... the first of these, high densities (> 10(exp ... The data suggest that a population inversion on ... was achieved, but the inversion density was insufficient ...

The conditions associated with a population inversion of the He I levels with principal quantum numbers 4 and 3 are studied in the supersonic expansion of helium plasma from circular and plane nozzles into a low-pressure region. In an axisymmetric jet the population inversion arises at some finite distance from the ...

The feasibility of achieving population inversion in a laser by means of chemical depopulation of the lower working state is considered. Calculations for the case of HgH are made. (AIP)

... is necessary to achieve population inversion, a long upper-state lifetime is also ... in a small oscillator strength, and in a broad emission linewidth due ...

A review is given of theoretical and experimental investigations concerned with the feasibility of light amplification in the far ultraviolet (3--50 nm) due to transitions in multiply charged ions. An analysis is made of the most advanced population inversion methods. Experiments in which population inversion was ...

We discuss an opportunity to achieve lasing without inversion in three-level cascade scheme using an effective unidirectional pumping via bidirectional incoherent pump. Analytical solution to the population and the coherence are obtained in the steady-state regime. With a proper choice of the parameters, a possibility for lasing ...

The possibility of achieving lasing action at 14 and 16 ..mu.. in a CO/sub 2/ laser is considered. The population inversion is computed as functions of temperature and pressure for a system with subcritical mixing of gas flows not in thermal equilibrium.(AIP)

An analysis is made of the vibrational kinetics in a CO/sub 2/--N/sub 2/ mixture with hydrogen halide admixtures as the mixture expands through a supersonic nozzle. The effect of these admixtures on the population inversion in CO/sub 2/ is studied. It is shown that the inversion achieved is comparable to that ...

... that meaningful super resolution is achievable with ... PROCESSING, *HIGH RESOLUTION, *INVERSE PROBLEMS, REPRINTS, FOURIER ...

... that meaningful superresolution is achievable with ... PROCESSING, *HIGH RESOLUTION, *INVERSE PROBLEMS, REPRINTS, FOURIER ...

Impurities are necessary to achieve considerable CW laser action in CO2 since in pure CO2 the disintegration of the lower laser level is too slow to maintain a substantial population inversion. The dissociation product CO, provided by the discharge itself...

... Ho:YLF, 2.06 micronmeter laser) to directly populate the upper laser level which achieves inversion before non-radiative decay depletes the initial ...

We have theoretically determined and experimentally confirmed that polychromatic multiphoton coherent excitation can be used to most efficiently achieve a selective total population inversion in a multilevel system. These results suggest a solution to the problem of using mesospheric sodium as a guidestar.

A method of inverse sampling of controls in a matched case-control study is described in which, for each case, controls are sampled until a discordant set is achieved. For a binary exposure, inverse sampling is used to determine the number of controls for each case. When most individuals in a population have the ...

... Title : DETERMINATION OF POPULATION INVERSION AND LOSS IN A RUBY LASER BELOW ROOM TEMPERATURE (130-260K). ...

... Accession Number : AD0774198. Title : Backward Population Projection by a Generalized Inverse. Descriptive Note : Technical summary rept.,. ...

We study theoretically the population inversion in intrinsic graphene under optical pulse excitation at room temperature. We develop the theoretical model of carrier relaxation dynamics based on the rate equations derived from the quasi-classical Boltzmann equation. We take into account the energy relaxation and recombination by the intra and interband ...

The possibility of constructing a soft x-ray laser by utilizing coincidence between resonance lines of multiply charged ions has been amply studied. Here we report a new scheme utilizing near coincidence between resonance line and intercombination line, by which a population inversion of the n = 5--4 transition of hydrogen-like NaXI ions has been ...

An anti-Stokes Raman laser is disclosed which is tunable over a range of 10-70 cm-/sup 1/. An alkali halide is used as the lasing medium and a metastable halide population inversion is created with respect to the ground state of the halide by selective photodissociation of the alkali halide. A pump laser is then employed to move the ...

