The room-temperature (300 K), pulsed mode operation of a GaAs-based quantum-cascade laser is presented. This has been achieved by the use GaAs/Al0.45Ga0.55As heterostructure which offers maximum Γ–Γ band offset (390 meV) for this material system without inducing presence indirect barrier states. Thus, better electron confinement achieved, countering loss injection efficiency with temperature. These devices show ∼100 K increase in operating temperature respect to equivalent designs using an...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReversible Fullerene Electrochemistry: Correlation with the HOMO-LUMO Energy Difference for C60, C70, C76, C78, and C84Yifan Yang, Francisco Arias, Luis Echegoyen, L. P. Felipe Chibante, Scott Flanagan, Andrew Robertson, Lon J. WilsonCite this: Am. Chem. Soc. 1995, 117, 29, 7801–7804Publication Date (Print):July 1, 1995Publication History Published online1 May 2002Published inissue 1 July...

Abstract Modeling forest change effects on snow is critical to resource management. However, many models either do not appropriately model canopy structure or cannot represent fine‐scale changes in following a disturbance. We applied 1 m 2 resolution energy budget snowpack at forested site New Mexico, USA, affected by wildfire, using input data from lidar prefire and postfire conditions. Both scenarios were forced with 37 years of equivalent meteorology simulate the effect fire‐mediated...

The author remarks that in the seventh volume of Cambridge Philosophical Transactions, Mr. Earnshaw has a paper on Mathematical Theory Waves Translation, and objection to theory therein given been pointed out by Professor Stokes Report British Association, namely, it requires mathematically sudden generation destruction motion. Previously his having an opportunity reading s he had considered subject manner entirely different (Phil. Mag. Dec. 1850, March 1851). analysis then employed was not...

We discuss recent research on synchronously pumped optical parametric oscillators, outlining some advantages that this technique has over Q-switched pulsed and cw modes of operation. also describe devices use potassium titanyl phosphate lithium triborate with pump lasers based second-harmonic generation the 1047-nm transition in Nd:YLF. Specific emphasis is placed all-solid-state synchronous pumping oscillators ability to achieve high efficiencies relatively low average powers. Both doubly...

Wires of platinum and tungsten 4-10 μm in diameter were used. They placed along the axis a coaxial cylinder. When wire was charged positively with respect to cylinder any gases ethylene, water, oxygen, nitrogen, nitrous oxide, ammonia, carbon monoxide hydrogen present, current observed, voltage between less than 20 kv. The directly proportional gas pressure except water ammonia. It appeared be due field ionization at surface wire. Currents exceeding 10-7 A obtained wires 2 cm long. Field...

We report on an optical parametric oscillator (OPO) that is synchronously pumped directly by a diode laser. This laser actively mode-locked master-oscillator power-amplifier system produces 20-ps pulses at 927 nm with repetition rate of 2.5 GHz and average power 0.9 W. The OPO, which singly resonant device based periodically poled lithium niobate, generates 7.8-ps pulses. OPO threshold 300 mW pump power, the maximum idler output 78 wavelength 2100 nm. By changing crystal temperature we can...

ABSTRACT A liquid phosphine oxide has been developed with a phosphoryl concentration of 2.3M, twice the maximum that can be reached in TOPO solvents at 50°C. Distribution coefficients are increased by 2m where m relates to mols extracting complex. The value is 1.6 for phenol, 1.0 acetic acid and 0.9 ethanol. Kinetics unchanged. Costs phenol new extractant isopropyl ether compared. Extraction coefficient separation factor ethanol compared other potential extractants.

Non-equilibrium stimulation of superfluidity in trapped Fermi gases is discussed by analogy to the work Eliashberg [G. M. Eliashberg, "Nonequilibrium Superconductivity," edited D. N. Langenberg and A. I. Larkin (North-Holland, New York, 1986)] on microwave enhancement superconductivity. Optical excitation fermions balanced heat loss due thermal contact with a boson bath and/or evaporative cooling enables stationary non-equilibrium states exist. Such state manifests as shift quasiparticle...

Field-ionisation mass spectra have been measured for a number of compounds. The sharp edge razor blade was used producing the strong electric field. Usually spectrum is simple with parent ion predominating and only slight formation fragment ions. Ions heavier than are sometimes formed by addition to proton or hydrated proton. ease ionisation various compounds can be correlated in two ways their potentials.The macroscopic field at an idealised calculated when above slotted plane. A similar...

Thermal fluctuations tend to destroy long-range phase correlations. Consequently, bosons in a lattice will undergo transition from phase-coherent superfluid as the temperature rises. Contrary common intuition, however, we show that nonequilibrium driving can be used reverse this thermal decoherence. This is possible because energy distribution at equilibrium rarely optimal for manifestation of given quantum property. We demonstrate Bose-Hubbard model by calculating spatial correlation...

Synthesizing binational data to characterize shared water resources is critical informing management. This work uses hydrogeology and resource in the Mesilla/Conejos-Médanos Basin (Basin) describe hydrologic conceptual model identify potential research that could help inform sustainable The aquifer primarily composed of continuous basin-fill Santa Fe Group sediments, allowing for transboundary throughflow. Groundwater flow, however, may be partially or fully restricted by intrabasin uplifts...

The kinetics of very fast dissociations positive ions can be determined by field ionization mass spectrometry using a sharp edge as source ions. broadening fragment peaks in spectrum was studied, and mainly due, favourable cases, to the time required for parent ion dissociate. Broadening due other causes removed from an observed peak deconvolution procedure before kinetic analysis carried out. knowledge potential distribution found b y conformal transformations. Dissociations occurring...

The Sebaou river valley (SRV) is located in the northern Tell region of Algeria, and a significant source ground surface waters because its geographical context within Algerian region. water resources from study area are important for both local people environmental scientists since undergoing industrial development. Therefore quantitative qualitative groundwater can help us to establish current physico-chemical variables resources, allowing comparisons with future studies. In this we...

A broadly tunable picosecond singly resonant optical parametric oscillator based on a Brewster-angled crystal of lithium triborate in ring cavity is described. The synchronously pumped by an all-solid-state frequency-doubled additive-pulse mode-locked Nd:YLF laser diodes. Continuous noncritically phase-matched tuning demonstrated from 839 to 1392 nm use one set optics. has threshold 47 mW average pump power and, with depletion 70%, can deliver output as high 88 mW.