Thermal tuning On narrow linewidth fiber laser

Science.gov (United States)

Han, Peiqi; Liu, Tianshan; Gao, Xincun; Ren, Shiwei

2010-10-01

At present, people have been dedicated to high-speed and large-capacity optical fiber communication system. Studies have been shown that optical wavelength division multiplexing (WDM) technology is an effective means of communication to increase the channel capacity. Tunable lasers have very important applications in high-speed, largecapacity optical communications, and distributed sensing, it can provide narrow linewidth and tunable laser for highspeed optical communication. As the erbium-doped fiber amplifier has a large gain bandwidth, the erbium-doped fiber laser can be achieved lasing wavelength tunable by adding a tunable filter components, so tunable filter device is the key components in tunable fiber laser.At present, fiber laser wavelength is tuned by PZT, if thermal wavelength tuning is combined with PZT, a broader range of wavelength tuning is appearance . Erbium-doped fiber laser is used in the experiments,the main research is the physical characteristics of fiber grating temperature-dependent relationship and the fiber grating laser wavelength effects. It is found that the fiber laser wavelength changes continuously with temperature, tracking several temperature points observed the self-heterodyne spectrum and found that the changes in spectra of the 3dB bandwidth of less than 1kHz, and therefore the fiber laser with election-mode fiber Bragg grating shows excellent spectral properties and wavelength stability.

1.7  μm band narrow-linewidth tunable Raman fiber lasers pumped by spectrum-sliced amplified spontaneous emission.

Science.gov (United States)

Zhang, Peng; Wu, Di; Du, Quanli; Li, Xiaoyan; Han, Kexuan; Zhang, Lizhong; Wang, Tianshu; Jiang, Huilin

2017-12-10

A 1.7 μm band tunable narrow-linewidth Raman fiber laser based on spectrally sliced amplified spontaneous emission (SS-ASE) and multiple filter structures is proposed and experimentally demonstrated. In this scheme, an SS-ASE source is employed as a pump source in order to avoid stimulated Brillouin scattering. The ring configuration includes a 500 m long high nonlinear optical fiber and a 10 km long dispersion shifted fiber as the gain medium. A segment of un-pumped polarization-maintaining erbium-doped fiber is used to modify the shape of the spectrum. Furthermore, a nonlinear polarization rotation scheme is applied as the wavelength selector to generate lasers. A high-finesse ring filter and a ring filter are used to narrow the linewidth of the laser, respectively. We demonstrate tuning capabilities of a single laser over 28 nm between 1652 nm and 1680 nm by adjusting the polarization controller (PC) and tunable filter. The tunable laser has a 0.023 nm effective linewidth with the high-finesse ring filter. The stable multi-wavelength laser operation of up to four wavelengths can be obtained by adjusting the PC carefully when the pump power increases.

Narrow linewidth operation of a spectral beam combined diode laser bar.

Science.gov (United States)

Zhu, Zhanda; Jiang, Menghua; Cheng, Siqi; Hui, Yongling; Lei, Hong; Li, Qiang

2016-04-20

Our experiment is expected to provide an approach for realizing ultranarrow linewidth for a spectral beam combined diode laser bar. The beams of a diode laser bar are combined in a fast axis after a beam transformation system. With the help of relay optics and a transform lens with a long focal length of 1.5 m, the whole wavelength of a spectral combined laser bar can be narrowed down to 0.48 nm from more than 10 nm. We have achieved 56.7 W cw from a 19-element single bar with an M2 of 1.4  (in horizontal direction)×11.6  (in vertical direction). These parameters are good evidence that all the beams from the diode laser bar are combined together to increase the brightness.

Narrow linewidth short cavity Brillouin random laser based on Bragg grating array fiber and dynamical population inversion gratings

Science.gov (United States)

Popov, S. M.; Butov, O. V.; Chamorovski, Y. K.; Isaev, V. A.; Mégret, P.; Korobko, D. A.; Zolotovskii, I. O.; Fotiadi, A. A.

2018-06-01

We report on random lasing observed with 100-m-long fiber comprising an array of weak FBGs inscribed in the fiber core and uniformly distributed over the fiber length. Extended fluctuation-free oscilloscope traces highlight power dynamics typical for lasing. An additional piece of Er-doped fiber included into the laser cavity enables a stable laser generation with a linewidth narrower than 10 kHz.

A narrow linewidth tunable single longitudinal mode Ga-EDF fiber laser

Science.gov (United States)

Mohamed Halip, N. H.; Abu Bakar, M. H.; Latif, A. A.; Muhd-Yasin, S. Z.; Zulkifli, M. I.; Mat-Sharif, K. A.; Omar, N. Y. M.; Mansoor, A.; Abdul-Rashid, H. A.; Mahdi, M. A.

2018-05-01

A tunable ring cavity single longitudinal mode (SLM) fiber laser incorporating Gallium-Erbium co-doped fiber (Ga-EDF) gain medium and several mode filtration techniques is demonstrated. With Ga-EDF, high emission power was accorded in short fiber length, allowing shorter overall cavity length and wider free spectral range. Tunable bandpass filter, sub-ring structure, and cascaded dissimilar fiber taper were utilized to filter multi-longitudinal modes. Each of the filter mechanism was tested individually within the laser cavity to assess its performance. Once the performance of each filter was obtained, all of them were deployed into the laser system. Ultimately, the 1561.47 nm SLM laser achieved a narrow linewidth laser, optical signal-to-noise ratio, and power fluctuation of 1.19 kHz, 61.52 dB and 0.16 dB, respectively. This work validates the feasibility of Ga-EDF to attain a stable SLM output in simple laser configuration.

Universal gate-set for trapped-ion qubits using a narrow linewidth diode laser

International Nuclear Information System (INIS)

Akerman, Nitzan; Navon, Nir; Kotler, Shlomi; Glickman, Yinnon; Ozeri, Roee

2015-01-01

We report on the implementation of a high fidelity universal gate-set on optical qubits based on trapped 88 Sr + ions for the purpose of quantum information processing. All coherent operations were performed using a narrow linewidth diode laser. We employed a master-slave configuration for the laser, where an ultra low expansion glass Fabry–Perot cavity is used as a stable reference as well as a spectral filter. We characterized the laser spectrum using the ions with a modified Ramsey sequence which eliminated the affect of the magnetic field noise. We demonstrated high fidelity single qubit gates with individual addressing, based on inhomogeneous micromotion, on a two-ion chain as well as the Mølmer–Sørensen two-qubit entangling gate. (paper)

Nanodiamonds with photostable, sub-gigahertz linewidth quantum emitters

Directory of Open Access Journals (Sweden)

Toan Trong Tran

2017-11-01

Full Text Available Single-photon emitters with narrow linewidths are highly sought after for applications in quantum information processing and quantum communications. In this letter, we report on a bright, highly polarized near infrared single photon emitter embedded in diamond nanocrystals with a narrow, sub-GHz optical linewidth at 10 K. The observed zero-phonon line at ∼780 nm is optically stable under low power excitation and blue shifts as the excitation power increases. Our results highlight the prospect for using new near infrared color centers in nanodiamonds for quantum applications.

Nanodiamonds with photostable, sub-gigahertz linewidth quantum emitters

Science.gov (United States)

Tran, Toan Trong; Kianinia, Mehran; Bray, Kerem; Kim, Sejeong; Xu, Zai-Quan; Gentle, Angus; Sontheimer, Bernd; Bradac, Carlo; Aharonovich, Igor

2017-11-01

Single-photon emitters with narrow linewidths are highly sought after for applications in quantum information processing and quantum communications. In this letter, we report on a bright, highly polarized near infrared single photon emitter embedded in diamond nanocrystals with a narrow, sub-GHz optical linewidth at 10 K. The observed zero-phonon line at ˜780 nm is optically stable under low power excitation and blue shifts as the excitation power increases. Our results highlight the prospect for using new near infrared color centers in nanodiamonds for quantum applications.

Linewidth and phase locking of Josephson flux flow oscillators

DEFF Research Database (Denmark)

Mygind, Jesper; Koshelets, V. P.; Shitov, S. V.

2000-01-01

by the resolution bandwidth of the spectrum analyzer) has been measured. This linewidth is far below the fundamental level given by shot and thermal noise of the free-running tunnel junction. The damping mechanisms are discussed and related to the self-excitation Of quasiparticles. Narrow linewidth, wide...

Narrow linewidth diode laser modules for quantum optical sensor applications in the field and in space

Science.gov (United States)

Wicht, A.; Bawamia, A.; Krüger, M.; Kürbis, Ch.; Schiemangk, M.; Smol, R.; Peters, A.; Tränkle, G.

2017-02-01

We present the status of our efforts to develop very compact and robust diode laser modules specifically suited for quantum optics experiments in the field and in space. The paper describes why hybrid micro-integration and GaAs-diode laser technology is best suited to meet the needs of such applications. The electro-optical performance achieved with hybrid micro-integrated, medium linewidth, high power distributed-feedback master-oscillator-power-amplifier modules and with medium power, narrow linewidth extended cavity diode lasers emitting at 767 nm and 780 nm are briefly described and the status of space relevant stress tests and space heritage is summarized. We also describe the performance of an ECDL operating at 1070 nm. Further, a novel and versatile technology platform is introduced that allows for integration of any type of laser system or electro-optical module that can be constructed from two GaAs chips. This facilitates, for the first time, hybrid micro-integration, e.g. of extended cavity diode laser master-oscillator-poweramplifier modules, of dual-stage optical amplifiers, or of lasers with integrated, chip-based phase modulator. As an example we describe the implementation of an ECDL-MOPA designed for experiments on ultra-cold rubidium and potassium atoms on board a sounding rocket and give basic performance parameters.

Narrow optical linewidths and spin pumping on charge-tunable close-to-surface self-assembled quantum dots in an ultrathin diode

Science.gov (United States)

Löbl, Matthias C.; Söllner, Immo; Javadi, Alisa; Pregnolato, Tommaso; Schott, Rüdiger; Midolo, Leonardo; Kuhlmann, Andreas V.; Stobbe, Søren; Wieck, Andreas D.; Lodahl, Peter; Ludwig, Arne; Warburton, Richard J.

2017-10-01

We demonstrate full charge control, narrow optical linewidths, and optical spin pumping on single self-assembled InGaAs quantum dots embedded in a 162.5 -nm -thin diode structure. The quantum dots are just 88 nm from the top GaAs surface. We design and realize a p -i -n -i -n diode that allows single-electron charging of the quantum dots at close-to-zero applied bias. In operation, the current flow through the device is extremely small resulting in low noise. In resonance fluorescence, we measure optical linewidths below 2 μ eV , just a factor of 2 above the transform limit. Clear optical spin pumping is observed in a magnetic field of 0.5 T in the Faraday geometry. We present this design as ideal for securing the advantages of self-assembled quantum dots—highly coherent single-photon generation, ultrafast optical spin manipulation—in the thin diodes required in quantum nanophotonics and nanophononics applications.

A highly efficient Ho:YAG laser in-band pumped by a linewidth-narrowed Tm:YLF laser

International Nuclear Information System (INIS)

Duan, X M; Yang, C H; Yao, B Q; Wang, Y Z; Zhang, W S

2013-01-01

A highly efficient Tm:YLF-Ho:YAG laser system is presented in this paper. To obtain the narrow linewidth 1908 nm laser output, a volume Bragg grating combined with a Fabry–Perot (FP) etalon were used as wavelength selection devices. The maximum output power of 28.7 W was obtained with a slope efficiency of 42.3% in the Tm:YLF laser. An output wavelength of 1908.1 nm and FWHM linewidth of 60 pm were achieved at the maximum output level. Using this Tm:YLF laser as the pump source, high efficiency continuous wave and Q-switched operation of a Ho:YAG laser was demonstrated. Operating at continuous wave mode, up to 73.3% slope efficiency and 67.4% optical conversion efficiency were obtained in the Ho:YAG laser, corresponding to a diode-to-Ho optical conversion efficiency of 23.7%. For the Q-switched mode, when the incident Tm power was 27.3 W, the maximum single pulse energy of 3.4 mJ, pulse width of 15 ns and peak power of 229.3 kW were achieved at the pulse repetition rate of 5 kHz. The maximum average power of 18.3 W, pulse width of 18 ns and peak power of 103.6 kW were obtained at the pulse repetition rate of 10 kHz. (paper)

Iodine Absorption Cells Purity Testing

Directory of Open Access Journals (Sweden)

Jan Hrabina

2017-01-01

Full Text Available This article deals with the evaluation of the chemical purity of iodine-filled absorption cells and the optical frequency references used for the frequency locking of laser standards. We summarize the recent trends and progress in absorption cell technology and we focus on methods for iodine cell purity testing. We compare two independent experimental systems based on the laser-induced fluorescence method, showing an improvement of measurement uncertainty by introducing a compensation system reducing unwanted influences. We show the advantages of this technique, which is relatively simple and does not require extensive hardware equipment. As an alternative to the traditionally used methods we propose an approach of hyperfine transitions’ spectral linewidth measurement. The key characteristic of this method is demonstrated on a set of testing iodine cells. The relationship between laser-induced fluorescence and transition linewidth methods will be presented as well as a summary of the advantages and disadvantages of the proposed technique (in comparison with traditional measurement approaches.

Composition-dependent emission linewidth broadening in lead bromide perovskite (APbBr3, A = Cs and CH3NH3) nanoparticles.

Science.gov (United States)

Ham, Sujin; Chung, Heejae; Kim, Tae-Woo; Kim, Jiwon; Kim, Dongho

2018-02-01

Lead halide perovskite nanoparticles (NPs) are attractive as they exhibit excellent color purity and have a tunable band gap, and can thus be applied in highly efficient photovoltaic and light-emitting diodes. Fundamental studies of emission linewidth broadening due to spectral shifts in perovskite NPs may suggest a way to improve their color purity. However, the carrier-induced Stark shift that causes spectral diffusion still requires investigation. In this study, we explore composition-related emission linewidth broadening by comparing CsPbBr3 and CH 3 NH 3 PbBr 3 (MAPbBr3) perovskite NPs. We find that the MAPbBr3 NPs are more sensitive to fluctuations in the local electric fields than the CsPbBr3 NPs due to an intrinsic difference in the dipole moment between the two A cations (Cs and MA), which shows a carrier-induced Stark shift. The results indicate that the compositions of perovskite NPs are closely associated with emission linewidth broadening and they also provide insights into the development of NP-based devices with high color purity.

Digital frequency offset-locked He–Ne laser system with high beat frequency stability, narrow optical linewidth and optical fibre output

Science.gov (United States)

Sternkopf, Christian; Manske, Eberhard

2018-06-01

We report on the enhancement of a previously-presented heterodyne laser source on the basis of two phase-locked loop (PLL) frequency coupled internal-mirror He–Ne lasers. Our new system consists of two digitally controlled He–Ne lasers with slightly different wavelengths, and offers high-frequency stability and very narrow optical linewidth. The digitally controlled system has been realized by using a FPGA controller and transconductance amplifiers. The light of both lasers was coupled into separate fibres for heterodyne interferometer applications. To enhance the laser performance we observed the sensitivity of both laser tubes to electromagnetic noise from various laser power supplies and frequency control systems. Furthermore, we describe how the linewidth of a frequency-controlled He–Ne laser can be reduced during precise frequency stabilisation. The digitally controlled laser source reaches a standard beat frequency deviation of less than 20 Hz (with 1 s gate time) and a spectral full width at half maximum (FWHM) of the beat signal less than 3 kHz. The laser source has enough optical output power to serve a fibre-coupled multi axis heterodyne interferometer. The system can be adjusted to output beat frequencies in the range of 0.1 MHz–20 MHz.

Dynamic properties of quantum dot distributed feedback lasers: high speed, linewidth and chirp

International Nuclear Information System (INIS)

Su Hui; Lester, Luke F

2005-01-01

The dynamic properties of distributed feedback lasers (DFBs) based on InAs/InGaAs quantum dots (QDs) are studied. The response function of QD DFBs under external modulation is measured, and the gain compression with photon density is identified to be the limiting factor of the modulation bandwidth. The enhancement of the gain compression by the gain saturation with the carrier density in QDs is also analysed for the first time. The linewidth of the QD DFBs is found to be more than one order of magnitude narrower than that of conventional quantum well (QW) DFBs at comparable output powers. The figure of merit for the narrow linewidth is compared between different semiconductor materials, including bulk, QWs and QDs. Linewidth re-broadening and the effects of gain offset are also investigated. Finally, the chirp of QD DFBs is studied by time-resolved-chirp measurements. The wavelength chirping of the QD DFBs under 2.5 Gbps modulation is characterized. The strong dependence of the linewidth enhancement factor on the photon density is explained by the enhancement of gain compression by the gain saturation with the carrier density, which is related to the inhomogeneous broadening and spectral hole burning in QDs

Temperature dependence of spectral linewidth of InAs/InP quantum dot distributed feedback lasers

Science.gov (United States)

Duan, J.; Huang, H.; Schires, K.; Poole, P. J.; Wang, C.; Grillot, F.

2018-02-01

In this paper, we investigate the temperature dependence of spectral linewidth of InAs/InP quantum dot distributed feedback lasers. In comparison with their quantum well counterparts, results show that quantum dot lasers have spectral linewidths rather insensitive to the temperature with minimum values below 200 kHz in the range of 283K to 303K. The experimental results are also well confirmed by numerical simulations. Overall, this work shows that quantum dot lasers are excellent candidates for various applications such as coherent communication systems, high-resolution spectroscopy, high purity photonic microwave generation and on-chip atomic clocks.

2.43 kW narrow linewidth linearly polarized all-fiber amplifier based on mode instability suppression

Science.gov (United States)

Su, Rongtao; Tao, Rumao; Wang, Xiaolin; Zhang, Hanwei; Ma, Pengfei; Zhou, Pu; Xu, Xiaojun

2017-08-01

We demonstrate an experimental study on scaling mode instability (MI) threshold in fiber amplifiers based on fiber coiling. The experimental results show that coiling the active fiber in the cylindrical spiral shape is superior to the coiling in the plane spiral shape. When the polarization maintained Yb-doped fiber (PM YDF: with a core/inner-cladding diameter of 20/400 µm) is coiled on an aluminous plate with a bend diameter of 9-16 cm, the MI threshold is ~1.55 kW. When such a PM YDF is coiled on an aluminous cylinder with diameter of 9 cm, no MI is observed at the output power of 2.43 kW, which is limited by the available pump power. The spectral width and polarization extinction ratio is 0.255 nm and 18.3 dB, respectively, at 2.43 kW. To the best of our knowledge, this is the highest output power from a linear polarized narrow linewidth all-fiberized amplifier. By using a theoretical model, the potential MI-free scaling capability in such an amplifier is estimated to be 3.5 kW.

Effects of iron deficiency on anisotropy and ferromagnetic resonance linewidth in Bi-doped LiZn ferrite

Directory of Open Access Journals (Sweden)

Xiaona Jiang

2017-05-01

Full Text Available Bi-doped LiZn ferrites with different iron deficiencies were fabricated by a conventional ceramic method. Anisotropy constant (K1 was calculated and ferromagnetic resonance (FMR linewidth (ΔH was investigated. Crystalline anisotropy broadening linewidth (ΔHa and porosity broadening linewidth (ΔHp were derived by an approximate calculation based on dipolar narrowing theory, which play a significant role in contributions to FMR linewidth and occupy more than 90 % of ΔH. Physical and static magnetic properties of LiZn ferrite with iron deficiency are presented, which supports a decline in linewidths with increasing iron deficiency. Iron deficiency makes K1, ΔHa and ΔHp reduce. The results also show that ΔHp is the majority of contributions to ΔH in Bi-doped LiZn ferrite and densification is an effective method to decrease ΔH.

Intrinsic homogeneous linewidth and broadening mechanisms of excitons in monolayer transition metal dichalcogenides

KAUST Repository

Moody, Galan

2015-09-18

The band-edge optical response of transition metal dichalcogenides, an emerging class of atomically thin semiconductors, is dominated by tightly bound excitons localized at the corners of the Brillouin zone (valley excitons). A fundamental yet unknown property of valley excitons in these materials is the intrinsic homogeneous linewidth, which reflects irreversible quantum dissipation arising from system (exciton) and bath (vacuum and other quasiparticles) interactions and determines the timescale during which excitons can be coherently manipulated. Here we use optical two-dimensional Fourier transform spectroscopy to measure the exciton homogeneous linewidth in monolayer tungsten diselenide (WSe2). The homogeneous linewidth is found to be nearly two orders of magnitude narrower than the inhomogeneous width at low temperatures. We evaluate quantitatively the role of exciton–exciton and exciton–phonon interactions and population relaxation as linewidth broadening mechanisms. The key insights reported here—strong many-body effects and intrinsically rapid radiative recombination—are expected to be ubiquitous in atomically thin semiconductors.

Narrow-line external cavity diode laser micro-packaging in the NIR and MIR spectral range

Science.gov (United States)

Jiménez, A.; Milde, T.; Staacke, N.; Aßmann, C.; Carpintero, G.; Sacher, J.

2017-07-01

Narrow-linewidth tunable diode lasers are an important tool for spectroscopic instrumentation. Conventional external cavity diode lasers offer high output power and narrow linewidth. However, most external cavity diode lasers are designed as laboratory instrument and do not allow portability. In comparison, other commonly used lasers, like distributed feedback lasers (DFB) that are capable of driving a handheld device, are limited in power and show linewidths which are not sufficiently narrow for certain applications. We present new miniaturized types of tunable external cavity diode laser which overcome the drawbacks of conventional external cavity diode lasers and which preserve the advantages of this laser concept. Three different configurations are discussed in this article. The three types of miniaturized external cavity diode laser systems achieve power values of more than 50 mW within the 1.4 μm water vapor absorption band with excellent side-mode suppression and linewidth below 100 kHz. Typical features outstand with respect to other type of laser systems which are of extended use such as DFB laser diodes. The higher output power and the lower linewidth will enable a higher sensitivity and resolution for a wide range of applications.

A comparison of delayed self-heterodyne interference measurement of laser linewidth using Mach-Zehnder and Michelson interferometers.

Science.gov (United States)

Canagasabey, Albert; Michie, Andrew; Canning, John; Holdsworth, John; Fleming, Simon; Wang, Hsiao-Chuan; Aslund, Mattias L

2011-01-01

Linewidth measurements of a distributed feedback (DFB) fibre laser are made using delayed self heterodyne interferometry (DHSI) with both Mach-Zehnder and Michelson interferometer configurations. Voigt fitting is used to extract and compare the Lorentzian and Gaussian linewidths and associated sources of noise. The respective measurements are w(L) (MZI) = (1.6 ± 0.2) kHz and w(L) (MI) = (1.4 ± 0.1) kHz. The Michelson with Faraday rotator mirrors gives a slightly narrower linewidth with significantly reduced error. This is explained by the unscrambling of polarisation drift using the Faraday rotator mirrors, confirmed by comparing with non-rotating standard gold coated fibre end mirrors.

Narrowing of electromagnetically induced transparency resonance in a Doppler-broadened medium

International Nuclear Information System (INIS)

Javan, Ali; Kocharovskaya, Olga; Lee Hwang; Scully, Marlan O.

2002-01-01

We derive an analytic expression for the linewidth of electromagnetically induced transparency (EIT) resonance in a Doppler-broadened system. It is shown here that for relatively low intensity of the driving field the EIT linewidth is proportional to the square root of intensity and is independent of the Doppler width, similar to the laser-induced line narrowing effect described by Feld and Javan. In the limit of high intensity we recover the usual power-broadening case where the EIT linewidth is proportional to the intensity and inversely proportional to the Doppler width

Linewidths and line shapes in the vicinity of graphene

International Nuclear Information System (INIS)

Bhattacharyya, Pallavi; Sebastian, K. L.

2014-01-01

It is well known that graphene, by virtue of its pi-cloud delocalization, has a continuum of electronic energy states and thus behaves nearly like a metal. Instances involving quenching of electronic energy excitation in fluorophores placed in the proximity of graphene sheets are well documented. In this paper, we perform theoretical investigations on the broadening of vibrational and electronic transitions in the vicinity of graphene. We find that for CO vibrations in the vicinity of undoped graphene, the broadening at a distance of 5 Å is ∼0.008 cm −1 (κ ~ =2, κ ~ being the effective dielectric constant). In comparison, for electronic transitions, the linewidth is much larger, being of the order of several cm −1 . Also, if the transition dipole were parallel to the graphene sheet, the linewidth would be reduced to half the value for the case where it is perpendicular, an observation which should be easy to check experimentally for electronic transitions. This should be observable for the f − f transitions (which are rather narrow) of Lanthanide complexes placed within a distance of a few nanometers from a graphene sheet. Further the linewidth would have a (distance) −4 dependence as one varies the distance from graphene

A Comparison of Delayed Self-Heterodyne Interference Measurement of Laser Linewidth Using Mach-Zehnder and Michelson Interferometers

Directory of Open Access Journals (Sweden)

Simon Fleming

2011-09-01

Full Text Available Linewidth measurements of a distributed feedback (DFB fibre laser are made using delayed self heterodyne interferometry (DHSI with both Mach-Zehnder and Michelson interferometer configurations. Voigt fitting is used to extract and compare the Lorentzian and Gaussian linewidths and associated sources of noise. The respective measurements are wL (MZI = (1.6 ± 0.2 kHz and wL (MI = (1.4 ± 0.1 kHz. The Michelson with Faraday rotator mirrors gives a slightly narrower linewidth with significantly reduced error. This is explained by the unscrambling of polarisation drift using the Faraday rotator mirrors, confirmed by comparing with non-rotating standard gold coated fibre end mirrors.

The linewidth and contrast of electromagnetically induced transparency in a homogeneously broadened system

International Nuclear Information System (INIS)

Yang Lijun; Zhang Lianshui; Guo Qinglin; Fu Guangsheng

2007-01-01

In this paper, we present a theoretical study of the linewidth and contrast of electromagnetically induced transparency (EIT). The EIT is associated with a homogenously broadened three-level system interacting with a couple and a probe laser field in a Λ configuration. The optical Bloch equation is solved, from which analytic solutions for the EIT linewidth and contrast are derived. It is shown that the analytical results are in good agreement with the numerical calculation of the EIT spectrum and gives a satisfactory account of the power-broadening behavior for a broad range of the couple laser Rabi frequency where the EIT evolves from a narrow spectral hole into well-separated dynamic Stark doublet

Narrow Wavelength, Frequency Modulated Source at 1.5 Wavelength, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Ultrastable, narrow linewidth, tunable, high reliability sources at 1.5 or 2mm are needed for high performance LIDARs for several NASA applications, including wind...

Spectral purity and tunability of terahertz quantum cascade laser sources based on intracavity difference-frequency generation.

Science.gov (United States)

Consolino, Luigi; Jung, Seungyong; Campa, Annamaria; De Regis, Michele; Pal, Shovon; Kim, Jae Hyun; Fujita, Kazuue; Ito, Akio; Hitaka, Masahiro; Bartalini, Saverio; De Natale, Paolo; Belkin, Mikhail A; Vitiello, Miriam Serena

2017-09-01

Terahertz sources based on intracavity difference-frequency generation in mid-infrared quantum cascade lasers (THz DFG-QCLs) have recently emerged as the first monolithic electrically pumped semiconductor sources capable of operating at room temperature across the 1- to 6-THz range. Despite tremendous progress in power output, which now exceeds 1 mW in pulsed and 10 μW in continuous-wave regimes at room temperature, knowledge of the major figure of merits of these devices for high-precision spectroscopy, such as spectral purity and absolute frequency tunability, is still lacking. By exploiting a metrological grade system comprising a terahertz frequency comb synthesizer, we measure, for the first time, the free-running emission linewidth (LW), the tuning characteristics, and the absolute center frequency of individual emission lines of these sources with an uncertainty of 4 × 10 -10 . The unveiled emission LW (400 kHz at 1-ms integration time) indicates that DFG-QCLs are well suited to operate as local oscillators and to be used for a variety of metrological, spectroscopic, communication, and imaging applications that require narrow-LW THz sources.

Nanodiamonds carrying silicon-vacancy quantum emitters with almost lifetime-limited linewidths

Science.gov (United States)

Jantzen, Uwe; Kurz, Andrea B.; Rudnicki, Daniel S.; Schäfermeier, Clemens; Jahnke, Kay D.; Andersen, Ulrik L.; Davydov, Valery A.; Agafonov, Viatcheslav N.; Kubanek, Alexander; Rogers, Lachlan J.; Jelezko, Fedor

2016-07-01

Colour centres in nanodiamonds are an important resource for applications in quantum sensing, biological imaging, and quantum optics. Here we report unprecedented narrow optical transitions for individual colour centres in nanodiamonds smaller than 200 nm. This demonstration has been achieved using the negatively charged silicon vacancy centre, which has recently received considerable attention due to its superb optical properties in bulk diamond. We have measured an ensemble of silicon-vacancy centres across numerous nanodiamonds to have an inhomogeneous distribution of 1.05 nm at 5 K. Individual spectral lines as narrower than 360 MHz were measured in photoluminescence excitation, and correcting for apparent spectral diffusion yielded an homogeneous linewidth of about 200 MHz which is close to the lifetime limit. These results indicate the high crystalline quality achieved in these nanodiamond samples, and advance the applicability of nanodiamond-hosted colour centres for quantum optics applications.

Nanodiamonds carrying silicon-vacancy quantum emitters with almost lifetime-limited linewidths

International Nuclear Information System (INIS)

Jantzen, Uwe; Kurz, Andrea B; Jahnke, Kay D; Kubanek, Alexander; Rogers, Lachlan J; Jelezko, Fedor; Rudnicki, Daniel S; Schäfermeier, Clemens; Andersen, Ulrik L; Davydov, Valery A; Agafonov, Viatcheslav N

2016-01-01

Colour centres in nanodiamonds are an important resource for applications in quantum sensing, biological imaging, and quantum optics. Here we report unprecedented narrow optical transitions for individual colour centres in nanodiamonds smaller than 200 nm. This demonstration has been achieved using the negatively charged silicon vacancy centre, which has recently received considerable attention due to its superb optical properties in bulk diamond. We have measured an ensemble of silicon-vacancy centres across numerous nanodiamonds to have an inhomogeneous distribution of 1.05 nm at 5 K. Individual spectral lines as narrower than 360 MHz were measured in photoluminescence excitation, and correcting for apparent spectral diffusion yielded an homogeneous linewidth of about 200 MHz which is close to the lifetime limit. These results indicate the high crystalline quality achieved in these nanodiamond samples, and advance the applicability of nanodiamond-hosted colour centres for quantum optics applications. (paper)

On the frequency and field linewidth conversion of ferromagnetic resonance spectra

International Nuclear Information System (INIS)

Wei, Yajun; Svedlindh, Peter; Liang Chin, Shin

2015-01-01

Both frequency swept and field swept ferromagnetic resonance measurements have been carried out for a number of different samples with negligible, moderate and significant extrinsic frequency independent linewidth contribution to analyze the correlation between the experimentally measured frequency and field linewidths. Contrary to the belief commonly held by many researchers, it is found that the frequency and field linewidth conversion relation does not hold for all cases. Instead it holds only for samples with negligible frequency independent linewidth contributions. For samples with non-negligible frequency independent linewidth contribution, the field linewidth values converted from the measured frequency linewidth are larger than the experimentally measured field linewidth. A close examination of the literature reveals that previously reported results support our findings, with successful conversions related to samples with negligible frequency independent linewidth contributions and unsuccessful conversions related to samples with significant frequency independent linewidth. The findings are important in providing guidance in ferromagnetic resonance linewidth conversions. (paper)

QSOs with narrow emission lines

International Nuclear Information System (INIS)

Baldwin, J.A.; Mcmahon, R.; Hazard, C.; Williams, R.E.

1988-01-01

Observations of two new high-redshift, narrow-lined QSOs (NLQSOs) are presented and discussed together with observations of similar objects reported in the literature. Gravitational lensing is ruled out as a possible means of amplifying the luminosity for one of these objects. It is found that the NLQSOs have broad bases on their emission lines as well as the prominent narrow cores which define this class. Thus, these are not pole-on QSOs. The FWHM of the emission lines fits onto the smoothly falling tail of the lower end of the line-width distribution for complete QSO samples. The equivalent widths of the combined broad and narrow components of the lines are normal for QSOs of the luminosity range under study. However, the NLQSOs do show ionization differences from broader-lined QSOs; most significant, the semiforbidden C III/C IV intensity ratio is unusually low. The N/C abundance ratio in these objects is found to be normal; the Al/C abundance ratio may be quite high. 38 references

Water-vapor absorption line measurements in the 940-nm band by using a Raman-shifted dye laser

Science.gov (United States)

Chu, Zhiping; Wilkerson, Thomas D.; Singh, Upendra N.

1993-01-01

We report water-vapor absorption line measurements that are made by using the first Stokes radiation (930-982 nm) with HWHM 0.015/cm generated by a narrow-linewidth, tunable dye laser. Forty-five absorption line strengths are measured with an uncertainty of 6 percent and among them are fourteen strong lines that are compared with previous measurements for the assessment of spectral purity of the light source. Thirty air-broadened linewidths are measured with 8 percent uncertainty at ambient atmospheric pressure with an average of 0.101/cm. The lines are selected for the purpose of temperature-sensitive or temperature-insensitive lidar measurements. Results for these line strengths and linewidths are corrected for broadband radiation and finite laser linewidth broadening effects and compared with the high-resolution transmission molecular absorption.

Microcavity polariton linewidths in the weak-disorder regime

DEFF Research Database (Denmark)

Borri, Paola; Langbein, Wolfgang Werner; Woggon, U.

2000-01-01

Polariton linewidths have been measured in a series of high-quality microcavities with different excitonic inhomogeneous broadening in the weak-disorder regime. We show experimentally that the influence of the disorder on the polariton linewidths is canceled when the polariton energies are far in...... in the tail of the excitonic absorption. The measured linewidths are quantitatively compared with an estimation using the measured excitonic absorption spectrum of the bare quantum wells, and good agreement is found....

Uncertainty estimates of purity measurements based on current information: toward a "live validation" of purity methods.

Science.gov (United States)

Apostol, Izydor; Kelner, Drew; Jiang, Xinzhao Grace; Huang, Gang; Wypych, Jette; Zhang, Xin; Gastwirt, Jessica; Chen, Kenneth; Fodor, Szilan; Hapuarachchi, Suminda; Meriage, Dave; Ye, Frank; Poppe, Leszek; Szpankowski, Wojciech

2012-12-01

To predict precision and other performance characteristics of chromatographic purity methods, which represent the most widely used form of analysis in the biopharmaceutical industry. We have conducted a comprehensive survey of purity methods, and show that all performance characteristics fall within narrow measurement ranges. This observation was used to develop a model called Uncertainty Based on Current Information (UBCI), which expresses these performance characteristics as a function of the signal and noise levels, hardware specifications, and software settings. We applied the UCBI model to assess the uncertainty of purity measurements, and compared the results to those from conventional qualification. We demonstrated that the UBCI model is suitable to dynamically assess method performance characteristics, based on information extracted from individual chromatograms. The model provides an opportunity for streamlining qualification and validation studies by implementing a "live validation" of test results utilizing UBCI as a concurrent assessment of measurement uncertainty. Therefore, UBCI can potentially mitigate the challenges associated with laborious conventional method validation and facilitates the introduction of more advanced analytical technologies during the method lifecycle.

LD-cladding-pumped 50 pm linewidth Tm 3+ -doped silica fiber laser.

Science.gov (United States)

Yunjun, Zhang; Baoquan, Yao; Youlun, Ju; Hui, Zhou; Yuezhu, Wang

2008-05-26

We report on a Tm(3+)-doped fiber laser source operating at 1936.4 nm with a very narrow linewidth (50 pm) laser output. Up to 2.4 W cw laser power was obtained from an 82 cm long Tm(3+)-doped multimode-core fiber cladding pumped by a 792 nm laser diode (LD). The fiber laser cavity included a high-reflective dichroic and a low-reflective FBG output coupler. The multimode fiber Bragg grating (FBG) transmission spectrum and output laser spectrum were measured. By adjusting the distance between the dichroic and the Tm(3+)-doped fiber end, the multipeak laser spectrum changed to a single-peak laser spectrum.

Temperature dependence of the chromium(III) R1 linewidth in emerald

Science.gov (United States)

Carceller-Pastor, Ivana; Hutchison, Wayne D.; Riesen, Hans

2013-03-01

The temperature dependent contribution to the R1 (2E ← 4A2) linewidth in emerald, Be3Al2Si6O18:Cr3, has been measured by employing spectral hole-burning, fluorescence line narrowing and conventional luminescence experiments. The contribution varies from 0.6 MHz at 6.5 K to ˜420 GHz at 240 K and the line red-shifts by ˜570 GHz. Above 60 K, the dependence is well described by a non-perturbative formalism for two-phonon Raman scattering. Below this temperature the direct one-phonon process between the levels of the split 2E excited state dominates. However, it appears that a localized low-energy phonon leads to a deviation from the standard pattern at lowest temperatures.

Narrow-line laser cooling by adiabatic transfer

Science.gov (United States)

Norcia, Matthew A.; Cline, Julia R. K.; Bartolotta, John P.; Holland, Murray J.; Thompson, James K.

2018-02-01

We propose and demonstrate a novel laser cooling mechanism applicable to particles with narrow-linewidth optical transitions. By sweeping the frequency of counter-propagating laser beams in a sawtooth manner, we cause adiabatic transfer back and forth between the ground state and a long-lived optically excited state. The time-ordering of these adiabatic transfers is determined by Doppler shifts, which ensures that the associated photon recoils are in the opposite direction to the particle’s motion. This ultimately leads to a robust cooling mechanism capable of exerting large forces via a weak transition and with reduced reliance on spontaneous emission. We present a simple intuitive model for the resulting frictional force, and directly demonstrate its efficacy for increasing the total phase-space density of an atomic ensemble. We rely on both simulation and experimental studies using the 7.5 kHz linewidth 1S0 to 3P1 transition in 88Sr. The reduced reliance on spontaneous emission may allow this adiabatic sweep method to be a useful tool for cooling particles that lack closed cycling transitions, such as molecules.

Intensities, broadening and narrowing parameters in the ν3 band of methane

KAUST Repository

Es-sebbar, Et-touhami; Farooq, Aamir

2014-01-01

The P-branch of methane's ν3 band is probed to carry out an extensive study of the 2905-2908cm-1 infrared spectral region. Absolute line intensities as well as N2-, O2-, H2-, He-, Ar- and CO2-broadening coefficients are determined for nine transitions at room temperature. Narrowing parameters due to the Dicke effect have also been investigated. A narrow emission line-width (~0.0001cm-1) difference-frequency-generation (DFG) laser system is used as the tunable light source. To retrieve the CH4 spectroscopic parameters, Voigt and Galatry profiles were used to simulate the measured line shape of the individual transitions.

Intensities, broadening and narrowing parameters in the ν3 band of methane

KAUST Repository

Es-sebbar, Et-touhami

2014-12-01

The P-branch of methane\\'s ν3 band is probed to carry out an extensive study of the 2905-2908cm-1 infrared spectral region. Absolute line intensities as well as N2-, O2-, H2-, He-, Ar- and CO2-broadening coefficients are determined for nine transitions at room temperature. Narrowing parameters due to the Dicke effect have also been investigated. A narrow emission line-width (~0.0001cm-1) difference-frequency-generation (DFG) laser system is used as the tunable light source. To retrieve the CH4 spectroscopic parameters, Voigt and Galatry profiles were used to simulate the measured line shape of the individual transitions.

Dependence of inhomogeneous vibrational linewidth broadening on attractive forces from local liquid number densities

International Nuclear Information System (INIS)

George, S.M.; Harris, C.B.

1982-01-01

The dependence of inhomogeneous vibrational linewidth broadening on attractive forces form slowly varying local liquid number densities is examined. The recently developed Schweizer--Chandler theory of vibrational dephasing is used to compute absolute inhomogeneous broadening linewidths. The computed linewidths are compared to measured inhomogeneous broadening linewidths determined using picosecond vibrational dephasing experiments. There is a similarity between correlations of the Schweizer--Chandler and George--Auweter--Harris predicted inhomogeneous broadening linewidths and the measured inhomogeneous broadening linewidths. For the methyl stretches under investigation, this correspondence suggests that the width of the number density distribution in the liquid determines the relative inhomogeneous broadening magnitudes

Chemomechanical nanolithography: nanografting on silicon and factors impacting linewidth.

Science.gov (United States)

Lee, Michael V; Hoffman, Melinda Tonks; Barnett, Katherine; Geiss, John-Mark; Smentkowski, Vincent S; Linford, Matthew R; Davis, Robert C

2006-06-01

We present a two-fold extension of previous work on Atomic Force Microscope-based chemomechanical functionalization: (1) chemomechanical nanografting, which extends chemomechanical functionalization to a more stable initial surface, and (2) linewidth studies that show the impact of force and Atomic Force Microscope probe tip wear on patterning resolution. Alkene, alcohol, and alkyl halide molecules were nanografted to silicon and imaged with in situ atomic force microscopy, time-of-flight secondary ion mass spectrometry with Automated eXpert Spectrum Image Analysis, and scanning electron microscopy. Chemomechanical nanografting demonstrated linewidths down to 50 nm. Lines written on hydrogen-terminated silicon were used to explore the impact of tip radius and tip wear on linewidth when using Si3N4 coated tips.

Volume Bragg grating narrowed high-power and highly efficient cladding-pumped Raman fiber laser.

Science.gov (United States)

Liu, Jun; Yao, Weichao; Zhao, Chujun; Shen, Deyuan; Fan, Dianyuan

2014-12-10

High-power and highly efficient operation of a single-mode cladding-pumped Raman fiber laser with narrow lasing bandwidth is demonstrated. The spectral narrowing was realized by an external cavity containing a volume Bragg grating with a center wavelength of 1658 nm. A maximum output power of 10.4 W at 1658.3 nm with a spectral linewidth (FWHM) of ∼0.1  nm was obtained for the launched pump power of 18.4 W, corresponding to a slope efficiency of 109% with respect to the launched pump power. Lasing characteristics of free-running operation are also evaluated and discussed.

Narrow-band light emission from a single carbon nanotube p-n diode

Science.gov (United States)

Kinoshita, Megumi; Mueller, Thomas; Steiner, Mathias; Perebeinos, Vasili; Bol, Ageeth; Farmer, Damon; Avouris, Phaedon

2010-03-01

We present the first observation of electroluminescence from electrostatically-generated carbon nanotube (CNT) p-n junctions[1]. While CNT optoelectronics has made much progress in recent years, observations of emission from electrically excited CNT devices have been limited to the high-bias regime and with low efficiency. Furthermore, the resulting broad linewidths are broad, making it difficult to investigate electronic levels and carrier dynamics. We find that p-n junctions allow for better carrier control at lower power inputs, resulting in emission with near-zero threshold, low self-heating and efficiency two to three orders of magnitude greater compared to previous device configurations. This yields higher signal-to-noise ratio and narrower linewidths (down to ˜35 meV) that allows us to identify localized excitonic transitions that have previously been observed only in photoluminescent studies. [1] T. Mueller, M. Kinoshita, M. Steiner, V. Perebeinos, A. Bol, D. Farmer, and Ph. Avouris, Nature Nanotech., web publication, November 15 2009.

Linewidth and tuning characteristics of terahertz quantum cascade lasers.

Science.gov (United States)

Barkan, A; Tittel, F K; Mittleman, D M; Dengler, R; Siegel, P H; Scalari, G; Ajili, L; Faist, J; Beere, H E; Linfield, E H; Davies, A G; Ritchie, D A

2004-03-15

We have measured the spectral linewidths of three continuous-wave quantum cascade lasers operating at terahertz frequencies by heterodyning the free-running quantum cascade laser with two far-infrared gas lasers. Beat notes are detected with a GaAs diode mixer and a microwave spectrum analyzer, permitting very precise frequency measurements and giving instantaneous linewidths of less than -30 kHz. Characteristics are also reported for frequency tuning as the injection current is varied.

Linewidth statistics of single InGaAs quantum dot photolumincescence lines

DEFF Research Database (Denmark)

Leosson, Kristjan; Jensen, Jacob Riis; Hvam, Jørn Märcher

2000-01-01

We have used photoluminescence spectroscopy with high spatial and spectral resolution to measure the linewidths of single emission lines from In0.5Ga0.5As/GaAs self-assembled quantum dots. At 10 K, we find a broad, asymmetric distribution of linewidths with a maximum at 50 mu eV. The distribution......-dot luminescence lines depends only weakly on temperature up to 50 K, showing a broadening of 0.4 mu eV/K. Above 50 K, a thermally activated behavior of the linewidth is observed. This temperature dependence is consistent with the discrete energy level structure of the dots....

Frequency and temperature dependence of ferromagnetic linewidth in exchange biased Permalloy

International Nuclear Information System (INIS)

Lubitz, P.; Rubinstein, M.; Krebs, J. J.; Cheng, S.-F.

2001-01-01

Ferromagnetic resonance linewidths were measured at 9.5 and 35 GHz and in the temperature range from 77 to 350 K for thin Permalloy (Py) films exchange biased by adjacent layers of NiO, CoO, or IrMn. Compared to unoxidized Py alone, for which the linewidth is nearly temperature independent in this range and scales linearly with frequency, exchange biased Py has broader lines with distinctive temperature dependences for each bias material at 9.5 GHz. Different temperature dependences were observed at 35 GHz. Our results are consistent with relaxation related to thermally driven reversal of the antiferromagnetic grains. Intrinsic damping and inhomogeneities also add to the widths. The qualitative features of the temperature and frequency dependences of the linewidths can be described with the usual expression for the slow relaxation linewidth mechanism. The temperature dependence of the relaxation time is taken from Neel's expression for the reversal time using appropriate rate prefactors and activation energies. [copyright] 2001 American Institute of Physics

Testing ultrafast mode-locking at microhertz relative optical linewidth.

Science.gov (United States)

Martin, Michael J; Foreman, Seth M; Schibli, T R; Ye, Jun

2009-01-19

We report new limits on the phase coherence of the ultrafast mode-locking process in an octave-spanning Ti:sapphire comb.We find that the mode-locking mechanism correlates optical phase across a full optical octave with less than 2.5 microHZ relative linewidth. This result is at least two orders of magnitude below recent predictions for quantum-limited individual comb-mode linewidths, verifying that the mode-locking mechanism strongly correlates quantum noise across the comb spectrum.

Testing ultrafast mode-locking at microhertz relative optical linewidth

OpenAIRE

Martin, Michael J.; Foreman, Seth M.; Schibli, T. R.; Ye, Jun

2008-01-01

We report new limits on the phase coherence of the ultrafast mode-locking process in an octave-spanning Ti:sapphire comb. We find that the mode-locking mechanism correlates optical phase across a full optical octave with less than 2.5 micro Hz relative linewidth. This result is at least two orders of magnitude below recent predictions for quantum-limited individual comb-mode linewidths, verifying that the mode-locking mechanism strongly correlates quantum noise across the comb spectrum.

Ferromagnetic resonance linewidth and two-magnon scattering in Fe1-xGdx thin films

Directory of Open Access Journals (Sweden)

Sheng Jiang

2017-05-01

Full Text Available Magnetization dynamics of Fe1-xGdx thin films (0 ≤ x ≤ 22% has been investigated by ferromagnetic resonance (FMR. Out-of-plane magnetic field orientation dependence of resonance field and linewidth has been measured. Resonance field and FMR linewidth have been fitted by the free energy of our system and Landau-Lifshitz-Gilbert (LLG equation. It is found that FMR linewidth contains huge extrinsic components including two-magnon scattering contribution and inhomogeneous broadening for FeGd alloy thin films. In addition, the intrinsic linewidth and real damping constants have been obtained by extracting the extrinsic linewidth. The damping constant enhanced from 0.011 to 0.038 as Gd dopants increase from 0 to 22% which originates from the enhancement of L-S coupling in FeGd thin films. Besides, gyromagnetic ratio, Landé factor g and magnetic anisotropy of our films have also been determined.

Sub-megahertz linewidth single photon source

Directory of Open Access Journals (Sweden)

Markus Rambach

2016-12-01

Full Text Available We report 100% duty cycle generation of sub-MHz single photon pairs at the rubidium D1 line using cavity-enhanced spontaneous parametric downconversion. The temporal intensity cross correlation function exhibits a bandwidth of 666±16 kHz for the single photons, an order of magnitude below the natural linewidth of the target transition. A half-wave plate inside our cavity helps to achieve triple resonance between pump, signal, and idler photon, reducing the bandwidth and simplifying the locking scheme. Additionally, stabilisation of the cavity to the pump frequency enables the 100% duty cycle. The quantum nature of the source is confirmed by the idler-triggered second-order autocorrelation function at τ=0 to be gs,s(2(0= 0.016±0.002 for a heralding rate of 5 kHz. The generated photons are well-suited for storage in quantum memory schemes with sub-natural linewidths, such as gradient echo memories.

Design of narrow band photonic filter with compact MEMS for tunable resonant wavelength ranging 100 nm

Directory of Open Access Journals (Sweden)

Guanquan Liang

2011-12-01

Full Text Available A prototype of planar silicon photonic structure is designed and simulated to provide narrow resonant line-width (∼2 nm in a wide photonic band gap (∼210 nm with broad tunable resonant wavelength range (∼100 nm around the optical communication wavelength 1550 nm. This prototype is based on the combination of two modified basic photonic structures, i.e. a split tapered photonic crystal micro-cavity embedded in a photonic wire waveguide, and a slot waveguide with narrowed slabs. This prototype is then further integrated with a MEMS (microelectromechanical systems based electrostatic comb actuator to achieve “coarse tune” and “fine tune” at the same time for wide range and narrow-band filtering and modulating. It also provides a wide range tunability to achieve the designed resonance even fabrication imperfection occurs.

Modelling linewidths of Kepler red giants in NGC 6819

Science.gov (United States)

Aarslev, Magnus J.; Houdek, Günter; Handberg, Rasmus; Christensen-Dalsgaard, Jørgen

2018-04-01

We present a comparison between theoretical, frequency-dependent, damping rates and linewidths of radial-mode oscillations in red-giant stars located in the open cluster NGC 6819. The calculations adopt a time-dependent non-local convection model, with the turbulent pressure profile being calibrated to results of 3D hydrodynamical simulations of stellar atmospheres. The linewidths are obtained from extensive peakbagging of Kepler lightcurves. These observational results are of unprecedented quality owing to the long continuous observations by Kepler. The uniqueness of the Kepler mission also means that, for asteroseismic properties, this is the best data that will be available for a long time to come. We therefore take great care in modelling nine RGB stars in NGC 6819 using information from 3D simulations to obtain realistic temperature stratifications and calibrated turbulent pressure profiles. Our modelled damping rates reproduce well the Kepler observations, including the characteristic depression in the linewidths around the frequency of maximum oscillation power. Furthermore, we thoroughly test the sensitivity of the calculated damping rates to changes in the parameters of the nonlocal convection model.

Linewidth broadening in a distributed feedback laser integrated with a semiconductor optical amplifier

DEFF Research Database (Denmark)

Champagne, A.; Camel, J.; Maciejko, R.

2002-01-01

The problem of the linewidth degradation in systems using distributed-feedback lasers together with strained-layer multi-quantum-well semiconductor optical amplifiers (SOAs) is examined. A modified expression for the linewidth in the case of antireflection-coated SOA output facets is derived and ...

Annealing effects on the microwave linewidth broadening of FeCuNbSiB ferromagnetic films

Energy Technology Data Exchange (ETDEWEB)

Alves, M. J. P.; Gonzalez-Chavez, D. E.; Sommer, R. L. [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca, 22290-180 Rio de Janeiro, RJ (Brazil); Bohn, F. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil)

2015-03-28

We systematically investigate the annealing effects on the microwave linewidth broadening of FeCuNbSiB ferromagnetic films with thickness of 100 nm. We correlate the non-uniform residual stress obtained from grazing incidence x-ray diffraction measurements with the ferromagnetic resonance (FMR) linewidth due to effective field inhomogeneities measured from broadband ferromagnetic resonance absorption measurements. We also estimate the annealing temperature effect on the Gilbert and two-magnon scattering contributions to the total ferromagnetic resonance FMR linewidth. We show that the effective field inhomogeneities constitute the main contribution to the microwave linewidth, while this contribution is related to the non-uniform residual stress in the films which is reduced by thermal annealing.

Differential scanning calorimetry method for purity determination: A case study on polycyclic aromatic hydrocarbons and chloramphenicol

International Nuclear Information System (INIS)

Kestens, V.; Zeleny, R.; Auclair, G.; Held, A.; Roebben, G.; Linsinger, T.P.J.

2011-01-01

Highlights: → Purity assessment of polycyclic aromatic hydrocarbons and chloramphenicol by DSC. → DSC results compared with traditional purity methods. → Different methods give different results, multiple method approach recommended. → DSC sensitive to impurities that have similar structures as main component. - Abstract: In this study the validity and suitability of differential scanning calorimetry (DSC) to determine the purity of selected polycyclic aromatic hydrocarbons and chloramphenicol has been investigated. The study materials were two candidate certified reference materials (CRMs), 6-methylchrysene and benzo[a]pyrene, and two different batches of commercially available highly pure chloramphenicol. The DSC results were compared with those obtained by other methods, namely gas and liquid chromatography with mass spectrometric detection, liquid chromatography with diode array detection, and quantitative nuclear magnetic resonance. The purity results obtained by these different analytical methods confirm the well-known challenges of comparing results of different method-defined measurands. In comparison with other methods, DSC has a much narrower working range. This limits the applicability of DSC as purity determination method, for instance during the assignment of the purity value of a CRM. Nevertheless, this study showed that DSC can be a powerful technique to detect impurities that are structurally very similar to the main purity component. From this point of view, and because of its good repeatability, DSC can be considered as a valuable technique to investigate the homogeneity and stability of candidate purity CRMs.

The effect of the negative binomial distribution on the line-width of the micromaser cavity field

International Nuclear Information System (INIS)

Kremid, A. M.

2009-01-01

The influence of negative binomial distribution (NBD) on the line-width of the negative binomial distribution (NBD) on the line-width of the micromaser is considered. The threshold of the micromaser is shifted towards higher values of the pumping parameter q. Moreover the line-width exhibits sharp dips 'resonances' when the cavity temperature reduces to a very low value. These dips are very clear evidence for the occurrence of the so-called trapping states regime in the micromaser. This statistics prevents the appearance of these trapping states, namely by increasing the negative binomial parameter q these dips wash out and the line-width becomes more broadening. For small values of the parameter q the line-width at large values of q randomly oscillates around its transition line. As q becomes large this oscillatory behavior occurs at rarely values of q. (author)

Ultrabroad linewidth orange-emitting nanowires LED for high CRI laser-based white lighting and gigahertz communications

KAUST Repository

Janjua, Bilal

2016-08-10

Group-III-nitride laser diode (LD)-based solid-state lighting device has been demonstrated to be droop-free compared to light-emitting diodes (LEDs), and highly energy-efficient compared to that of the traditional incandescent and fluorescent white light systems. The YAG:Ce3+ phosphor used in LD-based solid-state lighting, however, is associated with rapid degradation issue. An alternate phosphor/LD architecture, which is capable of sustaining high temperature, high power density, while still intensity- and bandwidth-tunable for high color-quality remained unexplored. In this paper, we present for the first time, the proof-of-concept of the generation of high-quality white light using an InGaN-based orange nanowires (NWs) LED grown on silicon, in conjunction with a blue LD, and in place of the compound-phosphor. By changing the relative intensities of the ultrabroad linewidth orange and narrow-linewidth blue components, our LED/LD device architecture achieved correlated color temperature (CCT) ranging from 3000 K to above 6000K with color rendering index (CRI) values reaching 83.1, a value unsurpassed by the YAG-phosphor/blue-LD counterpart. The white-light wireless communications was implemented using the blue LD through on-off keying (OOK) modulation to obtain a data rate of 1.06 Gbps. We therefore achieved the best of both worlds when orange-emitting NWs LED are utilized as “active-phosphor”, while blue LD is used for both color mixing and optical wireless communications.

Measurement of the linewidth enhancement factor based on nonlinear polarization rotation of semiconductor optical amplifier.

Science.gov (United States)

Liu, Guodong; Wu, Chongqing; Wang, Fu; Zhang, Tianyong; Shang, Chao; Gao, Kaiqiang

2015-06-01

A simple measurement scheme of the linewidth enhancement factor based on the nonlinear polarization rotation of a semiconductor optical amplifier is proposed. Considering the polarization dependent gain, the relationship between the linewidth enhancement factor and the Stokes vector was derived theoretically. It is proven that the linewidth enhancement factor can be calculated directly from the Stokes parameters without any other assistant measurement system. The results demonstrate that the linewidth enhancement factor varies in a small range from 10.5 to 8.5 for TE mode and from 8.2 to 5.8 for TM mode, respectively, when the input optical power varies from 50 μW to 1 mW and the bias current varies from 90 to 170 mA.

Spectral linewidth preservation in parametric frequency combs seeded by dual pumps.

Science.gov (United States)

Tong, Zhi; Wiberg, Andreas O J; Myslivets, Evgeny; Kuo, Bill P P; Alic, Nikola; Radic, Stojan

2012-07-30

We demonstrate new technique for generation of programmable-pitch, wideband frequency combs with low phase noise. The comb generation was achieved using cavity-less, multistage mixer driven by two tunable continuous-wave pump seeds. The approach relies on phase-correlated continuous-wave pumps in order to cancel spectral linewidth broadening inherent to parametric comb generation. Parametric combs with over 200-nm bandwidth were obtained and characterized with respect to phase noise scaling to demonstrate linewidth preservation over 100 generated tones.