Exact expressions are obtained for transient populations of a two-level ion subjected to strong optical and electrostatic fields. The conditions under which the population inversion takes place are identified.

The collisional-radiative model is applied to a recombining hydrogen plasma in order to investigate the plasma condition in which the population inversion between the energy levels of hydrogen can be generated. The population inversion is expected in a pl...

Conditions for population inversion are discussed for hydrogen-like ions by means of the collisional-radiative model. Population inversion becomes more noticeable with decreasing electron temperature. For a fixed electron temperature, there are an upper b...

Above-threshold ionization (ATI) ionization by linearly polarized light has been proposed by several authors as a means of driving recombination lasers in the soft x-ray spectral region. The pump radiation generates a cold electron plasma with ions in a single ionization stage, which is an ideal starting condition for strong recombination. Population ...

Above-threshold ionization (ATI) ionization by linearly polarized light has been proposed by several authors as a means of driving recombination lasers in the soft x-ray spectral region. The pump radiation generates a cold electron plasma with ions in a single ionization stage, which is an ideal starting condition for strong recombination. Population ...

The possibility of obtaining energy-level population inversion by heterogeneous mixing of chemically reacting flows is analyzed.

... TITLE: Far Infrared Emission and Possibility of Population Inversion of Hot Holes in MQW TnGaAs/GaAs Heterostructures Under Real Space ...

We consider some possible mechanisms for producing gain in the 10 nm spectral region. They involve the creation of a population inversion in a confined plasma column by selective excitation of multicharged ions via absorption of many (>10) ultraviolet photons. Specific treatment is made of Kr-like ions pumped by a KrF excimer laser. 27 refs., 5 figs.

A stimulated emission of the 558.9, 579.9, 1062, and 1074 nm lines in the spectrum of Sn II and of the 657.9 nm line in the spectrum of Sn I was achieved. The ion laser transitions were pumped by the recombination of Sn$sup 2+$ and by the charge exchange in collisions of helium or neon ions with tin atoms.

In direct nuclear pumped lasers the high energy fission fragments generate a large number of secondary electrons and these electrons are mainly responsible for achieving the population inversion in the lasing media. Laboratory measurements concerned with these electron impact processes are summarized and new results are presented on ...

The development of direct nuclear pumped lasers is reviewed. Theoretical and experimental investigations of various methods of converting the energy of nuclear fission fragments to laser power are summarized. The development of direct nuclear pumped lasers was achieved. The basic processes involved in the production of a plasma by nuclear radiation were studied. Significant ...

Implementation of quantum logical gates for multilevel systems is demonstrated through decoherence control under the quantum adiabatic method using simple phase modulated laser pulses. We make use of selective population inversion and Hamiltonian evolution with time to achieve such goals robustly instead of the standard unitary ...

Various conditions necessary for achieving population inversion and gain in the x-ray spectral region by matched-line photon pumping in plasmas are discussed, and some promising test cases are listed. For representative pump lines, measured intensities at the saturation level are reported. For a most promising sodium/neon combination ...

A new sampling procedure is introduced for estimating a population proportion. The procedure combines the ideas of inverse binomial sampling and Bernoulli sampling. An unbiased estimator is given with its variance. The procedure can be viewed as a generalization of inverse binomial sampling.

... The experimental results of electron temperature and population densities are discussed by simple numerical analysis which we previously ...

"temperature" is inversely proportional to population diversity #12;Boltzman MAs: acceptance criteria Assuming

Genetic algorithms (GAs), global optimization methods that mimic Darwinian evolution are well suited to the nonlinear inverse problems of geophysics. A standard genetic algorithm selects the best or ''fittest'' models from a ''population'' and then applies operators such as crossover ...

The possibility of achieving laser action in the sputtered metallic vapor of a hollow cathode glow discharge was investigated. Intensity measurements are carried out on the spectral lines emitted by the vapor in the cathode region of copper and iron hollow cathode tubes. The measurements are analyzed using a graphical technique designed for identifying inverted excited state ...

