Reaction of Fullerenes with Radicals Generated by Thermal Decomposition of Azo Compounds

Radicals generated thermally from azo compounds having cyano or ester function were added to C₆₀ to give poly-functionalized C₆₀ derivatives. Interestingly, their reactivities toward C₆₀ were found to be higher than those toward C₇₀.     

Performance analysis of a time diversity ARQ in land mobile radio

A time diversity automatic repeat-request (ARQ) scheme with a finite number of transmissions is investigated for a digital FM mobile radio with frequency demodulation (FD). It processes all the retransmissions of a single data block using postdetection diversity combining. The analysis of the signal energy per bit required for a given bit error rate (BER) and the spectral efficiency in a cellular mobile radio system are presented. The results obtained from the numerical calculations show that this ARQ scheme offers a performance superior to both the basic ARQ scheme and the time-diversity scheme     

Rates of dissolution of solid iron,cobalt, nickel,and silicon in liquid copper and diffusion rate of iron from liquid Cu-Fe alloy into liquid copper

Consideration is given to the previously reported data on the observed dissolution rate of the vertical peripheries of cylindrical iron, cobalt, and nickel in liquid copper at temperatures in the range of 1468 to 1653 K under natural convection. The observed steady-state rate is close to the rate calculated from an equation expressed in terms of the activity of solute for dissolution rate controlled by mass transfer through a boundary layer in the liquid. The dissolution rate of the horizontal bottom face of cylindrical cobalt in liquid copper is determined at 1573 to 1574 (±6) K in the absence of fluid flow. The decrease in height of the cylinder, z(m), obeys z = α √t where t is time (s) and α is 4.18 × 10⁻⁶ m · s^−1/2. This value is in close agreement with the calculated one based on an equation expressed in terms of the activity of solute for dissolution rate controlled by non-steady-state diffusion in the liquid. Experiments have been carried out to explore the dissolution rates of one vertical edge of a square silicon plate and the horizontal bottom face of a silicon disk in liquid copper at ∼1473 K. The rate at the lowest part of the vertical edge ranges from 39 to 69 mol · m⁻² · s⁻¹, and the calculated rate based on the former equation is close to the average of the maximum and minimum observed values. The ratios of these observed dissolution rates to those of iron, cobalt, or nickel under natural convection are in the range of 74 to 910. In the dissolution of the horizontal bottom face, the value of α is estimated from another equation in which the densities of solid and liquid different from each other and the activity of solute are taken into account. This estimated value is in the range of the observed ones. The total amounts of iron diffused from liquid Cu-Fe alloy into liquid copper within capillaries at 1574 K are determined. Their average is expressed as a function of the activity of iron.     

Relation between liver amino acid-catabolizing enzymes and free amino acids of liver and plasma in adult cockerels fed diets containing graded levels of protein

Activities of liver amino acid-catabolizing enzymes and liver and plasma free amino acid concentrations in adult cockerels fed diets containing 3% to 21% casein were determined 2 hours after a meal. Liver tryptophan pyrrolase activity and liver tryptophan increased with an increase in dietary casein level, but plasma tryptophan decreased with the increase dietary casein level. As the dietary casein level increased, liver lysine-ketoglutarate reductase activity decreased, but liver and plasma lysine increased proportionally, and the rate of increase was larger in the plasma than in the liver. Liver phenylalanine hydroxylase activity increased with the increase in dietary casein level from 3% to 12%, and thereafter remained unchanged. Reflecting the change of this enzyme, phenylalanine increased in the liver and decreased in the plasma with the increase in dietary casein level from 3% to 12%, and thereafter the rate of increase in liver phenylalanine became small and plasms phenylalanine increased. Liver tyrosine was not influenced by the dietary casein level, whereas plasma tyrosine increased sharply from 3% to 12%, and thereafter the rate of increase decreased. Thus, the difference between liver and plasma free amino acid responses might be due to the changes in the activities of liver amino acid-catabolizing enzymes.     