Temperature Dependence of the Rayleigh Brillouin Spectrum Linewidth in Air and Nitrogen

Directory of Open Access Journals (Sweden)

Kun Liang

2017-06-01

Full Text Available The relation between spontaneous Rayleigh Brillouin (SRB spectrum linewidth, gas temperature, and pressure are analyzed at the temperature range from 220 to 340 K and the pressure range from 0.1 to 1 bar, covering the stratosphere and troposphere relevant for the Earth’s atmosphere and for atmospheric Lidar missions. Based on the analysis, a model retrieving gas temperature from directly measured linewidth is established and the accuracy limitations are estimated. Furthermore, some experimental data of air and nitrogen are used to verify the accuracy of the model. As the results show, the retrieved temperature shows good agreement with the reference temperature, and the absolute difference is less than 3 K, which indicates that this method provides a fruitful tool in satellite retrieval to extract the gaseous properties of atmospheres on-line by directly measuring the SRB spectrum linewidth.

The effect of broadened linewidth induced by dispersion on the performance of resonant optical gyroscope

Science.gov (United States)

Zhang, Hao; Li, Wenxiu; Han, Peng; Chang, Xiaoyang; Liu, Jiaming; Lin, Jian; Xue, Xia; Zhu, Fang; Yang, Yang; Liu, Xiaojing; Zhang, Xiaofu; Huang, Anping; Xiao, Zhisong; Fang, Jiancheng

2018-01-01

Anomalous dispersion enhancement physical mechanism for Sagnac effect is described by special relativity derivation, and three kinds of definitions of minimum detectable angular rate of resonance optical gyroscope (ROG) are compared and the relations among them are investigated. The effect of linewidth broadening induced by anomalous dispersion on the sensitivity of ROG is discussed in this paper. Material dispersion-broadened resonance linewidth deteriorates the performance of a passive ROG and dispersion enhancement effect, while the sensitivity of a structural dispersion ROG is enhanced by two orders of magnitude even considering the dispersion-broadened resonance linewidth.

Linewidths in OCS: Isotope effects, vibrational effects, temperature dependence, and T1/T2

International Nuclear Information System (INIS)

Creswell, R.A.; Brown, S.R.; Schwendeman, R.H.

1976-01-01

A computer-controlled microwave spectrometer has been used to record the frequency dependence of the absorption of the J=2reverse arrow1 transition of OCS under varying conditions of pressure, temperature, and microwave power. From least-squares fits of the data to Lorentzian line shapes, a variety of linewidths and linewidth parameters have been deduced. The linewidth parameter for the J=2reverse arrow1 transition of 16 O 12 C 32 S in the ground vibrational state has been determined to be 6.03+-0.05 MHz/torr. The ratios of linewidth parameters for this transition for several other species to that for the ground state of 16 O 12 C 32 S are: 16 O 12 C 34 S, ground state, 0.987+-0.003; 16 O 13 C 32 S, ground state, 0.991+-0.005; 18 O 12 C 32 S, ground state, 0.966+-0.018; 16 O 12 C 32 S, v 3 =1, 1.024+-0.026; 16 O 12 C 32 S, v 2 /subl/=2degree, 0.978+-0.003. The linewidth parameter for the ground state of the parent species was determined to be inversely proportional to the absolute temperature in the range 297--346 K. From comparison of theoretical and experimental power-broadened lineshapes it is shown that T 1 /T 2 =1.04+-0.10 for the transition

Ultra-narrow EIA spectra of 85Rb atom in a degenerate Zeeman multiplet system

Science.gov (United States)

Rehman, Hafeez Ur; Qureshi, Muhammad Mohsin; Noh, Heung-Ryoul; Kim, Jin-Tae

2015-05-01

Ultra-narrow EIA spectral features of thermal 85Rb atom with respect to coupling Rabi frequencies in a degenerate Zeeman multiplet system have been unraveled in the cases of same (σ+ -σ+ , π ∥ π) and orthogonal (σ+ -σ- , π ⊥ π)polarization configurations. The EIA signals with subnatural linewidth of ~ 100 kHz even in the cases of same circular and linear polarizations of coupling and probe laser have been obtained for the first time theoretically and experimentally. In weak coupling power limit of orthogonal polarization configurations, time-dependent transfer of coherence plays major role in the splitting of the EIA spectra while in strong coupling power, Mollow triplet-like mechanism due to strong power bring into broad split feature. The experimental ultra-narrow EIA features using one laser combined with an AOM match well with simulated spectra obtained by using generalized time-dependent optical Bloch equations.

Narrow linewidth pulsed optical parametric oscillator

Indian Academy of Sciences (India)

also because of high laser damage threshold coating on mirror as well as on crystal. Now-a-days with the development of coating technology and with the availability of good optical quality crystals having high damage threshold and deep infrared. (IR) transparency it is possible to extend the tunability of the OPO.

Narrow-line, cw orange light generation in a diode-pumped Nd:YVO4 laser using volume Bragg gratings.

Science.gov (United States)

Chen, Y L; Chen, W W; Du, C E; Chang, W K; Wang, J L; Chung, T Y; Chen, Y H

2009-12-07

We report on the demonstration of a narrow-line, cw orange 593-nm laser achieved via intracavity sum-frequency generation (SFG) of a diode-pumped dual-wavelength (1064 and 1342 nm) Nd:YVO(4) laser using two volume Bragg grating (VBG) reflectors. At diode pump power of up to 3.6 W, the 593-nm intracavity SFG laser radiates at the single longitudinal mode of spectral linewidth as narrow as approximately 15 MHz. More than 23-mW single-longitudinal-mode or 40-mW, diode pump power) 593-nm orange lights can be obtained from this compact laser system. Spectral tuning of the orange light was performed via the temperature tuning of the two VBGs in this system, achieving an effective tuning rate of ~5 pm/degrees C.

DFB laser diodes for sensing applications using photoacoustic spectroscopy

International Nuclear Information System (INIS)

Koeth, J; Fischer, M; Legge, M; Seufert, J; Roessner, K; Groninga, H

2010-01-01

We present typical device characteristics of novel DFB laser diodes which are employed in various sensing applications including high resolution photoacoustic spectroscopy. The laser diodes discussed are based on a genuine fabrication technology which allows for the production of ultra stable devices within a broad spectral range from 760 nm up to 3000 nm wavelength. The devices exhibit narrow linewidths down to <1 MHz which makes them ideally suited for all photoacoustic sensing applications where a high spectral purity is required. As an example we will focus on a typical medical application where these diodes are used for breath analysis using photoacoustic spectroscopy.

Generation of narrow-band polarization-entangled photon pairs at a rubidium D1 line

International Nuclear Information System (INIS)

Tian Long; Li Shujing; Yuan Haoxiang; Wang Hai

2016-01-01

Using the process of cavity-enhanced spontaneous parametric down-conversion (SPDC), we generate a narrow-band polarization-entangled photon pair resonant on the rubidium (Rb) D1 line (795 nm). The degenerate single-mode photon pair is selected by multiple temperature controlled etalons. The linewidth of generated polarization-entangled photon pairs is 15 MHz which matches the typical atomic memory bandwidth. The measured Bell parameter for the polarization-entangled photons S = 2.73 ± 0.04 which violates the Bell-CHSH inequality by ∼18 standard deviations. The presented entangled photon pair source could be utilized in quantum communication and quantum computing based on quantum memories in atomic ensemble. (author)

Anomalously large ferromagnetic resonance linewidth in the Gd/Cr/Fe film plane

Science.gov (United States)

Sun, Li; Zhang, Wen; Wong, Ping Kwan Johnny; Yin, Yuli; Jiang, Sheng; Huang, Zhaocong; Zhai, Ya; Yao, Zhongyu; Du, Jun; Sui, Yunxia; Zhai, Hongru

2018-04-01

As an important parameter for characterizing the magnetization dynamics, Gilbert damping constant α in a thin film or a multilayer is generally extracted from the linear fitting of the frequency-dependence of the ferromagnetic resonance linewidth, sometimes accompanied with a tiny deviation of the linewidth to a smaller value at the low-frequency or high-frequency region due to the two-magnon scattering with an in-plane-field configuration, in which an in-plane magnetic field H perpendicular to a microwave field h was applied in film plane during measurement. In contrast, here we report, in ultrathin Gd/Cr/Fe multilayers, an anomalously large linewidth in the film plane at the low-frequency region. For the first time, we have successfully extracted the Gilbert damping constant from perfect theoretical fitting to the experimental data, by considering the effective direction of the magnetization around in precession staying out of the film plane when the in-pane H at which the precession starts is below the saturation field. This magnetization deviation from the film plane is found to have an obvious contribution to the enhanced linewidth caused by two magnon scattering, while slightly reduce the intrinsic linewidth. Under the same resonance frequency, the deviation angle reaches the maximum values at tCr = 1.0 nm while decreases when tCr increases to 1.5 nm, which coincides with the trend of the surface perpendicular anisotropy constant K⊥. A reduced intrinsic damping constant α is obtained as the introduction of Gd layer and Cr layer as a result of the competition between the spin pumping effect and the interfacial effects at the Fe/Gd and Fe/Cr interfaces. While the decreasing α for film with Cr layer thickness increasing to 1.5 nm might means the contribution of the electron density of states at the Fermi energy n(EF). This study offers an effective way to accurately obtain the intrinsic damping constant of spintronic materials/devices, which is essential

Ferromagnetic resonance linewidth and damping in perpendicular-anisotropy magnetic multilayers thin films

Science.gov (United States)

Beaujour, Jean-Marc

2010-03-01

Transition metal ferromagnetic films with perpendicular magnetic anisotropy (PMA) have ferromagnetic resonance (FMR) linewidths that are one order of magnitude larger than soft magnetic materials, such as pure iron (Fe) and permalloy (NiFe) thin films. We have conducted systematic studies of a variety of thin film materials with perpendicular magnetic anisotropy to investigate the origin of the enhanced FMR linewidths, including Ni/Co and CoFeB/Co/Ni multilayers. In Ni/Co multilayers the PMA was systematically reduced by irradiation with Helium ions, leading to a transition from out-of-plane to in-plane easy axis with increasing He ion fluence [1,2]. The FMR linewidth depends linearly on frequency for perpendicular applied fields and increases significantly when the magnetization is rotated into the film plane with an applied in-plane magnetic field. Irradiation of the film with Helium ions decreases the PMA and the distribution of PMA parameters, leading to a large reduction in the FMR linewidth for in-plane magnetization. These results suggest that fluctuations in the PMA lead to a large two magnon scattering contribution to the linewidth for in-plane magnetization and establish that the Gilbert damping is enhanced in such materials (α˜0.04, compared to α˜0.002 for pure Fe) [2]. We compare these results to those on CoFeB/Co/Ni and published results on other thin film materials with PMA [e.g., Ref. 3]. [1] D. Stanescu et al., J. Appl. Phys. 103, 07B529 (2008). [2] J-M. L. Beaujour, D. Ravelosona, I. Tudosa, E. Fullerton, and A. D. Kent, Phys. Rev. B RC 80, 180415 (2009). [3] N. Mo, J. Hohlfeld, M. ulIslam, C. S. Brown, E. Girt, P. Krivosik, W. Tong, A. Rebel, and C. E. Patton, Appl. Phys. Lett. 92, 022506 (2008). *Research done in collaboration with: A. D. Kent, New York University, D. Ravelosona, Institut d'Electronique Fondamentale, UMR CNRS 8622, Universit'e Paris Sud, E. E. Fullerton, Center for Magnetic Recording Research, UCSD, and supported by NSF

Opacity broadening and interpretation of suprathermal CO linewidths: Macroscopic turbulence and tangled molecular clouds

Science.gov (United States)

Hacar, A.; Alves, J.; Burkert, A.; Goldsmith, P.

2016-06-01

Context. Since their first detection in the interestellar medium, (sub-)millimeter line observations of different CO isotopic variants have routinely been employed to characterize the kinematic properties of the gas in molecular clouds. Many of these lines exhibit broad linewidths that greatly exceed the thermal broadening expected for the low temperatures found within these objects. These observed suprathermal CO linewidths are assumed to originate from unresolved supersonic motions inside clouds. Aims: The lowest rotational J transitions of some of the most abundant CO isotopologues, 12CO and 13CO, are found to present large optical depths. In addition to well-known line saturation effects, these large opacities present a non-negligible contribution to their observed linewidths. Typically overlooked in the literature, in this paper we aim to quantify the impact of these opacity broadening effects on the current interpretation of the CO suprathermal line profiles. Methods: Combining large-scale observations and LTE modeling of the ground J = 1-0 transitions of the main 12CO, 13CO, C18O isotopologues, we have investigated the correlation of the observed linewidths as a function of the line opacity in different regions of the Taurus molecular cloud. Results: Without any additional contributions to the gas velocity field, a large fraction of the apparently supersonic (ℳ ~ 2-3) linewidths measured in both 12CO and 13CO (J = 1-0) lines can be explained by the saturation of their corresponding sonic-like, optically thin C18O counterparts assuming standard isotopic fractionation. Combined with the presence of multiple components detected in some of our C18O spectra, these opacity effects also seem to be responsible for most of the highly supersonic linewidths (ℳ > 8-10) detected in some of the broadest 12CO and 13CO spectra in Taurus. Conclusions: Our results demonstrate that most of the suprathermal 12CO and 13CO linewidths reported in nearby clouds like Taurus

Disgust and the moralization of purity.

Science.gov (United States)

Horberg, E J; Oveis, Christopher; Keltner, Dacher; Cohen, Adam B

2009-12-01

Guided by appraisal-based models of the influence of emotion upon judgment, we propose that disgust moralizes--that is, amplifies the moral significance of--protecting the purity of the body and soul. Three studies documented that state and trait disgust, but not other negative emotions, moralize the purity moral domain but not the moral domains of justice or harm/care. In Study 1, integral feelings of disgust, but not integral anger, predicted stronger moral condemnation of behaviors violating purity. In Study 2, experimentally induced disgust, compared with induced sadness, increased condemnation of behaviors violating purity and increased approval of behaviors upholding purity. In Study 3, trait disgust, but not trait anger or trait fear, predicted stronger condemnation of purity violations and greater approval of behaviors upholding purity. We found that, confirming the domain specificity of the disgust-purity association, disgust was unrelated to moral judgments about justice (Studies 1 and 2) or harm/care (Study 3). Finally, across studies, individuals of lower socioeconomic status (SES) were more likely than individuals of higher SES to moralize purity but not justice or harm/care.

Narrow groove gas metal-arc welding of aluminum

International Nuclear Information System (INIS)

Armstrong, R.E.

1975-01-01

The Gas Metal-Arc (GMA) welding process is explained and the equipment used described with an analysis of power supply function and the action of the arc, followed by discussion of general applications and problems. GMA braze welding of beryllium is then described, as is the development of a special high purity filler wire and a narrow deep groove joint design for improved weld strength in beryllium. This joint design and the special wire are applied in making high strength welds in high strength aluminum for special applications. High speed motion pictures of the welding operation are shown to illustrate the talk. (auth)

Preliminary Design of a Synchronized Narrow Bandwidth FEL for Taiwan Light Source

CERN Document Server

Keung Lau Wai; Ching Fan, Tai; Zone Hsiao Feng; Tung Hsu Kuo; Hwang, Ching Shiang; Cheng Kuo Chin; Huei Luo Guo; Jen Wang Duan; Ping Wang Jau; Huey Wang Min

2004-01-01

Design study of a narrow line-width, high power IR-FEL facility has been carried out at NSRRC. This machine is designed to synchronize with the U9 undulator radiation of Taiwan Light Source and therefore provide new opportunity for chemical dynamics and condensed matter research. It has been proposed to use a super-conducting linac to provide a 60 MeV high quality electron beam to drive a 2.5-10 microns FEL oscillator with U5 undulator. Operating this linac in energy recovery mode will also be considered as an option to improve overall system effeciency and reduce heat loss and radiation dosage at the beam dump. Performance requirements and outcomes from this preliminary design study will be reported.

Ultrabright narrow-band telecom two-photon source for long-distance quantum communication

Science.gov (United States)

Niizeki, Kazuya; Ikeda, Kohei; Zheng, Mingyang; Xie, Xiuping; Okamura, Kotaro; Takei, Nobuyuki; Namekata, Naoto; Inoue, Shuichiro; Kosaka, Hideo; Horikiri, Tomoyuki

2018-04-01

We demonstrate an ultrabright narrow-band two-photon source at the 1.5 µm telecom wavelength for long-distance quantum communication. By utilizing a bow-tie cavity, we obtain a cavity enhancement factor of 4.06 × 104. Our measurement of the second-order correlation function G (2)(τ) reveals that the linewidth of 2.4 MHz has been hitherto unachieved in the 1.5 µm telecom band. This two-photon source is useful for obtaining a high absorption probability close to unity by quantum memories set inside quantum repeater nodes. Furthermore, to the best of our knowledge, the observed spectral brightness of 3.94 × 105 pairs/(s·MHz·mW) is also the highest reported over all wavelengths.

Ferromagnetic linewidth measurements employing electrodynamic model of the magnetic plasmon resonance

Science.gov (United States)

Krupka, Jerzy; Aleshkevych, Pavlo; Salski, Bartlomiej; Kopyt, Pawel

2018-02-01

The mode of uniform precession, or Kittel mode, in a magnetized ferromagnetic sphere, has recently been proven to be the magnetic plasmon resonance. In this paper we show how to apply the electrodynamic model of the magnetic plasmon resonance for accurate measurements of the ferromagnetic resonance linewidth ΔH. Two measurement methods are presented. The first one employs Q-factor measurements of the magnetic plasmon resonance coupled to the resonance of an empty metallic cavity. Such coupled modes are known as magnon-polariton modes, i.e. hybridized modes between the collective spin excitation and the cavity excitation. The second one employs direct Q-factor measurements of the magnetic plasmon resonance in a filter setup with two orthogonal semi-loops used for coupling. Q-factor measurements are performed employing a vector network analyser. The methods presented in this paper allow one to extend the measurement range of the ferromagnetic resonance linewidth ΔH well beyond the limits of the commonly used measurement standards in terms of the size of the samples and the lowest measurable linewidths. Samples that can be measured with the newly proposed methods may have larger size as compared to the size of samples that were used in the standard methods restricted by the limits of perturbation theory.

The particle concentration effect on magnetic resonance linewidth for magnetic liquids with chain aggregates

International Nuclear Information System (INIS)

Marin, C.N.

2002-01-01

Based on the assumption of particle chains formation within a magnetic liquid, computer simulation of the magnetic resonance line is presented. The dependence on particle concentration within a magnetic liquid of magnetic resonance linewidth is analyzed. The computer simulation demonstrates that the particles chaining has an important effect on the enlargement of the magnetic resonance line. Increasing the particle concentration within magnetic liquid leads to an increase in the linewidth. The agreement with some experimental findings is discussed

Impacts of yttrium substitution on FMR line-width and magnetic properties of nickel spinel ferrites

Energy Technology Data Exchange (ETDEWEB)

Ishaque, M., E-mail: ishaqdgk1@gmail.com [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Khan, Muhammad Azhar, E-mail: azhar.khan@iub.edu.pk [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Ali, Irshad; Khan, Hasan M. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Iqbal, M. Asif [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); College of E & ME, National University of Science and Technology, Islamabad (Pakistan); Islam, M.U. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Warsi, Muhammad Farooq [Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan)

2015-05-15

The influence of yttrium (Y) substitution on ferromagnetic resonance (FMR), initial permeability, and magnetic properties of NiFe{sub 2}O{sub 4} ferrites were investigated. It was observed that the FMR line-width decreases with yttrium contents for the substitution level 0≤×≤0.06. Beyond this, the FMR line-width increases with yttrium contents. The nominal composition NiY{sub 0.12}Fe{sub 1.88}O{sub 4} exhibited the smallest FMR line-width ~282 Oe. A significant change in FMR position of nickel–yttrium (Ni–Y) ferrites was observed and it found to exist between 4150 and 4600 Oe. The saturation magnetization was observed to decrease with the increase of yttrium contents and this was referred to the redistribution of cations on octahedral. The coercivity increased from 15 Oe to 59 Oe by increasing the yttrium concentration. The initial permeability decreased from 110 to 35 at 1 MHz by the incorporation of yttrium and this was attributed to the smaller grains which may obstruct the domain wall movement and impede the domain wall motion. The magnetic loss factors of substituted samples exhibit decreasing behavior in the frequency range 1 kHz to 10 MHz. The smaller FMR line-width and reduced magnetic loss factor of the investigated samples suggest the possible use of these materials in high frequency applications. - Highlights: • Influence of Y{sup 3+} substitution on the properties of nickel ferrites is investigated. • Very small FMR line-width (282 Oe) is exhibited by these substituted ferrites. • Fourfold increase in coercivity was observed for NiY{sub 0.24}Fe{sub 1.76}O{sub 4} ferrites.

Linewidth of Cyclotron Absorption in Band-Gap Graphene: Relaxation Time Approximation vs. Monte Carlo Method

OpenAIRE

S.V. Kryuchkov; E.I. Kukhar’; D.V. Zav’yalov

2015-01-01

The power of the elliptically polarized electromagnetic radiation absorbed by band-gap graphene in presence of constant magnetic field is calculated. The linewidth of cyclotron absorption is shown to be non-zero even if the scattering is absent. The calculations are performed analytically with the Boltzmann kinetic equation and confirmed numerically with the Monte Carlo method. The dependence of the linewidth of the cyclotron absorption on temperature applicable for a band-gap graphene in the...

Narrow-linewidth lasers on a silicon chip

NARCIS (Netherlands)

Bernhardi, Edward; Pollnau, Markus; Di Bartolo, Baldassare; Collins, John; Silvestri, Luciano

2015-01-01

Diode-pumped distributed-feedback (DFB) channel waveguide lasers were demonstrated in Er3+-doped and Yb3+-doped Al2O3 on standard thermally ox-idized silicon substrates. Uniform surface-relief Bragg gratings were patterned by laser-interference lithography and etched into the SiO2 top cladding. The

Experimental demonstration of line-width modulation in plasmonic lithography using a solid immersion lens-based active nano-gap control

International Nuclear Information System (INIS)

Lee, Won-Sup; Kim, Taeseob; Choi, Guk-Jong; Lim, Geon; Joe, Hang-Eun; Gang, Myeong-Gu; Min, Byung-Kwon; Park, No-Cheol; Moon, Hyungbae; Kim, Do-Hyung; Park, Young-Pil

2015-01-01

Plasmonic lithography has been used in nanofabrication because of its utility beyond the diffraction limit. The resolution of plasmonic lithography depends on the nano-gap between the nanoaperture and the photoresist surface—changing the gap distance can modulate the line-width of the pattern. In this letter, we demonstrate solid-immersion lens based active non-contact plasmonic lithography, applying a range of gap conditions to modulate the line-width of the pattern. Using a solid-immersion lens-based near-field control system, the nano-gap between the exit surface of the nanoaperture and the media can be actively modulated and maintained to within a few nanometers. The line-widths of the recorded patterns using 15- and 5-nm gaps were 47 and 19.5 nm, respectively, which matched closely the calculated full-width at half-maximum. From these results, we conclude that changing the nano-gap within a solid-immersion lens-based plasmonic head results in varying line-width patterns

Microscopic nature of inhomogeneous line broadening: Analysis of the excitation-line-narrowing spectra of Cf4+ in CeF4

International Nuclear Information System (INIS)

Liu, G.K.; Huang, J.; Beitz, J.V.

1993-01-01

Optical transitions between 5f states of tetravalent californium ion doped (1 metal-atom %) into CeF 4 exhibit unusually large inhomogeneous broadening. The nature of the inhomogeneous broadening in this system has been studied by using fluorescence line narrowing and excitation line narrowing (ELN). It is shown that the energy distributions of different electronic states of Cf 4+ in this system are correlated. In the ELN experiments, reduced excitation linewidth was obtained when selectively monitoring fluorescence emission. A linear relation was observed between the excitation energies of crystal-field states of the 5 G 4' manifold and the fluorescence wavelength monitored across the inhomogeneous profile of a 5 G 6' -- 7 F 6' transition. Analysis of these results by means of a microscopic theory proposed by Laird and Skinner [J. Chem. Phys. 90, 3880 (1989)] has provided insights into the structural properties of this disordered system

Thermal conductivity of high purity vanadium

International Nuclear Information System (INIS)

Jung, W.D.

1975-01-01

The thermal conductivity, Seebeck coefficient, and electrical resistivity of four high-purity vanadium samples were measured over the temperature range 5 to 300 0 K. The highest purity sample had a resistance ratio (rho 273 /rho 4 . 2 ) of 1524. The highest purity sample had a thermal conductivity maximum of 920 W/mK at 9 0 K and had a thermal conductivity of 35 W/mK at room temperature. At low temperatures, the thermal resistivity was limited by the scattering of electrons by impurities and phonons. The thermal resistivity of vanadium departed from Matthiessen's rule at low temperatures. The electrical resistivity and Seebeck coefficient of high purity vanadium showed no anomalous behavior above 130 0 K. The intrinsic electrical resistivity at low temperatures was due primarily to interband scattering of electrons. The Seebeck coefficient was positive from 10 to 240 0 K and had a maximum which was dependent upon sample purity

Towards {sup 31}Mg-β-NMR resonance linewidths adequate for applications in magnesium chemistry

Energy Technology Data Exchange (ETDEWEB)

Stachura, M., E-mail: mstachura@triumf.ca [TRIUMF (Canada); McFadden, R. M. L. [University of British Columbia, Chemistry Department (Canada); Chatzichristos, A.; Dehn, M. H. [University of British Columbia, Department of Physics and Astronomy (Canada); Gottberg, A. [TRIUMF (Canada); Hemmingsen, L. [Københavns Universitet Universitetsparken 5, Kemisk Institut (Denmark); Jancso, A. [University of Szeged, Department of Inorganic and Analytical Chemistry (Hungary); Karner, V. L. [University of British Columbia, Chemistry Department (Canada); Kiefl, R. F. [University of British Columbia, Department of Physics and Astronomy (Canada); Larsen, F. H. [Københavns Universitet Rolighedsvej 26, Institut for Fødevarevidenskab (Denmark); Lassen, J.; Levy, C. D. P.; Li, R. [TRIUMF (Canada); MacFarlane, W. A. [University of British Columbia, Chemistry Department (Canada); Morris, G. D. [TRIUMF (Canada); Pallada, S. [CERN (Switzerland); Pearson, M. R. [TRIUMF (Canada); Szunyogh, D.; Thulstrup, P. W. [Københavns Universitet Universitetsparken 5, Kemisk Institut (Denmark); Voss, A. [University of Jyväskylä, Department of Physics (Finland)

2017-11-15

The span of most chemical shifts recorded in conventional {sup 25}Mg-NMR spectroscopy is ~ 100 ppm. Accordingly, linewidths of ~ 10 ppm or better are desirable to achieve adequate resolution for applications in chemistry. Here we present first high-field {sup 31}Mg- β-NMR measurements of {sup 31}Mg{sup +} ions implanted into a MgO single crystal carried out at the ISAC facility at TRIUMF. The resonances recorded at 2.5 T and 3.5 T show strong linewidth dependency on the applied RF power, ranging from ~ 419 ppm for the highest RF power down to ~ 48 ppm for the lowest one.

Intrinsic homogeneous linewidth and broadening mechanisms of excitons in monolayer transition metal dichalcogenides

KAUST Repository

Moody, Galan; Kavir Dass, Chandriker; Hao, Kai; Chen, Chang-Hsiao; Li, Lain-Jong; Singh, Akshay; Tran, Kha; Clark, Genevieve; Xu, Xiaodong; Berghä user, Gunnar; Malic, Ermin; Knorr, Andreas; Li, Xiaoqin

2015-01-01

unknown property of valley excitons in these materials is the intrinsic homogeneous linewidth, which reflects irreversible quantum dissipation arising from system (exciton) and bath (vacuum and other quasiparticles) interactions and determines

Spectral Narrowing of a Varactor-Integrated Resonant-Tunneling-Diode Terahertz Oscillator by Phase-Locked Loop

Science.gov (United States)

Ogino, Kota; Suzuki, Safumi; Asada, Masahiro

2017-12-01

Spectral narrowing of a resonant-tunneling-diode (RTD) terahertz oscillator, which is useful for various applications of terahertz frequency range, such as an accurate gas spectroscopy, a frequency reference in various communication systems, etc., was achieved with a phase-locked loop system. The oscillator is composed of an RTD, a slot antenna, and a varactor diode for electrical frequency tuning. The output of the RTD oscillating at 610 GHz was down-converted to 400 MHz by a heterodyne detection. The phase noise was transformed to amplitude noise by a balanced mixer and fed back into the varactor diode. The loop filter for a stable operation is discussed. The spectral linewidth of 18.6 MHz in free-running operation was reduced to less than 1 Hz by the feedback.

The submm wave Josephson flux flow oscillator; Linewidth measurements and simple theory

DEFF Research Database (Denmark)

Mygind, Jesper; Koshelets, V. P.; Samuelsen, Mogens Rugholm

2005-01-01

The Flux Flow Oscillator (FFO) is a long Josephson junction in which a DC bias current and a DC magnetic field maintain a unidirectional viscous flow of magnetic flux quanta. The theoretical linewidth of the electromagnetic radiation generated at the end boundary is due to internal current...

Ultra-narrow band diode lasers with arbitrary pulse shape modulation (Conference Presentation)

Science.gov (United States)

Ryasnyanskiy, Aleksandr I.; Smirnov, Vadim; Mokhun, Oleksiy; Glebov, Alexei L.; Glebov, Leon B.

2017-03-01

Wideband emission spectra of laser diode bars (several nanometers) can be largely narrowed by the usage of thick volume Bragg gratings (VBGs) recorded in photo-thermo-refractive glass. Such narrowband systems, with GHz-wide emission spectra, found broad applications for Diode Pumped Alkali vapor Lasers, optically pumped rare gas metastable lasers, Spin Exchange Optical Pumping, atom cooling, etc. Although the majority of current applications of narrow line diode lasers require CW operation, there are a variety of fields where operation in a different pulse mode regime is necessary. Commercial electric pulse generators can provide arbitrary current pulse profiles (sinusoidal, rectangular, triangular and their combinations). The pulse duration and repetition rate however, have an influence on the laser diode temperature, and therefore, the emitting wavelength. Thus, a detailed analysis is needed to understand the correspondence between the optical pulse profiles from a diode laser and the current pulse profiles; how the pulse profile and duty cycle affects the laser performance (e.g. the wavelength stability, signal to noise ratio, power stability etc.). We present the results of detailed studies of the narrowband laser diode performance operating in different temporal regimes with arbitrary pulse profiles. The developed narrowband (16 pm) tunable laser systems at 795 nm are capable of operating in different pulse regimes while keeping the linewidth, wavelength, and signal-to-noise ratio (>20 dB) similar to the corresponding CW modules.

A Narrow-Linewidth Atomic Line Filter for Free Space Quantum Key Distribution under Daytime Atmospheric Conditions

Science.gov (United States)

Brown, Justin; Woolf, David; Hensley, Joel

2016-05-01

Quantum key distribution can provide secure optical data links using the established BB84 protocol, though solar backgrounds severely limit the performance through free space. Several approaches to reduce the solar background include time-gating the photon signal, limiting the field of view through geometrical design of the optical system, and spectral rejection using interference filters. Despite optimization of these parameters, the solar background continues to dominate under daytime atmospheric conditions. We demonstrate an improved spectral filter by replacing the interference filter (Δν ~ 50 GHz) with an atomic line filter (Δν ~ 1 GHz) based on optical rotation of linearly polarized light through a warm Rb vapor. By controlling the magnetic field and the optical depth of the vapor, a spectrally narrow region can be transmitted between crossed polarizers. We find that the transmission is more complex than a single peak and evaluate peak transmission as well as a ratio of peak transmission to average transmission of the local spectrum. We compare filters containing a natural abundance of Rb with those containing isotopically pure 87 Rb and 85 Rb. A filter providing > 95 % transmission and Δν ~ 1.1 GHz is achieved.

Induced high-order resonance linewidth shrinking with multiple coupled resonators in silicon-organic hybrid slotted two-dimensional photonic crystals for reduced optical switching power in bistable devices

Science.gov (United States)

Hoang, Thu Trang; Ngo, Quang Minh; Vu, Dinh Lam; Le, Khai Q.; Nguyen, Truong Khang; Nguyen, Hieu P. T.

2018-01-01

Shrinking the linewidth of resonances induced by multiple coupled resonators is comprehensively analyzed using the coupled-mode theory (CMT) in time. Two types of coupled resonators under investigation are coupled resonator optical waveguides (CROWs) and side-coupled resonators with waveguide (SCREW). We examine the main parameters influencing on the spectral response such as the number of resonators (n) and the phase shift (φ) between two adjacent resonators. For the CROWs geometry consisting of n coupled resonators, we observe the quality (Q) factor of the right- and left-most resonant lineshapes increases n times larger than that of a single resonator. For the SCREW geometry, relying on the phase shift, sharp, and asymmetric resonant lineshape of the high Q factor a narrow linewidth of the spectral response could be achieved. We employ the finite-difference time-domain (FDTD) method to design and simulate two proposed resonators for practical applications. The proposed coupled resonators in silicon-on-insulator (SOI) slotted two-dimensional (2-D) photonic crystals (PhCs) filled and covered with a low refractive index organic material. Slotted PhC waveguides and cavities are designed to enhance the electromagnetic intensity and to confine the light into small cross-sectional area with low refractive index so that efficient optical devices could be achieved. A good agreement between the theoretical CMT analysis and the FDTD simulation is shown as an evidence for our accurate investigation. All-optical switches based on the CROWs in the SOI slotted 2-D PhC waveguide that are filled and covered by a nonlinear organic cladding to overcome the limitations of its well-known intrinsic properties are also presented. From the calculations, we introduce a dependency of the normalized linewidth of the right-most resonance and its switching power of the all-optical switches on number of resonator, n. This result might provide a guideline for all-optical signal processing on

Establishing comparability and compatibility in the purity assessment of high purity zinc as demonstrated by the CCQM-P149 intercomparison

Science.gov (United States)

Vogl, Jochen; Kipphardt, Heinrich; Richter, Silke; Bremser, Wolfram; del Rocío Arvizu Torres, María; Manzano, Judith Velina Lara; Buzoianu, Mirella; Hill, Sarah; Petrov, Panayot; Goenaga-Infante, Heidi; Sargent, Mike; Fisicaro, Paola; Labarraque, Guillaume; Zhou, Tao; Turk, Gregory C.; Winchester, Michael; Miura, Tsutomu; Methven, Brad; Sturgeon, Ralph; Jährling, Reinhard; Rienitz, Olaf; Mariassy, Michal; Hankova, Zuzana; Sobina, Egor; Ivanovich Krylov, Anatoly; Anatolievich Kustikov, Yuri; Vladimirovich Smirnov, Vadim

2018-04-01

For the first time, an international comparison was conducted on the determination of the purity of a high purity element. Participants were free to choose any analytical approach appropriate for their institute’s applications and services. The material tested was a high purity zinc, which had earlier been assessed for homogeneity and previously used in CCQM-K72 for the determination of six defined metallic impurities. Either a direct metal assay of the Zn mass fraction was undertaken by EDTA titrimetry, or an indirect approach was used wherein all impurities, or at least the major ones, were determined and their sum subtracted from ideal purity of 100%, or 1 kg kg-1. Impurity assessment techniques included glow discharge mass spectrometry, inductively coupled plasma mass spectrometry and carrier gas hot extraction/combustion analysis. Up to 91 elemental impurities covering metals, non-metals and semi-metals/metalloids were quantified. Due to the lack of internal experience or experimental capabilities, some participants contracted external laboratories for specific analytical tasks, mainly for the analysis of non-metals. The reported purity, expressed as zinc mass fraction in the high purity zinc material, showed excellent agreement for all participants, with a relative standard deviation of 0.011%. The calculated reference value, w(Zn)  =  0.999 873 kg kg-1, was assigned an asymmetric combined uncertainty of  +0.000 025 kg kg-1 and  -0.000 028 kg kg-1. Comparability amongst participating metrology institutes is thus demonstrated for the purity determination of high purity metals which have no particular difficulties with their decomposition/dissolution process when solution-based analytical methods are used, or which do not have specific difficulties when direct analysis approaches are used. Nevertheless, further development is required in terms of uncertainty assessment, quantification of non-metals and the determination of purity

Analysis of the Purity of Cetrimide by Titrations

DEFF Research Database (Denmark)

Andersen, Jens Enevold Thaulov; Rasmussen, Claus/Dallerup; Nielsen, Hans/Boye

2006-01-01

. Titration by perchloric acid showed a 99.69 ± 0.05 % purity of cetrimide and titration by silver nitrate showed a 99.85% ± 0.05 % purity while the traditional assay method predicted a purity of only 97.1 ± 0.4. It was found that the discrepancy could be identified as differences in selectivity during...

Oscillation mode linewidths of main-sequence and subgiant stars observed by Kepler

DEFF Research Database (Denmark)

Appourchaux, T.; Benomar, O.; Gruberbauer, M.

2012-01-01

Solar-like oscillations have been observed by {{\\it Kepler}} and CoRoT in several solar-type stars. We study the variations of stellar p-mode linewidth as a function of effective temperature. Time series of 9 months of Kepler data have been used. The power spectra of 42 cool main-sequence stars a...

Linewidth-tolerant 10-Gbit/s 16-QAM transmission using a pilot-carrier based phase-noise cancelling technique.

Science.gov (United States)

Nakamura, Moriya; Kamio, Yukiyoshi; Miyazaki, Tetsuya

2008-07-07

We experimentally demonstrated linewidth-tolerant 10-Gbit/s (2.5-Gsymbol/s) 16-quadrature amplitude modulation (QAM) by using a distributed-feedback laser diode (DFB-LD) with a linewidth of 30 MHz. Error-free operation, a bit-error rate (BER) of noise canceling capability provided by a pilot-carrier and standard electronic pre-equalization to suppress inter-symbol interference (ISI) gave clear 16-QAM constellations and floor-less BER characteristics. We evaluated the BER characteristics by real-time measurement of six (three different thresholds for each I- and Q-component) symbol error rates (SERs) with simultaneous constellation observation.

Electron-phonon contribution to the phonon and excited electron (hole) linewidths in bulk Pd

International Nuclear Information System (INIS)

Sklyadneva, I Yu; Leonardo, A; Echenique, P M; Eremeev, S V; Chulkov, E V

2006-01-01

We present an ab initio study of the electron-phonon (e-ph) coupling and its contribution to the phonon linewidths and to the lifetime broadening of excited electron and hole states in bulk Pd. The calculations, based on density-functional theory, were carried out using a linear-response approach in the plane-wave pseudopotential representation. The obtained results for the Eliashberg spectral function α 2 F(ω), e-ph coupling constant λ, and the contribution to the lifetime broadening, Γ e-ph , show strong dependence on both the energy and momentum of an electron (hole) state. The calculation of phonon linewidths gives, in agreement with experimental observations, an anomalously large broadening for the transverse phonon mode T 1 in the Σ direction. In addition, this mode is found to contribute most strongly to the electron-phonon scattering processes on the Fermi surface

NMR imaging of solids with multiple-pulse line narrowing and radiofrequency gradients

International Nuclear Information System (INIS)

Werner, M.H.

1993-01-01

The usual methods of magnetic resonance imaging fail in rigid solids due to the line-shape contributions of dipolar coupling, chemical shift dispersion and anisotropy, and bulk magnetic susceptibility. This dissertation presents a new method of solid-stage imaging by nuclear magnetic resonance which averages away these contributions with multiple-pulse line-narrowing and encodes spatial information with pulsed radiofrequency field gradients. This method is closely related to simultaneously developed methods utilizing pulsed DC gradients, and offers similar improvements in sensitivity and resolution. The advantage of rf gradients is that they can be rapidly switched without inducing eddy currents in the probe or the magnet. In addition, the phases and amplitudes of the rf gradients can be switched by equipment which is already part of an NMR spectrometer capable of solid-state spectroscopy. The line-narrowing and gradient pulses originate in separate rf circuits tuned to the same frequency. Interactions between the circuits have been minimized by a method of active Q-switching which employs PIN diodes in the matching networks of these circuits. Both one- and two-dimensional images are presented. The latter are obtained by a novel method in which the two dimensions of imaging transverse to the static magnetic field are encoded by two orthogonal components of a single rf gradient. A π/2 phase shift of the rf phase relative to that of the line-narrowing pulses selects one component or the other. This arrangement allows the solid-state analogs of versatile imaging sequences based on Fourier imaging and eliminates the need for sample rotation and back-projection methods. Coherent averaging theory is used to analyze this imaging technique and exact numerical simulations on several coupled spins are discussed. These lend insight to the residual linewidth and its dependence on pixel position as well as to the range of applicability of this technique

Towards 31Mg-β-NMR resonance linewidths adequate for applications in magnesium chemistry

DEFF Research Database (Denmark)

Stachura, M.; McFadden, R. M. L.; Chatzichristos, A.

2017-01-01

The span of most chemical shifts recorded in conventional 25Mg-NMR spectroscopy is ~ 100 ppm. Accordingly, linewidths of ~ 10 ppm or better are desirable to achieve adequate resolution for applications in chemistry. Here we present first high-field 31Mg- β-NMR measurements of 31Mg+ ions implanted...

Laser phase and frequency noise measurement by Michelson interferometer composed of a 3 × 3 optical fiber coupler.

Science.gov (United States)

Xu, Dan; Yang, Fei; Chen, Dijun; Wei, Fang; Cai, Haiwen; Fang, Zujie; Qu, Ronghui

2015-08-24

A laser phase and frequency noise measurement method by an unbalanced Michelson interferometer composed of a 3 × 3 optical fiber coupler is proposed. The relations and differences of the power spectral density (PSD) of differential phase and frequency fluctuation, PSD of instantaneous phase and frequency fluctuation, phase noise and linewidth are derived strictly and discussed carefully. The method obtains the noise features of a narrow linewidth laser conveniently without any specific assumptions or noise models. The technique is also used to characterize the noise features of a narrow linewidth external-cavity semiconductor laser, which confirms the correction and robustness of the method.

Phase locking and spectral linewidth of a two-mode terahertz quantum cascade laser

NARCIS (Netherlands)

Baryshev, A.; Hovenier, J.N.; Adam, A.J.L.; Kašalynas, I.; Gao, J.R.; Klaassen, T.O.; Williams, B.S.; Kumar, S.; Hu, Q.; Reno, J.L.

2006-01-01

We have studied the phase locking and spectral linewidth of an ? 2.7?THz quantum cascade laser by mixing its two lateral lasing modes. The beat signal at about 8?GHz is compared with a microwave reference by applying conventional phase lock loop circuitry with feedback to the laser bias current.

Influence of defects on sub-Å optical linewidths in Eu{sup 3+}: Y{sub 2}O{sub 3} particles

Energy Technology Data Exchange (ETDEWEB)

Oliveira Lima, Karmel de [PSL Research University, Chimie ParisTech – CNRS, Institut de Recherche de Chimie Paris, 75005 Paris (France); Rocha Gonçalves, Rogéria [Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes, 3900, CEP 14040-901 Ribeirão Preto, São Paulo, Brasil (Brazil); Giaume, Domitille [PSL Research University, Chimie ParisTech – CNRS, Institut de Recherche de Chimie Paris, 75005 Paris (France); Ferrier, Alban, E-mail: alban.ferrier@chimie-paristech.fr [PSL Research University, Chimie ParisTech – CNRS, Institut de Recherche de Chimie Paris, 75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, 75005 Paris (France); Goldner, Philippe, E-mail: philippe.goldner@chimie-paristech.fr [PSL Research University, Chimie ParisTech – CNRS, Institut de Recherche de Chimie Paris, 75005 Paris (France)

2015-12-15

Rare earth doped nanocrystals have been recently suggested as useful materials for applications in quantum information processing. To reach optical properties closer to bulk crystals ones, it is still necessary to reduce the defects that can arise in nanoscale structures. Here, we probe the defects level by monitoring the inhomogeneous broadening of the {sup 7}F{sub 0}→{sup 5}D{sub 0} transition in particles of 0.3% at% Eu{sup 3+}:Y{sub 2}O{sub 3}. We find that lines as narrow as 14 GHz (0.015 nm), a value comparable to single crystals, can be obtained in 150 nm particles calcinated at 1200 °C. The additional broadening observed for particles calcinated at lower temperature is attributed to defects inside crystallites and not to surface effects. A linear correlation is also observed between optical and Raman linewidths, suggesting that both processes are sensitive to the same defects. {sup 5}D{sub 0} excited state lifetimes are well described by a model based on an effective refractive index and we conclude that the defects causing the inhomogeneous broadening have no effect on the excited state population.

Evaluation of purity with its uncertainty value in high purity lead stick by conventional and electro-gravimetric methods.

Science.gov (United States)

Singh, Nahar; Singh, Niranjan; Tripathy, S Swarupa; Soni, Daya; Singh, Khem; Gupta, Prabhat K

2013-06-26

A conventional gravimetry and electro-gravimetry study has been carried out for the precise and accurate purity determination of lead (Pb) in high purity lead stick and for preparation of reference standard. Reference materials are standards containing a known amount of an analyte and provide a reference value to determine unknown concentrations or to calibrate analytical instruments. A stock solution of approximate 2 kg has been prepared after dissolving approximate 2 g of Pb stick in 5% ultra pure nitric acid. From the stock solution five replicates of approximate 50 g have been taken for determination of purity by each method. The Pb has been determined as PbSO4 by conventional gravimetry, as PbO2 by electro gravimetry. The percentage purity of the metallic Pb was calculated accordingly from PbSO4 and PbO2. On the basis of experimental observations it has been concluded that by conventional gravimetry and electro-gravimetry the purity of Pb was found to be 99.98 ± 0.24 and 99.97 ± 0.27 g/100 g and on the basis of Pb purity the concentration of reference standard solutions were found to be 1000.88 ± 2.44 and 1000.81 ± 2.68 mg kg-1 respectively with 95% confidence level (k = 2). The uncertainty evaluation has also been carried out in Pb determination following EURACHEM/GUM guidelines. The final analytical results quantifying uncertainty fulfills this requirement and gives a measure of the confidence level of the concerned laboratory. Gravimetry is the most reliable technique in comparison to titremetry and instrumental method and the results of gravimetry are directly traceable to SI unit. Gravimetric analysis, if methods are followed carefully, provides for exceedingly precise analysis. In classical gravimetry the major uncertainties are due to repeatability but in electro-gravimetry several other factors also affect the final results.

Production of high purity granular metals: cadmium, zinc, lead

Directory of Open Access Journals (Sweden)

Shcherban A. P.

2017-04-01

Full Text Available Cadmium, zinc and lead are constituent components of many semiconductor compounds. The obtained high purity distillates and ingots are large-size elements, which is not always convenient to use, and thus require additional grinding, which does not always allow maintaining the purity of the original materials. For the growth of semiconductor and scintillation single crystals it is advisable to use "friable" granular high-purity distillates, which can be processed without the risk of contamination. For example, the European low-background experiment LUCIFER required more than 20 kg of high-purity granulated zinc, which was agreed to be supplied by NSC KIPT. This task was then extended to cadmium and lead. Motivated by these tasks, the authors of this paper propose complex processes of deep refining of cadmium, zinc and lead by vacuum distillation. A device producing granules has been developed. The process of granulation of high-purity metals is explored. The purity of produced granules for cadmium and zinc is >99,9999, and >99,9995% for lead granules. To prevent oxidation of metal granules during exposition to air, chemical methods of surface passivation were used. Organic solvent based on dimethylformamide used as a coolant improves the resistance of granules to atmospheric corrosion during the granulation of high purity Cd, Zn and Pb.

Phase locking and spectral linewidth of a two-mode terahertz quantum cascade laser

NARCIS (Netherlands)

Baryshev, A.; Hovenier, J. N.; Adam, A. J. L.; Kašalynas, I.; Gao, J. R.; Klaassen, T. O.; Williams, B. S.; Kumar, S.; Hu, Q.; Reno, J. L.

2006-01-01

We have studied the phase locking and spectral linewidth of an ˜2.7THz quantum cascade laser by mixing its two lateral lasing modes. The beat signal at about 8GHz is compared with a microwave reference by applying conventional phase lock loop circuitry with feedback to the laser bias current. Phase

The split-cross-bridge resistor for measuring the sheet resistance, linewidth, and line spacing of conducting layers

Science.gov (United States)

Buehler, M. G.; Hershey, C. W.

1986-01-01

A new test structure was developed for evaluating the line spacing between conductors on the same layer using an electrical measurement technique. This compact structure can also be used to measure the sheet resistance, linewidth, and line pitch of the conducting layer. Using an integrated-circuit fabrication process, this structure was fabricated in diffused polycrystalline silicon and metal layers and measured optically and electrically. For the techniques used, the optical measurements were typically one-quarter micron greater than the electrical measurements. Most electrically measured line pitch values were within 2 percent of the designed value. A small difference between the measured and designed line pitch is used to validate sheet resistance, linewidth, and line spacing values.

10 CFR 36.63 - Pool water purity.

Science.gov (United States)

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Pool water purity. 36.63 Section 36.63 Energy NUCLEAR... § 36.63 Pool water purity. (a) Pool water purification system must be run sufficiently to maintain the conductivity of the pool water below 20 microsiemens per centimeter under normal circumstances. If pool water...

Strengthening Purity: Moral Purity as a Mediator of Direct and Extended Cross-Group Friendships on Sexual Prejudice.

Science.gov (United States)

Vezzali, Loris; Brambilla, Marco; Giovannini, Dino; Paolo Colucci, Francesco

2017-01-01

The present research investigated whether enhanced perceptions of moral purity drive the effects of intergroup cross-group friendships on the intentions to interact with homosexuals. High-school students (N = 639) reported their direct and extended cross-group friendships with homosexuals as well as their beliefs regarding the moral character of the sexual minority. Participants further reported their desire to interact with homosexuals in the future. Results showed that both face-to-face encounters and extended contact with homosexuals increased their perceived moral purity, which in turn fostered more positive behavioral intentions. Results further revealed the specific role of moral purity in this sense, as differential perceptions along other moral domains (autonomy and community) had no mediation effects on behavioral tendencies toward homosexuals. The importance of these findings for improving intergroup relations is discussed, together with the importance of integrating research on intergroup contact and morality.

Helium gas purity monitor based on low frequency acoustic resonance

Science.gov (United States)

Kasthurirengan, S.; Jacob, S.; Karunanithi, R.; Karthikeyan, A.

1996-05-01

Monitoring gas purity is an important aspect of gas recovery stations where air is usually one of the major impurities. Purity monitors of Katherometric type are commercially available for this purpose. Alternatively, we discuss here a helium gas purity monitor based on acoustic resonance of a cavity at audio frequencies. It measures the purity by monitoring the resonant frequency of a cylindrical cavity filled with the gas under test and excited by conventional telephone transducers fixed at the ends. The use of the latter simplifies the design considerably. The paper discusses the details of the resonant cavity and the electronic circuit along with temperature compensation. The unit has been calibrated with helium gas of known purities. The unit has a response time of the order of 10 minutes and measures the gas purity to an accuracy of 0.02%. The unit has been installed in our helium recovery system and is found to perform satisfactorily.

Batch extractive distillation for high purity methanol

International Nuclear Information System (INIS)

Zhang Weijiang; Ma Sisi

2006-01-01

In this paper, the application in chemical industry and microelectronic industry, market status and the present situation of production of high purity methanol at home and abroad were introduced firstly. Purification of industrial methanol for high purity methanol is feasible in china. Batch extractive distillation is the best separation technique for purification of industrial methanol. Dimethyl sulfoxide was better as an extractant. (authors)

Observation of narrowband intrinsic spectra of Brillouin dynamic gratings.

Science.gov (United States)

Song, Kwang Yong; Yoon, Hyuk Jin

2010-09-01

We experimentally demonstrate that the reflection spectrum of a Brillouin dynamic grating in a polarization-maintaining fiber can be much narrower than the intrinsic linewidth of the stimulated Brillouin scattering, matching well with the theory of a fiber Bragg grating in terms of the linewidth and the reflectivity. A 3 dB bandwidth as narrow as 10.5 MHz is observed with the Brillouin dynamic grating generated in a 9 m uniform fiber.

High-purity germanium crystal growing

International Nuclear Information System (INIS)

Hansen, W.L.; Haller, E.E.

1982-10-01

The germanium crystals used for the fabrication of nuclear radiation detectors are required to have a purity and crystalline perfection which is unsurpassed by any other solid material. These crystals should not have a net electrically active impurity concentration greater than 10 10 cm - 3 and be essentially free of charge trapping defects. Such perfect crystals of germanium can be grown only because of the highly favorable chemical and physical properties of this element. However, ten years of laboratory scale and commercial experience has still not made the production of such crystals routine. The origin and control of many impurities and electrically active defect complexes is now fairly well understood but regular production is often interrupted for long periods due to the difficulty of achieving the required high purity or to charge trapping in detectors made from crystals seemingly grown under the required conditions. The compromises involved in the selection of zone refining and crystal grower parts and ambients is discussed and the difficulty in controlling the purity of key elements in the process is emphasized. The consequences of growing in a hydrogen ambient are discussed in detail and it is shown how complexes of neutral defects produce electrically active centers

Radiochemical purity of Mo and Tc solution obtained after irradiation and dissolution of Mo-100-enriched and ultra-high-purity natural Mo disks

Energy Technology Data Exchange (ETDEWEB)

Tkac, Peter [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, Roman [Argonne National Lab. (ANL), Argonne, IL (United States); Chemerisov, Sergey D. [Argonne National Lab. (ANL), Argonne, IL (United States); Rotsch, David A. [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-09-01

Four irradiations of ultra-high-purity natural Mo targets and one irradiation using 97.4% Mo-100-enriched material were performed. The purpose of these irradiations was to determine whether the presence of Sn stabilizer in the H₂O₂ used for the dissolution of sintered Mo disks can affect the radiochemical purity of the final K₂MoO₄ in 5M KOH solution. Results from radiochemical purity tests performed using thin-layer paper chromatography show that even 2– 3× excess of Sn-stabilized H₂O₂ typically used for dissolution of sintered Mo disks did not affect the radiochemical purity of the final product.

Heterogeneously Integrated Microwave Signal Generators with Narrow Linewidth Lasers

Science.gov (United States)

2017-03-20

have shown that heterogeneous integration not only allows for a reduced cost due to economy of scale, but also allows for same or even better...advantage of introducing SOAs for microwave generator is the control and boosting of optical power before the detector providing higher RF powers. A

Determination of continuous variable entanglement by purity measurements.

Science.gov (United States)

Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio

2004-02-27

We classify the entanglement of two-mode Gaussian states according to their degree of total and partial mixedness. We derive exact bounds that determine maximally and minimally entangled states for fixed global and marginal purities. This characterization allows for an experimentally reliable estimate of continuous variable entanglement based on measurements of purity.

Steam purity in PWRs

International Nuclear Information System (INIS)

Hopkinson, J.; Passell, T.

1982-01-01

Reports that 2 EPRI studies of PWRs prove that impure steam triggers decay of turbine metals. Reveals that EPRI is attempting to improve steam monitoring and analysis, which are key steps on the way to deciding the most cost-effective degree of steam purity, and to upgrade demineralizing systems, which can then reliably maintain that degree of purity. Points out that 90% of all cracks in turbine disks have occurred at the dry-to-wet transition zone, dubbed the Wilson line. Explains that because even very clean water contains traces of chemical impurities with concentrations in the parts-per-billion range, Crystal River-3's secondary loop was designed with even more purification capability; a deaerator to remove oxygen and prevent oxidation of system metals, and full-flow resin beds to demineralize 100% of the secondary-loop water from the condenser. Concludes that focusing attention on steam and water chemistry can ward off cracking and sludge problems caused by corrosion

High-Purity Glasses Based on Arsenic Chalcogenides

Science.gov (United States)

2001-06-01

Chemical interaction of chalcogenides and some impurities (CS 2, TeO2 ) with the quartz glass at high temperature leads to the thin layers formation...UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADPO1 1523 TITLE: High-Purity Glasses Based on Arsenic Chalcogenides...Materials Vol. 3, No. 2, June 2001, p. 341 - 349 HIGH-PURITY GLASSES BASED ON ARSENIC CHALCOGENIDES M. F. Churbanov, I. V. Scripachev, G. E. Snopatin, V. S

Distributed seeding for narrow-line width hard x-ray free-electron lasers

Energy Technology Data Exchange (ETDEWEB)

Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Anisimov, Petr Mikhaylovich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Buechler, Cynthia Eileen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewellen, IV, John W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Marksteiner, Quinn R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-09-09

We describe a new FEL line-narrowing technique called distributed seeding (DS), using Si(111) Bragg crystal monochromators to enhance the spectral brightness of the MaRIE hard X-ray freeelectron laser. DS differs from self-seeding in three important aspects. First, DS relies on spectral filtering of the radiation at multiple locations along the undulator, with a monochromator located every few power gain lengths. Second, DS performs filtering early in the exponential gain region before SASE spikes start to appear in the radiation longitudinal profile. Third, DS provides the option to select a wavelength longer than the peak of the SASE gain curve, which leads to improved spectral contrast of the seeded FEL over the SASE background. Timedependent Genesis simulations show the power-vs-z growth curves for DS exhibit behaviors of a seeded FEL amplifier, such as exponential growth region immediately after the filters. Of the seeding approaches considered, the two-stage DS spectra produce the highest contrast of seeded FEL over the SASE background and that the three-stage DS provides the narrowest linewidth with a relative spectral FWHM of 8 X 10^-5 .