This paper assumes that cortical circuits have evolved to enable inference about the causes of sensory input received by the brain. This provides a principled specification of what neural circuits have to achieve. Here, we attempt to address how the brain makes inferences by casting inference as an optimisation problem. We look at how the ensuing recognition dynamics could be ...

AbstractThis paper assumes that cortical circuits have evolved to enable inference about the causes of sensory input received by the brain. This provides a principled specification of what neural circuits have to achieve. Here, we attempt to address how the brain makes inferences by casting inference as an optimisation problem. We look at how the ensuing recognition dynamics ...

The influence of the population of barium atoms on barium cloud ionization in the upper atmosphere is investigated. It is shown that the experimental values of the effective time for barium cloud ionization is determined by the metastable 3D states' inversion population.

... P = 0.680). Home range size in the control area suggested an inverse relationship with population density but these results had ... to our prediction, we did not find an inverse relationship between popul...

We propose an inverse idea of controlling the evolution of the population inversion by a time-dependent coupling between the cavity field and a two-level system described through the Jaynes-Cummings model. We demonstrate the detailed procedure by obtaining the population evolution taking the non-sinusoidal form, ...

This paper describes a combined theoretical and experimental approach to understanding the capillary spark discharge with specific application to use as a soft x-ray or extreme ultraviolet laser source. Atomic physics calculations have identified several potential laser lines in a collisionally pumped neon-like or nickel-like plasma, and magnetohydrodynamic (MHD) modeling has shown that a ...

Single-mode, strip-loaded silicon-rich silicon nitride (SRSN) waveguide with 11 at.% excess Si and 1.7�10(20) cm(-3) Er was fabricated and characterized. By using a 350 nm thick SRSN:Er core layer and a 850 nm wide SiO2 strip, a high core-mode overlap of 0.85 and low transmission loss of 2.9 dB/cm is achieved. Population inversion of ...

The construction of a feed-forward controller frequently requires the estimation of an inverse function. Two possible methods to achieve this are: (i) learning the best estimated inverse (BEI), a method that is sometimes referred to as direct inverse learning and (ii) learning the inverse of ...

Apoptosis is known as a major achievement of biological world evolution aimed at eliminating "genetic waste," transformed or obsolete cells, and hence at controlling neoplastic processes. At the same time, clinical data point to an inverse effect. Thorough fundamental studies at the levels of light and electron microscopy allowed us to reveal several ...

We explore the relaxation of photoexcited graphene by solving a transient Boltzmann transport equation with electron-phonon (e-ph) and electron-electron (e-e) scattering. Simulations show that when the excited carriers are relaxed by e-ph scattering only, a population inversion can be achieved at energies determined by the photon ...

We propose a method to achieve amplification without population inversion by anisotropic molecules whose orientation by an external electric field is state-dependent. It is based on decoupling of the lower-state molecules from the resonant light while the excited ones remain emitting. The suitable class of molecules is discussed, the ...

We study theoretically the conditions under which optical bistability is achievable in a two-subband system in a semiconductor quantum well. We consider the interaction of the two-subband system with a continuous wave electromagnetic field, which induces intersubband transitions. For the description of the system dynamics we use the effective nonlinear density matrix ...

Recombining helium-neon plasmas are studied theoretically for free electron densities N/sub e/ = 10/sup 13/--10/sup 17/ cm/sup -3/, electron temperatures T/sub e/ = 0.05--0.50 eV, and heavy particle densities N<10/sup 18/ cm/sup -3/. The populations of the helium and neon levels are calculated in the steady sink approximation. It is shown that pure neon plasmas are not well ...

A model expample has been developed which slows that the the interaction of an equilibrium (molecular) beam with a surface can under certain conditing produce significant nonequilibrium and population inversion in the rotational levels. (AIP)

The plasma condition is theoretically investigated for the population inversion between the first two excited states of hydrogen atoms in a recombining plasma. The rate equation including atom-atom collision terms is solved consistently with the optical e...

The plasma condition is theoretically investigated for population inversion between the first two excited states of hydrogen atoms in a recombining plasma. The rate equation including atom-atom collision terms is solved consistently with the optical escap...

