Dynamic compressibility,release adiabats,and the equation of state of stilbene at high energy densities

The shock adiabat of porous stilbene (1,2-diphenylethylene) up to the pressure P = 41 GPa and the dynamic compressibility of this material in reflected shock waves up to 77 GPa are studied experimentally. The run of the expansion isentropes of stilbene down to 0.1 GPa is determined. The experimental findings are used to construct a semi-empiric equation of state of stilbene for a wide range of high-energy states.     

Train Times, Irish Whiskey, Bad Weather, Potage and Poldhu

Guglielmo Marconi and the events leading up to the first transatlantic radio message by R W Simons, Marconi researcher, 1943–1986     

Guiding, focusing, and cooling of atoms in a strong dipole potential

01 ^* (doughnut) modes for atomic beam manipulation. A slow atomic beam is guided over up to 0.3 m and focused down to 6.5 μm radius. The doughnut mode is used as a strong mesoscopic dipole potential with vibrational level spacings up to the photon recoil energy. Polarization gradient cooling in this system generates a bimodal momentum distribution with a narrow component momentum width of 4 ?k. Received: 26 June 1998     

Optical absorption coefficient of nickel,palladium platinum and copper,silver, gold between 20 and 120 eV

Electron-energy loss spectra recorded up to 120 eV are used to compute the complex dielectric constant and then the optical absorption coefficient.     

原子吸收光谱法测定桃叶中K,Mg,Sr,Fe,Cu,Mn和Zn等元素

本文采用桃叶作标准样品，讨论了湿法消化法与炭化－灰化法两种样品处理方法对测定结果的影响及方法操作效果比较，并进一步讨论了温度对炭化－灰化法的影响情况。由此建立起该法的适宜条件。在此条件下，用原子吸收光谱法测定桃叶及冷杉树枯枝、叶中多种元素。其精密度和准确度均能满足测定要求。     

Coassembly of Gold Nanoclusters with Nucleic Acids: Sensing,Bioimaging, and Gene Transfection

Assemblies of biopolymers and nanomaterials have become a powerful tool to build up new architectures with growing application potential. Herein, novel peptide‐stabilized fluorescent gold nanoclusters, K4‐AuNCs, are utilized as building blocks to investigate their coassembly with nucleic acids. K4‐AuNCs possess ultrasmall size (1.8 nm), red fluorescence emission, and positively charged surfaces, which are able to coassemble with DNA or RNA strands through electrostatic interactions to form pitaya‐like hybrid nanoparticles ranging from 30 to 80 nm, accompanied by an up to 3.5‐fold fluorescence enhancement. The coassembly also forms intracellularly, rendering K4‐AuNCs an attractive dye for specific in vivo nucleic acid staining, due to their higher photostability than commercial fluorescent probes such as SYTO 9. This work also demonstrates that the coassembly of K4‐AuNCs with nucleic acids can be applied to gene transfection and to build up a sensing platform to detect DNase/RNase activity or to screen their inhibitors. The new strategy greatly extends the application range of gold nanoclusters into the development of new nucleic acid detection methods and novel hybrid materials.     

Radio-photoluminescence of highly irradiated Lif:Mg,Ti and Lif:Mg,Cu,P detectors

The radio-photoluminescent (RPL) characteristics of LiF:Mg,Ti (MTS) and LiF:Mg,Cu,P (MCP) thermoluminescent detectors, routinely used in radiation protection dosimetry, were investigated after irradiation with ultra-high electron doses ranging up to 1 MGy. The photoluminescence of both types of LiF detectors was stimulated by a blue light (460 nm) and measured within a spectral window around 530 nm. The RPL dose response was found to be linear up to 50 kGy and sublinear in the range of 50 kGy to 1 MGy for MCP detectors and linear up to 3 kGy and next sublinear in the range from 5 kGy to 1 MGy for MTS detectors. For both type of LiF detectors RPL signal is saturated for doses higher than 100 kGy. The observed differences between MCP and MTS may suggest, that the RPL effect in LiF is not entirely governed by intrinsic defects (F₂ and F₃⁺ centers), but dopants may also have a significant influence. Due to the non-destructive character of the RPL measurement, it is suggested to apply combined RPL/TL readouts, what should improve accuracy of high-dose dosimetry.     