Dependence of EIA spectra on mutual coherence between coupling and probe fields in Cs atomic vapors

Energy Technology Data Exchange (ETDEWEB)

Kwon, Mi Rang; Kim, Kyoung Dae; Park, Hyun Deok; Kim, Jung Bog [Korea National University of Education, Chungwon (Korea, Republic of); Moon, Han Seb [Korea Research Institute of the Standards and Science, Taejon (Korea, Republic of)

2002-03-01

We observed the dependence of EIA spectra on the mutual coherence between the coupling and the probe fields in the D{sub 2}F{sub 9} = 4 {r_reversible} F{sub e} = 5 transition of Cs vapors at room temperature where the coupling and the probe fields were made from one laser source or two independent laser sources. By using one source having a high mutual coherence, we found EIA spectra linewidths much narrower than 0.1 {gamma} on the weak coupling field and the transparent spectra with linewidths narrower than 1 MHz within subnatural absorption on the strong coupling field. On the other hand, where the two sources which were nearly incoherent with each other were used, the absorption profiles showed the same dependence on the coupling power as the spectra for the one source, but their linewidths were broad, on the order of the natural linewidth.

Spectral control of an alexandrite laser for an airborne water-vapor differential absorption lidar system

Science.gov (United States)

Ponsardin, Patrick; Grossmann, Benoist E.; Browell, Edward V.

1994-01-01

A narrow-linewidth pulsed alexandrite laser has been greatly modified for improved spectral stability in an aircraft environment, and its operation has been evaluated in the laboratory for making water-vapor differential absorption lidar measurements. An alignment technique is described to achieve the optimum free spectral range ratio for the two etalons inserted in the alexandrite laser cavity, and the sensitivity of this ratio is analyzed. This technique drastically decreases the occurrence of mode hopping, which is commonly observed in a tunable, two-intracavity-etalon laser system. High spectral purity (greater than 99.85%) at 730 nm is demonstrated by the use of a water-vapor absorption line as a notch filter. The effective cross sections of 760-nm oxygen and 730-nm water-vapor absorption lines are measured at different pressures by using this laser, which has a finite linewidth of 0.02 cm(exp -1) (FWHM). It is found that for water-vapor absorption linewidths greater than 0.04 cm(exp -1) (HWHM), or for altitudes below 10 km, the laser line can be considered monochromatic because the measured effective absorption cross section is within 1% of the calculated monochromatic cross section. An analysis of the environmental sensitivity of the two intracavity etalons is presented, and a closed-loop computer control for active stabilization of the two intracavity etalons in the alexandrite laser is described. Using a water-vapor absorption line as a wavelength reference, we measure a long-term frequency drift (approximately 1.5 h) of less than 0.7 pm in the laboratory.

Measurement of carrier lifetime and linewidth enhancement factor for 1.5- mu m ridge-waveguide laser amplifier

DEFF Research Database (Denmark)

Storkfelt, Niels; Mikkelsen, B.; Olesen, D. S.

1991-01-01

Semiconductor optical amplifiers are used for investigation of the effective carrier lifetime and the linewidth enhancement factor. Contrary to semiconductor lasers, semiconductor optical amplifiers allow measurement at high levels of injected carrier density. The carrier lifetime and the linewid...

Method of high purity silane preparation

Science.gov (United States)

Tsuo, Y. Simon; Belov, Eugene P.; Gerlivanov, Vadim G.; Zadde, Vitali V.; Kleschevnikova, Solomonida I.; Korneev, Nikolai N.; Lebedev, Eugene N.; Pinov, Akhsarbek B.; Ryabenko, Eugene A.; Strebkov, Dmitry S.; Chernyshev, Eugene A.

2000-01-01

A process for the preparation of high purity silane, suitable for forming thin layer silicon structures in various semiconductor devices and high purity poly- and single crystal silicon for a variety of applications, is provided. Synthesis of high-purity silane starts with a temperature assisted reaction of metallurgical silicon with alcohol in the presence of a catalyst. Alcoxysilanes formed in the silicon-alcohol reaction are separated from other products and purified. Simultaneous reduction and oxidation of alcoxysilanes produces gaseous silane and liquid secondary products, including, active part of a catalyst, tetra-alcoxysilanes, and impurity compounds having silicon-hydrogen bonds. Silane is purified by an impurity adsorption technique. Unreacted alcohol is extracted and returned to the reaction with silicon. Concentrated mixture of alcoxysilanes undergoes simultaneous oxidation and reduction in the presence of a catalyst at the temperature -20.degree. C. to +40.degree. C. during 1 to 50 hours. Tetra-alcoxysilane extracted from liquid products of simultaneous oxidation and reduction reaction is directed to a complete hydrolysis. Complete hydrolysis of tetra-alcoxysilane results in formation of industrial silica sol and alcohol. Alcohol is dehydrated by tetra-alcoxysilane and returned to the reaction with silicon.

Preparation of high-purity cerium nitrate

International Nuclear Information System (INIS)

Avila, Daniela Moraes; Silva Queiroz, Carlos Alberto da; Santos Mucillo, Eliana Navarro dos

1995-01-01

The preparation of high-purity cerium nitrate has been carried out Cerium oxide has been prepared by fractioned precipitation and ionic exchange techniques, using a concentrate with approximately 85% of cerium oxide from NUCLEMON as raw material. Five sequential ion-exchange columns with a retention capacity of 170 g each have been used. The ethylenediamine-tetraacetic acid (EDTA) was used as eluent. The cerium content has been determined by gravimetry and iodometry techniques. The resulting cerium oxide has a purity > 99%. This material was transformed in cerium nitrate to be used as precursor for the preparation of Zirconia-ceria ceramics by the coprecipitation technique. (author)

High density nitrogen-vacancy sensing surface created via He{sup +} ion implantation of {sup 12}C diamond

Energy Technology Data Exchange (ETDEWEB)

Kleinsasser, Ed E., E-mail: edklein@uw.edu [Department of Electrical Engineering, University of Washington, Seattle, Washington 98195-2500 (United States); Stanfield, Matthew M.; Banks, Jannel K. Q. [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States); Zhu, Zhouyang; Li, Wen-Di [HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), Shenzhen 518000 (China); Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong (China); Acosta, Victor M. [Department of Physics and Astronomy, Center for High Technology Materials, University of New Mexico, Albuquerque, New Mexico 87106 (United States); Watanabe, Hideyuki [Correlated Electronics Group, Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8565 (Japan); Itoh, Kohei M. [School of Fundamental Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Fu, Kai-Mei C., E-mail: kaimeifu@uw.edu [Department of Electrical Engineering, University of Washington, Seattle, Washington 98195-2500 (United States); Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States)

2016-05-16

We present a promising method for creating high-density ensembles of nitrogen-vacancy centers with narrow spin-resonances for high-sensitivity magnetic imaging. Practically, narrow spin-resonance linewidths substantially reduce the optical and RF power requirements for ensemble-based sensing. The method combines isotope purified diamond growth, in situ nitrogen doping, and helium ion implantation to realize a 100 nm-thick sensing surface. The obtained 10{sup 17 }cm{sup −3} nitrogen-vacancy density is only a factor of 10 less than the highest densities reported to date, with an observed 200 kHz spin resonance linewidth over 10 times narrower.

Interaction of light with planar lattices of atoms: Reflection, transmission, and cooperative magnetometry

Science.gov (United States)

Facchinetti, G.; Ruostekoski, J.

2018-02-01

We study strong, light-mediated, resonant dipole-dipole interactions in two-dimensional planar lattices of cold atoms. We provide a detailed analysis for the description of the dipolar point emitter lattice plane as a "superatom" whose response is similar to electromagnetically induced transparency but which exhibits an ultranarrow collective size-dependent subradiant resonance linewidth. The superatom model provides intuitively simple descriptions for the spectral response of the array, including the complete reflection, full transmission, narrow Fano resonances, and asymptotic expressions for the resonance linewidths of the collective eigenmodes. We propose a protocol to transfer almost the entire radiative excitation to a single correlated subradiant eigenmode in a lattice and show that the medium obtained by stacked lattice arrays can form a cooperative magnetometer. Such a magnetometer utilizes similar principles as magnetometers based on the electromagnetically induced transparency. The accuracy of the cooperative magnetometer, however, is not limited by the single-atom resonance linewidth but the much narrower collective linewidth that results from the strong dipole-dipole interactions.

Effect of phosphorus on hot ductility of high purity iron

International Nuclear Information System (INIS)

Abiko, K.; Liu, C.M.; Ichikawa, M..; Suenaga, H.; Tanino, M.

1995-01-01

Tensile tests on high purity Fe-P alloys with 0, 0.05 and 0.1 mass%P were carried out at temperatures between 300 K and 1073 K to clarify the intrinsic effect of phosphorus on the mechanical properties of iron at elevated temperatures. Microstructures of as-quenched, interrupted and ruptured specimens were observed. Experimental results show that the addition of phosphorus causes a remarkable increase in proof stress of high purity iron at 300 K, but the increase in proof stress by phosphorus decreases with increasing test temperature. The strengthening effect of phosphorus reduces to zero at 1073 K. High purity iron and Fe-P alloys rupture at almost 100% reduction in area at the whole test temperatures. However, Fe-P alloys show much larger elongation at test temperatures above 773 K than high purity iron. The increased elongation of high purity iron by addition of phosphorus was shown to be related to the effect of phosphorus on dynamic recovery and recrystallization of iron as its intrinsic effect. (orig.)

Thermal and electrical conductivities of high purity tantalum

International Nuclear Information System (INIS)

Archer, S.L.

1978-01-01

The electrical resistivity and thermal conductivity of three high purity tantalum samples have been measured as functions of temperature over a temperature range of 5K to 65K. Sample purities ranged up to a resistivity ratio of 1714. The highest purity sample had a residual resistivity of .76 x 10 -10 OMEGA-m. The intrinsic resistivity varied as T 3 . 9 from 10K to 31K. The thermal conductivity of the purest sample had a maximum of 840 W/mK at 9.8K. The intrinsic thermal resistivity varied as T 2 . 4 from 10K to 35K. At low temperatures electrons were scattered primarily by impurities and by phonons with both interband and intraband transitions observed. The electrical and thermal resistivity is departed from Matthiessen's rule at low temperatures

Standing spin-wave mode structure and linewidth in partially disordered hexagonal arrays of perpendicularly magnetized sub-micron Permalloy discs

International Nuclear Information System (INIS)

Ross, N.; Kostylev, M.; Stamps, R. L.

2014-01-01

Standing spin wave mode frequencies and linewidths in partially disordered perpendicular magnetized arrays of sub-micron Permalloy discs are measured using broadband ferromagnetic resonance and compared to analytical results from a single, isolated disc. The measured mode structure qualitatively reproduces the structure expected from the theory. Fitted demagnetizing parameters decrease with increasing array disorder. The frequency difference between the first and second radial modes is found to be higher in the measured array systems than predicted by theory for an isolated disc. The relative frequencies between successive spin wave modes are unaffected by reduction of the long-range ordering of discs in the array. An increase in standing spin wave resonance linewidth at low applied magnetic fields is observed and grows more severe with increased array disorder.

15 W high OSNR kHz-linewidth linearly-polarized all-fiber single-frequency MOPA at 1.6 μm.

Science.gov (United States)

Yang, Changsheng; Guan, Xianchao; Zhao, Qilai; Lin, Wei; Li, Can; Gan, Jiulin; Qian, Qi; Feng, Zhouming; Yang, Zhongmin; Xu, Shanhui

2018-05-14

A 1603 nm high optical signal-to-noise ratio (OSNR) kHz-linewidth linearly-polarized all-fiber single-frequency master-oscillator power amplifier (MOPA) is demonstrated. To suppress the amplified spontaneous emission from Yb 3+ /Er 3+ ions with the customized filters and optimize the length of the double cladding active fiber, an over 15 W stable single-longitudinal-mode laser is achieved with an OSNR of >70 dB. A measured laser linewidth of 4.5 kHz and a polarization-extinction ratio of >23 dB are obtained at the full output power. This L-band high-power single-frequency MOPA is promising for high-resolution molecular spectroscopy and pumping of Tm 3+ -doped or Tm 3+ /Ho 3+ co-doped laser.

Fabrication of high quality anodic aluminum oxide (AAO) on low purity aluminum—A comparative study with the AAO produced on high purity aluminum

International Nuclear Information System (INIS)

Michalska-Domańska, Marta; Norek, Małgorzata; Stępniowski, Wojciech J.; Budner, Bogusław

2013-01-01

Highlights: • Nanoporous alumina was fabricated by anodization in sulfuric acid solution with glycol. • The AAO manufacturing on low- and high-purity Al was compared. • The pores size was ranging between 30 and 50 nm. • No difference in the quality of the AAO fabricated on both Al types was observed. • The current vs. anodization time curves were recorded. -- Abstract: In this work the quality, arrangement, composition, and regularity of nanoporous AAO formed on the low-purity (AA1050) and high-purity aluminum during two-step anodization in a mixture of sulfuric acid solution (0.3 M), water and glycol (3:2, v/v), at various voltages (15, 20, 25, 30, 35 V) and at temperature of −1 °C, are investigated. The electrochemical conditions have allowed to obtain pores with the size ranging from 30 to 50 nm, which are much larger than those usually obtained by anodization in a pure sulfuric acid solution (<20 nm). The mechanism of the AAO growth is discussed. It was found that with the increase of applied anodizing voltage a number of incorporated sulfate ions in the aluminum oxide matrix increases, which was connected with the appearance of an unusual area in the current vs. time curves. On the surface of anodizing low- and high-purity aluminum, the formation of hillocks was observed, which was associated with the sulfate ions incorporation. The sulfate ions are replacing the oxygen atom/atoms in the AAO amorphous crystal structure and, consequently, the AAO template swells, the oxide cracks and uplifts causing the formation of hillocks. The same mechanism occurs for both low- and high-purity aluminum. Nanoporous AAO characterized by a very high regularity, not registered previously for low purity aluminum, was obtained. Furthermore, no significant difference in the regularity ratio between the AAO obtained on low- and high-purity aluminum, was observed. The electrochemical conditions applied in this study can be, thus, used for the fabrication of high quality

Radioactive preparations. Determination of radiochemical purity by thin-layer chromatography

International Nuclear Information System (INIS)

1986-01-01

The standard sets the data which must be attached to every sample, and the equipment, chemicals and auxiliary substances used in the determination of radiochemical purity of substances by chromatography. Described are preparation of the sample, the procedure of sample deposition, the development, drying and detection of the radioactive preparation. The qualitative and quantitative assessment of the radiochromatogram is described as are the calculation of radiochemical purity and the determination of the reproducibility of measurement of radiochemical purity of radioactive preparations. (E.S.)

Purity of Gaussian states: Measurement schemes and time evolution in noisy channels

International Nuclear Information System (INIS)

Paris, Matteo G.A.; Illuminati, Fabrizio; Serafini, Alessio; De Siena, Silvio

2003-01-01

We present a systematic study of the purity for Gaussian states of single-mode continuous variable systems. We prove the connection of purity to observable quantities for these states, and show that the joint measurement of two conjugate quadratures is necessary and sufficient to determine the purity at any time. The statistical reliability and the range of applicability of the proposed measurement scheme are tested by means of Monte Carlo simulated experiments. We then consider the dynamics of purity in noisy channels. We derive an evolution equation for the purity of general Gaussian states both in thermal and in squeezed thermal baths. We show that purity is maximized at any given time for an initial coherent state evolving in a thermal bath, or for an initial squeezed state evolving in a squeezed thermal bath whose asymptotic squeezing is orthogonal to that of the input state

7 CFR 201.51b - Purity procedures for coated seed.

Science.gov (United States)

2010-01-01

... ACT FEDERAL SEED ACT REGULATIONS Purity Analysis in the Administration of the Act § 201.51b Purity...). Use of fine mesh sieves is recommended for this procedure, and stirring or shaking the coated units...

Phosphorus-31 MRI of bones using quadratic echo line-narrowing

Science.gov (United States)

Frey, Merideth; Barrett, Sean; Insogna, Karl; Vanhouten, Joshua

2012-02-01

There is a great need to probe the internal composition of bone on the sub-0.1 mm length scale, both to study normal features and to look for signs of disease. Despite the obvious importance of the mineral fraction to the biomechanical properties of skeletal tissue, few non-destructive techniques are available to evaluate changes in its chemical structure and functional microarchitecture on the interior of bones. MRI would be an excellent candidate, but bone is a particularly challenging tissue to study given the relatively low water density and wider linewidths of its solid components. Recent fundamental research in quantum computing gave rise to a new NMR pulse sequence - the quadratic echo - that can be used to narrow the broad NMR spectrum of solids. This offers a new route to do high spatial resolution, 3D ^31P MRI of bone that complements conventional MRI and x-ray based techniques to study bone physiology and structure. We have used our pulse sequence to do 3D ^31P MRI of ex vivo bones with a spatial resolution of (sub-450 μm)^3, limited only by the specifications of a conventional 4 Tesla liquid-state MRI system. We will describe our plans to push this technique towards the factor of 1000 increase in spatial resolution imposed by fundamental limits.

The Liquid Argon Purity Demonstrator

Energy Technology Data Exchange (ETDEWEB)

Adamowski, M.; Carls, B.; Dvorak, E.; Hahn, A.; Jaskierny, W.; Johnson, C.; Jostlein, H.; Kendziora, C.; Lockwitz, S.; Pahlka, B.; Plunkett, R.; Pordes, S.; Rebel, B.; Schmitt, R.; Stancari, M.; Tope, T.; Voirin, E.; Yang, T.

2014-07-01

The Liquid Argon Purity Demonstrator was an R&D test stand designed to determine if electron drift lifetimes adequate for large neutrino detectors could be achieved without first evacuating the cryostat. We describe here the cryogenic system, its operations, and the apparatus used to determine the contaminant levels in the argon and to measure the electron drift lifetime. The liquid purity obtained by this system was facilitated by a gaseous argon purge. Additionally, gaseous impurities from the ullage were prevented from entering the liquid at the gas-liquid interface by condensing the gas and filtering the resulting liquid before returning to the cryostat. The measured electron drift lifetime in this test was greater than 6 ms, sustained over several periods of many weeks. Measurements of the temperature profile in the argon, to assess convective flow and boiling, were also made and are compared to simulation.

Single-mode surface plasmon distributed feedback lasers.

Science.gov (United States)

Karami Keshmarzi, Elham; Tait, R Niall; Berini, Pierre

2018-03-29

Single-mode surface plasmon distributed feedback (DFB) lasers are realized in the near infrared using a two-dimensional non-uniform long-range surface plasmon polariton structure. The surface plasmon mode is excited onto a 20 nm-thick, 1 μm-wide metal stripe (Ag or Au) on a silica substrate, where the stripe is stepped in width periodically, forming a 1st order Bragg grating. Optical gain is provided by optically pumping a 450 nm-thick IR-140 doped PMMA layer as the top cladding, which covers the entire length of the Bragg grating, thus creating a DFB laser. Single-mode lasing peaks of very narrow linewidth were observed for Ag and Au DFBs near 882 nm at room temperature. The narrow linewidths are explained by the low spontaneous emission rate into the surface plasmon lasing mode as well as the high quality factor of the DFB structure. The lasing emission is exclusively TM polarized. Kinks in light-light curves accompanied by spectrum narrowing were observed, from which threshold pump power densities can be clearly identified (0.78 MW cm-2 and 1.04 MW cm-2 for Ag and Au DFB lasers, respectively). The Schawlow-Townes linewidth for our Ag and Au DFB lasers is estimated and very narrow linewidths are predicted for the lasers. The lasers are suitable as inexpensive, recyclable and highly coherent sources of surface plasmons, or for integration with other surface plasmon elements of similar structure.

Purity and adulterant analysis of crack seizures in Brazil.

Science.gov (United States)

Fukushima, André R; Carvalho, Virginia M; Carvalho, Débora G; Diaz, Ernesto; Bustillos, Jose Oscar William Vega; Spinosa, Helenice de S; Chasin, Alice A M

2014-10-01

Cocaine represents a serious problem to society. Smoked cocaine is very addictive and it is frequently associated with violence and health issues. Knowledge of the purity and adulterants present in seized cocaine, as well as variations in drug characteristics are useful to identify drug source and estimate health impact. No data are available regarding smoked cocaine composition in most countries, and the smoked form is increasing in the Brazilian market. The purpose of the present study is to contribute to the current knowledge on the status of crack cocaine seized samples on the illicit market by the police of São Paulo. Thus, 404 samples obtained from street seizures conducted by the police were examined. The specimens were macroscopically characterized by color, form, odor, purity, and adulterant type, as well as smoke composition. Samples were screened for cocaine using modified Scott test and thin-layer chromatographic (TLC) technique. Analyses of purity and adulterants were performed with gas chromatography equipped with flame ionization detector (GC-FID). Additionally, smoke composition was analyzed by GC-mass spectrometry (MS), after samples burning. Samples showed different colors and forms, the majority of which is yellow (74.0%) or white (20.0%). Samples free of adulterants represented 76.3% of the total. Mean purity of the analyzed drug was 71.3%. Crack cocaine presented no correlations between macroscopic characteristics and purity. Smoke analysis showed compounds found also in the degradation of diesel and gasoline. Therefore, the drug marketed as crack cocaine in São Paulo has similar characteristics to coca paste. High purity can represent a greater risk of dependency and smoke compounds are possibly worsening drug health impact. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Purity Evaluation of Single-Walled Carbon Nanotubes Using Thermogravimetric Analysis

International Nuclear Information System (INIS)

Goak, Jeung Choon; Kim, Tae Yang; Jung, Jongwan; Seo, Young-Soo; Lee, Naesung; Sok, Junghyun

2013-01-01

This study evaluated the purity of single-walled carbon nanotubes (SWCNTs) in the arc-synthesized SWCNT samples by using thermogravimetric analysis (TGA). The as-produced SWCNT samples were heat-treated in air for 20 h at 275-475°C and characterized by scanning and transmission electron microscopes and TGA to establish oxidation temperature ranges of SWCNTs and carbonaceous impurities comprising the samples. Based on these oxidation temperature ranges, derivative thermogravimetric curves were deconvoluted, and differentiated peaks were assigned to SWCNTs and carbonaceous impurities. The compositions and the SWCNT purities of the samples were obtained simply by calculating the areal ratios under the deconvoluted curves. TGA studies on purity evaluation and thermal stabilities of SWCNTs and carbonaceous impurities are likely to provide us with a simple route of thermal oxidation purification to acquire high-purity SWCNT samples.

Superconducting radio-frequency cavities made from medium and low-purity niobium ingots

Science.gov (United States)

Ciovati, Gianluigi; Dhakal, Pashupati; Myneni, Ganapati R.

2016-06-01

Superconducting radio-frequency cavities made of ingot niobium with residual resistivity ratio (RRR) greater than 250 have proven to have similar or better performance than fine-grain Nb cavities of the same purity, after standard processing. The high purity requirement contributes to the high cost of the material. As superconducting accelerators operating in continuous-wave typically require cavities to operate at moderate accelerating gradients, using lower purity material could be advantageous not only to reduce cost but also to achieve higher Q 0-values. In this contribution we present the results from cryogenic RF tests of 1.3-1.5 GHz single-cell cavities made of ingot Nb of medium (RRR = 100-150) and low (RRR = 60) purity from different suppliers. Cavities made of medium-purity ingots routinely achieved peak surface magnetic field values greater than 70 mT with an average Q 0-value of 2 × 1010 at 2 K after standard processing treatments. The performances of cavities made of low-purity ingots were affected by significant pitting of the surface after chemical etching.

Millimeter-wave response and linewidth of Josephson oscillations in YBa2Cu3O7 step-edge junctions

DEFF Research Database (Denmark)

Divin, Yu. Ya.; Andreev, A. V.; Fischer, Gerd Michael

1993-01-01

by thermal fluctuations at liquid nitrogen temperatures. At lower temperatures the observed linewidth increases indicating that low-frequency fluctuations become dominant in the junction as the temperature is reduced. Due to an inhomogeneous spatial distribution of the current the step-edge junction might...

Entanglement and purity of two-mode Gaussian states in noisy channels

International Nuclear Information System (INIS)

Serafini, Alessio; Illuminati, Fabrizio; De Siena, Silvio; Paris, Matteo G.A.

2004-01-01

We study the evolution of purity, entanglement, and total correlations of general two-mode continuous variable Gaussian states in arbitrary uncorrelated Gaussian environments. The time evolution of purity, von Neumann entropy, logarithmic negativity, and mutual information is analyzed for a wide range of initial conditions. In general, we find that a local squeezing of the bath leads to a faster degradation of purity and entanglement, while it can help to preserve the mutual information between the modes

Ultranarrow-bandwidth filter based on a thermal EIT medium.

Science.gov (United States)

Wang, Gang; Wang, Yu-Sheng; Huang, Emily Kay; Hung, Weilun; Chao, Kai-Lin; Wu, Ping-Yeh; Chen, Yi-Hsin; Yu, Ite A

2018-05-21

We present high-contrast electromagnetically-induced-transparency (EIT) spectra in a heated vapor cell of single isotope 87 Rb atoms. The EIT spectrum has both high resonant transmission up to 67% and narrow linewidth of 1.1 MHz. We get rid of the possible amplification resulted from the effects of amplification without population inversion and four-wave mixing. Therefore, this high transmitted light is not artificial. The theoretical prediction of the probe transmission agrees well with the data and the experimental parameters can be derived reasonably from the model. Such narrow and high-contrast spectral profile can be employed as a high precision bandpass filter, which provides a significant advantage in terms of stability and tunability. The central frequency tuning range of the filter is larger than 100 MHz with out-of-band blocking ≥15 dB. This bandpass filter can effectively produce light fields with subnatural linewidth. Nonlinearity associating with the narrow-linewidth and high-contrast EIT profile can be very useful in the applications utilizing the EIT effect.

Generation of 103 fs mode-locked pulses by a gain linewidth-variable Nd,Y:CaF2 disordered crystal.

Science.gov (United States)

Qin, Z P; Xie, G Q; Ma, J; Ge, W Y; Yuan, P; Qian, L J; Su, L B; Jiang, D P; Ma, F K; Zhang, Q; Cao, Y X; Xu, J

2014-04-01

We have demonstrated a diode-pumped passively mode-locked femtosecond Nd,Y:CaF2 disordered crystal laser for the first time to our knowledge. By choosing appropriate Y-doping concentration, a broad fluorescence linewidth of 31 nm has been obtained from the gain linewidth-variable Nd,Y:CaF2 crystal. With the Nd,Y:CaF2 disordered crystal as gain medium, the mode-locked laser generated pulses with pulse duration as short as 103 fs, average output power of 89 mW, and repetition rate of 100 MHz. To our best knowledge, this is the shortest pulse generated from Nd-doped crystal lasers so far. The research results show that the Nd,Y:CaF2 disordered crystal will be a potential alternative as gain medium of repetitive chirped pulse amplification for high-peak-power lasers.

Superconducting radio-frequency cavities made from medium and low-purity niobium ingots

International Nuclear Information System (INIS)

Ciovati, Gianluigi; Dhakal, Pashupati; Myneni, Ganapati R

2016-01-01

Superconducting radio-frequency cavities made of ingot niobium with residual resistivity ratio (RRR) greater than 250 have proven to have similar or better performance than fine-grain Nb cavities of the same purity, after standard processing. The high purity requirement contributes to the high cost of the material. As superconducting accelerators operating in continuous-wave typically require cavities to operate at moderate accelerating gradients, using lower purity material could be advantageous not only to reduce cost but also to achieve higher Q 0 -values. In this contribution we present the results from cryogenic RF tests of 1.3–1.5 GHz single-cell cavities made of ingot Nb of medium (RRR = 100–150) and low (RRR = 60) purity from different suppliers. Cavities made of medium-purity ingots routinely achieved peak surface magnetic field values greater than 70 mT with an average Q 0 -value of 2 × 10 10 at 2 K after standard processing treatments. The performances of cavities made of low-purity ingots were affected by significant pitting of the surface after chemical etching. (paper)

Analytical monitoring of systems for the production of high-purity, desalinated water

International Nuclear Information System (INIS)

Kunert, I.

1988-01-01

The purity requirements to be met by high-purity water currently push the most sensitive analytical methods to their utmost limits of sensitivity. The required degree of purity of the water at present can only be achieved by application of membrane processes, and pre-purification of the feedwater to a quality corresponding to that of the raw water source. The contribution in hand discusses the analytical monitoring of the raw water treatment plant, the water treatment prior to the treatment by reverse osmosis, monitoring and control of the modules for reverse osmosis, and the monitoring of high-purity water production for the microelectronics industry. (orig./RB) [de

Gain-dependent linewidth enhancement factor in the quantum dot structures

Energy Technology Data Exchange (ETDEWEB)

Kim, Kyoung Chan; Han, Il Ki; Lee, Jung Il [Nano Device Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Kim, Tae Geun, E-mail: hikoel@kist.re.kr, E-mail: tgkim1@korea.ac.kr [School of Electrical Engineering, Korea University, Seoul 136-701 (Korea, Republic of)

2010-04-02

We measured the linewidth enhancement factor ({alpha} factor) of InAs quantum dot (QD) laser diodes (LDs) with two different QD structures. One is a normal QD LD with the same energy bandgap for each active QD layer, while the other is chirped with different energy bandgaps. The differential gain of the chirped InAs QD LDs is found to be about five times smaller than that of normal InAs QD LDs, whereas no overall wavelength shift with injection currents is observed in both QD LDs. The {alpha} factor is approximately five times higher in the chirped InAs QD LDs than in the normal InAs QD LDs. This relatively large {alpha} factor in the chirped InAs QD LDs is attributed to the asymmetrical, wide inhomogeneous gain profile.

Purity and surface roughness of vacuum deposited aluminium films

Energy Technology Data Exchange (ETDEWEB)

Dhere, N G; Arsenio, T P [Instituto Militar de Engenharia, Rio de Janeiro (Brazil); Patnaik, B K [Pontificia Universidade Catolica do Rio de Janeiro (Brazil). Instituto de Fisica; Assuncao, F C.R.; de Souza, A M [Pontificia Universidade Catolica do Rio de Janeiro (Brazil). Departamento de Ciencia dos Materiais e Metalurgia

1975-04-01

The authors studied the purity, surface roughness and grain size of vacuum-deposited aluminium films, using an intermetallic crucible and a continuous feed of pure aluminium wire. The grain size and roughness were studied by electron difraction, X-ray diffraction and the scanning electron microscope. Purity was determined by X-ray fluorescence produced by proton bombardment in the Van de Graaff accelerator and by X-ray and optical emission spectrometry.

High-purity aluminium creep under high hydrostatic pressure

International Nuclear Information System (INIS)

Zajtsev, V.I.; Lyafer, E.I.; Tokij, V.V.

1977-01-01

The effect of the hydrostatic pressure on the rate of steady-state creep of high-purity aluminium was investigated. It is shown that the hydrostatic pressure inhibits the creep. The activation volume of the creep is independent of the direction in the range of (4.7-6.2) kg/mm 2 and of the pressure in the range of (1-7.8000) atm. It is concluded that self-diffusion does not control the creep of high-purity aluminium at room temperature in the investigated stress and pressure range

OPACITY BROADENING OF {sup 13}CO LINEWIDTHS AND ITS EFFECT ON THE VARIANCE-SONIC MACH NUMBER RELATION

Energy Technology Data Exchange (ETDEWEB)

Correia, C.; De Medeiros, J. R. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59072-970 (Brazil); Burkhart, B.; Lazarian, A. [Astronomy Department, University of Wisconsin, Madison, 475 North Charter Street, WI 53711 (United States); Ossenkopf, V.; Stutzki, J. [Physikalisches Institut der Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln (Germany); Kainulainen, J. [Max-Planck-Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Kowal, G., E-mail: caioftc@dfte.ufrn.br [Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, 05508-090 (Brazil)

2014-04-10

We study how the estimation of the sonic Mach number (M{sub s} ) from {sup 13}CO linewidths relates to the actual three-dimensional sonic Mach number. For this purpose we analyze MHD simulations that include post-processing to take radiative transfer effects into account. As expected, we find very good agreement between the linewidth estimated sonic Mach number and the actual sonic Mach number of the simulations for optically thin tracers. However, we find that opacity broadening causes M{sub s} to be overestimated by a factor of ≈1.16-1.3 when calculated from optically thick {sup 13}CO lines. We also find that there is a dependence on the magnetic field: super-Alfvénic turbulence shows increased line broadening compared with sub-Alfvénic turbulence for all values of optical depth for supersonic turbulence. Our results have implications for the observationally derived sonic Mach number-density standard deviation (σ{sub ρ/(ρ)}) relationship, σ{sub ρ/〈ρ〉}{sup 2}=b{sup 2}M{sub s}{sup 2}, and the related column density standard deviation (σ {sub N/(N)}) sonic Mach number relationship. In particular, we find that the parameter b, as an indicator of solenoidal versus compressive driving, will be underestimated as a result of opacity broadening. We compare the σ {sub N/(N)}-M{sub s} relation derived from synthetic dust extinction maps and {sup 13}CO linewidths with recent observational studies and find that solenoidally driven MHD turbulence simulations have values of σ {sub N/(N)}which are lower than real molecular clouds. This may be due to the influence of self-gravity which should be included in simulations of molecular cloud dynamics.

Purity Evaluation of Bulk Single Wall Carbon Nanotube Materials

International Nuclear Information System (INIS)

Dettlaff-Weglikowska, U.; Hornbostel, B.; Cech, J.; Roth, S.; Wang, J.; Liang, J.

2005-01-01

We report on our experience using a preliminary protocol for quality control of bulk single wall carbon nanotube (SWNT) materials produced by the electric arc-discharge and laser ablation method. The first step in the characterization of the bulk material is mechanical homogenization. Quantitative evaluation of purity has been performed using a previously reported procedure based on solution phase near-infrared spectroscopy. Our results confirm that this method is reliable in determining the nanotube content in the arc-discharge sample containing carbonaceous impurities (amorphous carbon and graphitic particles). However, the application of this method to laser ablation samples gives a relative purity value over 100 %. The possible reason for that might be different extinction coefficient meaning different oscillator strength of the laser ablation tubes. At the present time, a 100 % pure reference sample of laser ablation SWNT is not available, so we chose to adopt the sample showing the highest purity as a new reference sample for a quantitative purity evaluation of laser ablation materials. The graphitic part of the carbonaceous impurities has been estimated using X-ray diffraction of 1:1 mixture of nanotube material and C60 as an internal reference. To evaluate the metallic impurities in the as prepared and homogenized carbon nanotube soot inductive coupled plasma (ICP) has been used

Growth of high purity semiconductor epitaxial layers by liquid phase ...

Indian Academy of Sciences (India)

Unknown

semiconductor materials in high purity form by liquid phase epitaxy (LPE) technique. Various possible sources of impurities in such ... reference to the growth of GaAs layers. The technique of growing very high purity layers ... the inner walls of the gas lines and (e) the containers for storing, handling and cleaning of the mate-.

Purity and Defect Characterization of Single-Wall Carbon Nanotubes Using Raman Spectroscopy

Directory of Open Access Journals (Sweden)

Yasumitsu Miyata

2011-01-01

Full Text Available We investigated the purity and defects of single-wall carbon nanotubes (SWCNTs produced by various synthetic methods including chemical vapor deposition, arc discharge, and laser ablation. The SWCNT samples were characterized using scanning electron microscopy (SEM, thermogravimetric analysis (TGA, and Raman spectroscopy. Quantitative analysis of SEM images suggested that the G-band Raman intensity serves as an index for the purity. By contrast, the intensity ratio of G-band to D-band (G/D ratio reflects both the purity and the defect density of SWCNTs. The combination of G-band intensity and G/D ratio is useful for a quick, nondestructive evaluation of the purity and defect density of a SWCNT sample.

Inter-comb synchronization by mode-to-mode locking

Science.gov (United States)

Chun, Byung Jae; Kim, Young-Jin; Kim, Seung-Woo

2016-08-01

Two combs of fiber femtosecond lasers are synchronized through the optical frequency reference created by injection-locking of a diode laser to a single comb mode. Maintaining a mHz-level narrow linewidth, the optical frequency reference permits two combs to be stabilized by mode-to-mode locking with a relative stability of 1.52  ×  10-16 at 10 s with a frequency slip of 2.46 mHz. This inter-comb synchronization can be utilized for applications such as dual-comb spectroscopy or ultra-short pulse synthesis without extra narrow-linewidth lasers.

Fluorescence and Four-Wave Mixing in Electromagnetically Induced Transparency Windows

International Nuclear Information System (INIS)

Wang Zhi-Guo; Li Cheng; Zhang Zhao-Yang; Che Jun-Ling; Qin Meng-Zhe; He Jia-Nan; Zhang Yan-Peng

2013-01-01

We simultaneously compare the probe transmission, Four-Wave Mixing (FWM) and fluorescence signals with dressing effects in a four-level atomic system. The variation rules of three types of signals are exhibited by changing the frequency detuning and power of incident laser beams. The interplay between two ladder subsystems is investigated in the Y-type atomic system. In particular, the fluorescence signal with ultra-narrow linewidth is obtained due to being sheared twice by the electromagnetically induced transparency window. Such fluorescence with very high coherence and monochromaticity can be used for the quantum correlation and narrow linewidth laser

High purity in steels as a criterion for materials development

International Nuclear Information System (INIS)

Jacobi, H.

1995-01-01

This summarizing report discusses the materials and application prospects for higher purity in steels, which will make possible further advances in materials behaviour and workability. Improvements in purity and homogeneity permit in particular more rational production of thin foils and wire, one-piece shaping of complicated bodywork components and the drawing, wall-ironing and flanging of two-piece beverage cans. Welded designs in plant and mechanical engineering can be fabricated with less effort and less weight. Difficult component geometries and shaping processes can be more easily mastered. Steels with optimized fracture toughness can be exposed to more extreme loads at even lower temperatures: applications worthy of mention include offshore engineering and large-diameter linepipes for use in arctic regions and at great underwater depths. Liquefied-gas transport vessels can be made more resistant to brittle rupture. The bending fatigue strength and service-life of valve-spring and rolling-bearing steels can be significantly increased. High-purity surfaces on piston rods and cylinders guarantee reliability in hydraulic systems, and high-purity calendering rolls permit defect-free embossing of paper surfaces. (orig.)

Activation analysis of high purity metals and application to study on physical properties

International Nuclear Information System (INIS)

Ueda, Yoshitake; Hashimoto, Eiji; Matsushita, Rokuji.

1994-01-01

In order to determine the true characteristics of matters, the utmost reduction of impurities is indispensable. By the heightening of the purity of aluminum, that of 99.9999% purity has been obtained, but efforts have been exerted to further heighten the purity. For the purpose, it is important to know the behavior of trace impurities during refining, and the quantitative research by neutron activation analysis for various impurities has been carried out. The research on the electron condition of trace impurity atoms in refined aluminum is also important. The band refining of high purity aluminum is explained. By repeating the refining 10 times, the sample of RRR exceeding 30000 was obtained. The impurities contributing to the resistivity are Sc, Ti, V and Cr. Based on the results, the heightening of aluminum purity was attempted by devising the new procedure. As for the electric properties of solute elements in high purity metals, those of transition elements and rare earth elements in aluminum are reported. As the result of measuring the remaining resistance, the sample having the RRR exceeding 45000 after the correction for size effect was done has been obtained. At present, the efforts toward further high purity are continued. (K.I.)

Low-cost high purity production

Science.gov (United States)

Kapur, V. K.

1978-01-01

Economical process produces high-purity silicon crystals suitable for use in solar cells. Reaction is strongly exothermic and can be initiated at relatively low temperature, making it potentially suitable for development into low-cost commercial process. Important advantages include exothermic character and comparatively low process temperatures. These could lead to significant savings in equipment and energy costs.

On the purity assessment of solid sodium borohydride

Science.gov (United States)

Botasini, Santiago; Méndez, Eduardo

2012-01-01

Since sodium borohydride has become extensively used as chemical hydrogen storage material in fuel cells, many techniques have been proposed to assess the purity of this substance. However, all of them are developed in aqueous media, where the reagent is unstable. In addition, its hygroscopic nature was difficults in any attempt to make precise quantifications. The present work compares three different methods, namely, voltammetric, titrimetric, and Fourier transformed infrared spectroscopy (FTIR) in order to assess the purity of sodium borohydride, using an expired and a new sodium borohydride samples as references. Our results show that only the FTIR measurements provide a simple and semi-quantitative means to assess the purity of sodium borohydride due to the fact that it is the only one that measures the sample in the solid state. A comparison between the experimental data and theoretical calculation reveals the identification of the absorption bands at 1437 cm-1 of sodium metaborate and 2291 cm-1 of sodium borohydride which represent a good fingerprint for the qualitative assessment of the sample quality.

Pump spectral linewidth influence on stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS) and self-termination behavior of SRS in liquids

Energy Technology Data Exchange (ETDEWEB)

He, Guang S.; Kuzmin, Andrey; Prasad, Paras N. [The Institute for Lasers, Photonics and Biophotonics, State University of New York, Buffalo, NY (United States)

2016-12-15

The threshold, temporal behavior, and conversion efficiency of stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SBS) in three liquids (benzene, hexane, and dimethyl sulfoxide) and two crystals (calcite and barium nitrate) have been investigated under three largely different spectral linewidth conditions. Pumped with 532-nm and nanosecond duration laser pulses of ≤ 0.01 cm{sup -1} linewidth, only SBS can be generated in all tested liquids with a high nonlinear reflectivity. However when the pump spectral linewidth is ∝0.07 cm{sup -1} or ∝0.8 cm{sup -1}, both SBS and SRS can be observed in benzene while only SRS can be generated in dimethyl sulfoxide; in all these cases SRS is the dominant contribution to the stimulated scattering but the efficiency values are drastically decreased due to the self-termination behavior of SRS in liquids, which arises from the thermal self-defocusing of both pump beam and SRS beam owing to Stokes-shift related opto-heating effect. In contrast, for SRS process in the two crystals, the thermal self-defocusing influence is negligible benefitting from their much greater thermal conductivity, and a higher conversion efficiency of SRS generation can be retained under all three pump conditions. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Perspectives of data-driven LPV modeling of high-purity distillation columns

NARCIS (Netherlands)

Bachnas, A.A.; Toth, R.; Mesbah, A.; Ludlage, J.H.A.

2013-01-01

Abstract—This paper investigates data-driven, Linear- Parameter-Varying (LPV) modeling of a high-purity distillation column. Two LPV modeling approaches are studied: a local approach, corresponding to the interpolation of Linear Time- Invariant (LTI) models identified at steady-state purity levels,

Submonolayer InGaAs/GaAs quantum-dot lasers with high modal gain and zero-linewidth enhancement factor

DEFF Research Database (Denmark)

Xu, Zhangcheng; Birkedal, Dan; Juhl, Michael

2004-01-01

.1 nm. When the injection current is about 0.98 times the threshold, the gain spectrum becomes symmetric with respect to the lasing wavelength, and zero-linewidth enhancement factor is observed. These properties are attributed to the high density and the high uniformity of SML QDs in our laser diode....

Determination of radiochemical purity using gas chromatography

International Nuclear Information System (INIS)

1975-01-01

The concepts of chromatography, gas chromatography, activity, radiochemical impurity are defined; the procedure of the application of gas chromatography for detecting radiochemical purity of substances is standardized. (E.F.)

Animal Sex: Purity Education and the Naturalization of the Abstinence Agenda

Science.gov (United States)

Sethna, Christabelle

2010-01-01

An early-twentieth-century movement for social purity in England, Canada and the United States aimed to eradicate prostitution, the double standard of sexual morals and their dreaded corollary, the venereal diseases. Social purists suggested that "purity education" for children was the best pedagogical prophylaxis against such…

Disgust sensitivity is primarily associated with purity-based moral judgments.

Science.gov (United States)

Wagemans, Fieke M A; Brandt, Mark J; Zeelenberg, Marcel

2018-03-01

Individual differences in disgust sensitivity are associated with a range of judgments and attitudes related to the moral domain. Some perspectives suggest that the association between disgust sensitivity and moral judgments will be equally strong across all moral domains (i.e., purity, authority, loyalty, care, fairness, and liberty). Other perspectives predict that disgust sensitivity is primarily associated with judgments of specific moral domains (e.g., primarily purity). However, no study has systematically tested if disgust sensitivity is associated with moral judgments of the purity domain specifically, more generally to moral judgments of the binding moral domains, or to moral judgments of all of the moral domains equally. Across 5 studies (total N = 1,104), we find consistent evidence for the notion that disgust sensitivity relates more strongly to moral condemnation of purity-based transgressions (meta-analytic r = .40) than to moral condemnation of transgressions of any of the other domains (range meta-analytic rs: .07-.27). Our findings are in line with predictions from Moral Foundations Theory, which predicts that personality characteristics like disgust sensitivity make people more sensitive to a certain set of moral issues. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Monitoring the Microbial Purity of the Treated Water and Dialysate

Directory of Open Access Journals (Sweden)

Canaud Bernard

2001-01-01

Full Text Available Dialysate purity has become a major concern in recent years since it has been proven that contamination of dialysate is able to induce the production of proinflammatory cytokines, putatively implicated in the development of dialysis related pathology. In order to reduce this risk, it is advised to use ultrapure dialysate as a new standard of dialysate purity. Ultrapure dialysate preparation may be easily achieved with modern water treatment technologies. The reliable production of ultrapure dialysate requires several prerequisites: use of ultrapure water, use of clean electrolytic concentrates, implementation of ultrafilters in the dialysate pathway to ensure cold sterilization of the fresh dialysate. The regular supply with such high-grade purity dialysate relies on predefined microbiological monitoring of the chain using adequate and sensitive methods, and hygienic handling including frequent disinfection to reduce the level of contamination and to prevent biofilm formation. Reliability of this process requires compliance with a very strict quality assurance process. In this paper, we summarized the principles of the dialysate purity monitoring and the criteria used for surveillance in order to establish good antimicrobial practices in dialysis.

1 Tb/s x km multimode fiber link combining WDM transmission and low-linewidth lasers.

Science.gov (United States)

Gasulla, I; Capmany, J

2008-05-26

We have successfully demonstrated an error-free transmission of 10 x 20 Gb/s 200 GHz-spaced ITU channels through a 5 km link of 62.5-microm core-diameter graded-index multimode silica fiber. The overall figure corresponds to an aggregate bit rate per length product of 1 Tb/s x km, the highest value ever reported to our knowledge. Successful transmission is achieved by a combination of low-linewidth DFB lasers and the central launch technique.

Synthesis of High Purity Nonsymmetric Dialkylphosphinic Acid Extractants.

Science.gov (United States)

Wang, Junlian; Xie, Meiying; Liu, Xinyu; Xu, Shengming

2017-10-19

We present the synthesis of (2,3-dimethylbutyl)(2,4,4'-trimethylpentyl)phosphinic acid as an example to demonstrate a method for the synthesis of high purity nonsymmetric dialkylphosphinic acid extractants. Low toxic sodium hypophosphite was chosen as the phosphorus source to react with olefin A (2,3-dimethyl-1-butene) to generate a monoalkylphosphinic acid intermediate. Amantadine was adopted to remove the dialkylphosphinic acid byproduct, as only the monoalkylphosphinic acid can react with amantadine to form an amantadine∙mono-alkylphosphinic acid salt, while the dialkylphosphinic acid cannot react with amantadine due to its large steric hindrance. The purified monoalkylphosphinic acid was then reacted with olefin B (diisobutylene) to yield nonsymmetric dialkylphosphinic acid (NSDAPA). The unreacted monoalkylphosphinic acid can be easily removed by a simple base-acid post-treatment and other organic impurities can be separated out through the precipitation of the cobalt salt. The structure of the (2,3-dimethylbutyl)(2,4,4'-trimethylpentyl)phosphinic acid was confirmed by 31 P NMR, 1 H NMR, ESI-MS, and FT-IR. The purity was determined by a potentiometric titration method, and the results indicate that the purity can exceed 96%.

The dynamic characteristics and linewidth enhancement factor of quasi-supercontinuum self-assembled quantum dot lasers

KAUST Repository

Tan, Cheeloon

2009-09-01

The theoretical analysis of optical gain and chirp characteristics of a semiconductor quantum dot (Qdot) broadband laser is presented. The model based on population rate equations, has been developed to investigate the multiple states lasing or quasi-supercontinuum lasing in InGaAs/GaAs Qdot laser. The model takes into account factors such as Qdot size fluctuation, finite carrier lifetime in each confined energy states, wetting layer induced nonconfined states and the presence of continuum states. Hence, calculation of the linewidth enhancement factor together with the variation of optical gain and index change across the spectrum of interest becomes critical to yield a basic understanding on the limitation of this new class of lasers. Such findings are important for the design of a practical single broadband laser diode for applications in low coherence interferometry sensing and optical fiber communications. Calculation results show that the linewidth enhancement factor from the ground state of broadband Qdot lasers (α ∼ 3) is slightly larger but in the same order of magnitude as compared to that of conventional Qdot lasers. The gain spectrum of the quasi-supercontinuum lasing system exhibits almost twice the bandwidth than conventional lasers but with comparable material differential gain (∼ 10-16 cm2) and material differential refractive index (∼ 10sup>-20 cm3 ) near current threshold. © 2009 IEEE.

The dynamic characteristics and linewidth enhancement factor of quasi-supercontinuum self-assembled quantum dot lasers

KAUST Repository

Tan, Cheeloon; Wang, Yang; Djie, Hery Susanto; Ooi, Boon S.

2009-01-01

The theoretical analysis of optical gain and chirp characteristics of a semiconductor quantum dot (Qdot) broadband laser is presented. The model based on population rate equations, has been developed to investigate the multiple states lasing or quasi-supercontinuum lasing in InGaAs/GaAs Qdot laser. The model takes into account factors such as Qdot size fluctuation, finite carrier lifetime in each confined energy states, wetting layer induced nonconfined states and the presence of continuum states. Hence, calculation of the linewidth enhancement factor together with the variation of optical gain and index change across the spectrum of interest becomes critical to yield a basic understanding on the limitation of this new class of lasers. Such findings are important for the design of a practical single broadband laser diode for applications in low coherence interferometry sensing and optical fiber communications. Calculation results show that the linewidth enhancement factor from the ground state of broadband Qdot lasers (α ∼ 3) is slightly larger but in the same order of magnitude as compared to that of conventional Qdot lasers. The gain spectrum of the quasi-supercontinuum lasing system exhibits almost twice the bandwidth than conventional lasers but with comparable material differential gain (∼ 10-16 cm2) and material differential refractive index (∼ 10sup>-20 cm3 ) near current threshold. © 2009 IEEE.

Recovery of high-purity hydrogen from COG

Energy Technology Data Exchange (ETDEWEB)

Tsukiyama, Y

1982-01-01

A general account of the latest trends in the recovery of high-purity hydrogen from coke oven gas (COG), the article being based on both Japanese and overseas literature: 1) Deep-freeze separation: impurities are liquefied and removed. This method make use of the fact that hydrogen is hard to liquefy. 2) The PSA method: high-purity hydrogen is recovered by the adsorption of other constituents at high pressures. This technique makes use of the fact that the adsorption capacity of an adsorbent varies with the partial pressure of the substances being adsorbed. 3) Membrane separation: a permeation separation method that uses a functional polymer separation membrane, and that depends on the fact that hydrogen has a low molecular weight in comparison with the other constituents. (19 refs.) (In Japanese)

Low-complexity linewidth-tolerant time domain sub-symbol optical phase noise suppression in CO-OFDM systems.

Science.gov (United States)

Hong, Xuezhi; Hong, Xiaojian; Zhang, Junwei; He, Sailing

2016-03-07

Two linewidth-tolerant optical phase noise suppression algorithms, non-decision aided sub-symbol optical phase noise suppression (NDA-SPS) and partial-decision aided sub-symbol optical phase noise suppression (PDA-SPS), based on low-complexity time domain sub-symbol processing are proposed for coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. High accuracy carrier phase estimation is achieved in the NDA-SPS algorithm without decision error propagation. Compared with NDA-SPS, partial-decision aided estimation is introduced in PDA-SPS to reduce the pilot-overhead by half, yet only a small performance degradation is induced. The principles and computational complexities of the proposed algorithms are theoretically analyzed. By adopting specially designed comb-type pilot subcarriers, multiplier-free observation-based matrix generation is realized in the proposed algorithms. Computationally intensive discrete Fourier transform (DFT) or inverse DFT (IDFT) operations, which are usually carried out in other high-performance inter-carrier-interference (ICI) mitigation algorithms multiple times, are completely avoided. Compared with several other sub-symbol algorithms, the proposed algorithms with lower complexities offer considerably larger laser linewidth tolerances as demonstrated by Monte-Carlo simulations. Numerical analysis verifies that the optimal performance of PDA-SPS can be achieved with moderate numbers of sub-symbols.

Improvement in fuel utilization in pressurized heavy water reactors due to increased heavy water purity

International Nuclear Information System (INIS)

Balakrishnan, M.R.

1991-01-01

This paper reports that in a pressurized heavy water reactor (PHWR), the reactivity of the reactor and, consequently, the discharge burnup of the fuel depend on the isotopic purity of the heavy water used in the reactor. The optimal purity of heavy water used in PHWRs, in turn, depends on the cost of fabricated uranium fuel and on the incremental cost incurred in improving the heavy water purity. The physics and economics aspects of the desirability of increasing the heavy water purity in PHWRs in India were first examined in 1978. With the cost data available at that time, it was found that improving the heavy water purity from 99.80% to 99.95% was economically attractive. The same problem is reinvestigated with current cost data. Even now, there is sufficient incentive to improve the isotopic purity of heavy water used in PHWRs. Admittedly, the economic advantage that can be derived depends on the cost of the fabricated fuel. Nevertheless, irrespective of the economics, there is also a fairly substantial saving in natural uranium. That the increase in the heavy water purity is to be maintained only in the low-pressure moderator system, and not in the high-pressure coolant system, makes the option of achieving higher fuel burnup with higher heavy water purity feasible

Linewidth of Josephson oscillations in YBa2Cu3O7-x grain-boundary junctions

DEFF Research Database (Denmark)

Divin, Yu. Ya.; Mygind, Jesper; Pedersen, Niels Falsig

1993-01-01

The AC Josephson effect in YBa2Cu3O7-x grain-boundary junctions (GBJs) was studied in the temperature range from 4 K to 90 K. The temperature dependence of the linewidth of millimeter-wave Josephson oscillations was measured, and it is shown that the derived effective noise temperature of GBJ mig...... Josephson oscillations observed at 77 K was equal to 380 MHz, which demonstrates the applicability of GBJ, particularly in the field of radiation spectroscopy, even at liquid nitrogen temperatures...

Coherence and linewidth studies of a 4-nm high power FEL

International Nuclear Information System (INIS)

Fawley, W.M.; Sessler, A.M.; Scharlemann, E.T.

1993-05-01

Recently the SSRL/SLAC and its collaborators elsewhere have considered the merits of a 2 to 4-nm high power FEL utilizing the SLAC linac electron beam. The FEL would be a single pass amplifier excited by spontaneous emission rather than an oscillator, in order to eliminate the need for a soft X-ray resonant cavity. We have used GINGER, a multifrequency 2D FEL simulation code, to study the expected linewidth and coherence properties of the FEL, in both the exponential and saturated gain regimes. We present results concerning the effective shot noise input power and mode shape, the expected subpercent output line widths, photon flux, and the field temporal and spatial correlation functions. We also discuss the effects of tapering the wiggler upon the output power and line width

Statistical distribution of the local purity in a large quantum system

International Nuclear Information System (INIS)

De Pasquale, A; Pascazio, S; Facchi, P; Giovannetti, V; Parisi, G; Scardicchio, A

2012-01-01

The local purity of large many-body quantum systems can be studied by following a statistical mechanical approach based on a random matrix model. Restricting the analysis to the case of global pure states, this method proved to be successful, and a full characterization of the statistical properties of the local purity was obtained by computing the partition function of the problem. Here we generalize these techniques to the case of global mixed states. In this context, by uniformly sampling the phase space of states with assigned global mixedness, we determine the exact expression of the first two moments of the local purity and a general expression for the moments of higher order. This generalizes previous results obtained for globally pure configurations. Furthermore, through the introduction of a partition function for a suitable canonical ensemble, we compute the approximate expression of the first moment of the marginal purity in the high-temperature regime. In the process, we establish a formal connection with the theory of quantum twirling maps that provides an alternative, possibly fruitful, way of performing the calculation. (paper)

Confined recrystallization of high-purity aluminium during accumulative roll bonding of aluminium laminates

International Nuclear Information System (INIS)

Chekhonin, Paul; Beausir, Benoît; Scharnweber, Juliane; Oertel, Carl-Georg; Hausöl, Tina; Höppel, Heinz Werner; Brokmeier, Heinz-Günter; Skrotzki, Werner

2012-01-01

Aluminium laminates consisting of high-purity aluminium and commercially pure aluminium have been produced by accumulative roll bonding (ARB) at ambient temperature for up to 10 cycles. To study the microstructure and texture development of the high-purity aluminium layers with regard to the shrinking layer thickness during ARB, microstructure and texture investigations were carried out by electron backscatter diffraction and neutron and X-ray diffraction, respectively. While the commercially pure aluminium layers develop an ultrafine-grained microstructure, partial discontinuous recrystallization occurs in the high-purity layers. The texture of the high-purity layers mainly consists of Cube and “Tilted Cube” (tilted with respect to the transverse direction) components. The experimental results are discussed with respect to confined recrystallization in the ARB aluminium laminates.