Inversions in the populations of excited levels in hydrogen and HeII were observed in the FM-1 Spherator. The inversion increases strongly as the ratio of the decay time of the electron temperature to the decay time of the electron density was decreased. ...

The Leslie propulation projection matrix may be used to project forward in time the age distribution or age-sex distribution of a population. As it is a singular matrix, it does not have an inverse, and so it is not clear that there is a corresponding pro...

The achievement of anti-Stokes Raman-laser oscillation in atomic Se at 158.7 and 167.5 nm using pump-laser radiation at 199.5 and 254.8 nm is reported. The necessary population inversion between the (1)S(0) and lower (1)D(2) or (3)P states is achieved by photodissociation of COSe molecules with ArF-laser radiation. ...

We describe the characteristics of a cw HF chemical laser used for molecular-beam scattering studies. Unlike with most such lasers, a complete population inversion is achieved, resulting in /similar to/100 mW of single-line output even for some /ital R/-branch transitions. The laser emission shows a prominent Lamb dip and can ...

We consider some possible mechanisms for producing gain in the 10-nm spectral region. They involve the creation of a population inversion in a confined plasma column by selective excitation of multiply charged ions through absorption of many (>10) ultraviolet photons. Calculations of the energy-level structure of ions in the Kr isoelectronic sequence ...

The paper reports on a collisional-type laser in which population inversion is achieved through collisional cleaning of the lower working level. This scheme allows the use of long-lived or metastable states as the lower level, as a consequence of which the quantum efficiency of potential laser media can reach values of 20-50 percent, ...

This paper presents an assessment of the feasibility of using electrical pumping to achieve laser action in color centers in the alkali halides. We discuss mainly the self-trapped exciton in the alkali halides, which is a prime candidate for such a pumping scheme because it is known to produce strong electroluminescence. The theory of electrical contacts to insulating crystals ...

... population which is forbidden (by symmetry) to ... on the uppermost transition in the ... GROUND STATE, TRANSITIONS, INVERSION, INTERFERENCE ...

... a) elucidating the kinetics of chemical relaxation of ... The results for reaction (4) are consistent with 7 ... one takes into account that the flame kinetics ...

... levels of radio frequency and microwave ... Descriptors : *ABLATION, *CARBON, *EMISSION ... PRODUCTION, PULSES, RADIOFREQUENCY, SIDES ...

... systems which arise in the study of multiscale phenomena in diverse fields such as immunological population dynamics, viscoelasticity of polymers ...

... were found spectrographically. This reveals the possibility of making a gas-dynamic laser. (Author). Descriptors : (*PLASMA ...

Population inversion is observed between the field-independent ground hyperfine states of Rb-87 when

... Report Date : 31 MAR 1972. ... Models for obtaining population inversions are proposed in the case of mercuric halides, copper halides, and organic ...

... in the context of an inverse problem methodology and its use in illustrated with application to mosquitofish, Gambusia affinis, population in rice ...

... Demographic data indicates that the proportion of the American population older than 55 is projected to increase considerably through 2050. ...

... The chemical reaction between these reactants creates, directly, a vibrationally excited gaseous product with the requisite population inversion and ...

An investigation has been conducted to determine the feasibility of generating conditions favorable to population inversion, gain, and X-ray lasing in a two-component plasma consisting of sodium and neon. An intense laser beam is assumed incident on both sides of a Na/Ne slab target separated by a carbon thermal buffer. Temperature and density profiles of ...

Method and apparatus for inducing laser action in CO.sub.2 at a wavelength of 16 microns involving the transition between the 02.sup.0 0 and 01.sup.1 0 states. The population inversion between these two states is achieved by pumping to the 00.sup.0 1 level, suppressing the usual 10.6 micron transition to the 10.sup.0 0 level and ...

Most laser-induced femtosecond magnetism investigations are done in magnetic thin films. Nanostructured magnetic dots, with their reduced dimensionality, present new opportunities for spin manipulation. Here we predict that if a magnetic dot has a dipole-forbidden transition between the lowest occupied molecular orbital (LUMO) and the highest unoccupied molecular orbital (HOMO), but a ...

