This work presents a monolithic DC~4GHz 6-bit digital attenuator with low insertion phase shift and attenuation error. Based on GaAs E/D pHEMT process, a serial-to-parallel converter is introduced to decrease the control pads of the chip. In the 16dB attenuation bit, a switched-path-type topology is employed in order to extend the bandwidth and achieve low insertion phase shift. The attenuator ...

It is not uncommon to use profiles to act as energy absorption parts in vehicle safety systems. This work analyses an impact attenuator based on a simple design and discusses the use of a thermoplastic material. We present the design of the impact attenuator and a mechanical test for the prototype. We develop a simulation model using the finite element method and explicit dynamics, and we evalu...

The pyrBI operon of Escherichia coli K-12 encodes the subunits of the pyrimidine biosynthetic enzyme aspartate transcarbamylase (carbamoylphosphate:L-aspartate carbamoyltransferase, EC 2.1.3.2). Expression of this operon apparently is negatively regulated by the intracellular levels of UTP. To elucidate the regulatory mechanism in which UTP functions, the nucleotide sequence of the promoter-reg...

A 5-fluorotryptophan-resistant mutant, termed 1041, was isolated from Brevibacterium lactofermentum AJ12036. The anthranilate synthase of 1041 was insensitive to feedback inhibition by tryptophan, and the specific activities of the anthranilate synthase and anthranilate phosphoribosyltransferase of 1041 were 29- and 23-fold higher than those in parental strain AJ12036, respectively. A single-ba...

The possibility of increasing the apertures of the LCLS gas attenuator/gas detector system is considered. It is shown that increase of the apertures from 3 to 6 mm, together with 4fold reduction of the operation pressure does not adversely affect the vacuum conditions upstream or downstream. No change of the pump speed and the lengths of the differential pumping cells is required. One minor mod...

This paper describes the results of optimising three process variables (control factors) to achieve a narrow line width in laser engraving of ITO conductive coatings using the Taguchi technique of experimental design. The laser used is a NEC Q-switched continuous wave (CW) Nd:YAG laser operating at a wavelength of 1.064 μm. The three process variables explored are: Q-switch frequency, speed of ...

A new type of optically controllable, millimeter-wa e ( ) ( ) ( ) MMW attenuator based on high-resisti ity high-R silicon Si wafers and a layered structure is de eloped. A high-R float-zone Si wafer is a lossless dielectric material at microwa e frequency without optical excitation. When an Si wafer is optically excited, free carriers are generated, and the Si wafer becomes a lossy dielectric. ...

A~SZFUCZ In this paper a CMOS highly linear current attenuator is described. The circuit is suited for both differential and single input currents. The current gain is electronically variable between -1 and +1 by means of two controlling currents. A simple additional circuit is described to obtain a gain that is linearly dependent on a single control current. Then the circuit can be used as a f...