The Research about Preparation of High Purity Hexachlorodisilane

Science.gov (United States)

Wan, Ye; Zhao, Xiong; Yan, Dazhou; Zhao, Yu; Guo, Shuhu; Wang, Lei; Yang, Dian

2017-12-01

This article demonstrated a technology for producing high purity hexachlorodisilane what is one raw material of Semiconductor industry, which using the method of combination adsorption with rectification, whose material was from polysilicon residues of polysilicon company. This technology could remove most high boiling points chloro-silicane impurities and metal impurities effectively. The purity of Si2Cl6 produced by this technology can be up to 99.9%, the content of metal impurities can be low at 4ppb, which can meet the requirement of industy using completely. The technology extends the routes of Si2Cl6 in localization, having the advantages of simple process, continuous operation, and large capacity and so on.

A High-Purity Alumina for Use in Studies of Shock Loaded Samples

Science.gov (United States)

Lacina, David; Neel, Christopher

2017-06-01

We report the results of plate impact experiments on a potential new ``standard'' material, Coorstek Plasmapure-UC (99.9% purity) polycrystalline alumina, for use in non-conduction, impact environment, shock loading studies. This work was motivated by a desire to find a 99.9% purity alumina to replace the now unavailable Coors Vistal (99.9%) alumina, as it was hoped the Hugoniot elastic limit (HEL) of the new standard would match the 9-11 GPa value of Vistal. Shock response data, including the HEL, Hugoniot particle velocities, Hugoniot shock velocities, stress vs volume, and release wave speeds, was obtained up to 14 GPa. This data will be compared with Hugoniot curve data for other high purity alumina to contrast differences in the shock response, and is intended to be useful in impedance matching calculations. We will show that the HEL of Plasmapure-UC alumina is 5.5 GPa and speculate on causes for this lower than expected value. We will also explore why the elastic-plastic response for Plasmapure-UC alumina differs from what has been observed from other high purity alumina. The final result of this work is to recommend a well-characterized, lower purity alumina (Coorstek AD-995) as a potential new ``standard'' material.

High-temperature mechanical properties of high-purity 70 mass% Cr-Fe alloy

Energy Technology Data Exchange (ETDEWEB)

Asahina, M.; Harima, N.; Takaki, S.; Abiko, K. [Tohoku Univ., Sendai (Japan). Inst. for Materials Research

2002-01-16

An ingot of high-purity 70 mass% Cr-Fe alloy was prepared by high-frequency induction melting in a high-purity argon atmosphere using a cold copper crucible. Its tensile properties such as hot-ductility and tensile strength were measured, and compared with the results for a high-purity 50 mass% Cr-Fe alloy, a high-purity 60 mass% Cr-Fe alloy and a Ni-based super-alloy. The formation of {sigma}-phase was also examined. The purity of a 70Cr-Fe alloy (70 mass% Cr-Fe alloy) ingot is more than 99.98 mass% and the total amount of gaseous impurities (C, N, O, S, H) in the 70Cr-Fe alloy is 69.9 mass ppm. The strength of the 70Cr-Fe alloy is higher than those of the 60Cr-Fe alloy and the 50Cr-Fe alloy at the temperatures between 293 and 1573 K, without decrease in ductility with increasing Cr content. The 70Cr-Fe alloy also possesses excellent high-temperature ductility. The {sigma}-phase was not observed after aging of 3.6 Ms at 873 K. Consequently, the 70Cr-Fe alloy is an excellent alloy as the base of super heat-resistant alloys. (orig.)

Growth and characterization of high-purity SiC single crystals

Science.gov (United States)

Augustine, G.; Balakrishna, V.; Brandt, C. D.

2000-04-01

High-purity SiC single crystals with diameter up to 50 mm have been grown by the physical vapor transport method. Finite element analysis was used for thermal modeling of the crystal growth cavity in order to reduce stress in the grown crystal. Crystals are grown in high-purity growth ambient using purified graphite furniture and high-purity SiC sublimation sources. Undoped crystals up to 50 mm in diameter with micropipe density less than 100 cm -2 have been grown using this method. These undoped crystals exhibit resistivities in the 10 3 Ω cm range and are p-type due to the presence of residual acceptor impurities, mainly boron. Semi-insulating SiC material is obtained by doping the crystal with vanadium. Vanadium has a deep donor level located near the middle of the band gap, which compensates the residual acceptor resulting in semi-insulating behavior.

Method of determination of radiochemical purity of gallium-67 citrate injection

International Nuclear Information System (INIS)

Wang Quanji

1985-01-01

A simple method is used to compare the effect of five developing agents on the radiochemical purity of neutral products of 67 GaCit and on Rsub(f) values. Two preferable developing agents are recommended as suitable for the identification of 67 GaCit injection in its production. The effect of six pH values of different developing agents on radiochemical purity, Rsub(f) and chromatogram are compared for the neutral products. The results of the experiments show that the ascending paper chromatography with 1:2:4 pyridine/ethanol/water and 85:15 methanol/water is preferable for the determination of the radiochemical purity of 67 GaCit. The other developing agents also can be used if there are not any impurities except gallium radioisotopes

Tuning for optimal performance in angle control, uniformity, and energy purity

International Nuclear Information System (INIS)

Liebert, Reuel B.; Olson, Joseph C.; Arevalo, Edwin A.; Downey, Daniel F.

2005-01-01

Advances in reducing the sizes of device structures and line widths place increasing demands on the accuracy of dopant placement and the control of dopant motion during activation anneals. Serial process high current ion implantation systems seek to produce beams in which the angles are controlled to high precision avoiding the angles introduced by conical structures used for holding wafers on spinning discs in batch systems. However, ion optical corrections and control of incident beam angle, dose uniformity, high throughput and energy purity often present apparently contradictory requirements in machine design. Data is presented to illustrate that tuning procedures can be used to simultaneously optimize angle purity in both x and y planes as well as control energy purity and dose uniformity

Production of high purity radiothallium

International Nuclear Information System (INIS)

Lebowitz, E.; Greene, M.W.

1976-01-01

The method of producing high-purity thallium-201 for use as a myocardial scanning agent comprises the steps of irradiating a thallium target with protons to give the reaction 203 Tl(p,3n) 201 Pb, separating in ion exchange columns the lead from the thallium isotopes, permitting the lead to decay, and then purifying the thallium solution and converting the thallium present to thallous form in which it can be used

[Research on determination of chemical purity of andrographolide by coulometric titration method].

Science.gov (United States)

Yang, Ning; Yang, Dezhi; Xu, Lishen; Lv, Yang

2010-04-01

The determination of chemical purity of andrographolide by coulometric titration method is studied in this paper. The coulometric titration was carried out in a mixture composed of 4 mol x L(-1) hydrochloric acid and 1 mol x L(-1) potassium bromide solution and 1 mol x L(-1) potassium nitrate solution (1:1). Bromine is electrogenerated at the anode and reacts with the andrographolide. The number of electrons involved in the eleatrode reaction is 2. Purity of andrographolide is 99.76% compared with 99.77% utilizing area normalization method by HPLC. The RSD are 0.33% and 0.02% respectively. The results from two methods are consistent, so the determination of chemical purity of andrographolide by coulometric titration method is scientific and feasible. The method is rapid, simple, convenient, sensitive and accurate. The reference material is not essential in the method. The method is suitable for determination of chemical purity of andrographolide.

Development of high purity niobium material for superconducting cavities

International Nuclear Information System (INIS)

Umezawa, Hiroaki; Takeuchi, Koichi; Sakita, Kohei; Suzuki, Takafusa; Saito, Kenji; Noguchi, Shuichi.

1993-01-01

For the superconducting niobium cavities, issues of thermal quench and field emission have to be solved to achieve a high field gradient (>25MV/m) for TESLA (TeV Energy Superconducting Linear Accelerator). In order to overcome the quench, upgrading of thermal conductivity of niobium material at the low temperature is very important. On the reduction of the field emission not only dust particles but also defect, impurity and inhomogeneity should be considered. Therefore development of high purity niobium material is very important to solve these issues. This paper describes the our latest R and D for high purity niobium material. (author)

Development of atomic spectroscopy technologies - Hyperfine structure of 2 period atoms using optogalvanic effects

Energy Technology Data Exchange (ETDEWEB)

Kwon, Nam Ic [Hankuk University of foreign studies, Seoul (Korea)

2000-03-01

The source of anomalous broad linewidth of 3{sup 3}P{sub 1},{sub 2},{sub 3}-3{sup 3}D{sub 2},{sub 3},4(3s') transition was explained. The broad optogalvanic spectrum was consisted of two gaussian peaks of different linewidths, and they are separated by 250 MHz. The Narrow peak, which has linewidth of room temperature, is from oxygen atoms already separated, and the shifted broad peak, which has linewidth corresponding to a temperature of 9000 K, is from weakly bound molecular ions. Obtained hyperfine spectrum of fluorine atom at the expected frequency, was too weak to analyze hyperfine structure constants. Microwave discharge might be necessary for higher density of excited state. 16 refs., 11 figs. (Author)

Theoretical analyses of an injection-locked diode-pumped rubidium vapor laser.

Science.gov (United States)

Cai, He; Gao, Chunqing; Liu, Xiaoxu; Wang, Shunyan; Yu, Hang; Rong, Kepeng; An, Guofei; Han, Juhong; Zhang, Wei; Wang, Hongyuan; Wang, You

2018-04-02

Diode-pumped alkali lasers (DPALs) have drawn much attention since they were proposed in 2001. The narrow-linewidth DPAL can be potentially applied in the fields of coherent communication, laser radar, and atomic spectroscopy. In this study, we propose a novel protocol to narrow the width of one kind of DPAL, diode-pumped rubidium vapor laser (DPRVL), by use of an injection locking technique. A kinetic model is first set up for an injection-locked DPRVL with the end-pumped configuration. The laser tunable duration is also analyzed for a continuous wave (CW) injection-locked DPRVL system. Then, the influences of the pump power, power of a master laser, and reflectance of an output coupler on the output performance are theoretically analyzed. The study should be useful for design of a narrow-linewidth DPAL with the relatively high output.

Investigation of single lateral mode for 852nm diode lasers with ridge waveguide design

Science.gov (United States)

Liu, Chu; Guan, Baolu; Mi, Guoxin; Liao, Yiru; Liu, Zhenyang; Li, Jianjun; Xu, Chen

2016-11-01

852nm Narrow linewidth lasers can be widely used in the field of ultra-fine spectrum measurement, Cs atomic clock control, satellite and optical fiber communication and so on. Furthermore, the stability of the single lateral mode is a very important condition to guarantee the narrow linewidth lasers. Here we investigate experimentally the influence of the narrow ridge structure and asymmetrical waveguide design on the stability single lateral mode of an 852nm diode laser. According to the waveguide theoretical analysis, ridge mesa etch depth (Δη , related to the refractive index difference of parallel to the junction) and ridge mesa width (the narrower the more control force to low order mode) are the main elements for lateral modes. In this paper, we designed different structures to investigate and verify major factors for lateral mode by experiment, and to confirm our thought. Finally, the 5μm mesa ridge laser, 800nm etch depth, with groove structure obtains excellent steady single lateral mode output by 150mA operating current and 30°C temperature. The optical spectrum FWHM is 0.5nm and side mode suppression ratio is 27dBm with uncoated. The laser with 1mm cavity length showed the threshold current of 50mA, a lasing wavelength of λ = 852.6nm, slope efficiency of above 0.7mW/mA. We accomplished single lateral mode of ridge waveguide edge-emitting lasers which can also be used as a laser source in the ultra-narrow linewidth external cavity laser system.

Purity-activity relationships of natural products: the case of anti-TB active ursolic acid.

Science.gov (United States)

Jaki, Birgit U; Franzblau, Scott G; Chadwick, Lucas R; Lankin, David C; Zhang, Fangqiu; Wang, Yuehong; Pauli, Guido F

2008-10-01

The present study explores the variability of biological responses from the perspective of sample purity and introduces the concept of purity-activity relationships (PARs) in natural product research. The abundant plant triterpene ursolic acid (1) was selected as an exemplary natural product due to the overwhelming number yet inconsistent nature of its approximate 120 reported biological activities, which include anti-TB potential. Nine different samples of ursolic acid with purity certifications were obtained, and their purity was independently assessed by means of quantitative 1H NMR (qHNMR). Biological evaluation consisted of determining MICs against two strains of virulent Mycobacterium tuberculosis and IC50 values in Vero cells. Ab initio structure elucidation provided unequivocal structural confirmation and included an extensive 1H NMR spin system analysis, determination of nearly all J couplings and the complete NOE pattern, and led to the revision of earlier reports. As a net result, a sigmoid PAR profile of 1 was obtained, demonstrating the inverse correlation of purity and anti-TB bioactivity. The results imply that synergistic effects of 1 and its varying impurities are the likely cause of previously reported antimycobacterial potential. Generating PARs is a powerful extension of the routinely performed quantitative correlation of structure and activity ([Q]SAR). Advanced by the use of primary analytical methods such as qHNMR, PARs enable the elucidation of cases like 1 when increasing purity voids biological activity. This underlines the potential of PARs as a tool in drug discovery and synergy research and accentuates the need to routinely combine biological testing with purity assessment.

Improving the accuracy of a dual-comb interferometer by suppressing the relative linewidth

Science.gov (United States)

Zhu, Zebin; Xu, Guangyao; Ni, Kai; Zhou, Qian; Wu, Guanhao

2018-04-01

We present a compact system of synchronization for two fiber-based optical frequency comb lasers. We use a free-running continuous wave laser as an intermediary to obtain the relative noise of two combs and employ an intra-cavity electro-optic modulator (EOM) to achieve active phase feedback for fast synchronization. The EOM bandwidth is 150 kHz and the relative linewidth is suppressed markedly from 300 kHz to sub-hertz values. The relative effective timing jitter of the two pulse trains is also decreased from 680 fs to 25 fs. The proposed method shows promise for developing a high-performance, low-cost, fiber-based dual-comb interferometer for ranging or spectroscopy.

Characterisation of two AGATA asymmetric high purity germanium capsules

International Nuclear Information System (INIS)

Colosimo, S.J.; Moon, S.; Boston, A.J.; Boston, H.C.; Cresswell, J.R.; Harkness-Brennan, L.; Judson, D.S.; Lazarus, I.H.; Nolan, P.J.; Simpson, J.; Unsworth, C.

2015-01-01

The AGATA spectrometer is an array of highly segmented high purity germanium detectors. The spectrometer uses pulse shape analysis in order to track Compton scattered γ-rays to increase the efficiency of nuclear spectroscopy studies. The characterisation of two high purity germanium detector capsules for AGATA of the same A-type has been performed at the University of Liverpool. This work will examine the uniformity of performance of the two capsules, including a comparison of the resolution and efficiency as well as a study of charge collection. The performance of the capsules shows good agreement, which is essential for the efficient operation of the γ-ray tracking array

Characterisation of two AGATA asymmetric high purity germanium capsules

Energy Technology Data Exchange (ETDEWEB)

Colosimo, S.J., E-mail: sjc@ns.ph.liv.ac.uk [Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Moon, S.; Boston, A.J.; Boston, H.C.; Cresswell, J.R.; Harkness-Brennan, L.; Judson, D.S. [Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Lazarus, I.H. [STFC Daresbury, Daresbury, Warrington WA4 4AD (United Kingdom); Nolan, P.J. [Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Simpson, J. [STFC Daresbury, Daresbury, Warrington WA4 4AD (United Kingdom); Unsworth, C. [Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom)

2015-02-11

The AGATA spectrometer is an array of highly segmented high purity germanium detectors. The spectrometer uses pulse shape analysis in order to track Compton scattered γ-rays to increase the efficiency of nuclear spectroscopy studies. The characterisation of two high purity germanium detector capsules for AGATA of the same A-type has been performed at the University of Liverpool. This work will examine the uniformity of performance of the two capsules, including a comparison of the resolution and efficiency as well as a study of charge collection. The performance of the capsules shows good agreement, which is essential for the efficient operation of the γ-ray tracking array.

Narrow, duplicated internal auditory canal

Energy Technology Data Exchange (ETDEWEB)

Ferreira, T. [Servico de Neurorradiologia, Hospital Garcia de Orta, Avenida Torrado da Silva, 2801-951, Almada (Portugal); Shayestehfar, B. [Department of Radiology, UCLA Oliveview School of Medicine, Los Angeles, California (United States); Lufkin, R. [Department of Radiology, UCLA School of Medicine, Los Angeles, California (United States)

2003-05-01

A narrow internal auditory canal (IAC) constitutes a relative contraindication to cochlear implantation because it is associated with aplasia or hypoplasia of the vestibulocochlear nerve or its cochlear branch. We report an unusual case of a narrow, duplicated IAC, divided by a bony septum into a superior relatively large portion and an inferior stenotic portion, in which we could identify only the facial nerve. This case adds support to the association between a narrow IAC and aplasia or hypoplasia of the vestibulocochlear nerve. The normal facial nerve argues against the hypothesis that the narrow IAC is the result of a primary bony defect which inhibits the growth of the vestibulocochlear nerve. (orig.)

Flooding correlations in narrow channel

International Nuclear Information System (INIS)

Kim, S. H.; Baek, W. P.; Chang, S. H.

1999-01-01

Heat transfer in narrow gap is considered as important phenomena in severe accidents in nuclear power plants. Also in heat removal of electric chip. Critical heat flux(CHF) in narrow gap limits the maximum heat transfer rate in narrow channel. In case of closed bottom channel, flooding limited CHF occurrence is observed. Flooding correlations will be helpful to predict the CHF in closed bottom channel. In present study, flooding data for narrow channel geometry were collected and the work to recognize the effect of the span, w and gap size, s were performed. And new flooding correlations were suggested for high-aspect-ratio geometry. Also, flooding correlation was applied to flooding limited CHF data

Spectral Purity Enhancement via Polyphase Multipath Circuits

NARCIS (Netherlands)

Mensink, E.; Klumperink, Eric A.M.; Nauta, Bram

2004-01-01

The central question of this paper is: can we enhance the spectral purity of nonlinear circuits by using polyphase multipath circuits? The basic idea behind polyphase multipath circuits is to split the nonlinear circuits into two or more paths and exploit phase differences between these paths to

Fused salt processing of impure plutonium dioxide to high-purity plutonium metal

International Nuclear Information System (INIS)

Mullins, L.J.; Christensen, D.C.; Babcock, B.R.

1982-01-01

A process for converting impure plutonium dioxide (approx. 96% pure) to high-purity plutonium metal (>99.9%) was developed. The process consists of reducing the oxide to an impure plutonium metal intermediate with calcium metal in molten calcium chloride. The impure intermediate metal is cast into an anode and electrorefined to produce high-purity plutonium metal. The oxide reduction step is being done now on a 0.6-kg scale with the resulting yield being >99.5%. The electrorefining is being done on a 4.0-kg scale with the resulting yield being 80 to 85%. The purity of the product, which averages 99.98%, is essentially insensitive to the purity of the feed metal. The yield, however, is directly dependent on the chemical composition of the feed. To date, approximately 250 kg of impure oxide has been converted to pure metal by this processing sequence. The availability of impure plutonium dioxide, together with the need for pure plutonium metal, makes this sequence a valuable plutonium processing tool

Effect of Aluminum Purity on the Pore Formation of Porous Anodic Alumina

International Nuclear Information System (INIS)

Kim, Byeol; Lee, Jin Seok

2014-01-01

Anodic alumina oxide (AAO), a self-ordered hexagonal array, has various applications in nanofabrication such as the fabrication of nanotemplates and other nanostructures. In order to obtain highly ordered porous alumina membranes, a two-step anodization or prepatterning of aluminum are mainly conducted with straight electric field. Electric field is the main driving force for pore growth during anodization. However, impurities in aluminum can disturb the direction of the electric field. To confirm this, we anodized two different aluminum foil samples with high purity (99.999%) and relatively low purity (99.8%), and compared the differences in the surface morphologies of the respective aluminum oxide membranes produced in different electric fields. Branched pores observed in porous alumina surface which was anodized in low-purity aluminum and the size; dimensions of the pores were found to be usually smaller than those obtained from high-purity aluminum. Moreover, anodization at high voltage proceeds to a significant level of conversion because of the high speed of the directional electric field. Consequently, anodic alumina membrane of a specific morphology, i. e., meshed pore, was produced

Effect of Aluminum Purity on the Pore Formation of Porous Anodic Alumina

Energy Technology Data Exchange (ETDEWEB)

Kim, Byeol; Lee, Jin Seok [Sookmyung Women' s Univ., Seoul (Korea, Republic of)

2014-02-15

Anodic alumina oxide (AAO), a self-ordered hexagonal array, has various applications in nanofabrication such as the fabrication of nanotemplates and other nanostructures. In order to obtain highly ordered porous alumina membranes, a two-step anodization or prepatterning of aluminum are mainly conducted with straight electric field. Electric field is the main driving force for pore growth during anodization. However, impurities in aluminum can disturb the direction of the electric field. To confirm this, we anodized two different aluminum foil samples with high purity (99.999%) and relatively low purity (99.8%), and compared the differences in the surface morphologies of the respective aluminum oxide membranes produced in different electric fields. Branched pores observed in porous alumina surface which was anodized in low-purity aluminum and the size; dimensions of the pores were found to be usually smaller than those obtained from high-purity aluminum. Moreover, anodization at high voltage proceeds to a significant level of conversion because of the high speed of the directional electric field. Consequently, anodic alumina membrane of a specific morphology, i. e., meshed pore, was produced.

Surface passivation of high purity granular metals: zinc, cadmium, lead

Directory of Open Access Journals (Sweden)

Pirozhenko L. A.

2017-10-01

Full Text Available For the high purity metals (99.9999%, such as zinc, cadmium, and lead, which are widely used as initial components in growing semiconductor and scintillation crystals (CdTe, CdZnTe, ZnSe, (Cd, Zn, Pb WO4, (Cd, Zn, Pb MoO4 et al., it is very important to ensure reliable protection of the surface from oxidation and adsorption of impurities from the atmosphere. The specific features of surface passivation of high purity cadmium, lead and zinc are not sufficiently studied and require specific methodologies for further studies. The use of organic solutions in the schemes of chemical passivation of the investigated metals avoids hydrolysis of the obtained protective films. The use of organic solvents with pure cation and anion composition as the washing liquid prevents chemisorption of ions present in the conventionally used distilled water. This keeps the original purity of the granular metals. Novel compositions of etchants and etching scheme providing simultaneous polishing and passivation of high purity granular Zn, Cd and Pb are developed. Chemical passivation allows storing metals in the normal atmospheric conditions for more than half a year for Zn and Cd and up to 30 days for Pb without changing the state of the surface. The use of the glycerol-DMF solution in the processes for obtaining Pb granules provides self-passivation of metal surfaces and eliminates the additional chemical processing while maintaining the quality of corrosion protection.

Definition of the generalized criterion of estimation of ecological purity of textile products

International Nuclear Information System (INIS)

Gintibidze, N.; Valishvili, T.

2009-01-01

One of actual problems is the estimation of hygienic and ecological properties of fabrics on the basis of the data on the properties of initial fiber. In the present article, the definition of generalized criterion of the estimation of ecological purity of textile products is discussed. The estimation is based on the International Standard EKO-TEX-100, regulating the contents of inorganic and organic compounds in textile production. The determination of all listed substances is made according to appropriate techniques for each parameter. The quantity of substances is determined and compared with norms. The judgement about ecological purity is made by separate parameters. There is no uniform parameter which could estimate the degree of ecological purity of textile products. For calculating the generalized criterion of estimation of ecological purity of textile products, it is offered to estimate each criterion by the points corresponding to each factor. The textile product is recognized as ecologically pure (environment friendly) if the total estimate is more than 1. (author)

Synthesis of high purity monoglycerides from crude glycerol and palm stearin

Directory of Open Access Journals (Sweden)

Pakamas Chetpattananondh

2008-07-01

Full Text Available The optimum conditions for the glycerolysis of palm stearin and crude glycerol derived from biodiesel process werefound to be a reaction temperature of 200oC with a molar ratio of crude glycerol to palm stearin of 2.5:1, and a reaction timeof 20 minutes. The yield and purity of monoglycerides obtained under these conditions was satisfactory as compared withthe glycerolysis of pure glycerol. To increase the purity of monoglycerides a two-step process, removal of residual glyceroland crystallization, was proposed instead of either vacuum or molecular distillation. Residual glycerol was removed byadding hydrochloric acid followed by washing with hot water. Optimum conditions for crystallization were achieved byusing isooctane as a solvent and a turbine impeller speed of 200 rpm at a crystallization temperature of 35oC. A purity notexceeding 99 percent of monoglycerides was obtained with monopalmitin as the major product.

[Purity Detection Model Update of Maize Seeds Based on Active Learning].

Science.gov (United States)

Tang, Jin-ya; Huang, Min; Zhu, Qi-bing

2015-08-01

Seed purity reflects the degree of seed varieties in typical consistent characteristics, so it is great important to improve the reliability and accuracy of seed purity detection to guarantee the quality of seeds. Hyperspectral imaging can reflect the internal and external characteristics of seeds at the same time, which has been widely used in nondestructive detection of agricultural products. The essence of nondestructive detection of agricultural products using hyperspectral imaging technique is to establish the mathematical model between the spectral information and the quality of agricultural products. Since the spectral information is easily affected by the sample growth environment, the stability and generalization of model would weaken when the test samples harvested from different origin and year. Active learning algorithm was investigated to add representative samples to expand the sample space for the original model, so as to implement the rapid update of the model's ability. Random selection (RS) and Kennard-Stone algorithm (KS) were performed to compare the model update effect with active learning algorithm. The experimental results indicated that in the division of different proportion of sample set (1:1, 3:1, 4:1), the updated purity detection model for maize seeds from 2010 year which was added 40 samples selected by active learning algorithm from 2011 year increased the prediction accuracy for 2011 new samples from 47%, 33.75%, 49% to 98.89%, 98.33%, 98.33%. For the updated purity detection model of 2011 year, its prediction accuracy for 2010 new samples increased by 50.83%, 54.58%, 53.75% to 94.57%, 94.02%, 94.57% after adding 56 new samples from 2010 year. Meanwhile the effect of model updated by active learning algorithm was better than that of RS and KS. Therefore, the update for purity detection model of maize seeds is feasible by active learning algorithm.

A High Reliability Frequency Stabilized Semiconductor Laser Source, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Ultrastable, narrow linewidth, high reliability MOPA sources are needed for high performance LIDARs in NASA for, wind speed measurement, surface topography and earth...

Radiation protection clothing in X-ray diagnostics. Comparison of attenuation equivalents in narrow beam and inverse broad-beam geometry

International Nuclear Information System (INIS)

Pichler, Thomas; Schoepf, T.; Ennemoser, O.

2011-01-01

Purpose: Standard DIN EN 61 331-1 for attenuation measurements in the narrow and broad beam as well as DIN 6857-1 for the determination of shielding properties in the inverse broad-beam geometry are available for testing the attenuation of protection clothing. The attenuation measurements in the narrow beam don't consider scattered radiation and fluorescence due to the arrangement. This leads to the fact that the protective effect of lead-free materials will be misestimated when compared to lead. Therefore, the differences in attenuation equivalents, determined by both test methods for topical radiation protection aprons, were examined. Materials and Methods: The attenuations in inverse broad-beam geometry according to DIN 6857-1 and in the narrow beam according to DIN EN 61 331-1 were measured using commercially available aprons. They were made of lead, lead-reduced and lead-free materials. For determination of the attenuation equivalents, certificated lead-foils with high purity and a precise thickness of 0.1 to 1.25 mm were used. Results: The measurements in the narrow beam according to DIN EN 61 331-1 showed that nearly all aprons reach the required lead equivalent at mid-range tube voltages of 100 kV. At higher and lower tube voltages, the requirements of DIN EN 61 331-3 were largely not met. In contrast, the testing of the same aprons in inverse broad-beam geometry according to DIN 6857-1 showed that only a few aprons meet the requirements for being classified in the nominal protection class. Conclusion: The measurements suggest that testing method DIN 6857-1 has yet to prevail and that manufacturers are just beginning to develop the appropriate protective materials. (orig.)

104 evaluation of microbiological purity of some brands of ...

African Journals Online (AJOL)

DR. AMINU

Keywords: Microbiological purity, tetracycline, contaminants, bacterial load, fungal load, microbiological ... Just like food substances, pharmaceutical products .... Malaysia. Chlortetracycline a. Mar. 2005. Mar. 2008. Ghana b. Aug. 2005. Aug.

Ion-exchange preparation of high-purity vanadium acid from industrial liquors

International Nuclear Information System (INIS)

Sajdakhmedov, U.A.; Arslanov, Sh.S.; Vulikh, A.I.

1994-01-01

The results of investigations on production of special-purity vanadium acid and vanadium oxide directly from process solutions (technical grade liquors) using ionites are presented. Potentiality of thorough purification of vanadium(5) oxide, when producing vanadium acid on the KU-2 cationite with subsequent purification on anionite, is shown. On the basis of the results obtained a principle flowsheet of ion-exchange production of high-purity vanadium(5) oxide from industrial liquors has been developed. 2 refs.; 1 fig.; 4 tabs

Spectroscopic Determination of Trace Contaminants in High-Purity Oxygen

Science.gov (United States)

Hornung, Steven

2013-01-01

Oxygen used for extravehicular activities (EVAs) must be free of contaminants because a difference in a few tenths of a percent of argon or nitrogen content can mean significant reduction in available EVA time. These inert gases build up in the extravehicular mobility unit because they are not metabolized or scrubbed from the atmosphere. A prototype optical emission technique capable of detecting argon and nitrogen below 0.1% in oxygen has been developed. This instrument uses a glow discharge in reduced-pressure gas to produce atomic emission from the species present. Because the atomic emission lines from oxygen, nitrogen, and argon are discrete, and in many cases well-separated, trace amounts of argon and nitrogen can be detected in the ultraviolet and visible spectrum. This is a straightforward, direct measurement of the target contaminants, and may lend itself to a device capable of on-orbit verification of oxygen purity. A glow discharge is a plasma formed in a low-pressure (1 to 10 Torr) gas cell between two electrodes. Depending on the configuration, voltages ranging from 200 V and above are required to sustain the discharge. In the discharge region, the gas is ionized and a certain population is in the excited state. Light is produced by the transitions from the excited states formed in the plasma to the ground state. The spectrum consists of discrete, narrow emission lines for the atomic species, and broader peaks that may appear as a manifold for molecular species such as O2 and N2, the wavelengths and intensities of which are a characteristic of each atom. The oxygen emission is dominated by two peaks at 777 and 844 nm.

Active Faraday optical frequency standard.

Science.gov (United States)

Zhuang, Wei; Chen, Jingbiao

2014-11-01

We propose the mechanism of an active Faraday optical clock, and experimentally demonstrate an active Faraday optical frequency standard based on narrow bandwidth Faraday atomic filter by the method of velocity-selective optical pumping of cesium vapor. The center frequency of the active Faraday optical frequency standard is determined by the cesium 6 (2)S(1/2) F=4 to 6 (2)P(3/2) F'=4 and 5 crossover transition line. The optical heterodyne beat between two similar independent setups shows that the frequency linewidth reaches 281(23) Hz, which is 1.9×10(4) times smaller than the natural linewidth of the cesium 852-nm transition line. The maximum emitted light power reaches 75 μW. The active Faraday optical frequency standard reported here has advantages of narrow linewidth and reduced cavity pulling, which can readily be extended to other atomic transition lines of alkali and alkaline-earth metal atoms trapped in optical lattices at magic wavelengths, making it useful for new generation of optical atomic clocks.

High power all solid state VUV lasers

International Nuclear Information System (INIS)

Zhang, Shen-jin; Cui, Da-fu; Zhang, Feng-feng; Xu, Zhi; Wang, Zhi-min; Yang, Feng; Zong, Nan; Tu, Wei; Chen, Ying; Xu, Hong-yan; Xu, Feng-liang; Peng, Qin-jun; Wang, Xiao-yang; Chen, Chuang-tian; Xu, Zu-yan

2014-01-01

Highlights: • Polarization and pulse repetition rate adjustable ps 177.3 nm laser was developed. • Wavelength tunable ns, ps and fs VUV lasers were developed. • High power ns 177.3 nm laser with narrow linewidth was investigated. - Abstract: We report the investigation on the high power all solid state vacuum ultra-violet (VUV) lasers by means of nonlinear frequency conversion with KBe 2 BO 3 F 2 (KBBF) nonlinear crystal. Several all solid state VUV lasers have developed in our group, including polarization and pulse repetition rate adjustable picosecond 177.3 nm VUV laser, wavelength tunable nanosecond, picosecond and femtosecond VUV lasers, high power ns 177.3 nm laser with narrow linewidth. The VUV lasers have impact, accurate and precise advantage

Injection-seeded tunable mid-infrared pulses generated by difference frequency mixing

Science.gov (United States)

Miyamoto, Yuki; Hara, Hideaki; Masuda, Takahiko; Hiraki, Takahiro; Sasao, Noboru; Uetake, Satoshi

2017-03-01

We report on the generation of nanosecond mid-infrared pulses having frequency tunability, a narrow linewidth, and a high pulse energy. These pulses are obtained by frequency mixing between injection-seeded near-infrared pulses in potassium titanyl arsenate crystals. A continuous-wave external cavity laser diode or a Ti:sapphire ring laser is used as a tunable seeding source for the near-infrared pulses. The typical energy of the generated mid-infrared pulses is in the range of 0.4-1 mJ/pulse. The tuning wavelength ranges from 3142 to 4806 nm. A narrow linewidth of 1.4 GHz and good frequency reproducibility of the mid-infrared pulses are confirmed by observing a rovibrational absorption line of gaseous carbon monoxide at 4587 nm.

High Power Diode Lasers with External Feedback: Overview and Prospects

DEFF Research Database (Denmark)

Chi, Mingjun; Petersen, Paul Michael

2012-01-01

In summary, different external-cavity feedback techniques to improve the spatial beam quality and narrow the linewidth of the output beam from both BALs and TDLs are presented. Broad-area diode laser system with external-cavity feedback around 800 nm can produce several Watts of output power...... with a good beam quality. Tapered diode laser systems with external-cavity feedback around 800 and 1060 nm can deliver more than 2 W output power with diffraction-limited beam quality and can be operated in single-longitudinal mode. These high-brightness, narrow linewidth, and tunable external-cavity diode...... lasers emerge as the next generation of compact lasers that have the potential of replacing conventional high power laser systems in many existing applications....

Pressure-assisted sintering of high purity barium titanate

NARCIS (Netherlands)

van den Cruijsem, S.; Varst, van der P.G.T.; With, de G.; Bortzmeyer, D.; Boussuge, M.; Chartier, Th.; Hausonne, J.M.; Mocellin, A.; Rousset, A.; Thevenot, F.

1997-01-01

The dielectric behaviour of High Purity Barium titanate (HPB) ceramics is strongly dependent on the grain size and porosity. For applications, control of grain size and porosity is required. Pressure-assisted sintering techniques at relatively low temperatures meet these requirements. In this study,

Event timing in high purity germanium coaxial detectors

International Nuclear Information System (INIS)

El-Ibiary, M.Y.

1979-08-01

The timing of gamma ray radiation in systems using high purity coaxial germanium detectors is analyzed and compared to that of systems using Ge(Li) detectors. The analysis takes into account the effect of the residual impurities on the electric field distribution, and hence on the rate of rise of the electrical pulses delivered to the timing module. Conditions under which the electric field distribution could lead to an improvement in timing performance, are identified. The results of the analysis confirm the experimental results published elsewhere and when compared with those for Ge(Li) detectors, which usually operate under conditions of charge carrier velocity saturation, confirm that high purity germanium detectors need not have inferior timing characteristics. A chart is given to provide a quantitative basis on which the trade off between the radius of the detector and its time resolution may be made

Tunable Single Frequency 2.054 Micron Fiber Laser Using New Ho-Doped Fiber, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — In this proposal, we propose to demonstrate and build a near 2 micron widely tunable, narrow linewidth, single frequency fiber laser by developing an innovative...

Optical fiber design with orbital angular momentum light purity higher than 99.9.

Science.gov (United States)

Zhang, Zhishen; Gan, Jiulin; Heng, Xiaobo; Wu, Yuqing; Li, Qingyu; Qian, Qi; Chen, Dongdan; Yang, Zhongmin

2015-11-16

The purity of the synthesized orbital-angular-momentum (OAM) light in the fiber is inversely proportional to channel crosstalk level in the OAM optical fiber communication system. Here the relationship between the fiber structure and the purity is firstly demonstrated in theory. The graded-index optical fiber is proposed and designed for the OAM light propagation with the purity higher than 99.9%. 16 fiber modes (10 OAM modes) have been supported by a specific designed graded-index optical fiber with dispersion less than 35 ps/(km∙nm). Such fiber design has suppressed the intrinsic crosstalk to be lower than -30 dB, and can be potentially used for the long distance OAM optical communication system.

Determination of nanoparticle surface coatings and nanoparticle purity using microscale thermogravimetric analysis.

Science.gov (United States)

Mansfield, Elisabeth; Tyner, Katherine M; Poling, Christopher M; Blacklock, Jenifer L

2014-02-04

The use of nanoparticles in some applications (i.e., nanomedical, nanofiltration, or nanoelectronic) requires small samples with well-known purities and composition. In addition, when nanoparticles are introduced into complex environments (e.g., biological fluids), the particles may become coated with matter, such as proteins or lipid layers. Many of today's analytical techniques are not able to address small-scale samples of nanoparticles to determine purity and the presence of surface coatings. Through the use of an elevated-temperature quartz crystal microbalance (QCM) method we call microscale thermogravimetric analysis, or μ-TGA, the nanoparticle purity, as well as the presence of any surface coatings of nanomaterials, can be measured. Microscale thermogravimetric analysis is used to determine the presence and amount of surface-bound ligand coverage on gold nanoparticles and confirm the presence of a poly(ethylene glycol) coating on SiO2 nanoparticles. Results are compared to traditional analytical techniques to demonstrate reproducibility and validity of μ-TGA for determining the presence of nanoparticle surface coatings. Carbon nanotube samples are also analyzed and compared to conventional TGA. The results demonstrate μ-TGA is a valid method for quantitative determination of the coatings on nanoparticles, and in some cases, can provide purity and compositional data of the nanoparticles themselves.

Evaluation of measurement uncertainty for purity of a monoterpenic acid by small-scale coulometry

Science.gov (United States)

Norte, L. C.; de Carvalho, E. M.; Tappin, M. R. R.; Borges, P. P.

2018-03-01

Purity of the perylic acid (HPe) which is a monoterpenic acid from natural product (NP) with anti-inflammatory and anticancer properties was analyzed by small-scale coulometry (SSC), due to the low availability of HPe on the pharmaceutic market and its high cost. This work aims to present the evaluation of the measurements uncertainty from the purity of HPe by using SSC. Coulometric mean of purity obtained from 5 replicates resulted in 94.23% ± 0.88% (k = 2.06, for an approximately 95% confidence level). These studies aim in the future to develop the production of certified reference materials from NPs.

Spectroscopic Determination of Trace Contaminants in High Purity Oxygen

Science.gov (United States)

Hornung, Steven D.

2011-01-01

Oxygen used for extravehicular activities (EVA) must be free of contaminants because a difference in a few tenths of a percent of argon or nitrogen content can mean significant reduction in available EVA time. These inert gases build up in the extravehicular mobility unit because they are not metabolized or scrubbed from the atmosphere. Measurement of oxygen purity above 99.5% is problematic, and currently only complex instruments such as gas chromatographs or mass spectrometers are used for these determinations. Because liquid oxygen boil-off from the space shuttle will no longer be available to supply oxygen for EVA use, other concepts are being developed to produce and validate high purity oxygen from cabin air aboard the International Space Station. A prototype optical emission technique capable of detecting argon and nitrogen below 0.1% in oxygen was developed at White Sands Test Facility. This instrument uses a glow discharge in reduced pressure gas to produce atomic emission from the species present. Because the atomic emission lines from oxygen, nitrogen, and argon are discrete and in many cases well-separated, trace amounts of argon and nitrogen can be detected in the ultraviolet and visible spectrum. This is a straightforward, direct measurement of the target contaminants and may lend itself to a device capable of on-orbit verification of oxygen purity. System design and optimized measurement parameters are presented.

High purity materials as targets for radioisotope production: Needs ...

Indian Academy of Sciences (India)

Unknown

lity of high purity target materials, natural or enriched, are crucial for any successful radioisotope pro- gramme. Selection ... and blockages detection in buried pipelines are rendered ..... from reputed international suppliers with analysis report.

Deep UV Semiconductor Sources for Advanced Planetary Science Instruments, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — This proposal addresses the need for miniature, narrow-linewidth, deep UV optical sources that operate at very low ambient temperatures for use in advanced in situ...

Tunable Single Frequency 2.05 Micron Fiber Laser Using New Ho-Doped Fiber, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — In this proposal, we propose to demonstrate and build a widely tunable, narrow linewidth, single frequency fiber laser near 2.05 micron by developing an innovative...

Tunable Single Frequency 1.55 Micron Fiber Laser, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — In this proposal, we propose to demonstrate and build a widely tunable, narrow linewidth, single frequency fiber laser by developing an innovative Er/Yb-co-doped...

Controllable growth and optical properties of InP and InP/InAs nanostructures on the sidewalls of GaAs nanowires

International Nuclear Information System (INIS)

Yan, Xin; Zhang, Xia; Li, Junshuai; Cui, Jiangong; Ren, Xiaomin

2014-01-01

The growth and optical properties of InP and InP/InAs nanostructures on GaAs nanowires are investigated. InP quantum well and quantum dots (QDs) are formed on the sidewalls of GaAs nanowires successively with increasing the deposition time of InP. The GaAs/InP nanowire heterostructure exhibits a type-II band alignment. The wavelength of the InP quantum well is in the range of 857–892 nm at 77 K, which means that the quantum well is nearly fully strained. The InP quantum dot, which has a bow-shaped cross section, exhibits dislocation-free pure zinc blende structure. Stranski-Krastanow InAs quantum dots are subsequently formed on the GaAs/InP nanowire core-shell structure. The InAs quantum dots are distributed over the middle part of the nanowire, indicating that the In atoms contributing to the quantum dots mainly come from the vapor rather than the substrate. The longest emission wavelength obtained from the InAs QDs is 1039 nm at 77 K. The linewidth is as narrow as 46.3 meV, which is much narrower than those on planar InP substrates and wurtzite InP nanowires, suggesting high-crystal-quality, phase-purity, and size-uniformity of quantum dots

Zone refining high-purity germanium

International Nuclear Information System (INIS)

Hubbard, G.S.; Haller, E.E.; Hansen, W.L.

1977-10-01

The effects of various parameters on germanium purification by zone refining have been examined. These parameters include the germanium container and container coatings, ambient gas and other operating conditions. Four methods of refining are presented which reproducibly yield 3.5 kg germanium ingots from which high purity (vertical barN/sub A/ - N/sub D/vertical bar less than or equal to2 x 10 10 cm -3 ) single crystals can be grown. A qualitative model involving binary and ternary complexes of Si, O, B, and Al is shown to account for the behavior of impurities at these low concentrations

Preserving high-purity 233U

International Nuclear Information System (INIS)

Krichinsky, Alan; Giaquinto, Joe; Canaan, Doug

2016-01-01

The MARC X Conference hosted a workshop for the scientific community to communicate needs for high-purity 233 U and its by-products in order to preserve critical items otherwise slated for downblending and disposal. Currently, only small portions of the U.S. holdings of separated 233 U are being preserved. However, many additional kilograms of 233 U (>97 % pure) still are destined to be disposed, and it is unlikely that this material will ever be replaced due to a lack of operating production capability. Summaries of information conveyed at the workshop and feedback obtained from the scientific community are presented herein. (author)

Tunable Seed Lasers for Laser Remote Sensing of CO2 and O2, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Vescent Photonics propose to develop a chip-sized narrow linewidth ( 10 nm's) diode laser that will be suitable for a wide variety of NASA remote sensing missions....

Fast and accurate expression for the Voigt function. Application to the determination of uranium M linewidths

International Nuclear Information System (INIS)

Limandri, Silvina P.; Bonetto, Rita D.; Di Rocco, Hector O.; Trincavelli, Jorge C.

2008-01-01

The Voigt function is the convolution between a Gaussian and a Lorentzian distribution. The numerical implementation of this function is required in diverse areas of physics and applied mathematics. An explicit representation for the Voigt function is developed in terms of series of trigonometric and hyperbolic functions. The obtained expression permits a very fast evaluation of Voigt profiles with a degree of accuracy higher than the one required for spectroscopy applications. In addition, this expression is implemented in a numerical algorithm of parameter optimization in electron probe microanalysis, and applied to determine natural linewidths for several transitions to the uranium M levels

Fast and accurate expression for the Voigt function. Application to the determination of uranium M linewidths

Energy Technology Data Exchange (ETDEWEB)

Limandri, Silvina P. [Facultad de Matematica, Astronomia y Fisica, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000, Cordoba (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas de la Republica Argentina (Argentina); Bonetto, Rita D. [Consejo Nacional de Investigaciones Cientificas y Tecnicas de la Republica Argentina (Argentina) and Centro de Investigacion y Desarrollo en Ciencias Aplicadas Dr. Jorge Ronco, Calle 47 No 257, 1900 La Plata, Argentina; Facultad de Ciencias Exactas y Facultad de Ingenieria de la UNLP, La Plata (Argentina); Di Rocco, Hector O. [Consejo Nacional de Investigaciones Cientificas y Tecnicas de la Republica Argentina (Argentina); Instituto de Fisica Arroyo Seco, Facultad de Ciencias Exactas, Universidad Nacional del Centro, Pinto 399, 7000 Tandil (Argentina); Trincavelli, Jorge C. [Facultad de Matematica, Astronomia y Fisica, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000, Cordoba (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas de la Republica Argentina (Argentina)], E-mail: jorge@quechua.fis.uncor.edu

2008-09-15

The Voigt function is the convolution between a Gaussian and a Lorentzian distribution. The numerical implementation of this function is required in diverse areas of physics and applied mathematics. An explicit representation for the Voigt function is developed in terms of series of trigonometric and hyperbolic functions. The obtained expression permits a very fast evaluation of Voigt profiles with a degree of accuracy higher than the one required for spectroscopy applications. In addition, this expression is implemented in a numerical algorithm of parameter optimization in electron probe microanalysis, and applied to determine natural linewidths for several transitions to the uranium M levels.

Analysis technique of impurity in high purity deuterium by cryogenic gas-chromatography

International Nuclear Information System (INIS)

Zhou Junbo; Gao Liping

2007-01-01

A veracious and applicable quantitative analysis method of O 2 , N 2 and H 2 , HD in high purity deuterium by the chromatogram columniation filled with 5A molecular sieve and alumina was researched and constituted at natural temperature and 77 K, respectively. Minimum detecting limit of the present method is (150-200) x 10 -6 for H 2 and HD, and it can meet the need of quantitative analysis of the impurity during high purity deuterium preparation. (authors)

Ehrenfest dynamics is purity non-preserving: A necessary ingredient for decoherence

International Nuclear Information System (INIS)

Alonso, J. L.; Clemente-Gallardo, J.; Cuchí, J. C.

2012-01-01

We discuss the evolution of purity in mixed quantum/classical approaches to electronic nonadiabatic dynamics in the context of the Ehrenfest model. As it is impossible to exactly determine initial conditions for a realistic system, we choose to work in the statistical Ehrenfest formalism that we introduced in Alonso et al. [J. Phys. A: Math. Theor. 44, 396004 (2011)]. From it, we develop a new framework to determine exactly the change in the purity of the quantum subsystem along with the evolution of a statistical Ehrenfest system. In a simple case, we verify how and to which extent Ehrenfest statistical dynamics makes a system with more than one classical trajectory, and an initial quantum pure state become a quantum mixed one. We prove this numerically showing how the evolution of purity depends on time, on the dimension of the quantum state space D, and on the number of classical trajectories N of the initial distribution. The results in this work open new perspectives for studying decoherence with Ehrenfest dynamics.

A fast switch, combiner and narrow-band filter for high-power millimetre wave beams

Science.gov (United States)

Kasparek, W.; Petelin, M. I.; Shchegolkov, D. Yu; Erckmann, V.; Plaum, B.; Bruschi, A.; ECRH Groups at IPP Greifswald; Karlsruhe, FZK; Stuttgart, IPF

2008-05-01

A fast directional switch (FADIS) is described, which allows controlled switching of high-power microwaves between two outputs. A possible application could be synchronous stabilization of neoclassical tearing modes (NTMs). Generally, the device can be used to share the installed EC power between different types of launchers or different applications (e.g. in ITER, midplane/upper launcher). The switching is performed electronically without moving parts by a small frequency-shift keying of the gyrotron (some tens of megahertz), and a narrow-band diplexer. The device can be operated as a beam combiner also, which offers attractive transmission perspectives in multi-megawatt ECRH systems. In addition, these diplexers are useful for plasma diagnostic systems employing high-power sources due to their filter characteristics. The principle and the design of a four-port quasi-optical resonator diplexer is presented. Low-power measurements of switching contrast, mode purity and efficiency show good agreement with theory. Preliminary frequency modulation characteristics of gyrotrons are shown, and first results from high-power switching experiments using the ECRH system for W7-X are presented.

A fast switch, combiner and narrow-band filter for high-power millimetre wave beams

International Nuclear Information System (INIS)

Kasparek, W.; Plaum, B.; Petelin, M.I.; Shchegolkov, D.Yu; Erckmann, V.; Bruschi, A.

2008-01-01

A fast directional switch (FADIS) is described, which allows controlled switching of high-power microwaves between two outputs. A possible application could be synchronous stabilization of neoclassical tearing modes (NTMs). Generally, the device can be used to share the installed EC power between different types of launchers or different applications (e.g. in ITER, midplane/upper launcher). The switching is performed electronically without moving parts by a small frequency-shift keying of the gyrotron (some tens of megahertz), and a narrow-band diplexer. The device can be operated as a beam combiner also, which offers attractive transmission perspectives in multi-megawatt ECRH systems. In addition, these diplexers are useful for plasma diagnostic systems employing high-power sources due to their filter characteristics. The principle and the design of a four-port quasi-optical resonator diplexer is presented. Low-power measurements of switching contrast, mode purity and efficiency show good agreement with theory. Preliminary frequency modulation characteristics of gyrotrons are shown, and first results from high-power switching experiments using the ECRH system for W7-X are presented

Voltage-controlled colour-tunable microcavity OLEDs with enhanced colour purity

International Nuclear Information System (INIS)

Choy, Wallace C H; Niu, J H; Li, W L; Chui, P C

2008-01-01

The emission spectrum of single-unit voltage-controlled colour-tunable organic light emitting devices (OLEDs) has been theoretically and experimentally studied. Our results show that by introducing the microcavity structure, the colour purity of not only the destination colour but also the colour-tunable route can be enhanced, while colour purity is still an issue in typical single-unit voltage-controlled colour-tunable OLEDs. With the consideration of the periodical cycling of resonant wavelength and absorption loss of the metal electrodes, the appropriate change in the thickness of the microcavity structure has been utilized to achieve voltage-controlled red-to-green and red-to-blue colour-tunable OLEDs without adding dyes or other organic materials to the OLEDs

The analytical of radiochemical purity of tumor receptor imaging agent 99Tcm-octreotide

International Nuclear Information System (INIS)

Wang Xufu; Zuo Shuyao; Shao Wenbo; Wang Guoming; Sun Jianwen; Zhang Qin

2003-01-01

The radiochemical purity of tumor receptor imaging agent 99 Tc m -octreotide is measured by High Pressure Liquid Chromatography (HPLC) and two systems of chromatography combining method of silver stain. The results show that the radiochemical purity of 98 Tc m -octreotide measured by both methods are effective and correct. It can separate 99 Tc m -octreotide from other radioactive compositions correctly and effectively

Thermal fluctuations in resonant motion of fluxons on a Josephson transmission line: Theory and experiment

DEFF Research Database (Denmark)

Jørgensen, E.; Koshelets, V. P.; Monaco, Roberto

1982-01-01

The radiation emission from long and narrow Josephson tunnel junctions dc-current biased on zero-field steps has been ascribed to resonant motion of fluxons on the transmission line. Within this dynamic model a theoretical expression for the radiation linewidth is derived from a full statistical ...... treatment of thermal fluctuations in the fluxon velocity. The result appears to be very general and is corroborated by experimental determination of linewidth and frequency of radiation emitted from overlap Nb-I-Pb junctions....

Self-pulsing in a 2 km single-mode fiber with the seed source broadened via WNS phase modulation

Science.gov (United States)

Zha, Congwen; Sun, Yinhong; Wang, Yanshan; Li, Tenglong; Peng, Wanjing; Ma, Yi; Zhang, Kai

2018-03-01

The seed source with spectral linewidth broadening via phase modulation is potential to achieve the higher output power with effective SBS suppression. However, self-pulsing from the amplifier output is harmful. In this work, we study the self-pulsing characteristics in a long single-mode fiber with lower self-pulsing threshold instead of the high power amplifier. We provide a powerful experimental support for the self-pulsing mechanism in high-power narrow-linewidth fiber lasers, which is important for further output power scaling.

Evaluation of radiochemical purities of some radiopharmaceuticals in Shiraz Namazi teaching hospital

Directory of Open Access Journals (Sweden)

Hossein Sadeghpour

2015-03-01

Full Text Available Many radiopharmaceuticals, as a special group of drugs, are eventually prepared at the nuclear medicine departments of the hospitals. Therefore, their quality control procedures such as sterility tests, radionuclide, radiochemical and chemical purity should be carried out in the hospitals. In this study, radiochemical purity for more than 300 preparations of three different radiopharmaceutical formulations from commercial kits were tested using instant thin layer chromatography. The formulations 99mTc-DTPA, 99mTc-MDP and 99mTc-MIBI were obtained from Pars Isotope Co. Several paper chromatographic systems including standard and factory recommended thin layer chromatography systems were used in this study. In addition different equipments for detection of radioactivity in paper chromatography like gamma camera and dose calibrator were used. The results showed that the most observed impurities were hydrolyzed reduced technetium (HR-Tc. There were no significant differences between calculated 99mTc-MIBI radiochemical purities when the radioactive detection device was gamma camera instead of dose calibrator. In case of 99mTc-DTPA and 99mTc-MDP, there were significant differences in detection of HR-Tc. On the contrary, no significant differences in free pertechnetate were observed when package insert procedures for quality control were used instead of those recommended in the references. Finally, we observed that the package insert procedures for quality control can offer higher radiochemical purities.

High purity neodymium acetate from mixed rare earth carbonates

International Nuclear Information System (INIS)

Queiroz, Carlos A. da Silva; Rocha, Soraya M. Rizzo da; Vasconcellos, Mari E. de; Lobo, Raquel M.; Seneda, Jose A.; Pedreira, Walter dos R.

2011-01-01

A simple and economical chemical process for obtaining high purity neodymium acetate is discussed. The raw material in the form rare earth carbonate is produced industrially from the chemical treatment of Brazilian monazite. Ion exchange chromatography technique with a strong cationic resin, proper to water treatment, and without the use of retention ions was used for the fractionating of the rare earth elements (REE). In this way, it was possible to obtain 99.9% pure Nd 2 O 3 in yields greater than or equal 80%, with the elution of the REE using ammonium salt of ethylenediaminetetraacetic acid (EDTA) solution in pH controlled. The complex of EDTA-neodymium was transformed into neodymium oxide, which was subsequently dissolved in acetic acid to obtain the neodymium acetates. Molecular absorption spectrophotometry was used to monitor the neodymium content during the process and sector field inductively coupled plasma mass spectrometry was used to certify the purity of the neodymium acetates. The typical neodymium acetates obtained contain the followings contaminants in μg g -1 : Sc(5.1); Y (0.9); La (1.0); Ce (6.1); Pr (34,4); Sm (12.8); Eu (1.1); Gd (15.4); Tb (29.3); Dy (5.2), Ho(7.4); Er (14.6); Tm (0.3); Yb (2.5); Lu (1.0). The high purity neodymium acetates obtained from this procedure have been applied, replacing the imported product, in research and development area on rare earth catalysts. (author)

Enhanced color purity of blue OLEDs based on well-design structure

Science.gov (United States)

Du, Qianqian; Wang, Wenjun; Li, Shuhong; Wang, Qingru; Xia, Shuzhen; Zhang, Bingyuan; Wang, Minghong; Fan, Quli

2016-09-01

We have fabricated blue organic light-emitting devices (OLEDs) with higher color purity and stability by optimizing the structure of the Glass/ITO/NPB(50 nm)/ BCzVBi (30 nm)/ TPBi (x nm)/Alq3(20 nm)/LiF/Al. The results show that the introducing of hole blocking layer(HBL) TPBi greatly can improve not only the color purity but the color stability, which owe to its higher the Highest Occupied Molecular Orbital (HOMO) energy levels of 6.2 eV. We expect our work will be useful to optimizing the blue OLEDs structure to enhancing the color property.

On-demand semiconductor source of 780-nm single photons with controlled temporal wave packets

Science.gov (United States)

Béguin, Lucas; Jahn, Jan-Philipp; Wolters, Janik; Reindl, Marcus; Huo, Yongheng; Trotta, Rinaldo; Rastelli, Armando; Ding, Fei; Schmidt, Oliver G.; Treutlein, Philipp; Warburton, Richard J.

2018-05-01

We report on a fast, bandwidth-tunable single-photon source based on an epitaxial GaAs quantum dot. Exploiting spontaneous spin-flip Raman transitions, single photons at 780 nm are generated on demand with tailored temporal profiles of durations exceeding the intrinsic quantum dot lifetime by up to three orders of magnitude. Second-order correlation measurements show a low multiphoton emission probability [g2(0 ) ˜0.10 -0.15 ] at a generation rate up to 10 MHz. We observe Raman photons with linewidths as low as 200 MHz, which is narrow compared to the 1.1-GHz linewidth measured in resonance fluorescence. The generation of such narrow-band single photons with controlled temporal shapes at the rubidium wavelength is a crucial step towards the development of an optimized hybrid semiconductor-atom interface.