Certain aspects of the theory of a gasdynamic laser that uses a partial population inversion are examined. The effect of quasiresonant V--V exchange in the supersonic expansion of a binary mixture of an energy carrier and the working gas is examined in detail. The relation between ''freezing'' of the number of ...

An analysis is made of the physicochemical processes in the active medium and the role of xenon in the mechanism of population inversion in carbon monoxide lasers is discussed. It is concluded that the positive effect of the addition of xenon to the working mixture of a sealed CO laser is due to a reduction in the rate of plasma-chemical reactions, which ...

The collisional-radiative model is applied to a recombining hydrogen plasma in order to investigate the plasma condition in which the population inversion between the energy levels of hydrogen can be generated. The population inversion is expected in a plasma where the three body recombination has a large ...

Structural rearrangements, including copy-number alterations and inversions, are increasingly recognized as an important contributor to human genetic variation. Copy number variants are readily measured via array-based techniques like comparative genomic hybridization, but copy-neutral variants such as inversion polymorphisms remain difficult to identify ...

The steady-state distribution of the populations of the hyperfine sublevels of the ground state of alkali atoms is calculated for the case in which the atoms are subjected to a spectrally selective optical pumping on /sup 2/S/sub 1//sub ///sub 2/--/sup 2/P/sub 1/2,3/2/ transitions and a simultaneous pumping by microwave fields which are at resonance with transitions in the ...

Laser-produced plasmas have proved to be suitable media to achieve soft x-ray amplification and their study benefits directly from the advances in laser development for Inertial Confinement Fusion (ICF) research. In recent years the IR light (1.054 ..mu..m) from powerful Nd:Glass lasers has been frequency-tripled into UV light (0.351 ..mu..m) with conversion efficiencies ...

It is shown, following Shockley [Shockley, W. (1957) Proc. IRE 45, 279-290], that, when a population is engaged in tasks whose completion requires the successful conclusion of many independent subtasks, the distribution function for successes in the primary task is log normal. It is also shown that, when the dispersion of the log-normal distribution is large, the distribution ...

The wavelengths, the rates of processes, and the gains of spontaneous emission at the transitions of Pd-like ions from ErXXIII to ReXXX are calculated for the first time. The high quantum yield of amplified emission in these ions is possible at transitions in the spectral range from 10 to 16 nm. It is assumed that a plasma is produced due to the interaction of an ultrashort laser pulse with a beam ...

The conditions for population inversion of hydrogen atomic levels with principal quantum numbers n = 4 and 5 are investigated in the free expansion region of a supersonic hydrogen--argon plasma jet. Data are obtained on the degree of population inversion as a function of the stagnation enthalpy and the amount of ...

Crosshole radar tomography is often used in geological, hydrological and engineering investigations to map shallow subsurface electrical properties, viz. dielectric permittivity and electrical conductivity. These properties are closely linked to important hydrogeological parameters like salinity, water content, porosity and pore structure, clay content, and lithological variations. Common practice ...

This paper present the map of polytene chromosomes and inversion polymorphism of widely distributed Chironomidae species, Camptochironomus tentans, from the most western locality of Russia--Kaliningrad city. Chromosomes banding pattern is designated according to Beermann, 1955. Only one larva (2.9%) had a standard banding pattern, and karyotypes of the rest (97.1%) were ...

Reconfiguration of the flight control system is achieved using generic inputs and transformation matrices for single primary control surface failure. Pseudo-inverse is used to evaluate appropriate transformation matrices. Design is tested against non-line...

An ac power regulator was designed for loads with inverse resistance-temperature properties. It is equipped with an integrated-circuit, analog multiplier for power computation. Its output power accuracy, achieved by automatic zero correction of the multip...

The data presented here suggests that there is a small but finite probability of change toward neoplasia with each round of cell division due to chance error in replication and/or low level environmental carcinogens. When one clonogenic cell has accumulated changes sufficient in nature and number, overt neoplasia ensues. If this be true, it follows that the probability that one clonogenic cell in ...