High-Spin States of Yrast Bands in Even Pu,Cm, Fm,and No Isotopes

Physics of Atomic Nuclei - The experimental energies of yrast-band states are known up to the spin of $$32^{+}$$ for some Pu, Cm, Fm, and No isotopes—in particular, for $${}^{248}$$ Cm. Their...     

Next-to-leading-order results for five, six, and seven jets in electron-positron annihilation

We present next-to-leading order corrections in the leading color approximation for jet rates in electron-positron annihilation up to seven jets. The results for the two-, three-, and four-jet rates agree with known results. The NLO jet rates have been known previously only up to five jets. The results for the six- and seven-jet rate are new. The results are obtained by a new and efficient method based on subtraction and numerical integration.     

Wide-bandwidth, tunable, multiple-pulse-width optical delays using slow light in cesium vapor

We demonstrate an all-optical delay line in hot cesium vapor that tunably delays 275 ps input pulses up to 6.8 ns and 740 input ps pulses up to 59 ns (group index of approximately 200) with little pulse distortion. The delay is made tunable with a fast reconfiguration time (hundreds of ns) by optically pumping out of the atomic ground states.     

Crystal growth and surface morphology of Pb,Bi, Sr,Ca, Cu,O, high T c superconductors

Two types of Pb, Bi, Sr, Ca, Cu, O superconducting single crystals: plate with a flat surface and bulk mica-like were successfully grown by a slow cooling method. As-grown crystal dimensions up to 1 cm² have been obtained. Magnetization and resistivity measurements indicate that the as-grown single crystals have a superconducting transition temperature at 85–90 K. Surface morphology observations by means of differential interference contrast microscope (DICM) and scanning tunneling microscope (STM) are reported.     

The measurement of the magnetic susceptibility of some elements (Fe,Co, Ni,Ge, Sn,Te) in the liquid state

A magnetic balance was used for measuring the susceptibility of metals and alloys, in an atmosphere of purified argon, up to 1800°c.

Comparison of the susceptibilities of liquid Fe, Co and Ni gives information on the liquid state. The changes in the susceptibilities of Ge, Sn and Te on melting are typical of semi-metallic elements and semiconductors, but their behaviour differs according to the degree of symmetry in the solid state.     

Generation of powerful,superbroad-band,subnanosecond electromagnetic pulses

The excitation of superbroad-band TEM antennas with a high-voltage subnanosecond modulator permitting a pulse-repetition frequency of up to 100 Hz is experimentally investigated. The modulator consists of a RADAN-303B nanosecond driver and a pulse amplifier based on gas discharges. The instrument generates unipolar and bipolar pulses of tunable length and amplitude. The amplitude and power of the pulses sent to the antenna reach 100 kV and 200 MW. Data are obtained on the stability of the parameters of the subnanosecond modulator pulses. Information is given on the electrical strength of the air insulation in the matching interval between the modulator and the antenna. The superbroad-band pulses emitted are recorded at distances of up to 25 m. The characteristics of the instrument permit the spatial resolution of reflections from conducting objects with a shape-inhomogeneity scale of no more than 25 cm. Emitters with increased directionality in the E or H (E and H) planes based on two (four) TEM antenna supplied with split modulator pulses are investigated. In-phase and antiphase antenna configurations are considered. Institute of Electrophysics, Ural Branch, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 119–127, December, 1996.     

Calculated equation of state of al, cu, ta, mo, and W to 1000 GPa

Calculated Hugoniots and 293-K isotherms at pressures up to 1 TPa (10 Mbar) for the five reference metals Al, Cu, Ta, Mo, and W are reported using the classical mean-field approach where both the cold and the thermal parts of the Helmholtz free energy are derived entirely from the 0-K total energies and electronic density of states calculated with the full-potential linearized augmented plane wave method within the generalized gradient approximation to exchange correlational functional. Our approach permits efficient computation and invokes no empirical parameters. Both the experimental Hugoniots and 293-K isotherms are reproduced excellently.     

The transport of slow ions in gases: Experiment, theory, and applications

This review is concerned with the two most important transport phenomena in involving slow ions in gases, namely their drift and diffusion in an externally applied electric field. The energy range of interest extends from thermal values at low temperatures up to about 10 eV. The transport phenomena are first discussed in physical terms, and experimental techniques for measuring ionic drift velocities and diffusion coefficients are then described. Brief coverage is given to ionic transport theory up to the time of Wannier's landmark contributions in 1951–1952; later theoretical developments are treated in more detail. Special emphasis is placed on aspects of modern theory that permit the determination of interaction potentials and collision frequencies for momentum transfer from experimental transport data. The review ends with a discussion of several applications of transport data to ionospheric problems.     