JOYO coolant sodium and cover gas purity control database (MK-II core)

International Nuclear Information System (INIS)

Ito, Kazuhiro; Nemoto, Masaaki

2000-03-01

The experimental fast reactor 'JOYO' served as the MK-II irradiation bed core for testing fuel and material for FBR development for 15 years from 1982 to 1997. During the MK-II operation, impurities concentrations in the sodium and the argon gas were determined by 67 samples of primary sodium, 81 samples of secondary sodium, 75 samples of primary argon gas, 89 samples of secondary argon gas (the overflow tank) and 89 samples of secondary argon gas (the dump tank). The sodium and the argon gas purity control data were accumulated from in thirty-one duty operations, thirteen special test operations and eight annual inspections. These purity control results and related plant data were compiled into database, which were recorded on CD-ROM for user convenience. Purity control data include concentration of oxygen, carbon, hydrogen, nitrogen, chlorine, iron, nickel and chromium in sodium, concentration of oxygen, hydrogen, nitrogen, carbon dioxide, methane and helium in argon gas with the reactor condition. (author)

Tunable high-power narrow-linewidth green external-cavity GaN diode laser

DEFF Research Database (Denmark)

Chi, Mingjun; Jensen, Ole Bjarlin; Petersen, Paul Michael

2016-01-01

A tunable high-power green external-cavity diode laser is demonstrated. Up to 290 mW output power and a 9.2 nm tuning is achieve. This constitutes the highest output power from a tunable green diode laser system.......A tunable high-power green external-cavity diode laser is demonstrated. Up to 290 mW output power and a 9.2 nm tuning is achieve. This constitutes the highest output power from a tunable green diode laser system....

Dense arrays of ordered pyramidal quantum dots with narrow linewidth photoluminescence spectra

Energy Technology Data Exchange (ETDEWEB)

Surrente, A; Gallo, P; Felici, M; Dwir, B; Rudra, A; Kapon, E, E-mail: alessandro.surrente@epfl.c [Laboratory of Physics of Nanostructures, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

2009-10-14

Arrays of site-controlled, pyramidal InGaAs/GaAs quantum dots (QDs) grown by organo-metallic chemical vapour deposition with densities comparable to those of self-assembled QDs (5 x 10{sup 9} cm{sup -2}) are demonstrated. The QDs exhibit high quality photoluminescence spectra with inhomogeneous broadening of only 6.5 meV. The QD dipole moment was estimated through the analysis of time-resolved photoluminescence measurements. Such ordered QD arrays should be useful for applications in active nanophotonic systems such as QD lasers, modulators and switches requiring high overlap of the optical modes with the QD active region.

Corrosion of high purity Fe-Cr-Ni alloys in 13 N boiling nitric acid

International Nuclear Information System (INIS)

Ohta, Joji; Mayuzumi, Masami; Kusanagi, Hideo; Takaku, Hiroshi

1998-01-01

Corrosion in boiling nitric acid was investigated for high purity Fe-18%Cr-12%Ni alloys and type 304L stainless steels (SS). Owing to very low impurity concentration, the solution treated high purity alloys show almost no intergranular corrosion while the type 304L SS show severe intergranular corrosion. Both in the high purity alloys and type 304L SS, aging treatments ranging from 873 K to 1073 K for 1 h enhance intergranular corrosion. During the aging treatments, impurities should be segregated to the grain boundaries. The corrosion behaviors were discussed from a standpoint of impurity segregation to grain boundaries. This study is of importance for purex reprocessing of spent fuels

Filtered Rayleigh Scattering Measurements in a Buoyant Flow Field

National Research Council Canada - National Science Library

Meents, Steven M

2008-01-01

Filtered Rayleigh Scattering (FRS) is a non-intrusive, laser-based flow characterization technique that consists of a narrow linewidth laser, a molecular absorption filter, and a high resolution camera behind the filter to record images...

Capillary electrophoresis-based assessment of nanobody affinity and purity

NARCIS (Netherlands)

Haselberg, Rob; Oliveira, Sabrina; van der Meel, Roy; Somsen, Govert W; de Jong, Gerhardus J

2014-01-01

Drug purity and affinity are essential attributes during development and production of therapeutic proteins. In this work, capillary electrophoresis (CE) was used to determine both the affinity and composition of the biotechnologically produced "nanobody" EGa1, the binding fragment of a

Purity of targets prepared on Cu substrates

Science.gov (United States)

Méens, A.; Rossini, I.; Sens, J. C.

1993-09-01

The purity of several elemental self-supporting targets usually prepared by evaporation onto soluble Cu substrates has been studied. The targets were analysed by Rutherford backscattering and instrumental neutron activation analysis. Because of the high percentage of Cu observed in some Si targets, further measurements, including transmission electron microscopy, have been performed on Si targets deposited by e-gun bombardment onto Cu and ion-beam sputtering onto betaine.

Imaging Scanner Usage in Radiochemical Purity Test

International Nuclear Information System (INIS)

Norhafizah Othman; Yahaya Talib; Wan Hamirul Bahrin Wan Kamal

2011-01-01

Imaging Scanner model BIOSCAN AR-2000 has been used in the radiochemical purity test for the product of Mo-99/ Tc-99m generator. Result from this test was produced directly where the percentage of pertechnetate was calculated based on width peak area by thin layer chromatography. This paperwork will explain the function, procedure, calibration of the instrument and discussed the advantages compared to the previous method. (author)

Jihadism, Narrow and Wide

DEFF Research Database (Denmark)

Sedgwick, Mark

2015-01-01

The term “jihadism” is popular, but difficult. It has narrow senses, which are generally valuable, and wide senses, which may be misleading. This article looks at the derivation and use of “jihadism” and of related terms, at definitions provided by a number of leading scholars, and at media usage....... It distinguishes two main groups of scholarly definitions, some careful and narrow, and some appearing to match loose media usage. However, it shows that even these scholarly definitions actually make important distinctions between jihadism and associated political and theological ideology. The article closes...

Device Physics of Narrow Gap Semiconductors

CERN Document Server

Chu, Junhao

2010-01-01

Narrow gap semiconductors obey the general rules of semiconductor science, but often exhibit extreme features of these rules because of the same properties that produce their narrow gaps. Consequently these materials provide sensitive tests of theory, and the opportunity for the design of innovative devices. Narrow gap semiconductors are the most important materials for the preparation of advanced modern infrared systems. Device Physics of Narrow Gap Semiconductors offers descriptions of the materials science and device physics of these unique materials. Topics covered include impurities and defects, recombination mechanisms, surface and interface properties, and the properties of low dimensional systems for infrared applications. This book will help readers to understand not only the semiconductor physics and materials science, but also how they relate to advanced opto-electronic devices. The last chapter applies the understanding of device physics to photoconductive detectors, photovoltaic infrared detector...

Hydrogen concentration and distribution in high-purity germanium crystals

International Nuclear Information System (INIS)

Hansen, W.L.; Haller, E.E.; Luke, P.N.

1981-10-01

High-purity germanium crystals used for making nuclear radiation detectors are usually grown in a hydrogen ambient from a melt contained in a high-purity silica crucible. The benefits and problems encountered in using a hydrogen ambient are reviewed. A hydrogen concentration of about 2 x 10 15 cm -3 has been determined by growing crystals in hydrogen spiked with tritium and counting the tritium β-decays in detectors made from these crystals. Annealing studies show that the hydrogen is strongly bound, either to defects or as H 2 with a dissociation energy > 3 eV. This is lowered to 1.8 eV when copper is present. Etching defects in dislocation-free crystals grown in hydrogen have been found by etch stripping to have a density of about 1 x 10 7 cm -3 and are estimated to contain 10 8 H atoms each

Scalable preparation of high purity rutin fatty acid esters following enzymatic synthesis

DEFF Research Database (Denmark)

Lue, Bena-Marie; Guo, Zheng; Xu, Xuebing

2010-01-01

Investigations into expanded uses of modified flavonoids are often limited by the availability of these high purity compounds. As such, a simple, effective and relatively fast method for isolation of gram quantities of both long and medium chain fatty acid esters of rutin following scaled......-up biosynthesis reactions was established. Acylation reactions of rutin and palmitic or lauric acids were efficient in systems containing dried acetone and molecular sieves, yielding from 70–77% bioconversion after 96 h. Thereafter, high purity isolates (>97%) were easily obtained in significant quantities...

Polarimetric purity and the concept of degree of polarization

Science.gov (United States)

Gil, José J.; Norrman, Andreas; Friberg, Ari T.; Setälä, Tero

2018-02-01

The concept of degree of polarization for electromagnetic waves, in its general three-dimensional version, is revisited in the light of the implications of the recent findings on the structure of polarimetric purity and of the existence of nonregular states of polarization [J. J. Gil et al., Phys Rev. A 95, 053856 (2017), 10.1103/PhysRevA.95.053856]. From the analysis of the characteristic decomposition of a polarization matrix R into an incoherent convex combination of (1) a pure state Rp, (2) a middle state Rm given by an equiprobable mixture of two eigenstates of R, and (3) a fully unpolarized state Ru -3 D, it is found that, in general, Rm exhibits nonzero circular and linear degrees of polarization. Therefore, the degrees of linear and circular polarization of R cannot always be assigned to the single totally polarized component Rp. It is shown that the parameter P3 D proposed formerly by Samson [J. C. Samson, Geophys. J. R. Astron. Soc. 34, 403 (1973), 10.1111/j.1365-246X.1973.tb02404.x] takes into account, in a proper and objective form, all the contributions to polarimetric purity, namely, the contributions to the linear and circular degrees of polarization of R as well as to the stability of the plane containing its polarization ellipse. Consequently, P3 D constitutes a natural representative of the degree of polarimetric purity. Some implications for the common convention for the concept of two-dimensional degree of polarization are also analyzed and discussed.

Polymer laser bio-sensors

DEFF Research Database (Denmark)

Kristensen, Anders; Vannahme, Christoph; Hermannsson, Pétur Gordon

2014-01-01

Organic dye based distributed feed-back lasers, featuring narrow linewidth and thus high quality spectral resolution, are used as highly sensitive refractive index sensors. The design, fabrication and application of the laser intra-cavity sensors are discussed....

Narrow dibaryon resonances

International Nuclear Information System (INIS)

Kajdalov, A.B.

1986-01-01

Experimental data on np interactions indicating to existence of narrow resonances in pp-system are discussed. Possible theoretical interpretations of these resonances are given. Experimental characteristics of the dibaryon resonances with isospin I=2 are considered

Policosanol extraction from beeswax and improvement of the purity

Directory of Open Access Journals (Sweden)

Srisaipet Anakhaorn

2017-01-01

Full Text Available Policosanol is a mixture of high molecular weight aliphatic long chain alcohols (20-36 carbon atoms. It has been use in pharmaceutical composition and food supplements. This research aimed to isolate and improve the purity of policosanol extracted from beeswax. Triglycerides and other impurities were eliminated from beeswax by refluxing with hexane followed by isopropanol. The purified beeswax was hydrolyzed by refluxing with 1 M ethanolic NaOH for 2 hours. Purification of policosanol was performed by extracting the hydrolyzed product with acetone at 50-60 °C for 3 hours and it was stored at 4 °C for precipitation. The precipitate was refluxed with heptanes followed by washing with hot water. The heptanes layer was kept for policosanol precipitation at 4 °C. The purity of policosanol was confirmed by TLC and high performance liquid chromatography (HPLC. The yield of purified policosanol was 13.23-13.89 %.

Electrophoresis for the analysis of heparin purity and quality.

Science.gov (United States)

Volpi, Nicola; Maccari, Francesca; Suwan, Jiraporn; Linhardt, Robert J

2012-06-01

The adulteration of raw heparin with oversulfated chondroitin sulfate (OSCS) in 2007-2008 produced a global crisis resulting in extensive revisions to the pharmacopeia monographs and prompting the FDA to recommend the development of additional methods for the analysis of heparin purity. As a consequence, a wide variety of innovative analytical approaches have been developed for the quality assurance and purity of unfractionated and low-molecular-weight heparins. This review discusses recent developments in electrophoresis techniques available for the sensitive separation, detection, and partial structural characterization of heparin contaminants. In particular, this review summarizes recent publications on heparin quality and related impurity analysis using electrophoretic separations such as capillary electrophoresis (CE) of intact polysaccharides and hexosamines derived from their acidic hydrolysis, and polyacrylamide gel electrophoresis (PAGE) for the separation of heparin samples without and in the presence of its relatively specific depolymerization process with nitrous acid treatment. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison of rigorous modelling of different structure profiles on photomasks for quantitative linewidth measurements by means of UV- or DUV-optical microscopy

Science.gov (United States)

Ehret, Gerd; Bodermann, Bernd; Woehler, Martin

2007-06-01

The optical microscopy is an important instrument for dimensional characterisation or calibration of micro- and nanostructures, e.g. chrome structures on photomasks. In comparison to scanning electron microscopy (possible contamination of the sample) and atomic force microscopy (slow, risk of damage) optical microscopy is a fast and non destructive metrology method. The precise quantitative determination of the linewidth from the microscope image is, however, only possible by knowledge of the geometry of the structures and their consideration in the optical modelling. We compared two different rigorous model approaches, the Rigorous Coupled Wave Analysis (RCWA) and the Finite Elements Method (FEM) for modelling of structures with different edge angles, linewidths, line to space ratios and polarisations. The RCWA method can adapt inclined edges profiles only by a staircase approximation leading to increased modelling errors of the RCWA method. Even today's sophisticated rigorous methods still show problems with TM-polarisation. Therefore both rigorous methods are compared in terms of their convergence for TE and TM- polarisation. Beyond that also the influence of typical illumination wavelengths (365 nm, 248 nm and 193 nm) on the microscope images and their contribution to the measuring uncertainty budget will be discussed.

Isolation of high purity americium metal via distillation

Science.gov (United States)

Squires, Leah N.; King, James A.; Fielding, Randall S.; Lessing, Paul

2018-03-01

Pure americium metal is a crucial component for the fabrication of transmutation fuels. Unfortunately, americium in pure metal form is not available; however, a number of mixed metals and mixed oxides that include americium are available. In this manuscript a method is described to obtain high purity americium metal from a mixture of americium and neptunium metals with lead impurity via distillation.

A diode-laser optical frequency standard based on laser-cooled Ca atoms: sub-kilohertz spectroscopy by optical shelving detection

International Nuclear Information System (INIS)

Oates, C.W.; Bondu, F.; Fox, R.W.; Hollberg, L.

1999-01-01

We report an optical frequency standard at 657 nm based on laser-cooled/trapped Ca atoms. The system consists of a novel, compact magneto-optic trap which uses 50 mW of frequency-doubled diode laser light at 423 nm and can trap >10 7 Ca atoms in 20 ms. High resolution spectroscopy on this atomic sample using the narrow 657 nm intercombination line resolves linewidths (FWHM) as narrow as 400 Hz, the natural linewidth of the transition. The spectroscopic signal-to-noise ratio is enhanced by an order of magnitude with the implementation of a ''shelving'' detection scheme on the 423 nm transition. Our present apparatus achieves a fractional frequency instability of 5 x 10 -14 in 1 s with a potential atom shot-noise-limited performance of 10 -16 τ -1/2 and excellent prospects for high accuracy. (orig.)

Note on the polishing of small spheres of ferrimagnetic materials

Energy Technology Data Exchange (ETDEWEB)

Grunberg, J. G.; Antier, G. [Centre d' etudes nucleaires de Grenoble - C.E.N.G. (France); Seiden, P. E. [Institut Fourier, Universite de Grenoble (France)

1961-07-01

This note describes a simple and rapid method that we have used for obtaining a high degree of polish on spheres of ferrimagnetic materials. A high surface polish is of particular importance if one desires to perform ferrimagnetic resonance experiments on very narrow linewidth materials such as Yttrium Iron Garnet. It is not possible to obtain the very narrow linewidths without polishing the sample with a very fine abrasive such as 'Linde A'. Although the methods presently used for the fine polishing of ferrite spheres give satisfactory results, the method described here is of particular interest because of its simplicity and speed. For example with the air-jet tumbling technique it can take as long as three days of polishing to obtain an acceptable surface while our method will give the same results in one to two hours. (author)

A superconducting phase-locked local oscillator for a submillimetre integrated receiver

International Nuclear Information System (INIS)

Koshelets, V P; Shitov, S V; Filippenko, L V; Dmitriev, P N; Ermakov, A B; Sobolev, A S; Torgashin, M Yu; Pankratov, A L; Kurin, V V; Yagoubov, P; Hoogeveen, R

2004-01-01

Comprehensive measurements of the flux flow oscillator (FFO) radiation linewidth are performed using an integrated harmonic SIS mixer; the FFO linewidth and spectral line profile are compared to a theory. An essential dependence of the FFO linewidth on frequency is found; a possible explanation is proposed. The results of the numerical solution of the perturbed sine-Gordon equation qualitatively confirm this assumption. To optimize the FFO design, the influence of the FFO parameters on the radiation linewidth is studied. A novel FFO design at a moderate current density has resulted in a free-running FFO linewidth of about 10 MHz in the flux flow regime up to 712 GHz, limited only by the gap frequency of Nb. This relatively narrow free-running linewidth (along with implementation of a wide-band phase locking loop system) allows continuous phase locking of the FFO in the wide frequency range of 500-710 GHz. These results are the basis for the development of a 550-650 GHz integrated receiver for the terahertz limb sounder (TELIS) intended for atmosphere study and scheduled to fly on a balloon in 2005. We report here also on the design of the second generation of the phase-locked superconducting integrated receiver chip for TELIS

Recovery of high-purity metallic Pd from Pd(II)-sorbed biosorbents by incineration.

Science.gov (United States)

Won, Sung Wook; Lim, Areum; Yun, Yeoung-Sang

2013-06-01

This work reports a direct way to recover metallic palladium with high purity from Pd(II)-sorbed polyethylenimine-modified Corynebacterium glutamicum biosorbent using a combined method of biosorption and incineration. This study is focused on the incineration part which affects the purity of recovered Pd. The incineration temperature and the amount of Pd loaded on the biosorbent were considered as major factors in the incineration process, and their effects were examined. The results showed that both factors significantly affected the enhancement of the recovery efficiency and purity of the recovered Pd. SEM-EDX and XRD analyses were used to confirm that Pd phase existed in the ash. As a result, the recovered Pd was changed from PdO to zero-valent Pd as the incineration temperature was increased from 600 to 900°C. Almost 100% pure metallic Pd was recovered with recovery efficiency above 99.0% under the conditions of 900°C and 136.9 mg/g. Copyright © 2013 Elsevier Ltd. All rights reserved.

Characteristics of AlN/GaN nanowire Bragg mirror grown on (001) silicon by molecular beam epitaxy

KAUST Repository

Heo, Junseok; Bhattacharya, Pallab K.; Guo, Wei; Ooi, Boon S.; Zhou, Zifan

2013-01-01

finite difference time domain technique. Ensemble nanowire microcavities with In0.3Ga 0.7N nanowires clad by AlN/GaN DBRs have also been characterized. Room temperature emission from the microcavity exhibits considerable linewidth narrowing compared

Spectroscopy of strontium Rydberg states using electromagnetically induced transparency

International Nuclear Information System (INIS)

Mauger, S; Millen, J; Jones, M P A

2007-01-01

We report on the all-optical detection of Rydberg states in an effusive atomic beam of strontium atoms using electromagnetically induced transparency (EIT). Using narrow-linewidth CW lasers we obtain an EIT linewidth of 5 MHz. To illustrate the high spectroscopic resolution offered by this method, we have measured isotope shifts of the 5s18d 1 D 2 and 5s19s 1 S 0 Rydberg states. This technique could be applied to high-resolution, non-destructive measurements of ultra-cold Rydberg gases and plasmas. (fast track communication)

Limitations of two-level emitters as nonlinearities in two-photon controlled-PHASE gates

DEFF Research Database (Denmark)

Nysteen, Anders; McCutcheon, Dara P. S.; Heuck, Mikkel

2017-01-01

We investigate the origin of imperfections in the fidelity of a two-photon controlled-PHASE gate based on two-level-emitter nonlinearities. We focus on a passive system that operates without external modulations to enhance its performance. We demonstrate that the fidelity of the gate is limited...... by opposing requirements on the input pulse width for one-and two-photon-scattering events. For one-photon scattering, the spectral pulse width must be narrow compared with the emitter linewidth, while two-photon-scattering processes require the pulse width and emitter linewidth to be comparable. We find...

Single-longitudinal-mode BEFL incorporating a Bragg grating written in EDF

Science.gov (United States)

Gao, Ya; Sun, Junqiang; Chen, Guodong; Xie, Heng

2015-06-01

A stable and tunable single-longitudinal-mode (SLM) Brillouin/Erbium fiber laser (BEFL) with narrow linewidth is proposed and experimentally demonstrated. A uniform Bragg grating written in a segment of unpumped Erbium-doped fiber (EDF) is incorporated as an auto-tracking filter to achieve SLM operation. A length of 5 m pumped EDF is used to provide both Brillouin and linear gain in the cavity. The linewidth is measured to be 18 kHz and the lasing peak power fluctuation and wavelength shift are monitored less than 0.027 dB and 2 pm respectively.

Four-wave mixing and six-wave mixing in a four-level confined atomic system

International Nuclear Information System (INIS)

Chang-Biao, Li; Yan-Peng, Zhang; Zhi-Qiang, Nie; Huai-Bin, Zheng; Mei-Zhen, Shi; Dong-Ning, Liu; Jian-Ping, Song; Ke-Qing, Lu

2009-01-01

We have investigated coexisting four-wave mixing and six-wave mixing (SWM) in ultra-thin, micrometre and long vapour cells. There exists competition between Dicke-narrowing features and polarization interference in the micrometre cell. The oscillation behaviour of SWM signal intensities and linewidths results from destructive interference. With a larger destructive interference, the SWM signal in ultra-thin cells shows a narrow spectrum, in contrast to the long cell case. Due to the Dicke-narrowing features, a narrow spectrum can be obtained, and such spectra can be used for high precision measurements and metrological standards. (classical areas of phenomenology)

Giant Magnetic Field Enhancement in Hybridized MIM Structures

KAUST Repository

Alrasheed, Salma; Di Fabrizio, Enzo M.

2017-01-01

We propose numerically an approach to narrow the plasmon linewidth and enhance the magnetic near field intensity at a magnetic hot spot in a hybridized metal-insulatormetal (MIM) structure. First we insert in part of the dielectric layer of the MIM

High purity radioactive beams at the bevalac

International Nuclear Information System (INIS)

Alonso, J.R.; Chatterjee, A.; Tobias, C.A.

1979-03-01

Peripheral nuclear fragmentation reactions of primary Bevalac heavy ion beams are used to produce secondary beams of radioactive nuclei. The large cross section and small deflection of the projectile fragments lead to high production and delivery efficiency for these beams. Dispersive beam transport allows good separation and purification of the desired secondary beams. 11 C and 19 Ne beams of high purity and good intensity (almost 0.2% of the primary beam current) are presently being used for biomedical experiments

Large-amplitude and narrow-band vibration phenomenon of a foursquare fix-supported flexible plate in a rigid narrow channel

Energy Technology Data Exchange (ETDEWEB)

Liu Lifang, E-mail: liu_lifang1106@yahoo.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); Lu Daogang, E-mail: ludaogang@ncepu.edu.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); Li Yang, E-mail: qinxiuyi@sina.com [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); Zhang Pan, E-mail: zhangpan@ncepu.edu.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); Niu Fenglei, E-mail: niufenglei@ncepu.edu.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China)

2011-08-15

Highlights: > FIV of a foursquare fix-supported flexible plate exposed to axial flow was studied. > Special designed test section and advanced measuring equipments were adopted. > The narrow-band vibration phenomenon with large amplitude was observed. > Line of plate's vibration amplitude and flow rate was investigated. > The phenomenon and the measurement error were analyzed. - Abstract: An experiment was performed to analyze the flow-induced vibration behavior of a foursquare fix-supported flexible plate exposed to the axial flow within a rigid narrow channel. The large-amplitude and narrow-band vibration phenomenon was observed in the experiment when the flow velocity varied with the range of 0-5 m/s. The occurring condition and some characteristics of the large-amplitude and narrow-band vibrations were investigated.

Electron Spin Resonance Shift and Linewidth Broadening of Nitrogen-Vacancy Centers in Diamond as a Function of Electron Irradiation Dose

OpenAIRE

Kim, Edwin; Acosta, Victor M.; Bauch, Erik; Budker, Dmitry; Hemmer, Philip R.

2009-01-01

A high-nitrogen-concentration diamond sample was subject to 200-keV electron irradiation using a transmission electron microscope. The optical and spin-resonance properties of the nitrogen-vacancy (NV) color centers were investigated as a function of the irradiation dose up to 6.4\\times1021 e-/cm2. The microwave transition frequency of the NV- center was found to shift by up to 0.6% (17.1 MHz) and the linewidth broadened with increasing electron-irradiation dose. Unexpectedly, the measured ma...

Linewidth-tolerant real-time 40-Gbit/s 16-QAM self-homodyne detection using a pilot carrier and ISI suppression based on electronic digital processing.

Science.gov (United States)

Nakamura, Moriya; Kamio, Yukiyoshi; Miyazaki, Tetsuya

2010-01-01

We experimentally demonstrate linewidth-tolerant real-time 40-Gbit/s(10-Gsymbol/s) 16-quadrature amplitude modulation. We achieved bit-error rates of noise canceling capability provided by self-homodyne detection using a pilot carrier. Pre-equalization based on digital signal processing was employed to suppress intersymbol interference caused by the limited-frequency bandwidth of electrical components.

Evolution of deformation velocity in narrowing for Zircaloy 2

Energy Technology Data Exchange (ETDEWEB)

Cetlin, P R [Minas Gerais Univ., Belo Horizonte (Brazil). Dept. de Engenharia Metalurgica; Okuda, M Y [Goias Univ., Goiania (Brazil). Inst. de Matematica e Fisica

1980-09-01

Some studies on the deformation instability in strain shows that the differences in this instability may lead to localized narrowing or elongated narrowing, for Zircaloy-2. The variation of velocity deformation with the narrowing evolution is expected to be different for these two cases. The mentioned variation is discussed, a great difference in behavior having been observed for the case of localized narrowing.

Power and polarization dependences of ultra-narrow electromagnetically induced absorption (EIA) spectra of 85 Rb atoms in degenerate two-level system

Science.gov (United States)

Qureshi, Muhammad Mohsin; Rehman, Hafeez Ur; Noh, Heung-Ryoul; Kim, Jin-Tae

2016-05-01

We have investigated ultra-narrow EIA spectral features with respect to variations of polarizations and powers of pump laser beam in a degenerate two-level system of the transition of 85 Rb D2 transition line. Polarizations of the probe laser beam in two separate experiments were fixed at right circular and horizontal linear polarizations, respectively while the polarizations of the pump lasers were varied from initial polarizations same as the probe laser beams to orthogonal to probe polarizations. One homemade laser combined with AOMs was used to the pump and probe laser beams instead of two different lasers to overcome broad linewidths of the homemade lasers. Theoretically, probe absorption coefficients have been calculated from optical Bloch equations of the degenerate two level system prepared by a pump laser beam. In the case of the circular polarization, EIA signal was obtained as expected theoretically although both pump and probe beams have same polarization. The EIA signal become smaller as power increases and polarizations of the pump and probe beams were same. When the polarization of the pump beam was linear polarization, maximum EIA signal was obtained theoretically and experimentally. Experimental EIA spectral shapes with respect to variations of the pump beam polarization shows similar trends as the theoretical results.

Disgust sensitivity is primarily associated with purity-based moral judgments

NARCIS (Netherlands)

Wagemans, F.M.A.; Brandt, M.J.; Zeelenberg, M.

2018-01-01

Individual differences in disgust sensitivity are associated with a range of judgments and attitudes related to the moral domain. Some perspectives suggest that the association between disgust sensitivity and moral judgments will be equally strong across all moral domains (i.e., purity, authority,

Narrow Networks on the Individual Marketplace in 2017.

Science.gov (United States)

Polski, Daniel; Weiner, Janet; Zhang, Yuehan

2017-09-01

This Issue Brief describes the breadth of physician networks on the ACA marketplaces in 2017. We find that the overall rate of narrow networks is 21%, which is a decline since 2014 (31%) and 2016 (25%). Narrow networks are concentrated in plans sold on state-based marketplaces, at 42%, compared to 10% of plans on federally-facilitated marketplaces. Issuers that have traditionally offered Medicaid coverage have the highest prevalence of narrow network plans at 36%, with regional/local plans and provider-based plans close behind at 27% and 30%. We also find large differences in narrow networks by state and by plan type.

High purity zirconium obtainment through the iodine compounds transport method

International Nuclear Information System (INIS)

Bolcich, J.C.; Zuzek, E.; Dutrus, S.M.; Corso, H.L.

1987-01-01

This paper describes the experimental method and the equipment designed, constructed and actually applied for the high purity zirconium obtainment from a zirconium sponge of the nuclear type. The mechanism of purification is based on the impure metal attack with gaseous iodine (at 200 deg C) to obtain zirconium tetra iodine as main product which is then transformed into a pure zirconium base (at 1000-1300 deg C), precipitating the metallic zirconium and releasing the gaseous iodine. From the first experiences carried out, pure zirconium has been obtained from an initial filament of 0.5 mm of diameter as well as wires up to 2.5 mm of diameter. This work presents the results from the studies and analysis made to characterize the material obtained. Finally, the refining methods to which the zirconium produced may be submitted so as to optimize the final purity are discussed. (Author)

Effect of relative nanohole position on colour purity of ultrathin plasmonic subtractive colour filters

International Nuclear Information System (INIS)

Sun, L B; Hu, X L; Zhang, D X; Zeng, Beibei; Wang, L S; Yang, S M; Tai, R Z; Fecht, H J; Jiang, J Z

2015-01-01

Plasmonic subtractive color filters through patterning periodic nanostructures on ultrathin Ag films deposited on a glass substrate, exhibiting good durability, simple fabrication, and flexible color tunability, have attracted considerable attention due to their tremendous potential applications. While previous studies have mainly focused on their extraordinary physical mechanisms, color purity, which is another key parameter for high quality imaging applications, has been much less investigated. In this work, we demonstrate that the relative position of nanoholes patterned on ultrathin Ag films can largely affect the color purity of plasmonic subtractive color filters. The calculated results agree reasonably well with the experimental data, revealing that the purity of subtractive colors can be improved by changing the nanohole arrays from square lattice to triangular lattice without reducing transmission at visible frequencies. In addition, underlying mechanisms are clarified by systematically analyzing the dominant valley in transmission spectra. (paper)

The effect of foil purity on morphology of anodized nanoporous ZrO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Wierzbicka, Ewa; Syrek, Karolina [Department of Physical Chemistry & Electrochemistry, Faculty of Chemistry, Jagiellonian University in Krakow, Ingardena 3, 30-060 Krakow (Poland); Sulka, Grzegorz D., E-mail: sulka@chemia.uj.edu.pl [Department of Physical Chemistry & Electrochemistry, Faculty of Chemistry, Jagiellonian University in Krakow, Ingardena 3, 30-060 Krakow (Poland); Pisarek, Marcin; Janik-Czachor, Maria [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland)

2016-12-01

Highlights: • Anodization of Zr with different purities in an aqueous electrolyte was studied. • The structural parameters of formed anodic oxides were compared. • Effect of Zr foil purity on the hexagonal arrangement of pores and cells in anodic ZrO{sub 2} was investigated. • Current efficiency and rate of anodic oxide formation were estimated. - Abstract: A two-step electrochemical formation of nanoporous zirconium oxide layers on different zirconium foils (purity 99.2% and 99.8%) was investigated. Anodizations were carried out at 20 V in an electrolyte composed of 1 M (NH{sub 4}){sub 2}SO{sub 4} and 0.15 M NH{sub 4}F. It was found that the thickness of grown oxide layer, and consequently, the rate of oxide formation depend slightly on the Zr substrate purity. The pore nucleation and anodization process occur easier in the presence of higher concentration of impurities. From top view SEM images, the structural parameters of oxide layers such as pore diameter, interpore distance, pore density, wall thickness and porosity of anodic oxide layers were estimated for both types of used substrates. On the other hand, cell size, intercell distance and cell density were evaluated from the bottom side of anodic oxide layers. A special emphasis was put on the qualitative analysis of hexagonal arrangement of nanopores and cells. The nanopore and cells arrangements in formed oxides were evaluated using various approaches based on Delaunay triangulations, angular distribution functions (ADFs) and pair distribution functions (PDFs). These results were supported by calculations of percentage of defective pores and cells for both types of used Zr substrates. The use of low purity Zr for anodizing does not affect drastically the morphology of formed nanoporous zirconia and offers a promising perspective to reduce production costs and increase availability of this material.

Coherent Protein Dynamics Explored at FELIX

CERN Document Server

Austin, Robert

2004-01-01

We have discovered that there exists a very narrow (less than 0.02 microns) wide resonance in the amide I band of myoglobin and photoactive yellow protein that can be driven to greater than 30% saturation using very narrow linewidth pump-probe spectroscopy at FELIX. The extraordinary narrowness of this transition and the extraordinary ease of saturation inplies that this band is highly anharmonic and decoupled from the other oscillators in the amide I band. We will present detailed measurments on this discovery and implications for energy flow in proteins.

Almost purity for overconvergent Witt vectors

DEFF Research Database (Denmark)

Davis, Christopher James; Kedlaya, Kiran

2015-01-01

 . Here, we use almost purity to lift the finite étale extension of R[p−1]R[p−1] to a finite étale extension of rings of overconvergent Witt vectors. The point is that no hypothesis of p-adic completeness is needed; this result thus points towards potential global analogues of p  -adic Hodge theory....... As an illustration, we construct (φ,Γ)(φ,Γ)-modules associated with Artin Motives over QQ. The (φ,Γ)(φ,Γ)-modules we construct are defined over a base ring which seems well-suited to generalization to a more global setting; we plan to pursue such generalizations in later work....

Enhanced Lamb dip for absolute laser frequency stabilization

Science.gov (United States)

Siegman, A. E.; Byer, R. L.; Wang, S. C.

1972-01-01

Enhanced Lamb dip width is 5 MHz and total depth is 10 percent of peak power. Present configuration is useful as frequency standard in near infrared. Technique extends to other lasers, for which low pressure narrow linewidth gain tubes can be constructed.

Efficient 1.6 Micron Laser Source for Methane DIAL

Science.gov (United States)

Shuman, Timothy; Burnham, Ralph; Nehrir, Amin R.; Ismail, Syed; Hair, Johnathan W.

2013-01-01

Methane is a potent greenhouse gas and on a per molecule basis has a warming influence 72 times that of carbon dioxide over a 20 year horizon. Therefore, it is important to look at near term radiative effects due to methane to develop mitigation strategies to counteract global warming trends via ground and airborne based measurements systems. These systems require the development of a time-resolved DIAL capability using a narrow-line laser source allowing observation of atmospheric methane on local, regional and global scales. In this work, a demonstrated and efficient nonlinear conversion scheme meeting the performance requirements of a deployable methane DIAL system is presented. By combining a single frequency 1064 nm pump source and a seeded KTP OPO more than 5 mJ of 1.6 µm pulse energy is generated with conversion efficiencies in excess of 20%. Even without active cavity control instrument limited linewidths (50 pm) were achieved with an estimated spectral purity of 95%. Tunable operation over 400 pm (limited by the tuning range of the seed laser) was also demonstrated. This source demonstrated the critical needs for a methane DIAL system motivating additional development of the technology.

Lasing by driven atoms-cavity system in collective strong coupling regime.

Science.gov (United States)

Sawant, Rahul; Rangwala, S A

2017-09-12

The interaction of laser cooled atoms with resonant light is determined by the natural linewidth of the excited state. An optical cavity is another optically resonant system where the loss from the cavity determines the resonant optical response of the system. The near resonant combination of an optical Fabry-Pérot cavity with laser cooled and trapped atoms couples two distinct optical resonators via light and has great potential for precision measurements and the creation of versatile quantum optics systems. Here we show how driven magneto-optically trapped atoms in collective strong coupling regime with the cavity leads to lasing at a frequency red detuned from the atomic transition. Lasing is demonstrated experimentally by the observation of a lasing threshold accompanied by polarization and spatial mode purity, and line-narrowing in the outcoupled light. Spontaneous emission into the cavity mode by the driven atoms stimulates lasing action, which is capable of operating as a continuous wave laser in steady state, without a seed laser. The system is modeled theoretically, and qualitative agreement with experimentally observed lasing is seen. Our result opens up a range of new measurement possibilities with this system.

Corrosion behavior of high purity Fe-Cr-Ni alloys in trans-passive condition

International Nuclear Information System (INIS)

Mayuzumi, Masami; Ohta, Jyoji; Kako, Kenji

1998-01-01

The corrosion behavior of high-purity (99.99%) Fe-Cr-Ni alloys was investigated in 13 N nitric acid with/without Ce 4+ ions to clarify the effect of impurities on the trans-passive corrosion of stainless steel. The following results were obtained. (1) Almost no intergranular corrosion was observed in the high-purity alloys, although the corrosion rate of the matrix region was nearly the same as that of a commercial stainless steel with the same Cr and Ni content. (2) Due to the improved intergranular corrosion resistance, the effect of the purification became significant in the corrosion condition with the grain-separation being predominant. (3) The high-purity alloys showed higher susceptivility to intergranular corrosion with aging treatment between 873 K and 1073 K. Although the sulfuric acid/copper sulfate test suggested the formation of Cr-depleted zones, a grain boundary micro-analysis using a FETEM with an EDX did not reveal any change in Cr content or impurity segregain along the grain boundaries. The mechanism of corrosion enhancement resulting from the aging treatment remains nuclear. (author)

Chemical purity using quantitative "1H-nuclear magnetic resonance: a hierarchical Bayesian approach for traceable calibrations

International Nuclear Information System (INIS)

Toman, Blaza; Nelson, Michael A.; Lippa, Katrice A.

2016-01-01

Chemical purity assessment using quantitative "1H-nuclear magnetic resonance spectroscopy is a method based on ratio references of mass and signal intensity of the analyte species to that of chemical standards of known purity. As such, it is an example of a calculation using a known measurement equation with multiple inputs. Though multiple samples are often analyzed during purity evaluations in order to assess measurement repeatability, the uncertainty evaluation must also account for contributions from inputs to the measurement equation. Furthermore, there may be other uncertainty components inherent in the experimental design, such as independent implementation of multiple calibration standards. As such, the uncertainty evaluation is not purely bottom up (based on the measurement equation) or top down (based on the experimental design), but inherently contains elements of both. This hybrid form of uncertainty analysis is readily implemented with Bayesian statistical analysis. In this article we describe this type of analysis in detail and illustrate it using data from an evaluation of chemical purity and its uncertainty for a folic acid material. (authors)

High purity hydrogen production system by the PSA method

Energy Technology Data Exchange (ETDEWEB)

1986-01-01

In a process developed by Nippon Steel, coke oven gas is compressed and purified of tarry matter, sulphur compounds and gum-formers by adsorption. It is then passed through a three-tower pressure-swing adsorption system to recover hydrogen whose purity can be selected in the range 99 to 99.999%. A composite adsorption agent is used.

Tunable Microcavity-Stabilized Quantum Cascade Laser for Mid-IR High-Resolution Spectroscopy and Sensing.

Science.gov (United States)

Borri, Simone; Siciliani de Cumis, Mario; Insero, Giacomo; Bartalini, Saverio; Cancio Pastor, Pablo; Mazzotti, Davide; Galli, Iacopo; Giusfredi, Giovanni; Santambrogio, Gabriele; Savchenkov, Anatoliy; Eliyahu, Danny; Ilchenko, Vladimir; Akikusa, Naota; Matsko, Andrey; Maleki, Lute; De Natale, Paolo

2016-02-17

The need for highly performing and stable methods for mid-IR molecular sensing and metrology pushes towards the development of more and more compact and robust systems. Among the innovative solutions aimed at answering the need for stable mid-IR references are crystalline microresonators, which have recently shown excellent capabilities for frequency stabilization and linewidth narrowing of quantum cascade lasers with compact setups. In this work, we report on the first system for mid-IR high-resolution spectroscopy based on a quantum cascade laser locked to a CaF₂ microresonator. Electronic locking narrows the laser linewidth by one order of magnitude and guarantees good stability over long timescales, allowing, at the same time, an easy way for finely tuning the laser frequency over the molecular absorption line. Improvements in terms of resolution and frequency stability of the source are demonstrated by direct sub-Doppler recording of a molecular line.

Characterization of a high-purity germanium detector for small-animal SPECT.

Science.gov (United States)

Johnson, Lindsay C; Campbell, Desmond L; Hull, Ethan L; Peterson, Todd E

2011-09-21

We present an initial evaluation of a mechanically cooled, high-purity germanium double-sided strip detector as a potential gamma camera for small-animal SPECT. It is 90 mm in diameter and 10 mm thick with two sets of 16 orthogonal strips that have a 4.5 mm width with a 5 mm pitch. We found an energy resolution of 0.96% at 140 keV, an intrinsic efficiency of 43.3% at 122 keV and a FWHM spatial resolution of approximately 1.5 mm. We demonstrated depth-of-interaction estimation capability through comparison of pinhole acquisitions with a point source on and off axes. Finally, a flood-corrected flood image exhibited a strip-level uniformity of less than 1%. This high-purity germanium offers many desirable properties for small-animal SPECT.

Temperature dependence of the ESR linewidth in the paramagnetic phase (T>TC) of R1-xBxMnO3+δ (R=La,Pr; B=Ca,Sr)

International Nuclear Information System (INIS)

Rettori, C.; Rao, D.; Singley, J.; Kidwell, D.; Oseroff, S.B.; Causa, M.T.; Neumeier, J.J.; McClellan, K.J.; Cheong, S.; Schultz, S.

1997-01-01

Electron spin resonance (ESR) experiments in the paramagnetic phase of R 1-x B x MnO 3+δ (R=La,Pr; B=Ca,Sr) show, for 1.1 T C approx-lt T approx-lt 2T C , a linear T increase of the resonance linewidth, ΔH, in powders, ceramic pellets, and single crystals. Above ∼2T C a slowdown in the T increase of ΔH is observed. The data resemble the results found in other ferromagnetic insulators where the spin-lattice relaxation involves a single-phonon process. We find that the one-phonon process may account for the linear T dependence of the linewidth observed up to ∼2T C . A large T dependence of the resonance intensity above T C was found in all the samples studied, suggesting the existence of spin clusters in these compounds over a wide range of temperature. copyright 1997 The American Physical Society

Kit preparation of 153Sm-EDTMP and factors affecting radiochemical purity and stability

International Nuclear Information System (INIS)

Ferro-Flores, G.; Tendilla, J.I.; Lopez-Gomez, M.A.; Aguilar-Hernandez, F.; Gonzalez-Zavala, M.A.; Parades-Gutierrez, L.; Avila-Ramirez, E.

1996-01-01

A fast kit method was developed for the production of 153 Sm-EDTMP in two steps avoiding the use of nitric acid, evaporation and sterilization of the final solution by autoclave. Methods of analysis for the determination of chemical and radiochemical purity in the radiopharmaceutical solution were established. Factors affecting radiochemical purity and stability of the complex as the molar ratio of EDTMP/Sm, concentration of phosphate buffer and neutralization of EDTMP prior kit preparation were also analyzed. The use of this radiopharmaceutical in rabbits and patients showed selective skeletal uptake. (author). 5 refs., 4 figs., 3 tabs

Preparation of high-purity zirconium dioxide from baddeleyite

International Nuclear Information System (INIS)

Voskobojnikov, N.B.; Skiba, G.S.

1996-01-01

Interaction of baddeleyite concentrate with calcium oxide and calcium chloride in the process of caking is studied. The influence of grain size on calcium zirconate formation is tested. Conditions for cake leaching by hydrochloric acid and zirconium(4) oxychloride purification from calcium and silicon compounds by recrystallization are reported. Zirconium dioxide corresponding to specifications (6-2 special purity) is obtained with a high (more than 90%) chemical yield. 9 refs., 1 tab

Wet routes of high purity BaTiO3 nanopowders

International Nuclear Information System (INIS)

Wang Liqiu; Liu Liang; Xue Dongfeng; Kang Hongmin; Liu Changhou

2007-01-01

High purity BaTiO 3 nanopowders were prepared in wet routes through stearic acid gel (SAG) and acetic acid gel (AAG) techniques, respectively. BaTiO 3 samples were characterized by X-ray diffraction, transmission electron microscope, Fourier transform infrared spectrometry, X-ray fluorescence spectrometry, and thermal gravimetric analysis. The present results indicate that both methods have a similar reaction process during calcination, while BaTiO 3 crystallites were initially formed at 550 deg. C by SAG and 800 deg. C by AAG. Both methods could produce BaTiO 3 powders with a cubic perovskite structure, while they had different grain size distributions within 25-50 nm for SAG and 50-80 nm for AAG. BaTiO 3 samples prepared by SAG had a lower agglomeration than those by AAG. SAG has shown many distinctive advantages in the preparation of high purity BaTiO 3 nanopowders, without Ba and Ti losses and hazardous wastes

Development of high purity large forgings for nuclear power plants

International Nuclear Information System (INIS)

Tanaka, Yasuhiko; Sato, Ikuo

2011-01-01

The recent increase in the size of energy plants has been supported by the development of manufacturing technology for high purity large forgings for the key components of the plant. To assure the reliability and performance of the large forgings, refining technology to make high purity steels, casting technology for gigantic ingots, forging technology to homogenize the material and consolidate porosity are essential, together with the required heat treatment and machining technologies. To meet these needs, the double degassing method to reduce impurities, multi-pouring methods to cast the gigantic ingots, vacuum carbon deoxidization, the warm forging process and related technologies have been developed and further improved. Furthermore, melting facilities including vacuum induction melting and electro slag re-melting furnaces have been installed. By using these technologies and equipment, large forgings have been manufactured and shipped to customers. These technologies have also been applied to the manufacture of austenitic steel vessel components of the fast breeder reactors and components for fusion experiments.

Development of high purity large forgings for nuclear power plants

Science.gov (United States)

Tanaka, Yasuhiko; Sato, Ikuo

2011-10-01

The recent increase in the size of energy plants has been supported by the development of manufacturing technology for high purity large forgings for the key components of the plant. To assure the reliability and performance of the large forgings, refining technology to make high purity steels, casting technology for gigantic ingots, forging technology to homogenize the material and consolidate porosity are essential, together with the required heat treatment and machining technologies. To meet these needs, the double degassing method to reduce impurities, multi-pouring methods to cast the gigantic ingots, vacuum carbon deoxidization, the warm forging process and related technologies have been developed and further improved. Furthermore, melting facilities including vacuum induction melting and electro slag re-melting furnaces have been installed. By using these technologies and equipment, large forgings have been manufactured and shipped to customers. These technologies have also been applied to the manufacture of austenitic steel vessel components of the fast breeder reactors and components for fusion experiments.

Gravimetric and volumetric determination of the purity of electrolytically refined silver and the produced silver nitrate

Directory of Open Access Journals (Sweden)

Ačanski Marijana M.

2007-01-01

Full Text Available Silver is, along with gold and the platinum-group metals, one of the so called precious metals. Because of its comparative scarcity, brilliant white color, malleability and resistance to atmospheric oxidation, silver has been used in the manufacture of coins and jewelry for a long time. Silver has the highest known electrical and thermal conductivity of all metals and is used in fabricating printed electrical circuits, and also as a coating for electronic conductors. It is also alloyed with other elements such as nickel or palladium for use in electrical contacts. The most useful silver salt is silver nitrate, a caustic chemical reagent, significant as an antiseptic and as a reagent in analytical chemistry. Pure silver nitrate is an intermediate in the industrial preparation of other silver salts, including the colloidal silver compounds used in medicine and the silver halides incorporated into photographic emulsions. Silver halides become increasingly insoluble in the series: AgCl, AgBr, AgI. All silver salts are sensitive to light and are used in photographic coatings on film and paper. The ZORKA-PHARMA company (Sabac, Serbia specializes in the production of pharmaceutical remedies and lab chemicals. One of its products is chemical silver nitrate (argentum-nitricum (l. Silver nitrate is generally produced by dissolving pure electrolytically refined silver in hot 48% nitric acid. Since the purity of silver nitrate, produced in 2002, was not in compliance with the p.a. level of purity, there was doubt that the electrolytically refined silver was pure. The aim of this research was the gravimetric and volumetric determination of the purity of electrolytically refined silver and silver nitrate, produced industrially and in a laboratory. The purity determination was carried out gravimetrically, by the sedimentation of silver(I ions in the form of insoluble silver salts: AgCl, AgBr and Agi, and volumetrically, according to Mohr and Volhardt. The

Spectrally narrow, long-term stable optical frequency reference based on a Eu3+:Y2SiO5 crystal at cryogenic temperature.

Science.gov (United States)

Chen, Qun-Feng; Troshyn, Andrei; Ernsting, Ingo; Kayser, Steffen; Vasilyev, Sergey; Nevsky, Alexander; Schiller, Stephan

2011-11-25

Using an ultrastable continuous-wave laser at 580 nm we performed spectral hole burning of Eu(3+):Y(2)SiO(5) at a very high spectral resolution. The essential parameters determining the usefulness as a macroscopic frequency reference, linewidth, temperature sensitivity, and long-term stability, were characterized using a H-maser stabilized frequency comb. Spectral holes with a linewidth as low as 6 kHz were observed and the upper limit of the drift of the hole frequency was determined to be 5±3 mHz/s. We discuss the necessary requirements for achieving ultrahigh stability in laser frequency stabilization to these spectral holes.

Creating high-purity angular-momentum-state Rydberg atoms by a pair of unipolar laser pulses

Science.gov (United States)

Xin, PeiPei; Cheng, Hong; Zhang, ShanShan; Wang, HanMu; Xu, ZiShan; Liu, HongPing

2018-04-01

We propose a method of producing high-purity angular-momentum-state Rydberg atoms by a pair of unipolar laser pulses. The first positive-polarity optical half-cycle pulse is used to prepare an excited-state wave packet while the second one is less intense, but with opposite polarity and time delayed, and is employed to drag back the escaping free electron and clip the shape of the bound Rydberg wave packet, selectively increasing or decreasing a fraction of the angular-momentum components. An intelligent choice of laser parameters such as phase and amplitude helps us to control the orbital-angular-momentum composition of an electron wave packet with more facility; thus, a specified angular-momentum state with high purity can be achieved. This scheme of producing high-purity angular-momentum-state Rydberg atoms has significant application in quantum-information processing.

High Power Narrow Linewidth 1.26 Micron Ho-Doped Fiber Amplifier, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — This proposal is for the development of an innovative, high power, and extremely reliable 1.26-micron Ho-doped fluoride fiber amplifier. The proposed fiber amplifier...

High Power Narrow Linewidth 1.26 Micron Ho-Doped Fiber Amplifier, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This proposal is for the development of an innovative, high power, and extremely reliable 1.26-micron Ho-doped fluoride fiber amplifier. The proposed fiber amplifier...

N-Type delta Doping of High-Purity Silicon Imaging Arrays

Science.gov (United States)

Blacksberg, Jordana; Hoenk, Michael; Nikzad, Shouleh

2005-01-01

A process for n-type (electron-donor) delta doping has shown promise as a means of modifying back-illuminated image detectors made from n-doped high-purity silicon to enable them to detect high-energy photons (ultraviolet and x-rays) and low-energy charged particles (electrons and ions). This process is applicable to imaging detectors of several types, including charge-coupled devices, hybrid devices, and complementary metal oxide/semiconductor detector arrays. Delta doping is so named because its density-vs.-depth characteristic is reminiscent of the Dirac delta function (impulse function): the dopant is highly concentrated in a very thin layer. Preferably, the dopant is concentrated in one or at most two atomic layers in a crystal plane and, therefore, delta doping is also known as atomic-plane doping. The use of doping to enable detection of high-energy photons and low-energy particles was reported in several prior NASA Tech Briefs articles. As described in more detail in those articles, the main benefit afforded by delta doping of a back-illuminated silicon detector is to eliminate a "dead" layer at the back surface of the silicon wherein high-energy photons and low-energy particles are absorbed without detection. An additional benefit is that the delta-doped layer can serve as a back-side electrical contact. Delta doping of p-type silicon detectors is well established. The development of the present process addresses concerns specific to the delta doping of high-purity silicon detectors, which are typically n-type. The present process involves relatively low temperatures, is fully compatible with other processes used to fabricate the detectors, and does not entail interruption of those processes. Indeed, this process can be the last stage in the fabrication of an imaging detector that has, in all other respects, already been fully processed, including metallized. This process includes molecular-beam epitaxy (MBE) for deposition of three layers, including

Purity of potassium iodide necessary for its use in phasers

Energy Technology Data Exchange (ETDEWEB)

Sood, B R [Punjabi Univ., Patiala (India). Dept. of Physics

1981-08-16

The purity requirements in KI crystals are discussed necessary to have longer lifetimes of phonons for its use in phasers. The main contribution to the phonon scattering at low temperatures arises from the scattering by natural isotopes (/sup 39/K, /sup 40/K, /sup 41/K, /sup 127/I).

Improved methods to determine radionuclidic purity of F-18 compounds

DEFF Research Database (Denmark)

Jørgensen, Thomas; Micheelsen, Mille Ankerstjerne; Jensen, Mikael

2012-01-01

Current revisions of monographs for F-18 pharmaceuticals in the European Pharmacopoeia (Ph. Eur.) (Ph. Eur., 2011) call for a radionuclidic purity (RNP) of or better than 99.9%. However, the current method is not sufficient nor effective for testing this required RNP level. We present a theoretical...

Ocular Biometrics of Myopic Eyes With Narrow Angles.

Science.gov (United States)

Chong, Gabriel T; Wen, Joanne C; Su, Daniel Hsien-Wen; Stinnett, Sandra; Asrani, Sanjay

2016-02-01

The purpose of this study was to compare the ocular biometrics between myopic patients with and without narrow angles. Patients with a stable myopic refraction (myopia worse than -1.00 D spherical equivalent) were prospectively recruited. Angle status was assessed using gonioscopy and biometric measurements were performed using an anterior segment optical coherence tomography and an IOLMaster. A total of 29 patients (58 eyes) were enrolled with 13 patients (26 eyes) classified as having narrow angles and 16 patients (32 eyes) classified as having open angles. Baseline demographics of age, sex, and ethnicity did not differ significantly between the 2 groups. The patients with narrow angles were on average older than those with open angles but the difference did not reach statistical significance (P=0.12). The central anterior chamber depth was significantly less in the eyes with narrow angles (P=0.05). However, the average lens thickness, although greater in the eyes with narrow angles, did not reach statistical significance (P=0.10). Refractive error, axial lengths, and iris thicknesses did not differ significantly between the 2 groups (P=0.32, 0.47, 0.15). Narrow angles can occur in myopic eyes. Routine gonioscopy is therefore recommended for all patients regardless of refractive error.

Intramyocardial arterial narrowing in dogs with subaortic stenosis.

Science.gov (United States)

Falk, T; Jönsson, L; Pedersen, H D

2004-09-01

Earlier studies have described intramyocardial arterial narrowing based on hyperplasia and hypertrophy of the vessel wall in dogs with subaortic stenosis (SAS). In theory, such changes might increase the risk of sudden death, as they seem to do in heart disease in other species. This retrospective pathological study describes and quantifies intramyocardial arterial narrowing in 44 dogs with naturally occurring SAS and in eight control dogs. The majority of the dogs with SAS died suddenly (n=27); nine had died or been euthanased with signs of heart failure and eight were euthanased without clinical signs. Dogs with SAS had significantly narrower intramyocardial arteries (Pdogs. Male dogs and those with more severe hypertrophy had more vessel narrowing (P=0.02 and P=0.02, respectively), whereas dogs with dilated hearts had slightly less pronounced arterial thickening (P=0.01). Arterial narrowing was not related to age, but fibrosis increased with age (P=0.047). Dogs that died suddenly did not have a greater number of arterial changes than other dogs with SAS. This study suggests that most dogs with SAS have intramyocardial arterial narrowing and that the risk of dying suddenly is not significantly related to the overall degree of vessel obliteration.

The European Expression Of Interest For High Purity U-233 Materials

Energy Technology Data Exchange (ETDEWEB)

Giaquinto, Joseph M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Younkin, James R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-04-01

The purpose of this letter report is to document the response for an Expression of Interest (EOI) sent to the European Safeguards and research and development (R&D) scientific communities for the distribution of small amounts of high purity ²³³U materials for use in safeguards, nonproliferation, and basic R&D in the nuclear disciplines. The intent for the EOI was to gauge the level of international interest for these materials from government and research institutions with programmatic missions in the nuclear security or nuclear R&D arena. The information contained herein is intended to provide information to assist key decision makers in DOE as to the ultimate disposition path for the high purity materials currently being recovered at Oak Ridge National Laboratory (ORNL) and only those items for which there is no United States (U.S.) sponsor identified.

Highly Tunable Narrow Bandpass MEMS Filter

KAUST Repository

Hafiz, Md Abdullah Al

2017-07-07

We demonstrate a proof-of-concept highly tunable narrow bandpass filter based on electrothermally and electrostatically actuated microelectromechanical-system (MEMS) resonators. The device consists of two mechanically uncoupled clamped-clamped arch resonators, designed such that their resonance frequencies are independently tuned to obtain the desired narrow passband. Through the electrothermal and electrostatic actuation, the stiffness of the structures is highly tunable. We experimentally demonstrate significant percentage tuning (~125%) of the filter center frequency by varying the applied electrothermal voltages to the resonating structures, while maintaining a narrow passband of 550 ± 50 Hz, a stopband rejection of >17 dB, and a passband ripple ≤ 2.5 dB. An analytical model based on the Euler-Bernoulli beam theory is used to confirm the behavior of the filter, and the origin of the high tunability using electrothermal actuation is discussed.