Mouse t haplotypes are variant forms of chromosome 17 that exist at high frequencies in worldwide populations of several species of house mouse. They are known to differ from wild-type chromosomes with respect to two relative inversions referred to as proximal and distal. An untested assumption has been that these two inversions ...

In this paper, we analyze the condition for complete population inversion by a chirped pulse over a finite duration. The nonadiabatic transition probability is mapped in the two-dimensional parameter space of coupling strength and detuning amplitude. Asymptotic forms of the probability are derived by the interference of nonadiabatic transitions for ...

A numerical analysis is presented of several potential applications of adiabatic population inversion in atoms or molecules using pulsed lasers. A simple numerical method is demonstrated for evaluating adiabatic processes in multilevel systems for both swept-frequency and resonant, time-delayed pulses. Adiabatic inversion with ...

We report data that continue the studies of Dobzhansky and others on the frequencies of third-chromosome inversions in natural populations of Drosophila pseudoobscura in North America. The common gene arrangements continue to be present in frequencies similar to those described four decades ago, and the broad geographic patterns also remain unchanged. ...

... Title : The Human Terrain System: Achieving a Competitive Advantage Through Enhanced "Population-Centric" Knowledge Flows. ...

The inner-shell photo-ionization (ISPI) scheme requires photon energies at least high enough to photo-ionize the K-shell. {approx}286 eV, in the case of carbon. As a consequence of the higher cross-section, the inner-shell are selectively knocked out, leaving a hole state 1s2s{sup 2}2p{sup 2} in the singly charged carbon ion. This generates a population ...

There is a growing appreciation that chromosome inversions affect rates of adaptation, speciation, and the evolution of sex chromosomes. Comparative genomic studies have identified many new paracentric inversion polymorphisms. Population models suggest that inversions can spread by reducing recombination between ...

Amplitude squeezing is calculated for multi-level closed-cycling atomic systems. These systems can last without atomic population inversion in any atomic bases. Maximum squeezing is obtained for the parameters in the region of lasing without inversion. A ...

Interferences of autoionizing lines may reduce or eliminate absorption of lower level atoms. Stimulated emission shows no such interferences, thereby allowing laser gain without population inversion.

Similarities in the energy-level structure of the sulfur hydride radical and the hydroxyl radical suggest that sulfur hydride in the interstellar medium might be detectable because of a population inversion or anti-inversion similar to that of the hydroxy...

A Comparison Between Geostatistical Inversion and Conventional Geostatistical Simulation Practices seismic cube is populated with realizations of acoustic impedance obtained using conventional sequential before being accepted as final realizations. To perform this test, the realizations of acoustic

The possibility of forming radiation by exploiting the gasdynamic characteristics of flows within laser cavities is investigated. The periodic compression which occurs in flows can serve as gaseous dielectric waveguides which single out electromagnetic oscillations localized in narrow zones of inverse population. A shock wave in a chemically reacting H2-F2 ...

A source of nanometer wavelength, transverse-polarized, sound waves based on stimulated emission of phonons in a semiconductor superlattice inside an acoustic cavity and pumped by a low-average power nanosecond pulsed laser is described. The experimental evidence for sound laser (saser) action in our device is a superlinear increase in emitted acoustic intensity and an increase in emission ...

We report the electrically pumped ultraviolet random lasing from ZnO nanorod arrays on Si. Metal-insulator-semiconductor structures in a form of Au/SiO(2)/ZnO-nanorod-array were fabricated on Si. Such devices exhibit random lasing when the Au electrode is applied with a sufficiently high positive voltage. In this context, in the region adjacent to SiO(2)/ZnO-nanorod-array interface, stimulated ...

Relative intensity fluctuations in single-mode class B lasers, i.e., a laser diode (LD) and a microchip Nd YVO(4) solid-state laser (SSL), were examined. Experimental observations revealed significant difference in the characteristics of the LD and the SSL. A stochastic laser model and the Fokker-Planck equation approach were used, and reduced moment equations were developed. A close agreement was ...