A new approach to differential dynamic programming for discrete time systems

This paper proposes a new differential dynamic programming algorithm for solving discrete time optimal control problems with equality and inequality constraints on both control and state variables and proves its convergence. The present algorithm is different from differential dynamic programming algorithms developed in [10]-[15], which can hardly solve optimal control problems with inequality constraints on state variables and whose convergence has not been proved. Composed of iterative methods for solving systems of nonlinear equations, it is based upon Kuhn-Tucker conditions for recurrence relations of dynamic programming. Numerical examples show file efficiency of the present algorithm.     

Assimilation of liquid hydrocarbon by microorganisms. II. Growth kinetics

The growth kinetics of a microorganism with high affinity for liquid hydrocarbon which has a low solubility in water was investigated for Candida intermedia IFO 0761 in our previous work. The microorganism contained a hydrocarbon pool in and/or on the cell. The transfer of water-soluble substrates to the cell was not the rate-limiting step in the growth of C. intermedia accompanied by clump formation with liquid hydrocarbon. The operating conditions necessary for the oxygen supply for the growth were adequate for the growth of C. intermedia on n-tetradecane. The saturation kinetics was valid for the specific growth rate of C. intermedia and specific concentration of hydrocarbon per unit cell mass; the specific growth rate was expressed by the following equation: (formula: see text).     

A 5.6 MIPS call-handling processor for switching systems

A 32 bit call-handling processor for an electronic switching system (ESS) capable of a 5.6 MIPS instruction execution rate is discussed. The processor uses a mixed architecture consisting of a reduced instruction set computer (RISC) and a complex instruction set computer (CISC) to economize the instruction execution, and features a four-stage two-way pipeline and local storage for the RISC and writable control storage for the CISC. To obtain reliability, availability, and serviceability, such functions as parity check/generation, microdiagnostic, and matcher have been incorporated within the chip. The chip contains about 160 K transistors within a chip size of 13.2×13.7 mm². A 1.2 μm double-metal CMOS technology has been used. In designing the chip layout, a compromise between manual and automatic placing or routing was adopted which enabled a reasonably short design time     

Magnetic Tunnel Junctions for Spintronic Memories and Beyond

In this paper, recent developments in magnetic tunnel junctions (MTJs) are reported with their potential impacts on integrated circuits. MTJs consist of two metal ferromagnets separated by a thin insulator and exhibit two resistances, low (R_p) or high (R_ap) depending on the relative direction of ferromagnet magnetizations, parallel (P) or antiparallel (AP), respectively. Tunnel magnetoresistance (TMR) ratios, defined as (R_ap $R_p)/R_p as high as 361%, have been obtained in MTJs with Co₄₀Fe₄₀B₂₀ fixed and free layers made by sputtering with an industry-standard exchange-bias structure and post deposition annealing at Ta = 400 degC. The corresponding output voltage swing DeltaV is over 500 mV, which is five times greater than that of the conventional amorphous Al-O-barrier MTJs. The highest TMR ratio obtained so far is 500% in a pseudospin-valve MTJ annealed at Ta = 475 degC, showing a high potential of the current material system. In addition to this high-output voltage swing, current-induced magnetization switching (CIMS) takes place at the critical current densities (J_CO) on the order of 10⁶ A/cm² in these MgO-barrier MTJs. Furthermore, high antiferromagnetic coupling between the two CoFeB layers in a synthetic ferrimagnetic free layer has been shown to result in a high thermal-stability factor with a reduced J_CO compared to single free-layer MTJs. The high TMR ratio enabled by the MgO-barrier MTJs, together with the demonstration of CIMS at a low J_CO, allows development of not only scalable magnetoresistive random-access memory with feature sizes below 90 nm but also new memory-in-logic CMOS circuits that can overcome a number of bottlenecks in the current integrated-circuit architecture