Simulation of inverse Compton scattering and its implications on the scattered linewidth

Science.gov (United States)

Ranjan, N.; Terzić, B.; Krafft, G. A.; Petrillo, V.; Drebot, I.; Serafini, L.

2018-03-01

Rising interest in inverse Compton sources has increased the need for efficient models that properly quantify the behavior of scattered radiation given a set of interaction parameters. The current state-of-the-art simulations rely on Monte Carlo-based methods, which, while properly expressing scattering behavior in high-probability regions of the produced spectra, may not correctly simulate such behavior in low-probability regions (e.g. tails of spectra). Moreover, sampling may take an inordinate amount of time for the desired accuracy to be achieved. In this paper, we present an analytic derivation of the expression describing the scattered radiation linewidth and propose a model to describe the effects of horizontal and vertical emittance on the properties of the scattered radiation. We also present an improved version of the code initially reported in Krafft et al. [Phys. Rev. Accel. Beams 19, 121302 (2016), 10.1103/PhysRevAccelBeams.19.121302], that can perform the same simulations as those present in cain and give accurate results in low-probability regions by integrating over the emissions of the electrons. Finally, we use these codes to carry out simulations that closely verify the behavior predicted by the analytically derived scaling law.

Influence of moisture and hydrogen purity of the reliability of powerful electric machines

International Nuclear Information System (INIS)

Vigovs'kij, O.V.; Khvalyin, D.Yi.; Mistets'kij, V.A.

2017-01-01

It is shown that today the turbo generators with hydrogen-water cooling system is most unreliable technical equipment of Ukrainian nuclear power plants. On the one hand, hydrogen has several advantages over other coolers; on the other hand, the presence of hydrogen in the turbo generators systems carries the danger of engine rooms of power plants. It is also shown that the water and oxygen are main hazardous impurities in hydrogen, and zone of generator shaft compaction is the most responsible zone with high concentration of water. From the analysis was found that increasing of hydrogen purity reduces the mechanical losses and the change in total losses depending on the hydrogen purity has a linear nature. For example, with an increase the hydrogen purity from 0,1203 to 0,09 the loss in turbo generator rotor can be reduced by nearly 500 kW, which is about 25 % at a pressure of 0,5 MPa. The possibility of using metal hydrides to ensure purity, purification and hydrogen sorption was looked. The most practical value is for such hydrides as LaNi5Hx, FeTiHx, ZrNiHx. The main advantage the metal hydrides method of purification is a significant reduction in the number of purification stages. It was shown that the use of a thermoelectric gas dryer will reduce the total consumption of technological gases, that are removed from nuclear power plants, by 2,3 - 2,4 times due to a decrease in 5,0 - 6,0 times their absolute humidity, and decrease by 5, 0 times the activity of gases due to an increase in their exposure time in the decrease activity installation. All this suggests that the creation a hydrogen humidity monitoring system in the exploited turbo generator will solve the problem of objective control of hydrogen purity with further computerization and accumulation the information. Using a drainage or purification system of hydrogen, reducing the temperature and humidity of the cooling gas, can increase the reliability of operation the turbo generators and significantly

An ICP AES method for determination of dysprosium and terbium in high purity yttrium oxide

International Nuclear Information System (INIS)

Rupawate, V.H.; Hareendran, K.N.; Roy, S.B.

2011-01-01

High purity yttrium finds interesting application in astronavigation, luminescence, nuclear energy and metallurgical industries. Most of these applications require yttrium oxide of highest purity. Consequently there is a need for production of high purity yttrium oxide. Separation and purification of yttrium from other rare earths is a challenging task due to their close chemical properties. Liquid-liquid extraction and ion exchange have been widely used in the production of yttrium oxide of highest purity. Determination of impurities, especially other rare earths, in ppm level is required for process development and chemical characterization of the high purity Y 2 O 3 . Many methods have been described in literature. However since the advent of ICP AES much work in this area has been carried out by this technique. This paper describes the work done for determination of dysprosium (Dy) and terbium (Tb) in yttrium oxide using a high resolution sequential ICP AES. Emission spectra of rare earth elements are very complex and due to this complexity it is important to select spectral interference free analyte lines for determination of rare earths in rare earth matrix. For the determination of Dy and Tb in Y 2 O 3 , sensitive lines of Dy and Tb are selected from the instrument wavelength table and spectral interference free emission lines for the determination is selected by scanning around the selected wavelengths using 5 g/L Y solution and 5 mg/L standard solutions of Dy and Tb prepared in 4% nitric acid. It is found 353.170 nm line of Dy and 350.917 nm line Tb is suitable for quantitative determination. The signal to background ratio increases with increase in matrix concentration, i.e. from 1 to 5 mg/L. The optimum forward power is determined and it is found to be 1100W for Dy and 1000W for Tb. The instrument is calibrated using matrix matched standards containing 5g/L of Y matrix. Samples are dissolved in nitric acid and Y concentration is maintained at 5g/L. Two

Spin polarization of {sup 87}Rb atoms with ultranarrow linewidth diode laser: Numerical simulation

Energy Technology Data Exchange (ETDEWEB)

Wang, Z. G. [College of OptoElectronic Science and Engineering, National University of Defense Technology, Changsha, 410073 (China); Interdisciplinary Center of Quantum Information, National University of Defense Technology, Changsha, 410073 (China); College of Science, National University of Defense Technology, Changsha, 410073 (China); Jiang, Q. Y.; Zhan, X.; Chen, Y. D.; Luo, H., E-mail: luohui.luo@163.com [College of OptoElectronic Science and Engineering, National University of Defense Technology, Changsha, 410073 (China); Interdisciplinary Center of Quantum Information, National University of Defense Technology, Changsha, 410073 (China)

2016-08-15

In order to polarize {sup 87}Rb vapor effectively with ultranarrow linewidth diode laser, we studied the polarization as a function of some parameters including buffer gas pressure and laser power. Moreover, we also discussed the methods which split or modulate the diode laser frequency so as to pump the two ground hyperfine levels efficiently. We obtained some useful results through numerical simulation. If the buffer gas pressure is so high that the hyperfine structure is unresolved, the polarization is insensitive to laser frequency at peak absorption point so frequency splitting and frequency modulation methods do not show improvement. At low pressure and laser power large enough, where the hyperfine structure is clearly resolved, frequency splitting and frequency modulation methods can increase polarization effectively. For laser diodes, frequency modulation is easily realized with current modulation, so this method is attractive since it does not add any other components in the pumping laser system.

Characterization of Cs vapor cell coated with octadecyltrichlorosilane using coherent population trapping spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Hafiz, Moustafa Abdel; Maurice, Vincent; Chutani, Ravinder; Passilly, Nicolas; Gorecki, Christophe; Boudot, Rodolphe [FEMTO-ST, CNRS, UFC, 26 Chemin de l' Epitaphe, 25030 Besançon Cedex (France); Guérandel, Stéphane; Clercq, Emeric de [LNE-SYRTE, Observatoire de Paris, CNRS, UPMC, 61 avenue de l' Observatoire, 75014 Paris (France)

2015-05-14

We report the realization and characterization using coherent population trapping (CPT) spectroscopy of an octadecyltrichlorosilane (OTS)-coated centimeter-scale Cs vapor cell. The dual-structure of the resonance lineshape, with presence of a narrow structure line at the top of a Doppler-broadened structure, is clearly observed. The linewidth of the narrow resonance is compared to the linewidth of an evacuated Cs cell and of a buffer gas Cs cell of similar size. The Cs-OTS adsorption energy is measured to be (0.42 ± 0.03) eV, leading to a clock frequency shift rate of 2.7 × 10{sup −9}/K in fractional unit. A hyperfine population lifetime, T{sub 1}, and a microwave coherence lifetime, T{sub 2}, of 1.6 and 0.5 ms are reported, corresponding to about 37 and 12 useful bounces, respectively. Atomic-motion induced Ramsey narrowing of dark resonances is observed in Cs-OTS cells by reducing the optical beam diameter. Ramsey CPT fringes are detected using a pulsed CPT interrogation scheme. Potential applications of the Cs-OTS cell to the development of a vapor cell atomic clock are discussed.

Characterization of Cs vapor cell coated with octadecyltrichlorosilane using coherent population trapping spectroscopy

International Nuclear Information System (INIS)

Hafiz, Moustafa Abdel; Maurice, Vincent; Chutani, Ravinder; Passilly, Nicolas; Gorecki, Christophe; Boudot, Rodolphe; Guérandel, Stéphane; Clercq, Emeric de

2015-01-01

We report the realization and characterization using coherent population trapping (CPT) spectroscopy of an octadecyltrichlorosilane (OTS)-coated centimeter-scale Cs vapor cell. The dual-structure of the resonance lineshape, with presence of a narrow structure line at the top of a Doppler-broadened structure, is clearly observed. The linewidth of the narrow resonance is compared to the linewidth of an evacuated Cs cell and of a buffer gas Cs cell of similar size. The Cs-OTS adsorption energy is measured to be (0.42 ± 0.03) eV, leading to a clock frequency shift rate of 2.7 × 10 −9 /K in fractional unit. A hyperfine population lifetime, T 1 , and a microwave coherence lifetime, T 2 , of 1.6 and 0.5 ms are reported, corresponding to about 37 and 12 useful bounces, respectively. Atomic-motion induced Ramsey narrowing of dark resonances is observed in Cs-OTS cells by reducing the optical beam diameter. Ramsey CPT fringes are detected using a pulsed CPT interrogation scheme. Potential applications of the Cs-OTS cell to the development of a vapor cell atomic clock are discussed

The investigation of ferromagnetic resonance linewidth in Ni80Fe20 films with submicron rectangular elements

Directory of Open Access Journals (Sweden)

D. Zhang

2016-05-01

Full Text Available Patterned magnetic films with nano-scaled dots exhibit some special magnetic properties. In this paper, we investigate the in-plane shape anisotropy and the magnetization dynamic damping in permalloy (Ni80Fe20 arrays of submicron rectangular elements using ferromagnetic resonance (FMR. The FMR linewidth exhibits a dependence on the element size, and mainly comes from the contribution of the intrinsic damping. Also the contribution of two-magnon scattering plays an important role and is reduced with increasing aspect ratio. The damping coefficient decreases from 0.0129 to 0.0118 with the element length increasing from 300 nm to 1200 nm, and the theoretical calculation suggests that the change of damping results from the longitudinal and transverse interlayer spin current due to the spatially inhomogeneous magnetization dynamics.

Preparation of uranium-plutonium mixed nitride pellets with high purity

International Nuclear Information System (INIS)

Arai, Yasuo; Shiozawa, Ken-ichi; Ohmichi, Toshihiko

1992-01-01

Uranium-plutonium mixed nitride pellets have been prepared in the gloveboxes with high purity Ar gas atmosphere. Carbothermic reduction of the oxides in N 2 -H 2 mixed gas stream was adopted for synthesizing mixed nitride. Sintering was carried out in various conditions and the effect on the pellet characteristics was investigated. (author)

Dose evaluation of narrow-beam

International Nuclear Information System (INIS)

Goto, Shinichi

1999-01-01

Reliability of the dose from the narrow photon beam becomes more important since the single high-dose rate radiosurgery becoming popular. The dose evaluation for the optimal dose is difficult due to absence of lateral electronic equilibrium. Data necessary for treatment regimen are TMR (tissue maximum ratio), OCR (off center ratio) and S c,p (total scatter factor). The narrow-beam was 10 MV X-ray from Varian Clinac 2100C equipped with cylindrical Fischer collimator CBI system. Detection was performed by Kodak XV-2 film, a PTW natural diamond detector M60003, Scanditronics silicon detector EDD-5 or Fujitec micro-chamber FDC-9.4C. Phantoms were the water equivalent one (PTW, RW3), water one (PTW, MP3 system) and Wellhofer WP600 system. Factors above were actually measured to reveal that in the dose evaluation of narrow photon beam, TMR should be measured by micro-chamber, OCR, by film, and S c,p , by the two. The use of diamond detector was recommended for more precise measurement and evaluation of the dose. The importance of water phantom in the radiosurgery system was also shown. (K.H.)

Comparison of different thin layer detection techniques to determine the radiochemical purity of radiopharmaceuticals

International Nuclear Information System (INIS)

Hammermaier, A.; Reich, E.; Boegl, W.

1985-01-01

Ten radiopharmaceuticals frequently used in clinical treatment were examined as to their radiochemical purity by paper and thin layer chromatography or electrophoresis, respectively. It is known that radiochemical impurities may result in an unnecessary exposure of the patients to be examined. Other than determining the radiochemical purity of several radiopharmaceuticals, a comparison of the different measuring methods of distributing activity on radiochromatograms or electropherograms is intended by this study. For this, the activity distribution in the developed radiochromatograms was assessed by four different measuring methods (TLC-linear analyzer, TLC-scanner with NaI(Tl) detector, TLC-scanner with gas flow counter and NaI(Tl) well-typ counter). As shown by the above analysis, only the TLC-linear analyzer and the NaI(Tl) well-typ counter (measurement of chromatograms or electropherograms cut into strips) are generally suitable methods for determining the radiochemical purity of radiochemicals, the TLC-scanner with gas flow counter is usable in most cases, while TLC-scanner with NaI(Tl) detector is yielding unsatisfactory results. (orig.) [de

Effect of the microstructure on electrical properties of high-purity germanium

Science.gov (United States)

Podkopaev, O. I.; Shimanskii, A. F.; Molotkovskaya, N. O.; Kulakovskaya, T. V.

2013-05-01

The interrelation between the electrical properties and the microstructure of high-purity germanium crystals has been revealed. The electrical conductivity of polycrystalline samples increases and the life-time of nonequilibrium charge carriers in them decreases with a decrease in the crystallite sizes.

Stabilization of self-mode-locked quantum dash lasers by symmetric dual-loop optical feedback

Science.gov (United States)

Asghar, Haroon; Wei, Wei; Kumar, Pramod; Sooudi, Ehsan; McInerney, John. G.

2018-02-01

We report experimental studies of the influence of symmetric dual-loop optical feedback on the RF linewidth and timing jitter of self-mode-locked two-section quantum dash lasers emitting at 1550 nm. Various feedback schemes were investigated and optimum levels determined for narrowest RF linewidth and low timing jitter, for single-loop and symmetric dual-loop feedback. Two symmetric dual-loop configurations, with balanced and unbalanced feedback ratios, were studied. We demonstrate that unbalanced symmetric dual loop feedback, with the inner cavity resonant and fine delay tuning of the outer loop, gives narrowest RF linewidth and reduced timing jitter over a wide range of delay, unlike single and balanced symmetric dual-loop configurations. This configuration with feedback lengths 80 and 140 m narrows the RF linewidth by 4-67x and 10-100x, respectively, across the widest delay range, compared to free-running. For symmetric dual-loop feedback, the influence of different power split ratios through the feedback loops was determined. Our results show that symmetric dual-loop feedback is markedly more effective than single-loop feedback in reducing RF linewidth and timing jitter, and is much less sensitive to delay phase, making this technique ideal for applications where robustness and alignment tolerance are essential.

Magnetic resonance of rubidium atoms passing through a multi-layered transmission magnetic grating

International Nuclear Information System (INIS)

Nagata, Y; Kurokawa, S; Hatakeyama, A

2017-01-01

We measured the magnetic resonance of rubidium atoms passing through periodic magnetic fields generated by two types of multi-layered transmission magnetic grating. One of the gratings reported here was assembled by stacking four layers of magnetic films so that the direction of magnetization alternated at each level. The other grating was assembled so that the magnetization at each level was aligned. For both types of grating, the experimental results were in good agreement with our calculations. We studied the feasibility of extending the frequency band of the grating and narrowing its resonance linewidth by performing calculations. For magnetic resonance precision spectroscopy, we conclude that the multi-layered transmission magnetic grating can generate periodic fields with narrower linewidths at higher frequencies when a larger number of layers are assembled at a shorter period length. Moreover, the frequency band of this type of grating can potentially achieve frequencies of up to hundreds of PHz. (paper)

Tunable Microcavity-Stabilized Quantum Cascade Laser for Mid-IR High-Resolution Spectroscopy and Sensing

Directory of Open Access Journals (Sweden)

Simone Borri

2016-02-01

Full Text Available The need for highly performing and stable methods for mid-IR molecular sensing and metrology pushes towards the development of more and more compact and robust systems. Among the innovative solutions aimed at answering the need for stable mid-IR references are crystalline microresonators, which have recently shown excellent capabilities for frequency stabilization and linewidth narrowing of quantum cascade lasers with compact setups. In this work, we report on the first system for mid-IR high-resolution spectroscopy based on a quantum cascade laser locked to a CaF2 microresonator. Electronic locking narrows the laser linewidth by one order of magnitude and guarantees good stability over long timescales, allowing, at the same time, an easy way for finely tuning the laser frequency over the molecular absorption line. Improvements in terms of resolution and frequency stability of the source are demonstrated by direct sub-Doppler recording of a molecular line.

Weak-field precession of nano-pillar spin-torque oscillators using MgO-based perpendicular magnetic tunnel junction

Science.gov (United States)

Zhang, Changxin; Fang, Bin; Wang, Bochong; Zeng, Zhongming

2018-04-01

This paper presents a steady auto-oscillation in a spin-torque oscillator using MgO-based magnetic tunnel junction (MTJ) with a perpendicular polarizer and a perpendicular free layer. As the injected d.c. current varied from 1.5 to 3.0 mA under a weak magnetic field of 290 Oe, the oscillation frequency decreased from 1.85 to 1.3 GHz, and the integrated power increased from 0.1 to 74 pW. A narrow linewidth down to 7 MHz corresponding to a high Q factor of 220 was achieved at 2.7 mA, which was ascribed to the spatial coherent procession of the free layer magnetization. Moreover, the oscillation frequency was quite sensitive to the applied field, about 3.07 MHz/Oe, indicating the potential applications as a weak magnetic field detector. These results suggested that the MgO-based MTJ with perpendicular magnetic easy axis could be helpful for developing spin-torque oscillators with narrow-linewidth and high sensitive.

Some aspects of ICP-AES analysis of high purity rare earths

International Nuclear Information System (INIS)

Murty, P.S.; Biswas, S.S.

1991-01-01

Inductively coupled plasma atomic emission spectrometry (ICP-AES) is a technique capable of giving high sensitivity in trace elemental analysis. While the technique possesses high sensitivity, it lacks high selectivity. Selectivity is important where substances emitting complex spectra are to be analysed for trace elements. Rare earths emit highly complex spectra in a plasma source and the determination of adjacent rare earths in a high purity rare earth matrix, with high sensitivity, is not possible due to the inadequate selectivity of ICP-AES. One approach that has yielded reasonably good spectral selectivity in the high purity rare earth analysis by ICP-AES is by employing a combination of wavelength modulation techniques and high resolution echelle grating. However, it was found that by using a high resolution monochromator senstitivities either comparable to or better than those reported by the wavelength modulation technique could be obtained. (author). 2 refs., 2 figs., 2 tabs

Construction, assembling and operation of an equipment for sodium purity

International Nuclear Information System (INIS)

Becquart, E.T.; Botbol, J.; Echenique, P.N.; Fruchtenicht, F.W.; Gil, D.A.; Perillo, P.; Vardich, R.N.; Vigo, D.E.

1993-01-01

The purpose of this work is the production of high purity metallic sodium for bench-scale, research studies. A stainless steel equipment was built and assembled, including high vacuum, heating and cooling systems. It was satisfactorily operated in two successive steps, filtration and vacuum distillation, with a good yield. (Author). 5 refs., 5 figs

Determination of radiochemistry purity and pH of radiopharmaceutical in Northeast nuclear medicine services

International Nuclear Information System (INIS)

Andrade, Wellington; Santos, Poliane; Lima, Fernando de Andrade; Lima, Fabiana Farias de

2013-01-01

The radiopharmaceutical is a chemical compound associated with a radionuclide, which is selected so that meets the need cf diagnosis and capable of producing quality images. Drugs labeled with 99m Tc radionuclide kits consist of lyophilized, and be handled by the nuclear medicine services (NMS) must pass tests as the resolution of ANVISA (RDC 38) published in 2008. Among these tests are those of radiochemical purity and pH determination. This study evaluated the radiochemical purity of radiopharmaceuticals and pH SMN manipulated in the Northeast. The radiochemical purity (RCP) was determined by thin layer chromatography, which were used Whatman ® and silica gel, with dimensions of 1 x 10 cm, as stationary phase, and solvents indicated in the inserts of manufacturers. The chromatographic strips were placed in sealed containers so as not to touch the walls thereof. After the chromatographic run, the tape was cut every centimeter and the activities determined in doses of each calibrator NMS. The pH of the radiopharmaceutical was assessed through the use of universal pH paper (Merck®) and obtained staining compared with its color scale. The results showed (hat 82.6% and 100% of the radiopharmaceuticals of the samples were within the limits recommended by international pharmacopoeias for radiochemical purity and pl-l, respectively. There is then the need to include in routine tests indicated SMN by ANVISA. Well, they can detect possible problems in the marking of radiopharmaceuticals administered to the patient and avoid inappropriate material. (author)

High-purity Cu nanocrystal synthesis by a dynamic decomposition method

Science.gov (United States)

Jian, Xian; Cao, Yu; Chen, Guozhang; Wang, Chao; Tang, Hui; Yin, Liangjun; Luan, Chunhong; Liang, Yinglin; Jiang, Jing; Wu, Sixin; Zeng, Qing; Wang, Fei; Zhang, Chengui

2014-12-01

Cu nanocrystals are applied extensively in several fields, particularly in the microelectron, sensor, and catalysis. The catalytic behavior of Cu nanocrystals depends mainly on the structure and particle size. In this work, formation of high-purity Cu nanocrystals is studied using a common chemical vapor deposition precursor of cupric tartrate. This process is investigated through a combined experimental and computational approach. The decomposition kinetics is researched via differential scanning calorimetry and thermogravimetric analysis using Flynn-Wall-Ozawa, Kissinger, and Starink methods. The growth was found to be influenced by the factors of reaction temperature, protective gas, and time. And microstructural and thermal characterizations were performed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and differential scanning calorimetry. Decomposition of cupric tartrate at different temperatures was simulated by density functional theory calculations under the generalized gradient approximation. High crystalline Cu nanocrystals without floccules were obtained from thermal decomposition of cupric tartrate at 271°C for 8 h under Ar. This general approach paves a way to controllable synthesis of Cu nanocrystals with high purity.

The effect of narrow provider networks on health care use.

Science.gov (United States)

Atwood, Alicia; Lo Sasso, Anthony T

2016-12-01

Network design is an often overlooked aspect of health insurance contracts. Recent policy factors have resulted in narrower provider networks. We provide plausibly causal evidence on the effect of narrow network plans offered by a large national health insurance carrier in a major metropolitan market. Our econometric design exploits the fact that some firms offer a narrow network plan to their employees and some do not. Our results show that narrow network health plans lead to reductions in health care utilization and spending. We find evidence that narrow networks save money by selecting lower cost providers into the network. Copyright © 2016 Elsevier B.V. All rights reserved.

High purity liquid phase epitaxial gallium arsenide nuclear radiation detector

International Nuclear Information System (INIS)

Alexiev, D.; Butcher, K.S.A.

1991-11-01

Surface barrier radiation detector made from high purity liquid phase epitaxial gallium arsenide wafers have been operated as X- and γ-ray detectors at various operating temperatures. Low energy isotopes are resolved including 241 Am at 40 deg C. and the higher gamma energies of 235 U at -80 deg C. 15 refs., 1 tab., 6 figs

State-of-the-art in analytical characterization of high purity solid ...

Indian Academy of Sciences (India)

Facilities and some results of several spectroscopic methods which have potential applications in the field of analysis of solid high purity substances and which have been elaborated in Russia, will be discussed in this paper. Laser nondispersive atomic fluorescence method with glow discharge cathode sputtering atomiser, ...

Fabrication of novel cryomill for synthesis of high purity metallic nanoparticles

Science.gov (United States)

Kumar, Nirmal; Biswas, Krishanu

2015-08-01

The successful preparation of free standing metal nanoparticles with high purity in bulk quantity is the pre-requisite for any potential application. This is possible by using ball milling at cryogenic temperature. However, the most of ball mills available in the market do not allow preparing high purity metal nanoparticles by this route. In addition, it is not possible to carry out in situ measurements of process parameters as well as diagnostic of the process. In the present investigation, we present a detailed study on the fabrication of a cryomill, which is capable of avoiding contaminations in the product. It also provides in situ measurements and diagnostic of the low temperature milling process. Online monitoring of the milling temperature and observation of ball motion are the important aspects in the newly designed mill. The nanoparticles prepared using this fabricated mill have been found to be free standing and also free from contaminations.

Purity, adulteration and price of drugs bought on-line versus off-line in the Netherlands.

Science.gov (United States)

van der Gouwe, Daan; Brunt, Tibor M; van Laar, Margriet; van der Pol, Peggy

2017-04-01

On-line drug markets flourish and consumers have high expectations of on-line quality and drug value. The aim of this study was to (i) describe on-line drug purchases and (ii) compare on-line with off-line purchased drugs regarding purity, adulteration and price. Comparison of laboratory analyses of 32 663 drug consumer samples (stimulants and hallucinogens) purchased between January 2013 and January 2016, 928 of which were bought on-line. The Netherlands. Primary outcome measures were (i) the percentage of samples purchased on-line and (ii) the chemical purity of powders (or dosage per tablet); adulteration; and the price per gram, blotter or tablet of drugs bought on-line compared with drugs bought off-line. The proportion of drug samples purchased on-line increased from 1.4% in 2013 to 4.1% in 2015. The frequency varied widely, from a maximum of 6% for controlled, traditional substances [ecstasy tablets, 3,4-methylenedioxy-methamphetamine (MDMA) powder, amphetamine powder, cocaine powder, 4-bromo-2,5-dimethoxyphenethylamine (2C-B) and lysergic acid diethylamide (LSD)] to more than a third for new psychoactive substances (NPS) [4-fluoroamphetamine (4-FA), 5/6-(2-aminopropyl)benzofuran (5/6-APB) and methoxetamine (MXE)]. There were no large differences in drug purity, yet small but statistically significant differences were found for 4-FA (on-line 59% versus off-line 52% purity for 4-FA on average, P = 0.001), MDMA powders (45 versus 61% purity for MDMA, P = 0.02), 2C-B tablets (21 versus 10 mg 2C-B/tablet dosage, P = 0.49) and ecstasy tablets (131 versus 121 mg MDMA/tablet dosage, P = 0.05). The proportion of adulterated samples purchased on-line and off-line did not differ, except for 4-FA powder, being less adulterated on-line (χ 2  = 8.3; P < 0.02). Drug prices were mainly higher on-line, ranging for various drugs from 10 to 23% higher than that of drugs purchased off-line (six of 10 substances: P < 0.05). Dutch drug users increasingly

Obtaining high purity silica from rice hulls

Directory of Open Access Journals (Sweden)

José da Silva Júnior

2010-01-01

Full Text Available Many routes for extracting silica from rice hulls are based on direct calcining. These methods, though, often produce silica contaminated with inorganic impurities. This work presents the study of a strategy for obtaining silica from rice hulls with a purity level adequate for applications in electronics. The technique is based on two leaching steps, using respectively aqua regia and Piranha solutions, which extract the organic matrix and inorganic impurities. The material was characterized by Fourier-transform infrared spectroscopy (FTIR, powder x-ray diffraction (XRD, x-ray fluorescence (XRF, scanning electron microscopy (SEM, particle size analysis by laser diffraction (LPSA and thermal analysis.

Neutron activation analysis of high purity tellurium

International Nuclear Information System (INIS)

Gil'bert, Eh.N.; Verevkin, G.V.; Obrazovskij, E.G.; Shatskaya, S.S.

1980-01-01

A scheme of neutron activation analysis of high purity tellurium is developed. Weighed amount of Te (0.5 g) is irradiated for 20-40 hr in the flux of 2x10 13 neutron/(cm 2 xs). After decomposition of the sample impurities of gold and palladium are determined by the extraction with organic sulphides. Tellurium separation from the remaining impurities is carried out by the extraction with monothiobenzoic acid from weakly acidic HCl solutions in the presence of iodide-ions, suppressing silver extraction. Remaining impurity elements in the refined product are determined γ-spectrometrically. The method allows to determine 34 impurities with determination limits 10 -6 -10 -11 g

Neutron activation analysis of high-purity zinc

International Nuclear Information System (INIS)

Khodzhamberdyeva, A.A.; Usmanova, M.M.; Gil'bert, Eh.N.; Ivanov, I.M.; Yankovskaya, T.A.; Kholyavko, E.P.

1987-01-01

The methods of neutron activation analysis of high-purity zinc with preliminary separation of the zinc base using extraction by trialkylbenzylammonium rhodanide in carbon tetrachloride from 0.5-2.0 M nitric acid solutions is developed. Only rhenium is quantitatively extracted together with zinc. Gold, iridium and molybdenum are extracted to 50-60%, and selenium - to 20%. The Na, K, La, Cr, Sc, Co, Cs, Rb, Fe, Zr, Sn, Te, As, Cd, Hf, W, Sb, Sm impurities remain in the aqueous phase. The methods permits to determine the impurities above with detection limits from 1x10 -6 to 4x10 -11 g

Firewalls from double purity

Science.gov (United States)

Bousso, Raphael

2013-10-01

The firewall paradox is often presented as arising from double entanglement, but I argue that more generally the paradox is double purity. Near-horizon modes are purified by the interior, in the infalling vacuum. Hence, they cannot also be pure alone, or in combination with any third system, as demanded by unitarity. This conflict arises independently of the Page time, for entangled and for pure states. It implies that identifications of Hilbert spaces cannot resolve the paradox. Traditional complementarity requires the unitary identification of infalling matter with a scrambled subsystem of the Hawking radiation. Extending this map to the infalling vacuum overdetermines the out-state. More general complementarity maps (“A=RB,” “ER=EPR”) necessarily fail when the near-horizon zone is pure. I argue that pure-zone states span the microcanonical ensemble, and that this suffices to make the horizon a special place. I advocate that the ability to detect the horizon locally, rather than the degree or probability of violence, is what makes firewalls problematic. Conversely, if the production of matter at the horizon can be dynamically understood and shown to be consistent, then firewalls do not constitute a violation of the equivalence principle.

Technology for sodium purity control

Energy Technology Data Exchange (ETDEWEB)

Jeong, Ji Young; Kim, B. H.; Kim, T. J. [Korea Atomic Energy Research Institute, Taejon (Korea)

1999-10-01

When sodium is used as heat transfer fluid, the plugging in coolant flow, the corrosion of structure material and the transfer of radioactive material caused by the impurities in sodium are worth considerable. Accordingly, these impurities must be monitored and controlled continuously by sodium purification devices in the heat transfer system which sodium is used as coolant. Sodium purification loop was constructed for the purpose of accumulating the technology for purity control of the coolant, developing and verifying further efficient instruments for sodium purification. The plugging meter and the cold trap is used as the implement for measuring and controlling the oxygen and the hydrogen, the main impurities in sodium coolant. They are capable of excellent performance as the implements which could detect and monitor the impurities to the concentration limit required for nuclear reactor. Sodium purification loop could be used variably according to the experimental purpose. 18 refs., 34 figs., 8 tabs. (Author)

Effects of a laser beam profile on Zeeman electromagnetically induced transparency in the Rb buffer gas cell

International Nuclear Information System (INIS)

Nikolić, S N; Radonjić, M; Krmpot, A J; Lučić, N M; Zlatković, B V; Jelenković, B M

2013-01-01

Electromagnetically induced transparency (EIT) due to Zeeman coherences in the Rb buffer gas cell is studied for different laser beam profiles, laser beam radii and intensities from 0.1 to 10 mW cm −2 . EIT line shapes can be approximated by the Lorentzian for wide Gaussian laser beam (6.5 mm in diameter) if laser intensity is weak and for a Π laser beam profile of the same diameter. Line shapes of EIT become non-Lorentzian for the Gaussian laser beam if it is narrow (1.3 mm in diameter) or if it has a higher intensity. EIT amplitudes and linewidths, for both laser beam profiles of the same diameter, have very similar behaviour regarding laser intensity and Rb cell temperature. EIT amplitudes are maximal at a certain laser beam intensity and this intensity is higher for narrower laser beams. The EIT linewidth estimated at zero laser intensity is about 50 nT or 0.7 kHz, which refers to 1.5 ms relaxation times of Zeeman coherences in 87 Rb atoms in our buffer gas cell. Blocking of the centre of the wide Gaussian laser beam in front of the photo detector yields Lorentzian profiles with a much better contrast to the linewidth ratio for EIT at higher intensities, above ∼2 mW cm −2 . (paper)

Correlates of Narrow Bracketing

DEFF Research Database (Denmark)

Koch, Alexander; Nafziger, Julia

We examine whether different phenomena of narrow bracketing can be traced back to some common characteristic and whether and how different phenomena are related. We find that making dominated lottery choices or ignoring the endowment when making risky choices are related phenomena and are both as...

Various analytical techniques used for the measurement of isotopic purity of heavy water at Madras Atomic Power Station

International Nuclear Information System (INIS)

Satyanarayanan, V.; Umapathy, P.; Bhaskaran, R.; Nagarajan, J.; Pradeep, Jeena; Ayyar, S.R.

2008-01-01

The paper deals with the various techniques used for the measurement of isotopic purity of heavy water samples received from different sources viz. reactor systems, heavy water upgrading plant and fresh consignment from heavy water production plants. Heavy water is used in PHWRs as moderator and primary coolant. Isotopic Purity is an important parameter to be monitored/analysed regularly for both the systems. There is a minimum isotopic purity level to be maintained in the moderator system due to neutron economy/fuel burnup and in the case of coolant system the measurement is of paramount importance due to its safety considerations. The selection of the method of analysis depends on the isotopic range. The techniques used to measure the isotopic purity of heavy water are a) Infrared Spectrophotometry b) Refractometry c) Densitometry. Infrared spectrometer uses the property of molecular absorption of IR radiation by HOD species and the absorbance is the measure of isotopic purity. This technique is generally used for measuring high isotopic (80-99.98%) and low isotopic samples. Refractometer uses the property of refractive index of heavy water. The difference in refractive indices of light water and heavy water is 0.0048. A 1 % change in D 2 O concentration would thus equal to 0.000048 refractive index units. This method is used for determining the approximate isotopic value of a sample. Density meter uses the property of difference in densities of light and heavy water. The difference in density of 99.999% D 2 O and light water is 0.107540 which covers the whole range of interest. The experience gained with these techniques in the measurements of isotopic purity of various samples are presented in this paper. (author)

An enhanced narrow-band imaging method for the microvessel detection

Science.gov (United States)

Yu, Feng; Song, Enmin; Liu, Hong; Wan, Youming; Zhu, Jun; Hung, Chih-Cheng

2018-02-01

A medical endoscope system combined with the narrow-band imaging (NBI), has been shown to be a superior diagnostic tool for early cancer detection. The NBI can reveal the morphologic changes of microvessels in the superficial cancer. In order to improve the conspicuousness of microvessel texture, we propose an enhanced NBI method to improve the conspicuousness of endoscopic images. To obtain the more conspicuous narrow-band images, we use the edge operator to extract the edge information of the narrow-band blue and green images, and give a weight to the extracted edges. Then, the weighted edges are fused with the narrow-band blue and green images. Finally, the displayed endoscopic images are reconstructed with the enhanced narrow-band images. In addition, we evaluate the performance of enhanced narrow-band images with different edge operators. Experimental results indicate that the Sobel and Canny operators achieve the best performance of all. Compared with traditional NBI method of Olympus company, our proposed method has more conspicuous texture of microvessel.

Acquisition and visualization techniques for narrow spectral color imaging.

Science.gov (United States)

Neumann, László; García, Rafael; Basa, János; Hegedüs, Ramón

2013-06-01

This paper introduces a new approach in narrow-band imaging (NBI). Existing NBI techniques generate images by selecting discrete bands over the full visible spectrum or an even wider spectral range. In contrast, here we perform the sampling with filters covering a tight spectral window. This image acquisition method, named narrow spectral imaging, can be particularly useful when optical information is only available within a narrow spectral window, such as in the case of deep-water transmittance, which constitutes the principal motivation of this work. In this study we demonstrate the potential of the proposed photographic technique on nonunderwater scenes recorded under controlled conditions. To this end three multilayer narrow bandpass filters were employed, which transmit at 440, 456, and 470 nm bluish wavelengths, respectively. Since the differences among the images captured in such a narrow spectral window can be extremely small, both image acquisition and visualization require a novel approach. First, high-bit-depth images were acquired with multilayer narrow-band filters either placed in front of the illumination or mounted on the camera lens. Second, a color-mapping method is proposed, using which the input data can be transformed onto the entire display color gamut with a continuous and perceptually nearly uniform mapping, while ensuring optimally high information content for human perception.

EPR and Fluorescence Spectroscopy in the Photodegradation Study of Arabian and Colombian Crude Oils

Directory of Open Access Journals (Sweden)

Carmen L. B. Guedes

2006-01-01

W/m2. The reduction in the linewidth of the free radical of 9.8% in Arabian oil and 18.5% in Colombian oil, as well as the decrease in radical numbers, indicated photochemical degradation, especially in Colombian oil. The linewidth narrowing corresponding to free radicals in the irradiated oils occurred due to the rearrangement among radicals and aromatic carbon consumption. The irradiated oils showed a reduction in the relative intensity of fluorescence of the aromatics with high molecular mass, polar aromatics, and asphaltene. The fluorescent fraction was reduced by 61% in Arabian oil and 72% in Colombian oil, corresponding to photochemical degradation of crude oil aromatic compounds.

Thulium distributed-feedback fiber lasers

DEFF Research Database (Denmark)

Agger, Søren Dyøe

2006-01-01

in silica and the fabri- cation, design and characterization of coherent Distributed Feed-Back (DFB) ber lasers incorporating thulium as the active laser medium. Our recent results have proved that single-frequency, single-polarization, narrow-linewidth (tens of kHz) operation of thulium doped DFB ber...... lasers is possible. Demonstrations of single-frequency lasers have, until now, been achieved at 1740 nm, 1984 nm and at a record-breaking 2090 nm. The 1740 nm laser has been boosted to 60 mW of output power with a linewidth of only 3 kHz and implemented in a plug-and-play turnkey system with SMF28-APC...

Simultaneous determination of dysprosium, holmium and erbium in high purity rare earth oxides by second order derivative spectrophotometry

International Nuclear Information System (INIS)

Anbu, M.; Prasada Rao, T.; Iyer, C. S. P.; Damodaran, A. D.

1996-01-01

High purity individual rare earth oxides are increasingly used as major components in lasers (Y 2 O 3 ), phosphors (YVO 3 , Eu 2 O 3 ), magnetic bubble memory films (Gd 2 O 3 ) and refractive-index lenses and fibre optics (La 2 O 3 ). The determination of individual lanthanides in high purity rare earth oxides is a more important and difficult task. This paper reports the utilization of higher order derivative spectrophotometry for the simultaneous determination of dysprosium, holmium and erbium in high purity rare earth oxides. The developed procedure is simple, reliable and allows the determination of 0.001 to 0.2% of dysprosium, holmium and erbium in several rare earth. (author). 9 refs, 2 figs, 2 tabs

Recycling of high purity selenium from CIGS solar cell waste materials

Energy Technology Data Exchange (ETDEWEB)

Gustafsson, Anna M.K., E-mail: anna.gustafsson@chalmers.se; Foreman, Mark R.StJ.; Ekberg, Christian

2014-10-15

Highlights: • A new method for recycling of selenium from CIGS solar cell materials is presented. • Separation of selenium as selenium dioxide after heating in oxygen atmosphere. • Complete selenium separation after oxidation of <63 μm particles at 800 °C for 1 h. • After reduction of selenium dioxide the selenium purity was higher than 99.999 wt%. - Abstract: Copper indium gallium diselenide (CIGS) is a promising material in thin film solar cell production. To make CIGS solar cells more competitive, both economically and environmentally, in comparison to other energy sources, methods for recycling are needed. In addition to the generally high price of the material, significant amounts of the metals are lost in the manufacturing process. The feasibility of recycling selenium from CIGS through oxidation at elevated temperatures was therefore examined. During oxidation gaseous selenium dioxide was formed and could be separated from the other elements, which remained in solid state. Upon cooling, the selenium dioxide sublimes and can be collected as crystals. After oxidation for 1 h at 800 °C all of the selenium was separated from the CIGS material. Two different reduction methods for reduction of the selenium dioxide to selenium were tested. In the first reduction method an organic molecule was used as the reducing agent in a Riley reaction. In the second reduction method sulphur dioxide gas was used. Both methods resulted in high purity selenium. This proves that the studied selenium separation method could be the first step in a recycling process aimed at the complete separation and recovery of high purity elements from CIGS.

Measurement scheme for purity based on two two-body gates

Science.gov (United States)

Nakazato, H.; Tanaka, T.; Yuasa, K.; Florio, G.; Pascazio, S.

2012-04-01

A scheme for measuring the purity of a quantum system with a finite number of levels is presented. The method makes use of two swap gates and hinges only on measurements performed on a reference system, prepared in a certain pure state and coupled with the target system. Neither tomographic methods, with the complete reconstruction of the state, nor interferometric setups are needed.

Void swelling in fast reactor irradiated high purity binary iron-chromium alloys

International Nuclear Information System (INIS)

Little, E.A.; Stow, D.A.

The void swelling characteristics of a series of high purity binary iron-chromium alloys containing 0 - 615 0 C. The void swelling behaviour can be qualitatively rationalized in terms of point defect trapping and precipitation processes involving chromium atoms

Preparation of high-purity cerium nitrate; Preparacao de nitrato de cerio de alta pureza

Energy Technology Data Exchange (ETDEWEB)

Avila, Daniela Moraes; Silva Queiroz, Carlos Alberto da; Santos Mucillo, Eliana Navarro dos [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

1995-12-31

The preparation of high-purity cerium nitrate has been carried out Cerium oxide has been prepared by fractioned precipitation and ionic exchange techniques, using a concentrate with approximately 85% of cerium oxide from NUCLEMON as raw material. Five sequential ion-exchange columns with a retention capacity of 170 g each have been used. The ethylenediamine-tetraacetic acid (EDTA) was used as eluent. The cerium content has been determined by gravimetry and iodometry techniques. The resulting cerium oxide has a purity > 99%. This material was transformed in cerium nitrate to be used as precursor for the preparation of Zirconia-ceria ceramics by the coprecipitation technique. (author) 2 tabs.

Isotopic Abundance and Chemical Purity Analysis of Stable Isotope Deuterium Labeled Sudan I

Directory of Open Access Journals (Sweden)

CAI Yin-ping;LEI Wen;ZHENG Bo;DU Xiao-ning

2014-02-01

Full Text Available It is important that to analysis of the isotopic abundance and chemical purity of Sudan I-D5, which is the internal standard of isotope dilution mass spectrometry. The isotopic abundance of Sudan I-D5 is detected by “mass cluster” classification method and LC-MS. The repeatability and reproducibility experiments were carried out by using different mass spectrometers and different operators. The RSD was less than 0.1%, so the repeatability and reproducibility were satisfactory. The accuracy and precision of the isotopic abundance analysis method was good with the results of F test and t test. The high performance liquid chromatography (HPLC had been used for detecting the chemical purity of Sudan I-D5 as external standard method.

A CHF Model in Narrow Gaps under Saturated Boiling

International Nuclear Information System (INIS)

Park, Suki; Kim, Hyeonil; Park, Cheol

2014-01-01

Many researchers have paid a great attention to the CHF in narrow gaps due to enormous industrial applications. Especially, a great number of researches on the CHF have been carried out in relation to nuclear safety issues such as in-vessel retention for nuclear power plants during a severe accident. Analytical studies to predict the CHF in narrow gaps have been also reported. Yu et al. (2012) developed an analytical model to predict the CHF on downward facing and inclined heaters based on the model of Kandlikar et al. (2001) for an upward facing heater. A new theoretical model is developed to predict the CHF in narrow gaps under saturated pool boiling. This model is applicable when one side of coolant channels or both sides are heated including the effects of heater orientation. The present model is compared with the experimental CHF data obtained in narrow gaps. A new analytical CHF model is proposed to predict CHF for narrow gaps under saturated pool boiling. This model can be applied to one-side or two-sides heating surface and also consider the effects of heater orientation on CHF. The present model is compared with the experimental data obtained in narrow gaps with one heater. The comparisons indicate that the present model shows a good agreement with the experimental CHF data in the horizontal annular tubes. However, it generally under-predicts the experimental data in the narrow rectangular gaps except the data obtained in the gap thickness of 10 mm and the horizontal downward facing heater

Electron correlations in narrow band systems

International Nuclear Information System (INIS)

Kishore, R.

1983-01-01

The effect of the electron correlations in narrow bands, such as d(f) bands in the transition (rare earth) metals and their compounds and the impurity bands in doped semiconductors is studied. The narrow band systems is described, by the Hubbard Hamiltonian. By proposing a local self-energy for the interacting electron, it is found that the results are exact in both atomic and band limits and reduce to the Hartree Fock results for U/Δ → 0, where U is the intra-atomic Coulomb interaction and Δ is the bandwidth of the noninteracting electrons. For the Lorentzian form of the density of states of the noninteracting electrons, this approximation turns out to be equivalent to the third Hubbard approximation. A simple argument, based on the mean free path obtained from the imaginary part of the self energy, shows how the electron correlations can give rise to a discontinous metal-nonmetal transition as proposed by Mott. The band narrowing and the existence of the satellite below the Fermi energy in Ni, found in photoemission experiments, can also be understood. (Author) [pt

Experimental Study of SBS Suppression via White Noise Phase Modulation

Science.gov (United States)

2014-02-10

fiber optical parametric amplifiers,” Opt. Communications 283, 2607-2610 (2010). [8] Coles, J. B., Kuo, B. P.-P., Alie , N., Moro, S., Bres, C.-S...V., Farley, K., Leveille, R., Galipeau, J., Majid , I., Christensen, S., Samson, B., Tankala, K. “kW level narrow linewidth Yb fiber amplifiers for

Application of Digital Image Analysis to Determine Pancreatic Islet Mass and Purity in Clinical Islet Isolation and Transplantation

Science.gov (United States)

Wang, Ling-jia; Kissler, Hermann J; Wang, Xiaojun; Cochet, Olivia; Krzystyniak, Adam; Misawa, Ryosuke; Golab, Karolina; Tibudan, Martin; Grzanka, Jakub; Savari, Omid; Grose, Randall; Kaufman, Dixon B; Millis, Michael; Witkowski, Piotr

2015-01-01

Pancreatic islet mass, represented by islet equivalent (IEQ), is the most important parameter in decision making for clinical islet transplantation. To obtain IEQ, the sample of islets is routinely counted manually under a microscope and discarded thereafter. Islet purity, another parameter in islet processing, is routinely acquired by estimation only. In this study, we validated our digital image analysis (DIA) system developed using the software of Image Pro Plus for islet mass and purity assessment. Application of the DIA allows to better comply with current good manufacturing practice (cGMP) standards. Human islet samples were captured as calibrated digital images for the permanent record. Five trained technicians participated in determination of IEQ and purity by manual counting method and DIA. IEQ count showed statistically significant correlations between the manual method and DIA in all sample comparisons (r >0.819 and p islet particle number (IPN) and the IEQ/IPN ratio did not differ statistically between manual counting method and DIA. In conclusion, the DIA used in this study is a reliable technique in determination of IEQ and purity. Islet sample preserved as a digital image and results produced by DIA can be permanently stored for verification, technical training and islet information exchange between different islet centers. Therefore, DIA complies better with cGMP requirements than the manual counting method. We propose DIA as a quality control tool to supplement the established standard manual method for islets counting and purity estimation. PMID:24806436

A Cultural Look at Moral Purity: Wiping the Face Clean

Directory of Open Access Journals (Sweden)

Spike W. S. eLee

2015-05-01

Full Text Available Morality is associated with bodily purity in the custom of many societies. Does that imply moral purity is a universal psychological phenomenon? Empirically, it has never been examined, as all prior experimental data came from Western samples. Theoretically, we suggest the answer is not so straightforward—it depends on the kind of universality under consideration. Combining perspectives from cultural psychology and embodiment, we predict a culture-specific form of moral purification. Specifically, given East Asians’ emphasis on the face as a representation of public self-image, we hypothesize that facial purification should have particularly potent moral effects in a face culture. Data show that face-cleaning (but not hands-cleaning reduces guilt and regret most effectively against a salient East Asian cultural background. It frees East Asians from guilt-driven prosocial behavior. In the wake of their immorality, they find a face-cleaning product especially appealing and spontaneously choose to wipe their face clean. These patterns highlight both culturally variable and universal aspects of moral purification. They further suggest an organizing principle that informs the vigorous debate between embodied and amodal perspectives.

Fracture strength and probability of survival of narrow and extra-narrow dental implants after fatigue testing: In vitro and in silico analysis.

Science.gov (United States)

Bordin, Dimorvan; Bergamo, Edmara T P; Fardin, Vinicius P; Coelho, Paulo G; Bonfante, Estevam A

2017-07-01

To assess the probability of survival (reliability) and failure modes of narrow implants with different diameters. For fatigue testing, 42 implants with the same macrogeometry and internal conical connection were divided, according to diameter, as follows: narrow (Ø3.3×10mm) and extra-narrow (Ø2.9×10mm) (21 per group). Identical abutments were torqued to the implants and standardized maxillary incisor crowns were cemented and subjected to step-stress accelerated life testing (SSALT) in water. The use-level probability Weibull curves, and reliability for a mission of 50,000 and 100,000 cycles at 50N, 100, 150 and 180N were calculated. For the finite element analysis (FEA), two virtual models, simulating the samples tested in fatigue, were constructed. Loading at 50N and 100N were applied 30° off-axis at the crown. The von-Mises stress was calculated for implant and abutment. The beta (β) values were: 0.67 for narrow and 1.32 for extra-narrow implants, indicating that failure rates did not increase with fatigue in the former, but more likely were associated with damage accumulation and wear-out failures in the latter. Both groups showed high reliability (up to 97.5%) at 50 and 100N. A decreased reliability was observed for both groups at 150 and 180N (ranging from 0 to 82.3%), but no significant difference was observed between groups. Failure predominantly involved abutment fracture for both groups. FEA at 50N-load, Ø3.3mm showed higher von-Mises stress for abutment (7.75%) and implant (2%) when compared to the Ø2.9mm. There was no significant difference between narrow and extra-narrow implants regarding probability of survival. The failure mode was similar for both groups, restricted to abutment fracture. Copyright © 2017 Elsevier Ltd. All rights reserved.

Demands made on high-purity copper for special purposes

International Nuclear Information System (INIS)

Roettges, D.

1977-01-01

The properties (electrical resistivity, residual impurities) of high-purity copper produced on a technical scale are reported as well as its practical applications. The paper discusses a high-oxygen copper (SV) with low residual resistivity at low temperatures and an oxygen-free (hydrogen-stable) copper (BE electronic) with low gas content. The SV quality has been specially developed for use as stabilizer in superconductors while the BE quality is used in high and ultrahigh vacuum. (GSC) [de

The microstructural mechanism of electromigration failure in narrow interconnects of Al alloys

Energy Technology Data Exchange (ETDEWEB)

Kim, Choongun [Univ. of California, Berkeley, CA (United States)

1993-04-01

This thesis reports a study of the mechanism of electromigration failure in Al-2Cu-1Si thin-film conducting lines on Si. Samples were patterned from 0.5 μm thick vapor-deposited films with various mean grain sizes (G), and had lines widths (W) of 1.3, 2, 4 and 6 μm. The lines were aged at various conditions to change the Cu-precipitate distribution and were tested to failure at T = 225°C and j = 2.5 x 10⁶ A/cm². Some samples were tested over a range of substrate temperatures, current densities and current reversal times. Aging produces an initially dense distribution of metastable θ' (Al₂Cu; coherent) in the grain interiors, with stable θ (Al₂Cu; incoherent) at the grain boundaries. The intragranular θ' is gradually absorbed into the grain boundary precipitates. In the wide lines the mean time to failure increases slowly and monotonically with pre-aging time and current reversal time. The failure mode is the formation and coalescence of voids that form on grain boundaries with an apparent activation energy of 0.65 eV. In the narrow lines, the lines failed by a transgranular-slit mechanism with an activation energy near 0.93 eV. The distribution of the polygranular segments and the kinetics of failure varies with the linewidths. Failure occurs after Cu has been swept from the grains that fail. Pre-aging the line to create a more stable distribution of Cu significantly increases the time to failure. When the density of intragranular θ-phase precipitates is maximized, the transgranular-slit failure mechanism is suppressed, and the bamboo grain fails by diffuse thinning to rupture. The results from the current reversal test indicate that the time to sweep Cu in the polygranular segments is longer for longer polygranular segments. Thus the time to first failure in an array of lines is much longer than predicted by a log-normal fit to the distribution of failure times.

Associations between Narrow Angle and Adult Anthropometry: The Liwan Eye Study

Science.gov (United States)

Jiang, Yuzhen; He, Mingguang; Friedman, David S.; Khawaja, Anthony P.; Lee, Pak Sang; Nolan, Winifred P.; Yin, Qiuxia; Foster, Paul J.

2015-01-01

Purpose To assess the associations between narrow angle and adult anthropometry. Methods Chinese adults aged 50 years and older were recruited from a population-based survey in the Liwan District of Guangzhou, China. Narrow angle was defined as the posterior trabecular meshwork not visible under static gonioscopy in at least three quadrants (i.e. a circumference of at least 270°). Logistic regression models were used to examine the associations between narrow angle and anthropomorphic measures (height, weight and body mass index, BMI). Results Among the 912 participants, lower weight, shorter height, and lower BMI were significantly associated with narrower angle width (tests for trend: mean angle width in degrees vs weight p<0.001; vs height p<0.001; vs BMI p = 0.012). In univariate analyses, shorter height, lower weight and lower BMI were all significantly associated with greater odds of narrow angle. The crude association between height and narrow angle was largely attributable to a stronger association with age and sex. Lower BMI and weight remained significantly associated with narrow angle after adjustment for height, age, sex, axial ocular biometric measures and education. In analyses stratified by sex, the association between BMI and narrow angle was only observed in women. Conclusion Lower BMI and weight were associated with significantly greater odds of narrow angle after adjusting for age, education, axial ocular biometric measures and height. The odds of narrow angle increased 7% per 1 unit decrease in BMI. This association was most evident in women. PMID:24707840

SDSS J211852.96-073227.5: a new γ-ray flaring narrow-line Seyfert 1 galaxy

Science.gov (United States)

Yang, Hui; Yuan, Weimin; Yao, Su; Li, Ye; Zhang, Jin; Zhou, Hongyan; Komossa, S.; Liu, He-Yang; Jin, Chichuan

2018-04-01

We report on the identification of a new γ-ray-emitting narrow-line Seyfert 1 (NLS1) galaxy, SDSS J211852.96-073227.5 (hereafter J2118-0732). The galaxy, at a redshift of 0.26, is associated with a radio source of flat/inverted spectrum at high radio frequencies. The analysis of its optical spectrum obtained in the Sloan Digital Sky Survey revealed a small linewidth of the broad component of the Hβ line (FWHM = 1585 km s-1), making it a radio-loud NLS1 galaxy - an intriguing class of active galactic nuclei with exceptional multi-wavelength properties. A new γ-ray source centred at J2118-0732 was sporadically detected during 2009-2013 in form of flares by the Fermi-LAT. Our XMM-Newton observations revealed a flat X-ray spectrum described by a simple power law, and a flux variation by a factor of ˜2.5 in 5 months. The source also shows intraday variability in the infrared band. Its broad-band spectral energy distribution can be modelled by emission from a simple one-zone leptonic jet model, and the flux drop from infrared to X-rays in five months can be explained by changes of the jet parameters, though the exact values may be subject to relatively large uncertainties. With the NLS1-blazar composite nucleus, the clear detection of the host galaxy and the synchronous variations in the multi-wavelength fluxes, J2118-0732 provides a new perspective on the formation and evolution of relativistic jets under the regime of relatively small black hole masses and high accretion rates.