Relative intensity fluctuations in single-mode class B lasers, i.e., a laser diode (LD) and a microchip Nd:YVO4 solid-state laser (SSL), were examined. Experimental observations revealed significant difference in the characteristics of the LD and the SSL. A stochastic laser model and the Fokker-Planck equation approach were used, and reduced moment equations were developed. A close agreement was ...

The temperature dependence of the free-carrier concentration in germanium doped with the double acceptor Be has been investigated using the photo Hall-effect technique and found to be strongly temperature dependent when the residual shallow impurities are closely compensated. Close compensation of shallow levels was achieved by controlling the concentration of a ...

The authors report the results of nondegenerate optical pump-probe absorption experiments performed on GaN and InGAN thin films and quantum wells under the conditions of strong optical band to band excitation. The evolution of the band edge in these materials was monitored as the number of photoexcited free carriers was increased beyond that required to achieve ...

In this report a method for calculating nonequilibrium atomic physics parameters in hot plasmas is described. This type of calculation is necessary for accurate simulation of laser fusion target experiments, where, generally, outside the ablation surface the target is non-LTE. Another problem of interest in which non-LTE is important is in x-ray laser experiments. Here the whole process of ...

The roles of gaseous and quantum electronics in nuclear engineering, and consequently in nuclear engineering education, are growing at a significant rate. The nuclear engineering program of the University of Illinois currently has 10 students, out of a total graduate student enrollment of 90, specializing in these areas. Course work follows an interdisciplinary approach to supplement the ...

Excited states in Mg30 have been populated to ~6? and 5 MeV excitation energy with the C14(O18,2p) reaction. Firm spin assignments for states with J>2? have been made in this nucleus. The level scheme is compared to shell-model calculations using the Universal sd effective interaction and the Monte Carlo shell model method. Calculations employing a full sd model space fail ...

Many of the projected applications of x-ray lasers require high quality output radiation with properties such as short wavelength, high power, good focusability, short pulse, and high degree of coherence. We discuss the requirements of an x-ray laser for the application of holography of biological samples. We present ideas for achieving these properties. Given that ...

In a calculation of demonstrative type collective, laser-like behavior of low energy nuclear fusion reaction of deuterons in crystalline environment is investigated. It is found that the reported extra 4He production can be appropriately described with a model well known in quantum electronics in which the quantized boson (4He) field interacts with an ensemble of two-level systems in a crystal ...

2.79 [mu]m quasi-CW laser operation at room temperature was achieved from a YSGG:Cr:Er crystal. The output from the crystal, which was longitudinally pumped with a Ti:sapphire laser at 790 nm, was self-terminating. Under quasi-CW pumping, the length of the emitted pulses decreased exponentially with increasing pump power. The self-terminating behavior is explained by thermal ...

... and operate more effectively among foreign populations. ... knowledge of the population critical for ... Human Terrain System designed to create and ...

The high degree of axisymmetry achieved in these vortex ring experiments permits Abel inversion to yield the space- and time-varying mixture fraction field ...

... protocol is derived, based on which, we develop a low-complexity inverse-log scheduling algorithm that achieves near-optimal energy efficiency. ...

... the inability of the parasitoid to achieve satisfactory control. It has been suggested that an inverse pattern of parasitism may be the result of ... ...

... the acousto-optic crystal which is 170ns. ... the spot size of the pump is increased, the cavity volume achieving inversion increases ... mode cavities. ...

... Our new inverse optimality approach to robust nonlinear control avoids the need to solve the HJI equation, but still achieves the desirable ...

A spectroscopic diagnostic to measure impurity ion poloidal velocity profiles using charge exchange recombination spectroscopy has been installed on NSTX. Up-down symmetric viewing chords in the plane of the neutral beam are matched with similar symmetric views off the neutral beam to measure both active and background emission. Eight fast (f/1.8-f/2) camera lenses at four locations make up the ...

Measurements of ({sup 3}He,d) reactions can provide information on the proton widths of states that play a role in astrophysically important (p,{gamma}) reactions. We report on the first study of the ({sup 3}He,d) reaction in inverse kinematics with a {sup 56}Ni (T{sub 1/2}=6.1 d) ion beam. The Q-value resolution of {approx} keV achieved in this experiment ...

