A newly developed method is presented for measuring heat capacities on small samples, particularly where thermal isolation is not sufficient for the use of the traditional semiadiabatic heat-pulse technique. This "hybrid technique" is a modification of this heat-pulse method in case the temperature drift of the sample after the heat pulse is not linear but exponential. Deliberate extrapolations...

Femtosecond laser ablation of silicon in air was studied and compared with nanosecond laser ablation at ultraviolet wavelength (266 nm). Laser ablation efficiency was studied by measuring crater depth as a function of pulse number. For the same number of laser pulses, the fs-ablated crater was about two times deeper than the ns-crater. The temperature and electron number density of the pulsed l...

We report the design, growth, fabrication, and characterization of GaAs-based high-speed p – i – n photodiodes operating at 1.55 mm. A low-temperature-grown GaAs ~LT-GaAs! layer was used as the absorption layer and the photoresponse was selectively enhanced at 1.55 mm using a resonant-cavity-detector structure. The bottom mirror of the resonant cavity was formed by a highly reflecting 15-pair G...

A novel fibre optic sensing system with a high time resolution of less than 0.04 ps based on an optical pulse correlation measurement mechanism and differential detection technique is investigated. The optical pulse correlation state corresponding to time drift in fibre optic transmission lines is detected by SHG. The results of temperature and strain sensing experiments demonstrate an excellen...

We demonstrate highly efficient pulse stretching in Er(3+)-doped femtosecond mode-locked fiber lasers by tailoring cavity dispersion using an intracavity short-pass edge filter. The cavity dispersion is preset at around zero to obtain the shortest pulsewidth. When the cutoff wavelength of the short-pass edge filter is thermo-optically tuned to overlap the constituting spectral components of mod...

For an experiment to study neutron radiative beta-decay, we operated large area avalanche photodiodes (APDs) near liquid nitrogen temperature to detect x rays with energies between 0.2 keV and 20 keV. Whereas there are numerous reports of x ray spectrometry using APDs at energies above 1 keV, operation near liquid nitrogen temperature allowed us to reach a nominal threshold of 0.1 keV. However,...

-Detailed analysis of the effects of temperature on the circadian rhythm of eclosion in Drosophila pseudoobscura adults yielded results similar to those in similar studies of other poikilotherms : although the period, T, of the free-running oscillation varies little with different constant temperatures, it can be phase shifted by changes (steps and pulses) and entrained by temperature cycles. T...

arterial pulse measurement is one of the most important methods for evaluation of healthy conditions. in traditional iranian medicine (tim), physician may detect radial pulse by holding four fingers on the patient’s wrist. by using this method, under standard condition, the detected pulses are subjective and erroneous, in case of weak and/or abnormal pulses, the ambiguity of diagnosis may rise....