A naturally narrow positive-parity Θ+

International Nuclear Information System (INIS)

Carlson, Carl E.; Carone, Christopher D.; Kwee, Herry J.; Nazaryan, Vahagn

2004-01-01

We present a consistent color-flavor-spin-orbital wave function for a positive-parity Θ + that naturally explains the observed narrowness of the state. The wave function is totally symmetric in its flavor-spin part and totally antisymmetric in its color-orbital part. If flavor-spin interactions dominate, this wave function renders the positive-parity Θ + lighter than its negative-parity counterpart. We consider decays of the Θ + and compute the overlap of this state with the kinematically allowed final states. Our results are numerically small. We note that dynamical correlations between quarks are not necessary to obtain narrow pentaquark widths

Obtention of high purity silica from the flotation waste of itabiritic ore

International Nuclear Information System (INIS)

Martins, Polyana Fabricia Fernandes

2016-01-01

Banded iron formations are exploited as iron mineral in 'Quadrilatero Ferrifero' of Minas Gerais (MG) State, Brazil. About half of the amount of extracted material becomes tailings, which are stored in tailing dams or used for filling mining pits. Tens of thousands of tons are generated daily in operating mines in this region, causing concern about the environmental liabilities, and costs to manage the tailing dams. Miners are committed to finding uses for these wastes in other productive chains. This thesis aimed to obtain high purity silica from the flotation tailings of banded iron formations using classical techniques for ore processing, such as particle size classification and magnetic separation, followed by hydrometallurgical leaching, also alkaline fusion and chemical precipitation. The tailings samples was collected in the tailings dam of Peak Mine operated by Vale A.S., in Itabirito – MG. This sample had initially 33.4% by weight SiO 2 , 57.4% wt Fe 2 O 3 and 8.31% wt Al 2 O 3 . After desliming for disposal of the fine particles (-37μm) the composition was 68.0% SiO 2 , 31.4% Fe 2 O 3 and 0.50% Al 2 O 3 . After magnetic separation, the composition was 93.8% SiO 2 , 1.16% Fe 2 O 3 and 3.80% Al 2 O 3 . After acid leaching l or digestion to remove impurities, it was possible to obtain silica with 98% purity. The fusion with sodium hydroxide, followed by alkaline leaching of sodium silicate and silica precipitation gave purities of about 99.5%. Values even higher may be possible with optimization of the parameters of alkaline fusion or by repeating the process from the product with purity of 99.5%. The iron oxide content and the aluminum main contaminants were 0.01% and 0.07%, respectively. Amorphous silica was obtained with high specific surface (322 m 2 /g) and particle size less than 200 nm. Depending on the application, a control should be made for the impurities, such as phosphorus, potassium and boron. (author)

Cross Purposes: Love and Purity at a Puerto Rican Protestant High School

Science.gov (United States)

Seale-Collazo, James

2013-01-01

A "native" Christian ethnographer finds religious education at this church-sponsored school to pursue two distinct, and occasionally conflicting, curricula: "love" and "purity." The curriculum of love draws on what Turner called liminality and communitas in an effort to promote spiritual "encounters with…

Law and Behavioral Sciences: Why We Need Less Purity Rather than More

NARCIS (Netherlands)

P. Mascini (Peter)

2016-01-01

markdownabstractIn his inaugural lecture, Peter Mascini takes issue with the goal of scientific purity in the behavioral study of the law, conceived as the deliberate choice to postulate a limited number of universally applicable behavioral principles. The guiding principle of behavioral sociology

Research of the mode instability threshold in high power double cladding Yb-doped fiber amplifiers

Energy Technology Data Exchange (ETDEWEB)

Wang, Yanshan; Ma, Yi; Sun, Yinhong; Peng, Wanjing; Tang, Chun [Institute of Applied Electronics, CAEP, Mianyang, Sichuan (China); The Key Laboratory of Science and Technology on High Energy Laser, CAEP, Mianyang, Sichuan (China); Liu, Qinyong; Ke, Weiwei [Institute of Applied Physics and Computational Mathematics, CAEP, Beijing (China); Wang, Xiaojun [Institute of Applied Physics and Computational Mathematics, CAEP, Beijing (China); Technical Institute of Physics and Chemistry, CAS, Beijing (China)

2017-08-15

We experimentally investigate the behavior of the mode instability (MI) threshold in the double cladding Yb-doped fiber amplifier when the amplifier is pumped by broad linewidth laser diodes and narrow linewidth laser diodes respectively. It is found that the MI threshold increases by 26% when the amplifier is pumped by the broad linewidth laser diodes. Experiment results show that the MI threshold is affected by the local heat load rather than the average or the total heat load. The calculation shows that the local heat deposit actually plays the key role to stimulate the MI behaviour. At the MI threshold position in the fiber, the local heat deposit also changes dramatically. The effect of the thermal conductivity on the MI threshold is also studied. Our investigation shows that the MI threshold increases from 1269 W to 1950 W when the thermal conductivity of the fiber amplifier is increased from 0.3 W/(m . K) to 5 W/(m . K). Through optimizing the pump linewidth and the cooling efficiency of the gain fiber, the MI threshold is doubled in our experiment. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Research of the mode instability threshold in high power double cladding Yb-doped fiber amplifiers

International Nuclear Information System (INIS)

Wang, Yanshan; Ma, Yi; Sun, Yinhong; Peng, Wanjing; Tang, Chun; Liu, Qinyong; Ke, Weiwei; Wang, Xiaojun

2017-01-01

We experimentally investigate the behavior of the mode instability (MI) threshold in the double cladding Yb-doped fiber amplifier when the amplifier is pumped by broad linewidth laser diodes and narrow linewidth laser diodes respectively. It is found that the MI threshold increases by 26% when the amplifier is pumped by the broad linewidth laser diodes. Experiment results show that the MI threshold is affected by the local heat load rather than the average or the total heat load. The calculation shows that the local heat deposit actually plays the key role to stimulate the MI behaviour. At the MI threshold position in the fiber, the local heat deposit also changes dramatically. The effect of the thermal conductivity on the MI threshold is also studied. Our investigation shows that the MI threshold increases from 1269 W to 1950 W when the thermal conductivity of the fiber amplifier is increased from 0.3 W/(m . K) to 5 W/(m . K). Through optimizing the pump linewidth and the cooling efficiency of the gain fiber, the MI threshold is doubled in our experiment. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Aluminum anode for aluminum-air battery - Part I: Influence of aluminum purity

Science.gov (United States)

Cho, Young-Joo; Park, In-Jun; Lee, Hyeok-Jae; Kim, Jung-Gu

2015-03-01

2N5 commercial grade aluminum (99.5% purity) leads to the lower aluminum-air battery performances than 4N high pure grade aluminum (99.99% purity) due to impurities itself and formed impurity complex layer which contained Fe, Si, Cu and others. The impurity complex layer of 2N5 grade Al declines the battery voltage on standby status. It also depletes discharge current and battery efficiency at 1.0 V which is general operating voltage of aluminum-air battery. However, the impurity complex layer of 2N5 grade Al is dissolved with decreasing discharge voltage to 0.8 V. This phenomenon leads to improvement of discharge current density and battery efficiency by reducing self-corrosion reaction. This study demonstrates the possibility of use of 2N5 grade Al which is cheaper than 4N grade Al as the anode for aluminum-air battery.

Dissolution of high-purity lead and subsequent crystal growth during the preparation of corrosion coupons

Energy Technology Data Exchange (ETDEWEB)

McGarvey, G.B. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); McDougall, T.E.; Owen, D.G. [Atomic Energy of Canada Limited, Pinawa, Manitoba (Canada)

1997-07-01

High-purity lead discs were prepared using several combinations of polishing, rinsing and ultrasonic treatment. Physical degradation of the lead surface and the premature generation and deposition of oxides on the surface were observed for certain combinations of preparation steps. Ultrasonic treatment of the discs was found to be particularly detrimental as it induced significant crystal growth and, in several instances, deterioration of the polished surface. Simple air drying of freshly rinsed discs also led to oxide formation on the surface after as short a time as 1 min. An effective method for preparing discs from high-purity lead is described. (author)

Dissolution of high-purity lead and subsequent crystal growth during the preparation of corrosion coupons

International Nuclear Information System (INIS)

McGarvey, G.B.; McDougall, T.E.; Owen, D.G.

1997-01-01

High-purity lead discs were prepared using several combinations of polishing, rinsing and ultrasonic treatment. Physical degradation of the lead surface and the premature generation and deposition of oxides on the surface were observed for certain combinations of preparation steps. Ultrasonic treatment of the discs was found to be particularly detrimental as it induced significant crystal growth and, in several instances, deterioration of the polished surface. Simple air drying of freshly rinsed discs also led to oxide formation on the surface after as short a time as 1 min. An effective method for preparing discs from high-purity lead is described. (author)

Subglottic cysts and asymmetrical subglottic narrowing on neck radiograph

International Nuclear Information System (INIS)

Holinger, L.D.; Torium, D.M.; Anandappa, E.C.

1988-01-01

The congenital subglottic hemangioma typically appears as an asymmetric subglottic narrowing or mass on frontal neck radiograph. Therefore, soft tissue neck radiography has been advocated as a definitive non-operative approach for diagnosing these lesions. However, we have noted similar asymmetric subglottic narrowing in patients with acquired subglottic cysts. These retention cysts occur following long-term intubation in the neonate. The mechanism probably involves subglottic fibrosis which obstructs glands with subsequent cyst formation. Acquired subglottic cysts typically appear as an asymmetric narrowing on frontal or lateral soft tissue neck radiographs. These lesions may produce airway compromise but are effectively treated by forceps or laser removal. Acquired subglottic cysts must be included in the differential diagnosis of asymmetric subglottic narrowing. The definitive diagnosis is made by direct laryngoscopy, not soft tissue neck radiograph. (orig.)

High purity samarium oxide from mixed rare earth carbonates

International Nuclear Information System (INIS)

Queiroz, Carlos A. da S.; Seneda, Jose A.; Vasconcellos, Mari E. de; Pedreira Filho, Walter dos R.

2013-01-01

A simple and economical chemical process for the production of highly pure samarium oxides is discussed. The raw material, which was used in the form of rare earth carbonates was produced industrially from the chemical treatment of Brazilian monazite. Ion exchange chromatography was performed using a strong cationic resin that is typically employed in water treatment processes to fractionate rare earth elements (REE) without the use of retention ions. Under these conditions, 99.9% pure Sm 2 O 3 was eluted using the ammonium salt of ethylenediaminetetraacetic acid (EDTA) at a controlled pH. The EDTA-samarium complex was separated from EDTA and then precipitated as oxalate and fired to samarium oxide. Molecular absorption spectrophotometry was used to monitor the samarium content during the proposed process, and sector field inductively coupled plasma mass spectrometry was used to certify the purity of the samarium oxide. Typical samarium oxide obtained from the proposed procedure contained the following contaminants in micrograms per gram: Sc (20.90); Y (11.80); La (8.4); Ce (4.3); Pr (2.5); Nd (5.1); Eu (94); Gd (114); Tb (3.6); Dy (2.5), Ho (2.3); Er (3.0); Tm (2.3); Yb (38,2); Lu (25.6). The high-purity samarium oxides produced in the present study can be used as an alternative to imported products in research and development applications. (author)

Trace elements in high purity materials for advanced technology: contribution of neutron activation analysis and radioanalytical technique

International Nuclear Information System (INIS)

Gallorini, M.; Pietra, R.; Sabbioni, E.

1991-01-01

Neutron activation analysis and radioanalytical techniques have been employed to investigate problems related to trace elements and high purity technology materials. Applications of these techniques are overviewed: semiconductor technology as in the case of As and In ion implantation in high purity silicon; problems related to trace elements impurities in thermometric measurements; coating materials to prevent trace elements contamination in biological sampling and metals release from human prostheses. (author) 8 refs.; 2 figs.; 8 tabs

Native oxidation of ultra high purity Cu bulk and thin films

International Nuclear Information System (INIS)

Iijima, J.; Lim, J.-W.; Hong, S.-H.; Suzuki, S.; Mimura, K.; Isshiki, M.

2006-01-01

The effect of microstructure and purity on the native oxidation of Cu was studied by using angle-resolved X-ray photoelectron spectroscopy (AR-XPS) and spectroscopic ellipsometry (SE). A high quality copper film prepared by ion beam deposition under a substrate bias voltage of -50 V (IBD Cu film at V s = -50 V) showed an oxidation resistance as high as an ultra high purity copper (UHP Cu) bulk, whereas a Cu film deposited without substrate bias voltage (IBD Cu film at V s = 0 V) showed lower oxidation resistance. The growth of Cu 2 O layer on the UHP Cu bulk and both types of the films obeyed in principle a logarithmic rate law. However, the growth of oxide layer on the IBD Cu films at V s = 0 and -50 V deviated upward from the logarithmic rate law after the exposure time of 320 and 800 h, respectively. The deviation from the logarithmic law is due to the formation of CuO on the Cu 2 O layer after a critical time

Efficiency of alfalfa seed processing with different seed purity

OpenAIRE

Đokić, Dragoslav; Stanisavljević, Rade; Terzić, Dragan; Milenković, Jasmina; Radivojević, Gordana; Koprivica, Ranko; Štrbanović, Ratibor

2015-01-01

The work was carried out analysis of the impact of the initial purity of raw alfalfa seed on the resulting amount of processed seed in the processing. Alfalfa is very important perennial forage legume which is used for fodder and seed production. Alfalfa seed is possible to achieve high yields and very good financial effects. To obtain the seed material with good characteristics complex machines for cleaning and sorting seeds are used. In the processing center of the Institute for forage crop...

Process for the production of high purity deuterium

International Nuclear Information System (INIS)

Arrathoon, R.

1977-01-01

A process for the electrolysis of heavy water which results in the production of high purity deuterium without periodic replenishment of the electrolyte with additional deuterated compounds is defined. Electrolysis is effected through the use of an inexpensive cation-action permselective membrane which is essentially a solid polymer electrolyte and which is capable of automatically separating the evolved deuterium and oxygen gas. This cation-active permselective membrane does not introduce any intrinsic impurities or tritium contamination in the generated deuterium gas, does not require periodic revitalization with deuterated compounds or other chemical compounds, and is characterized by an unusually high electrical efficiency

Design, Construction, Demonstration and Delivery of an Automated Narrow Gap Welding System.

Science.gov (United States)

1982-06-29

DESIGN, CONSTRUCTION, DEMONSTRATION AND DELIVERY OF WE DA4I &NARROW GAP CONTRACT NO. NOOGOO-81-C-E923 TO DAVID TAYLOR NAVAL RESEARCH AND DEVELOPMENT...the automated * Narrow Gap welding process, is the narrow (3/8 - inch), square-butt joint *design. This narrow joint greatly reduces the volume of weld...AD-i45 495 DESIGN CONSTRUCTION DEMONSTRATION AiND DELIVERY OF RN 1/j AUrOMATED NARROW GAP WELDING SYSTEMI() CRC AUTOMATIC WELDING CO HOUSTON TX 29

Injection Locking of a Semiconductor Double Quantum Dot Micromaser.

Science.gov (United States)

Liu, Y-Y; Stehlik, J; Gullans, M J; Taylor, J M; Petta, J R

2015-11-01

Emission linewidth is an important figure of merit for masers and lasers. We recently demonstrated a semiconductor double quantum dot (DQD) micromaser where photons are generated through single electron tunneling events. Charge noise directly couples to the DQD energy levels, resulting in a maser linewidth that is more than 100 times larger than the Schawlow-Townes prediction. Here we demonstrate a linewidth narrowing of more than a factor 10 by locking the DQD emission to a coherent tone that is injected to the input port of the cavity. We measure the injection locking range as a function of cavity input power and show that it is in agreement with the Adler equation. The position and amplitude of distortion sidebands that appear outside of the injection locking range are quantitatively examined. Our results show that this unconventional maser, which is impacted by strong charge noise and electron-phonon coupling, is well described by standard laser models.

Critical slowing down of spin fluctuations in BiFeO3

International Nuclear Information System (INIS)

Scott, J F; Singh, M K; Katiyar, R S

2008-01-01

In earlier work we reported the discovery of phase transitions in BiFeO 3 evidenced by divergences in the magnon light-scattering cross-sections at 140 and 201 K (Singh et al 2008 J. Phys.: Condens. Matter 20 252203) and fitted these intensity data to critical exponents α = 0.06 and α' = 0.10 (Scott et al 2008 J. Phys.: Condens. Matter 20 322203), under the assumption that the transitions are strongly magnetoelastic (Redfern et al 2008 at press) and couple to strain divergences through the Pippard relationship (Pippard 1956 Phil. Mag. 1 473). In the present paper we extend those criticality studies to examine the magnon linewidths, which exhibit critical slowing down (and hence linewidth narrowing) of spin fluctuations. The linewidth data near the two transitions are qualitatively different and we cannot reliably extract a critical exponent ν, although the mean field value ν = 1/2 gives a good fit near the lower transition.

Narrow Escape of Interacting Diffusing Particles

Science.gov (United States)

Agranov, Tal; Meerson, Baruch

2018-03-01

The narrow escape problem deals with the calculation of the mean escape time (MET) of a Brownian particle from a bounded domain through a small hole on the domain's boundary. Here we develop a formalism which allows us to evaluate the nonescape probability of a gas of diffusing particles that may interact with each other. In some cases the nonescape probability allows us to evaluate the MET of the first particle. The formalism is based on the fluctuating hydrodynamics and the recently developed macroscopic fluctuation theory. We also uncover an unexpected connection between the narrow escape of interacting particles and thermal runaway in chemical reactors.

High-purity Cu nanocrystal synthesis by a dynamic decomposition method

OpenAIRE

Jian, Xian; Cao, Yu; Chen, Guozhang; Wang, Chao; Tang, Hui; Yin, Liangjun; Luan, Chunhong; Liang, Yinglin; Jiang, Jing; Wu, Sixin; Zeng, Qing; Wang, Fei; Zhang, Chengui

2014-01-01

Cu nanocrystals are applied extensively in several fields, particularly in the microelectron, sensor, and catalysis. The catalytic behavior of Cu nanocrystals depends mainly on the structure and particle size. In this work, formation of high-purity Cu nanocrystals is studied using a common chemical vapor deposition precursor of cupric tartrate. This process is investigated through a combined experimental and computational approach. The decomposition kinetics is researched via differential sca...

Narrow Framing and Long-Term Care Insurance

OpenAIRE

Daniel Gottlieb; Olivia S. Mitchell

2015-01-01

We propose a model of narrow framing in insurance and test it using data from a new module we designed and fielded in the Health and Retirement Study. We show that respondents subject to narrow framing are substantially less likely to buy long-term care insurance than average. This effect is distinct from, and much larger than, the effects of risk aversion or adverse selection, and it offers a new explanation for why people underinsure their later-life care needs.

Dosimetry of narrow band UVB treatments

International Nuclear Information System (INIS)

Goode, D.H.; Mannering, D.M.

1996-01-01

Full text: For many years psoriasis has been treated with broad band UVB lamps. These lamps have a bell shaped spectrum which peaks at 305 nm and extends from 280 nm to 350 nm. However research with monochromatic UV radiation has shown that wavelengths between 300 nm and 320 nm are the most efficacious for clearing psoriasis while wavelengths below 305 nm are most effective for producing the undesirable side effect of erythema (sunburn). In response to these findings Philips developed a narrow band UVB tube in which a large fraction of the output was confined to a narrow peak (bandwidth 2.5 nm) situated at 311 nm. Christchurch Hospital replaced broad band UVB with narrow band treatments in August 1995 and as this required UV exposures to be substantially increased new protocols had to be developed. Three aspects needed to be addressed. These were translating the dose from broad band to narrow band for current patients, determining the initial dose for new patients and developing a formula for increasing subsequent exposures to both types of patient. To translate doses the spectral irradiance (μW/cm 2 /nm) that would fall on the patient was measured in both the old broad band and the new narrow band treatment units and from this UV doses were calculated. All doses were expressed in mJ/cm 2 of unweighted UV over the range 250 nm to 400 nm. The erythemal effectiveness of the two units were compared by using the CIE 1987 curve to express doses in terms of the equivalent exposure of monochromatic 297 nm radiation. It was found that an exposure of 3.96 mJ/cm 2 from the broad band FS40 tubes and 12.79 mJ/cm 2 from the narrow band TL/01 tubes were both equivalent to 1.00 mJ/cm 2 of monochromatic 297 nm radiation so when transferring patients all broad band doses needed to be increased by a factor of 3.2. Before transferring any patients this factor was confirmed by conducting two minimal erythema dose (MED) tests on a normal subject, one in each unit. For new patients a

Narrow n anti n resonances

International Nuclear Information System (INIS)

Bogdanova, L.N.; Dalkarov, O.D.; Kerbikov, B.O.; Shapiro, I.S.

1975-01-01

The present status of the problem of quasinuclear states in systems of nucleons and antinucleons is reviewed. The theoretical predictions are compared with experimental data on narrow meson resonances near N anti N threshold which appeared in 1971-74

Capillary gel electrophoresis for the quantification and purity determination of recombinant proteins in inclusion bodies.

Science.gov (United States)

Espinosa-de la Garza, Carlos E; Perdomo-Abúndez, Francisco C; Campos-García, Víctor R; Pérez, Néstor O; Flores-Ortiz, Luis F; Medina-Rivero, Emilio

2013-09-01

In this work, a high-resolution CGE method for quantification and purity determination of recombinant proteins was developed, involving a single-component inclusion bodies (IBs) solubilization solution. Different recombinant proteins expressed as IBs were used to show method capabilities, using recombinant interferon-β 1b as the model protein for method validation. Method linearity was verified in the range from 0.05 to 0.40 mg/mL and a determination coefficient (r(2) ) of 0.99 was obtained. The LOQs and LODs were 0.018 and 0.006 mg/mL, respectively. RSD for protein content repeatability test was 2.29%. In addition, RSD for protein purity repeatability test was 4.24%. Method accuracy was higher than 90%. Specificity was confirmed, as the method was able to separate recombinant interferon-β 1b monomer from other aggregates and impurities. Sample content and purity was demonstrated to be stable for up to 48 h. Overall, this method is suitable for the analysis of recombinant proteins in IBs according to the attributes established on the International Conference for Harmonization guidelines. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High purity heavy water production: need for total organic carbon determination in process water streams

International Nuclear Information System (INIS)

Ayushi; Kumar, Sangita D.; Reddy, A.V.R.; Vithal, G.K.

2009-01-01

In recent times, demand for high purity heavy water (99.98% pure) in industries and laboratories has grown by manifold. Its application started in nuclear industry with the design of CANDU reactor, which uses natural uranium as fuel. In this reactor the purest grade of heavy water is used as the moderator and the primary coolant. Diverse industrial applications like fibre optics, medicine, semiconductors etc. use high purity heavy water extensively to achieve better performance of the specific material. In all these applications there is a stringent requirement that the total organic carbon content (TOC) of high purity heavy water should be very low. This is because the presence of TOC can lead to adverse interactions in different applications. To minimize the TOC content in the final product there is a need to monitor and control the TOC content at each and every stage of heavy water production. Hence a simple, rapid and accurate method was developed for the determination of TOC content in process water samples. The paper summarizes the results obtained for the TOC content in the water samples collected from process streams of heavy water production plant. (author)

Dependence on liquid temperature and purity of light emission characteristics in single cavitation bubble luminescence

Energy Technology Data Exchange (ETDEWEB)

Barbaglia, Mario O; Bonetto, Fabian J [Consejo Nacional de Investigaciones Cientificas y Tecnicas and Instituto Balseiro, Centro Atomico Bariloche, Av. Bustillo 9500, CP8400, Rio Negro (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, Instituto Balseiro, and Comision Nacional de Energia Atomica, Laboratorio de Cavitacion y Biotecnologia, Centro Atomico Bariloche, Av. Bustillo 9500, CP8400, Rio Negro (Argentina)

2004-02-15

We produced single bubbles in water using a visible pulsed laser and studied the characteristics of the light emitted during the bubble collapse time as a function of the water temperature for different water purity values. The water temperature ranged from freezing point (0 deg. C) to near boiling. We measured the luminescence pulse for the mentioned temperature range at various purity values. We also obtained the average bubble lifetime and the average luminescence pulse emitted as a function of water temperature. The main conclusion was that the luminescence can be modified by the water quality and by the water temperature. Maximum luminescence was obtained near the water freezing point.

Dependence on liquid temperature and purity of light emission characteristics in single cavitation bubble luminescence

International Nuclear Information System (INIS)

Barbaglia, Mario O.; Bonetto, Fabian J.

2004-01-01

We produced single bubbles in water using a visible pulsed laser and studied the characteristics of the light emitted during the bubble collapse time as a function of the water temperature for different water purity values. The water temperature ranged from freezing point (0 deg. C) to near boiling. We measured the luminescence pulse for the mentioned temperature range at various purity values. We also obtained the average bubble lifetime and the average luminescence pulse emitted as a function of water temperature. The main conclusion was that the luminescence can be modified by the water quality and by the water temperature. Maximum luminescence was obtained near the water freezing point

Lost Purity. Social in Nineteenth and Twentieth-century Feminisms

OpenAIRE

Paola Persano

2016-01-01

‘Social Purity’ appears in a part of the French and Anglo-Saxon (Britain and the United States) nineteenth-twentieth century’s feminisms, as a mean for many claims: from the full recognition of sexual difference in Hubertine Auclert’s social and ‘differentialist’ republicanism in France to Josephine Butler’s refusal of any purity imposed from above in England, until the absolute turn of the idea of women’s moral superiority and the equal and opposite force to the final exit from ‘the social’ ...

Detecting single viruses and nanoparticles using whispering gallery microlasers.

Science.gov (United States)

He, Lina; Ozdemir, Sahin Kaya; Zhu, Jiangang; Kim, Woosung; Yang, Lan

2011-06-26

There is a strong demand for portable systems that can detect and characterize individual pathogens and other nanoscale objects without the use of labels, for applications in human health, homeland security, environmental monitoring and diagnostics. However, most nanoscale objects of interest have low polarizabilities due to their small size and low refractive index contrast with the surrounding medium. This leads to weak light-matter interactions, and thus makes the label-free detection of single nanoparticles very difficult. Micro- and nano-photonic devices have emerged as highly sensitive platforms for such applications, because the combination of high quality factor Q and small mode volume V leads to significantly enhanced light-matter interactions. For example, whispering gallery mode microresonators have been used to detect and characterize single influenza virions and polystyrene nanoparticles with a radius of 30 nm (ref. 12) by measuring in the transmission spectrum either the resonance shift or mode splitting induced by the nanoscale objects. Increasing Q leads to a narrower resonance linewidth, which makes it possible to resolve smaller changes in the transmission spectrum, and thus leads to improved performance. Here, we report a whispering gallery mode microlaser-based real-time and label-free detection method that can detect individual 15-nm-radius polystyrene nanoparticles, 10-nm gold nanoparticles and influenza A virions in air, and 30 nm polystyrene nanoparticles in water. Our approach relies on measuring changes in the beat note that is produced when an ultra-narrow emission line from a whispering gallery mode microlaser is split into two modes by a nanoscale object, and these two modes then interfere. The ultimate detection limit is set by the laser linewidth, which can be made much narrower than the resonance linewidth of any passive resonator. This means that microlaser sensors have the potential to detect objects that are too small to be

Neutron activation analysis of high purity substances

International Nuclear Information System (INIS)

Gil'bert, Eh.N.

1987-01-01

Peculiarities of neutron-activation analysis (NAA) of high purity substances are considered. Simultaneous determination of a wide series of elements, high sensitivity (the lower bound of determined contents 10 -9 -10 -10 %), high selectivity and accuracy (Sr=0.10-0.15, and may be decreased up to 0.001), possibility of analysis of the samples from several micrograms to hundreds of grams, simplicity of calibration may be thought NAA advantages. Questions of accounting of NAA systematic errors associated with the neutron flux screening by the analysed matrix and with production of radionuclides of determined elements from accompanying elements according to concurrent nuclear reactions, as well as accounting of errors due to self-absorption of recorded radiation by compact samples, are considered

Biexciton dephasing in a semiconductor microcavity

DEFF Research Database (Denmark)

Borri, P.; Langbein, W.; Woggon, U.

2001-01-01

the heavy-hole (HH) vacuum Rabi splitting is 3.6 meV, more than three times larger than the biexciton binding energy in the bare QW (1.1 meV). Due to the narrow linewidth of the polariton resonances, a well-resolved pump-induced optical absorption associated with biexcitons was observed. In this work we...

Ultranarrow polaritons in a semiconductor microcavity

DEFF Research Database (Denmark)

Jensen, Jacob Riis; Borri, Paola; Langbein, Wolfgang

2000-01-01

We have achieved a record high ratio (19) of the Rabi splitting (3.6 meV) to the polariton linewidth (190 mu eV), in a semiconductor lambda microcavity with a single 25 nm GaAs quantum well at the antinode. The narrow polariton lines are obtained with a special cavity design which reduces...

Megawatt dye laser oscillator-amplifier system for high resolution spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Drell, P; Chu, S

1979-03-01

Peak powers in excess of 4 MW in the visible and 1.3 MW in the uv with linewidths as narrow as 80 MHz are generated with three YAG pumped amplifier stages following a cw dye oscillator. The laser pulses are nearly Fourier transform limited in frequency space and diffraction limited in coordinate space.

Preparation of High-purity Indium Oxalate Salt from Indium Scrap by Organic Acids

International Nuclear Information System (INIS)

Koo, Su-Jin; Ju, Chang-Sik

2013-01-01

Effect of organic acid on the preparation of indium-oxalate salt from indium scraps generated from ITO glass manufacturing process was studied. Effects of parameters, such as type and concentration of organic acids, pH of reactant, temperature, reaction time on indium-oxalate salt preparation were examined. The impurity removal efficiency was similar for both oxalic acid and citric acid, but citric acid did not make organic acid salt with indium. The optimum conditions were 1.5 M oxalic acid, pH 7, 80 .deg. C, and 6 hours. On the other hand, the recoveries increased with pH, but the purity decreased. The indium-oxalate salt purity prepared by two cycles was 99.995% (4N5). The indium-oxalate salt could be converted to indium oxide and indium metal by substitution reaction and calcination

Approaches to the accurate characterization of high purity metal fluorides and fluoride glasses

Science.gov (United States)

Beary, E. S.; Paulsen, P. J.; Rains, T. C.; Ewing, K. J.; Jaganathan, J.; Aggarwal, I.

1990-11-01

The analytical challenges posed by the measurement of trace contaminants in high purity metal fluorides require that innovative chemical preparation procedures be used to enhance existing instrumental techniques. The instrumental techniques used to analyze these difficult matrices must be sensitive enough to detect extremely low levels of trace impurities, and the background interferences derived from the matrix (metal fluoride or glass) must be minimized. A survey of analytical techniques that have the necessary characteristics to analyze these materials will be given. In addition, means of controlling the chemical blank will be presented. Mass and atomic spectrometric techniques will be discussed, specifically graphite furnace atomic absorption spectrometry (GFAAS) and inductively coupled plasma-mass spectrometry (ICP-MS). Analytical procedures using GFAAS and ICP-MS have been developed to determine sub ppb (part per billion) levels of contaminants in high purity fluoride materials.

The investigation of ferromagnetic resonance linewidth in Ni{sub 80}Fe{sub 20} films with submicron rectangular elements

Energy Technology Data Exchange (ETDEWEB)

Zhang, D. [Department of Physics, Southeast University, Nanjing, 211189 (China); School of Physical Science and Information Engineering, Liaocheng University, Liaocheng, 252059 (China); Yue, J. J.; Kou, Z. X.; Lin, L. [Department of Physics, Southeast University, Nanjing, 211189 (China); Zhai, Y., E-mail: yazhai@seu.edu.cn [Department of Physics, Southeast University, Nanjing, 211189 (China); National Laboratory of Solid Microstructures, Nanjing University, Nanjing, 210093 (China); Zhai, H. R. [National Laboratory of Solid Microstructures, Nanjing University, Nanjing, 210093 (China)

2016-05-15

Patterned magnetic films with nano-scaled dots exhibit some special magnetic properties. In this paper, we investigate the in-plane shape anisotropy and the magnetization dynamic damping in permalloy (Ni{sub 80}Fe{sub 20}) arrays of submicron rectangular elements using ferromagnetic resonance (FMR). The FMR linewidth exhibits a dependence on the element size, and mainly comes from the contribution of the intrinsic damping. Also the contribution of two-magnon scattering plays an important role and is reduced with increasing aspect ratio. The damping coefficient decreases from 0.0129 to 0.0118 with the element length increasing from 300 nm to 1200 nm, and the theoretical calculation suggests that the change of damping results from the longitudinal and transverse interlayer spin current due to the spatially inhomogeneous magnetization dynamics.

Pool Boiling CHF in Inclined Narrow Annuli

International Nuclear Information System (INIS)

Kang, Myeong Gie

2010-01-01

Pool boiling heat transfer has been studied extensively since it is frequently encountered in various heat transfer equipment. Recently, it has been widely investigated in nuclear power plants for application to the advanced light water reactors designs. Through the review on the published results it can be concluded that knowledge on the combined effects of the surface orientation and a confined space on pool boiling heat transfer is of great practical importance and also of great academic interest. Fujita et al. investigated pool boiling heat transfer, from boiling inception to the critical heat flux (CHF, q' CHF ), in a confined narrow space between heated and unheated parallel rectangular plates. They identified that both the confined space and the surface orientation changed heat transfer much. Kim and Suh changed the surface orientation angles of a downward heating rectangular channel having a narrow gap from the downward-facing position (180 .deg.) to the vertical position (90 .deg.). They observed that the CHF generally decreased as the inclination angle (θ ) increased. Yao and Chang studied pool boiling heat transfer in a confined heat transfer for vertical narrow annuli with closed bottoms. They observed that when the gap size ( s ) of the annulus was decreased the effect of space confinement to boiling heat transfer increased. The CHF was occurred at much lower value for the confined space comparing to the unconfined pool boiling. Pool boiling heat transfer in narrow horizontal annular crevices was studied by Hung and Yao. They concluded that the CHF decreased with decreasing gap size of the annuli and described the importance of the thin film evaporation to explain the lower CHF of narrow crevices. The effect of the inclination angle on the CHF on countercurrent boiling in an inclined uniformly heated tube with closed bottoms was also studied by Liu et al. They concluded that the CHF reduced with the inclination angle decrease. A study was carried out

Narrow-Band Imaging: Clinical Application in Gastrointestinal Endoscopy

Directory of Open Access Journals (Sweden)

Sandra Barbeiro

2018-03-01

Full Text Available Narrow-band imaging is an advanced imaging system that applies optic digital methods to enhance endoscopic images and improves visualization of the mucosal surface architecture and microvascular pattern. Narrow-band imaging use has been suggested to be an important adjunctive tool to white-light endoscopy to improve the detection of lesions in the digestive tract. Importantly, it also allows the distinction between benign and malignant lesions, targeting biopsies, prediction of the risk of invasive cancer, delimitation of resection margins, and identification of residual neoplasia in a scar. Thus, in expert hands it is a useful tool that enables the physician to decide on the best treatment (endoscopic or surgical and management. Current evidence suggests that it should be used routinely for patients at increased risk for digestive neoplastic lesions and could become the standard of care in the near future, at least in referral centers. However, adequate training programs to promote the implementation of narrow-band imaging in daily clinical practice are needed. In this review, we summarize the current scientific evidence on the clinical usefulness of narrow-band imaging in the diagnosis and characterization of digestive tract lesions/cancers and describe the available classification systems.

Improved color metrics in solid-state lighting via utilization of on-chip quantum dots

Science.gov (United States)

Mangum, Benjamin D.; Landes, Tiemo S.; Theobald, Brian R.; Kurtin, Juanita N.

2017-02-01

While Quantum Dots (QDs) have found commercial success in display applications, there are currently no widely available solid state lighting products making use of QD nanotechnology. In order to have real-world success in today's lighting market, QDs must be capable of being placed in on-chip configurations, as remote phosphor configurations are typically much more expensive. Here we demonstrate solid-state lighting devices made with on-chip QDs. These devices show robust reliability under both dry and wet high stress conditions. High color quality lighting metrics can easily be achieved using these narrow, tunable QD downconverters: CRI values of Ra > 90 as well as R9 values > 80 are readily available when combining QDs with green phosphors. Furthermore, we show that QDs afford a 15% increase in overall efficiency compared to traditional phosphor downconverted SSL devices. The fundamental limit of QD linewidth is examined through single particle QD emission studies. Using standard Cd-based QD synthesis, it is found that single particle linewidths of 20 nm FWHM represent a lower limit to the narrowness of QD emission in the near term.

MOVPE grown InGaAs quantum dots of high optical quality as seed layer for low-density InP quantum dots

International Nuclear Information System (INIS)

Richter, D; Hafenbrak, R; Joens, K D; Schulz, W-M; Eichfelder, M; Rossbach, R; Jetter, M; Michler, P

2010-01-01

To achieve a low density of optically active InP-quantum dots we used InGaAs islands embedded in GaAs as a seed layer. First, the structural InGaAs quantum dot properties and the influence of the annealing technique was investigated by atomic force microscope measurements. High-resolution micro-photoluminescence spectra reveal narrow photoluminescence lines, with linewidths down to 11 μeV and fine structure splittings of 25 μeV. Furthermore, using these InGaAs quantum dots as seed layer reduces the InP quantum dot density of optically active quantum dots drastically. InP quantum dot excitonic photoluminescence emission with a linewidth of 140 μeV has been observed.

Purity Assessment of Organic Reference Materials with a Mass Balance Method: A Case Study of Endosulfan-II

International Nuclear Information System (INIS)

Kim, Seunghyun; Lee, Joonhee; Ahn, Seonghee; Song, Youngsin; Kim, Dongkyun; Kim, Byungjoo

2013-01-01

A mass balance method established in this laboratory was applied to determine the purity of an endosulfan-II pure substance. Gas chromatography-flame ionization detector (GC-FID) was used to measure organic impurities. Total of 10 structurally related organic impurities were detected by GC-FID in the material. Water content was determined to be 0.187% by Karl-Fischer (K-F) coulometry with an oven-drying method. Nonvolatile residual impurities was not detected by Thermal gravimetric analysis (TGA) within the detection limit of 0.04% (0.7 μg in absolute amount). Residual solvents within the substance were determined to be 0.007% in the Endosulfan-II pure substance by running GC-FID after dissolving it with two solvents. The purity of the endosulfan-II was finally assigned to be (99.17 ± 0.14)%. Details of the mass balance method including interpretation and evaluating uncertainties of results from each individual methods and the finally assayed purity were also described

Quantum Logic with Cavity Photons From Single Atoms.

Science.gov (United States)

Holleczek, Annemarie; Barter, Oliver; Rubenok, Allison; Dilley, Jerome; Nisbet-Jones, Peter B R; Langfahl-Klabes, Gunnar; Marshall, Graham D; Sparrow, Chris; O'Brien, Jeremy L; Poulios, Konstantinos; Kuhn, Axel; Matthews, Jonathan C F

2016-07-08

We demonstrate quantum logic using narrow linewidth photons that are produced with an a priori nonprobabilistic scheme from a single ^{87}Rb atom strongly coupled to a high-finesse cavity. We use a controlled-not gate integrated into a photonic chip to entangle these photons, and we observe nonclassical correlations between photon detection events separated by periods exceeding the travel time across the chip by 3 orders of magnitude. This enables quantum technology that will use the properties of both narrow-band single photon sources and integrated quantum photonics.

Angular-dependent EDMR linewidth for spin-dependent space charge limited conduction in a polycrystalline pentacene

Science.gov (United States)

Fukuda, Kunito; Asakawa, Naoki

2017-08-01

Spin-dependent space charge limited carrier conduction in a Schottky barrier diode using polycrystalline p-type π-conjugated molecular pentacene is explored using multiple-frequency electrically detected magnetic resonance (EDMR) spectroscopy with a variable-angle configuration. The measured EDMR spectra are decomposed into two components derived respectively from mobile and trapped positive polarons. The linewidth of the EDMR signal for the trapped polarons increases with increasing resonance magnetic field for an in-plane configuration where the normal vector of the device substrate is perpendicular to the resonance magnetic field, while it is independent of the field for an out-of-plane configuration. This difference is consistent with the pentacene arrangement on the device substrate, where pentacene molecules exhibit a uniaxial orientation on the out-of-substrate plane. By contrast, the mobile polarons do not show anisotropic behavior with respect to the resonance magnetic field, indicating that the anisotropic effect is averaged out owing to carrier motion. These results suggest that the orientational arrangements of polycrystalline pentacene molecules in a nano thin film play a crucial role in spin-dependent electrical conduction.

TIGRESS highly-segmented high-purity germanium clover detector

Science.gov (United States)

Scraggs, H. C.; Pearson, C. J.; Hackman, G.; Smith, M. B.; Austin, R. A. E.; Ball, G. C.; Boston, A. J.; Bricault, P.; Chakrawarthy, R. S.; Churchman, R.; Cowan, N.; Cronkhite, G.; Cunningham, E. S.; Drake, T. E.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hyland, B.; Jones, B.; Leslie, J. R.; Martin, J.-P.; Morris, D.; Morton, A. C.; Phillips, A. A.; Sarazin, F.; Schumaker, M. A.; Svensson, C. E.; Valiente-Dobón, J. J.; Waddington, J. C.; Watters, L. M.; Zimmerman, L.

2005-05-01

The TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer (TIGRESS) will consist of twelve units of four high-purity germanium (HPGe) crystals in a common cryostat. The outer contacts of each crystal will be divided into four quadrants and two lateral segments for a total of eight outer contacts. The performance of a prototype HPGe four-crystal unit has been investigated. Integrated noise spectra for all contacts were measured. Energy resolutions, relative efficiencies for both individual crystals and for the entire unit, and peak-to-total ratios were measured with point-like sources. Position-dependent performance was measured by moving a collimated source across the face of the detector.

Effect of zirconium purity on the glass-forming-ability and notch toughness of Cu{sub 43}Zr{sub 43}Al{sub 7}Be{sub 7}

Energy Technology Data Exchange (ETDEWEB)

Andersen, Laura M. [Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA (United States); Hofmann, Douglas C. [Materials Development and Manufacturing Technology Group, NASA Jet Propulsion Laboratory/California Institute of Technology, MS 18-105, 4800 Oak Grove Dr. Pasadena, CA 91109 (United States); Vecchio, Kenneth S., E-mail: kvecchio@ucsd.edu [Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA (United States)

2016-09-30

The effect of substituting standard grade zirconium lump (99.8% excluding up to 4% hafnium) for high purity zirconium crystal bar (99.5%) in a Cu{sub 43}Zr{sub 43}Al{sub 7}Be{sub 7} bulk metallic glass (BMG) is examined. The final hafnium content in the BMG specimens was found to range from 0 to 0.44 at%. Introducing low purity zirconium significantly decreased the glass-forming-ability and reduced the notch toughness of the BMG. In contrast, when adding high purity hafnium to Cu{sub 43}Zr{sub 43}Al{sub 7}Be{sub 7} made with high purity zirconium, no significant change in the glass-forming-ability or toughness was observed. This suggests that the introduction of low purity zirconium in BMGs creates a more complex response than a simple addition of hafnium. It is likely that other impurities in the material, such as oxygen, play a role in the complex crystallization kinetics and change in mechanical properties. The notch toughness was measured through four-point-bend tests, which showed a decrease in notch toughness from an average of ~53 MPa m{sup 1/2} for the high purity samples to an average of ~29 MPa m{sup 1/2} with full substitution of low purity zirconium. A similar decrease in glass-forming-ability and toughness is observed in commercially synthesized high purity Cu{sub 43}Zr{sub 43}Al{sub 7}Be{sub 7}. The large scale commercial process is expected to introduced some unintentional impurities, which decrease the properties of the BMG in the same way as the lower purity elements. Lastly, Weibull statistics are used to provide an analysis of variability in toughness for both ingots synthesized in a small laboratory arc-melter and those synthesized commercially.

Initial Stages of Recrystallization in Aluminum of Commercial Purity

DEFF Research Database (Denmark)

Hansen, Niels; Bay, Bent

1979-01-01

In commercial aluminum with a purity of 99.4 pct, the formation and growth of recrystallization nuclei were studied by techniques such asin-situ annealing in a high voltage electron microscope, transmission electron microscopy and light microscopy. Sample parameters were the initial grain size (370...... by the FeAl3 particles present in the commercial aluminum as impurities. The nucleation temperatures determined by high voltage electron microscopy and transmission electron microscopy decrease markedly when the initial grain size is decreased both after 50 and 90 pct cold rolling; a less pronounced...

Release characteristics of tritium from high-purity lithium oxide

International Nuclear Information System (INIS)

O'Kula, K.R.; Vogelsang, W.F.

1985-01-01

Rates of tritium release from neutronirradiated lithium oxide were determined from isothermal release experiments. High-purity, monocrystalline lithium oxide was purged ex-reactor with helium and helium-hydrogen gas streams. Overall release was found to be controlled by solid-phase diffusion, and was predominantly in the form of condensible species. The result of an independent concentration profile analysis at 923 K was in agreement with the gas release diffusion coefficient. Sweeping the Li 2 O with hydrogen-containing gas was found to enhance tritium removal during the early stage of each run

In vitro characterization of high purity factor IX concentrates for the treatment of hemophilia B.

Science.gov (United States)

Limentani, S A; Gowell, K P; Deitcher, S R

1995-04-01

This study employed sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis and immunoblotting to assess the purity of seven high purity factor IX concentrates: Aimafix (Aima), AlphaNine-SD (Alpha Therapeutic), Factor IX VHP (Biotransfusion), Immunine (Immuno), Mononine (Armour Pharmaceutical), Nanotiv (Kabi Pharmacia), and 9MC (Blood Products Laboratory). The mean specific activity of these products ranged from 68 U factor IX/mg (Aimafix) to 246 U factor IX/mg (Mononine). SDS-PAGE analysis showed that the highest purity product, Mononine, had a single contaminating band under non-reducing conditions. Two additional bands were detected when this product was analyzed under reducing conditions. All other products had multiple contaminating bands that were more apparent under reducing than non-reducing conditions. The immunoblot for factor IX showed a dominant factor IX band for all products. In addition, visible light chain of factor IX was detected for AlphaNine-SD, Factor IX VHP, Immunine, Mononine, Nanotiv, and 9MC, suggesting that the factor IX in these products had undergone partial activation to factor IXa. Another contaminating band was visible at 49,500 for all of the products except 9MC. In addition to this band, high molecular weight contaminants were apparent for some products, most notably AlphaNine-SD. The identity of these bands is unknown. Immunoblotting failed to demonstrate factor VII as a contaminant of any of the high purity products, although factor VIIa could be detected in some lots of Immunine, Nanotiv, and 9MC by a clot-based assay. Factor X contaminated Aimafix, AlphaNine-SD, Factor IX VHP, Immunine, Nanotiv, and 9MC, but activation products of factor X were not detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of the radiochemical purity of phosphorus-32 and tritium-labeled diisopropylphosphorofluoridate (DFP)

International Nuclear Information System (INIS)

Christopher, R.E.; Sheppard, G.

1975-01-01

A method is described for the determination of the radiochemical purity of labeled diisopropylphosphorofluoridate (DFP), based on the irreversible inhibition reaction with the enzyme α-chymotrypsin. The nature of the impurities in commercially available 32 P- and 3 H-labeled DFP is discussed

Influence of purity level on the mechanical properties of hot isostatically pressed beryllium

International Nuclear Information System (INIS)

Odegard, B.C. Jr.

1979-09-01

The procurement of a quantity of ultra-pure beryllium powder combined with special handling from powder to billet form resulted in the fabrication of high purity beryllium. The mechanical properties of these billets were contrasted to those of commercial grade billets to determine the influence of impurities and powder processing. The tensile test results show that the strength values are primarily dependent on the grain size in a behavior predictable by the Hall-Petch relationship. Only a fraction of the strength differential can be attributed to metallic impurities in solution. The grain size is controlled by the powder size distribution. The ductility is dominated by both grain size and oxide content. The fine grained, low oxide billets exhibited the highest ductilities. There is evidence to suggest that oxide distribution has a large influence on the ductility. The fracture toughness was highest for the high purity beryllium billets

Tests of ball bearing used in high-temperature and high-purity water

International Nuclear Information System (INIS)

Leng Chengmu; Hao Shouxin.

1987-01-01

According to the particular conditions and the operation environments in high-temperature and high-purity water, the test content and the measurement instrumentation for the ball bearing were defined. Through various tests, operational performances of the bearing have preliminarily been understood. It provided some useful information for the engineering application of the bearing

High purity and semi-insulating 4H-SiC crystals grown by physical vapor transport

Energy Technology Data Exchange (ETDEWEB)

Augustine, G.; Hobgood, H.McD.; Balakrishna, V.; Dunne, G.T.; Hopkins, R.H.; Thomas, R.N. [Northrop Grumman Corp., Pittsburgh, PA (United States). Science and Technology Center; Doolittle, W.A.; Rohatgi, A. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Electrical and Computer Engineering

1998-06-01

High purity undoped and semi-insulating vanadium doped 4H-SiC single crystals with diameters up to 50 mm were grown by the physical vapor transport method. Undoped crystals exhibiting resistivities in the 10{sup 2} to 10{sup 3} {Omega}-cm range and photoconductive decay (PCD) lifetimes in the 2 to 9 {mu}s range, were grown from high purity SiC sublimation sources. The crystals were p-type due to the presence of residual acceptor impurities, mainly boron. The semi-insulating behavior of the vanadium doped crystals is attributed to compensation of residual acceptors by the deep level vanadium donor located near the middle of the band gap. (orig.) 6 refs.

Bumblebees (Bombus terrestris) and honeybees (Apis mellifera) prefer similar colours of higher spectral purity over trained colours.

Science.gov (United States)

Rohde, Katja; Papiorek, Sarah; Lunau, Klaus

2013-03-01

Differences in the concentration of pigments as well as their composition and spatial arrangement cause intraspecific variation in the spectral signature of flowers. Known colour preferences and requirements for flower-constant foraging bees predict different responses to colour variability. In experimental settings, we simulated small variations of unicoloured petals and variations in the spatial arrangement of colours within tricoloured petals using artificial flowers and studied their impact on the colour choices of bumblebees and honeybees. Workers were trained to artificial flowers of a given colour and then given the simultaneous choice between three test colours: either the training colour, one colour of lower and one of higher spectral purity, or the training colour, one colour of lower and one of higher dominant wavelength; in all cases the perceptual contrast between the training colour and the additional test colours was similarly small. Bees preferred artificial test flowers which resembled the training colour with the exception that they preferred test colours with higher spectral purity over trained colours. Testing the behaviour of bees at artificial flowers displaying a centripetal or centrifugal arrangement of three equally sized colours with small differences in spectral purity, bees did not prefer any type of artificial flowers, but preferentially choose the most spectrally pure area for the first antenna contact at both types of artificial flowers. Our results indicate that innate preferences for flower colours of high spectral purity in pollinators might exert selective pressure on the evolution of flower colours.

New vacancy source in ultrahigh-purity aluminium single crystals with a low dislocation density

Energy Technology Data Exchange (ETDEWEB)

Mizuno, Kaoru; Yamamoto, Satoshi [Shimane Univ., Faculty of Science and Engineering, Matsue, Shimane (Japan); Morikawa, Kimihiko [Hokkaido Univ., Institute for Low Temperature Science, Sapporo, Hokkaido (Japan); Kuga, Masanori [Kanazawa Univ., Faculty of Science, Kanazawa, Ishikawa (Japan); Okamoto, Hiroyuki [Kanazawa Univ., Faculty of Medicine, Kanazawa, Ishikawa (Japan); Hashimoto, Eiji [Hiroshima Univ., Hiroshima Synchrotron Radiation Center, Higashi-Hiroshima, Hiroshima (Japan)

2004-05-01

The vacancy generation process in ultrahigh-purity aluminum single crystals with a low dislocation density was investigated by synchrotron radiation topography using a white X-ray beam. Some straight lines were observed in the topographys taken after temperature rose to 300degC from room temperature, and they were confirmed to be rows of successive small interstitial-type dislocation loops grown as vacancy sources. It was concluded that the thermal generation mechanism of vacancies in ultrahigh-purity aluminum single crystals with a low dislocation density consists of the following two steps. First, small interstitial loops are heterogeneously formed in the crystal lattice; second, these convert to lengthened loops with the development of screw components and finally grow into rows of dislocation loops emitting vacancies into the lattice. (author)

New vacancy source in ultrahigh-purity aluminium single crystals with a low dislocation density

International Nuclear Information System (INIS)

Mizuno, Kaoru; Yamamoto, Satoshi; Morikawa, Kimihiko; Kuga, Masanori; Okamoto, Hiroyuki; Hashimoto, Eiji

2004-01-01

The vacancy generation process in ultrahigh-purity aluminum single crystals with a low dislocation density was investigated by synchrotron radiation topography using a white X-ray beam. Some straight lines were observed in the topographys taken after temperature rose to 300degC from room temperature, and they were confirmed to be rows of successive small interstitial-type dislocation loops grown as vacancy sources. It was concluded that the thermal generation mechanism of vacancies in ultrahigh-purity aluminum single crystals with a low dislocation density consists of the following two steps. First, small interstitial loops are heterogeneously formed in the crystal lattice; second, these convert to lengthened loops with the development of screw components and finally grow into rows of dislocation loops emitting vacancies into the lattice. (author)

Comparison of Deformation in High-Purity Single/Large Grain and Polycrystalline Niobium Superconducting Cavities

International Nuclear Information System (INIS)

Ganapati Rao Myneni; Peter Kneisel

2005-01-01

The current approach for the fabrication of superconducting radio frequency (SRF) cavities is to roll and deep draw sheets of polycrystalline high-purity niobium. Recently, a new technique was developed at Jefferson Laboratory that enables the fabrication of single-crystal high-purity Nb SRF cavities. To better understand the differences between SRF cavities fabricated out of fine-grained polycrystalline sheet in the standard manner and single crystal cavities fabricated by the new technique, two half-cells were produced according to the two different procedures and compared using a variety of analytical techniques including optical microscopy, scanning laser confocal microscopy, profilometry, and X-ray diffraction. Crystallographic orientations, texture, and residual stresses were determined in the samples before and after forming and this poster presents the results of this ongoing study

Fashion Brand Purity and Firm Performance

Directory of Open Access Journals (Sweden)

Jin-hui Zheng

2013-01-01

Full Text Available A large number of prior empirical research and case studies used qualitative methodology to discuss the fashion brand dilution resulting from consumer base extension from the target group(s to the nontarget groups and its impacts. From a different perspective, this paper establishes a dynamic brand dilution and performance model, demonstrating how dynamic changes of sales volumes involving the two consumer groups affect the degree of brand dilution and the performance of the brand. We incorporate the factor “brand purity” to the model as a quantitative measure of brand dilution level that affects firm annual revenue and profit change comprehensively in iteration. Our model suggests that fashion brands, especially luxury brands, can be easily diluted under the pressure of firm growth, and the brands suffer the significant negative impact on their revenues and profit. While increasing sales volume can aggravate the negative consequences, brand purity can be increased through limiting the consumer base to the target group only.

The Effect of Divided Attention on Emotion-Induced Memory Narrowing

Science.gov (United States)

Steinmetz, Katherine R. Mickley; Waring, Jill D.; Kensinger, Elizabeth A.

2014-01-01

Individuals are more likely to remember emotional than neutral information, but this benefit does not always extend to the surrounding background information. This memory narrowing is theorized to be linked to the availability of attentional resources at encoding. In contrast to the predictions of this theoretical account, altering participants’ attentional resources at encoding, by dividing attention, did not affect the emotion-induced memory narrowing. Attention was divided using three separate manipulations: a digit ordering task (Experiment 1), an arithmetic task (Experiment 2), and an auditory discrimination task (Experiment 3). Across all three experiments, divided attention decreased memory across-the-board but did not affect the degree of memory narrowing. These findings suggest that theories to explain memory narrowing must be expanded to include other potential mechanisms beyond limitations of attentional resources. PMID:24295041

The effect of divided attention on emotion-induced memory narrowing.

Science.gov (United States)

Mickley Steinmetz, Katherine R; Waring, Jill D; Kensinger, Elizabeth A

2014-01-01

Individuals are more likely to remember emotional than neutral information, but this benefit does not always extend to the surrounding background information. This memory narrowing is theorised to be linked to the availability of attentional resources at encoding. In contrast to the predictions of this theoretical account, altering participants' attentional resources at encoding by dividing attention did not affect emotion-induced memory narrowing. Attention was divided using three separate manipulations: a digit ordering task (Experiment 1), an arithmetic task (Experiment 2) and an auditory discrimination task (Experiment 3). Across all three experiments, divided attention decreased memory across the board but did not affect the degree of memory narrowing. These findings suggest that theories to explain memory narrowing must be expanded to include other potential mechanisms beyond the limitations of attentional resources.

Bayesian Face Recognition and Perceptual Narrowing in Face-Space

Science.gov (United States)

Balas, Benjamin

2012-01-01

During the first year of life, infants' face recognition abilities are subject to "perceptual narrowing", the end result of which is that observers lose the ability to distinguish previously discriminable faces (e.g. other-race faces) from one another. Perceptual narrowing has been reported for faces of different species and different races, in…

Natural Convective Heat Transfer from Narrow Plates

CERN Document Server

Oosthuizen, Patrick H

2013-01-01

Natural Convective Heat Transfer from Narrow Plates deals with a heat transfer situation that is of significant practical importance but which is not adequately dealt with in any existing textbooks or in any widely available review papers. The aim of the book is to introduce the reader to recent studies of natural convection from narrow plates including the effects of plate edge conditions, plate inclination, thermal conditions at the plate surface and interaction of the flows over adjacent plates. Both numerical and experimental studies are discussed and correlation equations based on the results of these studies are reviewed.

Deuterium permeation and diffusion in high-purity beryllium

International Nuclear Information System (INIS)

Abramov, E.; Riehm, M.P.; Thompson, D.A.; Smeltzer, W.W.

1990-01-01

The permeation rate of deuterium through high-purity beryllium membranes was measured using the gas-driven permeation technique. The time-dependent and the steady-state deuterium flux data were analyzed and the effective diffusivities of the samples were determined. Using multilayer permeation theory the effects of surface oxide were eliminated and the diffusion coefficients of the bulk beryllium determined. The diffusion parameters obtained for the extra-grade beryllium samples (99.8%) are D 0 =6.7x10 -9 m 2 /s and E D =28.4 kJ/mol. For the high-grade beryllium samples (99%) the parameters are D 0 =8.0x10 -9 m 2 /s and E D =35.1 kJ/mol. (orig.)

