Calorimetric studies of non-isothermal crystallization in amorphous Cu x Ti100−x alloys

The present paper reports the composition dependence of pre-exponential factor and activation energy of non-isothermal crystallization in amorphous alloys of Cu _x Ti_100?x system using differential scanning calorimeter (DSC) technique. The applicability of Meyer-Neldel relation between the pre-exponential factor and activation energy of non-isothermal crystallization for amorphous alloys of Cu-Ti system was verified.     

Temperature dependence of the relaxation resonance frequency of long-wavelength vertical-cavity lasers

The temperature dependence of the differential gain in AlInGaAs 1310-nm vertical-cavity lasers is investigated. The variations in differential gain and in relaxation resonance frequency are shown to depend on the room-temperature offset between the gain peak wavelength and the wavelength of the lasing mode. The tradeoff between high modulation bandwidth and good high-temperature performance for vertical-cavity lasers is analyzed. A cavity mode that is red-shifted about 25 nm from the gain peak is shown to minimize the variation in modulation bandwidth with temperature, and simultaneously allow for satisfactory high-temperature operation. Experimental results are presented and compared to calculated results with excellent agreement. Because of the change in gain-mode offset with internal temperature, the measured modulation current efficiency changed from about 2 to 4.8 GHz/mA/sup 1/2/ for an increase in drive current from 2 to 10 mA.     

Effect of oil treatments against the infestation of Callosobruchus chinensis (L.) on the levels of B vitamins in stored legumes

Groundnut, coconut and mustard oil treated whole chick pea, mung bean and pigeon pea were infested with Callosobruchus chinensis (L.) and stored for six months. Samples were analysed at monthly intervals for selected B complex vitamins viz. thiamine, riboflavin and niacin. With increase in storage period, values for all the three vitamins decreased in untreated legues. After two months of storage slight decrease in thiamine, riboflavin and niacin content of coconut oil treated legumes was observed which continued till the end of six months as compared to the other two oil treated counterparts. The storage period was associated with insect infestation, which in turn influenced the B complex vitamins of legumes. Groundnut, mustard and coconut oils were able to protect legumes for six months against insect infestation when applied in small amount (0.5%), whereas coconut oil had protective effect against insect infestation only for four months.     

Multicriteria dynamic scheduling by swapping of dispatching rules

For most shop floors, consideration of more than one criterion would be likely to provide more realistic scheduling of a given set of jobs. The present paper considers this aspect of scheduling and uses an algorithm proposed by the authors in their previous work for implementing several criteria simultaneously in a shop of dynamic nature. The algorithm considers several dispatching rules simultaneously for selecting a job for processing and continuously monitors the attained values of performance measures. The selection of dispatching rules is made by identifying the worst performing criterion. A rule that can improve system performance for the worst-performing criterion is selected to dispatch the part under consideration. In this paper, several case studies have been attempted to evaluate the efficiency of the algorithm. The results of the taken case studies indicate that in a dynamic system the system performance improves by changing the dispatching rules corresponding to the worst-performance criterion at the appropriate deterioration in the performance measures.     

Transient-enhanced diffusion in shallow-junction formation

Shallow junctions are formed in crystalline Si by low-energy ion implantation of B⁺, P⁺, or As⁺ species accompanied by electrical activation of dopants by rapid thermal annealing and the special case of spike annealing. Diffusion depths were determined by secondary ion-mass spectroscopy (SIMS). Electrical activation was characterized by sheet resistance, Hall coefficient, and reverse-bias diode-leakage measurements. The B⁺ and P⁺ species exhibit transient-enhanced diffusion (TED) caused by transient excess populations of Si interstitials. The electrically activated fraction of implanted dopants depends mainly on the temperature for B⁺ species, while for P⁺ species, it depends on both temperature and P⁺ dose. The relatively small amount of diffusion associated with As⁺ implants is favorable for shallow-junction formation with spike annealing.     

Effects of exercise-induced oxidative stress on nitric oxide release and antioxidant activity

This study shows that acute exercise in healthy subjects is a modest oxidative stress, which may be related to an increase in antioxidant activity and down-regulation of nitric oxide formation.