High-dose high-temperature emission of LiF:Mg,Cu,P: Thermally and radiation induced loss & recovery of its sensitivity

Highly sensitive LiF:Mg,Cu,P (MCP) detectors enable measurements of radiation doses from tens of nanograys up to a few kilograys, where the saturation of the signal of the main dosimetric peak occurs. Thanks to the recently observed high-dose high-temperature emission of MCP detectors heated to temperatures up to 600 °C after exposures to radiation doses ranging from 1 kGy to 1 MGy, a new method of thermoluminescent measurement of radiation doses has been recently developed at the Institute of Nuclear Physics (IFJ). This method can measure doses ranging from micrograys up to a megagray. So far, high dose measurements were performed on fresh MCP samples and each detector was used only once, because as a result of these measurements, the detectors lose their sensitivity to a large extent. In this study, a specific thermal treatment intended to fully restore the loss of MCPs TL sensitivity was sought. We have investigated several annealing procedures, applying different temperatures (from 400 °C up to 700 °C) for different periods of time (10–30 min) in argon atmosphere. In this way we were able to recover MCP sensitivity fully, allowing for reuse of the samples after high-dose irradiation and high-temperature measurement.     

Multicomponent photorefractive cnoidal waves: stability, localization, and soliton asymptotics

An algorithm of building up a different class of stable self-consistent multicomponent periodical solutions of the nonlinear Schr?dinger equation--multicomponent cnoidal waves--has been formulated by the example of a nonlinear wave propagating through a photorefractive crystal with a drift nonlinear response. Exact analytical expressions, describing distribution of light field in the components, have been obtained for solutions, which include up to three mutually incoherent components. It has been shown that such cnoidal waves are stable and their spatial structure is robust to collisions with the same cnoidal waves and to stochastic perturbations of the components' intensity distributions in a sufficiently wide range of changing spatial period.     

High-repetition-rate, high-average-power, diode-pumped 2.94-microm Er:YAG laser

We have demonstrated more than 3 W of average output power from a 2.94-mu;m quasi-cw diode-pumped total internal reflection (TIR) Er:YAG laser operating at 100 Hz with a 4% duty cycle. Moreover, repetition rates of up to 600 Hz at more than 1.2-W output power have been achieved. The cavity consists of a plane-mirror resonator of 40-mm length and uses three of five TIR regions within the laser crystal as pump facets to efficiently couple the pump energy into the resonant laser mode. Differential efficiencies of up to 18.3% have been achieved at an optimum pump pulse width in the range of 300 micros .     

Influence of the film thickness and additional elements (Al,O, and N) on the properties of FeCo film structures

The magnetic properties and domain structure of FeCoAlON thin films with thicknesses varying from 55 to 550 nm have been studied, and conditions favoring preparation of FeCoAlON films with uniaxial anisotropy in the direction normal to the film plane, which is required for designing “perpendicular” super-high-density information recording, have been established. In FeCoAlON films with a thickness up to 300 nm, the domain structure consists of cross-linked domain walls, because strong demagnetizing field suppresses formation of stripe domains. After the film thickness has reached 320 nm, cross-linked domain walls transform into stripe domains, with uniaxial anisotropy in the film plane disappearing, to become replaced by uniaxial anisotropy in the direction normal to the film plane, which can be assigned to magnetoelastic stresses induced by nitrogen atoms filling up interstitial space in the (110) plane. A further increase in the film thickness (up to 550 nm) leads to a rotational anisotropy due to the increase of nitrogen concentration in interstitials and the increase of magnetoelastic stresses.     

100-W average-power, high-energy nanosecond fiber amplifier

We report on the fiber-based amplification of a Q-switched Nd:YAG thin-disk laser. At repetition rates between 3 and 50 kHz output powers up to 100 W are generated. Pulse energies up to 4 mJ, with diffraction-limited beam quality, are generated in a 30-μm Yb-doped large-mode-area fiber, furthermore pulse energies up to 8 mJ are achieved from a multimode fiber amplifier. Received: 8 May 2002 / Revised version: 10 July 2002 / Published online: 25 October 2002 RID="*" ID="*"Corresponding author. Fax: +49-3641/65-7680, E-mail: Jens.Limpert@uni-jena.de