Methods to improve and understand the sensitivity of high purity germanium detectors for searches of rare events

International Nuclear Information System (INIS)

Volynets, Oleksandr

2012-01-01

Observation of neutrinoless double beta-decay could answer fundamental questions on the nature of neutrinos. High purity germanium detectors are well suited to search for this rare process in germanium. Successful operation of such experiments requires a good understanding of the detectors and the sources of background. Possible background sources not considered before in the presently running GERDA high purity germanium detector experiment were studied. Pulse shape analysis using artificial neural networks was used to distinguish between signal-like and background-like events. Pulse shape simulation was used to investigate systematic effects influencing the efficiency of the method. Possibilities to localize the origin of unwanted radiation using Compton back-tracking in a granular detector system were examined. Systematic effects in high purity germanium detectors influencing their performance have been further investigated using segmented detectors. The behavior of the detector response at different operational temperatures was studied. The anisotropy effects due to the crystallographic structure of germanium were facilitated in a novel way to determine the orientation of the crystallographic axes.

Methods to improve and understand the sensitivity of high purity germanium detectors for searches of rare events

Energy Technology Data Exchange (ETDEWEB)

Volynets, Oleksandr

2012-07-27

Observation of neutrinoless double beta-decay could answer fundamental questions on the nature of neutrinos. High purity germanium detectors are well suited to search for this rare process in germanium. Successful operation of such experiments requires a good understanding of the detectors and the sources of background. Possible background sources not considered before in the presently running GERDA high purity germanium detector experiment were studied. Pulse shape analysis using artificial neural networks was used to distinguish between signal-like and background-like events. Pulse shape simulation was used to investigate systematic effects influencing the efficiency of the method. Possibilities to localize the origin of unwanted radiation using Compton back-tracking in a granular detector system were examined. Systematic effects in high purity germanium detectors influencing their performance have been further investigated using segmented detectors. The behavior of the detector response at different operational temperatures was studied. The anisotropy effects due to the crystallographic structure of germanium were facilitated in a novel way to determine the orientation of the crystallographic axes.

Process for producing high purity isoolefins and dimers thereof by dissociation of ethers

Science.gov (United States)

Smith, L.A. Jr.; Jones, E.M. Jr.; Hearn, D.

1984-05-08

Alkyl tertiary butyl ether or alkyl tertiary amyl ether is dissociated by vapor phase contact with a cation acidic exchange resin at temperatures in the range of 150 to 250 F at LHSV of 0.1 to 20 to produce a stream consisting of unreacted ether, isobutene or isoamylene and an alcohol corresponding to the alkyl radical. After the alcohol is removed, the ether/isoolefin stream may be fractionated to obtain a high purity isoolefin (99+%) or the ether/isoolefin stream can be contacted in liquid phase with a cation acidic exchange resin to selectively dimerize the isoolefin in a highly exothermic reaction, followed by fractionation of the dimerization product to produce high purity diisoolefin (97+%). In the case where the alkyl is C[sub 3] to C[sub 6] and the corresponding alcohol is produced on dissociation of the ether, combined dissociation-distillation may be carried out such that isoolefin is the overhead product and alcohol the bottom. 2 figs.

Supply-side response to declining heroin purity: fentanyl overdose episode in New Jersey.

Science.gov (United States)

Hempstead, Katherine; Yildirim, Emel O

2014-06-01

The inelastic price demand observations characteristic of illegal drug markets have led to the conclusion that the burden of a negative supply shock would be completely reflected to consumers. This paper argues that the increasing availability of prescription opioids may threaten heroin sellers' profit margin and force them to find alternative methods to compensate buyers in the event of a supply shock. We investigate the 2006 fentanyl overdose episode in New Jersey and argue that the introduction of non-pharmaceutical fentanyl, its spatial distribution, and the timing of overdose deaths may have been related to trends in heroin purity. Using medical examiner data, as well as data from the Drug Enforcement Administration, Office of Diversion Control on retail sales of prescription opioids in a negative binomial specification, we show that month-to-month fluctuations in heroin purity have a significant effect on fentanyl-related overdoses, particularly in those areas where prescription opioids are highly available. Copyright © 2013 John Wiley & Sons, Ltd.

Rare earth impurities in high purity lanthanum oxide determined by neutron activation analysis

International Nuclear Information System (INIS)

Nguyen Van Suc; Desai, H.B.; Parthasarathy, R.; Gangadharan, S.

1992-01-01

Individual rare earth impurities in high purity La 2 O 3 (≥99.9%) have been determined by NAA after pre-separation of the matrix (La). The separation is carried out on an anion exchanger (Dowex 1x8) using different mixtures of methanol/nitric acid as eluants. The rare earth elements from Dy to Lu are eluted quantitatively using a 10% 1M HNO 3 - 90% methanol mixture, while the light rare earths from Ce to Gd are eluted quantitatively using a 10% 0.05M HNO 3 - 90% methanol mixture. La, which is retained on the column, is eluted using 0.1M HNO 3 . The recoveries of the various rare earth elements have been checked using radiotracers and also by spiking the sample with known amount of elements, and the recoveries are found to be quantitative. Results obtained on a typical high purity lanthanum oxide are reported here. (author) 5 refs.; 1 fig

Preparation of High Purity CdTe for Nuclear Detector: Electrical and Nuclear Characterization

Science.gov (United States)

Zaiour, A.; Ayoub, M.; Hamié, A.; Fawaz, A.; Hage-ali, M.

High purity crystal with controllable electrical properties, however, control of the electrical properties of CdTe has not yet been fully achieved. Using the refined Cd and Te as starting materials, extremely high-purity CdTe single crystals were prepared by the traditional vertical THM. The nature of the defects involved in the transitions was studied by analyzing the position of the energy levels by TSC method. The resolution of 4.2 keV (FWHM) confirms the high quality and stability of the detectors: TSC spectrum was in coherence with detectors spectrum with a horizontal plate between 0.2 and 0.6 eV. The enhancement in resolution of detectors with a full width at half- maximum (less than 0.31 meV), lead to confirm that the combination of vacuum distillation and zone refining was very effective to obtain more purified CdTe single crystals for photovoltaic or nuclear detectors with better physical properties.

Are narrow mesons, baryons and dibaryons evidence for multiquark states?

International Nuclear Information System (INIS)

Tatischeff, B.; Yonnet, J.

2000-01-01

Several narrow structures have been progressively observed since the last fifteen years, in di-baryonic invariant mass spectra or in missing mass spectra. More recently, narrow structures were observed in baryonic and now in mesonic mass spectra. Since these small peaks appear at fixed masses, independently of the experiment, they are associated with real states. There is no room to explain these states within classical nuclear physics taking into account baryonic and mesonic degrees of freedom. An interpretation is proposed, which associate these narrow structures with two coloured quark clusters. (authors)

Amplitude dependent damping in single crystalline high purity molybdenum

International Nuclear Information System (INIS)

Zelada-Lambri, G.I; Lambri, O.A; Garcia, J.A; Lomer, J.N

2004-01-01

Amplitude dependent damping measurements were performed on high purity single crystalline molybdenum at several different constant temperatures between room temperature and 1273K. The employed samples were single crystals with the orientation, having a residual resistivity ratio of about 8000. Previously to the amplitude dependent damping tests, the samples were subjected to different thermomechanical histories. Amplitude dependent damping effects appear only during the first heating run in temperature where the samples have the thermomechanical state of the deformation process at room temperature. In the subsequent run-ups in temperature, i.e, after subsequent annealings, amplitude dependent damping effects were not detected (au)

Improved procedure for high purity gaseous peroxyacyl nitrate production: use of heavy lipid solvents

Energy Technology Data Exchange (ETDEWEB)

Gaffney, J S; Fajer, R; Senum, G I

1984-01-01

An improved procedure is described for the production of peroxyacyl nitrates (PAN's) in the gas phase. The method of Nielsen et al. (1982) has been modified to yield PAN's of high purity with no further chromatographic purification required. Extraction of PAN's from the nitration of the peracids is accomplished by use of a heavy lipid solvent (n-tridecane). This solvent's low vapor pressure allows the simple separation and preparation of high purity gaseous PAN's (>98%) as determined by Fourier transform infrared spectroscopy (FTIR). Using this method infrared integrated band strengths are reported for peroxyacetyl nitrate (PAN) perdeutero-peroxyacetyl nitrate (PAN-D/sub 3/) and peroxyproprionyl nitrate (PPN). The method allows facile production of large amounts of gaseous PAN's for smog chamber and laboratory studies, toxicological and health effects research, as well as for calibration of PAN analyses.

The effect of the purity and of the materials used for adapters on the purification of yttrium by solid state electrotransport

International Nuclear Information System (INIS)

Nikoforova, T.V.; Volkov, V.T.

1986-01-01

The influence of tantalum, molybdenum and zirconium adapters on the efficiency of the solid state electrotransport process is investigated with a view to increasing the quality and purity of yttrium. The degree and direction of metallic impurity electromigration in the given metals were studied. The impurities in question were shown to move in different directions depending on the type of adapter. Recommendations for the application of adapters according to their purity are given. The application of high purity tantalum as anode and cathode adapters in three-stage solid state electrotransport enabled us to obtain yttrium single crystals with a ratio of resistance at room temperature to that at helium temperatures of 1200. (orig.)

What's in a name? Expiratory tracheal narrowing in adults explained

International Nuclear Information System (INIS)

Leong, P.; Bardin, P.G.; Lau, K.K.

2013-01-01

Tracheomalacia, tracheobronchomalacia, and excessive dynamic airway collapse are all terms used to describe tracheal narrowing in expiration. The first two describe luminal reduction from cartilage softening and the latter refers to luminal reduction from exaggerated posterior membrane movement. Expiratory tracheal narrowing is a frequent occurrence that can cause symptoms of airway obstruction, such as dyspnoea, wheeze, and exercise intolerance. The accurate diagnosis and quantification of expiratory tracheal narrowing has important aetiological, therapeutic, and prognostic implications. The reference standard for diagnosis has traditionally been bronchoscopy; however, this method has significant limitations. Expiratory tracheal disorders are readily detected by four-dimensional dynamic volume multidetector computed tomography (4D-CT), an emerging, non-invasive method that will potentially enable detection and quantification of these conditions. This review discusses the morphological forms of expiratory tracheal narrowing and demonstrates the utility of 4D-CT in the diagnosis, quantification, and treatment of these important conditions

Multilayer Photonic Crystal for Spectral Narrowing of Emission

Directory of Open Access Journals (Sweden)

Zhanfang LIU

2017-08-01

Full Text Available Multilayer colloidal crystal has been prepared by the layer-by-layer deposition of silica microspheres on a glass slide. Each layer is a slab consisting of a fcc close-packed colloidal arrays. By properly choosing the sizes of spheres, the whole spectral feature of multilayer colloidal crystal can be tuned. Here, we engineered a multilayer superlattice structure with an effective passband between two stop bands. This gives a strong narrowing effect on emission spectrum. With the stop bands at the shortwave and longwave edges of emission spectrum, the passband in the central wavelength region can be regarded as a strong decrease of suppression effect and enhancement of a narrow wavelength region of emission. The spectral narrowing modification effect of suitably engineered colloidal crystals shows up their importance in potential application as optical filters and lasing devices.DOI: http://dx.doi.org/10.5755/j01.ms.23.3.16320

Bandwidth-narrowed Bragg gratings inscribed in double-cladding fiber by femtosecond laser.

Science.gov (United States)

Shi, Jiawei; Li, Yuhua; Liu, Shuhui; Wang, Haiyan; Liu, Ningliang; Lu, Peixiang

2011-01-31

Bragg gratings with the bandwidth(FWHM) narrowed up to 79 pm were inscribed in double-cladding fiber with femtosecond radiation and a phase mask followed by an annealing treatment. With the annealing temperature below a critical value, the bandwidth of Bragg gratings induced by Type I-IR and Type II-IR index change was narrowed without the reduction of reflectivity. The bandwidth narrowing is due to the profile transformation of the refractive index modulation caused by the annealing treatment. This mechanism was verified by comparing bandwidth narrowing processes of FBGs written with different power densities.

Efficient 1.5-μm Raman generation in ethane-filled hollow-core fiber

Science.gov (United States)

Chen, Yubin; Gu, Bo; Wang, Zefeng; Lu, Qisheng

2016-11-01

We demonstrated for the first time a novel and effective method for obtaining both high peak-power and narrow linewidth 1.5 μm fiber sources through gas Raman effect in hollow core fibers. An Ethane-filled ice-cream antiresonance hollow-core fiber is pumped with a high peak-power pulse 1064 nm microchip laser, generating 1552.7 nm Stokes wave by pure vibrational stimulated Raman scattering of ethane molecules. A maximum peak-power of about 400 kW is achieved with 6 meter fiber length at 2 bar pressure, and the linewidth is about 6.3 GHz. The maximum Raman conversion efficiency of 1064 nm to 1552.7 nm is about 38%, and the corresponding laser slope efficiency is about 61.5%.

Broad band tunable dye laser development

International Nuclear Information System (INIS)

Lee, Jong Min; Kim, Jung Bog; Kim, Sung Ho; Go, Do Kyung; Lim, Chang Hwan; Rho, Si Pyo; Song, Kyu Seok; Lee, Byung Cheol; Rhi, Jong Hoon; Han, Jae Min; Cha, Hyung Ki; Cha, Byung Hun; Jeong, Do Yung; Han, Jae Min; Jung, Yeu Chang; Im, Ho; Yoo, Choon Sun; Jung, Byung Ik; Seok, Gum Sook

1992-12-01

The technical goal and objectives are the development of a tunable laser which can be tuned from UV to near IR and commercialization for uses in various fields. Two kinds of resonators are developed. User can select one resonator and change into the other without changing other parts. GIM type has a linewidth of 5GHz which is able to be used usually, and SLM type is very narrow linewidth of less than 1GHz. Each system can have one or two amplifiers depending on output power or cost. High stability and safety, cost-down, and modules into about 30 components have been tried. We hope that this laser can help developments in researches of university, industry, and institute. (Author)

RESEARCH ON MICROBIOLOGICAL PURITY OF “PHYTOPROST” AND “TAMSULOPROST” SUPPOSITORIES

Directory of Open Access Journals (Sweden)

Gritsenko V. I.

2014-01-01

Full Text Available Results of the tests on microbiological purity of the test samples of "Tamsuloprost" and "Phytoprost" suppositories for the treatment of prostate diseases have shown that no viable cells of fungi were found in the preparations, the number of viable cells of microorganisms is within a norman rate. Studying the effectiveness of antimicrobial preservatives it was found that the test samples meet criterion of the requirements of the State Pharmacopoeia of Ukraine.

Angular-Dependent EDMR Linewidth for Spin-Dependent Space-Charge-Limited Conduction in a Polycrystalline Pentacene

Directory of Open Access Journals (Sweden)

Kunito Fukuda

2017-08-01

Full Text Available Spin-dependent space-charge-limited carrier conduction in a Schottky barrier diode using polycrystalline p-type π-conjugated molecular pentacene is explored using multiple-frequency electrically detected magnetic resonance (EDMR spectroscopy with a variable-angle configuration. The measured EDMR spectra are decomposed into two components derived, respectively, from mobile and trapped positive polarons. The linewidth of the EDMR signal for the trapped polarons increases with increasing resonance magnetic field for an in-plane configuration where the normal vector of the device substrate is perpendicular to the resonance magnetic field, while it is independent of the field for an out-of-plane configuration. This difference is consistent with the pentacene arrangement on the device substrate, where pentacene molecules exhibit a uniaxial orientation on the out-of-substrate plane. By contrast, the mobile polarons do not show anisotropic behavior with respect to the resonance magnetic field, indicating that the anisotropic effect is averaged out owing to carrier motion. These results suggest that the orientational arrangements of polycrystalline pentacene molecules in a nano thin film play a crucial role in spin-dependent electrical conduction.

Large-scale synthesis of high-purity well-aligned carbon nanotubes using pyrolysis of iron(II) phthalocyanine and acetylene

Science.gov (United States)

Liu, B. C.; Lee, T. J.; Lee, S. H.; Park, C. Y.; Lee, C. J.

2003-08-01

Well-aligned carbon nanotubes (CNTs) with high purity have been produced by pyrolysis of iron(II) phthalocyanine and acetylene at 800 °C. The synthesized CNTs have a length of 75 μm and diameters ranging from 20 to 60 nm. The CNTs have a bamboo-like structure and exhibit good crystallinity of graphite sheets. The growth rate of the CNTs was rapidly increased with adding C 2H 2. Our results demonstrate that the proposed growth method is suitable to large-scale synthesis of high-purity well-aligned CNTs on various substrates.

Determination of Ergot Alkaloids: Purity and Stability Assessment of Standards and Optimization of Extraction Conditions for Cereal Samples

DEFF Research Database (Denmark)

Krska, R.; Berthiller, F.; Schuhmacher, R.

2008-01-01

as those that are the most common and physiologically active. The purity of the standards was investigated by means of liquid chromatography with diode array detection, electrospray ionization, and time-of-flight mass spectrometry (LC-DAD-ESI-TOF-MS). All of the standards assessed showed purity levels...... (PSA) before LC/MS/MS. Based on the results obtained from these optimization studies, a mixture of acetonitrile with ammonium carbonate buffer was used as extraction solvent, as recoveries for all analyzed ergot alkaloids were significantly higher than those with the other solvents. Different sample...

Human parvovirus B19 infection in hemophiliacs first infused with two high-purity, virally attenuated factor VIII concentrates.

Science.gov (United States)

Azzi, A; Ciappi, S; Zakvrzewska, K; Morfini, M; Mariani, G; Mannucci, P M

1992-03-01

Human parvovirus B19 can be transmitted by coagulation factor concentrates and is highly resistant to virucidal methods. To evaluate whether the additional removal of virus by chromatographic methods during the manufacture of high-purity concentrates reduces the risk of B19 transmission, we have prospectively evaluated the rate of anti-B19 seroconversion in two groups of susceptible (anti-B19 negative) hemophiliacs infused with high-purity, heated (pasteurized) or solvent-detergent-treated factor VIII concentrates. Both products infected a relatively high proportion of patients (nine of 20).

Recent developments in high purity niobium metal production at CBMM

International Nuclear Information System (INIS)

Abdo, Gustavo Giovanni Ribeiro; Sousa, Clovis Antonio de Faria; Guimarães, Rogério Contato; Ribas, Rogério Marques; Vieira, Alaércio Salvador Martins; Menezes, Andréia Duarte; Fridman, Daniel Pallos; Cruz, Edmundo Burgos

2015-01-01

CBMM is a global supplier of high quality niobium products including pure niobium, the focus of this paper. CBMM’s position has been consolidated over three decades of producing high purity niobium metal ingots. The company supplies, among other products, commercial and reactor grade niobium ingots. One of the main uses of CBMM’s ingots is for the manufacture of particle accelerators (superconducting radio frequency – SRF – cavities), where the purity and homogeneity of niobium metal is essentially important for good performance. CBMM constantly strives to improve process controls and product quality, and is currently implementing innovations in production, research and development to further improve ingot quality. The main aim is to reduce the content of interstitial elements, such as nitrogen (N), oxygen (O), carbon (C), and hydrogen (H), starting with the raw materials through the final step of ingot production. CBMM held the first trial to produce the world’s largest-diameter niobium ingot (as cast 535 mm). The results of this initial trial presented very low levels of interstitial impurities (N, O, C, H), allowing the achievement of residual resistivity ratio (RRR) values very close to 300 in a six-melt process in an electron beam furnace. These values were reached with 850 ppm of tantalum. SRF cavities will be produced with this material in order to study the effect of low impurities and high RRR on the Q factor and accelerating gradient

Deuterium permeation and diffusion in high purity beryllium

International Nuclear Information System (INIS)

Abramov, E.

1990-05-01

The permeation rate of deuterium through high-purity beryllium membranes was measured using the gas-driven permeation technique. The time-dependent and the steady-state deuterium flux data were analyzed and the effective diffusivities of the samples were determined. A multilayer permeation theory was used in order to eliminate the surface oxide effects and the diffusion coefficients of the bulk beryllium were determined. The diffusion parameters obtained for the extra-grade beryllium samples (99.8%) are D 0 = 6.7 x 10 -9 [m 2 /s] and E D = 28.4 [KJ/mol]; and for the high-grade beryllium samples (99%) the parameters are D 0 = 8.0 x 10 -9 [m 2 /s] and E D = 35.1 [KJ/mol

Study of corrosion of aluminium alloys of nuclear purity in ordinary water, пart one

Directory of Open Access Journals (Sweden)

Pešić Milan P.

2004-01-01

Full Text Available Effects of corrosion of aluminum alloys of nuclear purity in ordinary water of the spent fuel storage pool of the RA research reactor at VINČA Institute of Nuclear Sciences has been examined in the frame work of the International Atomic Energy Agency Coordinated Research Project "Corrosion of Research Reactor Aluminum-Clad Spent Fuel in Water" since 2002. The study presented in this paper comprises activities on determination and monitoring of chemical parameters and radio activity of water and sludge in the RA spent fuel storage pool and results of the initial study of corrosion effects obtained by visual examinations of surfaces of various coupons made of aluminum alloys of nuclear purity of the test racks exposed to the pool water for a period from six months to six years.

High-Purity Fe3S4 Greigite Microcrystals for Magnetic and Electrochemical Performance

NARCIS (Netherlands)

Li, Guowei; Zhang, Baomin; Yu, Feng; Novakova, Alla A.; Krivenkov, Maxim S.; Kiseleva, Tatiana Y.; Chang, Liao; Rao, Jiancun; Polyakov, Alexey O.; Blake, Graeme R.; de Groot, Robert A.; Palstra, Thomas T. M.

2014-01-01

High-purity Fe3S4 (greigite) microcrystals with octahedral shape were synthesized via a simple hydrothermal method using a surfactant. The as-prepared samples have the inverse spinel structure with high crystallinity. The saturation magnetization (M-s) reaches 3.74 mu(B) at 5 K and 3.51 mu(B) at

NMR line broadening in solids by slowing down of spin fluctuations

International Nuclear Information System (INIS)

Mehring, M.; Sinning, G.; Pines, A.; California Univ., Berkeley

1976-01-01

The 109 Ag nuclear magnetic resonance line in a sample of polycrystalline AgF is observed to broaden substantially when the 19 F spins are irradiated near the magic angle in their rotating frame. This is due to the reduction of 19 F- 19 F dipolar coupling, which normally causes fluctuations in the 19 F- 109 Ag interactions (Abragam and Winter), inducing an exchange narrowing analogous to classical motional narrowing. The 109 Ag linewidths obtained over the entire motional range at different 19 F frequencies are compared with those calculated exactly from the ratio of second to fourth moment. (orig.) [de

Temperature dependence of the ESR linewidth in the paramagnetic phase (T{gt}T{sub C}) of R{sub 1{minus}x}B{sub x}MnO{sub 3+{delta}} (R=La,Pr; B=Ca,Sr)

Energy Technology Data Exchange (ETDEWEB)

Rettori, C.; Rao, D.; Singley, J.; Kidwell, D.; Oseroff, S.B. [San Diego State University, San Diego, California 92182 (United States); Causa, M.T. [Centro Atomico Bariloche and Instituto Balseiro 8400, San Carlos de Bariloche (Argentina); Neumeier, J.J.; McClellan, K.J. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Cheong, S. [ATT Bell Laboratories, Murray Hill, New Jersey 07974 (United States); Schultz, S. [University of California, San Diego, California 92037 (United States)

1997-02-01

Electron spin resonance (ESR) experiments in the paramagnetic phase of R{sub 1{minus}x}B{sub x}MnO{sub 3+{delta}} (R=La,Pr; B=Ca,Sr) show, for 1.1 T{sub C}{approx_lt}T{approx_lt}2T{sub C}, a linear T increase of the resonance linewidth, {Delta}H, in powders, ceramic pellets, and single crystals. Above {approximately}2T{sub C} a slowdown in the T increase of {Delta}H is observed. The data resemble the results found in other ferromagnetic insulators where the spin-lattice relaxation involves a single-phonon process. We find that the one-phonon process may account for the linear T dependence of the linewidth observed up to {approximately}2T{sub C}. A large T dependence of the resonance intensity above T{sub C} was found in all the samples studied, suggesting the existence of {ital spin clusters} in these compounds over a wide range of temperature. {copyright} {ital 1997} {ital The American Physical Society}

Shock loading influence on mechanical behavior of high purity iron

International Nuclear Information System (INIS)

Buy, Francois; Voltz, Christophe

2004-01-01

This paper proposes the analysis of shock wave effects for high purity iron. The method developed is based on the characterization of the mechanical behavior of as received and shocked material. Shock effect is generated through plate impact tests performed in the range of 4 GPa to 39 GPa on a single stage light gas gun or a powder gun. Therefore, as-received and impacted materials are characterized. A formalism proposed by J.R.Klepaczko and based on physical relations has been adopted to describe stress strain curves

Properties of structural steels melted out of high-purity charge

International Nuclear Information System (INIS)

Marchenko, V.N.; Sergeeva, T.K.; Kondakova, N.K.; Morozov, V.P.; Madorskij, L.L.

1993-01-01

A comparative evaluation has been made of impurities, mechanical properties and hydrogen embirittlement parameters for steels type 40Kh and 40KhS produced by electrometallurgical method with the use of direct reduced charge (DR-steels) and melted in an open-hearth furnace. Investigation results have shown that 40Kh and 40KhS Dr-steels have more coarse austenitic grains and experience more complete transformation of martensite into ferritic-pearlitic mixture on tempering. Threshold stresses increase 2.5 times due to purity enhancement at the expense of application of direct reduced charge

The ion-exchange obtaining of high purity samarium oxide

International Nuclear Information System (INIS)

Brzyska, W.; Soltysiak, I.; Cygan, J.

1987-01-01

The use of lactic acid - EDTA mixture as an eluent for the obtaining of high purity samarium oxide was studied. The studies were carried out at room temperature on cation exchange resin Wofatit KPS X 8. The best results were obtained for lactic acid (0,26 mol/dm 3 ) - EDTA (0,013 mol/dm 3 ) mixture at pH 3,3. As the result of 57% samarium concentrate elution with column load 1:3 and flow rate 0,4 cm/min, over 99% pure samarium oxide with 73% yield has been obtained. The yield of spectrally pure Sm 2 O 3 exceeded 45%. (author)

Subthermal linewidths in photoassociation spectra of cold alkaline-earth-metal atoms

International Nuclear Information System (INIS)

Machholm, Mette; Julienne, Paul S.; Suominen, Kalle-Antti

2002-01-01

Narrow s-wave features with subthermal widths are predicted for the 1 Π g photoassociation spectra of cold alkaline-earth-metal atoms. The phenomenon is explained by numerical and analytical calculations. These show that only a small subthermal range of collision energies near threshold contributes to the s-wave features that are excited when the atoms are very far apart. The resonances survive thermal averaging, and may be detectable for Ca cooled near the Doppler cooling temperature of the 4 1 P 1 S laser-cooling transition

Neutron activation determination of impurities in high-purity bismuth with separation of matrix in form of hydroxide

International Nuclear Information System (INIS)

Artyukhin, P.I.; Shavinskij, B.M.; Mityakin, Yu.L.

1979-01-01

The technique of neutron activation determination of 15 impurity elements (Au, Ag, Ba, Cd, Co, Cs, Cu, Hg, K, Na, Ni, Se, Sr, Te, Zn) in high-purity bismuth (impurity content is approximately 10 -6 -10 -10 %) is presented. Bismuth hydroxide precipitation by ammonia from nitric acid solutions was used to separate bismuth from alkali, alkaline earth metals and elements forming stable ammines. Gold, selenium and tellurium are isolated in the form of metals at reduction by muriatic hydrazine. Results of analyzing two samples of special purity bismuth are presented. Neutron flux comprised 0.8-1x10 13 n/cm 2 xs. Radiation time was equal to 90 hours

Obtaining water with a high degree of purity by using reverse osmosis

Directory of Open Access Journals (Sweden)

Nicolae Chirilă

2011-12-01

Full Text Available In this paper, we used the method of reverse osmosis in order to obtain water with a high degree of purity. For this aim, we used the TKA 20-120ECO device. We completed physic-chemical determinations for the water of supply, as well as for the water obtained after the osmosis process. The results that we obtained are relevant and interesting.

Analysis of the radiochemical purity of 18F-FDG by HPLC

International Nuclear Information System (INIS)

Chen Liguang; Tang Anwu; He Shanzhen; Chen Yulong

2001-01-01

The radiochemical purity (RCP) of 18 F-FDG is analyzed by HPLC. Eighty-five percent acetonitrile is used as the eluting solution. Carbon hydrate column is used as separation column. The t R of 18 F - is 6.50 min and 18 F-FDG is 9.00 min. HPLC take less time and has higher sensitivity than TLC for the same sample at the same time. So HPLC excels TLC in analyzing RCP of 18 F-FDG

A solvent-extraction module for cyclotron production of high-purity technetium-99m.

Science.gov (United States)

Martini, Petra; Boschi, Alessandra; Cicoria, Gianfranco; Uccelli, Licia; Pasquali, Micòl; Duatti, Adriano; Pupillo, Gaia; Marengo, Mario; Loriggiola, Massimo; Esposito, Juan

2016-12-01

The design and fabrication of a fully-automated, remotely controlled module for the extraction and purification of technetium-99m (Tc-99m), produced by proton bombardment of enriched Mo-100 molybdenum metallic targets in a low-energy medical cyclotron, is here described. After dissolution of the irradiated solid target in hydrogen peroxide, Tc-99m was obtained under the chemical form of 99m TcO 4 - , in high radionuclidic and radiochemical purity, by solvent extraction with methyl ethyl ketone (MEK). The extraction process was accomplished inside a glass column-shaped vial especially designed to allow for an easy automation of the whole procedure. Recovery yields were always >90% of the loaded activity. The final pertechnetate saline solution Na 99m TcO 4 , purified using the automated module here described, is within the Pharmacopoeia quality control parameters and is therefore a valid alternative to generator-produced 99m Tc. The resulting automated module is cost-effective and easily replicable for in-house production of high-purity Tc-99m by cyclotrons. Copyright © 2016 Elsevier Ltd. All rights reserved.

A novel FPGA-based bunch purity monitor system at the APS storage ring

International Nuclear Information System (INIS)

Norum, W.E.

2008-01-01

Bunch purity is an important source quality factor for the magnetic resonance experiments at the Advanced Photon Source. Conventional bunch-purity monitors utilizing time-to-amplitude converters are subject to dead time. We present a novel design based on a single field- programmable gate array (FPGA) that continuously processes pulses at the full speed of the detector and front-end electronics. The FPGA provides 7778 single-channel analyzers (six per rf bucket). The starting time and width of each single-channel analyzer window can be set to a resolution of 178 ps. A detector pulse arriving inside the window of a single-channel analyzer is recorded in an associated 32-bit counter. The analyzer makes no contribution to the system dead time. Two channels for each rf bucket count pulses originating from the electrons in the bucket. The other four channels on the early and late side of the bucket provide estimates of the background. A single-chip microcontroller attached to the FPGA acts as an EPICS IOC to make the information in the FPGA available to the EPICS clients.

Q2 anti Q2 states with relatively narrow widths

International Nuclear Information System (INIS)

Ono, Seiji.

1978-09-01

Using the mass formulas which correctly predict the mass of mesons and baryons the mass of diquark states is computed. From this mass spectrum the existance of the observed narrow baryonia and wide baryonia can be naturally understood. Other relatively narrow Q 2 anti Q 2 states are predicted to exist. (orig.) [de

Characteristics of 1.9-μm laser emission from hydrogen-filled hollow-core fiber by vibrational stimulated Raman scattering

Science.gov (United States)

Gu, Bo; Chen, Yubin; Wang, Zefeng

2016-12-01

We report here the characteristics of 1.9-μm laser emission from a gas-filled hollow-core fiber by stimulated Raman scattering (SRS). A 6.5-m hydrogen-filled ice-cream negative curvature hollow-core fiber is pumped with a high peak-power, narrow linewidth, linearly polarized subnanosecond pulsed 1064-nm microchip laser, generating a pulsed vibrational Stokes wave at 1908.5 nm. The maximum quantum efficiency of about 48% is obtained, which is mainly limited by the mode mismatch between the pump laser beam and the Stokes wave in the hollow-core fiber. The linewidths of the pump laser and the first-order vibrational Stokes wave are measured to be about 1 and 2 GHz, respectively, by a scanning Fabry-Perot interferometer. The pressure selection phenomenon of the vibrational anti-Stokes waves is also investigated. The pulse duration of the vibrational Stokes wave is recorded to be narrower than that of the pump laser. The polarization properties of the hollow-core fiber and the polarization dependence of the vibrational and the rotational SRS are also studied. The beam profile of the vibrational Stokes wave shows good quality.

Wave mixing spectroscopy

International Nuclear Information System (INIS)

Smith, R.W.

1980-08-01

Several new aspects of nonlinear or wave mixing spectroscopy were investigated utilizing the polarization properties of the nonlinear output field and the dependence of this field upon the occurrence of multiple resonances in the nonlinear susceptibility. First, it is shown theoretically that polarization-sensitive detection may be used to either eliminate or controllably reduce the nonresonant background in coherent anti-Stokes Raman spectroscopy, allowing weaker Raman resonances to be studied. The features of multi-resonant four-wave mixing are examined in the case of an inhomogeneously broadened medium. It is found that the linewidth of the nonlinear output narrows considerably (approaching the homogeneous width) when the quantum mechanical expressions for the doubly- and triply-resonant susceptibilities are averaged over a Doppler or strain broadened profile. Experimental studies of nonlinear processes in Pr +3 :LaF 3 verify this linewidth narrowing, but indicate that this strain broadened system cannot be treated with a single broadening parameter as in the case of Doppler broadening in a gas. Several susceptibilities are measured from which are deduced dipole matrix elements and Raman polarizabilities related to the 3 H 4 , 3 H 6 , and 3 P 0 levels of the praseodymium ions

Influence of the narrow {111} planes on axial and planar ion channeling.

Science.gov (United States)

Motapothula, M; Dang, Z Y; Venkatesan, T; Breese, M B H; Rana, M A; Osman, A

2012-05-11

We report channeling patterns where clearly resolved effects of the narrow {111} planes are observed in axial and planar alignments for 2 MeV protons passing through a 55 nm [001] silicon membrane. At certain axes, such as and , the offset in atomic rows forming the narrow {111} planes results in shielding from the large potential at the wide {111} planes, producing a region of shallow, asymmetric potential from which axial channeling patterns have no plane of symmetry. At small tilts from such axes, different behavior is observed from the wide and narrow {111} planes. At planar alignment, distinctive channeling effects due to the narrow planes are observed. As a consequence of the shallow potential well at the narrow planes, incident protons suffer dechanneled trajectories which are excluded from channeling within the wide planes, resulting in an anomalously large scattered beam at {111} alignment.

Homochiral Acyl Isocyanates as Diagnostic NMR Probes for the Enantiomeric Purity of Chiral Alcohols

Directory of Open Access Journals (Sweden)

Gregory H. P. Roos

2000-12-01

Full Text Available The first reported acyl and sulfonylisocyanates were developed and tested in reactions with chiral alcohols to afford diastereomeric carbamates. NMR analysis of these investigates the chemical shift discrimination that would allow these activated isocyanates to be used as diagnostic probes of enantiomeric purity.

On-line sodium and cover as purity monitors gas operating tools at EBR-II

International Nuclear Information System (INIS)

Smith, C.R.F.; Richardson, W.J.; Holmes, J.T.

1976-01-01

Plugging temperature indicators, electrochemical oxygen meters and hydrogen diffusion meters are the on-line sodium purity monitors now in use at EBR-II. On-line gas chromatographs are used to monitor helium, hydrogen, oxygen and nitrogen impurities in the argon cover gases. Monitors for tritium-in-sodium and for hydrocarbons-in-cover gas have been developed and are scheduled for installation in the near future. An important advantage of on-line monitors over the conventional grab-sampling techniques is the speed of response to changing reactor conditions. This helps us to identify the source of the impurity, whether the cause may be transient or constant, and take corrective action as necessary. The oxygen meter is calibrated monthly against oxygen in sodium determined by the vanadium wire equilibration method. The other instruments either do not require calibration or are self-calibrating. The ranges, sensitivity and response times of all of the on-line purity monitors has proven satisfactory under EBR-II operating conditions

Effect of initial grain size on dynamic recrystallization in high purity austenitic stainless steels

International Nuclear Information System (INIS)

El Wahabi, M.; Gavard, L.; Montheillet, F.; Cabrera, J.M.; Prado, J.M.

2005-01-01

The influence of initial microstructure on discontinuous dynamic recrystallization (DDRX) has been investigated by using high purity and ultra high purity austenitic stainless steels with various initial grain sizes. After uniaxial compression tests at constant strain rates and various temperatures, the steady state microstructure or the state corresponding to the maximum strain (ε = 1) attained in the test was analyzed by scanning electron microscopy aided with automated electron back scattering diffraction. Recrystallized grain size d rec and twin boundary fraction f TB measurements were carried out. The mechanical behavior was also investigated by comparing experimental stress-strain curves with various initial grain sizes. DDRX kinetics was described by the classical Avrami equation. It was concluded that larger initial grain sizes promoted a delay in the DDRX onset in the two alloys. It was also observed that the softening process progressed faster for smaller initial grain sizes. The effect of initial grain size is larger in the HP material and becomes more pronounced at low temperature

Optical filter finesses enhancement based on nested coupled cavities and active medium

Science.gov (United States)

Adib, George A.; Sabry, Yasser M.; Khalil, Diaa

2016-04-01

Optical filters with relatively large FSR and narrow linewidth are simultaneously needed for different applications. The ratio between the FSR and the 3-dB linewidth is given by finesse of the filter, which is solely determined by the different energy loss mechanisms limited by the technology advancement. In this work, we present a novel coupled-cavity configuration embedding an optical filter and a gain medium; allowing an overall finesse enhancement and simultaneous FSR and 3-dB linewidth engineering beyond the technological limits of the filter fabrication method. The configuration consists of two resonators. An active ring resonator comprises an optical gain medium and a passive resonator. In one configuration, the optical filter is the passive resonator itself. In a second configuration, the passive resonator is another ring resonator that embeds the optical filter. The presented configurations using a semiconductor optical amplifier are applied one time to a mechanically Fabry-Perot filter in the first presented configuration; and a second time to a fiber ring filter in the second presented configuration. The mechanical filter has an original 3-dB linewidth of 1nm and an FSR that is larger than 100nm while the enhanced linewidth is about 0.3nm. The fiber ring filter length is 4 m and directional coupler ratios of 90/10corresponding to a 3-dBlinewidth of about 4MHz and an FSR of 47 MHz. The enhanced 3- dBlinewidth of the overall filter configuration is 200kHz, demonstrating finesse enhancement up to20 times the original finesse of the filter.

Polarization and pressure effects in caesium 6S-8S two-photon spectroscopy

International Nuclear Information System (INIS)

Lee, Yi-Chi; Tsai, Chin-Chun; Chui, Hsiang-Chen; Chang, Yi-Hsiu; Chen, Ying-Yu

2010-01-01

This work analyses the effects of polarization and pressure in caesium 6S-8S two-photon spectroscopy. The linewidth was broadened and the frequency was shifted by a change of polarization states. The frequency shift and the linewidth broadening of the caesium 6S-8S two-photon transition were measured as a function of laser power using one single-frequency Ti:sapphire ring cavity laser, two caesium cells and two quarter-wave plates to ensure polarization states of light, and we showed that the linewidth cannot be evaluated just by fitting data to a Lorentzian shape. As determined by fitting the data to a Voigt profile, the natural linewidth is independent of the polarization states of the pump beams, the laser power and the pressure. Caesium 6S-8S two-photon transitions pumped by a circularly polarized beam have narrower linewidths and smaller shifts than those pumped by a linearly polarized beam. The light shift obtained by pumping with the circularly polarized beam is -6.75(57) Hz (mW mm -2 ) -1 , and that obtained by pumping with a linearly polarized beam is -7.25(45) Hz (mW mm -2 ) -1 . These results agree closely with theoretical calculations. The pressure shift is -588(387) Hz mPa -1 . This work shows how to evaluate two-photon transitions with a Voigt profile, and then helps us to understand two-photon transitions with different polarization states, and improve the signal quality obtained when they are used as frequency markers.

Narrowing the Gap in Outcomes: Early Years (0-5 Years)

Science.gov (United States)

Springate, Ian; Atkinson, Mary; Straw, Suzanne; Lamont, Emily; Grayson, Hilary

2008-01-01

This report was commissioned by the Local Government Association (LGA) to inform the Department for Children, Schools and Families (DCSF) and LGA work on "Narrowing the Gap." It focuses on early years' provision and presents findings from a review of the best evidence on narrowing the gap in outcomes across the five Every Child Matters…

Contribution to the study of the conductivity of high purity water

International Nuclear Information System (INIS)

Nens, Ch.

1964-01-01

In this work a study is made more particularly of two points: the production of high purity water and the estimation of this purity by means of conductivity measurements. As far as water purification is concerned it is observed that the de-ionisation produced by ion exchange resins in mixed beds leads to a water having a lower conductivity than that obtained by distillation. This low conductivity however, measured at the column exit before the water comes into contact with air is not stable. In fact the carbon dioxide in the water gives rise to an equilibrium with production of the ions HCO 3 - , CO 3 -- . These ions are retained during the passage of the water through the resins. They reappear again at the column exit as a result of the displacement of the hydration equilibrium of CO 2 ; because of this the conductivity of the water increases with time. The water obtained by successive distillations does not behave in the same way because no carbon dioxide is present. Distillation is however a costly purification process on an industrial scale, especially if large quantities of water have to be treated. The measurement of these low conductivities is very delicate. The method employed makes use of a direct current and gives reproducible results if care is taken to exclude interfering electric fields by screening the apparatus. (author) [fr

Experimental Study on Critical Power in a Hemispherical Narrow Gap

International Nuclear Information System (INIS)

Park, Rae-Joon; Ha, Kwang-Soon; Kim, Sang-Baik; Kim, Hee-Dong; Jeong, Ji-Hwan

2002-01-01

An experimental study of critical heat flux in gap (CHFG) has been performed to investigate the inherent cooling mechanism in a hemispherical narrow gap. The objectives of the CHFG test are to measure critical power from a critical heat removal rate through the hemispherical narrow gap using distilled water with experimental parameters of system pressure and gap width. The CHFG test results have shown that a countercurrent flow limitation (CCFL) brings about local dryout at the small edge region of the upper part and finally global dryout in a hemispherical narrow gap. Increases in the gap width and pressure lead to an increase in critical power. The measured values of critical power are lower than the predictions made by other empirical CHF correlations applicable to flat plate, annuli, and small spherical gaps. The measured data on critical power in the hemispherical narrow gaps have been correlated using nondimensional parameters with a range of approximately ±20%. The developed correlation has been expanded to apply the spherical geometry using the Siemens/KWU correlation

Narrow-width mechanism of a=5 Ξ-state

International Nuclear Information System (INIS)

Kumagai-Fuse, I.; Akaishi, Y.

1995-04-01

Narrow-width mechanism of ≡ 5 H is discussed by calculating conversion widths to all its possible decay channels. Since the conversion processes have small reaction Q values, the three- and four- body decays are strongly suppressed owing to small phase volumes available. Decay widths to the two-body channels are significantly reduced by the distortion of emitted-particle waves. This mechanism brings about a narrow width of ≡ 5 H. The total width is estimated to be 0.87 MeV, in which the largest contribution comes from the decay into the Λ 4 H * +Λ channel. (author)

1-GWh diurnal load-leveling superconducting magnetic energy storage system reference design. Appendix B: cost study, high-purity aluminum production

International Nuclear Information System (INIS)

Cochran, C.N.; Dawless, R.K.; Whitchurch, J.B.

1979-09-01

Cost information is supplied for aluminum with purities of 200, 2000, and 5000 residual resistivity ratio. Two production situations were used for each purity: (1) 1 x 10 6 kg/yr production rate with a 30-yr sustaining market and (2) 1 x 10 6 kg/yr production rate for 2 yrs only. These productions and purities are of interest for manufacturing devices for Superconducting Magnetic Energy Storage. The cost study results are presented as a range and include (1) the selling price of the aluminum for each case, (2) the cost of facilities including construction, engineering, and related costs, (3) the cost of money and depreciation (interest/amortization), and (4) the energy costs - the total of power and fuel. The range is affected by possible production variations and other uncertainties. Information is also given on plant location options and the preferred feed to the purification facility

Charge collection performance of a segmented planar high-purity germanium detector

Energy Technology Data Exchange (ETDEWEB)

Cooper, R.J. [Department of Physics, The University of Liverpool, Oliver Lodge Laboratory, Liverpool Merseyside L69 7ZE (United Kingdom)], E-mail: R.Cooper@liverpool.ac.uk; Boston, A.J.; Boston, H.C.; Cresswell, J.R.; Grint, A.N.; Harkness, L.J.; Nolan, P.J.; Oxley, D.C.; Scraggs, D.P. [Department of Physics, The University of Liverpool, Oliver Lodge Laboratory, Liverpool Merseyside L69 7ZE (United Kingdom); Lazarus, I.; Simpson, J. [STFC Daresbury Laboratory, Warrington, Cheshire WA4 4AD (United Kingdom); Dobson, J. [Rosemere Cancer Centre, Royal Preston Hospital, Preston PR2 9HT (United Kingdom)

2008-10-01

High-precision scans of a segmented planar high-purity germanium (HPGe) detector have been performed with a range of finely collimated gamma ray beams allowing the response as a function of gamma ray interaction position to be quantified. This has allowed the development of parametric pulse shape analysis (PSA) techniques and algorithms for the correction of imperfections in performance. In this paper we report on the performance of this detector, designed for use in a positron emission tomography (PET) development system.

Hot flow of a commercial-purity copper

International Nuclear Information System (INIS)

Garcia, V. G.; El Wahabi, M.; Cabrera, J. M.; Riera, L. M.; Prado, J. M.

2001-01-01

The objective of the study is to model the flow curve at high temperature of a commercial-purity copper which contains 297 ppm of phosphorus. For this purpose a theoretical model is applied to derive a constitutive equation that reliably predicts the behaviour at higher strain rates than experimentally tested. The test temperature range was from 873 K to 1223 K in increments of 50 K, using six true strain rates at every temperature, which span from 0.3 s''-1 to 0.001 s''-1. The hot flow tests were performed on a copper with a relatively large grain size (637 μm) but of similar scale to pertinent industrial processes. This metal presents two antagonistic phenomena during the hot working: strain hardening and softening by dynamic restoration, which in turns can be divided into dynamic recovery and dynamic recrystallization. A quantification of the mentioned mechanisms is done through the use of physically based constitutive equations. (Author) 20 refs

Narrow resonances and short-range interactions

International Nuclear Information System (INIS)

Gelman, Boris A.

2009-01-01

Narrow resonances in systems with short-range interactions are discussed in an effective field theory (EFT) framework. An effective Lagrangian is formulated in the form of a combined expansion in powers of a momentum Q 0 | 0 --a resonance peak energy. At leading order in the combined expansion, a two-body scattering amplitude is the sum of a smooth background term of order Q 0 and a Breit-Wigner term of order Q 2 (δε) -1 which becomes dominant for δε 3 . Such an EFT is applicable to systems in which short-distance dynamics generates a low-lying quasistationary state. The EFT is generalized to describe a narrow low-lying resonance in a system of charged particles. It is shown that in the case of Coulomb repulsion, a two-body scattering amplitude at leading order in a combined expansion is the sum of a Coulomb-modified background term and a Breit-Wigner amplitude with parameters renormalized by Coulomb interactions.

Purity and crystallinity of microwave synthesized antimony sulfide microrods

Energy Technology Data Exchange (ETDEWEB)

Martínez-Alonso, Claudia, E-mail: claudiamartinezalonso30@gmail.com [Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, Querétaro, 76010 (Mexico); Olivos-Peralta, Eliot U. [Instituto de Energías Renovables, Universidad NacionalAutónoma de México, Temixco, Morelos, 62580 (Mexico); Sotelo-Lerma, Mérida [Universidad de Sonora, Hermosillo, Sonora, 83000 (Mexico); Sato-Berrú, Roberto Y. [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, MéxicoD.F., 04510 (Mexico); Mayén-Hernández, S.A. [Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, Querétaro, 76010 (Mexico); Hu, Hailin, E-mail: hzh@ier.unam.mx [Instituto de Energías Renovables, Universidad NacionalAutónoma de México, Temixco, Morelos, 62580 (Mexico)

2017-01-15

Antimony sulfide (Sb{sub 2}S{sub 3}) is a promising semiconductor material for solar cell applications. In this work, microrods of Sb{sub 2}S{sub 3} were synthesized by microwave heating with different sulfur sources, solvents, temperature, heating rate, power, and solution concentration. It was found that 90% of stoichiometric Sb{sub 2}S{sub 3} can be obtained with thiourea (TU) or thioacetamide (TA) as sulfur sources and that their optical band gap values were within the range of 1.59–1.60 eV. The most crystalline Sb{sub 2}S{sub 3} were obtained by using TU. The morphology of the Sb{sub 2}S{sub 3} with TU the individual rods were exhibited, whereas rods bundles appeared in TA-based products. The solvents were ethylene glycol (EG) and dimethylformamide (DMF). EG generates more heat than DMF during the microwave synthesis. As a result, the Sb{sub 2}S{sub 3} obtained with EG contained a larger percentage of oxygen and smaller crystal sizes compared to those from DMF. On the other hand, the length and diameter of Sb{sub 2}S{sub 3} microrods can be increased by applying higher heating power although the crystal size did not change at all. In summary, pure and highly crystalline Sb{sub 2}S{sub 3} microrods of 6–10 μm long and 330–850 nm in diameter can be obtained by the microwave method with a careful selection of chemical and thermodynamic parameters of the synthesis. - Highlights: • Purity up to 90% of crystalline Sb{sub 2}S{sub 3} nanorods can be obtained by microwave heating. • The combination of solvent and sulfide type affects crystallinity & purity of Sb2S3. • The high pressure generated in microwave heating helps to form Sb{sub 2}S{sub 3} nanorods.

Purity and crystallinity of microwave synthesized antimony sulfide microrods

International Nuclear Information System (INIS)

Martínez-Alonso, Claudia; Olivos-Peralta, Eliot U.; Sotelo-Lerma, Mérida; Sato-Berrú, Roberto Y.; Mayén-Hernández, S.A.; Hu, Hailin

2017-01-01

Antimony sulfide (Sb_2S_3) is a promising semiconductor material for solar cell applications. In this work, microrods of Sb_2S_3 were synthesized by microwave heating with different sulfur sources, solvents, temperature, heating rate, power, and solution concentration. It was found that 90% of stoichiometric Sb_2S_3 can be obtained with thiourea (TU) or thioacetamide (TA) as sulfur sources and that their optical band gap values were within the range of 1.59–1.60 eV. The most crystalline Sb_2S_3 were obtained by using TU. The morphology of the Sb_2S_3 with TU the individual rods were exhibited, whereas rods bundles appeared in TA-based products. The solvents were ethylene glycol (EG) and dimethylformamide (DMF). EG generates more heat than DMF during the microwave synthesis. As a result, the Sb_2S_3 obtained with EG contained a larger percentage of oxygen and smaller crystal sizes compared to those from DMF. On the other hand, the length and diameter of Sb_2S_3 microrods can be increased by applying higher heating power although the crystal size did not change at all. In summary, pure and highly crystalline Sb_2S_3 microrods of 6–10 μm long and 330–850 nm in diameter can be obtained by the microwave method with a careful selection of chemical and thermodynamic parameters of the synthesis. - Highlights: • Purity up to 90% of crystalline Sb_2S_3 nanorods can be obtained by microwave heating. • The combination of solvent and sulfide type affects crystallinity & purity of Sb2S3. • The high pressure generated in microwave heating helps to form Sb_2S_3 nanorods.

Improving the radiochemical purity determination of 123I-labeled metaiodobenzylguanidine

International Nuclear Information System (INIS)

Luciana Carvalheira; Paulo Bechara Dutra; Paula Fernandes de Aguiar

2014-01-01

The HPLC method originally applied at the Nuclear Engineering Institute (IEN) for the radiochemical purity determination of 123iodine labeled m-iodobenzylguanidine ( 123 I-mIBG) takes 18.5 min. The final product release also depends on this result, and to facilitate this stage, we aimed to decrease this analysis time. We also intended to use fewer toxic compounds, if feasible. The optimization approach used herein was a combination of factorial and mixture designs to study simultaneously the selected variables. Analysis time, resolution and chromatograms aspect were the measured responses. The qualitative analysis of these responses provided the best chromatographic separation conditions that were 52 mM KH 2 PO 4 in a solution of ethanol and water (1:1), applying a flow rate of 0.50 mL min -1 and C18 column (4.6 × 250 mm, 5 μm). These optimum conditions not only decreased the analysis time in 61 %, but also allowed the reduction of mobile phase toxicity. To assure reliable data, method validation was performed for these conditions. The method has proved its specificity, the detection limit found was 3.70 × 10 -4 MBq mL -1 and the quantification limit has corresponded to 1.11 × 10 -3 MBq mL -1 . Repeatability and intermediate precision has not exceeded 3 and 5 %, respectively, and the accuracy has matched the interval of 95-105 %. This new method has been routinely applied in the radiochemical purity determination of 123 I-mIBG at IEN. (author)

Size filtering effect in vertical stacks of In(Ga)As/GaAs self-assembled quantum rings

International Nuclear Information System (INIS)

Ouerghui, W.; Melliti, A.; Maaref, M.A.; Martinez-Pastor, J.; Gomis, J.; Granados, D.; Garcia, J.M.

2006-01-01

We present a systematic study of closely In(Ga)As/InAs quantum rings (QRs) grown by molecular beam epitaxy (MBE). Photoluminescence (PL) experiments show a strong filtering effect in the ring being stacked and simultaneous linewidth narrowing for the appropriate layer thickness (thinner thickness). If the spacer thickness is further reduced, a strong coupling between the nanostructures is produced and the signal shifts to low energy

Purity determination of 60Co gamma irradiated atropine sulphate by different analytical techniques (Preprint No. RA.05)

International Nuclear Information System (INIS)

Balan, N.; Sharma, G.; Gopal, N.G.S.

1989-01-01

Some of the results obtained, employing high performance liquid chromatography (HPLC) are reported and some other methods to determine the purit y of radiation sterilized atropine sulphate in solid (I) and in aqueous solutions (0.1 per cent to 1.0 per cent w/v) (II) are also described. (I) and (II) were irradiated to graded doses of 10-100kGy and 5-20kGy respectively. The purity of irradiated sample (I) vis-a-vis unirradiated was determined using non aqueous potentiometric titration, thin layer chromatography, uv-vis spectrophotometry, HPLC and differential scanning calorimetry (DSC). Purity of (II) was examined only by HPLC vis-a-vis unirradiated aqueous solution. (author). 3 figs

Fabrication and research of high purity germanium detectors with abrupt and thin diffusion layer

International Nuclear Information System (INIS)

Rodriguez Cabal, A. E.; Diaz Garcia, A.

1997-01-01

A different high purity germanium detector's fabrication method is described. A very thin diffusion film with an abrupt change of the type of conductivity is obtained. The fine diffusion layer thickness makes possibly their utilization in experimental systems in which all the data are elaborated directly on the computer. (author) [es

Influence of Storage Temperature on Radiochemical Purity of 99mTc-Radiopharmaceuticals.

Science.gov (United States)

Uccelli, Licia; Boschi, Alessandra; Martini, Petra; Cittanti, Corrado; Bertelli, Stefania; Bortolotti, Doretta; Govoni, Elena; Lodi, Luca; Romani, Simona; Zaccaria, Samanta; Zappaterra, Elisa; Farina, Donatella; Rizzo, Carlotta; Giganti, Melchiore; Bartolomei, Mirco

2018-03-15

The influence of effective room temperature on the radiochemical purity of 99m Tc-radiopharmaceuticals was reported. This study was born from the observation that in the isolators used for the preparation of the 99m Tc-radiopharmaceuticals the temperatures can be higher than those reported in the commercial illustrative leaflets of the kits. This is due, in particular, to the small size of the work area, the presence of instruments for heating, the continuous activation of air filtration, in addition to the fact that the environment of the isolator used for the 99m Tc-radiopharmaceuticals preparation and storage is completely isolated and not conditioned. A total of 244 99m Tc-radiopharmaceutical preparations (seven different types) have been tested and the radiochemical purity was checked at the end of preparation and until the expiry time. Moreover, we found that the mean temperature into the isolator was significantly higher than 25 °C, the temperature, in general, required for the preparation and storage of 99m Tc-radiopharmaceuticals. Results confirmed the radiochemical stability of radiopharmaceutical products. However, as required in the field of quality assurance, the impact that different conditions than those required by the manufacturer on the radiopharmaceuticals quality have to be verified before human administration.

Analytical approximations for wide and narrow resonances

International Nuclear Information System (INIS)

Suster, Luis Carlos; Martinez, Aquilino Senra; Silva, Fernando Carvalho da

2005-01-01

This paper aims at developing analytical expressions for the adjoint neutron spectrum in the resonance energy region, taking into account both narrow and wide resonance approximations, in order to reduce the numerical computations involved. These analytical expressions, besides reducing computing time, are very simple from a mathematical point of view. The results obtained with this analytical formulation were compared to a reference solution obtained with a numerical method previously developed to solve the neutron balance adjoint equations. Narrow and wide resonances of U 238 were treated and the analytical procedure gave satisfactory results as compared with the reference solution, for the resonance energy range. The adjoint neutron spectrum is useful to determine the neutron resonance absorption, so that multigroup adjoint cross sections used by the adjoint diffusion equation can be obtained. (author)