The possibility of extending the laser principle into the hard x-ray region above a few keV depends upon the ability of a pump to create the critical density of population inversion for which gain overcomes loss by absorption. Although this critical density decreases with the wavelength of the radiation to be stimulated, the power required to generate it ...

We consider the population inversion in a two-level system generated by a sub-one-cycle pulse excitation. Specifically, we explore the effect that the time derivative of the pulse envelope has on the Rabi dynamics. Our analysis is based on a combination of analytical, perturbative, and nonperturbative treatments and is complemented by numerical ...

Diets high in fruits and vegetables are generally believed protective against several chronic diseases. One suggested mechanism is a reduction in oxidative stress. The carotenoids, nutrients found in colored fruits and vegetables, possess antioxidant properties in vitro, but their role in humans is less well documented. The aim of this cross-sectional study was to explore the relationships between ...

Inversions in the population of excited levels in hydrogen and He II were observed in the FM-1 spherator. The inversion increases strongly as the ratio of the decay time of the electron temperature to the decay time of the electron density was decreased. Time-dependent numerical calculations of the populations were ...

Inversions in the populations of excited levels in hydrogen and HeII were observed in the FM-1 Spherator. The inversion increases strongly as the ratio of the decay time of the electron temperature to the decay time of the electron density was decreased. Time dependent numerical calculations of the populations were ...

Chromosomal inversions are ubiquitous in nature and of great significance for understanding adaptation and speciation. Inversions were the first markers used to investigate the genetic structure of natural populations, leading to the concept of coadapted gene complexes and theories concerning founder effects and genetic drift in small ...

We study the evolution of inversions that capture locally adapted alleles when two populations are exchanging migrants or hybridizing. By suppressing recombination between the loci, a new inversion can spread. Neither drift nor coadaptation between the alleles (epistasis) is needed, so this local adaptation mechanism may apply to a ...

This paper presents a methodology incorporating ultrasonic and eddy current data and NDE models to characterize pits in first and second layers. Approaches such as equivalent pit dimensions, approximate probe models, and iterative inversion schemes were designed to improve the reliability and speed of inverse methods for second layer pit characterization. ...

Control for the bracing strategy is being examined. It was concluded earlier that trajectory planning must be improved to best achieve the bracing motion. Very interesting results were achieved which enable the inverse dynamics of flexible arms to be calc...

We consider how externally coupled (e.g., dc-field-coupled) autoionizing states can be useful in producing gain without population inversion. The dc fields produce new absorption minima that enable one to obtain laser action in different frequency regions depending on the strength of the coupling. We calculate absorption and emission profiles assuming that ...

The collisional-radiative model for hydrogenlike ions is used to investigate the scaling of recombination at low temperatures in order to identify the necessary conditions of electron density and temperature, which will allow population inversion between the first excited state and the ground state to be developed. Numerical calculations show that at low ...

The collisional-radiative model for hydrogenlike ions is used to investigate the scaling of recombination at low temperatures in order to identify the necessary conditions of electron density and temperature, which will allow population inversion between the first excited state and the ground state to be developed. Numerical calculations show that at low ...

The relaxation of a recombining Cu-Cs plasma is considered for spherical expansion under vacuum. The system of differential equations describing the plasma parameters has been integrated by the Runge-Kutta method. Estimates have been made of the roles of atomic collisions in producing population inversion in the two-component plasma. It is shown that ...

The temporal dynamics of the populations of the 3s levels of neon and its dependence on the hydrogen impurity concentration was studied in the active medium of a neon-hydrogen plasma laser excited by a longitudinal discharge with preionization. The limits of existence of the inversion of the ? = 585.3 nm transition were determined and ...

We show that in a four-level atomic system with electromagnetically induced transparency, a coherent pump field can induce light amplification without or with population inversion. As the pump field intensity increases, the atomic system evolves from normal dispersion and amplification without population inversion ...