). Therefore, the proposed semiactive control strategy is fail-safe in that the bounded-input, bounded-output stability of the controlled structure is guaranteed. Numerical simulation results show that the proposed semiactive control system that employs a neural network-based control algorithm is quite effective in reducing seismic responses.